Land vehicles – Wheeled – Attachment
Reexamination Certificate
2000-11-16
2003-12-30
Dickson, Paul N. (Department: 3616)
Land vehicles
Wheeled
Attachment
C280S741000
Reexamination Certificate
active
06669230
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a multistage gas generator for an air bag and an air bag apparatus using the gas generator.
PRIOR ART
An air bag system which is mounted on various kinds of vehicles and the like including automobiles, aims to hold an occupant by means of an air bag (a bag body) rapidly inflated by a gas when the vehicle collides at a high speed so as to prevent the occupant from crashing into a hard portion inside the vehicle such as a steering wheel, a windscreen due to an inertia and being injured. This kind of air bag system generally comprises a gas generator to be actuated according to a collision of the vehicle and discharge a gas, and an air bag to introduce the gas to inflate.
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 is long or short, whether an adult or a child, and the like), a sitting attitude (for example, an attitude of holding on the steering wheel) and the like are different. Then, there has been conventionally suggested an air bag system which actuates, applying an impact to the occupant as small as possible 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 at two stages. U.S. Pat. Nos. 4,998,751 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 at two stages due to a expanded flame of the gas generating agent.
Further, in JP-A 9-183359, and DE-B 19620758, there is disclosed a gas generator in which two combustion chambers 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, these above conventional gas generators are not a multistage gas generator for an air bag with a simple structure which can be manufactured easily, suppressing the entire size of the container (housing).
DISCLOSURE OF THE INVENTION
The present invention provides a multistage gas generator for an air bag, wherein, at the initial stage of actuation, the gas generator is actuated to give a passenger as a small impact as possible, and according to variation of passengers' physiques (such that a sitting height is tall or low, adult or child) and sitting postures (such as clinging to a steering wheel), actuation output of the gas generator and timing of increase of output can be arbitrarily adjusted in order to restrain the passenger safely, and the gas generator can be manufactured easily with a simple structure, the entire size of the container (housing) can be suppressed, and finally the volume ratio of each combustion chamber can be arbitrarily be adjusted.
The present invention is characterized in an inner structure, specially a layout structure of the combustion chambers capable of suppressing the entire size of the gas generator and adjusting the volume ratio of each of the combustion chambers arbitrarily in a multistage gas generator for an air bag provided with a plural combustion chambers inside the housing thereof.
In other words, the multistage gas generator of the present invention having a cylindrical housing comprising a diffuser shell with a plurality of gas discharge ports formed in a cylindrical side wall and a closure shell forming a inner space with the diffuser shell, a plurality of combustion chambers for accommodating gas generating means provided in a cylindrical housing, and ignition means disposed in the respective combustion chambers to ignite and burn the gas generating means, wherein, in the housing, at least one of the combustion chambers is disposed in the inner side of an inner shell provided eccentrically with respect to a center axis of the housing, the ignition means provided for the respective combustion chambers are disposed eccentrically with respect to the center axis of the housing.
Further, in the gas generator of the present invention, a communication hole which allows mutual communication between the combustion chambers can be provided.
An automatic ignition material (AIM) which is to be ignited and burnt by transmitted heat may be disposed in either one of the combustion chambers.
The present invention further provides a multistage air bag apparatus which comprises the above-described gas generator, an ignition signal-outputting means provided with as many outputting portions, which outputs activation signals to the igniters on impact, as the igniters of the ignition means, and a plurality of lead wires having connectors, the igniters and the outputting portions are connected to each other through the lead wires having the connectors, and the connectors include defining means for deciding the unique connection between one of the connectors and one of the outputting portions.
The above gas generator may further comprise a cylindrical filter means for purifying and/or cooling an activation gas, one or both of axial end surfaces of the filter means may be formed as inclining end surfaces which get narrower in the axial extending direction and the interior angle with respect to the inner peripheral surface is an acute angle, and a supporting portion which is opposed to the inclining end surface of the filter may be provided in the housing (a self-contracting type filter).
In the present invention, most of an outer surface of the inner shell can be in direct contact with gas generating agent existing outside of the inner shell without interposing a heat insulator. The gas generating agent comes into contact with the outer surface of the inner shell where the communication hole is provided. A wall of the inner shell exists between a first gas generating agent which burns first and the other second gas generating agent. Even if the first gas generating burns, the second gas generating agent will never start burning before actuation of a second igniter, and the second gas generating agent is burnt by actuation of the second igniter before a temperature of the second gas generating agent reaches an ignition temperature by heat transfer.
After the first gas generating is ignited, if the gas generator is left standing without igniting the second gas generating agent, the second gas generating agent is ignited after about 10 seconds.
In the present invention, it is generally preferable that the inner shell is of cylindrical shape whose upper end is closed and its horizontal cross sectional shape is circular. The horizontal cross sectional shape of the inner shell may be formed into various shapes such as rectangular shape and elliptic shape. However, it is desirable to form the horizontal cross sectional shape of the inner shell into circular in view of easiness of connection. The inner shell is disposed in the housing eccentrically with respect to the center axis of the housing. That is, the inner shell is disposed in the housing such that a center of the inner shell does not coincide with a center of the housing, and the inner shell is disposed in the housing eccentrically with respect to the cylindrical housing. Therefore, even if the plane shape of the housing is substantially elliptic, in case that the center of the plane shape and the center of the inner shell are deviated from each other, the inner shell and the housing are deviated from each other. Besides, the center axis of the housing is specified exclusively based on the plane shape of the cylindrical body, and even if the housing has a flange for mounting the housing to the module, the flange is not taken into consideration when the center axis of the housing is specified.
The ignition means disposed in the respective combustion chambers include an igniter which is actuated by electric signal. The igniters can be provided aligne
Katsuda Nobuyuki
Nakashima Yoshihiro
Ohji Nobuyuki
Birch & Stewart Kolasch & Birch, LLP
Daicel Chemical Industries Ltd.
Dickson Paul N.
Sliteris Joselynn Y
LandOfFree
Multistage gas generator for air bag and air bag apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Multistage gas generator for air bag and air bag apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Multistage gas generator for air bag and air bag apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3160922