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DESCRIPTION JP2007089222
PROBLEM TO BE SOLVED: To provide a super high frequency reproduction speaker having a
very high high frequency reproduction limit frequency fh and having excellent frequency
characteristics without peak dip. SOLUTION: The speaker of the present invention has a
diaphragm, a voice coil for driving the diaphragm, and a magnetic circuit for forming a magnetic
field intersecting with the voice coil. The junction between the diaphragm and the voice coil has a
shape that does not substantially include a flat portion. Preferably, the diaphragm has a conedome shape, and the half apex angle on the cone side is 10 ° or more, and the half apex angle
on the dome side is 27 ° or more. Preferably, the voice coil is a bobbinless voice coil. [Selected
figure] Figure 2
スピーカー
[0001]
The present invention relates to a speaker. More particularly, the present invention relates to a
super high frequency reproduction speaker having a very high high frequency reproduction limit
frequency fh and excellent frequency characteristics without peak dip.
[0002]
In recent years, digitization of music sources has rapidly progressed in the audio-related industry.
Under such circumstances, the speaker is also required to expand the reproduction frequency
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band. For example, in order to expand the reproduction frequency band in the high frequency
reproduction speaker, it is necessary to further shift the high frequency reproduction limit
frequency fh to a higher frequency side. As means for shifting fh to the high frequency side,
typically, the weight of the vibration system can be reduced, and the rigidity of the diaphragm
can be increased.
[0003]
Here, in the high-frequency reproduction speaker, as a diaphragm material, metal foil such as
beryllium, aluminum, titanium, ceramic, graphite, nonmetallic high elastic material such as
diamond, or the like is used. However, according to such a material, although the rigidity of the
diaphragm can be enhanced, the weight of the vibration system is heavy, and consequently fh
can not be shifted sufficiently to the high frequency side. In addition, since the high rigidity
material has a small internal loss due to vibration, there is a problem that peak dip is easily
generated in the frequency characteristic. Moreover, such high stiffness materials are very
expensive and not practical.
[0004]
On the other hand, in the ultra-high frequency reproduction above fh, the disturbance of the
drive is likely to occur at the junction of the diaphragm and the voice coil, and as a result, the
drive transmission efficiency from the voice coil becomes worse and the sound pressure drops
sharply. Sometimes. In order to avoid such a problem, it is necessary to increase the strength of
the junction between the diaphragm and the voice coil. However, in the conventional speaker, the
strength of the junction is insufficient. This is because the shape has a wide flat portion as shown
in FIG. 8 in order to improve the bonding operability. Furthermore, with materials typically used
for high frequency reproduction speakers, the strength of the junction can not be made
sufficiently high.
[0005]
Further, from the viewpoint of the manufacturing method, in order to shift fh to the high
frequency side, it is important to maintain the center of the voice coil and the application amount
of the adhesive. This is because the disturbance of the driving of the joint portion between the
diaphragm and the voice coil is likely to occur in the ultrahigh frequency band of fh or more.
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[0006]
In the conventional manufacturing method, as shown in FIG. 9, a voice coil holding jig in which a
diaphragm is placed on a diaphragm holding jig, an adhesive is applied to a voice coil joint
portion of the diaphragm, and a voice coil is attached. The diaphragm and the voice coil are
bonded by inserting the above into the diaphragm holding jig.
[0007]
However, in this method, the dimensional difference between the inner diameter D1 of the
diaphragm holding jig and the outer diameter D2 of the voice coil holding jig, and the
dimensional difference between the inner diameter D3 of the voice coil mounting portion of the
voice coil holding jig and the inner diameter of the voice coil. As a result, it becomes difficult to
center the diaphragm and the voice coil.
As a result, when the voice coil is inserted into the magnetic gap of the magnetic circuit, gap
failure may occur. In addition, since the diaphragm is merely placed on the diaphragm holding
jig, the diaphragm may be assembled in an inclined state.
[0008]
Furthermore, in the conventional manufacturing method, when inserting a voice coil holding jig
equipped with a voice coil into the diaphragm holding jig, as shown in FIG. The operation is
performed in such a way that However, according to such an operation, there is a problem that a
voice coil having a particularly narrow width easily falls off the voice coil holding jig. In addition,
