U.S. patent application number 09/797736 was filed with the patent office on 2001-09-13 for structure of rear portion of automotive vehicle body.
This patent application is currently assigned to NISSAN MOTOR CO., LTD.. Invention is credited to Hanyu, Atsushi, Toba, Ryuichi.
Application Number | 20010020795 09/797736 |
Document ID | / |
Family ID | 18585883 |
Filed Date | 2001-09-13 |
United States Patent
Application |
20010020795 |
Kind Code |
A1 |
Toba, Ryuichi ; et
al. |
September 13, 2001 |
Structure of rear portion of automotive vehicle body
Abstract
A rear body of an automotive vehicle is provided which includes
three parts: a front body structural element, an intermediate body
structural element, and a rear body structural element which are
made of casts and joined together. The rigidity of the rear body is
increased from the rear body structural element to the front body
structural element, thereby facilitating the ease of a collapse of
the rear body structural element in response to input of a rear-end
collision impact for ensuring a protective structural area at a
front side of the rear body.
Inventors: |
Toba, Ryuichi;
(Yokohama-shi, JP) ; Hanyu, Atsushi;
(Yokosuka-shi, JP) |
Correspondence
Address: |
McDERMOTT, WILL & EMERY
600 13th Street, N.W.
Washington
DC
20005-3096
US
|
Assignee: |
NISSAN MOTOR CO., LTD.
|
Family ID: |
18585883 |
Appl. No.: |
09/797736 |
Filed: |
March 5, 2001 |
Current U.S.
Class: |
296/193.08 |
Current CPC
Class: |
B62D 25/08 20130101 |
Class at
Publication: |
296/195 |
International
Class: |
B60J 007/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 10, 2000 |
JP |
P2000-66534 |
Claims
What is claimed is:
1. A rear body of an automotive vehicle comprising: a front body
structural element made of a cast defining a front portion of the
rear body; and a rear body structural element made of a cast, said
rear body structural element being joined to said front body
structural element to define a rear portion of the rear body and
having a rigidity smaller than that of said front body structural
element.
2. A rear body as set forth in claim 1, further comprising an
intermediate body structural element joined between said first body
structural element and said rear body structural element, and
wherein said front body structural element defines body side
inners, said intermediate body structural element includes a rear
parcel and front portions of rear fender inners, and said rear body
structural element includes rear portions of the rear fender inners
and a rear end panel, and wherein a rigidity of the rear body
increases gradually from said rear body structural element to said
front body structural element through said intermediate body
structural element.
3. A rear body as set forth in claim 2, wherein said intermediate
body structural element has flanges formed on the front portions of
the rear fender inners, and said rear body structural element has
flanges formed on the rear portions of the rear fender inners, and
wherein said intermediate body structural element and said rear
body structural element are joined together by connecting the
flanges using a given fastening member.
4. A rear body as set forth in claim 2, wherein said rear body
structural element has provided in the front portions of the rear
fender inners easy-to-deform portions which serve to facilitate
ease of a collapse of the front portions of the rear fender inners
in is response to input of an impact force produced by a rear-end
collision of the vehicle.
5. A rear body as set forth in claim as set forth in claim 4,
wherein each of said easy-to-deform portions has a wall of the
front portion of one of the rear fender inners which bulges outward
along a vertical car line of the rear fender inner and is waved to
define troughs and ridges extending longitudinally of the rear
body, each of the ridges having formed in a central portion of a
length thereof a fragile portion which serves to induce a
corresponding one of the front portions of the rear fender inners
to be bent thereat in one of an inward and an outward direction in
response to input of an impact force produced by a rear-end
collision of the vehicle.
6. A rear body as set forth in claim 5, wherein at least one of the
fragile portions located outward of the rear body is offset
rearward of the fragile portions located inward of the rear
body.
7. A rear body as set forth in claim 4, wherein the rear end panel
has a load transmitting portion extending in a width-wise direction
of the rear body for transmitting the impact force produced by the
rear-end collision of the vehicle to the rear fender inners.
8. A rear body as set forth in claim 7, wherein the rear end panel
has a vertically extending fragile portion formed in a central
portion thereof in a width-wise direction of the rear body.
9. A rear body as set forth in claim 1, wherein the rear body
structural element comprises an energy absorbing portion for
absorbing an energy of collision impact.
