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JP2008172479

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DESCRIPTION JP2008172479
The present invention provides a highly reliable electro-acoustic transducer (50) without causing
a defect due to a short in a voice coil lead even when vibrating with a large drive current with a
large amplitude. SOLUTION: Each frame is a substantially frame shape having an elongated
diaphragm (1), an edge (2) for supporting it, a pair of longitudinal frames (3A) and a pair of short
frames (3B) A frame (3) which has the edge (2) fixed thereto and vibratably supports the
diaphragm (1) through the edge (2), and a bobbin (4) fixed to one side of the diaphragm (1) And
a voice coil (5) wound around the outer peripheral surface of the bobbin (4) and having a pair of
end leads (25, 25) drawn from one end of the bobbin (4), and the bobbin (4) Of the magnet (7M)
disposed inside the magnet, the yoke (6) supporting the magnet (7M), and the insulating wall
provided on the yoke (6) and inserted between the pair of end leads (25, 25) And (43a). [Selected
figure] Figure 9
Electro-acoustic transducer
[0001]
The present invention relates to a diaphragm and an electro-acoustic transducer using the same,
and more particularly to a diaphragm having a narrow (elongated) shape and an electro-acoustic
transducer using the same.
[0002]
As a speaker for a television receiver or a surround system, a narrow (slender) shaped
electroacoustic transducer having space saving and excellent acoustic characteristics has
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attracted attention.
The applicant has made various proposals for such a narrow-shaped electro-acoustic transducer
[hereinafter, also simply referred to as an SPU (speaker unit)], and there is Patent Document 1 as
an example.
[0003]
The electro-acoustic transducer described in the patent document 1 is configured to support a
diaphragm formed in a substantially track shape with a rectangular frame through an edge
connected to the periphery of the diaphragm. There is. Therefore, as is apparent from FIGS. 1 and
4 of the patent document 1, the edge has a flat ring shape and the periphery thereof is connected
to the frame, so that the width of the electroacoustic transducer is the largest. The outer member
is a frame. In the following description, what integrated and integrated the diaphragm and the
edge will be referred to as a vibrator.
[0004]
On the other hand, from the market, there is a demand for a speaker unit that can obtain narrow
and wider frequency characteristics, and in order to meet this demand, the applicant of the
present invention calls itself a slim type self-designated slim type as exemplified in Patent
Document 2. An acoustic transducer is proposed.
[0005]
As apparent from FIGS. 1 and 2 of Patent Document 2, this slim type has a flange portion formed
by bending the side along the longitudinal edge, and the flange portion is fixed to the outer
surface of the frame. It is a structure.
Therefore, the outermost member in the short direction in the range corresponding to at least the
diaphragm of this electroacoustic transducer is an edge (flange portion).
[0006]
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Therefore, since the width of the diaphragm is expanded while the short width of the outer shape
is the same as, for example, the electroacoustic transducer of Patent Document 1, the slim type of
electroacoustic transducer is linear to the applied driving force. The response range can be
broadened. Then, the reproduction range on the low-frequency side can be expanded to provide a
more powerful reproduction sound. Therefore, even in the case where the width of the
diaphragm is equal to the width of the diaphragm of the electroacoustic transducer of Patent
Document 1, this slim type electroacoustic transducer is provided with a flange portion formed
by bending the side portion of the edge. By fixing the flange portion to the frame, the width of
the short side can be greatly reduced in the outer shape. For example, when the short width of
the outer shape of the electro-acoustic transducer of Patent Document 1 is 30 mm, even if the
width of the diaphragm is the same, the short width of the outer shape of the electro-acoustic
transducer of Patent Document 2 Can be reduced to 22 mm. Thus, the width of the diaphragm
can be maintained at the same width even if the width of the outer shape is reduced, so that the
linear response range of the diaphragm to the applied driving force can be maintained.
[0007]
Further, in the electroacoustic transducer described in each patent document, the yoke and the
frame are fixed by an adhesive on the side along the longitudinal direction, and the back side of
the diaphragm is substantially the same except the end in the lateral direction. It is sealed. JP,
2002-325294, A JP, 2004-297315, A
[0008]
By the way, in the slim type of electroacoustic transducer described above, the width of the
diaphragm is expanded to realize expansion of the reproduction frequency band of bass and
efficiency improvement by the inventors' investigation, and further, large input resistance
characteristics are also pursued. It became clear that the following phenomena occur as it goes
on.
[0009]
(1) The rigidity of the vibrating body composed of the edge and the vibrating plate is lowered to
disturb the frequency characteristic.
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(2) The support system for supporting the expanded vibrator and the drive system for driving the
vibrator become non-forced with respect to the vibrator, and the vibrator can not stably vibrate
with a large stroke. (3) By applying a large drive current, the heat generation from the voice coil
becomes excessive, the coil is broken, the adhesive and peripheral members are thermally
deteriorated, and the long life can not be obtained with a short life. (4) Since the back side of the
diaphragm is generally sealed except for the end in the short direction, the back pressure at the
time of large amplitude vibration becomes extremely high, and the wind from the structural gap
on the back side It becomes easy to generate turning noise. (5) At the time of large amplitude
vibration, the pair of terminal leads of the voice coil is also greatly shaken, and the possibility of
shorting due to contact with each other becomes high. Moreover, apart from the expansion of the
width of the diaphragm, if the diaphragm and the edge are joined together in the state of the
vibrator joined in the component transportation step, vibrating parts such as the diaphragm and
the roll portion of the edge contact each other There was a concern that it could be attached or
deformed.
