[Technical Field of the Invention]
[0001]
The present invention relates to a cutting device and a cutting method.
Priority is claimed on Japanese Patent Application No. 2015-020331, filed on
February 4, 2015, the content of which is incorporated herein by reference.
[Related Art]
[0002]
For example, a thin-plate processed part 8 (a press-formed product) shown in
FIG. 10 is used for automobiles, railway vehicles, building materials, ships, home
appliances, and the like. The thin-plate processed part 8 is manufactured through, for
example, a cutting step of cutting (shearing) an end portion 3 in a longitudinal
direction of a plate material 1 shown in FIGS. 7 A and 7B along a curved cutting line 2,
and a pressing step of press fom1ing the plate material I after the cutting step (that is, a
processed material portion 4 of the plate material I). FIG. 7 A is a plan view of the
plate material I, and FIG. 7B is an enlarged view of a p01tion indicated by symbol X of
FIG.7A.
[0003]
FIG. 8 is a sectional schematic diagram showing a cutting device I 0 of the
related art, which is used when cutting the plate material I. As shown in FIG. 8,
when cutting the end po1tion 3 of the plate material I, an upper blade 12 having a
predetermined clearance CL/t (%) with respect to a lower blade II is moved down
while the plate material! is clamped by the lower blade 11 and a plate holder 13. In
this way, the end p01tion 3 of the plate material I is cut off, and thus a processed
- I -
i
material 6 is obtained from the plate material 1. As shown in FIG. 8, CL represents
the distance between the upper blade 12 and the lower blade 11, and t represents the
plate thickness of the plate material!. That is, the "clearance CL!t (%)"represents
the ratio of the distance CL to the plate thickness t.
[0004]
FIG. 9 is a sectional schematic diagram showing a press forming device 20
which is used when press-forming the processed material6. As shown in FIG. 9, the
thin-plate processed part 8 shown in FIG. I 0 can be obtained by performing stretch
flanging on the processed material 6 by using a punch 21, a die 22, and a pad 23.
[0005]
Here, in the cutting step shown in FIG. 8, when cutting off the end pot1ion 3
from the plate material l, there is a case where burrs are generated in the processed
material portion 4 of the plate material 1. The burrs are hardened by strong
processing, and therefore, the workability (fonnability) of the processed material6 is
lowered. Then, if the workability of the processed material 6 is lowered, a decrease
in the yield and an increase in the manufacturing cost of the thin-plate processed part 8
occur. The burrs are remarkably generated as the clearance CL!t (%)is larger (for
example, more than 10% ), and therefore, it is impot1ant to control the clearance CL!t
(%)to a predetermined value (less than or equal to 10%, for example) in order to
increase the mass productivity of the thin-plate processed pat1 8.
[0006]
However, from the viewpoint of manufacturing accuracy or the like of a die
and punch, it is not easy to control the clearance CL!t between the upper blade 12 and
the lower blade II to a predetermined value (less than or equal to 10%, for example)
when cutting the plate material I along the curved cutting line 2. Further, even in a
- 2 -
case where the plate material! is cut in a linear fashion, the clearance CL/t varies due
to elastic deformation or the like of a die and punch, which occurs at the time of the
cutting of the plate material 1. Therefore, it is not easy to control the clearance CL/t
to a predetermined value and to suppress burr occurrence in a mass production process.
[0007]
Here, Patent Document 1 discloses a punching die in which burrs generated
during punching are crushed by rollers provided up and down. Further, Patent
Document 2 discloses a method of preventing the generation of burrs in the cross
section of a hole-fanned portion by performing punch pressing at the same position
and in the same shape from above and below a plate material.
[0008]
However, in Patent Document 1, the burrs generated by the punching are
crushed, and therefore, the crushed portion is hardened, so that the workability is
further lowered. Further, in Patent Document 2, since punch pressing at the same
position and in the same shape is pe1fmmed from above and below the plate material,
two press machines are required, and thus a cost such as the cost of equipment
increases.
[Prior A1t Document]
[Patent Documents]
[0009]
[Patent Document 1] Japanese Unexamined Patent Application, First
Publication No. H10-263721
[Patent Document 2] Japanese Unexamined Patent Application, First
Publication No. Hll-221628
[Disclosure of the Invention]
- 3 -
[Problems to be Solved by the Invention]
[001 0]
The inventors of the present invention have focused on falling-down of the
plate material 1 when cutting the plate material 1, as a factor of occurrence of the burrs
in the processed material 6.
