Land vehicles – Wheeled – Attachment
Reexamination Certificate
2001-10-25
2004-03-23
Dunn, David R. (Department: 3616)
Land vehicles
Wheeled
Attachment
C280S732000
Reexamination Certificate
active
06709005
ABSTRACT:
BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT
The present invention relates to an airbag retainer for housing an airbag for protecting a vehicle occupant and the like, and more specifically, it relates to an airbag retainer having advantages of reduced cost and weight, and so on.
Most of conventional passenger vehicles are equipped with at least one airbag assembly, such as a driver airbag, a passenger airbag and a rear-seat airbag, as well as a side airbag in order to protect passengers in the event of a vehicle collision. A typical airbag assembly is mounted in a vehicle as a module incorporating a bag, a retainer, an inflator, a cover and so on.
Regarding a passenger airbag assembly as an example, a known art of the airbag assembly will be described. FIG.
10
(A) is a side sectional view illustrating an example of a known passenger airbag assembly which is mounted on a board. FIG.
10
(B) is a plan view illustrating the interior of a retainer of the airbag assembly in FIG.
10
(A). FIG.
10
(C) is a side sectional view illustrating in further detail another known passenger airbag assembly.
An airbag assembly
100
is placed in a position so as to face a windshield F mounted above an instrument panel P of a vehicle as shown in FIG.
10
(A). The airbag assembly
100
has a retainer
110
, wherein a cover
120
, which is brought into alignment with the instrument panel P, is fixed by using cover-fixing portions
121
. With this arrangement, the retainer
110
is welded at the bottom thereof to a bracket
114
. A bag
103
and an inflator
105
for feeding gas into the bag
103
are arranged in the retainer
110
. The bag
103
is folded and housed in the retainer
110
under normal conditions.
The retainer
110
includes a box-shaped main unit ill with a bottom and flange surfaces as shown in FIGS.
10
(B) and
10
(C) for better understanding. The main unit
111
has a solid structure made of metal or resin and a plurality of fixing plates
113
, which engages the cover-fixing portions
121
, at the mouth edge of the main unit
111
. An engagement opening
110
a
for the inflator
105
is provided to open at the bottom of the main unit
111
. A bag plate
115
integrally formed of a semicircular portion
115
a
and a plurality of flange portions
115
b
is arranged in the main unit
111
. The semicircular portion
115
a
of the bag plate
115
holds the inflator
105
. Bolts
119
fix the flange portions
115
b
of the bag plate
115
to a flange surface of the retainer
110
. The end of an opening of the bag
103
is put between the flange portion
115
b
and the flange surface of the retainer
110
in a state such that the bag plate
115
is fixed to the retainer
110
.
With this airbag assembly
100
, the gas in the inflator
105
is introduced into the bag
103
in the event of a vehicle collision. Subsequently, the bag
103
breaks the cover
120
by tearing a tear line
122
thereof, and inflates in front of a passenger.
The retainer
110
of the above-described known airbag assembly
100
has the following problems because of its solid structure made of a metal or resin.
(I) Retainer Made of Metal
(1) A metal retainer is formed by deep drawing or sheet metal welding. Because of its poor formability as compared to sheet metal welding, deep drawing is unsuitable for forming a metal sheet into a complicated shape. Sheet metal welding, on the other hand, requires an increased number of manufacturing processes for welding, resulting in increased cost.
(2) Metal retainers are heavier than resin retainers.
(II) Retainer Made of Resin
(3) Attaching a fixing bracket made of metal to a main unit of a resin retainer after the main unit has been molded requires an increased cost. The main unit and the fixing bracket therefore are often formed in a single-piece manner. This single-piece structure, however, does not allow only one type of a retainer to be used for plural types of vehicles, each having a different bracket (see the bracket
114
in FIG.
10
(A) as an example). Therefore, the resin retainer requires a new metal mould for producing a whole retainer, even though the only difference between them resides in the shapes of the fixing brackets. This limits the range of usage of the resin retainer.
(4) only compressed-gas type inflators are appropriate for the resin retainers, because the portions of the retainers coming into contact with inflators may melt due to heat generated when the inflators are ignited.
(5) Two types of inflators are available, i.e. a compressed gas type and a combustion gas type, and an appropriate one is chosen. In the meantime, as to the inflator of the compressed gas type, little change in temperature occurs in the inflator body upon activation, as compared to that of the combustion type. Because of the reason as mentioned in (4), an inflator of the compressed gas type is usually an only choice.
(6) A resin retainer requires a thicker plate than a metal retainer does in order to obtain the same strength. Specifically, the thickness of a resin plate must be three times or more greater than that of a metal plate while the thickness of about 1 mm is sufficient for the metal plate, thereby rendering it difficult to downsize the resin retainer.
In view of the above-described problems, the object of the present invention is to provide an airbag retainer having advantages of reduced cost, weight, and size.
Further objects and advantages of the invention will be apparent from the following description of the invention
SUMMARY OF THE INVENTION
To solve the above-described problems, an airbag retainer of the present invention, for housing and holding an airbag which inflates in an emergency and an inflator which supplies gas for inflating the airbag, comprises a bag-housing member (an upper portion: an upper retainer) made of a resin, and an inflator-holding member (a lower portion: a lower retainer) made of metal.
The airbag retainer according to the present invention has an improved formability, and can achieve the reduced production cost and weight, as compared to a solid metal retainer. When comparing with a solid resin retainer, because of the increased heat endurance strength of the inflator-holding member, an inflator in a wider range of types is available for the airbag retainer. In addition, the above increased strength permits the inflator-holding member to reduce its thickness, accordingly allowing the retainer to reduce its height.
When the airbag retainer of the present invention is applied to a plurality of different types of vehicles, the only thing to do is to choose a usable bracket, which is to be spot-welded to the lower retainer, according to a vehicle type. This renders the airbag retainer suitable for a wider range of uses. Welding the bracket to the lower retainer is a known fixing art as has been used for conventional retainers.
According to the airbag retainer of the present invention, the upper retainer may have a frame-shaped structure provided with sidewalls on the four sides thereof, and the lower retainer may have sidewalls on a pair of opposing sides among its four sides, such that the sidewalls of the lower retainer partly overlap the corresponding sidewalls of the upper retainer.
This structure serves to enhance the strength against an expansive force of the inflating bag, thereby to prevent a fish-mouth deformation of the retainer. The fish-mouth deformation means a state in which the central portions of the sidewalls of the lower retainer are deformed outward upon receiving the expansive force of the inflating bag.
Also, according to the airbag retainer of the present invention, the upper retainer and the lower retainer may have a plurality of fastening portions. At least one of the plurality of fastening portions is preferably broken or stretched when a load is applied to an instrument panel of an automobile.
Further, according to the airbag retainer of the present invention, a plurality of flange-shaped fastening portions of each of the upper retainer and the lower retainer is preferable arranged to have surface-to
Dunn David R.
Kanesaka & Takeuchi
Takata Corporation
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