U.S. patent application number 15/662977 was filed with the patent office on 2018-02-01 for metal molded body manufacturing apparatus by electromagnetic stirring.
The applicant listed for this patent is AIDA ENGINEERING, LTD.. Invention is credited to Masaharu MURAMATSU, Shogo SHIBASAKI, Masataka YAHARA.
Application Number | 20180029111 15/662977 |
Document ID | / |
Family ID | 59752092 |
Filed Date | 2018-02-01 |
United States Patent
Application |
20180029111 |
Kind Code |
A1 |
MURAMATSU; Masaharu ; et
al. |
February 1, 2018 |
METAL MOLDED BODY MANUFACTURING APPARATUS BY ELECTROMAGNETIC
STIRRING
Abstract
There is provided a metal molded body manufacturing apparatus
for electromagnetically stirring metallic molten metal and molding
a metal molded body. The metal molded body manufacturing apparatus
includes: a die having an inclined side wall; and a moving magnetic
field generation section that stirs the molten metal in the die,
wherein the moving magnetic field generation section includes a
magnetic body, and a coil wound around the magnetic body as a
center, and an end surface of the magnetic body is disposed in
parallel to an inner surface of the side wall.
Inventors: |
MURAMATSU; Masaharu;
(Kanagawa, JP) ; SHIBASAKI; Shogo; (Kanagawa,
JP) ; YAHARA; Masataka; (Kanagawa, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
AIDA ENGINEERING, LTD. |
Kanagawa |
|
JP |
|
|
Family ID: |
59752092 |
Appl. No.: |
15/662977 |
Filed: |
July 28, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F27D 27/00 20130101;
B22D 11/11 20130101; B22D 1/00 20130101; F27D 2003/0054 20130101;
C21C 7/0075 20130101; B22D 11/115 20130101; B22D 11/003 20130101;
B22D 27/02 20130101 |
International
Class: |
B22D 11/115 20060101
B22D011/115; B22D 11/00 20060101 B22D011/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 28, 2016 |
JP |
2016-148371 |
Claims
1. A metal molded body manufacturing apparatus for
electromagnetically stirring metallic molten metal and molding a
metal molded body, the metal molded body manufacturing apparatus
comprising: a die including a side wall having an inclined inner
surface; and a moving magnetic field generation section that is
disposed along an outer periphery of the die, and stirs the molten
metal in the die, wherein the moving magnetic field generation
section includes a magnetic body, and a coil wound around the
magnetic body as a center, and an end surface of the magnetic body
is disposed such that a gap between the end surface of the magnetic
body and the inner surface of the side wall becomes uniform.
2. The metal molded body manufacturing apparatus according to claim
1, wherein an inclination of the side wall serves as a draft angle
for extracting the metal molded body.
3. The metal molded body manufacturing apparatus according to claim
2, wherein the draft angle is 1.degree. to 9.degree..
4. The metal molded body manufacturing apparatus according to claim
1, wherein the side wall has a pair of facing walls that face each
other, the moving magnetic field generation section is provided
along each of the facing walls, and the moving magnetic field
generation sections generate respective moving magnetic fields in
reverse directions from each other so as to generate a vortex in
the molten metal.
5. The metal molded body manufacturing apparatus according to claim
1, further comprising: an inclined plate to which a base, and the
moving magnetic field generation section are fixed; and an
inclination adjusting mechanism that adjusts an inclination of the
inclined plate to the base so as to uniform the gap between the end
surface of the magnetic body and the inner surface of the side
wall, the inclination adjusting mechanism being disposed between
the inclined plate and the base.
6. The metal molded body manufacturing apparatus according to claim
1, wherein the end surface of the magnetic body of the moving
magnetic field generation section extends beyond an upper surface
of the molten metal put into the die from below a bottom of the
die.
