JP2005073059

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 JP2005073059
The present invention provides an electromagnetic transducer and an acoustic radiation device
having improved frequency characteristics and strain rate characteristics by eliminating
resonance of components. A coil (17) is wound around an outer peripheral surface of a
cylindrical portion (190) of a bobbin (19), and a magnetostrictive element (11) is inserted inside.
The magnetostrictive element 11 is received by the bottom 42 at one end. The permanent
magnets 13 and 15 apply a magnetic bias to the magnetostrictive element 11. One end side of
the expansion / contraction transmission member 5 is connected to the other end side of the
magnetostrictive element 11, and the other end is led to the outside through the opening 411 of
the exterior body 4. The pressurizing member 6 is made of an elastic material containing a
polymer material as a main component, and is interposed between the exterior body 4 and the
expansion / contraction transmission member 5 to bias the expansion / contraction transmission
member 5 in the direction of the magnetostrictive element 11. [Selected figure] Figure 1
Electromagnetic converter for acoustic radiation device and acoustic radiation device
[0001]
The present invention relates to an electromagnetic transducer for an acoustic radiation device
and an acoustic radiation device using the same.
[0002]
In this type of acoustic radiation apparatus, an input signal is applied to a coil wound around a
cylindrical portion of a bobbin to cause expansion / contraction vibration in the magnetostrictive
element, and the expansion / contraction vibration is directly or indirectly applied to the
expansion / contraction end of the magnetostrictive element. The sound is generated by
04-05-2019
1
transmitting to the diaphragm through the component parts that are in contact with each other,
and generally used as a speaker.
[0003]
In the above-described acoustic radiation device, when an acoustic resonance caused by the
expansion and contraction (vibration) of the magnetostrictive element occurs in a component in
contact with the expansion and contraction end of the magnetostrictive element, the vibration
(resonance) other than the input signal is transmitted to the diaphragm. Since it is transmitted
and causes deterioration of frequency characteristics and distortion characteristics, acoustic
resonance must be suppressed.
[0004]
In particular, this type of acoustic radiation device requires a pressure member for applying a
pressure to the magnetostrictive element, so that the acoustic resonance phenomenon in the
pressure member must be avoided.
When a material such as metal having strong resonance in the audio frequency band is used for
the pressure member, the vibration of the magnetostrictive element is transmitted to the
pressure member, resonance occurs in the pressure member, and vibrations other than the input
signal are vibration. It is transmitted to the plate, which causes deterioration of the frequency
characteristic and the distortion characteristic.
[0005]
Patent Document 1 discloses a structure in which a plate spring is interposed as a pressurizing
member between an actuator rod (a magnetostrictive expansion transmission member)
connected to an expansion end of a magnetostrictive rod and an outer cylinder.
However, the leaf spring that constitutes the pressurizing member is made of a metal material,
and there is no description about the frequency characteristics and distortion factor
characteristics when using a metal material for the pressurizing member.
04-05-2019
2
[0006]
Further, the vibration drive device disclosed in Patent Document 2 has a configuration in which
the stretchable end of the magnetostrictive stretch transmission member is directly coupled to
the vibrator for sound generation, and means for reducing acoustic noise due to resonance is
disclosed. It has not been.
Japanese Patent Application Laid-Open No. 10-145892 Japanese Patent Application Laid-open
No. 4-1313998
[0007]
An object of the present invention is to provide an electromagnetic transducer and an acoustic
radiation device for an acoustic radiation device having improved frequency characteristics and
strain rate characteristics by eliminating resonance of components.
[0008]
Another object of the present invention is to provide an electromagnetic conversion device and
an acoustic radiation device for an acoustic radiation device that can reduce stress on the
magnetostrictive device and suppress aging of the device strength by eliminating resonance of
components. It is to be.
[0009]
In order to solve the problems described above, the present invention discloses an
electromagnetic conversion device and an acoustic radiation device for an acoustic radiation
device.
[0010]
1.
Electromagnetic Converter for Acoustic Radiation Device The electromagnetic transducer for
acoustic radiation device according to the present invention includes an exterior body, a bobbin,
a coil, a magnetostrictive element, a permanent magnet, an expansion / contraction transmission
04-05-2019
3
member, and a pressure member.
