DE102007010066A1 - Inflation device for airbag, has compressed gas storage and ventilation opening, which are closed with diaphragm, on whose outer side actuator is arranged - Google Patents

Abstract

The inflation device has a compressed gas storage and a ventilation opening, which are closed with a diaphragm (17), on whose outer side an actuator is arranged. The diaphragm covers a slit shaped exhaust port (21) and a feed channel (15) of the actuator, arranged adjacent to the exhaust port and overlie on a bar between the feed channel and the exhaust port.

Description

The The invention relates to an inflator for an airbag with a compressed gas storage with a ventilation opening, which is closed with a membrane and associated with an actuator is that destroys the membrane in the presence of appropriate sensor data.

The EP 0 790 157 B1 describes a hybrid inflator having a pressurized gas container and a combustible material that provides heat and supplemental inflation gas, thereby increasing the volume and pressure of the stored pressurized gas. In a reaction housing for inflating an airbag, a pressure bottle is arranged, which contains compressed gas. The pressure inside the pressure bottle depends on the ambient temperature. The stored gas is held by a shutter disc in the pressure bottle. Furthermore, the hybrid inflator comprises a gas generator with a propellant contained therein. The gas generator is disposed within the pressure bottle and includes an igniter assembly for the propellant. If an igniter is activated, a projectile is driven through the shutter disc, whereby a stream of compressed gas can enter the airbag. Subsequently, the projectile strikes an activation plate, whereby an ignition charge is activated to ignite the propellant. On the inflator, a vent assembly is arranged on the pressure bottle, which comprises a tubular sleeve. A flange extends outwardly from one end of the sleeve. Attached to the flange is a burstable membrane which extends across the sleeve to seal the pressure bottle. Attached to an end wall of the sleeve is an igniter having explosive material contained in a cover which is positioned close to the diaphragm for destruction. To adjust the performance characteristics of the explosion material is ignited in the presence of corresponding sensor data, whereby the ventilation opening is released within the pressure bottle, so that less compressed gas or generator gas can flow into the airbag.

adversely Here is the fact that through the explosive material pressures must be generated, which is substantially above the Internal pressure of the compressed gas cylinder lie to destroy the membrane. In addition, have comparatively high wall thicknesses be provided for the compressed gas cylinder to the occurring to absorb high pressure peaks without bursting.

outgoing From this prior art, the invention is based on the object To provide an inflator that is as light as possible Structure has.

According to the invention This object is achieved by an inflator with the features of Claim 1 solved. Advantageous embodiments and developments The invention are described in the subclaims.

The Inflator according to the invention for an airbag with a compressed gas storage or a pressure chamber and with a ventilation opening, which has a membrane closed and arranged on the outside of an actuator is, provides that the membrane has a gap-like outlet channel, which communicates with the ventilation opening, and a supply passage arranged adjacent to the outlet passage covering the actuator and on a web between the feed channel and the outlet channel rests. Due to the relatively narrow support surface the membrane on the bridge, the membrane through the load through pressurized the actuator on the side of the feed channel and possibly raised while the membrane over the Outlet channel is exposed to the pressure of the pressure accumulator, so that induced high voltages within the membrane in the region of the ridge which leads to breakage or failure of the membrane. The ventilation opening is released and the compressed gas in the accumulator can through the exhaust duct and the ventilation opening escape.

Of the Web can form an edge, in particular a sharp edge, around the stresses within the membrane punctiform or linear to increase. The edge can be arranged or attached to the bridge be formed so that they are only after activating the actuator comes in contact with the membrane, so that at rest one to Great load on the diaphragm is avoided when ignited z. B. a pyrotechnic propellant but a spontaneous destruction the membrane takes place.

to Training is an edge and to influence the bursting tendency it is provided that the web is oriented at an angle to the printing direction Surface has. It can also be a roof-like contour be provided on which rests the membrane, also can Bridge and thus the contact surface to the membrane rounded be formed, if this by the material properties of the Membrane is displayed.

The outlet channel is preferably annular, so that a high gas flow rate can be achieved with simultaneous simple production and easier sealability. The annular outlet channel also provides a uniform load on the membrane, since no additional edges act on the membrane and load it selectively. The feed channel is advantageously surrounded by the outlet channel, whereby the membrane is loaded symmetrically. The feed channel can be circular be formed so that a central pressure load can be exerted on the membrane. With an annular shape of the outlet channel and a round cross-section of the feed channel, the web is annular in a central arrangement of the feed channel and runs coaxially with the outlet channel and the feed channel.

In a development of the invention is the inflator than a hybrid inflator formed in which in the compressed gas storage a Gas generator is arranged or with this in fluidic Connection stands, so that if necessary an enlarged Volume of deployment gas can be introduced into the airbag. The compressed gas reservoir spontaneously releases the release gas on a relatively high level available during the Gas generator, which is usually designed as a pyrotechnic propellant is great for a long time Provides quantities of deployment gas.

