JPH0516762A - Inflator vessel for air bag - Google Patents

Abstract

PURPOSE:To realize light weight trend while keeping sufficient proof pressure in a cylindrical inflator vessel for an air bag by forming at least one part of a center fixed part having a space to receive an ignition means into a thick wall, and joining a cover part and a vessel main body part together by friction welding. CONSTITUTION:An inflator to receive gas generating agent 4 for an air bag is constituted of a vessel main body part 1 and a cover part 2, and on the center of this interior, a center fixed part 3 having a space to receive an ignition means 5 is provided. The center fixed part 3 is formed thick at least on a part of the outer circumferential face. It is divided into two parts and respective pats are respectively joined to the vessel main body 1 or the cover part 2 by friction welding, and they are formed into one body by threaded fastening, otherwise, it is not divided, joined to the vessel main body 1 by friction welding, hereafter, joined to the cover part 2 having an opening part. Hereby, pressure at combustion of the gas generating agent 4 is borne with both end plate parts and the center fixed part 3 of the cylindrical vessel, and another part can be made thin to realize light weight trend.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an airbag inflator container.

[0002]

2. Description of the Related Art When a vehicle encounters an accident such as a collision,
A so-called airbag is known as a safety device for protecting passengers. When the vehicle suddenly stops or decelerates at the time of an accident, this airbag is used as an air cushion by inflating the bag incorporated in the steering wheel, instrument panel, etc. with the gas generated by the combustion of the gas generating agent. It is provided between the occupant and the vehicle structure to prevent a secondary collision between them and to protect the occupant.

An air bag is usually composed of a bag, a cover for housing the bag, and an inflator filled with a gas generating agent. Since the inflator has a pressure resistant structure so as to withstand the pressure of the combustion gas when the air bag is activated, the inflator has a large weight and accounts for 40 to 70% of the total weight of the air bag.

[0004]

In order to reduce the weight of the vehicle,
Naturally, it is also desired that the airbag mounted on this be lightweight. However, the airbag is an emergency safety device, and it must be able to sufficiently withstand the combustion pressure of the gas generant in order to ensure that it performs its intended function. And increasing the pressure resistance leads to an increase in weight. The weight reduction of the airbag has to be realized under these constraints, which is quite difficult. This weight reduction is particularly important for the inflator of the driver's airbag that is placed inside the steering wheel of the automobile. It is made of lightweight aluminum, the outer periphery of which is welded, and the central portion is made of steel. How to maintain strength at the support (usp4530516)
However, in this method, the airtightness of the central fixing portion made of steel is uncertain, and the curing step is complicated and the step becomes complicated when sealing is performed by adhesion, sealant or the like. Therefore, it is difficult to say that the inflator has a reliable environmental seal for protecting the operating characteristics of the inflator, and is lightweight and highly reliable with a simple process.

The present invention has an object to provide an inflator container having a lightweight structure under such circumstances.

[0006]

As a result of earnest studies on a pressure resistant structure that is easy to manufacture an inflator container, the present inventor has conventionally made the entire container a thick structure to withstand the pressure at the time of combustion of the gas generating agent. The present invention has been made based on the finding that it is possible to reduce the thickness of other members only by increasing the thickness of only the specific member of the container as the strength member.

That is, according to the present invention, the container body and the lid are
In a cylindrical airbag inflator container, which is integrally arranged at the center of the inside thereof and has a space portion for accommodating the ignition means, the center fixing portion has at least an outer peripheral surface thereof. An inflator container for an air bag, characterized in that a part thereof is formed thick.

In the inflator container of the present invention, the pressure at the time of combustion of the gas generating agent can be held by both end plate portions of the cylindrical container and the central fixing portion integrated in the inner end of the container. It is a thing. That is, by forming at least a portion of the wall thickness of 3.5 to 4 mm, which is the same as in the conventional inflator container, at the central fixed portion of the end plate,
Others can be thinned to about 2 mm. This greatly reduces the weight of the entire inflator container (40 to 60
%) Can be realized.

[0009]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a sectional explanatory view of an airbag inflator container of the present invention, FIG. 2 is a sectional explanatory view of a container main body portion, and FIG. 3 is a sectional explanatory view of a container lid portion.

