JPH08276816A - Hood air bag device - Google Patents

Abstract

PURPOSE: To prevent the defective damping caused by the shortage of inner pressure during running at a high speed and the shortage of impact absorption force during running at a low speed by providing an inner pressure adjusting means for increasing the inner pressure when an air bag is expanded with the increase in car speed. CONSTITUTION: An inner pressure adjusting device 17 is provided in a bulge 16 to adjust the expansion volume of an air bag 15, and the inner pressure adjusting device 17 is provided with a belt winding roller 19 and a fastening belt 22. The running speed of a vehicle 11, which is detected by a car speed sensor 26 and the rotation quantity of the belt winding roller 19, which is detected by a roller rotation sensor 21 are inputted to a control device 27 to determine the rotation quantity of a drive motor in either normal or reverse direction. That is, while the vehicle 11 is running at a low speed, the drive motor is normally rotated through the gear of the belt winding roller 19 and the roller rotation sensor 21 for loosening the fastening belt 22 wound around the belt winding roller 19. Therefore, the inner pressure is lowered. While the vehicle is running at a high speed, the drive motor is reversely rotated, making the fastening belt 22 limit the expansion of the air bag 15, increasing the inner pressure of the air bag 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, when a running vehicle collides with a pedestrian, deploys an airbag on the hood of the vehicle and absorbs the impact of the secondary collision with the hood. The present invention relates to a hood airbag device that is relaxed to protect pedestrians.

[0002]

2. Description of the Related Art It is known that when a running vehicle collides with a pedestrian, the collided pedestrian is secondarily collided with the lower half of the body by the front portion of the vehicle body and the upper surface of the hood at the front portion of the vehicle body. . Therefore, for example, Japanese Utility Model Laid-Open No. 6-74533 discloses a pedestrian protection airbag device in which an airbag is deployed on a hood or the like at the front of a vehicle and the airbag absorbs the impact of the secondary collision. It has been described and will be described with reference to FIGS. 12 and 13.

This pedestrian protection airbag system includes a windshield 2 near the lower portion, which is a highly rigid portion of the front upper surface of the vehicle body of the vehicle 1, and left and right fenders 3, 3 above the straddle tower. Airbag 4 in 3 places
An airbag module including the inflator 5 and the inflator 5 is housed.

When the contact detection sensor 7 provided on the front bumper 6 at the front part of the vehicle body detects the contact with the pedestrian H and outputs a detection signal, the signal is received and the 3
Each of the airbags 4 accommodated in the respective places is inflated and deployed to reduce the impact caused by the secondary collision between the pedestrian H and the highly rigid portion on the front surface of the vehicle body.

[0005]

However, in the above-described conventional pedestrian protection airbag device, the pedestrian H which is collided with the vehicle 1 by the airbag 4 deployed on the upper surface of the front portion of the vehicle body such as the hood 8 or the like. However, the impact of the secondary collision with the hood 8 is absorbed and relaxed.

However, the speed of the pedestrian at the time of the second collision with the airbag is not constant, and normally changes with the change of the speed of the vehicle. Therefore, assuming that the impact of a pedestrian's secondary collision with the hood is high, if the internal pressure of the airbag is set to a high value, the same effect will be obtained even if an appropriate cushioning effect is obtained during high-speed running. In the case of a collision during low-speed running with the setting, there is a disadvantage that an appropriate cushioning effect cannot be obtained.

On the contrary, if the internal pressure of the airbag is set low so that an appropriate cushioning effect can be obtained at low speed running,
When a collision occurs during high-speed traveling, the internal pressure is insufficient, causing a phenomenon of bottoming, and again, there is a disadvantage that an appropriate cushioning effect cannot be obtained.

The present invention has been made in view of the above circumstances, and provides a hood airbag apparatus having a mechanism for adjusting the internal pressure of an airbag deployed on a hood to an optimum pressure according to a vehicle speed. It is an object.

[0009]

As means for solving the above problems, the hood airbag apparatus of the present invention sends an ignition signal to an inflator when a collision between a running vehicle and a pedestrian is detected, In the hood airbag device that deploys the airbag on the hood by the gas generated by the inflator and absorbs and absorbs the impact when the pedestrian makes a secondary collision with the hood, the airbag is deployed. The internal pressure adjusting means for increasing the internal pressure of the vehicle is provided as the vehicle speed increases.

