U.S. patent application number 16/498056 was filed with the patent office on 2020-04-02 for underfloor double skin structure, vehicle underfloor structure, and vehicle.
The applicant listed for this patent is Mitsubishi Heavy Industries Engineering, Ltd.. Invention is credited to Ichiro JOREN, Yoshinori KATO, Hiroyuki KONO, Koshi TANIMOTO.
Application Number | 20200101988 16/498056 |
Document ID | / |
Family ID | 63677784 |
Filed Date | 2020-04-02 |
United States Patent
Application |
20200101988 |
Kind Code |
A1 |
TANIMOTO; Koshi ; et
al. |
April 2, 2020 |
UNDERFLOOR DOUBLE SKIN STRUCTURE, VEHICLE UNDERFLOOR STRUCTURE, AND
VEHICLE
Abstract
An underfloor double skin structure includes a first upper plate
including a pair of first thin portions disposed on both end
portions thereof and a first thick portion disposed inwardly with
respect to the pair of first thin portions, a first lower plate
disposed to be spaced apart downward of the first upper plate and
including a pair of second thin portions disposed on both end
portions thereof and a second thick portion disposed inwardly with
respect to the pair of second thin portions, a first rib group
integrally formed with the first upper plate and the first lower
plate and connects the first upper plate and the first lower plate,
a reinforcing body is formed of the first thick portion, the second
thick portion, and a pair of thick ribs, and the second thick
portion is disposed downward of the pair of second thin
portions.
Inventors: |
TANIMOTO; Koshi; (Tokyo,
JP) ; JOREN; Ichiro; (Tokyo, JP) ; KONO;
Hiroyuki; (Tokyo, JP) ; KATO; Yoshinori;
(Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Mitsubishi Heavy Industries Engineering, Ltd. |
Kanagawa |
|
JP |
|
|
Family ID: |
63677784 |
Appl. No.: |
16/498056 |
Filed: |
March 30, 2018 |
PCT Filed: |
March 30, 2018 |
PCT NO: |
PCT/JP2018/013676 |
371 Date: |
September 26, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B61F 1/12 20130101; B61D
17/10 20130101; B61F 1/00 20130101; B61D 17/041 20130101 |
International
Class: |
B61F 1/12 20060101
B61F001/12; B61D 17/10 20060101 B61D017/10; B61D 17/04 20060101
B61D017/04 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 31, 2017 |
JP |
2017-069448 |
Claims
1. An underfloor double skin structure configuring an underfloor
for a vehicle, comprising: a first upper plate that extends in a
forward and rearward direction of the vehicle; a first lower plate
that extends in the forward and rearward direction of the vehicle,
the first lower plate being disposed to be spaced apart downward of
the first upper plate; and a first rib group that includes a
plurality of ribs, the plurality of ribs being integrally formed
with the first upper plate and the first lower plate, the plurality
of ribs being provided between the first upper plate and the first
lower plate, and the plurality of ribs being configured to connect
the first upper plate and the first lower plate with each other,
wherein the first upper plate includes a pair of first thin
portions and a first thick portion thicker than each of the pair of
first thin portions, the pair of first thin portions configuring
both end portions of the first upper plate in a width direction of
the vehicle, the first lower plate includes a pair of second thin
portions and a second thick portion thicker than each of the pair
of second thin portions, the pair of second thin portions
configuring the end portions of the first lower plate in the width
direction of the vehicle, the first rib group includes a pair of
thick ribs which are disposed to be spaced apart from each other in
the width direction of the vehicle, the pair of thick ribs being
configured to connect the first thick portion and the second thick
portion to each other, and each of the pair of thick ribs being
thicker than each of the first thin portion and the second thin
portion, a reinforcing body is formed by the first thick portion,
the second thick portion, and the pair of thick ribs, and the
second thick portion is disposed downward of the pair of second
thin portions.
2. The underfloor double skin structure according to claim 1,
wherein the reinforcing body partitions a plane perpendicular to
the forward and rearward direction of the vehicle to be a closed
space.
3. The underfloor double skin structure according to claim 1,
wherein the second thick portion and the pair of second thin
portions are disposed adjacent to each other in a horizontal
direction, and the second thick portion and the pair of second thin
portions are integrally formed in the width direction of the
vehicle.
4. The underfloor double skin structure according to claim 1,
wherein the pair of thick ribs extend downward of the pair of
second thin portions.
5. The underfloor double skin structure according to claim 1,
wherein the pair of thick ribs connect the first thick portion and
the second thick portion to each other in a vertical direction.
6. The underfloor double skin structure according to claim 5,
wherein the first rib group includes a pair of inclined ribs that
connect the first thick portion and the second thick portion to
each other, and the pair of inclined ribs are inclined in a
direction in which a distance between the pair of inclined ribs
increases from the second thick portion toward the first thick
portion.
7. The underfloor double skin structure according to claim 1,
wherein the first thick portion and the second thick portion are
flat plates, and the reinforcing body is bilaterally symmetrical
with respect to a first plane which passes through a center
position of the reinforcing body, the first plane being
perpendicular to the first thick portion and the second thick
portion, and the first plane being parallel with the forward and
rearward direction of the vehicle.
8. The underfloor double skin structure according to claim 1,
wherein the first thick portion and the second thick portion are
flat plates, and a structure including at least the first thick
portion, the second thick portion, and the pair of thick ribs in
the reinforcing body is vertically symmetrical with respect to a
second plane which passes through an intermediate position between
the first thick portion and the second thick portion while being
parallel with the first thick portion and the second thick
portion.
9. The underfloor double skin structure according to claim 3,
wherein the first thick portion and the pair of first thin portions
are disposed adjacent to one another in the horizontal direction,
and the first thick portion and the pair of first thin portions are
integrally formed in the width direction of the vehicle, and a
structure including the pair of first thin portions, the pair of
second thin portions, the first thick portion, the second thick
portion, and the pair of thick ribs are vertically symmetrical with
respect to a second plane which passes through an intermediate
position between the first thick portion and the second thick
portion while being parallel with the first thick portion and the
second thick portion.
10. A vehicle underfloor structure comprising: the underfloor
double skin structure according to claim 1; and another double skin
structure provided in a position adjacent to the underfloor double
skin structure in the width direction of the vehicle; wherein the
other double skin structure comprises: a second upper plate that
extends in the forward and rearward direction of the vehicle; a
second lower plate that is disposed to be spaced apart downward of
the second upper plate and extends in the forward and rearward
direction of the vehicle; and a second rib group that is integrally
formed with the second upper plate and the second lower plate, is
provided between the second upper plate and the second lower plate,
and connects the second upper plate and the second lower plate to
each other, wherein an end of the second upper plate is connected
to an end of the first upper plate, and an end of the second lower
plate is connected to an end of the first lower plate.
11. A vehicle comprising: the vehicle underfloor structure
according to claim 10.