according to the conventional method, it is necessary to manufacture a voice coil holding jig
corresponding to each change in height of the voice coil, which is disadvantageous in cost.
[0009]
As described above, there is a strong demand for a high-frequency reproduction speaker that
simultaneously satisfies fh and the problem of peak dip and a simple and inexpensive
manufacturing method thereof. Japanese Utility Model Application Publication No. 58-101598
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Japanese Utility Model Application Publication No. 05-088091
[0010]
The present invention has been made to solve the above-mentioned conventional problems, and
the object of the present invention is to have a very high high-frequency reproduction limit
frequency fh and to have excellent frequency characteristics without peak dip. It is in providing a
super high frequency reproduction speaker.
[0011]
The speaker according to the present invention comprises a diaphragm, a voice coil for driving
the diaphragm, and a magnetic circuit for forming a magnetic field intersecting the voice coil,
and the junction between the diaphragm and the voice coil is substantially Has a shape that does
not include the flat portion.
[0012]
In a preferred embodiment, the diaphragm has a cone-dome shape, and the half apex angle on
the cone side is 10 ° or more, and the half apex angle on the dome side is 27 ° or more.
[0013]
In a preferred embodiment, the vibrating plate is formed of a material selected from the group
consisting of polyetheretherketone, polyetherimide, polyimide and crystalline polystyrene.
[0014]
In a preferred embodiment, the voice coil is a bobbinless voice coil.
[0015]
Hereinafter, the operation of the present invention will be described.
According to the present invention, since the junction of the diaphragm with the voice coil has a
shape that does not substantially include a flat portion, the strength of the junction is improved
and the drive transmission efficiency from the voice coil is improved. The problem that the
pressure characteristics drop sharply is eliminated.
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In addition, since it is not necessary to take measures to increase the thickness of the material to
improve the strength of the diaphragm, there is an advantage that thin materials can be
sufficiently used.
[0016]
In a preferred embodiment, the diaphragm has a cone-dome shape, the half apex angle on the
cone side is 10 ° or more, and the half apex angle on the dome side is 27 ° or more.
By setting the half apex angle in such a range, it is possible to prevent a peak dip in the sound
pressure frequency characteristic and obtain a speaker having a flat characteristic.
[0017]
According to the present invention, by using a diaphragm having a shape in which the junction
with the voice coil does not include a substantially flat portion, it has a very high high-frequency
reproduction limit frequency fh and no peak dip. A very high frequency reproduction speaker
having excellent frequency characteristics can be obtained.
[0018]
Hereinafter, preferred embodiments of the present invention will be described with reference to
the drawings, but the present invention is not limited to these embodiments.
[0019]
FIG. 1 is a schematic cross-sectional view for explaining a speaker according to a preferred
embodiment of the present invention, and FIG. 2 is a schematic cross-sectional view of a
diaphragm and a voice coil included in the speaker of FIG.
As shown in FIG. 1, the speaker 10 has a diaphragm 1, a voice coil 2 for driving the diaphragm 1,
and a magnetic circuit 3 for forming a magnetic field intersecting with the voice coil 2.
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[0020]
The diaphragm 1 has a shape in which a junction with the voice coil 2 does not substantially
include a flat portion.
In the present invention, it is a necessary and sufficient requirement that the joint portion have a
shape substantially free of flat portions.
By having such a shape, the strength of the joint portion is improved, the drive transmission
efficiency from the voice coil is improved, and the problem that the sound pressure characteristic
is sharply reduced is eliminated.
Here, does not include a substantially flat portion means that the width of the joint portion
of the diaphragm 1 is substantially equal to or greater than the diameter of the winding of the
voice coil 2 as shown in FIG. Say.
[0021]
The diaphragm 1 may have any suitable shape as long as it satisfies the requirement that the
joint portion does not substantially include a flat portion, but preferably has a cone-dome shape.
In this case, the absence of a substantially flat portion means that the cone portion and the dome
portion are connected at a practically minimum radius. By connecting in this manner, the width
of the bonding portion of the diaphragm 1 becomes substantially equal to or greater than the
diameter of the winding of the voice coil 2.
[0022]
When the diaphragm 1 has a cone-dome shape, preferably, the half apex angle on the cone side
