DE102007031913A1 - Airbag module for motor vehicle, has control device activating gas generator so that gas generator fills airbag in one of time periods, as soon as collision early recognition unit detects upcoming collision of motor vehicle - Google Patents

Abstract

The module has a multi-stage gas generator (1) for filling an airbag with gas alternatively in two time periods. A control device activates the gas generator in such a manner that the gas generator fills the airbag in one of the time period as soon as a collision detection unit detects a collision of a motor vehicle. Another control device activates the gas generator in such a manner that the gas generator fills the airbag in other time period, as soon as a collision early recognition unit detects an upcoming collision of the motor vehicle. An independent claim is also included for a method for filling an airbag of an air bag module.

Description

The The present invention relates to an airbag module according to the preamble of claim 1 with an air bag and a method for filling the airbag of such an airbag module.

One Airbag module for a motor vehicle generally includes a Airbag and a gas generator for filling the airbag with a gas. In case of a collision of the motor vehicle generates the gas generator is a rapidly expanding gas and fills with it the airbag. This then expands greatly and forms a baffle for a vehicle occupant. Such Airbag modules can equally protect a Driver or passenger of the motor vehicle to be provided and For example, in a steering wheel, a dashboard, a A, B or C pillar, a door or a roof area be arranged of the motor vehicle. Preferably, the airbag folded small in the initial state and behind a panel which he breaks through as he unfolds.

From the US 5,346,254 is an airbag module according to the preamble of claim 1 for a motor vehicle with a two-stage gas generator for filling the airbag with a gas known. The two-stage gas generator comprises a gas generating agent in the form of gas-filled tablets which can be ignited by a first and a second ignition charge to produce the gas for filling the airbag.

As soon as a collision detection device a collision of the motor vehicle has detected, the first and second ignition means are simultaneously ignited. This builds up a big explosion pressure which severely disassembles the Gassatz tablets and thus their surface significantly enlarged. Because of this clearly enlarged surface that reacts Gas generating agent stronger and faster and generates so quickly a large volume of gas with which it is the airbag filled in a first, short period of time.

Such however, high filling rates entail one Series of risks. This creates a strong sound pressure, which can damage the eardrum of the occupants. moreover the unfolding airbag hits the vehicle occupants with high momentum and can cause injury, especially if this have leaned against the airbag and therefore early in the filling phase of which is with big Balancing unfolding airbag are taken.

Therefore, the beats US 5,346,254 to sequentially ignite the first and second ignition means when the subject vehicle occupant is in an out-of-position position during the collision, or because of the vehicle deceleration it is determined that it is a slight, low-hazard collision. As a result, the gas generating agent is not decomposed so much, it responds accordingly weaker and in particular slower, so that the gas is generated at a lower gas generation rate and fills the air bag in a second period, which is longer than the first period. This reduces the above-mentioned dangers if the collision is not so severe or the vehicle occupant is already closer to the airbag module, for example.

Similarly, the US 5,460,405 to ignite only a portion of the existing ignition means when a vehicle occupant is in an out-of-position position during the collision. The US 5,221,109 stimulates to ignite a second ignition means during the filling process, thereby diverting generated gas to the environment instead of the airbag and thus reducing its inflation power and in particular the amount of gas charged, if it is determined that the collision is of lesser severity.

According to the prior art, however, the filling of the airbag is always initiated as soon as a collision detection device has detected a collision of the motor vehicle. Thus, there is only a relatively short first period available for the filling and deployment of the airbag. For example, as in 2 2, a collision occurs at time tc and is subsequently detected at time tr by the collision detection device, the airbag must be completely filled in the short period of time t100-tr in order to absorb the vehicle occupants approaching in time and sufficiently due to the inertial forces. At today's reaction times of about 20 to 40 ms between collision tc and their detection tr by the collision detection device remain, for example, only 20 to 40 ms for filling the airbag until the vehicle occupant must be collected at t100 through the air bag before passing through parts of the passenger compartment or a restraint device would be injured.