12. (canceled)
13. An underfloor double skin structure configuring an underfloor
for a vehicle, comprising: a first upper plate that extends in a
forward and rearward direction of the vehicle; a first lower plate
that extends in the forward and rearward direction of the vehicle,
the first lower plate being disposed to be spaced apart downward of
the first upper plate; and a first rib group that includes a
plurality of ribs, the plurality of ribs being integrally formed
with the first upper plate and the first lower plate, the plurality
of ribs being provided between the first upper plate and the first
lower plate, and the plurality of ribs being configured to connect
the first upper plate and the first lower plate with each other,
wherein the first upper plate includes a pair of first thin
portions and a first thick portion thicker than each of the pair of
first thin portions, the pair of first thin portions configuring
both end portions of the first upper plate in a width direction of
the vehicle, the first lower plate includes a pair of second thin
portions and a second thick portion thicker than each of the pair
of second thin portions, the pair of second thin portions
configuring the end portions of the first lower plate in the width
direction of the vehicle, the first rib group includes a pair of
thick ribs which are disposed to be spaced apart from each other in
the width direction of the vehicle, the pair of thick ribs being
configured to connect the first thick portion and the second thick
portion to each other, and each of the pair of thick ribs being
thicker than each of the first thin portion and the second thin
portion, a reinforcing body is formed by the first thick portion,
the second thick portion, and the pair of thick ribs, and the
reinforcing body partitions a plane perpendicular to the forward
and rearward direction of the vehicle to be a closed space.
14. The underfloor double skin structure according to claim 13,
wherein the second thick portion and the pair of second thin
portions are disposed adjacent to each other in a horizontal
direction, and the second thick portion and the pair of second thin
portions are integrally formed in the width direction of the
vehicle.
15. The underfloor double skin structure according to claim 13,
wherein the pair of thick ribs extend downward of the pair of
second thin portions, and the second thick portion is disposed
downward of the pair of second thin portions.
16. The underfloor double skin structure according to claim 13,
wherein the pair of thick ribs connect the first thick portion and
the second thick portion to each other in a vertical direction.
17. The underfloor double skin structure according to claim 16,
wherein the first rib group includes a pair of inclined ribs that
connect the first thick portion and the second thick portion to
each other, and the pair of inclined ribs are inclined in a
direction in which a distance between the pair of inclined ribs
increases from the second thick portion toward the first thick
portion.
18. The underfloor double skin structure according to claim 13,
wherein the first thick portion and the second thick portion are
flat plates, and the reinforcing body is bilaterally symmetrical
with respect to a first plane which passes through a center
position of the reinforcing body, the first plane being
perpendicular to the first thick portion and the second thick
portion, and the first plane being parallel with the forward and
rearward direction of the vehicle.
19. The underfloor double skin structure according to claim 13,
wherein the first thick portion and the second thick portion are
flat plates, and a structure including at least the first thick
portion, the second thick portion, and the pair of thick ribs in
the reinforcing body is vertically symmetrical with respect to a
second plane which passes through an intermediate position between
the first thick portion and the second thick portion while being
parallel with the first thick portion and the second thick
portion.
20. The underfloor double skin structure according to claim 14,
wherein the first thick portion and the pair of first thin portions
are disposed adjacent to one another in the horizontal direction,
and the first thick portion and the pair of first thin portions are
integrally formed in the width direction of the vehicle, and a
structure including the pair of first thin portions, the pair of
second thin portions, the first thick portion, the second thick
portion, and the pair of thick ribs are vertically symmetrical with
respect to a second plane which passes through an intermediate
position between the first thick portion and the second thick
portion while being parallel with the first thick portion and the
second thick portion.
21. A vehicle underfloor structure comprising: the underfloor
double skin structure according to claim 13; and another double
skin structure provided in a position adjacent to the underfloor
double skin structure in the width direction of the vehicle;
wherein the other double skin structure comprises: a second upper
plate that extends in the forward and rearward direction of the
vehicle; a second lower plate that is disposed to be spaced apart
downward of the second upper plate and extends in the forward and
rearward direction of the vehicle; and a second rib group that is
integrally formed with the second upper plate and the second lower
plate, is provided between the second upper plate and the second
lower plate, and connects the second upper plate and the second
lower plate to each other, wherein an end of the second upper plate
is connected to an end of the first upper plate, and an end of the
second lower plate is connected to an end of the first lower plate.
Description
RELATED APPLICATIONS
[0001] The present application is a National Phase of International
Application Number PCT/JP2018/013676 filed Mar. 30, 2018 and claims
priority to Japanese Application Number 2017-069448 filed Mar. 31,
2017.
TECHNICAL FIELD
[0002] The present invention relates to an underfloor double skin
structure, a vehicle underfloor structure, and a vehicle.
[0003] Priority is claimed on Japanese Patent Application No.
2017-069448, filed on Mar. 31, 2017, the content of which is
incorporated herein by reference.
BACKGROUND ART
[0004] A double skin structure being excellent in a weight
reduction is applied as a vehicle body of a railway vehicle (see,
for example, Patent Document 1) which is one of vehicles.
[0005] The double skin structure has an upper plate and a lower
plate, and a plurality of ribs. The upper plate and the lower plate
are disposed in a state of being separated from each other in an
upward and downward direction of the vehicle. The plurality of ribs
are disposed between the upper plate and the lower plate, and
connect the upper plate and the lower plate to each other. The
upper plate, the lower plate, and the plurality of ribs are thin
plates. The double skin structure having such configuration is
manufactured using an extrusion forming method.
[0006] In a case where a vehicle underfloor structure is formed
using the double skin structure, a plurality of the double skin
structures extending in a forward and rearward direction of the
vehicle are disposed in a width direction of the vehicle, and the
adjacent double skin structures are joined together. Specifically,
for example, the upper plates are joined together, and the lower
plates are joined together.
[0007] As described above, the double skin structure is formed of
the thin plates. Therefore, in the double skin structure,
positioning end portions (joining positions) of the adjacent double
skin structures can be easily performed.
[0008] On the other hand, since the double skin structure is formed
of the thin plates, a strength of the double skin structure is low.
In order to improve the strength of the vehicle underfloor
structure, separately preparing a middle beam extending in the
forward and rearward direction of the vehicle and welding the
middle beam to a lower surface side of the double skin structure of
the vehicle underfloor structure are performed.
CITATION LIST
Patent Literature
[0009] [Patent Document 1] Japanese Patent No. 3625779
SUMMARY OF INVENTION
Technical Problem
[0010] However, in a case where the middle beam is welded to the
vehicle underfloor structure, it is necessary to perform the
welding over the entire length of the middle beam, which is
extremely complicated.
[0011] An object of the present invention is to provide an
underfloor double skin structure that can be easily positioned with
respect to a joining position of another double skin structure and
improve a strength of a vehicle underfloor structure with a simple
structure, the vehicle underfloor structure, and a vehicle.
Solution to Problem
[0012] According to an aspect of the present invention, in order to
solve the problem, there is provided an underfloor double skin
structure of an underfloor for a vehicle. The underfloor double
skin structure includes a first upper plate that extends in a
forward and rearward direction of the vehicle, a first lower plate
that extends in the forward and rearward direction of the vehicle,
the first lower plate being disposed to be spaced apart downward of
the first upper plate, and a first rib group that includes a
plurality of ribs, the plurality of ribs being integrally formed
with the first upper plate and the first lower plate, the plurality
of ribs being provided between the first upper plate and the first
lower plate, and the plurality of ribs being configured to connect
the first upper plate and the first lower plate with each other,
wherein the first upper plate includes a pair of first thin
portions and a first thick portion thicker than each of the pair of
first thin portions, the pair of first thin portions configuring
both end portions of the first upper plate in a width direction of
the vehicle, the first lower plate includes a pair of second thin
portions and a second thick portion thicker than each of the pair
of second thin portions, the pair of second thin portions
configuring the end portions of the first lower plate in the width
direction of the vehicle, the first rib group includes a pair of
thick ribs which are disposed to be spaced apart from each other in
the width direction of the vehicle, the pair of thick ribs being
configured to connect the first thick portion and the second thick
portion to each other, and each of the pair of thick ribs being
thicker than each of the first thin portion and the second thin
portion, and a reinforcing body is formed by the first thick
portion, the second thick portion, and the pair of thick ribs.
