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JP2008085577

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This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
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DESCRIPTION JP2008085577
An object of the present invention is to realize a speaker device with high output by securing a
large vibration stroke of a voice coil. It is relatively easy to optimize the magnetic flux density in
the magnetic gap. An inner magnet (11), an outer magnet (12), a first support surface (13a) and a
second support surface (13b) and a magnetic gap (10G) behind the first support surface (13a)
and the second support surface (13b). And an inner plate 14 and an outer plate 15. The first
support surface 13a and the second support surface 13b of the yoke 13 correspond to the front
surface 11a of the inner magnet 11 and the outer magnet. The front surfaces 12 a of the 12 are
set to be on the same plane, and the magnetic gaps 10 G are formed immediately before the front
surfaces of the inner magnet 11 and the outer magnet 12. [Selected figure] Figure 2
Speaker magnetic circuit and speaker device
[0001]
The present invention relates to a speaker magnetic circuit and a speaker device.
[0002]
The speaker device converts an electrical signal into an acoustic signal, and a voice coil is
disposed in a magnetic gap formed in a magnetic circuit, and the voice coil is driven by an
electromagnetic force generated by a voice current flowing through the voice coil. To vibrate the
voice coil bobbin and the vibrating body connected thereto to radiate sound.
[0003]
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1
The magnetic circuit is formed by connecting a component made of a magnetic material such as
a plate or a yoke to a magnet (permanent magnet) in order to supply a uniform magnetic flux in a
magnetic gap (magnetic pole gap).
One in which a magnet is disposed inside the magnetic gap is called an internal magnetic circuit,
and one in which the magnet is disposed outside the magnetic gap is called an external magnetic
circuit.
[0004]
The magnetic circuit for the speaker is required to increase the magnetic flux density in the
magnetic gap so as to obtain a small size and a high driving force, and in order to achieve this,
magnets are disposed both inside and outside the magnetic gap. It is done.
In Patent Document 1, as shown in FIG. 1, a cylindrical outer magnet J1, a cylindrical or
cylindrical inner magnet J2 concentrically located inside the outer magnet J1, an outer magnet
J1 and an inner magnet J2 are provided. A back surface yoke J3 in close contact with the back
surface of the magnet to hold them integrally, an annular front surface yoke Y4 in close contact
with the front surface of the outer magnet J1, and a front surface of the inner magnet J2 A
magnetic circuit is described which consists of an annular or disk-shaped front inner yoke J5
forming G, and in which the polarities of the front and rear surfaces of the outer magnet J1 and
the front and rear surfaces of the inner magnet J2 are reversed.
[0005]
Moreover, in this prior art, the concave portions J3a, J3b, J4a, and J5a are formed in each yoke,
and by positioning the outer magnet J1 or the inner magnet J2 in this concave portion, the
position is close to each magnet. A magnetic gap G is formed.
[0006]
Japanese Utility Model Publication No. 58-599
[0007]
According to the conventional speaker magnetic circuit described above, the combination of the
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outer magnet J1 and the inner magnet J2 can form a magnetic gap G having a high magnetic flux
density, and a speaker with high output can be obtained.
[0008]
However, in this prior art, only the rear face of the outer magnet J1 and the inner magnet J2 is
supported by the flat rear yoke J3, the space serving as the voice coil movable range under the
magnetic gap is the outer magnet J1 or the inner side. The space is restricted by the height of the
magnet J2 and can not be made a large space.
As a result, even if magnets can be arranged both inside and outside to obtain high output, the
vibration stroke of the voice coil can not be sufficiently secured, and there is a problem that
substantially high-output speakers can not be obtained. In particular, there is a problem that it
can not be adopted for high-power speakers in the low-pitch range where the vibration stroke of
the voice coil becomes large.
[0009]
In addition, a magnetic gap G is formed between the front outer yoke J4 disposed on the front of
the outer magnet J1 and the front inner yoke J5 disposed on the front of the inner magnet J2;
Since each magnet J1,2 is positioned at J5a and the magnetic gap G is formed at a position close
to the magnet, for example, when the front positions of the outer magnet J1 and the inner
magnet J2 are shifted, the magnetic gap In order to optimize the position of G, it is necessary to
set the depths of the respective recesses J4a and J5a separately, and high processing accuracy is
required for each of the front inner yoke and the front outer yoke, resulting in complicated
manufacturing. There is a problem that it is impossible to form a magnetic gap which can easily
obtain the maximum magnetic flux density.
