HAVING RECESSES AND PROTRUSIONS
TECHNICAL FIELD
[0001] The present invention relates to a panel, and more particularly, to a
panel with high rigidity.
BACKGROUND ART
[0002] Panels used in automobiles or the like are required to be light·weight.
To provide a light·weight panel, the plate thickness may be reduced, for
example. However, reduced plate thickness leads to decreased rigidity. In
view of this, proposals haven been made to provide recesses and protrusions
to provide a certain rigidity without increasing plate thickness. The
recesses and protrusions are required to be shaped so as to improve rigidity
with the minimum depth in order to avoid contact with other components.
[0003] Japanese Patent No. 5218633 discloses a panel. The panel includes
a plurality of protrusions and a plurality of recesses. Each protrusion has a
flat top surface. Each-recess has a flat bottom surface. The protrusions
and recesses are in rows and columns, where the protrusions and recesses in
each row are arranged alternately and the protrusions and recesses in each
column are also arranged alternately.
[0004] JP 2012·51004A discloses a plate having recesses and protrusions.
This plate includes a plurality of protrusions and a plurality of recesses.
Each protrusion has a flat top surface. Each recess has a flat bottom
surface. Each of the top and bottom surfaces has a pair of extending
portions and a connecting portion connecting the extending portions. The
protrusions and recesses are in rows and columns, where the protrusions and
recesses in each row are arranged alternately and the protrusions and
recesses in each column are also arranged alternately. In plan view, each of
the extending portions of one of a top surface and a bottom surface is located
between the extending portions of the other.
[0005] Japanese Patent No. 4402745 discloses a heat insulator. The heat
insulator includes a large number of protrusions. Each protrusion is
hexagonal in shape in plan view, and the vertical cross section that passes
through opposite vertices is arc-shaped. The portions of the flat plate
located between the protrusions are not shaped as a straight line.
[0006] JP 2011·27248 A discloses a plate having recesses and protrusions.
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Applicant's Ref.: FP1<11814
Our Ref.:102W0144Pl
In this plate, each recess/protrusion includes a first region, a second region
and a third region with different protrusion heights as measured in the
thickness direction. These regions are distributed such that regions of the
same type are not arranged in a continuous manner and each region is
contact with two other regions of a different type.
[0007] JP 2011·101893 A discloses a plate having recesses and protrusions.
In this plate, each recess/protrusion has a first protruding portion, a second
protruding portion and an intermediate face. The first protruding portion is
shaped as a dodecagonal pyramid or a truncated dodecagonal pyramid. The
second protruding portion protrudes in a direction opposite to that of the first
protruding portion and is shaped as a hexagonal pyramid or a truncated
hexagonal pyramid. The intermediate face is a rectangular face provided in
the intermediate reference plane.
[0008] JP 2011·110847 A discloses a plate having recesses and protrusions.
This plate includes first columns each having first regions and intermediate
regions arranged alternately to form a straight line, and second regions and
intermediate regions. Such first and second columns are arranged
alternately. The first regions in a first column are adjacent to the
intermediate regions in a second column. The second regions in a second
column are adjacent to the intermediate regions in a first column. The first
and second regions are connected by first skirts. The intermediate regions
and first regions are connected by second skirts. The intermediate regions
and second regions are connected by third skirts.
[0009] JP 2011·110954 A discloses a vehicle panel. The vehicle panel
includes an interior panel. The interior panel includes recesses and
protrusions. Each recess/protrusion has a first protruding portion, a second
protruding portion and an intermediate face. The first protruding portion is
shaped as a dodecagonal pyramid or a truncated dodecagonal pyramid. The
second protruding portion protrudes in a direction opposite to that of the first
protruding portion and is shaped as a hexagonal pyramid or a truncated
hexagonal pyramid. The intermediate face is a rectangular face provided in
the intermediate reference plane.
DISCLOSURE OF THE INVENTION
[0010] The present inventors investigated the rigidities of the plates with
the recesses and protrusions described in the above publications. They
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Applicant's Ref.: FP141814
Our Rcf.:102W0144Pl
found out that the plates with the recesses and protrusions described in
Japanese Patent No. 5218633 and JP 2012·51004 A have improved rigidity
(stiffness) over the plates with the recesses and protrusions described in the
other publications. At the same time, they discovered that the recesses and
protrusions described in Japanese Patent No. 5218633 and JP 2012-51004 A
have the following disadvantages.
[0011] In the panel described in Japanese Patent No. 5218633, it is easy to
provide regions formed by flat faces divided by ridges. Thus, when a
torsional deformation occurs in the panel, the load propagates throughout
the panel since the ridges located at the borders between the recesses and
protrusions are shared, and a large in-plane shear is produced in every flat
face defined by the ridges such that an in-plane shear stress can easily be
produced uniformly in the entire panel. This provides a certain torsional
rigidity.
[0012] However, in the above panel, the recesses/protrusions are shallow
and the borders between the recesses and protrusions extend in rows and
columns. This results in a small second moment of area. As a result,
flexural rigidity is small. Particularly, second moment of area is at its
minimum at the borders between the protrusions and recesses such that
deformation can easily occur. That is, flexural rigidity decreases.
[0013] In the plate described in JP 2012-51004A, the borders between the
protrusions and recesses do not extend in rows and columns. This prevents
second moment of area from decreasing at the borders between the
protrusions and recesses. As a result, a bending deformation is unlikely to
occur at the borders between the protrusions and recesses. Since second
moment of area is high in any cross section, a certain flexural rigidity is
provided.
[0014] However, the regions formed by flat faces where a shear force occurs
in the plate are smaller than in the panel described in Japanese Patent No.
5218633. Thus, an in-plane shear stress is less likely to be produced
uniformly in the entire panel when a torsional deformation occurs. As such,
it is difficult to provide a certain torsional rigidity.
[0015] An object of the present invention is to provide a panel that
simultaneously provides a certain flexural rigidity and a certain torsional
rigidity.
[0016] A panel in an embodiment of the present invention includes a
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reinforcing unit. The reinforcing unit includes a plurality of first
rectangular regions and a plurality of second rectangular regions. The first
and second rectangular regions are in rows and columns, the first and second
rectangular regions in each row being arranged alternately and the first and
second rectangular regions in each column being arranged alternately.
Each of the first rectangular regions includes a first protrusion. The first
protrusion is fully-covering and protrudes in a first direction perpendicular
to an imaginary reference plane and has a flat top surface. Each of the
second rectangular regions includes a second protrusion and a reinforcing
protrusion. The second protrusion is partially-covering and protrudes in a
second direction opposite to the first direction and has a flat top surface.
The reinforcing protrusion extends between opposite sides and is
partially-covering and protrudes in the first direction and has a flat top
surface. The top surface of the reinforcing protrusion forms one face
together with the top surface of the first protrusion.
[0017] A panel in an embodiment of the present invention simultaneously
provides a certain flexural rigidity and a certain-torsionalrigidity.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] [FIG. 1] FIG. 1 a plan view of a panel in a first embodiment of the
present invention.
[FIG. 2] FIG. 2 is an enlarged plan view of some of the plurality of
reinforcing units included in the panel shown in FIG. 1.
3.
6.
[FIG. 3] FIG. 3 is a plan view of a reinforcing unit.
[FIG. 4] FIG. 4 is a cross-sectional view taken along line A-A of FIG.
[FIG. 5] FIG. 5 is a perspective view of the reinforcing unit of FIG. 3.
[FIG. 6] FIG. 6 is a plan view of a reinforcing unit.
[FIG. 7] FIG. 7 is a cross-sectional view taken along line B-B of FIG.
[FIG. 8] FIG. 8 is a perspective view of a panel illustrating flexural
rigidity and torsional rigidity.
[FIG. 9A] FIG. 9Ais a plan view of a panel of Comparative Example
1.
[FIG. 9B] FIG. 9B is a perspective view of the panel of Comparative
Example 1.
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Applicant's Ref.: FP141814
Our Ref.:l02W0144Pl
[FIG. lOAJ FIG. lOA is a plan view of a panel of Comparative
Example 2.
[FIG. lOB] FIG. lOB is a perspective view of the panel of
Comparative Example 2.
[FIG. 11] FIG. 11 is a plan view of the panel of the Inventive Example
with the top surfaces and bottom surfaces arranged diagonally.
[FIG. 12] FIG. 12 is a plan view of the panel of Comparative Example
1 with the top surfaces and bottom surfaces arranged diagonally.
