Airbag device for pedestrian protection

Abstract

Provided is an airbag device for pedestrian protection, which can not only achieve rapid inflation and deployment of an airbag cushion, but also suppress damage or the like of the airbag cushion, and which can easily satisfy the need for expanding a pedestrian protection area. A pedestrian protection airbag device (10) is provided with: an airbag cushion (12) that expands and deploys outside a vehicle cabin when a vehicle collision occurs; and a first inflator (14a) and a second inflator (14b), which are activated when a collision occurs in the vehicle, and which supply inflation / deployment gas to the airbag cushion (12), respectively. The first inflator (14a) and the second inflator (14b) are different in starting time when the vehicle collides.

Description

Technical Field

[0001] The present invention relates to a pedestrian protection airbag device for protecting pedestrians struck by a vehicle. Background Art

[0002] For example, the pedestrian protection airbag device described in Patent Document 1 is mounted near the boundary between the engine hood and the windshield of a vehicle. When a collision between the vehicle and a pedestrian is detected, an inflator is activated to supply inflation gas to an airbag cushion, causing the airbag cushion to instantaneously expand and deploy. The inflated and deployed airbag cushion covers the rear side of the engine hood, the lower front part of the windshield, and the lower parts of the left and right A-pillars to protect the head of the pedestrian struck by the vehicle.

[0003] Prior Art Documents

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 2020-100377 Summary of the Invention

[0005] Problems to be Solved by the Invention

[0006] In a pedestrian protection airbag device, the inflated and deployed airbag seat cushion fills the entire vehicle width direction, etc., and the airbag cushion expands and deploys within a relatively wide range. Considering the possible future need to expand the pedestrian protection area, using only one inflator may cause a delay in the expansion and deployment of the airbag cushion, resulting in a delay in the pedestrian protection time point.

[0007] As a method for solving this problem, it is conceivable to use multiple inflators. However, when using multiple inflators, the internal pressure of the airbag cushion will excessively increase in the initial stage of expansion and deployment. As a result, the stitching part of the airbag cushion may rupture. There is also a risk of damage (glass breakage) to the windshield due to the inflated and deployed airbag cushion.

[0008] An object of the present invention is to provide a pedestrian protection airbag device that can achieve rapid expansion and deployment of the airbag cushion, suppress damage to the airbag cushion, etc., and is easily capable of meeting the need to expand the pedestrian protection area.

[0009] Means for Solving the Problems

[0010] A pedestrian protection airbag device according to an embodiment of the present invention includes: an airbag cushion that expands and deploys outside the vehicle body when a vehicle collision occurs; and a plurality of inflators including a first inflator and a second inflator that are activated when a vehicle collision occurs and supply inflation gas for expansion and deployment to the airbag cushion respectively, and have different activation time points when a vehicle collision occurs.

[0011] According to this embodiment, since the activation time points of the first inflator and the second inflator are different, it is possible to suppress a sudden increase in pressure at the initial stage of the inflation and deployment of the airbag cushion. As a result, damage to the airbag cushion can be reduced. In addition, for example, when the inflated and deployed airbag cushion suddenly abuts against a part of the vehicle (such as the windshield), damage to that part (such as glass breakage) can be suppressed. Further, since gas for inflation and deployment is supplied to one airbag cushion by a plurality of inflators, the airbag cushion can be inflated and deployed quickly. Therefore, it is also easier to meet the demand for expanding the pedestrian protection area. Additionally, it is preferable that the performance of the plurality of inflators is the same, but inflators with different performances may also be used. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a plan view showing a state when a pedestrian protection airbag device according to the first embodiment is activated (when inflation and deployment are completed) together with a vehicle.

[0013] Figure 2 is a sectional view showing a state before activation (before inflation and deployment) of the pedestrian protection airbag device according to the first embodiment when cut along line II-II in Figure 1 .

[0014] Figure 3 is a sectional view showing a state when activated (after inflation and deployment are completed) of the pedestrian protection airbag device according to the first embodiment when cut along line II-II in Figure 1 .

[0015] Figure 4 is a state of the airbag cushion according to the first embodiment when laid flat, (a state before inflation and deployment and before folding), (A) a plan view observed from above, and (B) a bottom view (observed from the back).

[0016] Figure 5 is a block diagram showing a control structure of the pedestrian protection airbag device according to the first embodiment.

[0017] Figure 6 is a flowchart showing a control method of the pedestrian protection airbag device according to the first embodiment.

