MXPA97006281A

MXPA97006281A - Generator of gas of type of construction of metal sheet, for a device of protection of passengers of a vehicle of mo

Info

Publication number: MXPA97006281A
Application number: MXPA/A/1997/006281A
Authority: MX
Inventors: Bayer Karl; Brede Uwe
Original assignee: Dynamit Nobel Ag 53840 Troisdorf De
Priority date: 1995-02-18
Filing date: 1997-08-18
Publication date: 1998-02-01

Abstract

The present invention relates to a gas generator of the sheet metal construction type for a protective device, of concentric construction, for the occupants of a motor vehicle, having fitted around an ignition chamber that has a lighter and a load of ignition, a combustion chamber that has a gas generating charge, the combustion chamber is surrounded by an expansion chamber, the metallic sheet parts that form the combustion chamber and the expansion chamber are connected to each other only by work metallic, and the gas generating charge is adapted to the combustion chamber in a hermetically sealed cargo container.

Description

GENERATOR OF GAS TYPE OF CONSTRUCTION OF METAL SHEET. FOR A PASSENGER PROTECTION DEVICE FOR AN ENGINE VEHICLE The invention relates to a gas generator of the sheet metal construction type, for a passenger protection device of a motor vehicle, according to the preamble of claim 1. The gas generator, of the type described, It is known from DE-A1 41 21 039. This gas generator is a combustion chamber, built concentrically, and a gas generating charge is arranged around an ignition chamber with a lighter and ignition charge and the The combustion chamber is surrounded by an expansion chamber. The expansion chamber contains a space that collects dust and a cooling / expansion space. The gas, which escapes through the discharge openings from the combustion chamber, is divided into a primary flow and a secondary flow. The primary flow is forced into the space that collects the dust, while the purified gas is transported through the cooling / filter space within the gas pocket of the air bag. By increasing the speed of the escaping gas, a high separation efficiency can be obtained. This is achieved by the intrinsic energy of the gas discharge.

The fundamental object of the invention is to improve a gas generator, according to the preamble of claim 1, in such a way that lower manufacturing costs, low weight and good recycling properties are combined with a small overall size. This object is achieved, according to the invention, by having the metal sheet parts, which form the combustion chamber and the expansion chamber, connected to each other exclusively by metal forming techniques. Metal forming techniques are understood as beading, edge rolling, riveting, oscillating riveting, upsetting, pressing and milling. By connecting the individual pieces of sheet metal exclusively by means of metal forming techniques, it is possible to achieve low manufacturing costs simultaneously with a smaller overall size and a lower weight. Also, by virtue of the good recycling properties, waste disposal is guaranteed. In a preferred embodiment, the combustion chamber is formed by two pieces of metal sheet, of which the internal part comprises a cylindrical internal wall with a bottom piece bent at right angles to one end and the outer part comprising an outer wall cylindrical with a top piece bent at right angles at one end.

According to the invention, the ignition chamber is a prefabricated ignition element, which is arranged in the internal cylindrical wall of the internal part of the combustion chamber. In this way, an extremely compact structural configuration with few parts is achieved. According to the invention, the pieces of metal sheet are steel plates, for example special steel 1.4301 or 1.4303, which has a wall thickness preferably of 1.0 to 1.5 mm. The charge that generates gas in the combustion chamber is advantageously arranged in a hermetically sealed storage container. The latter is preferably made of aluminum and is manufactured by extrusion or deep drawing and is absolutely impermeable to external moisture. The wall thickness of the storage container preferably has about 0.2 to 0.5 mm. The exit openings, which generate rotation, are arranged between the combustion chamber and the expansion chamber. In a preferred embodiment, these outlet openings take the form of hood-shaped protuberances of the cylindrical outer wall of the external part of the combustion chamber. These protuberances are formed by cutting in and pressing out the wall of the combustion chamber. In comparison with the prior art, therefore, it is possible to dispense with an additional structural part. The expansion chamber advantageously comprises a separation chamber which is connected to the outlet openings and a filter chamber which is arranged, in the direction of flow, downstream thereof, the escaping gas is re-directed through about 180 ° when passing from the separation chamber to the filter chamber. As a result of such abrupt change in direction and in cooperation with the high centrifugal force caused by the rotation of the exhaust gas, a large proportion of the liquid and solid particles, which do not follow the change in direction, are separated from the gas flow. The filter chamber is preferably occupied by a filter structure. As a result, further filtration and cooling of the gas is performed. In a preferred embodiment, a longitudinal wall of the filter chamber is positioned opposite the outlet openings and this first longitudinal wall is inclined with respect to the wall of the combustion chamber (outer cylindrical wall of the outside of the chamber combustion), thus producing a reduction in diameter in the direction of the flow of escaping gas. The required increase in the speed of escaping gas is achieved in this way.

