JP2010252034

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DESCRIPTION JP2010252034
PROBLEM TO BE SOLVED: To provide an electrodynamic speaker including an eccentric coneshaped diaphragm having strong directional characteristics in a direction in which a crosssectional path length of the diaphragm is long, it is possible to suppress rolling that is likely to
occur at a specific resonance frequency and the operation is stable Provided is a speaker
diaphragm that realizes an electrodynamic speaker with high efficiency of reproduction with less
malfunction such as generating sound. SOLUTION: In a speaker diaphragm including a coneshaped diaphragm main body having an outer shape and an inner shape and an edge supporting
an outer peripheral edge of the diaphragm main body, the diaphragm main body is eccentric with
respect to an outer shape center point O An eccentric cone-shaped diaphragm having a voice coil
attachment portion defined by an inner shape center point P, the edge being between the inner
periphery fixed to the outer periphery of the diaphragm body and the outer periphery fixed to
the frame The support movable portion forming the roll has ribs which radially form grooves at
positions where the support movable portion of the edge intersects the cross-sectional plane X
including the outer shape center point O and the inner shape center point P. [Selected figure]
Figure 1
Speaker diaphragm and electrodynamic speaker using the same
[0001]
The present invention relates to an electrodynamic speaker including an eccentric cone
diaphragm having a voice coil attachment portion eccentric to an outer shape, and in particular,
suppressing a rolling phenomenon which easily occurs when an eccentric cone diaphragm called
an oblique cone is provided. And an eccentric cone-shaped speaker diaphragm which realizes an
electrodynamic speaker which hardly generates abnormal noise such as a gap failure, and an
electrodynamic speaker including the same.
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[0002]
In a speaker that reproduces voice, it is required to miniaturize a space required for mounting.
In particular, the elongated (rectangular, oval (elliptical, track, etc.)) electrodynamic speaker is
affected by the divided vibration unique to the elongated speaker diaphragm in which the
diaphragm area is limited in the minor axis direction. It is difficult to obtain a large, flat
reproduction sound pressure frequency characteristic. If it is attempted to adopt a speaker
magnetic circuit having a high magnetic flux density in the magnetic gap, the width of the
magnetic circuit becomes wider than the speaker diaphragm and can not be miniaturized. There
are disadvantages in audio playback capabilities for various reasons.
[0003]
In addition, for example, in a speaker attached to a vehicle, or in an audio device such as a
display, it may be required that the sound wave emitted by the speaker is intensified in any
direction and that it has a biased directivity characteristic. In the case of a speaker of a display,
there has conventionally been one in which this is to be solved by using an eccentric cone
diaphragm (oblique cone diaphragm) (Patent Document 1 and Patent Document 2). An
electrodynamic speaker including an eccentric cone-shaped diaphragm having a voice coil
attachment portion eccentric to the outer shape can tilt the central axis of directivity
characteristics with respect to the direction of the central axis where the voice coil vibrates
(Patent Literature 3). The eccentric cone-shaped diaphragm has a characteristic that in the
frequency band higher than the lowest resonance frequency f0, the directivity characteristic in
the direction in which the sectional path length of the cone diaphragm is long is intensified and
the directivity in the opposite short direction is weakened. .
[0004]
Eccentric cone diaphragms can achieve relatively flat frequency characteristics and biased
directivity characteristics, but also have an asymmetric shape when viewed from the central axis
of the voice coil, so that the weight balance is also biased. There is a case where there is a
problem that it is easy to cause, for example, there is one that attempts to solve this by providing
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a balancer (Patent Document 4). In addition, for a speaker equipped with a rectangular flat
diaphragm to move the voice coil bobbin from the center to one short side of the rectangular flat
diaphragm, the outer peripheral portion of the rectangular flat diaphragm is used as the voice
coil drive. There is an electrodynamic speaker configured to be supported on a frame by a wide
asymmetric edge member on the short side far from the drive part of the voice coil as compared
to the near short side (Patent Document 5).
[0005]
Japanese Patent Publication No. 7-9485 Japanese Patent Application Laid-Open No. 2007288767 Japanese Patent No. 3646406 Japanese Patent No. 3405160 Japanese Patent
Application Laid-Open No. 58-92198
[0006]
In an electrodynamic speaker provided with an eccentric cone-shaped diaphragm, the crosssectional path length of the cone diaphragm can strengthen the directivity in the long direction
and weaken the directivity in the opposite short direction.
However, in an electrodynamic speaker provided with a diaphragm having an eccentric drive
position, the speaker resonance system is at a specific resonance frequency due to the weight
balance deviation of the speaker oscillation system in the frequency band including the lowest
resonance frequency f0 where the speaker oscillation system largely oscillates. When rolling
occurs, the operation becomes unstable, and there is a problem that the voice coil may come in
contact with the magnetic gap of the magnetic circuit to cause an operation failure such as
generation of abnormal noise. When the speaker vibration system including the eccentric coneshaped diaphragm and the voice coil is further provided with a balancer which tries to eliminate
the weight balance deviation, the reproduction efficiency of the electrodynamic speaker is
increased due to the weight increase of the speaker vibration system. There is a problem of
falling.
[0007]
The present invention has been made to solve the above-mentioned problems of the prior art,
and its object is to provide an electrokinetic diaphragm having an eccentric cone-shaped
diaphragm having strong directivity characteristics in the direction in which the cross-sectional
path length of the diaphragm is long. Type speaker, in particular, it is possible to suppress rolling
that is likely to occur at a specific resonance frequency, realize an electrodynamic speaker having
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high reproduction efficiency with less malfunction such as stable operation and generation of
abnormal noise. A speaker diaphragm is to be provided.
[0008]
The speaker diaphragm according to the present invention is a speaker diaphragm including a
cone-shaped diaphragm main body having an outer shape and an inner shape, and an edge
supporting the outer peripheral edge of the diaphragm main body, and the diaphragm main body
is an outer shape An eccentric cone-shaped diaphragm having a voice coil attachment portion
defined by an inner-shaped central point P eccentrically with respect to the central point O, the
edge being fixed to the inner peripheral portion and frame fixed to the outer peripheral edge of
the diaphragm main body It has a support movable part that forms a roll with the outer
peripheral part to be fixed, and the support movable part of the edge radially radiates to a
position where it crosses the cross sectional plane X including the outer shape center point O and
the inner shape center point P It has a rib that forms a groove.
