TECHNICAL FIELD
[0001]
The present disclosure relates to a stiffened panel structure.
BACKGROUND ART
[0002]
An automobile includes panel-shaped components such as outer
panels and the like. Such panel-shaped components are required to have
sufficiently high flare rigidity. Some stiffened panel structures for
automobile doors, which have enhanced flare rigidity, have been known (see,
for example, Japanese Patent Application Publication No. 2019-156384
(Patent Literature 1) and Japanese Patent Application Publication No. 2018-
016171 (Patent Literature 2). In the present specification, a panel-shaped
component used for an automobile door will be referred to as a door panel in
some cases.
[0003]
FIG. 28 is a sectional view of an example of a conventional stiffened
structure 301. FIG. 29 is another example of a conventional stiffened
structure 301. In each of FIG. 28 and FIG. 29, a yet-to-be-finished stiffened
structure 301 is depicted in an upper section, and a finished stiffened
structure 301 is depicted in a lower section.
[0004]
The stiffened structure 301 shown in FIG. 28 includes a door panel
302 including a panel body 321. A reinforcing member 303 is stuck to the
inner surface 321a of the panel body 321. The reinforcing member 303 is
entirely bonded to the panel body 321. This ensures sufficient flare rigidity
of the panel body 321.
[0005]
The reinforcing member 303 is made of resin. Before baking
finishing, the reinforcing member 303 is bonded onto the inner surface 321a
2
2
of the panel body 321 (see upper section of FIG. 28). The reinforcing member
303 bonded to the panel body 321 is hardened by heat at the time of baking
finishing and adheres tightly to the panel body 321.
[0006]
Usually, the door panel 302 including the panel body 321 is made of
steel. The reinforcing member 303, which is made of resin, and the door
panel body 321, which is made of steel, greatly differ in coefficient of linear
expansion. Accordingly, when heat is applied to the door panel 302 with the
reinforcing member 303 bonded thereto during baking finishing, the
reinforcing member 303 and the panel body 321 have different deformation
amounts. Therefore, the panel body 321 undergoes elastic deformation and
may further undergo plastic deformation in some cases. This causes the
panel body 321 to have pits and projections 322 (see lower section of FIG. 28).
Thus, regarding the stiffened structure shown in FIG. 28, the surface quality
of the door panel 302 may be degraded.
[0007]
Regarding the stiffened structure 301 shown in FIG. 29, however, the
reinforcing member 303A bonded onto the inner surface 321a of the panel
body 321 is made of steel. Therefore, the reinforcing member 303A and the
panel body 321 are not different in coefficient of linear expansion. Then, it
never happens that the heat at the time of baking finishing leads to
degradation of the surface quality of the door panel 302.
[0008]
In this case, however, it is necessary to strictly manage the
dimensional accuracy of the reinforcing member 303A. If a reinforcing
member with low dimensional accuracy is bonded to the panel body 321 as
the reinforcing member 303A (see upper section of FIG. 29), the panel body
321 undergoes elastic deformation along the shape of the reinforcing member
303A and may further undergo plastic deformation in some cases (see lower
section of FIG. 29). Thus, even the stiffened structure 301 shown in FIG. 29
can have a problem of low surface quality of the door panel 302.
CITATION LIST
PATENT LITERATURES
[0009]
3
3
[Patent Literature 1] Japanese Patent Application Publication No.
2019-156384
[Patent Literature 2] Japanese Patent Application Publication No.
2018-016171
SUMMARY OF INVENTION
TECHNICAL PROBLEM
[0010]
As described above, conventional stiffened structures have a problem
of low surface quality of a panel-shaped component. When a panel-shaped
component has low surface quality, the flare rigidity of the panel-shaped
component may not be so enhanced as expected.
[0011]
An object of the present disclosure is to provide a stiffened panel
structure in which the panel-shaped component has sufficient surface quality
and improved flare rigidity.
SOLUTION TO PROBLEM
[0012]
A stiffened panel structure according to the present disclosure
includes a panel-shaped component and a wire. The panel-shaped
component includes a panel body that curves in such a manner as to be convex
outward. The wire has a first end portion and a second end portion. The
first end portion is bonded to a first point on an inner surface of the panel
body. The second end portion is bonded to a second point on the inner surface
of the panel body. The wire is strained between the first point and the second
point.
[0013]
Another stiffened panel structure according to the present disclosure
includes a panel-shaped component, an auxiliary component, and a wire.
The panel-shaped component includes a panel body that is flat or curves in
such a manner as to be convex outward. The auxiliary component is
positioned inside the panel-shaped component and integrated with the panelshaped
component. The wire has a first end portion and a second end
portion. The first end portion is bonded to a first point on an inner surface
4
4
of the panel body. The second end portion is bonded to the auxiliary
component. The wire is strained between the first point and the auxiliary
component.
[0014]
Another stiffened panel structure according to the present disclosure
includes a panel-shaped component, a supporting member, and a wire. The
panel-shaped component includes a panel body that is flat or curves in such
a manner as to be convex outward. The supporting member projects from
an inner surface of the panel body. The wire has a first end portion and a
second end portion. The first end portion is bonded to a first point on the
inner surface of the panel body. The second end portion is bonded to a second
point on the inner surface of the panel body, the second point being opposed
to the first point with the supporting member in between. The wire is
strained between the first point and the second point via the supporting
member.
EFFECT OF INVENTION
[0015]
The present disclosure provides a stiffened panel structure in which
the panel-shaped component has sufficient surface quality and improved flare
rigidity.
BRIEF DESCRIPTION OF DRAWINGS
[0016]
[FIG. 1] FIG. 1 is a sectional view of a stiffened panel structure
according to a first embodiment.
[FIG. 2] FIG. 2 is a plan view of the stiffened panel structure according
to the first embodiment.
[FIG. 3] FIG. 3 is a diagram showing the way of attaching each wire
to a panel body in the stiffened panel structure according to the first
embodiment.
[FIG. 4A] FIG. 4A is a perspective view of a panel-shaped component
with no wires attached thereto when a load is applied to the panel-shaped
component.
