JPH08230610A - Pedestrian protective device - Google Patents

Abstract

PURPOSE: To prevent unnecessary unfolding of an air bag by precisely discriminating collision with a pedestrian. CONSTITUTION: Threshold values of a collision load and a deformation quantity at collision time with a pedestrian are set on the basis of car speed, and a load and a deformation quantity detected by a bumper sensor 21 are respectively compared with the threshold values, and whether or not it is collision with a pedestrian is judged, and when a collision signal from a collision sensor 22 of a front hood tip part is inputted when it is judged as collision with a pedestrian, the collision with a pedestrian is confirmed, and an unfolding signal is sent to a hood air bag device 10, and the hood air bag device 15 is unfolded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pedestrian protection device which is mounted on a front hood of a vehicle such as an automobile and protects a pedestrian who is flipped up by a vehicle collision.

[0002]

2. Description of the Related Art It is known that, for example, when a pedestrian collides in front of a traveling vehicle, the pedestrian is flipped up by the vehicle and then falls on the front hood of the vehicle. At this time, the front hood is equipped with a hood airbag as a means to protect the pedestrian by mitigating the impact when a pedestrian collides with a highly rigid location such as the lower part of the windshield near the windshield or the upper part of the strut tower. It has been proposed to equip pedestrian protection devices.

An example of this pedestrian protection device is disclosed in Japanese Utility Model Laid-Open No. 6-74533. As shown in FIGS. 6 and 7, this pedestrian protection device is provided with a contact detection sensor 37 that detects a contact and emits a signal at the front portion of the automobile 31, such as the front bumper 36, and travels at a vehicle speed equal to or higher than a set value. When the contact detection sensor 37 detects a contact and emits a detection signal, the airbags 34 at the lower part of the windshield 32 and the upper part of the straddle towers on both sides are actuated to operate each air bag. The bag 34 is inflated and deployed on the vehicle body to cushion and protect the pedestrian A that makes a secondary collision on the vehicle body 31.

[0004]

However, in the above-described conventional pedestrian protection device, the contact detection sensor 37 is provided in the front bumper 36 and the like, and when the contact detection sensor 37 detects the contact of any object, the airbag 34 is inflated and deployed. Therefore, it is not possible to determine whether the object is the pedestrian A, a utility pole other than that, or a standing tree,
Even in the case of utility poles and standing trees, there is a problem that the airbag 34 is unnecessarily inflated and deployed.

The present invention has been made in view of the above circumstances, and provides a pedestrian protection device capable of accurately determining a collision of a pedestrian and preventing unnecessary deployment of a hood airbag. Is intended.

[0006]

As a means for solving the above problems, according to the present invention, as shown in FIG. 1, a hood airbag device 10 is attached to a front hood 4, and a hood airbag 15 is attached to the front hood 4. In a pedestrian protection device provided so as to be inflated and deployed upward, a vehicle speed sensor 20 for detecting a vehicle speed, a bumper sensor 21 for detecting a load and a deformation amount by a collision object at a front bumper portion, and a front hood tip portion for collision. A collision sensor 22 that detects a collision of an object, a threshold setting unit C1 that sets a threshold value of a load and a deformation amount corresponding to a pedestrian based on a vehicle speed, and a load and a deformation amount detected by the bumper sensor 21 as the threshold values. Pedestrian collision determining means C2 for comparing and determining whether there is a possibility of collision with the pedestrian, and the collision when there is a possibility of collision with the pedestrian. When a collision signal capacitors 22 is inputted,
The hood airbag device 10 for determining a pedestrian collision
And a deployment instructing means C3 for instructing the deployment of the hood airbag 15.

When the collision of the pedestrian is judged, the expansion instruction means C3 instructs the expansion when a delay time corresponding to the fall delay of the pedestrian elapses after the collision is detected by the bumper sensor 21. be able to.

[0008]

With the above configuration, when any object collides with the front bumper portion, the bumper sensor 21
Then, the collision and the load and the deformation amount by the collision object are detected. Further, in order to determine the collision between the pedestrian and other objects, the threshold value of the load and the deformation amount corresponding to the pedestrian are appropriately set under all traveling conditions based on the vehicle speed. Then, at the time of a collision, the load and the amount of deformation detected by the bumper sensor 21 are compared with those threshold values. For example, when either one of the load and the amount of deformation is smaller than the threshold value, a pedestrian collided instead of an object such as a utility pole. Possibility is reliably determined under all driving conditions.