A Development of the invention provides that outside the Gas cylinder a Durchringring on the outside the membrane is arranged, and at a distance, the one direct contact with a changing bulge prevents the membrane due to normal temperature fluctuations. The penetrating body on the outside of the membrane is provided as a safety device, for example in case of fire or accidental overheating the compressed gas storage provides emergency ventilation. Are the compressed gas storage tanks, possibly together with the gas generators, transported or stored, can cause temperature fluctuations or local overheating can lead to explosions, resulting in serious personal injury or material damage can lead. To the compressed gas storage as possible To vent quickly, is the Durchringring provided on the outside of the membrane.

Of the Durchdringkörper can also be movably mounted to to come into contact with the membrane. Both the penetrator as well as the membrane can be driven by the actuator and a destruction of the membrane by the immediate Effect contact with the piercing body. Is preferred the penetrator as a cone or as a cutting edge trained, another, sharp-edged design, however also possible.

Of the Actuator is in particular a pyrotechnic actuator, compressed gas storage, Projectile, mechanical energy storage or electrical discharge formed and loads the diaphragm toward the pressure gas chamber, so that the membrane is destroyed at the web.

following Embodiments of the invention with reference to the attached Figures explained in more detail. Show it:

1 - An inflator in cross section;

2a to 2c - Different states of the venting device;

3 - A variant of the invention

4 to 6 - Different web geometries.

In the 1 Fig. 12 is a cross-sectional view of a hybrid inflator 1 with a housing 2 and a gas generator 3 shown in cross-sectional view. The gas generator 3 is inside of the housing 2 formed compressed gas storage 4 or pressure chamber, is stored in the compressed gas, such as argon or compressed air. At the gas generator 3 opposite side is a venting device 5 arranged, which will be described in more detail later. At the top of the case 2 is a gas outlet 6 provided, which is a diffuser housing 7 with gas outlet openings 8th provides. Through these gas outlet openings 8th occurs in the case of triggering an ignition device 9 the compressed gas and the deployment gas and fills a gas bag, not shown.

The ignition device 9 , which is activated in the presence of appropriate sensor data, ignites that in a housing 10 arranged blowing agent 11 such that the unfolding gas formed thereby enters the pressure space 4 penetrates and there raises the internal pressure. The housing 10 is inside the pressure room 4 arranged. The deployment gas flows through openings, not shown, within the housing 10 in the pressure room 4 , An outlet channel 13 that the outlet openings 8th with the pressure room 4 is closed by a rupture disc, which breaks only at a significant pressure increase by the penetrating deployment gas.

If now a certain deployment characteristic of the airbag is to be provided, or if altered gas quantities have to be introduced into the airbag on the basis of sensor data, for example seat occupancy data, the ventilation device is activated 5 activated, which is also an ignition device 14 has, which ignites a pyrotechnic propellant. The ventilation device 5 sees an exhaust duct 21 inside the breather housing 16 in front, passing through a membrane 17 closed is. The membrane 17 prevents compressed gas from the compressed gas storage 4 through the outlet channel 21 through at least one vent 19 escapes into the environment. The vents 19 are formed as a plurality of radial outflow channels.

In the 2a is the venting device 5 with not activated ventilation in the starting position shown. Inside the case 16 a pyrotechnic propellant is arranged by the ignition device 14 is activatable. Also is a feed channel 15 in the case 16 formed by a membrane 17 is closed. Because of within the pressure chamber 4 existing pressure, the membrane bulges 17 outward into the circular feed channel 15 into it. The outlet channel 21 extends around the feed channel 15 around and forms an annular bridge 22 out, on which the membrane 17 rests. Due to the internal pressure in the compressed gas storage 4 the diaphragm bulges 17 also in the exhaust duct 21 into it.

Will now the pyrotechnic propellant through the ignition device 14 ignited, a pressure within the feed channel 15 constructed, which is greater than the internal pressure of the compressed gas storage 4 is, provided that the membrane is unloaded has a flat shape. Through the in the feed channel 15 existing pressure, symbolized by the arrows, becomes the membrane 17 towards the interior of the pressure room 4 moves and arches inwards. This situation is in the 2 B shown. The membrane 17 is from the jetty 22 partially lifted, causing the dent in the exhaust duct 21 is stronger than the 2a is. This results in the area of the outer edge of the web 22 a very high bending stress within the membrane, supported by the sudden pressure build-up by the pyrotechnic actuator, so that the membrane 17 failed. This will be the outlet channel 21 released what is in the 2c is shown. That within the pressure chamber 4 Existing compressed gas can then pass through the outlet channel 21 and a number of radia ler vents 19 out of the case 16 escape into the ambient air and the pressure level within the pressure chamber 4 reduce control.

Alternatively to the formation of the actuator as a pyrotechnic propellant charge 14 can be a loading of the membrane 17 also by an energy storage, such as a spring done biased within the housing 16 is arranged and is relaxed in the presence of corresponding sensor signals. Also, the actuator may be designed as a compressed gas storage, projectile, mechanical energy storage or electrical discharge to open the membrane.

