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JP2012175240

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This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
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DESCRIPTION JP2012175240
The present invention provides an electrodynamic exciter capable of bringing the sound quality
of the generated sound closer to a desired one even when the vibration characteristics of the
vibration target to which the electrodynamic exciter is attached are different. A magnetic circuit
portion having an outer yoke, a magnet, and an inner yoke, in which a magnetic gap is formed, a
voice coil disposed in the magnetic gap, and a diaphragm to which the voice coil is fixed. An
electrodynamic exciter provided with an elastic body that elastically connects a magnetic circuit
portion and a diaphragm is provided with means for changing the vibrational motion of the
elastic body. [Selected figure] Figure 1
Electrodynamic exciter
[0001]
The present invention is applied to a thin panel speaker utilized to achieve thinning of various
electronic devices such as a television and a personal computer, and an electrodynamic type
applied to an electric moving body to be applied to notification sound generation. It relates to the
structure of the exciter.
[0002]
2. Description of the Related Art An electrodynamic exciter has often been adopted for thin panel
speakers mounted on home appliances such as thin liquid crystal TVs, thin plasma TVs, thin
personal computers, and various monitor devices of industrial machine tools.
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That is, the conventional dynamic exciter comprises a bowl-shaped inner yoke, a permanent
magnet, an outer yoke, a voice coil, a diaphragm, and an adhesive member, and a voice coil is
formed in the gap between the inner yoke and the outer yoke side wall. The diaphragm is
disposed integrally with the voice coil. The voice coil vibrates in the axial direction by passing a
current consisting of a predetermined signal to the voice coil in the magnetic circuit composed of
the permanent magnet, the inner yoke and the outer yoke, and the voice coil is integrally fixed.
Sound waves are emitted by exciting the diaphragm.
[0003]
For example, the electrodynamic exciter according to Patent Document 1 is integrated with a
voice coil by an elastic holding body having appropriate elasticity such as urethane foam on an
axial end face of a magnetic circuit consisting of an inner yoke, a magnet and an outer yoke. It
has a structure in which a vibrating member composed of a fixed diaphragm is attached.
[0004]
In addition, the dynamic exciter according to Patent Document 2 includes a magnetic circuit
formed of a bowl-shaped outer yoke, a plate-like magnet and an inner yoke sequentially stacked
inside the outer yoke, and an outer of the magnetic circuit. A voice coil disposed in an air gap
formed between an inner peripheral portion of a side wall of the yoke and an outer peripheral
portion of the inner yoke, and a sub-panel corresponding to a diaphragm holding the voice coil in
front of the magnetic circuit; It has a structure in which the vicinity of the center of gravity in the
thickness direction of the magnetic circuit and the sub-panel are held by a plurality of arc-shaped
strip-like thin elastic supports.
[0005]
In Patent Document 3, one end prepares a first suspension fixed to the outer yoke and the other
end fixes the first suspension fixed to the fixing member, and one end prepares a second
suspension fixed to the voice coil and the other end fixed to the fixing member. And try to
improve the frequency response.
Further, the suspension is exemplified by metal, resin, elastic member, sponge, rubber, etc., and a
spring coefficient for determining the frequency characteristic is predetermined.
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[0006]
JP-A-10-243491 JP-A-2003-143690 JP-A-2005-354297
[0007]
In a conventional electrodynamic exciter, a magnetic circuit portion composed of an outer yoke,
an inner yoke, and a magnet and a fixed portion including a voice coil are supported by an elastic
support, and the material of the elastic support has a spring coefficient This elasticity determines
the vibrational motion, so that the frequency range of the sound is fixed by the material of the
elastic support.
[0008]
On the other hand, recently, it has been proposed to emit a notification sound in order to notify
the presence of a motor-driven movable body excellent in quietness driven by an electric motor,
such as an electric car or a hybrid car.
With regard to the generation of the notification sound, it is conceivable to attach the
electrodynamic exciter, for example, to the body of the motor-driven movable body and generate
the alarm sound from the body of the motor-driven movable body.
At this time, the vibration characteristic of the body of the motor-driven movable body has
various characteristics depending on each motor-driven movable body or the position of the
body.
On the other hand, since the vibration characteristics of the electrodynamic exciter are fixed,
there is a problem that the frequency characteristics of the generated notification sound are
influenced by the vibration characteristics of the body of the motorized moving body.
