Description
Title of Invention
METHOD OF MANUFACTURWG PLATE-LIKE MOLDED BODY HAVING A
5 PLURALITY OF THICKENED PORTIONS, AND PLATE-LIKE MOLDED BODY
HAVING A PLURALITY OF THICKENED PORTIONS
Technical Field
[OOOl]
10 The present invention relates to a method of manufacturing a plate-like
molded body having a plurality of thickened portions, and particularly relates to a
method including a step of molding a plate-like molded body by press processing.
Background Art
15 [0002]
Some plate-like members used in transport airplanes, construction
structures, and the like are fastened to other members with bolts. FIG. 1 is a plan
view illustrating an example of a plate-like member having a plurality of fastening
portions. This plate-like member 1 has a substantially flat circular plate shape.
20 The plate-like member 1 includes three fastening portions 2 in a region spaced apart
from the margin. The plate-like member 1 is bolted to another member at the
fastening portions 2.
[0003]
When the surface of the plate-like member 1 serves as the bearing surface of
25 the bolts, the fastening strength is influenced by the thickness around the fastening
portions 2 of the plate-like member 1 to a large extent. When the fastening strength
is required to be increased, it is necessary to either increase the thickness of the platelike
member 1 or to attach a reinforcing plate to the fastening poi-tions 2.
[0004]
30 Howevel; when the thickness of the whole of the plate-like member is
increased, the weight of the plate-like member markedly increases. When a product
including the plate-like lncmber is demanded to be decreased in weight, such demand
cannot be satisfied. Furthermore, the use of the reinforcing plate increases the
number of components, thereby raising the costs of management and assembling.
To address these concerns, it is conceivable that only a necessary portion (in the
5 example of FIG. 1, the fastening portions 2 and portions around the fastening
portions 2) of the plate-like member is increased in thickness (hereinafter, also
referred to as "thickened").
[0005]
Patent Literature 1 discloses a thickening press process including: a
10 previous step of deep-drawing a work; and a step of pressing the deep-drawn work to
thicken a predetermined portion. Patent Literature 2 discloses a method of
clamping a pressed work having an end wall and a bent portion that is bent from the
outer circumference toward one side, at the bent portion from the outer
circumference of this end wall, so that the bent portion is compressed in the radial
15 direction for thickening. Patent Literature 3 discloses a method of manufacturing a
molded component having a bent corner, including a thickening step of increasing in
thickness of a comer by molding under pressure.
Citation List
20 Patent Literature
[0006]
Patent Literature 1 : JP 3594845B
Patent Literature 2: JP 2010-247199A
Patent Literature 3: JP 2007-175765A
Summary of Invention
Technical Problem
[0007]
However, the methods disclosed in Patent Literatures 1 to 3 are intended to
30 thicken a bent pol-tion or a portion adjacent to an edge in a plate-like member.
Therefore, these methods cannot be applied to other portions, for example, when a
region spaced apart from a margin is thickened in a substantially flat plate-like
portion (that is, an unbent portion), like the fastening poitions 2 illustrated in FIG. 1.
In addition, Patent Literatures 1 to 3 do not indicate a method of thickening a
plurality of regions (fastening portions and portions around the fastening portions)
5 along a circumferential direction with respect to a centel; like the plate-like member
1 illustrated in FIG. 1.
[OOOS]
The present invention has been devised in view of the above-described
problems. An object of the present invention is to provide a novel and improved
10 plate-like molded body having a thickened portion in a region spaced apart from an
edge in a substantially flat plate-like portion, and a method of manufacturing the
plate-like molded body.
Advantageous Effects of Invention
15 [0009]
In order to solve the above problems, according to an aspect of the present
invention, there is provided a method of manufacturing a plate-like molded body
having a plurality of thickened portions, including at least a drawing step of
obtaining by a drawing process a cylindrical drawn molded body including a flat
20 plate portion and a cylindrical drawn portion that swells in such a manner as to
project from the flat plate portion and has a circular top portion. The drawing step
includes a first step of pressing a region spaced apart from an edge in a plate-like
member having a flat plate shape, with a first mold and a second mold, to form a
concave curved portion in the plate-like member, and a second step of holding an
25 outer circumferential section of the plate-like member between a third mold and a
fourth hold while a region containing the concave curved portion in the plate-like
lneinber is held between the first mold and the second mold, and tnoving the first
nlold and the second inold relative to the third mold and the fourth mold to cause the
region containing the concave curved portion to project with respect to the outer
30 circumferential section and to obtain the cylindrical drawn molded body.
[OOlO]
Thc first step may include forming thc concave curved portion in a region
corresponding to the top portion, and the sccond step may include sctting a plurality
of thickening target regions containing at least a part of the concave curved portion
along a circumferential direction with respect to a speciiic center in a region
5 corresponding to the cylindrical drawn portion, and performing a drawing proccss
such that in a cross section that is vertical to the flat plate portion and contains the
specific center, an actual length of the thickening targct region becomes longer than
an actual length of the thickened portion in the plate-like molded body.
[OOll]
10 The method may further include, after the drawing step, a thickening step of
pressing the cylindrical drawn molded body such that an actual lenglh of each of the
thickening target regions in the cross section decreases, and the thickening target
region and the flat plate portion finally become flat as a whole.
[OO 121
15 The concave curved portion may include a hole-like curved portion that is
curved in a hole shape.
[0013]
The concave curved portion may further include a ring groove-like curved
portion that is curved in a groove shape and formed around the hole-like curved
20 portion in such a manner as to have a polygonal shape as a whole when seen
vertically to the flat plate portion.
[00 141
The concave curved portion may include a ring groove-like curved portion
that is curved in a groove shape and formed in such a manner as to have a polygonal
25 shape as a whole when seen vertically to the flat plate portion.
[OO 151
The thickened portion may have a plate thickness with a thickening rate of
20% or more with respect to an initial plate thickness as a plate thickness of the
cylindrical drawn molded body, and may have a length of five times or more the
30 initial plate thickness in the cross section.
[00 1 61
In order to solve the above problems, according to another aspect of the
present invention, there is provided a plate-like molded body having a plurality of
thickened portions, including a flat plate portion, and a cylindrical drawn portion that
swells in such a manner as to project from the flat plate portion and has a circular top
5 portion. When t [mm] is a standard plate thickness, a plate thickness ti [mm] of the
thickened portion and a plate thickness td [mm] of a thinlled portion having a smaller
thickness than the standard plate thickness satisfy relational formulas below:
when2.0 1.25t,
when 3.0 i t < 4.0, td 2 0.9t, ti 2 1.351, and
10 when4.0.:t0.9t,ti~1.4St.