[FIG. 13] FIG. 13 is a plan view of the panel of Comparative Example
2 with the top surfaces and bottom surfaces arranged diagonally.
[FIG. 14] FIG. 14 is a graph showing the results of simulations of
flexural rigidity and torsional rigidity with the top surfaces and bottom
surfaces arranged in a standard manner.
[FIG. 15] FIG. 15 is a graph showing the results of simulations of
flexural rigidity and torsional rigidity with the top surfaces and bottom
surfaces arranged diagonally.
[FIG. 16] FIG. 16 is a graph showing the results of simulations of
torsional rigidity with the top surfaces and bottom surfaces arranged in a
standard manner and diagonally.
[FIG. 17] FIG. 17 is an enlarged plan view of some of the plurality of
reinforcing units included in a panel in a second embodin:ient of the present
invention.
[FIG. 18] FIG. 18 is a plan view of a reinforcing unit.
[FIG. 19] FIG. 19 is a cross·sectional view taken along line C·C of
FIG. 18.
[FIG. 20] FIG. 20 is a plan view of a reinforcing unit.
[FIG. 21] FIG. 21 is a cross·sectional view taken along line D·D of
FIG. 20.
[FIG. 22] FIG. 22 is an enlarged plan view of some of the plurality of
reinforcing units included in a panel in a third embodiment of the present
invention.
[FIG. 23] FIG. 23 is a plan view of a reinforcing unit.
[FIG. 24] FIG. 24 is a cross·sectional view taken along line E· E of
FIG. 23.
[FIG. 25] FIG. 25 is a plan view of a reinforcing unit.
[FIG. 26] FIG. 26 is a cross·sectional view taken along line F·F of FIG.
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25.
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[FIG. 27] FIG. 27 is an enlarged plan view of some of the plurality of
reinforcing units included in a panel in a fourth embodiment of the present
invention.
[FIG. 28] FIG. 28 is an enlarged plan view of some of the plurality of
reinforcing units included in a panel in a fifth embodiment of the present
invention.
[FIG. 29] FIG. 29 is a plan view of a reinforcing unit.
[FIG. 30] FIG. 30 is a cross-sectional view taken along line G-G of
FIG. 29.
[FIG. 31] FIG. 31 is a plan view of a reinforcing unit.
[FIG. 32] FIG. 32 is a cross-sectional view taken along line H-H of
FIG.31.
[FIG. 33] FIG. 33 is an enlarged plan view of some of the plurality of
reinforcing units included in a panel in a sixth embodiment of the present
invention.
[FIG. 34] FIG. 34 is a plan view of a reinforcing unit.
[FIG. 35] FIG. 35 is a cross-sectional view taken along line I-I of FIG.
34.
[FIG. 36] FIG. 36 is a plan view of a reinforcing unit.
[FIG. 37] FIG. 37 is a cross-sectional view taken along line J-J of FIG.
36.
[FIG. 38] FIG. 38 is an enlarged plan view of some of the plurality of
reinforcing units included in a panel in a seventh embodiment of the present
invention.
[FIG. 39] FIG. 39 is a plan view of a reinforcing unit.
[FIG. 40] FIG. 40 is a cross-sectional view taken along line K-K of
FIG. 39.
[FIG. 41] FIG. 41 is a plan view of a reinforcing unit.
[FIG. 42] FIG. 42 is a cross-sectional view taken along line K-K of
FIG. 41.
EMBODIMENTS FOR CARRYING OUT THE INVENTION
[0019] A panel in an embodiment of the present invention includes a
reinforcing unit. The reinforcing unit includes a plurality of first
rectangular regions and a plurality of second rectangular regions. The fu·st
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Our Ref.:102WOH4Pl
and second rectangular regions are in rows and columns, the first and second
rectangular regions in each row being arranged alternately and the first and
second rectangular regions in each column being arranged alternately.
Each of the first rectangular regions includes a first protrusion. The first
protrusion is fully-covering and protrudes in a first direction perpendicular
to an imaginary reference plane and has a flat top surface. Each of the
second rectangular regions includes a second protrusion and a reinforcing
protrusion. The second protrusion is partially-covering and protrudes in a
second direction opposite to the first direction and has a flat top surface.
The reinforcing protrusion extends between opposite sides and is
partially-covering and protrudes in the first direction and has a flat top
surface. The top surface of the reinforcing protrusion forms one face
together with the top surface of the first protrusion.
[0020] In the panel described above, the top surface of a reinforcing
protrusion forms one face together with the top surface of a first protrusion.
That is, a reinforcing protrusion is formed integrally with a first protrusion
in a continuous manner. -This prevents second moment of area from
decreasing at the borders between the first and second rectangular regions.
As a result, a bending deformation is less likely to occur at the borders
between the first and second rectangular regions. Further, the second
rectangular regions include recesses and protrusions. This increases
second moment of area in a cross section that crosses the direction in which
the reinforcing protrusions extend. Thus, a bending deformation is less
likely to occur. That is, second moment of area is large in any cross section,
providing a certain flexural rigidity.
[0021] In an implementation where the top surface of a reinforcing
protrusion does not form one face together with the top surface of a first
protrusion, for example, the top surface of the reinforcing protrusion may be
located between an imaginary reference plane and the top surface of the first
protrusion. Then, the height of the reinforcing protrusion is small. Thus,
second moment of area decreases at the borders between the first and second
rectangular regions. As a result, a bending deformation can easily occur.
In contrast, in the panel described above, the top surface of a reinforcing
protrusion forms one face together with the top surface of a first protrusion.
This prevents second moment of area from decreasing. As a result, a
bending deformation is less likely to occur.
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Applicant's Ref.: FP1,1181'1
Our Rcf.:102WOH,1Pl
[0022] In the panel described above, the first and second rectangular regions
are in rows and columns, the first and second rectangular regions in each
row being arranged alternately and the first and second rectangular regions
in each column being arranged alternately. Thus, the top surfaces of the
first protrusions are arranged uniformly in a reinforcing unit. That is, in a
reinforcing unit, the flat faces defined by the ridges are disposed uniformly.
Thus, when a twisting deformation occurs, an in-plane shear stress can
easily be produced uniformly in the entire panel. That is, a certain
torsional rigidity is provided.
[0023] Preferably, each of the first rectangular regions and the second
rectangular regions is square in shape in plan view. In this case, the length
of one side of a flat face defined by ridges (more specifically, top surface of the
first protrusion) as measured in the row direction is equal to that as
measured in the column direction. Thus, substantially the same in-plane
shear stress is produced when a twisting deformation occurs about an axis
extending in the row direction and when a twisting deformation occurs about
an axis extending in the column direction. That is, substantially the same
torsional rigidity is produced when a twisting deformation occurs about an
axis extending in the row direction and when a twisting deformation occurs
about an axis extending in the column direction. In other words, the
anisotropy of torsional rigidity can be reduced.
[0024] Preferably, the ratio between the number of the first rectangular
regions and the number of the second rectangular regions ranges from 4:6 to
6:4. This simultaneously provides a certain flexural rigidity and a certain
torsional rigidity. The ratio between the number of the first rectangular
regions and the number of the second rectangular regions may be changed
within the above range such that, for example, the number of the first
rectangular regions is larger than the number of the second rectangular
regions when slightly greater importance is attached to torsional rigidity, or,
on the contrary, the number of the first rectangular regions is smaller than
the number of the second rectangular regions 14B when slightly greater
importance is attached to flexural rigidity.
[0025] Preferably, a plurality of reinforcing units are provided. The
plurality of reinforcing units are arranged in rows and/or columns. For two
adjacent reinforcing units, a top surface of a reinforcing protrusion of a
second rectangular region included in one reinforcing unit forms one face
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together with a top surface of a second protrusion of a second rectangular
region included in the other reinforcing unit or a top surface of a first
protrusion of a first rectangular region included in the other reinforcing unit.
[0026] This prevents second moment of area from decreasing at the borders
between one reinforcing unit and the other reinforcing unit.
[0027] In an implementation where the top surface of the reinforcing
protrusion of a second rectangular region included in one reinforcing unit
does not form one face together with the top surface of the second protrusion
of a second rectangular region included in the other reinforcing unit or the
top surface of the first protrusion of a first rectangular region included in the
other reinforcing unit, for example, the top surface of the reinforcing
protrusion in the one reinforcing unit may be located between an imaginary
reference plane and the top surface of the second protrusion or the top
surface of the first protrusion in the other reinforcing unit. Then, the
height of the reinforcing protrusion is small. Thus, second moment of area
decreases at the borders between the one reinforcing unit and the other
reinforcing-unit. In contrast, in the preferred aspect described above, the
top surface of the reinforcing protrusion in the one reinforcing unit forms one
face together with the top surface of the second protrusion or the top surface
of the first protrusion in the other reinforcing unit. This prevents second
moment of area from decreasing at the borders between the one reinforcing
unit and the other reinforcing unit.