[0011]
The exterior body has an internal space and a bottom, and one end of the internal space is closed
by the bottom and has an opening on the other side facing the bottom.
The bobbin, the coil, the magnetostrictive element, the permanent magnet, the expansion /
contraction transmission member, and the pressure member are accommodated in the internal
space of the exterior body.
[0012]
The bobbin has a cylindrical portion, and the coil is wound around the outer peripheral surface
of the cylindrical portion of the bobbin.
[0013]
The magnetostrictive element is inserted into the cylindrical portion of the bobbin, and one end
of the opposite ends is received by the bottom portion of the exterior body.
The permanent magnet applies a magnetic bias to the magnetostrictive element.
One end side of the expansion / contraction transmission member is connected to the other end
side of the magnetostrictive element, and the other end is led to the outside through the opening.
[0014]
The pressurizing member is made of an elastic material containing a polymer material as a main
component, and is interposed between the exterior body and the expansion / contraction
transmission member, and biases the expansion / contraction transmission member in the
direction of the magnetostrictive element.
04-05-2019
4
[0015]
In the above-described electromagnetic transducer for an acoustic radiation device according to
the present invention, components such as an expansion / contraction transmission member, a
pressure member, a magnetostrictive element, a permanent magnet, a coil and a bobbin are
accommodated in the internal space of the exterior The whole can be protected by the exterior
body.
[0016]
The sheath has a bottom, and the magnetostrictive element is received at one end of the opposite
ends by the bottom of the sheath.
One end of the expansion / contraction transmission member is connected to the other end of
the magnetostrictive element.
The pressurizing member is made of an elastic material and is interposed between the outer
package and the expansion / contraction transmission member, and presses the expansion /
contraction transmission member against the magnetostrictive element. Therefore, the
pressurization can be applied to the magnetostrictive element from the pressurization member
via the expansion / contraction transmission member.
[0017]
In addition, the coil is wound around the outer peripheral surface of the cylindrical portion of the
bobbin, and the magnetostrictive element is inserted inside the cylindrical portion of the bobbin.
A magnetic bias from a permanent magnet is applied to the magnetostrictive element. Therefore,
when an AC input signal is applied to the coil, expansion and contraction vibration corresponding
to the AC input signal is generated in the magnetostrictive element. The expansion and
contraction vibration of the magnetostrictive element is transmitted to the expansion and
contraction transmission member, and the expansion and contraction transmission member
vibrates by receiving the expansion and contraction vibration of the magnetostrictive element.
[0018]
04-05-2019
5
Since the magnetostrictive element is inserted inside the tubular portion of the bobbin and the
coil is wound around the outer peripheral surface of the tubular portion of the bobbin, the
bobbin prevents deterioration and damage of the coil due to the stretching vibration of the
magnetostrictive element by the bobbin Can.
[0019]
Furthermore, the interior space of the exterior body has an opening on the side facing the bottom
of the exterior body, and the expansion / contraction transmission member has the other end
guided to the outside through the opening of the exterior body. The vibration output of the
member can be taken outside.
[0020]
In the structure of the electromagnetic transducer for the acoustic radiation device, since the
pressure member is made of an elastic material mainly composed of a polymer material, the
pressure member does not generate strong resonance vibration in the audio frequency band. .
For this reason, it is possible to avoid the resonance of the pressurizing member due to the
expansion and contraction vibration of the magnetostrictive element.
Therefore, the generation of the vibration not depending on the input signal is suppressed, the
acoustic noise due to the resonance can be reduced, and the frequency characteristic and the
distortion factor characteristic can be improved.
[0021]
In addition, since strong resonance vibration is not generated in the pressurizing member, stress
on the magnetostrictive element can be reduced, and deterioration over time of the
magnetostrictive element strength can be suppressed.
[0022]
2.
04-05-2019
6
Acoustic radiation apparatus The acoustic radiation apparatus according to the present invention
includes an electromagnetic transducer for acoustic radiation apparatus and a diaphragm. The
electromagnetic transducer for acoustic radiation device is the electromagnetic transducer for
acoustic radiation device according to the present invention described above. The diaphragm is
connected to the expansion / contraction transmission member.
