JPH09307995

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DESCRIPTION JPH09307995
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
speaker in which a plurality of voice coils are attached to a common diaphragm in which a
plurality of cones are connected in series and integrated, a so-called multipoint speaker.
[0002]
2. Description of the Related Art In recent years, with speakers installed in televisions, display
devices for multimedia computers, etc., the installation space is limited due to the increase in
screen size, and narrow narrow elongated speakers are used.
[0003]
In such an elongated speaker, if driving is performed at one point in the center of the diaphragm,
split resonance in the long axis direction occurs and the sound quality is degraded. Therefore, a
multipoint drive type speaker is preferable.
[0004]
2. Description of the Related Art A conventional example will now be described with reference to
the drawings.
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11 is a plan view of a conventional multi-point drive speaker, FIG. 12 is a cross-sectional view
taken along the line AA in FIG. 11, FIG. 13 is a cross-sectional view taken along the line BB in FIG.
FIG. 15 is a block diagram of the first and second magnetic circuits in FIG. 11, and FIG. 16 is a
diagram for explaining the connection between the first voice coil bobbin and the second voice
coil bobbin in FIG.
[0005]
In these figures, 1 is a frame made of an elongated resin.
An outer peripheral portion of a common diaphragm 2 integrated with a plurality of cones
connected in a row is attached to a flange portion 1 a of the frame 1 via an edge 3. Furthermore,
a gasket 4 is provided on the flange portion 1 a of the frame 1.
[0006]
The diaphragm 2 is provided with a first voice coil bobbin 7 around which the voice coil 6 is
wound and a second voice coil bobbin 9 provided with a voice coil 8 (not shown) in the same
winding direction as the voice coil 6. And one end is attached. Furthermore, the open ends of the
first and second voice coil bobbins 7 and 9 on the diaphragm 2 side are sealed using caps 10 and
11.
[0007]
The first and second voice coil bobbins 7 and 9 are mounted on the frame 1 by dampers 12 and
13 whose inner peripheral portions are attached to the first and second voice coil bobbins 7 and
9 and whose outer peripheral portion is attached to the frame 1. Is attached to
[0008]
The frame 1 is provided with first and second magnetic circuits 14 and 15 so as to face the first
and second voice coil bobbins 7 and 9.
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The first magnetic circuit 14 is provided on the collar 16b of the first yoke 16 including the
cylindrical portion 16a fitted into the first voice coil bobbin 7, the collar 16b, and the first yoke
16; An annular magnet 17 disposed at an interval to the circumferential surface of the cylindrical
portion 16a of the first yoke 16, and a circumference of the cylindrical portion 16a of the first
yoke 16 provided on the magnet 17 The ring-shaped second yoke 18 disposed with a gap
(magnetic gap G) with respect to the surface and the flange portion 16b of the first yoke 16 are
provided so that the magnetizing direction is opposite to that of the magnet 17. Contact the
second yoke 18 and the canceling magnet 19 to cover the first yoke 16, the magnet 17, the
second yoke 18 and the canceling magnet 19, and It is made from the outer yoke 20. provided.
[0009]
Similarly, the second magnetic circuit 15 is provided on a cylindrical portion 26a fitted in the
second voice coil bobbin 9, a first yoke 26 including a flange 26b, and a flange 26b of the first
yoke 26. An annular magnet 27 disposed at an interval to the circumferential surface of the
cylindrical portion 26a of the first yoke 26 and having the same magnetization direction as the
magnet 17 of the first magnetic circuit 14; An annular second yoke 28 provided on the magnet
27 and disposed at a distance (magnetic gap G) from the circumferential surface of the
cylindrical portion 26 a of the first yoke 26, and the first yoke The first yoke 26, the magnet 27,
the second yoke 28 and the canceling magnet 29 are provided in the collar 26b of the No. 26
and are in a direction opposite to the magnet 17 in the magnetization direction. Yo 28 consists of
outer yoke 30. provided so as to cover the canceling magnet 29.
[0010]
The voice coils 6 and 8 of the first and second voice coil bobbins 7 and 9 are disposed in the
magnetic gaps G of the magnetic circuits 14 and 15, respectively.
Two terminals 32 and 33 are provided at the center of the frame 1. Then, the lead 34 is
connected to the terminal 32 from one end of the voice coil 6 of the first voice coil bobbin 7, the
lead 35 to the terminal 33 from the other end, and the voice coil of the second voice coil bobbin
9. The lead wire 36 is connected to the terminal 32 from one end of the lead wire 8 and the lead
wire 37 is connected to the terminal 33 from the other end.