[0018] Figure 7 is a side view showing a state when a pedestrian protection airbag device according to the second embodiment is activated (when inflation and deployment are completed) together with a vehicle.

[0019] Figure 8 is a plan view showing a state when a pedestrian protection airbag device according to the third embodiment is activated (when inflation and deployment are completed) together with a vehicle. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] <Summary of Term Definitions and Embodiment Modes>

[0021] The airbag device for pedestrian protection according to the preferred embodiment of the present invention will be described with reference to the accompanying drawings. In this specification, up and down, left and right, front and back are defined as follows. When an occupant is seated on a vehicle seat in a regular posture, the direction the occupant faces is called the front, and the opposite direction is called the back. When representing coordinate axes, it is called the front-back direction or the vehicle front-back direction. Additionally, when an occupant is seated on a seat in a regular posture, the right side of the occupant is called the right direction, and the left side of the occupant is called the left direction. When representing coordinate axes, it is called the left-right direction or the vehicle width direction. Similarly, when an occupant is seated on a seat in a regular posture, the direction of the occupant's head is called the upper direction, and the direction of the occupant's waist is called the lower direction. When representing coordinate axes, it is called the up-down direction.

[0022] The main protection object of the airbag device for pedestrian protection according to this embodiment is pedestrians. Hereinafter, pedestrians will be taken as an example for description. However, it is not limited thereto. For example, people riding bicycles or motorcycles, as well as people riding skateboards or scooters, etc. are also included in the protection objects.

[0023] The airbag device for pedestrian protection according to this embodiment includes: an airbag cushion that expands and unfolds outside the vehicle compartment when a vehicle collision occurs; and a plurality of inflators, including a first inflator and a second inflator that are activated when a vehicle collision occurs and respectively supply inflation gas for expansion to the airbag cushion.

[0024] "When a vehicle collision occurs" mainly refers to when a vehicle collides with a pedestrian. Whether a vehicle collision occurs and whether it collides with a pedestrian can be determined based on known methods, for example, by detecting through sensors (such as pressure sensors or acceleration sensors) mounted on the vehicle bumper.

[0025] "Outside the vehicle compartment" refers to the outside of the vehicle compartment. For example, the airbag device for pedestrian protection is mounted near the boundary between the engine hood and the windshield of the vehicle, and the airbag cushion expands and unfolds outward in the vehicle width direction from near this boundary. And the inflated and unfolded airbag cushion covers at least the rear side of the engine hood, the lower front end of the windshield, and the lower parts of the left and right A-pillars, protecting the head of the pedestrian hit by the vehicle. The range covering the A-pillar can be set to extend to include the upper middle area above the lower part of the A-pillar, or extend to the entire range of the A-pillar.

[0026] However, in other embodiments, the airbag device for pedestrian protection may be mounted at a position other than near the boundary between the engine hood and the windshield. For example, it may be mounted on the front end side of the engine hood, and the airbag cushion expands and unfolds upward from the gap on the front end side of the engine hood in the entire vehicle width direction. In this case, the inflated airbag cushion covers the front side of the engine hood and / or a part of the rear side thereof to protect the pedestrian hit by the vehicle.

[0027] Hereinafter, an example in which the airbag cushion expands and unfolds near the boundary between the engine hood and the windshield will be described. In addition, the "engine hood" is sometimes also referred to as the "bonnet". In addition, the "windshield" may also be referred to as the "front glass".

[0028] The airbag cushion is generally folded and stored in a housing. The folded airbag cushion may have, for example, a rolled shape, an accordion shape, or a combination thereof. When the vehicle collides, the airbag cushion is inflated by a plurality of inflators supplying gas. The airbag device for pedestrian protection of the present embodiment can suppress a sudden increase in pressure during the initial inflation and deployment of the airbag cushion while maintaining the rapid inflation and deployment of the airbag cushion by staggering the activation time points of the plurality of inflators. The performance of the plurality of inflators is preferably the same, but inflators with different performances may also be used.

[0029] <Embodiment 1>

[0030] As Figure 1 shown, the airbag device 10 for pedestrian protection includes an airbag cushion 12 that expands and unfolds outside the vehicle body when the vehicle collides. The airbag cushion 12 is inflated by the first inflator 14a and the second inflator 14b supplying inflation gas. At this time, the airbag cushion 12 expands and unfolds from the boundary portion 26 between the engine hood 22 and the windshield 24 of the vehicle 20, covering the rear side 22a of the engine hood 22, the lower front portion 24a of the windshield 24, and the lower portions of the left and right A-pillars 28, 28. Although not particularly shown, the range covering the A-pillar may be set to extend to above the upper middle region relative to the lower portion of the A-pillar, or to extend over the entire range of the A-pillar.

