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JP2006302937

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This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
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DESCRIPTION JP2006302937
The present invention provides a magnetostrictive element actuator which can be incorporated
into a narrow device or a small-sized device such as a display device of a portable device, and can
drive a relatively high rigidity driven member. A magnetostrictive element actuator drives a
driven member by magnetostrictive deformation in a material length direction of a giant
magnetostrictive element. The giant magnetostrictive element has a flat and thin form in which
the material length is set to a dimension equal to or less than the cube root of the volume. The
through hole 4 in the axial direction is formed in the axial core portion of the giant
magnetostrictive element, and the bias magnetic field permanent magnet 21 is accommodated in
the hollow portion formed by the through hole, and the field outside the giant magnetostrictive
element A coil 22 is disposed. [Selected figure] Figure 3
Magnetostrictive element actuator
[0001]
The present invention relates to a magnetostrictive element actuator, and more particularly to a
magnetostrictive element actuator for driving a driven member by magnetostrictive deformation
in the material length direction of the giant magnetostrictive element.
[0002]
In recent years, small portable devices such as mobile phones, PDAs and portable terminals have
been widely spread, but with the development of communication means and information transfer
means, various functions such as video transmission, TV reception, games etc. are required to
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portable devices There is a tendency to
In order to make portable devices multifunctional, there is a need to further improve or enhance
the AV expression capability of the portable devices. Also, with the spread of such portable
devices, high-quality portable audio reproducing devices are also becoming particularly popular
in recent years. Such recent trends suggest a new direction of portable devices, which predicts
the spread and development of further portable devices in consideration of the birth movement
of narrow casting and the like.
[0003]
On the other hand, this type of portable device is essentially required to be thin, small and power
saving. The conditions of such portable devices are incompatible with the functions as AV
devices, for example, the functions of TV reproduction, moving image reproduction, etc., and are
obstacles to making portable devices multifunctional or high performance. .
[0004]
For example, the enlargement of the screen of the portable device results in limiting or restricting
the installation space of the audio device such as a speaker, and it is actually to make the display
function of the screen and the audio function of the audio device compatible. It is extremely
difficult. For example, many mobile phones currently in the market adopt a configuration in
which the speaker opening is disposed on the back of the display unit, but such arrangement of
the speaker opening may cause discomfort to the user. There is.
[0005]
Also, when the mobile phone has an AV function, the user usually views in a state where the head
is separated from the display unit by several tens of centimeters. Although it may be assumed
that the receiver of the mobile phone is used as an audio device for moving image reproduction,
the receiver of the mobile phone is based on the premise that the user brings the ear close to the
receiver, so high sound Does not have an output. On the other hand, a method is conceivable in
which acoustic energy is output by dividing and vibrating the screen front plate of the mobile
phone by the piezoelectric element, but to view with the head separated from the display unit,
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the normal telephone function Sound energy of the sound pressure level of several tens dB high
must be output on the screen front plate. However, in the configuration in which a piezoelectric
element is used as an acoustic drive source, the ability to output acoustic energy at such a high
sound pressure level can not be obtained.
[0006]
Magnetostrictive elements that expand and contract in response to changes in the input magnetic
field are known. In recent years, magnetostrictive materials have been discovered that exhibit
magnetostrictive deformation whose displacement amount exceeds about 1000 ppm of the
magnetostrictive element length, and research is conducted to use such giant magnetostrictive
elements as components of various actuators such as speaker drive sources. ing.