FIG. 11 is a schematic diagram showing a state where the upper blade 12
shown in FIG. 8 is moved down and is a diagram showing a state during cutting. As
shown in FIG. 11, ifthe upper blade 12 is moved down in a state where the plate
material 1 is clamped by the lower blade 11 and the plate holder 13, the upper blade 12
comes into contact with the smface of the plate material 1, and thus the end portion 3
of the plate material 1 falls down.
[0011]
If such falling-down of the plate material 1 occurs, it is difficult for the lower
blade 11 to bite into the plate material 1, and thus cracking from a place which is in
contact with the lower blade 11 becomes difficult to occur. Fmiher, due to the fallingdown
of the plate material 1, tension acts on the plate material 1, and thus cracking
from the upper blade 12 becomes easy to occur. For this reason, if the upper blade 12
is further moved down from the state shown in FIG. 11, cracking occurs from a place
which is in contact with the upper blade 12, and thus a cut surface S is formed in the
moving direction of the upper blade 12, and as a result, burrs are generated. The
above-mentioned falling-down is governed by the elastic deformation of the plate
material!, and therefore, the falling-down angle of the plate material] becomes large
as the tensile strength of the plate material I increases. In other words, the larger the
tensile strength of the plate material 1 is, the larger the burrs generated in the processed
material 6 become.
- 4 -
[0012]
The present invention has been made in view of the above circumstances and
has an object to provide a cutting device and a cutting method, in which occurrence of
burrs when cutting off an end portion of a plate material can be easily suppressed at
low cost.
[Means for Solving the Problem]
[0013]
In order to solve the above problem, the present invention adopts the
following.
(1) According to an aspect of the present invention, there is provided a cutting
device for obtaining a processed material by cutting off an end p01tion of a plate
material by a first cutting blade and a second cutting blade which relatively approach
each other, the cutting device including: a first contact part and the first cutting blade
which clamp a processed material portion to be the processed material, of the plate
material, from front and back surfaces thereof; the second cutting blade and a second
contact part which clamp an end material portion to be the end portion, of the plate
material, from front and back surfaces thereof; and a drive part which causes the first
cutting blade and the second cutting blade to start relative approach each other while
maintaining a flat state where the processed material p01tion and the end material
p01tion are on the same plane, on at least one of the front surface and the back surface
of the plate material.
(2) In the aspect according to the above (I), a cutved portion is formed in each
of the first cutting blade and the second cutting blade in a case of being viewed in a
direction in which the first cutting blade and the second cutting blade approach each
other.
- 5 -
(3) In the aspect according to the above (2), the curvature of the curved
portion of the first cutting blade may be greater than or equal to -0.07 mm ·I and less
than or equal to 0.20 mm -I.
(4) In the aspect according to any one of the above (1) to (3), a clearance
between the first cutting blade and the second cutting blade may be more than 10% and
less than or equal to 30%.
(5) In the aspect according to any one ofthe above (1) to ( 4), a pressurizing
force of the second contact part with respect to the end material portion may be greater
than or equal to 0.05 kN.
(6) In the aspect according to any one of the above (1) to (5), the second
contact part may include a flat portion which comes into contact with the end material
portion of the plate material.
(7) In the aspect according to the above (6), a minimum width dimension of
the flat portion may be greater than or equal to a plate thickness of the plate material.
(8) In the aspect according to the above (6) or (7), a maximum width
dimension of the flat portion may be less than 0.5 times a minimum width dimension
of the end portion ofthe plate material.
(9) In the aspect according to the above ( 6) or (7), a maximum width
dimension of the flat portion may be less than or equal to 30 mm.
(1 0) In the aspect according to any one of the above (1) to (9), the cutting
device may futiher include: an end member removal part which applies an external
force to the end pmiion after cutting of the plate material and after release of clamping
of the end pmiion by the second cutting blade and the second contact part.
(11) According to another aspect of the present invention, there is provided a
cutting method for obtaining a processed material by cutting off an end portion of a
- 6 -
plate material by a first cutting blade and a second cutting blade which relatively
approach each other, the cutting method including: clamping a processed material
portion to be the processed material, of the plate material, from front and back surfaces
thereof; clamping an end material portion to be the end portion, of the plate material,
from front and back surfaces thereof; and causing the first cutting blade and the second
cutting blade to start relative approach each other while maintaining a flat state where
the processed material pmiion and the end material portion are on the same plane, on at
least one of the front surface and the back surface of the plate material.
(12) In the aspect according to the above (11), tension may not be applied to
either of the front surface or the back surface of the plate material at the time of start of
the approach.
(13) In the aspect according to the above (II) or (I2), a clearance between the
first cutting blade and the second cutting blade may be set to be more than I 0% and
less than or equal to 30%.
