[Name of Document] DESCRIPTION
[Title of the Invention] PRESS-MOLDED PRODUCT, PRESS-MOLDED
PRODUCT PRODUCING METHOD, AND PRESS-MOLDED PRODUCT
PRODUCING APPARATUS
5 [Technical Field]
[000 I]
The present invention relates to a press-molded product having excellent
rigidity and strength and appropriately used as, for example, a vehicle body
reinforcing member and also relates to a press-molded product producing method
10 and a press-molded product producing apparatus used to produce the press-molded
product.
[Background Att]
[0002]
A vehicle body has a structure in which a plurality of molding panels is
15 bonded into a box shape by, for example, resistance spot-welding while edge
portions of the molding panels overlap one another. A reinforcing member or a
strengthening member (hereinafter, generally referred to as a "reinforcing member")
is bonded to the box-shaped structure by, for example, resistance spot-welding. As
such vehicle body reinforcing members, there are a bumper reinforcement, a locker
20 (side sill), a beltline, a cross member, and a side member.
[0003]
Each of these reinforcing members is formed as, for example, a
press-molded member that has a substantially hat-shaped or groove-shaped
cross-section and includes a ceiling plate, two ridge lines connected to the ceiling
25 plate, and two flanges connected to two ridge lines. An end portion opened in the
extension direction of the ridge line of such a reinforcing member is bent inward or
2
outward so as to form a flange in the end portion. When the flange overlaps the
other member and the flange and the other member are bonded to each other by, for
example, resistance spot-welding, a vehicle body reinforcing member is assembled.
Depending on the plate thickness of the material, arc-welding may be used instead of
5 spot-welding.
[0004]
Here, in the specification, an area in which an angle formed by two surfaces
respectively cmmected to both ends of the ridge line is smaller than 180° will be
referred to as an inner area, and a flange obtained by bending the end portion of the
10 reinforcing member toward the inner area will be referred to as an inward flange.
Further, an area in which an angle formed by two surfaces respectively cmmected to
both ends of the ridge line is larger than 180° will be referred to as an outer area, and
a flange obtained by bending the end portion of the reinforcing member toward the
outer area will be referred to as an outward flange.
15 [0005]
When the inward flange is formed in the end pmiion of the reinforcing
member, a ridge-portion flange located on the extension line of the ridge line is
molded as a flange by sluink:ing, and hence wrinkles are generated in the
ridge-portion flange. For that reason, when such an inward flange overlaps the
20 other member and the inward flange and the other member are bonded to each other
by spot-welding, a gap is generated between the inward flange and the other member
due to the wrinkles, and hence there is a concern that an assembling problem may
occur. Thus, when the reinforcing member having the inward flange formed at the
end portion is used, there is a need to weld the reinforcing member to the other
25 member by using the inward flange as a bonding edge while avoiding the generation
of wrinkles by, for example, forming a notch in the ridge-portion flange.
3
(0006)
However, when the notch is formed in the inward ridge-portion flange so
that the flange is not continuous, the performance of the vehicle body reinforcing
member involved with torsional rigidity or load transfer efficiency is essentially
5 degraded. Thus, in order to ensure the performance demanded for the reinforcing
member by bonding the reinforcing member to the other member through the inward
flange, there is a need to mold the shrinking flange while suppressing the generation
of wrinkles in the ridge-portion flange without any notch formed in the inward
flange.
10 (0007)
In addition, in the specification, the "notch formed in the flange" indicates a
state where the notch is formed in the entire flange in the width direction so that the
flange is not continuous. Further, the width of the flange is used as the meaning of
the height of the flange. Thus, when the width of the flange is partially decreased
15 so that a pmi of the flange is left, the notch is not formed in the flange.
(0008)
So far, a technique of suppressing the generation of wrinkles during the
shrinking flange molding process has been proposed. For example, Patent
Literature I discloses a technique of forming an unevenness shape, absorbing a
20 difference in length between a front end portion and a base portion in a sluinking
flange portion, in a roof panel having a sunroof opening. Further, Patent Literature
2 discloses a technique of preventing the generation of wrinkles by providing a
specific drawing bead in a shrinking flange pmiion during a rectangular tube drawing
process. Furthermore, Patent Literature 3 discloses a technique of suppressing the
25 generation of wrinkles by performing a molding process while applying a pressure to
a sln·inking flange portion using a cam structure.
4
[0009]
Further, Patent Literature 4 discloses a plate member molding method in
which a flange corresponding portion extending in a direction interesting a bending
load direction is formed in a portion to be used as a bent pmtion and the flange
5 corresponding pmtion is stretched into a flange so as to have a desired shape. Such
a plate member molding method is used to suppress tearing caused by the wrinkles in
the flange.
[0010]
Patent Literature 5 discloses a method in which a plane metal member is
10 bent, upright pmtions of both side pmtions are bent outward, and both inclined side
portions are strongly pressed by a processing roller of a pressing surface of a side
surface of a receiving die so as to be sequentially raised. Such a processing method
is used to reduce . .the .distortion or the wrinkles of the upright portion.
[Prior Att Literature( s)]
15 [Patent Literature(s)]
[00 II]
[Patent Literature 1] JP 2554768B
[Patent Literature 2] JP 2560416B
[Patent Literature 3] JP I-I4-118118A
20 [Patent Literature 4] JP S59-144530A
[Patent Literature 5] JP HI-I 04420A
[Sunm1ary of the Invention]
25
[Problem( s) to Be Solved by the Invention]
[0012]
The techniques disclosed in Patent Literatures 1 and 2 are used to absorb the
extra line length causing the generation of wrinkles and excessive padding by an
5
excessive portion formed in advance. Thus, the spot-welding is not easily
performed on the excessive portion and the excessive portion disturbs the
spot-welding of the other portion. In such a case, it is difficult to perform the
techniques disclosed in Patent Literatures 1 and 2.
5 [0013]
Fmiher, the technique disclosed in Patent Literature 3 can suppress the
generation of wrinkles of the flange portion of the large-curvature-radius portion
having, for example, a curvature radius of 2100 mm and having a feature that the
shrinkage rate of the flange portion and the reaction force for the cam structure are
10 small. However, it is difficult to suppress the generation of wrinkles of the flange
p01iion of the small-curvature-radius portion having, for example, a curvature radius
of 5 mm and having a feature that the shrinkage rate of the flange portion and the
reaction force.for.the .cam structure are large. Pmiicularly, when a high-tensile steel
plate having a large tensile strength is used, excessive wrinkles are generated, and
15 hence the reaction force from the flange portion increases. For that reason, the cam
stmcture disclosed in Patent Literature 3 cannot suppress the generation of wrinkles.
[0014]
Fmiher, the technique disclosed in Patent Literature 4 is used to suppress the
generation of wrinkles by the stretching process. Thus, the plate thickness of the
20 obtained flange is decreased. As a result, there is a concern that the rigidity of the
reinforcing member or the strength of the flange p01iion may be degraded.
[0015]
Further, the technique disclosed in Patent Literature 5 is used to form the
upright portion by sequentially strongly pressing a plurality of processing rollers.
25 Here, a product in which the curvature radius of the bent portion of the plane metal
member is comparatively large is considered as a target. Thus, it is difficult to
6
suppress the generation of wrinkles of, for example, the flange portion of the
small-curvature-radius pmtion having a curvature radius of 5 mm.
[0016]
In this way, in the member having a substantially hat -shaped or
5 groove-shaped cross-section, it is difficult to form the inward flange without forming
the notch in the end portion opened in the extension direction of the ridge portion
from the viewpoint of press-moldability. Particularly, Patent Literatures 1 to 5
above are not contrived in consideration of the formation of the flange in the
high-tensile steel plate having a tensile strength of 340 MPa or more. For that
10 reason, there is no example in which a press-molded product formed by a
high-tensile steel plate and including a continuous, inward flange without a notch in
a ridge-pmtion flange is used as the vehicle body reinforcing member so far.
[0017]
In a press-molded product having an outward flange, a hat-shaped or
15 groove-shaped cross-section cannot be enlarged to the fullest extent of the design
cross-section by the area of the outward flange. In other words, when the
press-molded product can be bonded to the other member through the inward flange
instead of the outward flange, the cross-section of the press-molded product can be
enlarged to the fullest extent of the design cross-section by the area in which the
20 outward flange · is not provided. For that reason, it is possible to improve the
bonding strength between the vehicle body reinforcing member and the other
member or the bending rigidity or the torsional rigidity of the vehicle body. Thus,
there is a desire to realize a press-molded product formed by a high-tensile steel plate
and including an inward continuous flange.