Due to the design of the ventilation device 5 in the 2 illustrated variant, it is possible the housing 2 overall less thick to design, since upon triggering of the pyrotechnic propellant charge by the ignition device 14 the venting device 5 only about that pressure on the outside of the membrane 17 must be built in the pressure room 4 prevails because the pressure pulse pulse destruction together with the reduced contact surface on the web 22 causes.

A variant of the invention is in the 3 shown in which a Durchringringkörper 20 on the outside of the membrane 17 is arranged. The penetrating body 20 serves as an overload protection, the pressure should be within the pressure chamber 4 become too large during transport or during storage. As a result, exploding the compressed gas storage is prevented, so that damage or injury can be avoided. The penetrating body 20 can also be movably mounted.

In the 4 a variant of the invention is shown in which the venting device 5 according to the 2a to 2c is constructed. In the area of the vent 19 are filter devices 23 arranged on the radially outer periphery of the outflow channel 21 are arranged. The housing 16 the venting device 5 is in the case 2 of the printer memory and locked there. The annular bridge 22 has an inwardly tapered surface, which in the present case is oriented at an angle of approximately 45 ° to the pressure direction or to the outflow direction of the compressed gas. This creates a relatively sharp, radially outer edge of the web 22 formed on the membrane 17 is applied. In the illustrated initial state, the membrane 17 full-surface adjacent to the bridge 22 arranged and is there by the increased internal pressure of the compressed gas storage 4 held. At the radially outer edge of the bridge 22 There is a sharp deflection, so that the membrane 17 S-shaped deformed to fit in the exhaust duct 21 hineinzuwölben. The membrane 17 thus forms several concentric bulges in different directions.

Is by the ignition device 14 the pyrotechnic propellant charge is activated, as in the 2 B shown the central part of the membrane 17 bulged outward and toward the pressure gas chamber 4 relocated. Due to this bulge, the membrane 17 in the area of the outer edge of the bridge 22 break and the now slight, outer part of the membrane 17 gets into the exhaust duct 21 fold in and the channel 21 release, allowing the compressed gas from the exhaust duct 21 and through the vents 19 can flow out.

A similar representation is in the 5 shown at the slope of the sloping surface of the web 22 less than that at the 4 is. Accordingly, the membrane 17 according to 5 Weni break as fast as the membrane 4 , because due to the lower change in shape and the reduced bending angle in the region of the radially outer edge of the web 22 a lower load on the membrane 17 is exercised.

A substantially flat, so oriented almost perpendicular to the direction of pressure configuration of the surface of the web 22 is in the 6 shown, which is essentially that of 2 corresponds, but has a slight inclination radially inward. According to the 6 becomes the membrane 17 due to the larger pulse length and lower pulse height on the diaphragm 17 is exercised later break than in an embodiment according to the 4 , so that the venting behavior of the inflator through the contour of the web 22 can be changed.

The radius of the edge of the bridge 22 also acts as a seal with respect to the pressure chamber 4 when the pyrotechnic propellant of the gas generator 3 is activated and the internal pressure of the pressure chamber 4 greater than the atmospheric pressure in the exhaust duct 21 is.

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• - EP 0790157 B1 [0002]

Claims (12)

Inflation device for an airbag with a compressed gas reservoir and a ventilation opening, which is closed by a membrane, on the outside of which an actuator is arranged, characterized in that the membrane ( 17 ) a gap-like outlet channel ( 21 ) and one next to the outlet channel ( 21 ) arranged feed channel ( 15 ) of the actuator ( 14 ) and on a bridge ( 22 ) between the feed channel ( 15 ) and the outlet channel ( 21 ) rests. Inflator according to claim 1, characterized in that the web ( 22 ) forms an edge on which the membrane ( 17 ) rests. Inflator according to claim 1 or 2, characterized in that the web ( 22 ) has an oriented at an angle to the printing direction surface. Inflation device according to one of the preceding claims, characterized in that the outlet channel ( 21 ) is annular. Inflator according to one of the preceding claims, characterized in that the supply channel ( 15 ) from the outlet channel ( 21 ) is surrounded. Inflator according to one of the preceding claims, characterized in that in the compressed gas reservoir ( 4 ) a gas generator ( 3 ) is arranged or is in fluid communication therewith. Inflator according to one of the preceding claims, characterized in that the supply channel ( 15 ) has a round cross-section. Inflator according to one of the preceding claims, characterized in that the web ( 22 ) is rounded. Inflator according to one of the preceding claims, characterized in that the web ( 22 ) is annular. Inflator according to one of the preceding claims, characterized in that outside the pressure accumulator ( 4 ) a penetrating body ( 20 ) of the membrane ( 17 ) assigned. Inflator according to claim 10, characterized in that the penetrating body ( 20 ) is movably mounted. Inflator according to one of the preceding claims, characterized in that the actuator ( 14 ) is designed as a pyrotechnic actuator, compressed gas storage, projectile, mechanical energy storage or electrical discharge.