Land vehicles – Wheeled – Attachment
Reexamination Certificate
2000-07-20
2002-04-02
Dickson, Paul N. (Department: 3611)
Land vehicles
Wheeled
Attachment
C280S741000
Reexamination Certificate
active
06364354
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an air bag system which can effectively restrain an occupant, and more particularly to a gas generator including two or more combustion chambers, two igniters, two different gas generating means, an igniter having a lead wire, a combustion chamber, ignition means provided in an inner cylindrical member, and an automatic ignition material.
BACKGROUND OF THE INVENTION
An air bag system, which is mounted on various kinds of vehicles and the like including automobiles, aims to hold an occupant of the vehicle by means of an air bag (a bag body). The air bag is rapidly inflated by a gas when the vehicle collides at a high speed so as to prevent the occupant from crashing into a hard object inside the vehicle, such as a steering wheel and windscreen, due to an inertia and from being injured. This kind of air bag system generally comprises a gas generator actuated according to a collision of the vehicle and discharge a gas, in order to introduce the gas into the air bag to inflate the air bag.
It is desired that the air bag system of this type can safely restrain the occupant even when frame of the occupant (for example, whether a sitting height of the occupant is long or short, whether the occupant is an adult or a child, and the like), a sitting attitude (for example, an attitude of the occupant holding the steering wheel) and the like are different. Then, there has been conventionally suggested an air bag system which actuates by applying as small as possible impact to the occupant at the initial stage of the actuation. Gas generators in such a system are disclosed in JP-A 8-207696, U.S. Pat. Nos. 4,998,751, and 4,950,458. JP-A 8-207696 suggests a gas generator, in which one igniter ignites two kinds of gas generating agent capsules so as to generate the gas in two stages. U.S. Pat. Nos. A4,998,751 and 4,950,458 suggest a gas generator, in which two combustion chambers are provided for controlling actuation of the gas generator so as to generate the gas in two stages due to an expanded flame of the gas generating agent.
However, these gas generators have drawbacks in that an internal structure thereof is complicated, a size of a container is large, and a cost therefor becomes expensive.
Further, in JP-A 9-183359 and DE-B 19620758, there is disclosed a gas generator, in which two combustion chambers, each storing a gas generating agent, are provided in a housing and an igniter is arranged in each combustion chamber, so as to adjust an activation timing of each of the igniters, thereby adjusting an output of the gas generator. However, in the above gas generators, since the igniters arranged in the respective combustion chambers are independently arranged, it becomes difficult to assemble (manufacture), the structure itself of the gas generator becomes complicated and a volume thereof becomes large.
SUMMARY OF THE INVENTION
In order to solve the above-problems, the present invention provides a gas generator which actuates while applying as small an impact as possible to an occupant at the initial stage of an operation and can widely and selectively adjust an output and timing of an output increase of the gas generator so as to safely restrain the occupant even when frame of the occupant (for example, whether a sitting height of the occupant is long or short, whether the occupant is an adult or a child, and the like), a sitting attitude (for example, an attitude of the occupant holding the steering wheel) and the like are different, as well as restricting the total size of a container, providing a simple structure and that can be easily manufactured.
A gas generator for an air bag according to the present invention corresponds to a gas generator, in which two combustion chambers are provided in a housing, and is characterized by a structure of arranging two combustion chambers. In particular, it is also possible to independently ignite and burn gas generating means accommodated in each combustion chamber by a different ignition means.
Namely, according to the present invention, there is provided a gas generator for an air bag, which includes, in the housing having a gas discharge port or gas discharge ports, ignition means activated upon an impact, and gas generating means ignited and burnt by the ignition means and generate a combustion gas for inflating an air bag, wherein, in the housing, two combustion chambers for storing the gas generating means are concentrically provided so as to be adjacent to each other in the radial direction of the housing, and a communicating hole to allow communication between the combustion chambers is provided.
Further, according to the present invention, there is provided a gas generator for an air bag, which includes ignition means activated upon an impact, and gas generating means ignited and burnt by the ignition means and generate a combustion gas for inflating an air bag in a housing formed in a cylindrical shape having an axial core length longer than an outermost diameter, having a plurality of gas discharge ports on a peripheral wall thereof, wherein, in the housing, two combustion chambers for storing the gas generating means are concentrically provided so as to be adjacent to each other in the axial direction and/or the radial direction of the housing, and a communicating hole to allow communication between the combustion chambers is provided.
It is possible to provide two combustion chambers concentrically to be adjacent to each other in the axial direction and/or the radial direction of the housing. The two combustion chambers are formed in a cylindrical shape and an annular shape.
As mentioned above, by forming two combustion chambers in the housing, it is possible to make an inner structure of the gas generator simple and independently burn the gas generating agents in the respective combustion chambers.
The gas generating means mentioned above is provided to inflate the air bag for restraining the occupant by the combustion gas generated by the combustion thereof. Accordingly, when the ignition means includes a transfer charge which is ignited and burnt by the igniter to burn the gas generating means, the combustion gas generated by the combustion of the transfer charge is used for burning the gas generating means and is not directly used for inflating the air bag. In this respect, both can be definitely distinguished from each other. Further, two combustion chambers provided in the housing is exclusively used for storing the gas generating means. In this respect, even when the ignition means is composed to include the transfer charge and the transfer charge is installed in a defined space (hereinafter, refer to as “an accommodating chamber”), this accommodating chamber of the transfer charge and the combustion chamber storing the gas generating means can be definitely distinguished from each other.
When the ignition means for igniting and burning the gas generating means includes two or more igniters to be actuated upon an impact, it is preferable that, in order to make the mounting thereof easy, the igniters are provided in a single initiator collar aligned to each other in the axial direction. Further, when the ignition means also includes the transfer charge which is ignited and burned in response to an activation of the igniters, it is preferable that the transfer charge is partitioned for each igniter, and independently ignited and burned by each igniter, and therefore is formed such that a flame of the transfer charge for one of the igniters does not directly ignite the transfer charge in any other igniters. As this type of structure, for example, it is possible to arrange the igniters in the respectively independent igniter accommodating chambers and then arrange the transfer charges in the igniter accommodating chambers, or to arrange the transfer charges in a place inside the independent combustion chambers where the transfer charges can be ignited and burnt in response to the activation of the igniter.
As mentioned above, in the case of dividing the transfer charge for
Iwai Yasunori
Katsuda Nobuyuki
Nakashima Yoshihiro
Ohji Nobuyuki
Daicel Chemical Industries Ltd.
Dickson Paul N.
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