25 [0018]
An object of the invention is to provide a press-molded product including an
7
inward continuous flange without a notch and capable of improving performance
involved with the bonding strength between a reinforcing member and the other
member or the rigidity of a vehicle body without forming a notch in a ridge-pmiion
flange so as to prevent a defect generated during a press-molding process. Fmiher,
5 another object of the invention is to provide a press-molded product producing
method and a press-molded product producing apparatus.
[Means for Solving the Problem(s)]
[0019]
In order to solve the above problems, according to an aspect of the present
10 invention, there is provided a press-molded product of a metal plate which is formed
by a steel plate having a tensile strength of 340 MPa or more and includes a ridge
portion extending in a predetermined direction and first and second surface pmiions
respectively extending from both ends of a ridge line formed by the ridge portion, the
press-molded product including: an inward continuous flange in at least one end
15 pmiion in the predetermined direction. The inward continuous flange is obtained by
continuously forming a ridge-pmiion flange formed inward in an end pmiion of the
ridge portion, a first flange formed inward in at least a pati of an area of an end
portion of the first surface pmiion, and a second flange formed inward in at least a
pmi of an area of an end pmiion of the second surface portion. Regarding a plate
20 thickness of an edge portion of the ridge-portion flange, the ridge-potiion flange has
a plate thickness distribution in which a plate thickness of a portion of each of areas
on both sides of a circumferential center area is equal to or larger than a plate
thickness of the center area.
25
[0020]
The ridge-portion flange may have a maximal plate thickness at three
positions of the center area and the areas on the both sides, and the plate thickness of
5
8
the positions of the areas on the both sides having a maximal plate thickness may be
larger than the plate thickness of the position of the center area having a maximal
plate thickness.
[0021]
A flange width of at least a part of the ridge-portion flange may be smaller
than a flange width of each of the first flange and the second flange.
[0022]
A flange width (Lf) of the ridge-pottion flange and a curvature radius (rf) of
the ridge portion may satisfy Equation ( 1) below:
10 0.2 x rf :<; Lf :<; rf... (1 ).
[0023]
A cross-section of the press-molded product when viewed in the
predetermined direction may be a substantially hat -shaped or groove-shaped opened
cross-section or a closed cross-section.
15 [0024]
The press-molded product may be a vehicle body reinforcing member.
[0025]
In order to solve the above problems, according to another aspect of the
present invention, there is provided a press-molded product producing method for a
20 work which is formed by a steel plate having a tensile strength of 340 MPa or more
and includes a ridge pottion extending in a predetermined direction and first and
second surface portions respectively extending from both ends of a ridge line formed
by the ridge portion, a flange being formed in at least one end portion of the work in
the predetermined direction, the press-molded product producing method including:
25 an installation step of suppmting an area excluding the end portion of the work from
an inner area of the work; and a bending step of, using a bending tool having a
9
protrusion portion, bringing the protrusion portion into contact with a predetermined
position of the ridge portion in the end portion of the work from an outer area of the
work and then relatively moving the bending tool in a plate thickness direction of the
predetermined position in a direction toward the im1er area so as to form the flange.
5 [0026]
In the bending step, the flange may be formed in a mam1er that the
protrusion portion of the bending tool presses the predetermined position of the ridge
portion in the end portion in accordance with the movement of the bending tool so as
to bend the predetermined position in a plate thickness direction and then a pmiion
10 other than the protrusion pmiion of the bending tool sequentially presses an other
portion excluding the predetermined position in the end portion so as to bend the
other portion in a plate thickness direction.
[0027]
The predetermined position may be an area substantially having a width of a
15 plate thickness and including a circumferential center portion and both sides of the
circumferential center portion of the ridge portion. The protrusion pmiion may
press the predetermined position in a plate thickness direction of the center pmiion.
[0028]
In order to solve the above problems, according to still another aspect of the
20 present invention, ·there is provided a press-molded product producing apparatus
including: a work supporting tool which suppmis a work including a ridge po1iion
extending in a predetermined direction and first and second surface portions
respectively extending from both ends of a ridge line formed by the ridge portion
from an i1mer area of the work; and a bending tool which relatively moves in a
25 direction toward the im1er area of the work while contacting an end pmiion of the
work in the predetermined direction so as to bend the end portion in a direction
10
toward the i1mer area. The bending tool includes a protrusion portion which
contacts a predetermined position in the end portion of the ridge portion and presses
the predetermined position in a plate thickness direction of the predetermined
position in accordance with the movement.
5 [0029]
10
When the bending tool is viewed in the predetermined direction, a width of
the protrusion portion may decrease in a direction toward a front end portion and the
front end portion may form a curve.
[0030]
A height (h) of the protrusion p01tion and a curvature radius (rf) of the ridge
p01tion may satisfy Equation (2) below:
0.5 x rfs h s 3.0 x rf... (2).
[Effect(s) of the Invention]
15 [0031]
According to the invention, it is possible to suppress the generation of
wrinkles in an inward continuous flange without forming a notch in a ridge-portion
flange in order to prevent a defect generated during a press-molding process in a
press-molded product formed by a high-tensile steel plate. Thus, when the
20 press-molded product·is used as a vehicle body reinforcing member, it is possible to
improve performance involved with the bonding strength between the reinforcing
member and the other member or the rigidity of a vehicle body.
25
[Brief Description of the Drawing(s)]
[0032]
[FfG. I] FIG. I is a perspective v1ew schematically illustrating a
press-molded product having a hat-shaped cross-section according to a first
II
embodiment of the invention.
[FIG. 2] FIG. 2(a) is an explanatory diagram schematically illustrating a
shape of an inward continuous flange and FIG. 2(b) is an explanatory diagram
illustrating a ridge-portion flange when viewed from the front side.
5 [FIG. 3) FIG. 3 is an explanatory diagram illustrating examples of
cross-section shapes of press-molded products according to the same embodiment.
[FIG. 4] FIG. 4 is a graph illustrating an example of a plate thickness
distribution of a ridge-portion flange.
[FIG. 5) FIG. 5 is a schematic diagram schematically illustrating an entire
10 configuration example of a press-molded product producing apparatus for a bending
process.
[FIG. 6) FIG. 6 is an explanatory diagram schematically illustrating an
example of a drawing device.
[FIG. 7] FIG. 7 is an explanat01y diagram schematically illustrating an
15 example of a bending device.
[FIG. 8) FIG. 8(a) is a diagram illustrating a state where a work is attached
to a work supp01iing tool, FIG. 8(b) is a diagram illustrating a state where a bending
process statis, FIG. 8( c) illustrates a state where the bending process is being
performed, and FIG. 8( d) is a diagram illustrating a state where the bending process
20 ends.
[FIG. 9) FIG. 9 is an explanatory diagram illustrating a state where a
protrusion portion provided in a surface of a bending tool contacts an end portion of
a ridge p01iion.
[FIG. 10] FIG. lO(a) is a perspective view illustrating an end portion of a
25 work to be bent, FIG. 9(b) is a perspective view illustrating the end p01iion of the
work of which a ridge portion is being bent, and FIG. I 0( c) is a perspective view
12
illustrating the end portion of the work when the bending process ends.
[FIG. II] FIG. II (a) is a diagram schematically illustrating a shape of a
bending tool with a protrusion portion and FIG. II (b) is an explanatory diagram
illustrating a flange deformation state in the vicinity of a ridge-portion flange .
. 5 [FIG. 12] FIG. 12 is a diagram schematically illustrating a shape of a straight
10
bending tool without a protrusion portion and FIG. 12(b) is an explanatmy diagram
illustrating a flange deformation state in the vicinity of a ridge-portion flange.
[FIG. 13] FIG. 13 is a graph illustrating a plate thickness increase rate of a
ridge-portion flange in accordance with a bending process.
[FIG. 14] FIGS. 14(a) and 14(b) are external views illustrating a shape of a
press-molded product having an inward continuous flange.
[FIG. 15] FIG. 15 is a graph illustrating a plate thickness distribution of a
ridge-portion flange.
