JP2000175289

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DESCRIPTION JP2000175289
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
speaker diaphragm used for various audio devices and a speaker using the same.
[0002]
2. Description of the Related Art FIG. 5 is a side sectional view of a conventional speaker. First, a
conventional speaker diaphragm will be described. Conventionally, for the speaker diaphragm
used in the speaker, pulp is formed by heat-pressing after pulping, or injection molding of a resin
or injection-molded styrene or foamed styrene is performed. Various things, such as what
processed and used the board, were used.
[0003]
Further, as shown in FIG. 5, the speaker comprises a magnetic circuit 1 comprising upper and
lower plates and a magnet, in which a magnetic gap 1a is formed, a frame 2 coupled to the
magnetic circuit 1, and edges around the frame 2 A speaker diaphragm 4 is connected via 3 and
a voice coil 5 coupled to the inner periphery of the speaker diaphragm 4 and fitted in the
magnetic gap 1 a of the magnetic circuit 1. Reference numeral 6 denotes a tinsel wire having one
end connected to the coil end of the voice coil 5 and the other end connected to the terminal 7 of
the frame 2 for transmitting an audio signal input from the outside to the coil of the voice coil 5
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is there.
[0004]
However, the above-mentioned speaker diaphragm has the following disadvantages.
[0005]
That is, a speaker diaphragm made of pulp is often used because it is lightweight and has a
relatively high Young's modulus, but there have been problems with environmental
characteristics such as water resistance.
[0006]
In addition, although the speaker diaphragm made of injection-molded resin has good
environmental characteristics such as water resistance, there is a problem that the sound
pressure level is lowered because the specific gravity is heavy.
[0007]
Also, in either case, since the surface thickness is thin, the bending rigidity is weak, and in
general, it has to be a cone shape (substantially conical shape), and the height as a cone shape
limits the thickness reduction as a speaker. There was.
[0008]
If the surface thickness is increased to increase the bending rigidity, the weight of the speaker
diaphragm is increased and the sound pressure level is decreased. If the input is further
increased, the speaker diaphragm causes abnormal resonance and the sound is generated. The
pressure frequency characteristics are disturbed, and the distortion is increased, so that a large
input can not be achieved.
[0009]
Moreover, in the speaker using the speaker diaphragm for expanded styrene, it is possible to
increase the surface thickness because the specific gravity is light, but there is no flatness in the
frequency characteristic because the rigidity of the material itself is low, and a large input The
strain sometimes increases, and the heat resistance of the material is low, which limits the usable
fields.
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[0010]
An object of the present invention is to solve the problems as described above, and to provide a
speaker diaphragm capable of increasing rigidity and increasing input and a speaker that can be
thinned using the same.
[0011]
[Means for Solving the Problems] In order to solve the above-mentioned problems, the speaker
diaphragm of the present invention is formed by foaming of a resin in which a modified
polyphenylene oxide resin filled in a mold and a polystyrene resin are mixed. Since the modified
polyphenylene oxide resin is foamed in the mold, the rigidity and the heat resistance temperature
are improved, and an excellent speaker diaphragm having a small specific gravity can be
obtained.
[0012]
DETAILED DESCRIPTION OF THE INVENTION According to the first aspect of the present
invention, the rigidity and the heat resistance temperature are improved and the specific gravity
is obtained by foaming and forming a resin in which a modified polyphenylene oxide resin and a
polystyrene resin are mixed. It is possible to provide an excellent speaker diaphragm in which a
light one can be obtained and the shape of the diaphragm can be freely set by a mold.
[0013]
According to a second aspect of the present invention, there is provided a speaker diaphragm
according to the first aspect, wherein a central hole into which a voice coil is fitted and a groove
in which a tinsel wire for connecting the voice coil to the outside is disposed. Is formed, and the
outer periphery in the vicinity of this groove is provided with a gate port for resin filling, and the
outer periphery is substantially circular. In general molding at the time of in-mold foaming by
injection, The resin flows well downward by gravity and finally upward.
Therefore, when the gate opening is up, the specific gravity in the opposite direction of the gate
opening is high, and the density near the gate opening is low. Therefore, a groove is provided in
this vicinity to make a tinsel wire. The speaker diaphragm can be set in advance so that the
weight balance of the diaphragm can be obtained in advance, and abnormal resonance occurs
due to the conventional weight balance difference, and as a result, a situation in which large
input is difficult can be avoided. It is possible.
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[0014]
According to a third aspect of the present invention, there is provided a diaphragm for a speaker
according to at least the second aspect, a voice coil fitted and coupled to a central hole of the
diaphragm for the speaker, and a coil of the voice coil at one end. And the other end is provided
in a frame in which the outer periphery of the speaker diaphragm is connected through an edge
via a through hole provided in the groove. The speaker diaphragm according to claim 2 can be
used as a speaker capable of achieving a large input, and the speaker diaphragm can be made
flat. Thus, the speaker can be made thinner and the design freedom of the appearance design can
be improved.
[0015]
Hereinafter, an embodiment of a speaker diaphragm and a speaker using the same according to
the present invention will be described with reference to FIGS. 1 to 4.