[FIG. 4B] FIG. 4B is a perspective view of a panel-shaped component
5
5
with no wires attached thereto when a load is applied to the panel-shaped
component.
[FIG. 4C] FIG. 4C is a diagram showing deformation behaviors of a
panel body with no wires attached thereto when a load is applied to the panelshaped
component.
[FIG. 5] FIG. 5 is a diagram showing the stiffened panel structure
according to the first embodiment when a load is applied from outside to the
panel-shaped component.
[FIG. 6] FIG. 6 is a plan view of a stiffened panel structure according
to a second embodiment.
[FIG. 7] FIG. 7 is a plan view of a stiffened panel structure according
to a third embodiment.
[FIG. 8] FIG. 8 is a chart showing results of a first load test on the
stiffened panel structures of the second and third embodiments.
[FIG. 9] FIG. 9 is a chart showing results of a second load test on the
stiffened panel structures of the second and third embodiments.
[FIG. 10] FIG.10 is a sectional view of a stiffened panel structure
according to a fourth embodiment.
[FIG. 11] FIG. 11 is a sectional view of a stiffened panel structure
according to a fifth embodiment.
[FIG. 12] FIG. 12 is a plan view of a stiffened panel structure
according to a sixth embodiment.
[FIG. 13] FIG. 13 is a sectional view of a part of the stiffened panel
structure according to the sixth embodiment.
[FIG. 14] FIG. 14 is a plan view of a stiffened panel structure
according to a seventh embodiment.
[FIG. 15] FIG. 15 is a plan view of a stiffened panel structure
according to an eighth embodiment.
[FIG. 16] FIG. 16 is a sectional view of a stiffened panel structure
according to a ninth embodiment.
[FIG. 17] FIG. 17 is a plan view of the stiffened panel structure
according to the ninth embodiment.
[FIG. 18] FIG. 18 is a sectional view of a stiffened panel structure
according to a tenth embodiment.
[FIG. 19] FIG. 19 is a plan view of a stiffened panel structure
6
6
according to an eleventh embodiment.
[FIG. 20] FIG. 20 is a chart showing results of a third load test on the
stiffened structure of the eleventh embodiment.
[FIG. 21] FIG. 21 is a sectional view of a stiffened panel structure
according to a twelfth embodiment.
[FIG. 22] FIG. 22 is a sectional view of a stiffened panel structure
according to a thirteenth embodiment.
[FIG. 23] FIG. 23 is a sectional view of a stiffened panel structure
according to a fourteenth embodiment.
[FIG. 24] FIG. 24 is a sectional view of a stiffened panel structure
according to a fifteenth embodiment.
[FIG. 25] FIG. 25 is a sectional view of a stiffened panel structure
according to a sixteenth embodiment.
[FIG. 26] FIG. 26 is a sectional view of a stiffened panel structure
according to a seventeenth embodiment.
[FIG. 27] FIG. 27 is a chart showing results of a fourth load test on
the stiffened structure according to the seventeenth embodiment.
[FIG. 28] FIG. 28 is a sectional view of an example of a conventional
stiffened structure.
[FIG. 29] FIG. 29 is a sectional view of another example of a
conventional stiffened structure.
DESCRIPTION OF EMBODIMENTS
[0017]
Some embodiments of the present disclosure will hereinafter be
described. In the following paragraphs, some embodiments of the present
disclosure will be described by giving examples; however, the present
disclosure is not limited to those examples. In the following paragraphs,
specific values and materials may be given as examples; however, the present
disclosure is not limited to those examples.
[0018]
In order to attain the object above, the inventors conducted studies,
and as a result, the inventors made the following findings.
[0019]
Panel-shaped components are required to have high flare rigidity.
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7
Flare rigidity is evaluated based on the amount of elastic deformation of a
panel-shaped component caused by application of a load thereto from outside.
Specifically, when a load is applied to a panel body of a panel-shaped
component from outside inward, the loaded part elastically deforms in the
loading direction. The smaller the elastic deformation amount, the higher
the flare rigidity.
[0020]
Possible ways to enhance the flare rigidity of a panel-shaped
component are increasing the sheet thickness of the panel-shaped component
and attaching a reinforcing member to the panel body.
[0021]
The flare rigidity of a panel-shaped component increases and
decreases with the cube of the sheet thickness. Accordingly, if the sheet
thickness is decreased for the purpose of weight saving, the flare rigidity
greatly decreases. Even if the material is selected for the purpose of
heightening the strength of the panel-shaped component, it is not so effective
as to enhance the flare rigidity. It is because the flare rigidity is evaluated
based on elastic deformation amount.
[0022]
On the other hand, when a reinforcing member is bonded to the panel
body, there are problems as described above.
[0023]
As described above, in a conventional stiffened panel structure, a
reinforcing member is bonded to the inner surface of the panel body in such a
manner as to be entirely stuck to the panel body. In this case, the junction
area between the panel body and the reinforcing member is large. When the
junction area is large, the shape of the panel body greatly depends on the
properties (coefficient of linear expansion, shape and size) of the reinforcing
member. Accordingly, the panel body is likely to undergo plastic deformation
depending on the properties of the reinforcing member.
[0024]
Thus, it can be said that degradation of the surface quality of a panelshaped
component in a conventional stiffened structure is caused by a large
junction area between a panel body and a reinforcing member. Then, it can
be said that a small junction area between a panel body and a reinforcing
8
8
member maintains the surface quality of the panel-shaped component. In
order to decrease the junction area between a panel body and a reinforcing
member, only end portions of the reinforcing member should be bonded to the
panel body.
[0025]
Stiffened panel structures according to embodiments of the present
disclosure have been invented on the basis of the above-described findings.
[0026]
A stiffened panel structure according to an embodiment of the present
disclosure includes a panel-shaped component and a wire. The panel-shaped
component includes a panel body that curves in such a manner as to be convex
outward. The wire has a first end portion and a second end portion. The
first end portion is bonded to a first point on the inner surface of the panel
body. The second end portion is bonded to a second point on the inner surface
of the panel body. The wire is strained between the first point and the second
point. (This configuration will be referred to as first configuration.)
