TECHNICAL FIELD
[0001]
The present disclosure relates to a die, more specifically, a die used for hot
pressing.
BACKGROUND ART
[0002]
As a method for forming a high-strength part such as automobile body parts,
hot pressing has been known. In the hot pressing, a heated blank is pressed with
dies attached to the press machine, and the blank is cooled and quenched in the dies.
[0003]
Patent Literature 1 discloses a press tooling for hot pressing. This press
tooling is constituted of a punch that is a lower die and a die set that is an upper die.
In the punch and the die set, a plurality of cooling water pipes that penetrate them in
the longitudinal direction are provided. Moreover, in the punch and the die set, a
plurality of refrigerant flow channels that penetrate them in the longitudinal direction
are provided. To each of the refrigerant flow channels, a plurality of
communication paths, which open at the forming surface of the punch or the die set,
are connected.
[0004]
When press working is performed by the press tooling of Patent Literature 1,
first, water as the refrigerant is made to flow in each cooling water pipe to cool the
punch and the die set to a predetermined temperature. Next, a heated blank is
placed between the punch and the die set, and the die set is lowered to deform the
blank. When the die set reaches the bottom dead center, introduction of refrigerant
into each refrigerant flow channel is started. The refrigerant introduced into the
refrigerant flow channel is ejected from the forming surface through a
communication path. According to Patent Literature 1, the blank is cooled by direct
2
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contact with the cooled die set and punch, and by the refrigerant ejected from the
forming surface.
[0005]
Patent Literatures 2 to 4 also disclose a die for hot pressing. The die of
Patent Literature 2 includes an outer shape block having a forming surface, and an
insert block to be inserted into the outer shape block. The insert block has a
plurality of grooves for flowing the refrigerant, in its outer surface. Each groove is
formed in the outer surface of the insert block such that it crosses substantially the
entire insert block in a lateral direction (width direction).
[0006]
The die of Patent Literature 3 includes a lower die, and an upper die formed
of a material different from that of the lower die. The upper die is placed on the
lower die and has a plurality of grooves for flowing refrigerant, on its underside.
These grooves are formed on the underside of the upper die so as to traverse
substantially the entire upper die in the lateral direction (width direction).
[0007]
The die of Patent Literature 4 includes a first split body having a forming
surface, and a second split body to be combined with the first split body. The first
split body has a groove that opens on the second split body side. In the die of
Patent Literature 4, a flow channel for circulating refrigerant is formed of a portion
surrounded by the groove of the first split body, and the second split body.
CITATION LIST
PATENT LITERATURE
[0008]
Patent Literature 1: Japanese Patent Application Publication No. 2014-205164
Patent Literature 2: Japanese Patent Application Publication No. 2013-99774
Patent Literature 3: Japanese Patent Application Publication No. 2013-119119
Patent Literature 4: Japanese Patent Application Publication No. 2018-83223
SUMMARY OF INVENTION
TECHNICAL PROBLEM
3
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[0009]
For example, a plurality of cooling water pipes are provided in each die of
Patent Literature 1 to cool the press tooling itself. Since especially the forming
surface of the die becomes high temperature during hot pressing, such cooling water
pipes are usually disposed near the forming surface of the press tooling. However,
in this case, since a large number of spaces are produced in the vicinity of the
forming surface, the load bearing capacity of the forming surface becomes
insufficient. In other words, the strength of the die decreases.
[0010]
An object of the present disclosure is to provide a die that is able to adjust the
temperature of the forming surface, as well as to ensure strength.
SOLUTION TO PROBLEM
[0011]
A die according to the present disclosure includes a forming surface. The
die includes a die body and a removable shell. The die body includes a supply flow
channel. The supply flow channel is formed inside the die body. One end of the
supply flow channel opens at the surface of the die body. The supply flow channel
is to be supplied with a fluid for temperature adjustment. The removable shell is
mounted removably to the surface of the die body. The removable shell includes an
outer surface that constitutes at least a part of the forming surface of the die. A
temperature adjustment space is provided in the surface of the die body or in the
removable shell. The temperature adjustment space is in communication with the
supply flow channel. The removable shell is divided into a plurality of shell pieces.
The plurality of shell pieces are arranged in a direction intersecting the longitudinal
direction of the die on the surface of the die body.
ADVANTAGEOUS EFFECTS OF INVENTION
[0012]
According to the present disclosure, it is possible to adjust the temperature of
the forming surface of the die, as well as to ensure the strength of the die.
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BRIEF DESCRIPTION OF DRAWINGS
[0013]
[FIG. 1] FIG. 1 is a schematic diagram showing a press machine.
[FIG. 2] FIG. 2 is a cross-sectional view of the die (lower die) according to the first
embodiment.
[FIG. 3] FIG. 3 shows a removable shell, which is included in the die shown in FIG.
2, viewed from the inner surface side.
[FIG. 4] FIG. 4 is a cross-sectional view of the die (upper die) according to the first
embodiment.
