JP3870837B2 - Airbag device for automobile head protection - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an airbag device for protecting a head of an automobile.
[0002]
[Prior art]
A side roof rail is arranged at a position higher than the occupant's head in the body of an automobile, and an airbag device for protecting the occupant's head during rollover is provided along this side roof rail (similar technology, JP, 2001-260802, A).
[0003]
In this type of airbag device, the upper end portion is fixed to the side roof rail, the whole is folded and stored in the vertical direction, and the airbag at a position corresponding to an occupant seated on the seat is from the inflator. It is a structure that descends in the form of a curtain while expanding from the top to the bottom by the jet gas.
[0004]
[Problems to be solved by the invention]
However, in such a conventional technology, acceleration is applied in the lateral direction of the automobile, the occupant approaches the interior wall of the automobile, and the occupant enters the airbag deployment area. If the curtain airbag is deployed when the gap between the interior side walls, for example, the door glass and the pillar trim is small, the deployed curtain airbag may be deployed on the interior side of the occupant's head. There is a risk of giving.
[0005]
The present invention has been made paying attention to such a conventional technique, and is intended for protecting the head of an automobile in which the curtain airbag is not deployed indoors from the passenger's head when the curtain airbag is deployed. A bag device is provided.
[0006]
[Means for Solving the Problems]
The invention according to claim 1 is folded and stored in a state where the upper end portion is fixed to the upper part of the vehicle body at a position higher than the head of the occupant, and is curtained toward the lower side when the vehicle rolls over. An airbag device for protecting the head of an automobile equipped with an airbag to be deployed to the vehicle, and immediately before the curtain airbag is deployed, the lateral acceleration applied to the automobile is integrated to estimate the movement locus of the occupant's head Then, the distance between the occupant's head and the interior side wall is detected from the movement locus, and if the distance is smaller than the width in the vehicle width direction when the curtain airbag is deployed, the inflation and deployment of the curtain airbag is prohibited.
[0007]
According to the curtain airbag of the first aspect of the present invention, when the distance between the occupant head and the interior side wall is smaller than the width in the vehicle width at the time of deployment of the curtain airbag immediately before deployment of the curtain airbag, Since the inflating and deploying of the curtain airbag is prohibited, it is possible to prevent an uncomfortable feeling caused by deploying from the passenger to the indoor side. In other words, since the curtain airbag enters between the occupant head to be protected and the side wall of the automobile interior, it is possible to absorb an impact force such as a secondary collision of the occupant.
[0008]
According to the first aspect of the present invention, the lateral acceleration applied to the automobile is integrated to estimate the movement locus of the occupant head, and the distance between the occupant head and the indoor side wall is detected from the movement locus.
[0009]
According to the first aspect of the present invention, since the movement trajectory of the occupant's head is estimated, the detection of the distance between the occupant and the interior side wall is more accurate, and the curtain airbag is located between the occupant head and the interior side wall. It can be surely inflated and deployed.
[0010]
The invention according to claim 2 estimates the roll angle of the vehicle from the roll angular velocity of the vehicle, and detects the distance between the passenger's head and the indoor side wall from the size of the roll angle.
[0011]
According to the invention described in claim 2 , since the roll angle of the vehicle is estimated from the roll angular velocity of the vehicle, the detection of the distance between the occupant and the interior side wall is more accurate, and the curtain airbag is It is possible to inflate and deploy reliably.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
A preferred embodiment of the present invention will be described below with reference to FIGS.
[0013]
FIG. 1 is a diagram for explaining the relationship between the roll angle θ and the roll angular velocity ω and the rollover possibility of the automobile 1. The automobile 1 is rolled from FIG. 1A, and the center of gravity position Mg of the automobile 1 is outside the roll. The state of lifting up to a point on the vertical line passing through the tire 8 (FIG. 1B) is the static rollover limit (SSA), and even if the roll angular velocity ω is almost zero, this static rollover limit. When the roll angle θ is larger than (SSA), the automobile 1 rolls over due to gravity.
[0014]
FIG. 2 is a two-dimensional map showing the possibility of rollover of the automobile 1. The roll angle θ on the vertical axis corresponds to the right roll angle with a positive value (above the origin), and the roll angular velocity ω on the horizontal axis is positive. The value (on the right side of the origin) corresponds to the right roll angular velocity. In this two-dimensional map, a threshold value line S consisting of a straight line descending to the right is set, and the origin side of the threshold value line S, that is, the region where the roll angle θ and the roll angular velocity ω are small is set as a non-rollover region. The opposite side of the value line S, that is, the region where the roll angle θ and the roll angular velocity ω are large is defined as a rollover region. When the history lines H1 to H3 of the actual roll angle θ and the roll angular velocity ω of the automobile 1 cross the threshold value line S from the non-rollover area on the origin side to the rollover area on the counter-origin side, the rollover possibility of the automobile 1 may occur. It is determined that there is.