[0027]
For the panel-shaped component of the stiffened panel structure with
the first configuration, there is no particular requirement except having a
panel body that curves in such a manner as to be convex outward. Typically,
the panel-shaped component is an outer panel for an automobile. The outer
panel is, for example, a door outer panel, a hood (bonnet), a roof, a fender, or
the like.
[0028]
There are no limits to the material of the wire. Typically, the wire is
a metal wire. The material of the metal wire is not particularly limited.
For example, the metal wire is a steel wire. The metal wire may be a single
wire or a stranded wire. The wire may be a CFRP (carbon fiber reinforced
plastic) wire. The CFRP wire may be a CFRP strand or a CFRP gut. The
CFRP may be thermosetting CFRP that contains thermosetting resin (e.g.,
epoxy) as the base material or may be thermoplastic CFRP that contains
thermoplastic resin (e.g., polyamide) as the base material. Preferably,
closed-chain carbon fiber is used for the CFRP wire.
[0029]
The diameter of the wire (metal wire, CFRP wire, or the like) is
9
9
arbitrarily chosen according to the design requirements. When the wire has
a non-circular cross-section, the diameter of a circle of which the area is equal
to the cross-sectional area of the wire (equivalent diameter) is defined as the
diameter of the wire. In order to suppress an increase in weight while
securing sufficient rigidity of the wire, the diameter of the wire is desirably
0.3 mm to 3.0 mm. More desirably, the diameter of the wire is 1.1 mm to 2.5
mm.
[0030]
In the stiffened panel structure with the first configuration, the first
end portion of the wire is bonded to the first point of the panel body, and the
second end portion of the wire is bonded to the second point of the panel body.
Thus, the wire is bonded to the panel body at the first end portion and the
second end portion. Then, the wire is strained between the first point and
the second point. In this case, the wire extends linearly between the first
point and the second point. The wire extending between the first point and
the second point is out of contact with the inner surface of the panel body.
[0031]
A panel body of a panel-shaped component installed in an automobile
is likely to be subjected to a load from outside. In the following paragraphs,
regarding a panel-shaped component, a point onto which a load is expected to
be applied from outside will be referred to as "expected load point" in some
cases. When a load is applied to the expected load point of a panel body, the
panel body bends. Specifically, the expected load point of the panel body is
displaced in the loading direction. In other words, the expected load point of
the panel body is deformed inward. With the deformation of the expected
load point, a part of the panel body that is off from the expected load point is
deformed outward. This part will hereinafter be referred to as "outward
deformation area". The outward deformation area is displaced in a direction
that is opposite to the loading direction and away from the expected load point.
In a sectional view of a panel-shaped component, there are outward
deformation areas on both sides of the expected load point.
[0032]
In the stiffened panel structure with the first configuration, the wire
is strained between the first point and the second point. The first point and
the second point are respectively in separated outward deformation areas.
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10
In this case, when a load is applied to the panel body, the wire is subjected to
tensile force. At the same time, the first point and the second point of the
panel body receive, from the wire, reaction force to the tensile force. This
suppresses deformation of the panel body at the first point and the second
point. With the suppression of deformation at the first point and the second
point, deformation of the expected load point is suppressed. In this way, the
flare rigidity of the panel-shaped component is enhanced. Thus, the wire
functions as a kind of a reinforcing member.
[0033]
In the stiffened panel structure with the first configuration, the wire,
which functions as a reinforcing member, is bonded to the panel body only at
the first end portion and the second end portion. Accordingly, the junction
area between the panel body and the wire is small.
[0034]
Therefore, in the stiffened panel structure with the first configuration,
the shape of the wire does not affect the shape of the panel body so strongly
as in a conventional stiffened panel structure in which a reinforcing member
is entirely bonded to a panel body, and it is no longer necessary to strictly
manage the dimensional accuracy of the wire (reinforcing member). When
heat is applied to the panel body and the wire during aftertreatment or the
like, the coefficient of linear expansion of the wire does not affect the shape of
the panel body so strongly, regardless of whether the material of the wire and
the material of the panel body are of the same kind or different kinds. Hence,
the surface quality of the panel-shaped component can be maintained.
[0035]
The stiffened panel structure with the first configuration is preferably
configured as follows. The panel body includes an expected load point onto
which a load is expected to be applied from outside, a first area, and a second
area. Without the wire, the first area and the second area are expected to be
displaced in directions opposite to a loading direction and away from the
expected load point when a load is applied to the expected load point from
outside. The second area is opposed to the first area with the expected load
point in between. The first point is in the first area, and the second point is
in the second area. (This configuration will be referred to as second
configuration.)
11
11
[0036]
In the stiffened panel structure with the second configuration, the
first area and the second area correspond to the above-described outward
deformation areas. In this case, the surface quality of the panel-shaped
component can be maintained more certainly, and the flare rigidity of the
panel-shaped component can be enhanced more.
[0037]
A stiffened panel structure according to another embodiment of the
present disclosure includes a panel-shaped component, an auxiliary
component, and a wire. The panel-shaped component includes a panel body
that is flat or curves in such a manner as to be convex outward. The
auxiliary component is positioned inside the panel-shaped component and
integrated with the panel-shaped component. The wire has a first end
portion and a second end portion. The first end portion is bonded to a first
point on an inner surface of the panel body. The second end portion is bonded
to the auxiliary component. The wire is strained between the first point and
the auxiliary component. (This configuration will be referred to as third
configuration.)
[0038]
In the stiffened panel structure with the third configuration, a panelshaped
component as used in the stiffened panel structure with the first
configuration is usable as the panel-shaped component. In the stiffened
panel structure with the third configuration, however, the panel body, to
which the wire is bonded, curves in such a manner as to be convex outward
or is flat.
[0039]
For the auxiliary component, there is no particular requirement
except being positioned inside the panel-shaped component and integrated
with the panel-shaped component. For example, when the panel-shaped
component is a door outer panel, the auxiliary component is a door inner
panel, a door impact beam, or the like.
[0040]
In the stiffened panel structure with the third configuration, a wire
as used in the stiffened panel structure with the first configuration is usable
as the wire.