[0009]
The present invention has been made to solve the problems of the conventional electrodynamic
exciter as described above, and can change the vibration characteristic of the electrodynamic
exciter, and the vibrator to which the electrodynamic exciter is attached is provided. An object of
the present invention is to provide an electrodynamic exciter capable of bringing the sound
quality of the generated sound closer to a desired one even if the vibration characteristics are
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different.
[0010]
According to the present invention, there is provided a magnetic circuit portion having an outer
yoke, a magnet and an inner yoke, in which a magnetic gap is formed, a voice coil disposed in the
magnetic gap, and a diaphragm on which the voice coil is fixed. An electrodynamic exciter
provided with an elastic body that elastically connects a magnetic circuit portion and a
diaphragm, is provided with means for changing the vibrational motion of the elastic body.
[0011]
According to the present invention, the frequency characteristics of the vibration of the
electrodynamic exciter can be made variable by changing the energy stored in the elastic body,
so that the vibration characteristics of the vibrator to which the electrodynamic exciter is
attached are different. Even in this case, the frequency characteristics of the generated sound can
be made closer to a desired one.
[0012]
FIG. 1 is a half cross-sectional view showing a configuration of an electrodynamic exciter
according to a first embodiment of the present invention.
It is an expanded sectional view showing the principal part of the composition of the dynamoelectricity exciter by Embodiment 1 of this invention.
It is a top view which shows schematic structure of the electrodynamic exciter by Embodiment 1
of this invention.
It is an expanded sectional view showing the principal part of the general electrodynamic exciter
composition used in order to explain the operation of the electrodynamic exciter by Embodiment
1 of this invention. FIG. 7 is an enlarged sectional view of a stationary state for explaining the
operation of the electrodynamic exciter according to the first embodiment of the present
invention. It is an expanded sectional view of the dynamic state for demonstrating operation |
movement of the electrodynamic exciter by Embodiment 1 of this invention. It is an expanded
sectional view of another dynamic state for demonstrating operation | movement of the
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electrodynamic exciter by Embodiment 1 of this invention. It is an expanded sectional view which
shows the principal part of a structure of the electrodynamic exciter by Embodiment 2 of this
invention. It is an expanded sectional view which shows the principal part of a structure of the
electrodynamic exciter by Embodiment 3 of this invention. It is an expanded sectional view which
shows the principal part of a structure of the electrodynamic exciter by Embodiment 4 of this
invention. It is an expanded sectional view which shows the principal part of another structure of
the electrodynamic exciter by Embodiment 4 of this invention.
[0013]
Embodiment 1 FIG. 1 is a half sectional view showing a configuration of an electrodynamic
exciter according to a first embodiment of the present invention, a half sectional view, FIG. 2 is an
enlarged sectional view of a main part, and FIG. 3 is a plan view. The half sectional view of FIG. 1
is a view taken along the line AA in FIG. 3, that is, the left half. In FIG. 1 to FIG. 3, 1 is an inner
yoke made of a magnetic material, 2 is a magnet made of a rare earth or the like, and 3 is an
outer yoke made of a magnetic material in a bowl shape. One axial end face of the magnet 2 is in
contact with the inner bottom surface of the outer yoke 3 in the axial direction, and the other
axial end face of the magnet 2 is in contact with the inner yoke 1 made of a magnetic material.
The outer yoke 3 and the magnet 2 and the magnet 2 and the inner yoke 1 are respectively
joined by an adhesive (not shown). In addition, a gap (gap) is provided between the radially outer
peripheral surface of the inner yoke 1 and the inner peripheral wall surface of the bowl-shaped
edge portion of the outer yoke 3, and the magnet 2, the inner yoke 1 and the outer yoke 3 form
the magnetic circuit portion 100. Configured.
[0014]
A voice coil 4 is wound around a bobbin 40, and a thin flat diaphragm 5 is disposed so that the
voice coil 4 is positioned in a gap portion (gap) of the magnetic circuit unit 100, and the voice
coil 4 is wound. The rotated bobbin 40 is integrally held by the diaphragm 5. The outer yoke 3
has a collar 31 projecting radially in the axial center portion outer wall surface, and the
diaphragm 5 has a collar 51 facing the edge 31 of the outer yoke 3 at the radial end. doing. By
attaching the diaphragm 5 in contact with the body 6 to be vibrated, the vibration of the
diaphragm 5 is transmitted to the body 6 to generate a sound.