7. The metal molded body manufacturing apparatus according to claim
1, wherein the die has a curved shape in plan view, an additional
magnetic body member is provided in the end surface of the magnetic
body of the moving magnetic field generation section, and an end
surface of the additional magnetic body member is a curved surface
along a curved inner surface of the die.
Description
BACKGROUND OF THE INVENTION
Field of the Invention
[0001] The present invention relates to an apparatus for
manufacturing a metal molded body by stirring molten metal in a
die.
Description of Related Art
[0002] Conventionally, as one of technologies for molding aluminum
alloy or the like, a die casting method for pressurizing and
injecting molten metal into a die to obtain a molded article having
a predetermined shape is used, and in a case where molten metal is
used, problems, such as a short life of the die, insufficient
quality of a product due to generation of shrinkage, mold cavity,
or the like, are pointed out.
[0003] Additionally, conventionally, as a method for molding a
metal molded body while stirring molten metal in a die, and a
method for further machining an obtained metal molded body by a
press machine, a rheocasting process is known. In this case, the
die is generally provided with a draft angle, and therefore work
for extracting a manufactured metal molded body to transpose the
metal molded to a molding die such as a press machine in a next
process is easy. Of course, the metal molded body is sometimes used
as a product without change.
[0004] Furthermore, an aluminum structure used in a vehicle body or
the like is often thin and long, and is bent. In a case where such
a thin and long structure is molded with aluminum, the shape of a
stirring die is made to be thin and long in order to approximate
the shape of a metal molded body before press molding into the
structure.
[0005] JP 5352236 B1, JP 2009-74103 A, and JP 2007-144501 A each
describe an apparatus for performing electromagnetic stirring for
molten metal. An inner peripheral surface of a melting furnace
(pot) of the apparatus is formed in a cylindrical shape, and molten
metal is stirred along the circular inner peripheral surface.
[0006] In addition, an apparatus described in JP 2006-289448 A is
used for a continuous casting facility, and linear type
electromagnetic stirring apparatuses are provided on an outside so
as to face both linear side walls.
[0007] Additionally, JP 2006-289448 A and JP 2006-289476 A each
disclose a structure of a linear type electromagnetic stirring
apparatus.
[0008] Furthermore, for example, relation between a gap and
electromagnetic force is considered in "Electromagnetic Coil
Designed by Magneto-Hydro-Dynamic Simulation, shinnittetsu giho
vol. 379", and "Development of a Simulation Model for
Electromagnetic Stirring in Melting Furnace, Furukawa-sky Review
No. 3, 2007".
SUMMARY OF THE INVENTION
Problem to be Solved by the Invention
[0009] Molten metal which is put into a die generally starts
cooling from a moment of this putting. Therefore, time for stirring
until the molten metal is solidified is about 10 seconds at most.
That is, it is important to how efficient the molten metal is
stirred for a short time until the molten metal is solidified.
[0010] Herein, the above die is provided with the draft angle for
extracting the manufactured metal molded body.
[0011] However, thrust of electromagnetic stirring which acts on
the molten metal is significantly changed at a position in the
depth direction in the die, depending on this draft angle. For
example, as illustrated in FIG. 1B, when an effective gap G2 at a
lower end of the die is twice an effective gap G1 at an upper end
of the die, magnetic flux density is about 30%, there is a
possibility that the thrust falls to ten percent (square of 0.3)
(refer to "Electromagnetic Coil Designed by Magneto-Hydro-Dynamic
Simulation, shinnittetsu giho vol. 379", and "Development of a
Simulation Model for Electromagnetic Stirring in Melting Furnace,
Furukawa-sky Review No. 3, 2007"). Therefore, a large difference in
thrust is generated between the upper end and the lower end of the
die, and efficiency of stirring becomes low in the vicinity of the
lower end.
[0012] The difference in thrust cannot be ignored, when the
stirring time of about 10 seconds 10 is considered. In addition to
the above, particularly, in a case of the metal molded body of such
a thin and long, and bent structure as to be used for a vehicle
body or the like, the shape of the die is shapeless or is not a
usual shape, and has a branch section or the like in the middle.