12
12
[0041]
In the stiffened panel structure with the third configuration, the first
end portion of the wire is bonded to the first point of the panel body, and the
second end portion of the wire is bonded to the auxiliary component. Thus,
the wire is bonded to the panel body at the first end portion and is bonded to
the auxiliary component at the second portion. Then, the wire is strained
between the first point and the auxiliary component. In this case, as in the
stiffened panel structure with the first configuration, the wire extends
linearly between the first point and the auxiliary component. Moreover, the
wire extending between the first point and the auxiliary component is out of
contact with the inner surface of the panel body.
[0042]
In the stiffened panel structure with the third configuration, the wire
is strained between the first point and the auxiliary component. The first
point is in the outward deformation area. Then, when a load is applied to
the panel body, the wire is subjected to tensile force. Meanwhile, the first
point of the panel body receives, from the wire, reaction force to the tensile
force. This suppresses deformation of the panel body at the first point.
With the suppression of the deformation at the first point, deformation of the
expected load point is suppressed. In this way, the flare rigidity of the panelshaped
component is enhanced. Thus, in the stiffened panel structure with
the third configuration also, the wire functions as a kind of a reinforcing
member.
[0043]
In the stiffened panel structure with the third configuration, the wire,
which functions as a reinforcing member, is bonded to the panel body only at
the first end portion and is bonded to the auxiliary component only at the
second end portion. Accordingly, as in the stiffened panel structure with the
first configuration, the junction area between the panel body and the wire is
small. Therefore, the surface quality of the panel-shaped component can be
maintained.
[0044]
The stiffened panel structure with the third configuration is
preferably configured as follows. The panel body includes an expected load
point onto which a load is expected to be applied from outside, and a first area.
13
13
Without the wire, the first area is expected to be displaced in a direction
opposite to a loading direction and away from the expected load point when a
load is applied to the expected load point from outside. The first point is in
the first area. (This configuration will be referred to as fourth
configuration.)
[0045]
In the stiffened panel structure with the fourth configuration, the first
area corresponds to the outward deformation area described above. In this
case, the surface quality of the panel-shaped component can be maintained
more certainly, and the flare rigidity of the panel-shaped component can be
enhanced more.
[0046]
A stiffened panel structure according to another embodiment of the
present disclosure includes a panel-shaped component, a supporting member,
and a wire. The panel-shaped component includes a panel body that is flat
or curves in such a manner as to be convex outward. The supporting
member projects from an inner surface of the panel body. The wire has a
first end portion and a second end portion. The first end portion is bonded
to a first point on the inner surface of the panel body. The second end portion
is bonded to a second point on the inner surface of the panel body, the second
point being opposed to the first point with the supporting member in between.
The wire is strained between the first point and the second point via the
supporting member. (This configuration will be referred to as fifth
configuration.)
[0047]
In the stiffened panel structure with the fifth configuration, a panelshaped
component as used in the stiffened panel structure with the first
configuration is usable as the panel-shaped component. In the stiffened
panel structure with the fifth configuration, however, the panel body, to which
the wire is bonded, curves in such a manner as to be convex outward or is flat,
as in the third configuration.
[0048]
For the supporting member, there is no particular requirement except
projecting from the inner surface of the panel body. For example, the
supporting member is formed separately from the panel-shaped component
14
14
and bonded to the panel body. Alternatively, the supporting member may be
formed integrally with the panel-shaped component by pressing. There are
no limits to the material of the supporting member. When the supporting
member is formed separately from the panel-shaped component, the
supporting member is, for example, made of plastic. Alternatively, the
supporting member may be made of metal. In this case, the metal is steel,
for example. The way of bonding the supporting member to the panel body
is adhesive bonding, for example. The way of bonding may be welding or
mechanical fastening. For example, when the panel-shaped component is a
door outer panel and when the supporting member is formed integrally with
the panel-shaped component, the supporting member may be a character line
formed on the panel body.
[0049]
In the stiffened panel structure with the fifth configuration, a wire as
used in the stiffened panel structure with the first configuration is usable as
the wire.
[0050]
In the stiffened panel structure with the fifth configuration, the
second point is opposed to the first point with the supporting member in
between. In other words, the supporting member is located between the first
point and the second point. The first end portion of the wire is bonded to the
first point of the panel body, and the second end portion of the wire is bonded
to the second point of the panel body. Thus, the wire is bonded to the panel
body at the first end portion and the second end portion. Then, the wire is
strained between the first point and the second point via the supporting
member.
[0051]
In the stiffened panel structure with the fifth configuration, the wire
is strained between the first point and the second point via the supporting
member. The first point and the second point are respectively in separate
outward deformation areas. In this case, as in the stiffened panel structure
with the first configuration, the wire is subjected to tensile force when a load
is applied to the expected load point. Therefore, the flare rigidity of the
panel-shaped component is enhanced.
[0052]
15
15
In the stiffened panel structure with the fifth configuration, the
junction area between the panel body and the wire is small, as in the stiffened
panel structure with the first configuration. Therefore, the surface quality
of the panel-shaped component can be maintained.
[0053]
The stiffened panel structure with the fifth configuration is preferably
configured as follows. The panel body includes an expected load point onto
which a load is expected to be applied from outside, a first area, and a second
area. Without the wire, the first area and the second area are expected to be
displaced in directions opposite to a loading direction and away from the
expected load point when a load is applied to the expected load point from
outside. The second point is opposed to the first point with the expected load
point in between. The first point is in the first area, and the second point is
in the second area. The supporting member is positioned between the first
area and the second area. (This configuration will be referred to as sixth
configuration.)
[0054]
In the stiffened panel structure with the sixth configuration, the first
area and the second area correspond to the outward deformation areas
described above. In this case, the surface quality of the panel-shaped
component can be maintained more certainly, and the flare rigidity of the
panel-shaped component can be enhanced more.
[0055]
In the stiffened panel structure with any one of the first to sixth
configurations, the panel-shaped component is preferably made of metal.
(This configuration will be referred to as seventh configuration.) In the
seventh configuration, the panel-shaped component is preferably made of
steel. (This configuration will be referred to as eighth configuration.)
However, the metal is not limited to steel. For example, the metal may be
aluminum or magnesium.
