DESCRIPTION
HAT-SHAPED CROSS-SECTION COMPONENT MANUFACTURING APPARATUS AND
MANUFACTURING METHOD
Technical Field
[0001] The present invention relates to a hat-shaped cross-section component manufacturing
apparatus for and a manufacturing method for manufacturing a component with a hat -shaped
cross-section.
Background Att
[0002] Pressed components with a hat-shaped cross-section profile (also referred to as
"hat-shaped cross-section components" in the present specification), such as front side
members, are known structural members configuring automotive vehicle body framework.
Such hat -shaped cross-section components are formed by performing press working
(drawing) or the like on metal sheet materials (for example, steel sheets) (see, for example,
Japanese Patent Application Laid-Open (JP-A) Nos. 2003-103306, 2004-154859,
2006-015404, and 2008-307557) .
. . SUMMARY OF INVENTION
Technical Problem
[0003] When a hat-shaped cross-section component is formed by drawing a metal sheet, it is
important to remove the hat-shaped cross-section component during demolding while
avoiding deformation as much as possible.
[0004] In consideration of the above circumstances, an object of the present invention is to
obtain a hat-shaped cross-section component manufacturing apparatus capable of suppressing
deformation of a hat-shaped cross-section component during demolding.
Solution to Problem
[0005] A hat-shaped cross-section component manufacturing apparatus that addresses the
above issue includes: a die that includes a forming face that presses both side pmtions of a
metal sheet, and that includes an opening; a punch that is disposed facing the opening of the
die, wherein the punch is disposed inside the opening when a mold is closed, and wherein the
punch includes a forming face that presses a central portion of the metal sheet; a pad that is
disposed inside the opening formed in the die, wherein the pad includes a forming face that
presses and grips the central pmtion of the metal sheet against the punch when the mold is
closed so as to configure a forming face corresponding to the forming face of the punch; a
holder that is disposed facing the die, wherein the holder includes a forming face that presses
and grips both side portions of the metal sheet against the die when the mold is closed so as to
configure a forming face corresponding to the forming face of the die; and a pressure limiting
device that includes a pressure limiting section that moves together with the holder during
demolding after forming a hat-shaped cross-section component with a hat shaped
cross-section, wherein the pressure limiting device is interposed between the pad and the
holder, and wherein the pressure limits pressing on the hat-shaped cross-section component
by the pad and the holder.
[0006] A hat-shaped cross-section component manufacturing method that addresses the
above issue employs the hat-shaped cross-section component manufacturing apparatus above,
and includes: a forming process of forming the hat-shaped cross-section component by
configuring a metal sheet that is curved up-down by gripping the central portion of the metal
sheet between the punch and the pad, and gripping the both side pmiions of the metal sheet
between the die and the holder, and moving the holder and die, and the punch and pad,
up-down relative to each other; and a d<';molding process of demolding the hat-shaped
cross-section component by moving one or both out of the die or the blank holder in a
demolding direction in a state in which the pad and the pressure limiting section are in contact
with each other.
[0007] In the hat-shaped cross-section component manufacturing apparmus and the
hat-shaped cross-section component manufacturing method that address the above issue, the
hat-shaped cross-section component that has a hat-shaped cross-section profile is formed by
gripping the central pmiion of the metal sheet with the punch and the pad, gripping the both
side portions of the metal sheet with the die and the holder, and moving the holder and die,
and the punch and pad, up-down relative to each other. Then, the pressure limiting section is
interposed between the pad and the holder, and one or both out of the die or the blank holder
are moved in a demolding direction in a state in which pressing on the hat-shaped
cross-section component by the pad and the holder is limited. The hat-shaped cross-section
component is therebyremoved fi"om the mold (the holder, the die, the punch, and the pad) in a
state in which pressing of the formed hat-shaped cross-section component between the pad
and the holder is limited during demolding.
Advantageous Effects of Invention
[0008] The hat-shaped cross-section component manufacturing apparatus and manufacturing
method of the present invention exhibit the excellent advantageous effect of enabling
deformation of a hat-shaped cross-section component during demolding to be suppressed.
BIUEF DESCRIPTION OF DRAWINGS
[0009] Fig. 1 A is a perspective view illustrating an example of a curving component
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configured with a hat-shaped cross-section.
Fig. lB is a plan view of the curving component illustrated in Fig. lA, as viewed
from above.
Fig. 1 C is a front view of the curving component illustrated in Fig. I A.
Fig. I D is a side view of the curving component illustrated in Fig. !A, as viewed
from one end portion.
Fig. 2 is a perspective view corresponding to Fig. !A, illustrating a curving
component in order to explain ridge lines at locations corresponding to a concave shaped
curved portion and a convex shaped curved portion.
Fig. 3A is a perspective view illustrating a metal stock sheet before forming.
Fig. 3B is a perspective view illustrating a drawn panel.
Fig. 4 is a perspective view corresponding to Fig. 3B, illustrating locations in the
drawn panel where cracks and creases are liable to occur.
Fig. 5 is an exploded perspective view illustrating relevant portions of a hat-shaped
cross-section component manufacturing apparatus.
Fig. 6A is a cross-section illustrating a stage at the start of processing of the
hat-shap!:_d_cross-section component manufacturing apparatus illustrared in Fig. 5.
Fig. 6B is a cross-section illustrating the hat-shaped cross-section component
manufacturing apparatus illustrated in Fig. 5 at a stage at which a metal stock sheet is gripped
and restrained between a die and pad, and a holder and a punch.
Fig. 6C is a cross-section illustrating a stage at which the punch has been pushed in
from the stage illustrated in Fig. 6B.
Fig. 6D is a cross-section illustrating a state in which the punch has been pushed in
further from the stage illustrated in Fig. 6C, such that the punch has been fully pushed in with
respect to the die.
Fig. 7 is an exploded perspective view illustrating another hat-shaped cross-section
component manufacturing apparatus.
Fig. 8A is a cross-section illustrating the hat-shaped cross-section component
manufacturing apparatus illustrated in Fig. 7, at a stage at the start of processing.
Fig. 8B is a cross-section illustrating a stage at which the metal stock sheet is gripped
and restrained between a die and pad, and a holder and punch of the hat-shaped cross-section
component manufacturing apparatus illustrated in Fig. 7.
Fig. 8C is a cross-section illustrating a stage at which the punch has been pushed in
fi-om the stage illustrated in Fig. 8B.
Fig. 8D is a cross-section illustrating a state in which the punch has been pushed in
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further from the stage illustrated in Fig. 8C, such that the punch has been fully pushed in with
respect to the die.
Fig. 9A is a cross-section illustrating a mold to explain a defect that occurs when
removing a curving component from the mold after a punch has been fully pushed into a die
and a metal stock sheet has been formed into the curving component.
Fig. 9B is a cross-section illustrating the mold at a stage in which the punch is being
retracted from the die from the state illustrated in Fig. 9A.
Fig. 9C is a cross-section illustrating the mold at a stage in which the punch has been
fully retracted from the die from the state illustrated in Fig. 9B.
Fig. 1 OA is a cross-section illustrating a mold, in a state in which a punch has been
fully pushed into a die.
Fig. 1 OB is a cross-section illustrating the mold at a stage in which the punch is being
retracted from the die from the state illustrated in Fig. 1 OA.
Fig. 1 OC is a cross-section illustrating the mold at a stage in which the punch has
been fully retracted fi"om the die from the state illustrated in Fig. 1 OB.
Fig. llA is a cross-section illustrating a mold, in a state in which a punch has been
fully pushed into a die.
