JP7691838B2 - Airbag device - Google Patents

Description

The present invention relates to an airbag device having an airbag that deploys from the front of a vehicle such as an automobile to the outside of the vehicle.

As a technology relating to an airbag device that is deployed on the outside of a vehicle such as an automobile, for example, Patent Document 1 describes how the front portion of the front airbag is deployed to protect the pedestrian when a collision with a pedestrian is predicted, and how only the left and right corner bag portions are deployed to reduce damage from contact when the vehicle is parked.
Patent Document 2 describes a system in which an airbag positioned on the front side of the vehicle body is deployed to prevent pedestrians and others who are thrown up from falling and colliding with the road surface and suffering injuries to the head and face, and a pedestrian behavior control unit formed on the front edge moves the pedestrian to the side of the vehicle, preventing them from being thrown up onto the hood.
Patent Document 3 describes a method for predicting the weight of a specific pedestrian from an image captured by an imaging device, and setting the airbag deployment conditions to provide optimal spring force, damping force, and deployment timing for a pedestrian airbag.

Furthermore, as a technology for determining the type of collision when a collision occurs, for example, Patent Document 4 describes a method for determining the type of collision, such as a full-wrap collision, an offset collision, an oblique collision, etc., based on the output of a first and a second acceleration sensor arranged on one and the other side of the vehicle width direction.
Furthermore, as a technique for controlling the deployment mode of airbags, for example, Patent Document 5 describes a technique for deploying a plurality of adjacently arranged airbags in a predetermined order so that they overlap each other.

JP 2006-88893 A JP 2006-219119 A JP 2007-296941 A JP 2019-162983 A Special table 2017-516702 publication

2. Description of the Related Art Generally, vehicles such as automobiles are designed so that, in the event of a frontal collision, the front structure of the vehicle body is crushed to absorb the collision energy.
Even when an airbag is deployed outside the vehicle, the load received by the airbag is usually transferred to the vehicle body structural members, and any collision energy that cannot be absorbed by the airbag is absorbed by the collapse of the vehicle body structure.
Such energy absorption is often assumed to occur when the vehicle colliding with the vehicle has a weight equivalent to that of the host vehicle and the collision occurs at a relative speed of, for example, several tens of kilometers per hour.
However, in reality, there is a possibility of a collision with a vehicle larger than the vehicle itself, a collision with a vehicle traveling faster than the assumed vehicle speed, or a multiple collision in which multiple vehicles collide in succession, and it is also possible that sufficient energy absorption will not be possible due to the collapse of the vehicle body structure alone.
For this reason, there is a demand for reducing damage during a collision without relying excessively on the vehicle body structure.
In view of the above-mentioned problems, an object of the present invention is to provide an airbag device capable of reducing damage caused by a collision with an object.

In order to solve the above-mentioned problems, the airbag device of the present invention is an airbag device including: a first airbag that deploys forward from a center in a vehicle width direction at a front part of a vehicle body; a second airbag that deploys forward from both left and right sides of the first airbag at the front part of the vehicle body; a pre-crash determination unit that establishes a pre-crash determination when the possibility of a collision with an object is equal to or higher than a predetermined value; and an airbag deployment control unit that deploys at least one of the first airbag and the second airbag in response to the establishment of the pre-crash determination, and the airbag device is configured to predict a collision mode with the object. The airbag deployment control unit, when the predicted collision type is a specific offset collision in which the relative velocity vector of the object with respect to the vehicle has a predetermined or greater component in a direction approaching the center of the vehicle in the vehicle width direction , deploys the first airbag and then deploys the second airbag so as to press against and abut against a side portion of the first airbag, and executes a slope portion formation control in which the surface portions of the first airbag and the second airbag form a slope portion in which the rear side of the vehicle protrudes outward in the vehicle width direction relative to the front side of the vehicle.
In the specification and claims, an offset collision includes an oblique offset collision (also called an oblique collision) in which an object collides with the vehicle from a direction inclined relative to the longitudinal direction of the vehicle.
According to this, the input from the object to the first and second airbags is transmitted to the vehicle body via the sloped portion, generating a yaw moment that causes the vehicle to begin turning in the opposite direction to the side that experienced the offset collision.
As a result, the vehicle turns away from the collision side with the object, and part of the collision energy input from the object is converted into kinetic energy, reducing the amount of energy absorbed by the vehicle body structure due to crushing, etc., and reducing collision damage to the vehicle.

