JP5034732B2 - Speaker diaphragm and speaker using the same - Google Patents

Description

  The present invention relates to a loudspeaker diaphragm used in various kinds of audio equipment and video equipment, and an acoustic reproduction loudspeaker using the loudspeaker diaphragm.

  In the recent audio industry and the automobile industry equipped with audio equipment, the quality of sound played from speakers has improved dramatically due to the widespread use of digital equipment.

  Such a conventional speaker will be described with reference to a side sectional view of the speaker shown in FIG.

  According to the figure, the magnetic circuit 1 includes a bottom plate 1a provided with a center pole, an annular magnet 1b bonded and bonded to the bottom plate 1a, and an outer periphery of the center pole 1a bonded and bonded to the annular magnet 1b. And an annular upper plate 1c having an inner periphery forming a magnetic gap 1d.

  The frame 2 is formed by metal plate or resin molding, and is adhesively bonded to the upper plate 1 c of the magnetic circuit 1.

  The speaker diaphragm 3 has an outer periphery adhesively bonded to the frame 2 via the edge 4, and an inner periphery adhesively bonded to a voice coil 5 fitted in the magnetic gap 1 d of the magnetic circuit 1.

  The voice coil 5 is provided with a damper 6 whose inner periphery is adhesively bonded to the voice coil 5 and whose outer periphery is adhesively bonded to the frame 2 to support the vertical drive of the voice coil 5.

  The speaker configured as described above moves the voice coil 5 up and down by inputting an audio signal from the outside to both ends (not shown) of the coil portion 5 a of the voice coil 5, and the speaker diaphragm 3. The sound is emitted by moving up and down.

  The above-mentioned trends of audio equipment and video equipment manufacturers for speakers are higher sound quality, lighter weight, and environmentally friendly.

  In order to realize the sound quality requirement that is the user's need in order to achieve high sound quality, it is urgent to develop a speaker diaphragm that is a component of a loud speaker that determines the sound quality.

  The development of the speaker diaphragm has a merit that it is easy to control the sound quality with high accuracy, and hence a speaker diaphragm made of paper (hereinafter, the speaker diaphragm made of paper is hereinafter referred to as a “vibration plate”). A lot of development is underway.

  Pulp, which is the material used for these diaphragms, has been obtained through a beating process (including chemical beating (cooking) using chemicals such as alkali digestion) from conifers because of its abundant supply. Kraft pulp is used, which spurred a shortage of conifers, which has a very slow growth rate amid growing demand.

  On the other hand, bamboo has many kinds and quantities all over the world due to its vigorous reproductive potential and rapid growth, and in a particular area, bamboo forests are screaming for their damage.

  Bamboo grows very fast compared to conifers, and those with a bamboo level that is less than one year old are less rigid and lack toughness, but they are stiff and tough after one year. It has the stable physical property provided with.

  In addition, it has the advantage that the original bamboo forest can be regenerated immediately after cutting, and it does not lead to a situation that adversely affects the local environment like cutting coniferous forest.

  Rather, it would be desirable for the global environment to cut off bamboo forests that had grown too much to eliminate bamboo damage.

  Although these bamboos have been developed for a long time, their bamboo and younger ones that are less than one year old are often used for food and other purposes because of their softness and ease of processing. It was often used in the direction.

  However, because of the difficulty of processing due to its rigidity, it has been found that only a part of building materials and bamboo crafts can use the bamboo that has grown more than 1 year old. It also led to harm, and application development was urgent.

  As for the application to the diaphragm, although it has been tackled on the cocoon and juvenile level within 1 year of bamboo because of the ease of defibration of bamboo fiber, it has been effective to some extent, but it becomes the center of the diaphragm It was not reached.

  The reason for this is that in order to bring out the characteristics of the original bamboo fiber, it is more than 1 year old when the bamboo age is more than 1 year old. It is effective to use grown bamboo fiber with toughness, but the conventional diaphragm manufacturing method cannot fully utilize the features of the original bamboo fiber, satisfying the trendy sound quality requirements It was because it was not possible.

For example, Patent Document 1 is known as prior art document information related to a diaphragm using bamboo.
JP 2000-324591 A

  The diaphragm using kraft pulp obtained from the above-mentioned conifer is easy to manufacture, but in the wet press method of heating and pressurizing after paper making, the thickness of the diaphragm itself tends to be reduced by heating and pressurization. Yes, it was a disadvantageous method for low-frequency reproduction.

  That is, it is a well-known fact that if the cone paper has the same caliber and the same weight, the low-band regeneration capability is improved by improving the bending rigidity due to the thick cone surface thickness. Since the thickness cannot be increased, the diaphragm is disadvantageous for low-frequency reproduction.

  Therefore, in the diaphragm using the conventional kraft pulp, in order to finish the thickness of the diaphragm itself with the same diameter and the same weight thickly, generally, an oven method that does not pressurize after paper making is adopted. In the above construction method, it takes a lot of man-hours and has become an expensive product.

  In addition, there is a problem that the thickness of the diaphragm itself tends to be non-uniform.