[0028] Embodiments of the present invention will be described below with
reference to the drawings. The same or corresponding parts in the
drawings are labeled with the same characters and their description will not
be repeated.
[0029] [First Embodiment]
A panel 10 in a first embodiment of the present invention will be
described with reference to FIG. 1. The panel 10 includes a plurality of
reinforcing units. The plurality of reinforcing units include a plurality of
reinforcing units 12 and a plurality of reinforcing units 12A. The
reinforcing units 12 and 12A are in rows and columns, where the reinforcing
units 12 and 12A in each row are arranged alternately and the reinforcing
units 12 and 12A in each column are arranged alternately.
[0030] FIG. 2 is an enlarged view of four of the plurality of reinforcing units
included in the panel10, i.e. reinforcing units 12, 12, 12A and 12A arranged
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in two rows signal and two columns. The reinforcing units 12 and12A will
be described below.
[0031] [Reinforcing Unit 12]
As shown in FIG. 3, a reinforcing unit 12 includes a plurality of first
rectangular regions 14A and a plurality of second rectangular regions 14B.
As shown in FIG. 3, the first and second rectangular regions 14A and14B
are in rows and columns, where the first and second rectangular regions 14A
and 14B in each row are arranged alternately and the first and second
rectangular regions 14A and 14B in each column are arranged alternately.
In the reinforcing unit 12, the first and second rectangular regions 14A and
14B are arranged in three rows and three columns. The reinforcing unit 12
has more first rectangular regions 14A than second rectangular regions 14B.
[0032] Row direction as used herein means the direction of a row formed by
first and second rectangular regions 14A and 14B, and column direction as
used herein means the direction of a column formed by fi1·st and second
rectangular regions 14A and14B. The row direction is consistent with the
direction of a row of reinforcing units 12 and12A, and the column direction is
consistent with the direction of a row of reinforcing units 12 and12A.
[0033] [First Rectangular Region]
A first rectangular region 14Ais rectangular in shape in plan view.
In the implementation shown in FIG. 3, the first rectangular region 14A is
square in shape in plan view. As shown in FIG. 4, the first rectangular
region 14Aincludes a first protrusion 18. As shown in FIG. 4, the first
protrusion 18 protrudes in a direction perpendicular to an imaginary
reference plane 16 (for example, plane that passes through the center of the
panel as measured in the thickness direction as viewed looking at a side of
the panel) (hereinafter referred to as front direction). That is, the first
protrusion 18 protrudes away from the reference plane 16. The size of a
cross section of the first protrusion 18 parallel to the reference plane 16
gradually decreases as it goes away from the reference plane16.
[0034] As shown in FIGS. 3 to 5, the first protrusion 18 includes a top
surface 20 and four sides 22.
[0035] The top surface 20 is parallel to the reference plane 16. The top
surface 20 is square in shape in plan view.
[0036] Each side 22 is connected with the top surface 20. Each side 22 is
connected with the sides 22located around the top surface 20 and adjacent to
10
itself.
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[0037] Each side 22 is inclined relative to the reference plane 16. As the
inclination 8 of the side 22 relative to the reference plane 16 increases, the
rigidity is improved but localized decrease in plate thickness or cracking may
easily occur during molding. One may decide on an inclination 8 of the side
22 relative to the reference plane 16 taking into consideration how much
rigidity is to be improved, how easily the material can be molded and other
factors. When the material is steel, the inclination 8 is preferably in the
range of 15 to 60 degrees, and more preferably 45 degrees.
[0038] As shown in FIG. 4, the first rectangular region 14A further includes
a recess 24. The recess corresponds to the first protrusion 18 and is open
toward the back direction, which is opposite to the front direction.
[0039] [Second Rectangular Region]
A second rectangular region 14B is rectangular in shape in plan view.
In the implementation shown in FIG. 3, the second rectangular region14B is
square in shape in plan view. The shape and size of the second rectangular
region 14B in plan view are the same as those of the first rectangular region
14A. As shown in FIG. 4, the second rectangular region 14B includes a pair
of second protrusions 30 and a reinforcing protrusion 32.
[0040] As shown in FIG. 4, the second protrusions 30 protrude in the back
direction. That is, the second protrusions 30 protrude away from the
reference plane 16. The size of a cross section of each of the second
p1:otrusions 30 parallel to the reference plane 16 gradually decreases as it
goes away from the reference plane 16.
[0041] As shown in FIGS. 3 to 5, each second protrusion 30 includes a top
surface 34 and sides 36. Although not clear in FIGS. 3 to 5, there are four
sides 36.
[0042] The top surface 34 is parallel to the reference plane 16. The top
surface 34 is in the shape of a rectangle that extends in the column direction
in plan value. The top surface 34 is smaller than the top surface 20.
[0043] Each side 36 is connected with the top surface 34. Each side 36 is
connected with the sides 36 located around the top surface 34 and adjacent to
itself.
[0044] Each side 36 is inclined relative to the reference plane 16. The
inclination of the side 36 relative to the reference plane 16 is equal to the
inclination of the sides 22 relative to the reference plane 16.
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[0045] The second rectangular region 14B further includes recesses 38.
The recesses 38 correspond to the second protrusions 30 and are open toward
the front direction.
[0046] As shown in FIG. 4, the reinforcing protrusion 32 protrudes in the
front direction. That is, the reinforcing protrusion 32 protrudes away from
the reference plane 16. The size of a cross section of the reinforcing
protrusion 32 parallel to the reference plane 16 gradually decreases as it
goes away from the reference plane 16. The reinforcing protrusion 32 is
located between the two of the four sides of the second rectangular region
14B that extend in the column direction. That is, the reinforcing protrusion
32 extends in the column direction and is located between the pair of second
protrusions 30 in plan view.
[0047] As shown in FIGS. 3 to 5, the reinforcing protrusion 32 includes a top
surface 40 and a pair of sides 42.
[0048] The top surface 40 is parallel to the reference plane 16. The top
surface 40 is in the shape of a rectangle that extends in the column direction
in plan view. The top surface 40 is formed in a continuous manner with the
top surface 20 of a first protrusion 18. That is, the distance between the top
surface 40 and reference plane 16 is equal to the distance between the top
surface 20 and reference plane 16.
[0049] Each side 42 is connected with the top surface 40. Each side 42 is
connected with a side 22 of the first protrusion 18 of a first rectangular
region 14Alocated adjacent in the column direction. Each side 42 is formed
in a continuous manner with a side of a recess 38.
[0050] Each side 42 is inclined relative to the reference plane 16. The
inclination of the side 42 relative to the reference plane 16 is equal to the
inclination of the sides 22 relative to the reference plane 16.
[0051] The second rectangular region 14B further includes a recess groove
44. The recess groove 44 corresponds to the reinforcing protrusion 32 and is
open toward the back direction. The recess groove 44 is connected with the
recess 24 of an adjacent first rectangular region 14A. That is, the bottom
surface of the recess groove 44 is formed in a continuous manner with the
bottom surface of the recess 24. The sides of the recess groove 44 is formed
in a continuous manner with sides 36 of the second protrusions 30.
[0052] [Reinforcing Unit 12A]
A reinforcing unit 12A is obtained by turning a reinforcing unit 12
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over and rotating it by 90 degrees. In the reinforcing unit 12A, as shown in
FIGS. 6 and 7, the first protrusions 18 and reinforcing protrusions 32
protrude in the back direction and the second protrusions 30 protrude in the
front direction. In the reinforcing unit 12A, the reinforcing protrusions 32
extend in the row direction.
[0053] As shown in FIG. 2, the top surface 40 of the reinforcing protrusion
32 of a second rectangular region 14B in a reinforcing unit 12 is formed in a
continuous manner with the top surface 34 of a second protrusion 30 of a
second rectangular region 14B in a reinforcing unit 12A. Further, the
bottom surface of the recess groove 44 of a second rectangular region 14B in
a reinforcing unit 12A is formed in a continuous manner with the bottom
surface of a recess 38 of a second rectangular region 14B in a reinforcing unit
12. That is, although not shown, the top surface 40 of the reinforcing
protrusion 32 of a second rectangular region 14B in a reinforcing unit 12A is
formed in a continuous manner with the top surface 34 of a second
protrusion 30 of a second rectangular region 14B in a reinforcing unit 12.