[0023]
The acoustic radiation device according to the present invention uses the above-described
electromagnetic transducer for the acoustic radiation device according to the present invention,
so that the operation and effect of the electromagnetic transducer for the acoustic radiation
device according to the present invention can be obtained as it is.
[0024]
As described above, according to the present invention, the following effects can be obtained.
[0025]
(A) By eliminating the resonance of the component parts, it is possible to provide an
electromagnetic conversion device and an acoustic radiation device with improved frequency
characteristics and distortion factor characteristics.
[0026]
(B) By eliminating the resonance of the component parts, it is possible to provide the
electromagnetic transducer for acoustic radiation device and the acoustic radiation device
capable of reducing the stress on the magnetostrictive element and suppressing the temporal
deterioration of the element strength.
[0027]
1.
FIG. 1 is a front sectional view of an electromagnetic converter for an acoustic radiation device
according to the present invention, and FIG. 2 is an exploded sectional view of the
electromagnetic converter for an acoustic radiation device shown in FIG.
04-05-2019
7
The illustrated electromagnetic transducer for an acoustic radiation device includes an exterior
body 4, an expansion / contraction transmission member 5, a pressure application member 6, a
magnetostrictive element 11, permanent magnets 13 and 15, a coil 17, and a bobbin 19. .
[0028]
The exterior body 4 is made of a rigid material such as a metal material, and has an internal
space 415 and a bottom 42.
The exterior body 4 has a structure in which a bottom portion 42 is fitted into one end of a
cylindrical portion 41 and fixed by a fastener 45 such as a screw, and has an opening 411 on the
side opposite to the bottom portion 42 .
The opening 411 has an inward flange 412 formed at the other end of the cylindrical portion 41.
The expansion / contraction transmission member 5, the pressure member 6, the
magnetostrictive element 11, the permanent magnets 13 and 15, the coil 17 and the bobbin 19
are accommodated in the internal space 415 of the exterior body 4.
[0029]
The bobbin 19 has a cylindrical portion 190, and the coil 17 is wound around the outer
peripheral surface of the cylindrical portion 190 of the bobbin 19. The magnetostrictive element
11 is inserted into the cylindrical portion 190 of the bobbin 19. The magnetostrictive element 11
has one end received by the bottom portion 42 at the opposite ends. The illustrated
magnetostrictive element 11 is rod-shaped, and permanent magnets 13 and 15 are provided at
both ends thereof. The permanent magnets 13 and 15 apply a magnetic bias to the
magnetostrictive element 11.
[0030]
Collars 191 and 192 are provided at both ends of the bobbin 19, and the permanent magnets 13
04-05-2019
8
and 15 are positioned in recesses provided on the outer surfaces of the collars 191 and 192 of
the bobbin 19. The permanent magnet 15 and the flanges 191 and 192 of the bobbin 19 are
fitted into the steps 421 and 423 provided on the inner surface of the bottom 42.
[0031]
One end side of the expansion / contraction transmission member 5 is directly or indirectly
connected to the other end side of the magnetostrictive element 11, and the other end is led to
the outside through the opening 411. The expansion / contraction transmission member 5 is
preferably made of a material containing a polymer material as a main component. The
illustrated expansion / contraction transmission member 5 has a hollow portion 51 on the
receiving side of the magnetostrictive element 11. The inner bottom surface of the hollow
portion 51 is provided with a recess 53 for receiving the permanent magnet 13. The trunk
portion 54 of the expansion / contraction transmission member 5 has a stepped shape, and a
screw portion 55 is provided at a leading end portion which is led to the outside. A flange 52 is
provided at the rear end of the body 54.
[0032]
The pressurizing member 6 is made of an elastic material containing a polymer material as a
main component, and is interposed between the exterior body 4 and the expansion / contraction
transmission member 5 to bias the expansion / contraction transmission member 5 in the
direction of the magnetostrictive element 11. A preferred material for constructing the pressureapplying member 6 is polymer rubber or polymer plastic having a certain elastic modulus. It may
be a single material of a polymer material, or may be a composite material in which an inorganic
powder or the like is added to the polymer material. Conventionally, metal flat springs or metal
coil springs have been used as pressure members, but in the present invention, conventional
metal springs are changed to elastic materials mainly composed of the above-described polymer
material. It is The pressurizing member 6 of the embodiment has a cylindrical shape, and one end
seen in the axial direction of the cylindrical body is received by the exterior body 4, and the other
end is formed by the flange portion 52 of the expansion and contraction transmitting member 5.