is 10 ° or more, more preferably 13 ° to 37 °. The half apex angle on the dome side is
preferably 27 ° or more, more preferably 27 ° to 44 °. Here, as shown in FIG. 3, the half
apex angle on the dome side is drawn in the vertical direction from the joint portion with the
voice coil (that is, the apex portion formed by the dome end and the cone end) It is the angle
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defined by the tangent line of the dome line and the dome line. The corn-side half apex angle
is an angle defined by the vertical line and the tangent of the cone end. By setting the half apex
angles on the cone side and the dome side in such a range, it is possible to prevent a peak dip in
the sound pressure frequency characteristic and to obtain a speaker having a flat characteristic.
[0023]
Although any appropriate material can be used as a material which comprises the diaphragm 1,
Specific examples of preferable materials include polyetheretherketone, polyetherimide,
polyimide and crystalline polystyrene. A further preferred material is crystalline polystyrene. It is
because it is inexpensive and superior in strength to metals and inorganic materials.
[0024]
Preferably, the voice coil 2 is directly attached to the diaphragm 1 (that is, the coil is directly
joined to the diaphragm instead of joining the bobbin and the flat joint portion of the diaphragm
as in the prior art). ing). Typically, the voice coil 2 is a bobbinless voice coil. By directly bonding
the voice coil to the diaphragm, the deflection due to the drive becomes very small, and as a
result, the divided vibration of the cone portion and the dome portion is reduced, and the peak
dip is prevented.
[0025]
Hereinafter, a preferable example of the manufacturing method of the speaker of this invention is
demonstrated. In the speaker manufacturing method of the present invention, a voice coil
holding jig 40 as shown in FIG. 4 (a) is used. The voice coil holding jig 40 has a convex portion
41 having a cross sectional shape (horizontal cross sectional shape) corresponding to the cross
sectional shape (horizontal cross sectional shape) of the voice coil and a guide 42. The crosssectional shape of the convex part 41 can take any appropriate shape as long as it corresponds
to the cross-sectional shape of the voice coil. For example, when the cross-sectional shape of the
voice coil is circular, the cross-sectional shape of the convex portion 41 is circular, and when the
cross-sectional shape of the voice coil is elliptical, the cross-sectional shape of the convex portion
41 is elliptical; When the cross-sectional shape of the voice coil is a track shape, the crosssectional shape of the convex portion 41 may be a track shape.
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[0026]
Next, as shown in FIG. 4B, the voice coil 2 is disposed on the voice coil holding jig 40 disposed so
that the convex portion 41 is directed upward. Since the cross-sectional shape of the convex
portion 41 of the voice coil holding jig 40 corresponds to the cross-sectional shape of the voice
coil 2, the voice coil 2 is disposed in conformity with the convex portion 41. By arranging the
voice coil holding jig 40 so that the convex portion 41 is directed upward and by fitting the voice
coil 2 to the convex portion 41, centering of the voice coil becomes accurate and easy. As a
result, it becomes possible to satisfactorily bond the voice coil and the diaphragm having a shape
in which the bonding portion does not substantially include the flat portion as shown in FIG.
[0027]
On the other hand, as shown in FIG. 4C, the diaphragm holding jig attaching member 43 and the
diaphragm holding jig 44 are prepared. The diaphragm holding jig attachment member 43
includes a suction portion 45 and a guide hole 46. The diaphragm holding jig 44 has a shape
corresponding to the shape of the diaphragm, and is adapted to be attached to the diaphragm
holding jig attachment member 43. Furthermore, the diaphragm holding jig 44 is provided with a
suction portion 47 similarly to the diaphragm holding jig attachment member 43. The suction
portion 47 of the diaphragm holding jig 44 communicates with the suction portion 45 of the
diaphragm holding jig mounting member 43 when the diaphragm holding jig 44 and the
diaphragm holding jig mounting member 43 match. Typically, the diaphragm holding jig 44 and
the diaphragm holding jig attachment member 43 can be screwed.
[0028]
Here, as shown in FIG. 4C, the diaphragm 1 molded into a predetermined shape (in the present
embodiment, a cone-dome shape is illustrated) is disposed in the diaphragm holding jig 44, and
the diaphragm 1 Is fitted to the diaphragm holding jig attachment member 43. In such a state,
the diaphragm holding jig 44 and the diaphragm holding jig mounting member 43 are screwed
and suctioned from the outside of the diaphragm holding jig mounting member 43, the
diaphragm 1 and the diaphragm holding jig 44 and the diaphragm Close contact with the holding
jig mounting member 43. Here, an adhesive is applied to the bonding portion of the diaphragm 1
