U.S. patent application number 12/380839 was filed with the patent office on 2009-09-10 for air bag system for vehicle.
This patent application is currently assigned to Honda Motor Co., Ltd.. Invention is credited to Hitoshi Higuchi.
Application Number | 20090224520 12/380839 |
Document ID | / |
Family ID | 41052829 |
Filed Date | 2009-09-10 |
United States Patent
Application |
20090224520 |
Kind Code |
A1 |
Higuchi; Hitoshi |
September 10, 2009 |
Air bag system for vehicle
Abstract
The present invention preferably regulates discharge rate of the
gas filling the air bag body from the vent hole provided in the air
bag body. There is provided a bend section for applying
tensile-force onto the pair of the faces to pull the faces in the
longitudinal direction apart from the vent hole. When predetermined
tensile-force is applied onto the pair of the faces, the faces
become closed and sealed. Meanwhile, when smaller tensile-force
than the predetermined tensile-force is applied, the pair of the
faces become apart from each other and opened, so that the gas is
discharged from this opening of the faces.
Inventors: |
Higuchi; Hitoshi; (Saitama,
JP) |
Correspondence
Address: |
CARRIER BLACKMAN AND ASSOCIATES
43440 WEST TEN MILE ROAD, EATON CENTER
NOVI
MI
48375
US
|
Assignee: |
Honda Motor Co., Ltd.
Tokyo
JP
|
Family ID: |
41052829 |
Appl. No.: |
12/380839 |
Filed: |
March 4, 2009 |
Current U.S.
Class: |
280/740 |
Current CPC
Class: |
B60R 21/239
20130101 |
Class at
Publication: |
280/740 |
International
Class: |
B60R 21/26 20060101
B60R021/26 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 7, 2008 |
JP |
2008-057304 |
Dec 29, 2008 |
JP |
2008-335606 |
Claims
1. An air bag system for a vehicle comprising an air bag body
formed by stitching base fabric material, an inflator that charges
the air bag body with gas, and a vent hole that is a through hole
provided in the air bag body so as to communicate the inside with
the outside of the air bag body, wherein the vent hole of the air
bag body is formed to be longer in a longitudinal direction
thereof, and the air bag body comprises: a tensile-force applying
means that applies tensile-force in the longitudinal direction of
the vent hole; a pair of faces provided along the gas discharge
direction from the vent hole; and a flow-passage restriction
membrane provided along the longitudinal direction of the vent
hole.
2. The air bag system for a vehicle according to the claim 1,
wherein the air bag body is constituted by plural basic fabric
pieces, and the vent hole is provided in a stitched section where
at least two pieces of the plural basic fabric pieces are stitched,
and the stitched section comprises a neck portion that is set in a
direction from the outside toward the inside of the air bag body,
so that, when the air bag body is inflated and expanded, an outer
circumferential length passing through a longitudinal end of the
vent hole of the air bag body is locally reduced so as to be
shorter than an outer circumferential length extending outer side
from the vent hole.
3. The air bag system for a vehicle according to the claim 1,
wherein the air bag body is constituted by plural basic fabric
pieces, the vent hole is provided in a stitched section where at
least two pieces of the plural basic fabric pieces are stitched,
the stitched section comprises a bend section recessed in curve
toward the inside of the air bag body, so that, when the air bag
body is inflated and expanded, an outer circumferential length
passing through a longitudinal end of the vent hole of the air bag
body is locally reduced so as to be shorter than an outer
circumferential length extending outer side from the vent hole, and
an end-support that supports both side ends of the faces, and the
bend section comprises the tensile-force applying means.
4. The air bag system for a vehicle according to the claim 1,
wherein the tensile-force applying means is provided in the
vicinity of the longitudinal ends of the vent hole, and comprises
at least one strap member for reducing an outer circumferential
length of the air bag body passing through a longitudinal end of
the vent hole.
5. The air bag system for a vehicle according to the claim 1,
wherein the pair of the faces are formed in an asymmetrical
shape.
6. The air bag system for a vehicle according to the claim 2,
wherein the pair of the faces are formed in an asymmetrical
shape.
7. The air bag system for a vehicle according to the claim 3,
wherein the pair of the faces are formed in an asymmetrical
shape.
8. The air bag system for a vehicle according to the claim 1,
wherein the flow-passage restriction membrane is provided inside
the air bag body.
9. The air bag system for a vehicle according to the claim 2,
wherein the flow-passage restriction membrane is provided inside
the air bag body.
10. The air bag system for a vehicle according to the claim 3,
wherein the flow-passage restriction membrane is provided inside
the air bag body.
11. The air bag system for a vehicle according to the claim 1,
wherein the longitudinal direction of the vent hole extends from
the upper front side to the lower rear side of the vehicle.
12. The air bag system for a vehicle according to the claim 2,
wherein the longitudinal direction of the vent hole extends from
the upper front side to the lower rear side of the vehicle.
13. The air bag system for a vehicle according to the claim 3,
wherein the longitudinal direction of the vent hole extends from
the upper front side to the lower rear side of the vehicle.
14. An air bag system for a vehicle comprising: an air bag body
formed in a bag form, an inflator that charges the air bag body
with gas and a vent hole provided in the air bag body so as to
discharge the gas filling the air bag body, wherein the air bag
body comprises: a pair of faces that are provided around the vent
hole to form the vent hole in a slit-like shape extending in one
direction; and a tensile-force applying section that applies
tensile-force onto the pair of the faces in the longitudinal
direction apart from the vent hole, and the pair of the faces
becomes closed and sealed when the tensile-force applying section
applies predetermined tensile-force onto the pair of the faces, and
the pair of the faces become apart from each other and opened when
the tensile-force applying section applies smaller tensile-force
than the predetermined tensile-force onto the pair of the faces, so
that the gas filling the air bag body is discharged from the
opening of the pair of the faces.