Although the inflator container of the present invention has a cylindrical shape, its cross section does not have to be a perfect circle, and may be an elliptic shape.

As is apparent from the figure, the central fixing portion has a thick structure and has a space portion for accommodating the ignition means therein. In addition, the fixed portion is provided with an appropriate number of holes for communicating the combustion chamber defined by the inner cylinder with the ignition means housing space. An inner filter and a gas generating agent are incorporated inside the combustion chamber inside the container, and an outer filter is incorporated outside the combustion chamber.

The gas generating agent generates a gas necessary for expanding the airbag, and is, for example, sodium azide,
A molded body (pellet, disc with a central hole, etc.) of an autonomously combustible composition comprising an oxidant, an additive, etc., which is ignited by an ignition device to generate gas. At this time, unnecessary residues are generated in addition to the necessary gas. The inner filter collects a part of the unnecessary residue and cools the gas. The inner cylinder partitions the combustion chamber, holds the inner filter, and has a communication hole through which the combustion gas generated from the gas generating agent can flow to the outside. Since this communication hole facilitates ignition and combustion of the gas generating agent and shuts off from the outside air, it is usual to install a seal having a structure capable of easily breaking at a predetermined internal pressure and withstanding a relatively small external pressure. . Aluminum foil or the like, for example, is arranged in this seal so as to close the communication hole inside the inner cylinder. The outer filter is not particularly limited as long as it collects the residue coming out of the combustion chamber and cools the gas. For example, it is preferable that the outer filter is divided into upper and lower layers, and the two layers are arranged so that the first layer is placed on the outer peripheral portion of the communication hole provided in the inner cylinder, and the second layer is further provided inside the gas outlet of the container.

The inflator made according to the present invention is a pressure-resistant container having a cylindrical shape and having end plates at both ends, and the outer surface thereof is made. The plate thickness of this mirror plate can be reduced as it approaches the spherical mirror plate. However, since the airbag for the driver's seat needs to be made compact, the height cannot be increased, and a substantially flat end plate is used. In order to prevent the deformation of the plane mirror plate, the plate thickness must be significantly increased.
Since the inflator of the present invention can allow the flat mirror plate to be deformed by the pressure during operation (there is no effect on other characteristics due to the deformation), the thin-walled part of the mirror plate is deformed into a curved surface shape, and the pressure resistance is increased. There is a big feature that you can do it.

When the thin portion of the end plate is deformed into a curved surface in the axial direction, the strength member that withstands the axial pressure of the end plate includes a central fixing member welded to the lid portion, and the welded lid and container body edge portion. Are both. Since the central fixing member has a small diameter, the area capable of bearing the axial force tends to be small, and in order to compensate for this, a part of the outer circumference needs to be thickened. The thickness can be reduced except for the necessary thick portion.

In the present invention, the central fixing portion may be divided as shown in the figure and joined to the container main body portion and the lid portion by friction welding, and then integrated by screwing. Alternatively, the central fixing portion may be divided. Instead of forming the body, the container body may be integrally friction-welded and subsequently joined to the lid having the opening.

In the present invention, the formation of the central fixing portion in the inflator container can be easily realized by integrating a tubular body serving as the central fixing portion with the container main body and / or the lid by friction welding.

In the present invention, it is important that at least a part of the central fixing portion has a thick structure similar to the conventional one.
Other technical matters such as other structure and material of the inflator container are not particularly limited.

[0019]

As described above, in the inflator container of the present invention, the thick portion can be limited only to the central fixing portion, and the other portions can be made thin, so that a great weight reduction can be realized. You can

[Brief description of drawings]

FIG. 1 is a sectional explanatory view of an airbag inflator container of the present invention,

FIG. 2 is an explanatory cross-sectional view of the container body,

FIG. 3 is an explanatory cross-sectional view of the container lid portion.

Claims (2)

[Claims] 1. A cylindrical airbag inflator container comprising a container body, a lid, and a central fixing portion integrally provided in the center of the interior of the container and having a space for accommodating the ignition means. An airbag inflator container, wherein at least a part of an outer peripheral surface of the central fixing portion is formed thick. 2. The airbag inflator container according to claim 1, wherein the press-molded container body and / or the lid and the central fixing portion are friction-welded.