JP2023177572A - air bag device - Google Patents

Abstract

To provide an air bag device that reduces a load to be added to a front window screen from an inflated and deployed airbag cushion and is free from restriction in an installation position of straightening cloth.SOLUTION: An air bag device includes: a folded airbag cushion 11; an inflator 12 for jetting an inflation gas for inflating the airbag cushion 11; a first flap for covering at least an open side of the airbag cushion 11 at the time of being inflated and deployed and cleaved when being pressed by the inflated and deployed airbag cushion 11; and a second flap 30 provided on an outside or inside of the first flap to limit a projection amount of the inflated and deployed airbag cushion 11 to a front window screen 8. The second flap 30 includes a fracture part that fractures when being pressed by the inflated and deployed airbag cushion 11. The fracture part includes an initial fracture part 32 to be a part providing a starting point where the second flap 30 fractures from the fracture part.SELECTED DRAWING: Figure 1B

Description

The present invention relates to an airbag device and the like that restrains an occupant seated in a passenger seat or a driver seat from the front.

In recent years, electric vehicles have become more popular. In electric vehicles, there is no longer an engine located at the front of the vehicle, and as shown in FIGS. 11(a) and 11(b), there is a tendency for the instrument panel 7 to become smaller. Contact portion 102 indicates a portion where airbag cushion 101 first contacts front window screen 8 during inflation and deployment. As the instrument panel 7 becomes smaller, the distance D from the top surface of the instrument panel 7 to the contact portion 102 becomes shorter.

Therefore, in the airbag device 100, the airbag cushion 101 comes into contact with the front window screen 8 immediately after being inflated and deployed, and the front window screen 8 may be damaged by the impact caused by the load applied from the airbag cushion 101.

Conventionally, Patent Document 1 discloses a configuration in which a tether is stretched inside the airbag cushion 101 as a response to the above problem. The tether stretched within the airbag cushion 101 connects the attachment opening of the inflator and the inner surface of the contact portion 102, and has means for extending its length in stages. .

Japanese Patent Application Publication No. 2014-133485

Generally, an airbag cushion of an airbag device is often provided with a rectifying cloth inside. The straightening cloth is a member that adjusts the flow of gas injected from the inflator, and by providing the straightening cloth at an optimal position, the behavior of the airbag cushion when it is inflated and deployed can be stabilized.

However, in the configuration of the airbag device of Patent Document 1, there is a high possibility that the tether provided inside the airbag cushion imposes restrictions on the installation position of the rectifying cloth.

The present invention has been made in view of the above circumstances, and provides an airbag device that reduces the load applied to the front window screen from the inflated and deployed airbag cushion, and does not impose restrictions on the installation position of the rectifying cloth. The purpose is to realize the following.

In order to solve the above-mentioned problems, the airbag device of the present invention includes a folded airbag cushion, an inflator that injects inflation gas to inflate the airbag cushion, and at least an open side of the airbag cushion when the airbag cushion is inflated and deployed. A first flap that covers the airbag and ruptures when pressed by the airbag cushion during inflation and deployment; and a first flap provided on the outside or inside of the first flap to limit the amount of protrusion of the airbag cushion toward the front window screen during inflation and deployment. a second flap, the second flap has a breaking part that breaks when pressed by the airbag cushion being inflated and deployed, and the breaking part is a part that provides a starting point for the second flap to break at the breaking part. It has an initial rupture part.

In the present invention, the fracture portion may be formed by an opening.

In the present invention, the initial breakage portion may be provided in a region including the center of the breakage portion.

In the present invention, the opening of the initial fracture portion may be formed by a cut, a pinhole, or a slit having a predetermined width.

In the present invention, the shape of the opening in the initial fracture portion may be a circle, an ellipse, or a polygon.

In the present invention, the initial fracture portion may have a configuration in which a corner portion of a polygonal opening is continuous with the fracture portion.

In the present invention, the breaking portion of the second flap may be configured to break near the timing when the airbag cushion that is inflated and deployed comes into contact with the front window screen.

In the present invention, the second flap has a band-shaped portion and a widened portion whose width increases in a direction intersecting the longitudinal direction of the band-shaped portion, and the breaking portion is provided in the widened portion. It's okay.

In the present invention, the widened portion may include a region that overlaps with an outer surface portion of a contact portion where the airbag cushion and the front window screen come into contact with each other during inflation and deployment.

In the present invention, the broken part has a second broken part and a third broken part on both sides of the initial broken part, and the second broken part and the third broken part include both ends in the extending direction of the widened part or the vicinity thereof. A configuration extending to the area may also be adopted.

In the present invention, the opening in the initial fracture part is a cut or a slit having a required width, and the interval between the cuts or slits is longer than the interval between the cuts in the second fracture part and the third fracture part. You may.

In the present invention, the second flap has a region that overlaps with the outer surface of the contact portion where the airbag cushion and the front window screen come into contact during inflation and deployment, and a pair of connecting portions for fixing the second flap to the vehicle side. You may adopt the configuration provided.

In the present invention, the first flap may have a fragile portion that ruptures when pressed by the airbag cushion being inflated and deployed, and the second flap may be ruptured after the fragile portion is ruptured. .

In the present invention, the first flap may be provided so as to wrap around the airbag cushion in the stored state.

The present invention may include a storage case that stores the airbag cushion in a stored state and is attached to the storage section of the instrument panel, and the first flap and the second flap may be fixed to the storage case. good.