Further, the internal pressure adjusting means may be a deployment capacity increasing / decreasing mechanism for increasing or decreasing the deployment capacity of the airbag according to the vehicle speed. In addition, the expansion capacity increasing and decreasing mechanism,
The tightening belt can change its length according to the vehicle speed, and can be brought into contact with the surface of the expanding airbag to change the expanding capacity of the airbag. Further, the expansion capacity increasing / decreasing mechanism may be a moving core that moves in position according to the vehicle speed to change the expansion capacity of the airbag.

[0011]

With the above-described structure, while the vehicle is traveling, the internal pressure of the airbag when deployed by the internal pressure adjusting means in accordance with the vehicle speed operates such that the higher the vehicle speed, the higher the internal pressure of the airbag. When a collision is detected and the airbag is deployed, the airbag is always deployed with an optimum internal pressure according to the vehicle speed at that time.

Further, if the internal pressure adjusting means is a mechanism for increasing / decreasing the expansion capacity of the air bag, it is possible to adjust linearly to changes in vehicle speed.

Further, if the tightening belt that changes the length according to the vehicle speed and abuts against the surface of the airbag to be deployed to change the deployment capacity of the airbag is used as the deployment capacity increasing / decreasing mechanism, the air at the time of deployment can be improved. The internal pressure of the bag can be adjusted steplessly according to the vehicle speed.

Further, even if a moving core whose position is moved according to the vehicle speed to change the deployment capacity of the airbag is used as the deployment capacity increasing / decreasing mechanism, the internal pressure of the airbag during deployment is continuously variable according to the vehicle speed. Can be adjusted to

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of a hood airbag device according to the present invention will be described below with reference to FIGS.

1 to 7 show an embodiment of the hood airbag device of the present invention. A vehicle 11 equipped with the hood airbag device has a front bumper 12 provided at the front end of the vehicle body. A pedestrian collision detection sensor 13 is embedded on the entire side in the vehicle width direction. The pedestrian collision detection sensor 13 is a touch sensor whose contacts are made conductive when compressed by a collision load input from the front, and is capable of detecting a collision with a pedestrian when the vehicle is traveling.

A bulge 16 is formed near the front of the hood 14 at the front of the vehicle body so as to project rearward from the hood 14 and serve as an inflation port for the airbag 15.
Inside the bulge 16, an internal pressure adjusting device 17 that adjusts the deployment capacity of the airbag 15 is installed.

As shown in FIG. 2, the internal pressure adjusting device 17 includes a frame 18 having a U-shaped cross-section which is open in the front-rear direction of the vehicle body and the upper side thereof, and the rear side of the frame 18 (right side in the figure).
The belt winding roller 19 whose both ends are rotatably supported by the rising walls 18a on both sides, and one end of which is fixed to the rear side of the bottom plate 18b of the frame 18, and the other end of which can be wound by the belt winding roller 19. An attached tightening belt 22 is provided. In addition, on the outside of the rising wall 18a on one side (front side in FIG. 2),
A gear 19 axially attached to the shaft of a belt winding roller 19 that extends through the rising wall 18a to the outside.
a and a roller rotation sensor 21 that detects the amount of rotation of the belt winding roller 19 are provided. Further, an airbag module 25, which is an assembly of the folded airbag 15 and the inflator 23 integrally attached to the case 24, is attached to an opening formed in the bottom plate 18b of the frame 18.

More specifically, a gear (worm wheel) 19a of the belt winding roller 19 and a roller rotation sensor (worm wheel) 21 mesh with a worm gear 20a formed on the rotary shaft of the drive motor 20. The roller rotation sensor 21 has a large number of teeth so that the rotation amount when the length of the tightening belt 22 is adjusted from the longest to the shortest is less than one rotation (for example, 3/4 rotation). .