10. A rear body as set forth in claim 9, wherein the energy
absorbing portion comprises an easy-to-deform portion.
11. A rear body as set forth in claim 10, wherein the
easy-to-deform portion comprises rigid portions and a fragile
portion between the rigid portions.
12. A rear body as set forth in claim 10, wherein the fragile
portions are disposed on the rear fender inner and the rear end
panel.
13. A rear body as set forth in claim 11, wherein the fragile
portion comprises a notch and the rigid portion comprises a
ridge.
14. A rear body as set forth in claim 11, wherein the fragile
portion serves as a pin engage portion when the rear body
structural element is withdrawn from a mold in a casting
process.
15. A rear body as set forth in claim 1, wherein a rigidity is
changed by changing a wall thickness.
16. A rear body as set forth in claim 3, further comprising ridges
connecting with the flange.
17. A rear body of an automotive vehicle comprising: front body
structural element means for defining a front portion of the rear
body; and rear body structural element means for defining a rear
portion of the rear body, said rear body structural element means
being joined to said front body structural element means and having
a rigidity smaller than that of said front body structural element
means.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Technical Field
[0002] The present invention relates generally to an improved
structure of a rear portion of an automotive vehicle body.
[0003] 2. Background Art
[0004] Japanese Patent First Publication No. 10-129533 shows a rear
body of a vehicle in which a reinforcement member is installed
diagonally to connect an end portion of each rear side member to an
end portion of a rear cross member across a joint of them to
increase the torsional rigidity of the rear portion of the vehicle
body, thereby distributing the energy of an impact force upon
occurrence of a rear-end collision of the vehicle to the rear side
members, the rear cross member, and rear wheel houses so as to
define an impact absorbing structural portion occupying a portion
of the vehicle body in front of the reinforcement members and a
vehicle body deformable portion occupying the remaining portion of
the vehicle body on the rear side of the reinforcement members.
[0005] Specifically, the above vehicle body structure is designed
to absorb the energy of an impact force produced by a rear-end
collision of the vehicle through structural members such as the
rear side members arranged at a lower portion of the vehicle body
and thus encounters the drawback in that it is very difficult to
distribute the energy of the impact force up to an upper portion of
the vehicle body effectively. Further, since the lower portion of
the vehicle body absorbs the energy of the impact force as a whole,
the need may arise for reconditioning or replacing the whole rear
portion of the vehicle body.
SUMMARY OF THE INVENTION
[0006] It is an object of the present invention to provide an
improved structure of a rear portion of an automotive vehicle body
which is designed to absorb the energy of impact produced by a
vehicle collision through both an upper and a lower portion of the
vehicle body.
[0007] According to one aspect of the invention, there is provided
a rear body of an automotive vehicle which comprises: a front body
structural element made of a cast defining a front portion of the
rear body; and a rear body structural element made of a cast. The
rear body structural element is joined to said front body
structural element to define a rear portion of the rear body and
has a rigidity smaller than that of the front body structural
element.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The present invention will be understood more fully from the
detailed description given hereinbelow and from the accompanying
drawings of the preferred embodiments of the invention, which,
however, should not be taken to limit the invention to the specific
embodiments but are for the purpose of explanation and
understanding only.
[0009] In the drawings:
[0010] FIG. 1 is an exploded perspective view which shows a rear
body of an automotive vehicle according to the first embodiment of
the invention;
[0011] FIG. 2 is an exploded perspective view which shows a rear
body according to the first embodiment of the invention;
[0012] FIG. 3 is a lateral sectional view which shows a front body
structural element, an intermediate body structural element, and a
rear body structural element of a rear body;
[0013] FIG. 4 is a perspective view which shows a collapse of a
rear fender inner in response to input of a collision impact
force;
[0014] FIG. 5 is a lateral sectional view which shows a collapse of
rear fender inners when a vehicle is involved in a full lap
rear-end collision;
[0015] FIG. 6 is a lateral sectional view which shows a collapse of
a rear fender inner when an impact force is applied to a half of a
rear end panel;
[0016] FIG. 7 is a lateral sectional view which shows a collapse of
a rear fender inner when an impact force is applied to a half of a
rear end panel from a diagonal direction;
[0017] FIG. 8 is a partial sectional view which shows a rear body
according to the second embodiment of the invention;
[0018] FIG. 9 is a partial sectional view which shows a rear body
according to the third embodiment of the invention; and
[0019] FIGS. 10 and 11 are partial perspective views which show a
modified form of an easy-to-deform portion of each rear fender
inner of a rear body structural element 4.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020] Referring now to the drawings, wherein like numbers refer to
like parts in several views, particularly to FIGS. 1, there is
shown an improved structure of a rear portion of an automotive
vehicle body according to the invention.