Fig. 11 B is a cross-section illustrating the mold at a stage in which the punch is being
retracted fi·om the die from the state illustrated in Fig. 11 A.
Fig. 11 C is a cross-section illustrating the mold at a stage in which the punch has
been fully retracted from the die from the state illustrated in Fig. II B.
Fig. 12A is a perspective view illustrating a pressure limiting device.
Fig. 12B is a perspective view illustrating a base plate to which a punch is fixed, and
floating blocks configuring a portion of a pressure limiting device.
Fig. 12C is a perspective view illustrating a blank holder.
Fig. 12D is a perspective view illustrating floating blocks incorporated into a blank
holder.
Fig. 12E is a partial plan view cross-section illustrating a location where a pressure
limiting device is provided in a hat-shaped cross-section component manufacturing apparatus.
Fig. 13A is an explanatmy diagram illustrating a cross-section of a hat-shaped
cross-section component manufacturing apparatus over time, as taken along line A-A in Fig.
12B, Fig. 12C, and Fig. 12E.
Fig. 13B is an explanatmy diagram illustrating a cross-section of a hat-shaped
cross-section component manufacturing apparatus over time, as taken along line A-A in Fig.
12B, Fig. 12C, and Fig. 12E, illustrating the cross-section at a later timing than in Fig. 13A.
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Fig. 13C is an explanatory diagram illustrating a cross-section of a hat-shaped
cross-section component manufacturing apparatus over time, as taken along line A-A in Fig.
12B, Fig. 12C, and Fig. 12E, illustrating the cross-section at a later timing than in Fig. 13B.
Fig. !3D is an explanatory diagram illustrating a cross-section of a hat-shaped
cross-section component manufacturing apparatus over time, as taken along line A-A in Fig.
12B, Fig. 12C, and Fig. 12E, illustrating the cross-section at a later timing thai1 in Fig. 13C.
Fig. 13E is an explanatory diagram illustrating a cross-section of a hat-shaped
cross-section component manufacturing apparatus over time, as taken along line A-A in Fig.
12B, Fig. 12C, and Fig. 12E, illustrating the cross-section at a later timing than in Fig. !3D.
Fig. 13F is an explanatory diagram illustrating a cross-section of a hat-shaped
cross-section component manufacturing apparatus over time, as taken along line A-A in Fig.
12B, Fig. 12C, and Fig. 12E, illustrating the cross-section at a later timing than in Fig. 13E.
Fig. 130 is an explanatory diagram illustrating a cross-section of a hat-shaped
cross-section component manufacturing apparatus over time, as taken along line A-A in Fig.
12B, Fig. 12C, and Fig. 12E, illustrating the cross-section at a later timing than in Fig. 13F.
Fig. 14 A is an explanatmy diagram illustrating a cross-section of a hat-shaped
__ cross-section component manufacturing appanlt1!£Jl.Yer time, as taken along line B-B in Fig.
12B, Fig. 12C, and Fig. 12E, illustrating the cross-section at the same timing as in Fig. 13A.
Fig. 14B is an explanatmy diagram illustrating a cross-section of a hat-shaped
cross-section component manufacturing apparatus over time, as taken along line B-B in Fig.
12B, Fig. 12C, and Fig. 12E, illustrating the cross-section at the same timing as in Fig. 13B.
Fig. 14C is an explanatory diagram illustrating a cross-section of a hat-shaped
cross-section component manufacturing apparatus over time, as taken along line B-B in Fig.
12B, Fig. 12C, and Fig. 12E, illustrating the cross-section at the same timing as in Fig. 13C.
Fig. 14 D is an explanatory diagram illustrating a cross-section of a hat -sh&ped
cross-section component manufacturing apparatus over time, as taken along line B-B in Fig.
12B, Fig. 12C, and Fig. 12E, illustrating the cross-section at the same timing as in Fig. 13D.
Fig. 14 E is an explanatory diagram illustrating a cross-section of a hat -shaped
cross-section component manufacturing apparatus over time, as taken along line B-B in Fig.
12B, Fig. 12C, and Fig. 12E, illustrating the cross-section at the same timing as in Fig. 13E.
Fig. 14F is an explanatory diagram illustrating a cross-section of a hat-shaped
cross-section component manufacturing apparatus over time, as taken along line B-B in Fig.
12B, Fig. 12C, and Fig. 12E, illustrating the cross-section at the same timing as in Fig. 13F.
Fig. 140 is an explanatory diagram illustrating a cross-section of a hat-shaped
cross-section component manufacturing apparatus over time, as taken along line B-B in Fig.
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12B, Fig. 12C, and Fig. 12E, illustrating the cross-section at the same timing as in Fig. 130.
fig. !SA is a perspective view illustrating a holding arm of another embodiment.
Fig. 15B is a perspective view illustrating floating blocks of another embodiment.
Fig. 16A is a side view illustrating a retention release section provided to the base
plate illustrated in Fig. 12B.
Fig. 16B is an explanatory diagram corresponding to Fig. !3D, illustrating a
cross-section of a hat -shaped cross-section component manufacturing apparatus including the
retention release section illustrated in Fig. 16A over time.
fig. 16C is an explanatory diagram corresponding to Fig. 13F, illustrating a
cross-section of a hat -shaped cross-section component manufacturing apparatus including the
retention release section illustrated in Fig. 16A over time.
Fig. 16D is an explanatory diagram corresponding to Fig. 130, illustrating a
cross-section of a hat-shaped cross-section component manufacturing apparatus including the
retention release section illustrated in Fig. 16A over time.
Fig. 17 A is a perspective view of a curving component, schematically illustrating
stress occurring in vertical walls.
Fig. 17B is a perspective view otlhe curving component, illustrating shear creasing
occurring in the vetiical walls.
Fig. 17C is a side view of the curving component, illustrating shear creasing
occurring in the vertical walls.
Fig. !SA is a cross-section of a hat-shaped cross-section component manufacturing
apparatus to explain the dimensions and the like of respective potiions in order to prevent the
occurrence of shear creasing.
Fig. ISB is a cross-section of a curving component to explain the dimensions and the
like of respective portions in order to prevent the occurrence of shear creasing.
Fig. ISC is a cross-section of a hat -shaped cross-section component manufacturing
apparatus to explain the dimensions and the like of respective portions in order to prevent the
occurrence of shear creasing.
Fig. lSD is cross-section of a curving component to explain the dimensions and the
like of respective portions in order to prevent the occurrence of shear creasing.
Fig. 19A is a perspective view of a curving component manufactured by the
hat-shaped cross-section component manufacturing apparatus illustrated in Fig. 5.
Fig. 19B is a plan view of the curving component illustrated in Fig. 19A, as viewed
from above.
Fig. 19C is a side view of the curving component illustrated in Fig. 19A.
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Fig. 190 is a fi·ont view of the curving component illustrated in Fig. 19A, as viewed
from one end portion.
Fig. 20 is a cross-section of a mold, illustrating the clearance b in Table 1.
DESCRIPTION OF EMBODIMENTS
[00 1 0] Explanation follows regarding a hat-shaped cross-section component manufacturing
apparatus and manufacturing method according to an exemplary embodiment of the present
invention. First, explanation follows regarding configuration of a hat-shaped cross-section
component, followed by explanation regarding the hat-shaped cross-section component
manufacturing apparatus and manufacturing method.