[OO 171
As described above, according to the present invention, there can be
provided a plate-like molded body having a thickened portion in a region spaced
apart from an edge in a substantially flat plate-like portion, and a method of
15 manufacturing the plate-like molded body.
Brief Description of Drawings
[0018]
[FIG. 11 FIG. 1 is aplan view illustrating an example of a plate-like member.
20 [FIG. 21 FIG. 2 is a perspective view of a cylindrical drawn molded body formed and
used in a first embodiment.
[FIG. 3A] FIG. 3A is a cross-sectional view for explaining a drawing step in the first
embodiment.
[FIG. 3B] FIG. 3B is a cross-sectional view for explaining the drawing step in the
25 first embodiment.
[FIG 3C] FIG. 3C is a cross-sectional view for explaining the drawing step in the
first embodiment.
[FIG. 3D] FIG. 3D is a cross-sectional view for explaining the drawing step in the
first embodiment.
30 [FIG. 4A] FIG. 4A is a cross-sectional view for explaining a step of deforming a
cylindrical drawn portion in such a manner as to be gathered toward a central axis
side and thickening a poi-tion around a concave curved portion in the first
embodiment.
[FIG. 4B] FIG. 4B is a cross-sectional view for explaining the step of defoiming the
cylindrical drawn portion in such a manner as to be gathered toward the central axis
5 side and thickening the portion around the concave curved portion in the first
embodiment.
[FIG. 4C] FIG. 4C is a cross-sectional view for explaining the step of deforming the
cylindrical drawn portion in such a manner as to be gathered toward the central axis
side and thickening the poi?ion around the concave curved portion in the first
10 embodiment.
[FIG. 4D] FIG 4D is a cross-sectional view for explaining the step of deforming the
cylindrical drawn portion in such a manner as to be gathered toward the central axis
side and thickening the portion around the concave curved portion in the first
embodiment.
15 [FIG. 5A] FIG. 5A is a cross-sectional view for explaining a main thickening step in
the first embodiment.
[FIG. 5B] FIG. 5B is a cross-sectional view for explaining the main thickening step in
the first embodiment.
[FIG. 5CJ FIG. 5C is a cross-sectional view for explaining the main thickening step in
20 the first embodiment.
[FIG. 5D] FIG. 5D is a cross-sectional view for explaining the main thickening step
in the first embodiment.
[FIG. 6A] FIG. 6A is a cross-sectional view for explaining a step of adjusting the
thickness of a thickening target region in the first embodiment.
25 [FIG. 6B] FIG. 6B is a cross-sectional view for explaining the step of adjusting the
thickness of the thickening target region in the first embodiment.
[FIG. 6C] FIG. 6C is a cross-sectional view for explaining the step of adjusting the
thickness ofthe thickening target region in the first embodiment.
[FIG. 6D] FIG. 6D is a cross-sectional view for explaining the step of adjusting the
30 thickness of the thickening target region in the first embodiment.
[FIG. 71 FIG. 7 is a perspective view of a cyliildrical drawn molded body formed and
used in a second embodiment.
[FIG. 8A] FIG. 8A is a cross-sectional view for explaining a drawing step in the
second embodiment.
[FIG. 8B] FIG. 8B is a cross-sectional view for explaining the drawing step in the
5 second embodiment.
[FIG. 8C] FIG. 8C is a cross-sectional view for explaining the drawing step in the
second embodiment.
[FIG. 8D] FIG. 8D is a cross-sectional view for explaining the drawing step in the
second embodiment.
10 [FIG. 9A] FIG. 9A is a cross-sectional view for explaining a step of deforming a
cylindrical drawn portion in such a manner as to be gathered toward a central axis
side and thickening a portion around a concave curved portion in the second
embodiment.
[FIG. 9B] FIG. 9B is a cross-sectional view for explaining the step of deforming the
15 cylindrical drawn portion in such a manner as to be gathered toward the central axis
side and thickening the portion around the concave curved portion in the second
embodiment.
[FIG. 9C] FIG. 9C is a cross-sectional view for explaining the step of deforming the
cylindrical drawn portion in such a manner as to be gathered toward the central axis
20 side and thickening the portion around the concave curved portion in the second
embodiment.
[FIG. 9D] FIG. 9D is a cross-sectional view for explaining the step of deforming the
cylindrical drawn portion in such a manner as to be gathered toward the central axis
side and thickening the portion around the concave curved portion in the second
25 embodiment.
[FIG. 101 FIG. 10 is a characteristics diagram illustrating a relationship between a
standard plate thickness t [mnl] of a cylindrical drawn molded body, a plate thickness
ti [mm] of a thickened portion, and a plate thickness td [mm] of a thinned portion
having been thinned compared to the standard plate thickness.
30
Description of Embodiments
[00 191
Hereinafter, preferred embodiments of the present invention will be
described in detail with reference to the appended drawings. Note that, in this
specification and the appended drawings, structural elements that have substantially
5 the same function and jtructure are denoted with the same reference numerals, and
repeated explanation of these structural elements is omitted.
[002O]
A method of manufacturing a plate-like molded body having a plurality of
thickened portions according to the present embodiments includes a drawing step and
10 a thickening step.
The drawing step is to obtain by a drawing process a cylindrical drawn
molded body including a flat plate portion and a cylindrical drawn portion that swells
in such a manner as to project fkom the flat plate portion and has a circular top
portion. The drawing step includes: forming, in a region corresponding to the top
15 portion, a concave curved portion containing a hole-like curved poi-tion that is curved
in a hole shape; setting a plurality of thickening target regions containing at least part
of the concave curved portion along a circumferential direction with respect to a
specific center in a region corresponding to the cylindrical drawn portion; and
performing a drawing process such that an actual length of the thickening target
20 region in a cross section that is vertical lo the flat plate portion and contains ihe
specific center becomes longer than an actual length of the thickened portion in the
plate-like molded body.
The thickening step includes pressing the cylindrical drawn molded body
such that an actual length of each of the thickening target regions in the cross section
25 decreases, and the thickening target regions and the flat plate portion finally become
flat as a whole.