15. An air bag system for a vehicle comprising: an air bag formed
by stitching basic fabric material, an inflator that charges the
air bag body with gas, and a vent hole that is a through hole
provided in the air bag body so as to communicate the inside with
the outside of the air bag body, wherein the vent hole for
discharging the gas filling the air bag body is formed to be a long
slit along the direction to restrict the expansion of the air bag.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the foreign priority benefit under
35 U.S.C. .sctn.119 of Japanese Patent Applications No. 2008-057304
filed on Mar. 7, 2008 and No. 2008-335606 filed on Dec. 29, 2008,
the disclosures of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to an air bag system for a
vehicle to protect an occupant.
[0004] 2. Description of the Related Art
[0005] Conventionally, there has been known an air bag system for a
vehicle that is inflated and expanded by gas supplied from an
inflator to constrain an occupant's movement so as to protect him
or her at the time of a collision of the vehicle.
[0006] In such an air bag system for a vehicle, it has been
proposed to provide a vent hole (discharge port) on an air bag (bag
body), through which gas is discharged into the air bag.
[0007] JP H06-286569 A discloses, for example, an air bag system
for a vehicle, in which, in order to reduce impact of an air bag
onto an occupant when the occupant hits the air bag inflated and
expanded, there is provided a slot-like vent hole and an elastic
member provided across the vent hole, so that each end of the
elastic member is fixed onto the air bag.
[0008] When an inflated and expanded air bag comes in contact with
and presses an obstacle and the like, it is preferable to restrain
inflation and expansion of the air bag by increasing the
discharging rate of gas in the air bag from the vent hole. However,
a conventional air bag system for a vehicle, as disclosed in JP
H06-286569 A, discharges gas in the air bag from the vent hole at
an approximately constant rate even when the inflated and expanded
air bag comes in contact with and presses an obstacle, and
discloses or suggests nothing about regulation of discharging rate
of gas in the air bag.
[0009] In the air bag system disclosed in JP H06-286569 A, gas
filling the air bag is constantly leaked from the vent hole during
the process of inflating and expanding the air bag, which delays
sufficient increase of internal pressure of the air bag by the
leaked gas amount, taking more time to blow up the air bag, and
consequently to hinder a quick inflation and expansion of the air
bag.
[0010] In addition, it is preferable to maintain gas pressure in
the air bag until an occupant is sufficiently restrained by the
inflated and expanded air bag. However, the conventional air bag
system for a vehicle disclosed in JP H06-286569 A keeps the vent
hole open even during the inflation and expansion of the air bag,
thus it is difficult to maintain the gas pressure in the air bag at
a constant rate, which sufficiently restrains the occupant.
[0011] In the light of the above various difficulties, the present
invention has an object to preferably regulate discharging rate of
gas filling in an air bag body from a vent hole when the air bag
body comes in contact with and presses an obstacle and the like
during the inflation and expansion of the air bag body, but quickly
expand the air bag body with the vent hole closed if not coming in
contact with the obstacle as well as maintaining the gas pressure
in the air bag body at a constant rate.
SUMMARY OF THE INVENTION
[0012] In one aspect of the present invention, there is provided an
air bag system for a vehicle including an air bag body formed by
stitching base fabric material, an inflator that charges the air
bag body with gas, and a vent hole that is a through hole provided
in the air bag body so as to communicate the inside with the
outside of the air bag body, wherein the vent hole of the air bag
body is formed to be long in one direction, and the air bag body
includes: a tensile-force applying means that applies tensile-force
in the longitudinal direction of the vent hole; a pair of faces
provided along the gas discharge port of the vent hole; and a
flow-passage restriction membrane provided along the longitudinal
direction of the vent hole.
[0013] In another aspect of the present invention, there is
provided an air bag system for a vehicle including an air bag body
formed in a bag form, an inflator that charges the air bag body
with gas and a vent hole provided in the air bag body for
discharging the gas filling the air bag body, wherein the air bag
body includes: a pair of faces that is provided around the vent
hole to form the vent hole in a slit-like shape extending in one
direction; and a tensile-force applying section that applies
tensile-force onto the pair of the faces in the longitudinal
direction apart from the vent hole, and the pair of the faces
becomes closed and sealed when the tensile-force applying section
applies predetermined tensile-force onto the pair of the faces, and
the pair of the faces become apart from each other and opened when
the tensile-force applying section applies smaller tensile-force
than the predetermined tensile-force onto the pair of the faces, so
that the gas filling the air bag body is discharged from the
opening of the pair of the faces.
[0014] In yet another aspect of the present invention, there is
provided an air bag system for a vehicle including an air bag
formed by stitching basic fabric material, an inflator that charges
the air bag body with gas, and a vent hole that is a through hole
provided in the air bag body so as to communicate the inside with
the outside of the air bag body, wherein the vent hole for
discharging the gas filling the air bag body is formed to be a long
slit along the direction to restrict the expansion of the air
bag.
[0015] Other features and advantages of the present invention will
become more apparent from the following detailed description of the
invention when taken in conjunction with the accompanying exemplary
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a schematic perspective view of an air bag system
for a vehicle according to an embodiment of the present invention,
which is installed to a front passenger seat where the air bag body
is inflated and expanded.
[0017] FIG. 2 is a schematic side view of FIG. 1.
[0018] FIG. 3 is a perspective view showing a state in which the
air bag body that is inflated and expanded.
[0019] FIG. 4 is a perspective view showing how to contactedly
overlap two pieces of base fabric material and stitch the two
pieces in a curve line so as to form a vent hole.
[0020] FIG. 5A is a plan view simplifying the stitched portion of
FIG. 4.
[0021] FIG. 5B is a transparent view showing a state in which inner
pressure is applied by the filling gas after turning over the bag
body 12 stitched at the stitched portion of FIG. 4 front side
out.
[0022] FIG. 6 is a perspective view showing the stitched portion
with an L-shaped line provided on the contactedly overlapped two
pieces of the base fabric material.
[0023] FIG. 7A is a plan view simplifying the stitched line of FIG.