[0015]
The history line H1 is a case where only the roll angle θ is slowly increased from the state where the roll angle θ and the roll angular velocity ω are both zero (origin) while the roll angular velocity ω is substantially zero, and the threshold value line. When the roll angle θ reaches the critical roll angle θCRIT at the point where S intersects the vertical axis, it is determined that the automobile 1 may roll over. At this time, the center-of-gravity position Mg of the automobile is on a vertical line passing through the tire 8 on the outer side in the roll direction serving as a fulcrum of rolling, and this state becomes a static stability limit for the rollover of the automobile 1. The value of the critical roll angle θCRIT varies depending on the shape of the automobile and the loading state, but is generally about 50 degrees.
[0016]
Even if the roll angle θ is zero, the automobile 1 may roll over if a large roll angular velocity ω is acting. The roll angular velocity ω at this time is defined as a critical roll angular velocity SSA.
[0017]
When the automobile 1 has a roll angular velocity ω in the same direction as the roll angle θ, the roll angular velocity ω tends to promote rollover. Therefore, the roll angle θ is smaller than the critical roll angle θCRIT. Will roll over. For example, when the history line of the roll angle θ and the roll angular velocity ω is indicated by H2 or H3, the automobile 1 may roll over at a point where the history line H2 or H3 crosses the threshold value line S from the origin side to the non-origin side. It is determined that there is. At this time, the roll angle θ is smaller than the critical roll angle θCRIT.
[0018]
FIG. 3 is a diagram showing the behavioral relationship between the automobile 1 and the head 7a of the occupant 7 over time. FIG. 3A shows the relationship with the roll angle θ, and FIG. 3 (c) shows the relationship with the lateral acceleration Y-G applied to the automobile 1, and FIG. 3 (d) shows the head 7a of the occupant 7 and the indoor side wall of the automobile 1. And clearance. That is, when the lateral acceleration Y-G is applied to the occupant, the head 7a of the occupant 7 is initially separated from the indoor side wall 9 of the automobile 1 (primary collision), and a secondary collision load is applied, so that the occupant 7's head This means that 7a is close to the indoor side wall 9 of the automobile 1 and leaves again.
[0019]
FIG. 4 shows a control system for deploying a curtain-like airbag 2 (hereinafter simply referred to as a curtain airbag) 2 that protects the head 7 a of the occupant 7 when the automobile 1 rolls over along the indoor side wall 9 of the automobile 1. An example is shown. The curtain airbag 2 is folded and housed in the vertical direction with the upper end fixed to the upper part of the side roof rail at a position higher than the head 7a of the occupant 7, and the vehicle 1 rolls over. Sometimes, the gas of the inflator is guided to be developed in a curtain shape downward.
[0020]
An example of the control system will be described. The electronic control unit 3 has an acceleration in the lateral direction of the vehicle body, that is, whether or not the vehicle 1 is likely to roll over and whether or not the curtain airbag 2 is actuated is determined. A signal from the lateral acceleration sensor 4 that detects the lateral acceleration YG and a signal from the roll angular velocity sensor 5 that detects the roll angular velocity ω of the automobile 1 are input. First, the lateral acceleration sensor 4 fixed to the vehicle body outputs the lateral acceleration YG when the ignition switch is turned on. When the ignition switch is turned on, the vehicle 1 is in a stopped state, so the lateral acceleration Y-G caused by the centrifugal force associated with the turning of the vehicle 1 is not detected, and the vehicle body left-right direction with gravity acceleration G = 1. Is detected as the lateral acceleration YG. Therefore, the initial value θi of the roll angle θ of the automobile 1 can be calculated by θi = sin ⁻ 1YG using the lateral acceleration YG.
[0021]
As described above, when the initial value θi of the roll angle θ of the automobile 1 is calculated based on the output of the lateral acceleration sensor 4 when the ignition switch is turned on, the variation of the roll angle θ is added to the initial value θi. Is added to calculate the roll angle θ of the automobile 1. That is, from the time when the ignition switch is turned on, the integrated value ∫ωdt of the roll angular velocity ω of the vehicle 1 output from the roll angular velocity sensor 5 is added to the initial value θi as a variation of the roll angle θ, thereby The angle θ is calculated.