[0021] A rear body 1 is made of a lightweight metallic material
such as aluminum alloy and has three parts: a front body structural
element 2, an intermediate body structural element 3, and a rear
body structural element 4 which are arrayed longitudinally of a
vehicle body. The front body structural element 2 forms body side
inners. The intermediate body structural element 3 includes a rear
parcel 5 and a front portion 6F of each rear fender inner 6. The
rear body structural element 4 includes a rear portion 6R of each
of the rear fender inners 6 and a rear end panel 7. In the
following discussion, the front portions 6F and the rear portions
6R of the rear fender inners 6 will be referred to as a rear fender
inner of the intermediate body structural element 3 and a rear
fender inner of the rear body structural element 4,
respectively.
[0022] The rear body structural element 4 is lower in rigidity than
the intermediate body structural element 3. The rear body
structural element 4 is smaller in lateral cross section than the
intermediate body structural element 3. The rear body structural
element 3 decreases gradually in lateral cross section toward the
rear end panel 7. The wall thickness of the rear body 1 increases
from the rear body structural element 4 to the intermediate body
structural element 3 and to the front body structural element 2,
thereby increasing the rigidity of the rear body 1 gradually from
the rear body structural element 4 to the front body structural
element 2.
[0023] The intermediate body structural element 3 has flanges 8
formed on the rear fender inners 6F. Similarly, the rear body
structural element 4 has flanges 9 formed on the rear fender inner
6R. The intermediate body structural element 3 and the rear body
structural element 4 are joined to each other, as clearly shown in
FIG. 3, by connecting the flanges 8 and 9 together through
fastening members 10 such as rivets.
[0024] The rear body structural element 4 is, as discussed above,
smaller in lateral cross section thereof than the intermediate body
structural element 3. The flange 9 of the rear body structural
element 4 is bent outward, while the flange 8 of the intermediate
body structural element 3 is bent inward so that the flanges 8 and
9 may be brought into surface-to-surface contact.
[0025] The intermediate body structural element 3 has ribs 11
formed on an inner wall of each of the rear fender inners 6F in
contact with the flange 8 for transferring the impact acting on the
rear body structural element 4 upon occurrence of a rear-end
collision of the vehicle into an inplane pressure exerted on the
rear fender inner 6F.
[0026] The intermediate body structural element 3 is, as clearly
shown in FIG. 3, lapped partially in the front body structural
element 2 and welded as indicated at W.
[0027] The intermediate body structural element 3 is, as described
above, smaller in wall thickness than the front body structural
element 2 as a whole, however, it has a thick end portion welded to
the front body structural element 2 whose thickness is
substantially equal to that of the front body structural element 2
for increasing the strength of connection between the intermediate
body structural element 3 and the front body structural element
2.
[0028] The front body structural element 2 has a plurality of ribs
12 formed integrally on an inner wall thereof which are in contact
with the end of the intermediate body structural element 3 when the
front body structural element 2 and the intermediate body
structural element 3 are joined together, thereby transferring the
collision impact transmitted from the intermediate body structural
element 3 into an inplane pressure acting on the front body
structural element 2. The ribs 12 also work as stoppers which
assist in positioning the front body structural element 2
longitudinally when joined to the intermediate body structural
element 3.
[0029] The rear body structural element 4 has formed in each of the
rear fender inners 6R an easy-to-deform portion 21 which serves to
facilitate a collapse of the rear fender inner 6R in response to
input of the impact produced by the rear-end collision of the
vehicle.
[0030] Each of the easy-to-deform portions 21 has V-shaped grooves
22 formed at given vertical intervals in an outer wall of one of
the rear fender inner 6R bulging outward along a vertical car line.
