[Technical Field]
[0001]
The present invention relates to a press-formed article excellent in rigidity and
strength, which is suitably used for automotive body reinforcement member, and relates to
a press-forming method and a press-forming apparatus.
The present invention claims priority on Japanese Patent Application No.
2015-111436, filed in Japan, on June 1, 2015, which is incorporated herein by reference.
[Background Art]
[0002]
A floor of an automobile vehicle body (hereinafter, simply referred to as "floor")
is not only primary responsible for torsional rigidity and bending rigidity of the vehicle
body when the vehicle travels, but also responsible for transfer of an impact load when a
crash occurs, and further, it exerts a large influence on the weight of the automobile
vehicle body. Accordingly, for the floor, it is necessary to have antinomy characteristics
of high rigidity and light weight.
The floor includes planar panels (for example, a dash panel, a front floor panel, a
rear floor panel, and so on) which are welded to be jointed with each other, long cross
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members (for example, a floor cross member, a seat cross member, and so on) having
approximately hat-shaped cross sections which are fixed to be disposed in the vehicle
width direction of these planar panels by welding to enhance the rigidity and the strength
of the floor, and long members (a side sill, a side member, and so on) having
approximately hat -shaped cross sections which are fixed to be disposed in the forward and
rearward direction of vehicle body to enhance the rigidity and the strength of the floor.
Out of the above, the cross members are normally jointed to other members such as, for
example, a tunnel part of the front floor panel and the side sill by using outward flanges
formed at both end parts in the longitudinal direction thereof as joint margins.
[0003]
FIG. 28A to FIG. 28D are explanatory views showing a floor cross member 1,
which is a representative example of the cross member joined to the other member using
the outward flange formed on the both ends in the longitudinal direction as the joint
margm. FIG. 28A is a perspective view thereof, FIG. 28B is an A-arrow view of FIG.
28A, FIG. 28C is a B-arrow view ofF! G. 28A, and FIG. 28D is an explanatory view
enlarging a round dashed line circle section in FIG. 28B.
[0004]
For example, a front floor panel 2 is generally reinforced by the front cross
member I which joins a tunnel part (illustration is omitted) joined to an upper surface (a
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surface at an interior side) of the front tloor pane12 and formed so as to protrude at
approximately the center in the width direction of the front floor panel 2, and side sills 3
spot-welded at both side parts in the width direction ofthe front floor pane12.
The floor cross member I is jointed to the tunnel part and the side sills 3 by the spot
welding or the like by using outward flanges 4 formed at both end parts in the longitudinal
direction thereof as joint margins, thereby improving the rigidity of the floor 2 and the
load transfer characteristic when an impact load is applied.
[0005]
FIG. 29 is an explanatory view showing an outline of a conventional
press-fonning method of the floor cross member 1, and particularly enlarging a region of
the end portion oftl1e floor cross member 1 in the longitudinal direction. In FIG. 29, (a)
shows a case where press forming is performed by drawing, and (b) shows a case where,
using an expanded blank 6, press forming is performed by bending.
[0006]
In FIG. 29, (a) shows an example of a press-forming method including steps of:
forming an excessive material volume part 5a on the forming material 5 by performing
press forming by drawing; removing the excessive material volume part 5a along a cutting
line 5b; and thereafter raising the flange Sc.
In FIG. 29, (b) shows an example of a press-forming method in which an
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4
expanded blank 6 having an expanded blank shape is press formed by bending.
Note that from the point of view of the improvement of the material yield, the press
forming by bending is more preferable than the press forming by drawing which involves
the cutting of the excessive material volume part Sa.
[0007]
The press forming by drawing as shown in (a) in FIG. 29 will be supplementary
explained.
FIG. 30 is a perspective view showing a manufacturing apparatus 7 performing a
press forming by drawing as shown in (a) in FIG. 29.
(a) in FIG. 31 is a perspective view showing the manufacturing apparatus 7
before fonning, (b) in FIG. 31 is a cross sectional view showing the manufacturing
apparatus 7 before forming, and (c) in Fl G. 31 is a perspective view of the blank 8 picked
up before forming.
(d) in FIG. 31 is a perspective view showing the manufacturing apparatus 7
during forming, (e) in FIG. 31 is a cross sectional view of the manufacturing apparatus 7
during forming, and (f) in FIG. 31 is a perspective view showing the blank 8 picked up
during forming.
(g) in FIG. 31 is a perspective view showing the manufacturing apparatus 7 after
forming, (h) in FIG. 31 is a cross sectional view showing the manufacturing apparatus 7
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after forming, and (i) in FTG. 31 is a perspective view showing a press-formed article
(forming material 5).
[0008]
The manufacturing device 7 includes a punch 7-1, a blank holder 7-2, and a die
7-4 which supports a die pad which is not shown in the drawings. The blank holder 7-2
and the die pad clamps a pre-formed blank 8, and the punch 7-1 and the die 7-4 are
relatively approached each other while holding the blank holder 7-2 and the die 7-4,
whereby the press working by drawing is performed on the blank 8. As a result, a
forming material 5 with an excessive material volume part Sa is fonned.
[0009]
The floor cross member 1 is an important structural member which is responsible
for the rigidity improvement of the automobile vehicle body and transfer of the impact
load at a time of side surface crash (side impact). Accordingly, in recent years, a thinner
and higher-tensile strength steel sheet, for example, a high-tensile strength steel sheet with
a tensile strength of390 MPa or more (a high-tensile strength steel sheet so called
"high-ten") has been used as a material of the floor cross member 1, from the point of
view of reduction in the weight and improvement in crash safety. However, formability
ofthe high-tensile strength steel sheet is not good, and therefore, it is a problem that a
flexibility of design ofthe floor cross member I is low. This will be specifically
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described with reference to FIG. 28A to FIG. 28D.
[001 0]
It is desirable that the outward flange 4 at the end part in the longitudinal
direction of the floor cross member I is continuously formed so as to have a certain degree
off1ange width including a curving section 4a as indicated by a dotted line in Fig. 28D, in
order to enhance the jointing strength between the floor cross member I and the tunnel
part ofthe front floor panel2 and the side sills 3, and to enhance the rigidity ofthe floor 2
and the load transfer characteristic when the impact load is applied.
[0011]
However, when the continuous flange having the curving section 4a of the
outward flange 4 is tried to be formed through cold press forming, and the certain degree
of flange width is tried to be obtained, basically, the following failures of:
(i) stretch flange fractures at a sheet end portion of the curving section 4a of the
outward flange 4; and
(ii) wrinkling at an end portion I b in the longitudinal direction of a convex ridge
line portion l a ofthe floor cross member I and at a position from a center portion to a
vicinity of a root of the curving section 4a of the outward flange 4,
are occurred, which makes it difficult to obtain a desired shape.
These forming failures are easy to occur as a strength of steel material used for
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the floor cross member 1 is higher, and in a shape with higher stretch flange rate at the
forming of the curving section 4a of the outward t1ange 4 (namely, as a cross sectional
wall angle e in FIG. 28B and FIG. 28C is steeper).
[0012]
The floor cross member 1 tends to be high-strengthened to reduce the weight of
the automobile vehicle body. Accordingly, the cold forming ofthe continuous outward
flange 4 including the curving section 4a tends to be difficult to be enabled by the
conventional press-forming method. Accordingly, even if lowering of the rigidity in the
vicinity of the joint part ofthe floor cross member 1 with the other member and the load
transfer characteristic is accepted, due to restrictions on the press forming technology as
stated above, it is the present situation in which the occurrence of forming failures has to
be avoided by providing, to the curving sections 4a of the outward flange 4 ofthe floor
cross member I made of the high-tensile strength steel sheet, cutouts each of which is
deep to some extent that it reaches the end portion 1 b in the longitudinal direction ofthe
convex ridge line portion 1 a, as illustrated in FIG. 28A and FIG. 28B.