[0015]
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Here, the fastening portion 13 for fastening the outer yoke 3 and the diaphragm 5 includes the
support bolt 9 penetrating the flange portion 31 of the outer yoke 3 and the flange portion 51 of
the diaphragm 5 and the first elastic body structure portion 121 , And the second elastic body
structure portion 122. The first elastic body structure portion 121 includes the elastic body
pressing plates 111 and 112 sandwiching the first elastic body 7 located between the collar
portion 31 of the outer yoke 3 and the head of the support bolt 9, and the first elastic body
structure portion 121. The elastic body 7 is constituted by a screw 91 which applies a force in
the direction of contraction. The second elastic body structure portion 122 includes elastic body
pressing plates 113 and 114 sandwiching the second elastic body 8 located between the flange
portion 31 of the outer yoke 3 and the flange portion 51 of the diaphragm 5, and It consists of a
screw 92 which applies a force to the second elastic body 8 in the direction of contraction.
Further, one end of the support bolt 9 is coupled by a nut 102 so as not to drop off the first
elastic body structure portion 121, the second elastic body structure portion 122, the outer yoke
3, and the diaphragm 5. The support bolts 9 pass through the elastic body pressing plates 111,
112, 113, and 114. The fastening portion 13 having such a configuration fixes the movement of
the outer yoke 3 and the vibrating plate 5 in one direction. The first elastic body 7 and the
second elastic body 8 can be formed of an annular member having a through hole in the center
through which the support bolt 9 can penetrate, by an elastic material such as rubber. For
example, as shown in FIG. 3, the fastening portion 13 is provided at a plurality of three or more
places to connect the outer yoke 3 and the diaphragm 5.
[0016]
Furthermore, an O-ring 12 for sealing between the outer yoke 3 and the diaphragm 5 is provided
around the outer yoke 3, and water or dust from the outside enters the inside surrounded by the
outer yoke 3 and the diaphragm 5. Is supposed to prevent.
[0017]
Next, the operation will be described.
First, consider a configuration as shown in FIG. 4 as a simple configuration. The outer yoke 3
constituting the magnetic circuit unit 100 and the diaphragm 5 excited by energization of the
voice coil 4 are elastically supported by the first elastic body 70 and the second elastic body 80.
The first elastic body 70 and the second elastic body 80 are simultaneously tightened by screws
95. In this state, when the electrodynamic exciter is driven, the diaphragm 5 is displaced relative
to the outer yoke 3, so the gap 35 is increased or decreased by the dynamic amplitude change of
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the outer yoke 3 and the diaphragm 5. . At this time, since the diaphragm 5 and the outer yoke 3
are coupled via the two elastic bodies of the first elastic body 70 and the second elastic body 80,
the electrodynamic exciter has a spring coefficient of the elastic body. Have a resonant frequency
corresponding to
[0018]
The equation of motion when an object having a mass M is connected to an elastic portion
(elastic support portion composed of a spring, rubber, etc.) having a spring coefficient k is
expressed as Therefore, the displacement amount x of the distance is expressed as follows using
the maximum amplitude A and the initial phase φ, and is expressed as vibration displacement.
This vibration affects the displacement of vibration due to the voice coil 4 and the magnetic
circuit 100, and thus affects the characteristics of the sound, that is, the sound quality.
[0019]
In the case of an electrodynamic exciter as shown in FIG. 4, the object having a mass is a
magnetic circuit portion, and the two elastic members of the first elastic member 70 and the
second elastic member 80 are elastic portions, and the resonance frequency is Determine the
frequency range of the sound when using an electrodynamic exciter. In other words, the filter
whose bottom part is near the resonance frequency is configured. The equation of motion when
the magnetic circuit unit is connected to the first elastic body 70 having a spring coefficient k1
and the second elastic body 80 having a spring coefficient k2 is expressed as follows. Therefore,
the displacement amount x of the distance is expressed as, and is expressed as vibration
displacement. This vibration affects the displacement of vibration due to the voice coil 4 and the
magnetic circuit 100, and thus affects the sound quality.