[0009]
Preferably, the speaker diaphragm of the present invention is an elongated speaker diaphragm
having a diaphragm body and an edge having a major axis direction and a minor axis direction,
and an axis x defining the major axis direction of the diaphragm body. Are disposed to be
included in the cross-sectional plane X, and the support movable portion of the edge further has
a rib at the corner of the elongated roll.
[0010]
In addition, preferably, in the speaker diaphragm of the present invention, the outer shape of the
diaphragm main body is a track shape in which the axis x is in the major axis direction.
[0011]
Preferably, in the speaker diaphragm of the present invention, a plurality of ribs of the support
movable portion of the edge are arranged to be line symmetrical with respect to the axis x.
[0012]
In addition, preferably, in the speaker diaphragm of the present invention, the plurality of ribs of
the support movable portion of the edge are arranged so as to be point symmetric with respect to
the outer shape center point O.
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[0013]
Also preferably, in the speaker diaphragm according to the present invention, the plurality of ribs
of the support movable portion of the edge are disposed close to the first rib group far from the
inner shape center point P and the inner shape center point And the number of ribs of the first
rib group is equal to or less than the number of ribs of the second rib group.
[0014]
Further, an electrodynamic speaker according to the present invention includes the abovementioned speaker diaphragm, a magnetic circuit having a magnetic gap, a bobbin attached to a
voice coil attachment portion of the speaker diaphragm, and a bobbin wound around the bobbin
to produce And a coil disposed in the air gap.
[0015]
Hereinafter, the operation of the present invention will be described.
[0016]
The speaker diaphragm of the present invention is a speaker diaphragm including a cone-shaped
diaphragm main body having an outer shape and an inner shape, and an edge for supporting the
outer peripheral edge of the diaphragm main body.
The electrodynamic speaker according to the present invention comprises the speaker
diaphragm having an edge, a magnetic circuit having a magnetic gap, a bobbin attached to a
voice coil attachment portion of the speaker diaphragm, and a magnetic circuit wound around
the bobbin. And a coil disposed in the magnetic gap of
Since the diaphragm body constituting the speaker diaphragm is an eccentric cone diaphragm
having a voice coil attachment portion defined by an inner center P that is eccentric to the outer
center O, the electrodynamic speaker is It has flat frequency characteristics and strong directivity
characteristics in the direction in which the cross-sectional path length of the diaphragm body is
long.
[0017]
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Assuming that a plane including the outer center point O and the inner center point P is a crosssectional plane X, the diaphragm main body which is an eccentric cone-shaped diaphragm is
separated at the outer center point O and the inner center point P on the cross plane X As the
distance of the eccentricity when the eccentric cone-shaped diaphragm is viewed from the front
side increases, the deviation of the weight balance of the speaker vibration system increases.
The diaphragm main body may be an obtricone diaphragm having a circular outer shape and an
inner shape, or may be another eccentric eccentric diaphragm having a different shape.
As described later, in the case of an elongated speaker diaphragm having a major axis direction
and a minor axis direction, the diaphragm body is arranged such that an axis x defining the major
axis direction is included in the cross-sectional plane X.
Specifically, it is preferable that the diaphragm main body has a track shape in which the outer
diameter of the diaphragm main body is in the major axis direction of the axis x.
[0018]
On the other hand, the edge is a roll edge having an inner peripheral portion fixed to the outer
peripheral edge of the diaphragm main body, an outer peripheral portion fixed to the frame, and
a support movable portion forming a roll between them. Support the main body vibratably.
However, the support movable portion of this edge is a rib which radially forms a groove at a
position intersecting with the cross-sectional plane X including the outer shape center point O
and the inner shape center point P of the diaphragm main body which is an eccentric cone type
diaphragm. Have.
The rib formed on the roll of the supporting movable portion has a concave portion serving as a
radial groove, a first position on the cross-sectional plane X on the far side from the inner shape
center point P, and a side close to the inner shape center point P Since they are respectively
formed at the second position on the cross sectional plane X, the roll of the support movable part
is reinforced against the force moving in the direction along the cross sectional plane X.
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As a result, it is possible to suppress the rolling in the frequency band including the lowest
resonance frequency f0, and to reduce the operation failure such as the stable operation and the
generation of abnormal noise even without the balancer which reduces the reproduction
efficiency. be able to.
[0019]
The ribs formed on the roll of the support movable portion further include a plurality of ribs
arranged adjacent to these ribs in addition to those provided at the first position and the second
position intersecting the cross-sectional plane X. It may be.
For example, when a plurality of ribs of the support movable portion of the edge are arranged to
be line symmetrical with respect to the axis x, or arranged so as to be point symmetrical with
respect to the outer center point O In this case, the effect of suppressing rolling that tends to
occur in the direction of the axis x can be enhanced. Also, the plurality of ribs of the supporting
movable portion of the edge can be divided into a first rib group disposed far from the inner
center P and a second rib group disposed closer to the inner center P. In this case, if the number
of ribs in the first rib group is the same as or smaller than the number of ribs in the second rib
group, rolling may occur even if the weight balance of the speaker vibration system has a large
deviation. Can be enhanced.
[0020]
In particular, when the speaker diaphragm is a slender speaker diaphragm having a major axis
direction and a minor axis direction, and the axis x defining the major axis direction of the
diaphragm body is included in the cross-sectional plane X Preferably, the support movable
portion of the edge further has a rib at an elongated corner where the cross-sectional path length
of the roll tends to be large. The corner of the support movable portion of the elongated edge is
reinforced by providing a rib here, since stress tends to be concentrated even if the crosssectional path length of the roll does not change. As a result, it is possible to effectively suppress
rolling that is likely to occur in the major axis direction, and to realize an electrodynamic speaker
excellent in reproduction sound quality.
[0021]
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The present invention relates to an electrodynamic speaker including an eccentric cone
diaphragm having strong directivity in a direction in which the cross-sectional path length of the
diaphragm is long, and in particular, it is possible to suppress rolling that is likely to occur at a
specific resonance frequency, and the operation is stable. Accordingly, it is possible to provide an
eccentric cone-shaped diaphragm that realizes an electrodynamic speaker having a high
reproduction efficiency with less malfunction such as generation of abnormal noise.
[0022]
FIG. 1 is a perspective view illustrating an electrodynamic speaker 1 according to a preferred
embodiment of the present invention.
