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Description 1, title of the invention
Electro-acoustic transducer
3. Detailed Description of the Invention The present invention relates to the structure of an
electroacoustic transducer for use in transmitting a sound wave into water or air. The electroacoustic transducer and the end of the line, it is a water heater and a wave transmitter, and it is a
heat container beaker for air. The basic principle is common to all, so the explanation will mainly
be made on the electric wave transmission tube side. Conventionally, as shown in FIG. 1 and FIG.
2 a1 and FIG. 2, electromagnetic type and electric type transmitters are attached to the magnet
3t-case 2 to create a DC magnetic field, and the diaphragm l is placed in this magnetic field. The
signal winding 4 is fixed to one of the diaphragm 1 and the magnet 3. When an alternating
current 1 from the oscillator 5 is allowed to flow through the drive winding 4, the magnitude of
the current is approximately proportional to generate a nine vibration. However, the one in Fig. 1
is suitable for small vibration, and when it vibrates with a large amplitude, the diaphragm is
adsorbed to the magnetoz! There was a downside defect. 2'EndPage: The type shown in Fig. 1
can be vibrated with a large amplitude, but · Fig. 1 is also the same, but complex vibration is
parasitic on the diaphragm support 9 having resilience. There was a drawback. An object of the
present invention is to provide an electro-acoustic transducer which can operate with a large
amplitude and which does not generate complicated parasitic vibration, which solves these
drawbacks. In order to achieve the above object, at least one electroacoustic transducer
according to the present invention? A diaphragm, two magnetic sections at least one of which
moves with the diaphragm and is disposed facing each other, a case for housing the two
magnetic sections, and a magnetic section interlocking with the diaphragm can be slid along the
case circle And supporting means for supporting the magnetic field, means for generating a
magnetic field which causes the two magnetic parts to emit reciprocally, and means for supplying
a signal current to at least one of the two magnetic parts. And Next, an embodiment of the
present invention will be described with reference to the drawings. FIG. 3 shows a first
embodiment, in which the diaphragm IK drive winding 4 is fixed, and further, the magne is
assembled under it and is referred to as a diaphragm assembly). It is fitted through 0 ring jacket
as 10. In the bottom of the case, another magnet 3 is fixedly attached, and a pressure reducing
valve 6 is provided near the bottom of the case. The above i-gnets 3 and 3 'are flat plates having
smooth surfaces and magnetized in the thickness direction, and each of the six is opposed in a
repelling direction. Thus, the magnet 3 'is held empty and balanced with the weight of the
diaphragm assembly. However, the diaphragm 1 needs to be supported so as not to protrude
outside the case, and it must be supported so softly that it does not cause complicated vibrations.
Therefore, a vacuum pump is connected to the pressure reducing pulp 6 to reduce the pressure
inside the case 2 by the IE pressure. Although the diaphragm support portion 10 is considered to
be a flat plate of rubber, etc., since the 0 ring jacket hardly hinders the piston movement of the
diaphragm, the diaphragm assembly is attracted to the case side and the magnet interval d is
narrow. Balance at intervals. D is a means for narrowing the required amplitude of vibration to a
distance close to 2 °, but is an effective means for enhancing the electroacoustic conversion
efficiency. Although this pressure reduction is not essential, it is an excellent means to support
the diaphragm assembly in the hollow state. Next, the operation when the oscillator 5 is
connected to the drive winding 4 and an alternating current flows is described. When an
alternating current is caused to flow through the signal winding 4, a countercurrent magnetic
field is generated in the axial direction of the diaphragm accordingly, and the DC magnetic field
of the magnet 3 'is superimposed to increase or decrease the magnetic field. As a result, the
diaphragm assembly is more repelled or attracted from the initial resting position, and vibrates in
response to the alternating current, and emits sound waves from the outer surface of the
diaphragm. Magnets are ferrites with little loss for AC magnetic fields! Gnet is advantageous.
According to this structure, since the driving force and the restoring force are applied to almost
the entire surface of the diaphragm, the occurrence of parasitic vibration is reduced and a
desired vibration can be obtained. Another characteristic is that the recovery force by this
method is a simple elastic body when viewed from the diaphragm, and one having a high
compliance can be easily manufactured with a low resonance frequency. -The above description
is a transmitter of a structure in which sound is emitted from one side of case 20, but as shown
in FIG. 3 (a transmission 5 of a structure in which a compression wave of the same phase is
radiated from both sides of frame 2 as shown in bl). Is obtained. This double-sided radiation
structure is advantageous when omnidirectionality is required, and since the radiation impedance
can be high, the radiation efficiency is high) and the utility value is high. FIG. 4 is a second
embodiment of the present invention. The principle is the same as that of the first embodiment,
but both magnets 1 (which are replaced by coils, so that a direct current turtle current is made to
flow by the DC power source 7 so as to generate a repulsive magnetic field. Coils are
advantageous in making transducers that use high frequencies as well because they are easy to
lighten the mass of the magnet. The example 1i shows the case where the DC magnetic field coil
and the drive winding are shared. In this case, since the driving force is next to both magnetic
fields, the frequency of the driving force is twice the frequency of the current. Therefore, when
used at the resonance frequency, the signal 12 · current needs to be the frequency of i at the
resonance frequency.
EndPage: 2 It is natural that only one side of this example is a magnet, the current frequency in
this case is the vibration frequency. In the figure, 5 is an oscillator and 8 is a decoupling
capacitor. The present invention, as described above, constitutes a pair of mutually repelling DC
magnetic fields, and by combining the diaphragm with the space without using a mechanical
elastic body, there is less parasitic vibration and low frequency. A transmitter that resonates at is
obtained. In addition, this structure has the following advantages when used as a speaker. (1) As
described above, since the resonance frequency can be increased, a wide band frequency
characteristic can be obtained. (2) Usually, the speaker covers the back of the diaphragm with a
case, and a sound absorbing material is placed inside to prevent the air inside the case from
resonating or vibrating the box through the air. Also, the dimensions of the case are extremely
large in order to avoid reaction of air in the case, but according to the structure of the present
invention, the pressure inside the case is low, so reaction is small and there is no sound
absorbing material even though it is small. The resonance can also be suppressed low.
4. Brief description of the drawings FIGS. 1 and 2 are cross-sectional views of conventional
electromagnetic and electric wave transmitters, and FIGS. 3 (a), 3 (b) and 4 are embodiments of
the present invention. It is each sectional view showing. 1.1 '· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·
· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · motor winding, ··· Oscillator · · · · · · ·
· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · • Attorney Attorney Attorney Uchihara (7 ',' j: '-') EndPage: 3