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JP2002325294

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Notice
This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
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DESCRIPTION JP2002325294
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
speaker as an electroacoustic transducer having a narrow (long) length and excellent sound
quality.
[0002]
2. Description of the Related Art In recent years, with the spread of high vision, wide vision, etc.,
the screen of a television is becoming generally wide. However, on the other hand, a narrow and
thin television set is desired as a whole for the housing situation in Japan. This is applicable not
only to television but also to general audio components.
[0003]
For example, a speaker unit for television is usually attached to both sides of a cathode ray tube,
which contributes to increasing the width of the television set. Therefore, a narrow speaker unit
having a rectangular shape, an elliptical shape, or the like has conventionally been used for
television. However, as the width of the cathode ray tube is increased, the width of the speaker
unit is required to be further narrowed, and at the same time, the high sound quality of the audio
corresponding to the high image quality of the screen is required.
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1
[0004]
However, in a speaker having a general narrow structure, since a narrow diaphragm is driven by
a voice coil having a major axis and a minor axis, split resonance in the long axis direction is
easily excited. As a result, in the middle-high range, a peak dip occurs on the reproduced sound
pressure frequency characteristic, resulting in deterioration of the sound quality.
[0005]
Hereinafter, the configuration of the above-described conventional narrow-width electro-acoustic
transducer 20 will be described with reference to FIGS.
[0006]
FIGS. 7 (a) and 7 (b) are a front view and a sectional view taken along the line AA of the
electroacoustic transducer 20 having a conventional narrow structure, respectively.
In FIGS. 7 (a) and 7 (b), 21 is a non-axial shape having a major axis and a minor axis when viewed
from the vibration direction, and has a shape continuously curved in a convex-concave shape in
the sound emitting direction. It is a symmetrical diaphragm. An edge 22 is joined to the outer
peripheral portion of the diaphragm 21 and held by the frame 23.
[0007]
At the lower end of the outer peripheral portion of the diaphragm 21, a track type voice coil
bobbin 24 as shown in FIG. 8 is fixed. The voice coil 25 is wound around the outer peripheral
surface of the voice coil bobbin 24. The voice coil bobbin 24 is suspended in a magnetic gap G of
a magnetic circuit to be described later, and generates a driving force by the audio signal current
and the magnetic flux. The frame 23 described above is formed in a box shape, and a part of the
side surface thereof is shaped along the edge 22 direction.
[0008]
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The inner bottom surface of the frame 23 is attached with a magnetic circuit as described later.
The magnetic circuit comprises an iron yoke 26, a magnet 27, and a pole piece 28, and is fixed to
a predetermined position of the frame 23 by a jig not shown. The magnet 27 and the pole piece
28 are provided at a position corresponding to the main vibrating portion of the diaphragm 21.
[0009]
Here, the specific configuration of the diaphragm 21 will be described. As described above, this
diaphragm 21 has a non-axisymmetric shape having a major diameter and a minor diameter and
a shape which is continuously curved in a convex and concave shape in a sound emitting
direction, as viewed from the vibration direction. It is. That is, 29a is a convex portion, and 29b
alternately continuous with this is a concave portion. In addition, the dimension D of the depth
direction to each concave part is formed in substantially the same extent. The diaphragm 21 is
made of a polyimide (PI) film that withstands the heat generation of the voice coil 25 and is
excellent in mechanical characteristics as the diaphragm 21. Reference numeral 29 c denotes a
concave groove provided substantially at the center of the diaphragm 21.
[0010]
By the way, when the diaphragm 21 has a large thickness, it is necessary to increase the weight
and to construct a strong magnetic circuit. Therefore, it is preferable that the thickness be as thin
as possible. However, when the thickness of the conventional diaphragm 21 is reduced, the
strength is reduced, and as shown in FIG. 9, there is a problem that the diaphragm 21 is
depressed inward near the center.