[0054] The panel 10 includes a plurality of reinforcing units 12 and 12A.
This simultaneously provides a certain flexural rigidity and a certain
torsional rigidity. The reasons will be provided below.
[0055] First, flexural rigidity and torsional rigidity will be discussed with
reference to FIG. 8. Referring to FIG. 8, a panel PL has four sides 81 to 84.
Two ofthe four sides 81 to S4, S1 and S2, extend in the X·direction. The
two sides S3 and S4 extend in the Y.direction. The X·direction corresponds
to the row direction and the Y.direction corresponds to the column direction.
FIG. 8 shows the panel PL with the side S1 fixed. Flexural rigidity means
the difficulty of the panel PL being deformed when a displacement in the
Z-direction (i.e. displacement in a bending directionhs caused in the side S2
of the panel PL, which is parallel to the side Sl. Torsional rigidity means
the difficulty of the panel PL being deformed when a displacement about a
reference line SL extending in the Y.direction (i.e. displacement in a twisting
direction is caused). The reference line SL passes through the center C1 of
the panel PL and is perpendicular to the sides S1 and S2.
[0056] Referring to FIGS. 9A and 9B, a panel PL1 having reinforcing
portions such as those shown in these figures will be described. The sides
S1 to S4 shown in FIGS. 9A and 9B correspond to the sides S1 to S4 shown in
FIG. 8.
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Applicant's Ref.: FP14181•1
Our Ref.:l02W0144Pl
[0057] In the panel PLI, protrusions 50 each having a top surface 50A and
recesses 52 each having a bottom surface 52A are in rows and columns,
where such protrusions and recesses in each row are arranged alternately
and such protrusions and recesses in each column are arranged alternately.
Each of the top surfaces 50A and bottom surfaces 52A is square in shape in
plan view, and they are connected by sides 54.
[0058] It is assumed that a displacement in a twisting direction is caused in
the panel PLl with the side Sl fixed, similar to the panel of FIG. 8. In the
panel PLl, the top surfaces 50A and bottom surfaces 52A are arranged in a
grid and share ridges located at the borders between the recesses and
protrusions. Thus, when a displacement in a twisting direction occurs, the
load propagates throughout the panel through the shared ridges and an
in-plane shear stress is produced in the top surfaces 50A and bottom surfaces
52A. That is, when a displacement in a twisting direction occurs, an
in-plane shear stress can be produced uniformly in the entire panel PLl.
Thus, the panel PLl has high torsional rigidity.
[0059] Referring to FIGS. lOA and lOB, a panel PL2 having reinforcing
portions such as those shown in these figures will be described. The sides
Sl to S4 shown in FIGS. lOA and lOB correspond to the sides Sl to S4 shown
in FIG. 8.
[0060] In the panel PL2, protrusions 60 each having a top surface 64 and
recesses 62 each having a bottom surface 66 are in rows and columns, where
such protrusions and recesses in each row are arranged alternately and such
protrusions and recesses in each column are arranged alternately. Each top
surface 64 includes a pair of extending portions 64A and a connecting portion
64B connecting them. Each bottom surface 66 includes a pair of extending
portions 66A and a connecting portion 66B connecting them. The top
surfaces 64 and bottom surfaces 66 are connected by sides 68.
[0061] It is assumed that, similar to the situation of FIG. 8, a displacement
in a bending direction is caused in the panel PL2 with the side Sl fixed. In
the panel PL2, the second moment of area in the XZ-plane perpendicular to
theY-direction can be prevented from decreasing at any position in the
Y-direction. This provides a certain flexural rigidity.
[0062] As discussed above, the panel PLl has high torsional rigidity, while
the panel PL2 has high flexural rigidity. However, the panels PLl and PL2
suffer from the following problems.
14
English translation of specification of PCT/JP2014/081064
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Our Ref.:102W0144P1
[0063] The panel PL1 has shallow square recesses/protrusions such that
second moment of area is small, particularly at tho borders between the
protrusions 50 and rocesses 52. Thus, when a displacement in a bending
direction occurs, a bending deformation may occur, particularly at the
borders between the protrusions 50 and recesses 52. That is, the panel PL1
has characteristics that are particularly advantageous in terms of torsional
rigidity, and has a flexural rigidity that is much lower than its torsional
rigidity.
[0064] In the panel PL2, it is difficult to provide a large area for each of the
top and bottom surfaces 64 and 66. Thus, when a displacement in a
twisting direction occurs, in-plane shear stress is unlikely to be produced
uniformly in the entire panel PL2. As a result, a twisting deformation can
occur. That is, the panel PL2 has characteristics that are particularly
advantageous in terms of flexural rigidity, and has a torsional rigidity that is
much lower than its flexural rigidity.
[0065] In contrast, in the panel10, in every one of the plurality of
reinforcing units 12 and 12A, first and second rectangular regions 14A and
14B are in rows and columns, where the first and second rectangular regions
14A and 14B in each row are arranged alternately and first and the first and
second rectangular regions 14A and 14B in each column are arranged
alternately. That is, in every one of the plurality of reinforcing units 12 and
12A, the top surfaces 20 are arranged uniformly. Thus, flat faces defined by
ridges are present uniformly in all the reinforcing units 12 and 12A. As a
result, when a twisting deformation occurs, in·plane shear stress can easily
be produced uniformly in the entire panel10. That is, a certain torsional
rigidity is provided.
[0066] In the panellO, a top surface 40 forms one face together with a top
surface 20 in all the reinforcing units 12 and 12A. Thus, in all the
reinforcing units 12, second moment of area can be prevented from
decreasing at the borders, in the column direction, between the first and
second rectangular regions 14A and 14B. As a result, in all the reinforcing
units 12, a bending deformation is unlikely to occur at the borders, in the
column direction, between the first and second rectangular regions 14A and
14B. Further, in all the reinforcing units 12A, second moment of area can
be prevented from decreasing at the borders, in the row direction, between
the first and second rectangular regions 14Aand 14B. As a result, in all the
15
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Our Ref.:102W0144Pl
reinforcing units 12A, a bending deformation is unlikely to occur at the
borders, in the row direction, between the first and second rectangular
regions 14A and 14B. In addition, in all the reinforcing units 12 and 12A,
the second rectangular regions 14B have recesses and protrusions. Thus,
second moment of area in a cross section that crosses the direction in which
the reinforcing protrusions 32 extend is large. As a result, a bending
deformation is unlikely to occur. That is, second moment of area is large in
any cross section. As such, a certain flexural rigidity can be provided.
[0067] In the panel10, the top surface 40 of the reinforcing protrusion 32 of
a second rectangular region 14B in a reinforcing unit 12 is formed in a
continuous manner with the top surface 34 of a second protrusion 30 of a
second rectangular region 14B in a reinforcing unit 12A. Further, the top
surface 40 of the reinforcing protrusion 32 of a second rectangular region
14B in a reinforcing unit 12A is formed in a continuous manner with the top
surface 34 of a second protrusion 30 of a second rectangular region 14B in a
reinforcing unit 12. This prevents second moment of area fi·om decreasing
at the borders between the reinforcing units 12 and 12A. As a result, a
bending deforniation is unlikely to occur at the borders between the
reinforcing units 12 and 12A.
[0068] In the panel 10, in every one of the reinforcing units 12 and 12A, the
ratio of the number of first rectangular regions 14A and the number of
second rectangular regions 14B is 5:4. That is, in the present embodiment,
in every one of the reinforcing units 12 and 12A, the number of first
rectangular regions ·14A and the number of second rectangular regions 14B
are substantially equal, or more particularly, the ratio of these numbers is in
the range of 4:6 to 6:4. This simultaneously provides a certain flexural
rigidity and a certain torsional rigidity.
[0069] In the panel10, in all the reinforcing units 12 and 12A, the first and
second rectangular regions 14A and 14B are square in shape in plan view.
In this case, the length of one side of a flat face defined by ridges (more
specifically, top surface 20) as measured in the row direction is equal to that
as measured in the column direction. Thus, substantially the same in·plane
shear stress is produced when a twisting deformation occurs about an axis
extending in the row direction and when a twisting deformation occurs about
an axis extending in the column direction. That is, substantially the same
torsional rigidity is produced when a twisting deformation occurs about an
lG
English translation of specification of PCT/JP201,1/081064
Applicant's Ref.: FP141814
Our Ref.:l02W0144Pl
axis extending in the row direction and when a twisting deformation occurs
about an axis extending in the column direction. In short, the present
embodiment can reduce the anisotropy of torsional rigidity.