[0013]
Patent Documents l to 3 are not directed to a forming of the floor cross member 1,
but disclose inventions to solve a problem offailure due to the shape fixability in the
press-formed member made of the high-tensile material, by devising a pad of a forming
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tool. In these inventions, the shape fixability after the forming is improved by
intentionally generating a deflection at the blank during forming by adjusting the
positional relationship between the punch top portion and a flat pad which only faces to
the flat portion of the punch portion.
Further, Patent Document 4 discloses a teclmology for press forming a member
such as a floor cross member by bending or drawing.
[Prior Art Documents]
[Patent Documents]
[0014]
[Patent Document 1] Japanese Patent Publication No. 4,438,468
[Patent Document 2] Japanese Unexamined Patent Application, First Publication
No. 2009-255116
[Patent Document 3] Japanese Unexamined Patent Application, First Publication
No. 2012-051005
[Patent Document 4] Japanese Patent Publication No. 5,569,661
[Disclosure ofthe Invention]
[Problems to be Solved by the Invention]
[0015]
According to the results of the inventors' research, even based on the
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conventional inventions disclosed in the Patent Documents I to 3, it was diftlcult to press
form a floor cross member I which is a press-formed member made from a high-tensile
steel sheet and formed with an outward flange 4 at least from a top sheet portion to a
convex ridge line portion at an end portion in the longitudinal direction, without providing
a cutout at a curving section 4a of the outward flange 4 to a depth that enters the end
portion lb of the convex ridge line portion lain the longitudinal direction.
Further, in the conventional invention disclosed in the Patent Document 4, as a
portion corresponding to the outward flange 4 is formed by bending or drawing, it is
necessary to provide a cutout for preventing a stretch flange fracture and the wrinkles from
being occurred at this portion, as a result, countermeasures for increasing tl1e rigidity at a
portion in the vicinity of the cutout and the joint strength for joining another member.
[0016]
An objective ofthe present invention is to provide a press-formed article such as
a floor cross member without forming a cutout at the outward flange, and to provide a
press-fom1ing method and a press-forming apparatus for manufacturing the press-formed
article.
[Means for Solving tl1e Problem]
[00 17]
The gist of the present invention is as follows.
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[00 18]
(I) A first aspect of the present invention is a press-formed article including: a
top sheet portion; a sidewall continuing to the top sheet portion via a convex ridge line
portion; a flange continuing to the sidewall via a concaved ridge line portion; and an
outward flange continuing from an edge portion of the top sheet portion to an edge portion
of the flange, via an edge portion of the convex ridge line portion, an edge portion of the
sidewall, and an edge portion of the concaved ridge line portion, wherein in the same unit,
an average thickness TAve, a minimum thickness T Min, and a maximum thickness T Max of
the outward flange satisfy Equation 1 and Equation 2.
0.8 X I Ave<:: TMin < TAvc (Equation 1)
TAve < TMax <:: 1.2 X TAvc (Equation 2).
(2) The press-fanned article according to the above (1) may include a hat type
cross section having a pair of the sidewalls and a pair of the flanges.
(3) In the press-formed article according to the above(!) or (2), a material may be
a steel sheet with a tensile strength of not less than 390 MPa.
(4) In the press-fanned article according to any one of the above (I) to (3), a
minimum width of the outward flange may be not less than 12 mm.
[0019]
(5) A second aspect of the present invention is a press-forming method including:
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a shearing step that shears and deforms a workpiece in which a cross section perpendicular
to a predetermined direction has a top sheet portion, a sidewall continuing to the top sheet
portion via a convex ridge line portion, and a flange continuing to the sidewall via a
con caved ridge line portion, at a middle position viewed along the predetermined direction,
thereby forming a stepped portion continuing to all of the top sheet portion, the sidewall,
and the flange.
(6) The press-fom1ing method according to the above (5) may further include: a
removing step in which an unnecessary portion near the stepped portion is removed after
the shearing step, thereby forming an outward flange continuing from an edge portion of
the top sheet portion to an edge portion of the flange, via an edge portion of the convex
ridge line portion, an edge portion of the sidewall, and an edge portion of the concaved
ridge line portion.
(7) In the press-forming method according to the above (5) or (6), in the shearing
step, a first part in the workpiece may be restricted by a first punch and a first die, a
second part in the workpiece may be restricted by a second punch and a second die, the
first part and the second part in the workpiece being divided by the portion to be formed to
the stepped portion, and the stepped portion may be formed by relatively moving a set of
the first punch and the first die, and a set of the second punch and the second die in an
oblique direction, in a state where a clearance from the workpiece is not created.
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(8) In the press-forming method according to the above (7), an angle formed
between the oblique direction and an extending direction ofthe top sheet portion in the
cross section may be not less than 20 degrees, an angle formed between the oblique
direction and an extending direction of the sidewall in the cross section may be not less
than 20 degrees, and an angle formed between the oblique direction and an extending
direction of the flange in the cross section may be not less than 20 degrees.
[0020]
(9) A third aspect of the present invention is a press-forming apparatus that
deforms a workpiece in which a cross section perpendicular to a predetermined direction
includes a top sheet portion; a sidewall continuiug to the top sheet portion via a convex
ridge line portion; and a flange continuing to the sidewall via a concaved ridge line
portion; so as to obtain a press-formed article haviug an outward flange contiuning from
an edge portion of the top sheet portion to an edge portion of the flange, via an edge
portion of the convex ridge line portion, an edge portion of the sidewall, and an edge
portion ofthe concaved ridge line portion, the press-forming apparatus including: a first
punch and a first die that restrict a first part in the workpiece; a second punch and a second
die that restrict a second part in the workpiece, the first part and the second part iu the
workpiece being divided at a middle position in the predetermined direction; and a driving
unit that relatively moves a set of the first punch and the first die, and a set of the second
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punch and the second die in an oblique direction to form a stepped portion at the middle
position, in a state where a clearance from the workpiece is not created.
(10) In the press-forming apparatus according to the above (9), an angle formed
between the oblique direction and an extending direction of the top sheet portion in the
cross section may be not less than 20 degrees, an angle fanned between the oblique
direction and an extending direction of the sidewall in the cross section may be not less
than 20 degrees, and an angle formed between the oblique direction and an extending
direction of the flange in the cross section may be not less than 20 degrees.
[Effects of the invention]
[0021]
According to the above press-formed article, by using the outward flange formed
from the edge portion of the top sheet portion to the edge portion of the flanges, via the
edge portion of the convex ridge line portion, the edge portion ofthe sidewall, and the
edge portion of the concaved ridge line portion as a joint margin, the press-formed article
can be joined to another member. Accordingly, it is possible to enhance the rigidity in
the vicinity of the joint part ofthe press-formed article with the other member and the load
transfer characteristic. Accordingly, if the press-formed article is for example used as a
floor cross member, it is possible to improve the bending rigidity and the twisting rigidity
of the body shell, which makes it possible to improve or increase the steering stability, the
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riding comfortableness, and the noise reduction of the automobile.
[0022]
In addition, according to the press-forming method and the press-forming
apparatus as described above, the stepped portion which becomes the outward flange can
be formed by sharing deformation. Accordingly, without providing a cutout at the
outward flange for preventing the stretch flange fracture and the wrinkles from being
occurred, the above press-formed article can be successfully manufactured.
[Brief Explanation ofthe Drawings]
[0023]
FIG.! is a perspective view showing a press-formed article according to an
embodiment of the present invention.
FIG. 2A is an explanation view showing an overview of a state where an
intermediate formed article of the press-formed article is manufactured by using a
press-forming apparatus according to an embodiment of the present invention, and is a
perspective view showing a main part of the press-forming apparatus after forming a
stepped portion which becomes an outward flange.
FIG. 2B is a perspective view showing a main part ofthe intermediate formed
article formed with the stepped portion.
FIG. 2C is a perspective view showing an area in the vicinity of the outward
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flange of the press-formed article.