[0013] According to the present invention, the underfloor double
skin structure (including a reinforcing body that improves a
strength of a vehicle underfloor structure) including the first
upper plate, the first lower plate, and the first rib group is made
into an integral structure such that there is no necessity to weld
the reinforcing body to a lower surface side of the first lower
plate as a separate body from the first lower plate. Therefore, it
is possible to improve a strength of the vehicle underfloor
structure with a simple structure.
[0014] The both end portions of the first upper plate and the first
lower plate which are connected to another double skin structure in
the width direction of the vehicle are formed by the first thin
portions and the second thin portions such that it is possible to
easily deform the both end portions of the first upper plate and
the first lower plate in the width direction of the vehicle,
compared to the first thick portion and the second thick
portion.
[0015] Therefore, when the other double skin structure is joined to
the both end portions of the underfloor double skin structure in
the width direction of the vehicle, it is possible to easily
position ends of the underfloor double skin structure with respect
to ends of the other double skin structure.
[0016] In the underfloor double skin structure according to the
aspect of the present invention, the reinforcing body may partition
a plane perpendicular to the forward and rearward direction of the
vehicle to be a closed space.
[0017] In such configuration, since a groove or an opening does not
exist in a portion that partitions a space in the reinforcing body,
it is possible to suppress a decrease in strength of the
reinforcing body.
[0018] In the underfloor double skin structure according to the
aspect of the present invention, the second thick portion and the
pair of second thin portions may be disposed adjacent to one
another in a horizontal direction, and the second thick portion and
the pair of second thin portions may be integrally formed in the
width direction of the vehicle.
[0019] In such configuration, when the underfloor double skin
structure is manufactured using an extrusion forming method, a
warpage is less likely to occur in the underfloor double skin
structure during extrusion forming (during manufacturing).
Therefore, it is possible to easily manufacture the underfloor
double skin structure using the extrusion forming method.
[0020] In the underfloor double skin structure according to the
aspect of the present invention, the pair of thick ribs may extend
downward of the pair of second thin portions, and the second thick
portion may be disposed downward of the pair of second thin
portions.
[0021] According to such configuration, it is possible to match a
height of a lower surface of the double skin structure to a height
of a lower surface of the middle beam fixed to the lower surface
side of the double skin structure of the related art.
[0022] Therefore, it is possible to apply the underfloor double
skin structure to the vehicle underfloor structure without changing
specifications (for example, thickness, length, or the like) of a
member to be directly or indirectly connected to the second thick
portion.
[0023] In the underfloor double skin structure according to the
aspect of the present invention, the pair of thick ribs may connect
the first thick portion and the second thick portion to each other
in a vertical direction.
[0024] The pair of thick ribs that connect the first thick portion
and the second thick portion to each other in the vertical
direction is included such that it is possible to enhance the
strength of the reinforcing body against a load in an upward and
downward direction.
[0025] In the underfloor double skin structure according to the
aspect of the present invention, the first rib group may include a
pair of inclined ribs that connect the first thick portion and the
second thick portion to each other, and the pair of inclined ribs
may be inclined in a direction in which a distance between the pair
of inclined ribs increases from the second thick portion toward the
first thick portion.
[0026] According to such configuration, it is possible to release a
load that the second thick portion receives from a lower side
thereof in an oblique direction. Therefore, it is possible to
disperse the load that the second thick portion receives from the
lower side thereof.
[0027] In the underfloor double skin structure according to the
aspect of the present invention, the first thick portion and the
second thick portion may be flat plates, and the reinforcing body
may be bilaterally symmetrical with respect to a first plane which
passes through a center position of the reinforcing body, is
perpendicular to the first thick portion and the second thick
portion, and is parallel with the forward and rearward direction of
the vehicle.
[0028] According to such configuration, since a left half structure
and a right half structure of the reinforcing body have the same
structure, it is possible to decrease a difference in strength
between the left half structure and the right half structure of the
reinforcing body.
[0029] In the underfloor double skin structure according to the
aspect of the present invention, the first thick portion and the
second thick portion may be flat plates, and a structure including
at least the first thick portion, the second thick portion, and the
pair of thick ribs in the reinforcing body may be vertically
symmetrical with respect to a second plane which passes through an
intermediate position between the first thick portion and the
second thick portion, and is parallel with the first thick portion
and the second thick portion.
[0030] According to such configuration, it is possible to decrease
a difference in strength between upper and lower portions of the
reinforcing body.
[0031] In the underfloor double skin structure according to the
aspect of the present invention, the first thick portion and the
pair of first thin portions may be disposed adjacent to one another
in the horizontal direction, and the first thick portion and the
pair of first thin portions are integrally formed in the width
direction of the vehicle, and a structure including the pair of
first thin portions, the pair of second thin portions, the first
thick portion, the second thick portion, and the pair of thick ribs
may be vertically symmetrical with respect to a second plane which
passes through an intermediate position between the first thick
portion and the second thick portion, and is parallel with the
first thick portion and the second thick portion.
[0032] According to such configuration, when the underfloor double
skin structure is manufactured using the extrusion forming method,
warpage due to a thermal shrinkage during extrusion forming is less
likely to occur in the underfloor double skin structure during
manufacturing. Therefore, it is possible to form the structure
including the pair of first thin portions, the pair of second thin
portions, and the reinforcing body with high accuracy using the
extrusion forming method.
[0033] According to another aspect of the present invention, in
order to solve the problem, there is provided a vehicle underfloor
structure including the underfloor double skin structure, and
another double skin structure provided in a position adjacent to
the underfloor double skin structure in the width direction of the
vehicle, wherein the other double skin structure includes a second
upper plate that extends in the forward and rearward direction of
the vehicle, a second lower plate that is disposed to be spaced
apart downward of the second upper plate and extends in the forward
and rearward direction of the vehicle, and a second rib group that
is integrally formed with the second upper plate and the second
lower plate, is provided between the second upper plate and the
second lower plate, and connects the second upper plate and the
second lower plate to each other, in which an end of the second
upper plate is connected to an end of the first upper plate, and an
end of the second lower plate is connected to an end of the first
lower plate.
[0034] According to such configuration, it is possible to dispose
the underfloor double skin structure in a portion where
reinforcement is required and dispose the other double skin
structure that does not have the reinforcing body in a portion
where reinforcement is not required in the vehicle underfloor
structure, and join together (for example, friction stir joining)
the underfloor double skin structure and the other double skin
structure.
[0035] Therefore, since it is not necessary to weld the reinforcing
body to the double skin structure, it is possible to improve the
strength of the vehicle underfloor structure of the vehicle with a
simple structure.
[0036] According to still another aspect of the present invention,
in order to solve the problem, there is provided a vehicle
including the vehicle underfloor structure.
[0037] According to such configuration, it is possible to enhance
the strength of the vehicle underfloor structure against the load
received from a lower side thereof.
[0038] The vehicle according to the aspect of the present invention
may further include a bolster spring provided downward of a second
thick portion of the underfloor double skin structure.