[0070] The flexural rigidity and torsional rigidity of a panel having
reinforcing portions as shown in FIG. 2 (hereinafter referred to as panellO of
the Inventive Example) were evaluated using FEM analysis. For
comparison, FEM analysis was similarly conducted for a panel having
reinforcing portions as shown in FIGS. 9A and 9B (hereinafter referred to as
panel PLl of Comparative Example 1) and a panel having reinforcing
portions as shown in FIGS. lOA and lOB (hereinafter referred to as panel
PL2 of Comparative Example 2).
[0071] [Conditions for FEM Analysis]
For FEM analysis, a commercially available, general-purpose
program code LS-DYNA ver. 971 was used. The element type was complete
integral shell element. The element si7.e was a square with a side 1 mm
long. To evaluate rigidity, the static implicit method for solving a balance
-equation of forces was selected for use. The panel was made of a material
corresponding to JAC270D. The Young's modulus was 206 GPa. The
Poisson's rate was 0.30. The 0.2 % yield strength was 183 MPa. The
tensile strength was 308 MPa. The n value was 0.20. The panel had
shaped as a square with a side 470 mm long. The thickness of the panel
was 0.6 mm.
[0072] [Panel of Inventive Example]
Referring to FIG. 2, in the panel of the Inventive Example, a first
rectangular region 14Ahad a side with a length (Ll in FIG. 2) of 50 mm. A
top surface 20 had a side with a length (L2 in FIG. 2) of 42.5 mm. A
reinforcing unit had a side with a length (L3 in FIG. 2) of 150 mm. A top
surface 40 had a width (WI in FIG. 2) of 5 mm. The recess/protrusion depth
(H in FIG. 4) was 5 mm.
[0073] [Panel of Comparative Example 1]
In the panel PLI of Comparative Example 1, the recess/protrusion
depth was 3 nun. A top surface 50Ahad a side with a length (Ll in FIG. 9A)
of 27 mm. A protrusion 50 had a side with a length (L2 in FIG. 9A) of 30
llllll.
[007 4] [Panel of Comparative Example 2]
In the panel PL2 of Comparative Example 2, the recess/protrusion
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Our Ref.:l02W0144Pl
depth was 3 mm. A bottom surface 6G had a length as measured in the row
direction (Ll in FIG. lOA) of 35 mm. The distance between the connecting
portions G4B of the protrusion GO located adjacent to a recess 62 in the row
direction (L2 in FIG. lOA) was 45 mm. The length of an extending portion
GGA of a recess G2 as measured in the column direction (Wl in FIG. lOA) was
19mm. The length of the connecting portion G4B of a protrusion GO (W2 in
FIG. lOA) was 29 nun.
[0075] [Arrangements of Top and Bottom Surfaces]
Flexural rigidity and torsional rigidity were evaluated for a standard
arrangement and a diagonal arrangement of top and bottom surfaces. Top
and bottom surfaces arranged in a standard manner (hereinafter referred to
as standard arrangement) are shown in FIGS. 2, 9A and lOA. Top and
bottom surfaces arranged diagonally (hereinafter referred to as diagonal
arrangement) are shown in FIGS. 11, 12 and 13. That is, the direction in
which the protrusions and recesses are arranged in the diagonal
arrangement is rotated by 45 degrees from that for the standard
arrangement.
[0076] [Method of Evaluating Flexural Rigidity]
Flexural rigidity was evaluated by using a load-displacement curve
obtained when one side of each panel (i.e. side Sl shown in FIGS. 2, 9A, lOA,
11, 12 and 13) was fixed and a load of 1 N was applied to the side parallel to
the one side (i.e. side S2 shown in FIGS. 2, 9A, lOA, 11, 12 and 13).
[0077] [Method of Evaluating Torsional Rigidity]
Torsional rigidity was evaluated by using a load-displacement curve
obtained when one side of each panel (i.e. side Sl shown in FIGS. 2, 9A, lOA,
11, 12 and 13) was fixed and one twisting deformation was caused in a side
perpendicular to the one side (i.e. side S3 shown in FIGS. 2, 9A, lOA, 11, 12
and 13).
[0078] [Results from FEM Analysis]
FIG. 14 is a graph showing values of flexural rigidity and torsional
rigidity from FEJVI analysis in the standard arrangement. FIG. 15 is a
graph showing values of flexural rigidity and torsional rigidity from FEM
analysis in the diagonal arrangement. In these graphs, the value N of the
rate of increase in flexural rigidity relative to a flat plate indicates that the
panel has a flexural rigidity N times that of a flat plate, and the value M of
the rate of increase in torsional rigidity relative to a flat plate indicates that
18
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Applicant's Ref.: FP141814
Our Ref.:102W0144Pl
the panel has a torsional rigidity M times that of a flat plate.
[0079) As shown in FIG. 14, for the panel PL1 of Comparative Example 1,
the torsional rigidity was higher than the flexural rigidity and the torsional
rigidity was far higher than that of a flat plate. That is, the panel PL1 of
Comparative Example 1 had characteristics particularly advantageous in
terms of torsional rigidity.
[0080) For the panel PL2 of Comparative Example 2, the flexural rigidity
was higher than the torsional rigidity and the flexural rigidity was far higher
than that of a flat plate. That is, the panel PL2 of Comparative Example 2
had characteristics particularly advantageous in terms of flexural rigidity.
[0081) For the panel 10 of the Inventive Example, the torsional rigidity was
lower than that of the panel PL1 of Comparative Example 1, but the flexural
rigidity was higher. For the panellO of the Inventive Example, the flexural
rigidity was lower than that of the panel PL2 of Comparative Example 2, but
the torsional rigidity was higher. For the panellO of the Inventive Example,
the difference between the improvement in torsional rigidity over a flat plate
and the improvement in flexural rigidity over a flat plate was smaller than
those for the panels PLl and PL2 of Comparative Examples 1 and 2.
[0082) As shown in FIG. 15, for the panel PL1 of Comparative Example 1,
the flexural rigidity was higher than the torsional rigidity and the difference
between them was quite large. That is, the panel PL1 of Comparative
Example 1, when in the diagonal arrangement, had characteristics
particularly advantageous in terms of flexural rigidity. In other words, the
panel PL1 of Comparative Example 1 had characteristics particularly
advantageous in terms of flexural rigidity or torsional rigidity depending on
whether it was in the standard arrangement or in the diagonal arrangement.
In short, for the panel PL1 of Comparative Example 1, a significant
difference in flexural rigidity and torsional rigidity was produced by the
relationship between the direction in which the protrusions 50 and recesses
52 were arranged and the bending or twisting direction for deformation.
[0083) For the panel PL2 of Comparative Example 2, the flexural rigidity
was higher than the torsional rigidity not only when the panel was in the
standard arrangement but also when it was in the diagonal arrangement.
For the panel PL2 of Comparative Example 2, the difference between the
torsional rigidity and flexural rigidity was much smaller than that for the
standard arrangement. That is, for the panel PL2 of Comparative Example
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2, a significant difference in torsional rigidity was produced by the
relationship between the direction in which the protrusions 60 and recesses
62 were arranged and the bending or twisting direction for deformation.
[0084] For the panel 10 of the Inventive Example, the flexural rigidity was
higher than the torsional rigidity when the panel was in the diagonal
arrangement. That is, the panel 10 of the Inventive Example had
characteristics particularly advantageous in terms of flexural rigidity or
torsional rigidity depending on whether it was in the standard arrangement
or in the diagonal arrangement. The difference between the flexural
rigidity and torsional rigidity for the standard arrangement was
substantially equal to that for the diagonal arrangement. That is, for the
panel 10 of the Inventive Example, the difference between the flexural
rigidity and torsional rigidity was small regardless of the relationship
between the direction in which the first and second rectangular regions 14A
and 14B were arranged and the bending or twisting direction for
deformation.
[0085] As can be apparent from the above discussion, the panellO of the
Inventive Example simultaneously provided a certain torsional rigidity and
a certain flexural rigidity regardless of the relationship between the
direction in which the protrusions and recesses were arranged and the
bending or twisting direction for bending as compared with the panels PL1
and PL2 of Comparative Examples 1 and 2.