In the present invention, the airbag deployment control unit may be configured to execute the slope portion formation control when an overlap ratio predicted at the time of a collision with the object is equal to or greater than a predetermined threshold value.
In addition, in the present invention, the airbag deployment control unit can be configured to execute the slope portion formation control when the relative velocity vector of the object with respect to the vehicle has a predetermined or greater component in a direction approaching the center of the vehicle in the vehicle width direction.
According to each of these inventions, by performing the slope portion formation control for the collision types in which the effect of reducing collision damage by the slope portion formation control is large, damage in these collision types can be effectively reduced, while not interfering with the deployment control of the airbag suitable for the other collision types.

In the present invention, the airbag deployment control unit can be configured to not deploy the first airbag when the predicted collision type is a full-wrap collision, and to deploy the left and right second airbags in abutting or adjacent state in the center of the vehicle width direction.
According to this, an object colliding from the front side of the vehicle can be stably received by the left and right second airbags, and the collision energy can be effectively absorbed by the second airbags.

As described above, the present invention provides an airbag device that can reduce damage during a collision with an object.

1 is a diagram showing a schematic configuration of an embodiment of an airbag device to which the present invention is applied; 1 is a block diagram showing a schematic configuration of a system for controlling an airbag device according to an embodiment; 5 is a flowchart illustrating an operation of the airbag device of the embodiment during a collision. 1 is a diagram showing a schematic diagram of a state after a vehicle having an airbag device according to an embodiment has undergone a full-wrap collision with another vehicle; 1 is a diagram illustrating a state in which a vehicle having an airbag device according to an embodiment is about to collide with another vehicle in an oblique offset manner; 10A and 10B are diagrams illustrating a state after a vehicle having the airbag device of the embodiment has collided with another vehicle in an oblique offset manner and a slope portion formation control has been performed;

Hereinafter, an embodiment of an airbag device to which the present invention is applied will be described.
The airbag device of the embodiment is provided in the front part of a vehicle body of an automobile such as a passenger car, for example, and aims to reduce damage when the automobile collides with an object such as another vehicle.
FIG. 1 is a diagram showing a schematic configuration of an airbag device according to an embodiment.
FIG. 1 shows a vehicle having an airbag device according to an embodiment as viewed from above.
The vehicle 1 has, for example, a so-called two-box vehicle shape having an engine compartment 20 that protrudes forward from a passenger compartment 10 .

The vehicle interior 10 is a portion having a space in which passengers and the like are accommodated.
The engine compartment 20 is a portion having a space in which power train components such as an engine, a transmission, and in the case of an electric vehicle, a motor generator and its control devices are housed.
The engine compartment 20 is provided with a front side frame 21, a bumper beam 22, a front bumper 23, etc.

The front side frame 21 is a structural member that protrudes forward from a toe board (not shown), which is a partition wall provided at the front end of the passenger compartment 10 .
The front side frame 21 functions as a base to which, for example, a power train, a cross member to which a front suspension is attached, and a strut housing that accommodates struts of a MacPherson strut type front suspension are attached.
The front side frame 21 is formed by assembling and welding members formed by press-molding steel plates, for example, so that its cross-sectional shape when viewed from the vehicle longitudinal direction is a rectangular closed cross-section.

The bumper beam 22 is a structural member provided at the front of the vehicle body and extending in the vehicle width direction.
The bumper beam 22 is formed into a beam shape with a closed cross section by, for example, assembling and welding members formed by press-molding steel plates, or by using an extruded aluminum alloy material.
The bumper beam 22 has a middle portion connected to the front end portions of the left and right front side frames 21 .
Both ends of the bumper beam 22 in the vehicle width direction protrude outward in the vehicle width direction relative to the front side frames 21 .
The bumper beam 22 is a load transmission member that transmits the load received by the central airbag 30C, the right airbag 30R, and the left airbag 30L (described later) from an object in a collision to the rear side of the vehicle body via the front side frames 21.