[0010]
Therefore, the problem to be solved by the present invention corresponds to the above (5), and
even if it vibrates with a large amplitude by a large drive current, the lead of the voice coil is not
shorted and does not become defective. It is in providing a high electroacoustic transducer.
[0011]
In order to solve the above problems, the present invention has the following means 1).
1) A substantially frame shape having an elongated diaphragm (1), an edge (2) for supporting the
diaphragm (1), a pair of longitudinal frames (3A) and a pair of short frames (3B) A frame (3) in
which the edges (2) are fixed to the respective frames and the diaphragm (1) is vibratably
supported via the edges (2), and the diaphragm (1) A voice coil bobbin (4) having a
corresponding shape and fixed to one surface of the diaphragm (1), and wound around the outer
peripheral surface of the voice coil bobbin (4), and a pair of end leads (25, 25) supports a voice
coil (5) drawn from one end of the voice coil bobbin (4), a magnet (7M) disposed inside the voice
coil bobbin (4), and the magnet (7M) Yoke (6), and the yoke (6) An electric-acoustic transducer
(50), characterized in that the inserted insulating walls (43a), with a between a pair of terminal
leads (25, 25).
[0012]
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According to the diaphragm of the present invention, there is an effect that high reliability can be
obtained without shorting the leads of the voice coil and causing a defect.
[0013]
First, the SPU 50 which is an electroacoustic transducer of the embodiment will be described
with reference to FIGS.
[0014]
As shown in FIG. 1, the SPU 50 is configured to include a diaphragm 1, an edge 2, a frame 3, and
a drive unit 40 including a magnet, a yoke, and the like, which will be generally described below.
[0015]
As shown in FIGS. 4 and 5, the diaphragm 1 is an elongated and long round member having long
sides facing each other and a substantially arc-shaped portion connecting its ends.
The substantially arc-shaped portion connecting the end portions of the long sides is not limited
to this form, and the corner portion may be rounded and the whole may be substantially
rectangular.
[0016]
The edge 2 is a member which is joined to the outer peripheral side of the diaphragm 1 and
holds the diaphragm 1 so as to be able to vibrate with respect to the frame 3, and as shown in
FIG. It is a frame-like member having an opening 2A and partially having irregularities.
The edge 2 is integrally joined to the diaphragm 1 and referred to as a vibrator.
[0017]
As shown in FIG. 13, the frame 3 is a substantially rectangular frame-shaped support for
supporting the respective members, and the long and short frame portions and the outer
periphery of the edge 2 are joined to support the edge 2 It is.
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[0018]
An elongated round voice coil bobbin 4 corresponding to the shape of the diaphragm 1 is fixed to
one surface side of the diaphragm 1 (see FIG. 14).
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, which will be
described in detail later (see FIG. 7), and generates a driving force by the audio signal current and
the magnetic flux.
[0019]
Inside the frame 3 is attached a drive unit 40 which forms a magnetic circuit (see FIGS. 7 and 8).
This magnetic circuit is formed by pressing an iron plate and has a yoke 6 having a U-shaped
cross section except at both ends in the longitudinal direction, a main magnet 7M fixed inside the
yoke 6, and a tip of the magnet 7M A pole piece 8 provided to face the main vibration portion (a
range in which a concave portion is generally provided: details will be described later) of the
diaphragm 1 and a sub provided at the tip of the pole piece 8 It is comprised from the magnet
7S.
[0020]
A cushion sheet CS made of non-woven fabric or the like is attached to the end face of the sub
magnet 7S. The cushion sheet CS is used to prevent the diaphragm 1 from vibrating largely due
to excessive vibration of the diaphragm 1 and causing the concave portion 12e in the main
vibration portion 1A to collide with the sub magnet 7S violently repeatedly and damage to the
diaphragm 1 at excessive large input. It is a thing.
[0021]
Next, details of (1) diaphragm, (2) edge, (3) frame, and (4) drive unit will be described.
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[0022]
(1) Diaphragm 1 FIGS. 4 to 6 are diagrams for describing a single unit of the diaphragm 1.
4 is a perspective view as viewed from the front side, FIG. 5 is a plan view as viewed from the
front side, and FIG. 6 is a cross-sectional view taken along line S1-S1 in FIG. In FIG. 6, the vertical
direction is the driving direction V of the diaphragm 1 in the SPU 50. Also, the upper direction is
the front side, and the lower direction is the back side. In the following description, the drive
direction V substantially corresponds to the vibration direction of the diaphragm 1 and is
therefore also referred to as the vibration direction V for convenience.
[0023]
As described above, the diaphragm 1 is, for example, an elongated round member made of a long
strip having opposing long sides and a substantially arc-shaped portion connecting the ends
thereof, and the surface shape of a cylinder such as a cylinder And a base portion 1k that
protrudes to the front side, a side portion 1s that surrounds the base portion 1k, extends along
the longitudinal direction and extends generally in the vibration direction V, and a side portion
1s The sloped surface portion 1ks connected gently at the bottom end portion ST which is the
rear surface side end portion and has a curvilinear cross section, and the flange portion 1t
connected to the side end portion of the sloped surface portion 1ks ing. Here, the cross-sectional
shape of the base 1k is not limited to the arc having a constant curvature, and may be a free
curve such as a parabola.
[0024]
The side surface portion 1s is provided with a step portion 1s1, and a connecting portion
between the inclined surface portion 1ks and the collar portion 1t is provided with a projecting
portion 1ts projecting like a mountain on the front side.
