DESCRIPTION
TITLE OF INVENTION: PRESS MOLDING METHOD FOR CUPSHAPED
MEMBER
TECHNICAL FIELD
[0001] The present invention relates to a press
molding method for a cup-shaped member.
BACKGROUND ART
[0002] A cup-shaped member is a member of a shape
having a bottom portion and a vertical wall portion
rising continuously from the bottom portion, and is
broadly used as a machine part for application to a
container, a rotation member, and so on. Thicknesses
of the bottom portion and the vertical wall portion
of such a cup-shaped member are not constant
depending on an application for usage, and there is a
case where the thickness of a specific region is
partially changed. Many methods for changing the
thickness of the vertical wall portion are presented
as disclosed in Patent Literatures 1 to 8 and Non
Patent Literature 1, for example.
[0003] On the other hand, with regard to a method
for partially changing a thickness of a bottom
portion, for example, though Patent Literature 9
discloses a molding method for a cup-shaped member
having a bottom portion with a thickness difference
from a plate-shaped crude material, there are fewer
~xamples of disclosure, compared with the
aforementioned method for changing the thickness of
the vertical wall portion.
- 1 -
.·"
CITATION LIST
PATENT LITERATURE
[0004] Patent Literature 1: Japanese Laid-open
Patent Publication No. 61-140327
Patent Literature 2: Japanese Laid-open Patent
Publication No. 07-155888
Patent Literature 3: Japanese Laid-open Patent
Publication No. 07-256377
Patent Literature 4: Japanese Laid-open Patent
Publication No. 2000-24745
Patent Literature 5: Japanese Laid-open Patent
Publication No. 2000-288642
Patent Literature 6: Japanese Laid-open Patent
Publication No. 2000-317565
Patent Literature 7: Japanese Laid-open Patent
Publication No. 2001-47175
Patent Literature 8: Japanese Laid-open Patent
Publication No. 2009-248092
Patent Literature 9: Japanese Laid-open Patent
Publication No. 2010-172916
NON PATENT LITERATURE
[0005] Non Patent Literature 1: "Automotive
Eng~neering•, Society of Automotive Engineers of
Japan, 1996, Vol. 50, No. 12, p 31 'to 37
SUMMARY OF INVENTION
TECHNICAL PROBLEM
[0006] Patent Literature 9 discloses a molding
method for molding a cup-shaped member having a
bottom portion with a thickness difference from a
- 2 -
plate-shaped crude material by using divided molds.
However, since this molding method has five processes,
numerous molds are necessary, and there are concerns
of increase of a mold cost and reduction of
productivity arising from exchange work of molds.
SOLUTION TO PROBLEM
[0007] A pre~s molding method for a cup-shaped
member of the present invention in which a bottom
portion thickness of the cup-shaped member is
partially increased when a flat plate-shaped crude
material is molded into the cup-shaped member, while
using a first mold having a column-shaped first upper
tool, a cylinder-shaped second upper tool disposed
along an outer periphery of the first upper tool and
formed of an upper tool inclined portion whose tip
surface is inclined in a manner to approach a center
axis as going downward, a cylinder-shaped third upper
tool disposed along an outer periphery of the second
upper tool, and a first lower tool which is a hole
portion to allow entering of the first upper tool,
the second upper tool, and the third upper tool, the
hole portion being formed of a hole portion vertical
walL portion extending along the third upper tool
entering the inside of the hole portion1 a hole
portion inclined portion continuously provided in a
lower end portion of the hole portion vertical wall
portion and inclined in a manner to approach a center
axis as going downward, and a hole portion bottom
surface portion continuously provided in a lower end
- 3 -
portion of the hole portion inclined portion and
extending in a direction orthogonal to the center
axis, the respective center axes thereof being
disposed coaxially to one another, the press molding
method for the cup-shaped member has: a first process
of pushing the crude material into the hole portion
of the first lower tool to bend the crude material by
relatively moving the first upper tool and the second
upper tool in a direction to approach the first lower
tool; and a second process of making a part of the
crude material flow into a space formed between the
upper tool inclined portion and the hole portion
inclined portion to thicken that part by relatively
moving the third upper tool in the direction to
approach the first lower tool and pushing an upper
end portion of the crude material, and the press
molding method for the cup-shaped member has a third
process of press-molding the part thickened in the
second process into a shape extendingly existing in a
direction almost orthogonal to a center axis of the
cup-shaped member by using a second mold different
from the first mold.
ADVANTAGEOUS EFFECTS OF INVENTION·
(0"008] According to the invention of the present
application, it becomes possible to simplify a press
molding method for a cup-shaped member having a
bottom portion with a thickness difference.
BRIEF DESCRIPTION OF DRAWINGS
[0009] [Fig. 1] is-a schematic diagram of a mold
- 4 -
used in a rough molding process;
[Fig. 2] is a schematic diagram of a mold used in
a finish molding process;
[Fig. 3A] is an action explanatory diagram of the
mold used in the rough molding process {waiting
status);
[Fig. 38] is an action explanatory diagram of the
mold used in the rough molding process {compressing
process of first process);
[Fig. 3C] is an action explanatory diagram of the
mold used in the rough molding process {bending
process of first process);
[Fig. 3D] is an action explanatory diagram of the
mold used in the rough molding proc~ss {second
process);
[Fig. 4A] is an action explanatory diagram of the
mold used in the finish molding process {waiting
status);
[Fig. 48] is an action explanatory diagram of the
mold used in the finish molding process {third
process);
[Fig. 4C] is an action explanatory diagram of the
·' mold used in the f.inish molding pro.cess {third
process);
[Fig. SA] is a schematic diagram of a mold used
in a second embodiment;
[Fig. 58] is an action explanatory diagram of the
mold used in the second embodiment {thickening
process);
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il.V I
[Fig. 6A] is a schematic diagram of a mold used
in a third embodiment ( (n-l)th thickening
processing);
[Fig. 68] is a schematic diagram of the mold used
in the third embodiment (nth thickening processing);
[Fig. 7] is an ~ction explanatory diagram of a
mold used in a rough molding process of a fifth
embodiment;
[Fig. 8A] is an action explanatory diagram of a
mold used as an example of a comparative example
(before molding) ; and
[Fig. 88] is an action explanatory diagram of the
mold used as the example of the comparative example
(after molding).