[0011]
This phenomenon causes the voice coil bobbin 24 to be deformed in the same direction, and the
longitudinal central portion of the voice coil bobbin 24 contacts the pole piece 28 due to the
deformation of the diaphragm 21, causing an abnormal sound, as shown in FIG. As described
above, distortion (harmonic distortion such as second-order distortion and third-order distortion)
is generated on the sound pressure frequency characteristics in the middle and high-tone band.
And, as for the deformation, the displacement generated in the direction perpendicular to the
longitudinal direction of the longitudinal central portion of the voice coil bobbin 24 reaches 0.5
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3
mm when 2 volts is input.
[0012]
Therefore, in view of such problems, the present applicant has solved the above problems in
Japanese Patent Application No. 10-192048, and although it has a narrow (long) structure, split
resonance hardly occurs and it is flat. We have proposed an electro-acoustic transducer with
excellent sound quality that is designed to obtain characteristics.
[0013]
However, even with the configuration of such an application, it can not be said that it is sufficient
in terms of manufacturing and the like, and it can not solve the problem that the diaphragm is
recessed inward near the center. It was a thing.
[0014]
Therefore, in order to further improve this point, the present applicant has filed an application in
which the diaphragm and the voice coil bobbin connected to the diaphragm have a novel
configuration, as disclosed in Japanese Patent Application No. 2000-299072 (2000 It is filed as
the application on May 29, hereinafter referred to as the earlier application).
Hereinafter, the configuration of the electroacoustic transducer 10 will be described with
reference to FIGS. 11 to 15.
[0015]
FIGS. 11 (a) and 11 (b) are respectively a front view and a cross-sectional view taken along the
line AA of the narrow-width electro-acoustic transducer 10 according to the above-mentioned
application.
In FIGS. 11 (a) and 11 (b), 1 is a non-axial shape having a major axis and a minor axis when
viewed in the vibration direction, and has a shape continuously curved in a concavo-convex
shape in the sound emitting direction. It is a symmetrical diaphragm. An edge 2 is joined to the
outer peripheral portion of the diaphragm 1 and is held by the frame 3.
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[0016]
A track type voice coil bobbin 4 as shown in FIG. 12 is fixed to the lower end of the outer
peripheral portion of the diaphragm 1. The voice coil 5 is wound around the outer peripheral
surface of the voice coil bobbin 4. The voice coil bobbin 4 is suspended in a magnetic gap G of a
magnetic circuit to be described later, and generates a driving force by an audio signal current
and a magnetic flux. The frame 3 described above is formed in a box shape, and a part of the side
surface thereof is shaped along the edge 2 direction.
[0017]
A magnetic circuit as described later is attached to the inner bottom surface of the frame 3. The
magnetic circuit is composed of a yoke 6 made of iron, a magnet 7 and a pole piece 8, and is
fixed at a predetermined position of the frame 3 by a jig not shown. The magnet 7 and the pole
piece 8 are provided at positions corresponding to the main vibration portion of the diaphragm
1.
[0018]
Here, the specific configuration of the diaphragm 1 will be described. As described above, this
diaphragm 1 has a non-axisymmetric shape having a major diameter and a minor diameter and
having a shape which is continuously curved in a concavo-convex shape in the sound emitting
direction, as viewed from the vibration direction. It is. That is, 11a to 11f are convex portions,
and 12a to 12d alternately connected to the convex portions are concave portions.
[0019]
In addition, the dimension D of the depth direction to each concave part is formed in
substantially the same except the center part. Further, the diaphragm 1 is made of a polyimide
(PI) film that withstands the heat generation of the voice coil 5 and is excellent in mechanical
characteristics as the diaphragm 1.
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5
[0020]
The reference numeral 9 denotes a concave groove provided substantially in the center of the
diaphragm 1 so as to be perpendicular to the longitudinal direction of the vibrating portion. The
dimension F of the concave groove 9 in the depth direction is larger than the depth D to the
concave and is substantially the same as the dimension C of the shoulder 14 of the diaphragm 1
which is a rising portion of the convex It is set to the degree.