[Mode(s) for Carrying out the Invention]
15 [0033]
Hereinafter, referring to the appended drawings, preferred embodiments of
the present invention will be described in detail. It should be noted that, in this
specification and the appended drawings, structural elements that have substantially
the same function and structure are denoted with the same reference numerals, and
20 repeated explanation thereof is omitted.
[0034]
<1. First Embodiment>
First, a press-molded product according to a first embodiment of the
invention will be described.
25 [0035]
(1-1. Entire Configuration)
13
FIG. I is a perspective vtew schematically illustrating a press-molded
product I 00 according to the embodiment. FIG. 2(a) is an explanatory diagram
schematically illustrating a shape of an inward continuous flange I I 8 of the
press-molded product 100. FIG. 2(b) is a view (a front view of a ridge-portion
5 flange liSa) when viewed from A in FIG. I and is an enlarged view of an area
surrounded by the dashed line in FIG. 2(a).
[0036]
The press-molded product 100 according to the embodiment is a
press-molded product of a metal plate which is formed by a high-tensile steel plate
10 having a tensile strength of 340 MPa or more and includes ridge potiions 112a and
ll2b which extend in a predetermined direction and first surface pmiions I I 3a and
ll3b and a second surface portion 114 which respectively extend from both ends of
the ridge lines formed by the ridge portions ll2a and ll2b.
15
[0037]
Such a press-molded product I 00 includes, in at least one end portion in a
predetermined direction, the inward continuous flange I I 8 obtained by continuously
forming ridge-portion flanges liSa and l!Sb which are formed in the end pmiions of
the ridge pmiions ll2a and ll2b so as to be directed inward, first flanges 116a and
116b which are formed in at least a part of the area of the end portions of the first
20 surface portions I 13a and ll3b so as to be directed inward, and a second flange ll7
which is formed in at least a part of the area of the end portion of the second surface
portion 114 so as to be directed inward.
[0038]
Regarding the plate thickness of the edge portions of the ridge-pmiion
25 flanges liSa and liSb of the press-molded product I 00, the ridge-pmiion flanges
liSa and I ISb have a plate thickness distribution in which portions of areas on both
14
sides of the center area in the circumferential direction have plate thicknesses equal
to or larger than the plate thickness of the center area. For example, as illustrated in
FIG. 2(b), the center area of the edge portion of the ridge-pmtion flange liSa in the
circumferential direction is defined as an area X including a center pmtion Rc as the
5 intermediate point of positions RI and R2 in which the plate thickness starts to
increase from both ends of the edge portion of the ridge-portion flange llSa in the
circumferential direction. Such a center area X can be set as a center area X when
the area from the position Rl to the position R2 in the edge portion of the
ridge-portion flange liSa is divided into three pat1s in the circumferential direction.
10 [0039]
The press-molded product according to the embodiment is a molded product
obtained by press-molding a steel plate. Such a press-molded product is suitable for,
for example, .a. vehicle body reinforcing member such as a bumper reinforcement, a
locker (side sill), a beltline, and a cross member. The press-molded product used
15 for such an application may be obtained by press-molding a high-tensile steel plate
having a tensile strength of 340 MPa or more and desirably S90 MPa or more. The
tensile strength is a value measured by the tensile test based on JIS Z 2241. Further,
the plate thickness of the blank formed by the steel plate may be, for example, in the
range of0.8 to 2.0 mm.
20 [0040]
In the embodiment, the longitudinal direction of the press-molded product
l 00 or the blank corresponds to the extension direction of the ridge portions 112a and
ll2b of the press-molded product 100, but the extension direction of the ridge
portions 112a and 112b is not limited to the longitudinal direction of the
25 press-molded product 100. Further, in the embodiment, a predetermined direction
in which the ridge pmtions ll2a and I l2b extend is not limited to a direction which
15
is recognized as a straight line. A direction which is recognized as a curved shape
(curve) other than the straight line found in many vehicle body reinforcing members
is also included in the predetermined direction. When the predetermined direction
is recognized as a curve, the predetermined direction includes, for example, a
5 direction which is curved in the left and right direction or the up and down direction
of the reinforcing member or a direction obtained by the combination of these
directions. Further, the entire length in the predetermined direction includes, for
example, all kinds of length from the length of about 1000 mm of a bumper or a side
member to the length of about 100 mm of a cubic bulkhead.
10 [0041]
FIG. 3 is an explanatory diagram illustrating an example of a cross-section
shape of the press-molded product 100 in a cross-section orthogonal to the
longitudinal directinn,of the press-molded product 100. The cross-section shape of
the press-molded product 100 according to the embodiment can be set to a
15 hat-shaped cross-section illustrated in FIG. 3(A) or a groove-shaped cross-section
illustrated in FIG. 3(B), but the invention is not limited thereto. As illustrated in
FIG. 3(C) or 3(D), the cross-section shape of the press-molded product 100 includes
a cross-section shape in which a convex shape 1 OOb or a concave shape (not
illustrated) is provided in a wall surface 1 OOa in a hat -shaped or groove-shaped
20 cross-section.
[0042]
Fmiher, the cross-section shape of the press-molded product 100 also
includes, for example, a substantially rectangle-shaped closed cross-section shape
other than the opened cross-section shapes illustrated in FIGS. 3(A) to 3(D). In
25 addition, the press-molded product I 00 is not limited to these cross-section shapes.
For example, a press-molded product having a cross-section shape including a ridge
16
portion and a first surface pmtion and a second surface portion respectively
extending from both ends of the ridge line formed by the ridge portion and called a
V-shaped cross-section may be used. The press-molded product I 00 illustrated in
FIG. I is the press-molded product I 00 having a hat-shaped cross-section.
5 Hereinafter, the press-molded product 100 having a hat-shaped cross-section will be
described as an example.
[0043]
As illustrated in FIG. 1, the press-molded product 100 includes the ridge
portions 112a and ll2b, the first surface portions 113a and ll3b, and the second
10 surface pmiion 114. Both ridge pmiions 112a and ll2b are formed so as to extend
in the longitudinal direction of the press-molded product 100. One first surface
portion ll3a is connected to the ridge portion ll2a and is formed so as to extend in
the first direction. intersecting the longitudinal direction of the press-molded product
100. The other first surface pmiion ll3b is connected to the ridge pmiion 112b and
15 is formed so as to extend in the first direction intersecting the longitudinal direction
of the press-molded product 100. The first direction as the extension direction of
one first surface portion 113a and the first direction as the extension direction of the
other first surface portion ll3b may be different from each other.
20
[0044]
The second surface portion 114 is connected to the ridge portions 112a and
112b and is formed so as to intersect the longitudinal direction of the press-molded
product 100 and to extend in a second direction different from the first direction.
The second surface pmiion 114 is formed between the ridge portions 112a and 112b.
In this way, the press-molded product I 00 has a substantially hat-shaped opened
25 cross-section including the ridge portions 112a and ll2b which extend in the
longitudinal direction of the press-molded product 100 and including the first surface
17
portions 113a and 113b and the second surface portion 114 which are continuous to
the ridge portions 112a and 112b.
[004S]
(1-2. Inward Continuous Flange)
5 The press-molded product 100 includes the ridge-portion flanges 11Sa and
llSb, the first flanges 116a and 116b, and the second flange 117 provided in at least
one outer end portion 1 OOA in the longitudinal direction. The ridge-pmiion flanges
liSa and llSb are formed at the outer end portion 1 OOA in the longitudinal direction
of the ridge portions 112a and 112b. The first flanges 116a and 116b are formed in
10 at least a pati of the area of the outer end pmiion 1 OOA in the longitudinal direction
of the first surface potiions 113a and 113b. Further, the second flange 117 is
formed in at least a part of the area of the outer end portion IOOAin the longitudinal
direction of the second surface portion 114. In the embodiment, the first flanges
116a and 116b and the second flange 117 are formed in the entire area of the outer
15 end pmiion 1 OOA of each of the first surface portions 113a and 113b and the second
surface portion 114.
[0046]
The ridge-portion flanges 11Sa and 11Sb, the first flanges 116a and 116b,
and the second flange 117 are all formed continuously as the inward flange. The
20 ridge-portion flanges liSa and llSb, the first flanges 116a and 116b, and the second
flange 117 constitute the inward continuous flange 118. Since the flange provided
in the end pmiion of the press-molded product 100 is formed as the inward
continuous flange 118, for example, the cross-section of the vehicle body reinforcing
member can be enlarged to the fullest extent of the design cross-section. Thus, it is
25 possible to further improve the bonding strength between the reinforcing member
and the other member or the rigidity of the vehicle body.