Even if, for example, in the US 5,346,254 proposed the airbag deployment is slowed down in an out-of-position position or a lighter collision, the filling process continues to happen only in the relatively short period between detection of the collision and the necessary interception of the Vehicle occupants.

These short periods of time, the above dangers pose a risk Injury to the vehicle occupants by the rapidly and accordingly with great force unfolding airbag, which only in purchase is taken to sever heavier injuries by clashing with Sharing the passenger compartment or a restraint system to avoid or reduce.

task The present invention is therefore the risk of injury to reduce by a rapid deployment of the airbag.

These The object is solved by the features of claim 1 and 10, respectively. Advantageous embodiments of the invention are the subject the dependent claims.

One Airbag module for a motor vehicle comprises according to the present Invention an air bag and a multi-stage gas generator for Fill the airbag with a gas. The gas generator Can the airbag either in a first period or in a second, longer period to fill.

For this purpose, the gas generator may have, for example, a first and a second ignition means for igniting a gas generating agent. In order to fill the airbag in the first, shorter period, then, for example, the stronger first ignition means and, preferably, the second, weaker ignition means can be ignited simultaneously or sequentially. Like in the US 5,346,254 and the US 5,460,405 , the disclosure of which is hereby expressly incorporated into the present application, explained in detail, the gas generating agent can be ignited more vigorously and quickly, especially over a large area and react so that it generates gas with a high gas generation rate and the air bag quickly in the first, shorter period filled.

As shown in detail in the cited documents, can be varied while the first, shorter period, by, for example, optionally the first or the first and the second ignition means, both ignition means optional simultaneously or sequentially and / or further ignition means to be detonated. As a result, in a preferred embodiment the inflation time can still be varied within the first period. For example, the inflation time may be increased by, preferably simultaneously, Igniting several ignition means are shortened when a heavy collision and / or a far from unfolding Airbag remote vehicle occupant is detected. Conversely, can by sequentially igniting the ignition means and / or Igniting only part of the existing ignition means, in particular only the first ignition means the inflation time of the airbag is extended within the first period become.

For example The airbag may be in a slight collision and / or an out-of-position Position of the vehicle occupant within about 40 to 50 ms, otherwise within about 20 to 30 ms completely filled. The first period is therefore in a preferred embodiment at most 50 ms, preferably at most 40 ms, further preferably at most 30 ms and more preferably at most 20 ms.

The explained above filling the airbag within the first period thus takes place in per se known Way, once a collision detection device collides of the motor vehicle has detected by a first control device activated the gas generator accordingly. The collision detection device can detect, for example, a collision of the motor vehicle, as soon as a longitudinal and / or lateral acceleration reaches a certain Exceeds limit. This is preferably chosen so that he did not exceed the driver at a deceleration of the motor vehicle but only in the event of a collision, so the abrupt deceleration the motor vehicle through an obstacle. Additionally or Alternatively, for example, deformation sensors can be an incipient Detecting deformation of the vehicle body in a collision.

According to the invention now additionally provided a second control device, which activates the gas generator such that it the airbag in a second, longer period filled as soon as one Collision early detection device an upcoming Collision of the motor vehicle has detected.

Such a collision early detection device may include, for example, an environment detection device for detecting an environment before, next to and / or behind the motor vehicle, which detects a relative distance and / or a relative speed between an object in the environment and the motor vehicle and at low relative distance and / or greater approach speed between Object and motor vehicle on an imminent collision closes. Likewise, the collision detection device may have a communication device through which it can communicate with other vehicles and exchange the respective vehicle positions so that it can deduce an imminent collision from the received and own vehicle positions. Additionally or alternatively, the collision early detection device, for example, from a delay that is caused by very strong braking by the driver to conclude that the driver has detected an imminent collision. Of course, other collision early detection devices are usable.