The shape of such a die is one of causes of hindering a flow of
stirring, and cannot be ignored in view of efficiency of stirring,
along with the gap of the draft angle as described above, when all
the stirring processes for about 10 seconds are considered,
[0013] Therefore, an object of the present invention is to provide
a metal molded body manufacturing apparatus capable of efficiently
stirring molten metal.
Means to Solve the Problem
[0014] (1) A metal molded body manufacturing apparatus of the
present invention is a metal molded body manufacturing apparatus
for electromagnetically stirring molten metal, and molding a metal
molded body, the metal molded body manufacturing apparatus
including: a die including a side wall having an inclined inner
surface; and a moving magnetic field generation section that is
disposed along an outer periphery of the die, and stirs the molten
metal in the die, wherein the moving magnetic field generation
section includes a magnetic body, and a coil wound around the
magnetic body as a center, and an end surface of the magnetic body
is disposed such that a gap between the end surface of the magnetic
body and the inner surface of the side wall becomes uniform.
[0015] Herein, "the gap between the end surface of the magnetic
body and the side wall inner surface is uniform" means that the end
surface of the magnetic body of the moving magnetic field
generation section is parallel to the inner surface of the side
wall, and is a concept including a case where the end surface of
the magnetic body is not parallel to an outer face.
[0016] Furthermore, the metal molded body is a concept including
metal that is obtained by cooling molten metal to be brought into a
solid-liquid coexistent state, includes metal that is further
cooled to be solidified, including metal that is obtained by
further heating solid metal to be brought into a solid-liquid
coexistent state, and including a primary molded body that is
machined in a next process to become a product, and a final molded
body that becomes a product without change.
[0017] (2) In such a metal molded body manufacturing apparatus, an
inclination of the side wall inner surface preferably serves as a
draft angle for extracting the metal molded body.
[0018] (3) The draft angle is preferably 1.degree. to
9.degree..
[0019] (4) The side wall preferably has a pair of facing walls that
face each other, the moving magnetic field generation section is
preferably provided along each of the facing walls, and the moving
magnetic field generation sections preferably generate respective
moving magnetic fields in reverse directions from each other so as
to generate a vortex in the molten metal.
[0020] (5) The metal molded body manufacturing apparatus preferably
further includes: a base; an inclined plate to which the moving
magnetic field generation section is fixed; and an inclination
adjusting mechanism that adjusts an inclination of the inclined
plate to the base so as to uniform the gap between the end surface
of the magnetic body and the side wall inner surface, the
inclination adjusting mechanism being disposed between the inclined
plate and the base.
[0021] (6) The end surface of the magnetic body of the moving
magnetic field generation section preferably extends beyond an
upper surface of the molten metal put into the die from below a
bottom of the die.
[0022] (7) The die preferably has a curved shape in plan view, an
additional magnetic body member is preferably provided in the end
surface of the magnetic body of the moving magnetic field
generation section, and an end surface of the additional magnetic
body member is preferably a curved surface along the curved inner
surface of the die.
Effect of the Invention
[0023] (1) In the metal molded body manufacturing apparatus of the
present invention, the end surface of the moving magnetic field
generation section is disposed in parallel to the inclined inner
wall surface of the die, and the gap (distance) between this end
surface and the inner surface of the die is made the same, and
therefore a difference of thrust in the vertical direction of the
wall surface is unlikely to be generated.
[0024] Therefore, while the molten metal is stirred by a die having
a shape close to a final product, residual gas is discharged, and
growth of a crystal is prevented, the molten metal can be
isothermally cooled as a whole to be solidified.
[0025] (2) In such a manufacturing apparatus for the metal molded
body, in a case where the inclination of the side wall serves as
the draft angle for extracting the metal molded body, the metal
molded body can be easily extracted, which is effective.
