MXPA97003452A - Liquid gas generator - Google Patents

Abstract

A liquid gas generator for inflatable air bags that protect passengers from vehicles in the event of a collision has a housing, a closed liquid gas reaction vessel (7) arranged in the housing, a cavity (9) arranged in the housing close to the reaction vessel (7), a trigger element (4) and a penetrating element (16) movable in the cavity penetrating a wall of the reaction vessel (7) when the trigger element (4) is actuated, allowing the combustion gases of the liquid gas to escape from the reaction vessel (7) into the cavity (9) and out of the housing into the air bag. In order to make it easier to open and penetrate the reaction vessel (7) and generate gas in a controlled and reproducible manner throughout the service life of the liquid gas generator, the penetrating element (16) penetrates the entire length of the wall of the reaction vessel (7) and fully penetrates the reaction vessel (

Description

Liquid gas generator The invention relates to a liquid gas generator according to the preamble of claim 1. With passive safety devices for motor vehicles, in which the impact protection pads protect the drivers or passengers in the vehicle. front seat of injuries caused by impact against the steering wheel or dashboard (also called Air Bag), liquid gas generators that have a solid propellant charge, or gas generators that have condensed gas which is under pressure (hybrid generator, compressed air generator), or even generators that have liquid gas mixtures which participate in a partially active combustion, are used for gas generation. The advantages of gas mixtures compared to solid propellant charges when used in a generator are well known. A problem in the case of gas generators, or even liquid gas generators, is that the gases that are under pressure must be enclosed in a container which in the case of use, that is, operational activation of the generator, must be open in a definite way. From DE 42 41 221 Al a liquid gas generator for an inflatable impact protection pad is known to protect a motor vehicle passenger from injury. The liquid gas generator has a housing in which a reaction vessel is accommodated with liquid gas. In order to activate the combustion of the liquid gas, a penetrating element having a transfer duct is driven towards the reaction vessel. The kinetic energy for the penetrating element is pyrotechnically produced by initiating a lighter element. The igniting vapors of the lighter element reach the interior of the reaction vessel through the transfer duct and there start the combustion of the liquid gas. The combustion gases which are produced in this connection leave the reaction vessel via the transfer duct and reach a chamber in which the penetrating element is placed. The chamber is closed from a discharge space (direct path) by a rupture membrane. This rupture membrane breaks when a minimum pressure of the combustion gases is reached and consequently frees the way for the elimination of the combustion gases from the whole by means of the discharge space (direct path). A disadvantage of this is that the penetrating element, or the firing piece, has to be directly supported against the reaction vessel, because otherwise pressure may accumulate behind the firing part which prevents the reaction vessel from being penetrated . Apart from this there is a danger that the firing piece will be loaded asymmetrically, which in turn can lead to uncertainties with penetration. A substantial disadvantage is, in addition, the rupture membrane which is required and by means of which the chamber is constructed as a pressure space. First of all, these rupture membranes are extremely expensive and secondly when a rupture membrane is used, a reaction occurs by the outgoing gas, which reaction transmits an unwanted moment of rotation to the gas generator. The fundamental objective of the invention is to improve a liquid gas generator according to the preamble of claim 1 in such a way that the opening or penetration of the reaction vessel is simplified and in such a way that during the entire operation, the generation of gas is done in a controlled and reproducible manner. In order to achieve this objective, according to the invention, a liquid gas generator is proposed, whose housing contains a closed reaction vessel for containing the liquid gas. In the housing a chamber is formed, which abuts the reaction vessel when the latter is inserted. Placed in a displaceable way in the camera there is a penetrating element, whose total length is driven through the wall of the reaction vessel when a lighter element is ignited and completely immersed in the reaction vessel. As a result of the penetration or perforation of the wall of the reaction vessel by the penetrating element and the additional penetration of the penetrating element into the reaction vessel, which was previously closed, there is consequently a connection with the diameter of the penetrating element. A substantial advantage lies in the fact that there is no separate pressure space having a rupture disc. As a result of this, a decisive price advantage is given. Because there is no rupture disc, a symmetric discharge must be achieved simply by a comparatively large number of discharge paths over the diameter. As a result of this, an unwanted reaction or rotation moment is avoided. An additional advantage consists of the simple structure of the gas generator, which must be produced almost solely from rotationally symmetrical components. The penetrating element is advantageously a solid body. In a preferred embodiment according to the invention, for better penetration / perforation of the wall of the reaction vessel, the penetrating element has the shape of a projectile, that is, a cylinder with a cone, sphere, cylinder, etc., installed in the same.