[FIG. 5] FIG. 5 is a cross-sectional view of the die (lower die) according to the
second embodiment.
[FIG. 6] FIG. 6 is a cross-sectional view of the die (upper die) according to the
second embodiment.
[FIG. 7] FIG. 7 shows a removable shell, which is included in the die shown in FIG.
5, viewed from the inner surface side.
[FIG. 8] FIG. 8 shows the removable shell shown in FIG. 7, viewed from the outer
surface side.
[FIG. 9] FIG. 9 is a diagram for explaining a die according to a variation of the
embodiments.
[FIG. 10] FIG. 10 is another diagram for explaining the die according to the variation.
[FIG. 11] FIG. 11 is a cross-sectional view of a die according to another variation of
the embodiments.
DESCRIPTION OF EMBODIMENTS
[0014]
The die according to an embodiment includes a forming surface. The die
includes a die body and a removable shell. The die body includes a supply flow
channel. The supply flow channel is formed inside the die body. One end of the
supply flow channel opens at the surface of the die body. The supply flow channel
is to be supplied with a fluid for temperature adjustment. The removable shell is
mounted removably to the surface of the die body. The removable shell includes an
outer surface that constitutes at least a part of the forming surface of the die. A
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temperature adjustment space is provided in the surface of the die body or in the
removable shell. The temperature adjustment space is in communication with the
supply flow channel. The removable shell is divided into a plurality of shell pieces.
The plurality of shell pieces are arranged in a direction intersecting the longitudinal
direction of the die on the surface of the die body (first configuration).
[0015]
In the die according to the first configuration, the temperature of the forming
surface is adjusted by a fluid for temperature adjustment which has flown into the
temperature adjustment space from the supply flow channel. In other words, the
temperature of the forming surface of the die is directly adjusted by the fluid in the
temperature adjustment space. This temperature adjustment space is located in a
distributed manner in the surface of the die body, or in the removable shell that can
be mounted to or removed from the surface of the die body. Therefore, the working
load during press working is distributed over the contact surface between the die
body and the removable shell. Therefore, it is possible to adjust the temperature of
the forming surface as well as to secure the strength of the die.
[0016]
On the forming surface of the die, the degree of wear varies depending on the
region. For example, among the forming surfaces of the die, the portion that rubs
with the blank wears faster than the portion where the blank is simply sandwiched.
According to the first configuration, the removable shell mounted removably to the
die body is divided into a plurality of shell pieces. Therefore, the removable shell
can be partially replaced. For example, among the plurality of shell pieces included
in the removable shell, the forming surface can be partially repaired by replacing the
worn shell piece. Therefore, it is not necessary to repair the entire die or prepare a
new die, and thus repair of the die can be easily performed.
[0017]
The removable shell may further include a through hole. One end of the
through hole opens into the temperature adjustment space. Further, the other end of
the through hole opens at the outer surface of the removable shell (second
configuration).
[0018]
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According to the second configuration, the fluid flowing into the temperature
adjustment space can be ejected from the outer surface of the removable shell.
Therefore, the fluid for temperature adjustment can be supplied to the formed article
on the die.
[0019]
In general, since the material strength of a die body is high, it is not easy to
form a through hole in a die for ejecting the fluid for temperature adjustment from
the forming surface. In particular, the diameter required for the through hole for
ejection is small from the viewpoint of improving the flow velocity. In order to
form such a through hole in the die, complex path processing is required to gradually
reduce the hole diameter from the supply flow channel of the fluid for temperature
adjustment in order to avoid increase of pressure loss. In addition, since the length
of the through hole tends to be large, it is not practical to accurately form a large
number of through holes in the die in terms of the difficulty in processing, as well as
in terms of cost. For example, conventionally, when a small diameter through hole
is required, work such as first forming a large diameter through hole in the die, and
disposing a screw or the like having a small diameter through hole in the large
diameter through hole is performed. In contrast to this, according to the second
configuration, a through hole for ejecting the fluid for temperature adjustment from
the forming surface may be formed in the removable shell. The removable shell
constitutes a near surface portion of the die, and has a small thickness. Thus, a
through hole of the desired diameter can be easily formed.
[0020]
The temperature adjustment space is preferably formed by a groove provided
in the inner surface of the removable shell. The inner surface of the removable
shell is the surface of the die body side (third configuration).
[0021]
When the temperature adjustment space is constituted by the groove in the
inner surface of the removable shell, the thickness of the removable shell can be
reduced compared with, for example, a case where the removable shell is formed into
a hollow box shape. Moreover, since a portion other than the groove of the inner
surface of the removable shell is supported by the surface of the die body, and the
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supported area of the removable shell increases, deformation of the removable shell
can be suppressed.
[0022]
Hereinafter, embodiments of the present disclosure will be described while
referring to the drawings. The same or equivalent configuration is designated by
the same reference symbol in each figure, and the same description will not be
repeated.