[00 11] Hat-Shaped Cross-Section Component Configuration
Fig. 1 A to Fig. 1 D and Fig. 2 illustrate a curving component 10, serving as a
hat -shaped cross-section component manufactured by drawing using a hat -shaped
cross-section component manufacturing apparatus 500 (see Fig. 5) of the present exemplary
embodiment. As illustrated in these drawings, the curving component I 0 includes a top
plate 11 extending along the length direction, and vertical walls 12a, 12b, that respectively
bend and extend from both shmt_end direction sides of the top plate 11 toward one sideiJLthe
thickness direction of the top plate 11. The curving component 10 further includes an
outward extending flange 13a that bends from an end of the vertical wall 12a on the opposite
side to the top plate II, and extends toward the side away from the vettical wall 12b, and an
outward extending flange 13b that bends at an end of the vertical wall 12b on the opposite
side to the top plate II, and extends toward the side away fi·om the vettical wall l 2a.
[0012] Ridge lines 14a, 14b are formed extending along the length direction of the curving
component 10 between the top plate II and the respective vertical walls 12a, 12b. Concave
lines 15a, 15b are formed extending along the length direction of the curving component 10
between the respective vertical walls 12a, 12b and outward extending flanges l3a, 13b.
[0013] The ridge lines 14a, l4b and the concave lines 15a, 15b are provided extending
substantially parallel to each other. Namely, the height of the vertical walls 12a, l2b from
the respective outward extending flanges 13a, 13b is substantially uniform along the length
direction of the curving component 10.
[0014] As illustrated in Fig. 2, a pmtion of the top plate 11 is formed with a convex shaped
curved portion lla that curves in an arc shape toward the outside of the lateral cross-section
profile of the hat shape, namely toward the outer surface side of the top plate II. Another
portion of the top plate II is formed with a concave shaped curved portion II b that curves in
an arc shape toward the inside of the lateral cross-section profile of the hat shape, namely
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toward the inner surface side of the top plate II. The ridge lines 14a, 14b formed by the top
plate II and the vertical walls 12a, 12b at the convex shaped curved portion II a and the
concave shaped curved portion II b are also curved in arc shapes at locations 16a, 16b, and
17a, 17b, corresponding to the convex shaped curved portion lla and the concave shaped
curved portion II b. Note that an "arc shape" is not limited to part of a perfect circle, and
may be pmt of another curved line, such as of an ellipse, a hyperbola, or a sine wave.
[0015] The curving component 10 described above is formed by forming a drawn panel301,
illustrated in Fig. 3B, by drawing a rectangular shaped metal stock sheet 20 I, serving as a
metal sheet, illustrated in Fig. 3A, and then trimming unwanted pmtions of the drawn panel
301.
[0016] Incidentally, when the curving component 10 with a hat-shaped cross-section is
manufactured by drawing, as illustrated in Fig. 4, excess material is present at a concave
shaped curved pmtion top plate 30la and a convex shaped curved portion flange 301 b of the
drawn panel 301 at the stage of forming the drawn panel 301, and creases are liable to occur.
Increasing restraint at the periphery of the metal stock sheet 20 I during the forming process
by, for example, raising the pressing force of a blank holder, or by adding locations for
forming draw beads to th~lank holder, thereby suppressing inflow of the mctalstock sheet
20 I into the blank holder, is known to be effective in suppressing the occurrence of creases.
[00 17] However, when there is increased suppression of inflow of the metal stock sheet 20 I
into the blank holder, there is a large reduction in the sheet thickness of the drawn panel301
at respective portions including a convex shaped curved pmtion top plate 30 I c, a concave
shaped curved pmtion flange 30ld, and both length direction end portions 30le, 30le. In
examples in which the metal stock sheet 20 I is a material with pmticularly low extensibility
(for example high tensile steel), it is conceivable that cracking could occur at these respective
portions.
[00 18] Accordingly, in order not to allow creasing and cracking in the manufacture of
curved components with a hat-shaped cross-section, such as front side members configuring
part of a vehicle body framework, by pressing using drawing, it has been difficult to employ
high strength materials with low extensibility as the metal stock sheet 201, meaning that low
strength materials with high extensibility have had to be employed.
[00 19] However, the occurrence of such creasing and cracking can be suppressed through a
curving component manufacturing process, described later, employing the hat-shaped
cross-section component manufacturing apparatus 500 of the present exemplary embodiment.
[0020] Hat-Shaped Cross-Section Component Manufttcturing Apparatus Configuration
Fig. 5 is an exploded perspective view of the hat-shaped cross-section component
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manufacturing apparatus 500 employed to manufacture a curving component 50 I, serving as
a hat-shaped cross-section component. Note that configuration of the curving component
501 is substantially the same as the configuration of the curving component 10 (see Fig. lA).
Fig. 6A is a cross-section illustrating the manufacturing apparatus illustrated in Fig. 5 at the
start of processing. Fig. 6B is a cross-section illustrating the manufacturing apparatus
illustrated in Fig. 5 at a stage at which a metal stock sheet 60 I is gripped and restrained
between a die 502 and pad 503, and a blank holder 505 and punch 504. Fig. 6C is a
cross-section illustrating a stage at which the punch 504 has been pushed in from the stage
illustrated in Fig. 6B. Fig. 60 is a cross-section illustrating a state in which the punch 504
has been pushed in nuiher from the stage illustrated in Fig. 6C, such that the punch 504 has
been fully pushed in with respect to the die 502.
[0021] As illustrated in Fig. 5, the hat-shaped cross-section component manufacturing
apparatus 500 includes the die 502 that has a shape including respective outer surface side
profiles of vertical walls 501a, 501b, and outward extending flanges 501d, 501e of the
curving component 501, the pad 503 that has a shape including the outer surface side profile
of a top plate 50 I c, the punch 504 that is disposed facing the die 502 and the pad 503 and that
has a shape including respective inner surface side profiles of the top plak501c and the
vertical walls 501a, 501b of the curving component 501, and the blank holder 505, serving as
a holder, with a shape including inner surface side profiles of the outward extending flanges
501d, 501e.
[0022] As illustrated in Fig. 6A to Fig. 60, the die 502 is disposed at an upper side of the
punch 504, and a central portion in the shmt direction (the left-right direction on the page) of
the die 502 is formed with an opening 502a opening toward the punch 504 side. Inner walls
of the opening 502a of the die 502 configure forming faces including the profile of the outer
surfaces of the vertical walls 50 Ia, 501b (see Fig. 5) of the curving component 501.
Moreover, end faces on the blank holder 505 side of both die 502 shmt direction side portions
configure forming faces including the profile of the faces on the vetiical wall 50 Ia, 501b sides
of the outward extending flanges 501d, 501e of the curving component 501 (see Fig. 5). A
pad press device 506, described later, is fixed to the closed end (upper end) of the opening
502a formed in the die 502. Moreover, the die 502 is coupled to a mover device 509 such as
a gas cushion, a hydraulic device, a spring, or an electric drive device. Actuating the mover
device 509 enables up-down direction movement of the die 502.
[0023] The pad 503 is disposed inside the opening 502a formed in the die 502. The pad
503 is coupled to the pad press device 506, this being a gas cushion, a hydraulic device, a
spring, an electric drive device, or the like. A face on the die 502 side of the pad 503
9
configures a forming face including the profile of the outer surface of the top plate SOle (see
Fig. 5) of the curving component 50 I. When the pad press device 506 is actuated, the pad
503 is pressed toward the punch 504 side, and a central portion 60la in the short direction (the
left-right direction on the page) of the metal stock sheet 60 I is pressed and gripped between
the pad 503 and the punch 504.