[0039] According to such configuration, it is possible to enhance
the strength of the vehicle underfloor structure against the load
received from the lower side of the vehicle underfloor
structure.
Advantageous Effects of Invention
[0040] According to the present invention, it is possible to easily
position the end of the underfloor double skin structure with
respect to the end of another double skin structure and improve the
strength of the vehicle underfloor structure with a simple
structure.
BRIEF DESCRIPTION OF DRAWINGS
[0041] FIG. 1 is a front view showing a schematic configuration of
a vehicle according to a first embodiment of the present
invention.
[0042] FIG. 2 is a plan view of a vehicle underfloor structure and
a pair of side beams shown in FIG. 1.
[0043] FIG. 3 is a sectional view of the vehicle underfloor
structure shown in FIG. 2 in a direction of line
B.sub.1-B.sub.2.
[0044] FIG. 4 is an enlarged sectional view of an underfloor double
skin structure shown in FIG. 3.
[0045] FIG. 5 is an enlarged sectional view of the double skin
structure shown in FIG. 3.
[0046] FIG. 6 is a sectional view showing a schematic configuration
of an underfloor double skin structure according to a modification
example of the first embodiment of the present invention.
[0047] FIG. 7 is a sectional view showing a part of a vehicle
underfloor structure according to a second embodiment of the
present invention.
DESCRIPTION OF EMBODIMENTS
[0048] Hereinafter, embodiments to which the present invention is
applied will be described in detail with reference to the
drawings.
First Embodiment
[0049] A vehicle 10 of a first embodiment will be described with
reference to FIGS. 1 to 5. In FIG. 1, a track type vehicle is shown
as an example of the vehicle 10. In FIGS. 1 and 3 to 5, an X
direction denotes a width direction of the vehicle 10, and a Z
direction denotes an upward and downward direction and a height
direction (that is also a vertical direction) of the vehicle 10. In
FIG. 2, a Y direction denotes a forward and rearward direction of
the vehicle 10 which is perpendicular to the X direction and the Z
direction, and O.sub.1 denotes a center line O.sub.1 of an
underfloor double skin structure 32 which passes through a center
position A. The center position A is also an intermediate position
between a first thick portion 43 and a second thick portion 47.
[0050] In FIG. 4, A denotes a center position of a reinforcing body
40 (hereinafter, referred to as "center position A"), and L.sub.1
denotes a first plane which passes through the center position A,
is perpendicular to the first thick portion 43 and the second thick
portion 47, and is parallel with the Y direction (hereinafter,
referred to as "first plane L.sub.1"). In FIGS. 1 to 5, the same
reference signs will be assigned to the same configuration elements
as those of the structure shown in FIGS. 1 to 5.
[0051] In the first embodiment, the track type vehicle which is
guided by a side guide-type guide rail 3 provided on both sides of
a track 2 in a width direction and travels on a traveling path 4 of
the track 2 will be described as an example of the vehicle 10.
[0052] The vehicle 10 includes a vehicle body 15, a plate 17, a
bolt 18A, a nut 18B, and a traveling device 22.
[0053] The vehicle body 15 includes a vehicle underfloor structure
25 of an underfloor for the vehicle body, a pair of side beams 27A
and 27B, a pair of side walls 29A and 29B, and a ceiling (not
shown).
[0054] The vehicle underfloor structure 25 is provided between the
pair of side beams 27A and 27B disposed in a state of being
separated from each other in the X direction. The vehicle
underfloor structure 25 includes two underfloor double skin
structures 32 extending in the Y direction and three double skin
structures 33 (another double skin structure) extending in the Y
direction.
[0055] The vehicle underfloor structure 25 is configured such that
the double skin structures 33 and the underfloor double skin
structures 32 are alternately disposed in the X direction.
[0056] Each of the number of the underfloor double skin structures
32 and the number of the double skin structures 33 shown in FIGS. 1
and 2 is merely an example, and is not limited to these
numbers.
[0057] The underfloor double skin structure 32 includes a first
upper plate 35, a first lower plate 36, a first rib group 38, and
the reinforcing body 40. The underfloor double skin structure 32 is
manufactured, for example, by extrusion forming a lightweight alloy
such as an aluminum alloy.
[0058] The first upper plate 35 extends in the Y direction. The
first upper plate 35 includes a pair of first thin portions 41A and
41B and the first thick portion 43 of the reinforcing body 40.
[0059] The pair of first thin portions 41A and 41B extend in the Y
direction, and forms both end portions of the first upper plate 35
in the X direction. The first thin portion 41A includes an end 35A
disposed in the X direction. The first thin portion 41B includes an
end 35B disposed in the X direction.
[0060] Each of a pair of the ends 35A and 35B (both ends) is
connected to the double skin structure 33 disposed on each of both
sides of the underfloor double skin structure 32 through a joining
portion 60.
[0061] As the joining portion 60, for example, a friction stir
joining portion to be formed at the time of friction stir joining
can be used. In this case, the joining portions 60 are formed by
melting and then solidifying a material forming a part of the ends
35A and 35B of the first upper plate 35 and a material forming an
end of the double skin structure 33.
[0062] The first thick portion 43 extends in the Y direction, and
is provided between the first thin portion 41A and the first thin
portion 41B. The first thick portion 43 and the pair of first thin
portions 41A and 41B are disposed adjacent to one another in the
horizontal direction. The first thick portion 43 is integrally
formed with the pair of first thin portions 41A and 41B in the X
direction. That is, the first thick portion 43 and the pair of
first thin portions 41A and 41B are integrally formed with one
another.
[0063] The first thick portion 43 is a portion thicker than each of
the pair of first thin portions 41A and 41B. An upper surface 43a
of the first thick portion 43 is disposed at the same height as
that of an upper surface 41a of each of the pair of first thin
portions 41A and 41B in the Z direction. That is, an upper surface
35a of the first upper plate 35 which is formed of the upper
surface 41a of each of the pair of first thin portions 41A and 41B
and the upper surface 43a of the first thick portion 43 is
flat.
[0064] Therefore, the first thick portion 43 protrudes downward of
a lower surface 41b of the pair of first thin portions 41A and 41B.
The thickness of the first thick portion 43 can be set to, for
example, 2 to 4 times the thickness of each of the pair of first
thin portions 41A and 41B. As the first thick portion 43, for
example, a flat plate can be used.
[0065] The first lower plate 36 is disposed downward of the first
upper plate 35 in a state of being separated from the first upper
plate 35. The first lower plate 36 extends in the Y direction.
[0066] The first lower plate 36 includes a pair of second thin
portions 45A and 45B and a second thick portion 47 of the
reinforcing body 40.
[0067] The pair of second thin portions 45A and 45B extends in the
Y direction, and forms both end portions of the first lower plate
36 in the X direction. An upper surface 45a of each of the second
thin portions 45A and 45B faces the lower surface 41b of each of
the first thin portions 41A and 41B in the Z direction.
[0068] The second thin portion 45A includes an end 36A disposed in
the X direction. The second thin portion 45B includes an end 36B
disposed in the X direction.
[0069] Each of a pair of the ends 36A and 36B is connected to the
double skin structure 33 disposed on each of the both sides of the
underfloor double skin structure 32 through the joining portion
60.
[0070] A thickness of each of the pair of second thin portions 45A
and 45B can be, for example, the same as the thickness of each of
the pair of first thin portions 41A and 41B.