[0023]

[Configuration of press machine]
FIG. 1 is a schematic diagram showing a press machine 100. The press
machine 100 is provided with dies 10 and 20. FIG. 1 shows the press machine 100
viewed from the front. In the present embodiment, the direction perpendicular to
the paper surface of FIG. 1 is a depth direction of the press machine 100.
[0024]
The press machine 100 includes a main body frame 30, a slide 40, a bolster 50,
and a base plate 60.
[0025]
The slide 40 is mounted to the main body frame 30. The slide 40 moves up
and down with respect to the main body frame 30 by operation of a hydraulic
cylinder, a flywheel, or the like housed in the main body frame 30. The slide 40
holds the die 20.
[0026]
The bolster 50 is disposed below the slide 40. The base plate 60 is fixed
onto the bolster 50. The base plate 60 has a concave shape. The die 10 is
mounted to the base plate 60. The base plate 60 adjusts the position of the die 10 in
the vertical direction. The die 10 faces the die 20.
[0027]
The dies 10 and 20 extend in the depth direction of the press machine 100.
Hereinafter, with respect to the dies 10 and 20, the depth direction of the press
machine 100 is referred to as the longitudinal direction, and a direction perpendicular
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to the longitudinal direction and the vertical direction is referred to as a lateral
direction.
[0028]
FIG. 2 is a cross-sectional view showing the outline configuration of the die
10. A cross section is a section perpendicular to the longitudinal direction. As
shown in FIG. 2, the die 10 includes a die body 11, a die base 12, and a removable
shell 13.
[0029]
In the present embodiment, the die body 11 has a schematic hat shape viewed
from the longitudinal direction. In other words, the die body 11 includes a punch
part 111 and flange parts 112.
[0030]
The punch part 111 is disposed at the middle in the lateral direction of the die
body 11. The punch part 111 includes a top surface 111a and side surfaces 111b.
The side surfaces 111b are located on both sides of the top surface 111a. Each of
the side surfaces 111b is inclined with respect to the vertical direction outward in the
lateral direction as they are closer to the bottom from the top surface 111a. Each
flange part 112 protrudes outward in the lateral direction from the punch part 111.
The upper surface 112a of the flange part 112 is connected to the lower end of the
side surface 111b of the punch part 111.
[0031]
The die body 11 includes a plurality of supply flow channels 113 and a
plurality of discharge flow channels 114. Each of the supply flow channels 113 and
the discharge flow channels 114 penetrates the die body 11 in the vertical direction.
The upper ends of the supply flow channel 113 and the discharge flow channel 114
open at the surface of the die body 11. More specifically, the upper ends of the
supply flow channel 113 and the discharge flow channel 114 open at the top surface
111a of the punch part 111 or the upper surface 112a of the flange part 112. The
lower ends of the supply flow channel 113 and the discharge flow channel 114 open
at the lower surface of the die body 11.
[0032]
9
- 9 -
Of the plurality of supply flow channels 113, two branch supply paths 1131
are provided on the supply flow channel 113 that opens at the top surface 111a of the
punch part 111. Each of the branch supply paths 1131 extends from the supply
flow channel 113 in the lateral direction of the die 10. Each branch supply path
1131 may be inclined or bent with respect to the lateral direction of the die 10. One
of the two branch supply paths 1131 opens at one side surface 111b of the punch part
111. The other branch supply path 1131 opens at the other side surface 111b of the
punch part 111.
[0033]
In the discharge flow channel 114 that opens at the top surface 111a of the
punch part 111 among the plurality of discharge flow channels 114, two branch
discharge paths 1141 are provided. Each of the branch discharge paths 1141
extends from the discharge flow channel 114 in the lateral direction of the die 10.
Each branch discharge path 1141 may be inclined or bent with respect to the lateral
direction of the die 10. One of the two branch discharge paths 1141 opens at one
side surface 111b of the punch part 111. The other branch discharge path 1141
opens at the other side surface 111b of the punch part 111.
[0034]
The sectional shapes of the supply flow channel 113, the branch supply path
1131, the discharge flow channel 114, and the branch discharge path 1141 are, for
example, circular. However, the sectional shapes of the supply flow channel 113,
the branch supply path 1131, the discharge flow channel 114, and the branch
discharge path 1141 may be other shapes.
[0035]
The cross-sectional areas of the supply flow channel 113, the branch supply
path 1131, the discharge flow channel 114, and the branch discharge path 1141 may
be different from each other or may be the same. Each of the supply flow channel
113, the branch supply path 1131, the discharge flow channel 114, and the branch
discharge path 1141 may be configured such that the cross-sectional area is constant
throughout, or such that the cross-sectional area varies on the way.
[0036]
10
- 10 -
The die body 11 is placed on the die base 12. The die body 11 is mounted to
the die base 12. The die base 12 has, for example, a substantially cuboid outer
shape.
[0037]
A concave conduit 122 is formed in the upper surface 121 of the die base 12.
