JPH10294985

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DESCRIPTION JPH10294985
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
speaker capable of increasing the driving power of a cone in a magnetic circuit of limited size,
and in particular, to reduce Q at resonance in a low resonance frequency band of a small speaker.
It relates to a small speaker that can be dumped effectively.
[0002]
2. Description of the Related Art Heretofore, speakers of various shapes have been proposed. FIG.
7 shows a cross-sectional view of a speaker using a typical typical cancel magnet, and a
cylindrical center pole portion integrally formed with the disk-shaped yoke 4 at the center of the
disk-shaped yoke 4 4a is set up. In the thickness direction in the vicinity of the outer peripheral
edge of the upper surface of the yoke 4, N.D. The main drive magnet 3 magnetized with S is
attached. .
[0003]
A concentric circular plate 1 made of a magnetic material manufactured by punching or the like
is attached to the upper surface of the drive magnet 3. Further, a concentric circular cancel
magnet 5 magnetized in the direction opposite to the drive magnet 3 is attached in the vicinity of
the lower end outer periphery of the yoke 4. Further, a cylindrical shield cover 6 with a bottom is
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attached to cover the cancel magnet 5 from the plate 4 to form a magnetic circuit.
[0004]
A frame 7 having a substantially funnel-shaped cross section is attached to the upper surface of
the plate 1, and a frame 7 is formed in the magnetic gap 17 formed between the concentric plate
inner diameter 1 and the outer diameter of the center pole 4a. A voice coil bobbin 8 wound with
a voice coil 8a supported by a waveform damper 9 whose outer periphery is fixed is interposed,
and the voice coil 8a can be rocked up and down in FIG. .
[0005]
Further, a funnel-shaped cone 10 with an edge 13 whose outer periphery is fixed to the voice coil
bobbin 8 is attached to the outer periphery of the frame 7 with the arrow 12 fixed to the inner
periphery of the largest diameter.
[0006]
A cap 14 for preventing dust intrusion is covered so as to cover the upper surface of the voice
coil bobbin 8, and an audio signal is supplied to the voice coil from the input terminal 15
attached to the outer wall of the frame 7 through the tinsel wire 16.
[0007]
In contrast to the cancellation type speaker often used for the general small-sized speaker as
described above, the applicant of the present application disclosed a low-pitched voice coil
wound in the same gap of the magnetic circuit in JP-A-7-38995. Arranged so that the highfrequency bobbin on which the high-frequency voice coil is wound is located on the inner
peripheral side of the low-frequency bobbin, and further allows these bobbins to be vibrated
independently by the dump material In combination, a speaker is proposed in which these two
voice coils are disposed in the same magnetic gap in the magnetic circuit.
[0008]
Furthermore, as shown in FIG. 8 in Japanese Patent Laid-Open No. 7-250394, the present
applicant concentrically arranges the second magnetic circuit 26 comprising the pole and yoke
30 in the center pole corresponding portion formed by the first magnetic circuit 25. Also
proposed is a coaxial two-way speaker formed in
[0009]
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FIG. 8 is a side sectional view cut along the diameter direction passing through the center of the
opening as viewed from the plane of the two-way speaker, and the corresponding parts with FIG.
The first magnetic circuit 25 has a ring-shaped drive magnet 3 joined with an adhesive or the like
on a lower plate 27 made of a plate material such as pure iron formed substantially in a disk
shape, and the lower plate 27 The upper plate 1 having the same shape and the same center hole
29 is joined, and the frame 7 is fixed to the upper plate.
[0010]
The second magnetic circuit 26 is composed of a pole and yoke 30, a magnet 31 and a center
piece 28 having an outer diameter smaller than the central hole 29 in the upper plate 1 by the
gap width of the first magnetic gap 17. .
[0011]
The pole and combined yoke 30 is formed in a bottomed cylindrical shape, and a second magnet
31 magnetized in the same direction as the cylindrical drive magnet 3 is planted in the bottom of
the cylinder, and the cylindrical second magnet 31 is formed. A second magnetic gap 32 is
formed between the outer diameter of the center piece 28 and the inner circumferential portion
of the pole yoke 30 by joining a center piece 28 made of disc-shaped pure iron or the like.