[0016]
FIG. 1 is a front view of a flat-plate speaker diaphragm according to an embodiment of the
present invention, FIG. 2 is a sectional view of the same, and FIG. 3 is a half-section of a speaker
using the speaker diaphragm FIG. 4 is a graph showing the same sound pressure frequency
characteristics.
[0017]
First, the speaker diaphragm is mixed with 50% each of modified polyphenylene oxide resin and
polystyrene resin, prefoamed, filled with resin in a mold, and subjected to foam molding using
steam.
After that, annealing was performed in a mold to obtain a flat diaphragm diaphragm 11 shown in
FIGS. 1 and 2.
[0018]
According to the drawing, the speaker diaphragm 11 is formed in a substantially flat plate shape,
and a cylindrical central hole 11a for inserting a voice coil (described later) is provided at the
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center.
11b is a step having a recess depth substantially the same as the thickness of the dust cap
(described later), and the dust cap is fitted.
11c is a groove for positioning and arranging a tinsel wire (described later), and 11d is a hole for
inserting the tinsel wire.
Further, reference numeral 11e denotes a gate port for resin injection at the time of molding, and
is provided on the outer peripheral side in the vicinity of the back surface side of the groove 11c
in which a tinsel wire is disposed.
Physical properties of the speaker diaphragm 11 are shown in Table 1.
In the above embodiment, the expansion ratio is set to 5 times.
In the conventional product, a foamed styrene plate was processed to form a diaphragm for a
speaker.
[0020]
As apparent from (Table 1), the tensile strength of this embodiment is twice that of the
conventional product, and the compression hardness is as high as five times that of the
conventional product.
The heat distortion temperature was also confirmed to be extremely high, 120 ° C., as compared
to 75 ° C. of the conventional product.
[0021]
Using the speaker diaphragm 11 obtained as described above, a 20 cm diameter speaker shown
in FIG. 3 was produced.
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[0022]
In the speaker, the voice coil 18 is fitted in the magnetic gap 17 of the magnetic circuit 16, and
the lower part of the voice coil 18 is supported by the damper 19.
The upper portion of the voice coil 18 is coupled to the inner peripheral portion of the speaker
diaphragm 11, and the outer peripheral portion of the speaker diaphragm 11 is fixed to the
frame 21 via the edge 20.
The lead wire of the voice coil 18 is connected to the tinsel wire 23 at the step 11b in which the
dust cap 22 of the speaker diaphragm 11 is fitted, and after being made to the groove 11c of the
speaker diaphragm 11, through the hole 11d It is coupled to a terminal 24 coupled to the outside
of the frame 21.
A dust cap 22 is fitted in the upper step 11 b of the speaker diaphragm 11.
[0023]
According to the above-described structure, the tinsel wire 23 is not seen from the upper portion
of the speaker diaphragm 11, the structure is apparently completely flat, and the appearance
quality can be improved.
[0024]
The sound pressure frequency characteristics of this speaker are shown in FIG.
From FIG. 4, it is confirmed that the one B according to the present embodiment is flatter and
extends to a higher region as compared with the conventional speaker A using a foamed styrene.
[0025]
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Furthermore, the input-proof test was done using the above-mentioned speaker.
The conventional foamed styrene causes abnormal resonance at about 50 w because the weight
on the side where the tinsel wire 23 is present in the speaker diaphragm 11 causes abnormal
resonance, and the voice coil 18 contacts the magnetic circuit 16 in the magnetic gap 17 In
contrast to the gap failure, it was confirmed that the device of the present embodiment can
withstand a test of about 100 w without causing abnormal resonance even at large input.
Therefore, it has been confirmed that abnormal resonance disappears and large input is possible
even when the speaker is made thinner.
[0026]
In injection molding, the resin flows well downward by gravity at the time of molding and finally
flows upward, so that the gate port is provided relatively upward. The same applies to in-mold
foaming by injection according to the present embodiment, but when the gate port 11e is turned
upward, the specific gravity in the opposite direction of the gate port 11e becomes high, and the
density in the vicinity of the gate port 11e becomes low. In the present embodiment, since the
relationship between the arrangement position of the tinsel wire 23 and the gate opening 11 e is
specified by the groove 11 c as described above, the weight balance of the speaker diaphragm 11
can be obtained by the tinsel wire 23, and abnormal resonance occurs. It is thought that a large
input became possible because it disappeared.
[0027]
In the above embodiment, a resin in which 50% of each of modified polyphenylene oxide resin
and polystyrene resin is mixed is used as a foam material for a speaker diaphragm, but 30% of
modified polyphenylene oxide resin and 70% of polystyrene resin are used. Almost the same
results were obtained except that the heat resistance (heating deformation temperature) was
about 100 ° C.
[0028]
As described above, the speaker diaphragm of the present invention is formed by foaming a
mixture of a modified polyphenylene oxide resin and a polystyrene resin in a mold to improve
rigidity and heat resistance temperature. It is possible to provide an excellent speaker diaphragm
having a light specific gravity and an excellent speaker using the same.
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