(Example 1) It is an A-A 'sectional view (sectional plane X) of the electrodynamic speaker 1
according to a preferred embodiment of the present invention. (Example 1) A plan view for
explaining the speaker diaphragm 2 and the edge 3 of a preferred embodiment of the present
invention, and a graph showing rolling displacement in the major axis direction. (Example 1) A
plan view illustrating the speaker diaphragm 2 and the edge 3a according to a preferred
embodiment of the present invention, and a graph showing rolling displacement in the major axis
direction. (Example 2) FIG. 5 is a plan view illustrating the speaker diaphragm 2 and the edge 3b
of a preferred embodiment of the present invention, and a graph showing rolling displacement in
the major axis direction. (Example 3) FIG. 5 is a plan view illustrating the speaker diaphragm 2
and the edge 3c of a preferred embodiment of the present invention, and a graph showing rolling
displacement in the major axis direction. (Example 4) It is a top view explaining the speaker
diaphragm 2 and edge 30 of a comparative example, and a graph showing rolling displacement
of a major axis direction. Comparative Example 1 A plan view for explaining a speaker diaphragm
25 and an edge 40 according to a preferred embodiment of the present invention, and a graph
showing rolling displacement in the major axis direction. (Example 5, Comparative Example 2)
[0023]
FIG. 1 is a perspective view illustrating an electrodynamic speaker 1 according to a preferred
embodiment of the present invention. 2 is a cross-sectional view of the electrodynamic speaker 1
taken along the line A-A '. FIG. 3 is a plan view for explaining the speaker diaphragm 2 and the
edge 3 of the electrodynamic speaker 1, and the motion in that case. It is a graph showing the
rolling displacement of the major axis direction of electric speaker 1. FIG. In addition, as
described later, a part of the structure of the electrodynamic speaker 1, an internal structure, and
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the like are omitted. The direction in which the straight line (long axis x) connecting the points OA is the major axis direction, and the direction in which the straight line (short axis y) connecting
the points O-B is the short axis direction. Further, in the electrodynamic speaker 1, the upper side
of the speaker diaphragm 2 exposed is the front side, and the lower side to which the magnetic
circuit 10 is attached is the rear side.
[0024]
The electrodynamic speaker 1 of this embodiment is a slender electrodynamic speaker having a
track-shaped speaker diaphragm 2 having a length of about 104.5 mm in the major axis
direction and a length of about 38.0 mm in the minor axis direction. It is a speaker having a
diaphragm area equal to that of a circular diaphragm having a diameter of about 6.5 cm even
though it is elongated. The speaker diaphragm 2 is an eccentric cone-shaped diaphragm, and its
outer peripheral end is supported by the edge 3, and the outer peripheral end of the edge 3 is
fixed to the frame 6. Further, a voice coil 4 is connected to the back side of the speaker
diaphragm 2 and is supported by the damper 5 so as to be capable of vibrating. In the case of the
present embodiment, the voice coil diameter of the round voice coil 4 is about 14 mm. The frame
6 has an elongated shape corresponding to the track-shaped speaker diaphragm 2, and the
magnetic circuit 10 eccentrically fixed to the frame 6 is a substantially rectangular parallelepiped
whose width is equal to or less than the length of the frame 6 in the minor axis direction. It has a
shape. Therefore, the electrodynamic speaker 1 is a speaker suitable for a device having a small
width, such as a seat of a vehicle or a side surface of a display unit of a device such as a display.
[0025]
The speaker diaphragm 2 which is an eccentric cone-shaped diaphragm is a paper cone
diaphragm formed by making and cutting a pulp material, and is formed on the outer peripheral
end 23 of the track shape centering on the outer center point O The inner peripheral portion 31
of the track-shaped edge 3 is bonded from the front side. In addition, the speaker diaphragm 2
has a circular voice coil attachment portion 20 having an inner shape center point P located at an
eccentric position with respect to the outer shape of the track shape as the center of the
concentric circle. The voice coil attachment portion 20 is a neck portion of a cone-shaped
diaphragm, and a round cylindrical bobbin 4 a constituting the voice coil 4 is adhered. The
central axis Q of the voice coil 4 is an axis passing through the inner center P, and defines a front
direction (angle θ = 0 °) in which the voice coil 4 vibrates. Therefore, in the speaker diaphragm
2 which is an eccentric cone-shaped diaphragm, the outer center point O and the inner center
point P are separated by a distance x0 (about 12 mm) on a plane orthogonal to the central axis Q
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in the major axis direction. ing.
[0026]
In addition, the first diaphragm portion 21 defined in a direction from the inner shape center
point P toward the outer shape center point O of the speaker diaphragm 2 is defined in a second
direction substantially opposite to the first diaphragm portion. A diaphragm portion 22; As
shown in FIG. 2 which is a cross-sectional view of AA ′, a cross-sectional plane defined in the
major axis direction as a plane including the outer center point O and the inner center point P of
the speaker diaphragm 2 which is an eccentric cone diaphragm. X is a virtual plane including the
major axis x. The first diaphragm portion 21 of the speaker diaphragm 2 is a curved surface
having a gentler inclination than the second diaphragm portion 22, and the second diaphragm
portion 22 of the speaker diaphragm 2 is more than the first diaphragm portion 21. It has a
narrow surface area. The first diaphragm portion 21 and the second diaphragm portion 22 are
connected so as to be smoothly continuous in the direction of the minor axis y.
[0027]
In addition, since the former is a central point of the cone-shaped voice coil attachment portion
20 and the latter is a central point of the outer peripheral end 23 of the track shape, the inner
shape center point P and the outer shape center point O of the speaker diaphragm 2 are It is
located at a position shifted in the front-rear direction on the virtual cross-sectional plane X. In
the perspective view of FIG. 1, the major axis x and the minor axis y are illustrated as straight
lines passing through the outer shape center point O, but the major axis x is a sectional plane X
including the inner shape center point P and the outer shape center point O As long as it is a
straight line located in the upper direction and orthogonal to the direction in which the voice coil
4 vibrates, it may pass through the center point P of the inner shape.
[0028]
The edge 3 is a track shape in which the inner shape of the inner peripheral portion 31 is
deformed, and the outer shape of the outer peripheral portion 32 is a track shape consisting of
straight lines and arcs, and is formed between the inner peripheral portion 31 and the outer
peripheral portion 32 The movable support portion 33 is a roll-shaped elongated edge. The edge
3 has a track-shaped long side extending linearly in the major axis direction of the speaker
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diaphragm 2 so that a free edge is formed by a linear thin-walled roll so as to freely support the
speaker diaphragm 2 On the side, a free edge that is arc-shaped in the minor axis direction is
formed, and at the corner of the track shape where the long side and the short side intersect, a
continuous roll in which the cross-sectional path length to connect these becomes large The free
edge is formed by In the present embodiment, the edge 3 is formed by impregnating a
thermosetting resin, a phenol resin as a base material, with a flexible fiber woven fabric as a base
material, and heat-molding the edge material. A gasket 34 is adhered. Further, as described later,
the edge 3 of this embodiment has a plurality of ribs 35 and 36 radially forming grooves around
a position where the support movable portion 33 intersects with the cross-sectional plane X.
