close

Вход

Забыли?

вход по аккаунту

?

JP2015186102

код для вставкиСкачать
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 JP2015186102
Abstract: [Problem] To provide a bone conduction device capable of high output even in a small
size and light weight. A bottomed cylindrical main body 2 made of a magnetic material is
provided with a peripheral wall 2c which is open at the upper end and surrounds the whole
circumference of the opening, and a diaphragm 3 is provided across the opening 2a of the
cylindrical main body 2. And a magnet 5 fixed to the lower surface 3 c side of the diaphragm 3
and at least a part of which is located in the cylindrical main body 2 below the position of the
upper end opening of the cylindrical main body 2; The yoke 4 is provided upright on the 2b, and
the upper end face 4a is opposed to the lower end face 5b of the magnet 5 with a gap, and the
voice coil 6 disposed around the yoke 4 in the cylindrical main body 2. [Selected figure] Figure 2
Bone conduction device
[0001]
The present invention relates to a bone conduction device suitably used as a vibration driver for
a bone conduction speaker or a microphone, and more particularly to an efficient bone
conduction device capable of high output even in a small size and light weight.
[0002]
Conventionally, as a bone conduction device of this type, as disclosed in, for example, FIG. 1 of
Patent Document 1, an extension (30) (30 ') for supporting a diaphragm (70) is provided, and a
voice coil (40) is provided. And the central magnetic pole (yoke) (50), and the diaphragm (70) on
the upper part of which the iron piece (60) is fixed is extended between the extension parts (30)
03-05-2019
1
and (30 '). A structure having a magnet (90) attached to the top is provided.
This structure simplifies the assembly process and reduces costs, and because the magnet is
located not on the outer periphery of the voice coil but on the top of the diaphragm, the size and
the like of the voice coil can be changed relatively freely. The range of adjustment is broadened,
and the overall size and weight of the device can be reduced.
[0003]
However, according to the structure of the bone conduction device of Patent Document 1, there
is no magnet on the outer peripheral side of the voice coil, and the whole can be slimmed, and
the width and design of adjustment of characteristics of the voice coil and the magnet The degree
of freedom also increases, but there has been a certain limit to the increase in output.
[0004]
JP 2007-74693 A
[0005]
Therefore, in view of the above-described situation, the present invention is to provide a bone
conduction device capable of high output even with small size and light weight.
[0006]
As a result of intensive studies conducted by the inventor in view of the present situation, the
present inventors have studied the upper part where the magnet is on the opposite side to the
voice coil with respect to the diaphragm as the cause of the limitation of the output increase of
the bone conduction device of Patent Document 1 above. Fixed, which causes magnetic leakage
and leads to inefficiency of the magnetic circuit, as well as the structure of the case with the yoke
disturbs the magnetic circuit and makes the flow of magnetic flux non-uniform, likewise the
magnetic It has been found that leakage, saturation of magnetic flux, and inefficiency of the
magnetic circuit are caused, and the present invention has been completed.
[0007]
That is, according to the present invention, a bottomed cylindrical main body made of a magnetic
material having a peripheral wall whose upper end is open and which surrounds the whole
circumference, a diaphragm which is provided across the opening of the cylindrical main body, A
magnet fixed to the lower surface side of the diaphragm and at least a part of which is at least
03-05-2019
2
partially located within the cylindrical main body below the position of the upper end opening of
the cylindrical main body, and erected on the inner bottom surface of the cylindrical main body
The present invention provides a bone conduction device comprising a yoke opposed to the
lower end face of the magnet with a gap and a voice coil disposed around the yoke in the
cylindrical main body.
[0008]
Here, the cylindrical main body is formed of a magnetic material, and is formed of a bottomed
inner cylindrical portion provided with a circumferential wall covering the entire circumference
and a nonmagnetic material, and provided on the outer peripheral surface side of the inner
cylindrical portion. And what comprises an outer side covering part provided with the fixed part
which fixes the above-mentioned diaphragm is preferred.
[0009]
According to the bone conduction device of the present invention as described above, most of the
magnetic flux from the upper surface side of the magnet fixed to the lower surface side of the
diaphragm is dissipated to the outside from the opening of the cylindrical main body. Instead, it
is efficiently captured by the upper end of the cylindrical main body peripheral wall surrounding
the opening over the entire circumference, and is guided to the yoke and the magnet through the
cylindrical main body.
The direction of the magnetic flux is not limited, and vice versa.