FIG. 2D is an A-arrow view in FIG. 2C.
FIG. 2E is an explanatory view showing factors associated with the formability of
the outward flange.
FIG. 2F is a B-arrow view in FIG. 2C.
FIG. 3 is a perspective view showing members ofthe press-forming apparatus
according to an embodiment ofthe present invention.
FIG. 4 is an explanatory view showing manufacturing of the intermediate formed
article and the press-formed article by using the press-forming apparatus according to an
embodiment of the present invention.
FIG. 5 is an explanatory view showing manufacturing of the intermediate formed
article and the press-formed article by using the press-forming apparatus according to an
embodiment of the present invention.
FIG. 6 is an explanatory view showing manufacturing of the intermediate formed
article and the press-formed article by using the press-forming apparatus according to an
embodiment of the present invention.
FIG. 7 is an explanatory view showing manufacturing of the intermediate formed
article and the press-formed article by using the press-forming apparatus according to an
embodiment of the present invention.
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16
FIG. 8A is an explanatory view showing an overview of a state where an
intermediate formed article ofthe press-formed article is manufactured by using the
press-forming apparatns according to an embodiment of the present invention, and is a
perspective view showing a main part of the press-forming apparatus after the stepped
portion, which becomes the outward flange, is formed.
FIG. 8B is a perspective view showing a main part of the intermediate formed
article formed with the stepped portion.
FIG. SC is a perspective view showing an area in the vicinity of the outward
flange ofthe press-formed article.
FIG. 8D is an A-arrow view in FIG. 8C.
FIG. 8E is a B-arrow view in FIG. SC.
FIG. 9 is a perspective view showing members ofthe press-forming apparatns
according to an embodiment of the present invention.
FIG. I 0 is an explanatory view showing manufacturing ofthe intermediate
formed article and the press-formed article by using the press-forming apparatus according
to an embodiment of the present invention.
FIG. ll is an explanatory view showing manufacturing ofthe intermediate
formed article and the press-formed article by using the press-forming apparatus according
to an embodiment of the present invention.
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17
FIG. 12 is an explanatory view showing manufacturing of the intennediate
formed article and the press-formed article by using the press-forming apparatus according
to an embodiment of the present invention.
FIG. 13 is an explanatory view showing manufacturing of the intermediate
formed article and the press-formed article by using the press-forming apparatus according
to an embodiment of the present invention.
FIG. 14 is a perspective view showing the press-formed article according to an
embodiment of the present invention.
FIG. 15A is explanatory view showing an overview of a state where an
intermediate formed article of the press-formed article is manufactured by using the
press-forming apparatus according to an embodiment of the present invention, and is a
perspective view showing a main part of the press-forming apparatus after forming the
stepped portion which becomes the outward flange.
FIG. 15B is a perspective view showing a main part of the intermediate formed
article formed with the stepped portion.
FIG. 15C is a perspective view showing an area in the vicinity of the outward
flange of the press-formed article.
FIG. lSD is an A-arrow view in FIG. 15C.
FIG. 15E is a B-arrow view in FIG. 15C.
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18
FIG. 16 is a perspective view showing members of the press-forming apparatus
according to an embodiment ofthe present invention.
FIG. 17 is an explanatory view showing manufacturing of the intermediate
formed article and the press-formed article by using the press-forming apparatus according
to an embodiment ofthe present invention.
FIG. 18 is an explanatory view showing manufacturing ofthe intermediate
formed article and the press-formed article by using the press-forming apparatus according
to an embodiment of the present invention.
FIG. 19 is an explanatory view showing manufacturing of the intermediate
formed article and the press-formed article by using the press-forming apparatus according
to an embodiment of the present invention.
FIG. 20 is an explanatory view showing manufacturing ofthe intermediate
formed article and the press-formed article by using the press-forming apparatus according
to an embodiment ofthe present invention.
Fig. 21 is a perspective view showing another example of the press-formed article
according to the present embodiment
FIG. 22A is explanatory view showing an overview of a state where an
intcnnediate formed article ofthe press-formed article is manufactured by using the
press-forming apparatus according to an embodiment of the present invention, and is a
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perspective view showing a main part ofthe press-forming apparatus after forming the
stepped portion which becomes the outward flange.
Fl G. 22B is a perspective view showing a main part of the intermediate formed
article formed with the stepped portion.
FIG. 22C is a perspective view showing an area in the vicinity ofthe outward
flange of the press-formed article.
FIG. 22D is an A-arrow view in FIG. 22C.
FIG. 22E is a B-arrow view in FIG. 22C.
FIG. 23 is a perspective view showing members of the press-forming apparatus
according to an embodiment of the present invention.
FIG. 24 is an explanatory view showing manufacturing of the intermediate
formed article and the press-formed article by using the press-forming apparatus according
to an embodiment of the present invention.
FIG. 25 is an explanatory view showing manufacturing ofthe intermediate
formed article and the press-formed article by using the press-forming apparatus according
to an embodiment of the present invention.
FIG. 26 is an explanatory view showing manufacturing of the intermediate
formed article and the press-formed article by using the press-forming apparatus according
to an embodiment of the present invention.
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20
FIG. 27 is an explanatory view showing manufacturing of the intermediate
formed article and the press-formed article by using the press-forming apparatus according
to an embodiment of the present invention.
FIG. 28A is a perspective view showing a floor cross member, which is a
representative example of the cross member joined to another member by using the
outward flange formed on the both ends in the longitudinal direction as the joint margin.
FIG. 28B is an A-arrow view ofFIG. 28A.
FIG. 28C is a B-arrow view of FIG. 28A.
FIG. 28D is an explanatory enlarged view showing a round dashed line circle
section in FIG. 28B.
FIG. 29 is an explanatory enlarged view showing an overview of conventional
press-forming method of the floor cross member, and particularly enlarging a region of the
end portion of the member in the longitudinal direction.
FIG. 30 is a perspective view showing a press-forming apparatus which perfonns
a press forming by drawing.
FIG. 31 includes (a) to (i) where (a) is a perspective view showing a
press-forming apparatus before forming, (b) is a cross sectional view showing the
press-forming apparatus before forming, (c) is a perspective view showing a blank picked
up before forming, (d) is a perspective view showing the press-forming apparatus during
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forming, (e) is a cross sectional view of the press-forming apparatus during forming, (f) is
a perspective view showing a blank picked up during forming, (g) is a perspective view
showing the press-forming apparatus after forming, (h) is a cross sectional view showing
the press-forming apparatus after forming, and (i) is a perspective view showing a blank
picked up after forming.
[Embodiments ofthe Invention]
[0024]
As a result ofthe keen studying on the solution for the above problems,
the inventors obtained the following findings (A) and (B), and accomplished the present
invention through further investigations.
[0025]
(A) It is possible to provide a desired press-formed article having an outward flange by:
performing a sharing deformation in the direction intersecting with the
longitudinal direction at a middle position in the longitudinal direction of the press-formed
body which has a cross section including a top sheet portion, a convex ridge line portion
continuing to the top sheet portion, a sidewall continuing to the convex ridge line portion,
a concaved ridge line portion continuing to the sidewall, and a flange continuing to the
concaved ridge line portion, thereby forming a stepped portion continuing to the top sheet
portion, the convex ridge line portion, the sidewall, the concaved ridge line portion, and
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22
the flange, and
removing an unnecessary portion near the stepped portion.
[0026]
(B) To form the above stepped portion in the press-formed body, a sharing deformation
of the press-formed body may be performed at a portion to be formed to the stepped
portion by:
restricting a first part in the blank by a first pnnch and a first die, and restricting a
second part in the blank by the second punch and the second die, where the first part and
the second part are divided by a portion to be formed to the stepped portion in the
longitudinal direction of the press-formed body, and
relatively moving a set of the first punch and the first die, and a set of the second
punch and the second die in the oblique direction with respect to the top sheet portion of
the press-formed body (workpiece), in a state where a clearance from the press-fonned
body is not created.
