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TECHNICAL FIELD The present invention relates to a vibrator used for a speaker such as a
diaphragm and a center cap. 1 and I An electrodynamic speaker as shown in the sectional view of
FIG. 1 has been known conventionally. In such an electrodynamic speaker, the pole piece 2 is
mounted at the central portion of the back plate 1, and the magnet 3 is mounted at the
peripheral portion thereof. The plate 4 is placed on the magnet 3 to form a magnetic gap with
the pole piece 2. A voice fill bobbin 6 carrying a voice coil 5 is vibratably inserted into the
magnetic gap, and the voice coil bobbin 6 is supported by a damper 7. A cone-shaped diaphragm
8 is coupled to the voice coil bobbin 6 at its central portion, and a center cap 9 is crowned at its
end. The peripheral edge of the aperture of the cone-shaped diaphragm 8 is supported by the
frame 11 via the edge 10. The edge 10 is further secured to the frame 11 by means of a gasket
12. The voice coil lead is connected to a terminal 14 provided on the side surface of the frame 11
through the tinsel wire 13. In such a speaker, the diaphragm 8, the center cap 9 and the voice
coil bobbin 6 are speaker vibrating bodies. In order to faithfully convert an input signal to the
voice coil 5 into an acoustic output in an electrodynamic speaker, it is necessary that these
speaker vibrators make ideal piston motion as a body. This means that the vibrating body, in
particular the diaphragm and the center cap, must be rigid and at the same time have adequate
internal losses to dampen unwanted vibrations. Further, in order to enhance the electroacoustic
conversion, it is desirable that the diaphragm and the center cap have a large Young's modulus
and an appropriate internal loss. In recent years, the application of such a speaker has been
greatly expanded, and a speaker vibrator having performance of high rigidity and high elasticity
is strongly demanded from the market also with respect to a vibrator. Since a vibrator having
desirable conditions as a vibrator, that is, weight reduction of the vibrator, high rigidity, high
elasticity, high internal loss, and other dynamic properties is required, recently, metal
diaphragms made of boron, aluminum, beryllium or the like Some films use polymer films.
However, although metal and polymer film materials show high numerical values for elastic
modulus etc., they are limited to some high frequency band reproduction diaphragms or center
caps due to inferior properties such as other density and internal loss. . Therefore, as a full range
vibration body such as a woofer's diaphragm, a vibration body made of a fiber material,
particularly a pulp fiber, whose physical properties can be controlled by a papermaking method
or a drying method is widely used.
In general, the fibers used in these vibrators are mainly fibers obtained from natural III, so-called
wood valves. Many of these wood pulps are mixed with bast IIN such as manila hemp and kapok.
In addition, sulfate pulp (rartPtllp), which is a chemical pulp, is divided into unbleached sulfate
valve (Unbleached Kraft Pulp (UKP)) and bleached sulfate pulp (Raft Pulp (BKP)). N (Coniferous
wood) wood and L (hard leaf wood) wood chips for wood chips, and a mixed liquid of sodium
hydroxide and sodium sulfide for cooking liquor to lignin as thio lignin to elute lignin as thio
lignin, consisting of fibers mainly composed of cellulose etc. Get a salt valve. The outline of a
manufacturing method puts a chip ¦ tip in a kettle, adds the said cooking liquor, and steames at
170 degreeC and 7-8 kg / Cm2 grade. After steaming, the fiber portion is washed with water and
separated to obtain unbleached sulfate pulp (tJKP). Furthermore, bleached with chlorine, sodium
hydroxide, bleached powder or the like to obtain bleached sulfate valve (BKP). Sulfate pulp is
removed from cellulose analogues with low degree of polymerization by digestion. Alkaline
pentosan remains in the pulp in large amounts, but the low degree of polymerization of cellulose
analogues removed during digestion tends to be more easily degraded than residual bentosane.
However, in the case of a vibrator which is mainly made of wood pulp and mixed with
unbleached sulfate valve etc., there is a limit even if it is desired to obtain the above-mentioned
preferable condition as the vibrator, and the desired output sound pressure characteristics can
not be obtained. As an example of a conventional diaphragm, for example, a woofer diaphragm of
aperture 10C11 is manufactured using the following mixture of pulp as a main raw material.
Unbleached sulfate valve (freeness 50 ° SR) ········· 85wt% Manila hemp pulp (freeness 75 ° SR)
········· 15wt% mixture furnish or main raw Table 1 shows the dynamic properties of the diaphragm
obtained by papermaking using a conical papermaking tool, shaping and drying. As shown in
Table 1 Table 1 <Conventional mixing stock could not obtain a moving plate having preferable
physical properties as a vibrator such as high rigidity, high elasticity and high internal loss.
SUMMARY OF THE INVENTION It is an object of the present invention to provide a loudspeaker
vibrator having low density, high rigidity and high internal loss. The vibrator of the present
invention is characterized in that it can be obtained by mixing an unbleached sulfate valve and
flax pulp and using the mixture as a main material. Below, an example of the present invention is
described based on an attached drawing and the following tables.
As a speaker vibrating body of the present embodiment, a cone-shaped diaphragm of a woofer of
aperture 10C1 is manufactured. FIG. 2 is a flow chart showing the manufacturing process of this
embodiment. First, as preparation process S1, flax to which a 20% Na2SO3 solution = 4% NaOH
solution has a liquid ratio of 1 near is added to flax with a temperature of 160 ° C. for 4 hours,
and after digestion, the cooking solution is added Wash thoroughly to pulp flax. Next, 1.5 kG of
flax pulp (Flax Plul) obtained by subjecting to pulping to the pre-refining step S2 is put into a
predetermined beating machine, and is beaten for 30 minutes so as not to impair the physical
properties of the pulp. Adjust the desired degree of beating to 75 ° SR with a shopper type
degree of freeness measurement device. Next, as the simultaneous refining process S, unbleached
sulfate pulp (UKP) which has been swelled for about 10 minutes is prepared in advance, and the
unbleached sulfate pulp 8.5 kG is used as the fly bar of a beating machine carrying the flax pulp.