The front bumper 23 is an exterior member provided at the front end of the vehicle body, and is configured by attaching a bumper face constituting a skin portion, which is formed from, for example, a PP-based resin, to the vehicle body by brackets or the like (not shown).
The front portion of the front bumper 23 is curved so that the front side of the vehicle is convex when the vehicle 1 is viewed from above.
When the vehicle 1 is viewed from above, the bumper beam 22 is formed in an arc shape that is convex toward the front of the vehicle so as to follow the curvature of the front portion of the front bumper 23 .

The airbag device of this embodiment includes a center airbag 30C, a right airbag 30R, and a left airbag 30L.
Each airbag is formed into a bag shape by joining panels made of a base fabric such as nylon 66 fabric, and is deployed by blowing in deployment gas generated by an inflator 111 depending on whether a pre-crash determination is made.
The central airbag 30C is provided in the center of the vehicle body in the vehicle width direction.
The center airbag 30C functions as the first airbag of the present invention.
The right airbag 30R is provided adjacent to the central airbag 30C on the right side in the vehicle width direction.
The left airbag 30L is provided adjacent to the central airbag 30C on the left side in the vehicle width direction.
The right airbag 30R and the left airbag 30L function as a second airbag of the present invention.
In FIG. 1, the right airbag 30R and the left airbag 30L are shown deployed, while the central airbag 30C is shown in an undeployed state.

The central airbag 30C, the right airbag 30R, and the left airbag 30L are normally (before the pre-crash determination is established) attached to the bumper beam 22 in a folded state and are housed inside the front bumper 23.
In the event of a collision, each airbag breaks a weakened portion formed in the front bumper 23 and is projected forward of the vehicle, and deploys forward in front of the front bumper 23 .

When only the right airbag 30R and the left airbag 30L are deployed, the inner ends of the airbags in the vehicle width direction abut against or are adjacent to each other at the center in the vehicle width direction.
In this state, the central airbag 30C is disposed rearward of the right airbag 30R and the left airbag 30L, facing the areas where the right airbag 30R and the left airbag 30L abut or are adjacent to each other with a gap therebetween in the front-rear direction.

FIG. 2 is a block diagram showing a schematic configuration of a system for controlling the airbag device according to the embodiment.
The system for controlling the airbag device includes an airbag control unit 110, an environment recognition unit 120, and the like.
Each of these units can be configured as a microcomputer having, for example, an information processing unit (processor) such as a CPU, a storage unit such as a RAM or a ROM, an input/output interface, and a bus connecting these.
In addition, each unit is connected directly or via an in-vehicle LAN such as a CAN communication system, so that they can communicate with each other.

The airbag control unit 110 issues commands to an inflator 111 and a vent control valve 112, controlling them to inflate the right airbag 30R, the central airbag 30C, and the left airbag 30L, and controls the state of their deployment.
The airbag control unit 110 functions as an airbag deployment control unit of the present invention.
The inflator 111 is a chemical (pyrotechnic) gas generating device that generates gas for inflating each airbag in response to a command from the airbag control unit 110 .
The inflators 111 are provided independently for the right airbag 30R, the central airbag 30C, and the left airbag 30L, respectively, and are capable of individually controlling whether or not the right airbag 30R, the central airbag 30C, and the left airbag 30L are deployed, and the timing at which the deployment begins.

The vent control valves 112 are provided in the right airbag 30R, the central airbag 30C, and the left airbag 30L, respectively, and serve to open and close vent flow paths (not shown) that exhaust gas from within each airbag (for example, to the atmosphere).
The vent control valve 112 has a function of independently opening and closing the vent flow paths of the right airbag 30R, the central airbag 30C, and the left airbag 30L in response to a command from the airbag control unit 110, for example.
The vent control valve 112 may include, for example, an electromagnetic valve.

The airbag control unit 110 is provided with a pressure sensor 113 .
The pressure sensor 113 has a function of detecting the internal pressure of each of the right airbag 30R, the central airbag 30C, and the left airbag 30L.
The airbag control unit 110 can detect the load input state to each airbag based on the output of the pressure sensor 113 .