[0007]
For example, the magnetostrictive actuator disclosed in Japanese Patent Application Laid-Open
No. 2000-315829 has a planar magnetostrictive element magnetostrictively deformed in a
direction perpendicular to the direction of the magnetic field, and the magnetostrictive element
comprises an excitation coil wound around its outer peripheral region. The magnetic field
deforms in an out-of-plane direction (direction orthogonal to the surface). The speaker driver
disclosed in Japanese Patent Application Laid-Open No. 2000-341791 uses a thin plate-like
magnetostrictive element which magnetostrictively deforms in a direction perpendicular to the
direction of the magnetic field as a drive source of the speaker diaphragm, and responds to the
input magnetic field. The speaker diaphragm is configured to be vibrated by the out-of-plane
deformation of the element. As described above, a speaker driving source utilizing displacement
of the planar magnetostrictive element in the out-of-plane direction is disclosed in the same
manner in Japanese Patent Application Laid-Open Nos. 2000-341792, 2000-341793, and 2000341794. There is.
[0008]
Further, a speaker drive source utilizing expansion and contraction of the magnetostrictive
element in the magnetic field direction or a vibrator drive source for a mobile phone is disclosed
in Japanese Patent Application Laid-Open Nos. 2004-363967, 2004-26307, and 2004-289443.
It is disclosed. In these devices, in order to effectively use the axial displacement of a minute
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magnetostrictive element, the magnetostrictive element is formed on an elongated shaft member,
whereby a relatively large absolute stretch in the axial direction due to a displacement of about
1000 ppm of the magnetostrictive element length. I'm getting the amount. JP, 2000-315829, JP,
2000-341791, JP, 2000-341792, JP, 2000-341, 793, JP, 2000-341, 794, JP, 2004-363, 967,
JP, 2004-26, 307, A Special feature Open 2004-289443 gazette
[0009]
However, a speaker drive source of the type utilizing displacement of the planar magnetostrictive
element in the out-of-plane direction and a speaker drive source of the type ensuring the
absolute expansion amount depending on the axial length of the axial magnetostrictive element
are thin and small. It can not be incorporated into a portable device designed with an emphasis
on external shape.
[0010]
In addition, the surface of the display unit of the portable device is protected by a relatively high
rigidity transparent plate, and the axial direction generating force of the magnetostrictive
element formed as an elongated shaft member drives such a transparent plate, It can not be
vibrated.
[0011]
The present invention has been made in view of such circumstances, and the object of the
present invention is to be incorporated in narrow-sized or small-sized devices such as display
devices of portable devices and the like, and relatively. An object of the present invention is to
provide a magnetostrictive element actuator capable of driving a highly rigid driven member.
[0012]
The present invention, in order to achieve the above object, in a magnetostrictive element
actuator for driving a driven member by magnetostrictive deformation in the material length
direction of the giant magnetostrictive element, a flat thin supermagnetostrictive material having
a material length set to a dimension of cubic root or less of volume. Provided is a
magnetostrictive element actuator characterized by having an element.
[0013]
According to the above configuration of the present invention, the actuator has the flat and thin
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giant magnetostrictive element.
The amount of displacement in the axial direction is relatively small in flat and thin super
magnetostrictive elements.
On the other hand, the generated force in the axial direction of the giant magnetostrictive
element is high, and a highly rigid driven member can be driven.
In addition, the flat-thinned super magnetostrictive element can be inserted into a space of a
small size formed between the support member of the super magnetostrictive element and the
driven member.
[0014]
In addition, the flat and thin super-magnetostrictive element has a large cross-sectional
coefficient, and hence the bending stress acting on the super-magnetostrictive element is
reduced.
Therefore, the resistance of the giant magnetostrictive element to external force acting on the
giant magnetostrictive element, in particular, bending moment is improved. Therefore, flat and
thin super-magnetostrictive element is advantageous in preventing destruction of the supermagnetostrictive element.
[0015]
Furthermore, in the actuator provided with the flat-thinned super-magnetostrictive element, the
ratio of the element occupying the magnetic path and the air is relatively reduced as compared
with the elongated magneto-strictive element. This makes it possible to reduce the
magnetomotive force of the field coil for producing the magnetic field strength necessary for
driving, and contributes to the power saving of the actuator using the giant magnetostrictive
element.