[0011]
Since the winding direction of the voice coil 6 of the first voice coil bobbin 7 and the winding
direction of the voice coil 8 of the second voice coil bobbin 9 are the same, either one of the lead
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wires is made to match the polarity of the voice coil. In the conventional example, the lead wires
36 and 37 are folded around the voice coil 7 and connected to the voice coil 8.
[0012]
Then, when drive current is supplied to the voice coil 6 of the first voice coil bobbin 7 and the
voice coil 8 of the second voice coil bobbin 9 through the terminals 32 and 33, the first and
second voice coil bobbins 7 and 9 are produced. Performs a piston movement, the diaphragm 2
vibrates in that direction, and a sound wave is emitted from the diaphragm 2.
[0013]
However, the speaker having the above configuration has the following problems.
(1) The frame 1 is made of resin in order to reduce the leakage flux and also to reduce the cost.
In general, the linear expansion coefficient of a resin is large compared to metal. For example,
while SPC (cold-rolled steel plate) as an example of metal is 1.18 × 10 −5 cm / cm / ° C., ABS
resin as an example of resin is 3.75 × 10 −5 cm / cm / ° C. is there. On the other hand, the
linear expansion coefficient of the diaphragm 2 is almost zero.
[0014]
Therefore, only the frame 1 thermally expands due to heat generation in the magnetic circuit and
an increase in the ambient temperature around the speaker, and the first and second voice coil
bobbins 7 and 9 provided on the diaphragm 2 are on the frame 1 side. There is a problem that
so-called "gap rubbing" occurs that the magnetic gap G of the first and second magnetic circuits
14 and 15 strikes.
[0015]
(2)
The diameter of the dampers 12 and 13 is determined by the short width dimension of the
elongated frame 1, and the diameters of the dampers 12 and 13 can not be set large.
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If the diameters of the dampers 12 and 13 are limited, the amplitude can not be large, the
reproduction band is narrow, and the distortion is increased.
[0016]
(3) Although it is attached to the resin frame 1 of the first and second magnetic circuits 14 and
15 by a method such as adhesion, the number of steps is increased, and there is a problem that
the reliability with respect to the attachment strength is poor.
[0017]
(4)
Although the canceling magnets 19 and 29 are provided in the first and second magnetic circuits
14 and 15, respectively, in order to reduce the leakage magnetic flux, some magnetic flux is still
leaked from each magnetic circuit.
In a multipoint speaker, a plurality of magnetic circuits are provided, and the amount of leakage
magnetic flux is increased.
[0018]
In particular, in the case of being incorporated in a television, computer display, etc., the amount
of leakage flux is strictly limited, and therefore, a separate member for magnetic shielding is
required, resulting in an increase in cost.
[0019]
The present invention has been made in view of the above problems, and an object thereof is to
prevent gap rubbing from occurring even under high temperature, to make the diameter of the
damper large, and to attach the magnetic circuit to the frame simply and surely. To provide a
speaker with reduced leakage flux.
[0020]
According to a first aspect of the present invention for solving the above-mentioned problems,
there is provided a loudspeaker in which a plurality of voice coils are attached to a common
diaphragm integrally formed by connecting a plurality of cones in series. An elongated main
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frame to which an outer peripheral portion is attached, a sub frame of a material of linear
expansion coefficient which is attached to the main frame and smaller than a linear expansion
coefficient of a material of the main frame, and attached to the sub frame And a plurality of
magnetic circuits for driving the voice coil.
[0021]
The voice coil is provided on the diaphragm with little thermal expansion, and the magnetic
circuit is provided on the sub-frame of a material having a smaller linear expansion coefficient
than the linear expansion coefficient of the main frame material, thereby reducing the gap
rubbing of the voice coil. be able to.
[0022]
According to a second invention, in the first invention, the material of the main frame is resin,
and the material of the sub-frame is metal.
In general, since the linear expansion coefficient of metal is smaller than the linear expansion
coefficient of resin, it is possible to prevent gap scratching of the voice coil.
[0023]
An example of a particularly preferred resin is an ABS resin, and a metal is SPC (cold rolled steel
plate).
According to a third aspect of the invention, in the second aspect, when the sub-frame is metal,
the magnetic circuit and the sub-frame are attached by using "staking".
[0024]
The use of "squeeze" makes the attachment of the magnetic circuit and the sub-frame easy and
reliable.
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According to a fourth aspect of the present invention, in the first to third aspects, a hole is
formed in a side surface on the long width side of the main frame, and an extension portion
extending to the vicinity of an opening on the outer wall side of the hole of the main frame An
outer peripheral portion of a damper which is provided on the sub frame and whose inner
peripheral portion is attached to the diaphragm is attached to an extension portion of the sub
frame.
