U.S. patent application number 14/251064 was filed with the patent office on 2015-10-15 for tilting gravity casting apparatus and tilting gravity casting method.
This patent application is currently assigned to RYOBI LTD.. The applicant listed for this patent is RYOBI LTD.. Invention is credited to Hitoshi Ishida, Yousuke Kado, Mitsumasa Sato.
Application Number | 20150290708 14/251064 |
Document ID | / |
Family ID | 54264309 |
Filed Date | 2015-10-15 |
United States Patent
Application |
20150290708 |
Kind Code |
A1 |
Kado; Yousuke ; et
al. |
October 15, 2015 |
TILTING GRAVITY CASTING APPARATUS AND TILTING GRAVITY CASTING
METHOD
Abstract
In a tilting gravity casting apparatus, a die includes a ladle
that stores a molten metal and the molten metal is poured through a
runner into a cavity of the die when the die is tilted. The
apparatus includes a block member for blocking the runner, a
pressing pin for pressing the molten metal in the cavity, a
controller that controls operation of driving the block member and
the pressing pin, and a first molten metal sensing sensor disposed
in the runner. The controller is configured to start driving the
block member and the pressing pin based on a detection signal
outputted from the first molten metal sensing sensor.
Inventors: |
Kado; Yousuke; (Fuchu-shi,
JP) ; Ishida; Hitoshi; (Fuchu-shi, JP) ; Sato;
Mitsumasa; (Fuchu-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
RYOBI LTD. |
Fuchu-shi |
|
JP |
|
|
Assignee: |
RYOBI LTD.
Fuchu-shi
JP
|
Family ID: |
54264309 |
Appl. No.: |
14/251064 |
Filed: |
April 11, 2014 |
Current U.S.
Class: |
164/457 ;
164/155.1 |
Current CPC
Class: |
B22C 9/082 20130101;
B22D 37/00 20130101; B22D 23/006 20130101; B22D 41/04 20130101 |
International
Class: |
B22D 37/00 20060101
B22D037/00; B22D 46/00 20060101 B22D046/00; B22D 41/04 20060101
B22D041/04; B22C 9/00 20060101 B22C009/00 |
Claims
1. A tilting gravity casting apparatus in which a die includes a
ladle that stores a molten metal and the molten metal is poured
through a runner into a cavity of the die when the die is tilted,
the apparatus comprising: a block member for blocking the runner; a
pressing pin for pressing the molten metal in the cavity; a
controller that controls operation of driving the block member and
the pressing pin; and a first molten metal sensing sensor disposed
in the runner, wherein the controller starts driving the block
member and the pressing pin based on a detection signal outputted
from the first molten metal sensing sensor.
2. The tilting gravity casting apparatus according to claim 1,
wherein the die has an upper die and a lower die, the runner has a
molten metal storage recessed in the upper die, and the first
molten metal sensing sensor is disposed above the molten metal
storage.
3. The tilting gravity casting apparatus according to claim 1,
wherein a second molten metal sensing sensor is disposed in the
vicinity of an inlet of the runner, and the controller measures the
time elapsed from the time when a detection signal outputted from
the second molten metal sensing sensor is transmitted to the
controller to the time when the detection signal outputted from the
first molten metal sensing sensor is transmitted to the
controller.
4. A tilting gravity casting method comprising performing casting
by using the tilting gravity casting apparatus according to claim
1.
5. The tilting gravity casting apparatus according to claim 2,
wherein a second molten metal sensing sensor is disposed in the
vicinity of an inlet of the runner, and the controller measures the
time elapsed from the time when a detection signal outputted from
the second molten metal sensing sensor is transmitted to the
controller to the time when the detection signal outputted from the
first molten metal sensing sensor is transmitted to the
controller.
6. A tilting gravity casting method comprising performing casting
by using the tilting gravity casting apparatus according to claim
5.
7. A tilting gravity casting method comprising performing casting
by using the tilting gravity casting apparatus according to claim
3.
8. A tilting gravity casting method comprising performing casting
by using the tilting gravity casting apparatus according to claim
4.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a tilting gravity casting
apparatus and a tilting gravity casting method using the
apparatus.
[0003] 2. Background Art
[0004] A tilting gravity casting apparatus in which a die includes
a molten metal basin (ladle) that stores a molten metal and the
molten metal is poured into a cavity in the die through a runner
when the die is tilted is well known as described, for example, in
Patent Literature 1 mentioned below.