[0029]
The voice coil 4 is formed of a bobbin 4a formed in a cylindrical shape and a coil 4b wound on
one end side thereof and supplied with an audio current. The external surface side of the
cylindrical surface of the bobbin 4 a is connected to the voice coil attachment portion 20 of the
speaker diaphragm 2 by an adhesive. The coil 4 b is disposed in a circular magnetic air gap 13 of
the magnetic circuit 10 described later. The tinsel wire 9 is soldered to the lead wire of the coil
4b through the metal eyelet provided on the speaker diaphragm 2 to conduct the audio current
supplied to the terminal 7 to the coil 4b. The tinsel wire 9 may be made conductive by soldering
the terminal 7 fixed to the frame 6 without the metal eyelet and the lead wire of the coil 4b.
[0030]
The damper 5 is a corrugation damper having a circular inner shape and an elongated outer
shape, which is formed by impregnating a phenolic resin as a base material with a flexible fiber
woven fabric as a base material. The inner peripheral end of the damper 5 is connected to the
cylindrical outer surface side of the bobbin 4 a to support the voice coil attachment portion 20 of
the speaker diaphragm 2. The outer peripheral end side of the damper 5 is fixed to the fixing
portion of the frame 6. Damper 5 may be a corrugation damper of another shape, or may be
formed of another material, and has an arm connecting an inner circumferential ring and an
outer circumferential ring, and is made of metal. Alternatively, it may be a butterfly damper
formed of resin.
[0031]
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The dust cap 8 of this embodiment is a substantially dome-shaped member formed by papermaking and cutting a pulp material, and is attached to the end of the bobbin 4 a of the voice coil
4 with an adhesive. The dust cap 8 is a circular dust cap corresponding to the voice coil 4 having
a cylindrical cross section, and prevents dust such as iron powder from invading the circular
magnetic gap 13 of the magnetic circuit 10. The dust cap 8 may be fixed to the speaker
diaphragm 2 with an adhesive.
[0032]
The frame 6 is an iron plate frame press-formed into a slender basket shape corresponding to the
shape of the speaker diaphragm 2, and fixes a substantially rectangular fixing portion for fixing
the edge 3, the damper 5 and the magnetic circuit 10. An eccentric fixing portion, a connecting
portion connecting the fixing portions, a window defined between the plurality of connecting
portions, and a mounting hole for mounting the terminal 7 are provided. Therefore, a speaker
vibration system including the speaker diaphragm 2, the edge 3, the voice coil 4, the dust cap 8,
and the damper 5 is vibratably supported with respect to the frame 6.
[0033]
The magnetic circuit 10 has an annular top plate 11 fixed to the frame 6, and a pole which has a
cylindrical pole and a center pole and a flat under plate inserted in a circular hole formed at the
center of the top plate 11. 12 and an annular magnet 14. The top plate 11 and the pole 12 form
a circular magnetic air gap 13 having a uniform width. The magnet 14 is bonded so as to be held
between the top plate 11 and the under plate of the pole 12. The magnet 14 of the present
embodiment is a ferrite based magnet, and may be a Nd-Fe-B based rare earth magnet having a
larger residual magnetization and coercivity, a smaller volume, or a strong coercivity. The
magnetic circuit 10 is an external magnet type magnetic circuit in which a magnet is disposed
outside the area to be projected when the coil 4b of the voice coil 4 is viewed in a plan view. If
the maximum width of the magnetic circuit 10 is reduced, The magnetic circuit 10 fits in the area
formed when the frame 6 is viewed from the front.
[0034]
Therefore, an efficient dynamic speaker 1 is realized including the adoption of a lightweight
speaker diaphragm 2. When a voice current is supplied to the coil 4b of the voice coil 4, a driving
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force acts on the voice coil 4 disposed in the magnetic gap 13, and the voice coil 4 vibrates in the
front-rear direction (vertical direction in the figure). The speaker diaphragm 2 also vibrates in the
front-rear direction. In the case of the electrodynamic speaker 1 of the present embodiment,
since the speaker diaphragm 2 which is an eccentric cone type diaphragm is provided, the voice
coil attachment portion 20 is not higher than the high limit frequency fh (= about 16 kHz). The
directivity characteristic is intensified in the direction of the first diaphragm portion 21 having a
long cross-sectional path length, and the directivity is weakened in the direction of the second
diaphragm portion 22 in which the cross-sectional path length on the opposite side is short. The
direction R in which the directivity characteristic of the speaker diaphragm 2 which is an
eccentric cone-shaped diaphragm is intensified is an angle θ (about 10) with respect to the
central axis Q of the voice coil 4 attached at an eccentric position. The direction is inclined by
about 40 °).
[0035]
Further, in the electrodynamic speaker 1 including the speaker diaphragm 2 which is an
eccentric cone-shaped diaphragm, the first diaphragm portion 21 having a larger area is larger
than the second diaphragm portion 22 having a relatively smaller area. Also, the weight of the
speaker vibration system tends to be unbalanced in the major axis x direction because the weight
is heavy. In the electrodynamic speaker 1 of this embodiment, a metal eyelet is provided on the
second diaphragm portion 22 which is lighter than the first diaphragm portion 21 of the speaker
diaphragm 2, and the lead wire of the coil 4b and the tinsel cord are provided here. Wires 9 are
drawn out and soldered on them to conduct audio current from the terminal 7 to the coil 4b. As a
result, the balance of weight balance of the speaker vibration system becomes smaller in the
direction of the major axis x, and therefore, even in the frequency band including the lowest
resonance frequency f0 where the speaker diaphragm 2, the edge 3 and the voice coil 4 largely
oscillate. The rolling which largely vibrates in the direction of the axis x is suppressed. Since it
does not necessarily further include a balancer that attempts to eliminate the weight balance
deviation, the weight increase of the speaker vibration system can be minimized, and the
regeneration efficiency of the electrodynamic speaker can be enhanced.