[0012]
A voice coil for driving the low-medium noise cone 10 is wound around the voice coil bobbin 8 in
the first magnetic gap 17 and held by the damper 9 so as to be vertically vibrated, and in the
second magnetic gap 32. A voice coil bobbin 34a on which a voice coil 34 for driving a
diaphragm 33 having a high sound edge 22 is wound so as to be vertically vibrated by a damper
35.
The inner diameter portion of the diaphragm 33 is joined to the upper end of the voice coil
bobbin 34 a, and the outer diameter portion is joined near the inner diameter portion of the cone
10.
[0013]
Although the magnetically shielded speaker shown in FIG. 7 has a sufficient magnetic shielding
effect, magnetic leakage becomes an important problem because the speaker box used in a small
speaker is small. The magnetic shield speaker with a large size is very often used, but there is a
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problem that the resonance sharpness (Q) at the low resonance frequency f0 is large and
sufficient bass radiation can not be performed.
[0014]
Further, in the speaker shown in FIG. 8, the height of the magnetic circuit of the coaxial two-way
speaker can be reduced by using the first and second magnetic circuits to make the size smaller,
but when considering the small speaker, it is small A short voice coil is used for the voice coil
bobbin, and since the magnetic gap is small, the acoustic impedance is also small, the magnetic
force of the drive magnet of the magnetic circuit is also small, and the resonance sharpness of
the low frequency resonant frequency f0 Because the degree (Q) becomes large, it becomes
difficult to radiate the low region strongly.
In addition, since the aperture is small, the sound pressure is radiated up to the high frequency,
and it is also difficult to obtain a low to high frequency speaker.
[0015]
SUMMARY OF THE INVENTION The present invention is intended to solve the problems of
overhead, in particular to obtain a speaker capable of strongly emitting bass sound suitable for a
small speaker, and the first problem to be solved by the present invention is a simple magnetic
shield It is also a speaker, adding the driving power of two voice coils, capable of dumping the
sensitivity and Q at resonance at the low resonance frequency f0, and providing a small speaker
advantageous for bass radiation. is there.
[0016]
The second problem to be solved by the present invention is that, among the two voice coils, the
voice coil disposed at the lower side is disposed at the upper side for high-pitched sound, and the
voice coil for low-mid tone is used for coaxial two-way compactness. It is an object of the present
invention to provide a speaker which can obtain a speaker and can emit a high-frequency
reproducible low sound.
[0017]
SUMMARY OF THE INVENTION The first speaker of the present invention is, as an example of
which is shown in FIG. 1, standing on a first ring-shaped magnet 3 and yoke 4 forming a first
magnetic circuit. A second ring-shaped magnet 35 thinner than the thickness of the first ring-
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shaped magnet is disposed on the yoke 4 between the provided center poles 4a and on the first
and second ring-shaped magnets 3 and 35. First and second plates 1 and 37 are disposed to
form first and second magnetic gaps 17 and 38 between the outer diameters of first and second
plates 1 and 37 and center pole 4a. The first and second drive coils 8 and 36 are disposed in the
magnetic gaps 17 and 38, respectively, to add the driving force.
[0018]
The second speaker of the present invention, as shown in FIGS. 5 and 6, is an example of the first
ring-shaped magnet 3 and ring on a plate-like yoke 4 having a cylindrical center pole 4a at its
center. A first magnetic gap 17 formed between the inner diameter of the first plate 1 and the
outer diameter of the center pole 4a by stacking the first plates 1 of the first shape; A second
magnetic gap 38 formed between the inner diameter of the second plate 37 and the outer
diameter of the center pole 4a by laminating the two magnets 40a or 40 and the ring-shaped
second plate 37; At least one voice coil 9a, 41, 42 wound above and below at least one bobbin 14
in the second magnetic gaps 17 and 38, and adding the magnetic fluxes of the first and second
magnets It is something that was done.
