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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.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of a conventional small
electromagnetic buzzer, FIG. 2 is a cross-sectional view of a small electromagnetic buzzer
according to an embodiment of the present invention, and FIG. The top view seen from the side,
FIG. 4 is a frequency characteristic comparison figure of the conventional small electromagnetic
buzzer and the small electromagnetic buzzer of this invention. 1
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iron piece, и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и ..... Hootoana, B и и и и и
и open space, C и и и и и и closed space, D и и и и и и open aperture.
DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a small
electromagnetic buzzer, and it is an object of the present invention to reduce the lowest
resonance frequency fo and to improve the sound emission efficiency in the vicinity of 2 Kllz.
Heretofore, this type of small electromagnetic buzzer has generally been formed as shown in FIG.
In the figure, 1 is a permanent magnet, 2 is a yoke, 6 is a coil, 4 is a diaphragm support, 5 is a
diaphragm, 6 is a movable iron piece, 7 is a magnetic pole, 8 is a substrate, 9 is a cover, 10 is an
adhesive , 1-curlose /; / 7 lA is an open space formed by the diaphragm 5 and the cover 9, c is a
diaphragm 5 An enclosed space formed by the moving plate support 4 and the substrate 8 or the
yoke 2. In the above configuration, the magnetic flux from the permanent magnet 1 has a
magnetic circuit composed of the yoke 2, the magnetic pole 7 and the movable iron piece 6, and
the magnetic flux generated by the current flowing through the coil 6 is via the magnetic pole 7
and the yoke 2. The movable iron piece 6 and the diaphragm 5 are vibrated. The vibration sound
of the diaphragm 5 is resonated in the space B and the sound emission hole A, and through the
sound emission hole A ?2> sound emission 15 ? case 0 ? space 8 and sound emission hole? to
constitute a resonator -Efforts were made to make the resonance frequency of this resonator
coincide with the resonance frequency of the diaphragm, but in a small electromagnetic buzzer
having a diaphragm with a diameter of 12 nodes or less, low frequency around 2KH2 Obtaining
the resonance frequency has been extremely difficult, because there is a limit to increasing the
mass of the diaphragm and reducing the thickness. Therefore, for example, in 2048H2, it is
necessary to use the sound pressure at the point a of low sound pressure which is shifted from
the resonance point of the frequency characteristic of the conventional example in FIG. 42-. Also,
the closed space C must be kept constant at all times because the resonant frequency fluctuates
depending on the space capacity, and managing the space capacity manages the volumes of the
magnet 1, the coil 6, and the magnetic pole 7 In order to fix it, for example when using the
adhesive 10, the amount had to be controlled. The air capacity of the enclosed space C is largely
influenced by the above-mentioned fluctuation factor, and has a great influence on the
fluctuation of the resonance frequency, and it is extremely difficult in mass production to make
the air space capacity of the enclosed space C constant. Met. The present invention ameliorates
the above drawbacks, facilitates adjustment of the lowest resonance frequency fo in the vicinity
of 2KH2, improves low frequency characteristics, 2 improves the sound emission efficiency [7
and provides a small electromagnetic buzzer, The contents will be described based on the
illustrated embodiment.
FIG. 2 is a cross-sectional view of one embodiment of the present invention. FIGS. 3-3 are plane
factors viewed from the side of the substrate 8 of FIG. In this embodiment, as shown in FIG. 2 and
FIG. 3: (as shown, an open hole for opening the outside air is provided in the yoke 2 and the
substrate 8 to communicate with the space surrounded by the coil and the permanent magnet
The conventional closed space capacity is communicated with the outside air so that the volume
fluctuation of the parts (magnet 1, coil 6, magnetic pole 7, adhesive 10, etc.) does not become a
factor of the resonance frequency fluctuation. At the same time, in the enclosed space C of FIG. 1,
although the elasticity of the enclosed air acts to increase the stiffness of the diaphragm, the
stiffness is reduced by opening the enclosed space. It is possible to lower the resonance
frequency, for example, to have a resonance frequency even in a diaphragm having a diameter of
12 or less and a low frequency band near 2 KH2. Also, by opening the enclosed space, the air
resistance to the vibrating plate during vibration decreases, and it becomes possible to reduce
the current consumption, and it becomes possible to match the resonance frequency fO around
2KH2, for example A high sound pressure can be obtained with 2048 H 2, and at the same time
it is possible to reduce the current consumption of about 30 chips compared to the case where it
is driven with 2048-12 compared with the one without conventional 2KH 24- The Also, although
the sound pressure is generated only from the sound release hole A in FIG. 1 conventionally,
since the sound can be emitted also from the opposite side, the sound pressure fluctuates
depending on the direction of the sound release hole. "Bz @ tJa, to be extremely low in the
radiation directivity to do, lead to '' i! ?? ? ? ? ? ? и 1 ? Figure 4 shows a comparison of
the frequency characteristics of the prior art and the embodiment of the present invention.
Sound pressure of 74dB and peak current of 30mA in conventional 2048H2) is 82dB and 30yaA
under the same measurement conditions, and the current consumption is lowered to increase the
sound pressure. By providing the open hole, the effect of making the effect is great. This open
hole may be provided in the diaphragm support 4 or the cover 9 without being limited to the
above example, and as long as there is no problem, the larger the better, or a large number may
be provided. Also, the open hole is not limited to the hole, but may be any air gap as long as it
passes through to the outside air, as long as it is larger, the larger the better.
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