[0071] The second thick portion 47 is provided between the second
thin portion 45A and the second thin portion 45B. The thickness of
the second thick portion 47 is thicker than the thickness of each
of the pair of second thin portions 45A and 45B.
[0072] The second thick portion 47 and the pair of second thin
portions 45A and 45B are disposed adjacent to one another in the
horizontal direction. The second thick portion 47 is integrally
formed with the pair of second thin portions 45A and 45B in the X
direction. That is, the second thick portion 47 and the pair of
second thin portions 45A and 45B are integrally formed with one
another.
[0073] As such, the second thick portion 47 and the pair of second
thin portions 45A and 45B are integrally formed with one another in
the X direction, whereby it is possible to decrease a difference
between a position of the second thick portion 47 and a position of
each of the pair of second thin portions in the Z direction.
[0074] Therefore, when the underfloor double skin structure 32 is
manufactured using the extrusion forming method, the warpage is
less likely to occur in the underfloor double skin structure 32
during extrusion forming (during manufacturing). Thus, the
underfloor double skin structure 32 can be easily manufactured.
[0075] The second thick portion 47 faces the first thick portion 43
in a state of being separated downward of the first thick portion
43. Therefore, an upper surface 47a of the second thick portion 47
faces a lower surface 43b of the first thick portion 43.
[0076] The width of the second thick portion 47 in the X direction
can be, for example, the same size as a width of the first thick
portion 43 in the X direction. In addition, the thickness of the
second thick portion 47 can be, for example, the same as the
thickness of the first thick portion 43. As the second thick
portion 47, for example, a flat plate can be used.
[0077] The first rib group 38 is integrally formed with the first
upper plate 35 and the first lower plate 36. That is, the first rib
group 38 is integrally formed with the first upper plate 35 and the
first lower plate 36.
[0078] The first rib group 38 includes a pair of first vertical
ribs 51A and 51B, a pair of thick ribs 55A and 55B, and a pair of
first inclined ribs 56A and 56B of the reinforcing body 40, a pair
of second vertical ribs 53A and 53B, and a pair of second inclined
ribs 58A and 58B.
[0079] The pair of first vertical ribs 51A and 51B are disposed
between the first thick portion 43 and the second thick portion 47
in a state of being separated from each other in the X direction.
The pair of first vertical ribs 51A and 51B extend in the Y
direction. The pair of first vertical ribs 51A and 51B are
perpendicular to the first thick portion 43 and the second thick
portion 47.
[0080] The first vertical rib 51A connects one end of the first
thick portion 43 and one end of the second thick portion 47 to each
other in the Z direction. The first vertical rib 51B connects the
other end of the first thick portion 43 and the other end of the
second thick portion 47 to each other in the Z direction.
[0081] The thickness of each of the pair of first vertical ribs 51A
and 51B is thinner than the thickness of each of the first thick
portion 43 and the second thick portion 47. The thickness of each
of the pair of first vertical ribs 51A and 51B can be, for example,
the same as that of each of the first thin portions 41A and 41B and
the second thin portions 45A and 45B.
[0082] The second vertical rib 53A is provided between the first
thin portion 41A of one end portion of the first upper plate and
the second thin portion 45A of one end portion of the first lower
plate. The second vertical rib 53A extends in the Y direction.
[0083] The second vertical rib 53A is perpendicular to the first
thin portion 41A and the second thin portion 45A. The second
vertical rib 53A connects one end portion of the first thin portion
41A and one end portion of the second thin portion 45A to each
other in the Z direction.
[0084] The second vertical rib 53B is provided between the first
thin portion 41B of the other end portion of the upper plate and
the second thin portion 45B of the other end portion of the lower
plate. The second vertical rib 53B extends in the Y direction.
[0085] The second vertical rib 53B is perpendicular to the first
thin portion 41B and the second thin portion 45B. The second
vertical rib 53B connects the other end portion of the first thin
portion 41B and the other end portion of the second thin portion
45B to each other in the Z direction (upward and downward
direction).
[0086] The thickness of each of the pair of second vertical ribs
53A and 53B is thinner than the thickness of each of the first
thick portion 43 and the second thick portion 47. The thickness of
each of the pair of second vertical ribs 53A and 53B can be, for
example, the same as that of each of the first thin portions 41A
and 41B and the second thin portions 45A and 45B.
[0087] The pair of thick ribs 55A and 55B are disposed between the
first thick portion 43 and the second thick portion 47 in a state
of being separated from each other in the X direction. The pair of
thick ribs 55A and 55B are disposed between the first vertical rib
51A and the first vertical rib 51B.
[0088] The pair of thick ribs 55A and 55B extend in the Y
direction. The pair of thick ribs 55A and 55B are perpendicular to
the first thick portion 43 and the second thick portion 47. The
pair of thick ribs 55A and 55B connect the first thick portion 43
and the second thick portion 47 to each other in the Z
direction.
[0089] The thickness of each of the pair of thick ribs 55A and 55B
is thicker than the thickness of each of the first thin portions
41A and 41B, the second thin portions 45A and 45B, the pair of
first vertical ribs 51A and 51B, the pair of second vertical ribs
53A and 53B, the pair of first inclined ribs 56A and 56B, and the
pair of second inclined ribs 58A and 58B.
[0090] The thickness of each of the pair of thick ribs 55A and 55B
can be, for example, the same as the thickness of each of the first
thick portion 43 and the second thick portion 47.
[0091] As such, the first thick portion 43 and the second thick
portion 47 are connected to each other in the Z direction by the
pair of thick ribs 55A and 55B, whereby it is possible to enhance a
strength of the vehicle 10 against a load in the Z direction.
Therefore, it is possible to enhance a strength of the reinforcing
body 40 including the pair of thick ribs 55A and 55B.
[0092] The first inclined rib 56A is provided between the first
vertical rib 51A and the thick rib 55A. The first inclined rib 56A
extends in the Y direction.
[0093] The first inclined rib 56A is inclined in a direction from a
connection position between the second thick portion 47 and the
thick rib 55A toward a connection position between the first thick
portion 43 and the first vertical rib 51A. The first inclined rib
56A is inclined with respect to the first thick portion 43 and the
second thick portion 47. The first inclined rib 56A connects the
first thick portion 43 and the second thick portion 47 to each
other in an oblique direction.
[0094] The first inclined rib 56B is provided between the first
vertical rib 51B and the thick rib 55B. The first inclined rib 56B
extends in the Y direction.
[0095] The first inclined rib 56B is inclined in a direction (a
direction opposite to an inclination direction of the first
inclined rib 56A) from a connection position between the second
thick portion 47 and the thick rib 55B toward a connection position
between the first thick portion 43 and the first vertical rib 51B.
The first inclined rib 56B is inclined with respect to the first
thick portion 43 and the second thick portion 47. The first
inclined rib 56B connects the first thick portion 43 and the second
thick portion 47 to each other in the oblique direction.
[0096] The first inclined ribs 56A and 56B having such
configuration are inclined in a direction in which a distance
between the first inclined rib 56A and the first inclined rib 56B
increases from the second thick portion 47 toward the first thick
portion 43.
[0097] As such, the first inclined ribs 56A and 56B that connect
the first thick portion 43 and the second thick portion 47 to each
other and are inclined in a direction in which a distance increases
from the second thick portion 47 toward the first thick portion 43
are included, whereby it is possible to release a load that the
second thick portion 47 receives from a lower side thereof in the
oblique direction (the inclination direction of the first inclined
ribs 56A and 56B). Therefore, it is possible to disperse the load
that the second thick portion 47 receives from the lower side
thereof.