[0010]
The present invention has been proposed to address such problems, and in a speaker magnetic
circuit and a speaker device using the same, a speaker device with high output by securing a
large vibration stroke of a voice coil. And to optimize the magnetic flux density in the magnetic
gap relatively easily.
[0011]
In order to achieve such an object, the speaker magnetic circuit and the speaker device according
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to the present invention at least have the configurations according to the respective independent
claims below.
[0012]
According to a first aspect of the present invention, there is provided a magnetic circuit forming
a magnetic gap for vibrating a voice coil through which an audio current flows, the inner magnet
being disposed inside the magnetic gap and having a polarity in the front-rear direction and the
inner magnet. An outer magnet disposed outside the magnetic gap and having a polarity opposite
to that of the inner magnet, a first support surface supporting the rear surface of the inner
magnet, and a second support surface supporting the rear surface of the outer magnet Together
with the magnetic gap, the yoke forming a space recessed rearward with respect to the first
support surface and the second support surface, the inner plate disposed on the front surface of
the inner magnet, and the outer periphery of the inner plate An outer plate disposed in front of
the outer magnet to form the magnetic gap in the The first support surface and the second
support surface are set so that the front surface of the inner magnet and the front surface of the
outer magnet are on the same plane, and the magnetic gap is provided immediately before the
front surfaces of the inner magnet and the outer magnet. A speaker magnetic circuit
characterized in that
[0013]
[Claim 3] A voice coil bobbin around which a voice coil through which voice current flows is
wound, a vibrating body whose inner peripheral edge is connected to the voice coil bobbin and
whose outer peripheral edge is connected to a frame, and magnetism which vibrates the
vibrating body A speaker device comprising a circuit, wherein the magnetic circuit forms a
magnetic gap for vibrating the voice coil, and an inner magnet disposed inside the magnetic gap
and having polarity in the front-rear direction, and surrounding the inner magnet An outer
magnet disposed outside the magnetic gap and having a polarity opposite to that of the inner
magnet, a first support surface for supporting the rear surface of the inner magnet, and a second
support surface for supporting the rear surface of the outer magnet A space recessed rearward
with respect to the first support surface and the second support surface behind the magnetic gap
The yoke includes: a yoke to be formed; an inner plate disposed on the front surface of the inner
magnet; and an outer plate disposed on the front surface of the outer magnet so as to form the
magnetic gap at the outer periphery of the inner plate; The first support surface and the second
support surface of the inner magnet so that the front surface of the inner magnet and the front
surface of the outer magnet are on the same plane; A speaker device characterized by forming a
gap.
[0014]
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Hereinafter, embodiments of the present invention will be described with reference to the
drawings.
FIG. 2 is an explanatory view showing a speaker magnetic circuit according to an embodiment of
the present invention, wherein FIG. 2 (a) is a partial sectional perspective view and FIG. 2 (b) is a
longitudinal sectional view.
[0015]
The speaker magnetic circuit 10 has an inner magnet 11, an outer magnet 12, a yoke 13, an
inner plate 14, and an outer plate 15 as basic components, and a magnetic gap 10 G for vibrating
a voice coil (not shown) through which audio current flows. Between the outer periphery of the
outer plate 15 and the inner periphery of the outer plate 15. (In the following description, the
direction in which the sound is emitted when installed in the speaker device is referred to as
"front" The other side will be described as "after".
[0016]
The inner magnet 11 is a permanent magnet disposed inside the magnetic gap 10G and having
polarity in the front-rear direction (in the illustrated example, the front side is N pole and the rear
side is S pole), and the outer magnet 12 surrounds the inner magnet 11 As described above, the
permanent magnet is disposed outside the magnetic gap 10G and has a polarity opposite to that
of the inner magnet (in the illustrated example, the front side is the S pole and the rear side is the
N pole).
[0017]
The yoke 13 is a magnetic material member for forming the magnetic circuit 10, and has a first
support surface 13a for supporting the rear surface of the inner magnet 11 and a second support
surface 13b for supporting the rear surface of the outer magnet 12. A space 13S recessed
rearward with respect to the first support surface 13a and the second support surface 13b is
formed behind the magnetic gap 10G.