The conduit 122 is, for example, a plurality of grooves provided in the upper surface
121 corresponding to the supply flow channels 113 of the die body 11. However,
the configuration of the conduit 122 is not limited thereto. The conduit 122 is
supplied with a fluid for temperature adjustment. In the present embodiment, the
fluid for temperature adjustment is refrigerant for cooling the die 10. The
refrigerant is typically water. The lower ends of the supply flow channels 113 are
connected to the conduit 122.
[0038]
A conduit 123 which is different from the conduit 122 is also formed in the
die base 12. The conduit 123 is, for example, a space provided on the lower surface
124 side of the die base 12. The conduit 123 is connected to the discharge flow
channels 114 of the die body 11 by a plurality of connection paths 125. The
connection paths 125 are provided corresponding to the discharge flow channels 114,
in the die base 12.
[0039]
The removable shell 13 is a member which is separate from the die body 11.
The removable shell 13 is formed of, for example, a metal. The material of the
removable shell 13 may be the same as or different from the material of the die body
11. The removable shell 13 is mounted removably to the surface of the die body 11.
Although not particularly limited, the removable shell 13 is fixed to the surface of the
die body 11 with bolts after it is positioned with a knock pin, for example. The
outer surface 131 of the removable shell 13 constitutes at least a part of the forming
surface of the die 10. The inner surface 132 of the removable shell 13 is located on
the die body 11 side. The inner surface 132 is provided with a groove 133. The
groove 133 forms a temperature adjustment space S1 for adjusting the temperature of
the forming surface of the die 10.
[0040]
11
- 11 -
The thickness of the removable shell 13 is preferably 5 mm to 10 mm. The
thickness of the removable shell 13 refers to the length from the contact surface
between the removable shell 13 and the die body 11 to the outer surface 131 of the
removable shell 13. In the example of the present embodiment, the removable shell
13 is divided into a plurality of shell pieces 134. In other words, the removable
shell 13 is constituted of the plurality of shell pieces 134. In the die 10 according to
the present embodiment, the plurality of shell pieces 134 are provided for one die
body 11.
[0041]
The plurality of shell pieces 134 are arranged in a direction intersecting the
longitudinal direction of the die 10 on the surface of the die body 11. Therefore,
when viewed in a cross section of the die 10, an end face (split line of the removable
shell 13) of each shell piece 134 stands up from the surface of the die body 11 toward
the outer surface 131 of the removable shell 13. In the cross-sectional view of the
die 10, the length of each shell piece 134 in the direction along the forming surface
of the die 10 is, of course, smaller than the entire length of the forming surface in the
aforementioned direction. The shell pieces 134 are removable with respect to the
die body 11, respectively. In other words, each shell piece 134 can be mounted to
the die body 11 as well as can be removed from the die body 11.
[0042]
In the present embodiment, the removable shell 13 includes shell pieces 134a
to 134c. The shell pieces 134a to 134c are mounted to any of the surfaces 111a,
111b, and 112a being a plurality of surfaces constituting the surface of the die body
11 and having different orientations from each other. In the example of FIG. 2, the
shell piece 134a is mounted to the top surface 111a of the punch part 111. The shell
piece 134a is removable substantially in the normal direction with respect to the top
surface 111a of the punch part 111. The shell piece 134b is mounted to each side
surface 111b of the punch part 111. The shell piece 134b is removable substantially
in the normal direction with respect to each side surface 111b of the punch part 111.
The shell piece 134c is mounted to the upper surface 112a of the flange part 112.
The shell piece 134c is removable substantially in the normal direction with respect
to the upper surface 112a of the flange part 112. Of the upper surface 112a of the
12
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flange part 112, the portion to which the shell piece 134c is mounted has a concave
shape compared to other portions.
[0043]
FIG. 3 shows the removable shell 13 viewed from the inner surface 132 side.
In FIG. 3, one of the plurality of shell pieces 134 included in the removable shell 13
is exemplified.
[0044]
As shown in FIG. 3, a groove 133 is formed in the inner surface 132 of the
removable shell 13. The groove 133 is formed for each shell piece 134. The
depth of the groove 133 and the distance from the outer surface 131 to the groove
133 in each shell piece 134 are preferably equal to the depth of the groove 133 and
the distance from the outer surface 131 to the groove 133 in another shell piece 134.
Although not particularly limited, the groove 133 is formed in each shell piece 134,
for example, so as to reciprocate between the opposite side edges. The groove 133
is in communication with the supply flow channel 113 and the discharge flow
channel 114. For example, a supply flow channel 113 or a branch supply path 1131
is connected at one end of the groove 133, and a discharge flow channel 114 or a
branch discharge path 1141 is connected to the other end of the groove 133.
[0045]
FIG. 4 is a cross sectional view showing the schematic configuration of the
die 20. As shown in FIG. 4, the die 20 includes a forming surface having an
upwardly concave shaped corresponding to the die 10 including a forming surface
having an upwardly convex shape. The die 20 includes a die body 21, a die base 22,
and a removable shell 23.