[0036]
Furthermore, the edge 3 for vibratably supporting the speaker diaphragm 2 of the present
embodiment has a plurality of ribs 35 radially forming grooves at positions intersecting with the
cross section plane X including the support movable portion 33 and the major axis x. And 36.
Specifically, as shown in the plan view of FIG. 3A, the rib 35 of this embodiment is on the short
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side far from the inner shape center point P, and the support movable portion 33 and the long
axis x The rib 35a is disposed at the first position on the cross-sectional plane X where the
crosses intersect, and the ribs 35b and 35c disposed at the corner where the cross-sectional path
length of the roll of the support movable portion 33 increases. Further, the rib 36 of this
embodiment is disposed on the second side on the cross-sectional plane X where the support
movable portion 33 intersects with the major axis x on the short side close to the inner shape
center point P. 36a and ribs 36b and 36c disposed at the corner where the cross-sectional path
length of the roll of the support movable portion 33 is increased.
[0037]
Each of the ribs 35a to 36c has a width of about 2.0 mm and a depth of about 1.0 mm with
respect to the front convex roller having a radial cross section of the support movable portion 33
having a radius of about 2.0 mm. The concave radial groove on the front side is formed, so that
the roll of the movable support portion 33 is effectively reinforced on the short side of the edge
3. That is, each of the ribs 35a to 36c makes the stiffness of the support movable portion 33 at
the short side intersecting the major axis x smaller than the stiffness of the other portion where
the ribs are not provided.
[0038]
The rib 35a and the rib 36a of the edge 3 of the present embodiment are disposed on the crosssectional plane X including the major axis x, and are in point symmetry with respect to the
central point O. In addition, the ribs 35b and the ribs 35c are disposed on straight lines
intersecting at an angle of about 40 ° with respect to the major axis x, and in a mutually
symmetrical relationship with the major axis x. It is arranged. The rib 36 b and the rib 36 c are
also the same. Further, the ribs 35 b and the ribs 36 b of the edge 3 are in point symmetry with
respect to the outer shape center point O, and the ribs 35 c and 36 c are also in point symmetry
with respect to the outer shape center point O. As a result, in the edge 3 of the present
embodiment, the plurality of ribs of the support movable portion 33 are disposed close to the
first rib group 35 disposed far from the inner shape center point P and the inner shape center
point It is divided into a second rib group 36, and the number of ribs of the first rib group 35
and the second rib group 36 is equal to three each.
[0039]
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As a result, the electrodynamic speaker 1 provided with the edge 3 of the present embodiment
can suppress the rolling in the direction of the long axis x despite the provision of the speaker
diaphragm 2 which is an eccentric cone-shaped diaphragm. . In the graph of FIG. 3B, when a sine
wave signal with a rated input signal of 4.9 Vrms is applied to the coil 4b of the voice coil 4, the
major axis is the vertical axis when the frequency shown in the horizontal axis is changed. It is a
frequency characteristic which takes the absolute value of the rolling displacement amplitude in
the direction of x. The measurement point of the rolling displacement amplitude is an end point
on the outer peripheral side where the second diaphragm portion 22 of the speaker diaphragm 2
illustrated in the cross-sectional view of FIG. V1 is a lower end point of the voice coil 4 illustrated
in the cross-sectional view of FIG. 2B and is a point defined on the cross-sectional plane X
including the long axis x.
[0040]
For example, the coil 4 b of the voice coil 4 disposed in the magnetic air gap 13 of the magnetic
circuit 10 is designed such that the distance between the coil 11 and the pole 12 constituting the
magnetic air gap 13 is about 0.15 mm or more. Therefore, since the absolute value of the rolling
displacement amplitude shown by these graphs is the case of a rated input signal, basically the
voice coil 4 contacts the magnetic air gap 13 of the magnetic circuit 10 to generate abnormal
noise, etc. Is not large enough to cause a malfunction. However, if the rolling displacement
amplitude in the direction of the major axis x shown on the vertical axis of the graph becomes
large, the rolling becomes large in that frequency band and the operation becomes unstable, and
the electrodynamic speaker 1 in a continuous load test or the like As a result, the edge 3 and the
damper 5 that vibratably support the speaker vibration system fatigues, causing the voice coil 4
to contact the magnetic air gap 13 of the magnetic circuit 10 to generate noise or the like. It
becomes easy to produce a malfunction.
[0041]
As shown in the graph of FIG. 3 (b), the rolling displacement in the major axis direction along the
major axis x of the electrodynamic speaker 1 of the present embodiment is about the lowest
resonance frequency f 0 = about 195 Hz and The absolute value is an end point on the outer
peripheral side of the speaker diaphragm 2 even at the lower end point v1 of the voice coil 4
although the outer peripheral portion becomes larger compared to the other frequency bands
around about 500 to 700 Hz where the divided vibration starts. Even c1 is suppressed to about
0.05 mm or less. Therefore, in the case of the electrodynamic speaker 1 of the present
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embodiment, even if rolling occurs,
[0042]
It is possible to suppress an operation failure such as generation of noise due to contact with the
magnetic gap 13. Further, by suppressing rolling around the end point c1 on the outer peripheral
side of the speaker diaphragm 2, flapping of the edge 3 is suppressed, so that the electrodynamic
speaker 1 with more excellent reproduction sound quality can be realized.
[0043]
In addition, the edge 3 is not limited to what impregnates the phenol resin which is a
thermosetting resin by using the woven fabric of a fiber as a base material, and carries out heat
forming. The edge 3 may be formed by injecting flexible foam rubber into a mold and heating
and foaming it, and it is not limited to the case where the support movable portion 33 has a roll
shape, and the outer center point O and It is also possible to use a corrugation edge composed of
a plurality of corrugations as long as ribs are formed radially in a groove at a position
intersecting the cross-sectional plane X including the internal shape center point P.
[0044]
FIG. 4 is a plan view for explaining another edge 3a constituting the electrodynamic speaker 1 in
place of the edge 3 of the previous embodiment, and shows the rolling displacement in the
longitudinal direction of the electrodynamic speaker 1 in that case. It is a graph. The edge 3a is
an edge having a similar material and shape except that the configuration of the plurality of ribs
35 and 36 is different from that of the edge 3 as shown in FIG. 4 (a). Therefore, common
reference numerals are attached to common points, and the description is omitted.
[0045]
That is, the edge 3a of the present embodiment includes the ribs 35a and the ribs 36a at
positions intersecting the cross-sectional plane X including the support movable portion 33 and
the long axis x, and the ribs 35b, 35c, 36b and in the previous embodiment. , 36c is not an edge.