[0025]
In FIG. 5, which is a plan view, the outer shape of the base 1k is formed substantially similar to
the outer shape of the diaphragm 1, and the inclined surface 1ks, the protrusion 1ts, and the
ridge 1t are also in the order of the base 1k. It is formed to surround it.
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[0026]
In the base portion 1k, concave portions 12a to 12d and concave portions 12e to 12h which are
depressed (projected to the rear side) along the vibration direction V are formed to be line
symmetrical with each other with respect to the short center line CLt. .
That is, if the cylindrical surface of the base portion 1k is a convex portion for each concave
portion, convex portions 11a to 11j and concave portions 12a to 12h are formed alternately and
continuously.
The curvatures of the concave portions 12a to 12h are the same as those of the convex portions
11a to 11j. The longitudinal range having the concavo-convex shape is referred to as a main
vibrating portion 1A for convenience, and this range substantially opposes the sub magnet 7S
(see FIG. 8).
[0027]
Flat inclined portions 1k2 and 1k2 are provided at both ends in the longitudinal direction of the
base 1k. At the central portion in the longitudinal direction, inclined portions 1k3 and 1k3
having an inclined surface which is line symmetrical with respect to the longitudinal centerline
CLn and parallel to the longitudinal centerline CLn are provided. Since the inclined portion 1k3 is
formed avoiding the vicinity of the longitudinal center line CLn, a ridgeline portion 1k4 is formed
in the central portion. Further, the depths D1 of the concave portions 12a to 12h are formed to
be approximately the same depth.
[0028]
As illustrated in FIG. 6, the inclined surface portion 1ks is formed by a curved surface (the center
of curvature is on the back side) that is convex toward the front side (the upper side in the
drawing). Further, on the inclined surface portion 1ks, convex portions 13a1 to 13h1 and 13a2
to 13h2 are formed corresponding to the respective concave portions 12a to 12h of the main
vibration portion 1A. Specifically, the protrusions 13a1 to 13h1 and 13a2 to 13h2 are formed
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such that the positions in the longitudinal direction of the recesses 12a to 12h coincide with the
width in the longitudinal direction. In addition, if the other inclined surface portion 1ks is a
concave portion with respect to the convex portions 13a1 to 13h1 and 13a2 to 13h2, the
uneven shape of the inclined surface portion 1ks has a phase opposite to that of the main
vibration portion 1A. The shape is uneven.
[0029]
The area outside the projection 1ts, that is, the ridge 1t, is subjected to bonding with the edge 2
(see FIG. 7), and the projection 1ts is also used for positioning at the time of bonding. Details of
the bonding of the diaphragm 1 and the edge 2 will be described later.
[0030]
The diaphragm 1 has heat resistance to endure heat generation when the voice coil 5 is
energized, and is formed of a polyimide (PI) film because of its excellent mechanical
characteristics as a diaphragm.
[0031]
The thickness of the diaphragm 1 is 0.125 mm, and chromium deposition is applied to the
surface on the front side.
[0032]
Further, in FIG. 7, a voice coil bobbin 4 in which a voice coil 5 is wound so as to abut on a
stepped portion 1s1 provided on the side surface portion 1s is attached to the back side (lower
side in FIG. 7) of the diaphragm 1. It is done.
[0033]
(2) Edge 2 As shown in FIG. 10, which is a perspective view, and FIG. 11, which is a short cross
section of the central portion, the edge 2 is an opening having a portion corresponding
substantially to the outer shape It is a member having a portion 2A and formed in a substantially
frame shape.
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More specifically, the flat portion 2B having the opening 2A formed on the inner peripheral side
and the roll portion 2C protruding in the form of a long circle (track shape) outside the flat
portion 2B so as to have a substantially arc shape in cross section. And a flange portion 2D which
is formed to be connected to the side portion along the longitudinal direction of the roll portion
2C and extends in the direction opposite to the projecting direction of the roll portion 2C.
[0034]
Moreover, the seat part 2E which protrudes in the side which the roll part 2C protrudes is
formed in the both ends of the longitudinal direction which is roll part 2C outer side.
The top surface of the seat 2E is set to be equal to or higher than the top of the diaphragm 1 (the
most projecting portion).
[0035]
The roll portion 2C is formed so that its cross-sectional shape gradually changes in the short side
of the edge 2, that is, in the arc-shaped portion of the roll portion 2C.
Here, in the track shape, as shown in FIG. 10, a pair of longitudinal portions (longitudinal area
LA) opposed to each other along the longitudinal direction of the edge 2 and the pair of
longitudinal portions are connected at both ends thereof It means a shape consisting of a pair of
substantially arc-shaped portions (shorter regions SA) or a substantially rectangular shape having
corners R at four corners although not shown.
[0036]
About the gradual change of this cross-sectional shape, the shape described in patent document
2 is employ ¦ adopted, and it demonstrates concretely using FIG. FIG. 12 is an enlarged view of
one corner portion P of FIG. The roll portion 2C is formed such that in the longitudinal region LA
of the edge 2, the cross-sectional shape formed by the outer shape curvature R1, the protruding
height h1 and the roll width W1 is constant. Here, the roll width W1 is the distance W1 between
the inner boundary line 2C1 and the outer boundary line 2C2 where the roll portion 2C is in
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contact with the surface (flat portion 2B) of the edge 2 and is hereinafter referred to as the
distance W1.
