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DESCRIPTION JPH06178386
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
diaphragm for a cone speaker and a method of manufacturing the same.
[0002]
2. Description of the Related Art In general, it is preferable that the material of the diaphragm for
a cone speaker be lightweight and have appropriate internal loss and high rigidity. Therefore,
kraft paper made of kraft pulp, which has excellent properties in terms of internal loss and
specific gravity, has been widely used. By the way, when manufacturing a diaphragm made of
kraft paper, first, wood chips are digested with a chemical and then beaten into kraft pulp, and
the kraft paper obtained by rolling up the pulp is a diaphragm of a predetermined shape. Was
press-formed.
[0003]
However, in the above-described conventional diaphragm, the wood fibers are chemically
changed by chemicals and the wood fibers are damaged, so that the sound quality is deteriorated.
Also, with the conventional diaphragm, it was not possible to bring the tone closer to a live
instrument. Furthermore, since the conventional diaphragm was made of kraft paper, there was
also a problem that it lacked a sense of luxury.
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[0004]
Also, in the prior art, wood chips were digested with chemicals and then beaten into kraft pulp,
and kraft paper from which this pulp was pulled up was press-formed on a diaphragm of a
predetermined shape, so a diaphragm In addition to the large number of manufacturing
processes, there is also the problem of pollution due to waste liquid because chemicals are used
during the digestion of wood chips. An object of the present invention is to provide a diaphragm
for a cone speaker that can solve the above problems and a method of manufacturing the same.
[0005]
SUMMARY OF THE INVENTION In order to achieve the above object, the feature of the
diaphragm for a cone speaker of the present invention is that it is composed of a thin sheet of
wood formed in the shape of a diaphragm. A plurality of thin wood plates may be provided, and
these thin wood plates may be arranged in parallel in the radial direction of the diaphragm. In
addition, there may be a plurality of lumber lamellae, and these lamellae laminae may be
overlapped and bonded in the central axis direction of the diaphragm. Furthermore, adjacent
wood veneers may be crossed. In addition, the material of at least one of the plurality of lumber
lamina may be different from the material of the other lumber lamina.
[0006]
Furthermore, a thin sheet of wood may be superposed on and bonded to a diaphragm for a cone
speaker made of a material other than a thin sheet of wood. The feature of the method for
manufacturing a diaphragm for a cone speaker according to the present invention is that the
wood block is sliced thinly to form a flat thin plate, and this flat thin plate is press-formed into a
vibrating plate shape. . The wood block is sliced thinly to form a flat thin plate, and the flat thin
plate is cut into a flat plate expanded shape, and the cut flat thin plate is formed into a vibrating
plate shape, There are also cases in which both ends of the direction are bonded.
[0007]
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In addition, the wood block is sliced thinly to form a flat thin plate, and the flat thin plate is cut
into a shape similar to the shape of a flat plate expanded, and the cut flat thin plate is similar to
the vibrating plate. After forming both ends in the circumferential direction by bonding in the
shape shown below, this may be pressed into the shape of a diaphragm. Furthermore, the flat
sheet may be boiled with high temperature steam, hot water, or an alkaline solution having a pH
of 10 or more before press forming. Also, the wood block may be cut directly into a diaphragmshaped wood sheet. Furthermore, a plurality of lumber lamellae may be piled up and bonded.
[0008]
[Operation] Since the diaphragm is made of a thin sheet of wood and the wood chips are not
digested with chemicals, the wood fibers are not chemically changed and the wood fibers are not
beaten so that the wood fibers are not damaged. In addition, the timbre can be adjusted by
selecting the type of wood used for the thin sheet of wood constituting the diaphragm or the part
of the wood used for the thin sheet of wood. Furthermore, the wood chips are directly digested or
chemically digested with a chemical to produce a kraft pulp without producing kraft pulp, and a
diaphragm is manufactured by the wood slat. Therefore, the manufacturing process of the
diaphragm can be shortened and the wood chips are not digested with chemicals, so there is no
waste solution from this digestion.
[0009]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present
invention will be described below with reference to the drawings of FIGS. 1 and 2 show a
loudspeaker system, which consists of an enclosure 1 and a circular cone loudspeaker 2.