[0024] The punch 504 is formed by a protruding shape toward the pad 503 side at a location
in the lower mold that faces the pad 503 in the up-down direction. Blank holder press
devices 507, described later, are fixed at the sides of the punch 504. Outer faces of the
punch 504 configure forming faces including the profile of the inner surfaces of the vertical
walls SOla, 50lb and the top plate SOle (see Fig. 5) of the curving component 501.
[0025] The blank holder 505 is coupled to the blank holder press devices 507, serving as
holder press devices, these being gas cushions, hydraulic devices, springs, electric drive
devices, or the like. Die 502 side end faces of the blank holder 505 configure forming faces
including the profile of faces of the outward extending flanges SOld, SOle of the curving
component SOl on the opposite side to the vetiical walls SOla, SO!b (see Fig. S). When the
blank holder press devices S07 are actuated, the blank holder SOS is pressed toward the die
S02_sisL~~and both short direction side potiions 60 I b, 60 I c of thunetal stock sheet 60 I are
pressed and gripped.
[0026] Next, explanation follows regarding a pressing process of the metal stock sheet 601
by the hat-shaped cross-section component manufacturing apparatus SOO described above.
[0027] First, as illustrated in Fig. 6A, the metal stock sheet 60 I is disposed between the die
S02 and pad S03, and the punch S04 and blank holder S05.
[0028] Next, as illustrated in Fig. 6B, the central portion 60la of the metal stock sheet 601,
namely a portion of the metal stock sheet 601 that will form the top plate SOle (see Fig. 5), is
pressed against the punch 504 by the pad 503, and pressed and gripped between the two.
Both side portions 60lb, 60lc of the metal stock sheet 601, namely respective portions of the
metal stock sheet 601 that will form the vetiical walls SOla, SOlb and the outward extending
flanges SOld, SOle (see Fig. 5), are pressed against the die 502 by the blank holder 505, and
are pressed and gripped between the two.
[0029] The pad press device 506 and the blank holder press devices S07 are actuated, such
that the central portion 60 I a and both side portions 60 I b, 60 I c of the metal stock sheet 60 I
are pressed with a specific pressing force and gripped. The central pmiion 60 I a and both
side pmiions 601b, 60lc of the metal stock sheet 601 are formed into curved profiles to
follow the curved profiles of the pressing curved faces as a result.
[0030] In this state, the mover device S09 is actuated, and the blank holder 505 and the die
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502 arc moved relatively in a direction away from the die 502 toward the blank holder 505
(toward the lower side), thereby forming the curving component 501. The pad press device
506 and the blank holder press devices 507 retract in the up-down direction accompanying
lowering of the die 502. When the pad press device 506 and the blank holder press devices
507 retract in the up-down direction, the central portion60la and both side portions 601 b,
601c of the metal stock sheet 601 are pressed with a specific pressing force.
[0031] As illustrated in Fig. 6C, the metal stock sheet 60 I gripped between the die 502 and
the blank holder 505 flows into the opening 502a between the punch 504 and the blank holder
505 accompanying the movement of the blank holder 505 and the die 502, thereby forming
the vertical walls SOla, 50lb (see Fig. 5).
[0032] Then, as illustrated in Fig. 6D, the blank holder 505 and the die 502 move by a
specific distance, and forming is completed at the point when the height of the vertical walls
50 Ia, 50 I b reaches a specific height.
[00.3 3] Note that in the example illustrated in Fig. 6A to Fig. 6D, the curving component 50 I .
is formed by moving the blank holder 505 and the die 502 in a stationary state of the punch
504 and the pad 503. However, the present invention is not limited thereto, and the curving
__ component 50 I may be formed in the following manner._
[0034] Fig. 7 illustrates a hat-shaped cross-section component manufacturing apparatus 600
according to another exemplary embodiment for manufacturing the curving component 50 I.
Fig. 8A is a cross-section illustrating the manufacturing apparatus illustrated in Fig. 7 at a
stage at the stmi of processing. Fig. 8B is a cross-section illustrating a stage at which the
metal stock sheet 601 is gripped and restrained between a die 602 and pad 603, and a blank
. holder 605 and punch 604 of the manufacturing apparatus illustrated in Fig. 7. Fig. 8C is a
cross-section illustrating a stage at which the punch 604 has been pushed in fi·om the stage
illustrated in Fig. 8B. Fig. 8D is a cross-section illustrating a state in which the punch 704
has been pushed in fmiher fi·om the stage illustrated in Fig. 8C, such that the punch 604 has
been fi.Jlly pushed in with respect to the die 602.
[0035] In contrast to the hat-shaped cross-section component manufacturing apparatus 500
illustrated in Fig. 5 and Fig. 6A to Fig. 6D, in the hat-shaped cross-section component
manufacturing apparatus 600 the blank holder 605 and the punch 604 are provided at an upper
side of the die 602 and the pad 603. In the hat-shaped cross-section component
manufacturing apparatus 600, the curving component 501 is formed by moving (lowering) the
pad 603 and the punch 604 in a state in which the die 602 is fixed, and the blank holder 605
presses the metal stock sheet 60 I against the die 602 without moving. Note that in both the
hat-shaped cross-section component manufacturing apparatus 600 and the hat-shaped
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cross-section component manufacturing apparatus 500, the relative movement within the
mold is the same, and the metal stock sheet 601 can be formed into the curving component
501 by using whichever of the hat-shaped cross-section component manufacturing
apparatuses 500, 600.
[0036] Next, explanation follows regarding a removal process of the curving component 501
from the hat-shaped cross-section component manufacturing apparatus 500 (mold) after
pressing the metal stock sheet 601, namely after forming the curving component 501.
[0037] As illustrated in Fig. 9A to Fig. 9C, when the curving component 501 is dcmolded
from the hat-shaped cross-section component manufacturing apparatus 500 (mold), it is
necessary to move the die 502 upward from the state in Fig. 6D and away from the punch,
504 to create a gap within the mold. When this is performed, as illustrated in Fig. 9B and
Fig. 9C, while the pad 503 and the blank holder 505 arc being pressed by the respective pad
press device 506 and the blank holder press devices 507, the curving component 501 bears ·
pressing force directed in mutually opposing directions from the pad 503 and the blank holder
505 during demolding, deforming and crushing the curving component 501 by the pressing
forces directed in opposite directions, as illustrated in Fig. 9C.
[0038] Accordingly, as illustrated in Fig. I OA to Fig. IOC, after the metal stock sheet 601
has been formed into the curving component 50 I, configuration is made such that the die 502
and the pad press device 506 are separated from the blank holder 505 in a state in which the
blank holder 505 does not move relative to the punch 504, and the blank holder 505 does not
press the formed curving component against the die 502. Accordingly, although the pad
press device 503 presses the curving component until the pad press device 506 has extended
to the end of its stroke, after the pad press device 506 has moved a specific distance or greater
and the pad press device 506 has fully extended to the end of its stroke, the pad 503 is
separated from the punch 504. The curving component 501 therefore does not bear pressing
from the pad 503 and the blank holder 505 at the same time, and the die 502 and the pad 503
can be separated from the blank holder 505 and the punch 504, thereby enabling the curving
component 50 I to be removed from the mold without being deformed.