The environment recognition unit 120 recognizes the environment around the vehicle based on the outputs of various sensors.
The environment recognition unit 120 has a function of recognizing, for example, various objects such as other vehicles, pedestrians, buildings, trees, and terrain around the vehicle 1 (host vehicle), as well as road shapes (lane shapes), etc.
The environment recognition unit 120 functions as a pre-crash determination section that establishes a pre-crash determination when a collision with an object such as another vehicle is unavoidable (when the possibility of a collision is equal to or greater than a predetermined level).
The environment recognition unit 120 is connected to a stereo camera device 121, a millimeter wave radar device 122, a laser scanner device 123, etc.

The stereo camera device 121 has a pair of cameras arranged at a predetermined distance (baseline length) apart, and has the function of recognizing objects such as other vehicles, pedestrians, and cyclists, as well as detecting the relative position of the objects with respect to the vehicle 1 using well-known stereo image processing.
The stereo camera device 121 has a function of recognizing attributes of an object by pattern recognition of a captured image, etc. For example, when the object is another vehicle, the stereo camera device 121 has a function of recognizing the size of the other vehicle (whether it is a large vehicle that is significantly heavier than the vehicle 1, such as a truck, a bus, or a large SUV).

The millimeter wave radar device 122 is a radar device that uses radio waves in a frequency band of, for example, 30 to 300 GHz, and has the function of detecting the presence or absence of an object and the relative position of the object with respect to the vehicle 1.
The laser scanner device (LIDAR) 123 has the function of scanning the area around the vehicle 1, for example by emitting pulsed near-infrared laser light, and detecting the presence or absence of an object, the relative position of the object to the vehicle 1, the shape of the object, etc., based on the presence or absence of reflected light and the time difference until the reflected light returns.
The environmental recognition unit 120 is capable of recognizing the type of collision with the object (e.g., the object's velocity vector relative to vehicle 1, the collision position relative to vehicle 1, etc.) and the attributes of the object (e.g., in the case of a vehicle, the type, shape, size, etc.) when a collision with an object such as another vehicle is unavoidable (when a pre-crash judgment is made).
The environment recognition unit 120 has a function as a collision type prediction section.

Next, the operation of the airbag device of the embodiment will be described.
FIG. 3 is a flow chart illustrating the operation of the airbag device of the embodiment during a collision.
Each step will be explained in order below.

<Step S11 : Pre-crash determination result determination>
The environment recognition unit 120 uses a known pre-crash judgment logic to estimate the possibility of a collision with another vehicle (an example of an object as referred to in the present invention) approaching from the front of the vehicle 1, and determines whether the estimated possibility is equal to or exceeds a preset threshold value.
If the possibility of a collision occurring is equal to or greater than the threshold, it is determined that a collision is unavoidable, a pre-crash determination is established, and the process proceeds to step S12 , otherwise the series of processes is ended (returned).

<Step S12 : Collision Type Recognition>
The airbag control unit 110 recognizes the predicted mode of a collision of the other vehicle with the vehicle 1 .
The collision type can be recognized based on information from the environment recognition unit 120, for example.
For example, the collision position of the other vehicle with respect to the vehicle 1 (the range of the vehicle 1 that will be hit by the other vehicle) and the velocity vector of the other vehicle with respect to the vehicle 1 immediately before the collision are recognized based on the results of monitoring the relative position of the other vehicle with respect to the vehicle 1 before and after the collision by the stereo camera device 121, the millimeter wave radar device 122, and the laser scanner device 123. This velocity vector includes information regarding the relative speed of the other vehicle with respect to the vehicle 1 and the collision direction (angle).
Then, proceed to step S13 .

<Step S13 : Offset collision determination>
The airbag control unit 110 determines whether the collision type recognized in step S12 is a specific offset collision (including an oblique offset collision) in which the collision damage can be mitigated by the slope portion formation control described later.
For example, if the overlap ratio is equal to or greater than a predetermined value, or if the relative velocity vector of the other vehicle V with respect to the vehicle 1 has a velocity component in the inward direction of the vehicle 1 in the vehicle width direction (in the direction approaching the center of the vehicle 1 in the vehicle width direction) that is equal to or greater than a predetermined value, it can be determined that a specific offset collision has occurred.
If it is determined that it is a specific offset collision, the process proceeds to step S14 , otherwise the process proceeds to step S15 .