(I4) In the aspect according to any one of the above (11) to (13), a
pressurizing force when clamping the end material portion may be set to be greater
than or equal to 0.05 kN.
(15) In the aspect according to any one of the above (11) to (I4), the plate
material may be a steel plate having tensile strength greater than or equal to 440 MPa.
(16) In the aspect according to any one of the above (11) to (15), a plate
thickness of the plate material may be in a range of0.6 mm to 3.6 mm.
[Effects of the Invention]
[0014]
According to each of the above aspects of the present invention, the
occurrence of burrs when cutting off the end pmiion of the plate material can be easily
- 7 -
suppressed at low cost.
[Brief Description of the Drawings]
[0015]
FIG. IA is a perspective view showing a cutting device according to an
embodiment of the present invention.
FIG. IB .is a plan view showing the cutting device.
FIG. IC is a cross-sectional view taken along line A-A of the cutting device
shown in FIG. IA.
FIG. 2 is a cross-sectional view taken along lineA-A of the cutting device
shown in FIG. lA and is a diagram showing a state after cutting.
FIG. 3 is cross-sectional photographs of a processed material obtained by the
cutting device and a processed material obtained by a cutting device of the related art.
FIG. 4 is a graph showing a change in burr height according to the presence or
absence of a falling-down prevention member.
FIG. 5 is a graph showing a relationship between a set load of the fallingdown
prevention member and a limit H/limit_refcrence.
FIG. 6 is a graph showing a relationship between a width of the falling-down
prevention member and the limit H/limit_reference.
FIG. 7 A is a plan view showing a plate material.
FIG. 7B is an enlarged view of a portion indicated by symbol X of FIG. 7 A.
FIG. 8 is a sectional schematic diagram showing the cutting device of the
related art.
FIG. 9 is a sectional schematic diagram showing a press forming device and is
a diagram showing a state during forming.
FIG. I 0 is a perspective view showing an example of a thin-plate processed
- 8 -
part.
FIG. 11 is a diagram for explaining a mechanism of occurrence of burrs by the
cutting device of the related art.
[Embodiments of the Invention]
[0016]
Hereinafter, an embodiment of the present invention will be described in
detail with reference to the drawings. In this specification and the drawings,
constituent elements having substantially the same functional configuration are
denoted by the same reference numerals, and thus an overlapping description thereof is
omitted.
[0017]
FIGS. 1A to 1 C are diagrams showing a cutting device 100 according to an
embodiment of the present invention. FIG. 1A is a perspective view of the cutting
device 100, FIG. 1B is a plan view of the cutting device 100, and FIG. 1 C is a crosssectional
view taken along line A-A of the cutting device 100 shown in FIG. !A. The
cutting device 100 cuts off an end p01tion 3 in a longitudinal direction of a plate
material 1 (an end material portion of the plate material 1) along a curved cutting line 2
(performs outline trimming) by moving an upper blade 102 in a vertical direction Z (a
direction in which the upper blade 1 02 approaches a lower blade 101 ), as shown in
FIGS. 1A and 7 A. In FIG. lA, in order to make the drawing easier to be read, the
upper blade 102 and the plate material 1 are indicated by two-dot chain lines.
[0018]
A material of the plate material 1 is, for example, metal such as iron,
aluminum, stainless steel, copper, titanium, magnesium, or steel. The material of the
plate material! is not limited to only those listed above and may be a composite
- 9 -
material composed of metal and resin, a dissimilar metal, or the like.
Further, a plate thickness of the plate material! is preferably in a range of 0.6
mm to 3.6 mm, more preferably in a range of 0.6 mm to 2.3 mm, and further preferably
in a range of0.6 mm to 1.8 mm.
[0019]
As shown in FIGS. lA to 1 C, the cutting device 100 is provided with the
lower blade 101 (a first cutting blade), a plate holder 104 (a first contact part) disposed
so as to face the lower blade 10 1, a pair of upper blades 1 02 (second cutting blades)
disposed to be separated from both end surfaces 1 04a in a longitudinal direction of the
plate holder 104 by a predetermined distance, a pair of falling-down prevention
members 105 (second contact parts) disposed so as to face the pair of upper blades 102,
and a pair of scrap boxes ll 0.
[0020]
The lower blade 101 is fixed to a floor surface (not shown). The plate holder
104 is made to be movable in the vertical direction Z. Then, when cutting the plate
material 1, a processed material portion 4 of the plate material 1 is clamped by the
lower blade 101 and the plate holder 104 from two surfaces (the front and back
surfaces) in a through-thickness direction of the plate material 1.