DESCRIPTION OF EMBODIMENTS
[0010] First, a comparative example will be
explained. Fig. 8A and Fig. 88 are action
explanatory diagrams of a mold of the comparative
example. Fig. 8A shows a state before molding and
Fig. 88 shows a state after molding. As shown in Fig.
8A, the mold of the comparative example has a first
upper tool 37, a second upper tool 38, a third upper
tool 39, and a lower tool 40.
As a molding method for a cup-shaped member in
which a thickness (bottom portion thickness) of a
bottom portion is partially changed from a tlat
plate-shaped crude material, following is a method
with fewer processes and simplicity. First, a flat
plate-shaped·crude material 1 is provided in an upper
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,. ,.
portion of the lower tool 40. Next, as shown in Fig.
BB, by lowering the first upper tool 37, the second
upper tool 38, and the third upper tool 39, a cupshaped
member is molded in a hole portion 40a of the
lower tool 40. On this occasion, by pushing a
vertical wall upper end portion by the third upper
tool 39, a material can be made to flow into a
portion where a thickness of the bottom portion is to
be changed. As described above, the material is
filled in a space formed between the second upper
tool 38 and the hole portion 40a of the lower tool 40,
and a thickness of a predetermined bottom portion is
partially changed. However, in this case, as shown
in Fig. BB, since a connection portion P between a
vertical wall lower end portion and the bottom
portion has an almost right-angle shape, a resistance
becomes large when the material passes through that
portion. In other words, a load necessary for
pushing the vertical wall upper end portion by the
third upper tool 39 to make the material flow in the
portion where the thickness of the bottom portion is
to be changed becomes excessively large, so that
there occurs a case where molding is practically
impossible because of restriction of a load capacity
of a press molding apparatus.
[0011] The present invention, in view of the above
problem; provides a molding method for molding a cupshaped
member in which a thickness of a bottom
portion ~s partially changed from a flat plate-shaped
- 7 -
crude material, the method reducing a press load to a
degree where practically no problem occurs and having
as few processes as possible.
[0012) Embodiments of the present invention for
solving the above-described problem will be described
in detail with reference to the drawings.
(First Embodiment}
A press molding method of the present embodiment
includes a rough molding process and a finish molding
process. The rough molding process has a first
process and a second process described in claim 1.
The finish molding process has a third process
described in claim 1.
Fig. 1 is a schematic cross-sectional view of a
mold for implementing the rough molding process
effectively. The mold (equivalent to a first mold}
used in the rough molding process includes a first
upper tool 2, a second upper tool 3, a third upper
tool 4, and a first lower tool 5. The tools 2 to 5
have center axes coaxial to one another, and are
disposed axially symmetrically to the center axis L1.
The first lower tool 5 has a knockout member 6
axially symmetrical'~'to the center axis LT.
[0013) Further, the tools 2 to 5 and the knockout
member 6 ~are each connected to not-shown drive
mechanisms (for example, motors or hydraulic power
units}, and independently rises/lowers in a center
axis Ll direction as a result that the respective
driv&mechanisms work. A not-shovm controller
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controls rising/lowering actions of the tools 2 to S
and the knockout member 6 by controlling driving of
the respective drive mechanisms. As the controller,
a CPU or an MPU can be used. A press molding
apparatus is constituted by the mold, the drive
mechanism, and the controller.
Note that the knockout member 6 may be of fixed
type, which is unmovable. Further, in other tools
described later, drive mechanisms similar to those of
the first mold are provided.
[0014] The first upper tool 2 is formed in a column
shape. The second upper tool 3 is formed in a
cylinder shape, an inner peripheral surface of which
is disposed along an outer periphery of the first
upper tool 2. A tip surface (lower end surface) of
the second upper tool 3 is formed of an upper tool
inclined portion 3a which is inclined in a manner to
approach the center axis Ll as going downward. The
third upper tool 4 is formed in a cylinder shape and
disposed along an outer periphery of the second upper
tool 3.
[001S] The first lower tool S has a lower tool hole
portion Sa to allow entering of the first upper tool
2, the second upper tool 3, and the third upper tool
4; The lower tool hole portion Sa is formed of a
hole portion vertical wall portion Sb extending along
an outer peripheral surface of the third upper tool 4
entering the lower tool hole portion Sa, a hole
p.ortion inclined portion Sc continuDusly provided in
- 9 -
a lower end portion of the hole portion vertical wall
portion Sb and inclined in a manner to approach the
center axis Ll as going downward, and a hole portion
bottom surface portion Sd continuously provided in a
lower end portion of the hole portion inclined
portion Sc and extending in a direction orthogonal to
the center axis Ll. In a periphery of the center
axis Ll of the hole portion bottom surface portion 5d
is formed a bottom surface hole portion Se extending
in the center axis Ll direction. The knockout member
6 is disposed in an inner side of the bottom surface
hole portion Se. A tip surface (upper end surface)
of the knockout member 6 is disposed in a position to
be almost flat to the hole portion bottom surface
portion Sd. Note that a "hole portion bottom surface
portion" described in claim 1 is formed of the hole
portion bottom surface portion 5d and the tip surface
of the knockout member 6. However, the knockout
member 6 may be constituted integrally with the first
lower tool 5.
[0016] Here, as shown in Fig. 1, when an angle
(acute angle side) made by the hole portion bottom
-surface po-rt·i·on· Sd and the hole portion inclin'e'd
portion Sc is indicated as Al, the angle Al is
preferable to be set to be 20" or more to 60" or less.
A reason to limit the angle Al will be described
later. Further, as shown in Fig. 1, an angle made by
the upper tool inclined portion 3a and a horizontal
~-·surface is preferable to be set ko be almost the same
- 10 -
I
as the angel Al.
[0017) Fig. 2 is a schematic diagram of a mold for
implementing a finish molding process effectively.
The mold (equivalent to a second mold) used for the
finish molding process includes a first finishing
upper tool 7, a second finishing upper tool 8, a
third finishing upper tool 9, and a first finishing
lower tool 10. The tools 7 to 10 have center axes
coaxial to one another, and are disposed axially
symmetrically to the center axis L2. The first
finishing lower tool 10 has a knockout member 11
axially symmetrical to the center axis L2.