6.
[0024] FIG. 7B is a transparent view showing a state in which inner
pressure is applied by the filling gas after the stitched air bag
body 12 is turned over with the front side out.
[0025] FIG. 8 is a perspective view showing the stitched portion
with a V-shaped line provided on the contactedly overlapped two
pieces of the base fabric material, according to the second
variation of the present embodiment.
[0026] FIG. 9A is a plan view simplifying the stitched portion of
FIG. 8.
[0027] FIG. 9B is a transparent view showing a state in which inner
pressure is applied by the filling gas after the stitched air bag
body 12 is turned over with the front side out.
[0028] FIG. 10A is a perspective view showing a state in which the
stitched air bag body 12 of FIG. 9A is turned over with the front
side out.
[0029] FIG. 10B is a perspective view showing a state in which
inner pressure is applied to the air bag body 12 after being turned
over.
[0030] FIG. 11 is a perspective view showing the stitched portion
with a straight line provided on the contactedly overlapped two
pieces of the base fabric material, according to the third
variation of the present embodiment.
[0031] FIG. 12 is a perspective view showing a variation of
applying tensile-force using a strap member.
[0032] FIG. 13 is an enlarged plan view showing a state in which
smaller tensile-force that pulls the pair of the faces in the
longitudinal direction is applied onto the faces so that the pair
of the faces becomes apart from each other and opened.
[0033] FIG. 14A is a partial perspective view showing a state in
which gas is discharged from the vent hole while the air bag is
inflated and expanded.
[0034] FIG. 14B is a transparent side view of the vent hole of the
air bag body being closed while the air bag body of FIG. 4 is
expanded.
[0035] FIG. 15 is a view for explaining a variation of the pair of
the faces in an asymmetrical shape.
[0036] FIG. 16 is a transparent side view of the vent hole of the
air bag body being closed while the air bag body of FIG. 15 is
expanded.
[0037] FIG. 17A is a schematic perspective view showing a state in
which the air bag system for a vehicle is applied to a driver's
seat, and the air bag body is inflated and expanded, according to
another embodiment of the present invention.
[0038] FIG. 17A is an enlarged perspective view showing a state in
which the air bag body is inflated and expanded.
[0039] FIG. 18A is a plan view showing how the plural base fabric
material of the air bag body of FIG. 17 is stitched.
[0040] FIG. 18B is a plan view showing a state in which the
stitched air bag body is turned over with the front side out.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0041] Hereinafter, detailed descriptions will be provided on an
embodiment of the present invention. FIG. 1 is a schematic
perspective view of an air bag system for a vehicle according to
one of preferred embodiments of the present invention, which is
installed to a front passenger seat where the air bag body is
inflated and expanded, FIG. 2 is a side view of FIG. 1, and FIG. 3
is a perspective view showing the air bag body that is inflated and
expanded.
[0042] As shown in FIG. 1, the air bag system for a vehicle 10
(hereinafter referred to only as "the air bag system 10" in this
specification) according to the embodiment of the present invention
is preferably applicable to an air bag system for a front passenger
seat, but not limited to this, and may be applicable to any other
air bag systems such as a side air bag system and a curtain side
air bag system (not shown).
[0043] The air bag system 10 according to this embodiment, as shown
in FIG. 2, includes the air bag body 12 made of fabric material
into a bag body shape, the inflator 14 that supplies (discharges)
gas such as nitrogen gas into the air bag body 12, the housing unit
16 in which the air bag body 12 is folded and housed, and the cover
member 20 that is integrally installed with the instrument panel 18
and seals the housing unit 16. The inflator 14 may be constituted
by a known inflator; therefore detailed descriptions thereof will
be omitted.
[0044] The air bag body 12 is a bag body made of plural base fabric
pieces stitched together, and is connected to the inflator 14 via a
gas feeding port not shown. On one side of the air bag body 12, as
shown in FIG. 1, there is provided the vent hole 22 (also referred
to as the "long slit") in a slit shape that extends in one
direction from the upper front side to the lower rear side of the
vehicle, functioning for discharging gas that has been supplied in
the air bag body 12. The vent hole 22 may be provided on either
side or both sides of the air bag body 12.
[0045] As shown in FIG. 3, on each longitudinal end of the
slit-like vent hole 22, there is provided a pinched section 24
(also referred to as a "bend section") that applies tensile-force X
in the direction apart from each other (i.e. opposing direction
from each other) in the longitudinal direction of the vent hole 22,
functioning as the tensile-force applying section (also referred to
as the "tensile-force applying means"). This pinched section 24 is
formed by overlapping two base fabric pieces 26a, 26b in contact
with each other at their side ends with a predetermined width, and
stitching the contactedly overlapped side ends together in curve
toward the edge of the base fabric pieces, as shown in broken lines
of FIG. 5A.
[0046] Specifically, with reference to FIG. 4, the two base fabric
pieces 26a, 26b of the plural base fabric pieces that constitute
the air bag body 12 in a bag body are folded at their side ends 28
toward the inside of the air bag body 12 so as to form a pair of
symmetric faces 30a, 30b, looking like long webs (rectangle). Next,
the contactedly overlapped side ends (also referred to as the
"flow-passage restriction membrane") of the faces 30a, 30b in pair
are stitched together in straight lines along the longitudinal
direction of the faces 30a, 30b so as to form a pair of the
straight stitched lines 32, 32 and also stitched continuously from
the straight stitched lines 32, 32 along a curve line to the edges
of the base fabric pieces 26a, 26b so as to form a pair of the
curved stitched lines 34, 34 (the "neck portion" is defined by the
curved stitched lines 34, 34).