Thereby, that the gas generator already by the second control device can be activated as soon as in advance of a collision, so still before this occurs, an imminent collision is detected, magnified itself for filling the airbag available standing period significantly. Therefore, the airbag according to the invention in be filled for a second, longer period, as soon as an imminent collision by the collision early detection device has been recognized. Due to the slower filling and Unfolding of the airbag in the second, longer period the dangers of injury to the vehicle occupants are reduced. In particular, only a lower sound pressure occurs and the airbag hits the vehicle occupants with a lower impulse.

It However, collisions may occur that are caused by the collision early detection not be recognized in advance in advance. For example, can a motor vehicle whose collision early detection device monitors the environment in front of the vehicle, be hit laterally by another motor vehicle, without that the collision early detection device in time detects before the collision. It is also possible that obstacles, for example, as a result of a rockfall, abruptly before Emerge motor vehicle and collide with this, without them previously detected by the collision early detection device have been. The motor vehicle can, for example, with others Road users collide suddenly from the side entering the front area in front of the motor vehicle and in succession the previous of the collision early detection device have not been recognized.

In In this case, it is necessary to deploy the airbag quickly. Therefore is according to the invention in addition to the second control device Furthermore, the first control device is provided, which the gas generator activated so that it the airbag in the first, shorter Period filled in case a collision occurs that is not in the Apron detected by the collision early detection device i. e. without the airbag in the second, longer Period has been unfolded.

These two-stage activation of the gas generator is also advantageous if the period between the collision early detection and the actual collision unexpectedly shortened, so that the airbag that is filled as soon as the impending Collision has been detected, not in time completely would be filled.

Prefers Thus, the first control device can then also the gas generator (additionally) activate as soon as a collision is detected has been, even if this already by the second control device has been activated. This allows the gas generator in the last Stage of filling reinforced filled become. Alternatively, the second control device activation also prevent the gas generator by the first control device as soon as the collision early detection device an impending Collision has detected, since in this case sufficient filling the airbag already ensured by the second control device is.

By the detection of an imminent collision by the collision early detection device can the second period for filling the airbag clearly be enlarged. He can, for example, at least 80 ms, preferably at least 100 ms, more preferably at least 200 ms and more preferably at least 500 ms. If sufficient reliable and far-reaching collision detection can The second period will also be extended beyond that and, for example, 1000 ms. In particular, the reaction time can be tr - tc, so far between the collision and its detection passed by the collision detection device, with used become.

By this extension of the period for filling the airbag, the deployment can be done gently. simultaneously advantageous already an early connection the vehicle occupant to the unfolding airbag and reduced so on the risk of injury.

Further yield advantageous developments of the present invention from the subclaims and the description below preferred embodiments. This shows, partially schematized:

1 a gas generator of an airbag module according to an embodiment of the present invention; and

2 the filling of the airbag of the airbag module after 1 over time t.

In 1 is schematically a gas generator 1 an airbag module according to an embodiment of the present invention. This comprises a gas generating agent in the form of a plurality of gas kit tablets 2 in a housing 3 are received and a first ignition 30 and a second ignition means 40 partially surrounded. The first ignition 30 includes a first squib 32 that in a first, larger booster chamber 31 is included. Similarly, the second ignition means comprises 40 a second booster chamber 41 in which a second squib 42 is included. Here is the second booster chamber 41 smaller than the first booster chamber 31 ,

Will be the first squib 32 ignited by a first (not shown) control device, her explosion pressure is through the larger first booster chamber 31 Strengthens and disassembles the Gassatz tablets 2 into smaller fragments so that they react on a larger surface and generate gas with a high gas generation rate, that is, a large volume of gas generated per unit time. This gas passes through filter cloth 4 from outflow openings 5 in a (not shown) initially folded air bag and fills it. The airbag unfolds to catch a vehicle occupant.