[0021]
The upper blade 1 02 is disposed to be separated from the lower blade 1 01 by
a predetermined distance such that a clearance CL!t (a value obtained by dividing a
distance CL between the upper blade 102 and the lower blade 101 by a plate thickness
t of the plate material 1: refer to FIG. 8) is in a range of 5% to 30%, for example.
That is, the distance between an end surface 1 02a (a curved portion) of the upper blade
1 02 and an end surface 1 0 1 a (a curved portion) of the lower blade 1 01 is in a range of
- 10 -
5% to 30% of the plate thickness t of the plate materiall. Each of the pair of upper
blades 102 is installed at a drive unit 120 (a drive pmt) and made to be movable in the
vertical direction Z.
[0022]
Further, as shown in FIG. 1 C, each of the pair of upper blades 1 02 has a recess
pmtion 102b provided in a lower end pmtion thereof, a pressing bar 109 (an end
material removal part) provided inside of the recess portion 1 02b, and an elastic body
1 08 which biases the pressing bar I 09 so as to push out it from the recess portion 1 02b.
The elastic body 108 is, for example, a coil spring, a leaf spring, or the like. The
biasing force of the elastic body I 08 is set to a force to the extent that does not deform
the plate material I. The end portion 3 of the plate material I falls downward under
an external force from the pressing bar l 09 and the elastic body l 08 after cutting.
[0023]
The falling-down prevention member l 05 has a trapezoidal cross section, as
shown in FIG. IC, and has a top plate surface l05a (a flat portion) which comes into
contact with the lower surface of the end pmtion 3 of the plate material l, a side end
surface l 05c connected to the top plate surface I 05a and perpendicular to the top plate
surface I 05a, an inclined surface I 05b connected to the top plate surface 1 05a and
inclined with respect to the top plate smface I 05a, a bottom surface I 05d parallel to
the top plate surface I 05a, and an elastic body 107 provided on the bottom surface
I 05d. The elastic body I 07 biases the falling-down prevention member I 05 toward
the upper blade I 02. The elastic body l 07 is, for example, a coil spring, a leaf spring,
or the like. Instead of the elastic body 107, a gas cylinder or the like may be provided.
Fmther, the falling-down prevention member l 05 is disposed such that a
distance D between the side end surface I 05c thereof and the end surface I 0 I a of the
- 11 -
i
lower blade 101 is in a range ofO.Ol mm to 100 mm. The distanceD is more
preferably in a range ofO.Ol mm to 50 mm and further preferably in a range ofO.Ol
mm to 10 mm.
[0024]
When cutting the plate material!, the end portion 3 in the longitudinal
direction of the plate material! is clamped by the upper blade I 02 and the fallingdown
prevention member 105 from two surfaces (the front and back surfaces) in the
through-thickness direction of the plate material I. At this time, the elastic body I 07
is set so as to have a pressurizing force greater than or equal to 0.05 kN.
[0025]
The pair of scrap boxes II 0 is disposed below the falling-down prevention
members lOS, as shown in FIG lA. Then, the scrap boxes llO accommodate the end
portions 3 cut from the plate material!.
[0026]
Further, as shown in FIGS. !A and lB, each of the end surface lOla of the
lower blade I 01 and the end surface I 04a of the plate holder I 04 has a curved shape
along the cutting line 2 of the plate material! shown in FIG. 7A in a case of being
viewed in the vertical direction Z. Furthe1~ each of the end smface I 02a of the upper
blade 102 and the side end surface lOSe of the falling-down prevention member 105
also has a curved shape along the cutting line 2 of the plate material I in a case of
being viewed in the vertical direction Z. That is, the falling-down prevention member
105 has a shape along the end surface 102a of the upper blade 102.
[0027]
A width W of the top plate surface 105a of the falling-down prevention
member 105 (the length of the top plate surface 1 05a in a direction crossing the cutting
- 12 -
line 2 of the plate material!: refer to FIG. lC) varies in the longitudinal direction of
the top plate surface 1 05a, because the falling-down prevention member I 05 has a
curved shape. It is preferable that the maximum dimension of the width W of the top
plate surface 1 05a is smaller than 0.5 times the minimum dimension of a cutting width
w of the plate material 1 (that is, the width of the cut-off end portion 3 of the plate
material 1: refer to FIG. 7 A). In this way, the center of gravity of the cut end portion
3 of the plate material! is not located on the top plate surface 105a ofthe falling-down
prevention member 105, and therefore, the end pm1ion 3 of the plate material! can be
dropped downward. The maximum dimension of the width W of the top plate surface
1 05a is Jess than or equal to 30 mm, for example.