[0047] The curved stitched lines 34 are provided at the
longitudinal ends of the faces 30a, 30b in pair, each apart from
the other at a predetermined distance therebetween, looking like a
bottle-neck shape in a side view. Between the pair of the curved
stitched lines 34, 34 in a bottle neck shape, there is provided a
non-stitched portion where the curved stitched lines 34, 34 are not
joined by stitching. When the gas filling the air bag body 12 is
discharged from this non-stitched portion, the faces 30a, 30b in
pair come apart from each other and are opened, so as to form the
vent hole 22. Note that the faces 30a, 30b in pair stay not outside
but inside the air bag body 12, facing the space therewithin, after
the stitched air bag body is turned over with the front side
out.
[0048] There is provided the pinched section 24 at each
longitudinal end of the slit-like vent hole 22, thereby to set the
circumferential length L1 of the air bag body 12 passing through
the longitudinal end of the bend hole 22 to be shorter than the
circumferential length L2 extending outer side from the bend hole
22 in the longitudinal direction (L1<L2), as shown in FIG.
3.
[0049] FIG. 5A is a plan view simplifying the stitched portion of
FIG. 4, and FIG. 5B is a transparent view showing a state in which
inner pressure is applied by the filling gas after turning over the
bag body 12 front side out after stitching is completed.
[0050] As shown in FIG. 5A, the contactedly overlapped side ends of
the two base fabric pieces 26a, 26b are stitched with thread, as
shown in the broken lines, so as to form the stitched line
constituted by the straight stitched line 32 and the curved
stitched line 34. In FIGS. 5A, the point A(A') represents the
longitudinal end of the vent hole 22, the point C(C') represents
the terminal point of the straight stitched line 32, and the point
B(B') represents an arbitrary point between the point A(A') and the
point C(C') on the curved stitched line 34. After the air bag body
12 is stitched in the above manner, and is turned over with the
front side out at the boundary of the stitched line, inner pressure
is applied by the filling gas into the air bag body 12 from the
inflator 14, so that the contactedly overlapped side ends of the
contactedly overlapped faces 30a, 30b in pair, functioning as the
flow-passage restriction membrane, are stretched at the point B(B')
by the tensile-force X (see the bold arrows X) acting in the
direction apart from each other so that the slit-like vent hole 22
is closed. Note that at the time of stitching the air bag body 12
shown in FIG. 5A, the stitching is carried out with the back side
of the finished air bag body 12 of FIG. 5B outside. Stitching is
carried out in the same manner in FIGS. 7A and 7B described
later.
[0051] Specially, due to the shape restriction effect of triangle
formed by the points A(A'), B(B'), C(C') as shown in FIG. 5B, the
distance D1 between the points A (A') and C(C') is maintained at a
constant distance, respectively, so that the point B(B') remains
inner side of the air bag body 12 from the point C(C'). Hence, the
circumferential length L1 passing through the point B(B') becomes
shorter than the circumferential length L2 disposed outer side from
the vent hole 22 in the longitudinal direction (L1<L2). The
portion between the points B and B' is slightly extensible (see the
broken line of FIG. 5B) so that membrane stress is concentrated,
thus the faces 30a, 30b in pair are closed to cause sealing
effect.
[0052] The form of the stitched line of the air bag body 12 is not
limited to FIG. 4. Hereinafter, variations of the stitched lines
will be exemplified.
[0053] Note that the "stitched section" denotes the entire
components that constitute the air bag body 12 by stitching at
least two pieces of the plural base fabric pieces, and includes the
stitched portion, non-stitched portion, the stitched lines in each
shape, the vent hole, and the pair of the faces as well as other
components accompanied by those components.
<Variation 1>
[0054] FIG. 6 is a perspective view of a stitched line according to
the variation 1, FIG. 7A is a plan view simplifying the stitched
line of FIG. 6, and the FIG. 7B is a transparent view showing a
state in which inner pressure is applied by the filling gas after
the stitched air bag body 12 is turned over with the front side
out.
[0055] As shown in FIG. 6, a pair of the L-shape stitched lines 36,
36 (the "neck portion" is defined by the pair of the L-shape
stitched lines 36, 36), bent in an approximate L-shape, are formed
on the side ends 28 (also referred to as the "contactedly
overlapped side ends") of the two base fabric pieces 26a, 26b with
a predetermined distance therebetween, which defines a slit-like
vent hole 22 therebetween.
[0056] In FIG. 7A, the point A(A') represents the longitudinal end
of the vent hole 22, the point B(B') represents the terminal point
of the straight stitched line 32, and the point C(C') represents an
arbitrary point on the straight stitched line 32, at an appropriate
distance from the point B(B').
[0057] After the air bag body 12 stitched along the pair of the
L-shape stitched line, as shown in FIG. 7A, is turned over with the
front side out, inner pressure is applied by the filling gas in the
air bag body 12 from the inflator 14, so that the contactedly
overlapped side ends of the faces 30a, 30b in pair, functioning as
the flow-passage restriction membrane, are stretched at the point
B(B') by the tensile-force X (see the bold arrows X) acting in the
direction apart from each other so that the slit-like vent hole 22
is closed, as shown in FIG. 7B.
[0058] Specially, due to the shape restriction effect of triangle
formed by the points A (A'), B (B') and C (C') of the L-shape
stitched line 36, the distance D1 between the points A (A') and
C(C'), and the distance D2 between the points A and A' (also see
the distance D2 of FIG. 7A) are maintained at a constant distance,
respectively, so that the point A (A') tends to move toward the
outside of the air bag body 12, but its movement is restricted by
the point C(C') so that the point A(A') remains in the inner side
of the air bag body 12 from the point B (B'). Hence, the
circumferential length L1 passing through the point A (A') becomes
shorter than the circumferential length L2 disposed outer side from
the vent hole 22 in the longitudinal direction (L1<L2). The
circumferential length of the portion between the points B and B'
is slightly extensible (see the broken line of FIG. 7B) so that
membrane stress is concentrated, thus the faces 30a, 30b in pair
are closed to cause sealing effect.