The roll is UP and charged into the beating machine, the fly bar roll of the beating machine is
adjusted again at a pulp concentration of about 4%, and the beating machine is beaten for 90
minutes to adjust the beating degree to 50 ° SR. Next, in the paper making process S4, the
adjusted stock is dyed to a predetermined color tone using a sulfur dye, and the adjusted stock is
adjusted to a pulp solution having a paper density of about 0.3%, and it is made conical in
advance. The vibrating plate is made with a molded 10CII diameter netting tool. Next, in the
drying step S5, using a predetermined mold, heat is applied by heating at a mold temperature of
180 to 200 ° C. at a press pressure of 3 kQ / Cm 2 and dried. Next, a moistureproof solution
having the following resin composition is prepared as the moistureproofing process S6. Aromatic
solvents ····································································· 7.0% glycol (high boiling point) ·············・ 4.0%
ketones ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・
・ ・ ・ ・ ・ 3.8% plasticizer (D OP)-・ ・ ・ ・ ・ 1.0% resin ..... The diaphragm made of 1.0%
is immersed in the moistureproof solution for about 10 minutes to make the diaphragm
moistureproof. Next, in the drying step S7, drying is performed about 10 degrees using hot air at
a temperature of 90 to 100 ° C. by a drier to fix the moistureproof solution to the fibers of the
diaphragm. Finally, in the forming step S8, the predetermined inner and outer diameters of the
diaphragm are cut and formed to obtain the diaphragm of the present embodiment. In Table 2, a
sample of 1.0CIX4.5CI11 was cut out of the diaphragm of this embodiment prepared as
described above, and the Young's modulus, internal loss, etc. were measured by the vibration
lead method in an environment of temperature 20 ° C. and humidity 60%. The measured results
are shown.
The diaphragm of this example shows a remarkable improvement of 98% in Young's modulus,
38% in propagation velocity / E / ρ, and 22% in internal loss, as compared with the values of the
conventional diaphragm in Table 1. ing. FIG. 3 is a graph showing the frequency characteristics
when assembled to the diaphragm of the present embodiment and the conventional loudspeakers
shown in Table 1 of the diaphragm metal. In the figure, curve A shows the characteristics of the
diaphragm of this embodiment, and curve B shows the characteristics of the conventional
diaphragm. As shown in the drawing, the diaphragm of this embodiment has improved
characteristics in the vicinity of 2000 to 5000 H 2 as compared with the conventional
diaphragm, and the band is broadened to significantly improve the performance. This is because
in the diaphragm of this embodiment, the increase in rigidity and the improvement in internal
loss are achieved. Flax fibers, which are bast fibers, have many streaks and knots on their
surface, and the cross section is polygonal. The tensile strength of flax fibers is almost twice that
of cotton fibers, but the elongation is extremely low. There are various flax fiber colors, but light
yellowish brown is the best. Bleaching causes the pectin in the fiber to degrade, thereby reducing
the weight and reducing the strength. Therefore, in order to exert strength, it is preferable not to
bleach. The Young's modulus, propagation velocity and internal loss are shown in Figure 1 in
terms of the physical properties of diaphragms obtained by mixing conventional wood valves, in
particular other bast fibers (tripolar, manila hemp) with unbleached sulfate valves. The numerical
value shown is almost the limit value. However, in the diaphragm of the present embodiment, the
values of Young's modulus and propagation speed show values comparable to those of the metal
diaphragm, and the internal loss is significantly improved over general pulp diaphragms. The
density is also decreasing. Therefore, the diaphragm of the present embodiment can be said to be
a diaphragm which is reduced in weight and has high rigidity, high elastic modulus, and high
internal loss. Further, the diaphragm of the present embodiment is excellent in physical
properties such as bending resistance and tensile strength, is also rich in durability, and can be
widely used as a diaphragm for a speaker from a lighter to a woofer. In the above embodiment,
the diaphragm is manufactured and described as the speaker vibrating body, but it is apparent
that the same effect can be obtained also with the center cap. Effect of the Invention As described
above, according to the present invention, it is a vibratory body obtained by making a mixture of
the flax pulp digested by the soda method using sodium hydroxide and the unbleached sulfate
valve and simultaneously beating it. Therefore, a vibrator having physical properties superior to
that of a diaphragm manufactured by the conventional mixed paper making with an unbleached
sulfate valve is obtained.
Brief description of the drawings
FIG. 1 is a cross-sectional view of an electrodynamic speaker, FIG. 2 is a flowchart showing the
manufacturing process of this embodiment, and FIG. 3 is a diaphragm of this embodiment and
the conventional vibration pseudonym shown in Table 1. It is a graph which shows the frequency
characteristic at the time of assembling to each speaker.
Explanation of symbols of main parts 1 ··· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·
· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · voice coil 6 ...... voice coil bobbin 7 ...... damper 8 ...... cone-
shaped diaphragm 9 ...... center cap 10 ...... edge 11 ..... · Frame 12 · · · · · · · · · · · · · · · · · · · · · · · · · · · ·
· · · · · · · · · · · · · · · terminal