[0019]
According to the configuration of the present invention, the magnetic force is added by the
second magnetic circuit provided in the first magnetic circuit, and furthermore, the mass of the
voice coil wound around the top and bottom of the voice coil bobbin causes a low resonance
frequency. It is possible to obtain a small speaker capable of dumping Q at the resonance of f0
and capable of strongly radiating the low band.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION A loudspeaker according to the present
invention will be described in detail below with reference to FIGS.
The parts corresponding to the speakers of the conventional configuration described in FIGS. 7
and 8 will be described with the same reference numerals.
[0021]
FIG. 1 is a side sectional view taken along the diametrical direction passing through the central
portion of the opening as viewed from the top of the small speaker of the present invention, and
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the yoke 4 of the speaker 20 is a disc made of a plate material such as pure iron. , A cylindrical
center pole 4a erected at the center position of the discoid portion, and a magnet guide portion
4b consisting of a step portion concentrically formed with the center pole 4a and formed in a
discoid portion It is formed.
[0022]
In the thickness direction of ferrite or the like, N. N. The ring-shaped outer magnet 3 which is
magnetized or not and is bonded to S via an adhesive.
The inner diameter of the ring-shaped outer magnet 3 is fitted to the step of the magnet guide
portion 4b formed in the disk-like portion of the yoke 4 and positioned.
[0023]
In a general small speaker 20, the width w between the outer diameter of the center pole 4a and
the inner diameter of the outer magnet 3 is made quite wide, and a substantially cylindrical space
18 is formed.
[0024]
Therefore, in the speaker 20 of this embodiment, the inner magnet 35 is disposed in the space
18 formed in the inner diameter of the center pole 4 a and the outer magnet 3.
[0025]
The inner magnet 35 is made of N.N. The inner magnet 35 is bonded to the step portion of the
magnet guide 4 b of the yoke 4 via an adhesive.
[0026]
Next, a gap guide (not shown) having a cylindrical and gap width thickness is inserted into the
outer diameter of the center pole 4a, and an adhesive is applied to the upper surfaces of the
inner and outer magnets 35 and 3, respectively. The inner diameter of the through hole formed
in the second plate 37 and the first plate 1 is inserted into the outer diameter of the gap guide to
bond the second and first plates 37 and 1 to the upper surfaces of the magnets 35 and 3
respectively.
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[0027]
The frame 7 formed in a funnel shape with steel or the like is fixed in advance on the first plate 1
with scissors or screwed on the first plate 1 through a screw or the like, thereby forming the
magnetic circuit The hardware part is completed.
[0028]
After removing the above-mentioned gap guide from the center pole 4a, a spacer is inserted on
the inner periphery of the voice coil bobbin 8 so that the voice coils 8a and 36 come to
predetermined positions in the first and second magnetic gaps 17 and 38. The voice coil bobbin
8 and the spacer are inserted from the tip of the center pole 4a after setting.
[0029]
Next, the waveform lower damper 9 a and the upper damper 9 b are joined between the outer
periphery of the voice coil bobbin 8 and the bottom surface of the frame 7 as needed, and the
voice coil bobbin 8 is held.
In this example, since the voice coil bobbin 8 extends downward and the mass of the vibration
system increases, it is possible to use two dampers 9a and 9b.
In this way, it is possible to prevent the rolling caused by the long voice coil bobbin.
[0030]
In this example, the length of the voice coil bobbin 8 is increased by a predetermined length, and
adjustment is made to add a predetermined mass to the cone 10.
Accordingly, the end of the voice coil bobbin 8 extends at least from the second magnetic gap 38
in the space 18 to the lower surface.
[0031]
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Furthermore, the inner diameter of a funnel-shaped cone 10 with an edge 13 made of paper or
the like is joined to the upper outer diameter portion of the voice coil bobbin 8 and the largest
diameter portion of the cone 10 is an arrowhead 12 at the upper opening peripheral portion of
the frame 7 After the spacer inserted and fixed to the inner periphery of the voice coil bobbin 8
is removed, a cap 14 for preventing dust intrusion is adhered to the upper end of the voice coil
bobbin 8.