18
[0047]
The press-molded product I 00 according to the embodiment includes the
inward continuous flange 118 provided in the longitudinal outer end portion I OOA so
as to be continuous in the entire length of the first surface portions 113a and 113b,
5 the ridge portions 112a and 112b, and the second surface potiion 114. Here, the
first flanges 116a and 116b and the second flange 117 may be continuous to the
ridge-pmiion flanges liSa and 115b and the inward continuous flange 118 is not
necessarily continuous in the entire length. For example, the first flanges 116a and
116b or the second flange 117 may be formed in a part of the area of the outer end
10 portion 100A of the first surface portions 113a and 113b or the second surface
pmiion 114. When the second flange 117 is not formed in the entire area of the
second surface portion 114, two divided inward continuous flanges 118 are formed.
[0048]
When the press-molded product 100 is used as the vehicle body reinforcing
15 member, the press-molded product I 00 and the other member can overlap each other
with the inward continuous flange 118 interposed therebetween. Then, the
press-molded product 100 and the other member are bonded to each other by, for
example, spot-welding the inward continuous flange 118.
[0049]
20 In addition, when a spot-welding process is performed on the press-molded
product 100, for example, the welding process may be performed as below. First,
the press-molded product I 00 is made to abut on the side surface of the other
member and then the inward continuous flange 118 is welded by a C-type
spot-welding gun. Subsequently, a closing plate is welded while abutting on the
25 flanges provided in the end portions of the first surface pmiions 113a and 113b of the
press-molded product I 00 in a direction intersecting the extension direction of the
19
ridge pmiions 112a and 112b. Accordingly, the opening portion of the hat-shaped
press-molded product I 00 is closed and the press-molded product 100 is assembled.
The same applies to the welding of the closing plate in the other member. When the
press-molded product I 00 cannot be fixed by the spot-welding gun, the other
5 welding means such as one-way welding, TIG welding, laser welding, and adhering
maybe used.
[OOSO]
(1-3. Ridge-portion Flange)
In the press-molded product 100 according to the embodiment, it is
10 desirable that the width Lf and the curvature radius rf of each of the ridge-portion
flanges liSa and l!Sb satisfy Equation ( 1) as below.
0.2 x rf"' Lf"' rf... (1)
[OOSI]
When the width Lf of each of the ridge-portion flanges liSa and IISb is
15 equal to or smaller than the curvature radius rf, the moldability of the inward
continuous flange 118 becomes satisfactory while the generation of wrinkles is
suppressed. Further, when the width Lf of each of the ridge-pmiion flanges llSa
and llSb is equal to or larger than 0.2 times the curvature radius rf, it is possible to
ensure the rigidity of the ridge-portion flanges liSa and llSb and to ensure the
20 strength of the·press-molded product I 00 suitable for the vehicle body reinforcing
member.
[OOS2]
When the width Lf and the curvature radius rf of each of the ridge-portion
flanges liSa and llSb satisfy Equation (1) above, the flange width of each of the
25 ridge-pmiion flanges liSa and 115b may be set to be small so that the ridge-portion
flanges do not reach the inner surfaces of the ridge pmiions 112a and 112b. That is,
20
the width Lf of each of the ridge-portion flanges liSa and IISb may be smaller than
the widths Lfsl and Lfs2 of each of the first flanges 116a and 116b or the second
flange 117. Patiicularly, when a work formed by a high-tensile steel plate or a steel
plate having a large plate thickness is used, it is desirable to decrease the flange
5 width Lf of each of the ridge-pmiion flanges llSa and l!Sb.
[OOS3]
In the press-molded product 100 according to the embodiment, a concave
portion 119 is provided in each of the ridge-portion flanges llSa and l!Sb.
Accordingly, the width Lf of each of the ridge-portion flanges llSa and l!Sb is
10 smaller than the widths Lfs1 and Lfs2 of each of the first flanges 116a and 116b and
the second flange 117 in an area corresponding to the vertex of each of the ridge lines
formed by the ridge portions 112a and 112b. Further, the width of the flange
indicates a flat .pmtion.,except for a curved portion formed in the base pmiion in
which the flange is uprightly formed from the ridge pmiion, the first surface portion,
15 or the second surface portion.
[OOS4]
For example, in the ridge-portion flange llSa, as illustrated in FIG. 2(b), the
width Lf of the ridge-portion flange llSa indicates the width Lf of a flat portion
llSaa except for a curved pmiion l!Sab formed so as to be continuous to the ridge
20 pmiion 112a inihe longitudinal outer end pmiion 1 OOA. Since the width Lf of each
of the ridge-pmiion flanges liSa and l!Sb is smaller than the widths of the first
flanges 116a and 116b and the second flange 117, the extra extension amount of the
front end of the flange of each of the ridge-pmiion flanges liSa and I!Sb is small,
and hence the generation of wrinkles is reduced.
25 [OOSS]
(1-4. Plate Thickness Distribution)
21
Here, the plate thickness distribution of the ridge-portion flanges liSa and
IISb of the press-molded product I 00 according to the embodiment will be described.
FIG. 4 is a graph illustrating an example of the plate thickness distribution for the end
portion of the ridge-portion flange liSa in the width direction. The vertical axis
5 indicates a plate thickness increase rate (%). The plate thickness increase rate
indicates the plate thickness increase rate of the end portion of the flange in the width
direction based on the plate thickness of the blank to be press-molded.
[OOS6]
Further, the horizontal axis indicates the distance (mm) of the edge pmiion
10 of the ridge-portion flange liSa. The "distance of the edge portion of the flange"
indicates a position in the circumferential direction from a position in which the plate
thickness of the edge portion of the ridge-pmiion flange liSa stmis to increase along
the ridge line, .serving as the stmiing point 0, to a position in which the plate
thickness stops to increase. Specifically, as illustrated in FIG. 2(b ), the distance
15 indicates a position in the circumferential direction from a plate thickness increase
stmi position Rl to a plate thickness increase end position R2 in the end pmiion of
the ridge-portion flange liSa in the width direction. In the example of FIG. 2(b ),
the plate thickness increase stmi position Rl is located near the first surface portion
113a, and the plate thickness increase end position R2 is located near the second
20 surface pmiion H 4. However, the plate thickness increase stmi position Rl and the
plate thickness increase end position R2 may be located at the reverse positions.
The intermediate.point between the plate thickness increase start position Rl and the
plate thickness increase end position R2 indicates a circumferential center portion Rc
of the edge portion of the ridge-pmiion flange liSa in the width direction.
25 [OOS7]
As illustrated in FIG. 4, the ridge-portion flange liSa of the press-molded
22
product 100 according to the embodiment includes positions C I and C2 which are
provided at both sides of the center area including the circumferential center portion
Rc, the plate thickness of the edge pmiion of the positions C I and C2 being larger
than the plate thickness of the edge pmiion of the center portion Rc. Specifically,
5 the plate thickness distribution illustrated in FIG. 4 includes a position A which is
located at the circumferential center portion Rc so that the plate thickness is maximal,
positions B 1 and B2 which are located at both sides of the position A so that the plate
thickness is minimal, and positions Cl and C2 which are located outside the
positions B I and B2 so that the plate thickness is maximal. That is, the plate
10 thickness is maximal at three positions of the ridge-portion flange 115a in the
circumferential direction. The plate thickness of each of positions C I and C2 on
both sides between which the center area is interposed is larger than the plate
thickness of the cir.cwnferential center portion Rc (A).
15
[0058]
Since the ridge-portion flanges 115a and 115b have such a plate thickness
distribution, wrinkles generated by the ridge-pmiion flanges 115a and 115b are
distributed. Accordingly, it is possible to suppress a problem in which buckling
wrinkles are intensively generated in the circumferential center area of each of the
ridge-pmiion flanges 115a and 115b. Thus, when the press-molded product 100
20 and the other member arc bonded to each other by spot-welding through the inward
25
continuous flange 118, a gap is not easily formed between each of the ridge-portion
flanges 115a and l!Sb and the other member. As a result, the bonding strength can
be improved.