<Variation 2>
[0059] FIG. 8 is a transparent view showing the stitched line
according to the variation 2, FIG. 9A is a plan view simplifying
the stitched line of FIG. 8, and the FIG. 9B is a transparent view
showing a state in which inner pressure is applied by the filling
gas after the stitched air bag body 12 is turned over with the
front side out, and FIG. 10A is a perspective view showing a state
in which the stitched air bag body 12 of FIG. 9A is turned over
with the front side out, and FIG. 10B is a perspective view showing
a state in which inner pressure is applied to the air bag body 12
after being turned over.
[0060] As shown in FIG. 8, a pair of the V-shape stitched lines 37,
37 (the "neck portion" is defined by the pair of the V-shape
stitched lines 37, 37), bent in a sharply angled V-shape, are
formed on the side ends 28 (also referred to as the "contactedly
overlapped side ends") of the two base fabric pieces 26a, 26b with
a predetermined distance therebetween, and the V-shape stitched
lines 37, 37 define a slit-like vent hole 22 therebetween.
[0061] As shown in FIG. 8 and FIG. 9A, each V-shape stitched line
37 includes the first portion 37a extending approximately parallel
to the edge line of the side end 28, the second portion 37b
inclining from the terminal point of the first portion 37a toward
the outer side (the direction to the folding line of the
contactedly overlapped side end) of the air bag body 12 when turned
over with the front side out, and the third portion 37c sharply
bent from the terminal point of the second portion 37b toward the
side end 28 side.
[0062] In FIG. 9A, the point A(A') represents the longitudinal end
of the vent hole 22, the point B(B') represents the terminal point
of the second portion 37b, and the point C(C') represents the
terminal point of the first portion 37a.
[0063] After the air bag body 12 stitched along the pair of the
V-shape stitched lines is turned over with the front side out, as
shown in FIG. 9A, when inner pressure is applied by the filling gas
into the air bag body 12 from the inflator 14, the point B(B') is
located on the inner side and the point C(C') is located on the
outer side of the air bag body 12 because the circumferential
length L1 passing through the point B(B') is set to be shorter than
the circumferential length L2 passing through the point C(C'), as
shown in FIG. 9B.
[0064] Specially, due to the shape restriction effect of triangle
formed by the points A (A'), B (B') and C (C') of the V-shape
stitched line 37, the distance D1 between the points A (A') and
C(C') and the distance D2 between the points B and B' are
maintained at a constant distance, respectively, so that the point
A (A') moves from the inner side toward the outer side of the air
bag body 12, and the movement of the point B(B') is restricted and
remains inside the air bag body 12, and the tensile-force X (see
the bold arrows X) is generated on the point B(B') in the direction
apart from each other so that the vent hole 22 is closed.
[0065] In a state of FIG. 10A, in which the air bag body 12
stitched along the V-shape stitched lines 37 is turned over with
the front side out but no inner pressure is applied, the point
A(A') stays within the air bag body 12. In a state of FIG. 10B, in
which the stitched air bag body 12 is turned over with the front
side out and inner pressure is applied in the air bag body 12, the
point A(A') protrudes toward the outer side of the air bag body 12
and gets exposed outside.
<Variation 3>
[0066] FIG. 11 is a perspective view of the stitched line according
to the third variation. Without folding the side ends 28 of the
pair of the base fabric pieces 26a, 26b, on its contactedly
overlapped side ends of the air bag body 12, a pair of the straight
stitched lines 32, 32 are provided at a predetermined distance
therebetween, which forms a slit-like vent hole 22
therebetween.
[0067] The above-mentioned pair of the stitched lines 32, 32 on the
side ends along the longitudinal direction of the slit-like vent
hole 22 may be in various shapes, serving as an end-support to
support both the side ends of the faces 30a, 30b in pairs. This
pair of the stitched lines securely fix the faces 30a, 30b in pair
to come in contact with each other, so as to provide sealing
effect. In addition, the air bag body 12 is constituted by plural
base fabric pieces, and at least two base fabric pieces 26a, 26b of
the plural base fabric pieces are stitched, where the vent hole 22
is provided. Accordingly, this can facilitate manufacturing of the
air bag body 12 and mass-production can be realized.
[0068] Furthermore, as a means of applying the predetermined
tensile-force onto the vent hole 22, other than the above-mentioned
stitched lines on the two contactedly overlapped base fabric pieces
26a, 26b, a pair of straps 33, 33 (also referred to as a "strap
member") provided in the vicinity of the both longitudinal ends of
the vent hole 22 may be used, thereby to reduce the circumferential
length L1 of the air bag body 12, passing through these
longitudinal ends of the vent hole 22. Each end of the strap 33 is
fixed to the air bag body 12 by the stitched portion 35. The strap
33 facilitates applying of a predetermined tensile-force onto the
vent hole 22. Note that the strap 33 may be provided on either end
of the vent hole 22.
[0069] The air bag system 10 according to this embodiment is
basically constituted as mentioned above, and hereinafter
operational effects of the system 10 will be provided.
[0070] First, normal effects of the inflation and expansion when
the air bag body 12 does not come in contact with an obstacle
M.
[0071] At the time of a vehicle collision, the inflator 14 starts
to operate in response to control signals sent from the controller
(not shown), and the inflator 14 injects gas into the air bag body
12, thereby to open the cover member 20 installed on the instrument
panel 18.
[0072] The gas supplied from the inflator 14 via the gas inflow
port (not shown) pushes the inner wall of the air bag body 12, so
that the air bag body 12 becomes inflated and expanded toward the
front passenger seat side, as shown in FIG. 1. Then, the inflated
and expanded air bag body 12 comes in contact with and presses an
occupant (not shown) and restricts his or her movement so as to be
protected.
[0073] When the air bag body 12 becomes inflated and expanded by
gas supplied into the air bag body 12, suppress strength pushing
the inner wall of the air bag body 12 toward the outer side is
generated due to surface pressure of the gas pressure, and then
this suppress strength generates the tensile-force X that pulls
both the longitudinal ends of the slit-like vent hole 22 apart from
each other in the longitudinal direction (opposite direction) of
the vent hole 22.