It is known that when a pedestrian collides, the pedestrian first collides with the front bumper and then collides with the front end portion of the front hood. Therefore, if a collision signal from the collision sensor 22 is input when there is a possibility of a pedestrian collision, it is highly accurately determined that the pedestrian has collided, not a light collision by an object other than the pedestrian. And only when judging the collision of this pedestrian,
A signal for instructing deployment is sent to the hood airbag device 10, and the hood airbag 15 inflates and deploys on the front hood 4. For this reason, a pedestrian who is bounced up by a collision and falls onto the front hood 4 can be used as a hood airbag 15
Received in and protected to mitigate that shock.
In addition, when a utility pole or the like collides or an object other than a pedestrian collides lightly, no signal is sent to the hood airbag device 10, and therefore the hood airbag 15 is prevented from unnecessarily expanding.

When it is determined that a pedestrian has collided with the bumper sensor 21, the bumper sensor 21 detects the collision, and then the expansion instruction is issued when the delay time corresponding to the fall delay of the pedestrian has elapsed. Since the hood airbag 15 is deployed immediately before dropping and colliding, it is possible to ensure protection of the pedestrian by the hood airbag 15.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the pedestrian protection device of the present invention will be described below with reference to FIGS.

Explaining the structure of the front part of the automobile,
For example, as shown in FIG. 2, a front bumper 2 is provided at the forefront part of a vehicle body 1, a front hood 4 is provided at an upper part of an engine room 3 and is inclined downward to the front, and a hood airbag device is provided at this front hood 4. 10 is installed.

In the hood airbag device 10, a rectangular opening 11 is formed in the center of the front part of the front hood 4, and a lid 12 also serving as a hood is attached to the opening 11 so as to be opened and closed. Further, a storage portion 14 is formed by attaching a backup plate 13 to the inside of the hood at the position of the lid 12, and a small-folded hood airbag 15 and a tubular inflator 16 are stored in the storage portion 14 in communication with each other. The inflator 16 ignites the gas generating agent to generate a large amount of gas when an ignition signal as a deployment instruction is input, and introduces this gas into the hood airbag 15. The hood airbag 15 is inflated immediately by the introduction of gas, pushes and opens the lid 12 by the pressure, projects above the front hood 4, and is formed to extend like a mat over substantially the entire area of the front hood 4. There is.

Next, an electronic control system for controlling the operation of the hood airbag device 10 will be described. It has a vehicle speed sensor 20 for detecting the vehicle speed V using a speedometer or the like. In addition, the bumper sensor 21 is attached to the front bumper 2 at the forefront of the vehicle body, and the front body collision, load F of the collision object,
The deformation amount S is detected by utilizing the deformation of the bumper itself due to this collision.

It is known that when a pedestrian collides with the front part of the vehicle body, the pedestrian first collides with the front bumper 2 and then with the tip of the front hood 4.
Therefore, the collision sensor 22 is attached to the tip of the front hood 4.
Are provided to detect collisions of objects. The signals of the vehicle speed sensor 20, the bumper sensor 21, and the collision sensor 22 are input to the control unit 23, and the control unit 23 outputs an ignition signal as a deployment signal to the inflator 16.

The control unit 23 electrically processes the vehicle speed V of the vehicle speed sensor 20, the load F and the deformation amount S of the bumper sensor 21, and the collision signal of the collision sensor 22 to highly accurately determine whether or not a pedestrian has collided. Determine with. Then, it has a function of outputting an ignition signal at a predetermined timing only when it is determined that the collision is with a pedestrian.

Next, the operation of this embodiment configured as described above will be described with reference to the flow chart of FIG. First, the vehicle speed V is calculated (step 1), and this vehicle speed V is compared with the set vehicle speed Vo (step 2). When the vehicle speed V is equal to or lower than the set vehicle speed Vo, the vehicle is substantially stopped, and it is determined that it is safe even if a pedestrian collides, and the routine returns. Further, when the vehicle speed V is equal to or higher than the set vehicle speed Vo, it is determined that the vehicle is traveling, and when the vehicle is traveling, the presence or absence of signals of the load F of the bumper sensor 21 and the deformation amount S is checked (step 3). When there is no sensor signal, it is detected that the vehicle is traveling normally without any object colliding, and the routine similarly returns. As a result, when the vehicle is safe to stop and the vehicle travels normally without any collision, the hood airbag device 10 does not operate because the ignition signal is not output.

When signals of the load F of the bumper sensor 21 and the deformation amount S are input, it is detected that some object has collided, and the timer T is started at the time of this collision (step 4). That is, if a pedestrian collides, a predetermined delay is required until the pedestrian bounces up and falls onto the front hood 4, so the measurement of the ignition timing delay time TDLY corresponding to this drop delay is started. Then, at the time of collision of any object, the deformation amount S due to the collision object is calculated (step 5), and the load F is calculated (step 6).