[0039] As another exemplary embodiment, as illustrated in Fig. I lA to Fig. I 1 C, after
forming the metal stock sheet into the curving component 501, the pad 503 is not moved
relative to the die 502, and the pad 503 does not press the formed curving component 501
against the punch 504. In this state, when the pad 503 and the die 502 are separated from the
blank holder 505 and the punch 504, the blank holder 505 press the curving component until
the blank holder press devices 507 extend to the end of their stroke. The blank holder 505 is
then separated from the die 502 after the die 502 has moved a specific distance or greater and
12
the blank holder press devices 507 have fully extended to the end of their stroke. This
thereby enables the die 502 and pad 503, and the blank holder 505 and punch 504, to be
separated without the curving component 50 I bearing pressure from the pad 503 and the
blank holder 505 at the same time, thereby enabling the curving component 501 to be
removed from the mold.
[0040] Yet another exemplary embodiment is one in which, although not illustrated in the
drawings, after forming the metal stock sheet into the curving component 50 I, the pad 503
does not move relative to the blank holder 505, and the pad 503 does not press the formed
curving component against the punch 504. In this state, when the pad 503, die 502, and
blank holder 505 are separated from the punch 504, the blank holder 505 presses the curving
component 501 until the blank holder press devices 507 have extended to the end of their
strokes. After the die 502 moves a specific distance or greater and the blank holder press
devices 507 have fully extended to the end of their stroke, the blank holder 505 is then
separated from the die 502. This thereby enables the die 502 and pad 503 to be separated,
from the blank holder 505 and punch 504, without the curving component 50 I bearing
pressure from the pad 503 and the blank holder 505 at the same time, thereby enabling the
curving component 50 I to be rem_QYe_dfi'om the mold.
[0041] Accordingly, in order to prevent damage to the curving component 501 during
demolding, the hat -shaped cross-section component manufacturing apparatus 500 may be
provided with a pressure limiting device capable of preventing the curving component 50 I
from bearing pressure from the pad 503 and the blank holder 505 at the same time.
[0042] Explanation follows regarding a specific configuration of a pressure limiting device
provided to the hat-shaped cross-section component manufacturing apparatus 500.
[0043] Pressure Limiting Device 510 Configuration
As illustrated in Fig. 12A, the pressure limiting device 510 includes floating blocks
514 that are formed in rectangular block shapes, and serve as a pressure limiting section.
The pressure limiting device 510 further includes a pair of holding arms 511, serving as a
retention section, that engage with the floating blocks 514 when forming of the curving
component 501 is completed, thereby integrating the floating blocks 514 together with the
blank holder 505, namely, enabling the floating blocks 514 to move as a unit with the blank
holder 505. The pressure limiting device 510 further includes a retention release section 515
that releases retention of the floating blocks 514 by the holding arms 511.
[0044] As illustrated in Fig. 12B, two of the floating blocks 514 are provided on a base plate
508. Note that in the present exemplary embodiment, explanation is given regarding a case
in which two of the floating blocks 514 are employed; however, a single floating block may
13
be employed depending on the shape and dimensions of the curving component 501 to be
formed, or three or more floating blocks may be employed in cases in which there is a large
pad load.
[0045] The two floating blocks 5 I 4 are formed using a block shaped steel material having a
rigidity and strength so as not to buckle or plastically deform even when bearing the pressing
force of the pad 503. The two floating blocks 514 are respectively disposed on the base
plate 508 on both length direction sides of the punch 504, and are capable of ascending and
descending. As illustrated in Fig. 12A, a location on an upper side of each floating block
514 configures a block upper portion 514a with a width dimension that is a substantially
uniform dimension as viewed from the side, and a location on a lower side of each floating
block 514 configures a block lower portion 514b that, as viewed from the side, has a width
dimension that is a dimension of the width dimension of the block upper potiion 514a or
greater, and that is formed such that its width dimension gradually narrows on progression
toward the upper side. The retention release section 515, described later, is provided to the
block upper potiion 514a. As illustrated in Fig. 12C, Fig. 12D, and Fig. 12E, both length
direction end potiions of the blank holder 505 are formed with block upper portion insertion
holes 505a thmugh which__the_block upper portions 514a pass. As illustrated in_Fig. J2A, a
lower end potiion of the block lower potiion 514b is formed with recess shaped engaged-with
portions 514c with which engagement portions 51lc of the holding arms 511, described later,
engage.
[0046] As illustrated in Fig. 12A and Fig. 12D, the pair of holding arms 511 are disposed
inside holding arm housing holes 505b formed integrally to the block upper portion inse1iion
holes 505a. Moreover, the pair of holding arms 511 each include a swinging block 51la
formed in a block shape with its length direction in the up-down direction as viewed fmm the
side, and a rod shaped extension portion 51lb extending from the swinging block 51la toward
the upper side. A lower end portion of each swinging block 511 a is configured by a hook
shaped engagement portion 511c that engages with the engaged-with potiion 514c formed to
the block lower portion 514b of the floating block 514. An upper portion of the swinging
block 511 a is suppmied by the blank holder 505 through a pin 516, so as to be capable of
swmgmg.
[0047] At the forming bottom dead center, namely, on completion offonning the curving
component 501 (see Fig. 6D), the swinging blocks 51la swing toward one side (swing in the
direction of the arrows C1) as illustrated in Fig. 12A, such that the engagement pmiions 511 c
of the swinging blocks 511a engage with the engaged-with portions 514c of the floating block
514. As illustrated in Fig. 12D, this thereby enables the floating block 514 to move together
14
as a unit with the blank holder 505. Moreover, as illustrated in Fig. 12A, in the present
exemplary embodiment, a pair of springs 512 to which rollers 513 are attached are fixed to
the base plate 508 (see Fig. 12B). At the forming bottom dead center, the pair of springs 152
press the swinging blocks 511 a of the holding arms 511 through the rollers 513, such that the
swinging blocks 511a swing toward the one side (swing in the arrow Cl direction), and the
engagement portions 511 c of the swinging blocks 511a engage with the engaged-with
portions 514c of the floating block 514. Part of the pad 503 is in contact with an upper end
portion of the floating block 514 as the floating block 514 ascends together with the blank
holder 505. Accordingly, movement of the pad 503 and the punch 504 in approaching
directions is prevented by the pressure limiting device 510, and, during demolding, either the
formed curving component 501 (see Fig. 60) is not pressed between the pad 503 and the
blank holder 505, or only a small amount of pressure acts thereon.
[0048] From the state illustrated in Fig. 12A, the swinging blocks 5 I Ia then swing toward
another side (swing in the direction of the arrows C2), thereby releasing the engagement
between the engagement pmiions 511c of the swinging blocks 51 !a and the engaged-with
portions 514c of the floating block 514. In the present exemplary embodiment, pati of the
retention release_s_e_ction 515, described later, presses the extension portions 51 I b of the
holding arms 511, such that the swinging blocks 511 a swing toward the another side (swing in
the direction of the arrows C2), thereby releasing the engagement between the engagement
portions 511c of the swinging blocks 5lla and the engaged-with portions 514c of the floating
block 514.
(0049] The retention release sectionS IS includes a tilt plate 518. The tilt plate 518 is
disposed inside an opening 514d that opens onto a side of the block upper portion514a, and is
supported at intermediate pmiions by pins 517, so as to be capable of tilting. At an upper
side of the tilt plate 518, a pad load transmission rod 519 is provided disposed inside an
opening 514e that places an upper end of the block upper portion514a in communication with
the opening 514d. A coil spring 520 is provided at a lower side of the tilt plate 518.
[0050] One end portion 518a of the tilt plate 518 projects out from the floating block 514
toward the side, and the one end pmiion518a of the tilt plate 518 is disposed at an upper side
of the extension portions 5 I 1 b of the holding arms 5 I I when the floating blocks 514 and the
blank holder 505 are in an integrated state, as illustrated in Fig. 12A and Fig. 120.