[0026] Additionally, the draft angle is provided, and therefore the
penetration depth of the moving magnetic field approaches the
center of the die toward a lower surface of the die. Therefore, a
strong vortex generates closer to the center toward the lower
surface of the die, and a downward flow which draws the molten
metal from the upper surface generates. Dislocation (convection) of
an upper layer and a lower layer of the molten metal proceeds by
this vortex to facilitate discharge of residual gas.
[0027] (3) In a case where the draft angle is 1.degree. to
9.degree., such an angle is easy to use as the draft angle. In
addition, the convection can be generated.
[0028] (4) In a case where the side wall has a pair of the facing
walls that face each other, the moving magnetic field generation
section is provided along each of the facing walls, and these
moving magnetic field generation sections generate respective
moving magnetic fields in reverse directions from each other so as
to generate a vortex in the molten metal, it is possible to enhance
efficiency of stirring even in an oblong die.
[0029] Additionally, growth of a metal crystal is hindered by the
vortex, resulting in a dense structure.
[0030] (5) In a case where the metal molded body manufacturing
apparatus further includes a base, an inclined plate to which the
base and the moving magnetic field generation section are fixed and
the inclination adjusting mechanism that adjusts inclination of the
inclined plate to the base such that the end surface of the
magnetic body are parallel to the side wall, the inclination
adjusting mechanism being disposed between the inclined plate and
the base, the inclination of the moving magnetic field generation
section can be adjusted to the draft angle when the draft angle of
the die is changed.
[0031] (6) In a case where the end surface of the magnetic body of
the moving magnetic field generation section extends beyond the
upper surface of the molten metal put into the die from below the
bottom of the die, the whole of the molten metal can be reliably
moved, and therefore stirring efficiency is high.
[0032] (7) In a case where the die has the curved shape in plan
view, the additional magnetic body member is provided in the end
surface of the magnetic body of the moving magnetic field
generation section, and the end surface of the additional magnetic
body member is the curved surface along the curved inner surface of
the die, it is possible to form a smooth flow along the curved
surface.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] FIG. 1A is a sectional view illustrating a metal molded body
manufacturing apparatus according to an embodiment of the present
invention, and FIG. 1B is a sectional view illustrating an example
for comparison with the apparatus of FIG. 1A.
[0034] FIG. 2A is a plan view illustrating of a die according to
the embodiment, and FIG. 2B is a sectional view taken along a A-A
of the die of FIG. 2A.
[0035] FIG. 3 is a schematic plan view illustrating moving magnetic
field generation sections and the die.
[0036] FIG. 4A and FIG. 4B each are a schematic view illustrating a
state where a coil is wound around a core back.
[0037] FIG. 5A and FIG. 5B each are a schematic view illustrating a
state where the coil is wound between slots.
[0038] FIG. 6 is a side view illustrating a metal molded body
manufacturing apparatus according to another embodiment.
[0039] FIG. 7A is a front view illustrating a moving magnetic field
generation section according the other embodiment and FIG. 7B is a
bottom view of the moving magnetic field generation section of FIG.
7A.
[0040] FIG. 8 is a plan view illustrating a manufacturing apparatus
according to yet another embodiment.
[0041] FIG. 9A is a plan view illustrating a state where an
additional magnetic body is detached from the moving magnetic field
generation section of FIG. 8, and FIG. 9B is a plan view of an
additional magnetic body member of FIG. 8, and FIG. 9C is a plan
view illustrating an additional magnetic body member according to
another embodiment.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
First Embodiment
1. Summary
[0042] A manufacturing apparatus for a metal molded body of the
present invention (hereinafter simply referred to as a
manufacturing apparatus) will be described with reference to FIG.
1. A manufacturing apparatus 1 illustrated in FIG. 1 is an
apparatus that stirs molten metal, which is put into a die 2, by
moving magnetic field generation sections 3, and molds a metal
molded body in the die.