Once a collision detection device (not shown) detects a weak collision by a deceleration detector (not shown) determining that a vehicle longitudinal deceleration exceeds a predetermined first limit greater than the maximum achievable deceleration by braking the vehicle, the first controller activates the inflator by putting the first squib 31 is ignited. As a result, ignites the first ignition means 30 the gas kit tablets 2 , which generate gas and fill the airbag in a first period of 40 ms.

On the other hand, if the collision detecting device detects a severe collision, for example, the deceleration detecting device detects a deceleration exceeding a third threshold which is greater than the first threshold and is achieved, for example, only when the motor vehicle is impacted by a high-speed obstacle Collision with an obstacle, which has moved at an opposite speed to the motor vehicle, is reached, the first control device ignites simultaneously the first and second squib 32 . 42 , This will cause the gas kit tablets 2 decomposed into even smaller fragments, that is, their surface on which they react, increased even more, so that generates gas with a higher gas generation rate and the airbag is filled in a first period of 20 ms.

If a collision early detection device (not shown) has already recognized in advance that a collision is imminent, a second control device (not shown) activates only the second ignition means 40 that means ignites the second squib 42 in the smaller booster chamber 41 , As a result, the Gassatz tablets are only slightly disassembled and thus react only on a small surface. This gas is generated with a low gas generation rate and fills the airbag in a second, longer period of 150 ms. The airbag unfolds slower and smoother, so that the generated sound pressure is lower and the risk of eardrum injury of the passengers is reduced. At the time of the collision, the airbag is already partially deployed, so that it comes to an early connection of the vehicle occupant, which move towards the airbag, which further reduces the risk of injury.

This process is in 2 shown graphically. At time tc, the vehicle collides with an obstacle. Basically, after approximately 20 ms, that is to say at time t r, the collision detection device detects the collision on the basis of the resulting deceleration of the vehicle and, as explained above, ignites the first ignition means 30 , Within another 40 ms, the gas generator fills the airbag, which has thus fully deployed 60 ms after the collision (t100).

However, if the imminent collision is detected early in advance, for example at time tp 90 ms before the actual collision tc, the second control device ignites the second ignition means at this point in time 40 , As a result, gas is generated with a lower gas generation rate, so that the airbag fills within 150 ms. As with the activation described above after detection of the collision, the airbag is completely filled at time t100 and develops its full protective effect. At the same time it has, in particular, from the slope of the degree of filling F over the time t in 2 can be seen over the period t100 - tp, that is in 150 ms and thus developed more slowly. In order to reduces the risk of injury to vehicle occupants.

If the collision detection device detects a severe collision, the airbag must be completely filled at an earlier point in time t100 'in order to catch the rapidly approaching vehicle occupant in a timely manner. For this purpose, as explained above, the first and second ignition means 30 . 40 ignited simultaneously. How out 2 is apparent, even in the case of such a serious collision, the airbag due to the release of the collision early detection device is already substantially filled. The ignition signal of the first control device, which is simultaneously connected to the first and second squibs ( 32 . 42 ) is fired, then ignites the not yet activated first squib ( 32 ), which accelerates the filling process of the airbag in the last section and thus ensures that the airbag is completely filled at time t100 '. However, even without this additional activation, the airbag filled by the gas generator, which was activated by the second control device, would already be largely filled at time t100 'and would exert a sufficient protective effect.

If a collision occurs that was not detected by the collision early detection device at time tc, for example because a vehicle has entered the front of the vehicle from the side and could not be detected in time by an environment detection device, the first control device activates in the manner described above the first and possibly the second ignition means 30 . 40 , so that even in this case, a filling of the air bag is ensured until the time t100 or t100 '. LIST OF REFERENCE NUMBERS 1 inflator 2 Gas charge tablets 3 casing 4 filter 5 outflow 30 First ignition 31 Booster chamber 32 squib 40 Second ignition 41 Booster chamber 42 squib tp Time of collision early detection ("precrash") tc Time collision tr Time collision detection ("reaction") t100 ' Time full filling (heavy collision) t100 Time complete filling (slight collision) F fill factor