Received by
[0033]
The pressurizing member 6 is disposed so as to surround the body 54 of the expansion /
contraction transmission member 5 and includes a step 56 constituted by a flange 52 provided
04-05-2019
9
at an end of the body 54 and a flange 72 of the spacer 7. It is compressed between the steps 73.
[0034]
In the illustrated embodiment, the spacer 7 is included, and the spacer 7 is inserted between the
exterior body 4 and the stretch transmission member 5.
The spacer 7 is also preferably made of a material containing a polymer material as a main
component. The spacer 7 has a collar 72, which overlaps the inner surface 413 of the inward
collar 412 of the sheath 4 and is supported thereby.
[0035]
In the electromagnetic conversion device according to the present invention described above, the
expansion / contraction transmission member 5, the pressure member 6, the magnetostrictive
element 11, the permanent magnets 13 and 15, the coil 17 and the bobbin 19 are
accommodated in the internal space 415 of the exterior body 4. Therefore, the whole can be
protected by the exterior body 4.
[0036]
The exterior body 4 has a bottom 42, and one end of the opposite ends of the magnetostrictive
element 11 is received by the bottom 42.
One end side of the expansion / contraction transmission member 5 is connected to the other
end side of the magnetostrictive element 11. The pressure member 6 is interposed between the
exterior body 4 and the expansion / contraction transmission member 5 and biases the
expansion / contraction transmission member 5 in the direction of the magnetostrictive element
11. Therefore, the pressurization can be applied to the magnetostrictive element 11 from the
pressurization member 6 through the expansion / contraction transmission member 5.
[0037]
04-05-2019
10
As shown in an exploded manner in FIG. 2, the pressurizing member 6 of the embodiment has a
length L0 in the non-compressed state, but in the assembled state in FIG. Between the step
portion 56 and the step portion 73 of the flange portion 72 of the spacer 7, the position P0 is
compressed by the compression amount ΔL from the position P1 (see FIG. 2) to a length L1
smaller than the length L0 . As a result, the preload F is applied to the magnetostrictive element
11.
[0038]
The coil 17 is wound around the outer peripheral surface of the cylindrical portion 190 of the
bobbin 19, and the magnetostrictive element 11 is inserted into the cylindrical portion 190 of
the bobbin 19. A magnetic bias from the permanent magnets 13 and 15 is applied to the
magnetostrictive element 11. Therefore, when an alternating current input signal is applied to
the coil 17, stretching vibration according to the input signal is generated in the magnetostrictive
element 11, and the stretching transmission member 5 is driven by receiving the stretching
vibration of the magnetostrictive element 11 and vibrates.
[0039]
The magnetostrictive element 11 is inserted inside the cylindrical portion 190 of the bobbin 19,
and the coil 17 is wound around the outer peripheral surface of the cylindrical portion 190 of
the bobbin 19. Degradation and damage can be prevented by the bobbin 19.
[0040]
The internal space 415 of the exterior body 4 has an opening 411 on the side facing the bottom
42, and the other end of the expansion / contraction transmission member 5 is led to the outside
through the opening 411 of the exterior body 4, The vibration output of the expansion /
contraction transmission member 5 can be taken out to the outside.
[0041]
In the structure of such an electromagnetic transducer, since the pressure member 6 is made of
an elastic material mainly composed of a polymer material, the pressure member 6 does not
generate strong resonance vibration in the audio frequency band.
04-05-2019
11
Therefore, the resonance of the pressurizing member 6 due to the expansion and contraction
vibration of the magnetostrictive element 11 can be avoided.
Therefore, it is possible to suppress the generation of the vibration independent of the input
signal, reduce the acoustic noise, and improve the frequency characteristic and the distortion
factor characteristic.