<Step S14 : Slope portion formation control>
The airbag control unit 110 executes slope portion formation control to form a slope portion that is inclined in the fore-and-aft direction of the vehicle body 1 so that the surface of the airbag group consisting of the right airbag 30R, one of the left airbags 30L, and the central airbag 30C gradually protrudes outward in the vehicle width direction from the front to the rear of the vehicle 1.
The specific contents of the slope portion formation control will be explained in detail later.
Then, the series of processes ends.

<Step S15 : Deploying left and right airbags>
The airbag control unit 110 deploys the right airbag 30R and the left airbag 30L.
At this time, the central airbag 30 is maintained in an undeployed state.
In addition, the vent control valve 112 opens the vent flow paths of the right airbag 30R and the left airbag 30L.
Then, the series of processes ends.

The state, function and effect of the airbag device of the embodiment in each of the above-mentioned airbag control modes will be described below.
FIG. 4 is a schematic diagram showing a state after a vehicle having the airbag device of the embodiment has undergone a full-wrap collision with another vehicle.
When the pre-crash determination is established and the predicted collision type is a full-overlap collision, as shown in FIG. 1, the right airbag 30R and the left airbag 30L are deployed, and the central airbag 30C is left undeployed.
Additionally, the vent passages of the right airbag 30R and the left airbag 30L are opened.
As shown in FIG. 4, another vehicle V collides with the front portions of the right airbag 30R and the left airbag 30L.
At this time, the right airbag 30R and the left airbag 30L contract while discharging gas therein through the vent passages, thereby absorbing the collision energy.

Next, the specific contents of the slope portion formation control will be described.
FIG. 5 is a schematic diagram showing a state immediately before a vehicle having the airbag device of the embodiment collides with another vehicle in an oblique offset manner.
When the pre-crash determination is established and the predicted collision type is a specific offset collision, the airbag control unit 110 first deploys only the center airbag 30C as shown in FIG.
The central airbag 30C passes between the undeployed right airbag 30R and left airbag 30L and deploys and inflates toward the front side of the vehicle.

After a predetermined time interval has elapsed since the central airbag 30C was deployed, the airbag control unit 110 deploys the right airbag 30R and the left airbag 30L.
FIG. 6 is a schematic diagram showing a state after a vehicle having the airbag device of the embodiment has collided with another vehicle in an oblique offset manner and the slope portion formation control has been performed.
The inner portions of the right airbag 30R and the left airbag 30L in the vehicle width direction come into contact with and press against the side portions of the central airbag 30C, thereby sinking into the interior of the central airbag 30 while depressing the side portions of the central airbag 30C.
The central airbag 30 is pressed by the right airbag 30R and the left airbag 30L at a middle portion in the front-rear direction and is depressed, so that the internal pressure increases.
As a result, the front portion of the central airbag 30C inflates so as to wrap around the front portions of the right airbag 30R and the left airbag 30L.
At this time, the side portions at the front of the central airbag 30C, and the front portions and outer side portions in the vehicle width direction of the right side airbag 30R and the left side airbag 30L form a slope portion S that is inclined in the fore-and-aft direction of the vehicle 1 so as to gradually protrude outward in the vehicle width direction from the front side to the rear side of the vehicle 1.

When a load F is input to the slope S due to a collision with another vehicle V, a yaw moment is generated that turns the vehicle 1 to the side opposite the collision side (to the right side in the case where the collision occurs from the left side of the vehicle 1 as shown in FIG. 7) due to the inclination of the slope S. This yaw moment causes the vehicle 1 to start turning to the right as shown by the dashed arrow.
At this time, the other vehicle V starts turning to the left as shown by the dashed arrow, and transitions from the state shown by the solid line to the state shown by the dashed line.
Thereafter, the vehicle 1 and the other vehicle V move forward side by side with their front bodies in contact with each other. For example, in the example shown in FIG. 6, the vehicles move toward the upper side in FIG.