[0025]
Since the outer peripheral portion of the damper is attached to the extension of the sub-frame
located outside the main frame, the diameter of the damper can be set large, the regeneration
zone becomes wide, and the distortion is reduced.
[0026]
According to a fifth aspect of the present invention, there is provided a speaker in which a
plurality of voice coils are attached to a common diaphragm in which a plurality of cones are
connected in series and integrated, attachment of adjacent magnetic circuits of a plurality of
magnetic circuits for driving the voice coils. The magnetic direction is the reverse direction.
[0027]
By setting the magnetization directions of the adjacent magnetic circuits in opposite directions,
the magnetic flux leaking from each magnetic circuit is canceled out, and the magnetic flux
leaking from the speaker is reduced.
[0028]
DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the embodiments of the present
invention will be described with reference to the drawings.
1 is a plan partial sectional view of a multipoint driving type loudspeaker according to an
embodiment of the present invention, FIG. 2 is a sectional view taken along the section line CC in
FIG. 1, and FIG. 3 is a sectional view taken along the section line DD in FIG. 4 is an enlarged view
of a cross-sectional portion in FIG. 3, FIG. 5 is a perspective view of a main frame and a subframe in FIG. 1, FIG. 6 is a configuration diagram of first and second magnetic circuits in FIG. It is
a figure explaining the connection of the 1st voice coil bobbin in 2nd, and the 2nd voice coil
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bobbin.
[0029]
In these drawings, reference numeral 101 denotes a frame made of an elongated resin (in this
embodiment, an ABS resin).
An outer peripheral portion of a common diaphragm 102 in which a plurality of cones are
integrally connected is integrated with a flange portion 101 a of the main frame 101 via an edge
103.
Furthermore, a gasket 104 is provided on the flange portion 101 a of the main frame 101.
[0030]
The diaphragm 102 is provided with a first voice coil bobbin 107 around which the voice coil
106 is wound and a second voice coil bobbin 109 provided with a voice coil 108 (not shown) in
the same winding direction as the voice coil 106. And one end is attached.
Furthermore, the open ends of the first and second voice coil bobbins 107 and 109 on the
diaphragm 102 side are sealed using caps 110 and 111.
[0031]
At the lower part of the main frame 101, a sub-frame 150 made of metal (in the present
embodiment, SPC) is attached. Then, holes 101 b and 101 c for attaching a magnetic circuit are
formed on the bottom of the main frame 101, and holes 150 a and 150 b facing the holes 101 b
and 101 c of the main frame 101 are formed in the sub frame 150.
[0032]
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Furthermore, square holes 101d and 101e are formed on one side of the long side of the main
frame 101, and square holes 101f and 101g are also formed on the other side. In the sub-frame
150, extension parts 150c to 150f are formed which extend to the openings on the outer wall
side of the square holes 101d, 101e, 101f and 101g of the main frame 101. And the front-end ¦
tip of each extension part 150c-150f is formed in the bending part 150g-150j bent in the
direction which separates from the outer wall of the main frame 101. As shown in FIG.
[0033]
The inner peripheral portions of the dampers 112 and 113 are attached to the first and second
voice coil bobbins 107 and 109, respectively. Of the outer peripheral portions of the dampers
112 and 113, the portion facing the narrow side surface of the main frame 101 is attached to the
damper attachment portion 101h formed in the main frame 101, and the portion facing the wide
side surface of the main frame 101 is , And are attached to bent portions 150g to 150j formed at
the ends of the extending portions 150c to 150f of the sub-frame 150, respectively.
[0034]
First and second magnetic circuits 114 and 115 are attached to the sub-frame 150 so as to face
the first and second voice coil bobbins 107 and 109 in a crimp manner.
[0035]
The first magnetic circuit 114 is provided on a cylindrical portion 116a fitted in the first voice
coil bobbin 107, a first yoke 116 formed of a collar 116b, and a collar 116b of the first yoke
116. The ring-shaped magnet 117 disposed at an interval to the circumferential surface of the
cylindrical portion 116a of the first yoke 116, and the circumference of the cylindrical portion
116a of the first yoke 116 provided on the magnet 117 It is provided on the annular second
yoke 118 disposed with a gap (magnetic gap G) to the surface and at the flange 116b of the first
yoke 116, and the magnetization direction of the magnet 117 is opposite to that of the magnet
117. , A canceling magnet 119 for reducing leakage magnetic flux, a second yoke 118 and a
canceling magnet 119, and the first yoke 116, the magnet 117, the second Over click 118
consists of outer yoke 120. provided so as to cover the canceling magnet 119.