[0022]
The lateral acceleration sensor 4 cannot detect the lateral acceleration Y-G when the automobile 1 is free-falling, and the lateral acceleration Y-G caused by the centrifugal force accompanying the turning of the automobile 1 Although it has a demerit that it cannot be distinguished from the lateral acceleration YG that is a component of the direction and is erroneously detected, the lateral acceleration YG output by the lateral acceleration sensor 4 is turned on when the ignition switch is turned on. Is used only for calculating the initial value θi of the roll angle θ of the automobile 1, and the roll angle θ of the automobile 1 is calculated by using the integral value ∫ωdt of the roll angular speed ω of the automobile 1 output from the roll angular velocity sensor 5. By using it, the above disadvantages can be eliminated and an accurate roll angle θ can be calculated.
[0023]
The above operation will be described with reference to the flowchart shown in FIG. In step 1, the roll angular velocity ω and the lateral acceleration YG of the vehicle 1 are read, and in step 2, the threshold value lines S and S on the map are determined according to the lateral acceleration YG. The threshold lines S and S are determined if the critical roll angle θCRIT intersecting the vertical axis of the map and the critical roll angular velocity ωCRIT intersecting the horizontal axis are determined. In this embodiment, when the rollover of the vehicle 1 is promoted by the lateral acceleration YG, both the critical roll angle θCRIT and the critical roll angular velocity ωCRIT are decreased and the threshold lines S and S move in the direction approaching the origin. When the rollover of the automobile 1 is suppressed by the lateral acceleration YG, the critical roll angle θCRIT and the critical roll angular velocity ωCRIT both increase and the threshold value lines S and S move in the direction away from the origin. Thereby, an appropriate rollover region and a non-rollover region can be set according to the lateral acceleration YG of the automobile 1.
[0024]
Subsequently, it is determined whether the coordinate point formed by the current roll angle θ1 and roll angular velocity ω1 is in the rollover region or the non-rollover region. That is, in step 3, the determination value ωS is calculated by substituting the current roll angular velocity ω1 for the roll angular velocity ω in the threshold value line equation. In Step 4, the determination value ωS is compared with the current roll angle θ1, and if the roll angular velocity ω is larger than the determination value ωS, the process proceeds to Step 5 and it is determined that the vehicle is in the rollover region. 6 calculates the distance in the left-right direction (D in FIG. 8) between the head 7a of the occupant 7 and the indoor side wall 9 such as the roof lining or door window panel from the left-right position of the head 7a of the occupant 7 detected in FIG. The distance D is compared with a preset threshold value Dmin. The threshold value Dmin is set as a width in the vehicle width direction (minimum distance) for preventing the curtain airbag from interfering with the head 7a of the occupant 7 even if the curtain airbag is deployed.
[0025]
In this way, if the left-right distance D between the head 7a of the occupant 7 and the interior side wall 9 such as roofing or door window panel is equal to or greater than the threshold value Dmin in step 6, the process proceeds to step 7 and the curtain The airbag 2 can be inflated and deployed so that the head 7 a of the occupant 7 does not interfere with the indoor side wall 9 when the automobile 1 rolls over. On the other hand, in Step 4, the determination value ωS is compared with the current roll angle θ1, and if the roll angular velocity ω is smaller than the determination value ωS, the process proceeds to Step 8, and it is determined that the vehicle is in the non-rollover region. Supplying gas to the curtain airbag 2 is prohibited and the curtain airbag 2 is disabled. In step 6, if the distance D in the left-right direction between the occupant's head and the interior side wall 9 such as roofing or door window panel is less than the threshold value Dmin, the curtain air bag 2 is deployed and the curtain air It is estimated that the bag 2 is not more than the width in the vehicle width direction (minimum distance) that does not interfere with the head 7a of the occupant 7, and the process proceeds to step 9 to prohibit the supply of gas to the curtain airbag 2, Interference between the head of the occupant and the curtain airbag 2 is prevented.