[0018]
The illustrated yoke 13 shows an example in which the bottom surface 13c of the central portion
is raised at the bottom, and a section from the rear surface of the inner magnet 11 to the rear
surface of the outer magnet 12 forms a substantially U-shaped magnetic flux line path. It is not
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limited to
[0019]
Then, the first support surface 13a and the second support surface 13b of the yoke 13 are set so
that the front surface 11a of the inner magnet 11 and the front surface 12a of the outer magnet
12 are on the same plane, and the inner magnet 11 and the outer magnet 12 are set. The inner
plate 14 is disposed on the inner magnet 11 and the outer plate 15 is disposed on the outer
magnet 12 so that the magnetic gap 10G is formed immediately before each of the front faces
11a and 12a of the A magnetic gap 10G is formed between the magnetic field 15 and the
magnetic field 15.
[0020]
In this case, the individual heights (thicknesses) of the inner magnet 11 and the outer magnet 14
may differ in design of the magnetic circuit, but taking into consideration the respective heights
of the inner magnet 11 and the outer magnet 14, the yoke The positional relationship between
the first support surface 13 a and the second support surface 13 b is set, and the front surface
11 a of the inner magnet 11 and the outer magnet 12 are in a state where the yoke 13 supports
the inner magnet 11 and the outer magnet 12. The front surface 12a is on the same plane.
[0021]
Further, in the illustrated embodiment, the inner magnet 11 is cylindrical with the center passing
through, the outer magnet 12 is annular, and the inner magnet 11 and the outer magnet 12 are
arranged concentrically.
Furthermore, in the illustrated embodiment, through holes are formed in the center of the inner
plate 14, the inner magnet 11, and the yoke 13 so as to form a through hole extending from the
front to the rear of the magnetic circuit 10. There is.
If the through hole is not required, the inner magnet 11 may be formed in a cylindrical shape.
[0022]
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One feature of such a magnetic circuit 10 is that the yoke 13 having the first support surface 13a
and the second support surface 13b for supporting the inner magnet 11 and the outer magnet
12 respectively has a space 13S behind the magnetic gap 10G. It is in the point of forming.
The space 13S is formed along the rear of the magnetic gap 10G so as to secure the vibration
stroke of the voice coil (or voice coil bobbin), thereby enabling the vibration of a large voice coil
at a large output.
[0023]
That is, according to the magnetic circuit 10 having such a configuration, a magnetic field of high
magnetic flux density can be formed in the magnetic gap 10G by the magnetic force of the inner
magnet 11 and the outer magnet 12, and further, it is formed behind the magnetic gap 10G.
Since a large vibration stroke of the voice coil can be secured by the space 13S, a drive of a large
output can be realized, and in particular, a magnetic circuit suitable for a high-power speaker in a
bass region where the vibration stroke of the voice coil becomes large. Can be formed.
[0024]
Further, another feature of the magnetic circuit 10 according to such an embodiment is that the
first support surface 13a of the yoke 13 and the front surface 11a, 12a of the inner magnet 11
and the outer magnet 12 are set on the same surface. The second support surface 13b is set, and
the magnetic gap 10G is formed immediately in front of each of the front surfaces 11a and 12a.
[0025]
According to this, since the magnetic gaps 10G are formed immediately before the front faces
11a and 12a of the inner magnet 11 and the outer magnet 12 which are on the same plane, the
magnetic force line paths from the front faces 11a and 12a to the magnetic gaps 10G are
uniform. Since the magnetic lines of force from one front surface 11a (12a) to the other front
surface 12a (11a) via the magnetic gap 10G can be shortened, a large magnetic flux density can
be formed in the magnetic gap 10G.
At this time, the state of the magnetic gap 10G can be realized only by the forming accuracy of
the yoke 13 which is a single member (the forming accuracy of the positional relationship
between the first support surface 13a and the second support surface 13b).
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[0026]
That is, in the case where the front surfaces 11a and 12a of the inner magnet 11 and the outer
magnet 12 are not on the same plane, the magnetic gap 10G is closest to the front surfaces 11a
and 11b in order to optimize the position of the magnetic gap 10G. In order to position, it is
necessary to form a recess as in the prior art to position the inner and outer magnets.