[0027]
An embodiment I for enabling the present invention and embodiments 2 to 4
which are modifications of the embodiment I will be explained with reference to the
drawings. It should be noted that in the explanations ofthe embodiments 2 to 4, a
configuration different from the embodiment I will be explained, and for a configuration
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which is explained in the embodiment 1, the same reference number in the drawing is
assigned to reduce redundant explanations.
[0028]
(I) Embodiment I
1. Press-formed article I 0 according to the present embodiment
FIG. 1 is a perspective view showing a press-formed article I 0 according to the
present embodiment.
The press-formed article 10 shown in FIG. l is a press-formed article fonned
from a high-tensile strength steel sheet (sheet thickness: 0.6 to 3.5 mm) having a tensile
strength of not less than 390 MPa, preferably not less than 590 MPa, and more preferably
not less than 980 MPa.
[0029]
The press-formed article 10 has a substantially hat type cross section including a
top sheet portion 1 I, two convex ridge line portions 12a, 12b, two sidewalls l3a, 13b, and
two con caved ridge line portions 14a, 14b, and two flanges l5a, 15b.
[0030]
In this cross section, two convex ridge line portions l2a, l2b are both continuing
to the top sheet portion 11. Each of the two sidewalls 13a, 13b continues to each ofthe
two convex ridge line portions l2a, 12b. Each of the two concaved ridge line portions
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14a, 14b continues to each of the two sidewalls 13a, 13b. In addition, each of the two
flanges l5a, 15b continues to each ofthe two concaved ridge line portions 14, 14.
[0031]
That is, the press-formed article 10 has a cross section including a top sheet
portion 11, a convex ridge line portion 12a or l2b continuing to the top sheet portion 11, a
sidewalll3a or 13b eontinuing to the convex ridge line portion l2a or 12b, a concaved
ridge line portion l4a or 14b continuing to the sidewalll3a or 13b, and a flange l5a or
15b continuing to the con caved ridge line portion 14a or 14b.
[0032]
The outward flanges 16-1, 16-2 are formed at both end portions lOA, lOB in the
longitudinal direction (the directions indicated by an arrow shown in FIG. 1) ofthe
press-formed article 10.
[0033]
Each of the outward flanges 16-1, 16-2 are continuously formed atthe edge
portion from the first flange 15a to the second flange 15b, via the first concaved ridge line
portion 14a, the first sidewall 13a, the first convex ridge line portion l2a, the top sheet
portion 11, the second convex ridge line portion 12b, the second sidewalll3b, the second
con caved ridge line portion l4b in this order.
[0034]
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The outward flanges 16-1, 16-2 satisfy the following Equation 1 and Equation2
where, in the same unit (for example, mm), T Ave is the average thickness of the outward
flange, T Min is the minimum thickness of the outward flange, and T Mox is the maximum
thickness of the outward flange.
0.8 X TAve <:: TMin < TAve (Equation 1)
[0035]
If the TMin is less than 0.8 x TAve, or the TMax is more than 1.2 x TAve, the
deviation ofthe sheet thickness in the outward flange is large, therefore, the rigidity and
the joint strength to another member may deteriorate at a portion where the sheet thickness
is locally small.
The upper limit value of the TMia and the lower limit value of the TMox should not
be particularly limited, thus, the upper limit ofthe TMin is less than TAve-
[0036]
The minimum value T Min, the maximum thickness T Max, and the average
thickness TAve of the sheet thickness of the outward flanges 16-1, 16-2 are respectively
calculated by measuring the thickness of 10 measuring points with at least 2 mm intervals,
at a central position of the outward flanges 16-1, 16-2 in the flange width direction, for
each of!he outward flanges 16-1, 16-2.
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[0037]
In the above explanations, the outward flanges 16-l, 16-2 are formed at both end
portions lOA, lOB in the longitudinal direction of the press-formed article 10 as an
example; however, the present invention is not limited only thereto. Only one of the
outward flanges 16-1 and 16-2 may be formed at the end portion lOA or lOB in the
longitudinal direction of the press-formed article 10.
[0038]
Further, in the above explanation, the outward flanges 16-1, 16-2 are
continuously formed at the edge portion from the first flange 15a to the second flange 15b
via the first concaved ridge line portion 14a, the first sidewall13a, the first convex ridge
line portion 12a, the top sheet portion 11, the second convex ridge line portion 12b, the
second sidewall13b, and the second concaved ridge line portion 14b in this order;
however, the present invention is not limited only thereto. The outward flange 16-1 or
16-2 may be formed from the first flange 15a to the top sheet portion II via the first
concaved ridge line portion 14a, the first sidewalll3a, and the first convex ridge line
portion 12a in this order, or may be formed from the first flange 15b to the top sheet
portion 11 via the second concaved ridge line portion 14b, the second sidewall l3b, and
the second convex ridge line portion l2b in this order.
[0039]
26
27
The press-formed article 10 is formed with the outward flanges 16-1, 16-2
extending from the top sheet portion II to the flanges 15a, 15b, for example in the hat
type cross section, without providing a cutout which enters into the convex ridge line
portions 12a, 12b or the concaved ridge line portions 14a, 14b at the curving section of the
outward flanges 16-1,16-2.
[0040]
According to this press-formed article 10, by using the outward flanges 16-1,
16-2 fonned at least from the top sheet portion II to the flanges !Sa, 15b in the end
portion in the longitudinal direction as a joint margin, it is possible to join this
press-formed article 10 to another member (a tunnel portion of the front tloor panel or a
side sill inner panel, if the press-formed article 10 is a cross member), therefore, it is
possible to significantly enhance the rigidity in the vicinity of the joint part of the
press-formed article 10 with the other member and the load transfer characteristic, and
further, the joint strength between the floor panel and the side sill. Therefore, for
example if the press-formed article 10 is used as a floor cross member, it is possible to
improve the bending rigidity and the twisting rigidity of the body shell, which makes it
possible to improve or increase the steering stability, the riding comfortableness, and the
noise reduction of the automobile.
[0041]
27
28
It is preferable that the minimum width of the outward flanges 16-1, 16-2 be not
less than 12 mm, so that the joint margin for joining the press-forrped article with another
member can be sufficiently secured.
The minimum width ofthe outward flanges 16-1, 16-2 is preferably not less than
15 mm and more preferably not less than 20 mm.
It should be noted that the outward flange width is a distance in the normal
direction of the concaved ridge line portion, from the concaved ridge line portion to the
end portion of the outward flange.
[0042]
2. Press-forming apparatus 20 and press-forming method according to the present
embodiment
FIG. 2A to FIG. 2F are explanatory views showing an overview of a state where
an intermediate formed article I 0-1 of the press-formed article 10 is manufactured by
using a press-forming apparatus 20 according to this embodiment. FIG. 2A is a
perspective view showing a main part of the press-forming apparatus 20 after forming the
stepped portion 16-2, which becomes the outward flange. FIG. 2B is a perspective view
showing a main part of the intermediate formed article 10-1 formed with the stepped
portion 16-2. FIG. 2C is a perspective view showing an area in the vicinity of the
outward flange 16-2 of the press-formed article 10. FIG. 20 is an A-arrow view in FIG.
28
29
2C. FIG. 2E is an explanatory view showing factors associated with the formability of
the outward flange 16-2. FIG. 2F is a B-arrow view in FIG. 2C.
[0043]
FIG. 3 is a perspective view showing members of the press-forming apparatus 20
according to this embodiment.
FIG. 4 is an explanatory view showing manufacturing of the intermediate formed
article 1 0-l and the press-formed article l 0 by using the press-forming apparatus 20
according to this embodiment.
(a) is a perspective view showing the press-forming apparatus 20 before forming
the stepped portions 16-l, 16-2 which become outward flanges, and (b) is a perspective
view showing the blank 10-2 picked up therefrom.