[0031] A sensor 32 for detecting a vehicle collision is provided on the front bumper 30 of the vehicle 20. The sensor 32 may be various known sensors, such as an acceleration sensor or a pressure sensor. The sensor 32 is connected to the controller 34, and a signal from the sensor 32 is input to the controller 34. The controller 34 determines whether the vehicle 20 has collided with a pedestrian based on the detection result of the sensor 32. When it is determined that a collision with a pedestrian has occurred, the controller 34 activates the inflators 14a, 14b to expand and deploy the airbag cushion 12.

[0032] As Figure 2As shown, the airbag cushion 12 is normally folded and housed in the housing 16. The housing 16 is, for example, a shallow-bottomed metal case with an open top and extends in the vehicle width direction. The opening of the housing 16 is covered by a cover 18, and the cover 18 is formed with a breakage portion 18a. The breakage portion 18a can be, for example, a perforation, a slit, or a groove. The breakage portion 18a is configured to be torn by the inflating and deploying airbag cushion 12, so that the airbag cushion 12 can easily fly upward from the cover 18.

[0033] Inflators 14a and 14b are fixed to the bottom wall portion 16a of the housing 16. By this fixing, the bottom of the airbag cushion 12 is also fixed to the bottom wall portion 16a of the housing 16. Specifically, first, the inflators 14a and 14b are inserted into the airbag cushion 12, and the studs 41a and 41b of the inflators 14a and 14b project outward from the bottom of the airbag cushion 12. Refer to Figure 4 (B). The studs 41a and 41b project to the lower side of the bottom wall portion 16a and are fastened to the lower surface of the bottom wall portion 16a by nuts. At this time, the bottom of the airbag cushion 12 is pressed against the upper surface of the bottom wall portion 16a by the inflators 14a and 14b. Thereby, the airbag cushion 12 is fixed to the housing 16 together with the inflators 14a and 14b.

[0034] Therefore, in the pedestrian protection airbag device 10, at least the airbag cushion 12, the inflators 14a and 14b, the housing 16, and the cover 18 constitute a modular airbag device. And, by fixing the housing 16 to the vehicle body of the vehicle 20 or fixing it to a bracket or the like mounted on the vehicle body, the pedestrian protection airbag device 10 is mounted on the boundary portion 26 between the engine hood 22 and the windshield 24. In addition, Figure 2 The symbol 29 shown indicates a windshield wiper.

[0035] As Figure 3 shown, when the airbag cushion 12 inflates and deploys, it breaks through the cover 18 and inflates and deploys outside the cover 18. When the airbag cushion 12 is fully inflated and deployed, it has a front inflation portion 51 located on the engine hood 22 and a rear inflation portion 52 located near the lower end portion of the windshield 24 when viewed from the side. The airbag cushion 12 is composed of one chamber, and the front inflation portion 51 and the rear inflation portion 52 communicate with each other. The rear inflation portion 52 extends from the front end of the lower end portion of the windshield 24 to the rear of the lower end portion and straddles the windshield wiper 29.

[0036] Figure 4Shows the state of the airbag cushion 12 when laid flat, that is, the state before inflation deployment and before folding. The airbag cushion 12 is formed into a bag shape by sewing or bonding one or more base fabrics or the like in appropriate positions, or by using the OPW (One-Piece Woven) method. For example, the airbag cushion 12 is formed by sewing the peripheral portions of the front base fabric 12a and the rear base fabric 12b together. Thus, an air chamber (bag) is formed inside between the front base fabric 12a and the rear base fabric 12b, inside the sewing position. When gas is supplied to this air chamber from the inflators 14a, 14b, the air chamber dividing portions of the front base fabric 12a and the rear base fabric 12b expand and deploy.

[0037] Figure 4 (A) The state shown can be understood by comparison with Figure 1 which is also close to the state when observing the airbag cushion 12 after inflation deployment is completed from above. Therefore, when inflation deployment is completed, the airbag cushion 12 can also be regarded as having a central inflation portion 53 located at the center in the vehicle width direction and a pair of side inflation portions 54, 55 located at both ends in the vehicle width direction when observed from above. The central inflation portion 53 and the pair of side inflation portions 54, 55 communicate with each other. The central inflation portion 53 covers the rear end portion of the hood 22 at the center in the vehicle width direction and the vicinity of the lower front end portion of the windshield 24, and the pair of side inflation portions 54, 55 have an upward protruding shape to further cover the lower portions of the A-pillars 28, 28.