[0026]
FIG. 6 shows the relationship between the behavior of the head 1a of the automobile 1 and the occupant 7 and the lateral acceleration YG to be integrated. That is, as shown in FIG. 6A, when the lateral acceleration YG is equal to or less than a certain value G1 (for example, 0.3 G), neither the car 1 nor the head 7a of the occupant 7 moves. Next, as shown in FIG. 6B, when the lateral acceleration Y-G is a constant value G2 (eg, 1.1 G) higher than the constant value G1, the car 1 does not lift the tire 8, The head 7a of the occupant 7 moves in a direction to which the lateral acceleration YG is applied (referred to as a secondary collision). Then, as shown in FIG. 6C, when the lateral acceleration YG is higher than a certain value G2, the tire 8 of the automobile 1 tilts so as to float, and the head 7a of the occupant 7 has the lateral acceleration YG. It is pressed by the direction in which is added. The relationship between the lateral acceleration YG and the behavior of the head 7a of the occupant 7 is that the movement locus of the head 7a of the occupant 7 is obtained by integrating only the lateral acceleration YG in FIG. Is estimated and is shown in FIG. In FIG. 9, the solid line indicates the actual movement locus of the head 7a, the thin line indicates the movement locus with a limited integration range, and the dotted line indicates the movement locus obtained by integrating all. The distance between the head 7a of the occupant 7 and the indoor side wall 9 is detected from this movement locus. Also, in the event that the lateral acceleration YG is continuously applied, such as steady circle turning, the integrated value accumulates and the error becomes large. Therefore, the malfunction is prevented by limiting the integration time (for example, 200 mmsec). It can be done.
[0027]
FIG. 10 is another embodiment of the present invention, and is an example in which the roll angular velocity ω of the automobile 1 by the roll angular velocity sensor 5 is used to calculate the movement trajectory of the head 7 a of the occupant 7. According to this embodiment, as shown in FIG. 8B, when a large roll angular velocity ω is generated, the occupant 7 behaves to return to the original position by inertia, and therefore the distance D tends to increase. As shown in FIG. 8 (a), when a small roll angular velocity ω is generated, the occupant 7 tends to approach the side surface 9 of the interior of the automobile 1 due to gravity. The movement trajectory of the head 7a is estimated, and the distance between the head 7a of the occupant 7 and the indoor side wall 9 is detected from the size of the roll angle. The detection of the distance between the occupant 7 and the indoor side wall 9 is more accurate. Thus, the curtain airbag 2 can be reliably inflated and deployed between the head 7 a of the occupant 7 and the indoor side wall 9.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a relationship between a roll angle and a roll angular velocity of an automobile.
FIG. 2 is an explanatory diagram showing the relationship between the roll angle and roll angular velocity of the automobile in FIG. 1 and the possibility of rollover of the automobile.
FIG. 3 is a trajectory diagram showing an automobile and an occupant state until the automobile rolls over.
FIG. 4 is a system diagram according to one embodiment of the present invention.
FIG. 5 is a flowchart of FIG. 4;
FIG. 6 is an explanatory diagram showing the relationship between lateral acceleration applied to the automobile and the occupant's head.
7 is an explanatory diagram showing a range of lateral acceleration to be integrated into the automobile in FIG. 6. FIG.
FIG. 8 is an explanatory diagram showing the relationship between the roll angular velocity of the automobile and the behavior of the passenger's head.
FIG. 9 is a diagram showing a movement locus of an occupant head.
FIG. 10 is a system diagram according to another embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Car 2 Curtain airbag 3 Electronic control unit 4 Lateral acceleration sensor 5 Roll angular velocity sensor 7 Crew 7a Crew head 8 Tire 9 Indoor side wall D Distance between interior side wall and occupant head θ Roll angle θ CRIT Critical roll angle ω Roll Angular velocity ωCRIT Critical roll angular velocity ωS Judgment value Mg Center of gravity SSA of the vehicle Static rolling limit S of the vehicle S Threshold line YG Lateral acceleration

Claims (2)

An automobile equipped with an airbag that is folded and stored with the upper end fixed to the upper part of the vehicle body at a position higher than the passenger's head, and that deploys in a curtain shape downward when the automobile rolls over An air bag device for protecting the head of
Immediately before the curtain airbag is deployed, the lateral acceleration applied to the automobile is integrated to estimate the movement locus of the occupant head, and the distance between the occupant head and the indoor side wall is detected from the movement locus, When the curtain airbag is smaller than the width in the vehicle width direction when the curtain airbag is deployed, the airbag apparatus for protecting the head of an automobile is characterized by prohibiting the inflation and deployment of the curtain airbag. An airbag device for protecting a head of an automobile according to claim 1,
An automobile head protecting airbag device , wherein the automobile roll angle is estimated from the automobile roll angular velocity, and the distance between the passenger's head and the interior side wall is detected from the roll angle magnitude .

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