[0086] FIG. 16 is a graph showing values of torsional rigidity from FEM
analysis for the standard arrangement and values of torsional rigidity from
FEM analysis for the diagonal arrangement. In this graph, the value M of
the rate of increase in torsional rigidity relative to a flat plate indicates that
the panel has a torsional rigidity M times that of a flat plate.
[0087] As shown in FIG. 16, for the panel PL1 of Comparative Example 1,
the torsional rigidity for the standard arrangement was much higher than
that for the diagonal arrangement. That is, torsional rigidity differed
significantly depending on whether the panel was in the standard
arrangement or in the diagonal arrangement.
[0088] For the panel PL2 of Comparative Example 2, the torsional rigidity
for the diagonal arrangement was higher than that for the standard
arrangement.
[0089] For the panel 10 of the Inventive Example, the torsional rigidity for
20
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Our Ref.:l02W0144Pl
the standard arrangement was higher than that for the diagonal
arrangement. The panel10 of the Inventive Example had a higher
torsional rigidity when in the diagonal arrangement than that of the panel
PL1 of Comparative Example 1. The panel10 of the Inventive Example had
a higher torsional rigidity when in the standard arrangement than that of
the panel PL2 of Comparative Example 2. It had a substantially equal
torsional rigidity when in the diagonal arrangement. For the panel 10 of
the Inventive Example, the difference between the torsional rigidity for the
standard arrangement and the torsional rigidity for the diagonal
arrangement was smaller than those for the panels PL1 and PL2 of
Comparative Examples 1 and 2.
[0090] As can be apparent from the above discussion, the panel10 of the
Inventive Example had reduced anisotropy in torsional rigidity compared
with the panels PL1 and PL2 of Comparative Examples 1 and 2.
[0091] [Second Embodiment]
A plurality of reinforcing units included in a panel in a second
embodiment of the present invention will be described with reference to
FIGS. 17 to 21. The plurality of reinforcing units include a plurality of
reinforcing units 12B and a plurality of reinforcing units 12C. The
reinforcing units 12B and 12C are in rows and columns, where the
reinforcing units 12B and 12C in each row are arranged alternately and the
reinforcing units 12B and 12C in each column are arranged alternately.
FIG. 17 shows two rows and two columns of reinforcing units 12B and 12C.
[0092] [Reinforcing Unit 12B]
A reinforcing unit 12B will be described with reference to FIGS. 18
and 19. The reinforcing unit 12B has first rectangular regions 14A and
second rectangular regions 14B in three rows and three columns. Unlike
the reinforcing unit 12, the reinforcing unit 12B has fewer first rectangular
regions 14A than second rectangular regions 14B. In the reinforcing unit
12B, the reinforcing protrusions 32 extend in the column direction.
[0093] [Reinforcing Unit 12C]
A reinforcing unit 12C will be described with reference to FIGS. 20
and 21. The reinforcing unit 12C is obtained by turning a reinforcing unit
12B over and rotating it by 90 degrees. In the reinforcing unit 12C, the first
protrusions 18 and reinforcing protrusions 32 protrude in the back direction
and the second protrusions 30 protrude in the front direction. In the
21
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Our Ref.:l02W0144Pl
reinforcing unit 12C, the reinforcing protrusions 32 extend in the row
direction.
[0094] As shown in FIG. 17, the top surface 40 of the reinforcing protrusion
32 of a second rectangular region 14B in a reinforcing unit 12B is formed in a
continuous manner with the top surface 34 of a second protrusion 30 of a
second rectangular region 14B in a reinforcing unit 12C. The bottom
surface of the recess groove 44 of a second rectangular region 14B in a
reinforcing unit 12C is formed in a continuous manner with the bottom
surface of a recess 38 of a second rectangular region 14B in a reinforcing unit
12B. That is, although not shown, the top surface 40 of the reinforcing
protrusion 32 of a second rectangular region 14B in a reinforcing unit 12C is
formed in a continuous manner with the top surface 34 of a second
protrusion 30 of a second rectangular region 14B of a reinforcing unit 12B.
[0095] There are two positions at each of which the top surface 40 of the
reinforcing protrusion 32 of a second rectangular region 14B in a reinforcing
unit 12B is formed in a continuous manner with the top surface 34 of a
second pmtrusion 30 of a second rectangular region 14B in-a reinforcing unit
12C. Further, there are two positions at each of which the top surface 40 of
the reinforcing protrusion 32 of a second rectangular region 14B in a
reinforcing unit 12C is formed in a continuous manner with the top surface
34 of a second protrusion 30 of a second rectangular region 14B in a
reinforcing unit 12B. Thus, a bending deformation is less likely to occur at
the borders between adjacent reinforcing units than in the first embodiment.
[0096] [Third Embodiment]
A plurality of reinforcing units included in a panel in a third
embodiment of the present invention will be described with reference to
FIGS. 22 and 26. The plurality of reinforcing units include a plurality of
reinforcing units 12B, a plurality of reinforcing units 12C, a plurality of
reinforcing units 12D and a plurality of reinforcing units 12E. The
reinforcing units 12B and 12C are in rows, where the reinforcing units 12B
and 12C in each row are arranged alternately; the reinforcing units 12D and
12E are in rows, where the reinforcing units 12D and 12E in each row are
arranged alternately; the reinforcing units 12B and 12D are in columns,
where the reinforcing units 12B and 12D in each column are arranged
alternately; and the reinforcing units 12C and 12E are in columns, where the
reinforcing units 12C and 12E in each column are arranged alternately.
22
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FIG. 22 shows two rows and two columns of reinforcing units 12B, 12C, 12D
and12E.
[0097] [Reinforcing Unit 12D]
A reinforcing unit 12D will be described with reference to FIGS. 23
and 24. Unlike in a reinforcing unit 12, in the reinforcing unit 12D, the
reinforcing protrusions 32 extend in the row direction.
[0098] [Reinforcing Unit 12E]
A reinforcing unit 12E will be described with reference to FIGS. 25
and 26. The reinforcing unit 12E is obtained by turning a reinforcing unit
12D over and rotating it by 90 degrees. In the reinforcing unit 12E, the first
protrusions 18 and reinforcing protrusions 32 protrude in the back direction
and the second protrusions 30 protrude in the front direction. In the
reinforcing unit 12E, the reinforcing protrusions 32 extend in the column
direction.
[0099] The top surface 40 of the reinforcing protrusion 32 of a second
rectangular region 14B in a reinforcing unit 12B is formed in a continuous
manner with the top surface 20 of the first protrusion 18 of a first
rectangular region 14Ain a reinforcing unit 12D. The bottom surface of the
recess groove 44 of a second rectangular region 14B in a reinforcing unit 12C
is formed in a continuous manner with the bottom surface of a recess 38 of a
second rectangular region 14B in a reinforcing unit 12B. That is, although
not shown, the top surface 40 of the reinforcing protrusion 32 of a second
rectangular region 14B in a reinforcing unit 12C is formed in a continuous
manner with the top surface 34 of a second protrusion 30 of a second
rectangular region 14B in a reinforcing unit 12B. The top surface 40 of the
reinforcing protrusion 32 of a second rectangular region 14B in a reinforcing
unit 12D is formed in a continuous manner with the top surface 34 of the
second protrusion 30 of a second rectangular region 14B in a reinforcing unit
12E. The bottom surface of the recess groove 44 of a second rectangular
region 14B in a reinforcing unit 12E is formed in a continuous manner with
the bottom surface of the recess 24 of a first rectangular region 14A in a
reinforcing unit 12C. That is, although not shown, the top surface 40 of the
reinforcing protrusion 32 of a second rectangular region 14B in a reinforcing
unit 12E is formed in a continuous manner with the top surface 20 of the
first protrusion 18 of a first rectangular region 14A in a reinforcing unit 12C.
[0100] There are two positions at each of which the top surface 40 of the
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Our Ref.:l02W0144Pl
reinforcing protrusion 32 of a second rectangular region 14B in a reinforcing
unit 12B is formed in a continuous manner with the top surface 20 of the
first protrusion 18 of a first rectangular region 14A in a reinforcing unit 12D.
Further, there are two positions at each of which the top surface 40 of the
reinforcing protrusion 32 of a second rectangular region 14B in a reinforcing
unit 12C is formed in a continuous manner with the top surface 34 of a
second protrusion 30 of a second rectangular region 14B in a reinforcing unit
12B. Thus, deformation is less likely to occur at the borders between
adjacent reinforcing units than in the first embodiment.