In this case, high molding accuracy of the inner plate 14 and the outer plate 15 is required, and
high molding accuracy of the two members is required, which makes the manufacturing
complicated and difficult.
[0027]
On the other hand, in this embodiment, the first support surface 13a and the second support
surface 13b of the yoke 13 are set such that the front surfaces 11a and 12a of the inner magnet
11 and the outer magnet 12 are set on the same surface. In order to form an optimum magnetic
gap 10G, it is possible to form the magnetic gap 10G at a position close to the magnet only by
disposing the inner plate 14 and the outer plate 15 on them, respectively. The molding accuracy
of 15 is not required, but the molding accuracy of only the yoke 13 which is a single member is
required.
Therefore, the optimized magnetic gap can be formed by relatively simple manufacturing.
[0028]
FIG. 3 is an explanatory view showing the function of the magnetic circuit according to the
embodiment of the present invention.
In the magnetic circuit 10, the magnetic flux emitted from the front surface of the inner magnet
11 reaches the front surface of the outer magnet 12 via the magnetic gap 10G formed between
the inner plate 14 and the outer plate 15, and exits from the rear surface of the outer magnet 12.
The magnetic flux forms a magnetic flux distribution B1 from the front surface of the inner plate
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14 to the front surface of the outer plate 15 in front of the magnetic gap 10G. Form B2.
[0029]
Therefore, as shown in FIG. 6A, when a voice current directed from the back side to the front side
of the paper flows on the voice coil 20 disposed in the magnetic gap 10G, a force acts in the
direction of the arrow F directed forward. The voice coil bobbin 21 on which the voice coil 20 is
wound is vibrated in the arrow F direction, and when the voice current in the reverse direction
flows, the voice coil bobbin 21 is vibrated in the reverse direction of the arrow F.
At this time, since the space 13S is formed behind the magnetic gap 10G by the yoke 13, the
vibration stroke to the rear of the voice coil 20 can be effectively secured in the range of the
illustrated length L.
[0030]
Further, as shown in FIG. 7B, even when the voice coil 20 is displaced forward of the magnetic
gap 10G, the leakage magnetic flux B2 is formed in the same direction as the magnetic flux in the
magnetic gap 10G. The braking force does not act on the movement in the direction of the arrow
20, and the forward swing stroke of the voice coil 20 can be effectively secured.
[0031]
Then, the front surfaces of the inner magnet 11 and the outer magnet 12 are set to be on the
same plane, and the magnetic gap 10G is formed immediately before that, so that the front
surface of the inner magnet 11 or the front surface of the outer magnet 12 moves forward The
magnetic flux in the magnetic gap 10G can be increased, as compared with the case where the
magnetic gap 10G is formed at the same position.
[0032]
Example of Magnetic Circuit (FIG. 4) and Comparative Example (FIGS. 5 to 7) FIG. 4 is an
explanatory view showing an example of dimensions of a magnetic circuit according to an
example of the present invention and magnetic gap characteristics thereof.
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FIG. 2A is a cross-sectional view corresponding to FIG. 2B (the reference numerals of the
respective parts are omitted), and FIG. 2B is an axis before and after passing through the center
of the magnetic gap 10G (L: unit mm) Is a graph showing the magnetic flux density (B: unit T) at.
[0033]
The dimensions (unit: mm) of this embodiment are a1 = φ37.5, a2 = φ39.95, a3 = φ43.05, a4 =
φ45, a5 = φ60, a6 = φ65, a7 = 11, a8 = 8. 5, a9 = 8 (magnetic gap length), a10 = 5, a11 = 32,
a12 = 19.5, a13 = φ6, using a neodymium magnet for both inside and outside, yoke: S10C, plate:
SPHC I used it.
The maximum magnetic flux density of the magnetic gap 10G in this embodiment is a large
magnetic flux density close to 1T.
[0034]
On the other hand, the comparative example shown in FIGS. 5 to 7 has the same dimensions as in
FIG. 4 except for the indicated dimensions (unit: mm), and the front faces of the inner magnet 11
and the outer magnet 12 are on the same plane (B1 = 12, b2 = 14, b3 = 2.5, FIG. 6; c1 = 15.50,
c2 = 11.50, FIG. 7; d1 = 17). .25, d2 = 9.75, d3 = 1.75).