The grooves 22 extend longitudinally of the vehicle body and define
ridges 23 on an inner wall of each of the rear fender inners 6R.
Each of the ridges 23 has a notch 24 formed in the longitudinal
center thereof which serves to induce a corresponding one of the
rear fender inners 6R to be collapsed easily so that the grooves 22
may be opened vertically when the vehicle is involved in a rear-end
collision.
[0031] The grooves 22 extend from the flange 9 of each of the rear
fender inners 6R to the rear end of the rear fender inner 6R. Each
of the notches 24 also serves as a step with which an end of an
ejector pin (not shown) engages when the rear body structural
element 4 is withdrawn (in a longitudinal direction of the vehicle
body in the drawing) from a mold in a casting process.
[0032] Two of the notches 24 which are, as indicated at 24a in FIG.
3, formed in the ridges 23 of each of the rear fender inners 6R
located outward in a width-wise direction of the vehicle body are
offset rearward of two of the notches 24, as indicated at 24b,
located inward in the width-wise direction of the vehicle body.
[0033] The rear end panel 7 has an upper half which extends in the
width-wise direction of the vehicle body and bulges outward to
define a trunk lid receiver 7A and a lower half which bulges inward
and has side member mounts 7B formed on ends thereof.
[0034] The trunk lid receiver 7A has, as clearly shown in FIG. 2, a
load transmitting means 25 formed over a length thereof which works
to transmit a rear-end collision impact force to the rear fender
inners 6. The load transmitting means 25 is made up of diagonal
ribs 25a and vertical ribs 25b provided within a recess formed in
an inner wall of the trunk lid receiver 7A. The diagonal ribs 25a
extend in a wave form within the trunk lid receiver 7A between the
side member mounts 7B. The vertical ribs 25b are arranged outside
the diagonal ribs 25a.
[0035] The trunk lid receiver 7A has formed in a central portion of
an upper surface thereof a striker receiver 26 into which a striker
of a lock mechanism of a trunk (not shown) is fitted. The trunk lid
receiver 7A also has a upright bead 27 which is formed by bulging a
central portion of a rear wall thereof inward as serving as a
fragile portion.
[0036] To the inside wall of the side member mounts 7B of the rear
body structural element 4, side members (not shown) are joined,
while to the outside wall thereof, member extensions (not shown)
are joined in alignment with the side members. Each of the side
member mounts 7B has, as shown in FIG. 1, a vertical rib 28 which
is formed on the outside wall thereof and extends up to an outer
bottom wall of the trunk lid receiver 7A for increasing the
rigidity thereof.
[0037] As described above, the rear body 1 is made up of three cast
parts: the front body structural element 2, the intermediate body
structural element 3, and the rear body structural element 4 which
are arrayed longitudinally of the vehicle body. The wall thickness
of the rear body 1 increases from the rear body structural element
4 to the intermediate body structural element 3 and to the front
body structural element 2, and the rear body structural element 4
decreases in lateral cross section gradually, thereby increasing
the rigidity of the rear body 1 from the rear body structural
element 4 to the front body structural element 2. This induces the
rear body 1 to be collapsed in the order of the rear body
structural element 4, the intermediate body structural element 3,
and the front body structural element 2 when the vehicle is
involved in a rear-end collision of the vehicle. Specifically, the
rear body 1 absorbs the energy of collision impact as a whole as
well as the absorption by lower portions of the rear side
members.
[0038] The rigidity of the rear body 1, as described above,
increases from the rear body structural element 4 to the
intermediate body structural element 3 and to the front body
structural element 2, that is, as approaching the vehicle cabin.
Specifically, the rear body 1 is so designed as to have the
greatest resistance to the collapse caused by a rear-end collision
in the front body structural element 2 and induce the rear body
structural element 4 to be collapsed easily, thereby minimizing the
amount of collapse of the front body structural element 2 and the
intermediate body structural element 3 to provide a protective
structural area as great as possible to the front of the rear body
1 close to the vehicle cabin.
[0039] In the event of a light rear-end collision, only the rear
body structural element 4 is collapsed, which allows the rear body
1 to be reconditioned only by fixing or replacing the rear body
structural element 4. Particularly, the rear body structural
element 4 and the intermediate body structural element 3 are joined
by connecting the flanges 9 and 8 using the fastening members 10,
thus allowing the rear body structural element 4 to be replaced
easily only by removing the fastening member 10 from the flanges 8
and 9.