That is, according to the present invention, an efficient magnetic circuit in which the flow of
magnetic flux is uniform and compact is formed, and the magnetic leakage to the outside is
extremely reduced. In addition to the effects that the width of adjustment of characteristics and
the degree of freedom of design increase, it becomes highly efficient, and it becomes possible to
obtain high output even if it is compact and lightweight.
[0010]
Further, the cylindrical main body is formed of a magnetic material and is formed of a bottomed
inner cylindrical portion having a circumferential wall extending all around, and a nonmagnetic
material, provided on the outer peripheral surface side of the inner cylindrical portion and Since
it is composed of an outer covering portion provided with a fixing portion for fixing the
03-05-2019
3
diaphragm, there is no need to provide a fixing portion having a complicated shape on the inner
cylindrical portion to be a magnetic circuit. It is possible to make the shape and structure as
simple as possible without causing the disturbance of the magnetic flux, uniform the flow of the
magnetic flux, prevent the magnetic leakage, and further pursue the improvement of efficiency
and output.
[0011]
1 is a perspective view of a bone conduction device according to a representative embodiment of
the present invention.
Similarly, a longitudinal sectional view of a bone conduction device.
The same exploded perspective view.
Explanatory drawing which shows the structure of the model of the comparative example 2. FIG.
Explanatory drawing which shows the structure of the model of the comparative example 3. FIG.
The simulation result of the magnetic flux density distribution of Example 1. FIG. The simulation
result of the magnetic flux density distribution of the comparative example 1. The simulation
result of the magnetic flux density distribution of the comparative example 2. The simulation
result of the magnetic flux density distribution of the comparative example 3.
[0012]
Next, an embodiment of the present invention will be described in detail with reference to the
attached drawings.
[0013]
The bone conduction device 1 according to the present invention is, as shown in FIGS. 1 to 3, a
bottomed cylindrical main body 2 made of a magnetic material having a peripheral wall 2c which
is open at the upper end and surrounds the opening over the entire circumference; The
03-05-2019
4
diaphragm 3 provided at the opening 2a of the cylindrical main body 2 and the lower surface 3c
of the diaphragm 3 are fixed to the lower surface 3c of the cylindrical main body 2 at least
partially 2 and a yoke 4 which is erected on the inner bottom surface 2b of the cylindrical main
body 2 and whose upper end face 4a is opposed to the lower end face 5b of the magnet 5 with a
gap, yokes in the cylindrical main body 2 It comprises a voice coil 6 disposed around four.
[0014]
The cylindrical main body 2 is a bottomed case in which the yoke 4, the magnet 5 and the voice
coil 6 are disposed inside, and the inner cylindrical portion 20 formed of a magnetic material and
the outer covering portion 21 formed of a nonmagnetic material And consists of.
Then, by providing the fixing portion for fixing the diaphragm 3 to the outer covering portion 21
of the nonmagnetic body and making the inner cylindrical portion 20 of the magnetic body into a
simple cylindrical body having no such complicated structure, The magnetic flux from the
magnet can be uniformly and efficiently introduced through the inner cylindrical portion 20
without being disturbed.
[0015]
The inner cylindrical portion 20 is a bottomed cylindrical body provided with a peripheral wall
24 extending over the entire circumference, which makes a part of the peripheral wall 2c, and is
formed by pressing a magnetic metal, for example, a stainless steel of SUS430. .
The position of the upper end of the peripheral wall 24 of the inner cylindrical portion 20 is
substantially the same height over the entire circumference. The magnetic flux from the upper
surface side of the magnet 5 tries to spread in all directions in the periphery, but can be
efficiently captured by the peripheral wall 24 surrounding most of the periphery at substantially
the same height over the entire periphery, Leakage can be extremely reduced.
[0016]
Further, the peripheral wall 24 has a substantially uniform thickness over the entire
03-05-2019
5
circumference, and in the present example, at least the inner peripheral surface of the peripheral
wall 24 is a continuous curved surface without corners in a plan view viewed from the upper
side, particularly substantially circular (this example In this case, the cylindrical body is a true
circular shape, and there is no notch or hole on the entire surface of the peripheral wall 24, and
the uniform thickness and uniform height are provided over the entire circumference. Therefore,
the inner cylindrical portion 20 forms a uniform and efficient magnetic circuit in the
circumferential direction. It is also preferable to have a substantially elliptical shape in plan view.
However, although the uniformity is lowered, it may of course be a quadrangle or other
polygonal or irregular shape, and a notch or a hole may be formed in part of the peripheral wall.