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[0016]
In the magnetostrictive element actuator according to the present invention, the through hole in
the axial direction is formed in the axial core portion of the super magnetostrictive element, and
the permanent magnet for bias magnetic field is accommodated in the hollow portion formed by
the through hole. According to another aspect of the present invention, there is provided a
magnetostrictive element actuator characterized in that a field coil is disposed outside the giant
magnetostrictive element.
[0017]
According to the configuration of the present invention in which the permanent magnet is
disposed in the hollow portion and the field coil is disposed outside the super magnetostrictive
element, the field coil lead can be easily attached to and detached from the field coil.
The arrangement of such permanent magnet and field coil device is advantageous in simplifying
the manufacturing process of the actuator or in improving the productivity of the actuator.
[0018]
Further, according to the configuration in which the permanent magnet is disposed in the hollow
portion, the actuator can be configured such that substantially the entire load acts on the giant
magnetostrictive element. Moreover, since it is not necessary to arrange a permanent magnet at
the shaft end of the giant magnetostrictive element, the actuator can be designed to be flat and
thin.
[0019]
Furthermore, by forming the shaft core portion in a hollow, the outer diameter of the giant
magnetostrictive element is expanded, so the section coefficient of the giant magnetostrictive
element is increased. Therefore, the resistance of the giant magnetostrictive element to bending
moment is further improved.
[0020]
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Still further, according to the present invention, in the magnetostrictive element actuator of the
above configuration, a flat magnetic yoke and prestressing means are provided, and the yokes
are arranged in pairs on the axial end face of the giant magnetostrictive element, The stressing
means consists of an elastically deformable spring clip which locks onto the outer edge of the
yoke, which gives the yokes a preload approaching each other, the axial compressive force
exerted by the yoke being as a prestress. There is provided a magnetostrictive element actuator
characterized by acting on the magnetostrictive element.
[0021]
According to the above configuration of the present invention, the actuator has a structure in
which the prestressing means is locked to the outer edge portion of the flat plate type yoke, and
the giant magnetostrictive element interposed between the yokes is held by the yoke.
The pre-stressing means does not increase the axial length of the actuator, and does not become
a factor that hinders the reduction in thickness of the actuator.
[0022]
In addition, the magnetic resistance of the yoke is extremely small compared to the giant
magnetostrictive element and air, and the length of the magnetic path can be considered to be
approximately equal to the length of the portion occupied by the giant magnetostrictive element
and air in the magnetic path. Therefore, according to the actuator of the above configuration, the
magnetic flux generated by the field coil and the permanent magnet acts on the giant
magnetostrictive element effectively and uniformly.
[0023]
Furthermore, the actuator constitutes an actuator unit provided with means for prestressing the
giant magnetostrictive element. Such an actuator unit can be manufactured as an independent
actuator unit independent of the structures of the support member and the driven member.
[0024]
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Preferably, the actuator is connected or joined to a surface layer plate constituting a display
device of the portable device to divide and vibrate the surface layer plate. For example, the
actuator is inserted between the surface layer panel and the LCD panel in the screen margin of
the display unit of the mobile phone to divide and vibrate the surface layer panel. The surface
layer plate of the display device has a relatively high rigidity, but as described above, the
magnetostrictive element made flat and thin generates a relatively large axial driving force to
drive the surface layer plate. The surface panel functions as an acoustic diaphragm, and the
vibration of the acoustic diaphragm converts it into acoustic energy. The compression wave
generated in front of the screen reaches the user as a sound wave of relatively high acoustic
energy.
[0025]
Preferably, the actuator is integrally connected or joined to the back surface of the surface plate
by an adhesive or the like. The surface layer plate or a part of the surface layer plate may be used
as a component of the actuator, for example, the giant magnetostrictive element may be directly
connected to the surface layer plate, or a portion of the surface layer plate may be used as the
yoke.
[0026]
According to the present invention, there is provided a magnetostrictive element actuator which
can be incorporated in a narrow device or small-sized device such as a display device of a
portable device, and can drive a driven member having a relatively high rigidity. be able to.