[0056]
In the stiffened panel structure with any one of the first to eighth
configurations, the wire is preferably made of metal. (This configuration will
be referred to as ninth configuration.) In the ninth configuration, the wire
is preferably made of steel. (This configuration will be referred to as tenth
16
16
configuration.)
[0057]
In the stiffened panel structure with any one of the seventh to tenth
configurations, the panel-shaped component and the wire are made of a same
kind of material. (This configuration will be referred to as eleventh
configuration.) In the stiffened panel structure with the eleventh
configuration, the coefficient of linear expansion of the wire is the same as the
coefficient of linear expansion of the panel body. Accordingly, the coefficient
of linear expansion of the wire does not affect the shape of the panel body.
Therefore, the surface quality of the panel-shaped component can be
maintained more certainly.
[0058]
In the stiffened panel structure with any one of the first to seventh
configurations, the wire is a CFRP wire. (This configuration will be referred
to as twelfth configuration.) The wire preferably has a high Young's modulus.
The high Young's modulus of the wire increases the effect to enhance the flare
rigidity.
[0059]
In the stiffened panel structure with any one of the first to twelfth
configurations, the panel-shaped component is preferably an outer panel for
an automobile. (This configuration will be referred to as thirteenth
configuration.) In the thirteenth configuration, the panel-shaped component,
which is an outer panel, is a door outer panel, a hood, a roof or a fender, for
example.
[0060]
In any of the above-described stiffened panel structures, the way of
bonding the first end portion of the wire to the panel body and the way of
bonding the second end portion of the wire to the panel body or the auxiliary
component are preferably adhesive bonding. This is because adhesive
bonding does not affect the appearance of the panel body. However, the way
of bonding may be welding or mechanical fastening.
[0061]
When a heat treatment (for example, baking finishing) is applied to
the panel-shaped component, the bonding between the panel body and the
wire may be carried out before the heat treatment or after the heat treatment.
17
17
However, when the wire is a CFPR wire, in view of the difference in thermal
expansion, it is preferred that the bonding between the panel body and the
wire is carried out after the heat treatment.
[0062]
With reference to the drawings, stiffened panel structures according
to some embodiments of the present disclosure will be described with some
specific examples. The parts that are the same or correspond to each other
are provided with the same reference signs, and descriptions of those parts
will not be repeated.
[0063]
[First Embodiment]
With reference to FIGS. 1 to 5, a stiffened panel structure 1, in which
a panel-shaped component 2 is stiffened, according to a first embodiment will
be described. In the stiffened panel structure 1, the panel-shaped
component 2 is an outer panel for an automobile. The outer panel may be a
door outer panel, a hood, a roof, a fender, or the like. In the present
specification, in order to indicate the directions of the stiffened panel
structure 1 with the panel-shaped component 2, X direction, Y direction and
Z direction that are orthogonal to one another will be used in some cases. In
planar view of the panel-shaped component 2, X direction and Y direction are
directions in which the panel-shaped component 2 is stretched. Z direction
is a direction perpendicular to the directions in which the panel-shaped
component 2 is stretched, and the outside O and inside I of the panel-shaped
component 2 are defined with respect to Z direction.
[0064]
FIGS. 1 and 2 are diagrams showing the stiffened panel structure 1,
in which the panel-shaped component 2 is stiffened, according to the first
embodiment. FIG. 1 is a sectional view of the stiffened panel structure 1
when the panel-shaped component 2 is cut in a plane perpendicular to X
direction. FIG. 2 is a plan view of the stiffened panel structure 1 when the
panel-shaped component 2 shown in FIG. 1 is viewed from inside I.
[0065]
As shown in FIGS. 1 and 2, the stiffened panel structure 1 includes a
panel-shaped component 2 and one or more wires 3. In the present
embodiment, the number of wires 3 is three. However, the number of wires
18
18
3 is not limited to three, and the number of wires 3 may be one, two, three or
more.
[0066]
(Panel-Shaped Component 2)
In the present embodiment, the panel-shaped component 2 is
rectangular in planar view from Z direction. The panel-shaped component 2
includes a panel body 21. The panel-shaped component 2 has a first lateral
edge 22A at one end of the panel body 21 in Y direction. The panel-shaped
component 2 has a second lateral edge 22B at the other end of the panel body
21 in Y direction.
[0067]
The panel-shaped component 2 is formed from a metal sheet.
Specifically, the panel-shaped component 2 is formed from a steel sheet. The
center portion of the panel body 21 with respect to Y direction is formed into
a curved surface projecting outward O. Thus, the panel body 21 curves in
such a manner as to be convex outward O. The cross-sectional shape of the
panel body 21 is like a circular arc. However, the cross-sectional shape of
the panel body 21 needs to be only a convex curve projecting outward O and
may be shaped like an elliptic arc or any other convex curve. The crosssection
of the panel body 21 shown in FIG. 1 is drawn with some exaggeration.
In the other drawings also, some exaggeration is included.
[0068]
(Wires 3)
The wires 3 are made of metal, that is, are metal wires. Specifically,
the wires 3 are made of steel, that is, are steel wires. Each of the wires 3 is
a single wire that is a single wire rod. However, each of the wires 3 may be
a twisted wire of a plurality of wire rods. Each of the wires 3 is a slender
linear member. For example, each of the wires 3 has a diameter of 2.0 mm.
It is preferred that each of the wires 3 has a diameter within the range of 0.3
to 3.0 mm.
[0069]
Each of the wires 3 extends in Y direction of the panel body 21.
Specifically, each of the wires 3 lies in the range of the circular arc drawn by
the cross-section of the panel body 21 and extends in Y direction from the first
lateral edge 22A toward the second lateral edge 22B. The three wires 3 are
19
19
arranged side by side in X direction in an equidistant manner (see FIG 2).
[0070]
Each of the wires 3 has a first end portion 31 and a second end portion
32. Among opposite end portions of the wire 3, one end portion is the first
end portion 31, and the other end portion is the second end portion 32. The
first end portion 31 is bonded to a first point 211 on the inner surface 21a of
the panel body 21 by an adhesive 4. The second end portion 32 is bonded to
a second point 212 on the inner surface 21a of the panel body 21 by the
adhesive 4. The first point 211 is away from the second point 212 in Y
direction of the panel body 21.