[0040] Further, the joining of the rear body structural element 4
and the intermediate body structural element 3 using the flanges 9
and 8 increases the degree of transmission of the rear-end
collision impact force from the rear body structural element 4 to
the front body structural element 2 through the intermediate body
structural element 3 and also ensures a higher resistance of the
rear body structural element 4 to the collapse.
[0041] The rear body structural element 4, as described above, has
formed in each of the rear fender inners 6R the easy-to-deform
portion 21 serving to facilitate a collapse of the rear fender
inner 6R in response to an impact force produced by the rear-end
collision of the vehicle. Additionally, the trunk lid receiver 7A
of the rear end panel 7 has the load transmitting means 25 which
works to transmit the rear-end collision impact force to the rear
fender inners 6. The rear-end collision impact force is, thus,
transmitted to the right and left rear fender inners 6R effectively
to induce the collapse of the rear fender inners 6R from the
easy-to-deform portions 21, thereby resulting in collapse of the
rear body structural element 4 in an optimum deformation mode.
[0042] Each of the easy-to-deform portions 21 has the V-shaped
grooves 22 extending in parallel at a given vertical interval and
the notches 24 formed in the central portions of the ridges 23
defined by the grooves 22 so that the rear fender inners 6R may be
bent inward at the notches 24 upon input of the rear-end collision
impact force, causing the grooves 23 to be opened vertically.
Specifically, the collapse of each of the rear fender inners 6R
includes, as shown in FIG. 4, the vertical deformation of the
grooves 22 and an outward bulge thereof, thereby absorbing the
energy of the rear-end collision impact effectively.
[0043] For example, when the vehicle is involved in the so-called
full lap collision in which an impact force F. as shown in FIG. 5,
acts on the rear end panel 7 from a perpendicular direction, the
impact force F is distributed equally to the right and left rear
fender inners 6R through the load transmitting means 25, so that
the stress concentrates at the notches 24 formed in the ridges 23
of the easy-to-deform portions 21, thereby causing the rear fender
inners 6R to bulge outward at the notches 24 and the grooves 22 to
be opened vertically.
[0044] The notches 24a which are formed in the ridges 23 defined by
the grooves 22a located outward of the vehicle body are, as
described above, offset rearward of the notches 24b formed on the
ridges 23 defined by the grooves 22b located inward of the vehicle
body, thereby causing an outward bulging portion of each of the
rear fender inners 6R which is difficult to deform to be collapsed
earlier so that the rear fender inners 6R are collapsed in a
desired mode.
[0045] Additionally, the longitudinal offset of the notches 24a and
24b avoids the interference of the vertical deformation of the
grooves 22a with that of the grooves 22b, thereby enhancing the
efficiency in absorbing the energy of collision impact.
[0046] FIG. 6 shows a collapse of the rear end panel 7 when the
vehicle is involved in the so-called offset rear-end collision in
which the impact force F is applied to a half of the rear end panel
7 from a perpendicular direction. In this case, the impact force F
acts only on one of the rear fender inners 6R located on the
collision side, but the bead 27 extending vertically in the central
portion of the rear end panel 7 works as a fragile portion to
induce the rear end panel 7 to be bent at the center thereof, so
that the impact force F is transmitted as the moment of force to
the other rear fender inner 6R on the non-collision side. This
causes the rear fender inner 6R on the non-collision side to be
collapsed through the easy-to-deform portion 21, thereby absorbing
the impact force F completely. Substantially the same collapse of
the rear end panel 7 is also taken place when the impact force F
acts, as shown in FIG. 7, on the rear end panel 7 from a diagonal
direction.
[0047] FIG. 8 shows the rear body 1 according to the second
embodiment of the invention which is different from the first
embodiment in a connection of the front body structural element 2
and the intermediate body structural element 3. Other arrangement
are identical, and explanation thereof in detail will be omitted
here.
[0048] The front body structural element 2 has a flange 14 bent
inward. The intermediate body structural element 3 has a flange 15
bent outward. The front body structural element 2 and the
intermediate body structural element 3 are jointed by welding the
flange 15 on the flange 14, as indicated at W. A plurality of ribs
16 are formed on an inner corner of the flange 14 to transfer an
impact force produced by a rear-end collision of the vehicle into
an inplane pressure acting on the front body structural element
2.