[0074] This tensile-force X causes the faces 30a, 30b in pair
around the slit-like vent hole 22 to be closed, and the contact
between the faces 30a, 30b is maintained so that sealing effect
works. Since the faces 30a, 30b are closed, the vent hole 22 is
also closed, thereby to reduce gas leakage from the vent hole
22.
[0075] Specifically, the tensile-force applying section
(tensile-force applying means) is set in such a manner that there
are provided the pinched sections on both the longitudinal end
sides of the slit-like vent hole 22, so as to provide difference in
the circumferential length between around both the longitudinal
ends of the slit-like vent hole 22 (L1) and around the outer side
from the vent hole 22 (L2). Whereby, membrane stress
(tensile-force) shown in the bold arrow X of FIG. 3 is applied onto
the vent hole 22 from each side end of the vent hole 22 having a
shorter circumferential length (L1) toward the outer side having a
longer circumferential length (L2), due to gas pressure pushing
from the inner wall side of the air bag body 12.
[0076] This tensile-force X is applied onto the faces 30a, 30b in
pair constituting of the vent hole 22, so that the vent hole 22
constituted by the faces 30a, 30b becomes almost completely closed,
causing sealing effects.
[0077] Note that surface pressure of the gas pressure in the air
bag body 12 pushes the contactedly overlapped side ends of the
faces 30a, 30b in pair facing the inner wall side of the air bag
body 12, and the combination of this pushing force onto the faces
30a, 30b in contact with each other and the tensile-force X that
pulls the vent hole 22 in the above direction further enhances
sealing effects.
[0078] According to the present embodiment, the above-mentioned
seal effects almost completely seal the vent hole 22 so that gas
leakage from the vent hole 22 can be significantly reduced, thus
this embodiment reduces gas leakage to the external, which is a
problem of a conventional technique, thereby to enhance gas
charging efficiency.
[0079] Next, descriptions will be provided on a case in which the
air bag body 12 comes in contact with and presses the obstacle M
during its inflation and expansion.
[0080] As shown in FIG. 2, when the air bag body 12 comes in
contact with and presses the obstacle M, the air bag body 12 gets
deformed by the obstacle M, and this deformation reduces the
tensile-force X that pulls the vent hole 22 at both the
longitudinal ends apart from each other. As the tensile-force X is
reduced, the force F to open the slit-like vent hole 22 in the
vertical direction to the longitudinal direction of the vent hole
22 eventually exceeds the tensile-force X, so that the faces 30a,
30b in pair come apart and opened, whereby the vent hole 22 opens,
too (see FIGS. 13 to 14B).
[0081] Specifically, the slit-like vent hole 22 is formed to extend
along one direction from the upper front side to the lower rear
side of the vehicle, the direction to reduce the inflation and
expansion force of the air bag body 12. Therefore, when the air bag
body 12 during its inflation and expansion comes in contact with
and presses the obstacle M located in the vent hole's extending
direction, the tensile-force X, which pulls the faces 30a 30b in
pair apart from each other along the longitudinal direction of the
vent hole 22, is unstrained and becomes smaller compared to that
during the inflation and expansion before coming in contact with
the obstacle M.
[0082] In other words, since the vent hole 22 is formed as a long
slit along the direction in which the air bag body's 12 expansion
is restricted, when the air bag body 12 during its inflation and
expansion comes in contact with and presses an obstacle M located
along the direction to restrict the expansion of the air bag body
12, the tensile-force X, which pulls the each longitudinal end of
the faces 30a 30b in pair apart from each other along the
longitudinal direction of the vent hole 22, is unstrained and
becomes smaller than the tensile-force X during the inflation and
expansion before coming in contact with the obstacle M.
[0083] Accordingly, the faces 30a, 30b in pair constituting the
vent hole 22 become apart from each other, being pushed by the gas
pressure of the gas filling the air bag body 12 because the
tensile-force X becomes unstrained (smaller), and then get apart
enough from each other to form a relatively wide opening 38 (see
FIG. 13). As a result, by releasing the filling gas from the wide
opening 38 of the vent hole 22, energy (load) applied through the
air bag body 12 onto the obstacle M can be reduced, so that
excessive energy applied onto the obstacle M can be preferably
prevented.
[0084] Specifically, the direction where the tensile-force X is
applied to the vent hole 22 is set to be in accordance with the
direction where the air bag body 12 comes in contact with the
obstacle M; thus, when the air bag body 12 during its inflation and
expansion comes in contact with and presses the obstacle M, the
tensile-force X, pulling the slit-like vent hole 22 at both the
longitudinal ends of the faces 30a, 30b apart from each other in
the longitudinal direction, becomes eased, and the faces 20a, 30b
in pair get apart from each other and the slit-like vent hole 22 is
widely opened, thus the gas filling the air bag body 12 is
preferably discharged from the vent hole 22. As mentioned above,
the present embodiment provides a proper regulation of discharging
rate of the gas filling the air bag body 12 from the vent hole 22
through the faces 30a, 30b in pair, depending on the inflation and
expansion states of the air bag body 12; a normal
inflation/expansion state in which the air bag body 12 is out of
contact with the obstacle M during its inflation and expansion, or
a state in which the air bag body 12 comes in contact with and
presses the obstacle M during its inflation and expansion.
[0085] Next, variations of the faces 40a, 40b in pair will be
described hereinafter, with reference to FIGS. 15 and 16.
[0086] FIG. 15 is a perspective view of one variation of the faces
40a, 40b in pair in an asymmetric manner, and FIG. 16 is a
transparent view, seen from the lateral direction, of a state in
which the vent hole 22 is closed when the air bag body 12 having
the faces 40a, 40b in pair is expanded.
[0087] Contrary to the faces 30a, 30b in pair shown in FIGS. 4, 6,
8, both made in a symmetrical shape; the faces 40a, 40b in pair
according to this variation are each made asymmetrical, such that
the face 40a is formed in a trapezoidal shape and the face 40b is
formed in a long rectangular shape.