[0037]
This cross-sectional shape is such that the protrusion height h1 and the distance W1 gradually
expand toward the apex T of the arc in the short region SA and at the position of the central axis
CL1 extending in the longitudinal direction of the edge 2 It is formed to have the maximum
(outside curvature R2, protrusion height h2, interval W2). The roll portion 2C is formed to be
axially symmetrical with respect to the axis CL1. In the present embodiment, the enlargement
ratios R2 / R1, h2 / h1, and W2 / W1 are set to 1.2.
[0038]
The change portion M1 which is the change start point of the cross-sectional shape may not be
the connecting portion M of the longitudinal area LA and the arc-shaped area SA, and may be set
in the vicinity of the connecting portion M. Further, the vertex side end (a change end point) M2
of the gradually expanding range may be set not in the vertex T but in front of it. In any of the
embodiments, the change portion M1 (change start point) and the vertex end M2 (change end
point) are gently connected to the non-change range so that a bending line does not occur.
[0039]
Further, assuming that the roll unit 2C assumes a center line CL2 of the roll unit 2C similar to the
line 2AL of the arc-like portion in the opening 2A of the edge 2, even if the cross-sectional shape
of the roll unit 2C gradually changes, The distance Win between the inner boundary line 2C1 and
the center line CL2 and the distance Wout between the outer boundary line 2C2 and the center
line CL2 are formed to be equal.
[0040]
As a material of the edge 2 which has the roll part shape of patent document 2 demonstrated
above, butyl rubber can be used.
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The material is not limited as long as the material is excellent in heat resistance, vibration
characteristics and the like. Moreover, thickness other than seat part 2E is formed by 0.2 mm-0.3
mm.
[0041]
In the joining operation in which the diaphragm 1 and the edge 2 are joined to form a vibrator,
as shown in FIG. 7, the diaphragm 1 is inserted upward from the lower side of FIG. 7 with respect
to the opening 2A of the edge 2 Ru. At this time, the outer peripheral surface of the protrusion
1ts of the diaphragm 1 is engaged with the end surface of the opening 2A to guide the insertion.
Further, since the contact area between the two increases due to this engagement, the adhesive
between the upper surface (front surface) of the flange portion 1t of the diaphragm 1 and the
lower surface (rear surface) of the flat portion 2B of the edge 2 In the case of adhesion, the
adhesive strength is improved and both are well integrated.
[0042]
(3) Frame 3 As shown in FIG. 13, the frame 3 is a support formed in a substantially rectangular
frame shape to support each member, and includes a pair of longitudinal frames 3A in the
longitudinal direction and a pair of the transverse direction. It is formed by connecting the short
frame 3B. The frame 3 is formed by die-casting of nonmagnetic, for example, aluminum.
[0043]
The short hole 3B1 is provided in the short frame 3B for fixing the frame 3 to another member.
Further, on the inner side of the short frame 3B, a collar portion 3B2 having an arc-shaped end
portion connected to the longitudinal frame 3A is provided.
[0044]
Furthermore, a U-shaped edge cover rib 3GR is provided so as to surround the fastening hole
3B1. This is because when the edge cover rib 3GR is not provided, a force is easily applied to the
seat 2E of the protruding edge 2 at the time of assembly work of the SPU, transportation, etc.,
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and the edge 2 is therefore thin. It is a rib provided to protect the edge 2 because it is likely to
peel off or be damaged. On the other hand, in each longitudinal frame 3A, a rib 3AR that
protrudes in the direction opposite to the direction in which the edge cover rib 3GR protrudes is
formed. Further, on both end sides of the rib 3AR in the longitudinal direction, a female screw
3AR1 for screwing the yoke 6 is provided.
[0045]
The operation of fixing the edge 2 to the frame 3 will be described with reference to FIG. 7. First,
the edge 2 is placed on the frame 3 from the upper side of FIG. At this time, the tip of the edge 2
is abutted against the step 3A1.
[0046]
Then, along the longitudinal direction, the inner surface of the flange 2D of the edge 2 and the
wall portion 3A1a of the longitudinal frame 3A of the frame 3 are fixed with an adhesive. Along
the shorter direction, the lower surface of the seat 2E at the longitudinal end of the edge 2 is
fixed to the upper surface of the flange 3B2 of the frame 3 with an adhesive. By these fixations,
the frame 3 and the edge 2 are integrated, and the diaphragm 1 is supported on the frame 3 via
the edge 2 so as to be free of vibration.
[0047]
(4) Drive Unit 40 The drive unit 40 includes a voice coil bobbin 4 around which the voice coil 5
is wound, a yoke 6 fixed to the frame 3, a main magnet 7M fixed to the yoke 6, and the main
magnet 7M. It comprises the fixed pole piece 8 and the sub magnet 7S fixed to the pole piece 8.
[0048]
The voice coil bobbin 4 is formed in a shape corresponding to the outer shape of the diaphragm
1 by connecting a pair of bobbin half bodies 4 a having a bottom wall 4 a 1 shown in FIG. 14 (b).
In this embodiment, it has an oval shape having parallel opposite sides having a length Lbc. And
this voice coil bobbin 4 has a connecting wall 4b to which a bottom wall 4a1 is connected at the
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center in the longitudinal direction.
[0049]
Further, the voice coil 5 is wound around the outer peripheral surface of the voice coil bobbin 4,
and the end of the voice coil 5 is pulled out as a pair of leads 25, 25 from one short side in the
longitudinal direction of the voice coil bobbin 4. It is done. As described above, the voice coil
bobbin 4 is fixed by an adhesive so as to abut on the stepped portion 1s1 provided on the side
surface portion 1s of the diaphragm 1 (see FIG. 7).