[0018) The first finishing upper tool 7 is formed in
a column shape. The second finishing upper tool 8 is
formed in a cylinder shape, an inner peripheral
surface of which is disposed along an outer periphery
of the first finishing upper tool 7. A tip surface
of the second finishing upper tool 8 is formed by a
flat portion Sa extending in a direction orthogonal
to the center axis L2. The third finishing upper
tool 9 is formed in a cylinder shape and disposed
along an outer periphery of the second finishing
upper too.l 8. ·
The second finishing upper tool 8 has a shape of
the aforementioned second upper tool 3 in which the
upper tool inclined portion 3a is omitted.
[0019) The first finishing lower tool 10 has a hole
portion lOa to allow entering of the first finishing
upper tool 7, the second finishing upper tool 8, and
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=
the third finishing upper tool 9. The hole portion
lOa is formed of a hole portion vertical wall portion
lOb extending along an outer peripheral surface of
the third finishing upper tool 9 entering the hole
portion lOa and a hole portion bottom surface portion
lOd continuously provided in a lower end portion of
the hole portion vertical wall portion lOb and
extending in a direction almost orthogonal to the
center axis L2. In a periphery of the center axis L2
of the hole portion bottom surface portion lOd is
formed a bottom surface hole portion 10e extending in
a center axis L2 direction. The knockout member 11
formed to have almost the same dimension as that of
the knockout member 6 of the first lower tool 5 is
disposed in an inner side of the bottom surface hole
portion 10e. A tip surface of the knockout member 11
is disposed in a position to be almost flat to the
hole portion bottom surface portion 10d. The hole
portion vertical wall portion lOb of the hole portion
lOa is formed to have almost the same inner diameter
as that of the hole portion vertical wall portion 5b
of the aforementioned first lower tool 5.
'T-he first finishing lower tool 10 has a shape of
the afdrementioned first lower tool 5 in which the
hole portion inclined portion Sc is omitted.
[0020) Next, a rough molding process ot the present
embodiment will be described with reference to Fig.
3A to Fig. 3D. Fig. 3A to Fig. 30 are action
explanatory-diagrams of bhe mold shown in Fig. 1 used
- 12 -
in the rough rolling process. First, as shown in Fig.
3A, by the not-shown drive mechanisms of the mold,
the first upper tool 2, the second upper tool 3, and
the third upper tool 4 are raised to heights which do
not hinder providing of a crude material 1 in an
upper portion of the first lower tool 5. Next, the
flat plate-shaped crude material 1 having a disk
shape is provided in the upper portion of the first
lov1er tool 5. On this occasion, the knockout member
6 of the second lower tool 5 is provided in a manner
that the tip surface becomes almost flat to the hole
portion bottom surface portion 5d of the first lower
tool 5.
[0021] Next, as shown in Fig. 3B, the first upper
tool 2 is lowered in an arrow direction to push the
crude material 1 into the lower tool hole portion 5a
while bending the crude material 1, so that a bottom
center portion 1a of the crude material 1 is
compressed between the first upper tool 2 and the
first lower tool 5 (equivalent to a compressing
process of the first process). Accordingly, the
crude material 1 is fixed in a state of being
positioned in the lower tool hole portion 5a.
Here, a case where the first upper tool 2 is
lowered is described,. but the method is not limited
to this case and it suffices that the first upper
tool 2 and the first lower tool 5 can be relatively
moved in a direction to approach. For example, as a
modification example, ~t is possible not to lower the
- 13 -
first upper tool 2 but to raise the first lower tool
5. Further, it is possible to raise the first lower
tool 5 while lowering the first upper tool 2.
However, when such modification examples are
implemented, it is necessary to control positions of
the mold to each other in advance so that the bottom
center portion la of the crude material 1 is not
compressed in the mold by other portions of the mold
before the bottom center portion la of the crude
material 1 is compressed by the first upper tool 2
and the first lower tool 5.
[0022] A timing to complete the process shown in Fig.
3B can be judged from a movement position of the tool,
a press load (load value), or the like. For example,
it is possible that the controller stores a movement
stroke amount of the first upper tool 2 from a
standby position of Fig. 3A to reach a completion
position of Fig. 3B in advance, to halt the first
upper tool 2 when the stored movement stroke amount
is reached. Further, it is possible that the
controller stores a press load applied to the mold
when the. completion position of Fig. 3B is reached in
-· advance, to halt the first uppe~·tool 2 when the
·stored press load is reached.
[0023] Next, as shown in Fig. 3C, the second upper
tool 3 separated from the material 1 is lowered in an
arrow direction to a position by which a space
between the upper tool inclined portion 3a and the
hole portion inclined portion 5c of the first lower·
- 14 -
. ,
tool 5 becomes a predetermined interval T. By
lowering the second upper tool 3, the crude material
1 is bent in correspondence with a shape of the upper
tool inclined portion 3a of the second upper tool 3
and press-molded into a shape made up of the bottom
center portion 1a, a bottom outer edge portion 1b,
and a crude material vertical wall portion 1c
(equivalent to a bending process of the first
process). The bottom center portion 1a is a portion
extendingly exists in a direction orthogonal to the
center axis L1 in the crude material 1. The bottom
outer edge portion 1b is a portion positioned in a
region sandwiched by the upper tool inclined portion
3a and the hole portion inclined portion 5c in the
crude material 1. The crude material vertical wall
portion lc is a portion extending in the center axis
Ll direction in the crude material 1.
Here, the predetermined interval T is required to
have been set to be a size capable of thickening the
bottom outer edge portion lb in a later described
second process of Fig. 3D. In other words, the
predetermined interval T is required to have been set
to be larger than a plate thickness of the crude .
material 1 before thickening.
[0024] A timing to complete the process shown in Fig.
3C can be judged by a movement position of the tool,
a press load, or the like. A concrete method thereof
is described above and explanation will be omitted.
[0025] Thereafter, as shown in Fig. 3D, the third
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.=...=..· . =/~ ~ / j/
upper tool 4 is lowered in an arrow direction. By
pushing a cylinder end portion ld being an upper end
portion of the crude material vertical wall portion
lc by the third upper tool 4, the material is made to
flow from the crude material vertical wall portion lc
into between the upper tool inclined portion 3a and
the hole portion inclined portion 5c, to increase a
thickness of the bottom outer edge portion lb
(equivalent to the second process) On this occasion,
the crude material vertical wall portion lc of the
crude material 1 is restrained in a plate thickness
direction (direction orthogonal to the center axis
Ll) of the crude material 1 by the outer peripheral
surface of the second upper tool 3 and the hole
portion vertical wall portion 5c of the first lower
tool 5.