[0010]
As shown in FIG. 3 and FIG. 4, the cone speaker 2 has a frame 5 having a bowl-like shape
projecting rearward and an opening 4 at the center, and a ring-shaped upper plate 6 fixed to the
rear surface of the frame 5. A ring-shaped magnet 7 fixed to the rear surface of the upper plate
6, and a center pole 11 having the lower plate 8 fixed to the rear surface of the magnet 7 and a
magnetic gap 10 formed between the central pole piece 9 and the upper plate 6; A voice coil 12
inserted into the magnetic gap 10, a voice coil bobbin 13 provided on the inner periphery of the
voice coil 12, a damper 14 provided on the outer periphery of the voice coil bobbin 13, and an
outer diaphragm 15 having a truncated cone shape. The inner diaphragm 16 mounted on the
inner periphery of the outer diaphragm 15 and also serving as a dust cap, and the outer
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periphery of the outer diaphragm 15 And wear is a ring-shaped edge 17, a ring-shaped gasket 18
and the like adhered to the outer peripheral portion of the edge 17.
[0011]
The outer diaphragm 15 is composed of a cylindrical tubular portion 20 at the rear end and a
truncated conical portion 21 on the front side.
Further, the inner diaphragm 16 has a dome shape projecting forward. And in this invention,
although at least one of the outer side diaphragm 15 and the inner side diaphragm 16 consists of
a timber thin plate, as shown in FIG.5 and FIG.6, in the Example, both diaphragms 15 and 16 are
It is supposed to be made of a thin sheet of wood made of the same material such as cherry,
cherry, maple and maple. The diaphragms 15 and 16 may be made of wood thin plates of
different materials.
[0012]
Further, the edge 17 is formed of a material such as acrylic coating cloth, urethane foam,
polyurethane, elastomer, rubber, etc., and has a truncated cone shape and is bonded to the outer
peripheral portion of the truncated cone portion of the outer diaphragm 15. An outer peripheral
side on which a peripheral side frusto-conical portion 23, a semicircular portion 24 projecting
upward in a semicircular shape and positioned in a radial midway portion, having a planar shape
in the front-rear direction and a gasket 18 fixed on the front surface And the flat portion 25 of
the The material of the enclosure 1 is the same as the material of the outer and inner diaphragms
15 and 16.
[0013]
Next, a method of manufacturing the outer and inner diaphragms 15 and 16 will be described by
taking the outer diaphragm 15 as an example. The method of manufacturing the edge 17 will be
described at the same time. There are two types of methods for manufacturing the outer
diaphragm 15, a manufacturing method by press molding and a manufacturing method by
cutting, and the methods will be separately described next.
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[0014]
[Press Forming Method] The wood block is thinly sliced to produce a flat sheet, and then the flat
sheet is cut into an appropriate size. The cut flat sheet is boiled for about 3 minutes in steam at a
temperature of around 180 ° C. and a pressure of 1 atm obtained from a boiler, or in caustic
soda of pH 10 or more, eg pH 13, a temperature of 60 ° C. Boil for about 30 minutes. Water is
sprayed by spraying the boiled flat thin plate at normal temperature. The flat thin plate sprayed
with water is press-molded for about 15 seconds, and the portion excluding the inner and outer
peripheral edges is formed into the shape of the outer diaphragm 15. In this case, as shown in
FIG. 7, the upper and lower molds 29, 30 are heated to about 180 ° C. using upper and lower
molds 29, 30 having nichrome wires 27, 28, respectively. The thin sheet 31 is press-formed.
[0015]
The outer and inner peripheries of the press-formed thin sheet of wood are cut into a
predetermined size and shaped into the shape of the outer diaphragm 15. Abras the front side of
the cut lumber with paper. In order to improve the moisture resistance, the wood thin plate is
dipped in a varnish such as urethane, or the wood thin plate is coated with a varnish to form the
outer diaphragm 15. On the other hand, after the material constituting the edge 17 is pressformed into a predetermined shape by a press die, the inner and outer peripheral edges of the
molded product are cut into a predetermined size to form the edge 17. The outer diaphragm 15
and the edge 17 are bonded by a bonding die.
[0016]
Cutting Method The wood block is cut into the shape of the outer diaphragm 15 by an NC lathe
or the like. Under the present circumstances, since the thickness of the outer side diaphragm 15
is thin, first, after cutting the single-sided shape of the outer side diaphragm 15 to a wood block,
using the jig which has a fixed surface same shape as the said single side of the outer side
diaphragm 15. The cut surface of the wood block is fixed to the fixing surface of the jig by a
method such as adhesion. Next, the other single-sided shape of the outer diaphragm 15 is cut
into a wood block to make the wood block into a thin sheet of wood in the shape of the outer
diaphragm 15. Then, when the cutting is completed, the jig is removed from the thin wood sheet.