[0043] The metal molded body manufactured by this manufacturing
apparatus 1 is subjected to machining for making a press-formed or
press-molded article by, for example, a press apparatus (not
illustrated) in a next process, or is used as a final molded body
without change.
2. Manufacturing Apparatus 1
[0044] More specifically, the manufacturing apparatus 1 includes
the die 2 having a side wall 5 having an inclined inner surface,
and a moving magnetic field generation section 3 that stirs the
molten metal in the die 2. An end surface 3a of a magnetic body of
the moving magnetic field generation section 3 is disposed such
that a gap G (refer to FIG. 1A) with an inner surface 5c of the
side wall (hereinafter referred to as an inner wall surface)
becomes uniform. The end surface 3a and the inner wall surface 5c
are parallel or substantially parallel to each other.
(As to Die 2)
[0045] The die 2 is preferably formed of, for example, a material
having low magnetic permeability and a higher melting point than
that of the molten metal which is metal put into the die. In this
embodiment, stainless steel is used.
[0046] The die 2 (refer to FIG. 2B) has a bottom 4, and a side wall
5 extending upward from a peripheral edge of the bottom 4. The side
wall 5 inclines outward toward an opening side so as to extract the
metal molded body. The thickness of the side wall 5 is generally
uniform, but may not be uniform. In a case where the thickness is
not uniform, at least the inner surface only needs to incline
outward toward the opening side. The angle of the inclination only
needs to be a draft angle for extracting the metal molded body to
an axis of the die 2 (an axis perpendicular to a surface of the
bottom, or a vertical axis). For example, the draft angle is
1.degree. to 9.degree., and preferably 5.degree. to 7.degree..
(Shape of Die)
[0047] As illustrated in FIG. 2A, in this embodiment, the die 2
has, for example, a long oval shape or an athletics track shape in
plan view. That is, the side wall 5 of the die 2 includes a pair of
facing walls 5a, 5a facing each other. Respective both ends of the
straight facing walls 5a, 5a are connected to the semicircular
sections 5b, 5b, so that the above long oval shape or athletics
track shape is formed.
[0048] FIG. 2B illustrates a sectional view of FIG. 2A. The side
wall 5 inclines so as to expand toward the opening side. In this
embodiment, the bottom 4 is flattened.
(Molten Metal)
[0049] The molten metal which is put into the die 2 is metal such
as aluminum alloy that is melted.
(Moving Magnetic Field Generation Section 3)
[0050] Returning to FIG. 1A, the moving magnetic field generation
sections 3 each include, for example, a magnetic body 6
(hereinafter referred to as a core), and coils 7 wound around the
core 6 as a center. As illustrated in FIG. 1A, the moving magnetic
field generation sections 3, 3 (refer to two-dot chain lines of
FIG. 2A) are disposed such that the end surfaces of the cores 6 are
parallel to the inner surfaces of the facing walls 5a, 5a of the
side wall and there is clearances between the end surfaces of the
core 6 and the outer surfaces of the side wall.
[0051] The end surfaces of the cores 6 of the moving magnetic field
generation sections 3 each extend from a position below the bottom
4 of the die 2 to a position above an upper surface of the molten
metal put into the die. Therefore, it is possible to reliably move
the whole of the molten metal.
(Magnetic Bodies 6 and Coils 7)
[0052] Returning to FIG. 1A, the magnetic bodies 6 and the coils 7
are conventionally known ones. For example, each magnetic body 6
employs, for example, a silicon steel sheet, and is formed by
stacking thin sheets because of reduction in influence of an eddy
current or the like.
[0053] In each magnetic body 6, a plurality of slots 8 are formed
on the side wall side of the die 2 at equal intervals (refer to
FIG. 4A). Each slot 8 has a coil 7 wound therearound.