[0101] [Fourth Embodiment]
A plurality of reinforcing units included in a panel in a fourth
embodiment of the present invention will be described with reference to FIG.
27. The plurality of reinforcing units include a plurality of reinforcing units
12, a plurality of reinforcing units 12A, a plurality of reinforcing units 12B
and a plurality of reinforcing units 12C. The reinforcing units 12 and 12A
are in columns, where the reinforcing units 12 and 12A in each column are
arranged alternately; the reinforcing units 12B and 12C are in columns,
where the reinforcing units 12B and 12C in each column are arranged
alternately; the reinforcing units 12 and 12B are in rows, where the
reinforcing units 12 and 12B in each row are arranged alternately; and the
reinforcing units 12A and 12C are in rows, where the reinforcing units 12A
and 12C in each row are arranged alternately. FIG. 27 shows two rows and
two columns of reinforcing units 12, 12A, 12B and 12C.
[0102] The top surface 40 of the reinforcing protrusion 32 of a second
rectangular region 14B in a reinforcing unit 12 is formed in a continuous
manner with the top surface 34 of a second protrusion 30 of a second
rectangular region 14B in a reinforcing unit 12A. The bottom surface of the
recess groove 44 of a second rectangular region 14B in a reinforcing unit 12A
is formed in a continuous manner with the bottom surface of the recess 24 of
a first rectangular region 14A in a reinforcing unit 12C. That is, although
not shown, the top surface 40 of the reinforcing protrusion 32 of a second
rectangular region 14B in a reinforcing unit 12A is formed in a continuous
manner with the top surface 20 of the first protrusion 18 of a first
rectangular region 14Ain a reinforcing unit 12C. The bottom surface of the
recess groove 44 of a second rectangular region 14B in a reinforcing unit 12C
is formed in a continuous manner with the bottom surface of the recess 24 of
24
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Our Ref.:I02W0144Pl
a first rectangular region 14A in a reinforcing unit 12A. That is, although
not shown, the top surface 40 of tho reinforcing protrusion 32 of a second
rectangular region 14B in a reinforcing unit 12C is formed in a continuous
manner with the top surface 20 of the first protrusion 18 of a first
rectangular region 14A in a reinforcing unit 12A. The top surface 40 of the
reinforcing protrusion 32 of a second rectangular region 14B in a reinforcing
unit 12B is formed in a continuous manner with the top surface 34 a second
protrusion 30 of a second rectangular region 14B in a reinforcing unit 12C.
[0103] There are two positions at each of which the top surface 40 of the
reinforcing protrusion 32 of a second rectangular region 14B in a reinforcing
unit 12B is formed in a continuous manner with the top surface 20 of the
first protrusion 18 of a first rectangular region 14A in a reinforcing unit 12C.
Further, there is one position at which the top surface 40 ofthe reinforcing
protrusion 32 of a second rectangular region 14B in a reinforcing unit 12 is
formed in a continuous manner with tho top surface 34 of a second
protrusion 30 of a second rectangular region 14B in a reinforcing unit 12A.
Further, there are two positions at each of which the top surface 40 ofthe
reinforcing protrusion 32 of a second rectangular region 14B in a reinforcing
unit 12C is formed in a continuous manner with the top surface 20 of the
first protrusion 18 of a first rectangular region 14A in a reinforcing unit 12.
Furthermore, there is one position at which the top surface 40 of the
reinforcing protrusion 32 of a second rectangular region 14B in a reinforcing
unit 12A is formed in a continuous manner with the top surface 20 of the first
protrusion 18 of a first rectangular region 14A in a reinforcing unit 12C.
Thus, deformation is less likely to occur at the borders between adjacent
reinforcing units (especially the borders between the reinforcing units 12A
and 12C and the borders between the reinforcing units 12B and 12C) than in
the first embodiment.
[0104] [Fifth Embodiment]
A plurality of reinforcing units included in a panel in a fifth
embodiment of the present invention will be described with reference to
FIGS. 28 to 32. The plurality of reinforcing units include a plurality of
reinforcing units 12F, a plurality of reinforcing units 12G 1 and a plurality of
reinforcing units 12G2. The reinforcing units 12F and 12G 1 are in rows
and columns, where the reinforcing units 12 and 12G1 in each row are
arranged alternately and the reinforcing units 12 and 12G 1 in each column
25
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are arranged alternately. The reinforcing units 12F and 12G2 are in rows
and column, where the reinforcing units 12F and 12G2 in each row are
arranged alternately and the reinforcing units 12F and 12G2 in each column
are arranged alternately. The reinforcing units 12G1 and 12G2 are in
diagonal series, where the reinforcing units 12G1 and 12G2 in each diagonal
series are arranged alternately. FIG. 28 shows two rows and two columns of
reinforcing units 12F, 12G1 and 12G2.
[0105] [Reinforcing Unit 12F]
A reinforcing unit 12F will be described with reference to FIGS. 29
. and 30. Unlike in a reinforcing unit 12, in the reinforcing unit 12F, two of
the four reinforcing protrusions 32 extend in the row direction.
[0106] [Reinforcing Unit 12G 1]
A reinforcing unit 12G1 will be described with reference to FIGS. 31
and 32. Unlike in a reinforcing unit 12B, in the reinforcing unit 12G1, one
of the five reinforcing protrusions 32 extends in the row direction.
[0107] [Reinforcing Unit 12G2]
A reinforcing unit 12G2 is obtained by rotating a reinforcing unit
12G 1 by 90 degrees.
[0108] The top surface 40 of the reinforcing protrusion 32 of a second
rectangular region 14B in a reinforcing unit 12F is formed in a continuous
manner with the top surface 20 of the first protrusion 18 of a first
rectangular region 14A in a reinforcing unit 12G 1. The top surface 40 of the
reinforcing protrusion 32 of a second rectangular region 14B in a reinforcing
unit 12G 1 or 12G2 is formed in a continuous manner with the top surface 20
of the first protrusion 18 of a first rectangular region 14A in a reinforcing
unit 12F. The top surface 40 of the reinforcing protrusion 32 of a second
rectangular region 14B in a reinforcing unit 12G2 is formed in a continuous
manner with the top surface 20 of the first protrusion 18 of a first
rectangular region 14A in a reinforcing unit 12F. The top surface 40 of the
reinforcing protrusion 32 of a second rectangular region 14B in a reinforcing
unit 12F is formed in a continuous manner with the top surface 20 ofthe first
protrusion 18 of a first rectangular region 14A in a reinforcing unit 12G2.
[0109] Each of the reinforcing units 12F, 12G1 and 12G2 has one or more
reinforcing protrusions 32 extending in the row direction and one or more
reinforcing protrusions 32 extending in the column direction. This prevents
second moment of area from decreasing at the borders, in the column
26
English translation of specification of PCT/JPZOH/081064
Applicant's Ref.: FP141814
Our Ref.:102W0144Pl
direction, between the first and second rectangular regions 14A and 14B in
each of the reinforcing units 12F, 12Gl and 12G2, and prevents second
moment of area from decreasing at the borders, in the row direction, between
the first and second rectangular regions 14A and 14B. Thus, a bending
deformation is unlikely to occur at these borders.
[0110] [Sixth Embodiment]
A plurality of reinforcing units included in a panel in a sixth
embodiment of the present invention will be described with reference to
FIGS. 33 to 37. The plurality of reinforcing units include a plurality of
reinforcing units 12H and a plurality of_reinforcing units 12I. The
reinforcing units 12H and 12I are in rows and column, where the reinforcing
units 12H and 12I in each row are arranged alternately and the reinforcing
units 12H and 12I in each column are arranged alternately. FIG. 33 shows
two rows and two columns of reinforcing units 12H and 12I.
[0111] [Reinforcing Unit 12H]
A reinforcing unit 12H will be described with reference to FIGS. 34
and 35. The reinforcing unit 12H has two first rectangular regions 14A and
two second rectangular regions 14B disposed in two rows and two columns.
That is, in the reinforcing unit 12H, the first and second rectangular regions
14A and 14B in each row are arranged alternately and the first and second
rectangular regions 14A and 14B in each column are arranged alternately.
Further, in the reinforcing unit 12H, the reinforcing protrusion 32 of each
second rectangular region 14B extends in the column direction.
[0112] [Reinforcing Unit 12I]
A reinforcing unit 12I will be described with reference to FIGS. 36
and 37. The reinforcing unit 12I is obtained by turning a reinforcing unit
12H over and changing the direction in which the reinforcing protrusion 32
of each second rectangular region 14B extends to the row direction.