[0027]
Hereinafter, preferred embodiments of the present invention will be described in detail with
reference to the accompanying drawings.
[0028]
FIG. 1 is a diagram showing the characteristics of generated strain and generated stress of the
giant magnetostrictive element.
[0029]
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In the state where the displacement σ is completely restrained (generated strain δ = 0), the
giant magnetostrictive element generates a stress σmax of 20 MPa by the action of a magnetic
field having an intensity of 80 kA / m.
On the other hand, the giant magnetostrictive element generates a strain δmax of 1000 ppm by
the action of a magnetic field with an intensity of 80 kA / m in an unloaded state (generated
stress = 0) in which the constraint is completely released.
The generated strain δ is a value obtained by dividing the displacement amount ΔL by the
element length L of the giant magnetostrictive device, and the generated stress σ is a value
obtained by dividing the generated force F by the cross sectional area A of the giant
magnetostrictive device.
[0030]
Assuming that the generated stress σ and the generated strain δ are in inverse proportion to
each other under the action of the same magnetic field, the generated strain δ and the generated
stress σ of the giant magnetostrictive element are represented by a load characteristic line
(indicated by a broken line) and a strain / stress characteristic line. The value of the generated
strain δ1 and the generated stress σ1 at the intersection of
[0031]
Since the strain δ of the giant magnetostrictive element is about 1000 ppm (0.1%) and very
small, conventionally, an element sufficient to obtain a displacement amount ΔL that can be
effectively used for driving the driven member In order to secure the length L, it has been
considered that it is necessary to form the giant magnetostrictive element into an elongated shaft
member.
For example, a conventional actuator using a giant magnetostrictive element is designed to have
a material length (axial length) of 10 cm to 20 cm, whereby a conventional speaker that vibrates
a film member by piston movement or reciprocating movement of a drive member The amount
of displacement similar to that of the drive unit was obtained by the axial strain of the giant
magnetostrictive element.
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[0032]
From the same viewpoint, conventionally, the giant magnetostrictive element has been operated
under the condition of exceeding 70% of the maximum strain δmax (eg, δmax = 1000 ppm).
In FIG. 1, operating conditions exceeding 70% of the maximum strain δmax are shown as region
S (δ> 0.7 × δmax). However, when the giant magnetostrictive element is used under such
conditions (region S), only a relatively small generated stress σ (σ = σ2) can be obtained, and
furthermore, with the giant magnetostrictive element having the form of an elongated shaft
member A relatively small generative force F (F = σ2 × A) can only be obtained. For this reason,
the driven member (not shown) driven by the giant magnetostrictive element is limited to a
relatively low rigidity member.
[0033]
FIG. 2 is a perspective view and a longitudinal sectional view showing the giant magnetostrictive
element 1 of the present embodiment.
[0034]
The giant magnetostrictive element 1 is formed in a cylindrical form having a diameter D, a
radius R and a material length L, as shown in FIG. 2 (A).
The material length L of the giant magnetostrictive element 1 is set to a value smaller than the
cubic root of volume V = πR <2> × L, and the giant magnetostrictive element 1 has a flat and
thin form.
[0035]
As shown in FIG. 2B, the giant magnetostrictive element 1 is disposed in the space 12 between
the support member (base) 10 and the driven member 11. The flat end faces 2 and 3 of the giant
magnetostrictive element 1 are in surface contact with the support member 10 and the driven
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member 11. The support member 10 is fixed to an apparatus main body (not shown) such as a
mobile phone main body or the like, or consists of components of the apparatus main body itself.
The driven member 11 is driven by magnetostrictive deformation in the axial direction of the
giant magnetostrictive element 1.