[0021]
Next, a specific configuration of the voice coil bobbin 4 fixed to the lower end of the outer
peripheral portion of the diaphragm 1 will be described mainly with reference to FIG. As
apparent from FIG. 12, the voice coil bobbin 4 has a non-axisymmetric shape having a major axis
and a minor axis in plan view seen from the vibration direction of the diaphragm 1, and a part of
the voice coil bobbin 4 is It has straight portions parallel to each other in the major axis direction
of the diaphragm 1.
[0022]
Further, the voice coil bobbin 4 is divided into two parts (41, 42) along the major axis direction
of the diaphragm 1 in the form portion to which the wire is to be wound, and the division parts
are joined in parallel in the minor axis direction. Thus, the beam 13 as a reinforcing portion is
configured.
[0023]
And, according to the narrow-width electro-acoustic transducer 10 as the above-mentioned
application, the second and third order generated at 500 Hz to 1 kHz due to the depression
vibration at the central portion of the diaphragm 1 The effect is that harmonics are greatly
reduced.
[0024]
By the way, when the thickness of the diaphragm 1 is large, it is necessary to increase the weight
and to construct a strong magnetic circuit. Therefore, it is preferable that the thickness be as thin
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6
as possible.
However, in general, when the thickness of the diaphragm 1 is reduced, the strength is reduced,
and it is not possible to suppress the vibration generated in the longitudinal linear portion of the
voice coil bobbin 4 and the vibration of the voice coil bobbin 4 As shown in the frequency
characteristic diagram of FIG. 13, since the side surface of the diaphragm 1 is deformed so as to
be bent and the deformation is lifted by the deformation, since the side surface of the diaphragm
1 is transmitted to the diaphragm 1 connected thereto. It has been the cause of generating
distortion (harmonic distortion such as second-order distortion, third-order distortion, etc.) in the
sound pressure frequency characteristics in the middle to high range.
[0025]
In particular, in this phenomenon, vibration modes of bending waves generated in the diaphragm
shown in FIG. 14 (representative vibrations generated at 5 kHz to 10 kHz are shown as (1) to (d)
as 1⁄4 models) As clearly shown in the graph, the peak frequency is remarkably generated in the
middle to high frequency band 5 kHz to 6 kHz ((a), (b)) and shows a large peak dip as shown on
the frequency characteristic of FIG. It is also a cause of generating distortion (harmonic distortion
such as second-order distortion and third-order distortion) as shown in FIG.
[0026]
Conventionally, in order to solve this problem, as shown in FIG. 15, reinforcing beams 16 to 18
are provided in the short diameter direction of the voice coil bobbin 15 around which the voice
coil 5a is wound. It was prevented by suppressing the vibration which generate | occur |
produces in a longitudinal direction linear part.
FIG. 16 is a side view of an electroacoustic transducer 10 a having such a voice coil bobbin 15.
[0027]
However, according to the electro-acoustic transducer 10a having such a configuration, although
the problems as described above are eliminated, a magnetic circuit is constructed as shown in
FIG. Each part also needs to be divided (A to D) in accordance with the number of reinforcing
beams 16 to 18 described above, resulting in a complicated structure, a decrease in magnetic
flux density, and a complicated manufacturing of parts, etc. In the point of performance stability
and cost, there is room for improvement.
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7
[0028]
In the electro-acoustic transducer 10a of FIG. 16, 1a is a diaphragm, 2a is an edge, 3a is a frame,
5a is a voice coil, 6a is a yoke, 7a to 7d are magnets, 8a to 8d. Is a pole piece, 9a is a concave
groove, 11a1 and 11f1 are convex portions, and 12a1 and 12d1 are concave portions
continuous with the convex portions 11a1 and 11f1 and the like.
[0029]
Therefore, as a result of intensive investigations by the inventors of the present invention, for
example, the cause of the peak on the frequency characteristic shown in the vicinity of 6 kHz in
FIG. 13 is 5.5 kHz and 6.5 kHz in FIG. As apparent from the vibration mode of the bending wave
generated at the center of the diaphragm 1a divided into two blocks by the groove 9a provided at
the center in the longitudinal direction, the central portion (in the longitudinal direction as
viewed from the whole diaphragm It was ascertained that this was caused by pushing up the top
of the diaphragm near the four parts (in the vicinity of the divided parts) because the lateral
amplitude was large.
This phenomenon does not occur at 9 kHz and 10.5 kHz in (c) and (d).
[0030]
And as a result of advancing various experiments as a result of proceeding with various
experiments based on the assumption that such problems may not be due to the shape of the
curved portion continuously formed in an uneven shape in the direction of radiating the sound of
the diaphragm. The planar shape has a major axis and a minor axis and is formed substantially in
a track shape, and a groove is formed in a strip shape along the track, and is continuously curved
in a convex and concave shape in a sound emitting direction. It has been found that employing a
non-axisymmetric diaphragm configuration in which the groove portion is provided in the
substantially central portion orthogonal to the longitudinal direction of the vibrating portion as
connected to the above has brought about a considerable result.
[0031]
Further, as a configuration of the voice coil bobbin, a form portion to which a wire is to be wound
is divided into two along the longitudinal direction of the diaphragm, and a groove portion
provided in a substantially central portion of the diaphragm in a state where the divided portions
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8
are joined. What has been connected to has also been found to bring considerable success.
[0032]
Furthermore, since the transverse amplitude near the portion where the longitudinal direction is
divided into four is large when viewed from the whole diaphragm, which is the direct cause of
the above-mentioned problems, the top of the diaphragm near the same portion is pushed up
Regarding the points to be added, a reinforcing agent is filled in a plurality of places of the
groove formed in a strip along the track with a width equivalent to one of the curved parts
formed continuously in the form of irregularities in the direction of emitting the sound. It has
been found that this will also produce considerable success.
[0033]
Then, an electroacoustic transducer that comprehensively takes into consideration such a
specific diaphragm configuration, voice coil configuration, reinforcing agent filling location, etc.
is manufactured, and the above-described problems are realized by conducting verification in
various experiments. It is clear that it is possible to obtain an electroacoustic transducer that has
been completely solved, and so a new proposal is made here.
[0034]
Hereinafter, it will be described with reference to FIGS. 17 to 20 that the above-described
diaphragm configuration, voice coil configuration, and filling place of the reinforcing agent are
important.
[0035]
FIG. 17 shows that in the specific diaphragm configuration described above, when viewed from
the entire diaphragm, the portion filled with the reinforcing agent is different from the vicinity of
the portion where the longitudinal direction is divided into four, specifically, in the sound
radiation direction. It is a perspective view which shows the example at the time of filling with
the comparable width | variety in the both sides position corresponding to the recessed part
among the curved parts continuously formed unevenly.
[0036]
FIG. 18 shows that in the specific diaphragm configuration described above, when viewed from
the entire diaphragm, the portion where the reinforcing agent is filled is different from the
vicinity of the portion where the longitudinal direction is divided into four, specifically, both ends
in the diaphragm longitudinal direction It is a perspective view which shows the example at the
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9
time of filling to a part.
[0037]
FIG. 19 is a frequency characteristic diagram in the configuration of FIG. 17 described above. As
apparent from FIG. 19, when the reinforcing agent is filled in the position as shown in FIG. It can
be seen that the effect of filling the reinforcing agent such as the reduction of the wave distortion
is small.
[0038]
FIG. 20 is a frequency characteristic diagram in the configuration of FIG. 18 described above. As
apparent from FIG. 20, when the reinforcing agent is filled in the position as shown in FIG. It can
also be seen that the effect of filling the reinforcing agent, such as less reduction of wave
distortion, is not obtained.
[0039]
From the above description, it is clear that the diaphragm configuration, the voice coil
configuration, and the filling point of the reinforcing agent are important, and the present
invention aims to provide an electroacoustic transducer having such a specific configuration. It is
a thing.
[0040]
SUMMARY OF THE INVENTION The present invention has been made to achieve the above
object, and a planar shape viewed from the direction of vibration is formed into a substantially
track shape having a major axis and a minor axis. The groove 30 is formed in a strip shape along
the track, and is continuously curved in a concavo-convex shape in the sound emitting direction,
and is connected to the groove 30 at a substantially central portion orthogonal to the
longitudinal direction of the vibrating portion. The non-axisymmetric diaphragm 1 provided with
the narrow groove portion 9 and the outer peripheral portion of the groove portion 30 formed in
a band shape along the track are formed in a band shape, and the band inner peripheral portion
is The edge 2 which is connected to the outer periphery and holds the diaphragm 1 in a vibrating
manner, and the foam portion to which a wire is to be wound is divided into two along the
longitudinal direction of the diaphragm 1. In the narrow groove portion 9 provided in the
approximate center of the diaphragm 1 in the state A voice coil bobbin 4 connected, a voice coil
5 wound around the outer peripheral surface of the voice coil bobbin 4, magnetic circuits 6, 7
and 8 for giving a magnetic flux for vibration to the voice coil 5, and an outer periphery of the
edge 2 Section, and a frame 3 for holding the magnetic circuits 6, 7, 8 and continuously in the
form of irregularities in the direction of emitting the sound at a plurality of locations of the
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groove section 30 formed in a strip shape along the track It is characterized in that the
reinforcing agent 31 is filled in the same width as one of the formed curved portions.
[0041]
BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present
invention will be described below with reference to the attached drawings.
The embodiments described below are preferable specific examples of the present invention, and
therefore, various technically preferable limitations are given, but the scope of the present
invention particularly limits the present invention in the following description. As long as there is
no statement of the effect, it is not limited to these modes.
[0042]
FIG. 1 shows a preferred embodiment of the electroacoustic transducer according to the present
invention, wherein (a) is a plan view, (b) is a sectional view taken along the line AA and (c) is a
sectional view taken along the line BB FIG. 2 shows an uneven curved portion provided in the
direction of emitting the sound at a plurality of locations of the groove formed on the outer
peripheral portion of the diaphragm constituting the main portion of the electroacoustic
transducer of FIG. Fig. 3 is a perspective view of a voice coil bobbin around which a voice coil is
wound, and Fig. 4 is a reinforcement in the longitudinal direction of the diaphragm. 5 is a crosssectional view of a portion filled with a reinforcing agent in the longitudinal direction of the
diaphragm after bonding with a voice coil bobbin, and FIG. 6 is an electroacoustic transducer
according to this embodiment. Frequency characteristic of the
The basic configuration of this embodiment is substantially the same as that of the narrow-width
electro-acoustic transducer 10 according to the above-mentioned application, but there are some
differences.
[0043]
First, with reference to FIG. 1 and FIG. 2, the specific structure of the diaphragm 1 which
comprises the electroacoustic transducer 50 which becomes a present Example is demonstrated.
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11
[0044]
1 (a) to 1 (c) are a front view, a cross-sectional view taken along the line AA and a cross-sectional
view taken along the line BB of the narrow width electroacoustic transducer 50 according to this
embodiment, and FIG. A plurality of groove portions formed on the outer peripheral portion of
the diaphragm constituting the main portion of the electroacoustic transducer have a width
equivalent to one of the concave and convex curved portions provided in the direction of
emitting the sound. It is a perspective view filled with reinforcing agents, such as adhesives.
[0045]
In FIGS. 1 (a) and 1 (b), 1 has a shape having a major axis and a minor axis, and a shape which is
continuously curved in a convex-concave shape in the direction of sound emission. It is a nonaxisymmetric diaphragm having a groove 30 formed in a strip shape along the outer periphery.
An edge 2 is joined to the outer peripheral portion of the diaphragm 1 and is held by the frame
3.
[0046]
A track type voice coil bobbin 4 as shown in FIG. 3 is fixed to the lower end of the outer
peripheral portion of the diaphragm 1.
The voice coil 5 is wound around the outer peripheral surface of the voice coil bobbin 4.
The voice coil bobbin 4 is suspended in a magnetic gap G of a magnetic circuit to be described
later, and generates a driving force by an audio signal current and a magnetic flux.
The frame 3 described above is formed in a box shape, and a part of the side surface thereof is
shaped along the edge 2 direction.
[0047]
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12
A magnetic circuit as described later is attached to the inner bottom surface of the frame 3.
The magnetic circuit is composed of a yoke 6 made of iron, a magnet 7 and a pole piece 8, and is
fixed at a predetermined position of the frame 3 by a jig not shown.
The magnet 7 and the pole piece 8 are provided at positions corresponding to the main vibration
portion of the diaphragm 1.
[0048]
Here, the specific configuration of the diaphragm 1 will be described.
As described above, the diaphragm 1 is formed substantially in the shape of a track having a
major axis and a minor axis as viewed in the vibration direction, and the groove 30 is provided
along the track and emits sound. It has a non-axisymmetric shape in which a narrow groove 9 is
provided at a substantially central portion orthogonal to the longitudinal direction of the
vibrating portion so as to be continuously curved in a concavo-convex shape in a direction and
connected to the groove 30.
That is, 11a, 11b, 11c, 11d, 11e, and 11f are convex portions, and 12a, 12b, 12c, and 12d
alternately connected to the convex portions are concave portions.
[0049]
Reference numeral 31 denotes a reinforcing agent filled in the groove 30 with a width of the
same extent as that of one of the concave and convex curved portions, and a flexible plastic, for
example, a chloroprene-based adhesive A mixture of a plasticizer in 1: 9 to 2: 8 is preferable.
The amount of the reinforcing agent 31 filled in the groove 30 is approximately the same height
as the surface of the edge 2 as apparent from FIGS. 4 and 5 described later, that is, the degree to
12-05-2019
13
which the groove 30 is buried is It is optimal.
If the amount is smaller than this, the peak on the frequency characteristic does not become flat,
and if it exceeds the extent that the above-mentioned groove 30 is buried, the frequency
characteristic becomes flat as shown in FIG. However, this is not preferable because the sound
pressure of the high-pitched sound decreases.
[0050]
Further, the dimension D in the depth direction to each concave portion is formed to be
substantially the same except for the central portion.
Further, the diaphragm 1 is made of a polyimide (PI) film that withstands the heat generation of
the voice coil 5 and is excellent in mechanical characteristics as the diaphragm 1.
[0051]
A thin groove 9 is provided in the substantially central portion of the diaphragm 1 so as to be
orthogonal to the longitudinal direction of the vibrating portion.
The dimension F in the depth direction of the narrow groove portion 9 is larger than the depth D
to the concave portion, and is substantially the same as the dimension C of the shoulder portion
14 of the diaphragm 1 which is the rising portion of the convex portion. It is set to the degree.
[0052]
Reference numeral 30 denotes a groove formed in a band along the outer peripheral portion
(track) of the diaphragm 1 as described above.
Further, as apparent from FIGS. 4 and 5 described later, the depth of the groove 30 is shallower
than the position of the voice coil 5 wound around the outer peripheral surface of the voice coil
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14
bobbin 4 (close to the diaphragm 1 side The position) and the width thereof are set to be as large
as a magnetic gap and to such a size that the magnetic circuit portion can not be contacted by
the amplitude of the vibration system. That is, the surface accuracy of the groove 30 is secured
by a molding die.
[0053]
Next, the specific configuration of the track type voice coil bobbin 4 fixed to the lower end of the
outer peripheral portion of the diaphragm 1 will be described with reference to FIGS. As apparent
from FIG. 3, the voice coil bobbin 4 has a non-axisymmetric shape having a major axis and a
minor axis in plan view seen from the vibration direction of the diaphragm 1, and a part of the
voice coil bobbin 4 is It has straight portions parallel to each other in the major axis direction of
the diaphragm 1. Reference numeral 5 denotes a voice coil wound around the voice coil bobbin
4.
[0054]
Further, the voice coil bobbin 4 is divided into two parts (41, 42) along the major axis direction
of the diaphragm 1 in the form portion to which the wire is to be wound, and the division parts
are joined in parallel in the minor axis direction. Thus, the beam 13 as a reinforcing portion is
configured. Reference numeral 15 denotes a band made of kraft paper wound around the outer
peripheral surface of the voice coil bobbin 4 and used as reinforcing paper.
[0055]
In the voice coil bobbin 4 configured in this manner, as described above, the dimension F of the
groove 9 in the depth direction is larger than the depth D to the concave portion, and the
diaphragm 1 is a rising portion of the convex portion. Since the dimension C of the shoulder
portion 14 is set to be substantially the same as that of the shoulder portion 14, as shown in FIG.
1 (b), FIG. 4 and FIG. It can be directly fixed without any problem below the narrow groove 9
which is a regular position.
[0056]
Next, the operation of the electroacoustic transducer 50 configured as described above will be
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15
described.
In the above configuration, when a magnetic field is generated around the coil 4 by the magnet 7
and a drive current flows through the coil 5 wound around the coil 4, an electromagnetic force
corresponding to the drive current is transmitted to the coil 4. The diaphragm 1 vibrates mainly
by the main vibration portion 1a by the electromagnetic force.
[0057]
During this vibration, the vicinity of the narrow groove 9 which is the central portion in the
longitudinal direction of the diaphragm 1 is supported by the beam 13 as a reinforcing portion. It
does not occur, that is, divided vibration is prevented.
[0058]
Further, as described above, the groove 30 which is continuous with the narrow groove 9 and
provided around the vibrating portion has its surface accuracy ensured, so that the driving force
is accurately transmitted.
[0059]
Further, the upper surface of the diaphragm 1 is a substantially semi-cylindrical surface 11 a
having a shape projecting outward (in the direction of emitting sound) and a substantially semicylindrical surface 12 a etc. Are alternately arranged in the longitudinal direction, the occurrence
of the vibration component of this portion can be prevented in a complementary manner.
[0060]
FIG. 6 shows that, in the electro-acoustic transducer 50 according to the present embodiment, in
the groove portion 30 formed in a strip shape along the outer peripheral portion of the
diaphragm 1, the diaphragm 1 continues in a concavo-convex shape in the direction of radiating
the sound. Sound pressure frequency characteristics and harmonics in the case where the
reinforcing agent 31 is filled in four portions on both sides of the protrusion, for example, with a
width equivalent to one of the curved portions among the curved portions formed as described
above FIG. 22 is a frequency characteristic diagram showing a relationship between sound
pressure frequency characteristics and harmonic distortion when the above-mentioned groove
30 is not filled with a reinforcing agent.
[0061]
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16
In the present embodiment, although an example in which the reinforcing agent is filled in four
places on both sides of the convex part for reasons of molding is described, if the concavities and
convexities are molded in the opposite direction, the four sides of the concave part are
Reinforcing agents are filled in places.
[0062]
As is apparent from these two figures, in the groove portion 30 provided around the diaphragm
1, for example, a protrusion of a curved portion continuously formed in an uneven shape in a
direction of radiating the sound of the diaphragm 1. In the case where the reinforcing agent 31 is
filled in four places on both sides of the portion with the same width as one of the curved
portions, compared to the case where the reinforcing agent is not filled in the groove 30
described above, Demonstrated that the level of the peak on the sound pressure frequency
characteristics that occurred around 5 KHz to 6 KHz decreased due to vibration, and that the
second and third harmonic distortions on the frequency characteristics are greatly reduced The
superiority of this embodiment can be seen at a glance.
[0063]
As described above, according to the present invention, the planar shape viewed from the
vibration direction has a major axis and a minor axis and is formed substantially in a track shape,
and a groove is provided in a strip shape along the track. And a non-axisymmetric vibration in
which a narrow groove is provided at a substantially central portion orthogonal to the
longitudinal direction of the vibrating portion so as to be continuously curved in a concavoconvex shape in a sound radiating direction and connected to the groove. The strip is formed in a
strip along the outer periphery of the plate and the groove formed in a strip along the track, and
the strip inner periphery is connected to the outer periphery of the groove to hold the diaphragm
in a vibrating manner. The edge and the form portion to which the wire is to be applied are
divided into two along the longitudinal direction of the diaphragm, and in a state in which the
divided portions are joined, they are connected to the narrow groove portion provided
substantially at the center of the diaphragm. Voice coil bobbin and outer peripheral surface of
the voice coil bobbin A voice coil to be wound, a magnetic circuit for applying a magnetic flux for
vibration to the voice coil, an outer peripheral portion of the edge, and a frame for holding the
magnetic circuit, and formed in a strip along the track By filling a reinforcing agent with a width
equivalent to one of the curved portions continuously formed in an uneven shape in the direction
of emitting the sound at a plurality of locations in the groove, an abnormal vibration in the
longitudinal direction generated by natural vibration is generated. There is an effect that sound
waves can be suppressed and distortion-free can be realized.
[0064]
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17
Brief description of the drawings
[0065]
1 is an explanatory view showing an embodiment of the electro-acoustic transducer according to
the present invention.
[0066]
2 is a perspective view showing a state in which a reinforcing agent is filled in the diaphragm
that constitutes the main part of the electroacoustic transducer of FIG.
[0067]
3 is a perspective view of a voice coil bobbin around which a voice coil constituting the main part
of the electroacoustic transducer of FIG. 1 is wound.
[0068]
4 is a cross-sectional view of the longitudinal direction central portion of the diaphragm in FIG.
[0069]
5 is a cross-sectional view of the longitudinal center of the diaphragm after bonding with the
voice coil bobbin in FIG.
[0070]
6 is a frequency characteristic diagram of the electro-acoustic transducer according to the
present invention.
[0071]
7 is an explanatory view of a conventional electro-acoustic transducer.
[0072]
FIG. 8 is a perspective view of a voice coil bobbin around which a voice coil constituting the main
part of the conventional electroacoustic transducer is wound.
12-05-2019
18
[0073]
9 is an explanatory view of the depression vibration of the central portion of the diaphragm used
in the conventional electro-acoustic transducer.
[0074]
10 is a frequency characteristic diagram of a conventional electro-acoustic transducer.
[0075]
11 is an explanatory view of an electro-acoustic transducer as a prior application.
[0076]
12 is a perspective view of a voice coil bobbin around which a voice coil constituting the main
part of the electro-acoustic transducer shown in FIG. 11 is wound.
[0077]
13 is a frequency characteristic diagram of the electro-acoustic transducer as the prior
application.
[0078]
14 is an explanatory view showing the vibration mode of the bending wave generated in the
diaphragm used in the electro-acoustic transducer as the prior application.
[0079]
FIG. 15 is a perspective view of another voice coil bobbin around which a voice coil used in the
conventional electroacoustic transducer is wound.
[0080]
16 is another explanatory view of a conventional electro-acoustic transducer.
[0081]
17 is a perspective view showing another state in which the diaphragm constituting the main
part of the electroacoustic transducer in FIG. 1 is filled with a reinforcing agent.
12-05-2019
19
[0082]
18 is a perspective view showing still another state in which the diaphragm constituting the main
part of the electroacoustic transducer in FIG. 1 is filled with a reinforcing agent.
[0083]
19 is a frequency characteristic diagram of the electro-acoustic transducer in FIG.
[0084]
20 is a frequency characteristic diagram of the electro-acoustic transducer in FIG.
[0085]
21 is a frequency characteristic diagram when the amount of reinforcing agent filled in the
groove portion of the diaphragm is more than a predetermined amount.
[0086]
FIG. 22 is a frequency characteristic diagram in the case where no reinforcing agent is used in
the electroacoustic transducer of FIG.
[0087]
Explanation of sign
[0088]
Reference Signs List 1, 21 diaphragm 2, 22 edge 2a outer peripheral portion 3, 23 frame 4, 15
voice coil bobbin 5, 25 voice coil 6, 26 yoke 7, 27 magnet 8, 28 pole piece 9 narrow groove
portion 10, 20, 50 electroacoustic conversion 11a to 11f, 29a convex portion 12a to 12d, 29b
concave portion 13 beam 14 shoulder portion 16 to 18 reinforcing beam 29c concave groove
portion
12-05-2019
20
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