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The rib 35a and the rib 36a of the edge 3a of the present embodiment are disposed on the crosssectional plane X including the major axis x, and are in point symmetry with respect to the
central point O. The ribs 35a and the ribs 36a disposed at the positions intersecting the major
axis x are the minimum configuration to suppress rolling.
[0046]
As shown in the graph of FIG. 4B, the rolling displacement in the major axis direction along the
major axis x of the electrodynamic speaker 1 provided with the edge 3a of the present
embodiment is a voice at the lowest resonance frequency f0 = about 195 Hz. Although the rolling
displacement is larger at the lower end point v1 of the coil 4 than in the previous embodiment,
its absolute value is suppressed to about 0.05 mm or less. Therefore, in the case of the
electrodynamic speaker 1 provided with the edge 3a of the present embodiment, even though
the speaker diaphragm 2 which is an eccentric cone-shaped diaphragm is provided, even if
rolling occurs, the magnetic gap 13 contacts. Malfunction can be suppressed. Further, by
suppressing rolling around the end point c1 on the outer peripheral side of the speaker
diaphragm 2, flapping of the edge 3a is suppressed, so that the electrodynamic speaker 1 with
more excellent reproduction sound quality can be realized.
[0047]
FIG. 5 is a plan view for explaining another edge 3 b which can constitute the electrodynamic
speaker 1 in place of the edges 3 and 3 a of the previous embodiment, and a graph showing
rolling displacement in the major axis direction. The edge 3 b is an edge having the same
material and shape as shown in FIG. 5A except that the configuration of the plurality of ribs 35
and 36 is different from that of the edge 3. That is, the edge 3 b is provided with the ribs 35 a
and the ribs 36 a at positions where the support movable portion 33 intersects with the cross
sectional plane X including the major axis x, and the corner portion where the cross section path
length of the roll of the support movable portion 33 becomes large. It is an edge provided with
the ribs 36b and 36c arranged and without the ribs 35b and 35c in the previous embodiment.
[0048]
The rib 35a and the rib 36a of the edge 3b in the present embodiment are disposed on the crosssectional plane X including the major axis x, and are in point symmetry with respect to the
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central point O. Further, the ribs 36b and the ribs 36c are disposed on straight lines intersecting
at an angle of 40 ° with respect to the major axis x, and arranged so as to be in line symmetry
with each other with respect to the major axis x. It is done. In the edge 3b of the present
embodiment, the plurality of ribs of the movable support portion 33 are close to the first rib
group 35 consisting of only one rib 35a disposed far from the inner shape center point P and the
inner shape center point The first rib group 35 is divided into a second rib group 36 composed
of three ribs 36 a to 36 c, and the number of ribs of the first rib group 35 is smaller than the
number of ribs of the second rib group 36.
[0049]
As shown in the graph of FIG. 5 (b), the rolling displacement in the major axis direction along the
major axis x of the electrodynamic speaker 1 provided with the edge 3b of the present
embodiment is the same as that shown in the graph of FIG. 3 (b). As in the case of providing the
edge 3 of the embodiment, the absolute value of the lower end point v1 of the voice coil 4 and
the end point c1 of the outer peripheral side of the speaker diaphragm 2 is suppressed to about
0.05 mm or less. Therefore, in the case of the electrodynamic speaker 1 provided with the edge
3b of the present embodiment, even though the speaker diaphragm 2 which is an eccentric coneshaped diaphragm is provided, even if rolling occurs, the contact is made with the magnetic gap
13 Malfunction can be suppressed. Further, by suppressing rolling around the end point c1 on
the outer peripheral side of the speaker diaphragm 2, flapping of the edge 3b is suppressed, so
that the electrodynamic speaker 1 with more excellent reproduction sound quality can be
realized.
[0050]
FIG. 6 is a plan view for explaining another edge 3c which can constitute the electrodynamic
speaker 1 in place of the edges 3, 3a, 3b of the previous embodiment, and a graph showing
rolling displacement in the major axis direction. The edge 3c is an edge having the same material
and shape as the edge 3 except that the configuration of the plurality of ribs 35 and 36 is
different from that of the edge 3 as shown in FIG. 6 (a). That is, the edge 3c is provided with the
rib 35a and the rib 36a at a position where the support movable portion 33 intersects with the
cross sectional plane X including the major axis x, and the corner portion where the cross section
path length of the roll of the support movable portion 33 becomes large It is an edge provided
with ribs 35 b and 35 c and ribs 36 b and 36 c to be arranged. Compared with the case of edge 3
of the previous embodiment, rib 35b, rib 35c, rib 36b and rib 36c are different in that they are
disposed on a straight line intersecting at an angle of 60 ° with respect to the major axis x. ing.
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[0051]
The rib 35a and the rib 36a of the edge 3c of the present embodiment are disposed on the crosssectional plane X including the major axis x, and are in point symmetry with respect to the
central point O. In addition, the ribs 35b and the ribs 35c are disposed on straight lines
intersecting at an angle of about 60 ° with respect to the major axis x, and in a mutually
symmetrical relationship with respect to the major axis x. It is arranged. The rib 36 b and the rib
36 c are also the same. Further, the rib 35b and the rib 36b of the edge 3c are in point symmetry
with respect to the outer shape center point O, and the rib 35c and the rib 36c are also in point
symmetry with respect to the outer shape center point O. As a result, in the edge 3 c of the
present embodiment, the plurality of ribs of the support movable portion 33 are disposed close
to the first rib group 35 disposed far from the inner shape center point P and the inner shape
center point It is divided into a second rib group 36, and the number of ribs of the first rib group
35 and the second rib group 36 is equal to three each.