[0088] At this time, the face 40a has a triangular portion 42 which
is not contactedly overlapped with the rectangular face 40b, and
this non-overlapped triangular portion 42 works as drag against gas
outflow, so as to restrict the gas discharge rate from the
slit-like vent hole 22 depending on the open degree of the vent
hole 22. This makes the gas discharge rate during the inflation and
expansion of the air bag body 12 approximately linear, thereby to
provide advantage in moderating the gas discharge from the vent
hole 22.
[0089] In this variation, the non-overlapped portion is exemplified
to be the rectangular portion 42, but is not limited to this shape
as far as the face 40a and the face 40b are made asymmetrical.
[0090] FIGS. 17 and 18 show another embodiment of the present
invention, in which the air bag system 10a may be installed to a
driver's seat. Note that the same numerical references are used for
the same components, and detailed descriptions will be omitted.
[0091] FIG. 17A is a schematic perspective view showing a state in
which the air bag body 12 is inflated and expanded at a driver's
seat, FIG. 17B is an enlarged perspective view of the air bag body
12 inflated and expanded. FIG. 18A is a plan view showing a state
in which the plural base fabric pieces are stitched, and also
showing a positional relation between the outer circumference and
the inner circumference of the air bag body 12 when inflated and
expanded, and FIG. 18B is a plan view showing a state in which the
stitched air bag body 12 is turned over with the front side
out.
[0092] As shown in FIGS. 17A to 18B, in its inflation and expansion
state, the air bag body 12 is formed such that the circumferential
length L1 passing through the longitudinal end of the vent hole 22
is locally reduced so as to be shorter than the circumferential
length L2 extending outer side from the bend hole 22 in the
longitudinal direction (L1<L2). As mentioned above, the air bag
system 10a may be applied to the driver's seat, thereby to enhance
general purpose property, and realize reduction of size and
weight.
[0093] Other structures, component and or operational effects are
the same as those of the above embodiment, thus the detailed
descriptions will be omitted.
[0094] As mentioned above in details, the present invention
provides an air bag system for a vehicle including an air bag body
constituted by stitching plural base fabric pieces; an inflator
that supplies gas into the air bag body; a vent hole which is a
through hole provided in the air bag body so as to communicate the
inside with the outside of the air bag body. In this air bag system
for a vehicle, the vent hole is formed to be long in one direction,
and there are provided a tensile-force applying means that applies
tensile-force along the longitudinal direction of the vent hole,
and a pair of faces along the gas injection port of the vent hole,
and this pair of the faces function as a flow-passage restriction
membrane.
[0095] Therefore, according to the present invention, in a normal
inflation/expansion state in which there is no obstacle in the
inflation and expansion direction of the air bag body, the
tensile-force applying means applies a predetermined tensile-force
onto the pair of the faces, so that the faces function as the
flow-passage restriction membrane and cause a sealing effect,
thereby to reduce gas leakage from the vent hole. Accordingly, it
is possible to inflate and expand the air bag body with the vent
hole closed, as well as maintaining gas pressure in the air bag
body at a constant rate.
[0096] On the other hand, if there is an obstacle in the expanding
direction of the air bag body, and when the air bag body comes in
contact with and presses this obstacle, smaller tensile-force is
applied by the tensile-force applying means, compared to the
tensile-force in the normal inflation/expansion state, so that the
pair of the faces working as the flow-passage restriction membrane
get apart from each other to form a wide opening, through which the
gas is discharged. Accordingly, if the air bag body comes in
contact with and presses an obstacle or the like during its
inflation and expansion, the gas filling the air bag body is
allowed to flow out through the vent hole to the outside, so as to
reduce load (energy) applied onto the obstacle, thereby to properly
prevent excessive energy from being applied onto the obstacle or
the like.
[0097] In the present invention, the air bag body is constituted by
plural basic fabric pieces, the air bag body further includes a
stitched section where at least two pieces of the plural basic
fabric pieces are stitched. The vent hole is provided in the
stitched section, and the stitched section includes a neck portion
that is set in the direction from the outside toward the inside of
the air bag body so that, when the air bag body is inflated and
expanded, an outer circumferential length passing through a
longitudinal end of the vent hole of the air bag body is locally
reduced so as to be shorter than an outer circumferential length
extending outer side from the vent hole.
[0098] Furthermore, in the present invention, the air bag body is
constituted by plural basic fabric pieces, and includes a stitched
section where at least two pieces of the plural basic fabric pieces
are stitched, and the vent hole is provided in the stitched
section. The stitched section includes a bend section recessed in
curve toward the inside of the air bag body, so that, when the air
bag body is inflated and expanded, an outer circumferential length
passing through a longitudinal end of the vent hole of the air bag
body (L1) is locally reduced so as to be shorter than an outer
circumferential length extending outer side from the vent hole
(L2); and an end-support that supports both the contactedly
overlapped side ends of the faces, and the bend section includes
the tensile-force applying means.
[0099] According to the present invention, surface pressure
distribution of the inner wall of the air bag body, pushed by the
filling gas, may be found through an experiment or simulation in
advance, and based on results of the experiment or simulation, the
tensile-force applying means may be provided so as to apply
tensile-force onto the pair of the faces in the longitudinal
direction apart from the vent hole.
[0100] The tensile-force applying means may be a neck portion that
is set in the direction from the outside toward the inside of the
air bag body, constituted such that, when the air bag body is
inflated and expanded, the circumferential length (L1) passing
through the longitudinal end of the vent hole 22 is locally reduced
so as to be shorter than the circumferential length (L2) extending
outer side from the bend hole 22 in the longitudinal direction.
With this neck portion, predetermined tensile-force that pulls the
pair of the faces in the longitudinal direction apart from the vent
hole is generated, so that the vent hole is sealed. When the air
bag body comes in contact with and presses an obstacle during its
inflation and expansion, the membrane stress applied in the
direction to seal the pair of the faces is reduced so that the vent
hole is opened, and gas is discharged through this opened vent
hole, thereby to reduce energy (collision energy) applied onto the
obstacle.