[0046]
The die body 21 has a concave portion 212 in its lower surface 211. The die
body 21 includes a plurality of supply flow channels 213 and a plurality of discharge
flow channels 214. Some supply flow channels 213 are provided with a branch
supply path 2131. A branch discharge path 2141 is provided in some discharge
flow channels 214. Since the configuration of the supply flow channel 213, the
branch supply path 2131, the discharge flow channel 214, and the branch discharge
path 2141 is the same as the configuration of the supply flow channel 113, the branch
13
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supply path 1131, the discharge flow channel 114, and the branch discharge path
1141 (FIG. 2) in the die body 11 of the die 10, detailed description thereof will be
omitted.
[0047]
The die base 22 has, for example, a substantially cuboid outer shape. The
die base 22 is disposed above the die body 21. The die body 21 is mounted to the
lower surface 221 of the die base 22. In the lower surface 221 of the die base 22, a
conduit 222 similar to the conduit 122 (FIG. 2) in the die base 12 of the die 10 is
formed. The conduit 222 is supplied with a fluid for temperature adjustment. In
the present embodiment, the fluid for temperature adjustment is refrigerant for
cooling the die 20, and is typically water. On the upper surface 224 side of the die
base 22, a conduit 223 and connection paths 225 similar to the conduit 123 and the
connection paths 125 (FIG. 2) in the die base 12 of the die 10 are formed.
[0048]
The removable shell 23 is configured in the same way as the removable shell
13 (FIG. 2) of the die 10. The removable shell 23 is a member separate from the
die body 21. The removable shell 23 is formed of, for example, a metal. The
material of the removable shell 23 may be the same as or different from the material
of the die body 21. The removable shell 23 is mounted removably to the surface of
the die body 21. Although not particularly limited, the removable shell 23 is fixed
to the surface of the die body 21 by bolts after being positioned with a knock pin, for
example. The outer surface 231 of the removable shell 23 constitutes at least a part
of the forming surface of the die 20. The inner surface 232 of the removable shell
23 is located on the die body 21 side. The inner surface 232 is provided with a
groove 233. The groove 233 forms a temperature adjustment space S2 for adjusting
the temperature of the forming surface of the die 20.
[0049]
The thickness of the removable shell 23 is preferably 5 mm to 10 mm. The
thickness of the removable shell 23 refers to the length from the contact surface
between the removable shell 23 and the die body 21 to the outer surface 231 of the
removable shell 23. The removable shell 23 is divided into a plurality of shell
pieces 234. In other words, the removable shell 23 is constituted of the plurality of
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- 14 -
shell pieces 234. In the die 20 according to the present embodiment, the plurality of
shell pieces 234 are provided for one die body 21.
[0050]
The plurality of shell pieces 234 are arranged in a direction intersecting the
longitudinal direction of the die 20, on the surface of the die body 21. Therefore,
when viewed in a cross section of the die 20, the end face of each shell piece 234
(division line of the removable shell 23) stands up from the surface of the die body
21 toward the outer surface 231 of the removable shell 23. In the cross-sectional
view of the die 20, the length of each of the shell pieces 234 in the direction along
the forming surface of the die 20 is, of course, smaller than the entire length of the
forming surface in the aforementioned direction. The shell pieces 234 are
removable with respect to the die body 21, respectively. In other words, for each
shell piece 234, it can be mounted to the die body 21 and can be removed from the
die body 21. Each of the shell pieces 234 is formed with a groove 233 similar to
that of the shell piece 134 (FIG. 3) of the removable shell 13 in the die 10. The
depth of the groove 233 and the distance from the outer surface 231 to the groove
233 in each shell piece 234 are preferably equal to the depth of the groove 233 and
the distance from the outer surface 231 to the groove 233 in another shell piece 234.
[0051]
In the present embodiment, the removable shell 23 includes shell pieces 234a
to 234c. The shell pieces 234a to 234c are mounted to any of the surfaces
constituting the surface of the die body 21 and having different orientations from
each other. In the example of FIG. 4, the shell piece 234a is mounted to the bottom
surface of the concave portion 212 of the die body 21. The shell piece 234a is
removable substantially in the normal direction with respect to the bottom surface of
the concave portion 212. The shell piece 234b is mounted to each side surface of
the concave portion 212. The shell piece 234b is substantially removable with
respect to each side surface of the concave portion 212. The shell pieces 234c are
disposed on both outsides of the concave portion 212 in the lateral direction of the
die 20 and are mounted to the lower surface 211 of the die body 21. Each shell
piece 234c is removable substantially in the normal direction with respect to the
lower surface 211 of the die body 21.
15
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[0052]
[Operation of press machine]
Next, the operation of the press machine 100 when producing a formed article
will be described. Referring to FIG. 1, first, a heated blank (not illustrated) is
placed on the die 10. Next, by lowering the slide 40, the die 20 is made to reach a
bottom dead center. Thereby, the blank is pressed by the die 20 and the die 10, and
the formed article is produced.