[0071]
FIG. 3 is a diagram showing the way of attaching each wire 3 to the
panel body 21 in the stiffened panel structure 1 according to the present
embodiment. The upper section of FIG. 3 shows a state before bonding, and
the lower section of FIG. 3 shows a state after bonding. FIG. 3 shows the
second end portion 32 of the wire 3 as an example.
[0072]
As shown in the upper section of FIG. 3, for the attachment of each of
the wires 3 to the panel body 21, the wire 3 is bent at the respective bases 33
of the first end portion 31 and the second end portion 32. Each of the bases
33 is brought into contact with the inner surface 21a of the panel body 21.
Then, as shown in the lower section of FIG. 3, the wire 3 is turned around the
axis of the wire body 34 in the direction shown by arrow. Thereby, the first
end portion 31 and the second end portion 32 of the wire 3 are stuck to the
inner surface 21a of the panel body 21.
[0073]
In this state, the adhesive 4 is supplied to the first end portion 31 and
the second end portion 32 of the wire 3. The first end portion 31 and the
second end portion 32 of the wire 3 are fixed by the hardened adhesive 4. In
this way, the first end portion 31 and the second end portion 32 are bonded to
the panel body 21.
[0074]
The way of attaching the wires 3 to the panel body 21 is not limited to
the way of attaching shown in FIG. 3. In order to enhance the junction
strength, for example, each of the first end portion 31 and the second end
20
20
portion 32 may be formed into a swirl preliminarily. When an adhesive is
used for the bonding, any imprints of bonding that degrade appearance do not
appear on the outer surface 21b of the panel body 21. In terms of appearance,
it is preferred that an adhesive is used for the bonding. However, when the
outer surface 21b of the panel body 21 is finally covered with another member,
welding or mechanical fastening may be adopted as the way of bonding
because it is not necessary to worry about the appearance of the panel body
21.
[0075]
When a heating treatment (for example, baking finishing) is applied
to the panel-shaped component 2, it does not matter whether the wires 3 are
bonded to the panel body 21 before the heat treatment or after the heat
treatment.
[0076]
As shown in FIG. 1, the first end portion 31 of each of the wires 3 is
bonded to the first point 211, and the second end portion 32 of each of the
wires 3 is bonded to the second point 212. Thus, each of the wires 3 is bonded
to the panel body 21 at the first end portion 31 and the second end portion 32.
Then, each of the wires 3 is strained between the first point 211 and the
second point 212.
[0077]
In this case, the wire body 34 of each of the wires 3 extends on an
imaginary line L passing through the first point 211 and the second point 212.
Thus, each of the wires 3 extends linearly between the first point 211 and the
second point 212. The wire body 34 extending between the first point 211
and the second point 212 is out of contact with the inner surface 21a of the
panel body 21. There is a space S between the wire body 34 and the panel
body 21.
[0078]
FIGS. 4A to 4C are diagrams showing deformation behaviors that the
panel body 21 without the wires 3 attached thereto is expected to exhibit
when a load F is applied to the panel-shaped component 2 from outside O.
FIGS. 4A and 4B are perspective views of the panel-shaped component 2.
FIG. 4C is a sectional view of the panel-shaped component 2 when the panelshaped
component 2 is cut in a plane perpendicular to X direction. These
21
21
figures show results (simulation models and values) of CAE (Computer Aided
Engineering) analysis.
[0079]
Regarding the panel-shaped component 2 shown in FIGS. 4A to 4C,
the center C of the panel body 21 with respect to X direction and Y direction
projects most outward O. The stiffened panel structure 1 according to the
first embodiment is expected to be subjected to a load F applied to the center
C of the panel body 21 from the outer surface 21b toward the inner surface
21a of the panel body 21. Thus, the center C of the panel body 21 is an
expected load point as described above. When the load F is applied to the
center C (expected load point) of the panel body 21 from outside O, the panel
body 21 bends. The CAE analysis was conducted with the load F set to two
values, 10N and 25N.
[0080]
FIGS. 4A and 4B show that areas A1 and A2 were deformed outward
O when a load F was applied to the center C (expected load point) of the panel
body 21. The areas A1 and A2 were displaced along Z direction. In other
words, the areas A1 and A2 were displaced in the opposite direction to the
direction of load F. Further, the areas A1 and A2 were displaced along Y
direction. In other words, the areas A1 and A2 were displaced in directions
away from the center C.
[0081]
FIG. 4C shows the amounts of displacements of various points of the
panel body 21, and the amounts shown in FIG. 4C were magnified a hundred
times the values obtained as the analysis results. In FIG. 4C, the solid line
shows the state before the application of load F. The alternate long and dash
line shows the state when a load F of 10 N was applied. The alternate long
and two short dashes line shows the state when a load F of 25 N was applied.
[0082]
As shown in FIG. 4C, when a load F is applied to the center C
(expected load point) of the panel body 21 from outside O, the center C is
displaced in the direction of load F. In other words, the center C is displaced
toward the inside I of the panel body 21.
[0083]
With the displacement of the center C, the areas A1 and A2, which are
22
22
away from the center C in Y direction, are deformed toward the outside O of
the panel body 21. Thus, the areas A1 and A2 are displaced in a direction
that is opposite to the direction of load F and away from the center C.
Therefore, the areas A1 and A2 are outward deformation areas as described
above. The area A1 is near the first lateral edge 22A of the panel-shaped
component 2. The area A2 is near the second lateral edge 22B of the panelshaped
component 2. In a sectional view of the panel-shaped component 2,
the areas A1 and A2 are on both sides of the center C. In other words, the
area A2 lies on the side opposite to the area A1 with the center C (expected
load point) in between. As shown in FIGS. 4A to 4C, the ranges of the areas
A1 and A2 when the load F was 25N were larger than the ranges of the areas
A1 and A2 when the load F was 10N.