After that, the steps of the above-mentioned press molding method are performed.
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[0017]
According to the embodiment configured as described above, since the outer and inner
diaphragms 15 and 16 are not made of kraft paper but made of wood thin plate and wood chips
are not digested with chemicals, the wood fibers are chemically changed In addition, since the
wood fiber is not refined, there is no damage to the wood fiber, and there is no deterioration in
the sound quality due to the chemical change of the wood fiber or the damage to the wood fiber.
In addition, the timbre can be adjusted by selecting the type of wood used for the thin sheet of
wood constituting the outer and inner diaphragms 15 and 16 or the part of the wood used for
the thin sheet of wood, and the timbre of the live instrument It can be brought close to the tone.
[0018]
Furthermore, since a natural wood sheet is used as the outer and inner diaphragms 15 and 16
and a natural wood grain is provided, it is possible to have a high-quality appearance. Also, the
wood chips are directly digested or chemically digested with a chemical to produce a kraft pulp
without making kraft pulp, and the outer and inner diaphragms 15 and 16 are produced by the
wood lamellae. Since the manufacturing is performed, the manufacturing process of the outer
and inner diaphragms 15 and 16 can be shortened and the cost can be reduced, and the wood
chips are not digested with chemicals. There is no fear of pollution.
[0019]
Next, in consideration of the enclosure 1, it is ideal that the enclosure 1 is thoroughly enhanced
in rigidity and not resonated at all, but it is practically impossible. Moreover, the attenuation
response of sound, which is an important element of music, varies depending on the material of
the enclosure 1. As described above, it is a reality that the enclosure 1 itself emits a unique
resonance sound of its material, and the enclosure 1 material is a composite material (for
example, a polyvinyl chloride resin attached to the surface of a particle board, etc. In the case of),
the influence of the surface material is also large.
[0020]
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In the case of a general speaker system, the diaphragm is various, such as kraft paper, carbon,
polypropylene, metal, etc., while the enclosure is generally one in which a vinyl chloride resin is
attached to the surface of a particle board. In such a system, the unique tone of the diaphragm
and the unique tone of the enclosure are different, which is harmful for audio reproduction.
However, in the embodiment, since the material of the enclosure 1 is the same as the material of
the outer and inner diaphragms 15 and 16, the specific tone of the outer and inner diaphragms
15 and 16 and the unique tone of the enclosure 1 are the same. , Preferred on audio playback.
[0021]
In addition, when the material of the enclosure 1 and the outer and inner diaphragms 15 and 16
is different, it is also possible to attach a thin wood plate of the same material as the outer and
inner diaphragms 15 and 16 as a surface material of the enclosure 1. Above, preferred. FIGS. 8
and 9 show a second embodiment of the present invention, wherein a flat thin plate made of
wood is shown in a developed form of the outer diaphragm 15, for example, in FIG. 9 when the
outer diaphragm 15 is manufactured. After cutting into the fan-shaped body 32 as described
above, as shown in FIG. 8, the fan-shaped body 32 is formed into the shape of the outer
diaphragm 15, and the corresponding end portions in the circumferential direction are either one
or both Adhesive applied (acrylic solvent type etc.) Hereinafter, in the case of bonding, an
adhesive of the above-mentioned type or the like is used. Bond by Next, the outer diaphragm 15
is formed by the process of the press forming method.
[0022]
FIG. 10 shows a third embodiment of the present invention, which is a modification of the second
embodiment, and is obtained by cutting a flat plate made of wood into a shape similar to the
shape of the outer diaphragm 15 developed in plan view. Thereafter, the outer diaphragm 15 is
formed into a shape similar to the outer diaphragm 15 and bonded to form the cone 35, and then
the outer diaphragm 15 is manufactured from the cone 35 by the steps of the above-mentioned
press molding method. At the time of manufacture, the upper and lower dies 29, 30 having
nichrome wires 27, 28 as shown in FIG. 10 are used for press molding. According to the third
embodiment, since the wood thin plate having a shape similar to that of the outer diaphragm 15,
ie, the cone body 35, is used at the time of press forming without using a flat thin plate, the
central axial direction length The wood block was sliced thinly without cracking or the like at the
time of manufacturing the long outer diaphragm 15, ie, the outer diaphragm 15 with a large half
apex angle or the outer diaphragm 15 having a complicated shape. The outer diaphragm 15 as
described above can be easily manufactured using a flat thin plate.