[0049] FIG. 9 shows the rear body 1 according to the third
embodiment of the invention which is different from the first
embodiment in a connection of the intermediate body structural
element 3 and the rear body structural element 4. Other arrangement
are identical, and explanation thereof in detail will be omitted
here.
[0050] The rear body structural element 4 is lapped at an end
portion thereof over the intermediate body structural element 3 and
joined together by fastening members 10 such as rivets.
[0051] A plurality of ribs 17 are formed integrally on an inner
wall of the intermediate body structural element 3 which are in
contact with an end of the rear body structural element 4 when the
intermediate body structural element 3 is joined to the rear body
structural element 4 for transferring a rear-end collision impact
force exerted on the rear body structural element 4 into an inplane
pressure acting on the intermediate body structural element 3. The
ribs 17 also serve as stoppers for positioning the rear body
structural element 4 when fitted into the intermediate body
structural element 3.
[0052] FIGS. 10 and 11 show a modification of the easy-to-deform
portion 21 of each of the rear fender inners 6R of the rear body
structural element 4.
[0053] The easy-to-deform portion 21 is made of a wall which is
corrugated to define V-shaped troughs 22 and peaks 32 extending
horizontally and which bulges, like the first embodiment, outward
as a whole along a vertical car line of the rear fender inner 6R.
The V-shaped troughs 22 have substantially the same length as that
of the grooves 22 in the first embodiment. Each of the peaks 32 has
a notch 34 formed in a central portion of the ridge 33 for inducing
the rear fender inner 6R to be collapsed easily at the notches 34
when a rear-end collision impact force F, as shown in FIG. 11, is
applied to the rear end panel 7.
[0054] Two of the notches 34, as indicated at 34a, which are formed
in the peaks 32a located outward in the width-wise direction of the
vehicle body are offset, like the first embodiment, rearward of two
of the notches 34, as indicated at 34b, located inward in the
width-wise direction of the vehicle body, thereby causing an
outmost portion of each of the rear fender inners 6R to be
collapsed earlier so that the rear fender inner 6R is collapsed in
a desired mode.
[0055] Additionally, the longitudinal offset of the notches 34a and
34b also serves to avoid the interference of inward bends of the
outer peaks 32a at the notches 34a with those of the inner peaks
32b at the notches 34b, thereby enhancing the efficiency in
absorbing the energy of collision impact.
[0056] Notches, like the first embodiment, may also be formed in
the inner wall (i.e., the troughs 22) of the rear fender inners
6R.
[0057] As apparent from the above discussion, the structure of the
rear body 1 is so designed as to facilitate the ease of collapse of
a rear portion thereof (i.e., the rear body structural element 4)
for absorbing the energy of a collision impact force acting on the
rear of the vehicle body in an ideal mode to provide an occupant
protective area on the front side of the rear body 1. Further, the
rear body 1 is fabricated by three cast parts: the front body
structural element 2, the intermediate body structural element 3,
and the rear body structural element 4, thus decreasing the number
of parts and production processes greatly as compared with a
conventional structure of a rear body made by assembling many panel
members. The assembly of the vehicle body may be accomplished by
preparing a subassembly made up of the body structural elements 2,
3, and 4 and then joining it to a front body, thereby facilitating
the ease of automatic assembly of the vehicle body and resulting in
a decrease in manufacturing cost.
[0058] The rear body 1 may alternatively be made up of two separate
cast parts: one being an one-piece structural member including the
front body structural element 2 and the intermediate body
structural element 2 integrally and the other being the rear body
structural element 4.
[0059] The entire contents of Japanese Patent Application No.
2000-66534 (filed on Mar. 10, 2000) is incorporated herein by
reference.
[0060] While the present invention has been disclosed in terms of
the preferred embodiments in order to facilitate better
understanding thereof, it should be appreciated that the invention
can be embodied in various ways without departing from the
principle of the invention. Therefore, the invention should be
understood to include all possible embodiments and modifications to
the shown embodiments which can be embodied without departing from
the principle of the invention as set forth in the appended
claims.
* * * * *