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BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
speaker used in various audio equipment.
2. Description of the Related Art Since speakers are mounted on both sides of an electron tube
when they are used in a television receiver, they have conventionally been required to have high
sound quality, miniaturization, low leakage, etc. for televisions. .
Here, a conventional speaker will be described with reference to the cross-sectional view of FIG.
According to the figure, the speaker is provided with a cylindrical first magnet 2 and a hollow
cylindrical yoke 3 provided with a bottom surface surrounding the periphery and a side wall
under a cylindrical top plate 1 in the center, and this yoke 3 A magnetic gap 4 is formed by the
gap between the inner periphery of the top plate 1 and the top plate 1.
A protector 5 sandwiching the outer periphery of the edge portion 8 is provided on the yoke 3,
and the winding portion of the voice coil 6 is set to be positioned at the center of the magnetic
gap 4.
The voice coil 6 is adhesively fixed to the diaphragm 7.
The edge portion 8 of the diaphragm 7 is provided with a flat portion on the outer periphery, and
is adhesively fixed to the yoke 3 and the protector 5.
The operation of the loudspeaker configured as described above will be described below.
The voice coil 6 in the parallel magnetic field located at the center of the magnetic gap 4
generates forces in the vertical direction according to Fleming's left-hand rule, when an electric
voice signal input is applied.
The force is transmitted from the voice coil 6 to the diaphragm 7.
The diaphragm 7 vibrates the air on the front surface to generate a sound.
[Problems to be Solved by the Invention] Conventionally, high sound quality, small size and high
performance, low magnetic leakage, etc. have been required for speakers for televisions, but the
horizontal length of the cathode ray tube, high definition With the development of electronic
devices, low magnetic leakage is required in the miniaturization of speakers.
SUMMARY OF THE INVENTION In order to solve the above problems, the speaker of the present
invention mounts a second magnet, which repels to the first magnet, on the top plate of the first
magnetic circuit, and further comprises a magnetic material. And an equalizer or protector
magnetically coupled to the second magnet at the approximate center and coupled to the first
yoke, the second magnet comprising the second magnet and the magnetic material. The magnetic
circuit is formed to prevent the leakage of the magnetic flux in the forward direction, thereby
achieving a low leakage magnetic flux of the speaker.
BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will
be described below with reference to FIGS. 1 (a) to 3. FIG.
In the description, the same parts as in the prior art will be assigned the same reference
numerals and explanations thereof will be omitted.
(First Embodiment) FIG. 1 (a) is a plan view of a loudspeaker according to an embodiment of the
present invention, FIG. 1 (b) is a sectional view thereof, and FIG. 2 (a) is a loudspeaker according
to the same development example. 2 (b) is a sectional view of the same, FIG. 3 is a plan view of a
speaker according to another development, and FIG. 4 is a plan view of the speaker according to
the other development.
According to FIGS. 1 (a) and 1 (b), 9a is an equalizer made of a magnetic material, such as iron,
having a projecting portion 9b with its center protruding downward inward and having a
bridging portion 9c having a hemispherical cross section. The second magnet 10 is coupled to
the top plate 1 so that the projection 9b of the equalizer 9a is coupled and repelled from the first
magnet 2.
With the above configuration, a repulsive magnetic circuit is formed in which the magnetic flux
moves from the second magnet 10 to the second magnet 10 through the top plate 1 and the
equalizer 9a, and the leakage flux in the forward direction of the speaker is blocked. It is a thing.
In the speaker of the above configuration, the inner periphery of the diaphragm 7 has a
hemispherical shape in cross section coupled to the projecting portion 9b of the equalizer 9a,
thereby becoming a speaker for a tweeter.
2 (a) and 2 (b) show an example of expanding the speaker to a wider band than the above
embodiment, and the equalizer 9a made of a magnetic material has a circular arc shape in cross
section, and the projecting portion 9b in the center is shown. Are coupled to the second magnet
10 coupled to the top plate 1 in the same manner as in FIG. 1 to form a repulsive magnetic
circuit on the top of the speaker.
The diaphragm 7 differs in cross section from that of FIG. 1 in an arc shape to widen the sound
pressure output of the speaker.
3 and 4 are also development examples of the above embodiment, and the difference with the
speaker of FIG. 1 is that the protectors 9d and 9e made of magnetic material are used instead of
the equalizer 9a.
At the central portion of the protectors 9d and 9e, a projecting portion 9b which protrudes
inward and is coupled to the second magnet 10 is provided.
The protector 9d is one in which a large number of small holes are provided by a press or the
like as is apparent from FIG. 3 (partly omitted in FIG. 3), and the protector 9e is formed in a wire
mesh shape (partly in FIG. 4). Is omitted).
As described above, by forming the protectors 9d and 9e and the equalizer 9a of a metallic
magnetic material in the loudspeaker of each of the above-described embodiments, the strength
can be improved even against an external impact.
As described above, according to the present invention, the protector or equalizer covering the
front surface of the speaker is formed of a magnetic material, and a repulsive magnetic circuit is
formed by the second magnet provided inside, thereby leaking the speaker forward. It is possible
to provide a small-sized, low-leakage speaker without preventing the magnetic flux and achieving
the enlargement of the speaker itself.