[0098] The second inclined rib 58A extends in the Y direction, and
is provided between the first vertical rib 51A and the second
vertical rib 53A. The second inclined rib 58A connects the first
thin portion 41A and the second thin portion 45A to each other in a
state of being inclined in a direction opposite to the first
inclined rib 56A provided at an adjacent position.
[0099] The second inclined rib 58B extends in the Y direction, and
is provided between the first vertical rib 51B and the second
vertical rib 53B. The second inclined rib 58B connects the other
first thin portion 41B and the other second thin portion 45B to
each other in a state of being inclined in a direction opposite to
the first inclined rib 56B provided at the adjacent position.
[0100] Shapes and the numbers of the first vertical ribs 51A and
51B, the second vertical ribs 53A and 53B, the first inclined ribs
56A and 56B, and the second inclined ribs 58A and 58B shown in FIG.
4 are merely examples, and are not limited to the shapes and
numbers shown in FIG. 4.
[0101] The reinforcing body 40 includes the first thick portion 43,
the second thick portion 47, the pair of first vertical ribs 51A
and 51B, the pair of thick ribs 55A and 55B, and the pair of first
inclined ribs 56A and 56B which are described above, and a space
62.
[0102] The space 62 is partitioned in the X direction and the Z
direction by the first thick portion 43, the second thick portion
47, and the thick ribs 55A and 55B. The space 62 extends in the Y
direction. The reinforcing body 40 partitions a plane (virtual
plane) perpendicular to the Y direction to be a closed space. The
reinforcing body 40 is disposed to surround the virtual plane.
[0103] The "closed space" in the present invention means a space in
which the space 62 does not communicate with another space (space
formed outside the space 62) disposed in the X direction and the Z
direction in a state where the underfloor double skin structure 32
and other parts are assembled and the underfloor double skin
structure 32 becomes a part of the vehicle 10.
[0104] As such, the space 62 partitioned by the first thick portion
43, the second thick portion 47, and the pair of thick ribs 55A and
55B is made into a closed space in a plane direction perpendicular
to the Y direction. In such configuration, since a groove or an
opening does not exist in a portion that partitions the space 62 in
the first thick portion 43, the second thick portion 47, and the
thick ribs 55A and 55B, it is possible to suppress a decrease in
strength of the reinforcing body 40.
[0105] It is preferable that the reinforcing body 40 is formed to
be bilaterally symmetrical with respect to the first plane L.sub.1
which passes through the center position A of the reinforcing body
40 and is perpendicular to the first thick portion 43 and the
second thick portion 47.
[0106] As such, the reinforcing body is formed to be bilaterally
symmetrical with respect to the first plane L.sub.1 which passes
through the center position A of the reinforcing body 40 and is
perpendicular to the first thick portion 43 and the second thick
portion 47. By such configuration, since a left half structure and
a right half structure of the reinforcing body 40 have the same
structure, it is possible to decrease a difference in strength
between the left half structure and the right half structure of the
reinforcing body 40.
[0107] In addition, it is preferable that a structure including the
first thick portion 43, the second thick portion 47, and the pair
of thick ribs 55A and 55B in the reinforcing body 40 is formed to
be vertically symmetrical with respect to a second plane L.sub.2
which passes through the intermediate position, including the
center position A of the reinforcing body 40, between the first
thick portion 43 and the second thick portion 47 and is parallel
with the first thick portion 43 and the second thick portion
47.
[0108] As such, the structure including at least the first thick
portion 43, the second thick portion 47, and the pair of thick ribs
55A and 55B in the reinforcing body 40 is formed to be vertically
symmetrical with respect to the second plane L.sub.2 which passes
through the center position A of the reinforcing body 40 and is
parallel with the first thick portion 43 and the second thick
portion 47, whereby it is possible to decrease a difference in
strength between upper and lower portions of the reinforcing body
40.
[0109] According to the underfloor double skin structure 32 of the
first embodiment, the underfloor double skin structure 32
(including the reinforcing body 40) including the first upper plate
35, the first lower plate 36, and the first rib group 38 is
integrally formed, whereby it is not necessary to weld the
reinforcing body for improving a strength of the vehicle underfloor
structure to a lower surface side of the first lower plate, as a
separate body from the first lower plate. Therefore, it is possible
to improve the strength of the vehicle underfloor structure 25 with
a simple structure.
[0110] The both end portions of the first upper plate 35 and the
first lower plate 36 to be connected to the double skin structure
33 in the X direction are formed of the first thin portions 41A and
41B and the second thin portions 45A and 45B, whereby it is
possible to displace the positions of the ends 35A, 35B, 36A, and
36B of the first upper plate 35 and the first lower plate 36 in the
X direction.
[0111] Therefore, when the double skin structure 33 is connected to
the ends 35A, 35B, 36A, and 36B of the underfloor double skin
structure 32 in the X direction, it is possible to easily position
the ends 35A, 35B, 36A, and 36B of the underfloor double skin
structure 32 and ends 66A, 66B, 67A, and 67B of the double skin
structure 33.
[0112] The double skin structure 33 includes a second upper plate
66, a second lower plate 67, and a second rib group 69.
[0113] The second upper plate 66 extends in the Y direction. The
second upper plate 66 is a plate having a uniform thickness. Each
of the ends 66A and 66B (both ends) of the second upper plate 66 in
the X direction is connected to any one of the side beam 27A, the
side beam 27B, the end 35A, and the end 35B through the joining
portion 60. The thickness of the second upper plate 66 can be, for
example, the same as that of each of the first thin portions 41A
and 41B.
[0114] The second lower plate 67 is disposed to be spaced apart
downward of the second upper plate 66 so as to face the second
upper plate 66. The second lower plate 67 extends in the Y
direction. The second lower plate 67 is a plate having a uniform
thickness.
[0115] Each of the ends 67A and 67B (both ends) of the second lower
plate 67 in the X direction is connected to any one of the side
beam 27A, the side beam 27B, the end 36A, and the end 36B through
the joining portion 60. The thickness of the second lower plate 67
can be, for example, the same as that of the second thick portion
47.
[0116] The second rib group 69 includes a plurality of third
vertical ribs 71 and a plurality of third inclined ribs 73.
[0117] The plurality of third vertical ribs 71 are provided between
the second upper plate 66 and the second lower plate 67. The
plurality of third vertical ribs 71 are disposed in the X direction
at predetermined intervals.
[0118] The plurality of third vertical ribs 71 extend in the Y
direction, and are perpendicular to the second upper plate 66 and
the second lower plate 67. The plurality of third vertical ribs 71
connect the second upper plate 66 and the second lower plate 67 to
each other. A space 74 partitioned in the Z direction by the second
upper plate 66 and the second lower plate 67 and extending in the Y
direction is formed between two adjacent third vertical ribs
71.
[0119] A thickness of the third vertical rib 71 can be, for
example, the same as that of each of the first thin portions 41A
and 41B and the second thin portions 45A and 45B.
[0120] The plurality of third inclined ribs 73 are provided in each
space 74. The plurality of third inclined ribs 73 connect the
second upper plate 66 and the second lower plate 67 to each other
in a state of being inclined with respect to the second upper plate
66 and the second lower plate 67. Two adjacent third inclined ribs
73 are inclined in different directions. A thickness of each of the
plurality of third inclined ribs 73 can be, for example, the same
as that of each of the first thin portions 41A and 41B and the
second thin portions 45A and 45B.
