JPH06261392

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DESCRIPTION JPH06261392
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention improves
performance by using an improved material suitable for forming a vibration system component
such as a normal diaphragm used for a speaker, or a diaphragm of a composite structure, or a
dust cap. Related to the above-described vibration system parts.
[0002]
2. Description of the Related Art Conventionally, in the case of a diaphragm, for example, in the
case of a diaphragm, vibration of a composite structure comprising a skin such as a honeycomb
plate and a core is a vibration material of a loudspeaker. Even in the case of plates, in order to
make the frequency characteristics of the reproduction band wide and flat, high elasticity to
increase the split vibration frequency and high internal loss to suppress split resonance in the
high region Although various materials are conventionally used, it is required to have both
materials, but there are few materials that achieve both of these properties in a balanced manner,
and pulp that is relatively close to the required properties and can be mass-produced. The
diaphragm using is often used.
[0003]
However, with diaphragms using pulp, the elastic modulus is often insufficient. Especially for the
diaphragms of high-pitched speakers, a single metal or a surface-treated metal diaphragm is
used, but the internal loss is low. In particular, there is a drawback that the frequency
characteristics are significantly uneven, which often gives a sense of discomfort to the auditory
sense.
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[0004]
In order to eliminate this defect, a diaphragm using a resin film is used.
When heat resistance is required and high elasticity is required, polyimide etc. are used, but
moldability is difficult and internal loss is also small, so heat resistance of about 100 ° C. is
sufficient. A diaphragm using a polyester resin film is often used.
[0005]
Also, in a cone-shaped speaker, the dust cap attached to the base of the cone-shaped diaphragm
is used together with the original dustproof function to prevent foreign matter from entering the
magnetic gap and causing malfunction. It also has the effect of preventing vibration of the
diaphragm and absorbing vibration energy when abnormal vibration occurs, suppressing
abnormal vibration and improving frequency characteristics, so that it has high rigidity just like
the diaphragm. A high internal loss is required, and a material similar to the diaphragm is used.
[0006]
PROBLEM TO BE SOLVED BY THE INVENTION A diaphragm and a dust cap using a conventional
polyester resin film having such a structure are inexpensive but have low heat resistance and
further lack of adhesion, so the price is low. There is a problem to be solved that it is difficult to
obtain a highly reliable product by improving heat resistance and adhesion under the constraint
of
[0007]
Therefore, the present invention solves the disadvantages of the prior art and uses a polyester
polycarbonate resin film instead of a polyester resin to provide a dome diaphragm, a dust cap
and a honeycomb structure vibration which are both excellent in heat resistance and
adhesiveness at low cost. It aims at providing vibration system parts, such as a board.
[0008]
A vibration system component according to the present invention for achieving the above object
will be described with reference to FIGS. 1 to 5 showing an embodiment. The first invention
relates to a polyester polycarbonate resin film It is a shaped diaphragm characterized by being
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obtained by molding.
[0009]
A second invention is a dust cap obtained by molding a polyester polycarbonate resin film.
[0010]
A third invention is a honeycomb diaphragm characterized in that a film made of polyester
polycarbonate resin is used as a skin material.
[0011]
In the vibration system part having such a constitution, the polyester polycarbonate resin as the
material is made of a copolymer of polyester resin and polycarbonate resin.
That is, as is well known, polyester resins have a low heat distortion temperature and good
solvent resistance but poor adhesion.
On the other hand, polycarbonate resins have high heat distortion temperatures and poor solvent
resistance but good adhesion.
Therefore, when it becomes a copolymer, the properties of both resins are taken into
consideration and the defects are complemented to improve the heat resistance (heat distortion
temperature), solvent resistance and adhesion.
[0012]
The heat resistance of the polyester polycarbonate resin of the present invention is as high as
about 135 ° C. as compared with the conventional polyester resin of about 70 ° C. as shown in
Table 1 in consideration of the heat resistance of the polycarbonate resin.
[0013]
Regarding adhesion, for the 1-inch wide sample, the experimental results of observing the
adhesion to the canvas using the rubber-based adhesive most commonly used for speaker
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assembly show that the conventional polyester resin is as shown in Table 2. While polyester
polycarbonate resin is 1.5 (Kgf), it is about 3 times as opposed to about 0.5 (Kgf).
[0014]
As for solvent resistance, according to the observation result when swelling state to ethyl acetate
and toluene is compared with polycarbonate resin, as shown in Table 3, polycarbonate resin
swells completely in 1 minute after immersion, while polyester polycarbonate resin Does not
swell after 10 minutes.
[0015]
Also, among the physical properties of the material, as shown in Table 4, Young's modulus
(related to rigidity) and tan δ (internal loss) are larger than polycarbonate which is one of the
constituent components, particularly for flattening the frequency characteristics of the speaker.