[0017]
At the central portion of the bottom wall 25 of the inner cylindrical portion 20, a throughattached mounting hole 20c for fixing the yoke 4 made of a magnetic material is bored. Then, a
substantially cylindrical yoke 4 is fixed by caulking the bottom to the mounting hole 20c. Of
course, the yoke 4 may be erected on the bottom wall 25 by another fixing method such as
welding. Further, instead of fixing the yoke 4 separately formed as in this example, it may be
integrally formed with the cylindrical main body 2 (inner cylindrical portion 20) by shaving or
casting.
[0018]
The outer covering portion 21 is provided on the outer surface side of the inner cylindrical
portion 20 and has a fixing portion 23 for fixing the diaphragm 3. Specifically, the same
bottomed cylindrical portion is insert-molded on the outer surface side of the inner cylindrical
portion 20 using a synthetic resin material, and a plurality of flanges are provided protrudingly
as the fixing portion 23 on the upper outer peripheral portion. The diaphragm 3 is bridged
between the upper surfaces of the flanges (fixing portions 23).
[0019]
The formation of the outer covering portion 21 is performed in a state in which the yoke 4 is
crimped to the bottom surface of the inner cylindrical portion 20 in advance as described above.
Therefore, the caulking portion of the yoke 4 projecting downward from the mounting hole 20c
of the inner cylindrical portion 20 is also buried in the synthetic resin constituting the outer
03-05-2019
6
covering portion 21, and the assembling strength of the yoke 4 is improved.
[0020]
In this example, as in the case of the inner cylindrical portion 20, although it is a bottomed
cylindrical shape having a peripheral wall 26 covering the entire circumference that makes a part
of the peripheral wall 2c, it is not limited thereto. The one having a wall or the one having a
cylindrical shape may be coated only on the upper end side where the flange (fixing portion 23)
is formed. Since the outer covering portion 21 does not constitute a magnetic circuit, it does not
affect the reduction of magnetic leakage and the improvement of the efficiency even if the
peripheral wall 24 is the same as the peripheral wall 24 of the inner cylindrical portion 20.
Further, not limited to the insert molding, for example, a member formed into a cylindrical shape
separately from the synthetic resin as the outer covering portion 21 may be assembled to the
outside of the inner cylindrical portion 20.
[0021]
The diaphragm 3 has an annular frame portion 30 fixed by an attachment screw 7 to the upper
end portion of the cylindrical main body 2, specifically the upper surface of the flange (fixing
portion 23) of the outer covering portion 21; The vibrating portion 31 disposed inside the gap s1
via the gap s1, and the connecting portion 32 which connects the vibrating portion 31 so as to
be movable relative to the frame 30 in the axial direction (axial direction of the cylindrical main
body 2) And consists of. The height of the upper surface of the fixing portion 23 to which the
frame portion 30 is fixed is set to be the same as or higher than the upper end surface 22 of the
inner cylindrical portion 20. Therefore, the diaphragm 3 is substantially flat. Preferably, the
vibrating portion 31 is provided so as to cover the opening 2 a of the cylindrical main body 2.
[0022]
The shape of the outer peripheral edge facing the gap s1 of the vibrating portion 31 with the
frame portion 30 is a true circular shape substantially along the opening edge of the inner
cylindrical portion 20, but is not limited thereto. The diaphragm 3 is made of a nonmagnetic
material, for example, stainless steel of SUS304. Therefore, although the diaphragm 3 does not
constitute a magnetic circuit, the magnet 5 fixed to the lower surface of the diaphragm 3 is
surrounded by the peripheral wall 24 of the inner cylindrical portion 20 of the magnetic body. It
03-05-2019
7
is efficiently captured at the top of the
[0023]
Of course, the diaphragm 3 may be made of a magnetic material such as SUS430 in the same
manner as the inner cylindrical portion 20. In this case, since the diaphragm 3 constitutes a
magnetic circuit, the outer peripheral edge of the vibrating portion 31 is shaped along the
opening edge 22a (upper end edge of the peripheral wall 24) of the inner cylindrical portion 20
as in this example. With the shape, the flow of the magnetic flux is smoothly formed from the
outer peripheral edge 31 a to the opening edge 22 a of the cylindrical main body 2, and the
magnetic leakage can be further suppressed. The vibration portion 31 is provided with a
mounting hole 31b for attaching a vibration transmission member (not shown), and when used
as a bone conduction speaker, the vibration of the vibration portion 31 is transmitted to the scalp
or the like of a human body through the vibration transmission member. As a result, even a deaf
person with an abnormality in the eardrum and earlobes in the skull of the human body can
surely hear the sound if the cochlea and the auditory nerve are normal.