(c) is a perspective view showing the press-forming apparatus 20 when the
stepped portions 16-1, 16-2 are being formed, and (d) is a perspective view showing the
blank 10-2.
(e) is a perspective view showing the press-forming apparatus 20 after forming
the stepped portions 16-l, 16-2, and (f) is a perspective view showing the intermediate
formed article 1 0-l.
(g) is a perspective view showing the press-formed article I 0.
[0044]
29
30
FIG. 5 is an explanatory view showing manufacturing ofthe intermediate formed
article 10-1 and the press-formed article 10 by using the press-forming apparatus 20
according to this embodiment.
(a) is a top view showing the press-forming apparatus 20 before forming the
stepped portions 16-1, 16-2 which become the outward flanges, and (b) is a top view of
the blank 10-2 picked up therefrom.
(c) is a top view showing the press-forming apparatus 20 when the stepped
portions 16-1, 16-2 are being formed, and (d) is a top view showing the blank 10-2.
(e) is a top view showing the press-forming apparatus 20 after the stepped
portions 16-1, 16-2 are formed, and (f) is a top view showing the intermediate formed
article 10-1.
[0045]
FIG. 6 is an explanatory view showing manufacturing of the intermediate formed
article l 0-1 and the press-formed article 10 by using the press-forming apparatus 20
according to this embodiment.
(a) is a front view showing the press-forming apparatus 20 before fom1ing the
stepped portions 16-1, 16-2 which becomes the outward flange, and (b) is a front view of
the blank l 0-2 picked up therefrom.
(c) is a front view showing the press-forming apparatus 20 when the stepped
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31
portions 16-1, 16-2 are being fom1ed, and (d) is a front view showing the blank 10-2.
(e) is a front view showing the press-forming apparatus 20 after the stepped
portions 16-1, 16-2 are formed, and (f) is a front view showing the intennediate formed
article 10-I.
[0046]
Further, FIG. 7 is an explanatory view showing manufacturing of the intermediate
formed article 10-l and the press-formed article 10 by using the press-forming apparatus
20 according to this embodiment.
(a) is a side view showing the press-forming apparatus 20 before forming the
stepped portions 16-1, 16-2 which become the outward flanges, and (b) is a side view of
the blank 10-2 picked up therefrom.
(c) is a side view showing the press-forming apparatus 20 when the stepped
portions 16-l, 16-2 are being formed, and (d) is a side view showing the blank 10-2.
(e) is a side view showing the press-forming apparatus 20 after the stepped
portions 16-l, 16-2 are formed, and (f) is a side view showing the intermediate formed
article 10-l.
[0047]
As shown in FIG. 2A to FIG. 2F, and FIG. 3 to FIG. 7, the press-forming
apparatus 20 press forms the intem1ediate formed article 1 0-l of the press-formed article
31
32
10 according to this embodiment described above.
[0048]
As shown in FIG. 2A to FIG. 2F and FIG. 3 to FIG. 7, the press-forming
apparatus 20 includes a set of a first punch 24a and a first die 24b, and a set of second
punches 22a, 22b, 25a, 25d and second dies 23a, 23b, 26a, 26b.
[0049]
For preparing the press-formed body 10-2 which is a blank, a separate step may
be perfonned to preliminary fonn a product having a contour as shown in FIG. 4 (b) by
using a punch and a die. However, in view of the productivity, it is preferable to
manufacture the press-formed body 10-2 from a flat blank by using a combination punch
configured by the first punch 24a and the second punches 22a, 22b, 25a, 25b, and a
combination die configured by the first die 24b and the second dies 23a, 23b, 26a, 26b, so
as to form a contour as shown in FIG. 4 (b).
[0050]
The press-formed body l 0-2 has a hat type cross section including a top sheet
portion 11, two convex ridge line portions 12a, 12b continuing to the top sheet portion II,
two sidewalls 13a, 13b continuing to each of the two convex ridge line portions 12a, 12b,
two concaved ridge line portions 14a, 14b continuing to each of the two sidewalls 13a,
13b, and two flanges I Sa, 15b continuing to each of the two con caved ridge line portions
32
33
14a, 14b.
[0051]
The first punch 24a and the first die 24b restrict a part ofthe press-formed body
10-2 which is adjacent to a portion to be formed to the stepped portions 16-1, 16-2 which
become the outward flanges of the press-formed article 10 in the longitudinal direction.
That is, the first punch 24a and the first die 24b restrict an inside portion from the stepped
portions 16-1, 16-2.
[0052]
Meanwhile, the second punches 22a, 22b, 25a, 25b, and the second dies 23a, 23b,
26a, 26b restrict the rest portion of the press-formed body l 0-2 other than the portion to be
fonned to the stepped portions 16-1, 16-2 which become the outward flanges of the
press-formed article 10 in the longitudinal direction. That is, the second punches 22a,
22b, 25a, 25b, and the second dies 23a, 23b, 26a, 26b restrict two outside portions from
the stepped portions 16-1, 16-2.
[0053]
In addition, all of the second punch 22a, the second die 23a, the second punch
22b, the second die 23b, the second punch 25a, the second die 26a, the second punch 25b,
and the second die 26b are configured to be relatively movable in the oblique direction
with respect to the first punch 24a and the first die 24b independently while restricting the
33
34
press-formed body 10-2 without creating a clearance from the press-formed body 10-2.
More specifically, the oblique direction is the direction with an angle not less than the
tilting angle of the sidewa1113a, 13b, with respect to the top sheet portion 11 of the
press-formed body l 0-2.
[0054]
More specifically, with reference to FIG. 2E, the press direction is preferably a
direction in which all of the angles 81, 82, 83 are not less than 20 degrees.
In FIG. 2E, the reference number 11 is a height (mm) of the stepped portion 16-1
(16-2) which becomes the outward flange continuing to the top sheet portion 11, the
reference number 12 is a height (mm) of the stepped portion 16-1 (I 6-2) which becomes
the outward flange continuing to the sidewall 13a, the reference sign his a height (mm) of
the sidewall 13a, the reference sign 81 is an angle C) formed by the press direction shown
by the arrow and the extending direction of the top sheet portion 11, the reference sign 82
is an angle C) formed by the press direction shown by the arrow and the extending
direction of the sidewall I 3a, and the reference sign 83 is an angle C) formed by the press
direction shown by the arrow and the extending direction of the flange I Sa.
In addition, the reference sign 84 is an opening angle of the sidewall 13a; the
angle 84 may be not less than zero (0) degree, and preferably, the angle 84 may be not less
than 20 degrees.
34
35
[0055]
A driving unit (moving mechanism), that moves the second punch 22a, the
second die 23a, the second punch 22b, the second die 23b, the second pnnch 25a, tl1e
second die 26a, the second punch 25b, and the second die 26b with respect to the first
punch 24a and the first die 24b in this manner, is not limited to a particular driving unit.
For example, a general mechanism used as this type driving unit (such as cum-slide
mechanism or a actuator (cylinder) driving mechanism) may be used.
[0056]
Next, a press-forming method according to this embodiment will be explained.
In the press-forming method according to this embodiment, by using the press-forming
apparatus 20, the first punch 24a and the first die 24b restrict a first part ofthe
press-fonned body 10-2 which is adjacent to a portion to be formed to the stepped portion
16-1, 16-2 which becomes outward flange of the press-formed article 10 in the
longitudinal direction, tl1at is, an inside portion from the stepped portion 16-1, 16-2.
Then, while maintaining this restraining state of the press-fmmed body I 0-2 without
creating a clearance between the press-formed body 10-2 and all of the second punch 22a,
the second die 23a, the second punch 22b, the second die 23b, the second punch 25a, the
second die 26a, the second punch 25b, and the second die 26b, the press-forming
apparatus 20 moves these punches and dies independently and individually in the
35
36
relatively oblique direction with respect to the first punch 24a and the first die 24b
(sharing step). More specifically, the oblique direction is, as explained above, the
direction with an angle not less than the tilting angle of the sidewall l3a, l3b with respect
to the top sheet portion of the press-formed body 10-2.