[0026] Here, the outer peripheral surface of the
second upper tool 3 is an end surface of the second
upper tool 3 formed in a direction parallel to the
center axis Ll. The inner peripheral surface of the
first lower tool 5 is an inner periphery side end
surface of the first lower tool 5 formed in the
direction parallel to th~ center axis Ll.
Further, the second upper tool 3 rises/lowers
independently in relation to the first upper-tool 2.
Therefore, the space formed between the upper tool
inclined portion 3a of the second upper tool 3 and
the hole portion inclined portion 5c of the first
lower tool 5 can be altered arbitrarily. By'' altering
- 16 -
~" l
I
the space, the thickness of the bottom outer edge
portion lb of the crude material 1 can be easily
increased/decreased.
[0027] Note that when the angle Al made by the hole
portion bottom surface portion 5d and the hole
portion inclined portion 5c is less than 10°, a press
load at a time of increasing the thickness of the
bottom outer edge portion lb by making the material
flow from the crude material vertical wall portion lc
of the crude material 1 becomes excessively large.
Therefore, as described above, the angle Al is
preferable to be set to be 20° or more.
[0028] Here, a case where the second upper tool 3
and the third upper tool 4 are lowered is described,
but the method is not limited to this case and it
suffices that the second upper tool 3 and the third
upper tool 4, and the first lower tool 5 can be
relatively moved. For example, as a modification
example, the first upper tool 2 and the first lower
tool 5 may be raised. Further, it is possible to
raise the first upper tool 2 and the first lower tool
5 while lowering the second upper tool 3 and the
third-upper tool 4.-
[{)029] A timing to complete the process shown in Fig.
3D can. be judged from a movement position of the tool,
a press load, or the like. A concrete method thereof
is described above and explanation will be omitted.
Thereafter, the first upper tool 2, the second
upper.~ool 3, and the third upper tool 4 are raised,
- 17 -
and the knockout member 6 of the first lower tool 5
is raised, whereby the crude material 1 as an
intermediate member can be detached from the lower
tool hole portion 5a.
[0030] Next, a finish molding process of the present
embodiment will be described with reference to Fig.
4A to Fig. 4C. Fig. 4A to Fig. 4C are action
explanatory diagrams of the mold shown in Fig. 2 used
in the finish molding process.
[0031] First, as shown in Fig. 4A, by not-shown
drive mechanisms of the mold, the first finishing
upper tool 7, the second finishing upper tool 8, and
the third finishing upper tool 9 are raised to
heights which do not hinder providing of the crude
material 1 molded in the rough molding process in the
hole portion lOa of the first finishing lower tool 10.
Next, the crude material 1 is provided in the hole
portion lOa of the first finishing lower tool 10. On
this occasion, the knockout member 11 of the first
finishing lower tool 10 is provided in a manner that
a tip surface is almost the same as the hole portion
bottom surface portion lOd of the first finishing
lower tool 10.
[0032] Next, as shown in Fig. 48, the first
finJshing upper tool 7 is lo11ered in an arrow
direction, to compress the bottom center portion la
of the crude material 1 between the first finishing
upper tool 7 and the first finishing lower tool 10.
Thereby, the cured material 1 is positioned and fixed
- 18 -
in the hole portion lOa.
Here, a case where the first finishing upper tool
7 is lowered is described, but the method is not
limited to this case, and it suffices that the first
finishing upper tool 7 and the first finishing lower
tool 10 can be relatively moved in a direction to
approach. For example, as a modification example, it
is possible not to lower the first finishing upper
tool 7 but to raise the first finishing lower tool 10.
Further, it is possible to raise the first finishing
lower tool 10 while lowering the first finishing
upper tool 7.
[0033] However, when such modification examples are
implemented, it is necessary to control positions of
the mold to each other in advance so that the bottom
center portion la of the crude material 1 is not
compressed in the mold by other portions of the mold
before the bottom center portion la of the crude
material 1 is sandwiched by the first finishing upper
tool 7 and the first finishing lower tool 10.
[0034] Next, as shown in Fig. 4C, the second
finishing upper tool 8 separated from the crude
material l is lowered to a posit~on by which a space
between the fl~t portion Sa and the first finishing
lower tool 10 becomes a predeter~ined space. Here,
the predetermined space is preferable to be a desired
thickness of the bottom outer edge portion lb of the
crude material 1. The bottom outer edge portion lb
is pushed to the hole bottom sur.,face portion lOd by
- 19 -
the flat portion 8a of the second finishing upper
tool 8. Therefore, the bottom outer edge portion lb
is made to exist extendingly in a direction almost
orthogonal to the center axis L2 of the crude
material 1 and constituted as a bottom portion of the
crude material 1 together with the bottom center
portion la.
On this occasion, in a case where the angle Al
made by the hole portion bottom surface portion 5d
and the hole portion inclined portion 5c in the rough
molding process exceeds 60°, in the finish molding
process, when the second finishing upper tool 8 is
lowered, the bottom outer edge portion lb buckles
between the second finishing upper tool 8 and the
first finishing lower tool 10. Therefore, the angle
Al is preferable to be set to be 60° or less.
Next, the third finishing upper tool 9 is lowered.
By pushing the cylinder end portion ld being the
upper end portion of the crude material vertical wall
portion lc by the third finishing upper tool 9, the
crude material 1 can be finished to have a
predetermined shape.
Here-;-· a case where the second finishing ·upper
tool 8 and the third finishing upper tool 9 are
lowered in sequence is described, but the method is
not limited to this case, and the second finishing
upper tool 8 and the third finishing upper tool 9 may
be lowered simultaneously.
[0035] Thereafter, the first· finishing upper tool 7,
- 20 -
the second finishing upper tool 8, and the third
finishing upper tool 9 are raised and the knockout
member 11 of the first finishing lower tool 10 is
raised, whereby it is possible to detach a molded
cup-shaped member from the hole portion lOa. In the
cup-shaped member molded by the finish molding
process, the bottom outer e~ge part lb of the bottom
portion is molded to be thicker than the bottom
center portion la.