[0059]
Further, it is desirable that a ratio between the maxnnum value of the
position A having a maximal plate thickness in the circumferential center area and
23
the maximum value of each of the positions Cl and C2 provided at both sides ofthc
center area so as to have a maximal plate thickness be substantially in the range of
1.0 to 1.5. Such a ratio can be changed by the curvature radius rf of each of the
ridge portions 112a and 112b or the strength and the work-hardening coefficient of
5 the metal plate (for example, the high-tensile steel plate having a tensile strength of
340 MPa or more) as the blank material of the press-molded product I 00.
[0060]
Since the above-described ratio is in the range of 1.0 to 1.5, the degree of
wrinkles generated in the ridge-p01iion flanges 115a and 115b decreases. Thus, a
10 gap is not easily formed when the press-molded product I 00 is bonded to the other
member by spot-welding through the ridge-portion flanges liSa and IJSb, and hence
degradation in bonding strength can be suppressed.
[0061]
As described above, the press-molded product I 00 according to the
15 embodiment can be bonded to the other member through the inward continuous
flange 118 instead of the outward flange. Thus, the hat-shaped cross-section or the
groove-shaped cross-section can be enlarged to the fullest extent of the design
cross-section by the area in which the outward flange is not provided. Further, in
the press-molded product 100 according to the embodiment, the generation of
20 wrinkles in the inward continuous flange 118 is suppressed without any notch formed
in the ridge-portion flanges 115a and l!Sb. Thus, when the press-molded product
I 00 is used as, for example the vehicle body reinforcing member, it is possible to
improve the bonding strength between the press-molded product 1 00 and the other
member and to improve the performance involved with the rigidity or the load
25 transfer efficiency of the reinforcing member.
[0062]
24
<2. Second Embodiment>
Next, an example of a method of producing the press-molded product I 00
according to a second embodiment of the invention will be described along with a
configuration example of an apparatus of producing the press-molded product I 00.
5 A method and an apparatus of producing the press-molded product 100 according to
the embodiment are used to produce, for example, the press-molded product 100
according to the first embodiment. Hereinafter, an apparatus (hereinafter, also
referred to as the "press-molding apparatus") of producing the press-molded product
100 according to the embodiment will be described and then a method of producing
10 the press-molded product 100 using the press-molding apparatus will be described.
[0063]
(2-1. Press-molding Apparatus)
FIG. 5 is a schematic diagram schematically illustrating an entire
configuration example of a press-molding apparatus 20 according to the embodiment.
15 As illustrated in FIG. 5, the press-molding apparatus 20 includes a work suppmiing
tool24 and first to third bending tools 21a, 21b, and 22. The work suppotiing tool
24 is used to fix and support a work 140 having a U-shaped cross-section. The
outer surface of the work supporting tool 24 has a shape corresponding to the shape
of the inner surface of the work 140 to be suppmied. The work supporting tool 24
20 supports the work 140 from the inner area while the end portion forming the flange
of the work 140 protmdes outward.
[0064]
In order to form the inward flange in the end pmiion of the work 140, the
first to third bending tools 21 a, 21 b, and 22 are used to press-insert the end portion
25 from the outer area to the inner area of the work 140 so that the work is bent inward.
Each of the first to third bending tools 21a, 21b, and 22 is formed by, for example, a
bending blade.
[0065]
25
The first to third bending tools 21 a, 21 b, and 22 move forward and
backward with respect to the work suppmiing tool 24 so as not to contact the work
5 supporting tool 24. Such a forward and backward movement is realized by, for
example, a cam structure (not illustrated). When the first to third bending tools 2la,
2lb, and 22 move forward relatively, at least a pati of the bending tools face a side
surface 24b in a pmiion causing the end pmiion of the work 140 to protrude outward
in the side surface of the work supp01iing tool 24. In accordance with such a
10 forward movement, the first to third bending tools 2la, 21 b, and 22 bend the end
portion of the work 140 inward.
[0066]
Fmiher, when the first to third bending tools 2la, 21b, and 22 move
backward relatively, the bending tools move backward to a position not facing the
15 side surface 24b. At such a backward movement position, the first to third bending
tools 21a, 2lb, and 22 are disposed so as not to be located on the extension line in the
longitudinal direction of the work 140. In the press-molding apparatus 20
according to the embodiment, the side surface 24b of the work suppmiing tool is
formed on one flat surface, and the first to third bending tools 21 a, 21 b, and 22 are
20 provided so as to be movable relatively within a plane parallel to the side surface
24b.
[0067]
The first and second bending tools 21 a and 21 b are provided so as to
correspond to shoulder pmiions 25a and 25b supporting ridge portions 142a and
25 142b of the work 140 in the work supporting tool24. The first and second bending
tools 2la and 2lb move forward and backward in a direction in which the shoulder
5
26
portions 25a and 25b are divided into two parts in the circumferential direction, that
is, a direction in which the ridge lines formed by the ridge portions 142a and 142b of
the work 140 are divided into two patis.
[0068]
Fmiher, the third bending tool 22 is provided at the substantial center
between the first bending tool 2la and the second bending tool 2lb. Such a third
bending tool 22 moves forward and backward in a direction mihogonal to a support
surface 24a of the work supporting tool 24 supporting a second surface portion 144
of the work 140. As described above, the first to third bending tools 21a, 21b, and
10 22 are used to press the end portion of the work 140 protruding from the work
suppmiing tool 24 and do not contact the work supporting tool24.
[0069]
In a state .. where the first to third bending tools 21 a, 21 b, and 22 move
fmward relatively so as to face the side surface 24b of the work supporting tool 24, it
15 is desirable that the distance x of the gap between each of the first to third bending
tools 2la, 2lb, and 22 and the work supporting tool24 satisfy Equation (3) as below.
1.00 X t ~X~ 1.40 X t ... (3)
20 [0070]
t: plate thickness (mm) of blank
w: distance (mm) of gap
Since the distance x of the gap satisfies Equation (3) above, it is possible to
suppress the plate thickness of the inward continuous flange 118 from being smaller
than the plate thickness before the press-molding process. Further, since the
distance x of the gap satisfies Equation (3) above, it is possible to suppress an
25 increase in plate thickness causing the generation of wrinkles in the ridgc-p01iion
flanges liSa and 115b.
27
[0071]
Here, the first and second bending tools 2la and 2lb include protrusion
portions 23a and 23b provided at the surfaces in the forward movement direction.
Such protrusion portions 23a and 23b press the end portions of the ridge pmiions
5 142a and 142b in the end pmiion of the work 140 protruding from the work
suppmiing tool 24 in the plate thickness direction. The end portion of the work 140
protruding from the work supporting tool 24 is a portion bent in the inward
continuous flange 118. Further, the end portions of the protmding ridge pmiions
142a and 142b are portions formed in the ridge-portion flanges liSa and llSb.
10 [0072]
The first and second bending tools 21 a and 21 b are disposed so that the
protmsion portions 23a and 23b contact a part of the end pmiions of the ridge
portions 142a .and .142b from the outer area when the bending process stmis.
Subsequently, the first and second bending tools 21 a and 21 b move forward
15 relatively toward the inner area in the plate thickness direction of the portions
contacting the protmsion portions 23a and 23b. In the end portions of the ridge
portions 142a and 142b, the portions contacting the protmsion pmiions 23a and 23b
are pressed in the plate thickness direction of the contact potiions. Meanwhile, the
other parts of the end portions of the ridge portions 142a and 142b are pressed in a
20 direction intersecting the plate thickness directions of the respective portions.
[0073]
In this way, when the end potiions of the ridge portions 142a and 142b are
pressed by the first and second bending tools 21 a and 21 b with the protmsion
portions 23a and 23b, a difference in deformation speed is generated between a
25 portion pressed by the protmsion pmiions 23a and 23b and the other portion. Thus,
a deformation field obtained when the ridge-portion flanges liSa and l!Sb are
28
formed in the end portions of the ridge portions 142a and 142b is changed from a
shrinking deformation field to a shearing deformation field. That is, it is supposed
that the deformation state of the ridge-portion flanges 115a and 115b is changed from
the shrinking deformation field (strain ratio~ (E2/d) <-I: increased plate thickness)
5 to the shearing defonnation field (strain ratio ~ (s2/sl)"' -I: uniform plate thickness).
Thus, it is possible to suppress an increase in plate thickness causing the generation
of wrinkles in the end portions of the ridge portions 142a and 142b.
[0074]
At this time, when the height h of each of the protrusion pmiions 23a and
10 23 b is too small, the shearing deformation field formed in the end portions of the
ridge portions 142a and 142b protmding from the work supporting tool 24 during the
bending process performed by the first and second bending tools 2la and 2lb is not
sufficient. As a result, there is a case in which an effect of suppressing an increase
in plate thickness decreases. Meanwhile, when the height h of each of the
15 protrusion portions 23a and 23b is too large, there is a concern that the protmsion
portions 23a and 23b may be damaged. Thus, it is desirable that the height h of
each of the protrusion pmiions 23a and 23b satisfy Equation (2) as below. Further,
the sign rf in Equation (2) below indicates the curvature radius of each of the ridge
portions 112a and 112b.
20 0.5 X Tf ~ h ~ 3.0 X rf ... (2)
[0075]
In the embodiment, in the shearing deformation field formed during the
bending process performed by the first and second bending tools 2la and 2lb, the
strain ratio ~ (s2/d) of the maximal strain pmiions of the ridge-portion flanges liSa
25 and 115b satisfies the incquation of -1.5 < (s2/d) < 0.9. In other words, the
protrusion portions 23a and 23b can give a shearing deformation field in which the
29
strain ratio p (s2/s I) of the maximal strain portions of the ridgc-pmtion flanges liSa
and 115b satisfies the inequation of -1.5 < (s2/El) < 0.9.
[0076]
In addition, the press-molding apparatus 20 may be provided as, for
5 example, a drawing device which draws a blank so as to form the work 140 including
the ridge pmtions 142a and 142b and the first surface portions 143a and 143b and the
second surface portion 144 being continuous to the ridge pmtions 142a and 142b.
For example, the press-molding apparatus 20 according to the embodiment may be
provided as an existing drawing device 50 including a die 51, a punch 53, and a
10 blank holder 55 illustrated in the example of FIG 6. Alternatively, the
press-molding apparatus 20 according to the embodiment may be provided as an
existing bending device 60 including a die 61 and a punch 63 illustrated in the
example of FIG 7.
15
[0077]
In this case, the press-molding apparatus 20 is provided in a manner that the
first to third bending tools 21 a, 21 b, and 22 are disposed ncar the side surface of the
die 51 or 61 and the bending tools 21a, 21b, and 22 are set to be movable relative to
the punch 53 or 63. According to such a press-molding apparatus 20, since the
punch serves as the work supporting tool 24, there is no need to use the dedicated
20 work supporting tool 24. Thus, it is possible to reduce the producing cost and the
number of the production steps of the press-molded product 100 compared with the
case where the dedicated work supporting tool 24 is used.
[0078]
Further, the press-molding apparatus 20 according to the embodiment is
25 provided as a bending device for bending the work 140 with two ridge portions 142a
and 142b. Such a press-molding apparatus 20 includes the first and second bending
30
tools 2la and 2lb which bend the end portions of the ridge portions 142a and 142b
and the third bending tool 22 which bends the end portion of the second surface
portion 144 of the work 140. Here, the press-molding apparatus 20 is not limited to
such an example.
5 [0079]
For example, the third bending tool 22 which bends the end portion of the
second surface portion 144 may be omitted when the width of the second surface
portion 144 is small. Further, for example, when a work having a V-shaped
cross-section with one ridge portion is bent, the press-molding apparatus may not
10 include the third bending tool 22. In this case, in order to press the end portion of
the ridge portion so that the end pmiion is bent inward, the press-molding apparatus
may include only the first bending tool2la with the protrusion portion 23a.
15
[0080]
(2-2. Press-molded Product Producing Method)
Next, a method of producing the press-molded product I 00 by bending the
end pmiion of the work 140 having a U-shaped cross-section using the
press-molding apparatus 20 according to the embodiment will be described.
[0081]
FIG. 8 is an explanatory diagram schematically illustrating a state where the
20 press-molded product I 00 is produced from the work 140 by the method of
producing the press-molded product I 00 according to the embodiment. FIG. 8(a)
illustrates a state where the work 140 is attached to the work supporting tool 24 and
FIG. 8(b) illustrates a state where the bending process for the work 140 starts.
Further, FIG. 8(c) illustrates a state where the work 140 is bent and FIG. S(d)
25 illustrates a state where the bending process for the work 140 ends.
[0082]
31
Further, FIG. 9 is an explanatory diagram illustrating a state where the
protrusion portions 23a and 23b provided in the surfaces of the first and second
bending tools 21 a and 21 b contact the work 140 and the protrusion portions 23a and
23 b press the contact portion of the work 140 in the plate thickness direction. In
5 addition, FIG. 10 is a perspective view illustrating a state where the end portion of
the work 140 is deformed by the method of producing the press-molded product 100
according to the embodiment. FIG. 10(a) illustrates the end portion of the work 140
to be bent, FIG. 1 O(b) illustrates the end portion of the work 140 of which the ridge
portion is being bent, and FIG. 1 0( c) illustrates the end portion of the work 140 when
10 the bending process ends.
[0083]
As illustrated in FIG. 8(a), the work 140 has aU-shaped cross-section with
the ridge portions l42a and 142b extending in the longitudinal direction and the first
surface pmiions 143a and 143b and the second surface portion 144 being continuous
15 to both ends of the ridge lines formed by the ridge pmiions 142a and 142b. In a
state where the longitudinal end pmiion 140a of such a work 140 protrudes from the
work supporting tool 24, the work 140 is fixed and supported while being covered by
the work suppmiing tool 24. The protruding end portion 140a is a portion to be
bent in the inward continuous flange 118. As illustrated in FIG. IO(a), the end
20 portion of the work 140 is not bent at the step in which the bending process is not
started yet.
[0084]
At that time, as illustrated in FIGS. 8(a) and 9, the first and second bending
tools 21a and 21 bare disposed so that the front ends of the protrusion portions 23a
25 and 23b provided in the respective surfaces of the first and second bending tools 21a
and 21b contact the end portions of the ridge pmiions 142a and 142b of the work 140.
32
In the embodiment, the protrusion portions 23a and 23b contact the center portion
dividing the ridge line into two parts in the end portions of the ridge portions 142a
and 142b. Further, the third bending tool 22 is disposed so as to contact the
substantial center portion of the end portion of the second surface pmtion 144
5 interposed between two ridge portions 142a and 142b.
[0085]
Next, as illustrated in FIG. 8(b), the first and second bending tools 2la and
21 b are moved from the outer area toward the inner area of the work 140 in the
inclination direction inclined with respect to the vertical direction by, for example, a
10 cam mechanism (not illustrated). Accordingly, the front ends of the protrusion
pmtions 23a and 23b press the circumferential center portions of the end portions of
the ridge portions 142a and 142b in the plate thickness direction. That is, as
indicated by .the .white .. arrow of FIG. 8(b), the first and second bending tools 2la and
21 b move in the inclination direction substantially dividing the ridge lines of the end
15 pmtions of the ridge pmtions 142a and 142b into two pmts.
[0086]
Accordingly, the circumferential center areas of the end pmtions of the ridge
portions 142a and 142b start to be deformed earlier than the other areas. At the
same time, the third bending tool 22 is similarly moved in the vertical direction by a
20 cam mechanism ~not illustrated), and the fi"ont end of the third bending tool 22
contacts the center portion of the end portion of the second surface pmtion 144. At
this time, it is desirable that the protrusion portions 23a and 23b of the first and
second bending tools 21a and 2lb press a pmt or the entirety of an area substantially
having a width of the plate thickness and including the circumferential center portion
25 and both sides of the circumferential center portion of each of the end portions of the
ridge portions 142a and 142b in the plate thickness direction of the corresponding
33
portion.
[0087]
With such a bending process, positions having a maximal plate thickness
and formed in each of the edge portions of the ridge-portion flanges 115a and 115b in
5 the width direction can be easily distributed evenly in the circumferential direction of
the ridge-pmtion flanges !!Sa and 115b. Thus, the generation of wrinkles in the
ridge-portion flanges 115a and 115b is further suppressed. From such a viewpoint,
it is more desirable to press and bend the circumferential center portions of the ridge
pmtions 142a and 142b in the plate thickness direction by the protrusion portions 23a
10 and 23b.
[0088]
Next, as illustrated in FIGS. 8(c) and 8(d), the first to third bending tools
2la, 2lb, and.22 are moved in the directions indicated by the white arrows so as to
bend the end portions of the work 140. That is, when the third bending tool 22 is
15 moved, the end portion of the second surface pmtion 144 is bent inward in the plate
thickness direction. Further, when the first and second bending tools 21 a and 21 b
are moved, the circumferential center portions of the end pmtions of the ridge
pmtions 142a and 142b are bent in the plate thickness direction. Futther, in
accordance with the movement of the first and second bending tools 21 a and 21 b, the
20 other portion except for the circumferential center portions of the end portions of the
ridge portions 142a and 142b are sequentially pressed from the center portions at the
timing later than the timing of pressing the circumferential center portions.
Accordingly, the other portions except for the center pmtions of the ridge portions
142a and 142b are sequentially bent in a direction intersecting the plate thickness
25 direction of the corresponding portion.
[0089]
34
That is, in the method of producing the press-molded product 100 according
to the embodiment, as illustrated in FIG. 1 O(b ), the end portion of the ridge portion
142b among the end pmiions of the work 140 is bent first. Subsequently, as
illustrated in FIG. 10(c), the end pmiions of the first surface pmiion 143b and the
5 second surface portion 144 are sequentially bent so as to form the inward continuous
flange 118.
[0090]
In the method of producing the press-molded product 100 according to the
embodiment, the circumferential center areas of the end portions of the ridge portions
10 142a and 142b stmi to be deformed earlier than the other areas, so that the
deformation speed of the center area becomes different from the deformation speed
of the pmiion other than the center area. For that reason, the deformation field of
each of the ridgecpmiion flanges ll5a and ll5b is changed from the deformation
field as the shrinking flange deformation field having a large increase in plate
15 thickness to the pure shearing deformation field, and hence an increase in plate
thickness easily causing the generation of wrinkles is suppressed. In this way, it is
possible to obtain the press-molded product 100 with the inward continuous flange
118 in which each of the ridge-portion flanges liSa and 115b is not provided with
the notch and the generation of wrinkles is suppressed.
20 [0091]
In the description above, an example is described in which the protrusion
portions 23a and 23b press the circumferential center portions of the end pmiions of
the ridge portions 142a and 142b of the work 140 in the plate thickness direction, but
the embodiment is not essentially limited to such an example. As long as the
25 circumferential center areas of the end potiions of the ridge pmiions 142a and 142b
are guaranteed, the positions other than the center portions dividing the ridge lines
35
into two parts may be pressed in the plate thickness direction.
[0092]
According to the method and the apparatus of producing the press-molded
product 100 according to the embodiment, a shearing deformation field is formed in
5 each of the ridge-pmiion flanges liSa and ll5b formed in the end portions of the
ridge portions 142a and 142b of the work 140 during the bending process. Thus, it
is possible to effectively suppress an increase in plate thickness of the ridge-portion
flanges liSa and ll5b caused by the shrinking deformation in accordance with the
bending deformation.
10 [0093]
In addition, when the press-molding apparatus 20 is provided by using the
existing drawing device or the bending device illustrated in FIG. 6 or 7, it is possible
to mold the work 140 and the inward continuous flange 118 according to a series of
processes as below. For example, first, the work 140 is molded by drawing or
15 bending a blank. Next, in a state where the work 140 is not separated from the
press-molding apparatus 20, the longitudinal end pmiion of the work 140 is bent
inward by the first to third bending tools 21 a, 21 b, and 22 disposed near the side
surface of the die 51 or 61 by using the punch 53 or 63 as the work supporting tool
24.
20 [0094]
In this way, it is possible to obtain the press-molded product 100 with the
inward continuous flange 118 through a series of processes. In this way, since the
press-molded product 100 is produced by using the single press-molding apparatus
20, it is possible to produce the press-molded product 100 at low cost and a small
25 number of steps.
[0095]
36
Further, in order to process (hereinafter, "trim") each of the ridge-portion
flanges 115a and 115b into a predetermined shape when the concave portion 119 is
formed in each of the ridge-portion flanges 115a and 115b, for example, the
press-molded product 100 can be produced according to the following procedures.
5 [0096]
(!) The work 140 having a predetermined cross-section shape is molded, the
longitudinal end portions of the ridge portions 142a and 142b of the work 140 are
trimmed, and then the end pottions of the work 140 are bent inward.
(2) The work 140 is molded and trimmed fi·om the blank so as to mold the
10 work 140 of which the longitudinal end portions of the ridge portions 142a and 142b
are processed into a predetermined shape, and then the end portions of the work 140
are bent inward.
(3) A pottion molded into the ridge-pottion flange in the blank is trimmed so
as to process the blank into a predetermined shape, the work 140 is then molded fi·om
15 the blank, and the end portion of the work 140 is bent inward.
[Examples]
[0097]
Hereinafter, Examples of the invention will be described with reference to a
numerical analysis result based on the finite element method.
20 [0098]
(Examples 1 to 5 and Comparative Examples 1 to 5)
First, a work having a V-shaped cross-section and formed by a high-tensile
steel plate with a plate thickness of 1.6 mm and a tensile strength of 980 MPa was
used, and the end pottion of the work was bent according to the procedure illustrated
25 in FIGS. 5 to 9 so as to produce a press-molded product having an inward continuous
flange. The deformation behavior of each of a ridge-portion flange and adjacent
37
first and second flanges during the production of the press-molded product was
analyzed by a numerical analysis.
[0099]
FIG. I I is an explanatory diagram illustrating Example of the invention in
5 which a bending process is performed by the first bending tool 21a with the
protrusion pmiion 23a. FIG. I 1(a) is a diagram illustrating a shape of the first
bending tool 2la. In the first bending tool 21a, the height h of the protrusion
portion 23a is 7 mm, and the curvature radius of the front end of the protrusion
portion 23a is 6 mm. FIG. 11(b) is an explanatory diagram illustrating the
10 deformation state of the ridge-portion flange 115, the first flange 116, and the second
flange 117 of the press-molded product in Examples 1 to 5. At the upper left side of
the drawing of FIG. 11 (b), a V-shaped angle (hereinafter, also referred to as a "ridge
inner angle") formed by the first surface pmiion 113 and the second surface portion
114 is illustrated.
15 [0100]
FIG. 12 is an explanatory diagram illustrating Comparative Example in
which a bending process is performed by a straight bending tool 31 without a
protrusion pmiion. FIG. 12(a) is an explanatory diagram illustrating a shape of the
bending tool 31. FIG. 12(b) is an explanatory diagram illustrating the deformation
20 state of a ridge-portion flange 115', a first flange 116', and a second flange 117' of
Comparative Examples 1 to 5. At the upper left side of the drawing of FIG. 12(b), a
V-shaped ridge inner angle formed by a first surface portion 113' and a second
surface portion 114' is illustrated.
25
[0101]
In Example 1 and Comparative Example 1, the ridge im1er angle of the
press-molded product is 60°. In Example 2 and Comparative Example 2, the ridge
38
im1er angle of the press-molded product is 70°. In Example 3 and Comparative
Example 3, the ridge inner angle of the press-molded product is 90°. In Example 4
and Comparative Example 4, the ridge inner angle of the press-molded product is
120°. In Example 5 and Comparative Example 5, the ridge inner angle of the
5 press~molded product is 150°.
[0102]
FIG. 13 is a graph in which the plate thickness increase rates of the edge
pmiions of the ridge-portion flanges 115 and 115' in the width direction are
respectively correlated with Example and Comparative Example. The vertical axis
10 indicates the maximum value of the plate thickness increase rate, and the horizontal
axis indicates the ridge im1er angle. The plate thickness increase rate indicates the
plate thickness increase rate after the bending process based on the plate thickness
(1.6mm) ofthe.blank.
[01 03]
15 As illustrated in FIGS. II (b) and 12(b ), in the press-molded products of
Examples I to 5, the plate thickness increase rate of the ridge-pmiion flange 115 is
suppressed so as to be small compared with the press-molded products having the
same ridge inner angle of Comparative Examples I to 5. Further, as illustrated in
the graph of FIG. 13, in the press-molded products of Examples I to 5, the plate
20 thickness increase rate of the ridge-pmiion flange 115 is largely suppressed
compared with the press-molded products having the same ridge inner angle of
Comparative Examples I to 5. Thus, according to the invention, it is understood
that the press-molded product having the inward continuous flange 118 with a
satisfactory shape can be produced while an increase in plate thickness of the
25 ridge-portion flange 115 is small and a difference in plate thickness distribution is
small.
39
[0104]
(Examples 6 and 7)
Next, in Example 6, a work having a V-shaped cross-section and formed by
a high-tensile steel plate with a plate thickness of 1.0 mm and a tensile strength of
5 . 980 MPa was used, and a press-molded product having an inward continuous flange
was produced according to the procedure illustrated in FIGS. 5 to 9. Further, in
Example 7, a work having a U-shaped cross-section and formed by a high-tensile
steel plate with a plate thickness of 1.0 mm and a tensile strength of 980 MPa was
used, and a press-molded product having an inward continuous flange was produced
10 according to the procedures illustrated in FIGS. 5 to 9. The plate thickness
distribution of the edge pmiion of the ridge-portion flange in the width direction
during the production of the press-molded product was analyzed by a numerical
analysis.
15
[01 OS]
FIGS. 14(a) and 14(b) are external views illustrating press-molded products
120 and 130 in which the inward continuous flanges are formed by a bending process.
FIG. 15 is a graph illustrating the plate thickness distribution in the width direction of
the edge portion of the inward continuous flange 118 formed in the end pmiion in the
extension direction of the ridge potiion 112 of the press-molded product 120 or 130.
20 In the graph of FIG. 15, the vetiical axis indicates the plate thickness increase rate
(%). Fmiher, the horizontal axis indicates the distance (mm) of the edge pmiion of
the ridge-portion flange 115.
[0106]
As illustrated in the graph of FIG. 15, according to the press-molded product
25 producing method of the invention, it is proved that the plate thickness increase rate
of a part of both sides of the center pmiion is larger than the plate thickness increase
40
rate of the circumferential center portion Rc in the edge portion of the inward
ridge-portion flange 115. Further, it is understood that the plate thickness increase
rate of the edge portion of the inward ridge-portion flange 115 is maximal at three
positions. Thus, the press-molded product producing method of the invention can
5 suppress the generation of buckling wrinkles at the circumferential center area of the
ridge-portion flange 115. Accordingly, when the press-molded product is used as,
for example, the vehicle body reinforcing member, it is possible to improve the
bonding strength between the press-molded product and the other member and to
improve the performance involved with the rigidity or the load transfer efficiency of
10 the reinforcing member.
[Reference Signs List]
[0107]
15
20
25
20 press-molding apparatus
21 a first bending tool
21 b second bending tool
22 third bending tool
23a, 23b protrusion pmiion
24 work suppmiing tool
24a support surface
24b side surface
25a, 25b shoulder portion
31 bending tool
50 drawing device
60 bending device
100, 120, 130 press-molded product
I OOA outer end portion
5
10
15
112a, 112b ridge portion
113a, 113b first surface pmiion
114 second surface pmiion
41
115, 115', liSa, llSb ridge-portion flange
115aa flat pmiion
llSab curved portion
116, 116', 116a, 116bfirstflange
117, 117' second flange
118 inward continuous flange
119 concave portion
140 work
140a longitudinal end po1iion
142a, .142b ridge pmiion
143a, 143b first surface pmiion
144 second surface portion

[Name of Document] CLAIMS
[Claim 1]
A press-molded product of a metal plate which is formed by a steel plate
having a tensile strength of 340 MPa or more and includes a ridge portion extending
5 in a predetermined direction and first and second surface pmiions respectively
extending from both ends of a ridge line formed by the ridge portion, the
press-molded product comprising:
10
an inward continuous flange in at least one end pmiion in the predetermined
direction,
wherein the inward continuous flange is obtained by continuously forming a
ridge-portion flange formed inward in an end portion of the ridge portion, a first
flange formed inward in at least a part of an area of an end pmiion of the first surface
portion, and a secand .. flange formed inward in at least a pmi of an area of an end
portion of the second surface portion, and
15 wherein regarding a plate thickness of an edge portion of the ridge-portion
20
flange, the ridge-portion flange has a plate thickness distribution in which a plate
thickness of a pmiion of each of areas on both sides of a circumferential center area
is equal to or larger than a plate thickness of the center area.
[Claim 2]
The press"molded product according to claim 1,
wherein the ridge-pmiion flange has a maximal plate thickness at three
positions of the center area and the areas on the both sides, and the plate thickness of
the positions of the areas on the both sides having a maximal plate thickness is larger
than the plate thickness of the position of the center area having a maximal plate
25 thickness.
[Claim 3]
5
10
15
43
The press-molded product according to claim 1 or 2,
wherein a flange width of at least a part of the ridge-portion flange IS
smaller than a flange width of each of the first flange and the second flange.
[Claim 4]
The press-molded product according to any one of claims 1 to 3,
wherein a flange width (Lf) of the ridge-pmiion flange and a curvature
radius (rf) of the ridge pmiion satisfY Equation (1) below:
0.2 x rf <:; Lf <:; rf... (I).
[Claim 5]
The press-molded product according to any one of claims 1 to 4,
wherein a cross-section of the press-molded product when viewed in the
predetermined direction is a substantially hat-shaped or groove-shaped opened
cross-section .or .a closed cross-section.
[Claim 6]
The press-molded product according to any one of claims I to 5,
wherein the press-molded product is a vehicle body reinforcing member.
[Claim 7]
A press-molded product producing method for a work which is formed by a
steel plate having a tensile strength of 340 MPa or more and includes a ridge portion
20 extending in a predetermined direction and first and second surface pmiions
respectively extending from both ends of a ridge line formed by the ridge pmiion, a
flange being formed in at least one end pmiion of the work in the predetermined
direction, the press-molded product producing method comprising:
an installation step of supporting an area excluding the end portion of the
25 work from an inner area of the work; and
a bending step of, using a bending tool having a protrusion portion, bringing
44
the protrusion pmiion into contact with a predetermined position of the ridge pmiion
in the end portion of the work from an outer area of the work and then relatively
moving the bending tool in a plate thickness direction of the predetermined position
in a direction toward the inner area so as to form the flange.
5 [Claim 8]
The press-molded product producing method according to claim 7,
wherein in the bending step, the flange is formed in a manner that the
protmsion portion of the bending tool presses the predetermined position of the ridge
portion in the end portion in accordance with the movement of the bending tool so as
10 to bend the predetermined position in a plate thickness direction and then a portion
other than the protrusion pmiion of the bending tool sequentially presses an other
portion excluding the predetermined position in the end pmiion so as to bend the
other portion in.a plate thickness direction.
15
[Claim 9]
The press-molded product producing method according to claim 7 or 8,
wherein the predetermined position is an area substantially having a width
of a plate thickness and including a circumferential center pmiion and both sides of
the circumferential center portion of the ridge pmiion, and
wherein the protrusion pmiion presses the predetermined position in a plate
20 thickness direction of the center potiion.
[Claim 1 OJ
A press-molded product producing apparatus comprising:
a work suppmiing tool which suppotis a work including a ridge pmiion
extending in a predetermined direction and first and second surface portions
25 respectively extending from both ends of a ridge line formed by the ridge portion
from an inner area of the work; and
45
a bending tool which relatively moves in a direction toward the inner area of
the work while contacting an end portion of the work in the predeter..m. ined direction
so as to bend the end portion in a direction toward the inner area,
wherein the bending tool includes a protrusion pmiion 1vhieh contacts a
5 predetermined position in the end portion of the ridge portion and presses the
predetermined position in a plate thickness direction of the predetermined position in
accordance with the movement.
[Claim 11]
The press-molded product producing apparatus according to claim 10,
10 wherein when the bending tool is viewed in the predetermined direction, a
width of the protrusion potiion decreases i;1 a direction toward a front end portion
and the front end pmiion forms a curve.
[Claim 12]
The press-molded product producing apparatus according to claim I 0 or 11,
15 wherein a height (h) of the protrusion potiion and a curvature radius (rf) of
the ridge pmiion satisfy Equation (2) below:
0.5 x rf :o; h :o; 3.0 x rf ... (2).