by any appropriate method. Any appropriate adhesive may be used as the adhesive, but typically,
a thermosetting resin adhesive (for example, an epoxy resin adhesive), a photocurable adhesive
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(for example, an epoxy modified acrylate resin adhesive) And UV curable adhesives).
[0029]
Next, as shown in FIG. 4D, with the diaphragm 1 and the diaphragm holding jig 44 and the
diaphragm holding jig mounting member 43 in close contact, the guide hole 46 of the diaphragm
holding jig mounting member 43 is a voice coil The diaphragm 1 and the voice coil 2 are closely
attached to each other through the guide 42 of the holding jig 40. The diaphragm 1 and the
voice coil 2 are firmly bonded by curing the adhesive by any appropriate method depending on
the type of adhesive. Thus, the diaphragm and the voice coil are joined through the guide. Since
the positional relationship between the guide 42 and the projection 41 is fixed, the problem of
centering failure due to dimensional error of each of the assembled speakers is prevented.
Furthermore, since the diaphragm 1 is joined to the voice coil 2 in a state in which the
diaphragm 1 is suctioned in close contact with the diaphragm holding jig 44 (that is, a state in
which the diaphragm 1 and the jig 44 are in close contact with high accuracy), the diaphragm 1
is inclined. There is very little risk of sticking to the voice coil in the situation.
[0030]
In the preferred embodiment, the voice coil holding jig 40 is provided with a height adjustment
unit 47 in the guide 42. The height adjustment unit 47 may be, for example, a ring having a
different thickness. The thickness of the ring may vary corresponding to the height of the voice
coil. By providing such a height adjustment portion, a common voice coil holding jig can be used
even if the dimensions of the voice coil change, which can greatly contribute to the reduction of
the manufacturing cost.
[0031]
The diaphragm and voice coil are then attached to the magnetic circuit, frame, etc. in any suitable
manner to complete the speaker.
[0032]
Example 1 A speaker with a diameter of 27 mm was produced by the following procedure.
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First, a voice coil holding jig provided with a convex portion was disposed such that the convex
portion faced upward, and the bobbinless voice coil was disposed to be fitted to the convex
portion. The voice coil used was a LOK wire having a wire diameter of 0.07 mm. Note that any
appropriate wire type (for example, HAW wire, SVW wire) may be used as the voice coil.
[0033]
On the other hand, a cone-dome shaped diaphragm was formed. The curve of the dome portion
was R5.5, the curve of the cone portion was R4.5, and the voice diameter was 10.44 mm.
Furthermore, the dome portion and the cone portion were connected at a practically minimum
radius, such that the junction between the diaphragm and the voice coil had substantially no flat
portion. In addition, a crystalline polystyrene film was used as a diaphragm material. As a specific
forming procedure, the film is preheated and softened at about 200 ° C. for 5 seconds using a
far-infrared heater, and then gold is used using a mold having a predetermined shape (corn-dome
shape in this embodiment). It press-molded by 85-95 degreeC of mold ¦ die temperature, and 80100 kgf of press pressures.
[0034]
Then, the diaphragm was fixed by suction to the diaphragm holding jig and the diaphragm
holding jig attachment member. Furthermore, using a two-liquid mixing type gear pump
discharger (manufactured by Japan Labor Force Research Co., Ltd.), a two-part epoxy resin
(thermally connected to a connection part between a voice coil and a diaphragm (a connection
part between a cone part and a dome part)) 5 mg of a curable resin adhesive was applied.
Furthermore, by passing the guide hole of the diaphragm holding jig attachment member
through the guide of the voice coil holding jig, the diaphragm coated with the adhesive is brought
into contact with the voice coil and heated at 40 to 50 ° C. for 1 minute. As a result, the
diaphragm and the voice coil were bonded. Finally, the bonded diaphragm and voice coil were
attached to the magnetic circuit, frame, etc. to complete the speaker.
[0035]
The sound pressure frequency characteristics of the obtained speaker were simulated using the
finite element method. The result is shown in FIG. 5 together with the result of Comparative
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Example 1 described later.
[0036]
Comparative Example 1 A speaker was produced in the same manner as in Example 1 except that
the diaphragm had a shape including a wide flat portion as shown in FIG. The same simulation as
in Example 1 was performed on the obtained speaker. The results are shown in FIG.
[0037]
As apparent from FIG. 5, the speaker of Example 1 has a significantly flat sound pressure
frequency characteristic as compared with the speaker of Comparative Example 1, and the
decrease in sound pressure in the superhigh range is also small.
[0038]