[0121] According to the vehicle underfloor structure 25 of the
first embodiment, the underfloor double skin structure 32 is
disposed in a portion where reinforcement is required and the
double skin structure 33 that does not have the reinforcing body 40
is disposed in a portion where reinforcement is not required in the
vehicle underfloor structure 25, and the underfloor double skin
structure 32 and the double skin structure 33 are joined together
(for example, friction stir joining), whereby it is possible to
form the vehicle underfloor structure 25.
[0122] Therefore, since it is not necessary to weld the reinforcing
body to the double skin structure, it is possible to improve the
strength of the vehicle underfloor structure 25 of the vehicle 10
with a simple structure.
[0123] The side beam 27A is joined to the double skin structure 33
of one end portion of the vehicle underfloor structure 25 in the X
direction. The side beam 27B is joined to the double skin structure
33 of the other end portion of the vehicle underfloor structure 25
in the X direction.
[0124] The side beams 27A and 27B are disposed so as to interpose
the vehicle underfloor structure 25 therebetween in the X
direction. As the side beams 27A and 27B, for example, the double
skin structure can be used.
[0125] The side wall 29A is provided on the side beam 27A. The side
wall 29A extends in the Z direction and the Y direction. A lower
end of the side wall 29A is connected to the side beam 27A through
a joining portion (not shown).
[0126] A side wall 29B is provided on the side beam 27B. The side
wall 29B extends in the Z direction and the Y direction. A lower
end of the side wall 29B is connected to the side beam 27B through
a joining portion (not shown). As the side walls 29A and 29B, for
example, the double skin structure can be used.
[0127] The ceiling (not shown) connects an upper end of the side
wall 29A and an upper end of the side wall 29B to each other. The
ceiling extends in the Y direction. As the ceiling, for example,
the double skin structure can be used.
[0128] The plate 17 is provided on a lower surface 47b of the
second thick portion 47. The plate 17 is fixed to the second thick
portion 47 by a bolt 18A penetrating the plate 17 and the second
thick portion 47, and a nut 18B provided on a shaft part of the
bolt 18A.
[0129] The traveling device 22 is a device that supports the
vehicle body 15 to be travelable from a lower side thereof. The
traveling device 22 is provided in each of front and rear parts of
the vehicle body 15.
[0130] The traveling device 22 includes an air spring 76 which is a
bolster spring, a damper 78, a motor (not shown), a drive shaft
(not shown), a gear box 81, an axle 83, and a pair of traveling
wheels 84, a suspension device (not shown), and a guide mechanism
86.
[0131] The air spring 76 is disposed between the plate 17 and a
bogie frame 88. The air spring 76 is fixed to a lower surface side
of the plate 17. Therefore, the air spring 76 is provided on the
lower surface 47b of the second thick portion 47 through the plate
17.
[0132] As such, the air spring 76 is provided on the plate 17 fixed
to the lower surface 47b of the second thick portion 47 of the
vehicle underfloor structure 25, whereby it is possible to enhance
the strength of the vehicle underfloor structure 25 against the
load received from a lower side of the vehicle underfloor structure
25 through the plate 17.
[0133] As the air spring 76, for example, a bag-like member made of
an elastic body (for example, rubber) capable of storing compressed
air therein can be used. As an example of the bolster spring, the
air spring 76 is described, but a bolster spring other than the air
spring 76 may be used.
[0134] The damper 78 is provided to connect the plate 17 and the
bogie frame 88 to each other.
[0135] The motor (not shown) generates rotational power using power
to be supplied from an outside. The drive shaft is connected to a
driving shaft of the motor. The motor is connected to the gear box
81 through the drive shaft.
[0136] A motor includes a casing (not shown) that covers an outside
thereof. The casing is attached to the lower surface of the vehicle
underfloor structure 25 through a vibration isolating material (not
shown) such as a vibration isolating rubber.
[0137] The gear box 81 accommodates a power transmission mechanism
such as a differential mechanism and a speed reduction mechanism.
The rotational power to be transmitted from the motor to the gear
box 81 is distributed to an axle shaft (not shown). The axle shaft
extends from the gear box 81 to both sides in the X direction and
is linked to each of the traveling wheels 84.
[0138] The axle 83 extends to the both sides in the X direction,
and a base thereof is connected to the gear box 81. The axle 83 is
rotatably supported by a pair of the bogie frames 88 disposed to be
separated from each other in the X direction.
[0139] A pair of the traveling wheels 84 are connected to an end
portion of the axle 83 extending to the both sides in the X
direction. As the wheel 84, for example, a tire wheel on which a
rubber tire is mounted can be used.
[0140] The suspension device (not shown) is a device for
transmitting a driving force and a braking force of the wheel 84 to
the vehicle body 15 while allowing the up and down movement of the
wheel 84 with respect to the vehicle body 15. The suspension device
includes the bogie frame 88, a traction link mechanism (not shown),
and a suspension frame (not shown).
[0141] The bogie frames 88 are disposed to be separated from each
other so as to interpose the gear box 81 therebetween in the X
direction. The bogie frames 88 rotatably support the axle 83.
[0142] The traction link mechanism (not shown) is provided on a
lower surface side of the vehicle underfloor structure 25. The
traction link mechanism transmits the force, such as the driving
force and the braking force by the wheel 84, acting on the vehicle
10 in the forward and rearward direction from the bogie frame 88 to
the suspension frame while allowing displacement of the bogie frame
88 in the Z direction with respect to the vehicle body 15.
[0143] The suspension frame (not shown) is provided on the lower
surface side of the vehicle underfloor structure 25. The suspension
frame (not shown) transmits the force in a traveling direction
transmitted through the traction link mechanism to the vehicle body
15.
[0144] The guide mechanism 86 is, for example, a mechanism that
changes a steering angle of the wheel 84 according to an arc shape
of a curved portion of the track 2 when the vehicle 10 travels on
the traveling path 4 of the track 2.
[0145] According to the vehicle 10 of the first embodiment, the air
spring 76 is provided on the plate 17 fixed to the lower surface
47b of the second thick portion 47 of the vehicle underfloor
structure 25, whereby it is possible to enhance the strength of the
vehicle underfloor structure 25 against the load received from the
lower side of the vehicle underfloor structure 25 through the plate
17.
[0146] Next, an underfloor double skin structure 90 according to a
modification example of the first embodiment will be described with
reference to FIG. 6. In FIG. 6, C denotes a center position of a
reinforcing body 91 (hereinafter, referred to as "center position
C"), D.sub.1 denotes a first plane which passes through the center
position C, is perpendicular to the first thick portion 43 and the
second thick portion 47, and is parallel with the Y direction (see
FIG. 2) (hereinafter, referred to as "first plane D.sub.1"), and
D.sub.2 denotes a second plane which passes through an intermediate
position, including the center position C, between the first thick
portion 43 and the second thick portion 47 and is parallel with the
first thick portion 43 and the second thick portion 47
(hereinafter, referred to as "second plane D.sub.2"). In addition,
in FIG. 6, the same reference signs will be assigned to the same
configuration elements as those of the structure shown in FIG.
4.