On the other hand, it is preferable that the minimum dimension of the width
W of the top plate surface 1 05a is greater than or equal to the plate thickness of the
plate material 1. In this case, it is possible to increase the thickness of the fallingdown
prevention member 105, and thus it is possible to improve the strength of the
falling-down prevention member 1 05.
[0028]
Next, a method of obtaining a processed material 7 by cutting off the end
pm1ion 3 of the plate material! by using the cutting device 100 will be described.
First, as shown in FIGS. lA and 1 C, the plate material 1 is disposed between the lower
blade 1 01 and the plate holder 104, and the processed material portion 4 of the plate
material! is clamped by the lower blade 101 and the plate holder 104. Thereafter,
the end portion 3 of the plate material 1 is clamped by the upper blade 1 02 and the
falling-down prevention member 105. At this time, the end pm1ion 3 of the plate
material 1 is pressurized due to the elastic body 107 provided at the falling-down
prevention member I 05.
- 13 -
[0029]
Subsequently, the upper blade 102 is moved down (the upper blade 102 is
brought close to the lower blade 101 ), and thus the end portion 3 of the plate material 1
is cut. At this time, since the falling-down prevention member 1 OS is pressing the
end p01tion 3 of the plate material 1, the falling-down (refer to FIG. 11) of the end
portion 3 of the plate material 1 can be prevented. For this reason, tension (tension in
the direction crossing the cutting line 2 of the plate material!) is prevented from acting
on the plate material 1, and the lower blade 101 easily bites into the plate material!.
As a result, cracking can occur from the upper blade 102 and cracking can also occur
from the lower blade 101. Therefore, buns can be prevented from being generated in
the processed material 7.
[0030]
Finally, as shown in FIG. 2, the upper blade 102 is moved up, and thus the
cutting of the plate material 1 is ended. At this time, the upper blade 102 moves up,
whereby the clamping of the end portion 3 of the plate material I after cutting is
released, and therefore, the end pmtion 3 falls under the external force by the pressing
bar 109 of the upper blade 102. For this reason, the end portion 3 of the plate
material 1 after cutting can be reliably dropped, and therefore, the efficiency of the
cutting work can be improved. Then, the scrap box 110 is provided below the fallingdown
prevention member I OS (refer to FIG. lA), and therefore, the end portion 3 is
guided by the inclined surface 1 OSb of the falling-down prevention member 1 OS and
accommodated in the scrap box I 1 0.
[0031]
Through the above steps, it is possible to obtain the processed material 7 from
the plate material 1 by using the cutting device I 00. Then, stretch flanging is
- 14 -
performed on the processed material 7 by using a press forming device 20 shown in
FIG. 9, whereby it is possible to manufacture a press-formed product having a stretch
flanged pati. At this time, occurrence of burrs is suppressed in the processed material
7, and therefore, it is possible to suppress occurrence of forming defects at the time of
the stretch flanging. As a result, it is possible to suppress a decrease in the yield and
an increase in the manufacturing cost of the press-formed product, and thus it is
possible to mass-produce the press-formed product with high yield.
[0032]
According to the cutting device 100 according to the embodiment described
above, the upper blade 102 starts to approach the lower blade 101 while the lower
surface of the end portion 3 of the plate material 1 is pressurized by the falling-down
prevention member 105. In other words, the upper blade 102 statis to approach the
lower blade 101 while maintaining a flat state where the processed material portion 4
and the end potiion 3 ofthe plate material 1 are on the same plane (without applying
tension to two surfaces in the through-thickness direction of the plate material!). For
this reason, it is possible to prevent the end portion 3 of the plate material 1 from
falling-down, and thus it is possible to suppress the occurrence of burrs in the
processed material 7. Therefore, the occurrence of burrs can be easily suppressed at a
low cost.
[0033]
As described above, in the cutting device 10 of the related art (refer to FIG.
11 ), in a case where the clearance CL/t is large (more than I 0%, for example), buns
are conspicuously generated due to the falling-down of the plate material. However,
in the cutting device 1 00 according to the embodiment, it is possible to prevent the
. plate material from falling-down, and therefore, the occurrence of burrs in the
- 15 -
processed material 7 can be suppressed even in a case where the clearance CL/t is large.
[0034]
Further, the higher the tensile strength of the plate material 1 is, the more
easily the falling-down occurs. Therefore, from the viewpoint of the effect of fallingdown
prevention, the plate material! is preferably a steel plate having tensile strength
greater than or equal to 440 MPa, more preferably a steel plate having tensile strength
greater than or equal to 590 MPa, and fmiher preferably a steel plate having tensile
strength greater than or equal to 980 MPa.