[0113] The top surface 40 of the reinforcing protrusion 32 of a second
rectangular region 14B in a reinforcing unit 12I is formed in a continuous
manner with the top surface 34 of a second protrusion 30 of a second
rectangular region 14B in a reinforcing unit 12H. The bottom surface of the
recess groove 44 of a second rectangular region 14B in a reinforcing unit 12H
is formed in a continuous manner with the bottom surface of a recess 38 of a
second rectangular region 14B in a reinforcing unit 12I. That is, although
not shown, the top surface 40 of the reinforcing protrusion 32 of a second
27
English translation of specification of PCT/JP20H/0810G4
Applicant's Ref.: FPH1814
Our Ref.:102W0144Pl
rectangular region 14B in a reinforcing unit 12H is formed in a continuous
manner with the top surface 34 of a second protrusion 30 of a second
rectangular region 14B in a reinforcing unit 12I.
[0114] [Seventh Embodiment]
A plurality of reinforcing units included in a panel in a seventh
embodiment of the present invention will be described with reference to
FIGS. 38 to 42. The plurality of reinforcing units include a plurality of
reinforcing units 12J and a plurality of reinforcing units 12K. The
reinforcing units 12J and 12K are in rows and columns, where the
reinforcing units 12J and 12K in each row are arranged alternately and the
reinforcing units 12J and 12K in each column are arranged alternately.
FIG. 38 shows two rows and two columns of reinforcing units 12J and 12K.
[0115] [Reinforcing Unit 12J]
A reinforcing unit 12J will be described with reference to FIGS. 39
and 40. Tho reinforcing unit 12J is obtained by rotating a reinforcing unit
12H by 90 degrees.
[0116] [Reinforcing Unit 12K]
A reinforcing unit 12K will be described with reference to FIGS. 41
and 42. The reinforcing unit 12K is obtained by rotating a reinforcing unit
121 by 90 degrees.
[0117] The top surface 40 ofthe reinforcing protrusion 32 of a second
rectangular region 14B in a reinforcing unit 12K is formed in a continuous
manner with the top surface 34 of a second protrusion 30 of a second
rectangular region 14B in a reinforcing unit 12J. The bottom surface of the
recess groove 44 of a second rectangular region 14B in a reinforcing unit 12J
is formed in a continuous manner with the bottom surface of a recess 38 of a
second rectangular region 14B in a reinforcing unit 12K. That is, although
not shown, the top surface 40 of the reinforcing protrusion 32 of a second
rectangular region 14B in a reinforcing unit 12J is formed in a continuous
manner with the top surface 34 of a second protrusion 30 of a second
rectangular region 14B in a reinforcing unit 12K.
[0118] Although embodiments of the present invention have been described
in detail, these embodiments are merely examples and the present. invention
is not limited in any way to the above embodiments.
[0119] The shape and use of the panel is not limited to any particular ones
as long as the panel includes a portion where a reinforcing unit can be
28
formed.
English translation of specification of PCT/JP2014/08106•1
Applicant's Ref.: FP14181<1
Our Ref.:l02W0144Pl
For example, the panel may be used as a panel component in a
floor panel, door interior panel, dash panel, trunk lid interior panel, hood
interior panel or other panels of an automobile, or may be used as a member
constituting a part of the frame of an automobile. Alternatively, the panel
may be used as a building material or used in consumer electronics. The
panel may include a flat frame-shaped portion that surrounds all the
reinforcing units. The panel may be joined to another member using this
frame-shaped portion. Reinforcing units may be present along edges of the
panel. In this case, parts of the reinforcing units may be cut off. The panel
may be made of, for example, a metal such as steel, aluminum alloy, titanium
and stainless steel, or a synthetic resin.
[0120] The panel is only required to have reinforcing units in portions where
a certain strength is needed. For example, it is advantageous if some
portions of the edges of the panel of FIG. 1 are flat if the panel is expected to
be joined to another member or subjected to another treatment such as
bending or cutting.
[0121] The arrangement of reinforcing units is determined depending on the
shape and size of the portions of the panel where the reinforcing units are to
be provided, for example. Reinforcing units may be provided on a flat
surface or a curved surface. If the panel is made of metal, reinforcing units
can be easily formed by plastic working such as press working or rolling.
The panel may be heated to improve the formability of the panel, for example
by warm pressing or hot stamping, and then subjected to press working. If
the panel is made of a synthetic resin, reinforcing units can be easily formed
by injection molding or hot stamping.
[0122] The panel need not include a plurality of reinforcing units. For
example, the panel may include one reinforcing unit.
[0123] A second rectangular region may include a plurality of reinforcing
protrusions. This will further prevent second moment of area from
decreasing at the borders between the first and second rectangular regions
compared with implementations where a second rectangular region includes
only one reinforcing protrusion. As a result, a bending deformation is still
less likely to occur at the borders between the first and second rectangular
regwns.
[0124] In the embodiments described above, the first and second
rectangular regions 14A and 14B are arranged in two rows and two columns
29
English translation of specification of PCT/JP2014/08106'1
Applicant's Ref.: FP1418H
Our Ref.:l02W01HP1
or in three rows and three cohmu1s; however, the arrangement of first and
second rectangular regions 14A and 14B is not limited to these arrangements.
For example, an arrangement may have four or more rows and columns.
Further, the number of rows may be different from the number of columns.
The arrangement of fn·st and second rectangular regions 14A and 14B is
determined depending on the shape and size of the portions of the panellO
where the reinforcing units are to be provided, for example.
30
English translation of specification of PCT/JP2014/081064
Applicant's Ref.: FP141814
Our Ref.:102W0144Pl

CLAIMS
1. A panel comprising a reinforcing unit including a plurality of
first rectangular regions and a plurality of second rectangular regions,
wherein:
the first and second rectangular regions are in rows and columns, the
first and second rectangular regions in each row being arranged alternately
and the first and second rectangular regions in each column being arranged
alternately,
each of the first rectangular regions includes a fully-covering first
protrusion protruding in a first direction perpendicular to an imaginary
reference plane and having a flat top surface,
each of the second rectangular regions includes:
a partially-covering second protrusion protruding in a second
direction opposite to the first direction and having a flat top smfacc; and
a partially-covering reinforcing protrusion extending between
opposite sides and protruding in the first direction and having a flat top
surface, and
the top surface of the reinforcing protrusion forms one face together
with the top surface of the first protrusion.
2. The panel according to claim 1, wherein one reinforcing
protrusion extends along a row and another reinforcing protrusion extends
along a column.
3. The panel according to claim 1 or 2, wherein a number of the first
rectangular regions is larger than a number of the second rectangular
regwns.
4. The panel according to claim 1 or 2, wherein a ratio between a
number of the first rectangular regions and a number of the second
rectangular regions ranges from 4:6 to 6:4.
5. The panel according to any one of claims 1 to 4, wherein each of
the first rectangular regions and the second rectangular regions is square in
shape in plan view.
31
I
6.
English translation of specification of PCT/JP2014/081064
Applicant's Ref.: FP141814
Our Ref.:102W0144Pl
The panel according to any one of claims 1 to 5, wh~rein:
a plurality of reinforcing units are provided,
the plurality of reinforcing units are arranged in rows and/or
columns, and,
for two adjacent reinforcing units, a top surface of a reinforcing
protrusion of a second rectangular region included in one reinforcing unit
forms one face together with a top surface of a second protrusion of a second
rectangular region included in the other reinforcing unit or a top surface of a
first protrusion of a first rectangular region includ13d in the other reinforcing
unit. 1
7.~ The panel according to claim 6, wherein:
the reinforcing protrusion of the second rectangular region included
in the one reinforcing unit extends along a row, and
a reinforcing protrusion of the second rectangular region included in
the other reinforcing unit extends along a column.
. J
8. The panel according to claim 6 or 7, wherein each of the
reinforcing units has three rows and three columns of first and second
rectangular regions.
9. The panel according to claim 8, wherein five first rectangular
regions are provided and four second rectangular regions are provided.
10. The panel according to claim.8, wherein four first rectargular
regions are provided and five second rectangular regions are provided.
11. The panel according to claim 6 or 7, wherein each of the
reinforcing units has two rows and two columns of first and second
rectangular regions.
12. The panel according to claim 11, wherein two first rectangular
regions are provided and two second rectangular regions are provided.