[0005] Such a tilting gravity casting apparatus of related art has
the following problems when producing a cast product having a
complicated shape, such as a knuckle for an automobile, which is a
part that connects a bearing supporting a wheel to a suspension:
The cavity in the die cannot be filled with molten metal all the
way down to the end of the cavity; and a cast product cannot be
sufficiently free of shrinkage cavities and other casting
defects.
PRIOR ART LITERATURE
Patent Literature
[0006] Patent Literature 1: Japanese Patent Application Laid-Open
No. 9-235828
[0007] The present invention therefore has been made in view of the
problems with related art described above. An object of the present
invention is to provide a tilting gravity casting apparatus and a
tilting gravity casting method using the apparatus that are
excellent in filling a die cavity with a molten metal and are
capable of forming a cast product sufficiently free of casting
defects, and another object of the present invention is to
provide.
SUMMARY OF THE INVENTION
[0008] The present invention has been made to achieve the object
described above. A tilting gravity casting apparatus according to
the present invention is a tilting gravity casting apparatus 1 in
which a die 2 includes a ladle 7, which stores a molten metal M,
and the molten metal M is poured through a runner 5 into a cavity 6
of the die 2 when the die 2 is tilted, the apparatus including a
block member 18 for blocking the runner 5, a pressing pin 23 for
pressing the molten metal M in the cavity 6, a controller that
controls operation of driving the block member 18 and the pressing
pin 23, and a first molten metal sensing sensor 24 disposed in the
runner 5, and the controller starts driving the block member 18 and
the pressing pin 23 based on a detection signal outputted from the
first molten metal sensing sensor 24.
[0009] It is preferable in the tilting gravity casting apparatus
that the die 2 have an upper die 4 and a lower die 3, that the
runner 5 have a molten metal storage 5C recessed in the upper die
4, and that the first molten metal sensing sensor 24 be disposed
above the molten metal storage 5C.
[0010] It is further preferable in the tilting gravity casting
apparatus that a second molten metal sensing sensor 26 be disposed
in the vicinity of an inlet 5A of the runner 5, and that the
controller measure the time elapsed from the time when a detection
signal outputted from the second molten metal sensing sensor 26 is
transmitted to the controller to the time when the detection signal
outputted from the first molten metal sensing sensor 24 is
transmitted to the controller.
[0011] A tilting gravity casting method according to the present
invention includes performing casting by using the tilting gravity
casting apparatus 1.
[0012] According to the tilting gravity casting apparatus and the
tilting gravity casting method of the present invention, the cavity
of the die can be filled with the molten metal all the way down to
the end of the cavity, and a cast product can be sufficiently free
of casting defects.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a cross-sectional view of a tilting gravity
casting apparatus according to an embodiment of the invention;
[0014] FIG. 2 is a perspective view of a block member;
[0015] FIG. 3 is a view describing a state in which a die is tilted
by 45.degree. in a die tilt step;
[0016] FIG. 4 is a view describing a state in which a molten metal
storage in a runner is filled with molten metal;
[0017] FIG. 5 is a view describing a state in which a pressing pin
presses the molten metal after the runner is blocked with a block
member; and
[0018] FIG. 6 is a view describing a state in which the die tilt
step is completed.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0019] A tilting gravity casting apparatus according to an
embodiment of the present invention will be described with
reference to the drawings. A tilting gravity casting apparatus 1
includes a die 2 formed of a lower fixed die 3 and an upper movable
die 4, and the fixed die 3 and the movable die 4 define a runner 5
and a cavity 6, as shown in FIG. 1. In the present embodiment, a
groove formed in a movable die partition surface 4A and a fixed die
partition surface 3A define the runner 5. A ladle 7 is fixed to the
fixed die 3 and stores a molten metal M, such as an aluminum
alloy.
[0020] The fixed die 3 is fixed to an upper surface 8a of a base 8.
The lower end of each guide shaft 9 is fixed to the base 8, and the
upper end of each of the guide shafts 9 is fixed to a top plate 10.
