JP3633107B2 - Airbag device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an airbag apparatus for protecting an occupant by deploying an airbag in the event of a vehicle collision, and more particularly to an airbag apparatus that controls the amount of gas generation according to the collision speed.
[0002]
[Prior art]
As is well known, a vehicle airbag device includes a folded airbag, a case that accommodates the airbag, and a gas generation means for deploying the airbag, and a collision provided in the vehicle. When the detection sensor outputs a collision detection signal, the gas generating means is activated to generate gas, whereby the airbag is largely deployed in front of the occupant to protect the occupant.
[0003]
As this gas generating means, an inflator having a gas generating chemical and an igniter for igniting the chemical is widely used.
[0004]
In a widely used airbag apparatus, one or two inflators are provided. Even when two are provided, both inflators are configured to start operation simultaneously by a collision detection signal.
[0005]
JP-A-2-310143 (European Published Patent No. 399498), JP-A-4-345555, JP-A-4-345556, JP-A-7-47910, and British Patent Publication 2281429 disclose two or two stage inflators. Although an airbag device is described in which two (or two stage) inflators are operated with a time difference from each other, even in this case, all inflators are activated even if there is a time difference when a collision is detected. The point is not different from a general airbag device.
[0006]
By the way, this “activate the inflator by detecting a collision” actually means that the inflator activation signal is output when the collision scale detection system mounted on the vehicle determines that “the collision speed is greater than or equal to the threshold”. It is to be. The collision speed as the threshold is generally set to 12 mph (12 miles / Hr) for the following reason.
[0007]
In other words, when the vehicle collides, the occupant rapidly moves forward and thrusts into the airbag, but when the front of the occupant first contacts the airbag, the airbag is fully deployed (i.e., its most It is desirable that it is expanded until it is in a greatly swollen state. When designing a normal airbag, in the fully deployed state of the airbag, the occupant facing surface of the airbag and the front of the occupant body in a normal seating posture (a posture in which the occupant's back is in contact with the seat back of the seat) Care is taken to leave a 5 inch (125 mm) gap between them.
[0008]
In a general airbag device, the time from the ignition of the inflator to the completion of airbag deployment is estimated to be 30 mSec. Therefore, in the conventional airbag device, the inflator is ignited 30 mSec or more before the time required for the occupant body to move 5 inches (5 ″) after the collision, that is, the inflator. The ignition timing needs to be designed to be within (5 ″ travel time−30 mSec) from the occurrence of the collision.
[0009]
The inflator ignition timing is referred to as TTF (time to fire). Incidentally, in a general passenger car, this TTF needs to be within about 15 mSec after the collision in the case of a 30 mph (about 48 km / Hr) frontal collision for the reason described above.
[0010]
By the way, the vehicle collision speed detection system detects the acceleration applied to the vehicle from the time of the vehicle collision with time, detects the size of the collision from the change with time of the acceleration, and ignites the inflator when the collision size is equal to or greater than a predetermined value. .
[0011]
In the collision level detection system of the current technical level, for example, in the case of 30 mph frontal collision, it takes 12-14 mSec after the collision to determine that the collision speed exceeds 12 mph, and the collision speed is determined to exceed 20 mph. It takes 20-23 mSec after the collision, and 30-35 mSec to detect 30 mph. In the case of oblique collision or offset collision, the rise of acceleration is slow, and further detection takes a long time.
[0012]
As described above, the TTF is designed as (5 ″ travel time−30 mSec) before, but if it took a long time to detect the collision speed, the output of the ignition instruction signal of the inflator becomes slower than the TTF. For example, in the case of a 30 mph collision, it is necessary to ignite the inflator within 15 mSec after the collision as described above, but the collision scale detection system has not yet determined that the collision speed is 30 mph when the 15 mSec elapses. .
[0013]
Therefore, in the current airbag ignition system, when it is determined that the collision speed exceeds 12 mph (the time required to determine “more than 12 mph” is about 12 to 15 mSec after the collision as described above). Then, an airbag ignition signal is output to ignite the inflator. Thus, if the TTF is set to “at a time exceeding 12 mph”, the inflator's TTF is prevented from being slower than (5 ″ travel time−30 mSec), and whenever the occupant rushes into the airbag, the air The bag can be left fully deployed.