[0038] Figure 4 (B) Also shows the regions of the front inflation portion 51 and the rear inflation portion 52 in the side view of the airbag cushion 12. Among them, the area of the front inflation portion 51 is larger than the area of the rear inflation portion 52, but this area ratio can be appropriately changed according to the type of vehicle, etc. For example, in the case of a small vehicle where the impact position of a pedestrian reaches the rear side of the hood on the vehicle, the area of the rear inflation portion 52 can be made larger than the area of the front inflation portion 51.

[0039] Next, refer to Figures 2 to 4 to describe the inflators 14a, 14b.

[0040] The inflators 14a, 14b are configured to be able to supply inflation deployment gas to the airbag cushion 12 respectively. As the inflators 14a, 14b, various inflators filled with a gas generating agent, compressed gas, or both can be used. Here, the inflators 14a, 14b used have the same performance.

[0041] As an example, the inflator 14a has a bottomed cylindrical body filled with a gas generant, and an ignition device is provided at the open end of the cylindrical body. A plurality (two in this case) of studs 41a are provided on the cylindrical body at intervals along the axial direction of the cylindrical body, and are fixed to the housing 16 via the studs 41a. In addition, a plurality of injection holes are formed on the circumferential surface or the bottom surface of the cylindrical body. The gas generant in the gas cylinder is ignited by the ignition device to generate gas, and the gas for expansion deployment is instantaneously supplied into the airbag cushion 12 from the plurality of injection holes.

[0042] The inflators 14a and 14b are housed inside the airbag cushion 12. As Figure 4 shown, they can be inserted into the airbag cushion 12 through the opening 12c of the airbag cushion 12. In this case, the opening 12c is formed in the back base fabric 12b of the airbag cushion 12, for example. Connectors are provided at the ends 42a and 42b of the inflators 14a and 14b to facilitate electrical connection to the controller 34, and the wire harnesses connected to the connectors are arranged to extend outward from the airbag cushion 12 through the opening 12c. In addition, the studs 41a and 41b of the inflators 14a and 14b pass through the through holes formed in the back base fabric 12b and protrude to the outside of the airbag cushion 12.

[0043] As Figure 4 shown, the inflators 14a and 14b are arranged at different positions in the left - right direction, i.e., the vehicle width direction. For example, the inflators 14a and 14b are configured such that they do not overlap completely or partially with each other in the vehicle width direction. Here, the inflators 14a and 14b are arranged on one side and the other side of the center line in the vehicle width direction, and do not overlap with each other at all. Specifically, the inflator 14a is arranged on the left side of the vehicle 20 with respect to the center in the vehicle width direction, and the inflator 14b is arranged on the right side of the vehicle 20 with respect to the center in the vehicle width direction.

[0044] In addition, the inflators 14a and 14b are arranged along the vehicle width direction. This means that the center positions of the inflator 14a and the inflator 14b are located on the same line parallel to the vehicle width direction. Here, the cylindrical axes of the cylindrical inflators 14a and 14b are aligned with the vehicle width direction. In addition, the ignition devices (42a, 42b) of the cylindrical inflators 14a and 14b face each other, and the bottom surfaces of the cylinders (for example, where the injection holes are formed) face the outside in the vehicle width direction.

[0045] In other embodiments, when the inflators 14a and 14b are arranged along the vehicle width direction, the postures or orientations of the inflators 14a and 14b do not have to be parallel to the vehicle width direction. In addition, if the inflators 14a and 14b are not arranged along the vehicle width direction, the positions of the inflators 14a and 14b are different in the vehicle front - rear direction.

[0046] Figure 5Shows a control structure 60 including inflators 14a, 14b of a pedestrian protection airbag device 10. The controller 34 in the pedestrian protection airbag device 10 is an electronic control unit (ECU) including a CPU 71, a memory 72, and an input / output interface 73, and is configured as a microcomputer, for example. The CPU 71 performs required calculations according to a control program and conducts various processes and controls. The memory 72 includes a ROM and a RAM, for example. The ROM stores the control program and control data processed by the CPU 71, and the RAM is mainly used as various working areas for control processing. The input / output interface 73 is electrically connected to the sensors 32 and the inflators 14a, 14b. With this structure, when the controller 34 receives an input signal from the sensors 32 and determines that the vehicle 20 has collided with a pedestrian, a start signal is output to the inflators 14a, 14b.