For subsequent filtration, a wall of the separation chamber is covered by a filter. This filter preferably comprises a mesh or woven wire fabric. The gas generator, according to the invention, is very suitable as a gas generator for the driver, ie the driver's side of a motor vehicle. Additional features of the invention are apparent from the drawings and the detailed description that follows. The drawings show: Figure 1 a gas generator according to the invention, in section; Figure 2 a section along line A-A of Figure 1; Figure 3 a detail with the ignition element of an alternative form of security and Figure 4 a section through the expansion chamber of an alternative embodiment. Figures 1 and 2 show a gas generator constructed concentrically, according to the invention, of the sheet metal construction type, which is for a passenger protection device of a motor vehicle. A combustion chamber 2 and an expansion chamber 4 are arranged around an ignition element 9. These chambers 2, 4 are made of special steel, exclusively by the techniques of metal forming.

The combustion chamber 2 is assembled from two pieces of metal sheet, ie an internal part 5 and an external part 6. The internal part 5 comprises a cylindrical internal wall with a bottom part 7 bent at right angles at one end. The external part 6 is a cylindrical outer wall, with an upper part 8 bent at an angle at one end. The two parts 5, 6 are connected together by the edge formation. An ignition element 9 is arranged inside the combustion chamber 2. To achieve this, a retaining plate 17, against which the ignition element 9 is applied, is incorporated in the wall of the combustion chamber 2. The element Ignition 9 is held by a sleeve 30, which is pressed by means of flanges on the ignition element 9. The inner part 5 and the sleeve 30 are preferably connected together by welding. Figure 3 shows the inner part 5 of the combustion chamber 2 at an enlarged scale, compared to Figure 1, and with the ignition element 9 inserted. The fastening is performed by riveting, that is to say by the wall 18 of the internal part 5 which is pressed radially in the form of points into a cavity in the ignition element 9. The ignition element 9 is of the prior art and comprises a socket 19 for connection to a socket and connection to an electronic control device.

Arranged within the ignition element 9 is an ignition bridge (not shown) which, when a voltage is applied, ignites a detonating agent, which in turn causes an ignition charge 1 to ignite. Arranged in the combustion chamber 2 is a storage container 10, which comprises an annular pot with a lid 20. The pot and lid 20 are locked by sewing together. For sealing purposes, the sealing region is provided with a coating, such as, for example, an acrylate adhesive coating. The charge generating gas 3 in the form of pellets of the impeller is housed inside the storage container 10. A volume compensator 21 and a woven wire fabric 22 are further provided, which prevents blocking of the outlet openings 11. The woven wire cloth 22 is arranged for such purpose at a specified distance from the wall of the storage container 10 and extends over the entire length of the storage container 10. Arranged in the internal part 5 of the combustion chamber 2, there are the holes 23, which allow the ignition flash of the ignition element 9 to enter the combustion chamber 2. After the ignition of the element 9 has been started, the ignition flash from the ignition element, of course, penetrates the storage container 10 and ignites the charge 3 which generates gas. After a specific pressure of rupture has been reached, the storage container 10 is opened in the outlet openings 11 of the combustion chamber 2. These outlet openings 11, in the form of hood-shaped protuberances or segment openings preferably in the configuration of a rectangle or segment of a circle, they are pressed outwards, thus achieving a tangential discharge of the gas from the combustion chamber 2. Preferably, twelve outlet openings 11 are uniformly disposed at the periphery. Arranged adjacent to the combustion chamber 2 is an expansion chamber 4 comprising a separation chamber 12 and a filter chamber 13. The escaping gas passes out of the outlet openings 11 within the separation chamber 12, where it is It spirals to the base plate. In the region of the base plate, the gas flow is abruptly redirected through about 180 ° and passes through the openings 26 within the filter chamber 13, which is filled with the mass 14 of the filter. The openings 26 are arranged immediately after the transition from vertical to horizontal. Working together with this action is the high centrifugal force caused by the rotation and, as a result, a large proportion of liquid and solid particles, which did not follow the change of direction, are separated from the gas flow. The liquid and solid particles separated from the gas in this way are retained in a mesh or woven wire cloth, joined as the filter 16 to the outer wall of the separation chamber 12. For the subsequent filtration and cooling, the gases flow through the filter 14 in the filter chamber 13 and also flow through the outlet openings 24 in the air bag. The filter 14 is preferably composed of a thick woven fabric for cooling and a braid texture for fine filtration. Figure 4 shows a special construction of the expansion chamber 4. Here, the longitudinal wall 15 of the filter chamber 13 which is placed opposite the outlet openings 11 of the combustion chamber 2 is inclined with respect to the wall of the combustion chamber (outer cylindrical wall of the external part 6 of the combustion chamber 2), thus producing a reduction in diameter in the direction of the flow of the escaping gas, the longitudinal wall 15 rests on a spacing rim 25, in which the openings 23 are also arranged. The spacing flange 25 and the longitudinal wall 15 are simply inserted into the expansion chamber 4.