The tinsel wire 16 is connected to the voice coil 8a, and an audio signal is supplied to the voice
coil 8a through the input terminal 15 attached to the frame 7.
[0032]
Also, in the case of using the non-magnetized outer and inner magnets 3 and 35, it is sufficient to
simultaneously magnetize in a state where bonding of the adhesive is complete.
[0033]
If a magnetic shielding type magnet is required, the cancel magnet 5 and the shield cover 6
magnetized oppositely to the outer and inner magnets may be provided as in the conventional
case of FIG.
[0034]
According to the above-described speaker, if voice coils 8a and 36 in the first magnetic gap 17
and the second magnetic gap 38 are connected in series or in parallel, the cone 10 becomes the
first and second magnetic gaps. In order to obtain an induced force which is generated by the
magnetic flux interlinking in the two magnetic paths of the sections 17 and 38, an additive
driving force is obtained which emits strong radiation in the bass range.
[0035]
Also, since the voice coil bobbin 8 is extended to the positions of the upper voice coil 8 a and the
lower voice coil 36 vibrating in the first and third magnetic gaps 17 and 38 as compared with
the normal voice coil, The mass is increased by the voice coil bobbin 8.
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Therefore, since it is possible to dump Q at resonance at the low resonance frequency f0 at the
lowest frequency with this mass, a small speaker advantageous to bass radiation can be obtained.
[0036]
Although the voice coil 36 is disposed in the second magnetic gap 38 in the speaker 20 having
the above-described configuration, the conductor short coil 42 may be disposed at the position of
the voice coil 36 as shown in FIG. Good.
[0037]
Hereinafter, this example will be described with reference to FIG. 2, but in each embodiment
described below, the corresponding parts with FIG. 1 will be assigned the same reference
numerals and redundant explanations will be omitted, and only differences with FIG.
[0038]
In the case of FIG. 2, the second magnetic gap 38 between the second plate 37 of the inner
magnet 35 and the center pole 4a disposed in the space 18 is a strong magnet such as samarium
cobalt. The magnetic flux density of the second magnetic gap 38 is large, and by providing a
short coil (for example, a copper short ring) of a conductor for high-pitched sound in this portion,
an electromagnetic braking force can be applied to the conductor.
Therefore, this damping force can change the acoustic impedance of the vibration system of the
voice coil bobbin, and in particular, a small speaker capable of dumping Q at the time of
resonance at a low resonance frequency can be obtained.
[0039]
FIGS. 3 and 4 show still another example of the speaker according to the present invention,
which is used as a coaxial two-way speaker and for upper and lower voice coils 8 and 36
disposed in the space 18 for upper and lower voices. And the drive of the cone.
[0040]
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Also in FIGS. 3 and 4, only the differences from FIG. 1 will be described in detail.
In the case of FIG. 3, the voice coil bobbin 8 vibrating in the first magnetic gap 17 may be short,
and the voice coil 8a wound around the voice coil bobbin 8 drives the low-mid tone cone 10.
In this example, the high-pitched voice coil bobbin 45 is inserted between the inner diameter of
the voice coil bobbin 8 and the outer diameter of the center pole 4a, and the high-pitched voice
coil 36 is disposed in the second magnetic gap 38, The voice coil bobbin 45 for high sound is
extended upward by projecting the center pole 4a and is held by a high sound damper 46
disposed between the top of the center pole 4a and the inner periphery of the voice coil bobbin
45 for high sound, for high sound A diaphragm 47 for high sound is attached to the end of the
voice coil bobbin 45.
[0041]
Similarly to FIG. 3, the case of FIG. 4 also shows a coaxial two-way speaker, in which the ringshaped drive coil is opposed to the coil 48 at the arrangement position of the high-tone voice coil
36 in the second magnetic gap 38. It is a case of arranging.
In this case, the high sound diaphragm 47 is vibrated by the induced current induced in the high
sound voice coil 36 on the secondary side with respect to the voice current flowing through the
drive coil 49.