[0036]
Similarly, the second magnetic circuit 115 is provided on a cylindrical portion 126a fitted into
the second voice coil bobbin 109, a first yoke 126 having a collar portion 126b, and a collar
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portion 126b of the first yoke 126. An annular magnet 127 disposed at an interval to the
circumferential surface of the cylindrical portion 126a of the first yoke 126 and having a
magnetization direction opposite to that of the magnet 117 of the first magnetic circuit 114; An
annular second yoke 128 provided on the magnet 127 and disposed at a distance (magnetic gap
G) from the circumferential surface of the cylindrical portion 126a of the first yoke 126, and the
first yoke Provided on the collar 126b of the collar 126 and in contact with the canceling magnet
129, the second yoke 128 and the canceling magnet 129 in the direction opposite to the magnet
117 in the magnetization direction. The first yoke 126, a magnet 127, a second yoke 128,
consists outer yoke 130. provided so as to cover the canceling magnet 129.
[0037]
The voice coils 106 and 108 of the first and second voice coil bobbins are disposed in the
magnetic gaps G of the magnetic circuits 114 and 115, respectively.
At the central portion of the main frame 101, two terminals 132 and 133 are provided.
Then, the lead wire 134 is connected to the terminal 132 from one end of the voice coil 106 of
the first voice coil bobbin 107, the lead wire 135 is connected to the terminal 133 from the other
end, and the voice coil of the second voice coil bobbin 109. The lead wire 136 is connected to the
terminal 132 from one end of 107 and the lead wire 137 is connected to the terminal 133 from
the other end.
[0038]
In the present embodiment, the magnetization direction of the magnet 117 of the first magnetic
circuit 114 and the magnetization direction of the magnet 127 of the second magnetic circuit
115 are opposite to each other. Since the winding direction of the voice coil 106 disposed in the
magnetic gap G of the second embodiment and the voice coil 108 disposed in the magnetic gap G
of the second magnetic circuit 115 is the same direction, the lead wire folds as described in the
conventional example. Has become unnecessary.
[0039]
Then, when a drive current is supplied to the voice coil 106 of the first voice coil bobbin 107 and
the coil 108 of the second voice coil bobbin 109 via the terminals 132 and 133, the first and
second voice coil bobbins 107 and 109 A piston movement is performed, the diaphragm 102
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vibrates in that direction, and a sound wave is emitted from the diaphragm 102.
[0040]
According to the above configuration, the following effects can be obtained.
(1) The first and second magnetic circuits 114 and 115 are provided in the SPC subframe 150
made of a material having a smaller linear expansion coefficient than the linear expansion
coefficient of the ABS resin which is the material of the main frame 101. The gap rubbing of the
voice coils 106 and 108 of the second magnetic circuits 114 and 115 can be reduced.
[0041]
(2) The attachment of the first and second magnetic circuits 114 and 115 to the sub-frame 150
is simplified by attaching the first and second magnetic circuits 114 and 115 to the sub-frame
150 using "swimming", and Be assured.
[0042]
(3) Of the outer peripheral portions of the dampers 112 and 113, portions facing the wide side
surfaces of the main frame 101 are attached to the bent portions 150g to 150j formed at the
ends of the extended portions 150c to 150f of the sub frame 150. The diameter of the dampers
112 and 113 can be set large, the reproduction band becomes wide, and the distortion also
decreases.
[0043]
(4) By making the magnetization directions of the first and second magnetic circuits 114 and
115 reverse, the magnetic flux leaking from each magnetic circuit cancels each other out, and the
magnetic flux leaking from the speaker can be reduced.
[0044]
EXAMPLES The inventors of the present invention conducted the following experiments to
confirm the effects of the present invention.
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(1) The distortion frequency characteristics of the loudspeaker according to the embodiment and
the loudspeaker described in the conventional example were measured.
FIG. 8 is a graph showing distortion frequency characteristics of the embodiment and the
conventional speaker, in which the solid line indicates the embodiment and the broken line
indicates the conventional example.
[0045]
As can be seen from FIG. 8, it was confirmed that distortion was significantly reduced in the
entire band.
(2) The sound pressure frequency characteristics of the loudspeaker according to the
embodiment and the loudspeaker described in the conventional example were measured.
FIG. 9 is a graph showing sound pressure frequency characteristics of the embodiment and the
conventional speaker, in which the solid line indicates the embodiment and the broken line
indicates the conventional example.
[0046]
As can be seen from FIG. 9, it was confirmed that the reproduction band, in particular, the bass
range became wide.