Fmiher, the thinner the plate thickness of the plate material! is, the more
easily the falling-down occurs. Therefore, the thinner the plate thickness of the plate
material I is, the greater the effect of falling-down prevention becomes.
[0035]
Further, in the plate material 1, in a case where the curvature of the cutting
line 2 of the plate material 1 is greater than or equal to -0.07 mm-1
, the falling-down at
the time of cutting occurs conspicuously. For this reason, in a case where the
cmvature of the cutting line 2 is greater than or equal to -0.07 mm -!,the effect of
falling-down prevention increases. Here, the negative curvature represents a concave
curve, and the positive curvature represents a convex curve.
On the other hand, in a case where the cmvature of the cutting line 2 of the
plate material 1 exceeds 0.20 mm -!,when the stretch flanging is performed on the
processed material 7 by using the press forming device 20 shown in FIG. 9, stress
concentration occurs in the processed material 7, whereby breakage sometimes occurs.
For this reason, li"om the viewpoint of suppressing breakage at the time of the stretch
flanging, it is preferable that the cmvature of the cutting line 2 of the plate material I is
less than or equal to 0.20 mm-1
•
- 16 -
Therefore, it is preferable that the curvature of the cutting line 2 of the plate
material 1 is greater than or equal to -0.07 mm -I and less than or equal to 0.20 mm-1
•
[0036]
In other words, since the plate material 1 is cut along the shapes of the lower
blade I 01 and the upper blade 102, it is preferable that the curvature of the end surface
I Ola of the lower blade 101 is greater than or equal to -0.07 mm -I and less than or
equal to 0.20 mm-1 and it is preferable that the curvature of the end surface 102a of the
upper blade 102 is greater than or equal to -0.20 mm -I and less than or equal to 0.07
mm-I.
[Examples]
[0037]
Next, examples performed in order to confirm the operation and effects of the
present invention will be described.
[0038]
(Example 1)
A processed material was manufactured by cutting off the end pm1ion 3 of the
plate material I by using the cutting device 1 00 according to the embodiment. · At this
time, the curvature (a reciprocal of a radius of curvature) of the cutting line 2 of the
plate material 1 was set to five levels of Conditions I to 5 in Table I below (Condition
3 shows a case where the cutting line 2 is linear). In Conditions 1 to 3 and 5 in Table
I, the width W of the top plate surface 1 05a of the falling-down prevention member
105 was set to 3 mm and the clearance CL!t was set to 25%. On the other hand, in
Condition 4 in Table 1, the width W of the top plate surface I 05a was set to 3 nun and
the clearance CL!t was set to two levels of 10% and 25%. As the plate material 1, a
steel plate having tensile strength of 980 MPa and a plate thickness of 1.4 mm was
- 17 -
used. The set load (a pressurizing force to the plate material!) of the falling-down
prevention member 105 was set to 5.0 kN.
Fmiher, for comparison, a processed material was likewise manufactured
using the cutting device 10 of the related ati shown in FIG. 8.
[0039]
[Table 1]
Condition 1
Condition 2
Condition 3
Condition 4
Condition 5
[0040]
Curvature [1/mm]
-0.09
-0.07
0
0.20
0.30
Radius of curvature
-11.1
-14.3
00
5.0
3.3
[mm]
Then, with respect to these processed materials, the cross section
perpendicular to the width direction was photographed and the burr height was
measured. The results are shown in FIGS. 3 and 4.
As shown in FIG. 3, in a comparative example, in a case where the clearance
CL/t is 25%, a large burr occuned, compared to a case where the clearance CL/t is
I 0%. On the other hand, in an example, even in a case where the clearance CL/t is
25%, a large burr did not occur. That is, in the example, even in a case where the
clearance CL/t is large, it could be confirmed that burr occurrence could be suppressed.
Further, also from the results shown in FIG. 4, it could be confirmed that in
the example, burr occurrence in the processed material could be suppressed.
However, in Condition 1, since the burr height due to the falling-down of the plate
material is small, it was found that the effect of falling-down prevention was smaller
than in Conditions 2 to 5.
[0041]
- 18 -
(Example 2)
Similar to the case of Example 1, a processed material was manufactured with
the cmvature of the cutting line 2 of the plate material 1 set to that in Condition 4 in
Table 1. The clearance CL!t was set to 25%, and the set load of the falling-down
prevention member lOS was set to four levels of 0.05 kN, 1.5 kN, 3.0 kN, and 5.0 kN.
Then, the stretch flanging was performed on these processed materials, and the relative
value (limit H/limit H reference) of a limit flange height was determined. The results
are shown in FIG. 5.