[0024]
The magnet 5 has a cylindrical shape in a plan view and a substantially circular shape (perfect
circle) substantially similar to the inner peripheral surface of the inner cylindrical portion 20, and
is coaxial with the inner cylindrical portion 20 in the lower surface 3 c of the diaphragm 3. While
being fixed at a position (approximately the center of the vibrating portion 31), the lower surface
side is disposed to face the upper end surface 4a of the yoke 4 via a gap. As a result, the magnet
5, the yoke 4, and the inner cylindrical portion 20 that constitute the magnetic circuit are all
coaxially arranged, and an efficient magnetic circuit in which the flow of the magnetic flux
becomes uniform is formed. As the shape of the magnet 5, in addition to such a cylindrical shape,
various shapes such as a triangular prism shape, a pentagonal prism shape, and the like can be
adopted.
[0025]
The voice coil 6 is fixed on the outer peripheral surface of the yoke 4 or on the bottom surface of
the inner cylindrical portion 20 of the cylindrical main body 2. Both end portions of the coil wire
of the voice coil 6 are drawn out through the through holes 2 d of the bottom surface of the
03-05-2019
8
cylindrical main body 2, and a sound signal or the like is input to the voice coil 6 from the
outside.
[0026]
Although the embodiments of the present invention have been described above, the present
invention is not limited to these examples, and it is needless to say that the present invention can
be practiced in various forms without departing from the scope of the present invention.
[0027]
The analysis results of the sound pressure level and the magnetic flux density distribution
calculated by computer simulation for each of the models of Example 1 and Comparative
Examples 1 to 3 will be described below.
[0028]
The model of Example 1 is the bone conduction device according to the present invention (FIGS.
1 to 3), and the model of Comparative Example 1 is the conventional bone conduction device
(FIGS. 1 and 2 described in Patent Document 1). The structure in which the vibration transfer
plate is provided), the model of Comparative Example 2 corresponds to the structure of Example
1 in which a part of the coil case is cut (FIG. 4), and the model of Comparative Example 3
corresponds to the structure of Example 1 Among them, the coil case and the resin case were
integrated (FIG. 5).
[0029]
In the model of Example 1, the diaphragm is made of SUS304 (spring steel) having an outer
diameter of 20 mm and a thickness of 0.7 mm, and the cylindrical main body (inner cylindrical
portion) has an outer diameter of 14 mm and a height of 6.1 mm. 1mm thick SUS430, cylindrical
main body (outside covering part), peripheral wall, bottom wall made of PPS 1.5mm in thickness,
yoke, outer diameter 4.5mm, height 3.4mm excluding crimped part The magnet made of SS400
was an N-35 material having an outer diameter of 7 mm and a thickness of 1 mm, and a coil was
a copper wire.
[0030]
In the model of Comparative Example 1, the permanent magnet (90) is a magnet N-35 having the
same material and dimensions as in Example 1, and the diaphragm (70) and the iron piece (60)
03-05-2019
9
are made of SUS304 as in Example 1. The yoke (20) was made of SS400 as in the first
embodiment, and the coil (40) was a copper wire as in the first embodiment.
The vibration transmission plate on the permanent magnet (90) was made of SUS430.
[0031]
In the model of Comparative Example 2, as shown in FIG. 4, the inner cylindrical portion and the
outer covering portion both have a structure in which a portion excluding the peripheral wall in
the range of 90 ° in plan view is cut out (also notched portion The pair of opposing notches in
the range of 90 ° in plan view), the other dimensions, the material, and the like are the same as
in the first embodiment.
[0032]
The model of Comparative Example 3 has a structure in which as shown in FIG. 5, the outer
covering portion is omitted, the cylindrical main body is made only to the inner cylindrical
portion, and a fixing portion for fixing the diaphragm to the inner cylindrical portion is provided.
.
Other dimensions, materials and the like were the same as in Example 1.
[0033]
Tables 1 and 2 show the analysis results of displacement amounts and sound pressure levels of
the models of the embodiment and the comparative example.
For these calculations, simulation software "JMAG" manufactured by JSOL Co., Ltd. was used.
[0034]
Specifically, the thrust of each model is calculated by the magnetic field analysis simulation
03-05-2019
10
program, and the displacement amount when this calculated thrust is applied to the diaphragm
of each model is determined by structural analysis simulation.
