close

Вход

Забыли?

вход по аккаунту

?

JPS5784498

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 JPS5784498
Description 1, title of the invention
Sound wave lens
3. Detailed Description of the Invention The present invention relates to an acoustic lens used for
focusing, diffusing or redirecting acoustic waves. In the past, reflectors and horns have often
been used to focus, diffuse or redirect sound waves. An acoustic lens having an optical concave
lens shape, for example, is attached to the tip of a probe such as an ultrasonic flaw detector and
the like transmits ultrasonic waves transmitted through the lens from its concave surface and
this is transmitted to the subject. There is also known an acoustic lens which is made to converge
at one point. However, all of these have the effect of focusing and diffusing the sound wave by
shaping the surface on which the sound wave is incident, reflected or emitted into a
predetermined spherical or other curved surface. EndPage: In the present invention, on the other
hand, the lens main member itself is partially made of a medium having different sound
velocities, thereby providing a lensing effect. Is intended to provide an acoustic lens capable of
focusing, diffusing, and changing sound waves independently. Therefore, according to the
present invention, for example, the desired lens effect can be obtained even if it is a simple flat
plate, so that it can be used in the field where the conventional acoustic lens is used from its
shape and its installation is difficult An acoustic lens is provided. In addition, by using the lens
member of the present invention for a conventional acoustic lens or horn, the efficiency can be
further improved.
Sound wave lens
03-05-2019
1
Hereinafter, the present invention will be described in detail using the drawings. FIG. 1 is a crosssectional view showing the operation principle of an embodiment of an acoustic lens according to
the present invention, and FIG. 2 is an acoustic velocity with respect to the amount of hot
pressure deformation of graphite used as an example of the material of the acoustic lens of the
present invention. FIG. 3 is a cross-sectional view showing one example in the case where the
acoustic wave lens according to the present invention is applied to a horn. The acoustic lens 1 of
the present invention shown in FIG. 1 is a circular flat plate lens having a central axis 1a in the
figure, and its density gradually increases from its central portion 1b to its outer peripheral
portion 1c. It is configured to increase. However, as shown in the figure, assuming that plane
wave 2 is perpendicularly incident from the left side of this lens, the wavefront at the time when
a minute time Δt after incidence is given is an infinite number of incident points on the lens
according to the principle of Huygens. In the case of this lens, the density increases and the
speed of sound increases as it gets closer to the outer periphery, so the minuteness is small. The
wave front after time Δtg is a curved surface as shown by 2a in the figure, although it is drawn
somewhat exaggerated. Thereafter, the wavefront at the time when the minute time Δt passes
further becomes the envelope surface 2b of the innumerable waves whose centers are the
innumerable points on the curved surface 2a and the distance transmitted in the minute time Δt
is radius. The size of the wavefront 2a is also larger than that of the wavefront 2a. Therefore, the
wavefront of the plane wave 2 incident from the left side of the lens gradually curves in the
process of passing through the lens, and finally becomes a curved surface as shown by 2T in the
figure and is emitted from the right side of the lens. Converge on the Therefore, even if this
acoustic lens 1 is flat, it has the same action as the optical convex lens on the acoustic wave. In
addition, it will be easily understood that, on the contrary, for example, if the density of the
central portion is high and the density decreases toward the peripheral portion, one having a
function as a concave lens can be obtained. Although the lens 1 in FIG. 1 is described above as
having a circular flat plate shape, it may be formed into any shape within a range that does not
lose the function of the lens other than the square depending on the purpose of use. Since
graphite is mentioned as one of the desirable materials to be used when producing the acoustic
lens of the present invention partially different in density as described above, its sound velocity
characteristics are shown in the graph of FIG. Explain. The graphite material usually provided is,
for example, a mold made of GL coke of 100 mesh as carbon aggregate, and (5) to which
petroleum hard bite of about 80 fixed carbon is added as a binder in a weight ratio of about 15
inches by weight ratio , Which is obtained by hot-pressing and firing it by, for example, a currentcarrying (discharge) sintering method or the like, and its density is usually about 70 inches.
The horizontal axis of the graph of FIG. 2 indicates the amount of deformation of the profile in
the pressing direction when the density is further increased by crushing such graphite by hot
pressing. When the deformation I ° is 10 inches, the density reaches about 90%. On the other
hand, the vertical axis of the graph indicates the velocity of sound (20 ° C., unit m / 5 ec) i
03-05-2019
2
passing through such graphite. As can be seen from this graph, the velocity of the sound wave
passing through it is about 1700 m / sec when the density of graphite is about 70 cm, but the
sound velocity reaches 4300 m / sec when the density is more than 90 cm It is understood that
the speed of sound changes significantly according to the change in density. Therefore, for
example, if the lens 1 shown in FIG. 1 is made of graphite and the density thereof gradually
changes from the central portion to the outer peripheral portion, (6) EndPage: 2 an acoustic lens
having desired lens characteristics is obtained It is possible to The preparation method itself is
not so complicated, and an example will be described below. That is, since graphite can be
produced by hot-pressure-firing a carbon aggregate powder to which a binder is added as
described above, when producing the acoustic lens of the present invention, for example, When
filling the wood to be graphitized, the central part is filled with a base material containing carbon
powder with uniform particle size, and the outer base part is gradually filled with a base material
containing carbon powder with fine particle size and hot pressure firing is performed If so,
graphite having a higher density as it goes to the outer periphery can be obtained. Alternatively,
tar or pitch used as a binder may be used, and one different in fixed carbon content from the