[0014]
FIG. 4 is a block diagram for explaining the inflator ignition timing, and shows the relationship between TTF at the time of 30 mph collision, (5 ″ travel time−30 mSec), 5 ″ travel timing, and the like.
[0015]
When 12 mSec elapses after the vehicle collides at 30 mph, it is determined that the collision speed exceeds 12 mph. At this time, an inflator ignition command is output to ignite the inflator. Then, the airbag is fully deployed at about 30 mSec. The 5 ″ movement time (the time when the occupant first contacts the deployed airbag) is after this full deployment.
[0016]
As shown, this TTF is before (5 ″ travel time−30 mSec).
[0017]
If the inflator ignition command is issued after determining that it is actually over 30 mph, as shown by the broken line in FIG. 4, the occupant rushes into the airbag before the airbag is fully deployed. It will be.
[0018]
[Problems to be solved by the invention]
As described above, in the conventional airbag apparatus, when a collision with a collision speed of 12 mph or more occurs, all inflators are operated regardless of the magnitude of the collision speed. However, when the collision speed is low, the internal pressure of the airbag does not need to be so high, and only when the collision speed is high, it is sufficient to increase the internal pressure of the airbag sufficiently.
[0019]
In view of such circumstances, an object of the present invention is to provide an airbag device in which a gas generation amount is changed according to a collision speed.
[0020]
It is another object of the present invention to provide an airbag device that increases the number of inflators that operate as the collision speed increases, and at this time, varies the operation timing of each inflator.
[0021]
[Means for Solving the Problems]
An airbag apparatus according to a first aspect of the present invention is a vehicle airbag apparatus having a folded airbag and gas generating means for inflating the airbag, wherein the seat detects whether or not the seat belt is mounted. Belt mounting detection means, collision speed detection means for detecting the collision speed of the vehicle, and gas generation amount control means for increasing the amount of gas generated from the gas generation means as the collision speed detected by the collision speed detection means increases. The gas generating means is provided with a plurality of gas generators, and the control means increases the number of gas generators that generate gas as the collision speed increases. In the case where a plurality of the gas generators are operated, the operation start timing of each gas generator is made different. That means to increase the time difference between the ignition timing of the gas generator in case of detecting the seat belt, in case of detecting the seatbelt non-wearing is to shall reduce the time difference between the ignition timing of the gas generator It is a feature .
[0022]
Airbag apparatus 請 Motomeko 2 Oite to claim 1, wherein the control means, the collision speed actuates the first when it is detected that the threshold value or more first part of the gas generator, then When it is detected that the collision speed is greater than or equal to a second threshold value that is greater than the first threshold value, another gas generator is activated.
[0023]
The airbag device according to claim 3 is a vehicle airbag device having a folded airbag and a gas generator for inflating the airbag, and seatbelt mounting for detecting whether or not the seatbelt is mounted. Detection means, collision speed detection means for detecting the collision speed of the vehicle, and gas generation amount control means for increasing the amount of gas generated from the gas generator as the collision speed detected by the collision speed detection means increases. An air bag apparatus provided, wherein the gas generator generates gas over two or more stages, and the control means controls the gas generator to operate until a later stage as the collision speed increases. When the gas generator is operated from the second stage onward, the operation start timing of each stage is made different. When the safety belt attachment detection means detects the seat belt is to increase the time difference between the ignition timing of the gas generator, in case of detecting the seatbelt non-wearing is Due to the fact that reducing the time difference between the ignition timing of the gas generator It is characterized by being.
[0024]
In the airbag device of the first to third aspects of the invention, when the collision speed is low, a smaller amount of gas is generated than when the collision speed is high, and the airbag is deployed with less gas. In the most deployed state, an airbag deployed with less gas is softer than an airbag deployed with more gas. When the collision speed of the vehicle is low, the speed at which the occupant thrusts into the airbag is small, so the occupant slowly thrusts into the soft airbag and is softly protected by the airbag .