[0057]
Accordingly, the stepped portions 16-l, 16-2 are formed by sharing deformation
at middle positions in the longitudinal direction of the press-formed body 10-2 such that
each of the stepped portion 16-1, 16-2 continues to all ofthe top sheet portion 11, two of
the convex ridge line portions l2a, l2b, two ofthe sidewalls 13a, l3b, two of the
concaved ridge line portions 14a, 14g, and two of the flanges 15a, 15b, and extends in the
direction intersecting with each of the top sheet portion 11, two of the convex ridge line
portions l2a, 12b, two of the sidewalls 13a, 13b, two of the con caved ridge line portions
14a, 14g, and two ofthe flanges 15a, 15b. As a result, the intermediate formed article
I 0-1 is manufactured.
[0058]
Thereafter, an unnecessary portion 17 near the stepped portions 16-1, 16-2 ofthe
intermediate formed article 10-1 is removed by a suitable means (for example, laser
cutting or a cum trimming), whereby the press-formed article I 0 according to this
embodiment is manufactured (removing step).
36
37
[0059]
As the stepped portions 16-1, 16-2 are formed by the sharing deformation, the
sheet thickness is substantially not reduced. Accordingly, the outward flanges 16-1, 16-2
of the press-fanned article 10 can satisfy the Equation 1 and the Equation 2 described
above where, in the same unit (for example, mm), TAve is the average thickness of the
outward flange, T Min is the minimum thickness ofthe outward flange, and T Max is the
maximum thickness of the outward flange.
[0060]
In this manner, by using the press-forming apparatus 20, a press-fanned article I 0
such as a floor cross member can be manufactured without providing a cutout in the
curving section of the outward flange 16-1, 16-2. The press-formed article 10 fanned in
this manner has a cross section including the top sheet portion 11, the convex ridge line
portion 12a or 12b continuing to the top sheet portion 11, a sidewall 13a or 13b continuing
to the convex ridge line portion I 2a or 12b, a concaved ridge line portion 14a or 1 4b
continuing to the sidewall 13a or 13b, and a flange 15a or 15b continuing to the con caved
ridge line portion l4a or !4b. In addition, the press-formed article 10 formed in this
manner has an outward flange 16-1 or 16-2 at least continuing from the top sheet portion
II to the flange !Sa or 15b at one or both ofthe two end portions 1 OA, I OB in the
longitudinal direction.
37
38
[0061]
(2) Embodiment 2
In FIG. 8A to FIG. 23 which are referred to in the following explanation, with
respect to the punch and the die, reference numbers are assigned such as
first punch 24a-l, first die 24b-l, second punches 22a-l to 3, 22b-l to 3, 25a-l to 3, 25b-l
to 3, and second dies 23a-l to 3, 23b-l to 3, 26a-l to 3, 26b-l to 3. The difference of the
number assigned after the symbol "-" means that merely the outer surface shape of the
punch or the inner surface shape of the die is modified.
[0062]
FIG. 8A to FIG. 8F are explanatory views showing an overview of a state where
an intermediate formed article 10-3 of the press-formed article 10 is manufactured by
using a press-forming apparatus 20-1 according to this embodiment. FIG. SA is a
perspective view showing a main part of the press-forming apparatus 20-1 after forming
the stepped portion 16-2 which becomes the outward flange. FIG. 88 is a perspective
view showing a main part of the intermediate formed article I 0-3 formed with the stepped
portion 16-2. FIG. 8C is a perspective view showing an area in the vicinity of the
outward flange 16-2 of the press-formed article 10. FIG. 8D is an A-arrow view in FIG.
8C. FIG. 8E is an explanatory view showing factors associated with the formability of
the outward flange 16-2. FIG. 8F is a B-arrow view in FIG. 8C.
38
39
[0063]
FIG. 9 is a perspective view showing members of the press-forming apparatus
20-1 according to this embodiment.
FIG. 10 is an explanatory view showing manufacturing of the intermediate
formed article 10-3 and the press-formed article 10 by using the press-forming apparatus
20-1 according to this embodiment.
(a) is a perspective view showing the press-forming apparatus 20-1 before
forming the stepped portions J 6-1, 16-2 which become outward flanges, and (b) is a
perspective view showing the blank 10-4 picked up therefrom.
(c) is a perspective view showing the press-forming apparatus 20-1 when the
stepped portions 16-1, 16-2 are being fonned, and (d) is a perspective view showing the
blank 10-4.
(e) is a perspective view showing the press-forming apparatus 20-1 after forming
the stepped portions 16-1, 16-2, and (f) is a perspective view showing the intermediate
formed article 10-3.
[0064]
FIG. 11 is an explanatory view showing manufacturing of the intermediate
formed article 10-3 and the press-formed article JO by using the press-forming apparatus
20-1 according to this embodiment.
39
40
(a) is a top view showing the press-forming apparatns 20-1 before forming the
stepped portions 16- I, 16-2 which become outward flanges, and (b) is a top view showing
the blank 10-4 picked up therefrom.
(c) is a top view showing the press-forming apparatus 20-1 when the stepped
portions 16-1, 16-2 are being formed, and (d) is a top view showing the blank 10-4.
(e) is a top view showing the press-forming apparatns 20-1 after forming the
stepped portions 16-1, 16-2, and (f) is a top view showing the intermediate formed article
10-3.
[0065]
FIG. 12 is an explanatory view showing manufacturing of the intennediate
formed article 10-3 and the press-formed article 10 by using the press-forming apparatus
20-1 according to this embodiment.
(a) is a front view showing the press-forming apparatus 20-1 before forming the
stepped portions 16-1, 16-2 which become outward flanges, and (b) is a front view
showing the blank 10-4 picked up therefrom.
(c) is a front view showing the press-forming apparatus 20-1 when the stepped
portions 16-1, 16-2 are being formed, and (d) is a front view showing the blank 10-4.
(e) is a front view showing the press-forming apparatus 20-1 after forming the
stepped portions I 6-1, 16-2, and (f) is a front view showing the intem1ediate fom1ed
40
41
article I 0-3.
[0066]
Further, FIG. 13 is an explanatory view showing manufacturing of the
intermediate formed article 10-3 and the press-fom1ed article I 0 by using the
press-forming apparatus 20-1 according to this embodiment.
(a) is a side view showing the press-forming apparatus 20-1 before forming the
stepped portions 16-1, 16-2 which become outward flanges, and (b) is a side view
showing the blank 10-4 picked up therefrom.
(c) is a front view showing the press-forming apparatus 20-1 when the stepped
portions 16-1, 16-2 are being formed, and (d) is a side view showing the blank 10-4.
(e) is a side view showing the press-forming apparatus 20-1 after forming the
stepped portions 16-1, 16-2, and (f) is a side view showing the intermediate formed article
10-3.
[0067]
The embodiment 2 differs from the aforementioned embodiment I in that the
fom1ing is performed such that the width ofthe top sheet portion II ofthe intermediate
formed article 10-3, fom1ed by the second punch 22a-1, the second die 23a-l, the second
punch 22b-l, the second die 23b-l, the second punch 25a-l, the second die 26a-!, the
second punch 25b-l, and the second die 26b-l, are widened as a distance from the stepped
41
42
portion 16-1, 16-2 increases. By perfom1ing the forming in this manner, when the
sharing forming ofthe stepped portions 16-1, 16-2 is performed, long cross sectional
circumferential length is preliminary secured and the cross sectional circumferential length
is reduced thereafter, the material flow toward the stepped portions 16-1, 16-2 can be
promoted. Accordingly, cracks generated at a portion where the stepped portions 16-1,
16-2 and the convex ridge line portion 12a, 12b are met can be effectively suppressed.