(Principle and the Like)
[0054] FIG. 3 schematically illustrates the manufacturing apparatus
1. In the figure, the three moving magnetic field generation
sections 3 are lined to be connected on one side of the die 2. A
power source is a three-phase alternating current (AC). Three-phase
ACs U, W, V are sequentially applied to coils of terminal symbols
R, S, T. Then, a magnetic field (direction of an arrow H) that
moves in parallel to the facing wall 5a of the side wall 5 is
generated in the die 2. Specifically, a +U-phase current, a
-W-phase current, a +V-phase current, a -U-phase current, a
+W-phase current, and a -V-phase current are applied to the
respective coils 7 illustrated in FIG. 3 in this order from the
left of the figure. In these three-phase ACs, phases of the
+U-phase, the +V-phase, and the +W-phase are AC currents shifted by
120.degree. in order, and currents of the -V-phase, the -W-phase,
and the -U-phase are opposite directions. As to the current flow
direction, it is defined that the flow direction from the front to
the back of the paper sheet is positive. When a current flows in
the positive direction, a clockwise magnetic flux with the coil as
the center generates, and when a current flows in the reverse
direction, a counterclockwise magnetic flux generates. The
magnitude of the magnetic flux density increases as a current value
of the coil increases.
[0055] Accordingly, when a current is applied to the coil, a
combined magnetic flux density distribution moves from the left to
the right (see an arrow .phi.) with lapse of time. That is, a
moving magnetic field that moves from the left to the right along
the longitudinal direction of the core 6 is formed. Consequently,
an induced current is generated in the molten metal, and an
electromagnetic force (Lorentz force) is generated in the molten
metal. Then, driving force (refer to arrows H1, H2, H3) that
provides flows to follow the motion of the moving magnetic field is
applied in the molten metal.
[0056] Symbol O denotes a neutral point.
[0057] FIG. 4A is a plan view of the moving magnetic field
generation section 3 of FIG. 1A. A winding method illustrated in
the figure is a core back winding method. The cores 6 of the moving
magnetic field generation sections 3 each are formed in a
comb-tooth shape, and the coils 7 are wound between the teeth of
each core (the above slots 8).
[0058] The slots are filled with the coils (coil conductors) 7.
Each core 6 is composed of a rectangular column shaped yoke (core
back) 6a, and teeth 9 each having an end fixed to dovetail-shaped
grooves 6b formed in the yoke. The number of the teeth 9 is seven,
the number of the coils 7 to be wound around the yoke between the
teeth is six, and all the coils are wound in the same direction.
Therefore, in a case where a current enters from an initially wound
coil, and a case where a current enters from a finally wound coil,
the polarities are reverse. Each slit 8a that is opened toward the
die 2 is formed between the adjacent teeth 9, 9. The yoke 6a and
the teeth 9 are each formed of a core formed by superimposing a
large number of thin sheets of silicon steel sheets, and these may
be integrated.
[0059] In the moving magnetic field generation section 3, as a
minimum unit for smoothly generating a moving magnetic field by a
three-phase power supply, the six slots 8 are used as the minimum
unit. In a case where the further reduced number of the slots is
used as the minimum unit, balance is kept by mutual magnetic
coupling.
[0060] FIG. 5A illustrates a moving magnetic field generation
section 3 according to another embodiment. A winding method
illustrated in the figure is an inter-slot winding method. A
U-phase coil passes through a leftmost slot and a fourth slot so
that the coil is wound around three teeth between the leftmost slot
and the fourth slot. Similarly, a V-phase coil passes through a
second slot and a fifth slot so that the coil is wound around three
teeth between the second slot and the fifth slot. A W-phase coil
passes through a third slot and a sixth slot so that the coil is
wound around three teeth between the third slot and the sixth slot.
These three kinds of coils are overlapped to intersect with each
other on the lateral side of the core 6, as illustrated in FIG.
5B.