[0101] An alternative tensile-force applying means, for example,
may be a bend section formed by stitching in a curve line the
contactedly overlapped side ends of the pair of the faces,
constituted such that, when the air bag body is inflated and
expanded, the circumferential length (L1) passing through the
longitudinal end of the vent hole 22 is locally reduced so as to be
shorter than the circumferential length (L2) extending outer side
from the bend hole 22 in the longitudinal direction. This bend
section causes predetermined tensile-force that pulls the pair of
the faces in the direction apart from the vent hole, so that the
vent hole is sealed. When the air bag body comes in contact with
and presses an obstacle during its inflation and expansion, the
membrane stress applying in the direction to seal the pair of the
faces is varied so that the vent hole is opened, and gas is
discharged through this opened vent hole, thereby to reduce energy
(collision energy) applied onto the obstacle.
[0102] Yet, another alternative tensile-force applying means, for
example, may be at least one strap member fixed in the vicinity of
at least either of the longitudinal ends of the vent hole so as to
reduce the circumferential length of the air bag body passing
through the longitudinal end. The strap member facilitates in
applying the predetermined tensile-force onto the vent hole.
[0103] The air bag body may be constituted by plural base fabric
pieces, and the vent hole may be provided on the non-stitched
portion defined by the stitched portion formed by stitching at
least two pieces of the plural base fabric pieces stitched
together, which facilitates and enables mass-production of the air
bag body. Moreover, the end-support functions for supporting both
the contactedly overlapped side ends of the pair of the faces in
the longitudinal direction, so as to securely bring the faces in
contact with each other, there by to cause sealing effect.
[0104] At this time, the present invention may provide a pair of
faces in an asymmetrical shape, which prevent burst outflow of gas
from the vent hole so as to moderate the gas outflow.
[0105] In the present invention, the pair of the faces are provided
inside of the air bag body, facing the inner space thereof, so that
the gas surface pressure pushes the pair of the faces together, and
combination of this surface pressure and the above tensile-force
greatly enhances prevention of gas leakage from the vent hole.
[0106] Yet, the present invention provides a slit-like vent hole
along the direction from the upper front side to the lower rear
side of a vehicle, so that the air bag body may cover from a
relatively larger substance at the upper front side to a relatively
smaller substance at the lower rear side of the vehicle, thereby to
prevent an excessive energy from being applied onto this
substance.
[0107] The present invention further provides an air bag system for
a vehicle including an air bag body formed in a bag form, an
inflator that charges the air bag body with gas and a vent hole
provided in the air bag body for discharging the gas filling the
air bag body.
[0108] In the above air bag system, the air bag body includes a
pair of faces that are provided around the vent hole to form the
vent hole in a slit-like shape extending in one direction, and a
tensile-force applying section that applies tensile-force onto the
pair of the faces in the longitudinal direction apart from the vent
hole. The pair of the faces becomes closed and sealed when the
tensile-force applying section applies a predetermined
tensile-force onto the pair of the faces, and the pair of the faces
becomes apart from each other and opened when the tensile-force
applying section applies smaller tensile-force than the
predetermined tensile-force onto the pair of the faces, so that the
gas filling the air bag body is discharged from the opening of the
pair of the faces.
[0109] According to the present invention, in the normal
inflation/expansion state in which there is no obstacle in the
expansion direction of the air bag body, the tensile-force applying
section applies the predetermined tensile-force onto the pair of
the faces so as to be almost completely sealed, thereby reduce gas
leakage from the vent hole. Therefore, it is possible to inflate
and expand the air bag body with the vent hole almost completely
sealed while maintaining the gas pressure in the air bag body at a
constant rate.
[0110] On the other hand, if there is an obstacle in the expansion
direction of the air bag body and the air bag body comes in contact
with and presses the obstacle during its inflation and expansion,
the tensile-force applying section applies smaller tensile-force,
compared to that in the normal inflation/expansion state, so that
the pair of the faces get apart from each other to form a wide
opening, through which the filling gas is discharged. Accordingly,
since the gas filling the air bag body is allowed to be discharged
outside through the vent hole when the air bag body comes in
contact with and presses an obstacle or the like during its
inflation and expansion, it is possible to reduce load (energy)
applied onto the obstacle, thereby to prevent excessive energy from
being applied onto the obstacle.
[0111] The present invention yet further provides an air bag system
for a vehicle including an air bag formed by stitching basic fabric
material, an inflator that charges the air bag body with gas, and a
vent hole that is a through hole provided in the air bag body so as
to communicate the inside with the outside of the air bag body. In
the above air bag system, the vent hole for discharging the gas
filling the air bag body is formed in a long slit along the
direction to restrict the expansion of the air bag.
[0112] According to the present invention, if there is an obstacle
or the like in the direction where the air bag body is expanded,
that is, the direction where the expansion of the air bag body
should be restricted, and the obstacle comes in contact with and
pressed by the air bag body, the long slit becomes opened, and gas
is discharged from this opened slit, so that excessive energy can
preferably be prevented from being applied onto the obstacle or the
like.
[0113] The present invention provides an air bag system for a
vehicle, that can regulate discharge rate of the gas filling the
air bag body from the vent hole thereof when the air bag body comes
in contact with and presses an obstacle or the like during its
inflation and expansion, and also can inflate and expand the air
bag body quickly with the vent hole closed when the body does not
come in contact with the obstacle, while maintaining the gas
pressure in the air bag body at a constant rate.
[0114] The embodiments according to the present invention have been
explained as aforementioned. However, the embodiments of the
present invention are not limited to those explanations, and those
skilled in the art ascertain the essential characteristics of the
present invention and can make the various modifications and
variations to the present invention to adapt it to various usages
and conditions without departing from the spirit and scope of the
claims.
* * * * *