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - US 5346254 [0003, 0006, 0009, 0014]
• - US 5460405 [0007, 0014]
• - US 5221109 [0007]

Claims (12)

Airbag module for a motor vehicle, with an airbag; a multi-stage gas generator ( 1 ) for filling the airbag with a gas, wherein the gas generator optionally fills the airbag in a first period (t100-tr; t100'-tr) or in a second period (t100-tp) longer than the first period (t100-tp). tr; t100 '- tr); a first control device for activating the gas generator ( 1 ) in such a way that it fills the airbag in the first period (t100-tr; t100'-tr) as soon as a collision detection device has detected a collision of the motor vehicle, characterized by a second control device for activating the gas generator ( 1 ) such that it fills the airbag in the second period (t100 - tp) as soon as a collision early detection device has detected an imminent collision of the motor vehicle. Airbag module according to claim 1, according to claim 1, characterized characterized in that the first period (t100 - tr; t100 '- tr) at most 50 ms, preferably at most 40 ms, further preferably at most 30 ms and more preferably at most 20 ms. Airbag module according to one of the preceding claims, characterized in that the second period (t100 - tp) at least 80 ms, preferably at least 100 ms, more preferably at least 200 ms and more preferably at least 500 ms. Airbag module according to one of the preceding claims, characterized in that the collision detection device a delay detecting means to a Collision of the motor vehicle to detect, as soon as a delay of the motor vehicle exceeds a certain first limit. Airbag module according to one of the preceding claims, characterized in that the collision early detection means a communication device for communication with other vehicles, to detect an impending collision of the motor vehicle, once the communication device becomes an illegal approach of another vehicle. Airbag module according to one of the preceding claims, characterized in that the collision early detection means an environment detection device for detecting an environment before, next to and / or behind the motor vehicle has to face an imminent To detect collision of the motor vehicle, as soon as the environment detection device an improper approach to an object in the vehicle environment detected. Airbag module according to one of the preceding claims, characterized in that the collision early detection means a delay detecting means to a recognize imminent collision of the motor vehicle as soon as possible a delay of the motor vehicle a certain second Exceeds limit. Airbag module according to one of the preceding claims, characterized in that the multi-stage gas generator ( 1 ) a gas generating agent ( 2 ) which generates gas after ignition and a first and a second ignition means ( 30 . 40 ) for igniting the gas generating agent ( 2 ), wherein the first control device, the first ignition means ( 30 ) or the first and second ignition means ( 30 . 40 ), simultaneously or sequentially, and wherein the second control means only the second ( 40 ) Can activate the ignition means. Airbag module according to claim 8, characterized in that the first control device, the first ignition means ( 30 ) is activated when the collision detection device has detected a slight collision of the motor vehicle, and the first and second ignition means ( 30 . 40 ), simultaneously or sequentially, activated when the collision detection device has detected a heavy collision of the motor vehicle. Method for filling the airbag of an airbag module according to one of the preceding claims with a gas, comprising the steps - activating the gas generator ( 1 ) by the second control device such that it fills the airbag in the second period (t100 - tp) as soon as a collision early detection device has detected an imminent collision of the motor vehicle; - activation of the gas generator ( 1 ) by the first control means such that it fills the airbag in the first period (t100 - tr; t100 '- tr) as soon as a collision detection device has detected a collision of the motor vehicle. Method according to claim 10, characterized in that in that the second control device activates the gas generator prevented by the first control device when a collision early detection device an imminent collision of the motor vehicle has detected. Method according to claim 10, characterized in that that the first control device in addition to the gas generator to the second controller and a gas generation rate of the gas generator increases when the collision early detection device an imminent collision of the motor vehicle has detected, as soon as the collision detection device a collision of the motor vehicle has recorded.