The control of the drive motor 20 is performed by the traveling speed data of the vehicle 11 input from the vehicle speed sensor 26 and the belt winding roller 19 input from the roller rotation sensor 21 as shown in the block diagram of FIG. When the rotation amount data (rotation angle data of the roller rotation sensor 21) is input to the control device 27, either the normal or the reverse is selected depending on the vehicle speed at that time and the belt winding state of the belt winding roller 19 at that time. The amount of rotation in one direction is determined, and control is performed so that the determined amount of rotation is driven.

That is, when the vehicle 11 is traveling at a low speed, the drive motor 20 is controlled to rotate forward,
The tightening belt 22 wound around the belt winding roller 19 is unwound, and the tightening belt 22 is lengthened and loosened. Therefore, when the airbag 15 is inflated in this state, as shown in FIG. 4, the airbag 15 is inflated to the maximum capacity, so that the gas generation amount of the inflator 23 is constant and the internal pressure thereof is relatively low.

When the vehicle 11 is traveling at a high speed, the drive motor 20 is controlled so as to rotate in the reverse direction, the tightening belt 22 is wound around the belt winding roller 19, and the tightening belt 22 becomes short and becomes tense. Therefore, when the airbag 15 is deployed in this state, as shown in FIG. 5, the tightening belt 22 is in tension, so that the airbag 15 is inflated by the tightening belt 22 in the portion of the bulge 16 on the proximal end side. Since the capacity is reduced by the limited amount and the gas generation amount of the inflator 23 is constant, the internal pressure thereof is increased.

Next, the operation of this embodiment configured as described above will be described with reference to the flowchart of FIG.

While the vehicle 11 is traveling, the bulge 16
The length of the tightening belt 22 of the internal pressure adjusting device 17 installed therein expands and contracts according to the vehicle speed, and the deployment capacity of the airbag 15 is constantly adjusted.

That is, when the control program starts, in step 1, the vehicle speed Vx input from the vehicle speed sensor 26 and the rotation angle θx input from the roller rotation sensor 21 are respectively taken in, and then calculated in step 2 in advance. Refer to the table showing the relationship between the vehicle speed and the optimum deployment capacity of the airbag, and the vehicle speed Vx at that time
The optimum rotation angle θs is determined.

Then, the process proceeds to step 3, and it is judged whether or not the present rotation angle θx fetched in step 1 and the rotation angle θs for obtaining the optimum expansion capacity at that speed are substantially equal to each other, and they are almost equal. In this state, airbag 1
If 5 is deployed, it is determined that it can be deployed to the optimal deployment capacity, that is, the airbag internal pressure that is optimal for buffering a pedestrian who has collided, and the process proceeds to step 4, and after stopping the drive motor 20, To prepare for the next data input.

Further, in step 3, when the current rotation angle θx and the rotation angle θs for achieving the optimum expansion capacity at that speed are out of the substantially equal range, the process proceeds to step 5. , It is determined whether the current rotation angle θx is larger than the optimum rotation angle θs. If the current rotation angle θx is larger, the process proceeds to step 6, the drive motor 20 is rotated in the forward direction, and tightened. After rewinding and loosening the belt 22, the process returns to step 1 and the above steps are repeated until the current rotation angle θx becomes substantially equal to the optimum rotation angle θs.

If the current rotation angle θx is smaller than the optimum rotation angle θs in step 5, the process proceeds to step 7 in which the drive motor 20 is rotated in the reverse direction and the tightening belt 22 is wound up to tighten the tension. , And returns to step 1, and the above steps are repeated until the current rotation angle θx becomes substantially equal to the optimum rotation angle θs.

In this way, the internal pressure adjusting device 17 operates in accordance with the traveling speed of the vehicle 11 and is constantly adjusted so that the deployment capacity optimal for the vehicle speed Vx at that time, that is, the airbag 15 has the optimal internal pressure. .

Therefore, when the running vehicle 11 collides with a pedestrian, the pedestrian collision detection sensor 13 detects the collision and outputs an ignition signal to the inflator 23, and the gas generated in the ignited inflator 21 causes the air bag module. The airbag 15 of 25 inflates and deploys on the hood 14 from the bulge 16.