The contributing tan δ is much larger and has a value close to that of the other component,
polyester.
[0016]
Therefore, as shown in FIG. 1 to FIG. 3, when incorporated into a speaker as a dome-shaped
diaphragm or a flat plate diaphragm of a honeycomb structure, it has adhesion, heat resistance,
and similar characteristics as a speaker using a conventional polyester resin film. Since the
solvent resistance is excellent, improvement in performance and reliability is expected as
compared with the conventional example.
[0017]
As described above, the lack of heat resistance and adhesion of the polyester resin is
compensated by the polycarbonate resin, so that the material itself is inexpensive as compared
with conventionally used polyimide etc., and the molding is easy, and the adhesion and resistance
Since the solvent property is excellent, the productivity in the speaker manufacturing process is
good.
Furthermore, it has the same Young's modulus and internal loss as a conventional polyester resin
as a diaphragm, and its frequency characteristics are good.
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Therefore, it is possible to inexpensively provide a speaker excellent in both reliability and
performance without significantly increasing the cost of parts.
[0018]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT To describe the embodiment of the
present invention in detail, polyester polycarbonate resin obtained by reacting bisphenol A and
terephthalic acid with phosgene is rolled to a film of the required thickness corresponding to
each part of the vibration system. A polyester polycarbonate resin film was used as a constituent
material of vibration system parts.
[0019]
In the dome-shaped diaphragm of the first invention, after heating a polyester polycarbonate
resin film having a thickness of 50 μm by about 200 ° C. with a heater, it is press-formed with
a 30 mm diameter mold of the dome portion heated to about 160 ° C. Thus, a dome-shaped
diaphragm is obtained, and as shown in FIG. 1, a dome-shaped speaker of a known structure
comprising the dome-shaped diaphragm 1, the voice coil 2, the magnetic circuit 3 and the frame
4 is shown.
In addition, a dome-shaped diaphragm of the same size was manufactured from polyester film,
and a speaker having the same structure was assembled as a conventional example for
comparison.
[0020]
In the dust cap of the second invention, a polyester polycarbonate resin film having a thickness
of 100 μm is press-formed under the same conditions as the above-mentioned dome-shaped
diaphragm to obtain a spherical dust cap 5 whose cross section is shown in FIG.
The dust cap 5 is bonded to the vicinity of the base of the cone-shaped diaphragm 7 having a
known structure by its peripheral portion 5a.
[0021]
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In the honeycomb diaphragm 6 of the third invention of which the cross section is shown in FIG.
3, a polyester polycarbonate resin film having a thickness of 100 μm is cut into 60 mm × 60
mm to form a skin 6a. The cell size is 3 mm and the thickness is 2.8 mm. It bonded to the both
surfaces of the aluminum honeycomb core 6b, and obtained the target plate-shaped honeycomb
diaphragm 6 was obtained.
The voice coil 2 is adhered to the back surface of the honeycomb diaphragm 6, and combined
with the magnetic circuit 3 and the frame 4 to form a flat speaker having a known structure
whose schematic cross section is shown in FIG.
Further, as to a flat plate speaker using the honeycomb diaphragm of the third aspect of the
present invention, a honeycomb diaphragm made of polyester as a skin material was
manufactured, and speakers of the same structure were assembled and used as a conventional
example for comparison.
[0022]
As mentioned above, although the vibration system parts of the speaker concerning the present
invention were explained in full detail based on the example considered to be representative, the
embodiment of the vibration system parts by the present invention is not limited to the structure
of the above-mentioned example, For example, although the detailed description is not given, the
diaphragm of the first invention may be in the form of a cone as shown in FIG. As long as it
exhibits an action and has the effects described below, it can be appropriately modified and
implemented.
[0023]
The vibration system component for a speaker according to the present invention has the
following effects.
[0024]
(1)
The polyester polycarbonate resin which is the material is as high as about 135 ° C. and about
200% as compared with the conventional polyester resin of about 70 ° C. as shown in Table 1
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above.
Therefore, molding is easy as compared with a polyimide resin film.
[0025]
(2)
Adhesion is improved as much as polycarbonate resin as compared with polyester resin as shown
in Table 2 and solvent resistance as shown in Table 3, respectively.
Therefore, in combination with the effect of the above (1), the productivity in the speaker
manufacturing process is good and the reliability of the product is improved.
[0026]
(3)As shown in Table 4, the stiffness and internal loss of the material are close to those of the
polyester resin.
[0027]
(4)
It is inexpensive compared to the polyimide resin film.
Therefore, the manufacturing cost can be kept low.
[0028]
With the above advantages, the present invention has the effect of being able to provide a
speaker excellent in both reliability and performance at low cost without significantly increasing
the price of parts.
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