[0036]
The driven member 11 is a member having a relatively high rigidity, for example, a transparent
and high rigidity front plate covering a display screen of a mobile phone. The magnetostrictive
deformation of the giant magnetostrictive element 1 in the material length direction is restrained
by the driven member 11, and the giant magnetostrictive element 1 is 70% or less of the
maximum strain δmax, preferably 50% or less of the maximum strain δmax. Operate. In FIG. 1,
an operating condition (δ ≦ 0.7 × δ max) of 70% or less of the maximum strain δmax is
shown as a region T.
[0037]
On the other hand, since the giant magnetostrictive element 1 has a flat and thin form in the
material length direction (the direction of load), it generates relatively high stress σ and force F
for driving the driven member 11 with relatively high rigidity. .
[0038]
That is, when forming a giant magnetostrictive element with the same material amount, if the
element length L is multiplied by 1 / n and the cross sectional area A is multiplied by n due to the
flattening of the giant magnetostrictive element, the displacement amount is 1 / n times, The
generated force F is n times.
For example, as shown in FIG. 2A, the giant magnetostrictive element formed in the form of an
elongated shaft in the load direction as in the prior art, and the giant magnetostrictive element 1
flattened in the load direction as shown in FIG. When each is molded, the displacement amount
ΔL of the flat-thinned super magnetostrictive device 1 is 1 / n times the displacement amount
ΔL of the shaft-like giant magnetostrictive device, and the generated force F of the giant
magnetostrictive device 1 is axial. It is n times the generated force F of the giant magnetostrictive
element.
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[0039]
Therefore, in the magnetostrictive element 1 having a flat and thin shape, although the
displacement amount ΔL is relatively small, the generated force F is high, and the driven
member 11 with relatively high rigidity can be driven. Moreover, as shown in FIG. 2 (B), the flatthinned super magnetostrictive element 1 can be inserted into a space 12 of a small size formed
between the driven member 11 and the support member 10.
[0040]
Moreover, according to the configuration in which the driven member 11 is driven by utilizing
the magnetostrictive deformation in the minor axis direction of the magnetostrictive element 1
thus flattened and thinned, the conventional giant magnetostrictive element using the
magnetostrictive deformation in the major axis direction Since the section coefficient of the giant
magnetostrictive element 1 largely increases as compared with the actuator, the bending stress
acting on the giant magnetostrictive element 1 decreases. Therefore, the strength or durability of
the giant magnetostrictive element 1 with respect to bending moment can be improved, and
breakage of the giant magnetostrictive element 1 due to bending moment can be prevented.
[0041]
That is, while the giant magnetostrictive element generally has the property of exhibiting high
strength against compressive load (for example, compressive strength = about 700 MPa), the
strength against tensile load is very small (for example, tensile strength = about 30 MPa) ). For
this reason, in a conventional giant magnetostrictive element formed into an elongated shaft
shape and using magnetostrictive deformation in the long axis direction, the section coefficient is
small with respect to the bending moment received from the driven member, and hence a
relatively small bending moment As a result, since a relatively large tensile stress acts on the
giant magnetostrictive element, it has been observed that the giant magnetostrictive element
tends to break. However, in the super magnetostrictive element 1 which is flattened and thinned
as described above and uses magnetostrictive deformation in the short axis direction, a relatively
large section coefficient can be obtained with respect to the bending moment received from the
driven member 11, so the action of the bending moment Tensile stress (bending stress = bending
moment / section coefficient) is reduced, and the resistance of the giant magnetostrictive element
1 to the bending moment is greatly improved. Therefore, breakage of the giant magnetostrictive
04-05-2019
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element 1 due to bending moment can be prevented.
[0042]
Further, in the flat-thinned super magnetostrictive element 1, the ratio of the element occupying
the magnetic path and the air is relatively reduced, as compared with the elongated
magnetostrictive element having a slender shaft. This makes it possible to reduce the
magnetomotive force of the field coil for generating the magnetic field strength necessary for
driving, and contributes to the power saving of the actuator using the giant magnetostrictive
element 1. The strength of the magnetic field is obtained by the magnetomotive force / the
length of the magnetic path, and the magnetomotive force is obtained by the coil conduction
current × the number of turns of the coil.