[0036) Note that in general a final product shape of
the crude material is determined by a space
(capacity) of the first upper tool 2, the second
upper tool 3, the third upper tool 4, and the first
lower tool 5, the space corresponding to a volume of
the crude material 1. In other words, a final
product shape of the crude material is determined by
a capacity of a room blocked by the first upper tool
2, the second upper tool 3, the third upper tool 4,
and the first lower tool 5.
[0037] Further, in the rough molding process, when a
press load exceeds a load limit of a press molding
apparatus, the controller may interrupt molding at a
time •that the press load reaches a predetermined
limit load value, to proceed to the succeeding finish
molding process.
[0038) (Second Embodiment)
In the first embodiment, soon after the
thickening process (second process) of Fig. 3D is
carried out, it proceeds .to the finish molding
- 21 -
process (third process). In the present embodiment,
one thickening processing is carried out between the
second process and the third process. Fig. SA is a
schematic cross-sectional view of a mold (equivalent
to a third mold) used for the thickening processing.
Note that explanation of a configuration similar to
that of the first embodiment will be properly omitted.
The mold used for the thickening processing
includes a fourth upper tool 12, a fifth upper tool
13, a sixth upper tool 14, and a second lower tool 15.
The tools 12 to 15 have center axes coaxial to one
another, and are disposed axially symmetrically to
the center axis L3. The second lower tool 15 has a
knockout member 16 axially symmetrical to the center
axis 13.
The fourth upper tool 12 is formed in a column
shape and can be formed in the same shape as that of
the first upper tool 2. The fifth upper tool 13 is
formed in a cylinder shape, and is formed of an upper
tool inclined portion 13a which is inclined in a
manner that a tip surface approaches the center axis
L3 as going downward.
[0~39] Here, when an angle made br'dn upper tool
inclined portion 13a of the fifth upp~r tool 13 and a
horizontal surface is indicated as A2, the angle A2
is smaller than the angle Al (see l!'ig. 1) ot the
second upper tool 3. Note that the angle A2 is
preferable to be 20° or more to 60° or less. A reason
thereof is as- described above and explanation will be
- 22 -
~~-----_ -_--v~ ~/
omitted. The sixth upper tool 14 is formed in a
cylinder shape and is disposed along an outer
periphery of the fifth upper tool 13.
[0040] The second lower tool 15 has a lower tool
hole portion 15a to allow entering of the fourth
upper tool 12, the fifth upper tool 13, and the sixth
upper tool 14. The lower tool hole portion 15a is
formed of a hole portion vertical wall portion 15b
extending along an outer peripheral surface of the
sixth upper tool 14 entering the lower tool hole
portion 15a, a hole portion inclined portion 15c
continuously provided in a lower end portion of the
hole portion vertical wall portion 15b and inclined
in a manner to approach the center axis L3 as going
downward, and a hole portion bottom surface portion
15d continuously provided in a lower end portion of
the hole portion inclined portion 15c and extending
in a direction orthogonal to the center axis L3. In
a periphery of the center axis L3 of the hole portion
bottom surface portion 15d is formed a bottom surface
hole portion 15e extending in a center axis L3
direction. The knockout member 16 is disposed in an
inner side of the bottom surface• hole portion 15e. A-
-tip surface of the knockout member 16 is disposed in
a position to be almost flat to the hole portion
bottom surface portion 15d. An angle (acute angle
side) made by the hole portion bottom surface portion
lSd and the hole portion inclined portion lSc is
almost the same ~s the aforementioned angle A2 made_
- 23 -
by the upper tool inclined portion 13a and the
horizontal surface. Note that a "hole portion bottom
surface portion" described in claim 4 is formed of
the hole portion bottom surface portion 15d and the
tip surface of the knockout member 16. However, the
knockout member 16 may be constituted integrally with
the second lower tool 15.
[0041] In the thickening process of Fig. 3D of the
first embodiment described above, when the press load
exceeds the load limit, the mold is changed to the
mold shown in Fig. 5A and the thickening processing
is further carried out. More specifically, the fifth
upper tool 13 is lowered in a state where the crude
material 1 is compressed by the fourth upper tool 12
and the second lower tool 15. Thereafter, as shown
in Fig. 5B, the sixth upper tool 14 is lowered in an
arrow direction and the cylinder end portion 1d being
an upper end portion of the crude material vertical
wall portion 1c is pushed by the sixth upper tool 14,
whereby the material is made to flow from the crude
material vertical wall portion lc into between the
upper tool inclined portion 13a and the hole portion
inclined portion 15c, to further thicken the bottbfu
outer edge portion lb.
[0042] As described above, by making the angle A2
smaller than the angle Al (see Fig. 1), a target
thickening amount can be satisfied even by a press
molding apparatus with a small press load by carrying
out thickening processings dividedly two times.
- 24 -
. " '
I
[0043] (Third Embodiment)
In the first embodiment, soon after the
thickening process (second process) of Fig. 3D is
carried out, it proceeds to the finish molding
process (third process). In the present embodiment,
there is implemented a re-thickening processing
process in which thickening processings are carried
out a plurality of times between the second process
and the third process. Fig. 6A is a schematic crosssectional
view of a mold used in the re-thickening
processing process of (n-l)th ("n" is an integer
equal to or larger than 2). Fig. 6B is a schematic
cross-sectional view of a mold used in the nth rethickening
processing process. In other words, Fig.
6A and Fig. 6B are cross-sectional views of the molds
used in consecutive arbitrary two processes,
respectively.
[0044] The mold (equivalent to an (n+l)th mold)
shown in Fig. 6A includes a (3xn-2)th upper tool 22,
a (3xn-l)th upper tool 23, a (3xn)th upper tool 24,
and an nth lower tool 25. The tools 22 to 25 have
center axes coaxial to one another, and are disposed
axially symmetrically to ,the center axis Ln-1. The
(3xn-2)th upper tool 22 is formed in a column shape
and can be formed in the same shape as that of the
first upper tool 2. The (3xn-l)th upper tool 23 is
formed in a cylinder shape, and is formed of an upper
tool inclined portion 23a which is inclined in a
manner that a tip surface approaches the center axis
- 25 -
Ln-1 as going downward. The (3xn)th upper tool 24 is
formed in a cylinder shape and disposed along an
outer periphery of the (3xn-1)th upper tool 23. The
nth lower tool 25 has a lower tool hole portion 25a
to allow entering of the (3xn-2)th upper tool 22, the
(3xn-1)th upper tool 23, and the (3xn)th upper tool 24.