Here, the collision object of the vehicle will be described. As shown in FIG. 4A, the front bumper 2 of the vehicle body 1
When a pedestrian A collides with the vehicle, and as a tall heavy object similar to a pedestrian, for example, as shown in FIG.
It is possible that the utility pole B collides with the front bumper 2 of the above. Since the electric pole B has high rigidity and is fixed to the ground, the load F due to the impact at the time of collision is large, and at the same time, the deformation amount S of the front bumper 2 is large. On the other hand, since the pedestrian A is also a heavy object, the front bumper 2 is deformed by the impact at the time of a collision and receives the load F, but the pedestrian A has low rigidity and is generally fixed to the ground, so the load F is generally F. And the deformation amount S becomes smaller.

Therefore, if the threshold values Fo and So of the load F and the deformation amount S corresponding to the pedestrian A are set, both the load F and the deformation amount S become larger than the threshold values Fo and So in the case of a collision of the electric pole B. It can be determined that it is a telephone pole B. Further, at the time of collision, one of the deformation amount S and the load F is the threshold value F.
When it is smaller than o and So, it is possible to judge that the possibility of the pedestrian A is clearly distinguished from the case of the electric pole B.

By the way, under the condition that one of the deformation amount S and the load F is smaller than the threshold values Fo and So, the pedestrian A
There is a possibility of either a collision with the object or a light collision with another object. Here, when a pedestrian A collides as shown in FIG. 4A, the pedestrian A is flipped up and collides with the tip portion of the front hood 4. Therefore, by adding the signal from the collision sensor 22 at the front end of the front hood 4, it is possible to appropriately determine whether the collision with the pedestrian A and the light collision by an object other than the pedestrian. Becomes

Therefore, in order to determine the collision object, thresholds Fo and So of the load F and the deformation amount S corresponding to the pedestrian A are set. Further, when the vehicle is traveling, the impact force at the time of collision changes depending on the vehicle speed V. Specifically, the impact force increases as the vehicle speed V increases. Therefore, the threshold values Fo and So are set based on the vehicle speed V. Further, since the time from the collision of the pedestrian A with the front bumper 2 to the collision with the upper surface of the front hood 4 also changes according to the vehicle speed, the ignition timing delay time TDLY corresponding to the fall delay is also set ( Step 7).

In the load F and the deformation amount S detected by the bumper sensor 21, first, the deformation amount S is the vehicle speed V.
Is compared with the threshold value So (step 8), and the deformation amount S
If is larger, the load F is further compared with the threshold value Fo corresponding to the vehicle speed V (step 9). As a result, when both the deformation amount S and the load F are larger than the threshold values Fo and So, the collision with the utility pole B as shown in FIG. To be judged. In this case, the timer T is reset and the process returns (step 12). Therefore, since the ignition signal is not output, the hood airbag device 10 does not operate, which prevents the hood airbag 15 from unnecessarily expanding.

In this collision of the electric pole B, as shown in FIG.
The front bumper 2 is largely deformed as shown in FIG. 2, and then the front portion of the vehicle body 1 is destroyed as shown in FIG. This reduces the impact force of the passenger in the passenger compartment.

On the other hand, if the deformation amount S is smaller than the threshold value So, or if the load F is smaller than the threshold value Fo even if the deformation amount S is larger, it is determined that the pedestrian A may have collided. In this case, the presence or absence of a collision signal from the collision sensor 22 at the tip of the front hood 4 is further checked.
When there is no sensor signal, it is determined that the object other than the pedestrian A is a light collision. in this case,
It is checked whether or not the timer T has reached the ignition timing delay time TDLY corresponding to the fall delay in the case of the pedestrian A (step 11), and this delay time TDLY
If not reached, the process returns to step 10, and when it reaches, the timer T is reset and the process returns (step 1
2). Therefore, the hood airbag device 10 does not operate without outputting the ignition signal, and in this case also, the hood airbag 15 is prevented from unnecessarily expanding.

When the collision signal from the collision sensor 22 is input in the case where the pedestrian A may have collided, the fact that the pedestrian A has actually collided as shown in FIGS. 4 (a) and 4 (b). However, it is definitely judged under all driving conditions.
In this case, it is checked whether the timer T has reached the ignition timing delay time TDLY corresponding to the fall delay of the pedestrian A (step 13), and this delay time T
Ignition signal is output when DLY is reached (step 1
4).

Therefore, when the pedestrian A collides with the front bumper 2 of the vehicle body 1 of the traveling vehicle as shown in FIG. 4 (a), the hood airbag device 10 is activated by the ignition signal only in this case, and the hood air bag device 10 is activated. The bag 15 is shown in FIG.
As shown in (4), the entire front hood 4 is inflated and deployed. Therefore, when the pedestrian A is flipped up by a collision and falls onto the front hood 4 of the vehicle body 1, the pedestrian A can be protected by the hood airbag 15 so as to absorb the impact. .