[0068]
(3) Embodiment 3
FIG. 14 is a perspective view showing the press-formed article 10 according to
the present embodiment.
[0069]
FIG. 15 is an explanatory view showing an overview of a state where an
intermediate formed article 10-5 of the press-formed article 10 is manufactured by using a
press-forming apparatus 20-2 according to this embodiment.
FIG. 15A is a perspective view showing a main part of the press-forming
apparatus 20-2 after forming the stepped portion 16-2 which becomes the outward flange.
FIG. l5B is a perspective view showing a main part of the intermediate formed article
10-5 fonned with the stepped portion 16-2. FIG. 15C is a perspective view showing an
area in the vicinity of the outward flange 16-2 of the press-formed article 10. FIG. 15D
42
43
is an A-arrow view in FIG. 15C. FIG. ISE is a B-arrow view in FIG. 15C.
[0070]
FIG. 16 is a perspective view showing members of the press-forming apparatus
20-2 according to this embodiment.
FIG. 17 is an explanatory view showing manufacturing of the intermediate
formed article 10-5 and the press-formed article 10 by using the press-forming apparatus
20-2 according to this embodiment.
(a) is a perspective view showing the press-forming apparatus 20-2 before
forming the stepped portions 16-1, 16-2 which become outward flanges, and (b) is a
perspective view showing the blank 10-6 picked up therefrom.
(c) is a perspective view showing the press-forming apparatus 20-2 when the
stepped portions 16-1, 16-2 are being formed, and (d) is a perspective view showing the
blank 10-6.
(e) is a perspective view showing the press-forming apparatus 20-2 after forming
the stepped portions 16-1, 16-2, and (f) is a perspective view showing the intermediate
formed article 10-5.
[0071]
FIG. 18 is an explanatory view showing manufacturing of the intermediate
fonned article 10-5 and the press-formed article 10 by using the press-forming apparatus
43
44
20-2 according to this embodiment.
(a) is a top view showing the press-forming apparatus 20-2 before forming the
stepped portions 16-1, 16-2 which become outward flanges, and (b) is a top view showing
the blank 10-6 picked up therefrom.
(c) is a top view showing the press-forming apparatus 20-2 when the stepped
portions 16-1, 16-2 are being formed, and (d) is a top view showing the blank 10-6.
(e) is a top view showing a press-forming apparatus 20-2 after forming the
stepped portions 16-1, 16-2, and (f) is a top view showing the intermediate fom1ed article
10-5.
[0072]
FIG. 19 is an explanatory view showing manufacturing ofthe intermediate
formed article 10-5 and the press-formed article 10 by using the press-forming apparatus
20-2 according to this embodiment.
(a) is a front view showing the press-forming apparatus 20-2 before forming the
stepped portions 16-1, 16-2 which become outward flanges, and (b) is a front view
showing the blank 10-6 picked up therefrom.
(c) is a front view showing the press-forming apparatus 20-2 when the stepped
portions 16-J, 16-2 are being formed, and (d) is a front view showing the blank 1 0-6.
(e) is a front view showing the press-forming apparatus 20-2 after forming the
44
45
stepped portions 16-1,16-2, and (f) is a front view showing the intermediate formed
artiele I 0-5.
[0073]
FIG. 20 is an explanatory view showing manufacturing of the intennediate
formed article 10-5 and the press-formed article 10 by using the press-forming apparatus
20-2 according to this embodiment.
(a) is a side view showing the press-forming apparatus 20-2 before forming the
stepped portions 16-l, I 6-2 which become outward flanges, and (b) is a side view
showing the blank 10-6 picked up therefrom.
(c) is a side view showing the press-forming apparatus 20-2 when the stepped
portions 16-1, 16-2 are being formed, and (d) is a side view showing the blank 10-6.
(e) is a side view showing the press-forming apparatus 20-2 after forming the
stepped portions 16-1, 16-2, and (f) is a side view showing the intermediate formed article
I 0-5.
[0074]
The embodiment 3 differs from the aforementioned embodiment 1 in that the
fonning is performed such that the radius of curvature of the convex ridge line portions
12a, 12b of the intermediate formed article 10-3, formed by the second punch 22a-2, the
second die 23a-2, the second punch 22b-2, the second die 23b-2, the second punch 25a-2,
45
46
the second die 26a-2, the second punch 25b-2, and the second die 26b-2, becomes larger
than the radius of curvature of the convex ridge line portions 12a, 12b of the intermediate
fonned article 10-3 restricted by the first punch 24a and the first die 24b.
By perfonning the fanning in this manner, when the sharing forming of the
stepped portions 16-1, 16-2 is performed, the cross sectional circumferential length
difference and the projecting shape are alleviated and thus the material flow toward the
stepped portions 16-1, 16-2 is promoted. Accordingly, cracks generated at a portion
where the stepped portions 16-1, 16-2 and the convex ridge line portion 12a, 12b are met
(a stretch flange fanning portion) can be effectively suppressed.
[0075]
(4) Embodiment 4
FIG. 2 J is a perspective view showing a press-formed article 30 according to the
present embodiment.
[0076]
FIG. 22 is an explanatory view showing an overview of a state where an
intennediate formed article I 0-7 of the press-fonned article 30 is manufactured by using a
press-fanning apparatus 20-3 according to this embodiment.
FIG. 22A is a perspective view showing a main part of the press-forming
apparatus 20-3 after forming the stepped portion 16-2 which becomes the outward tlange.
46
47
FIG. 22B is a perspective view showing a main part of the intennediate fonned article
I 0-7 formed with the stepped portion 16-2. FIG. 22C is a perspective view showing an
area in the vicinity of the outward flange 16-2 of the press-formed article 30. FIG. 22D
is an A-arrow view in FIG. 22C. FIG. 22E is a B-arrow view in FIG. 22C.
[0077]
FIG. 23 is a perspective view showing members of the press-fonning apparatus
20-3 according to this embodiment.
FIG. 24 is an explanatory view showing manufacturing of the intennediate
fonned article 10-7 and the press-formed article 30 by using the press-forming apparatus
20-3 according to this embodiment.
(a) is a perspective view showing a blank 10-8 picked up before fonning the
stepped portions 16-1, 16-2 which become the outward flanges. (b) is a perspective view
showing the blank 10-8 when the stepped portions 16-1, 16-2 are being formed. (c) is a
perspective view showing an intennediate fonned article I 0-7 after forming the stepped
portions 16-1, 16-2. (d) is a perspective view ofthe press-formed article 30.
[0078]
FIG. 25 is an explanatory view showing manufacturing of an intermediate formed
article 10-7 and a press-formed article 30 by using the press-forming apparatus 20-3
according to this embodiment.
47
48
(a) is a top view showing a blank 10-8 picked up before forming the stepped
portions 16-1, I 6-2 which become the outward flanges.
(b) is a top view showing the blank 10-8 when the stepped portions 16-1, 16-2 are
being formed.
(c) is a top view showing the intermediate formed article 10-7 after forming the
stepped portions 16-1, 16-2.
[0079]
FIG. 26 is an explanatory view showing manufacturing of an intermediate formed
article 10-7 and a press-formed article 30 by using the press-forming apparatus 20-3
according to this embodiment.
(a) is a front view showing a blank 10-8 picked up before fom1ing the stepped
portions 16-J , 16-2 which become the outward flanges.
(b) is a front view showing the blank 10-8 when the stepped portions 16-1, 16-2
are being formed.
(c) is a front view showing the intermediate formed article I 0-7 after forming the
stepped portions 16-1, I 6-2.
[0080]
FIG. 27 is an explanatory view showing manufacturing ofthe intermediate
formed article 10-7 and the press-formed article 30 by using the press-forming apparatus
48
49
20-3 according to this embodiment.
(a) is a side view showing the blank 10-8 picked up before forming the stepped
portions 16-1, 16-2 which become the outward flanges.
(b) is a side view showing the blank I 0-8 when the stepped portions 16- J, I 6-2
are being formed.