[0021]
Here, the "actual length" indicates a length along a surface of an object in a
prescribed cross section of the object.
30 100221
The thickening step may include a plurality of steps for pressing ihe
cylindrical drawn molded body such that the actual lcngtll of each of the thickening
target regions in the cross section decreases. In this case, the thickening target
regions and the flat plate portion can be made in a flat state as a whole in at least one
of these steps.
5 [0023]
The material of the plate-like member is not particularly limited, but can be,
for example, a high tensile steel plate having a tensile strength of 390 MPa or more.
For example, the high tensile steel plate may have a tensile strength of 440 MPa or
more.
10 [0024]
The plate-like molded body manufactured by this manufacturing method
can be used as, for example, a drive train component and a suspension attachment
part. In this case, the thickened portions can serve as a portion to which a bolt is
fastened.
15 [0025]
Hereinafter, embodiments of the present invention will be described with
reference to the drawings.

. In this embodiment, there is manufactured a plate-like molded body
20 including three thickened portions formed around a center, such as a plate-like
member 1 illustrated in FIG. 1 in which fastening portions 2 and portions around the
fastening portions 2 are thickened.
[0026]
FIG. 2 is a perspective view of a cylindrical drawn molded body hrmed in a
25 drawing process. As illustrated in FIG. 2, a cylindrical drawn molded body 5
obtained in this step includes a flat plate portion 6 and a cylindrical drawn portion 7
that swells in such a manner as to project with respect to the flat plate portion 6.
[0027]
In this embodiment, the cylindrical drawn portion 7 has a dome-like shape,
30 and is approximately circular when seen vertically to the flat plate poi-tion 6. The
cplindrical drawn portion 7 includes a ring-shapcd side portion 7a that rises from the
flat plate portion 6, and a circular top portion 7b. The top portion 7b includes a
concave curved portion 10 having a hole-like curved portion 8 that is curved in a
hole shape and a ring groove-like curved portion 9 that is formed around the holelike
curved portion 8 and curved in a groove shape.
5 [0028]
The ring groove-like curved portion 9 approximately has a shape of an
equilateral triangle when seen vertically to the flat plate portion 6. In this
embodiment, the foimed ring groove-like curved portion 9 has a shape of a triangle
corresponding to formation of thee thickened portions. When N thickened portions
10 are formed, a ring groove-like curved portion having an N-angular shape is formed.
Although the ring groove-like curved portion 9 formed around the hole-like curved
8 has a single groove (one groove) in this embodiment, the ring groove-like
curved portion 9 may have double or more grooves.
[0029]
15 FIG. 3A to FIG. 3D are each a cross-sectional view for explaining the
drawing step. In this step, a lower die (blank holder) 11 and a punch 12 as well as
an upper die 13 and a pad 14 that are paired with and disposed above the lower die
11 and the punch 12 are used for press molding (a drawing process) to obtain the
cylindrical drawn molded body 5 as an intermediate molded body.
20 [0030]
In each of the following cross-sectional views (FIG. 3B, FIG. 3C, FIG. 4A to
FIG. 4C, FIG. 5A to FIG. 5C, FIG. 6B, FIG. 6C, FIG. 8B, FIG. 8C, and FIG. 9A to
FIG. 9C), an arrow indicates a moving direction of a mold.
1003 11
25 A cylindrical hole penetrating in the vertical direction is formed in thc lower
die 11. The punch 12 is arranged in this hole. Thc relative positional relationship
between the lower die 11 and the punch 12 is changed by the movement of the lower
die 11 in the vertical direction. The upper surfaces of the lower die 11 and thc
punch 12 constitute a pressing surface 1 la and a press surface 12a, respectively.
30 [0032]
A columnar hole extending in the vci-tical direction and having a width
smaller than the hole of the lower die 11 is formed in the upper die 13. The pad 14
is arsangcd in this hole and attached to the upper die 13 via a press spring or a gas
cylinder, and is movable along the axial direction of this hole.
[0033]
5 Of the lower surface of the upper die 13, the outer circumferential section
constitutes a pressing surface 13a and faces the pressing surface l l a of the lower die
11, and the inner circumferential section constitutes a press surface 13b and faces the
outer circumferential section of the press surface 12a of the punch 12. The lower
surface of the pad 14 constitutes a press surface 14a and faces the central section of
10 the press surface 12a of the punch 12. A load is applied to the pad 14 from the
upper die 13 via a press spri,ng or a gas cylinder. While such a load is not applied,
the lower end of the pad 14 is positiolled slightly lower than the height of the
pressing surface 13a.
[0034]
15 The pressing surface l l a of the lower die 11 and the pressing surface 13a of
the upper die 13 are flat. The press surface 14a of the pad 14 and a region facing
the press surface 14a in the press surface 12a of the punch 12 have a shape
corresponding to the concave curved portion 10 (see FIG. 2) of the cylindrical drawn
molded body 5. The press surface 13b and a region facing the press surface 13b in
20 the press surface 12a have a shape corresponding to a portion other than the concave
curved portion 10 in the cylindrical drawn poi-tion 7.
[0035]
With reference to FIG. 3A, the height of the pressing surface l l a of the
lower die 11 and the height of the upper end of the press surface 12a of the punch 12
25 are first aligned to be approximately the same. Then, for example, a plate-like
member (hereinafter, also referred to as "work") W having a flat plate shape as a
body to be processed is placed on the pressing surface 11 a and the press surface 12a.
[0036]
Next, the work W is held between the lower die 11 and the upper die 13
30 with a cushion force in the case of a single-acting press machine and with an acted
outer load in the case of a double-acting press machine (a single-acting press
machine in the drawing). At this time, the lower die 11 and the upper die 13 applies
a force in an in-plane direction (referred to as "blank holding force" or "wrinkle
suppressing force") to the work W to a degree that allows the work W to move.
[0037]
5 Subsequently, the upper die 13 is moved downward. This allows the pad
14 attached to the upper die 13 to also move downward, and causes the lower end of
the upper die 13 to be firstly brought into contact with the work W. .Then, the upper
die 13 is further moved downward, so that the work W is pressed with the punch 12
and the pad 14 with a pressure given by the pad 14. This allows formation of the
10 concave curved portion 10 in the central section of the work W (see FIG. 3B). At
this time, the height of the concave curved portion 10 in the work W is
approximately the same as the height of the other section of the work W.
