Land vehicles – Wheeled – Occupant propelled type
Reexamination Certificate
2002-03-12
2004-01-13
Dickson, Paul N. (Department: 3616)
Land vehicles
Wheeled
Occupant propelled type
C280S742000
Reexamination Certificate
active
06676147
ABSTRACT:
TECHNICAL FIELD
This invention relates to an airbag device, which is a protecting device for a seat occupant of a vehicle or the like.
BACKGROUND ART
An airbag device is, in general, composed of a casing arranged at the front part in the indoor room of a vehicle such as an instrument panel or a center of a steering wheel, an airbag housed in the casing in a folded fashion, and an inflator as a gas generator and constructed so that the airbag may be expanded and deployed toward the occupant by the gas the inflator generates upon impingement of the vehicle, thereby receiving the occupant's body.
With the recent demand of a more lightweight vehicle, the airbag device is required to be compactified. The more compactified the casing, however, the more difficult becomes the work of assembling the airbag in the casing. In particular, with a conventional typical airbag device, a rectangular lip portion of the airbag is fixed to the inside wall of the opening marginal portion of the casing with a bag retainer, etc. and hence, the smaller the open area of the casing is made, the more difficult the work of fixing the airbag to the casing.
Conventional airbag devices are classified, according to the way of arrangement of housing the inflator and airbag in the casing, into a series arrangement type as shown in
FIG. 13 and a
parallel arrangement type as shown in FIG.
14
.
In the series arrangement type of airbag device as illustrated in
FIG. 13
, in a casing
101
opening upwards there are housed and disposed a columnar inflator
102
at its bottom side and an airbag
103
, at its upper opening side. Since the airbag
103
and the inflator
102
are arranged upwards and downwards, it is possible to make the opening area of the casing
101
small, but the entirety of the airbag
103
is forced out by the gas given off from the inflator
102
and yet controlling its deployment behavior is not easy.
According to the parallel arrangement type of airbag device shown in
FIG. 14
, in the casing
101
opening upwardly, the columnar inflator
102
is arranged at the frontward side of the vehicle, namely counter-occupant side whereas the airbag
103
is housed at the rearward side of the vehicle, namely the occupant side. In this case, the inflator
102
and the airbag
103
are arranged fore and aft, so that it is possible to deploy the airbag from its upper side by the gas generated from the inflator
102
. However, a door covering the opening of the casing
101
is indispensably large because of a large opening area of the casing
101
and thus there are many restrictions in mounting on the vehicle.
Another arrangement type of one is also proposed as shown in
FIG. 15
, wherein the casing
101
opening upwardly is provided, at its central part relative to the fore-and-aft direction, with a concave portion
104
on which to dispose the inflator
102
, a diffuser
105
is provided so as to cover the inflator
102
arranged within the concave portion
104
, and the airbag
103
is folded and accommodated fore and aft relative to the diffuser
105
. With this type, because the inflator
102
is arranged in the center, it is difficult to control the deployment behavior of the airbag
103
and besides owing to a large opening area of the casing
101
the door covering the opening is also large, which causes many restrictions in mounting on the vehicle.
Aside from above, another type of airbag device is also known in the art, which is constructed so that a diffuser for adjusting and regulating the gas flows generated by the inflator is formed in a cylindrical form to surround the outer circumference of the inflator in order to facilitate the work of securing the airbag to the casing and arranged within the lip portion of the airbag thereby to engage the airbag with the diffuser within the casing.
FIG. 16
is a sectional view of a prior art airbag device of this kind. In a casing
201
, a generally columnar inflator
202
and a folded airbag
203
are accommodated. The inflator
202
is loaded in a columnar diffuser
204
and locked through a cap
205
to the one of opposed sidewalls of the casing
201
by means of a bolt
206
and nut
207
. The airbag
203
is attached at its lip portion
208
to wrap the outer circumference of the diffuser
204
, thereby being engaged within the casing
201
. The airbag
203
has right-hand and left-hand openings whose marginal portions
209
,
210
are pinched in clearances X between the edges of the diffuser
204
and the sidewalls of the casing
201
, which are in turn made small by the locking of the inflator
202
with the aid of the bolt
206
and nut
207
to prevent the gas from leaking.
With the construction shown in
FIG. 16
, however, the gas from a gas blowoff part
211
provided at one end of the inflator
202
is directly blown to the clearance X, so that it is difficult to avoid firmly the gas leakage.
FIG. 17
is a sectional view showing another known airbag device of this kind. Here, the opening marginal portions
209
,
210
of the airbag
203
are not pinched in the clearances X between the diffuser
204
and the sidewalls of the casing
201
, but the clearances X are closed by pressing the edge of the diffuser
204
with the cap
205
.
However also in this construction shown in
FIG. 17
, the gas is likely to leak as a result of deformation of the end of the diffuser
204
owing to a gas pressure from the gas blowoff part
211
. Furthermore since the opening marginal portion
209
of the airbag
203
is not pinched, the gas is likely to leak also from a clearance between the opening margin
209
and the perimeter of the diffuser
204
.
In view of the prior art problems and difficulties described above, this invention has been made and therefore a first object of this invention is to provide an airbag device, with which it is easy to control the deployment behavior of the airbag and which is superior in workability in assembling the airbag in the casing.
A second object of this invention is to prevent the inflator gas from leaking outside, in an airbag device such that the airbag is engaged within the casing with a cylindrical member such as a diffuser in order to improve the workability of assembling the airbag in the casing.
DISCLOSURE OF INVENTION
A first invention for solving the first object is an airbag device comprising a casing having an opening, a generally columnar inflator housed in the casing at its bottom side, an airbag folded and housed in the casing at its opening side and a cylindrical member surrounding the outer periphery of the inflator and having at its peripheral surface holes for blowing off gas emitted by the inflator, wherein the cylindrical member is provided with a partition wall projecting toward the opening side of the casing to compart the space for housing therein the airbag into two sides, the airbag is divided and housed in the one side and the other side of the partition wall, the airbag has a lip portion extending to the bottom part of the cylindrical member so that the outer periphery of the cylindrical member is surrounded by the airbag, the bottom part of the cylindrical member is locked to the bottom surface of the casing to form a locked part, with which the lip portion of the airbag is engaged to fix the airbag to the casing.
According to this airbag device, the bottom part of the cylindrical member is locked to the bottom surface of the casing in the state that the cylindrical member is arranged inside the lip portion of the airbag, whereby it is possible to fix the airbag on the bottom surface of the casing. Consequently, the airbag device is excellent in the workability of assembling the airbag and the cylindrical member in the casing and advantageous particularly in case where the opening area of the casing is small.
This airbag device falls under a series arrangement type wherein the airbag and the inflator are arranged upwards and downwards in the casing, and hence the opening area of the casing can be made small. Moreover the diffuser for controlling the gas flow to the airbag is provided wit
Bito Kazuaki
Mihara Yoshinori
Ozaki Toru
Sasaki Takashi
Shibayama Kenji
Dickson Paul N.
Fleming Faye
Knobbe Martens Olson & Bear LLP
Toyoda Gosei Co,., Ltd.
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