[0042]
FIG. 5 is a graph showing the relationship between the set load of the fallingdown
prevention member 105 and the relative value (limit H/limit_reference) of the
limit flange height. In FIG. 5, a plot in which the set load of the falling-down
prevention member is zero shows a case where the processed material manufactured
using the cutting device 10 of the related art is subjected to the stretch flanging.
The relative value (limit H/limit_reference) of the limit flange height is a
value obtained by dividing the limit flange height (limit H) in which a flange height is
increased at a pitch of about 1 nun and cracking of an edge portion or local necking in
the through-thickness direction does not occur, by the limit flange height (limit
H reference) of a processed material obtained under the condition of clearance
CL!t=lO% by using the cutting device 10 ofthe related ati.
Here, the "flange height" is the flange height of the p01tion excluding a rising
curvature p01tion at a root of a formed flange. Therefore, in a case where a flange
having the san1e height as the processed material obtained under the condition of
clearance CL!t=10% can be formed, the relative value (limit H/limit H_reference) of
the limit flange height is 1.0, and in a case where only a flange height to the eA'lent that
- 19 -
it does not come out from the rising curvature portion can be formed, the relative value
of the limit flange height is zero.
[0043]
A large burr was generated in the processed material manufactured by the
cutting device 10 of the related art. For this reason, as shown in FIG. 5, breakage
occurred when tltis processed material was subjected to the stretch flanging, and the
relative value of the limit flange height became zero.
On the other hand, in a case where the set load of the falling-down prevention
member was set to be greater than or equal to 0.05 kN, the relative value of the limit
flange height was more than 0.9 without occunence of a large burr. From this result,
it could be confirmed that in the cutting device I 00, a processed material having good
stretch flangeability could be manufactured even in a case where the clearance CUt is
as large as 25%.
[0044]
(Example 3)
Sintilar to the case of Example 2, a processed material was manufactured with
the curvature of the cutting line 2 of the plate material I set to that in Condition 4 in
Table I. The set load of the falling-down prevention member 105 was set to 5.0 kN
and the width W of the top plate surface 105a of the falling-down prevention member
I 05 was set to three levels of 3 mm, 6 mm, and 10 mm. Then, similar to the case of
Example 2, the relative value (limit H/limit_reference) of the limit flange height was
determined. The results are shown in FIG. 6.
[0045]
FIG. 6 is a graph showing the relationship between the width W of the top
plate surface 105a of the falling-down prevention member 105 and (limit
- 20 -
H/limit_reference). In FIG. 6, a plot in which the width of the falling-down
prevention member is zero shows a case where the processed material manufactured
using the cutting device 10 of the related att is subjected to the stretch flanging.
As shown in FIG. 6, a large burr was generated in the processed material
manufactured by the cutting device 1 0 of the related art. For this reason, breakage
occurred when this processed material was subjected to the stretch flanging, and the
relative value of the limit flange height became zero.
On the other hand, in the processed material manufactured by the cutting
device 100 according to the embodiment, the relative value (limit H/limit_reference) of
the limit flange height was about 1.0 without occurrence of a large burr. Also from
this result, it could be confirmed that in the cutting device 100, a processed material
having good stretch flangeability could be manufactured even in a case where the
clearance CL/t is as large as 25%.
[0046]
The embodiment of the present invention has been described above.
However, the above-described embodiment has been presented as an example, and the
scope of the present invention is not limited to only the above-described embodiment.
The above-described embodiment can be implemented in various other modes, and
various omissions, substitutions, and changes can be made within a scope which does
not depart from the gist of the invention. The above-described embodiment and
modifications thereof are included in the scope of the invention described in the claims
and the equivalents thereof as well as in the scope or the gist of the invention.
[0047]
For example, in the above-described embodiment, a case where the end
pmtion 3 in the longitudinal direction of the plate material I is cut off is shown.
- 21 -
However, the cutting device 100 may be configured so as to cut off an end pmiion in
the width direction of the plate material 1. Fmiher, the cutting device 100 may be
configured so as to cut off an end portion in a circumferential direction of the plate
material 1 (such that the cutting line 2 of the plate material! becomes one closed line).
[0048]
Fmihe1~ for example, in the above-described embodiment, a case where the
upper blade 102 has the pressing bar 109 and the elastic body 108 is shown. However,
the pressing bar 109 and the elastic body 108 may be provided in the falling-down
prevention member 105. Further, instead of the pressing bar 109 and the elastic body
I 08, a gas blowing device for blowing gas to the end pmiion of the plate material may
be provided.
[0049]
Further, for example, in the above-described embodiment, a case where the
cutting device I 00 is provided with a pair of upper blades 102 is shown. However,
the cutting device 100 may be provided with a single upper blade 102.