As already revealed in Figure 1, the expansion chamber 4, in the embodiment according to Figure 4, similarly comprises only two sheets of metal, ie a bottom sheet 27 and a peripheral part 28, with an upper part 29 curved. The gas generator described is remarkable for the following advantages: »connection of the individual parts of sheet metal by means of metal forming techniques, such as beading and edge lamination, make it possible to obtain low manufacturing costs; »The use of steel plates allows for a compact and lightweight construction style; 4 the tangential flow outside the segment openings, which establishes the rotation of the gas flow, combined with the abrupt change in the direction of the gas fumes, performs a high degree of separation and allows the use of construction filter units simple; * good recycling properties through the use of only one material for housing and filtration, for example special steel 1.4301.

Claims

CLAIMS 1. A gas generator of metal sheet construction type, for a device protecting the passengers of a motor vehicle, this gas generator has a concentric style of construction, with a combustion chamber that has a load which generates gas arranged around an ignition chamber, which has a lighter and an ignition charge, and the combustion chamber is surrounded by an expansion chamber, characterized in that the parts of metal sheets, which form the combustion chamber and the expansion chamber are connected to each other exclusively by metal forming techniques. The gas generator, according to claim 1, characterized in that the combustion chamber is formed of two parts, of which the internal part comprises a cylindrical internal wall with a bottom part curved at right angles to one end and the outer part comprises a cylindrical outer wall, with an upper part curved at right angles at one end. 3. The gas generator, according to claim 1 or 2, characterized in that the parts of metal sheets are made of steel plates. The gas generator according to one of claims 1 or 3, characterized in that the ignition chamber is a prefabricated ignition element, which is arranged in the internal cylindrical wall of the internal part of the combustion chamber. The gas generator according to one of claims 1 to 4, characterized in that the gas generating charge, inside the combustion chamber, is arranged inside a hermetically sealed storage container. 6. A gas generator, having outlet openings that generate rotation, between the combustion chamber and the expansion chamber, according to one of claims 1 to 5, characterized in that the outlet openings take the form of protrusions in Hood shape of the outer cylindrical wall of the external part of the combustion chamber. The gas generator according to one of claims 1 or 6, characterized in that the expansion chamber comprises a separation chamber attached to the outlet openings and a filter chamber that is positioned in the direction of the direction of flow, downstream thereof, the exhaust gas, when passing from the separation chamber to the filter chamber is redirected through an angle of approximately 180 °. 8. The gas generator, according to claim 7, characterized in that the filter chamber is occupied by a filter structure. The gas generator, according to claims 7 or 8, characterized in that the first longitudinal wall of the filter chamber is positioned opposite the outlet openings. The gas generator, according to claim 9, characterized in that the first longitudinal wall is inclined with respect to the wall of the combustion chamber (cylindrical external wall of the external part of the combustion chamber), thus producing a reduction in diameter in the direction of the flow of escaping gas. The gas generator according to one of claims 7 to 10, characterized in that the first wall of the separation chamber is covered by a filter.