The lower tool hole portion 25a is formed of a hole
portion vertical wall portion 25b extending along an
outer peripheral surface of the (3xn)th upper tool 24
entering the lower tool hole portion 25a, a hole
portion inclined portion 25c continuously provided in
a lower end portion of the hole portion vertical wall
portion 25b and inclined in a manner to approach the
center axis Ln-1 as going downward, and a hole
portion bottom surface portion 25d continuously
provided in a lower end portion of the hole portion
inclined portion 25c and extending in a direction
orthogonal to the center axis Ln-1. In a periphery
of the center axis Ln-1 of the hole portion bottom
surface portion 25d is formed a bottom surface hole
portion 25e extending in a center axis Ln-1 direction.
A knockout member 26 is disposed in an inner side of
the bottom surface ~ole portion 25e. A tip surface
of the knockout member 26 is disposed in a position
to be almost flat to the hole portion bottom surface
portion 25d. Note that the knockout member 26 may be
constituted integrally with the nth lower tool 25.
[0045] The mold(equivalent to an (n+2)th mold) shown
in Fig~ 6B incLudes a (3x(n+1)-2)th upper tool 32, a
- 26 -
(3x(n+l)-l)th upper tool 33, a (3x(n+l))th upper tool
34, and an (n+l)th lower tool 35. The tools 32 to 35
have center axes coaxial to one another, and are
disposed axially symmetrically to the center axis Ln.
The (3x(n+l)-2)th upper tool 32 is formed in a column
shape and can be formed in the same shape as that of
the first upper tool 2. The (3x(n+l)-l)th upper tool
33 is formed in a cylinder shape, and is formed of an
upper tool inclined portion 33a which is inclined in
a manner that a tip surface approaches the center
axis Ln as going downward. The (3x(n+l) )th upper
tool 34 is formed in a cylinder shape and disposed
along an outer periphery of the (3x(n+l)-l)th upper
tool 33. The (n+l)th lower tool 35 has a lower tool
hole portion 35a to allow entering of the (3x(n+l)-
2)th upper tool 32, the (3x(n+l)-l)th upper tool 33,
and the (3x(n+l))th upper tool 34. The lower tool
hole portion 35a is formed of a hole portion vertical
wall portion 35b extending along an outer peripheral
surface of the (3x(n+l))th upper tool 34 entering the
lower tool hole portion 35a, a hole portion inclined
portion 35c continuously provided in a lower end
portion of the h0le portion vertical wall portion 35b
and inclined in a manner to approach the center axis
Ln.as going downward, and a hole portion bottom
surface portion 35d continuously provided in a lower
end portion of the hole portion inclined portion 35c
and extending in a direction orthogonal to the center
ax~s Ln. In a periphery of the cent~r axis Ln of the
- 27 -
hole portion bottom surface portion 35d is formed a
bottom surface hole portion 35e extending in a center
axis Ln direction. A knockout member 36 is disposed
in an inner side of the bottom surface hole portion
35e. A tip surface of the knockout member 36 is
disposed in a position to be almost flat to the hole
portion bottom surface portion 35d. Note that the
knockout member 36 may be constituted integrally with
the (n+l)th lo1~er tool 35.
[0046] Here, Fig. 6A and Fig. 6B being compared,
when an angle of the hole portion inclined portion
25c (upper tool inclined portion 23a) in relation to
a horizontal surface is indicated as An-1 and an
angle of the hole portion inclined portion 35c (upper
tool inclined portion 33a) in relation to the
horizontal surface is indicated as An, the angle An
is smaller than the angle An-1. In other words, in
the re-thickening processing process, an angle
becomes smaller in stages, and thus as a result of
carrying out the thickening processings dividedly a
plurality of times, a target thickening amount can be
satisfied even by a press molding apparatus with a
·small press load. Note that it suf£ices that ~he
number of times of the thickening processings car~ied
.out in there-thickening processing process is plural
and the number of times can be determined to a proper
value in view of a size of the mold, a load limit, a
target thickening amount, and so on. Note that the
angle An and the angle An-1 are ~referable to be 20°
- 28 -
or more to 60° or less. A reason thereof is as
described above and explanation will be omitted.
[0047] (Fourth Embodiment)
In the second embodiment and the third embodiment,
cases where the thickening processing or the rethickening
processing is carried out by using
different molds between the second process and the
third process are described. In the present
embodiment, between the second process and the third
process, a thickening processing is carried out by
the same mold as the mold used in the second process.
Here, a case where the mold shown in Fig. 1 of the
first embodiment is used will be described, but
implementation is possible with the case of the
second embodiment and the third embodiment.
[0048] After the rough molding process shown in Fig.
3A to Fig. 3D is ended, the second upper tool 3 is
slightly raised. In other words, a space between the
upper tool inclined portion 3a of the second upper
tool 3 and the hole portion inclined portion Sc of
the first lower tool 5 is set to be larger than the
interval T at a time of the rough molding process (or
the prevLous thickening processing process-or the
previous re-thickening processing process).
Next, the third upper tool 4 is raised, and
thereafter lowered. By pushing the cylinder end
portion ld being the upp~r end portion of the crude
material vertical wall portion lc by the third upper
tool 4, the material is made.to flow from the crude
- 29 -
=4 "'/
~/
material vertical wall portion 1c into between the
upper tool inclined portion 3a and the hole portion
inclined portion Sc, so that the thickness of the
bottom outer edge portion 1b can be increased.
Further, as necessary, it is possible to repeat the
thickening processing process by the second upper
tool 3 and the third upper tool 4 after further
enlarging the space between the upper tool inclined
portion 3a of the second upper tool 3 and the hole
portion inclined portion Sc of the first lower tool 5.
[004 9] Here, a case where the second upper tool 3
and the third upper tool 4 are lowered is described,
but the method is not limited to this case and it
suffices that the second upper tool 3 and the third
upper tool 4, and the first lower tool 5 can be
relatively moved.
[0050] Thereafter, the first upper tool 2, the
second upper tool 3, and the third upper tool 4 are
raised and the knockout member 6 of the first lower
tool 5 is raised, whereby the crude material 1 as the
intermediate member can be detached from the lower
tool hole portion Sa. The detached crude material 1
is pr-ovided in the mold used in the fin-ish molding
process (or the thickening processing process of the
second embodiment or the re-thickening processing
process of the third embodiment).
