JPS61219296

Patent Translate
Powered by EPO and Google
Notice
This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
financial decisions, should not be based on machine-translation output.
DESCRIPTION JPS61219296
[0001]
FIELD OF THE INVENTION The present invention relates to an electromagnetic speaker with
reduced leakage flux. 2. Related Art In recent years, the audio industry has been transitioning to
the so-called M era by merging with visual devices, and a large number of magnetically
shielded speakers that do not cause color shift on the screen even when installed next to a
television are commercially available However, the provision of cheaper magnetic shielding
speakers is awaited. Hereinafter, a conventional magnetic shielding speaker will be described
with reference to the drawings. FIG. 2 is a cross-sectional view of a conventional magnetic
shielding speaker. 1 is a yoke, 11L is a center pole portion of the yoke, 2 is a magnet bonded
onto the yoke 1, 3 is a top plate bonded onto the magnet 2, 4 is a magnetic circuit composed of
the above components, 6 Is a frame fixed to the top plate 3, 6 is a gasket, 7 is an edge with one
end adhered to the frame 6, 8 is a diaphragm supported by the edge 7, 9 is a voice coil, and 1o is
a damper for supporting the voice coil Reference numeral 11 denotes a dust cap adhered to the
central portion of the diaphragm 8. Reference numeral 12 denotes a cancel magnet that is
magnetized in the reverse polarity to the magnet 2 and is adhered to the bottom of the yoke, and
13 is a magnetic shielding cover that is adhered to the bottom of the cancel magnet 12. The
operation of the magnetic shielding speaker configured as described above will be described
below. Assuming that there is no temporary magnet 12 and there is no cancel magnet 12 and
only the magnetic shielding cover 13 is coupled, the magnetic flux leaking from the top plate 3 to
the outside is only the one directed to the center pole 1 turtle of the yoke 1. The magnetic flux
leaking from the upper surface and the side surface of the top plate 3 to the bottom surface and
the side surface of the yoke 1 passes through the air shielding cover 13 and hardly leaks to the
outside of the magnetic shielding cover 13. However, in this state, since the magnetic resistance
between the magnetic shielding cover 13 and the bottom surface of the yoke 1 is reduced, the
magnetic flux density of the magnetic gap formed by the center pole portion 1 & and the inner
13-05-2019
1
peripheral surface of the top plate 3 is lowered to deteriorate the efficiency of the speaker. When
the cancel magnet 12 magnetized in reverse polarity is inserted between the magnetic shielding
cover 13 and the bottom of the yoke 1, the magnetic resistance between this and the magnetic
flux apparently appears, and the magnetic flux leaking from the magnetic shielding cover 13 to
the bottom of the yoke 1 almost disappears. Can reduce the efficiency of Problems to be solved
by the invention However, in the configuration as described above, since the cancel magnet 12
and the magnetic shielding cover 13 are fixed to the joke 1 by adhesion, a drying time after
adhesion is required. It had the problem of taking time.
Also, the acrylic adhesive used as an adhesive for these parts is very expensive and has low
thermal conductivity, so the heat dissipation from the heat generated by the voice coil 9 and
transmitted to the yoke 1 is inhibited, and the input resistance of the speaker Also had the
problem of dropping the SUMMARY OF THE INVENTION In view of the above problems, the
present invention provides an inexpensive magnetic shielding speaker without impairing the
input resistance. Means for Solving the Problems In order to solve the above problems, the
magnetic shielding speaker of the present invention is configured to screw and fix the cancel
magnet and the magnetic shielding cover to the yoke. In the present invention, since the
magnetic shielding cover and the cancel magnet are fixed to the joke by the screw according to
the above-described configuration, the step of applying the adhesive and the drying time thereof
are unnecessary, and the manufacturing man-hour can be significantly shortened. It is possible to
reduce the cost because it does not use a common acrylic adhesive. Furthermore, since there is
no adhesive that inhibits thermal conduction between the yoke and the cancel magnet, and
between the cancel magnet and the magnetic shielding cover, the thermal conductivity is good
and the input resistance is not reduced. EXAMPLES The following describes a magnetic shielding
speaker according to an example of the present invention with reference to the drawings. FIG. 1
only shows a cross-sectional view of the magnetic shielding speaker in an embodiment of the
present invention. In FIG. 1, the same parts as in FIG. 2, which is a conventional example, are
assigned the same reference numerals and descriptions thereof will be omitted. The magnetic
shielding cover 13 has a hole at its central portion for passing the screw 14, and the yoke 1 is
provided with a screw hole for the screw 14 to be fitted. The operation of the magnetic shielding
speaker configured as described above will be described with reference to FIG. The operation of
the magnetic shield is completely the same as that of the conventional example, so the
description will be omitted. Since no adhesive is used between the cancel magnet 12 and the
magnetic shielding cover 13, and the space between the cancel magnet 12 and the yoke 1 is also
fixed to the yoke 1 by the screw 14 without using an adhesive, The process is extremely simple
and does not require drying time. Since no expensive adhesive is required, the cost can be
reduced and the heat conductivity is not impeded. As a result, the heat transmitted from the voice
coil 9 to the yoke 1 is efficiently transmitted to the cancel magnet 12 and the magnetic shield
cover 13 As a result, the input resistance can be prevented from decreasing. In the case of fc
using a material with high permeability such as iron for the screw 14, both electrodes of the
13-05-2019
2
cancel magnet 12 are shorted with the screw 14, and as a result, between the center pole portion
1 a and the top plate 3. Although the magnetic flux density will be lowered, if the screw 14 is
made of a material with a low permeability such as brass, the above-mentioned decrease in
magnetic flux density will not occur at all.
Effect of the Invention As described above, according to the present invention, the step of
applying the adhesive and the drying time thereof are unnecessary by fixing the cancel magnet
and the magnetic shielding cover to the yoke with the screw without using the adhesive #)
manufacture Since the number of man-hours can be significantly reduced and expensive
adhesives are not used, the cost can be reduced. Furthermore, since there is no adhesive that
inhibits thermal conduction between the yoke and cancel magnet, and between the cancel
magnet and the magnetic shielding cover, the thermal conductivity is good, and the heat buildup
of the voice coil is reduced, so the input resistance is not reduced. It has an excellent effect.
Furthermore, the use of a low permeability material such as brass for the screw can also prevent
the decrease in magnetic flux density.
[0002]
Brief description of the drawings
[0003]
FIG. 1 is a cross-sectional view of a magnetic shielding speaker in an embodiment of the present
invention, and FIG. 2 is a cross-sectional view of a conventional magnetic shielding speaker.
1 · · · · · · · · · · · · · · · · · · · · · · · Cancel magnet, 13 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·
· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Cancel magnet, 13 · · · · · · · · · · · · · magnetic shielding cover.
Name of Agent Attorney Nakao Toshio One other person Ml Fig. 2, 7! ... yoke 2 ... Mak ° 'net 3 ...
door-to Bua 1-door 4 ··· h story rice 1i Michino 2 - - CEN Yang tJl- Mak' s Component <ゝ 3?
13-05-2019
3

Download Report