[0043]
FIG. 3 is a perspective view, a longitudinal sectional view, and a plan view showing a usage form
of the giant magnetostrictive element 1, and the giant magnetostrictive element 1 constitutes a
drive portion of an actuator.
[0044]
As shown in FIG. 3A, the super magnetostrictive element 1 is formed into a hollow cylindrical
shape having a hollow portion 4 of a circular cross section in the axial center portion.
The giant magnetostrictive element 1 is used as a component of the actuator 20, as shown in FIG.
3 (B). The actuator 20 includes a permanent magnet 21 for a bias magnetic field disposed in the
hollow portion 4 and a field coil 22 disposed outside the super magnetostrictive element 1. The
field coil 22 is disposed concentrically with the giant magnetostrictive element 1. A power source
24 for applying a voltage to the field coil 22 is connected to the field coil 22 via the field coil
conductor 23. By controlling the input current of the field coil 22, the magnetic field acting on
the giant magnetostrictive element 1 can be controlled, whereby the displacement of the giant
magnetostrictive element 1 in the material length direction can be variably controlled.
[0045]
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In the conventional super magnetostrictive element actuator in which the permanent magnet is
disposed outside the magnetostrictive element, since the attachment and detachment of the field
coil lead is difficult, the attachment and detachment of the field coil lead is an obstacle to mass
productivity or productivity improvement of the actuator. Although the structure of the actuator
20 in which the permanent magnet 21 is accommodated in the hollow portion 4 as shown in FIG.
3B, the attachment / detachment of the field coil conductor 23 to the field coil 22 is facilitated.
Therefore, according to such a structure, the manufacturing process of the actuator 20 can be
simplified, or the productivity of the actuator 20 can be improved.
[0046]
In addition, in the conventional giant magnetostrictive element actuator in which permanent
magnets are disposed at both ends of the axial giant magnetostrictive element, not only the
permanent magnet receives a load but also the axial length of the actuator increases and the
actuator becomes large However, according to the structure of the actuator 20 in which the
permanent magnet 21 is accommodated in the hollow portion 4, the actuator 20 can be made
flat and thin, and all the load can be supported by the giant magnetostrictive element 1.
[0047]
Furthermore, when the giant magnetostrictive element is formed with the same material amount,
or when the device outer diameter of the actuator 20 is set constant, the cylindrical structure or
hollow structure of the actuator 20 increases the outer diameter of the giant magnetostrictive
element 1. to enable.
For example, when the giant magnetostrictive element 1 is formed with the same material
amount, the outer diameter of the actuator 20 shown in FIG. 3 is larger than the outer diameter
of the actuator 20 shown in FIG. Since the expansion of the outer diameter of the giant
magnetostrictive element 1 leads to an increase of the section coefficient of the giant
magnetostrictive element 1, the resistance of the giant magnetostrictive element 1 to bending
moment is further improved.
[0048]
FIG. 4 is a longitudinal sectional view and a plan view showing another mode of use of the giant
magnetostrictive element 1, and the giant magnetostrictive element 1 constitutes a drive portion
of an actuator in the same manner as the mode of use shown in FIG.
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[0049]
As shown in FIG. 4, the actuator 20 has disk-shaped yokes 25 and 26 made of magnetic material,
and a spring clip 27 for prestressing.
In order to prevent the destruction of the giant magnetostrictive element 1 due to the inertial
force (tension load) during expansion and contraction, a prestress is applied to the giant
magnetostrictive element 1 and the giant magnetostrictive element 1 is used in advance in a
compressive stress state. In general, a method for preventing the occurrence of The prestress is
also applied to the giant magnetostrictive device 1 with the intention of increasing the maximum
magnetostriction amount of the giant magnetostrictive device 1 and improving the linearity of
the magnetic field-magnetostrictive characteristic. The spring clip 27 constitutes a prestressing
mechanism for giving such a prestress to the giant magnetostrictive element 1 and applies a
preload in the compression direction to the giant magnetostrictive element 1. The spring clip 27
is made of an elastically deformable material, and biases the upper and lower yokes 25 and 26 in
the approaching direction by an elastic restoring force generated by deformation at the time of
assembly.