Furthermore, the press surface 13b of the upper die 13 and the region facing the press
surface 13h of the upper die 13 in the press surface 12a of the punch 12 are
15 substantially spaced apart from the work W.
[0038]
Thereafter, the upper die 13 is continuously moved downward while the
work W is held between the punch 12 and the pad 14 for a drawing process.
Accordingly, a cylindrical surface-like portion is formed in the work W (see FIG.
20 3C). In association with this, the work W between the lower die 11 and the upper
die 13 is drawn into the inside, that is, into a space between the outer circumferential
section of the press surface 12a and the press surface 13h. Since the drawing
process is continued while the work W is held between the punch 12 and the pad 14,
the material hardly flows from the space between the punch 12 and the pad 14 into
25 the outer circumferential direction. As a result, the thickness of the work W within
the space between the punch 12 and the pad 14 hardly decreases. In addition, since
the work W is adequately pressed with the lower die 11 and the upper die 13, a
wrinkle is unlikely to be generated in the work W even when the work W is pulled
inward.
30 [0039]
The upper die 13 is hither continuously moved downward so that the work
W is pressed with the press surfacc 13b and the outer circumferential section of the
press surface 12a or the punch 12 (see FIG. 3D). This causes the portion between
the pressing surface 1 la of the lower die 11 and the pressing surface 13a of the upper
die 13 in the work W becomcs the flat plate portion 6. In addition, the portion
5 between the press surface 12a of the punch 12, and the press surface 14a of the pad
14 and the press surface 13b of the upper die 13 becomes the cylindrical drawn
poition 7. In this manner, the cylindrical drawn molded body 5 (see FIG. 2) is
obtained.
[0040]
10 In the cross section illustrated in FIG. 3D, about a right half in the
cylindrical drawn portion 7 of the work W (the cylindrical drawn molded body 5) is a
thickening target region T which is planned to be finally thickened the most. The
thickening target region T is set so as to contain at least part of the concave curved
portion 10.
15 [0041]
Since three thickened portions are formed in this embodiment as described
above, three thickening target regions Tare set. The three thickening target regions
T are set in such a manner as to appear at intervals of approximately 120" in the
circumferential direction with respect to the center (a specific center) of the hole-like
20 curved poition 8 (see FIG 2). The center of the hole-like curved portion 8, which
serves as the center of the plurality of thickening target regions T, may be positioned
at the center of the top portion 7b (on the central axis of the cylindrical drawn portion
7), or may be positioned off the center of the top portion 7b.
[0042]
25 The cross-sectional views of FIG. 3A to FIG. 3D and the below-described
drawings (FIG. 4A to FIG. 4D, FIG. 5A to FIG. 5D, FIG. 6A to FIG. 6D, FIG. 8A to
FIG. 8D, and FIG. 9A to FIG. 9D) each indicate a cross section (hereinafter, referred
to as a "central cross section") that extends through the center of the hole-like curved
portion 8 and is vertical to the flat plate portion 6. In these cross-sectional views,
30 only one of the three thickening target regions T appears.
[0043]
In the step illustrated in FIG. 3C and FIG. 3D, the actual length of each of
the thickening target rcgions T is longer than the actual length of the thickened
portion in the plate-likc molded body as a finished article, in the central cross
section.
5 [0044]
In the step illustrated in FIG. 3C and FIG. 3D, the work W is pressed with
the punch 12 and the pad 14, and the upper die 13 is continuously moved downward
while the work W is held between the punch 12 and the pad 14. In this mannel; a
cylindrical surface-like portion is formed in the work W by a drawing process. For
10 this reason, the state in which the concave curved portion 10 is pressed with the
punch 12 and the pad 14 is maintained during the drawing process. Therefore, the
thickness of the work W in the concave cwved portion 10 does not decrease in the
molding process. Thus, the thickness of the work W can be ensured at a maximum
before a subsequent thickening step is performed, and the thickening can be reliably
15 performed.
[0045]
Next, the cylindrical drawn portion 7 is deformed in such a manner as to be
gathered toward the central axis (cylindrical axis) side, and the portion around the
concave curved portion 10 of the work W is thickened. FIG. 4A to FIG. 4D are each
20 a cross-sectional view for explaining this step.
[0046]
In this step, there are used a lower die (blank holder) 16 and a punch 17 as
well as first and second upper dies 18 and 19 that are paired with and disposcd above
these mcmbers 16 and 17.
25 [0047]
A columnar hole penetrating in the vertical direction is formed in the lower
die 16. The punch 17 is guided in this hole and movable along the axial direction of
this hole. The upper surfaces of the lower die 16 and the punch 17 constitute a
pressing surface 16a and a press surface 17a, respectively.
30 [0048]
A columnar hole penetrating in the vertical direction and having the
substantially same lateral cross-sectional shape and size as those of the hole of the
lower die 16 is formed in the first upper die 18. The second upper die 19 is guided
in this hole aid movable along the axial direction of this hole. The lower surface of
the first upper die 18 constitutes a pressing surface 18a, and faces the pressing
5 surface 16a of the lower die 16. The lower surface of the second upper die 19
constitutes a press surface 19a, and faces the press surface 17a of the punch 17.
[0049]
The pressing surfaces 16a and 18a are flat. The central section of the press
surfaces 17a and 19a has a dome-like shape having a diameter smaller than that of
10 the cylindrical drawn portion 7. The outer circumferential sections of the press
surfaces 17a and 19a are a flat surface. In the central cross section, the actual
length of the press surfaces 17a and 19a is shorter than the actual length of the
portion corresponding to the press surfaces 17a and 19a in the work W as the
cylindrical drawn molded body 5. The actual length of the portion facing the
15 concave curved portion 10 of the cylindrical drawn molded body 5 in the press
surfaces 17a and 19a is particularly shorter than the actual length of the concave
curved portion 10.
[0050]
With reference to FIG. 4A, the height of the pressing surface 16a of the
20 lower die 16 and the height of the edge of the press surface 17a of the punch 17 are
first aligned to be approximately the same. Then, the work W as the cylindrical
drawn inolded body 5 is placed on a predetermined position of the pressing surface
16a and the press surface 17a. Thereafter, a wrinkle suppressing force is allowed to
act while the work W is held between the lower die 16 and the upper die 18.