[0047] The controller 34 can be configured as an airbag ECU capable of communicating with the vehicle-side ECU, and can control not only the operations of the inflators 14a, 14b of the pedestrian protection airbag device 10, but also the operations of the inflators in other airbag devices such as a front airbag device and a side curtain airbag device.

[0048] In other embodiments, the determination of whether the vehicle 20 has collided with a pedestrian can be performed by the vehicle-side ECU, and the controller 34 can receive collision information from the vehicle-side ECU and output a start signal to the inflators 14a, 14b.

[0049] Figure 6 Is a flowchart showing a control method of the pedestrian protection airbag device 10. When it is determined that the vehicle 20 has collided with a pedestrian (vehicle collision: S10), the controller 34 executes this control method.

[0050] In this control method, the start time points of the inflators 14a, 14b are made different. That is, the inflator 14a starts at a first time point, and the inflator 14b starts at a second time point different from the first time point. Here, the controller 34 changes the output time of the start signal so that the second inflator 14b starts later than the first inflator 14a. Specifically, first, a start signal for supplying inflation and deployment gas from the first inflator 14a to the airbag cushion 12 is output (S11), and then, a start signal for supplying inflation and deployment gas from the second inflator 14b to the airbag cushion 12 is output (S12).

[0051] Here, the difference in the activation time points of the inflators 14a and 14b, that is, the ignition delay time, can be, for example, 5 to 20 milliseconds. If it is less than 5 milliseconds, it is almost the same as activating the inflators 14a and 14b simultaneously, and the internal pressure of the airbag cushion 12 may increase excessively in the initial stage of inflation deployment. On the other hand, if it exceeds 20 milliseconds, the increase in the internal pressure of the airbag cushion 12 in the initial stage of inflation deployment may be insufficient. In particular, the inflation deployment of the airbag cushion 12 on one side in the vehicle width direction may be delayed. This may lead to a delay in the pedestrian protection time point and may not be able to protect pedestrians properly.

[0052] By setting it within the range of 5 to 20 milliseconds, a sudden increase in pressure at the initial stage of inflation deployment of the airbag cushion 12 can be suppressed (that is, the peak value of the internal pressure can be reduced). At the same time, the airbag cushion 12 can expand and deploy quickly. In particular, the difference in the inflation deployment amount in the vehicle width direction can be suppressed, and the airbag cushion 12 can be inflated and deployed as a whole, so that pedestrians can be protected properly.

[0053] Within the range of 5 to 20 milliseconds, 10 milliseconds is preferred, or plus or minus 1 millisecond from it. However, it should be noted that this delay time is greatly affected by the type and performance of the inflator used.

[0054] As described above, the airbag device 10 for pedestrian protection according to the present embodiment includes: an airbag cushion 12 that expands and deploys outside the vehicle body when a vehicle collision occurs; and a plurality of inflators including a first inflator 14a and a second inflator 14b. Each inflator is activated when a vehicle collision occurs and supplies inflation gas to the airbag cushion 12, and the activation time points of the first inflator 14a and the second inflator 14b are different when a vehicle collision occurs.

[0055] According to this structure, a sudden increase in pressure at the initial stage of inflation deployment of the airbag cushion 12 can be suppressed, so that damage to the airbag cushion 12 (such as rupture of the stitching part) can be suppressed. Therefore, considering the high output of the plurality of inflators, it is not necessary to additionally reinforce the airbag cushion 12. In addition, when the inflated and deployed airbag cushion 12 suddenly abuts against a part of the vehicle 20 (such as the windshield 24), damage to this part (such as glass breakage) can be suppressed. Therefore, both the rapid inflation deployment of the airbag cushion 12 can be achieved, and the damage to the airbag cushion 12 can be suppressed, and the pedestrian head protection performance can be satisfied, while it is easy to meet the requirement of expanding the pedestrian protection area.

[0056] In the present embodiment, the inflators 14a and 14b have the same performance. Therefore, for example, the structure and control can be simplified.

[0057] In the present embodiment, the inflators 14a and 14b are provided at different positions in the vehicle width direction. Therefore, the difference in the amount of expansion and deployment in the vehicle width direction can be reduced.