The sound pressure level (SPL) is obtained by converting the calculated displacement amount
into the sound pressure with the amplitude value of the following equation 1.
[0035]
[0036]
The sound pressure (P, Pref) of Equation 1 is described as an amplitude value.
In order to calculate the sound pressure level, it is converted to an effective value in parentheses.
The sound pressure P at each node is calculated using the displacement speed of the surface set
to the sound pressure condition. In this analysis, all surfaces of the model are surfaces set to the
sound pressure condition.
[0037]
[0038]
[0039]
As can be seen from Tables 1 and 2, the sound pressure level is increased at all frequencies in
the model of Example 1 as compared with Comparative Example 1 which is a conventional bone
conduction driver.
In contrast to Comparative Example 1 in which the magnet is provided on the upper side of the
diaphragm and the peripheral wall is not provided all around, in Example 1 according to the
03-05-2019
11
present invention, the magnetic flux of the magnet provided on the lower surface of the
diaphragm is The sound pressure level is considered to be increased at all frequencies because
the cylindrical main body peripheral wall surrounding the circumference is efficiently captured
and an efficient magnetic circuit having a uniform magnetic flux is formed.
[0040]
In addition, in comparison with Comparative Example 2 which differs only in the model of
Example 1 and the point having a notch in the peripheral wall, the sound pressure level is
increased at all frequencies although there is no difference as compared with Comparative
Example 1 As described above, the effect of providing the circumferential wall of the cylindrical
main body over the entire circumference has been demonstrated.
[0041]
Also, in comparison with Comparative Example 3 which differs only in the model of Example 1
and the peripheral wall made up of only the inner cylindrical portion, the sound pressure level is
increased in the frequency band of 4000 Hz or less. If the inner tubular part has a simple
structure that does not have a fixed part with a complicated shape, the flow of magnetic flux
becomes uniform, and frequencies up to about 4000 Hz that are usually used (for example,
human voice is 300 to 700 Hz) It can be seen that efficiency and output can be further pursued
in
[0042]
The analysis results of the magnetic flux density distribution of each model of the example and
the comparative example are as shown in FIG.
The magnetic flux density distribution was calculated using simulation software “JMAG”
manufactured by JSOL Corporation.
[0043]
Comparing the magnetic flux density distribution of Example 1 of FIG. 6 with the magnetic flux
density distribution of Comparative Example 1 of FIG. 7, in Comparative Example 1, the magnetic
flux is concentrated on the upper portion of the magnet and the side wall of the case besides the
central yoke portion. Leakage of magnetic flux and saturation of magnetic flux on the side wall of
the case, so that the sound pressure level does not extend as described above.
03-05-2019
12
[0044]
Similarly, comparing the magnetic flux density distribution of Example 1 (FIG. 6) and the
magnetic flux density distribution of Comparative Example 2 of FIG. 8, in Comparative Example
2, the remaining portion of the notched peripheral wall constitutes a magnetic circuit. It can be
seen that the magnetic flux is concentrated and saturation occurs, and the flow of the magnetic
flux becomes uneven, leading to the result that the sound pressure level falls as compared with
the first embodiment as described above.
[0045]
Similarly, when the magnetic flux density distribution of Example 1 (FIG. 6) and the magnetic flux
density distribution of Comparative Example 2 of FIG. 9 are compared, in Comparative Example
2, the magnetism is dispersed in the portion of the flange which is the fixed portion of the inner
cylindrical portion. It can be seen that the flow of the magnetic flux becomes uneven to induce
the magnetic leakage, and the magnetic flux is concentrated in the place from the fixing portion
to the lower part of the peripheral wall, and the sound pressure level is thus lowered.
[0046]
DESCRIPTION OF SYMBOLS 1 bone conduction device 2 cylindrical main body 2a opening part
2b inner bottom surface 2c surrounding wall 2d through hole 3 diaphragm 3c lower surface 4
yoke 4a upper end surface 5 magnet 5b lower end surface 6 voice coil 7 attachment screw 20
inner cylindrical portion 20c attachment hole 21 outside Cover part 22 upper end face 22a
opening edge part 23 fixed part 24 peripheral wall 25 bottom wall 26 peripheral wall 30 frame
part 31 vibrating part 31a outer peripheral edge 31b mounting hole 32 connecting part s1 gap
03-05-2019
13
Документ
Категория
Без категории
Просмотров
0
Размер файла
24 Кб
Теги
jp2015186102
1/--страниц
Пожаловаться на содержимое документа