  In addition, there is another semi-press method for finishing the diaphragm itself with a thick surface, which does not require much man-hours and the thickness of the diaphragm itself is uniform, but mold accuracy is required and the mold itself is expensive. In addition, it has a problem that it is difficult to set and requires highly skilled work.

  There are various problems in the use of the bamboo resources described above.

  Bamboo fiber has rigidity and toughness, but the diaphragm made by beating, papermaking, and wet press, like conventional conifers, is no different from the diaphragm made by conventional papermaking. Similarly, the reproduction of the low frequency characteristics was insufficient.

  In addition, because of the ease of processing, the papermaking diaphragm using bamboo that is less than one year old is used only as an edible material, and because of its low rigidity and toughness, it makes use of the characteristics of bamboo. It could not be used as.

  The present invention solves the above-mentioned problems, makes it possible to provide a papermaking diaphragm capable of improving the low-frequency reproduction ability as a speaker by utilizing the rigidity and toughness that are the characteristics of bamboo fiber, and a material. The purpose of the present invention is to provide a loudspeaker diaphragm that is friendly to the global environment and that can be stably supplied.

Papermaking present invention in order to solve the above problems, at least, it is mechanically beaten only rows that have generated bamboo fiber in the beating process in the paper making process, including the pulp retains at least lignin more than 10 wt% or more 50 wt% Further, the diaphragm for speaker is formed by heating and pressurizing.

The pulp, Ri your include those pulping only mechanical beating least 50 wt%, it is not performed chemical treatment such as alkaline cooking, which has been performed in the conventional diaphragm (beating), a bamboo A diaphragm for a speaker is constructed without losing rigidity or toughness.

As described above, the vibration is formed by forming a diaphragm by wet press pressurizing after heating and pressurizing after making paper containing 50WT% or more of pulped material that is made by mechanically beating bamboo fiber having rigidity and toughness. While maintaining the necessary bending rigidity, Young's modulus, and tensile strength for the plate, it can provide the same surface thickness as the above-mentioned open method of securing the surface thickness, and it is a blend of pulp made by mechanical beating of bamboo fibers only By controlling the rate, it is also possible to control the surface thickness (control of the reproduction band in the low sound range).

As described above, the diaphragm of the present invention is a bamboo fiber pulp that has been mechanically beaten in the beating process in the paper making process and has not been subjected to chemical treatment , and at least 10 wt% of lignin is retained. Is made by making paper containing 50 WT% or more , and it is possible to increase the thickness of the diaphragm and improve the bending rigidity without using a special method or mold. Area reproduction ability can be improved.

  Furthermore, the speaker diaphragm of the present invention can provide a papermaking diaphragm for a speaker that is inexpensive and friendly to the global environment by using a plant environment resource called bamboo.

  The present invention will be described below with reference to FIG.

(Embodiment 1)
In the following, the present invention will be described with reference to the side sectional view of the speaker of FIG.

  The difference between the prior art and the present embodiment lies in the diaphragm 7, and the rest is the same as the prior art.

  Diaphragm 7 was obtained by mechanically beating bamboo over 1 year old and mixing and papermaking into kraft pulp obtained from conifers. Various types of diaphragm 7 were prepared as follows for a 16 cm caliber diaphragm. The speaker of FIG. 1 was assembled and the performance was compared.

(1) Diaphragm (1)
Bamboo fibers obtained by mechanized beating were mixed and papered at 5 wt%, and heated and pressed with a wet press.

(2) Diaphragm (2)
Bamboo fibers obtained by mechanized beating were mixed and paper-made at 30 wt%, and heated and pressed with a wet press.

(3) Diaphragm (3)
Bamboo fibers obtained by mechanized beating were mixed and paper-made at 50 wt%, and heated and pressed by a wet press.

(4) Diaphragm (4)
A bamboo fiber obtained by mechanized beating was mixed and made into a paper of 100 wt% and obtained by heating and pressing with a wet press.

(5) Diaphragm (5) (Comparative example)
Paper was made from 100% kraft pulp obtained through chemical beating (digestion) and mechanical beating described in the prior art, and heated and pressurized by a wet press.

  In addition, as a pulp material other than bamboo fibers of the diaphragms (1) to (4), kraft pulp used in the diaphragm (5) is used.

  In addition, there are various methods of mechanical beating for making bamboo fiber, but a beater was used.

  As a result of comparing speakers made with diaphragms (1) to (4) based on the speaker assembled with diaphragm (5), which is a comparative example, the sound quality in the low-frequency reproduction band is diaphragm (4) → vibration The ranking was as follows: plate (3) → diaphragm (2) → diaphragm (1) → diaphragm (5) (comparative example).

  The diaphragm (5) manufactured as a comparative example has a diaphragm thickness of 0.30 mm, and the diaphragm (4) has a thickness of 0.5 mm, which is approximately 1.7 times that of the diaphragm (5). In (3), the thickness was 0.36 mm and about 1.2 times that of the diaphragm (5), which was thicker than the comparative example (the weight was about 2.2 g in all cases).