[0053]
When blanks are pressed repeatedly, the temperature of the forming surfaces
of the dies 10, 20 rise due to the heat of the heated blanks. Therefore, the dies 10,
20 are cooled. Typically, the dies 10, 20 are continuously cooled while the formed
articles are produced. However, the dies 10, 20 can also be temporarily cooled.
[0054]
Referring to FIG. 2 again, when cooling the die 10, the refrigerant is
continuously introduced to the conduit 122 of the die base 12, for example, by fluid
pressure feeding means (not illustrated) provided outside the die 10. Examples of
the fluid pressure feeding means include pumps and cylinders disposed between the
conduit 122 and a refrigerant tank. The conduit 122 may be directly connected to
the water supply. The refrigerant introduced into the conduit 122 is supplied to
each supply flow channel 113 of the die body 11. The refrigerant flows into the
removable shell 13 through the supply flow channel 113. More specifically, the
refrigerant flows into the groove 133 of each shell piece 134a to 134c from the
supply flow channel 113 or the branch supply path 1131.
[0055]
As a result of the refrigerant flowing through the groove 133 of each shell
piece 134a to 134c, the heat of the removable shell 13 is dissipated. Since the
removable shell 13 is thin, the outer surface 131, that is, the forming surface of the
die 10 is also sufficiently cooled. The refrigerant which has flown through the
groove 133 is discharged from the removable shell 13 through the discharge flow
channel 114 or the branch discharge path 1141 of the die body 11. The refrigerant
is collected in the conduit 123 of the die base 12 through the discharge flow channels
114 of the die body 11 and the connection paths 125 of the die base 12 and
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- 16 -
discharged from the conduit 123. The refrigerant discharged from the conduit 123
may be either discarded or circulated for use.
[0056]
Referring to FIG. 4, when cooling the die 20, the refrigerant is continuously
introduced into the conduit 222 of the die base 22, for example, by the abovedescribed
fluid pressure feeding means (not illustrated). The refrigerant introduced
into the conduit 222 is supplied to each supply flow channel 213 of the die body 21.
The refrigerant flows into the removable shell 23 through the supply flow channel
213. More specifically, the refrigerant flows into the groove 233 of each shell piece
234a to 234c from the supply flow channel 213 or the branch supply path 2131.
[0057]
As a result of refrigerant flowing through the groove 233 of each shell piece
234a to 234c, heat of the removable shell 23 is dissipated. Since the removable
shell 23 is thin, the outer surface 231, that is, the forming surface of the die 20 is also
sufficiently cooled. The refrigerant which has flown through the groove 233 is
discharged from the removable shell 23 through the discharge flow channel 214 or
the branch discharge path 2141 of the die body 21. The refrigerant is collected in
the conduit 223 of the die base 22 through the discharge flow channels 214 of the die
body 21 and the connection paths 225 of the die base 22 and discharged from the
conduit 223. The refrigerant discharged from the conduit 223 may be either
discarded or circulated for use.
[0058]
[Advantageous effects of the first embodiment]
In the dies 10and 20 according to the present embodiment, the forming
surfaces are cooled by the refrigerant which has flown into each groove 133 of the
removable shell 13 and each groove 233 of the removable shell 23. In other words,
the groove 133 of the removable shell 13 and the groove 233 of the removable shell
23 function as the temperature adjustment spaces S1, S2, respectively, for cooling the
forming surfaces of the dies 10, 20. Thus, by providing the temperature adjustment
spaces S1, S2 in a distributed manner in the removable shells 13, 23 constituting the
forming surfaces of the dies 10, 20, the working load during press working can be
distributed over the contact surfaces between the die bodies 11, 21 and the removable
17
- 17 -
shells 13, 23. Therefore, according to the dies 10 and 20 of the present embodiment,
it is possible to cool the forming surfaces of the dies 10, 20, as well as to secure the
strength of the dies 10, 20.
[0059]
In the dies 10 and 20 according to the present embodiment, the thicknesses of
the removable shells 13, 23 mounted removably to the die bodies 11, 21 are small.
The thicknesses of the removable shells 13, 23 are, for example, 5 mm to 10 mm.
Therefore, it is possible to reduce the amount of deformation of the removable shells
13, 23 due to the working load during press working. Further, the small thicknesses
of the removable shells 13, 23 suppress decrease in sectional rigidity of the die
bodies 11, 21. Therefore, it is possible to secure the rigidity and the load bearing
capacity of the dies 10 and 20.
[0060]
Reducing the thicknesses of the removable shells 13, 23 allow to reduce the
heat capacity of the removable shells 13, 23. Therefore, the removable shells 13, 23,
which constitute the forming surfaces of the dies 10, 20, become easier to be cooled.