[0058] In addition, the inflators 14a and 14b are arranged in the vehicle width direction. Therefore, the difference in the amount of expansion and deployment in the vehicle longitudinal direction is also reduced. In particular, when the ignition devices of the cylindrical inflators 14a and 14b face each other and the bottom surface of the cylinder having the injection holes faces the outside in the vehicle width direction, the expansion and deployment gas can be guided to a pair of side expansion portions 54 and 55 in the airbag cushion 12.

[0059] Next, other embodiments will be described. In addition, centering on the differences from the first embodiment, other embodiments will be described, and for the structures common to the first embodiment, the same or similar reference numerals will be marked and the description will be omitted.

[0060] <Embodiment 2>

[0061] Refer to Figure 7 The pedestrian protection airbag device 10 according to the second embodiment will be described. As Figure 7 shown, the airbag cushion 112 according to the second embodiment may have a sub-chamber 200 that expands and deploys under the hood 22. That is to say, the airbag cushion 112 may be configured to have the structure of the airbag cushion 12 according to the first embodiment as the main chamber 201, and the sub-chamber 200 is connected to the lower side of the main chamber 201.

[0062] In this case, for example, the inflators 14a and 14b ( Figure 7 omitted in the figure) can be inserted into the sub-chamber 200 and fixed to the housing at the position of the boundary portion 26. The gas for expansion and deployment from the inflators 14a and 14b is first supplied to the sub-chamber 200, and then supplied to the main chamber 201 through the communication portion between the sub-chamber 200 and the main chamber 201. The positional relationship between the inflators 14a and 14b in the sub-chamber 200 can be the same as the positional relationship between the inflators 14a and 14b in the first embodiment.

[0063] <Embodiment 3>

[0064] Refer to Figure 8 , as the pedestrian protection airbag device 10 according to the third embodiment, the activation time points of the inflators 140a and 140b when the vehicle 20 has a vulnerable portion 300 will be described. The vulnerable portion 300 refers to, for example, a part of the vehicle structure that is more likely to be deformed or displaced under the influence of the expanding airbag cushion 12 compared to other parts of the vehicle 20.

[0065] In some examples, the vulnerable part 300 moves to the front end or near the front end of the windshield 24 while maintaining its original shape or being deformed from its original shape by contacting the inflated airbag cushion 12 and / or a part of the cover 18 broken by the inflated airbag cushion 12. As an example related to such a vulnerable part 300, it is a part other than the windshield 24. For example, when the wiper link is on one side of the vehicle, it is the wiper or parts related thereto (e.g., wiper panel, wiper shroud, wiper link, etc.).

[0066] When there is such a vulnerable part 300, it is preferable that the inflator farther from the vulnerable part 300 among the inflators 140a and 140b starts first. For example, when the vulnerable part 300 is near the front end of the windshield 24 and on the first side (e.g., the right side) of the vehicle 20 at the center in the vehicle width direction, the inflator 140b on the second side (e.g., the left side) opposite to the first side will start prior to the inflator 140a. Thus, when the inflated airbag cushion 12 itself and / or a part of the broken cover 18 contacts the vulnerable part 300, it is easier to inhibit the breakage of the vulnerable part 300. Therefore, the influence of such breakage on the windshield 24 can be inhibited (e.g., the broken part of the wiper link collides with the windshield 24 and causes the glass to break).

[0067] In some other examples, the vulnerable part 300 can be a part of the windshield 24. The windshield 24 generally has a left - right asymmetric structure, and either the left or right part of the front end of the windshield 24 sometimes protrudes (extends longer) in front of the vehicle body. This part is likely to contact the inflated airbag cushion 12 and / or a part of the cover 18 broken due to inflation, and thus can be a part where the glass is likely to break.

[0068] Even when there is such a vulnerable part 300, it is preferable that the inflator farther from the vulnerable part 300 among the inflators 140a and 140b starts first. Thus, also when the inflated airbag cushion 12 itself and / or a part of the broken cover 18 contacts the vulnerable part 300 (here, when contacting either the protruding left or right part of the front end of the windshield 24), damage to the vulnerable part 300 (such as glass breakage) can be inhibited.

[0069] In addition, it should be noted that the position and influence of the vulnerable part 300 vary greatly depending on the vehicle layout.

[0070] The above - described embodiments are for facilitating the understanding of the present invention and do not limit the present invention. The structures of the embodiments can be combined with each other. In addition, the elements, their configurations, materials, conditions, shapes, sizes, etc. of each embodiment are not limited to the illustrated content and can be appropriately changed.