That is, it is an electromagnetic induction type speaker.
[0042]
According to the configuration shown in FIGS. 3 and 4, the lower voice coil can be used for highpitched voice, and the upper voice coil can be used for low-mid tone, and the reproduction band
is wider. A coaxially two-way speaker capable of strongly radiating is obtained.
[0043]
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Furthermore, a speaker of another configuration using a short coil similar to that of FIG. 2 of the
present invention will be described with reference to FIG. 5 and FIG.
The case of FIG. 5 is effective when obtaining a small speaker for magnetic shielding, and the
inner diameter formed like a ring is fitted to the step of the magnet guide 4b formed on the disklike portion of the yoke 4 . The ring-shaped drive magnet 3 magnetized to N is joined, and the
ring-shaped first plate 1 is joined onto the drive magnet 3 as well.
Furthermore, in the same diameter as the drive magnet, N. S and the cancel magnet 40
magnetized are joined on the first plate.
Further, a ring-shaped second plate 37 is joined onto the cancel magnet 40, and the outer
diameter portion of the center pole 4a embedded from the center position of the yoke 4 is placed
second above the center pole 4a. A second magnetic gap 38 is formed between the inner
diameter of the plate 37 and the outer diameter of the center pole 4a, and a second magnetic gap
38 is formed between the inner diameter of the first plate 1 and the outer diameter of the center
pole 4a below the center pole 4a. A magnetic gap 17 of 1 is formed.
[0044]
Further, a relatively long voice coil bobbin 40 is inserted into the center pole 4a at a
predetermined interval and held swingably by two upper and lower dampers 9a and 9b to
prevent rolling, and the upper second A voice coil 41 for bass is wound at a corresponding
position of the magnetic gap 38, and a ring of a short coil made of a conductor is disposed in the
lower first magnetic gap 17 to electromagnetically operate the high region. The control is
performed, and the drive magnet 3 and the cancel magnet 40 are covered with a cylindrical
shield cover 43 with a bottom.
[0045]
In this case, the gap length of the upper second magnetic gap 38 is made smaller than the gap
length of the lower first magnetic gap 17, the amount of magnetic flux passing through the
cancel magnet 40 is increased, and the magnetomotive force of the drive magnet 3 is A large one,
which has a small magnetomotive force of the cancel magnet 40, is selected.
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If this structure is adopted, a small-sized speaker having a large magnetic shielding effect and
capable of dumping Q at the resonance of the low resonance frequency f0 can be obtained.
[0046]
The speaker of the configuration shown in FIG. 6 shows another configuration in the case of
obtaining a speaker capable of strong bass radiation by adding the magnetic fluxes of the two
magnets 3 and 40a similarly to the speaker of FIG. The same reference numerals are given to the
corresponding parts and the duplicate description is omitted, but the second magnet 40a stacked
on the first plate 1 is magnetized after the magnetic circuit is assembled in the same direction as
the drive magnet 3 instead of the cancel magnet. It is done.
In this case, since the position of the first plate 1 is approximately the midpoint between the
magnets 3 and 40a, a magnetic flux as shown by φ in the magnetic path passes through the
inner diameter of the first plate 1 and the center pole 4a. The conductive or non-conductive
weight 44 is disposed on the voice coil bobbin corresponding to the position of the first magnetic
gap 17 between the outer diameters of.
In this case, the weight 44 can control the acoustic impedance by adding the mass M and by the
electromagnetic braking effect.
[0047]
It is apparent that the voice coil may be disposed at the short coil ring and weight position in the
configuration of FIGS. 5 and 6 described above.
[0048]
Since the present invention is configured as described above, the driving force is added by the comotion operation of the two voice coils, and the sensitivity and the Q at the resonance of the
lowest low resonance frequency f0 can be reduced. Thus, it is possible to obtain a speaker that is
advantageous for bass radiation.
Further, by using the upper and lower voice coils as coaxial two-way speakers for low to middle
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tones and high tones, it is possible to obtain a small speaker with a wide reproduction band.
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