  It is known that if the diaphragm has the same diameter and the same weight, the bending rigidity of the diaphragm is improved by increasing the thickness of the diaphragm, and the sound quality in the low-frequency reproduction band is improved. This is also confirmed in the comparison.

  In the diaphragm (3) and the diaphragm (4), the difference in thickness from the diaphragm (5) as a comparative example was remarkable, and the improvement in bending rigidity was also remarkable.

  Also in the diaphragm (2), a slight difference in thickness was confirmed (thickness: 0.33 mm), and as described above, it was confirmed that the sound quality was superior to that of the diaphragm (5) as a comparative example.

  Further, it was confirmed that the diaphragm (1) was superior in sound quality to the diaphragm (5), but the thickness was almost the same as that of the diaphragm (5).

  From the above results, the diaphragm (1) is the effect of mixing bamboo fiber itself, and for the diaphragm (2) to diaphragm (4), the thickness of the diaphragm itself depends on the amount of bamboo fiber mixed. It was confirmed that this led to an improvement in sound quality.

  Although the same wet press method was used for heating and pressurization, the difference in the thickness of each diaphragm was due to the rigidity and toughness of the bamboo itself that resisted the press by the wet press method. Thus, it is considered that the springback effect of the material itself of the diaphragm itself appears remarkably.

  This is because the conventional chemical beating (cooking) dissolves lignin, which is a useful component of bamboo, and impairs the inherent rigidity and toughness of bamboo. The thing only by beating has shown that bamboo's original rigidity and toughness can be utilized by mixing 5 wt% or more of this bamboo.

  In addition, the thickness of the diaphragm can be adjusted even in the wet press method in which heating and pressurization is performed using the same mold by adjusting the blended amount of bamboo fiber obtained by this mechanical beating to at least 30 WT% to 100 WT%. Thus, it was confirmed that a predetermined sound quality in the low sound band can be stably obtained.

  In other words, by adjusting the amount of bamboo fiber pulp, it is easy to control the sound quality of low-frequency reproduction-oriented products and mid-range reproduction-oriented products by controlling the cone surface thickness even when using the same construction method and the same mold. It was confirmed that it could be done.

  As materials to be mixed other than the bamboo fiber pulp of the present invention, known materials such as UKP, NKP coniferous and hardwood wood pulp, natural fibers such as Ganpi, hemp, kenaf, and kapok, and chemical fibers can be used. These may be those of the beating process described in the prior art (conventional processing in which mechanical beating is performed through chemical beating (cooking)).

  Moreover, the bamboo fiber which passed through the conventional beating process called mechanical beating after chemical beating (digestion) may be used (The bamboo fiber which passed through the conventional beating process can be used as a pulp material for papermaking only. ).

  In the above description, the present invention has been described as performing paper making by mechanically beating bamboo, but chemical treatment as a preparatory work for facilitating feathering by mechanically beating bamboo fibers is within the scope of the present invention. Enter.

  That is, even alkali soaking performed before mechanical beating is not intended to make bamboo pulp directly, and does not affect the amount of bamboo lignin described above. The auxiliary chemical treatment that is easily performed falls within the scope of the present invention because the beating itself is performed mechanically.

  That is, it is desirable to maintain the amount of lignin unique to the bamboo, but the lignin is dissolved to less than 6 WT% as in the case of conventional alkali digestion, and the original rigidity and toughness of the bamboo of the present invention cannot be utilized. If the amount of lignin of the bamboo fiber after auxiliary chemical treatment that facilitates pulping by mechanical beating is 10 WT% or more, the bamboo fiber before mechanical beating of the present invention Can be used as

  In the above embodiment, a cone-shaped diaphragm is used as a speaker and an external magnet type speaker is used as a magnetic circuit. However, the present invention is a paper-making speaker diaphragm. As long as the speaker is used, it can be applied to any known speaker. That is, the magnetic circuit may be an outer magnet type or an inner magnet type, and the shape of the magnetic circuit may be a round shape or an elongated shape, and the overall shape of the speaker may be an elliptical shape in addition to the cone-shaped embodiment. It can be used for a wide variety of speakers such as track-type and track-type speakers.

  The diaphragm and speaker for sound reproduction according to the present invention need to be improved in quantity sensitivity such as improvement in sound quality and characteristics by a diaphragm having high bending rigidity, improvement in sound pressure level in the low sound range, and further high quality and reliability are required. It can be used for a wide range of equipment such as audiovisual equipment, information communication equipment, and mounted equipment such as automobiles, and can also be applied to any known loudspeaker using a papermaking diaphragm as a loudspeaker.

Sectional drawing of the speaker in one embodiment of this invention Cross-sectional view of a conventional speaker

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Magnetic circuit 1a Bottom plate 1b Magnet 1c Top plate 2 Frame 4 Edge 5 Voice coil 6 Damper 7 Diaphragm

Claims (2)

Are only rows that have generated mechanical beating bamboo fiber in the beating process in the papermaking process, the pulp retains at least lignin more than 10 wt%, and paper and混抄least 50 wt%, speaker formed by heat and pressure Diaphragm. A speaker using the speaker diaphragm according to claim 1 .

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