[0147] The underfloor double skin structure 90 has the same
configuration as that of the underfloor double skin structure 32
except that the underfloor double skin structure 90 has the
reinforcing body 91 instead of the reinforcing body 40 of the
underfloor double skin structure 32 of the first embodiment.
[0148] The reinforcing body 91 has the same configuration as that
of the reinforcing body 40 except that the lower surface 47b of the
second thick portion 47 is disposed to be flush with the lower
surface 45b of the second thin portions 45A and 45B.
[0149] The reinforcing body 91 having such configuration is
bilaterally symmetrical with respect to the first plane D.sub.1
which passes through the center position C of the reinforcing body
91 and is perpendicular to the first thick portion 43 and the
second thick portion 47.
[0150] A structure including the pair of first thin portions 41A
and 41B, the pair of second thin portions 45A and 45B, the first
thick portion 43, the second thick portion 47, and the pair of
thick ribs 55A and 55B is vertically symmetrical with respect to
the second plane D.sub.2 which passes through the center position C
of the reinforcing body 91 and is parallel with the first thick
portion 43 and the second thick portion 47.
[0151] As such, the structure including the pair of first thin
portions 41A and 41B, the pair of second thin portions 45A and 45B,
and the reinforcing body 91 is formed to be vertically symmetrical
with respect to the second plane D.sub.2 which passes through the
center position C of the reinforcing body 91 and is parallel with
the first thick portion 43 and the second thick portion 47. In such
configuration, when the underfloor double skin structure 90 is
manufactured using the extrusion forming method, a warpage due to a
thermal shrinkage is less likely to occur in the underfloor double
skin structure 90 during manufacturing.
[0152] Therefore, the structure including the pair of first thin
portions 41A and 41B, the pair of second thin portions 45A and 45B,
and the reinforcing body 91 can be formed with high accuracy using
the extrusion forming method.
Second Embodiment
[0153] A vehicle underfloor structure 100 according to a second
embodiment will be described with reference to FIG. 7. In FIG. 7, E
denotes a center position of a reinforcing body 105 (hereinafter,
referred to as "center position E"), and F.sub.1 denotes a first
plane which passes through the center position E and is
perpendicular to the first thick portion 43 and the second thick
portion 47 (hereinafter, referred to as "first plane F.sub.1"). In
addition, in FIG. 7, the same reference signs will be assigned to
the same configuration elements as those of the structure shown in
FIG. 3.
[0154] The vehicle underfloor structure 100 of the second
embodiment has the same configuration as that of the vehicle
underfloor structure 25 except that the vehicle underfloor
structure 100 has an underfloor double skin structure 101 instead
of the underfloor double skin structure 32 of the vehicle
underfloor structure 25 of the first embodiment.
[0155] The underfloor double skin structure 101 has the same
configuration as that of the underfloor double skin structure 32
except that the underfloor double skin structure 101 has a first
lower plate 103 and the reinforcing body 105 instead of the first
lower plate 36 and the reinforcing body 40 of the underfloor double
skin structure 32 of the first embodiment, and lower portions of
the pair of thick ribs 55A and 55B extend to positions downward of
the pair of second thin portions 45A and 45B.
[0156] The first lower plate 103 includes the pair of second thin
portions 45A and 45B, a third thin portion 107, and the second
thick portion 47. The third thin portion 107 is provided between
the second thin portion 45A and the second thin portion 45B. The
third thin portion 107 and the pair of second thin portions 45A and
45B are integrally formed with one another.
[0157] The third thin portion 107 connects the pair of second thin
portions 45A and 45B to each other in the X direction, and extends
in the Y direction. The thickness of the third thin portion 107 can
be, for example, the same as the thickness of each of the pair of
second thin portions 45A and 45B.
[0158] The second thick portion 47 is separated from the pair of
second thin portions 45A and 45B and the third thin portion 107.
The second thick portion 47 is disposed downward of the pair of
second thin portions 45A and 45B and the third thin portion 107 in
a state of being separated from the third thin portion 107.
Therefore, the first lower plate 103 of the second embodiment has
two-stage configuration.
[0159] Lower ends of the pair of thick ribs 55A and 55B are
integrally formed on an upper surface side of the second thick
portion 47. Therefore, the second thick portion 47 is supported at
a predetermined height downward of the third thin portion 107.
[0160] The reinforcing body 105 includes the first thick portion
43, the second thick portion 47, the pair of first vertical ribs
51A and 51B, the pair of thick ribs 55A and 55B, the pair of first
inclined ribs 56A and 56B, a part of the third thin portion 107,
and spaces 62 and 109.
[0161] The space 62 is partitioned in the X direction and the Z
direction by the first thick portion 43, the third thin portion
107, and the pair of thick ribs 55A and 55B. The space 62 extends
in the Y direction. The space 62 is formed as a closed space in the
plane direction (the plane direction including the X direction and
the Z direction) perpendicular to the Y direction.
[0162] The space 109 is a space formed downward of the space 62.
The space 109 is partitioned in the X direction and the Z direction
by the second thick portion 47, the third thin portion 107, and the
pair of thick ribs 55A and 55B. The space 109 extends in the Y
direction. The space 109 is formed as a closed space in the plane
direction (the plane direction including the X direction and the Z
direction) perpendicular to the Y direction.
[0163] As such, the spaces 62 and 109 formed in the reinforcing
body 105 are formed as the closed spaces in the plane direction
perpendicular to the Y direction. In such configuration, since a
groove or an opening is not formed in the first thick portion 43,
the second thick portion 47, the pair of thick ribs 55A and 55B,
and the third thin portion 107 of the reinforcing body 105, it is
possible to suppress a decrease in strength of the reinforcing body
105.
[0164] The reinforcing body 105 having such configuration is formed
to be bilaterally symmetrical with respect to the first plane
F.sub.1 which passes through the center position E of the
reinforcing body 105 and is perpendicular to the first thick
portion 43 and the second thick portion 47.
[0165] Therefore, since a left half structure and a right half
structure of the reinforcing body 105 have the same structure, it
is possible to decrease a difference in strength between the left
half structure and the right half structure of the reinforcing body
105.
[0166] According to the underfloor double skin structure 101 of the
second embodiment, the second thick portion 47 and the pair of
second thin portions 45A and 45B are separated from one another,
and the second thick portion 47 is disposed downward of the pair of
second thin portions 45A and 45B, whereby it is possible to match a
position of the lower surface 47b of the second thick portion 47 in
the height direction (Z direction) to a position of the lower
surface of the middle beam fixed to the lower surface of the double
skin structure of the related art in the height direction.
[0167] Therefore, it is possible to apply the underfloor double
skin structure 101 to the vehicle underfloor structure 100 without
changing specifications (for example, thickness, length, or the
like) of members to be directly or indirectly connected to the
second thick portion (in a case of the second embodiment, for
example, the plate 17, the air spring 76, and the bogie frame
88).
[0168] Preferred embodiments of the present invention have been
described in detail above, and the present invention is not limited
to specific embodiments. Various modifications and changes can be
made without departing from the concept of the present invention
described in the claims.
[0169] For example, in the first and second embodiments, the track
type vehicle has been described as an example of the vehicle, but
the underfloor double skin structures 32, 90, and 101 described in
the first and second embodiments are also applicable to vehicles
other than the track type vehicles.
INDUSTRIAL APPLICABILITY
[0170] The present invention is applicable to the underfloor double
skin structure, the vehicle underfloor structure, and the
vehicle.
* * * * *