[0042]
Further, since strong resonance vibration is not generated in the pressurizing member 6, stress
on the magnetostrictive element 11 can be reduced, and deterioration in strength of the
magnetostrictive element 11 with time can be suppressed.
[0043]
In the embodiment in which not only the pressurizing member 6 but also the expansion
transmission member 5 and the spacer are made of a material mainly composed of a polymer
material, between the expansion end side of the magnetostrictive element 11 and the exterior
body 4 For all components that are directly and indirectly coupled to, no strong resonant
vibrations occur in the audio frequency band.
Therefore, the generation of vibrations other than the input signal can be suppressed more
completely, and further excellent frequency characteristics and distortion factor characteristics
can be obtained.
[0044]
Furthermore, according to the embodiment in which the spacer 7 inserted between the exterior
body 4 and the expansion / contraction transmission member 5 is made of a polymer material,
the vibration due to the expansion / contraction of the magnetostrictive element 11 causes the
expansion / contraction transmission member 5 and the spacer 7 Since it is transmitted to the
exterior body 4 through the resonance, the resonance of the exterior body 4 itself can be
suppressed.
[0045]
04-05-2019
12
2.
Acoustic Radiation Device FIG. 3 is a partial cross-sectional view of an acoustic radiation device
according to the present invention. In the figure, the same reference numerals are given to the
same components as the components shown in FIG. 1 and FIG. The illustrated acoustic radiation
device comprises an electromagnetic transducer 9 according to the invention as illustrated and
described in FIGS. 1 and 2 and a diaphragm 10. The diaphragm 10 is connected to the expansion
/ contraction transmission member 5 of the electromagnetic conversion device 9. In the
illustrated embodiment, the diaphragm 10 is driven by the pressing member 83 screwed to the
tip of the expansion / contraction transmission member 5.
[0046]
Since the acoustic radiation device shown in FIG. 3 uses the electromagnetic transducer 9 for
acoustic radiation device according to the present invention, all the above-described effects of the
electromagnetic transducer 9 for acoustic radiation device can be obtained. That is, since the
resonance of the component parts of the electromagnetic conversion device 9 is eliminated, it is
possible to obtain an acoustic radiation device having improved frequency characteristics and
distortion characteristics. In addition, it is possible to obtain an acoustic radiation device capable
of reducing the stress on the magnetostrictive element 11 and suppressing the temporal
deterioration of the element strength.
[0047]
FIG. 4 is a sound pressure-frequency characteristic diagram of a conventional acoustic radiation
device using a metal coil spring as the pressurizing member 6, and FIG. 5 is a sound pressurefrequency characteristic diagram of the acoustic radiation device according to the present
invention.
[0048]
Referring to FIG. 4, in the conventional acoustic radiation device using a metal coil spring, a peak
point C11 occurs due to the resonance of the metal coil spring around an audio frequency 8000
Hz, and a dip point C12 occurs around an audio frequency 10000 Hz.
[0049]
04-05-2019
13
On the other hand, in the acoustic radiation device using the electromagnetic conversion device 9
according to the present invention, it is understood that the resonance point disappears, and the
resonance of the pressurizing member 6 which is a component part is eliminated.
[0050]
Although the contents of the present invention have been described above with reference to the
accompanying drawings which are examples, it is obvious that the present invention is not
limited to these examples.
[0051]
It is front sectional drawing of the electromagnetic transducer for acoustic radiation apparatuses
which concerns on this invention.
It is a disassembled sectional view of an electromagnetic transducer for acoustic radiation
devices shown in FIG.
1 is a partial cross-sectional view of an acoustic radiation device according to the present
invention.
It is a sound pressure-frequency-characteristics figure of the conventional acoustic radiation
apparatus which used the metal coil spring as a pressurizing member.
It is a sound pressure-frequency characteristic view of an acoustic radiation device concerning
the present invention.
Explanation of sign
[0052]
DESCRIPTION OF SYMBOLS 4 exterior body 5 expansion-contraction transmission member 6
pressurization member 7 spacer 13, 15 permanent magnet 11 magnetostrictive element 17 coil
19 bobbin
04-05-2019
14
04-05-2019
15