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[0023]
11 and 12 show a fourth embodiment of the present invention, in which the outer diaphragm 15
is constituted by a thin wood plate 37 constituting the central portion side and a thin wood plate
38 constituting the outer peripheral portion side. The outer peripheral portion of the wood thin
plate 37 on the central portion side and the inner peripheral portion of the thin wood plate 38 on
the outer peripheral portion are overlapped and bonded. And the material of the wood thin plate
37 at the central portion side and the wood thin plate 38 at the outer peripheral portion side is
different, and for example, the density of one is made larger than the density of the other. The
wood thin plates 37 and 38 are manufactured as in the press forming method, the cutting
method, or the second embodiment, respectively. Bonding of 37 and 38 is performed, and in the
cutting method, bonding of both the wood thin plates 37 and 38 is performed after cutting the
wood thin plates 37 and 38 respectively, and further, the manufacturing method as in the second
embodiment. In this case, bonding of the two wood sheets 37, 38 is performed before or after the
wood sheets 37, 38 are formed.
[0024]
According to the embodiment configured as described above, normally, the outer diaphragm 15
vibrates only at the central portion as the frequency becomes higher. Therefore, when the outer
diaphragm 15 is configured as described above, the higher the frequency becomes, the higher
the frequency becomes. Only the lumber sheet 37 on the central side vibrates. Therefore, by
selecting the material of each lumber sheet 37, 38 appropriately and making the acoustic
characteristics of each lumber sheet 37, 38 different, the sound against the frequency is
generated. Pressure and timbre can be controlled easily and satisfactorily.
[0025]
FIGS. 13 to 16 show a fifth embodiment of the present invention, in which the outer and inner
diaphragms 15 and 16 are overlapped in the vertical direction (in the direction of the central axis
of the outer and inner diaphragms 15 and 16). It is comprised of a plurality of laminated wood
veneers.
In the illustrated example, the outer and inner diaphragms 15 and 16 are configured by the
upper wood thin plates 40 and 41 and the lower wood thin plates 42 and 43, and the wood thin
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plates 40 to 43 adjacent to each other cross vertically It is supposed to be. The material of each
wood sheet 40 to 43 is usually the same but may be different. The outer and inner diaphragms
15 and 16 are manufactured in the same manner as in the fourth embodiment.
[0026]
According to the embodiment configured as described above, the wood thin plates 40 to 43
constituting the outer and inner diaphragms 15 and 16 are respectively plural, and these wood
thin plates 40 to 43 are overlapped and bonded. In addition, since the thin wood plates 40 to 43
vertically adjacent to each other cross at right angles, the warping of each thin wood plate 40 to
43 is suppressed by the thin wood plates 40 to 43 vertically adjacent to each other. Thus, the
warpage of the outer and inner diaphragms 15 and 16 can be prevented. In the fifth
embodiment, the outer and inner diaphragms 15 and 16 are configured by stacking the thin
wood plates 40 to 43, but a diaphragm made of ordinary material, for example, kraft paper may
be used. There are also cases where lumber laminates are stacked and bonded.
[0027]
The above-described embodiments may be combined as appropriate. For example, in the fourth
embodiment, the lumber sheet on the central portion side and the wood grain of the lumber
sheet on the outer peripheral portion side may cross each other in an orthogonal manner.
Furthermore, in the embodiment, the outer diaphragm does not include the edge, but may
include the edge. Although each of the above-described embodiments applies the present
invention to a diaphragm for a cone speaker, the present invention is also applicable to a
diaphragm for a dome speaker having a dome (hemispherical) shape. Next, using the outer
diaphragm of the conventional example and the outer diaphragm of the fifth embodiment of the
present invention, experiments were conducted by configuring a cone speaker. The outer
diaphragm of the conventional example was formed of unbleached kraft paper, the edge was
formed of a cotton cloth, and the cotton cloth was impregnated with phenol and coated with
acrylic.
[0028]
The outer diaphragm has an inner diameter of 20 mm, an outer diameter of 99 mm, a
longitudinal length of 26.5 mm, a length of the tubular portion in the longitudinal direction of 1
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mm, and a radius of curvature of 100 mm in the cross section of the truncated cone. The weight
is 4.0 g. Further, the outer diameter of the edge is 130 mm, the inner diameter of the
semicircular portion is 100 mm, the outer diameter is 120 mm, and the length in the front-rear
direction of the semicircular portion is 5 mm. The outer diaphragm of the fifth embodiment of
the present invention has a two-layer structure of wood thin plate made of case material, and its
dimensions and weight, material of the edge, dimensions and the like are the same as in the prior
art. ing.