[0050]
The conventional giant magnetostrictive element actuator adopts a configuration in which a
prestress disc spring or a compression coil spring is disposed at the shaft end of the giant
magnetostrictive element, and the height (axial length) of the actuator is approximately The axial
length is determined by the element length, the yoke thickness at both ends of the element, and
the dimensions of the prestressing mechanism, and the axial length must be set to a relatively
large dimensional value. As a result, the height (axial length) of the actuator is increased, which
has been a factor that hinders the reduction in thickness of the actuator. However, the spring clip
27 shown in FIG. 4 is an annular or band-like member provided with a locking portion 28 locked
to the outer peripheral portion of the disk-shaped yokes 25 and 26, and the actuator 20 has a
disk shape in its outer peripheral region. The outer edge portions of the yokes 25 and 26 are
sandwiched by one or more clip-like members. Therefore, the height (axial length) of the actuator
does not increase, and therefore, the height (axial length) of the actuator 20 can be set
approximately to the element length of the giant magnetostrictive element 1. That is, the prestressing mechanism constituted by the spring clip 27 does not become a factor to hinder the
flattening of the actuator 20, and the structure of such a prestressing mechanism is extremely
04-05-2019
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advantageous for flattening the actuator 20. .
[0051]
Also, the magnetic permeability of the giant magnetostrictive element 1 is only about eight times
that of air, and by sandwiching the giant magnetostrictive element 1 with disk-shaped magnetic
bodies (upper and lower disk-shaped yokes 25 and 26), a field coil is obtained. 22 and the
magnetic flux generated by the permanent magnet 21 can be introduced to the super
magnetostrictive element 1 effectively and uniformly. Since the magnetic resistance of the yoke
(iron) portion is usually extremely small compared to the giant magnetostrictive element 1 and
air, the length of the magnetic path is approximately that of the portion occupied by the giant
magnetostrictive element 1 and air in the magnetic path. It can be considered equal to the length.
[0052]
Furthermore, the configuration of the actuator 20 shown in FIG. 4 provides an independent
actuator unit that does not depend on the configurations of the support member 10 and the
driven member 11. That is, the open type super magnetostrictive element actuator 20 shown in
FIG. 3 does not have a prestress mechanism, and in the case where prestress is required, a
mechanism for applying a load to the support member 10 and the driven member 11 is provided.
Although it is necessary to apply a compressive load to the giant magnetostrictive element 1
through 10 and the driven member 11, the closed type giant magnetostrictive element actuator
20 shown in FIG. 4 has such a load applying mechanism as the spring clip 27 and the disc type
yoke. 25 and 26, and the same effects as in the configuration in which the materials of the
support member 10 and the driven member 11 are designed with a magnetic body are exhibited.
In other words, the closed type giant magnetostrictive element actuator 20 shown in FIG. 4 has a
prestress mechanism and a magnetic yoke as constituent elements of the apparatus itself, and
has a configuration in which the function required as the actuator is completed in a single unit.
[0053]
FIG. 5 is a partial perspective view of a mobile phone provided with the actuator 20 shown in
FIG. 3 or FIG.
[0054]
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The display part 31 of the mobile telephone 30 is shown by FIG.
The mobile phone 30 is a mobile phone of a general type in which the display unit 31 is
connected to the operation unit 33 by the movable shaft 32. However, the mobile phone 30
includes a relatively large display screen 35 in which the AV function is emphasized. The display
screen 35 is composed of an LCD panel 37 for displaying an image and a transparent surface
panel 36 covering the LCD panel 37 from the outside, and the surface panel 36 and the LCD
panel 37 are separated by a slight distance. There is. The surface panel 36 is larger than the LCD
panel 37, and a screen margin 38 not associated with the image of the LCD panel 37 is formed
on the top of the surface panel 36.