[0050]
FIG. 9 is a perspective assembly view of the SPU 50 as viewed from the back side. In FIG. 9, the
yoke 6 has a base 6k having a U-shaped notch 6a engaged with a screw 41 for fixing the yoke 6
to the frame 3 at four corners, and the longitudinal direction of the base 6k. The central portion
has a side wall portion 6b formed by bending the side end, and is formed to have a U-shaped
cross section in the longitudinal central portion. The longitudinal length Ly of the side wall
portion 6 b is set to be substantially the same as the length Lbc of the parallel side portion of the
voice coil bobbin 4.
[0051]
Further, a rectangular cut portion 6b1 is formed at the center in the longitudinal direction of the
side wall portion 6b. When the main magnet 7M or the like is fixed to the yoke 6, the cut portion
6b1 is provided as a cut engaged with a jig for positioning in the longitudinal direction. The yoke
6 is formed by pressing an iron plate.
[0052]
An insulating separator 43 is attached to one end on the front side (lower surface side in FIG. 9)
of the yoke 6. Specifically, the separator 43 has a T-shaped cross section, and the yoke 6 has an
insulating wall 43 a projecting to the front side at the center of one end of the yoke 6 in the
longitudinal direction. It is fixed. This insulating wall 43a is inserted between the pair of leads 25
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and 25 of the voice coil 5 when the yoke 6 is fixed to the frame 3 as shown in FIG. 9, and
prevents the leads 25 from contacting each other. doing.
[0053]
This is because, when an excessive input is applied to the SPU 50 and the voice coil 5 vibrates
largely with the diaphragm 1, the leads 25 are also greatly shaken and may contact with each
other to short.
[0054]
Each lead 25 is connected to the land of the relay substrate 44 fixed by caulking to a rib 3 d for
substrate attachment provided on the frame 3.
The relay substrate 44 is provided with a connector 45 electrically connected to the land, and the
power for driving the SPU 50 is externally supplied to the voice coil 5 via the connector 45.
[0055]
Each magnet or the like is fixed to the yoke 6. As shown in FIG. 15, which is a perspective view
showing the state where the yoke 6 is removed from the SPU 50, the main magnet 7, the pole
piece 8, and the sub magnet 9 are provided on the surface of the base 6k (upper side in FIG. 15).
Are arranged in this order in the longitudinal direction and fixed by an adhesive to the base 6k.
Furthermore, a cushion sheet CS is attached to the top surface of the sub magnet 9 of each
magnet group MG.
[0056]
Each longitudinal length Lmg of the sub magnet 9 in the magnet group MG is a distance between
the outer side 1A1 from the convex portion 11a to the convex portion 11e of the diaphragm 1,
and a distance between each outer side from the convex portion 11f to the convex portion 11j. It
is set to substantially the same length as 1A1 (see FIG. 5). Further, as shown in FIG. 7, the
position and thickness in the vibration direction V of the pole piece 8 and the position and
winding width in the vibration direction V of the voice coil 5 are set so as to be substantially
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coincident with each other.
[0057]
Further, the outer peripheral surface of the voice coil bobbin 4 and the frame 3 are connected by
a suspension 42 formed in a long ring shape (see FIGS. 7 and 9). The suspension 42 is formed of
a material known as a suspension of a speaker unit (for example, "Cornex" (trade name:
registered trademark) of heat-resistant aramid fiber, etc.). Also in this embodiment, the vibration
of the voice coil bobbin 4 is appropriately damped to provide good reproduction characteristics.
Further, the suspension 42 is formed of a breathable material, or is provided with a vent and has
good breathability. Therefore, the air flow generated on the back side with the vibration of the
diaphragm 1 is not hindered.
[0058]
The SPU 50 of this embodiment is formed, for example, in the following dimensions (see FIGS. 3,
5 and 6). ・ Wide direction width Wk of base 1k: 9 mm ・ Longitudinal length of base 1k: 95
mm ・ Longitudinal length of main vibration unit 1A (1A): 80 mm ・ Horizontal width Wks of
inclined surface 1ks: 4 mm ・ Long direction of SPU 50 Length Lf: 150 mm · Width direction
width Wf of SPU 50: 30 mm
[0059]
In such a setting, when the area of the plan view (FIG. 5) of the diaphragm 1 is 1.0
(corresponding to the area of the diaphragm of Patent Document 1) of the base 1, the inclined
surface 1ks is provided. Thus, the base 1 and the inclined surface portion 1ks are combined to
increase 1.5 to 50%. Also, the drivable stroke length of the diaphragm 1 is ± 3.5 to 4.0 mm with
respect to the conventional ± 2.0 to 2.5 mm, and driving with a larger amplitude is possible. .
[0060]
Next, the operation of the SPU 50 configured as described above will be described.
[0061]
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In this configuration, when a drive current flows through the voice coil 5 wound around the voice
coil bobbin 4 in the magnetic field generated by the main magnet 7M, the pole piece 8 and the
sub magnet 7S, the electromagnetic of the drive direction V according to the drive current A
force acts on the voice coil bobbin 4 and the diaphragm 1 integrated with the coil bobbin 4
vibrates mainly in the main vibration portion 1A.