A hydraulic cylinder 11 is fixed to an upper surface 10a of the top
plate 10, and the leading end of a cylinder rod 12, which passes
through the top plate 10, is connected to a movable plate 13, which
is disposed below the top plate 10. When the hydraulic cylinder 11
is driven, the movable plate 13 is guided along the guide shafts 9
and movable between the base 8 and the top plate 10 upward and
downward in FIG. 1. Connection members 14 are provided below the
movable plate 13 and connect the movable plate 13 to the movable
die 4. The movable die 4 is therefore movable along with the
movable plate 13 between the base 8 and the top plate 10 upward and
downward in FIG. 1.
[0021] The tilting gravity casting apparatus 1 includes a tilting
mechanism (not shown). The tilting mechanism has a well-known
configuration. The tilting mechanism includes a tilting shaft
provided in the base 8 and extending in the direction perpendicular
to the plane of view of FIG. 1, a support arm (not shown) that
supports the tilting shaft, and a tilting motion drive device
attached to the support arm. The tilting motion drive device is
controlled by a controller that will be described later and is
capable of tilting the base 8 and the die 2 by about 90 degrees at
a predetermined speed from the horizontal state shown in FIG. 1 in
the direction indicated by the arrow a.
[0022] A hydraulic cylinder 15, which serves as a block member
drive device, is fixed to an upper surface 4a of the movable die 4.
A cylinder rod 16 of the hydraulic cylinder 15 is connected to a
block member 18 via a coupling 17 in a hole 4b formed in the
movable die 4. The block member 18 has a circular-column-shaped
head 18a, which is accommodated in the coupling 17, and a
square-column-shaped shaft 18b, as shown in FIG. 2. The block
member 18 is disposed in a position slightly shifted from the
center between an inlet 5A and an outlet 5B of the runner 5 toward
the outlet 5B. When the controller that will be described later
drives the hydraulic cylinder 15, the leading end surface of the
shaft 18b enters and blocks the runner 5.
[0023] A hydraulic cylinder 20, which serves as a pressing pin
drive device, is fixed to a lower surface 8b of the base 8 via
support rods 19. A cylinder rod 21 of the hydraulic cylinder 20 is
connected to a pressing pin 23 via a coupling 22. The pressing pin
23 passes through the base 8 and is disposed in a hole 3a formed in
the fixed die 3. When the controller that will be described later
drives the hydraulic cylinder 20, the leading end of the pressing
pin 23 enters the cavity 6, which will be described later, and the
pressing pin 23 presses the molten metal M in the cavity 6.
[0024] An extruding pin (not shown) is provided in the die 2. After
the movable die 4 is parted from the fixed die 3, the extruding pin
can extrude the molten metal M having solidified in the runner 5
and the cavity 6 out of the die 2. Further, an air gap around the
extruding pin forms a gas discharge path (not shown) that passes
through the die 2, and a degassing device (not shown) is connected
to the gas discharge path. The degassing device can suck and
discharge gases in the cavity 6 in a die tilt step that will be
described later and can supply the gas discharge path with air in a
parting agent application step that will be described later.
[0025] The runner 5, through which the molten metal M moves, has a
substantially rectangular cross-sectional shape when taken along
the direction perpendicular to the plane of view of FIG. 1, and is
defined by: a lateral-U-shaped groove formed in the movable die
partition surface 4A; and the fixed die partition surface 3A, in
such a way that the runner 5 extends rightward and leftward in FIG.
1. The runner 5 has a molten metal storage 5C in the vicinity of
the outlet 5B. The molten metal storage 5C is a hole further
recessed upward in FIG. 1 from the bottom surface of the
lateral-U-shaped groove formed in the movable die partition surface
4A, which defines the runner 5, and a first molten metal sensing
sensor 24 is disposed above the hole. Specifically, the first
molten metal sensing sensor 24 is so disposed in the movable die 4
that the sensor 24 is exposed through the bottom of the hole. The
first molten metal sensing sensor 24 is an electrical detection
sensor having a well-known configuration and outputs a detection
signal when the molten metal M which flowed into the molten metal
storage 5C and rose to the bottom of the hole, has come into
contact with the first molten metal sensing sensor 24. The
detection signal is transmitted to the controller that will be
described later via a wiring line 25.
[0026] A second molten metal sensing sensor 26 is disposed in the
vicinity of the inlet 5A of the runner 5. Specifically, the second
molten metal sensing sensor 26 is so disposed in the fixed die 3
that the sensor 26 is exposed through a fixed die partition surface
3A, which defines the runner 5. The second molten metal sensing
sensor 26 is an electrical detection sensor having a well-known
configuration and outputs a detection signal when the molten metal
M which flowed through the inlet 5A of the runner 5 has come into
contact with the second molten metal sensing sensor 26. The
detection signal is transmitted to the controller that will be
described later via a wiring line 27.