Example 2 A speaker was produced in the same manner as in Example 1 except that a diaphragm
having a cone-dome shape as shown in FIG. 6 was formed.
Here, the curve of the dome portion was a composite shape of R1 and R20, the curve of the cone
portion was R4, and the voice diameter was 10.44 mm. The half apex angle on the cone side in
this shape was 13 °, and the half apex angle on the dome side was 44 °. The same simulation
as in Example 1 was performed on the obtained speaker. The results are shown in FIG. 7 together
with the results of Example 3 and Comparative Examples 2 to 4 described later.
[0039]
Example 3 A speaker was produced in the same manner as in Example 2 except that a diaphragm
having a cone side half apex angle of 37 ° and a dome side half apex angle of 42 ° was formed.
Here, the curve of the dome portion was R7.5, and the curve of the cone portion was R4.5. The
same simulation as in Example 2 was performed on the obtained speaker. The results are shown
in FIG.
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[0040]
Comparative Example 2 A speaker was produced in the same manner as in Example 2 except that
a diaphragm having a half apex angle on the cone side of 48 ° and a half apex angle on the
dome side of 48 ° was formed. Here, the curve of the dome portion was R10.5, and the curve of
the cone portion was R4.5. The same simulation as in Example 2 was performed on the obtained
speaker. The results are shown in FIG.
[0041]
Comparative Example 3 A speaker was produced in the same manner as in Example 2 except that
a diaphragm having a half apex angle on the cone side of 35 ° and a half apex angle on the
dome side of 4 ° was formed. Here, the curve of the dome portion was a composite shape of
R10.5 and R4.5, and the curve of the cone portion was R4.5. The same simulation as in Example
2 was performed on the obtained speaker. The results are shown in FIG.
[0042]
Comparative Example 4 A speaker was produced in the same manner as in Example 2 except that
a diaphragm having a cone side half apex angle of 0 ° and a dome side half apex angle of 43 °
was formed. Here, the curve of the dome portion was R20, and the curve of the cone portion was
R4.15. The same simulation as in Example 2 was performed on the obtained speaker. The results
are shown in FIG.
[0043]
As apparent from FIG. 7, the speakers of Example 2 and Example 3 have flat sound pressure
frequency characteristics, and also have less reduction in sound pressure in the ultrahigh range.
On the other hand, in the speaker of Comparative Example 2, the sound pressure drops sharply
in a band larger than 60 kHz. In the speaker of Comparative Example 3, a peak dip is observed at
20 to 40 kHz, and the sound pressure in the band exceeding 70 kHz is reduced. The speaker of
Comparative Example 4 shows a large peak dip at 50 to 60 kHz.
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[0044]
(Example 4) A diffusion metal halide lamp (irradiation intensity: 100 mW / cm 2) was used in an
amount of 10 to 15 using a two-component mixed UV curable adhesive (World Lock No. 836 A /
B, manufactured by Kyoritsu Chemical Sangyo Co., Ltd.) as an adhesive. A speaker was produced
in the same manner as in Example 1 except that the curing was performed by irradiation for a
second.
[0045]
The present invention may be employed in any suitable speaker, and in particular may suitably
be used in tweeters.
[0046]
It is a schematic sectional drawing for demonstrating the speaker by preferable embodiment of
this invention.
It is a schematic sectional drawing of the diaphragm and voice coil which are contained in the
speaker of FIG.
It is a schematic sectional drawing for demonstrating in detail the relationship between the
diaphragm in the speaker of this invention, and a voice coil. (A)-(d) is a schematic diagram for
demonstrating the manufacturing method of the speaker by preferable embodiment of this
invention. It is a graph which shows the simulation result of a sound pressure frequency
characteristic about the speaker of the Example of this invention, and the speaker of a
comparative example. It is a schematic sectional drawing for demonstrating the diaphragm shape
in the speaker of the Example of this invention. It is a graph which shows the simulation result of
a sound pressure frequency characteristic about the speaker of the Example of this invention,
and the speaker of a comparative example. It is a schematic sectional drawing which shows the
diaphragm shape in the conventional speaker. It is the schematic which shows the manufacturing
method of the conventional speaker. It is the schematic which shows the manufacturing method
of the conventional speaker.
Explanation of sign
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[0047]
DESCRIPTION OF SYMBOLS 1 diaphragm 2 voice coil 3 magnetic circuit 10 speaker 40 voice coil
holding jig 43 diaphragm holding jig attachment member 44 diaphragm holding jig
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JP2000175291

JP2000209694

JP2002271890

JP2001268687

JP2003153386

JP2004364230

JP2004129080

JP2001078292

JP2000059883

JP2004343670