[0062]
At the time of this vibration, as described above, the flange portion 2D is formed on the side
surface of the edge 2 and the tip end side of the flange portion 2D is fixed to the frame 3, thereby
supporting the diaphragm 1 elastically mainly. Since the end of the flange portion 2D whose
edge 2 is supported by the frame 3 is positioned in the vibration direction with respect to the
outside boundary line 2C2 of the portion 2C, the width of the edge 2 is not increased. The
distance between the boundary 2C2 and the end of the flange portion 2D can be increased to
improve the linearity.
[0063]
Further, by gradually changing the cross-sectional shape of the roll portion 2C in the short area
SA so as to gradually expand from the longitudinal area LA to the top T, the linearity of the
amplitude of the diaphragm 1 is dramatically improved. While the stress level in the outer
peripheral part of the edge 2 reduces sharply, stress concentration can also be prevented.
[0064]
In the SPU 50 operating in this manner, heat is generated from the voice coil 5 during operation,
as with other SPUs.
In particular, in the case of the SPU where high input resistance is required, as in the example, a
larger current is applied to the voice coil 5 to generate a large volume, so that a large amount of
heat is generated, and a positive heat dissipation structure Desired.
[0065]
In the conventional SPU, as described above, since the yoke and the frame are fixed by the
adhesive at the side portion, the flow of air is blocked and it is difficult for the heat to be
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exhausted from the back side of the diaphragm. The back pressure of the plate was high.
If a large current is supplied to this SPU, which is difficult to be exhausted, the voice coil 5
becomes extremely high temperature, the electric wire burns out, the adhesive and other
members gradually deteriorate, and the strength decreases. There is a possibility that the
problem of shortening the life of the SPU may occur due to a change in vibration characteristics
or the like.
[0066]
On the other hand, in the SPU 50 of the embodiment, as shown in FIG. 3A and FIG. 7, the yoke 6
has four corners fastened and fixed to the frame 3 with screws.
Then, without fixing the side portions along the longitudinal direction with an adhesive, the
distance L6b between the outer side surfaces of the pair of side wall portions 6b in the yoke 6 is
smaller than the inner side distance L3A of the longitudinal frame 3A of the frame 3 and The air
gap SP is set to be provided.
As a result, the heat generated by the voice coil 5 passes through the air gap SP and is
discharged to the external space on the back side. Therefore, even if a large current is
continuously supplied to the voice coil 5, the voice coil 5 It does not become high temperature,
and the electric wire is not burnt out, the adhesive and other members are altered, the strength is
not reduced, and the vibration characteristics are not changed, and the life is extended. In this
structure, the frame 3 and the yoke 6 are not fixed at their side portions, and the longitudinal
frame 3A of the frame 3 is formed extremely thin because the short width of the SPU 50 is made
as small as possible. Therefore, in order to increase the rigidity of the frame 3 to such an extent
that the longitudinal frame 3A does not vibrate due to the vibration of the diaphragm 1, the rib
3AR is provided with a necessary thickness and height.
[0067]
Further, by providing the air gap SP, the back pressure at the time of vibration of the diaphragm
1 is significantly reduced, and the wind noise which is easily generated particularly in the low
range by the conventional SPU having a high back pressure is extremely favorably reduced. Is
ready.
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[0068]
Further, as described above, the SPU 50 of the embodiment is provided with the seat portion 2E,
and when the SPU 50 is stacked in the drive direction V, the longitudinal end or screw 41 of the
base 6k is the lower side. It abuts on the seat 2E of the SPU 50d [see FIG. 16 (a)].
[0069]
As a result, since the mass of the upper SPU 50 is received by the seat portion 2E, no load is
applied to the diaphragm 1, and the SPU 50 can be stacked without concern such as damage to
the diaphragm 1.
Therefore, conventionally, when stacking SPUs, it is necessary to insert a spacer between them so
that the diaphragm is not subjected to a load, and the man-hours and component arrangements
for that amount have been necessary. As a result, the working efficiency in manufacturing and
transportation can be greatly improved, and the member cost can be reduced.
Further, by providing the seat portion 2E, an effect such as an improvement in work efficiency
can be obtained in the manufacture and conveyance of the vibrator 51. Specifically, as shown in
FIG. 16 (b), when the vibrating body 51 in which the seat portion 2 E is joined to the vibrating
plate 1 and the edge 2 is overlapped, the seat portion in the lower vibrating body 51 It projects
so that 2E may contact ¦ abut on the lower surface side (back side of the seat part 2E) of the edge
2 in the vibrating body 51 of an upper side. Thereby, the plurality of vibrators 51 can be closely
stacked on the portion other than the seat 2E of the edge 2 and the diaphragm 1 without the
other vibrators 51 and other members coming into contact with each other. Not only space
saving is possible in storage of 51 and conveyance to the next process, but also handling of
diaphragm 51 becomes easy, so defects due to scratches on diaphragm 1 and edge 2 are greatly
reduced. .
[0070]
As shown in FIGS. 2 and 3, the SPU 50 of the embodiment is another member (hereinafter
referred to as the lower frame 3 </ b> B of the frame 3 and the lower surface of FIG. , And
referred to as a cabinet)). The attachment reference surface SF is formed on the outer peripheral
side of the back surface 3 e as a flat surface which continuously circulates.
12-05-2019
19
[0071]
Further, the position in the driving direction V of the back surface 3 e which is the reference
surface is set to be on the back side of the extreme position 2 f of the flange portion 2 D of the
edge 2. Accordingly, since the closed frame-shaped hatching range shown in FIG. 3A of the back
surface 3e is in close contact with the mounting surface of the cabinet, the sound emitted from
the diaphragm 1 to the back side is mixed with the sound emitted to the front side. And the
acoustic characteristics do not deteriorate.