As described above, according to this embodiment, the following effects can be obtained.
(1) By performing slope formation control prior to the occurrence of an offset collision, the input load F from the other vehicle V to each airbag is transmitted to the vehicle body via the slope portion S, generating a yaw moment that causes the vehicle 1 to begin turning in the direction opposite to the side that experienced the offset collision.
As a result, vehicle 1 turns to the opposite side of the collision while accompanying other vehicle V (close to the vehicle), converting part of the collision energy input from the other vehicle V into kinetic energy, thereby reducing the amount of energy absorbed by the body structure, etc., and mitigating the collision damage to vehicle 1.
(2) By performing the slope portion formation control when the overlap ratio predicted at the time of a collision with another vehicle V is equal to or greater than a predetermined threshold value, or when the relative velocity vector of the other vehicle V with respect to the vehicle 1 has a component in a direction approaching the center in the vehicle width direction of the vehicle 1, it is possible to effectively suppress collision damage in a collision type in which the effect of reducing collision damage by the slope portion formation control is large. Moreover, in other collision types, the control of airbag deployment, etc., appropriate for the collision type is not prevented from being performed.
(3) In the event of a full-overlap collision, etc., the right airbag 30R and the left airbag 30L are deployed in a state of abutting or adjacent to each other in the center of the vehicle width direction, so that the right airbag 30R and the left airbag 30L can stably receive another vehicle V colliding from the front side of the vehicle 1, and the right airbag 30R and the left airbag 30L can effectively absorb the collision energy.

(Modification)
The present invention is not limited to the above-described embodiment, and various modifications and variations are possible, which are also within the technical scope of the present invention.
(1) The configurations of the airbag device and the vehicle are not limited to the above-described embodiment and may be modified as appropriate.
For example, the structure, shape, material, manufacturing method, arrangement, and number of each member and part that constitutes these, as well as the specific contents of various controls, are not limited to the embodiments and can be changed as appropriate.
(2) The method of performing the pre-crash determination and the method of determining the type of collision are not limited to the methods described in the above embodiment and may be modified as appropriate.
(3) The method for forming the inclined surface portion in the embodiment is merely an example and can be modified as appropriate.
For example, the shape, positional relationship, number of airbags, etc. of the airbag group constituting the slope portion can be changed as appropriate.

REFERENCE SIGNS LIST 1 vehicle 10 vehicle interior 20 engine compartment 21 front side frame 22 bumper beam 23 front bumper 30R right side airbag 30C center airbag 30L left side airbag 110 airbag control unit 111 inflator 112 vent control valve 113 pressure sensor 120 environment recognition unit 121 stereo camera device 122 millimeter wave radar device 123 laser scanner device V other vehicle S slope portion

Claims (3)

a first airbag that deploys forward from a center portion in a vehicle width direction at a front portion of a vehicle body of the vehicle;
a second airbag that deploys forward from both left and right sides of the first airbag in the front portion of the vehicle body;
a pre-crash determination unit that establishes a pre-crash determination when the possibility of a collision with an object is equal to or higher than a predetermined value;
an airbag deployment control unit that deploys at least one of the first airbag and the second airbag in response to the establishment of the pre-crash determination,
a collision type prediction unit for predicting a collision type with the object,
the airbag deployment control unit, when the predicted collision type is a specific offset collision in which the relative velocity vector of the object with respect to the vehicle has a predetermined or greater component in a direction approaching the center of the vehicle in the vehicle width direction , deploys the first airbag, and then deploys the second airbag so as to press against and abut against a side portion of the first airbag, and executes a slope portion formation control in which surface portions of the first airbag and the second airbag form a slope portion in which the rear side of the vehicle protrudes outward in the vehicle width direction relative to the front side of the vehicle. 2. The airbag device according to claim 1, wherein the airbag deployment control unit, when a predicted collision type is a full -wrap collision, does not deploy the first airbag, and deploys the left and right second airbags in abutting or adjacent state in a center portion in a vehicle width direction. The specific offset collision is an oblique collision.
3. The airbag device according to claim 1 or 2,

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