[0027] The tilting gravity casting apparatus 1 includes the
controller (not shown) that controls the tilting motion drive
device, the block member drive device, the pressing pin drive
device, and other drive devices. The controller emits a signal that
starts driving the hydraulic cylinder 15 at the same time as the
detection signal outputted from the first molten metal sensing
sensor 24 is transmitted to the controller, so as to start blocking
the runner 5 by driving the block member 18. The controller further
emits a signal that starts driving the hydraulic cylinder 20 at
predetermined timing after the controller emits the signal that
starts driving the hydraulic cylinder 15, so as to start pressing
the molten metal M in the cavity 6 by driving the pressing pin
23.
[0028] The controller further measures the time elapsed from the
time when the detection signal outputted from the second molten
metal sensing sensor 26 is transmitted to the controller to the
time when the detection signal outputted from the first molten
metal sensing sensor 24 is transmitted to the controller. When the
measured time is shorter than a predetermined value, the controller
does not emit the signals that start driving the hydraulic
cylinders 15 and 20 but notifies an operator of failure in filling
the cavity with the molten metal or any other type of abnormality
in the form of a buzzer or any other notification device.
[0029] A description will next be made of a tilting gravity casting
method using the tilting gravity casting apparatus 1. In the
tilting gravity casting method, a molten metal preparation step of
storing the molten metal M in the ladle 7 is first carried out to
achieve the state shown in FIG. 1.
[0030] A die tilt step is then initiated, in which the die 2 is
tilted from the state shown in FIG. 1 by about 90.degree. in the
direction indicated by the arrow a so that the molten metal M in
the ladle 7 is poured through the runner 5 into the cavity 6. The
die 2 is tilted by the tilting mechanism (not shown) at a
predetermined speed. With the die 2 being tilted in the die tilt
step, the molten metal M in the ladle 7 is poured through the
runner 5 into the cavity 6. Specifically, when the molten metal M
flows into the inlet 5A of the runner 5 and comes into contact with
the second molten metal sensing sensor 26, the second molten metal
sensing sensor 26 emits the detection signal, which is transmitted
to the controller via the wiring line 26.
[0031] When the die 2 is tilted by about 45.degree. and the cavity
6 is substantially filled with the molten metal M, the molten metal
M rises through the molten metal storage 5C, which is located in
the vicinity of the outlet of the runner 5, as shown in FIG. 3.
When the molten metal storage 5C is filled with the molten metal M
and the molten metal M comes into contact with the first molten
metal sensing sensor 24 as shown in FIG. 4, the first molten metal
sensing sensor 24 outputs the detection signal. When the detection
signal is transmitted to the controller via the wiring line 25, the
controller emits a signal that starts driving the hydraulic
cylinder 15 to initiate a runner block step of blocking the runner
5 by causing the leading end surface of the block member 18 to abut
(or approach) the fixed die partition surface 3A.
[0032] After the block member 18 blocks the runner 5 in the runner
block step, the controller emits a signal that drives the hydraulic
cylinder 20 to initiate a press step of causing the pressing pin 23
to enter the cavity 6 (see FIG. 5). At an appropriate timing after
the cavity 6 is filled with the molten metal M and the runner 5 is
blocked, the press step is initiated to cause the pressing pin 23
to press the molten metal M in the cavity 6. The press step allows
a surface layer in, for example, the end of the cavity 6 that tends
to separate from the die 2 due to solidification shrinkage to be
pressed against the die 2. Further, the molten metal M
corresponding to the loss due to the solidification shrinkage can
be forced inside by pressure in the press step, whereby a cast
product C (see FIG. 6) can be sufficiently free of shrinkage
cavities and other casting defects.
[0033] The controller measures the time elapsed from the time when
the detection signal outputted from the second molten metal sensing
sensor 26 is transmitted to the controller to the time when the
detection signal outputted from the first molten metal sensing
sensor 24 is transmitted to the controller. When the measured time
is shorter than a predetermined value, the controller does not
initiate the runner block step or the press step but notifies the
operator of failure in filling the cavity with the molten metal or
any other type of abnormality in the form of a buzzer or any other
notification device.