[0072]
As described above, when the mounting reference surface SF is on the front side in the driving
direction V than the foremost position 2 f of the flange portion 2 D at the edge 2, the flange
portion 2 D has a positional relationship of penetrating the mounting surface. Therefore, it was
necessary to provide the cabinet with a mounting hole that provides a gap that does not contact
the flange 2D, and after mounting the SPU, it is necessary to fill the gap with a filler, according to
the embodiment There is no need for it, and the number of steps of installation work can be
reduced and high sealing performance can be obtained.
[0073]
Next, a modification of the diaphragm 1 of the SPU 50 of the embodiment will be described in
more detail.
[0074]
The diaphragm 1 described above is formed with a curved surface that is convex toward the
front side (the upper side in the figure), as shown in FIG. The diaphragms 101A and 101B may
be formed of curved surfaces that are convex (see FIGS. 17B and 17C).
Here, in the same manner as the diaphragm 1 of the embodiment, the diaphragm 101B has a
position in the driving direction V of the bottom end ST, which is an end on the inner peripheral
side of the inclined surface 1ks, an edge 2 that is an upper surface of the flange 1t. It is set so
12-05-2019
20
that it may be located in the back side rather than bonded surface SGM with it.
[0075]
As described above, since the inclined surface portion 1ks is formed by a curved surface, the
rigidity is improved and the frequency characteristic is stabilized as compared with the
diaphragm 101 [see FIG. Can also respond (oscillate) with wide linearity, and the reproduction
characteristic of the low band is improved.
[0076]
Further, as a modified example of the diaphragm 1, as shown by the one-dot chain line in FIG.
17B, the diaphragm 101A1 may have a curved surface convex toward the front side.
In addition, the diaphragms 101C and 101C1 may have the bottom end portion ST positioned on
the front side of the bonding surface SGM (see FIGS. 17D and 17E). The diaphragm 101C is an
example in which the inclined surface portion 1ks is convex toward the back side, and the
diaphragm 101C1 is convex toward the front side.
[0077]
The diaphragms 101C and 101C1 shown in FIGS. 17 (d) and 17 (e) are disposed at positions
closer to the front side than the diaphragms 101A, 101A1 and 101B, so the directivity
characteristic is improved. However, the SPU itself becomes larger in the drive direction V. With
regard to this directivity characteristic, it is desirable for the base portion 1k to obtain good
directivity characteristics as long as the curved surface portion KMB (see FIG. 6) that is a part of
the cylindrical surface is located at least the front side of the joint surface SGM. If the step 1s1 of
the side surface 1s is at the same position as the bonding surface SGM or on the front side of the
bonding surface SGM like the diaphragm 1, more preferable directivity characteristics are
obtained, which is more preferable.
[0078]
The shape of the diaphragm is a combination of the diaphragm 1 of the embodiment and the
diaphragms 101A, 101A1, 101B, 101C, 101C1 and those according to the specification required
for the SPU and the installation environment. An optimal one can be selected appropriately.
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21
[0079]
The sloped surface portion 1kss is preferably formed with a concavo-convex shape like the
diaphragm 1 of the embodiment than a flat one, and the concavities and convexities are formed
on the convex portions 11a to 11j and the concave portions 12a to 12h formed on the base 1k.
Preferably, they are provided correspondingly.
[0080]
As in the diaphragm 1, the convex-concave relationship in this correspondence may be a reverse
phase, that is, one in which the convex portions 13a1 to 13h1 and 13a2 to 13h2 are provided at
positions corresponding to the concave portions 12a to 12h of the base 1k. The projections may
be provided in the normal phase, that is, at positions corresponding to the projections 11 a to 11
j of the base 1 k.
Moreover, it is preferable to provide what becomes convex on the front side, and to set it as
uneven ¦ corrugated shape provided in the inclined surface part 1ks.
This is because, if a convex is provided on the back side, the stroke of the diaphragm is shortened
by the amount of protrusion on the back side, and the large input characteristics are limited.
[0081]
The SPU 50 of the embodiment described above is highly efficient, has less disturbance of the
reproduction frequency, is capable of stable driving with a large amplitude for a large input, is
excellent in heat dissipation characteristics, and has a long life and a high Long-term reliability is
obtained and wind noise in the low range is reduced. In addition, because stacking is easy, the
efficiency of assembly and transport work is improved, sealing performance is high in mounting
to a cabinet, and numerous effects are achieved such as no shorting between leads due to large
amplitude drive. Do.
[0082]
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22
Next, the directivity characteristic and the reproduction frequency characteristic of the SPU 50 of
the embodiment are shown in FIG. 18 and compared with the characteristics of the comparative
example. Here, the SPU of the comparative example is an SPU using a diaphragm 201 shown in
FIG. 19 instead of the diaphragm 1 of the embodiment. Here, FIGS. 19A, 19B, and 19C are an S3S3 cross-sectional view in an external perspective view, a plan view, and a plan view of the
diaphragm 201, respectively.
[0083]
In the diaphragm 201, the inclined surface portion 1ks does not have a curved surface but has a
flat inclined surface portion 201ks with respect to the diaphragm 1, and the inclined surface
portion 201ks is not provided with an uneven shape. Further, the base portion 201k is shaped so
as to be closer to the back side in the drive direction V than the diaphragm 1 of the embodiment.