[0055]
The actuator 20 is disposed between the surface panel 36 and the LCD panel 37 in the area of
the screen margin 38. The front surface of the actuator 20 is bonded to the back surface of the
surface panel 36, and the back surface of the actuator 20 is bonded to the screen outside area or
frame area 39 of the LCD panel 37. The out-of-screen area or frame area 39 of the LCD panel 37
constitutes the support member 10 (FIGS. 2 to 4), and the screen margin 38 of the surface panel
36 is the driven member 11 (FIGS. 2 to 4). Configure.
[0056]
The power supply of the mobile phone 30 is used as the field coil power supply 24 of the
actuator 20, and the input current of the field coil 22 of the actuator 20 is controlled by the
acoustic control means (not shown) of the mobile phone 30. The giant magnetostrictive element
1 of the actuator 20 undergoes magnetostrictive deformation under the control of the acoustic
control means. The surface panel 36 protecting the LCD panel 37 is a rigid body having a
relatively high rigidity, but the actuator 20 exerts a high generated force F as described above to
divide and vibrate the surface panel 36. The surface layer panel 36 functions as an acoustic
diaphragm, and the vibration of the surface layer panel 36 is air-borne as acoustic energy and is
viewed by the user.
[0057]
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17
As mentioned above, although the preferred embodiment of the present invention was described
in detail, the present invention is not limited to the above-mentioned embodiment, and various
changes or modifications may be made within the scope of the present invention described in the
claims. It is possible.
[0058]
For example, the cross section of the giant magnetostrictive element 1 is not limited to a circular
cross section, and may be set to a square cross section, a polygonal cross section, an elliptical
cross section, or the like.
[0059]
Further, the shape, number and position of the spring clip 27 can be appropriately changed in
design according to the form of the actuator 20.
[0060]
Furthermore, a plurality of actuators may be disposed between the surface panel 36 and the LCD
panel 37.
[0061]
The present invention is applied to an actuator for driving a relatively high rigidity driven
member.
In particular, the actuator of the present invention has a flat and thin outer shape, can be
incorporated into a narrow space, and generates a high driving force.
For example, the actuator of the present invention can be incorporated into the screen or the like
of a portable device to drive a screen surface plate having a relatively high rigidity, and the
surface plate can be used as an acoustic diaphragm.
[0062]
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18
It is a diagram which shows the characteristic of the generation distortion and generation ¦
occurrence ¦ production stress of a giant magnetostriction element.
FIG. 1A is a perspective view and a longitudinal cross-sectional view showing a giant
magnetostrictive element according to an embodiment of the present invention.
It is a perspective view, a longitudinal cross-sectional view, and a top view which show the usage
form of a super-magnetostrictive element, and a super-magnetostrictive element comprises the
drive part of an actuator. It is the longitudinal cross-sectional view and top view which show the
other usage forms of a super-magnetostrictive element, and a super-magnetostrictive element
comprises the drive part of an actuator similarly to the use form shown in FIG. FIG. 5 is a partial
perspective view of a mobile phone provided with the actuator shown in FIG. 3 or 4.
Explanation of sign
[0063]
Reference Signs List 1 giant magnetostrictive element 2, 3 end face 4 hollow portion 10 support
member (base) 11 driven member 12 space 20 actuator 21 permanent magnet 22 field coil 23
field coil lead 24 power source 25, 26 disc-shaped yoke 27 for prestressing Spring clip 28
Locking part 30 Mobile phone 31 Display part 32 Movable shaft part 33 Operation part 35
Display screen 36 Surface panel 37 LCD panel 38 Screen margin part 39 Screen outside area or
frame area
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