25 [0051]
Subsequently, the second upper die 19 is moved downward to be pressed
against the work W. Since the diameter of the dome-like portion of the press
surfaces 17a and 19a is smaller than the diameter ofthe cylindrical drawn portion 7,
the work W is drawn in such a manner as to be gathered toward the central axis side
30 (see FIG. 4B).
[0052]
Thc second upper die 19 is further movcd downward. Accordingly, the
work W is gradually drawn toward the central axis side, and the second upper die 19
is pressed against the concave curved portion 10 of the work W (see FIG. 4C).
Then, the work W is pressed with the punch 17 and the second uppcr die 19 (see FIG.
5 4D). Since the actual length of the press surfaces 17a and 19a is shorter than the
actual length of the corresponding portion of the work W in the central cross section,
the work W, especially, the portion around the concave curved poi-tion 10, comes to
have a decreased actual length and an increased thickness.
[0053]
10 According to this step, the vicinity of three tops of the ring groove-like
curved portion 9 having a triangular shape (see FIG. 2) is thickened the most. The
direction of the most thickened portion of the work W with respect to the center of
the hole-like curved portion 8 coincides with the direction of the thickening target
region T, and the most thickened portion is contained in the thickening target region
15 T.
[0054]
In the step illustrated in FIG. 4B to FIG. 4D, the work W is pressed by the
lower die 16 and the first upper die 18 with a force that allows the work W between
the lower die 16 and the first upper die 18 to be adequately drawn into the space
20 between the press surface 17a and the press surface 19a.
[0055]
Next, the major portion of the thickening target region T in the work W is
thickened by pressing. FIG. SA to FIG. 5D are each a cross-sectional view for
explaining this step.
25 [0056]
In this step, there are used a lower die 21 and first and second upper dies 23
and 24 disposed above the lower die 21.
[0057]
A columnar hole penetrating in the vertical direction is formed in the first
30 upper die 23. The second upper die 24 is guided in this hole and movable along the
axial direction of this hole.
[005S]
A truncated cone-like protrusion 21P is fornlcd on the top of the lower die
21. The upper surface of the lower die 21 constitutes a press surface 21a. On the
press surface 21a, there is, around the protrusion 21P, a downward slope region in a
5 direction away from the protrusion 21P. Around this downward slope region, there
is a flat region arranged on the substantially same plane
[0059]
The lower surface of the second upper die 24 constitutes a press surface 24a,
and faces the surface of the protrusion 21P and the downward slope region in the
10 press surface 21a. The lower surface of the first upper die 23 constitutes a holding
surface 23a which is flat, and faces the flat region in the press surface 21a.
[0060]
Part of the downward slope region in the press smface 21a and the
corresponding region in the press surface 24a correspond to the thickening target
15 region T of a work W. As illustrated in FIG. 5A, while the thickening target region
T of the work W is curved upward to a large extent in a convex shape, the
corresponding regions in the press surfaces 21a and 24a are approximately flat.
Therefore, in the central cross section, the actual length of the thickening target
region T is longer than the actual length of the corresponding region in each of the
20 press surfaces 21a and 24a.
[0061]
When the thickening target region T is thickened, the flat portion in the
outer circumferential section of the work W is first held between the lower die 21
and the first upper die 23. At this time, the work W is pressed in a sufficiently
25 strong manner with the lower die 21 and the first upper die 23, so that even
application of a force in an in-plane direction to thc work W by pressing does not
cause the work W to move in such a direction. Then, the second upper die 24 is
moved downward to be pushed against the work W for pressing the work W with the
lowcr die 21 and the second upper die 24.
30 [0062]
In the central cross section, the actual length of thc region corresponding to
the thickening target region T in the press surfaces 21a and 24a is shorter than the
actual length of the thickening target region T. Therefore, this pressing causes the
work W to be deformed such that thc actual length of the thickening target region T
decreases (see FIG. 5B to FIG. 5D). Accordingly, the thickening target region T is
5 thickened and becomes flat. Since the thickening target region T contains a poi-tion
that has been thickened by pressing the concave curved portion 10 (see FIG. 4A to
FIG. 4D), the thickening target region T is significantly thickened compared to the
initial thickness of the work W.
100631
10 On the other hand, in the region other than the thickening target region Tin
the work W, thickening is not caused to a degree similar to that in the thickening
target region T.
[0064]
Thereafter, a step of adjusting the shape of the work W, the thickness of the
15 thickening target region T, and the like is further performed. FIG. 6A to FIG. 6D are
each a cross-sectional view for explaining this step. Ln this step, molding is
performed after the molded body obtained in the previous step (FIG. 5A to FIG. 5D)
is inverted using a conveyer or the like.
[0065]
20 In this step, there are used a lower die 26 and first and second upper dies 28
and 29 disposed above the lower die 26.
100661
A columnar hole penetrating in the vertical direction is formed in the first
upper die 28. The second upper die 29 is guided in this hole and movable along the
25 axial direction of this hole. The upper surface of the lower die 26 constitutes a
press surface 26a. The lower surfaces of the first and second upper dies 28 and 29
constitute press surfaces 28a and 29a, respectively.
[0067]
The shape of the press surface 26a is approxin~ately the same as the shape
30 obtained by aligning the positions of the holding surface 23a and the press surface
24a illustrated in FIG. 5A and vertically inversing the aligned surfaces. Howevel;
the actual length in the cross section is set to be slightly sl~oi-tetrh an that in FIG. 5A.
The shape of the press surfaces 28a and 29a is approximately the same as the shape
obtained by vertically inversing the press surface 21a illustrated in FIG. 5A.
However, while the protrusion 21P of the lower die 21 (sce FIG. 5A) has a truncated
5 cone shape as described above, a protrusion 28P corresponding to the protrusion 21P
in the first upper die 28 has a cylindrical shape. In addition, the region containing a
portion corresponding to the thickening target region T in the press surfaces 26a, 28a,
and 29a partly has a different shape from that of the press surfaces 24a and 21a as
described below.