[0061] In this method, the coils 7 do not wound around a core back
6a, and therefore the core back 6a can be used to fix the moving
magnetic field generation section 3.
Conclusion
[0062] Returning to FIG. 1A, the moving magnetic field generation
sections 3 are disposed such that the end surfaces of the cores 6
are parallel to the inner surface of the side walls inclining at
draft angle. Therefore, a difference in thrust in the vertical
direction of the side walls is unlikely to be generated. That is,
the whole of a material along the wall surfaces flows, and
therefore stirring efficiency is high, growth of crystals is
prevented. As illustrated in FIG. 2A, a pair of the moving magnetic
field generation sections 3, 3 generate moving magnetic fields in
the reverse directions from each other so as to generate a vortex
in the molten metal, and therefore stirring efficiency is high.
Second Embodiment
3. Another Embodiment
[0063] Now, FIG. 6 illustrates a manufacturing apparatus according
to another embodiment. The manufacturing apparatus 10 includes a
base 11 installed on a floor surface of a building such as a
factory, and inclined plates 12, which are provided in the base 11,
and to which the moving magnetic field generation sections 3 are
fixed. The two inclined plates are used as one set, and are
provided with the respective moving magnetic field generation
sections 3. These inclined plates 12, 12 are disposed so as to face
each other. In the base 11, inclination adjusting mechanisms 13
that adjust the inclination of the inclined plates 12 are
provided.
(Base 11, Inclined Plates 12, Inclination Adjusting Mechanisms
13)
[0064] The base 11 includes a base plate 11a installed on the floor
surface, a placing stand 11b that is erected from the vicinity of a
center of the base plate 11a, and allows a die 2 to be placed on an
upper surface thereof, and a pair of supporting sections 11c, 11c
erected from the base with the placing stand 11b therebetween.
[0065] The inclined plates 12 each are a flat plate shape, and
formed of metal such as stainless steel. Each inclined plate is
rockingly pivoted to the vicinity of an upper end of the supporting
section 11c. A shaft of the rocking is a shaft 12a parallel to a
longitudinal axis of the die 2.
[0066] The inclination adjusting mechanisms 13 each include a screw
mechanism 13a. The screw mechanism 13a is disposed below the shaft
12a. In the screw mechanism 13a, a male screw member is screwed in
the female screw member provided in the supporting section 11c
toward the inclined plate 12, so that a lower part of the inclined
plate 12 is pressed, and the inclined plate 12 is rotated about the
shaft 12a as a rotation center.
[0067] In each inclination adjusting mechanism 13, the moving
magnetic field generation section 3 can be disposed such that an
end surface of the core 6 is parallel to an inner surface 5c of the
side wall by changing the inclination of the inclined plate 12.
Therefore, a difference in thrust is unlikely to be generated in
molten metal in the vertical direction of the side wall. The whole
of the material along the wall surfaces flows, and therefore growth
of metal crystals is prevented, and minute metal molded body is
formed.
[0068] In the manufacturing apparatus 10, moving mechanisms 14 that
allow the supporting sections 11c to be freely movable to the bases
plate 11a may be provided. As the moving mechanism 14 (two-dot
chain lines), conventionally known mechanisms such as slide
mechanisms can be used. By use of the moving mechanisms 14, the
inclined plates 12 are brought closer to or away from the side wall
5, that is, are moved with parallel translation to adjust the
gaps.
[0069] As the manufacturing apparatus 10, both the moving
mechanisms 14 and the inclination adjusting mechanisms 13 are
preferably provided.
(Transposing Mechanism of Laminar Flow)
[0070] For example, as illustrated in FIG. 7A and FIG. 7B, a moving
magnetic field generation section 15 that generates a inclined
vertical flow P can be used. In this case, the inclined vertical
flow is generated in molten metal, and molten metal in upper and
lower layers in a die is transposed. Consequently, residual gas
venting is facilitated, more efficient stirring is attained, and
therefore it is possible to make crystal grains fine.
[0071] More specifically, in the moving magnetic field generation
section 15, slits 8b obtained by inclining (skewing) two central
slits in the advancing direction from a bottom to a top are formed.
Consequently, coil end portions are the same appearance as a
general coil end, and therefore there is no waste in assembling
appearance.
[0072] As the shape of the bottom of the die 2, a hemispherical
bottom for smoothly reversing a downward flow of axially moving
molten metal 1 to an upward flow is preferably provided (not
illustrated). Reference numeral 8c in FIG. 7B denotes a wedge or
plate for holding the coil 7 in the slot 8.
Third Embodiment
[0073] FIG. 8 illustrates a manufacturing apparatus according to
another embodiment. This embodiment includes a large number of
parts which are the same as the parts described in the above
embodiments, and therefore the same parts are denoted by the same
reference numerals, and description thereof will be omitted.
[0074] A manufacturing apparatus 16 illustrated in FIG. 8 includes
a die 17 having an inverted T-shape in plan view, and a plurality
of pairs of the moving magnetic field generation sections 3
disposed along a wall surface of the die so as to sandwich the die
17.
[0075] Near a root of the T shape of the die 17, curved side walls
17a having curved inner surfaces are provided. In this embodiment,
moving magnetic field generation sections 18 having curved surfaces
parallel to the curved inner surfaces are provided so as to face
the curved inner surfaces of the curved side walls 17a in order to
maintain uniform gaps. Additional magnetic body members 19 are
provided on end surfaces of cores 7 of the moving magnetic field
generation sections 18. End surfaces 19a of the additional magnetic
body members are curved surfaces along the curved side walls 17a of
the die 17. The additional magnetic body members 19 are mounted on
teeth 9 of cores 6 that generate magnetic fields, are designed so
as to be parallel to the inner surfaces of the curved side walls
17a by magnetically extending the teeth 9.
[0076] A moving magnetic generation section of this embodiment
includes twelve moving magnetic field generation sections 3
provided on liner parts, and the two moving magnetic field
generation sections 18 provided at corners. Thus, the moving
magnetic field generation section is divided, and two kinds of the
moving magnetic field generation sections are further combined and
disposed, so that it is possible to correspond to various shaped of
dies. Consequently, it is possible to uniformly stir molten metal
in various shaped dies (refer to arrows in the figure).
[0077] Now, details of the curved moving magnetic field generation
sections 18 will be described with reference to FIG. 9A and FIG.
9B. FIG. 9A illustrates a state where an additional magnetic body
member 19 is detached from the moving magnetic field generation
section 18 of FIG. 8. Insertion ports 18a are formed in distal end
surfaces (surfaces facing the side wall of the die) of the teeth 9
of the moving magnetic field generation section in FIG. 9A. On the
other hand, as illustrated in FIG. 9B, insertion sections 19b that
slide to be inserted into the insertion ports 18a are formed in
proximal end surfaces of the additional magnetic body member 19.
The additional magnetic body member 19 is freely engaged and
disengaged by sliding. Therefore, an additional magnetic body
member in accordance with a curved shape of a die only needs to be
prepared with respect to the single moving magnetic field
generation sections 18 as a base, and therefore this configuration
is economical.
[0078] FIG. 9C illustrates an additional magnetic body member 20
having a recessed curved surface.
[0079] The additional magnetic body member may be curved in the
height direction (not illustrated).
4. Modification
[0080] As a material of the die 2, metal having heat resistance
withstanding of the high temperature of molten metal, and having
magnetic permeability (for example, stainless steel), ceramics, and
the like can be used.
[0081] The die may have a shape such as an arc shape or a forked
shape in plan view.
[0082] The upper part of the die 2 is opened in this embodiment,
but may be closed by an openable lid. In this case, the lid is
opened, and molten metal is put into the die or extracted a metal
molded body.
* * * * *