[0052]
As shown in the graph of FIG. 6 (b), the rolling displacement in the major axis direction along the
major axis x of the electrodynamic speaker 1 provided with the edge 3c of the present
embodiment is the same as that shown in the graph of FIG. As understood from comparison with
the case where the edge 3 of the embodiment is provided, the absolute value of the rolling
displacement at the end point c1 on the outer peripheral side of the speaker diaphragm 2 is
increased to about 0.07 mm. However, at the lower end point v1 of the voice coil 4, the absolute
value of the rolling displacement is suppressed to about 0.05 mm or less. Therefore, in the case
of the electrodynamic speaker 1 provided with the edge 3c of the present embodiment of the
present embodiment, even though the speaker diaphragm 2 which is an eccentric cone-shaped
diaphragm is provided, even if rolling occurs, the magnetic It is possible to suppress an operation
failure such as generating an abnormal noise by contacting the air gap 13. (Comparative example
1)
[0053]
FIG. 7 is a plan view for explaining an edge 30 of a comparative example in which the
electrodynamic speaker 1 is configured instead of the edge 3 of the previous embodiment, and
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the rolling displacement in the longitudinal direction of the electrodynamic speaker 1 in that
case. It is a graph to represent. The edge 30 is an edge which does not have the ribs 35 and 36
as in the previous embodiment as shown in FIG. 7 (a). And, as described later, the electrodynamic
speaker 1 (not shown) having the edge 30 of the comparative example has the rolling in the
direction of the major axis x under the influence of including the speaker diaphragm 2 which is
an eccentric cone type diaphragm. growing.
[0054]
As shown in the graph of FIG. 7B, the rolling displacement in the major axis direction along the
major axis x of the electrodynamic speaker 1 provided with the edge 30 of the comparative
example is below the voice coil 4 near the lowest resonance frequency f0. At both the end point
v1 on the side and the end point c1 on the outer peripheral side of the speaker diaphragm 2, the
absolute value of the rolling displacement increases by more than about 0.07 mm. Also, as can be
seen in comparison with the case where the edge 3 of the previous embodiment shown in the
graph of FIG. 3B is provided, rolling also occurs around about 500 to 700 Hz where the outer
peripheral portion of the speaker diaphragm 2 starts divided vibration. The absolute value of
displacement increases. Therefore, in the electrodynamic speaker 1 (not shown) provided with
the edge 30 of the comparative example, the rolling in the direction of the long axis x becomes
large due to the influence provided with the speaker diaphragm 2 which is an eccentric cone
type diaphragm, The voice coil 4 may come into contact with 13 to cause an operation failure
such as generation of abnormal noise.
[0055]
As described above, the electrodynamic speaker 1 including any of the edges 3, 3a, 3b, and 3c of
the present embodiment suppresses rolling displacement in the major axis direction as compared
with the case of including the edge 30 of the comparative example. As a result, even if the
speaker diaphragm 2 which is an eccentric cone type diaphragm is provided, rolling can be
suppressed without producing a balancer which reduces the reproduction efficiency, and
abnormal noise is generated, etc. Operation failure can be suppressed. That is, the position where
the support movable portion 33 of the edge 3 crosses the cross-sectional plane X including the
outer shape center point O and the inner shape center point P of the diaphragm main body 2
which is an eccentric cone-shaped diaphragm. If the ribs 35 and 36 radially form grooves, these
ribs reinforce the roll of the movable support portion 33 against the force moving in the
direction along the cross-sectional plane X, and the speaker vibration Suppress system rolling.
The arrangement of the plurality of ribs is not limited to the above case, and may further include
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a plurality of ribs for reinforcing the corner of the support movable portion of the elongated edge
3.
[0056]
FIG. 8 is a plan view for explaining another edge 40 constituting the electrodynamic speaker 1a
(not shown) of another embodiment, and shows the rolling displacement of the electrodynamic
speaker 1a in the voice coil in that case. It is a graph. The electrodynamic speaker 1 a is a
speaker including a speaker diaphragm 25 which is an eccentric cone-shaped diaphragm having
a circular outer shape. The parts common to the above embodiment are given the same reference
numerals, and the description and illustration thereof will be omitted.
[0057]
The electrodynamic speaker 1a of the present embodiment is an oblique electrodynamic speaker
having a circular speaker diaphragm 25 having a diameter of about 12 cm. The speaker
diaphragm 25 is an eccentric cone-shaped diaphragm, and the outer peripheral end thereof is
supported by the edge 40, and the outer peripheral end of the edge 40 is fixed to a frame (not
shown). In addition, a voice coil (not shown) is connected to the back side of the speaker
diaphragm 2 and is supported so as to be able to vibrate by a damper (not shown). Further, in the
case of the present embodiment, the voice coil diameter of the round voice coil is about 20 mm.
[0058]
The speaker diaphragm 25 which is an eccentric cone-shaped diaphragm is a paper cone
diaphragm formed by making and cutting pulp material, and the inner peripheral portion of the
edge 40 at the circular outer peripheral end 28 centering on the outer center point O 41 is glued.
In addition, the speaker diaphragm 25 has a circular voice coil attachment portion 24 whose
center of concentric circle is an inner shape center point P located at an eccentric position with
respect to the circular outer shape. The voice coil attachment portion 24 is a neck portion of a
cone-shaped diaphragm, and a round cylindrical bobbin constituting a voice coil is adhered. In
the speaker diaphragm 2 which is an eccentric cone-shaped diaphragm, the outer center point O
and the inner center point P are separated by a distance x0 (about 11 mm) on a plane.
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[0059]
In addition, the first diaphragm portion 26 defined in the direction from the inner center P to the
outer center point O of the speaker diaphragm 25 and the second diaphragm defined in a
direction substantially opposite to the first diaphragm portion 26 And a diaphragm 27. The
diaphragm 27 is an eccentric cone-shaped diaphragm. The cross-sectional plane X defined as a
plane including the outer shape center point O and the inner shape center point P of the speaker
diaphragm 25 which is an eccentric cone-shaped diaphragm is the outer shape center point O
and the inner shape center point P illustrated in FIG. It is a virtual plane including the passing
axis x. The first diaphragm portion 26 of the speaker diaphragm 25 is a curved surface having a
gentler inclination than the second diaphragm portion 27, and the second diaphragm portion 27
of the speaker diaphragm 25 is more than the first diaphragm portion 26. It has a narrow
surface area.
[0060]
In the edge 40, the cross-sectional shape of the support movable portion 43 formed between the
circular inner circumferential portion 41, the circular outer circumferential portion 42, and the
inner circumferential portion 41 and the outer circumferential portion 42 is a roll-shaped edge.
The inner peripheral portion 41 of the edge 40 is bonded and connected to the outer peripheral
portion 28 from the back side of the speaker diaphragm 25. In the present embodiment, the edge
40 is formed by impregnating a thermosetting resin, a phenolic resin as a base material, with a
flexible fiber woven fabric as a base material, and heat-molding the edge, as described later. And
a plurality of ribs 45 and 46 radially forming grooves around a position intersecting with the
cross-sectional plane X. The rib 45 and the rib 46 of the edge 40 of this embodiment are
disposed on the cross-sectional plane X including the axis x, and are in point symmetry with
respect to the central point O.