[0025]
By varying the timing of the start of operation of the gas generator, it is possible to reduce the deployment speed of the initial deployment of the airbag.
[0026]
In the airbag device according to claim 2 , when it is determined that the collision speed is equal to or higher than the first threshold value (for example, 12 mph), for example, one gas generator is activated first, thereby starting the deployment of the airbag. To do.
[0027]
Thereafter, when it is determined that the collision speed is equal to or higher than a second threshold (for example, 20 mph), another gas generator is operated.
[0028]
If the ignition timing of all the gas generators is set as the second threshold detection timing, as described above, the TTF becomes later than the (5 ″ travel time−30 mSec) timing, and the airbag is not fully deployed. On the other hand, in the airbag apparatus according to claim 2 , when it is determined that the collision speed is equal to or higher than the first threshold, some gas generators are first activated. When the collision speed is low, the airbag is deployed only by this part of the gas generator, and when the collision speed is high, the other gas generators are also activated after that. Increase the internal pressure.Also, by operating the other gas generators, the airbag deployment speed will increase, so even if the 5 ″ travel time is advanced, the air Tsu grayed complete the well all deployment.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
The embodiment will be described with reference to FIGS. The vehicle 1 is provided with an acceleration sensor 2, a control unit 3, and an airbag device 4. The airbag device 4 may be used for a passenger seat, a driver seat, or a rear seat.
[0030]
The airbag device 4 is configured to deploy the airbag 5 with two inflators 6 and 7. When the vehicle 1 collides, the acceleration at that time is detected by the acceleration sensor 2, and the collision speed is determined from the change over time of the detected acceleration (specifically, the integrated value by the acceleration time and the differential value by the acceleration time). Is calculated by the control unit 3. The inflators 6 and 7 are operated by the control unit 3 in accordance with the magnitude of the collision speed. The acceleration sensor 2 and the control unit 3 constitute a collision speed detection system.
[0031]
The control unit 3 is configured to supply the current from the battery 8 to the igniters of the inflators 6 and 7. The control unit 3 does not operate any of the inflators 6 and 7 when the collision speed is lower than a first threshold (for example, 12 mph). When the collision speed is greater than or equal to the first threshold and less than the second threshold (for example, 20 mph), only the first inflator 6 is activated at t ₁ when it is detected that the collision speed has reached the first threshold. The second inflator is not operated. t collision speed at _one time is determined to be the first threshold value or more, when the further impact velocity at t ₂ time is determined to be equal to or greater than the second threshold value, the first inflator 6 First, at time point t ₁ is operation, and further thereafter, t ₃ at the second inflator 7 later than t ₂ is activated.
[0032]
When showing the internal pressure change of the air bag 5 when only the first inflator 6 is actuated schematically look like FIG. 3 (a), the pressure is gradually increased from time t _1. First inflator 6 is first activated, then when the second inflator 7 is operated, the internal pressure of t ₁ at the airbag 5 starts rising as shown in FIG. 3 (b), the further t ₃ at the second inflator The gas pressure from 7 is also superimposed.
[0033]
FIG. 3 (a), in either case of (b), but come plunges into the airbag 5 that the passenger 9 is deployed will later times t ₄ when the airbag 5 is sufficiently large deployment, at the t ₄ 3A and 3B, the pressure in the airbag 5 deployed only by the first inflator 6 is higher than the inner pressure of the airbag 5 deployed by both inflators 6 and 7, as is apparent from FIGS. Low. Therefore, in the case of FIG. 3A, the occupant 9 thrusts into the softer airbag 5 than in the case of FIG. However, in this case, the speed at which the occupant 9 thrusts into the airbag 5 is lower than that in the case of FIG. 3B because the collision speed of the vehicle is small, so the occupant 9 body is sufficiently protected by the soft airbag 5. Is done.
[0034]
In the case of FIG. 3B where the vehicle collides at high speed, the occupant 9 is firmly protected by the airbag 5 having a high internal pressure.