[0084]
The areas A1 and A2 determined by the CAE analysis indicate
outward deformation areas. Without the wires 3, when a load F is applied
to the center C (expected load point) of the panel-shaped component 2 from
outside O, the outward deformation areas are displaced in directions that are
opposite to the direction of load F and away from the center C. In this
specification, the area A1, which is an outward deformation area near the
first lateral edge 22A of the panel body 21, will be referred to as first area A1
in some cases. The area A2, which is an outward deformation area near the
second lateral edge 22B of the panel body 21, will be referred to as second
area A2 in some cases.
[0085]
As shown in FIG. 4C, the amounts of lateral displacements
(displacements in Y direction) of the first area A1 and the second area A2 due
to the application of load F of 25 N were greater than those due to the
application of load F of 10 N. The first area A1 near the first lateral edge
22A of the panel-shaped component 2 is displaced in a first deformation
direction D1 toward the first lateral edge 22A. At the same time, the second
area A2 near the second lateral edge 22B of the panel-shaped component 2 is
displaced in a second deformation direction D2 toward the second lateral edge
22B. Thus, the first area A1 and the second area A2 are displaced in
directions away from the center C (expected load point) of the panel body 21
with respect to Y direction.
23
23
[0086]
As shown in FIG. 1, the respective first end portions 31 of the wires 3
are bonded to first points 211 of the panel body 21, and the respective second
end portions 32 of the wires 3 are bonded to second points 212 of the panel
body 21. The first points 211 are in the first area A1, and the second points
212 are in the second area A2. Accordingly, the first points 211 to which the
respective first end portions 31 of the wires 3 are bonded and the second
points 212 to which the respective second end portions 32 are bonded are in
outward deformation areas.
[0087]
Each of the wires 3 extends linearly in Y direction between the first
point 211 (in the first area A1) and the second point 212 (in the second area
A2).
[0088]
In the present embodiment, the first area A1 and the second area A2,
which are outward deformation areas, are determined from a CAE analysis.
However, the way to determine outward deformation areas is not limited to a
CAE analysis. For example, a panel-shaped component 2 without any wires
3 attached thereto may be subjected to a test in which a load F is applied
thereto, and outward deformation areas may be determined based on the test
results.
[0089]
(Function and Effect)
The function and the effect of the stiffened panel structure 1 will be
described below.
[0090]
The respective first end portions 31 of the wires 3 are bonded to first
points 211 of the panel body 21, and the respective second end portions 32 of
the wires 3 are bonded to second points 212 of the panel body 21. The first
points 211 and the second points 212 are in outward deformation areas (first
area A1 and second area A2), respectively, which are away from each other.
Then, each of the wires 3 is strained between the first point 211 and the
second point 212. Each of the wires 3 extends linearly in Y direction along
an imaginary line L.
[0091]
24
24
FIG. 5 is a diagram showing a stiffened panel structure 1 according to
the present embodiment in a state in which a load F is applied to the panelshaped
component 2 from outside O. The left side of FIG. 5A is a crosssectional
view of the panel-shaped component 2, and the right side of FIG. 5
is an enlarged view showing the point on which the load F is applied and a
part around it.
[0092]
As shown in FIG. 5, when a load F is applied to the panel body 21, the
panel body 21 bends. In this case, the first area A1 and the second area A2
of the panel body 21 are deformed outward, and with the deformation, the
wires 3 are subjected to tensile force T. At the same time, the panel body 21
receives, from the wires 3, reaction force to the tensile force T on the first
points 211 and the second points 212. This suppresses deformation of the
panel body 21 at the first points 211 and the second points 212. The
suppression of deformation of the panel body 21 at the first points 211 and
the second points 212 makes it possible to suppress deformation of the first
area A1 and the second area A2 of the panel body 21. Thus, deformation of
the outward deformation areas can be suppressed. Then, deformation of the
expected load point of the panel body 21 due to a load F applied thereto can
be suppressed. Accordingly, the flare rigidity of the panel-shaped component
2 can be enhanced. Hence, the wires 3 function as reinforcing members.
[0093]
The wire bodies 34 extending between the respective first points 211
and the respective second points 212 are out of contact with the inner surface
21a of the panel body 21. In other words, each of the wires 3, which functions
as a reinforcing member, is bonded to the panel body 21 only at its first end
portion 31 and its second end portion 32. Accordingly, the junction area
between the panel body 21 and each of the wires 3 is small.
[0094]
Therefore, as compared with a conventional stiffened panel structure
in which a reinforcing member is entirely stuck to the panel body 21, even if
the dimensional accuracy of each of the wires 3 (reinforcing member) is not
strictly managed, the shapes of the wires 3 do not have so large an effect on
the panel body 21. When the panel-shaped component 2 and the wires 3 are
subjected to a heat treatment (e.g., baking finishing), the coefficient of linear
25
25
expansion of the wires 3 do not have so large an effect on the shape of the
panel body 21, regardless of whether the material of the wires 3 and the
material of the panel-shaped component 2 are of the same kind or different
kinds. Thus, the surface quality of the panel-shaped component 2 can be
maintained.
[0095]
In the present embodiment, the panel-shaped component 2 is made of
metal (specifically, steel), and the wires 3 are made of metal (specifically,
steel). Thus, the panel-shaped component 2 is made of the same kind of
material as the wires 3 that are bonded to the panel body 21 of the panelshaped
component 2. In this case, the coefficient of linear expansion of the
wires 3 is the same as the coefficient of linear expansion of the panel body 21.
Therefore, the coefficient of linear expansion of the wires 3 has no effect on
the shape of the panel body 21. Accordingly, the surface quality of the panelshaped
component 2 can be maintained more certainly.
[0096]
As described above, in the stiffened panel structure 1 according to the
present embodiment, the surface quality of the panel-shaped component 2 can
be maintained, and the flare rigidity of the panel-shaped component 2 can be
enhanced.
[0097]
In the present embodiment, the panel body 21 curves in such a
manner as to be convex outward O. Thus, the panel body 21 does not curve
in such a manner as to be concave to the outside O. For effective use of the
present embodiment, in a sectional view of the panel body 21, the radius of
curvature R of the convex curve is preferably 100 mm or more.
[0098]
Japanese Patent Application Publication No. 2008-68757 discloses a
method of enhancing flare rigidity by attaching a tensile force applying jig
inside of a door outer panel.