[0051] The pad load transmission rod 519 is disposed at an upper side of another end portion
518b of the tilt plate 518. The pad load transmission rod 519 is pressed toward the lower
side by the pad 503, such that the pad load transmission rod 519 presses the other end portion
518b of the tilt plate 518. Accordingly, in a state in which the pad 503 contacts an upper end
IS
portion of the block upper portion 514a, the one end portion 518a of the tilt plate 518 moves
away from the extension portions 51! b of the holding arms 511. The holding arms 511 arc
then able to swing in the arrow Cl directions, enabling, as illustrated in Fig. 12A, the
engagement portions 511 c of the holding arms 511 to engage with the engaged-with portions
514c of the floating block 514.
[0052] The coil spring 520 is disposed at a lower side of the other end portion 518b ofthe
tilt plate 518, and the coil spring 520 biases the other end pmtion 518b of the tilt plate 518
toward the upper side. Accordingly, in a state in which the pad 503 has moved away from
the upper end portion of the block upper portion 514a, the one end portion 518a of the tilt
plate 518 tilts toward the side of the extension portions 511 b of the holding arms 511, and the
one end portion 518a of the tilt plate 518 presses the extension portions 511 b of the holding
arms 511. Accordingly, the swinging blocks 511 a swing in the arrow C2 directions against
the pressing force of the rollers 513 from the springs 512, releasing the engagement between
the engagement portions 511c of the swinging blocks 511a and the engaged-with portions
514c of the floating block 514. Namely, retention of the floating block 514 by the holding
arms 511 is released.
[0053]___Next, explanation follows regarding operation of the pLeBsure limiting device 510.
[0054] Fig. 13A and Fig. 14A illustrate a state of the curving component 501 prior to the
sta11 of forming. At the timing illustrated in Fig. 13B and Fig. 14B, the metal stock sheet
601 is gripped by the pad 503 and punch 504, and the die 502 and blank holder 505. Note
that in the present exemplary embodiment, adjustment blocks 521 are interposed between the
pad 503 and the floating blocks 514. Clearance is thereby adjusted according to variations in
sheet thickness of the metal stock sheet 601 and the like. In the present exemplary
embodiment, respective adjustment blocks 521 are fixed to both length direction end portions
of the pad 503. In the following explanation, contact between the adjustment blocks 521 and
the floating blocks 514 includes cases in which the pad 503 contacts the floating blocks 514
directly. Moreover, at the timing illustrated in Fig. 13B and Fig. 14B, both length direction
end portions of the pad 503 are in contact with the upper end portions of the floating blocks
514 tlu-ough the adjustment blocks 521.
[0055] At the timing illustrated in Fig. 13C and Fig. 14C, the metal stock sheet 601 gripped
between the die 502 and the blank holder 505 flows into the opening 502a between the punch
504 and the die 502, and the ve11ical walls 50 I a, 501 b of the curving component 501 is
formed, as the blank holder 505 and the die 502 move toward the lower side. Then, at the
timing illustrated in Fig. 130 and Fig. 140, the blank holder 505 and the die 502 move to the
forming bottom dead center, and forming of the curving component 501 is completed. In
16
this state, both length direction end portions of the pad 503 are in contact with the upper end
portions of the floating blocks 514 through the adjustment blocks 521.
[0056] When the blank holder 505 has moved to the forming bottom dead center, the
adjustment blocks 521 press down the tops of the pad load transmission rods 519 in the arrow
Z direction, as illustrated in Fig. 12A, such that the one end portion 518a of each tilt plate 518
separates from the extension portions 511 b of the holding arms 511, and the engagement
portions 511c of the holding arms 511 engage with the engaged-with portions 514c of the
floating blocks 514 under the biasing force of the springs 512. The blank holder 505 is
thereby coupled together with the floating blocks 514, and in the subsequent demolding
process, the blank holder 505 and the floating blocks 514 ascend together as a unit.
[0057] After reaching the forming bottom dead center, as illustrated in Fig. 13E and Fig. 13F,
and in Fig. 14E and Fig. 14F, when the blank holder 505 ascends together with the floating
blocks 514, the top plate 50lc of the curving component 501 that was hithetto in contact with
an upper face of the punch 504 separates from the upper face of the punch 504. When the
blank holder 505 is ascending together with the floating block 514, the floating blocks 514 are
coupled to the blank holder 505 through the holding arms 511, and the pad 503 and the blank
holder 505 are prevented from moving relative to each_other in approaching directions along
the up-down direction. During the demolding process, even if the formed curving
component 50 I bears force along the approaching directions of the pad press device 506 and
the blank holder press devices 507 (see Fig. 118) due to the force thereof, the formed curving
component 501 is not pressed between the pad 503 and the blank holder 505 to such an extent
that it is deformed.
[0058] As illustrated in Fig. 130·and Fig. 140, the curving component 501 can be removed
when the die 502 ascends to its top dead center. When the die 502 reaches the top dead
center, and the pad 503 separates from the floating blocks 514, namely when the adjustment
blocks 521 attached to the pad 503 separate from the floating blocks 514, as illustrated in Fig.
12D, the one end portion 518a of each tilt plate 518 presses the extension pmtions 511 b of the
holding arms 511 under the biasing force of the coil spring 520. Accordingly, the swinging
blocks 5lla swing in the arrow C2 directions, and the engagement between the engagement
portions 5llc of the swinging blocks 5lla and the engaged-with portions 514c of the floating
block 514 is released. Then, as illustrated in Fig. 130, the floating blocks 514 drop through
the block upper portion insettion holes 505a and the holding ani1 housing holes 505b (see Fig.
12C), and return to their home positions on the base plate 508 (see Fig. 128).
[0059] As described above, in the present exemplary embodiment, employing !he hat-shaped
cross-section component manufacturing apparatus 500 provided with the pressure limiting
17
device 5 I 0 enables the formed curving component 50 I to be demolded without sustaining
damage. The hat-shaped cross-section component manufacturing apparatus 500 of the
present exemplary embodiment moreover enables the curving component 501 to be demolded
without any increase in cycle time compared to conventional manufacturing apparatus that is
not provided with the pressure limiting device 5IO described above. This thereby enables
low cost mass production of the curving component 501.
[0060] In the present exemplary embodiment, explanation has been given regarding an
example in which the floating blocks 514 and the blank holder 505 are configured capable of
moving together as a unit by employing the holding arms 5 I I. However, the present
invention is not limited thereto. Namely, other mechanisms may similarly be applied as long
as they are mechanisms capable of retaining the floating blocks 514 at the forming bottom
dead center, and of separating the floating blocks 514 after the pad has separated from the two
floating blocks 514. Examples of such configurations include:
(I) Latch types (types in which latch anns are provided to the floating blocks 514);
(2) Push pin types (methods in which sprung pins enter fixing holes from the
floating blocks 514 or the blank holder 505 and form a unit therewith);
(3) Gear types_ (gears installed in theJ1oating blocks 514 are retained by pressing
by the pad 503, and lock with gears installed to the blank holder 505); and
( 4) Cam types (installed with a cam that moves horizontally accompanying
downward movement of the blank holder 505, such that a leading end of the cam locks the
floating block 514 ).