In any of the comparative examples, the magnetic flux density in the magnetic gap is a value that
does not reach the maximum magnetic flux density of the magnetic gap 10G in the embodiment.
[0035]
[Embodiment of Speaker Device] FIG. 8 is an explanatory view (a perspective partial sectional
view) showing the speaker device according to the embodiment of the present invention, and FIG.
9 is a front perspective view showing a vibrating body employed in the speaker device. FIG.
[0036]
In the speaker device 100 according to the embodiment of the present invention, the voice coil
bobbin 21 around which the voice coil 20 through which the audio current flows is wound and
the vibration whose inner peripheral edge is connected to the voice coil bobbin 21 and whose
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outer peripheral edge is connected to the frame 40 And a magnetic circuit 10 having the features
described above for vibrating the vibrating body 30.
[0037]
An inner peripheral edge 30 a of the vibrating body 30 is connected to the voice coil bobbin 21,
and an outer peripheral edge 30 b is connected to the support portion 40 a of the frame 40 via a
semicircular edge 31.
[0038]
The vibrator 30 has a top 30c formed between the inner peripheral edge 30a and the outer
peripheral edge 30b, and the inner peripheral edge 30a and the outer peripheral edge 30b are
positioned on the front side with respect to the top 30c.
That is, the vibrating body 30 is provided with a convex dome-shaped inner portion 30A and a
partial conical outer portion 30B with a gradually expanded diameter on the front face opened at
the central portion with the top 30c as a boundary. The reinforcing rib 32 extending in the radial
direction of the vibrating body 30 is formed on the outer portion 30B via the top 30c.
Further, a convex top 30d is formed on the front side outside the inner peripheral edge 30a, and
a sub-cone 30D is formed between the top 30d and the inner peripheral edge 30a.
[0039]
The opening angle (half apex angle) of the sub-cone portion 30D is defined according to the
frequency band that reinforces the frequency characteristic of the sound wave emitted by the
vibrating body 30.
By providing the sub-cone 30D having the above-described configuration, sound waves of
desired frequency characteristics are emitted from the vibrator 30 and the sub-cone portion 30D.
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[0040]
Further, a damper 50 is provided which supports the top 30 c of the vibrating body 30 from the
rear side and supports the frame 40.
The damper 50 is formed, for example, by impregnating a cloth with a resin and performing heat
forming.
As the damper 50, for example, dampers of various shapes such as circular dampers having
concentric corrugations can be adopted, and the damper 50 has appropriate compliance and
rigidity, and the outer peripheral edge of the damper 50 is the damper support portion of the
frame 40 42, and supports the top 30c of the vibrating body 30 by the inner peripheral edge.
Further, as shown in FIG. 3, the inner peripheral edge of the damper 50 according to the present
embodiment is bent toward the front side and is formed in a shape bent along the inclined
surface of the vibrating body 30, and the top 30c is formed by an adhesive or the like. As a
result, the inner peripheral edge of the damper 50 and the top 30 c of the vibrating body 30 are
securely fixed.
[0041]
The configuration of the magnetic circuit 10 is as described above, but the materials of the inner
magnet 11 and the outer magnet 12 may be, for example, permanent magnets such as
neodymium, samarium cobalt, alnico and ferrite magnets. The material of the yoke 13 and the
inner and outer plates 14 and 15 may be, for example, a metal such as iron or a magnetic
material.
[0042]
In the frame 40, the magnetic circuit 10 is disposed at the central opening of the rear flat portion
(bottom) 41.
In addition, the frame 40 is formed so as to spread outward from the outer periphery of the rear
flat portion 41, and the damper support portion 42 is formed on a step portion formed in the
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middle thereof.
Further, a reinforcing frame 43 is attached to the front surface of the support portion 40 a of the
frame 40 so as to press and support the outer peripheral edge of the edge 31.
[0043]
The voice coil 20 is formed by, for example, winding an electric wire around a cylindrical voice
coil bobbin 21 and is fixed to the voice coil bobbin 21 so that at least a part of the voice coil 20
can vibrate in the magnetic gap 10G of the magnetic circuit 10 Be placed.