[0061]
In the present embodiment, in particular, grooves 133, 233 are formed in the
inner surfaces 132, 232 of the removable shells 13, 23, and the temperature
adjustment spaces S1, S2 are constituted of the grooves 133, 233. Therefore, the
thicknesses of the removable shells 13, 23 can be further reduced, and the
displacement in the thickness direction of the removable shells 13, 23 can be reduced.
Further, in the inner surfaces 132, 232 of the removable shells 13, 23, not only a
peripheral edge portion but also a portion between grooves 133 or between grooves
233 is supported by the die body 11 or 21, thus increasing the supported area of the
removable shells 13, 23 and suppressing the deformation of the removable shells 13,
23. Therefore, it is possible to further increase the strength of the dies 10, 20.
[0062]
When the grooves 133, 233 as the temperature adjustment spaces S1, S2 are
formed in the inner surfaces 132, 232 of the removable shells 13, 23 instead of in the
surfaces of the die bodies 11, 21 as in the present embodiment, repairability of the
dies 10, 20 is improved. In other words, even if deformation such as wear and dents
18
- 18 -
of the forming surface occurs in the dies 10, 20, damage by such deformation is
unlikely to extend to the die bodies 11, 21 having no groove. Therefore, the dies 10,
20 can be repaired only by replacing the removable shells 13, 23. Even if damage
by such deformation extends to the die bodies 11, 21, the die bodies 11, 21 only have
flow channels 113, 114, 213, 214 inside thereof, and have no groove in their surfaces,
so that the die bodies 11, 21 can be easily repaired compared to when there is a
groove in the surfaces of the die bodies 11, 21. Further, it is easier to provide the
grooves 133, 233 in the removable shells 13, 23 than to provide a groove in the die
bodies 11, 21.
[0063]
In the dies 10 and 20 according to the present embodiment, the groove 133 as
the temperature adjustment space S1 is in communication with a supply flow channel
113 and a discharge flow channel 114 of the die body 11, and the groove 233 as the
temperature adjustment space S2 is in communication with a supply flow channel
213 and a discharge flow channel 214 of the die body 21. When cooling the
forming surfaces of the dies 10, 20, fresh refrigerant is supplied from the supply flow
channels 113, 213 to the temperature adjustment spaces S1, S2, and the refrigerant
whose temperature has risen due to heat exchange with the forming surfaces is
discharged from the discharge flow channels 114, 214. In other words, since the
refrigerant in the temperature adjustment spaces S1, S2 is constantly replaced, the
forming surfaces of the dies 10, 20 can be appropriately cooled.
[0064]
In the dies 10 and 20 according to the present embodiment, the removable
shell 13 is divided into the plurality of shell pieces 134 and the removable shell 23 is
divided into the plurality of shell pieces 234. The shell pieces 134, 234 are
removable for the die bodies 11, 21, respectively. Therefore, for example, if some
of the plurality of shell pieces 134, 234 are worn, only the worn shell pieces 134, 234
can be replaced. In other words, partial repair of the dies 10, 20 can be performed.
Therefore, when the forming surfaces of the dies 10, 20 are partially worn, it is not
necessary to repair the entire dies 10, 20 or prepare a new die, and thereby the
repairability of the dies 10, 20 can be improved.
[0065]
19
- 19 -
In the present embodiment, the temperature adjustment spaces S1, S2 are used
to cool the dies 10, 20, but the temperature adjustment spaces S1, S2 can also be used
to keep the temperature of the dies 10, 20. When keeping the temperature of the
dies 10, 20, for example, high-temperature oil or the like may be selected as the fluid
for temperature adjustment.
[0066]

FIGS. 5 and 6 are cross-sectional views of dies 10A and 20A according to the
second embodiment. The die 10A differs from the die 10 (FIG. 2) according to the
first embodiment in the configuration of the removable shell 13A. The die 20A
differs from the die 20 (FIG. 4) according to the first embodiment in the
configuration of the removable shell 23A.
[0067]
Referring to FIG. 5, the removable shell 13A of the die 10A has grooves 133a,
133b in the inner surface 132. The groove 133a functions as a temperature
adjustment space S1. The removable shell 13A further includes a plurality of
through holes 135a, 135b.
[0068]
One end of each through hole 135a opens in the groove 133a as the
temperature adjustment space S1. The other end of each through hole 135a opens at
the outer surface 131 of the removable shell 13A. One end of each through hole
135b opens in the groove 133b different from the groove 133a as the temperature
adjustment space S1. The other end of each through hole 135b opens at the outer
surface 131 of the removable shell 13A as in the same manner as the through hole
135a.
[0069]
The removable shell 13A is divided into a plurality of shell pieces 134A.
The removable shell 13A is constituted of the plurality of shell pieces 134A. The
removable shell 13A includes shell pieces 134Aa to 134Ac corresponding to the top
surface 111a and both side surfaces 111b of the punch part 111, and the upper
surface 112a of each flange part 112, respectively. The shell pieces 134Aa to
134Ac are arranged in the direction intersecting the longitudinal direction of the die
20
- 20 -
10A on the surface of the die body 11 in the same manner as the shell pieces 134a to
134c (FIG. 2) in the first embodiment.