In an advantageous embodiment, the lighter element contains a fulminating capsule. In order to activate the liquid gas generator, the igniter element or the capsule is ignited. The combustion gases which are produced when the igniter element is ignited drive the penetrating element through the wall of the reaction vessel. In this case, the lighter element and the penetrating element are connected to each other in such a way that in each case a clean perforation of the separating wall is guaranteed. Because the resulting hot gases enter the reaction vessel and the liquid gas mixture flows into the chamber, ignition and reaction of the liquid gas mixture occur. The combustion gases that are produced begin in the transfer ducts which leave the chamber. As a result of the shape, position and diameter of the transfer ducts, the gas generation can be controlled and performed in a reproducible manner. As a result of this, the use of expensive rupture discs in this region can be eliminated. The combustion gages entering the transfer ducts exit the gas generator through the discharge paths in the housing and then inflate the bent impact protection pad. As already mentioned, the penetrating element advantageously has the shape of a projectile in order to guarantee a certain and defined penetration of the separating wall. The penetrating element is advantageously connected to the lighter element or a sleeve by means of a ripping edge, so that only after a defined pressure has been produced, caused by the combustion gases of the lighter element, the penetrating element can begin to move. with high energy. Alternatively, a radial extension in the penetrating element can be arranged and / or a radial narrowing in the guide sleeve can be arranged. In order to achieve the energy which is required to penetrate the wall, between the penetrating element and the lighter element there is a conveniently arranged chamber (use of the combustion gases). The camera is filled in a profitable way with a load. The filler is conveniently a pyrotechnic propellant charge powder or ignition composition such as nitrocellulose, a mixture of potassium boron nitrate or a mixture of black powder. According to the invention, the lighter element is advantageously provided with a cylindrical guide sleeve for guiding the penetrating element.

The penetrating element conveniently consists of a molded part of thermal stable fuel, which, after penetrating the reaction vessel, is burned by the high temperature that occurs during the gas reaction. A further advantage is the fact that, in the event that the penetrating element flows back through the opening, the penetrating element can no longer block a transfer duct during combustion. The penetrating element, the ripping edge and the sleeve are preferably a molded part. The wall of the reaction vessel that will be derailed by the penetrating element is conveniently a rupture disk, which is preferably integrated into the lid of a sealing plug of the reaction vessel. Additional features arise from the figures, which are described below. Figure 1 shows in section a liquid gas generator according to the invention, Figure 2 shows in partial section a first embodiment of a lighter element and Figure 3 shows in section a second embodiment of a lighter element. Figure 1 shows a liquid gas generator 1 according to the invention, which substantially comprises a head portion 2, a base portion or adapter 9 and a cylindrical discharge tube 10. Discharge paths 10 are found in the discharge tube 10. of discharge 11 arranged. Apart from this, it is arranged in the discharge pipe 10, or in the liquid gas generator 1, a reaction vessel 7 as a resistant bottle of its own pressure. The liquid gas, or a mixture of liquid gas, is in this reaction vessel 7. The reaction vessel 7 is used as a storage vessel, as well as a combustion chamber for the liquid gas mixture. The element face of the reaction vessel 7 is closed by means of a rupture disk 5. The rupture disk 5 is in this case integrated in the lid of a sealing plug 18. This sealing plug 18 is screwed to the portion of head 2 by means of a thread 20, in such a way that a chamber 19 abuts the rupture disc 5. From chamber 19, transfer ducts 6 are directed to the space between reaction vessel 7 and the discharge tube 10. Arranged in the head portion 2 there is also a support 3 of the lighter element having a lighter element 4. The front point of the lighter 4 has a penetrating element 16 which has the shape of a projectile and projects with the penetrating element a the chamber 19. The lighter element 4 is located on the longitudinal axis 21 of the reaction vessel 7. The reaction vessel 7 is conveniently made of hardened steel. The housing is made in the same way as steel or aluminum. Figure 3 shows a variant of the lighter element 4. The lighter element 4 is inserted into the support 3 of the lighter element. The igniter element 4 comprises a capsule 12 and a chamber between the penetrating element 16 and the capsule 12, the chamber being filled with a charge 13. The penetrating element 16 is firmly connected to the igniter element 4 by being molded on a sleeve 14 having a tearing edge 15. In the case of a lighting, the igniter element 4 is ignited, the gases and heated particles that are produced ignite the load 13. Because the penetrating element 16, which is firmly connected to the support 3 of the element lighter by means of the sleeve 14 and the tear edge 15, can not begin to move, a pressure build-up determined by the strength of the tear edge 15 occurs. After a certain defined pressure has been reached, then a tear between the penetrating element 16 and the sleeve 14 is made very quickly at the tear edge 15. As a result of the guide sleeve 17 of the support 3 of the lighter element, a directed acceleration of the penetrating element 16 occurs. The penetrating element is accelerated in a defined manner in the guide sleeve 17 by the pressure of the combustion gas (beginning of a bullet in a small barrel). After the penetrating element 16 has been separated from the support 3 of the lighter element or the lighter 4, the penetrating element 16 passes through the chamber 19 of the portion head 2 and penetrates the rupture disc 5, which separates the mixture from liquid gas in the combustion chamber 8 of the head portion 2 or the chamber 19 (see Figure 1). The liquid gas mixture is ignited in the combustion chamber 8 by the hot gases and hot particles of the igniter element 4 resulting from the penetrating element 16. A volume expansion is effected in the chamber 19 of the head portion 2 through the opening in the rupture disc 5 and consequently begins the inflation of the gas sac through the transfer ducts 6 and the discharge paths 11. The gas development and the increase of the pressure in the chamber 19 of the portion head 2 can be controlled in a manner defined by the position, diameter and number of discharge ducts 6. The penetrating element 16 can consist of a molded part of thermally stable fuel (plastic or metal material), which has the shape of a projectile. As a result of the high temperature that results during the reaction of the liquid gas mixture, the penetrating element 16 burns after the combustion chamber has penetrated 8. Figure 2 shows a mode of the penetrating element 16 and the load 13 which is a little different from Figure 3. The penetrating element 16 is not connected here. to the sleeve 14 or the lighter 4 by means of a tear edge 15. Instead, a radial extension 31 is arranged in the penetrating element. Alternatively, a radial constriction 30 can also be provided in the guide sleeve. Both measurements effect, like the tear edge 15 in Figure 3, a directed acceleration of the penetrating element 16 only after a certain pressure has been reached.