At this time, in the internal pressure adjusting device 17 installed in the bulge 16, the length of the tightening belt 22 is adjusted according to the vehicle speed. Adjusting tightening belt 2
Since the expansion of the bulge 16 on the proximal end side is limited and the expansion capacity thereof is reduced by 2, the internal pressure of the airbag is inflated to a relatively high level, and the impact at the time of a secondary collision at a high speed is insufficient. Protects pedestrians with optimal damping without bottoming out. If you are running at low speed,
The tightening belt 22 is loosened, the deployment capacity of the airbag 15 is maximized, the airbag internal pressure is inflated to a relatively low level, and the impact at the time of a secondary collision is sufficiently absorbed to protect the pedestrian. In this way, the internal pressure of the airbag is constantly adjusted to be in an optimum state so that the shock absorbing performance according to the vehicle speed can be obtained.

8 to 11 show other embodiments of the present invention in which a moving core is used as the expansion capacity increasing / decreasing mechanism, and the same components as those in the above embodiment are designated by the same reference numerals. The detailed description will be omitted, and the following description will be given with reference to the drawings.

The hood airbag device shown in FIG. 8 is provided with an airbag module 25 and a moving core 31 as a deployment capacity increasing / decreasing mechanism in a bulge 16 formed near the front of the hood 14.

The movable core 31 is attached to the upper end of an arm 32 which is swingably provided with a lower end 33 as a fulcrum.
The arm 32 is oscillated by an amount corresponding to the vehicle speed by a drive mechanism (not shown), and the movable core 31 enters the expansion region of the airbag 35 in the bulge 16 to expand the airbag 35. Is configured to be reduced depending on the vehicle speed, and the same operational effect as that of the above-described embodiment can be obtained.

Further, the hood airbag device shown in FIG. 9 is provided with an airbag module 25 and a movable core 41 as a deployment capacity increasing / decreasing mechanism in a bulge 16 formed in the front of the hood 14.

The moving core 41 is slidably provided in the bulge 16 by engaging with a rail 42 laid in the front-rear direction of the vehicle body. The moving core 41 is driven by a drive mechanism (not shown) to move inside the bulge 16. 1 to FIG. 1 are configured so that the deployment capacity of the airbag 45 is reduced according to the vehicle speed by the moving core 41 entering the airbag 45 deployment area by an amount corresponding to the vehicle speed. It is possible to obtain substantially the same operational effects as the embodiment shown in FIG.

Further, the hood airbag device shown in FIG. 10 is provided with an airbag module 25 and a moving core 51 as a deployment capacity increasing / decreasing mechanism in a bulge 16 formed in the front of the hood 14.

The moving core 51 is provided so as to be able to move up and down by a pantograph mechanism 52 provided in the bulge 16. The moving core 51 is raised by a drive mechanism (not shown) by an amount according to the vehicle speed, and the moving core 51 is provided in the bulge 16. Airbag 55
The deployment capacity of the airbag 55 is configured to be reduced according to the vehicle speed by the moving core 51 entering the deployment area of the vehicle, and is substantially the same as the embodiment shown in FIGS. 1 to 7. The effect is obtained.

Further, the hood airbag apparatus shown in FIG. 11 is provided with an airbag module 25 and a moving core 61 as a deployment capacity increasing / decreasing mechanism in a bulge 16 formed in the front of the hood 14.

The moving core 51 is vertically movable by a rack-and-pinion mechanism 62 provided in the bulge 16, and is raised by a drive mechanism (not shown) by an amount corresponding to the vehicle speed, so that the bulge 16 is moved. The movable core 51 enters the position for compressing the auxiliary bag 65a for internal pressure adjustment, which is formed to communicate with the inside airbag 65 in the opposite direction (front side of the vehicle body) to adjust the internal pressure according to the vehicle speed. The auxiliary bag 65a is configured so that the expansion capacity is reduced by the compressed capacity, and the same effects as those of the embodiment shown in FIGS. 1 to 7 are obtained.

In each of the above-mentioned embodiments, the case where the method of increasing or decreasing the deployment capacity of the airbag is adopted as the internal pressure adjusting means of the airbag has been described, but other internal pressure adjusting means is used as a pedestrian at low speed running. At the time of collision with, the same effect can be obtained by not filling the airbag with a part of the gas generated by the inflator so as to reduce the internal pressure.