In this embodiment, when the collision of the pedestrian A is judged, the delay time TD corresponding to the fall delay of the pedestrian A after the collision is detected by the bumper sensor 21.
Since the ignition signal is output as a deployment instruction when LY has passed, the hood airbag 15 does not deploy too early, and the hood airbag 15 is inflated and deployed immediately before the pedestrian A collides with the front hood 4. You can Therefore, the pedestrian A can be reliably protected by the hood airbag 15.

[0029]

As described above, the pedestrian protection device of the present invention has a vehicle speed sensor for detecting a vehicle speed, a bumper sensor for detecting a load and a deformation amount of a collision object at the front bumper portion, and a front hood tip portion. A collision sensor that detects a collision of a collision object, a threshold setting unit that sets a threshold value of a load and a deformation amount corresponding to a pedestrian based on a vehicle speed, and a load and a deformation amount detected by the bumper sensor are compared with the threshold value, respectively. Then, a pedestrian collision determination means for determining whether or not it is a collision with a pedestrian, and when it is determined to be a collision with a pedestrian, by inputting a collision signal of the collision sensor,
Since it is provided with a deployment instruction means for instructing the hood airbag device to deploy the hood airbag after a collision with a pedestrian is confirmed, in all traveling conditions,
A collision with a pedestrian and a collision with an electric pole or another object can be discriminated with high accuracy, and therefore, the hood airbag can be prevented from unnecessarily expanding.

Further, when the collision of the pedestrian is judged, if the expansion instruction is given when the delay time corresponding to the fall delay of the pedestrian has elapsed after the collision detection by the bumper sensor, the pedestrian will fall onto the front hood. Since the hood airbag is deployed immediately before the collision, the pedestrian can be reliably protected by the hood airbag.

[Brief description of drawings]

FIG. 1 is a claim correspondence diagram showing a configuration of a pedestrian protection device of the present invention.

FIG. 2 is a sectional view of a front portion of a vehicle equipped with the pedestrian protection device of the present invention.

FIG. 3 is a flowchart of operation control of a pedestrian protection device.

FIG. 4 is an explanatory diagram showing a collision state of a pedestrian.

FIG. 5 is an explanatory diagram showing a collision state of telephone poles.

FIG. 6 is a perspective view of a vehicle equipped with a conventional pedestrian protection device.

FIG. 7 is an explanatory diagram showing an operating state of a conventional pedestrian protection device.

[Explanation of symbols]

 2 front bumper 4 front hood 10 hood airbag device 15 hood airbag 20 vehicle speed sensor 21 bumper sensor 22 collision sensor 23 control unit C1 threshold setting means C2 pedestrian collision determination means C3 deployment instruction means

Front Page Continuation (72) Inventor Uzuki, 1st Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Co., Ltd. (72) Inventor: Takashi Usui 1, 1 Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Corporation (72) Invention Person Hiroki Ohara Ichin Seiki Co., Ltd., 2-chome, Asahi-cho, Kariya city, Aichi prefecture (72) Inventor Michio Inoue 1 Ochiai, Nagahata, Kasuga-cho, Nishikasugai-gun, Aichi prefecture Toyota Gosei Co., Ltd.

Claims (2)

[Claims] 1. A pedestrian protection device for inflating and deploying an airbag on a front hood of a vehicle at the time of a collision to buffer and protect a pedestrian who makes a secondary collision on the front hood. A vehicle speed sensor for detecting, a bumper sensor disposed on the front bumper portion for detecting a collision load on the front bumper portion, deformed by the collision load and detecting the deformation amount, and disposed on the front end portion of the front hood. A collision sensor that detects the collision of an object with the front end of the front hood, and a threshold setting unit that sets the respective thresholds of the collision load and the deformation amount detected at the time of a collision with a pedestrian based on the vehicle speed, Pedestrian collision that compares the collision load and deformation amount detected by the bumper sensor with the threshold value to determine whether the collision is with a pedestrian When the collision signal from the collision sensor is input when it is determined that the collision with the pedestrian and the collision means, the hood airbag device deploys the hood airbag again by reconfirming the collision with the pedestrian. A pedestrian protection device comprising: a deployment instruction means for instructing 2. The deployment instruction means, when determining the collision with the pedestrian, instructs the deployment when a delay time corresponding to the fall delay of the pedestrian has passed after the collision was detected by the bumper sensor. The pedestrian protection device according to claim 1.