[0050]
Further, for example, in the above-described embodiment, a case where the
plate material I is cut in a curved line shape is sho\VIl. However, the plate material 1
may be cut in a linear fashion.
[0051]
Further, for example, in the above-described embodiment, a case where the
falling-down prevention member I 05 has the inclined surface I 05b is shown.
However, the inclined surface 1 05b may be a ve1iical surface. However, from the
viewpoint of securing a space for disposing the elastic body 107, the viewpoint of
improving the strength of the falling-down prevention member 105, and the like, it is
- 22 -
preferable that the inclined surface 1 05b is provided.
[Industrial Applicability]
[0052]
According to the present invention, it is possible to provide a cutting device
and a cutting method, in which occurrence of buns when cutting off an end portion of
a plate material can be easily suppressed at low cost.
[Brief Description of the Reference Symbols]
[0053]
1: plate material
2: cutting line
3: end portion of plate material
7: processed material
20: .press fonning device
100: cutting device
101: lower blade (first cutting blade)
102: upper blade (second cutting blade)
I 04: plate holder (first contact patt)
105: falling-down prevention member (second contact part)

[Document Type] CLAIMS
1. A cutting device for obtaining a processed material by cutting off an end
pmiion of a plate material by a first cutting blade and a second cutting blade which
relatively approach each other, the cutting device comprising:
a first contact pmi and the first cutting blade which clamp a processed
material portion to be the processed material, of the plate material, from front and back
surfaces thereof;
the second cutting blade and a second contact part which clamp an end
material portion to be the end portion, of the plate material, from front and back
sutfaces thereof; and
a drive part which causes the first cutting blade and the second cutting blade
to start relative approach each other while maintaining a flat state where the processed
material portion and the end material portion are on the same plane, on at least one of
the liont surface and the back surface of the plate material.
2. The cutting device according to claim 1, wherein a curved portion is
formed in each of the first cutting blade and the second cutting blade in a case of being
viewed in a direction in which the first cutting blade and the second cutting blade
approach each other.
3. The cutting device according to claim 2, wherein curvature of the curved
portion of the first cutting blade is greater than or equal to -0.07 mm -t and less than or
equal to 0.20 mm _,_
4. The cutting device according to any one of claims 1 to 3, wherein a
- 24 -
clearance between the first cutting blade and the second cutting blade is more than
I 0% and less than or equal to 30%.
5. The cutting device according to any one of claims I to 4, wherein a
pressurizing force of the second contact part with respect to the end material portion is
greater than or equal to 0.05 kN.
6. The cutting device according to any one of claims I to 5, wherein the
second contact part includes a flat portion which comes into contact with the end
material portion of the plate material.
7. The cutting device according to claim 6, wherein a minimum width
dimension of the flat portion is greater than or equal to a plate thickness of the plate
material.
8. The cutting device according to claim 6 or 7, wherein a maximum width
dimension of the flat portion is less than 0.5 times a minimum width dimension of the
end portion of the plate material.
9. The cutting device according to claim 6 or 7, wherein a maximum width
dimension of the flat portion is less than or equal to 30 mm.
10. The cutting device according to any one of claims I to 9, fmiher
comprising:
an end member removal pati which applies an external force to the end
. 25 .
p01iion after cutting of the plate material and after release of clamping of the end
p01iion by the second cutting blade and the second contact part.
II. A cutting method for obtaining a processed material by cutting off an
end portion of a plate material by a first cutting blade and a second cutting blade which
relatively approach each other, the cutting method comprising:
clamping a processed material portion to be the processed material, of the
plate material, from fi·ont and back surfaces thereof;
clamping an end material portion to be the end potiion, of the plate material,
from front and back surfaces thereof; and
causing the first cutting blade and the second cutting blade to start relative
approach each other while maintaining a flat state where the processed material portion
and the end material portion are on the same plane, on at least one of the front surface
and the back surface of the plate material.
12. The cutting method according to claim II, wherein tension is not
applied to either of the front surface or the back surface of the plate material at the
time of start of the approach.
13. The cutting method according to claim II or 12, wherein a clearance
between the first cutting blade and the second cutting blade is set to be more than I 0%
and less than or equal to 30%.
14. The cutting method according to any one of claims 11 to 13, wherein a
pressurizing force when clamping the end material potiion is set to be greater than or
- 26 -
equal to 0.05 kN.
15. The cutting method according to any one of claims 11 to 14, wherein the
plate material is a steel plate having tensile strength greater than or equal to 440 MPa.
16. The cutting method according to any one of claims 11 to 15, wherein a
plate thickness of the plate material is in a range of 0.6 mm to 3.6 mm.