[0044]
The center cap portion 33 is formed, for example, to have an outer diameter substantially equal
to the inner diameter of the voice coil bobbin 21 and is connected to the voice coil bobbin 21 by
being fixed to the voice coil bobbin 21 with an adhesive or the like.
That is, the center cap portion 33 is formed to cover the sound output side end portion of the
voice coil bobbin 21.
[0045]
According to the speaker device 100 according to the embodiment of the present invention, in
the magnetic circuit 10, the strong magnetic force by the inner magnet 11 and the outer magnet
12 is set so that the front surface of the inner magnet 11 and the front surface of the outer
magnet 12 are coplanar. Since the magnetic gap 10G formed immediately before can be made to
act, the magnetic gap 10G of high magnetic flux density can be formed between the inner plate
14 and the outer plate 15.
[0046]
The voice coil bobbin 21 can be greatly vibrated by increasing the output of the voice current
flowing through the voice coil 20 disposed in the magnetic gap 10G, but the space 13S recessed
by the yoke 13 is behind the magnetic gap 10G. Since it is formed, it becomes possible to allow a
large amplitude of the voice coil bobbin 21 and it is possible to generate a loud bass sound that
vibrates the vibrating body 30 largely.
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[0047]
In addition, since a large vibration stroke of the voice coil bobbin 21 can be secured, the voice
coil 20 can be a long voice coil system to solve problems such as distortion of acoustic
characteristics.
[0048]
In addition, in the vibrating body 30, the apex 30c is formed between the inner peripheral edge
30a and the outer peripheral edge 30b, and the inner peripheral edge 30a and the outer
peripheral edge 30b are positioned on the front side compared to the apex 30c. Thus, the bulk in
the front-rear direction of the entire vibrating body 30 can be reduced.
And since the magnetic gap 10G is arrange | positioned in center convex dome-shaped inner part
30A, the depth of the whole speaker apparatus 100 can be compactly accommodated.
[0049]
Furthermore, since the reinforcing rib extending in the radial direction of the vibrating body 30
is formed on the vibrating body 30, the vibrating body 30 is broken even when the vibrating
body 30 having a large area is vibrated to a large extent. It can prevent.
[0050]
Further, by providing the damper 50 for supporting the top 30 c of the vibrating body 30 on the
frame 40, the vibration resistance of the voice coil bobbin 21 can be reduced as compared with
the case where the damper 50 directly supports the voice coil bobbin 21.
[0051]
It is explanatory drawing of a prior art.
It is an explanatory view showing a speaker magnetic circuit concerning one embodiment of the
present invention, and the figure (a) is a partial section perspective view, and the figure (b) is a
longitudinal section.
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It is an explanatory view showing the function of the magnetic circuit concerning the
embodiment of the present invention.
It is an explanatory view showing an example of a size of a magnetic circuit concerning an
example of the present invention, and its magnetic gap characteristic.
FIG. 2A is a cross-sectional view corresponding to FIG. 2B (the reference numerals of the
respective parts are omitted), and FIG. 2B is an axis before and after passing through the center
of the magnetic gap 10G (L: unit mm) Is a graph showing the magnetic flux density (B: unit T) at.
It is an explanatory view showing a comparative example to a magnetic circuit concerning an
example of the present invention. It is an explanatory view showing a comparative example to a
magnetic circuit concerning an example of the present invention. It is an explanatory view
showing a comparative example to a magnetic circuit concerning an example of the present
invention. It is an explanatory view (perspective perspective sectional view) showing a speaker
apparatus concerning an embodiment of the present invention. It is a front perspective view
showing a vibrator adopted for a speaker device concerning an embodiment of the present
invention.
Explanation of sign
[0052]
DESCRIPTION OF SYMBOLS 10 magnetic circuit 10G magnetic gap 11 inner magnet 11a front
12 outer magnet 12a front 13 yoke 13a first support surface 13b second support surface 13S
space 14 inner plate 15 outer plate 20 voice coil 21 voice coil bobbin 30 vibrator 30a inner
peripheral edge 30b outer Edge 30c, 30d Top 30A Inner part 30B Outer part 30D Sub cone part
40 Frame 50 Damper
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