[0070]
A plurality of convex portions 131a are provided on the outer surface 131 of
the removable shell 13A. The convex portions 131a are provided at a substantially
equal density on the outer surface 131. These convex portions 131a can be formed,
for example, by etching the outer surface 131. In the present embodiment, the
convex portions 131a are provided over the entire area of the outer surface 131. In
other words, the plurality of convex portions 131a are formed in each of the plurality
of shell pieces 134A. However, these convex portions 131a may be formed only in
some shell pieces 134A. The convex portion 131a is preferably provided so as not
to interfere with the through holes 135a, 135b.
[0071]
Referring to FIG. 6, the removable shell 23A of the die 20A has grooves 233a,
233b in the inner surface 232 thereof. The groove 233a functions as a temperature
adjustment space S2. The removable shell 23A further includes a plurality of
through holes 235a, 235b.
[0072]
One end of each through hole 235a opens in the groove 233a as the
temperature adjustment space S2. The other end of each through hole 235a opens at
the outer surface 231 of the removable shell 23A. One end of each through hole
235b opens in the groove 233b different from the groove 233a as the temperature
adjustment space S2. The other end of each through hole 235b opens at the outer
surface 231 of the removable shell 23A in the same manner as the through hole 235a.
[0073]
The removable shell 23A is divided into a plurality of shell pieces 234A.
The removable shell 23A is constituted of the plurality of shell pieces 234A. The
removable shell 23A includes the shell pieces 234Aa to 234Ac corresponding to the
bottom surface and both side surfaces of the concave portion 212, as well as the
lower surface 211 of the die body 21, respectively. The shell pieces 234Aa to
234Ac are arranged in the direction intersecting the longitudinal direction of the die
21
- 21 -
20A on the surface of the die body 21 in the same manner as the shell pieces 234a to
234c (FIG. 4) in the first embodiment.
[0074]
In the same manner as the removable shell 13A (FIG. 5) of the die 10A, a
plurality of convex portions 231a are provided on the outer surface 231 of the
removable shell 23A. The convex portions 231a are provided at a substantially
equal density on the outer surface 231. These convex portions 231a can be formed,
for example, by etching the outer surface 231. In the present embodiment, the
convex portions 231a are provided over the entire area of the outer surface 231. In
other words, the plurality of convex portions 231a are formed in each of the plurality
of shell pieces 234A. However, these convex portions 231a may be formed only in
some shell pieces 234A. It is preferable that the convex portions 231a are provided
so as not to interfere with the through holes 235a, 235b.
[0075]
Hereinafter, referring to FIGS. 7 and 8, detailed configuration of the
removable shell 13A will be described. Since the configuration of the removable
shell 23A (FIG. 6) of the die 20A is roughly the same as the removable shell 13A of
the die 10A, description thereof will be omitted. FIG. 7 shows the removable shell
13A of the die 10A viewed from the inner surface 132 side. FIG. 8 shows the
removable shell 13A of the die 10A viewed from the outer surface 131 side. In
FIGS. 7 and 8, one of the plurality of shell pieces 134A included in the removable
shell 13A is exemplified.
[0076]
As shown in FIG. 7, grooves 133a, 133b are formed in the inner surface 132
of the removable shell 13A. The grooves 133a, 133b are formed for each shell
piece 134A. The depth of the groove 133a and the distance from the outer surface
131 (FIG. 8) to the groove 133a in each shell piece 134A are preferably equal to the
depth of the groove 133a and the distance from the outer surface 131 to the groove
133a in another shell piece 134A. Similarly, the depth of the groove 133b and the
distance from the outer surface 131 to the groove 133b in each shell piece 134A are
preferably equal to the depth of the groove 133b and the distance from the outer
surface 131 to the groove 133b in another shell piece 134A.

We claim:
1. A die including a forming surface, comprising:
a die body including a supply flow channel which is formed inside the die
body, one end of which opens at a surface of the die body, and to which fluid for
temperature adjustment is to be supplied; and
a removable shell which is mounted removably to the surface of the die body
and includes an outer surface constituting at least a part of the forming surface,
wherein
a temperature adjustment space which is in communication with the supply
flow channel is provided in the surface of the die body or in the removable shell,
the removable shell is divided into a plurality of shell pieces, and
the plurality of shell pieces are arranged in a direction intersecting a
longitudinal direction of the die on the surface of the die body.
2. The die according to claim 1, wherein
the removable shell further includes a through hole one end of which opens in
the temperature adjustment space, and the other end of which opens at the outer
surface.
3. The die according to claim 1 or 2, wherein
32
the temperature adjustment space is formed of a groove, the groove being
provided in an inner surface which is a surface on the die body side of the removable
shell.