[0029]
In the cone speaker, parts other than the outer diaphragm are completely the same. The dotted
line in FIG. 17 shows the experimental result of the sound pressure frequency characteristic of
the conventional example, and the solid line shows the experimental result of the sound pressure
frequency characteristic of the fifth example of the present invention. In the conventional
example, the sound pressure frequency characteristic has a significantly large peak and dip in the
frequency band of 5 KHz or higher, but in the fifth embodiment of the present invention, the
sound pressure frequency characteristic in the above band is flattened compared to the
conventional example. It is done.
[0030]
From the sound pressure frequency characteristics, it can be estimated that the internal loss (tan
δ) of the outer diaphragm of the fifth embodiment of the present invention is significantly larger
than that of the conventional outer diaphragm. Next, the internal loss, Young's modulus, density,
and sound velocity of the outer diaphragms of the conventional example and the fifth
embodiment of the present invention were measured. Table 1 below shows the measurement
results.
[0032]
Referring to Table 1, the outer diaphragm of the fifth embodiment of the present invention has
an internal loss of about 1.27 times and a Young's modulus of about 3.08 times as compared
with the conventional outer diaphragm. , The density is about 1.45 times, the speed of sound is
about 1.46 times. That is, in the fifth embodiment of the present invention, it is superior as the
acoustic diaphragm material in that the Young's modulus is also increased in spite of the increase
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in internal loss as compared with the conventional example. Also, when the sound quality was
evaluated in the conventional example and the fifth example of the present invention, the fifth
example of the present invention has better separation of human voice and musical instrument
sound and separation of musical instrument sounds. The sound loss was good, the reproducibility
in the depth direction was good, the sound spread, and noise was small.
[0033]
As described above in detail, according to the present invention, the diaphragm is not made of
kraft paper but made of wood thin plate, and wood chips are not digested with chemicals, so that
the wood fiber is chemically changed In addition, since the wood fiber is not refined, there is no
damage to the wood fiber, and there is no deterioration in the sound quality due to the chemical
change of the wood fiber or the damage to the wood fiber. Also, by selecting the type of wood to
be used for the thin sheet of wood constituting the diaphragm, or by selecting the part of the
wood to be used for the thin sheet, the timbre can be adjusted and the timbre can be made closer
to the timbre of a live instrument . Furthermore, since a natural wood sheet is used as a
diaphragm and a natural wood grain is provided, it is possible to have a high-class appearance
appearance.
[0034]
Also, the wood fiber is digested or beaten with chemicals to produce a wood sheet directly
without producing kraft pulp, and a diaphragm is manufactured from this wood sheet. Therefore,
the manufacturing process of the diaphragm can be shortened, cost can be reduced, and since
wood chips are not digested with chemicals, there is no possibility of pollution caused by waste
liquid during digestion. Furthermore, usually, the higher the frequency, the diaphragm vibrates
only in the central part. Therefore, if the diaphragm is constituted by a plurality of thin wood
plates arranged in a radial direction as in claim 2, the frequency is high. As it becomes, only the
wood thin sheet at the central part side vibrates, and by selecting the material of each wood thin
sheet appropriately and making the acoustic characteristics of each wood thin sheet different,
sound pressure, timbre, etc. against frequency can be easily made. You can control well.
[0035]
According to the third and fourth aspects of the present invention, a plurality of lumber lamellas
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constituting the diaphragm are provided, and these lumber lamellas are overlapped in the
direction of the central axis of the diaphragm and bonded to each other. When the wood grain of
the lumber thin board is made to cross at right angles, the warp of each lumber thin board will be
suppressed by the adjacent lumber thin board, and the warpage of the diaphragm can be
prevented. According to the sixth aspect of the present invention, it is possible to improve the
sound quality, the timbre, the appearance and the like by laminating the thin lumber on the
diaphragm for cone speaker made of a material other than lumber and bonding. Further,
according to the ninth aspect of the present invention, since the wood thin plate formed into the
shape similar to the diaphragm is used at the time of press forming without using the flat thin
plate, the diaphragm having a long central axial length, That is, during production of a diaphragm
having a large half apex angle or a diaphragm having a complicated shape, no breakage or the
like occurs, and the above-mentioned diaphragm is easily manufactured using a flat thin plate. it
can.
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JP2003116195

JP2004364230