(3) In the loudspeaker according to the embodiment, the leakage magnetic flux density when the
magnetization directions of the first magnetic circuit 114 and the second magnetic circuit 115
are changed, and the leakage magnetic flux density of the single magnetic circuit alone are
measured. Shows the result.
[0047]
As can be seen from FIG. 10, when the magnetization directions of the first magnetic circuit 114
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and the second magnetic circuit are reversed, the leakage flux density is smaller than in the case
of only one magnetic circuit, and It was confirmed that the leakage flux density was low.
[0048]
As described above, according to the present invention, the following effects can be obtained.
(1) In the speaker according to the first aspect of the present invention, a plurality of voice coils
are attached to a common diaphragm in which a plurality of cones are integrated and connected
integrally, an elongated main frame to which an outer peripheral portion of the diaphragm is
attached; A sub-frame attached to the frame and having a linear expansion coefficient smaller
than the linear expansion coefficient of the main frame material, and a plurality of magnetic
circuits attached to the sub-frame to drive the plurality of voice coils Therefore, the voice coil is
provided on the diaphragm with almost no thermal expansion, and the magnetic circuit is
provided on a sub-frame of a material having a linear expansion coefficient smaller than that of
the main frame material. Can be reduced.
[0049]
(2) In the speaker first aspect of the second aspect of the present invention, the material of the
main frame is resin, and the material of the sub frame is metal.
[0050]
In general, since the linear expansion coefficient of metal is smaller than the linear expansion
coefficient of resin, it is possible to prevent gap scratching of the voice coil.
An example of a particularly preferred resin is an ABS resin, and a metal is SPC (cold rolled steel
plate).
[0051]
(3) In the speaker second aspect of the present invention, in the case where the sub-frame is
made of metal, the magnetic circuit and the sub-frame are attached by using "squeeze".
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[0052]
The use of "squeeze" makes the attachment of the magnetic circuit and the sub-frame easy and
reliable.
(4) In the first to third inventions of the speaker according to the fourth aspect of the present
invention, a hole is formed in the side surface on the long width side of the main frame, and the
extension portion extending to the vicinity of the opening on the outer wall side of the hole of the
main frame An outer peripheral portion of a damper which is provided on the sub frame and
whose inner peripheral portion is attached to the diaphragm is attached to an extension portion
of the sub frame.
[0053]
Since the outer peripheral portion of the damper is attached to the extension of the sub-frame
located outside the main frame, the diameter of the damper can be set large, the regeneration
zone becomes wide, and distortion is reduced.
[0054]
(5) The speaker according to the fifth aspect of the present invention is a speaker in which a
plurality of voice coils are attached to a common diaphragm integrally formed by connecting a
plurality of cones in a row, and attachment of adjacent magnetic circuits of a plurality of
magnetic circuits for driving the voice coils. By making the magnetic direction reverse, the
magnetic flux leaking from each magnetic circuit is canceled out, and the magnetic flux leaking
from the speaker is reduced.
[0055]
Brief description of the drawings
[0056]
1 is a partial plan cross-sectional view of a multi-point drive speaker according to the
embodiment of the present invention.
[0057]
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2 is a cross-sectional view taken along line CC in FIG.
[0058]
3 is a cross-sectional view taken along the line D-D in FIG.
[0059]
4 is an enlarged view of a cross-sectional portion in FIG.
[0060]
5 is a perspective view of the main frame and the sub-frame in FIG.
[0061]
6 is a block diagram of the first and second magnetic circuit in FIG.
[0062]
7 is a diagram for explaining the connection of the first voice coil bobbin and the second voice
coil bobbin in FIG.
[0063]
8 is a diagram showing distortion frequency characteristics of the embodiment of the
embodiment and the conventional speaker.
[0064]
9 is a diagram showing sound pressure frequency characteristics of the embodiment of the
embodiment and the conventional speaker.
[0065]
10 is a view showing the leakage magnetic flux density when the magnetization directions of the
first magnetic circuit and the second magnetic circuit are changed in the speaker according to
the embodiment of FIG. 10, and the leakage magnetic flux density of a single magnetic circuit.
[0066]
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11 is a plan view of a conventional multi-point drive speaker.
[0067]
12 is a cross-sectional view taken along the line AA in FIG.
[0068]
13 is a cross-sectional view taken along the line BB in FIG.
[0069]
14 is an enlarged view of a cross-sectional portion in FIG.
[0070]
15 is a configuration diagram of the first and second magnetic circuit in FIG.
[0071]
16 is a diagram for explaining the connection between the first voice coil bobbin and the second
voice coil bobbin in FIG.
[0072]
Explanation of sign
[0073]
101 main frame 102 diaphragm 114, 115 magnetic circuit 150 sub frame
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