[0035]
Assuming that a passenger vehicle equipped with an airbag device 4 having two inflators 6 and 7 having substantially the same output collides with a strong concrete wall, the first threshold value is 12 mph, and the second threshold value is 20 mph. Is preferable. Further, the time difference (t ₃ −t ₁ ) of the ignition timings of the inflators 6 and 7 is preferably 10 to 30 mSec, particularly preferably 20 mSec.
[0036]
Et al is, the seatbelt, the detection means for detecting the non-wearing is provided, when the seat belt is worn is large t ₃ -t _1, when the seat belt non-attached, the t ₃ -t ₁ you small.
[0037]
In the case of FIG. 3 _(b), it is possible to reduce the deployment speed of the airbag 5 between t 1 ~t _3. Thereby, even if an occupant or an object exists in the immediate vicinity of the airbag device, the speed at which the airbag hits the object is reduced.
[0038]
The airbag device of the above embodiment includes two inflators 6 and 7, but may include three or more inflators. In this case, it is preferable that the number of inflators to be operated is 0, 1, 2, 3 or more according to the collision speed. When two or more inflators are operated, the operation start timing of each inflator is shown in FIG. It is preferable to shift as shown in b). When operating three or more inflators at different timings, for example, one inflator is operated at 12 mph, another inflator is operated at 20 mph, and the remaining inflators are operated at 30 mph.
[0039]
In the present invention, one inflator may generate gas over two or more stages, and gas generation after the second stage may be stopped by a signal from the control unit.
[0040]
【The invention's effect】
As described above, the present invention controls the inflator according to the collision speed of the vehicle, and can protect the occupant with a soft airbag with low internal pressure when the vehicle collides at a low speed. In high-speed collisions, the air bag with high internal pressure can protect the occupant firmly . According to the airbag device of the present invention, the deployment speed of the airbag immediately after the start of deployment can be reduced.
[Brief description of the drawings]
FIG. 1 is a side view of a vehicle equipped with an airbag device according to an embodiment.
FIG. 2 is a system diagram of the airbag apparatus according to the embodiment.
FIG. 3 is a time-dependent change diagram of the pressure inside the airbag showing the operation of the airbag apparatus according to the embodiment.
FIG. 4 is a graph showing the relationship between inflator ignition timing and airbag internal pressure.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Vehicle 2 Acceleration sensor 3 Control unit 4 Air bag apparatus 5 Air bag 6, 7 Inflator 8 Battery

Claims (3)

In a vehicle airbag apparatus having a folded airbag and gas generating means for inflating the airbag,
Seat belt wearing detection means for detecting whether or not the seat belt is worn;
A collision speed detecting means for detecting a collision speed of the vehicle;
An air bag apparatus provided with a gas generation amount control means for increasing the gas generation amount from the gas generation means as the collision speed detected by the collision speed detection means increases.
The gas generating means includes a plurality of gas generators,
The control means increases the number of gas generators that perform gas generation and operation as the collision speed increases. Further, when the seat belt attachment detection means detects seat belt attachment, the time difference of the ignition timing of the gas generator is increased, and when detection of seat belt non-attachment is detected, the ignition timing of the gas generator is increased. airbag apparatus which is a small to shall the time difference. Large Oite to claim 1, wherein the control means activates the when is detected first portion of the gas generator that impact speed is equal to or greater than the first threshold, thereafter collision speed than the first threshold value An air bag device that activates another gas generator when it is detected that the second threshold value is exceeded. In a vehicle airbag apparatus having a folded airbag and a gas generator for inflating the airbag,
Seat belt wearing detection means for detecting whether or not the seat belt is worn;
A collision speed detecting means for detecting a collision speed of the vehicle;
An air bag apparatus provided with a gas generation amount control means for increasing the gas generation amount from the gas generator as the collision speed detected by the collision speed detection means increases.
The gas generator generates gas over two or more stages,
The control means controls the gas generator so that the gas generator operates until the later stage as the collision speed increases. When the gas generator is operated until the second stage and thereafter, the operation start timing of each stage Further, when the seat belt wearing detection means detects seat belt wearing, the time difference of the ignition timing of the gas generator is increased, and when the seat belt non-wearing is detected, the gas generator airbag and wherein the of a small to shall the time difference of the ignition timing.

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