[0061] In the present exemplary embodiment, explanation has been given regarding an
example in which the hook shaped engagement pmtions 511 c formed to the swinging blocks
511a of the holding arms 511 engage with the engaged-with portions 514c formed to the block
lower portion 514b of each floating block 514; however, the present invention is not limited
thereto. For example, as illustrated in Fig. !SA and Fig. 15B, engagement recesses 5lld,
serving as engagement pmtions formed to the swinging blocks 511a of the holding arms 511,
may engage with engagement protrusions 514f, serving as engaged-with portions, formed to
the block lower portion 514b of each floating block 5 I 4.
[0062] In the present exemplary embodiment, explanation has been given regarding an
example in which the retention release section 515 is provided to the block upper portion
514a of each floating block 514. However, the present invention is not limited thereto. For
example, as illustrated in Fig. 16A, a retention release section 522 having the same fimction
as the retention release section 5 I 5 described above may be provided to frame portions 508a
(see also Fig. 12B) so as to extend up from both length direction end portions of the base plate
18
508, serving as a base section. Each retention release section 522 is configured including a
tilting portion 524 that is tiltably supported by the frame portion 508a of the base plate 508
through a bracket 523, and a coil spring 525 that biases a leading end side 524a of the tilting
portion 524 toward the lower side. In the retention release section 522, when the blank
holder 505 and the die 502 have risen a specific distance from the forming bottom dead center
illustrated in Fig. I 6B, the extension portions 5 I I b of the holding arms 511 contact the
leading end side 524a of the tilting portion 524, and the extension portions 5 I I b of the
holding arms 51! are pressed toward the lower side by the leading end side 524a of the tilting
portion 524. Accordingly, as illustrated in Fig. 16C and Fig. 16D, the engagement between
the engagement pmiions 5 I I c of the swinging blocks 5 I! a and the engaged-with portions
514e of the floating block 514 is released.
[0063] In the present exemplary embodiment, explanation has been given regarding an
example in which the formed curving component 501 is suppressed from being pressed
between the pad 503 and the blank holder 505 by pmi of the pad 503 contacting the upper end
portion of the floating blocks 514 through the adjustment blocks 521; however, the present
invention is not limited thereto. For example, the formed curving component 501 may be
suppressed Jimn being pressed between_1:lli:_pad 503 and the blank holder 505 by a member
that moves together with the pad 503 contacting the upper end pmiion of the floating block
514.
[0064] Operation and Advantageous Effects of Present Exemplmy Embodiment, Suitable
Vi'dues etc. for Various Parameters
Next, explanation follows regarding operation and advantageous effects of the
present exemplary embodiment, and suitable values for various parameters, and the like.
[0065] As illustrated in Fig. 12A to Fig. 14G, in the present exemplary embodiment, the
hat-shaped cross-section component manufacturing apparatus 500 is provided with the
pressure limiting device 510 described above. During demolding, the curving component
501 can be removed from the mold (the blank holder 505, the die 502, the punch 504, and the
pad 503) in a state in which the formed curving component 501 is prevented by the pressure
limiting device 510 from being pressed by the pad 503 and the blank holder 505 at the same
time.
[0066] In the present exemplary embodiment, during formation of the vertical walls 50 Ia,
501 b of the curving component 50 I by the hat-shaped cross-section component
manufacturing apparatus 500 illustrated in Fig. 5 to Fig. 6D, the portion of the metal stock
sheet 60 I that will form the top plate 50 I c is pressed and gripped by the pad 503 and the
punch 504. Provided that the pressing force is sufficient, the portion of the metal stock sheet
19
60 I that will form the top plate 50 I c cannot be deformed in its thickness direction during the
fanning process, enabling the occurrence of creases at this portion to be suppressed.
Moreover, the pm1ions of the metal stock sheet 601 that will form the outward extending
flanges SOld, SOle are also pressed and gripped by the blank holder 505 and the die 502, such
that provided that the pressing force is sufficient, the pm1ions of the metal stock sheet 60 I that
will form the outward extending flanges SOld, SOle cannot be deformed in the thickness
direction, enabling the occurrence of creases at these portions to be suppressed.
[0067] However, if the above pressing forces are insufficient, deformation of the metal stock
sheet 60 I in the thickness direction cannot be prevented, and creases will occur at the portion
of the metal stock sheet 601 that will form the top plate SOle and at the portions of the metal
stock sheet 601 that will form the outward extending flanges SOld, SOle. The sheet
thickness employed in structural members configuring automotive vehicle body framework
(such as front side members) is generally fi·om 0.8 nun to 3.2 mm. When a steel sheet with
tensile strength of from 200 MPa to 1600 MPa is formed by using the hat-shaped
cross-section component manufacturing apparatus 500 illustrated in Fig. 5 to Fig. 6D, the
above pressing forces are preferably 0.1 MPa or greater.
[0068] _Fig. I 7 A illustratesstress_arising in the vertical walls SOia, 501 b of the curving__
component 501. Fig. I 7B and Fig. 17C illustrate shear creasing arising in the vertical walls
SOla, 501b of the curving component 501.
[0069] In Fig. 17 A, it can be seen that deformation of the portions of the metal stock sheet
601 that will form the vet1ical walls SOia, 50lb from before to after forming the vct1ical walls
SOla, 501 b ofthe curving component 501 is mainly shear deformation. Forming the vertical
walls SOia, 50Ib of the curving component 501 accompanied by deformation that is mainly
shear deformation suppresses a reduction in the sheet thickness of the vertical walls SOia,
501 b compared to the sheet thickness of the metal stock sheet 601. This thereby enables the
occtmence of creasing and cracking in the vertical walls 50 I a, 50 I b to be suppressed.
[0070] During formation of the vertical walls SOla, 50Ib, the portions of the metal stock
sheet 601 that will form the vertical walls SOia, 50Ib undergo compression deformation in the
minimum principal strain direction of the shear deformation. Accordingly, as illustrated in
Fig. 17B and Fig. 17C, shearcreasingWoccurs in the vertical walls SOla, 50Ib ofthe
curving component 501 if the clearance between the die 602 and the punch 604 becomes large.
In order to suppress such shear creasing W, it is effective to reduce the clearance between the
die 602 and the punch 604 such that the clearance is brought close to the sheet thickness of
the metal.stock sheet 601 during formation of the vertical walls 50 Ia, 501 b.
[0071] As illustrated in Fig. I SA to Fig. 18D, it is necessary for an internal angle 8 formed
20
between the respective vertical walls 50 I a, 50 l b and the top plate 50 l c to be 90° or greater so
as not to have a negative mold angle during forming. However, since the clearance during
initial forming increases if too far over 90°, an angle close to 90° that is 90° or greater is
advantageous. When a steel sheet with a sheet thickness of from 0.8 mm to 3.2 mm, and
tensile strength of from 200 MPa to 1600 MPa, that is generally employed in structural
members configuring automotive vehicle body framework, is used to form a component in
which the height of the vertical walls SOla, 50lb is 200 nun or less, the internal angle formed
between the top plate SOle and the vertical walls SOla, 50lb is preferably from 90° to 92°,
and a clearance b between the die 502 and the punch 504 at the portions forming the vertical
walls SOla, 50lb at the point when forming of the vertical walls SOla, 50lb is completed is
preferably from 100% to 120% of the sheet thickness of the metal stock sheet 601.
[0072] Next, explanation follows regarding results of investigation into the occurrence of
creasing in the curving component 501, using parameters of (1) the angle formed between the
vertical walls SOla, 50lb and the top plate SOle, (2) mold clearance (varying the sheet
thickness t with respect to the fixed clearance b), (3) the pressure applied to the pad 503 (pad
pressure), ( 4) the pressure applied to the blank holder 505 (holder pressure), and (5) the
tensile strength of the..material.