10 [0068]
The press surface 29a and a region facing the press surface 29a in the press
surface 26a correspond to the thickening target region T of the work W. In the press
surface 21a illustrated in FIG. 5A, the region corresponding to the thickening target
region T slopes with respect to the flat portion in the outer circumference. On the
15 other hand, in the press surface 26a illustrated in FIG. 6A, the region corresponding
to the thickening target region T hardly slopes with respect to the flat portion in the
outer circumference, and is arranged on the substantially same plane. This
difference causes the thickening target region T of the work W illustrated in FIG. 6A
to FIG. 6D to extend in such a manner as to slope with respect to the corresponding
20 region of the press surfaces 26a and 29a. In addition, the actual length of the work
W in this region is longer than the actual length of the press surfaces 26a and 29a in
the central cross section.
[0069]
For adjusting the shape of the work W and the thickness of the thickening
25 target region T, the work W is first vertically inverted with respect to the state
illustrated in FIG. 5D, and placed on the lower die 26 such that the shape of the work
W follows the shape of the lower die 26. Then, the work W is pressed with the
lower die 26 and the first upper die 28. The portion folmed into a truncated cone
!
shape by the prot~usion 21P (see FIG. 5A) in the work W is remolded into a
30 cylindrical shape by the protrusion 28P (see FIG. 6B and FIG. 6C).
[0070]
Subsequently, while the pressing of the work W with the lower die 26 and
the first upper die 28 is maintained, the thickening target region T of the work W is
pressed with the lower die 26 and the second upper die 29. In the central cross
section, the actual length of the region corresponding to the thickening target region
5 T in the press surface 26a and the actual length of the press surface 29a are shorter
than the actual length of the thickening target region T. For this reason, this
pressing causes the actual length of the thickening target region T to decrease. As a
result, the thickening target region T is thickened to become a thickened portion A.
At the same time, the thickened poltion A and the flat portion (the flat plate portion 6
10 of the cylindrical drawn molded body 5) in the outer circumferential section of the
work W become in a substantially flat state as a whole (see FIG. 6D).
[0071]
Two other thickening target regions T which are not illustrated in FIG. 3A to
FIG. 6D are also thickened to become thickened portions A.
15 [0072]
Consequently, there is obtained a plate-like molded body 40 including a
plurality of thickened portions A in a region spaced apart from the edge in a
substantially flat plate-like portion.
[0073]
20 In the above-described embodiment, the major step for decreasing the actual
length of the thickening target region T in the central cross section is the step
illustrated in FIG. 5A to FIG. 5D. However, the actual length is decreased and thc
thickening target region T is thickened also in the step illustrated in FIG. 4A to FIG.
4D and the step illustrated in FIG. 6A to FIG. 6D. Furthermore, the step for finally
25 achieving a flat state as a whole between the thickening target region T and the flat
plate portion 6 (the flat portion in the outer circumferential section of the work W) is
the step illustrated in FIG. 6A to FIG. 6D. However, the thickening target region T
and the flat plate portion 6 are allowed to come into a substantially flat state as a
whole also in the step illustrated in FIG. 4A to FIG. 4D and the step illustrated in FIG.
30 5A to FIG. 5D.
[0074]

In this embodiment, a plate-like member including three thickened poi-tions
formed around the center is manufactured.
[0075]
5 The cylindrical drawn molded body 5 used in the first embodiment included
the hole-like curved portion 8 and the ring groove-like curved portion 9. However,
a cylindrical drawn molded body including only one of the hole-like curved portion 8
and the ring groove-like curved portion 9 may be used.
[0076]
10 FIG. 7 is a perspective view of a cylindrical drawn molded body. In FIG. 7,
a portion corresponding to the component illustrated in FIG. 2 is assigned with the
same reference numeral as that in FIG. 2, and the description thereof will be omitted.
In the top portion 7b of this cylindrical drawn molded body 5A, only the hole-like
curved portion 8 is formed as a concave curved portion 10A, and the ring groove-like
15 curved portion 9 (see FIG. 2) is not formed.
[0077]
Hereinafter, a method of forming such a cylindrical drawn molded body 5A
and using this for manufacturing a plate-like molded body will be described.
[0078]
20 FIG. 8A to FIG. 8D are each a cross-sectional view for explaining the
drawing step. In this step, a lower die (blank holder) 3 1 and a punch 32 as well as
an upper die 33 and a pad 34 that are paired with and disposed above the lower die
31 and the punch 32 are used for press molding to obtain the cylindrical drawn
molded body 5A as an intermediate molded body.
25 [0079]
The lower die 31, the punch 32, the upper die 33, and the pad 34 have the
approxilnately same configurations as the lower die 11, the punch 12, the upper die
13, and the pad 14 illustrated in FIG. 3A to FIG. 3D, respectively. However, a press
surface 34a of the pad 34 and a region facing the press surface 34a in a press surface
30 32a of the punch 32 have a shape corresponding to the concave curved portion 10A
of the cyliildrical drawn molded body 5A (see FIG. 7).
[0080]
With reference to FIG. 8A, the upper end of the press surface 32a is first
positioned lower than a pressing surface 3 la of the lower die 3 1, and a work W is
placed on the pressing surface 31a. Then, the work W is held between the lower die
5 3 1 and the upper die 33.
[008 11
.Subsequently, the upper die 33 is moved downward, so that the work W is
pressed with the punch 32 and the pad 44 with a pressure given by the pad 34
attached to the upper die 33. This allows formation of the concave curved portion
10 10A in the central section of the work W (see FIG. 8B). At this time, the height of
the concave curved portion 10A in the work W is approximately the same as the
height of the other section of the work W. Furthermore, the press surface 33b of the
upper die 33 and the region facing the press surface 33b of the upper die 33 in the
press surface 32a of the punch 32 are substantially spaced apart from the work W.
15 [0082]
Thereafter, the upper die 33 is continuously moved downward while the
work W is held between the punch 32 and the pad 34 for a drawing process.
Accordingly, a cylindrical surface-like portion is formed in the work W (see FIG.
8C). In association with this, the work W between the lower die 3 1 and the upper
20 die 33 is drawn into the inside, that is, into a space between the outer circumferential
section of the press surface 32a and the press surface 33b.