(c) is a side view showing the intermediate formed article 10-7 after forming the
stepped portions 16-1, 16-2.
[0081]
The embodiment 4 is basically similar to the embodiment 1, but differs in that a
recessed portion 18 is formed on a top sheet portion 11 and sidewalls 13~ 13b of the
pre-formed blank 10-8, and an upward protruding portion 19 is formed on the flanges 15a,
15b, whereby the press-formed article 30 is formed with the recessed portion 18 at the top
sheet portion 11 and the sidewalls l3a, 13b, and the upward protruding portion 19 at the
flanges !Sa, 15b.
[0082]
Specific examples of the present invention have been explained above based on
various embodiments and modifications, but the present invention should not be only
limited to these exemplary embodiments. The present invention includes various
modifications of the above specific examples.
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[0083]
In the above explanation, as an example, a steel sheet is used as a blank (sheet
material). However, the blank may be a plated steel sheet such as a galvanized steel
sheet or a galvannealed steel sheet, or may be a metallic sheet such as an aluminum sheet
or a titanium steel sheet, or a glass fiber strengthen resin sheet such as FRP or FRTP, or a
composite sheet thereof.
In the above explanation, the press-formed article has a pair of outward flanges as
an example. However, the press-formed article may be tormed with only one outward
flange.
In addition, in the above explanation, the press-formed article has a cross section
including a pair of convex ridge line portions, a pair of sidewalls, a pair of con caved ridge
line portions, and a pair of flanges, as an example. However, the press-fonned article
may have a half-hat type cross section including respectively one of the convex ridge line
portion, the sidewall, the concaved ridge line portion, and the flange. ln addition, the
press-formed article having the half-hat type cross section may be formed with only one
outward flange.
In the above explained press-formed article, as an example, an angle fonned by
the plane direction of the stepped portion or the outward flange and the plane direction of
the top sheet portion is larger than 90 degrees. However, the angle may be not larger
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51
than 90 degrees.
[0084]
(Examples)
From press-formed bodies l 0-2 having a contour as shown in FIG. 4 (b),
press-formed articles 10 having a contour as shown in FIG. I are manufactured. As
comparative examples, a press-forming apparatus (manufacturing device 7) as shown in
FIG. 30 is used for performing draw forming. As examples of the present invention, a
press-forming apparatus 20 as shown in FIG. 3 is used for performing sharing fonning.
[0085]
Table 1 collectively shows the tensile strength IS of the press-formed body 10-2,
the sidewall angle e as shown in FIG. 3, and the evaluation result of the formability. It
should be noted that in the "formability evaluation", GOOD indicates that the forming is
successfully performed without generation a crack, and BAD indicates that the forming is
unsuccessfully performed due to the generation of a crack.
51
[0086]
[Table 1]
TS (MPa)
Method
Sidewall angle 8 C)
Comparative examples
590 780 980
Draw forming
112.5
Evaluation of the fonnability I BAD BAD BAD
52
1180 1310 1410
135
BAD BAD BAD
--- --L_
52
Examples of the present invention
590 780 980 1180 1310 1410
I
Sharing fanning
112.5 135
GOOD GOOD GOOD GOOD GOOD GOOD
-·L_ ...... - - L__ .. - .
53
[0087]
As shown in FIG. 1, in the comparative examples, if the tensile strength of the
press-formed body 10-2 exceeds 440 MPa, a crack was generated at a portion where the
outward flanges 16-1, 16-2 and the convex ridge line portions 12a, 12b are met, and
therefore failed to manufacture the press-formed article 10 having the outward flanges
16-1, 16-2. On the other hand, in the examples of the present invention, even if the
tensile strength of the press-formed body 10-2 exceeds 590 MPa, no crack was generated
at the portion where the outward flanges 16-1, 16-2 and the convex ridge line portions 12a,
12b are met, and the desired press-formed article 10 was successfully manufactured.

Claims
I. A press-formed article comprising:
a top sheet portion;
a sidewall continuing to the top sheet portion via a convex ridge line portion;
a flange continuing to the sidewall via a concaved ridge line portion; and
an outward flange continuing from an edge portion of the top sheet portion to an
edge portion of the ±1ange, via an edge portion of the convex ridge line portion, an edge
portion ofthe sidewall, and an edge portion of the concaved ridge line portion, wherein
in a same unit, an average thickness TAve, a minimum thickness T Min, and a
maximum thiclmess TMax of the outward flange satisfy Equation 1 and Equation 2,
0.8 X TAve <:: TMin < TAve (Equation 1),
TAve < TMax <:: 1.2 X TAve (Equation 2).
2. The press-formed article according to claim 1, comprising a hat type cross section
having a pair of the sidewalls and a pair ofthe flanges.
3. The press-formed article according to claim 1 or 2, wherein a material is a steel sheet
with a tensile strength of not less than 390 MPa.
4. The press-formed article according to any one of claims l to 3, wherein
a minimum width ofthe outward flange is not less than 12 mm.
5. A press-fanning method comprising:
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a shearing step that shears and deforms a workpiece in which a cross section
perpendicular to a predetermined direction has a top sheet portion, a sidewall continuing
to the top sheet portion via a convex ridge line portion, and a flange continuing to the
sidewall via a concaved ridge line portion, at a middle position viewed along the
predetermined direction, thereby forming a stepped portion continuing to all of the top
sheet portion, the sidewall, and the flange.
6. The press-forming method according to claim 5, further comprising:
a removing step in which an unnecessary portion near the stepped portion is
removed after the shearing step, thereby forming an outward flange continuing from an
edge portion of the top sheet portion to an edge portion of the flange, via an edge portion
of the convex ridge line portion, an edge portion of the sidewall, and an edge portion of
the concaved ridge line portion.
7. The press-forming method according to claim 5 or 6, wherein in the shearing step,
a first part in the workpiece is restricted by a first punch and a first die,
a second part in tbe workpiece is restricted by a second punch and a second die,
the first part and the second part in the workpiece being divided by a portion to be formed
to the stepped portion, and
the stepped portion is formed by relatively moving a set ofthe first punch and the
first die, and a set ofthe second punch and the second die in an oblique direction, in a state
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where a clearance from the workpiece is not created.
8. The press-forming method according to claim 7, wherein
an angle formed between the oblique direction and au extending direction of the
top sheet portion in the cross section is not less than 20 degrees,
an angle formed between the oblique direction and an extending direction of the
sidewall in the cross section is not less than 20 degrees, and
an angle formed between the oblique direction and an extending direction of the
flange in the cross section is not less than 20 degrees.
9. A press-forming apparatus that deforms a workpiece in which a cross section
perpendicular to a predetermined direction includes a top sheet portion; a sidewall
continuing to the top sheet portion via a convex ridge line portion; and a flange continuing
to the sidewall via a concaved ridge line portion; so as to obtain a press-formed article
having an outward flange continuing from an edge portion of the top sheet portion to an
edge portion of the flange, via an edge portion of the convex ridge line portion, an edge
portion ofthe sidewall, and an edge portion ofthe concaved ridge line portion, the
press-forming apparatus comprising:
a first punch and a first die that restrict a first part in the workpiece;
a second punch and a second die that restrict a second part in the workpiece, the
first part and the second part in the workpiece being divided at a middle position in the
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predetennined direction; and
a driving unit that relatively moves a set of the first punch and the first die, and a
set of the second punch and the second die in an oblique direction to fonn a stepped
portion at the middle position, in a state where a clearance from the workpiece is not
created.
10. The press-fonning apparatus according to claim 9, wherein
an angle fanned between the oblique direction and an extending direction of the
top sheet portion in the cross section is not less than 20 degrees,
an angle fanned between the oblique direction and an extending direction of the
sidewall in the cross section is not less than 20 degrees, and
an angle fonned between the oblique direction and an extending direction of the
flange in the cross section is not less than 20 degrees.