[0061]
Specifically, as shown in the plan view of FIG. 8A, the rib of this embodiment is at a distant
position from the inner center P to the outer center O, and The rib 45 disposed at a first position
on the cross-sectional plane X intersecting with the axis x, and a position opposite to the outer
shape center point O from the inner shape center point P, the support movable portion 43 and
the axis x And a rib 36 disposed at a second position on the cross-sectional plane X where Each
of the ribs 45 and 46 is about 4.0 mm in width and about 2.0 mm in depth with respect to the
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front convex roller having a radial cross section of the support movable portion 43 with a radius
of about 4.0 mm. Since the front side concave radial groove is formed, the roll of the support
movable portion 43 is effectively reinforced in the direction along the axis x of the edge 40. That
is, the respective ribs 5 and 46 reduce the stiffness of the support movable portion 43 in the
vicinity of the intersection with the axis x in comparison with the stiffness of the other portion
without the ribs.
[0062]
As a result, the electrodynamic speaker 1a provided with the edge 40 of the present embodiment
can suppress the rolling in the direction of the axis x even though it is provided with the speaker
diaphragm 25 which is an eccentric cone-shaped diaphragm. In the graph of FIG. 8B, when a sine
wave signal with a rated input signal of 2.0 Vrms is applied to the coil of the voice coil, the
direction of the axis x is taken along the vertical axis when the frequency shown in the horizontal
axis is changed. The frequency characteristic is such that the absolute value of the rolling
displacement amplitude at. The measuring point of the rolling displacement amplitude is, as in
the previous embodiment, the symbol v1 is the lower end point of the voice coil and is defined on
the cross-sectional plane X including the axis x.
[0063]
As shown by the solid line in the graph of FIG. 8B, the rolling displacement in the direction along
the axis x of the electrodynamic speaker 1a of the present embodiment is about the lowest
resonance frequency f0 = about 90 Hz and that of the speaker diaphragm 25. The absolute value
is suppressed to about 0.03 mm or less at the lower end point v1 of the voice coil although the
outer peripheral part becomes larger compared to the other frequency bands around 400 to 600
Hz where the divided vibration starts . In particular, near the lowest resonance frequency f0 =
about 90 Hz, the roll is very small. Therefore, in the case of the electrodynamic speaker 1a of the
present embodiment, even if rolling occurs, operation defects such as generation of abnormal
noise due to contact with the magnetic gap can be suppressed, and reproduction sound quality is
improved. be able to. (Comparative example 2)
[0064]
The broken line in the graph of FIG. 8B indicates that the axis x is used as the axis x in the case of
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using the edge 100 (not shown) of the comparative example constituting the electrodynamic
speaker instead of the edge 40 of the previous embodiment It is a graph showing the rolling
displacement of the direction of along. The edge 100 of the comparative example is a roll edge
having substantially the same shape as the edge 40 of the previous embodiment, and is an edge
not provided with the ribs 45 and 46 as in the previous embodiment. And the dynamic dynamic
speaker (not shown) provided with the edge 40 of the comparative example becomes large in
rolling in the direction of the axis x due to the influence provided with the speaker diaphragm 25
which is an eccentric cone type diaphragm.
[0065]
As shown by the broken line in the graph of FIG. 8B, the rolling displacement in the direction
along the axis x of the electrodynamic speaker 1a provided with the edge 100 of the comparative
example is the lower side of the voice coil near the lowest resonance frequency f0. At the end
point v1 of, the absolute value of the rolling displacement increases by more than about 0.02
mm. Therefore, in the electrodynamic speaker 1a (not shown) provided with the edge 100 of the
comparative example, the rolling in the direction of the axis x becomes large due to the influence
provided with the speaker diaphragm 25 which is an eccentric cone type diaphragm, A
malfunction may occur such as contact of the voice coil to generate abnormal noise. Therefore,
the electrodynamic speaker 1a provided with the edge 40 of the present embodiment can
suppress rolling displacement in the direction along the axis x, as a result, as compared with the
case provided with the edge 100 of the comparative example. Even if the speaker diaphragm 25
which is a cone-shaped diaphragm is provided, rolling can be suppressed without providing a
balancer which reduces the reproduction efficiency, and operation defects such as generation of
abnormal noise can be suppressed. .
[0066]
That is, the position where the support movable portion 43 of the edge 40 crosses the crosssectional plane X including the outer shape center point O and the inner shape center point P of
the diaphragm main body 25 which is an eccentric cone-shaped diaphragm. If the ribs 45 and 46
radially form grooves, these ribs reinforce the roll of the support movable portion 43 against the
force moving in the direction along the cross-sectional plane X, and the speaker vibration
Suppress system rolling. Of course, the arrangement of the ribs is not limited to the above case,
and may further include a plurality of ribs adjacent to the ribs 45 and 46 to reinforce them.
Further, the inner peripheral portion 41 of the edge 40 is not limited to the case where it is
adhered to the outer peripheral portion 43 from the back side of the speaker diaphragm 25, and
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may be adhered to the outer peripheral end 28 from the front side of the speaker diaphragm 25.
[0067]
The electrodynamic speaker according to the present embodiment is not limited to the speaker
diaphragm which is an eccentric cone-shaped diaphragm whose outer shape is the abovementioned track type or circular shape, and has major axis dimensions such as oval, oval,
rectangular or rectangular. It may be a slender electrodynamic speaker having a large ratio to the
minor axis dimension. In addition, the voice coil attachment portion defined by the inner shape
center point P in the eccentric position is not limited to the above circular shape but may be a
track shape or an elliptical shape.
[0068]
The electrodynamic speaker according to the present invention is not only a speaker
incorporated in a vehicle or a video / audio apparatus such as a display, but also a game machine
such as a game machine or a game machine having a cabinet incorporating a speaker for
reproducing sound. Is also applicable.
[0069]
DESCRIPTION OF SYMBOLS 1, 1a Electrodynamic type speaker 2, 25 Speaker diaphragm 20, 24
voice coil attachment part 21, 26 1st diaphragm part 22, 27 2nd diaphragm part 23, 28 outer
peripheral end 3, 3a, 3b, 3c, 30 40, 100 edge 31, 41 inner circumferential portion 32, 42 outer
circumferential portion 33, 43 support movable portion 34 gasket 4 voice coil 5 damper 6 frame
7 terminal 8 dust cap 9 tinsel wire 10 magnetic circuit 11 top plate 12 pole 13 magnetic gap 14
magnet
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