[0083]
The upper die 33 is further continuously moved downward so that the work
W is pressed with the press surface 33b and the outer circumferential section of the
25 press surface 32a of the punch 32 (see FIG. 8D). This causes the portion between
the pressing surface 31a of the lower die 3 1 and the pressing surface 33a of the upper
die 33 in the work W becomes the flat plate poition 6. In addition, the portion
between the press surface 32a of the punch 32, and the press surface 34a of the pad
34 and the press surface 33b of the upper die 33 becomes the cylindrical drawn
30 portion 7. In this manner, the cylindrical drawn molded body 5A (see FIG. 7) is
[0084]
In the cross section illustrated in FIG. 80, about a right half in the
cylindrical drawn portion 7 of the work W (the cylindrieal drawn molded body 5) is a
thickening target region T which is plalmed to be finally thickened the most. Since
5 three thickencd portions are formed in this embodiment as described above, three
thickening target regions T are set. The three thickening target regions T are set in
such a manner as to appear at intervals of approximately 120" in the circumferential
direction with respect to the center (a specific center) of the hole-like curved portion
8 (see FIG. 7).
10 [008S]
In the step illustrated in FIG. 8C and FIG. 8D, the actual length of each of
the thickening target regions T is longer than the actual length of the thickened
portion in the plate-like molded body as a finished article, in the central cross
section.
15 [0086]
Next, the cylindrieal drawn portion 7 is deformed in such a manner as to be
gathered toward the central axis side, and the portion around the concave curved
portion 10A of the work W is thickened. FIG. 9A to FIG. 9D are each a crosssectional
view for explaining this step,
20 [0087]
In this step, there are used a lower die 36 and a punch 37 as well as first and
second upper dies 38 and 39 that are paired with and disposed above these members
36 and 37. The lower die (blank holder) 36, the punch 37, the first upper die 38,
and the second upper die 39 have the approximately same configurations as the lower
25 die 16, the punch 17, the first upper die 18, and the upper die 19 illustrated in FIG.
4A to FIG. 4D, respectively.
[0088]
The central section of a press surface 37a of the punch 37 and the central
section of a press surface 39a of the second upper die 39 have a dome-like shape
30 having a diameter smaller than that of the cylindrical drawn portion 7. In the
central cross section, the actual leilgth of the press s~~rfac3e7s a and 39a is shorter
than the actual length of a portion corresponding to the press surfaces 3721 and 39a in
the work W as the cylindrical drawn molded body 5A. Thc actual length of the
portion corresponding to the concave curved portion 10A of the cylindrical drawn
molded body 5A in the press surfaces 37a and 39a is particularly shorter than the
5 actual length of the concave curved portion 1OA.
[0089]
With reference to FIG. 9A, the height of the pressing surface 36a of the
lower die 36 and the height of the edge of the press surface 37a of the punch 37 are
first aligned to be approximately the same, and a work W as the cylindrical drawn
10 molded body 5A is placed at a predetermined position on the pressing surface 36a
and the press surface 37a. Then, the work W is held between the lower die 36 and
the first upper die 38.
[0090]
Subsequently, the second upper die 39 is moved downward to be pressed
15 against the work W. Since the diameter of the dome-like portion of the press
surfaces 37a and 39a is smaller than the diameter of the cylindrical drawn portion 7,
the work W is deformed in such a manner as to be gathered toward the central axis
side (see FIG. 9B).
[0091]
20 Furihertnore, the second upper die 39 is moved downward to press the
second upper die 39 against the concave curved portion 10.4 of the work W (see FIG.
9C), so that the work W is pressed with the punch 37 and the second upper die 39
(see FIG. 9D). Since the actual length of the press surfaces 37a and 39a is shorter
than the actual length of the corresponding portion of the work W in the central cross
25 section, the work W, especially, the portion around the concave curved portion 10A,
comes to have a decreased actual length and an increased thickness.
[0092]
However, since the concave cuived poi-tion 10A does not contain the ring
groove-like curved portion 9 (see FIG. 2), the thickening rate of the thickening target
30 region T by the above-described step is smaller than the thickening rate of the
thickening target region T in the step illustrated in FIG. 4B to FIG. 4D.
[0093]
Thereaftel; steps similar to the step illustrated in FIG. 5A to FIG. 5D and the
step illustrated i11 FIG. 6A to FIG. 6D according to the first embodiment are
performed. Consequently, thcre is obtained a plate-like molded body including a
plurality of thickened portions in a region spaced apart from the edge in a
substantially flat plate-like portion.
[0094]
However, since the thickening by pressing the ring groove-like curved
portion 9 is not obtained, the thickening rate of the thickened portion obtained in the
manufacturing method according to the second embodiment is smaller than the
thickening rate of the thickened portion obtained by the manufacturing method
according to the first embodiment. However, even in the second embodiment, the
thickened portion has a thickening rate of 20% or more with respect to an initial plate
thickness as the plate thickness of the cylindrical drawn molded body, and has a
length of five times or more the initial plate thickness in the central cross section.
[0095]
In the above description, when press is performed with a lower mold and an
upper mold, the upper mold may be moved downward instead of moving the lower
mold upward, and the lower mold may be moved upward instead of moving the
upper mold downward.
[0096]
As described above, in the thickening step, the actual length of the
thickening target region T is decreased while wrinkles generated by out-of-plane
deformation during molding are suppressed. Accordingly, the thickening target
region T is thickened to become a thickened portion. Also, in the thickening step,
the thickening target region T and the flat plate portion (the outer circumferential
section of the cylindrical drawn molded body) come into a flat state as a whole. For
this reason, according to this method, there can be manufactured a plate-like molded
body having a thickened portion in a region spaced apart from the edge in a
substantially flat plate-like portion.
100971
In addition, two or more thickening target regions T are set along the
circumferential direction with respect to a specific center. Therefore, according to
this mcthod, there can be manufactured a plate-like molded body on which a
plurality of thickened portions appear along the circumferential direction with
5 respect to the center.
[0098]
Furthermore, the actual length of the concave curved portion 10 is longer
than that of the cross section that does not include a concave curvature. Since the
thickening target region T is folmed in a region containing at least part of the
10 concave curved portion 10, the concave curved portion 10 is thickened particularly
thickly in the thickening target region T by pressing in the thickening step.
100991
FIG. 10 is a characteristics diagram illustrating plate thicknesses of the
cylindrical drawn molded bodies 5 and 5A. When the cylindrical drawn molded
15 bodies 5 and 5A are manufactured according to the above-described embodiments,
the plate thickness in the thickened portion A is increased compared to the plate
thickness before processing (standard plate thickness). On the other hand, in the
region suppressed by the pad 14 during processing, the material hardly flows out
from the space between the punch 12 and the pad 14 toward the outer circumference,
20 but the region is slightly thinned in some cases. In addition, an unthickened region
around the region suppressed by the pad 14 is also slightly thinned in some cases.