[0051] As described above, as a result of setting
the space between the upper tool inclined portion 3a
and the hole portdon inclined portion 5c larger than
- 30 -
the previous time by using the same mold, even by a
press molding apparatus with a small press load, a
target thickening amount can be satisfied by carrying
out the thickening processessins dividedly a
plurality of times.
[0052] (Fifth 8mbodiment)
In the rough molding process of the first
embodiment, there is described a case where, first,
the first upper tool 2 is lowered to compress the
bottom center portion la of the crude material 1
between the first upper tool 2 and the first lower
tool 5, and next the second upper tool 3 is lowered.
In the present embodiment, a case where the first
upper tool 2 and the second upper tool 3 are
simultaneously lowered will be described.
[0053] First, as shown in Fig. 3A, the crude
material 1 is provided in the upper portion of the
first lower tool 5. Thereafter, as shown in Fig. 7,
a tip surface of the first upper tool 2 is made to
abut on the bottom center portion la of the crude
material 1 and the knockout member 6 of the second
lower tool 5 is raised, whereby the bottom center
peEtion la of the crude material 1 4s compressed
between the first upper tool 2 and the knockout
member 6. Therefore, the crude material 1 is
positioned between the first upper tool 2 and the
knockout member 6. •
[0054] Next, in a state where the crude material 1
is compressed between.the first upper tool 2 and the
- 31 -
knockout member 6, the first upper tool 2, the second
upper tool 3, and the knockout member 6 are lowered
simultaneously. Therefore, the first upper tool 2
and the second upper tool 3 bend the crude material 1
in correspondence with the shapes of the first upper
tool 2 and the second upper tool 3 while pushing the
crude material 1 into the lower tool hole portion Sa.
Therefore, as shown in Fig. 3D, the crude material 1
is press-molded into a shape made up of the bottom
center portion la, the bottom outer edge portion lb,
and the crude material vertical wall portion lc.
A timing to complete this process can be judged
from a movement position of the tool, a press load,
or the like. Since a concrete method thereof is
described above, explanation will be omitted.
[0055] Here, a case where the first upper tool 2 and
the second upper tool 3 are lowered is described, but
the method is not limited to this case, and it
suffices that the first upper tool 2 and the second
upper tool 3, and the first lower tool 5 can be
relatively moved in a direction to approach.
[0056] As described above, also in a case where the
, .. ,. fir-st upper tool 2· and the second' upper tool 3 are
~owered simultaneously, the rough fuolding process can
be carried out sim~larly to in the first embodiment.
Further, here, a case where the bottom center portion
la of the crude material 1 is compressed between the
first upper tool 2 and the knockout member 6 as a
result of raising the knockout member 6 is described,
- 32 -
but the method is not limited to this case, and it is
possible not to raise the knockout member 6 and to
lower the first upper tool 2 and the second upper
tool 3 simultaneously. In other words, a compressing
process and a bending process described in the first
embodiment may be carried out simultaneously.
[0057] Note that as a method for a controller of a
press-molding apparatus to detect a press load, a
method of using a load sensor provided in the pressmolding
apparatus is general. However, the present
invention is not limited to this case, and, for
example, when a time since the press molding
apparatus starts molding until the load limit of the
aforementioned tool is exceeded or a displacement
amount of the tool is known in advance by an
experiment or simulation, by counting that time or
measuring the displacement amount of the tool, the
controller may terminate molding before the load
limit is exceeded. In other words, the controller is
not necessarily required to directly compare the
press load and the load limit of the press molding
apparatus as a judgment condition of completion of
.mold, and any method can be.~sed as long as molding
can be completed before the load limit of the press
molding apparatus is exceeded.
[0058] Note that as material of the crude material l,
there can be adopted known various material capable
of plastic working, that is, metal such as steel,
aluminum, and copper, or of an alloy thereof.
- 33 -
[0059] Hereinabove, the present invention is
described with various embodiments, but the present
invention is not limited only to those embodiments
and modification or the like is possible within the
scope of the present invention, and the
aforementioned embodiments can be properly combined.
INDUSTRIAL APPLICABILITY
[0060] The present invention can be used to pressmold
a cup-shaped member in which a bottom portion
thickness is partially increased.

CLAIMS
[Claim 1) A press molding method for a cup-shaped
member in which a bottom portion thickness of the
cup-shaped member is partially increased when a flat
plate-shaped crude material is molded into the cupshaped
member,
while using a first mold having a column-shaped
first upper tool, a cylinder-shaped second upper tool
disposed along an outer periphery of the first upper
tool and formed of an upper tool inclined portion
whose tip surface is inclined in a manner to approach
a center axis as going downward, a cylinder-shaped
third upper tool disposed along an outer periphery of
the second upper tool, and a first lower tool which
is a hole portion to allow entering of the first
upper tool, the second upper tool, and the third
upper tool, the hole portion being formed of a hole
portion vertical wall Rortion extending along the
third upper tool entering the inside of the hole
portion, a hole portion inclined portion continuously
provided in a lower end portion of the hole portion
vertical wall portion and inclined in a manner to
approach a center ax~s as going downward, and a hole
bottom surface portion continuously provided in a
lower end portion of the hole portion inclined
portion and extending in a direction orthogonal to
the center axis, the respective center axes thereof
being disposed coaxially to one another, the press
molding method for the cup-shaped member comprising:
- 35 -
a first process of pushing the crude material
into the hole portion of the first lower tool to bend
the crude material by relatively moving the first
upper tool and the second upper tool in a direction
to approach the first lower tool; and
a second process of making a part of the crude
material flow into a space formed between the upper
tool inclined portion and the hole portion inclined
portion to thicken that part by relatively moving the
third upper tool in the direction to approach the
first lower tool and pushing an upper end portion of
the crude material, and the press molding method for
the cup-shaped member comprising
a third process of press-molding the part
thickened in the second process into a shape
extendingly existing in a direction almost orthogonal
to a center axis of the cup-shaped member by using a
second mold different from the first mold.
[Claim 2] The press molding method for the cupshaped
member according to claim 1,
wherein, in the first process, there are carried
out
a compressing' process of compressing the crude '
material by the first upper tool and the hole portion
bottom surface portion by relatively moving the first
upper tool in the direction to approach the first
lower tool and pushing the crude material into the
hole portion of the first lower tool while bending
the crude material, and
- 36 -
a bending process of bending the crude material
further in correspondence with a shape of the second
upper tool by relatively moving the second upper tool
in the direction to approach the first lower tool.
[Claim 3] The press molding method for the cupshaped
member according to claim 1 or 2,
wherein, when an angle made by the hole portion
inclined portion and the hole portion bottom surface
portion is indicated as A,
20° < angle A ,;; 60°
is satisfied.
[Claim 4] The press molding method for the cupshaped
member according to any one of claims 1 to 3,
while using a third mold having a column-shaped
fourth upper tool, a cylinder-shaped fifth upper tool
disposed along an outer periphery of the fourth upper
tool and formed of an upper tool inclined portion
whose tip surface is inclined in a manner to approach
a center axis as going downward, a cylinder-shaped
sixth upper tool disposed along an outer periphery of
the fifth upper tool, and a second lower tool which
is a hole portion to allow entering of the fourth
upper tool, the fifth upper tool, ca.nd the sixth .upper
tool, the hole portion being formed of a hole portion
.vertical wall portion extending along the sixth upper
tool entering the inside of the hole portion, a hole
portion inclined portion continuously provided in a
lower end portion of the hole portion vertical wall
portion and inclined in a manner.to approach a center
- 37 -
~/
axis as going downward, and a hole portion bottom
surface portion continuously provided in a lower end
portion of the hole portion inclined portion and
extendin_g in a direction orthogonal to the center
axis, the respective center axes thereof being
disposed coaxially to one another, and an angle of
inclination of the upper tool inclined portion in the
fifth upper tool being smaller than an angle of
inclination of the upper tool inclined portion in the
second upper tool, comprising
carrying out a thickening process between the
second process and the third process, the thickening
process making a part of the crude material flow into
a space formed between the upper tool inclined
portion and the hole portion inclined portion to
thicken that part by relatively moving the fifth
upper tool in a direction to approach the second
lower tool in a state where the crude material is
compressed by the fourth upper tool and the second
lower tool and thereafter relatively moving the sixth
upper tool in the direction to approach the second
lower tool to push the upper end portion of the crude
material,u- U• ~
[Claim 5] l'he molding method for the ;- press cupshaped
member according to any, one of claims 1 to 3,
comprising
a re-thickening processing process of carrying
out a plurality of thickening processings between the
second process and the third process,
- 38 -
wherein, in the re-thickening processing process,
the (n-l)th ("n• is an integer equal to or more than
2) thickening processing is a processing in which, by
using an (n+l)th mold having a column-shaped (3xn-
2)th upper tool, a cylinder-shaped (3xn-l)th upper
tool disposed along an outer periphery of the (3xn-
2)th upper tool and formed of an upper tool inclined
portion whose tip surface is inclined in a manner to
approach a center axis as going downward, a cylindershaped
(3xn)th upper tool disposed along an outer
periphery of the (3xn-l) th upper tool, and an nth
lower tool which is a hole portion to allow entering
of the (3xn-2)th upper tool, the (3xn-l)th upper tool,
and the (3xn)th upper tool, the hole portion being
formed of a hole portion vertical wall portion
extending along the (3xn)th upper tool entering the
inside of the hole portion, a hole portion inclined
portion continuously provided in a lower end portion
of the hole portion vertical wall portion and
inclined in a manner to approach a center axis as
going downward, and a hole portion bottom surface
portion continuously provided in a lower end portion
of the.hole portion inclined portion and,extending in
a direct·ion orthogonal to the center axis;· the
respective center axes thereof being disposed
coaxially to one another, a part of the crude
material is made to flow into a space formed between
the upper tool inclined portion and the hole portion
inclined portion to further thicken that part by
- 39 -
relatively moving the (3xn-l)th upper tool in a
direction to approach the nth lower tool in a state
where the crude material is compressed by the (3xn-
2)th upper tool and the nth lower tool and thereafter
relatively moving the (3xn)th upper tool in the
direction to approach the nth lower tool and pushing
an upper end portion of the crude material, and
wherein the nth thickening processing is a
processing in which, by using an (n+2)th mold having
a column-shaped (3x(n+l)-2)th upper tool, a cylindershaped
(3x(n+l)-l)th upper tool disposed along an
outer periphery of the (3x(n+l)-2)th upper tool and
formed of an upper tool inclined portion whose tip
surface is inclined in a manner to approach a center
axis as going downward, a cylinder-shaped (3x(n+l))th
upper tool disposed along an outer periphery of the
(3x(n+l)-l)th upper tool, and an (n+l)th lower tool
which is a hole portion to allow entering of the
(3x(n+l)-2)th upper tool, the (3x(n+l)-l)th upper tool,
and the (3x(n+l))th upper tool, the hole portion
being formed of a hole portion vertical wall portion
extending along the (3x(n+l))th upper tool entering
the hole portion, a hole portion inc'lined portion
cont~nuously provided in a lower end p6rtion of the
hole portion vertical wall portion and inclined in a
manner to approach a center axis as going downward,
and a hole portion bottom portion continuously
provided in a lower end portion of the hole portion
inclined portion and extending in a direction
orthogonal to the center axis, the respective center
axes thereof being disposed coaxially to one another,
and an angle of inclination of the upper tool
inclined portion in_the (3x(n+1)-1)th upper to61
being smaller than an angle of inclination of the
upper tool inclined portion in the (3xn-1)th upper
tool, a part of the crude material is made to flow
into a space formed between the upper tool inclined
portion and the hole portion inclined portion to
further thicken that part, by relatively moving the
(3x(n+1)-1)th upper tool in a direction to approach
the (n+1)th lower tool in a state where the crude
material is compressed by the (3x(n+1)-2)th upper
tool and the (n+1)th lower tool and thereafter
I
relatively moving the (3(<(n+1) )th upper tool in the
direction to apprciach the (n+1)th lower tool and
pushing an upper end portion of the crude material.
[Claim 6] The press molding method for the cupshaped
member according to any one of claims 1 to 5,
wherein completion of at least either one of the
first process and the second process is judged from a
predetermined position of the tool.
[claim 7] The press molding method for the cupshaped
member accoiding to any one~of claims 1 to 5,
. wherein completion of at least either one of th~
first process and the second process is judged from a
predetermined ~oad amount of the press molding
apparatus.