[0020]
Next, the operation of the dynamic exciter according to the first embodiment of the present
invention will be described with reference to FIGS. 5 to 7 are the same as FIG. 2, but the first
elastic body 7 and the second elastic body 8 are equivalently shown by springs. Also, in practice,
the elastic body 7 and the elastic body 8 may be springs instead of elastic bodies such as rubber.
FIG. 5 shows a state in which the force F1 is applied by the screw 91 to the elastic body 7 of the
spring coefficient k1, and the force F2 is applied by the screw 92 to the elastic body 8 of the
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spring coefficient k2. There is. Further, the maximum distance x1 of the elastic body 7 is limited
by the screw 91, and the maximum distance x2 of the elastic body 8 is limited by the screw 92.
In this state, as shown in FIG. 6, when the outer yoke 3 is displaced and moved by a distance x in
the direction in which the elastic body 8 is contracted, the elastic body 7 is limited in distance by
the screw 91, thus contributing to the outer yoke Is eliminated, and the equation of motion is
expressed as Thus, since the influence of the elastic body 7 is eliminated and the influence of the
force F2 by the screw 92 is added, the maximum amplitude and phase are affected compared to
the case where the force F2 is not applied, and the following equation Become. It is expressed as
[0021]
Further, as shown in FIG. 7, when the outer yoke 3 is displaced and moved by a distance x in the
direction in which the elastic body 7 is contracted, the distance to the outer yoke is limited by the
screw 92 and the motion equation is It is expressed as Thus, since the influence of the elastic
body 8 is eliminated and the influence of the force F1 by the screw 91 is added, the maximum
amplitude and the phase are affected as compared with the case where the force F1 is not
applied, and the following equation Become. It is expressed as
[0022]
As mentioned above, it is expressed as vibration displacement of movement by structure. Since
the vibration displacement by this structure affects the vibration displacement by the voice coil 4
and the magnetic circuit 100, it affects the characteristics of the sound, so that the sound quality
can be adjusted by the screws 91 and 92.
[0023]
For example, when the dynamic exciter according to the first embodiment is attached to the back
side of the motorized moving body as a sound generator for generating a notification sound of
the motorized moving body, and the board of the bonnet is By adjusting the screws 91 and 92 of
the electric exciter, the tone quality of the notification sound is adjusted. In another type of
motorized moving body, when the same design electrodynamic exciter is attached to the back of
the motorized body bonnet and the board of the bonnet is made the plate 6 to be vibrated, the
vibration characteristics of the bonnet are different. The sound to be generated is a notification
sound of a different sound quality, but can be adjusted to a sound quality close to a desired
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sound quality by the screws 91 and 92 of the electrodynamic exciter. As described above, even if
the electrodynamic exciter of the same design is attached to various types of diaphragms, it is
possible to generate a sound having a sound quality close to a desired sound quality as the
notification sound only by adjusting the screws 91 and 92.
[0024]
Second Embodiment FIG. 8 is an enlarged cross-sectional view of the main part showing the
configuration of a dynamic exciter according to a second embodiment of the present invention. In
FIG. 8, the same reference numerals as in FIGS. 1 to 3 denote the same or corresponding parts. In
the second embodiment, as shown in FIG. 8, the first elastic body structure portion 121 includes
the elastic body 7 and the damper 141, and the second elastic body structure portion 122
includes the elastic body 8 and the damper 142. .
[0025]
Using the viscosity coefficient D1 of the damper 141 and the viscosity coefficient D2 of the
damper 142, the equation of motion when the damper as shown in FIG. 8 is configured is
expressed as follows. If the displacement x is expressed as D = D1-D2 and k = k1-k2, it is
represented as follows. However, λ1 and λ2 are respectively
[0026]
Thus, it is expressed as vibrational displacement of movement by structure. The vibration
displacement by the electrodynamic exciter of the structure shown in FIG. 8 affects the vibration
displacement by the voice coil 4 and the magnetic circuit 100, which affects the frequency of the
sound. By adjusting, the sound quality can be adjusted.
[0027]
Third Embodiment FIG. 9 is an enlarged cross-sectional view of the main part showing the
configuration of the dynamic exciter according to the third embodiment of the present invention.
In FIG. 9, the same reference numerals as in FIGS. 1 to 3 denote the same or corresponding parts.