central portion to the outer peripheral portion may be used. Furthermore, metal powders such as
iron, cobalt, nickel, chromium, copper, silver and the like, or ceramic powders are added to the
base consisting of carbon aggregate powder and a binder so that the amount of addition thereof
differs partially, and hot It may be made to carry out pressure dissolution. As the sintering
method, various conventionally known hot press (7) methods can be used. Among them, for
example, the carbon aggregate powder is partially described as described above when the
sintering method is used. The mold is filled with a base material of varying particle size, fixed
carbon content of binder, addition amount of additive powder such as metal, etc., and this is
electrified, pressed between the opposing bunch electrodes of the sintering apparatus and
pressed. \ It conducts electricity and performs graphitization processing. The conduction current
in this case may be direct current or alternating current of commercial frequency, but in
consideration of overall uniform heating and thermal efficiency of the sintered body, it is
preferable to use superimposed current of direct current and alternating current, and the
alternating current It is recommended to set the frequency of the current to 0.5 to 2 KE (z, and
set the weight ratio of direct current to alternating current in the range of 1: 1 to 4: 1.
The substrate filled in the mold is pressurized with a punch electrode at a pressure of 10 h / cr 1
r, and then the passage of time is started, and after several seconds, the pressure is increased to
200 to 1,000 Kq / −. Conduct electric sintering for 30 to 150 seconds. The amount of power at
this time is as follows. It is about OKW. Of course, the frequency of the alternating current and
the weight with the direct current (8) are appropriately selected and determined, and in some
cases, the pressurizing force and the energizing power are changed in several steps during a
series of energizing times. It is also good. Alternatively, it may be divided into primary sintering
and secondary sintering, and the desired portion of the primary sintered body may be
impregnated with high molecular weight hydrocarbon and secondarily sintered 9 Graphite
03-05-2019
3
materials having partially different densities may be obtained. Thus, as described above, graphite
is particularly useful as the material of the acoustic lens of the present invention in that the
change in sound velocity with respect to the change in density is remarkable, but this is
necessarily limited to graphite Any material can be used as long as it is a material from which
molded articles whose density is partially changed can be obtained, specifically, a material that is
relatively easy to be hot pressed. That is, representative ones among them are synthetic resin,
ceramic, sinterable end and the like, and by using these alone or in combination, it is possible to
make a desired acoustic lens. . As the application field of the acoustic lens of the present
invention as shown in FIG. 1, all fields in which a conventional acoustic lens was used can be
mentioned, but in addition, for example, the acoustic wave is transmitted between a plurality of
members. In the case of the conventional acoustic lens, since the outer shape is a curved surface,
it is an interval to be in close contact with a normal member, whereas the acoustic lens of the
present invention has a lens function even if the outer shape is a simple plane. It is possible to
easily make close contact with the members and to allow the transmission between the members
with the loss of the sound wave being minimized. It is also extremely useful when attached to the
front of a sonar ultrasonic oscillator to form a highly directional sound field. Next, another
modified embodiment of the acoustic wave lens of the present invention will be described with
reference to FIG. FIG. 3 shows an example in which the acoustic lens of the present invention is
applied to a horn used to transmit and concentrate ultrasonic waves from an ultrasonic
transducer to a work portion in, for example, an ultrasonic processing machine or ultrasonic
welding machine. It shows. In FIG. 3, 3 is an ultrasonic transducer such as a magnetostrictive
element, and 4 is a conical horn whose bottom surface is in contact with the vibration surface of
the ultrasonic EndPage: 3 transducer 3.
The density of the axial central portion 4a of the horn 4 is the smallest, and the density is
increased stepwise from the intermediate portion 4b to the outer peripheral portion 4c.
Therefore, also in this case, as in the case of the acoustic lens shown in FIG. 1, the ultrasonic
wave incident from the bottom of the horn is concentrated on the tip 4d portion by the lens
action, and the material is uniform. A horn effect more efficient than the manufactured
conventional horn can be obtained. Needless to say, the invention can be applied not only to
conical horns but also to para-poly horns, index horns and the like. Furthermore, it is a matter of
course that the acoustic wave lens of the present invention can also be used by shaping the
incident and outgoing surfaces of the acoustic wave into a curved surface as in a conventional
acoustic lens. In that case, even if the curved surface has the same radius of curvature as that of
the conventional acoustic lens, it is possible to produce one having a focal length shorter than
that of the conventional acoustic lens made of a uniform material. It is also possible to provide a
sonic lens with a focal length that was not possible with conventional sonic lenses due to the
limit of the radius of curvature. Since the present invention is configured obliquely, according to
the present invention, it can be used in the field where the conventional acoustic lens can not be
used, and the extremely useful acoustic lens can increase the efficiency of the conventional
03-05-2019
4
acoustic lens and horn. It is provided.
4. Brief description of the drawings Fig. 1 is a cross-sectional view showing the working principle
of an embodiment of the acoustic lens according to the present invention, and Fig. 2 is the heat
of graphite used as an example of the material of the acoustic lens of the present invention. FIG.
3 is a graph showing the sound velocity characteristics with respect to the inter-pressure
deformation amount, and FIG. 3 is a [1 + plane view] showing one embodiment in the case of
applying the acoustic lens according to the present invention to a horn. 1 · · · · · · · · · · Disc-like
lens. · · · · · · · · · Plane wave J · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·
· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ultrasonic wave 4 · · · · · · · · · · Conical horn EndPage: 4
03-05-2019
5
Документ
Категория
Без категории
Просмотров
0
Размер файла
15 Кб
Теги
jps5784498
1/--страниц
Пожаловаться на содержимое документа