[0071] For example, the number of inflators only needs to be at least two, and can also be more than three. Preferably, multiple inflators have the same performance, and their activation time points are different when the vehicle collides. For example, three inflators with the same performance can be arranged in the vehicle width direction, and one or both of the inflators on both sides in the vehicle width direction are activated before the inflator in the center in the vehicle width direction. As another example, the performance of multiple inflators can be set to be different. At this time, if the gas generation capacity of the inflator that is activated first is set to be less than that of the inflator that is activated later, the damage to the vehicle body can be reduced more effectively.

[0072] <Additional Considerations for Various Embodiments>

[0073] [Embodiment 1]

[0074] A pedestrian protection airbag device has an airbag cushion that expands and deploys outside the vehicle when the vehicle collides. Among them,

[0075] It has multiple inflators, including a first inflator and a second inflator that are activated when the vehicle collides and respectively supply inflation and deployment gas to the airbag cushion.

[0076] The first inflator and the second inflator have the same performance, and their activation time points are different when the vehicle collides.

[0077] [Embodiment 2]

[0078] For the pedestrian protection airbag device of Embodiment 1, the first inflator and the second inflator have the same performance.

[0079] [Embodiment 3]

[0080] For the pedestrian protection airbag device of Embodiment 1 or 2, the first inflator and the second inflator are arranged at different positions in the vehicle width direction.

[0081] [Embodiment 4]

[0082] For the pedestrian protection airbag device of Embodiment 3, when viewed from the front of the vehicle,

[0083] The first inflator is located on the right side of the vehicle at the center in the vehicle width direction,

[0084] The second inflator is located on the left side of the vehicle at the center in the vehicle width direction.

[0085] [Embodiment 5]

[0086] For the pedestrian protection airbag device according to any one of Embodiments 1 to 4, among them,

[0087] The first inflator and the second inflator are arranged in the vehicle width direction.

[0088] [Embodiment 6]

[0089] The airbag device for pedestrian protection according to any one of Embodiments 1 to 5, wherein

[0090] the airbag cushion is configured to expand and deploy at least in the vehicle width direction from the boundary between the engine hood and the windshield of the vehicle.

[0091] When the vulnerable part is near the lower end of the windshield and is on the first side of the vehicle located at the center in the vehicle width direction when viewed from the front of the vehicle, among the first inflator and the second inflator, the inflator on the second side opposite to the first side starts first.

[0092] [Embodiment 7]

[0093] The airbag device for pedestrian protection according to Embodiment 6, wherein

[0094] the vulnerable part is a part of the vehicle structure that is liable to be deformed or displaced under the influence of the expanding airbag cushion.

[0095] [Embodiment 8]

[0096] The airbag device for pedestrian protection according to any one of Embodiments 1 to 5, wherein

[0097] the airbag cushion is configured to expand and deploy from the boundary between the engine hood and the windshield of the vehicle.

[0098] [Embodiment 9]

[0099] The airbag device for pedestrian protection according to any one of Embodiments 1 to 8, wherein

[0100] when the vehicle collides, the difference in the activation time points of the first inflator and the second inflator is 5 to 20 milliseconds.

[0101] [Embodiment 10]

[0102] The airbag device for pedestrian protection according to any one of Embodiments 1 to 9, wherein

[0103] it further includes a controller connected to the first inflator and the second inflator.

[0104] When the vehicle collides, the controller

[0105] outputs an activation signal to the first inflator to activate the first inflator at a first time point; and

[0106] Output a start signal to the second inflator, causing the second inflator to start at a second time point different from the first time point.

[0107] [Embodiment 11]

[0108] A control method for a pedestrian protection airbag device, the pedestrian protection airbag device including: an airbag cushion that expands and deploys outside the vehicle body when a vehicle collision occurs; a first inflator and a second inflator having the same performance; and a controller connected to the first inflator and the second inflator, wherein

[0109] When a vehicle collision occurs, the controller executes

[0110] Output a start signal for the first inflator to supply inflation and deployment gas to the airbag cushion, and

[0111] Output a start signal for the second inflator to supply inflation and deployment gas to the airbag cushion, and cause the second inflator to start later than the first inflator.

[0112] [Embodiment 12]

[0113] The control method for a pedestrian protection airbag device according to Embodiment 11, wherein

[0114] The second inflator starts 5 to 20 milliseconds later than the first inflator.