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In the third embodiment, as shown in FIG. 9, an O-ring 128 for sealing between the outer yoke 3
and the diaphragm 5 comprises a ridge 31 of the outer yoke 3 and a diaphragm 31 facing the
ridge 31 of the outer yoke. It is provided between the weir 51 and the weir. Here, the O-ring 128
is formed of an elastic material such as rubber.
[0028]
In the electrodynamic exciter according to the third embodiment of the present invention
configured as described above, the outer yoke 3 constituting the magnetic circuit and the
diaphragm 5 excited by energization to the voice coil 4 are elastic materials. It is elastically
supported by the O-ring 128 and the first elastic body 7 formed by
[0029]
By tightening the screw 91, the first elastic body 7 is contracted.
The O-ring 128 seals the outer yoke 3 and the diaphragm 5 to prevent the entry of water into the
magnetic circuit 100 and therefore does not have a variable structure. For this reason, a motion
equation involving only the spring coefficient k2 of the O ring 128 in the direction in which the
O ring 128 is contracted, the spring coefficient k2 of the O ring 128 in the direction in which the
first elastic body 7 is contracted It becomes an equation of motion by the spring coefficient k1 of
the elastic body 7 and the force F1 by the screw 91. In this manner, the electrodynamic exciter
according to the third embodiment can also adjust the sound characteristics by adjusting the
screw 91 as in the first embodiment. For example, if the electrodynamic exciter according to the
third embodiment is used for the generator of notification sound of the motor-driven movable
body, adjustment of the screw 91 can be performed even when the electrodynamic exciter is
attached to different motorized mobile bodies or different positions. It is possible to generate a
notification sound with a sound quality close to the desired sound quality. In addition, since the
O-ring 128 doubles as an elastic support, the number of parts can be reduced compared to the
dynamic exciter of the first embodiment.
[0030]
Fourth Embodiment FIG. 10 is an enlarged cross-sectional view of the main part showing the
configuration of the electrodynamic exciter according to the fourth embodiment of the present
invention. In FIG. 10, the same reference numerals as in FIGS. 1 to 3 denote the same or
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corresponding parts. As shown in FIG. 10, the variable mechanism of the first elastic body
structure portion 121 in the first embodiment is omitted, and only the variable mechanism by the
second elastic body structure portion 122 is included.
[0031]
FIG. 11 is an enlarged cross-sectional view of the main part, showing the configuration of another
electrodynamic exciter according to a fourth embodiment of the present invention. In FIG. 11, the
same reference numerals as in FIGS. 1 to 3 denote the same or corresponding parts. As shown in
FIG. 11, the variable mechanism of the second elastic body structure portion 122 in the first
embodiment is omitted, and only the variable mechanism by the first elastic body structure
portion 121 is included.
[0032]
In the electrodynamic exciter according to the third embodiment of the present invention
configured as described above, the outer yoke 3 constituting the magnetic circuit 100 and the
diaphragm 5 excited by energization to the voice coil 4 are springs. It is elastically supported by
the first elastic body 71 and the second elastic body 81 formed by
[0033]
Therefore, when it is contracted in the direction not having the variable mechanism, it is an
equation of motion involving only the spring coefficient kx (k1 in FIG. 10, k2 in FIG. 11) of the
elastic body without the variable mechanism. When contracted, the force by the spring
coefficient kx of the elastic body without variable mechanism and the spring coefficient ky with
variable mechanism (k2 in FIG. 10, k1 in FIG. 11) and screw (screw 92 in FIG. 10, screw 91 in
FIG. 11) It becomes an equation of motion by F.
In this manner, the electrodynamic exciter according to the fourth embodiment can also adjust
the sound characteristics by adjusting the screws 91 or 92 as in the first embodiment. For
example, according to the electrodynamic exciter according to the fourth embodiment of the
present invention, the adjustment of the screw 91 or 92 is performed even when the
electrodynamic exciter is attached to a different motorized mobile body or a different position.
Thus, it is possible to generate a notification sound with a sound quality close to the desired
sound quality.
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[0034]
1: inner yoke 2: magnet 3: outer yoke 4: voice coil 5: diaphragm 6: vibration receiving body 7,
71: first elastic body 8, 81: second elastic body 9, 91, 92: screw 12 , 128: O-ring 13: Fastening
part 31: 鍔 of inner yoke 51: 鍔 of diaphragm 100: magnetic circuit part 121: first elastic body
structure part 122: second elastic body structure part 141, 142: damper
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