[0084]
First, directivity characteristics will be described using FIG. 18 (a). The embodiment is indicated
by a solid line, and the comparative example is indicated by a broken line, and scale lines are
drawn at intervals of 5 dB in the radial direction. From this figure, it is understood that the
directional characteristic is better in the SPU 50 of the embodiment, and the difference is more
remarkable as it is separated from the front (0 °). The difference is, for example, about 5 dB at
90 ° and 270 °. As described above, this excellent directivity characteristic is obtained when
the stepped portion 1s1 of the side surface portion 1s of the diaphragm 1 is at the same position
as the bonding surface SGM and the curved surface portion KMB is on the front side than the
bonding surface SGM. Be
[0085]
Next, the reproduction frequency characteristic will be described with reference to FIG. Also in
this figure, the example is shown by a solid line and the comparative example is shown by a
broken line. It can be understood from FIG. 18 (b) that the SPU 50 of the example has no
noticeable peak or dip and there is less disturbance of the characteristics at all frequencies. In
addition, the reproduction level of the embodiment is higher in the low frequency band of 500
Hz or less, and it can be seen that the embodiment SPU 50 is particularly excellent in bass
12-05-2019
23
reproduction.
[0086]
This is due to the difference in the rigidity of the inclined surface portion 1ks. In the diaphragm 1
of the example, the inclined surface portion 1ks is curved while the inclined surface portion 1ks
of the diaphragm 201 of the comparative example is a plane. Thus, the rigidity is high, and
furthermore, by providing the uneven shape on the inclined surface portion 1ks, higher rigidity is
secured.
[0087]
It goes without saying that the embodiments of the present invention are not limited to the
above-described configurations and procedures, and may be modified within the scope of the
present invention.
It is most desirable that the position and width in the longitudinal direction correspond to the
uneven shape of the base 1k, but the position or width of the uneven shape of the inclined
surface 1ks may be changed with respect to the uneven shape of the base 1k. Moreover, what
provided uneven ¦ corrugated shape may be provided in the both ends side of a longitudinal
direction. Also, the base 1k may have a cylindrical surface shape without any uneven shape. This
is because the rigidity of the diaphragm 1 against vibration can be increased by forming the
inclined surface portion 1ks into a curved surface shape and by providing the inclined surface
portion with an uneven shape.
[0088]
It is a front side perspective view for describing the example of the electroacoustic transducer of
the present invention. It is a side view for explaining the example of the electroacoustic
transducer of the present invention. It is a back view and a back side perspective view for
describing the example of the electroacoustic transducer of this invention. It is a perspective view
for describing the example of the diaphragm of the present invention. It is a top view for
explaining the example of the diaphragm of the present invention. It is a sectional view for
explaining the example of the diaphragm of the present invention. It is a cross-sectional view for
demonstrating the Example of the electroacoustic transducer of this invention. It is a longitudinal
perspective view for describing the example of the electroacoustic transducer of the present
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invention. It is an assembly drawing for demonstrating the Example of the electroacoustic
transducer of this invention. It is a perspective view for demonstrating the edge in the Example of
the electroacoustic transducer of this invention. It is sectional drawing for demonstrating the
edge in the Example of the electroacoustic transducer of this invention. It is a fragmentary
sectional view for explaining the edge in the example of the electroacoustic transducer of the
present invention. It is five faces for demonstrating the flame ¦ frame in the Example of the
electroacoustic transducer of this invention. It is a perspective view for demonstrating the voice
coil bobbin in the Example of the electroacoustic transducer of this invention. It is a perspective
view for demonstrating the drive part in the Example of the electroacoustic transducer of this
invention. It is a figure for demonstrating the effect in the Example of the vibrator ¦ oscillator of
this invention, and an electroacoustic transducer. It is a schematic cross section for
demonstrating the modification etc. of the Example in the diaphragm of this invention. It is a
characteristic graph for demonstrating the effect of the Example of the electroacoustic
transducer of this invention. It is a figure explaining the diaphragm of a comparative example.
Explanation of sign
[0089]
DESCRIPTION OF SYMBOLS 1 diaphragm 1A main vibration part 1k base 1k2, 1k3 inclined
surface part 1k4 ridge part 1s side part 1s1 stepped part 1ks inclined surface part 1t protruding
part 1ts protruding part 2 edge 2A opening part 2B flat part 2C roll part 2C1, 2C2 boundary line
2D flange Part 2E Seat part 2f Most advanced position 3 Frame 3A Long frame 3A1 Step part
3A1a Wall part 3B Short frame 3B1 Fastening hole 3B2 Rib 3e Rear 3GR Guide rib 4 Voice coil
bobbin 4a Half body 4a1 Bottom wall 4b Connection wall 5 Voice coil 6 Yoke 6b Side Wall 6b1
Notch 6k Base 7M Main Magnet 7S Sub Magnet 8 Pole Piece 11a to 11j Convex 12a to 12h
Concave 13a1 to 13h1, 13a2 to 13h2 Convex part 25 (at the inclined surface 1) Lead 40 Drive
41 Screw 42 suspension 43 separator insulating wall 44 relay substrate 45 connector 50
electroacoustic transducer (SPU) 101A, 101A1, 101B, 101C, 101C1 (Modified example)
diaphragm CS cushion sheet CLt short center line CLn longitudinal center line D1 (recessed
section ) Depth KMB (base 1k) Curved part MG Magnet group SB Side SGM joint surface SF
attachment reference surface SP air gap ST bottom end R1 curvature V drive (vibration) direction
W1 roll width
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