Claims (12)

1. Claims 1. Liquid gas generator for an inflatable impact protection pad to protect a motor vehicle passenger from injury, having - a housing, a closed reaction vessel, which is arranged in the housing, to contain the liquid gas , a chamber in the housing, which abuts the reaction vessel, a lighter element, and a penetrating element, which can be moved in the chamber, to penetrate a wall of the reaction vessel when the lighter element is started, the in which case the flue gases of the liquid gas leave the reaction vessel to the chamber and from there outside the housing to the impact protection pad, characterized in that the entire length of the penetrating element penetrates the single wall of the reaction vessel and completely submerges the reaction vessel.
2. 2. Liquid gas generator according to claim 1, characterized in that the penetrating element is a solid body.
3. 3. Liquid gas generator according to claim 1 or 2, characterized in that the penetrating element has the shape of a projectile.
4. Liquid gas generator according to one of the claims 1 to 3, characterized in that the penetrating element is connected to the igniter element or to a sleeve by means of a ripping edge.
5. Liquid gas generator according to one of the claims 1 to 4, characterized in that the penetrating element consists of a molded portion of thermal stable fuel.
6. 6. Liquid gas generator according to claim 4 or 5, characterized in that the penetrating element, the rip edge and the sleeve are a molded part.
7. Liquid gas generator according to one of the claims 1 to 6, characterized in that the lighter element is provided with a cylindrical guide sleeve for guiding the penetrating element.
8. Liquid gas generator according to one of the claims 1 to 7, characterized in that a radial extension is arranged in the penetrating element and / or a radial narrowing is arranged in the guide sleeve.
9. 9. Liquid gas generator according to one of claims 1 to 8, characterized in that the lighter element contains a capsule fulminant.
10. Liquid gas generator according to one of claims 1 to 9, characterized in that a chamber, which is preferably filled with a load, is arranged between the lighter element and the penetrating element.
11. 11. Liquid gas generator according to one of claims 1 to 10, characterized in that the single wall of the reaction vessel is a rupture disk.
12. 12. Liquid gas generator according to claim 11, characterized in that the rupture disk is integrated in the lid of a sealing cap of the reaction vessel.