[0115] [Embodiment 13]

[0116] The control method for a pedestrian protection airbag device according to Embodiment 11 or 12, wherein

[0117] The airbag cushion is configured to expand and deploy at least in the vehicle width direction from the boundary between the engine hood and the windshield of the vehicle,

[0118] The first inflator and the second inflator are arranged in the vehicle width direction.

[0119] Symbol Explanation

[0120] 10…Airbag device for pedestrian protection, 12…Airbag cushion, 12a…Surface base fabric, 12b…Back base fabric, 12c…Opening, 14a…First inflator, 14b…Second inflator, 16…Housing, 16a…Bottom wall portion, 18…Cover, 18a…Fracture portion, 20…Vehicle, 22…Engine hood, 22a…Rear side, 24…Windshield, 24a…Lower front end, 26…Boundary portion, 28…A-pillar, 29…Windshield wiper, 30…Front bumper, 32…Sensor, 34…Controller, 41a, 41b…Stud, 51…Front expansion portion, 52…Rear expansion portion, 53…Central expansion portion, 54, 55…Side expansion portions, 60…Control structure, 71…CPU, 72…Memory, 73…Input / output interface, 112…Airbag cushion, 140a, 140b…Inflator, 200…Sub-chamber, 201…Main chamber, 300…Vulnerable portion.

Claims

1. An airbag device for pedestrian protection, having an airbag cushion that expands and deploys outside the vehicle body when a vehicle collision occurs, wherein, it includes a first inflator and a second inflator that are activated when a vehicle collision occurs and supply inflation and deployment gas to the airbag cushion respectively, the activation time points of the first inflator and the second inflator are different when a vehicle collision occurs.

2. The airbag device for pedestrian protection according to claim 1, wherein, the first inflator and the second inflator have the same performance.

3. The airbag device for pedestrian protection according to claim 1, wherein, the first inflator and the second inflator are arranged at different positions in the vehicle width direction.

4. The airbag device for pedestrian protection according to claim 3, wherein, when viewed from the front of the vehicle, the first inflator is located on the right side of the vehicle at the center in the vehicle width direction, the second inflator is located on the left side of the vehicle at the center in the vehicle width direction.

5. The airbag device for pedestrian protection according to claim 1, wherein, the first inflator and the second inflator are arranged along the vehicle width direction.

6. The airbag device for pedestrian protection according to claim 1, wherein, the airbag cushion is configured to expand and deploy at least between the boundary portion between the engine hood and the windshield of the vehicle in the vehicle width direction, when the vulnerable part is near the front end of the windshield and, when viewed from the front of the vehicle, on the first side of the vehicle at the center in the vehicle width direction, among the first inflator and the second inflator, the inflator on the second side opposite to the first side starts first.

7. The airbag device for pedestrian protection according to claim 6, wherein, the vulnerable part is a part of the vehicle structure that is liable to be deformed or displaced under the influence of the expanding airbag cushion.

8. The airbag device for pedestrian protection according to any one of claims 1 to 5, wherein, the airbag cushion is configured to expand and deploy from the boundary portion between the engine hood and the windshield of the vehicle.

9. The airbag device for pedestrian protection according to any one of claims 1 to 7, wherein, when a vehicle collision occurs, the difference in the activation time points of the first inflator and the second inflator is 5 to 20 milliseconds.

10. The airbag device for pedestrian protection according to any one of claims 1 to 7, wherein, it further has a controller connected to the first inflator and the second inflator, and when a vehicle collision occurs, the controller outputs an activation signal to the first inflator to cause the first inflator to start at a first time point; and, outputs an activation signal to the second inflator to cause the second inflator to start at a second time point different from the first time point.

11. A control method for a pedestrian protection airbag device, the pedestrian protection airbag device comprising: An airbag cushion that expands and deploys outside the vehicle body when a vehicle collision occurs; A first inflator and a second inflator having the same performance; And a controller connected to the first inflator and the second inflator, wherein when a vehicle collision occurs, the controller executes outputting an activation signal for causing the first inflator to supply inflation and deployment gas to the airbag cushion, and Output a start signal to cause the second inflator to supply inflation gas to the airbag cushion and cause the second inflator to start later than the first inflator.

12. The control method of the pedestrian protection airbag device according to claim 11, wherein The second inflator starts only 5 to 20 milliseconds later than the first inflator.

13. The control method of the pedestrian protection airbag device according to claim 11 or 12, wherein The airbag cushion is configured to expand at least in the vehicle width direction from the boundary between the engine hood and the windshield of the vehicle. The first inflator and the second inflator are arranged in the vehicle width direction.

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