[0042]

As described above, the hood airbag device according to the present invention is provided with the internal pressure adjusting means for increasing the internal pressure when the airbag is deployed as the vehicle speed increases, so that the airbag for high speed traveling can be provided. It prevents deficiency of cushioning such as bottoming due to insufficient internal pressure and insufficient shock absorbing power due to excessive internal pressure of the airbag while traveling at a relatively low speed, and is adjusted to the optimal airbag internal pressure according to the vehicle speed. Can be reliably protected.

Further, by using an air bag deployment capacity increasing / decreasing mechanism as the internal pressure adjusting means, the air bag internal pressure can be linearly controlled according to the vehicle speed. Further, as a deployment capacity increasing / decreasing mechanism, if a tightening belt that changes its length according to the vehicle speed and contacts the surface of the airbag to be deployed to change the deployment capacity of the airbag is used, it accurately follows changes in vehicle speed. Can be controlled. Furthermore, if a moving core is used as the expansion capacity increasing / decreasing mechanism, this mechanism can have a simple structure.

[Brief description of drawings]

FIG. 1 is a cross-sectional side view showing a state in which a hood airbag device according to an embodiment of the present invention is mounted on a vehicle.

FIG. 2 is a partially cutaway perspective view of an internal pressure adjusting device in an airbag deployed state.

FIG. 3 is a plan view showing a deployed state of the airbag during low-speed traveling.

FIG. 4 is a sectional view taken along line IV-IV of FIG. 3;

FIG. 5 is a view showing a deployed state of the airbag during high-speed traveling.
FIG.

FIG. 6 is a block diagram showing control of a deployment capacity adjusting mechanism.

FIG. 7 is a flowchart showing a control program.

FIG. 8 is an explanatory view showing the outline of another embodiment of the present invention.

FIG. 9 is an explanatory view showing the outline of another embodiment of the present invention.

FIG. 10 is an explanatory view showing the outline of still another embodiment of the present invention.

FIG. 11 is an explanatory view showing the outline of another embodiment of the present invention.

FIG. 12 is a perspective view of a vehicle equipped with a conventional pedestrian protection airbag device.

FIG. 13 is an explanatory diagram showing an operating state of the airbag device.

[Explanation of symbols]

 11 Vehicle 14 Hood 15 Airbag 16 Bulge 17 Inner Pressure Adjustment Device 19 Belt Winding Roller 20 Drive Motor 21 Roller Rotation Sensor 22 Tightening Belt 25 Airbag Module 26 Vehicle Speed Sensor 27 Control Device 31 Moving Core 32 Arm 35 Airbag 65a Auxiliary for Internal Pressure Adjustment bag

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yoshito Hori 1st Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Co., Ltd. (72) Inventor Toshiaki Matsumoto 1st Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Co., Ltd. ( 72) Inventor Hiroki Ohara, Ichijin Seiki Co., Ltd., 2-chome, Asahi-cho, Kariya City, Aichi Prefecture (72) Inventor Michio Inoue 1 Nagachihata, Ochiai, Kasuga-cho, Nishikasugai-gun, Aichi Toyoda Gosei

Claims (4)

[Claims] 1. When a collision between a running vehicle and a pedestrian is detected, an ignition signal is sent to an inflator, gas generated by the inflator deploys an airbag on a hood, and the airbag causes the walking. In a hood airbag device that absorbs and relaxes a shock when a person makes a secondary collision with the hood, the hood is provided with an internal pressure adjusting means for increasing the internal pressure when the airbag is deployed as the vehicle speed increases. Airbag device. 2. The hood airbag apparatus according to claim 1, wherein the internal pressure adjusting means is a deployment capacity increasing / decreasing mechanism that increases or decreases the deployment capacity of the airbag according to a vehicle speed. 3. The expansion capacity increasing / decreasing mechanism is a tightening belt that changes its length in accordance with the vehicle speed and contacts the surface of the expanding airbag to change the expanding capacity of the airbag. Item 4. The hood airbag device according to Item 2. 4. The hood airbag apparatus according to claim 2, wherein the expansion capacity increasing / decreasing mechanism is a moving core whose position changes according to a vehicle speed to change the expansion capacity of the airbag.