[0034] The tilting operation continues after the press step is
completed but is terminated when the state shown in FIG. 6, which
is the state after the state shown in FIG. 1 is tilted by about
90.degree., is achieved, and the die tilt step is completed.
[0035] When a die cooling device (not shown) causes the molten
metal in the cavity 6 to solidify, the hydraulic cylinder 20 is
driven to retract the pressing pin 23 leftward in FIG. 6, and then
a die open step is carried out. In the die open step, the hydraulic
cylinder 11 is driven to move the movable plate 13 along with the
movable die 4 rightward in FIG. 6 so that the movable die 4 is
parted from the fixed die 3. The following steps are then
sequentially carried out: a cast product removal step of removing
the cast product from the die 2 by using the extruding pin (not
shown) provided in the die 2; a parting agent application step of
applying a parting agent onto the runner 5 and the cavity 6; and a
die clamping step of driving the hydraulic cylinder 11 to move the
movable plate 13 along with the movable die 4 leftward in FIG. 6 so
that the movable die 4 abuts the fixed die 3. Finally, the tilt
mechanism is used to restore the state of the die 2 shown in FIG.
1. The tilting gravity casting method has been described above.
[0036] According to the tilting gravity casting apparatus 1 and the
tilting gravity casting method of the present embodiment, the
detection signal outputted from the first molten metal sensing
sensor 24 disposed in the runner 5 allows the controller to
recognize the time when the cavity 6 is filled with the molten
metal M, and the controller initiates the runner block step using
the block member 18 and the press step using the pressing pin 23
based on the detection signal, whereby the runner block step and
the press step can be carried out at an appropriate timing.
Therefore, the cavity 6 of the die 2 can be filled with the molten
metal M all the way down to the end of the cavity 6, and the cast
product C can be sufficiently free of casting defects.
[0037] Further, since the controller measures the time elapsed from
the time when the detection signal outputted from the second molten
metal sensing sensor 26 is transmitted to the controller to the
time when the detection signal outputted from the first molten
metal sensing sensor 24 is transmitted to the controller, failure
in filling the cavity with the molten metal or any other type of
abnormality can be detected and the speed at which the tilt motion
drive device performs the tilting operation can be changed based on
the measured time.
[0038] The tilting gravity casting apparatus and the tilting
gravity casting method according to the present invention are not
limited to those described in the above embodiment, and a variety
of changes and modifications can be made thereto to the extent that
they fall within the scope of the claims. For example, in the
embodiment described above, the pressing pin 23 is disposed on the
side where the fixed die 3 is present, but the pressing pin 23 may
instead be disposed on the side where the movable die 4 is
present.
[0039] Further, in the embodiment described above, the press step
is completed before the die tilt step is completed, but the
initiated press step may be allowed to continue after the die tilt
step is completed.
[0040] Further, in the embodiment described above, the press step
is completed before the die tilt step is completed, but after the
die tilt step is completed, the locked pressing pin may be unlocked
and the press step may be resumed.
DESCRIPTION OF THE REFERENCE NUMBERS
[0041] 1 Tilting gravity casting apparatus [0042] 2 Die [0043] 3
Fixed die [0044] 3A Fixed die partition surface [0045] 4 Movable
die [0046] 4A Movable die partition surface [0047] 4a Upper surface
[0048] 5 Pouring gate [0049] 5A Inlet [0050] 5B Outlet [0051] 5C
Molten metal storage [0052] 6 Cavity [0053] 7 Ladle [0054] 8 Base
[0055] 8a Upper surface [0056] 8b Lower surface [0057] 9 Guide
shaft [0058] 10 Top plate [0059] 10a Upper surface [0060] 11
Hydraulic cylinder [0061] 12 Cylinder rod [0062] 13 Movable plate
[0063] 14 Connection shaft [0064] 15 Hydraulic cylinder [0065] 16
Cylinder rod [0066] 17 Coupling [0067] 18 Block member [0068] 18a
Head [0069] 18b Shaft [0070] 19 Support rod [0071] 20 Hydraulic
cylinder [0072] 21 Cylinder rod [0073] 22 Coupling [0074] 23
Pressing pin [0075] 24 First molten metal sensing sensor [0076] 25
Wiring line [0077] 26 Second molten metal sensing sensor [0078] 27
Wiring line [0079] M Molten metal [0080] C Cast product
* * * * *