These regions having been thinned are referred to as a thinned portion.
Measurement of the plate thicknesses of the cylindrical drawn molded bodies 5 and
5A indicated that a standard plate thickness t [mm], a plate thickness ti [mm] of a
25 thickened portion, and a plate thickness td [m] of a thinned portion that is thinner
than the standard plate thickness have a relationship,. illustrated in FIG. 10 and the
table below. Here, the standard plate thickness is the plate thickness of a region
excluding the thickened portion and the thinned portion in each of the cylindrical
drawn molded bodies 5 and 5A.
30 [oleo]
[Table 11
I Standard plate / Maximum I Minimum
thickness / thinning rate I thickening rate
2.6 / 90% 1 125%
[0101]
Therefore, according to the manufacturing methods of the above-described
embodiments, there can be molded a plate-like molded body in which when t [rnnl] is
a standard plate thickness, a plate thickness ti [rnm] of a thickened portion and a
5 plate thickness td [mm] of a thinned portion satisfy relational formulae below:
when 2.0 < t < 3.0, td 2 0.9t, ti t 1.251,
when 3.0 < t < 4.0, td 2 0.9t, ti > 1.35t, and
when4.0 < t < 5.0, td 2 0.9t, ti 2 1.4%.
[O 1021
10 Thus, according to the manufacturing methods of the above-described
embodiments, the thickened portion having been thickened with respect to the
standard plate thickness and the thinned portion having been slightly thinned with
respect to the standard plate thickness are formed depending on the standard plate
thickness. The maximum thinning rate in the thinned portion is approximately
15 90%, which demonstrates that the outflow of the material is suppressed to a
minimum. Therefore, according to the above-described embodiments, molding in a
state in which a material is held between the punch 12 and the pad 14 enables
molding of the cylindrical drawn molded bodies 5 and 5A that suppress the outflow
of the material in the thinned portion and that are thickened by 25% or more in the
20 thickened portion.
[0 1031
It should be understood by those skilled in the at that various modifications,
combinations, sub-combinations and alterations may occur depending on design
requirements and other factors insofar as they are within the scope of the appended
25 claims or the equivalents thereof.
Reference Signs List
[0 1041
5,5A cylindrical drawn molded body
6 flat plate portion
5 7 cylindrical drawn portion
7b top portion
8 hole-like curved porlion
9 ring groove-like curved poi-tion
10,lOA concave curved porlion
10 ll,31 lower die
13,33 upper die
12,32 punch
14,34 pad
40 plate-like molded body
15 A thickened portion
T thickening target region
W work (body to be processed)
CLAIMS
Claiin 1
A method of manufacturing a plate-like molded body having a plurality of
thickened portions, comprising at least
5 a drawing step of obtaining by a drawing process a cylindrical drawn
molded body including a flat plate portion and a cylindrical drawn portion that swells
in such a manner as to project from the flat plate portion and has a circular top
poition,
wherein the drawing step includes
a first step of pressing a region spaced apart fiom an edge in a
plate-like member having a flat plate shape, with a first mold and a second mold, to
form a concave curved portion in the plate-like member, and
a second step of holding an outer circumferential section of the
plate-like member between a third mold and a fourth hold while a region containing
15 the concave curved portion in the plate-like member is held between the first mold
and the second mold, and moving the first mold and the second mold relative to the
third mold and the fourth mold to cause the region containing the concave curved
portion to project with respect to the outer circumferential section and to obtain the
cylindrical drawn molded body.
20
Claim 2
The method of manufacturing the plate-like molded body according to claim
1,
wherein the first step includes fo~rning the concave curved portion in a
25 region corresponding to the top portion, and
wherein the second step includes setting a plurality of thickening target
regions containing at least a part of the concave curved portion along a
circumferential direction with respect to a specific center in a region corresponding
to the cylindrical drawn portion, and performing a drawing process such that in a
30 cross section that is vertical to the flat plate portion and contains the specific centel;
an actual length of the thickening target region becomes longcr than an actual length
of the thickened portion in the plate-like molded body.
Claim 3
The method of manufacturing the plate-like molded body according to claim
6 2, further comprising, after the drawing step, a thickening step of pressing the
cylindrical drawn molded body such that an actual length of each of the thickening
target regions in the cross section decreases, and the thickening target region and the
flat plate portion finally become flat as a whole.
10 Claim 4
The method of manufacturing the plate-like molded body according to any
of claims 1 to 3, wherein the concave curved portion includes a hole-like curved
portion that is curved in a hole shape.
15 Claim 5
The method of manufacturing the plate-like molded body according to claim
4, wherein the concave curved portion further includes a ring groove-like curved
portion that is curved in a groove shape and formed around the hole-like curved
portion in such a manner as to have a polygonal shape as a whole when seen
20 vertically to the flat plate portion.
Claim 6
The method of manufacturing the plate-like molded body according to any
of claims 1 to 3, wherein the concave curved portion includes a ring groove-like
25 curved portion that is curved in a groove shape and formed in such a manner as to
have a polygonal shape as a whole when seen vertically to the flat plate portion.
Claim 7
The method of manufacturing the plate-like molded body according to any
30 of claims 1 to 6, wherein the thickened portion has a plate thickness with a
thickening rate of 20% or more with respect to an initial plate thickness as a plate
thiclu~esso f the cylindrical drawn ~lloldedb ody, and has a length of five tiines o,rI ', ./ ','jj,.,:> .
ulore the initial plate thiclu~cssin the cross section.
,
3 Claisll 8
5 A plate-lilce lllolded body having a plurality of thicliencd portions,
conlplising:
a flat plate portion; and
a cylindrical drawn portion that swells in such a nlalulcr as to project _Tom
the flat plate portioil and has a circular top portion,.
10 1~11ereir1w l~ent [snm] is a standard plate thiclu~essa, plate tluclcness ti [IIUII]
of the thicltened portion and a plate thickness td [IIUII] of a thinned portiotl having a
smaller tliclu~essth an the standard plate thiclu~esss atisfy relational formulas below:
wl1e1l2.00.9t,tit1.25t,
whe1i3.01.35t,a11d
15 when4.0 1.45t: