Metal working – Method of mechanical manufacture – Assembling or joining
Reexamination Certificate
2001-05-15
2002-01-01
Cuda Rosenbaum, I (Department: 3726)
Metal working
Method of mechanical manufacture
Assembling or joining
C029S464000, C029S469000, C029S890124
Reexamination Certificate
active
06334245
ABSTRACT:
FIELD OF THE INVENTION
This invention is directed to an air bag gas generator for protecting a passenger from impacts, in particular to an air bag gas generator having a characteristic inner cylindrical member structure contained in a housing.
DESCRIPTION OF THE RELATED ART
A conventional air bag gas generator is constructed by forming a housing, having gas discharge ports, by casting, forging, or press work, etc., and providing, inside the housing, an igniting unit, gas generating agents, and a filter unit. Each of these is provided in the housing as is, or the inside of the housing is partitioned by an inner cylindrical member into two or more chambers. Each of the above-mentioned units, respectively, is provided in each of these partitioned chambers, as needed, according to their function.
When the inside of the housing is partitioned by the inner cylindrical member into two or more chambers, the cylindrical member is incorporated into the inner surface of the housing. Specifically, when the housing is formed by casting, the cylindrical member is incorporated into the housing in advance. When forming only the housing by press work, etc., a cylindrical-shaped inner cylindrical member, which is formed separately, is welded onto the inner surface of the ceiling of the housing.
However, when a separately formed inner cylindrical member is attached by welding, etc., to the ceiling portion of the inner surface of the housing, after the housing is formed, these two are welded from an outer surface of the housing. This makes determining the welding point difficult. Especially, when the inner cylindrical member is formed by pressing using a stainless steel sheet, etc., the circumferential wall of the cylindrical member is thin. This makes it more difficult to determine the welding point. If the point where the inner cylindrical member contacts the inner surface of the ceiling portion of the housing and the welding point from the outer surface of the housing are not accurately aligned, even slightly, the two members cannot be reliably attached. Furthermore, if holes are created in both members by welding, while the contact point and welding point are not accurately aligned, neither of these members can be used.
When the inner cylindrical member is joined to the inner surface of the ceiling portion of the housing afterwards, the inner surface of the ceiling portion of the housing ceiling is usually placed on the end surface of the inner cylindrical member and then fixed and secured to a jig. This led to the possibility of unstableness or misalignment (tilting) due to the small contact surface.
SUMMARY OF THE INVENTION
Therefore, the present invention resolves the above-mentioned problems by providing an air bag gas generator, in which an inner cylindrical member is welded to the ceiling portion of the inner surface of the housing after the housing is formed, where the inner cylindrical member can be reliably welded to the inner surface of the ceiling portion of the housing even if the welding point is slightly misaligned, and a gas generator having a cylindrical member, which can be welded to a ceiling portion of the inner surface of the housing without causing any instability (a more stable manner) in the area where the cylindrical member abuts the ceiling portion.
The air bag gas generator of the present invention is characterized, in particular, by the shape of the inner cylindrical member contained in the housing. It is further characterized that a broad width area is formed at an end portion of the inner cylindrical member for joining the ceiling of the inner surface.
In other words, the air bag gas generator of the present invention, which is constituted by partitioning the inside of the housing by the inner cylindrical member into two or more chambers, is characterized by the inner cylindrical member having the broad width area, extending inward or outward, at the end portion that joins the inner surface of the ceiling.
The inner cylindrical member can be formed by either casting, forging, or press or cutting work, etc., or a combination of these. When it is formed by press work, it can be formed, for example, by: the UO press method (the sheet is molded into a U shape, then molded into an O shape, and the seam is then welded); the electrical seam tube method (the sheet is molded into a disc shape, and the seam is welded with resistance heat by running a large electrical current while adding pressure to the seam.), etc. When it is formed by cutting work, a stainless steel rod can be cut into a desired size. The broad width portion formed at its end portion is extended to the degree needed to function as the welding area when the inner cylindrical member is welded onto the ceiling of the inner surface of the housing. As a result, the above-mentioned inner cylindrical member and the inner surface of the ceiling of the housing can be reliably joined via the broad width portion. This broad width portion can be, for instance, a flange formed by bending the end portion of the inner cylindrical member, which joins the inner surface of the ceiling of the housing to the outside or inside.
The above-mentioned housing can be formed by casting, forging, press work, etc., and it is preferably formed by welding a diffuser shell having gas discharge ports and a closure shell having an igniting unit storage opening. The two shells can be joined by various welding methods, such as electron-beam welding, laser welding, TIG welding, projection welding, etc. When the housing is formed by welding the diffuser shell and closure shell together, the cylindrical member is welded and incorporated into the inner surface of the circular area of the diffuser shell. The cylindrical member and the diffuser shell can be welded using various welding methods, as in the joining of the above-mentioned two shells. When the diffuser shell and closure shell are formed by press-molding a sheet steel, such as stainless steel sheets, etc., the manufacture of the two shells becomes easy and a reduction in manufacturing cost is achieved. Also, by forming the two shells into simple, cylindrical shapes, the press-molding becomes easy. As for the material for the diffuser shell and closure shell, stainless steel sheet is desirable, but nickel-plated sheet steel may be used.
In the gas generator of the present invention, the inner cylindrical member having the broad width portion is contained in the housing. Aside from this, it has structures and members required for its operation, and structures and members, which are effective for the operation of a gas generator, may also be used as needed. For the structures and members required for operating this gas generator, there are, for instance: an igniting unit, which is activated upon sensing an impact via a mechanical or electrical mechanism; gas generating agents, which are ignited by the activation of the igniting unit and burn and generate combustion gas; a filter unit, which purifies and cools the combustion gas generated; etc. On the other hand, for structures and members that are advantageous for the operation of the gas generator, there are, for instance: a filter support member, which is provided between an inner cylindrical member that partitions to form an igniting unit storage chamber on its inner side and the filter unit, and that which supports the filter unit; a short-pass preventing unit (plate member, etc.), which encloses the top end and/or bottom end of the inner circumference of the filter unit and which prevents the generated gas to pass through a gap between the filter unit and the inner surface of the housing; a cushion member, which is provided above and/or below the gas generating agents to prohibit the gas generating agents from moving; a perforated basket, which has multiple holes, is cylindrical in shape, and it prevents the gas generating agents installed inside of the filter means from directly contacting the filter unit. It also protects the filter unit from the flames from the combustion of the gas generating agents; a space, which is provided b
Katsuda Nobuyuki
Tomiyama Shogo
Cuda Rosenbaum I
Daicel Chemical Industries Ltd.
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