[0073] Fig. 19A is a perspective view illustrating the curving component 501. Fig. 198 is a
plan view illustrating the curving component 501 in Fig. 19A, as viewed from above. Fig.
19C is a side view of the curving component 501 in Fig. 19A. Fig. 19D is a cross-section
illustrating a cross-section of the curving component 501 taken along the line A-A in Fig. 19C.
Fig. 20 is a cross-section of the mold.
21
[0074]
Table 1
Example
CASE
I
2
3
4
5
6
7
8
9
10
II
12
13
14
15
16
17
18
19
Tensile
Strength of
Material
(MPa)
980
980
980
980
980
980
980
980
980
440
440
440
400
440
440
440
1310
590
440
Sheet e Clearance
Thickness t b
(mm) COl (mm)
1.8 90 1.8
1.8 91 1.8
1.8 92 1.8
1.8 95 1.8
1.8 80 1.8
1.6 90 1.8
1.4 90 1.8
1.2 90 1.8
1.0 90 1.8
1.6 90 1.8
1.6 90 1.8
1.6 90 1.8
1.6 90 1.8
1.6 90 1.8
1.6 90 1.8
1.6 90 1.8
1.8 90 1.8
1.6 90 1.8
1.6 90 1.8
-
IIJE
bit Pad Blank Creasing
Pressure Holder
Pressure
I (MPa) (MPa)
1.00 5.83 2.50 Absent
1.00 5.83 2.50 Absent
1.00 5.83 2.50 Absent
1.00 5.83 2.50 Somewhat present
1.00 5.83 2.50 Somewhat present
1.13 5.83 2.50 Absent
1.29 5.83 2.50 Somewhat present
1.50 5.83 2.50 Somewhat present
1.80 5.83 2.50 Somewhat present
1.13 2.33 1.50 Absent
1.13 1.17 !.50 Absent
1.13 0.58 1.50 Absent
i up 0.09 1.50 Somewhat present
l.b 3.50 1.00 Absent
1.13 3.50 0.75 Absent
1.13 3.50 0.09 Somewhat present
1.00 5.83 2.50 Absent
1.13 3.50 1.50 Absent
1.13 2.33 1.50 Absent
..
22
[0075] The angle 8 in Table I is the internal angle 8 formed between the vertical walls SOla,
50 l b and the top plate 501 c, as illustrated in Fig. 190. The clearance b in Table 1 is the gap
between the pad 503 and the punch 504, between the die 502 and punch 504, and the die 502
and blank holder 505, as illustrated in Fig. 20.
[0076] Each of the Examples 1 to 19 in Table 1 are examples of the present exemplary
embodiment. In Table l, "somewhat present" refers to the occurrence of creasing at an
acceptable level. (I) Nos. 1 to 5 examples of cases in which the angle formed between the
vertical walls SOla, 501b and the top plate SOle was varied. (2) Nos.~ to 9 are examples of
cases in which the mold clearance, more specifically the sheet thickness t with respect to a
fixed clearance b, was varied. (3) Nos. 10 to 13 are examples of cases in which the pressure
applied to the pad 503 (pad pressure) was varied. (4) Nos. 14 to 16 are examples of cases in
which the pressure applied to the blank holder 505 (holder pressure) was varied. (5) Nos. 17
to 19 are examples of cases in which the tensile strength of the material was varied. The
presence or absence of creasing occurrence was investigated in curving components
manufactured for each Example.
[0077] It can be seen from the above table that unacceptable creasing of the components did
not occur in_the_curving component 501 within the range ofparametexs investigated.
[0078] Explanation has been given above regarding examples in which curving hat-shaped
cross-section components (the curving component 501) are formed using the hat-shaped
cross-section component manufacturing apparatus 500 (see Fig. 5). However, the present
invention is not limited thereto. For example, the hat-shaped cross-section component
manufacturing apparatus 500 may be used to form hat-shaped cross-section components that
have a uniform cross-section along the length direction, and do not curve in side view or in
plan view.
[0079] Explanation has been given regarding exemplary embodiments of the present
invention; however, the present invention is not limited to the above, and obviously various
modifications other than the above may be implemented.
[0080] The entire content of Japanese Patent Application No. 2013-221522, filed on October
24,2013, is incorporated by reference in the present specification.
23

CLAIMS
I. A hat-shaped cross-section component manufacturing apparatus comprising:
a die that includes a forming face that presses both side portions of a metal sheet, and
that includes an opening;
a punch that is disposed facing the opening of the die, wherein the punch is disposed
inside the opening when a mold is closed, and wherein the punch includes a forming face that
presses a central portion of the metal sheet;
a pad that is disposed inside the opening formed in the die, wherein the pad includes
a forming face that presses and grips the central portion of the metal sheet against the punch
when the mold is closed so as to configure a forming face corresponding to the forming face
of the punch;
a holder that is disposed facing the die, wherein the holder includes a forming face
that presses and grips both side portions of the metal sheet against the die when the mold is
closed so as to configure a forming face corresponding to the forming face of the die; and
a pressure limiting device that includes a pressure limiting section that moves
toge!lleLwith the holder during demolding after forming a hllt=sJmped cross-section
component with a hat shaped cross-section, wherein the pressure limiting device is interposed
between the pad and the holder, and wherein the pressure limits pressing on the hat -shaped
cross-section component by the pad and the holder.
2. The hat-shaped cross-section component manufacturing apparatus of claim I, wherein the
pressure limiting device includes a retention release section that enables movement of the
pressure limiting section relative to the holder once the holder has moved a specific distance.
3. The hat -shaped cross-section component manufacturing apparatus of claim I or claim 2,
wherein the pressure limiting device includes a retention section that is provided at the holder,
that engages with the pressure limiting section when forming of the hat-shaped cross-section
component is completed, and that is released from engagement with the pressure limiting
section after the pad has separated from the pressure limiting section.
4. The hat-shaped cross-section component manufacturing apparatus of claim3, wherein:
the retention section is supported on the holder so as to be capable of swinging;
the retention section engages with the pressure limiting section by the retention
section swinging toward one side; and
24
the engagement between the retention section and the pressure limiting section is
released by the retention section swinging toward another side.
5. The hat-shaped cross-section component manufacturing apparatus of any one of claim 2,
claim 3 when dependent from claim 2, or claim 4 when dependent from claim 2, wherein the
retention release section releases the engagement between the retention section and the
pressure limiting section by contacting the retention section.
6. The hat-shaped cross-section component manufacturing apparatus of claim 2, or any one
of claim 3 to claim 5 when dependent from claim 2, wherein the retention release section is
integrally provided at the pressure limiting section.
7. The hat-shaped cross-section component manufacturing apparatus of claim 2, or any one
of claim 3 to claim 5 when dependent from claim 2, wherein the retention release section is
provided at a base member to which the punch is fixed.
_____ lL A hat-shaped cross-section component manufacJ.uring method employing the hat-shaped
cross-section component manufach1ring apparatus of any one of claim I to claim 7, the
hat-shaped cross-section component manufacturing method comprising:
a forming process of forming the hat-shaped cross-section component by configuring
a metal sheet that is curved up-down by gripping a central portion of the metal sheet between
the punch and the pad, and gripping both side portions of the metal sheet between the die and
the holder, and moving the holder and die, and the punch and pad, up-down relative to each
other; and
a demolding process of demolding the hat-shaped cross-section component by
moving one or both of the die or the holder in a demolding direction, in a state in which the
pad and the pressure limiting section are in contact with each Other.