[0099]
According to this method of enhancing flare rigidity, a tensile force
applying jig is set in a door outer panel, the coefficient of linear expansion of
the tensile force applying jig being higher than that of the door outer panel,
and the panel is thermally distorted during a painting process and thereby
26
26
plastically deformed. In this way, the rigidity of the door outer panel after
detachment of the tensile force applying jig is improved.
[0100]
Thus, according to this method of enhancing flare rigidity, after the
painting process, the tensile force applying jig is detached from the door outer
panel. Accordingly, it never happens that the door outer panel is subjected
to a load while the tensile force applying jig is attached thereto.
[0101]
Since the method of enhancing flare rigidity has a step of detaching
the tensile force applying jig after the painting process, the way of attaching
the tensile force applying jig is a set-in method. Therefore, if the door outer
panel is subjected to a load while the tensile force applying jig is attached
thereto, a gap will be made in the set-in portion, and the tensile force applying
jig will come out.
[0102]
On the other hand, in the stiffened panel structure 1 of the present
embodiment, the respective first end portions 31 and the respective second
end portions 32 of the wires 3 are bonded to the panel body 21. Accordingly,
the wires 3 enhance the flare rigidity of the panel-shaped component 2.
[0103]
[Second Embodiment]
FIG. 6 shows a stiffened panel structure 1A, in which a panel-shaped
component 2 is stiffened, according to a second embodiment. FIG. 6 is a plan
view of the stiffened panel structure 1A when the panel-shaped component 2
is viewed form inside I. The stiffened panel structure 1A of the second
embodiment is a modification of the stiffened panel structure 1 of the first
embodiment. The second embodiment will hereinafter be described mainly
with respect to differences from the first embodiment.
[0104]
In the stiffened panel structure 1A of the present embodiment, the
panel-shaped component 2 is rectangular in planar view from Z direction.
Along the four sides of the panel-shaped component 2, which define the
outline of the panel-shaped component 2, beads 26 are formed. The beads
26 are formed outside the panel body 21.
[0105]
27
27
In the same way as in the first embodiment, wires 3 are attached to
the panel body 21. In the present embodiment, however, the number of wires
3 is five. These five wires 3 are arranged side by side in X direction in an
equidistant manner. The panel-shaped component 2 is stiffened by these
five wires 3. In this case, as compared with the stiffened panel structure of
the first embodiment, the flare rigidity of the panel-shaped component 2
becomes higher with the increase in the number of wires 3.
[0106]
[Third Embodiment]
FIG. 7 shows a stiffened panel structure 1B, in which a panel-shaped
component 2 is stiffened, according to a third embodiment. FIG. 7 is a plan
view of the stiffened panel structure 1B when the panel-shaped component 2
is viewed from inside I. The stiffened panel structure 1B of the third
embodiment is a modification of the stiffened panel structure 1A of the second
embodiment. The third embodiment will hereinafter be described mainly
with respect to differences from the second embodiment.

We claim:
1. A stiffened panel structure comprising:
a panel-shaped component including a panel body that curves in such
a manner as to be convex outward; and
a wire having a first end portion and a second end portion, the first
end portion being bonded to a first point on an inner surface of the panel body
and the second end portion being bonded to a second point on the inner
surface of the panel body in such a manner that the wire is strained between
the first point and the second point.
2. The stiffened panel structure according to claim 1,
wherein:
the panel body includes:
an expected load point onto which a load is expected to be
applied from outside; and
a first area and a second area that, without the wire, are
expected to be displaced in directions opposite to a loading direction and away
from the expected load point when a load is applied to the expected load point
from outside;
the second area is opposed to the first area with the expected load
point in between; and
the first point is in the first area, and the second point is in the second
area.
3. A stiffened panel structure comprising:
a panel-shaped component including a panel body that is flat or curves
in such a manner as to be convex outward;
an auxiliary component that is positioned inside the panel-shaped
component and integrated with the panel-shaped component; and
a wire having a first end portion and a second end portion, the first
end portion being bonded to a first point on an inner surface of the panel body
and the second end portion being bonded to the auxiliary component in such
a manner that the wire is strained between the first point and the auxiliary
component.
56
56
4. The stiffened panel structure according to claim 3,
wherein:
the panel body includes:
an expected load point onto which a load is expected to be
applied from outside; and
a first area that, without the wire, is expected to be displaced
in a direction opposite to a loading direction and away from the expected load
point when a load is applied to the expected load point from outside and
the first point is in the first area.
5. A stiffened panel structure comprising:
a panel-shaped component including a panel body that is flat or curves
in such a manner as to be convex outward;
a supporting member projecting from an inner surface of the panel
body; and
a wire having a first end portion and a second end portion, the first
end portion being bonded to a first point on the inner surface of the panel
body and the second end portion being bonded to a second point on the inner
surface of the panel body, the second point being opposed to the first point
with the supporting member in between, in such a manner that the wire is
strained between the first point and the second point via the supporting
member.
6. The stiffened panel structure according to claim 5,
wherein:
the panel body includes:
an expected load point onto which a load is expected to be
applied from outside; and
a first area and a second area that, without the wire, are
expected to be displaced in directions opposite to a loading direction and away
from the expected load point when a load is applied to the expected load point
from outside;
the second area is opposed to the first area with the expected load
point in between;
57
57
the first point is in the first area, and the second point is in the second
area; and
the supporting member is positioned between the first area and the
second area.
7. The stiffened panel structure according to any one of claims 1 to 6,
wherein the panel-shaped component is made of metal.
8. The stiffened panel structure according to claim 7,
wherein the panel-shaped component is made of steel.
9. The stiffened panel structure according to any one of claims 1 to 8,
wherein the wire is made of metal.
10. The stiffened panel structure according to claim 9,
wherein the wire is made of steel.
11. The stiffened panel structure according to any one of claims 7 to 10,
wherein the panel-shaped component and the wire are made of a same
kind of material.
12. The stiffened panel structure according to any one of claims 1 to 7,
wherein the wire is a CFRP wire.
13. The stiffened panel structure according to any one of claims 1 to 12,
wherein the panel-shaped component is an outer panel for an
automobile.