In the present invention, the second flap may be made of a woven fabric, and the direction in which the warp or weft of the woven fabric is provided is substantially parallel to the breaking direction of the broken portion.

In the present invention, a configuration may be adopted in which the distance between adjacent apertures at the initial breakage portion of the second flap is wider than the distance between adjacent apertures at the breakage portion other than the initial breakage portion.

In the present invention, the broken portion of the second flap may have a structure in which the number of fabrics stacked is smaller than the number of fabrics stacked in the area other than the broken portion.

The present invention includes a first flap that covers at least the open side of the airbag cushion when it is inflated and deployed in the stored state, and that ruptures when pressed by the airbag cushion that is being inflated and deployed; and a second flap that limits the amount of protrusion of the airbag cushion toward the front window screen during inflation and deployment. The second flap has a breakage portion that breaks when pressed by the airbag cushion during inflation and deployment, and the breakage portion includes an initial breakage portion that provides a starting point for the second flap to break at the breakage portion. . When inflation gas is injected from the inflator, the airbag cushion starts to inflate and deploy, and first the first flap ruptures. Thereafter, the amount of protrusion of the airbag cushion toward the front window screen is limited by the second flap until the second flap expands and breaks at the breakage portion. This reduces the impact that the inflated and deployed airbag cushion gives to the front window screen, compared to an airbag device that does not have a second flap.

In the present invention, both the first flap and the second flap are provided outside the airbag cushion. The second flap may include, for example, a region that overlaps the outer surface of the contact portion where the airbag cushion and the front window screen come into contact during inflation and deployment, and a pair of connection portions for fixing the second flap to the vehicle side. A different configuration can be adopted. The configuration of the present invention does not impose any restrictions on the installation position of the rectifying cloth provided inside the airbag cushion. According to the present invention, it is possible to arrange the rectifying cloth at an optimal position and reduce the load applied to the front window screen from the inflated and deployed airbag cushion.

FIG. 1A is a schematic configuration diagram of the airbag device according to the embodiment as seen from the side when it is attached to a vehicle. FIG. 1B is a diagram illustrating the airbag cushion of FIG. 1A just before it inflates and deploys and contacts the front window screen. FIG. 2(a) is a perspective view of the airbag device according to the embodiment, as seen from an angle, with the first flap wrapped around the outside of the folded airbag cushion. FIG. 3 is a perspective view of a state in which a second flap is attached to the outside of the first flap, viewed from an angle. FIG. 3A is a perspective view of the airbag cushion around which the first flap of FIG. 2(a) is wrapped, and the airbag cushion with the first flap torn, viewed from an angle. FIG. 3B is an exploded view of the airbag cushion of FIG. 2(a) and a developed view of the first flap. FIGS. 3C(a) to 3C(c) are diagrams showing the process of wrapping the first flap around the airbag cushion. FIG. 4(a) is a view of the second flap in FIG. 2(b) laid flat and viewed from above, and FIG. 4(b) is a view showing another example of the second flap. FIG. 5A(a) is a diagram illustrating the progress of fracture of the fractured portion of the second flap in the airbag device according to the embodiment, and FIG. 5A(b) is an enlarged view of the fractured portion. FIG. 5B(a) is a diagram illustrating a state in which the second flap ruptures in an airbag device according to a modified example of the embodiment (initial rupture part is a wide slit), and FIG. 5B(b) , is an enlarged view of the fractured part. FIG. 5C is a diagram illustrating a situation in which the second flap ruptures in an airbag device according to a modification of the embodiment (the initial rupture part is a pinhole). FIG. 5D is a diagram illustrating a situation in which the second flap ruptures in an airbag device according to a modified example of the embodiment (the initial rupture portion is square). FIG. 5E is a diagram showing a situation in which the second flap ruptures in an airbag device according to a modification of the embodiment (the initial rupture part is triangular). FIG. 5F is a diagram illustrating a situation in which the second flap ruptures in an airbag device according to a modified example of the embodiment (the initial rupture portion is circular). FIG. 5G is a diagram illustrating a situation in which the second flap ruptures in an airbag device according to a modified example of the embodiment (the initial rupture portion is oval). FIG. 5H is a diagram illustrating a situation in which the second flap ruptures in an airbag device according to a modification of the embodiment (in which the initial rupture part is a cut similar to the second rupture part and the third rupture part). FIG. 6(a) is an enlarged view of the storage section in FIG. 1A, and FIG. 6(b) is a view showing the state immediately after the airbag cushion starts to inflate and deploy. 7(a) shows the initial restriction stage by the second flap, FIG. 7(b) shows the first breaking stage by the second flap, FIG. 7(c) shows the second breaking stage by the second flap, and FIG. d) shows the separation stage when the second flap is completely ruptured; FIG. 8 is a perspective view showing a modification of the storage case. FIG. 9 is a side view of the storage case of FIG. 8 attached to the storage section of the instrument panel. 10(a) is a plan view, FIG. 10(b) ) is a sectional view taken along line AA. FIG. 10(a) is a side view of a state in which the airbag cushion of a conventional airbag device in a gasoline car has been fully inflated, and FIG. 10(b) is a side view of a conventional airbag cushion in an electric vehicle. FIG. 3 is a side view of the airbag cushion of the device in a state where inflation and deployment are completed.

Embodiments of the present invention will be described in detail below with reference to the drawings. Note that the following embodiments are examples of the present invention, and are not intended to limit the scope of the present invention, its applications, or its uses.

This embodiment is an airbag device 10 for protecting an occupant 5 seated on a seat 1 of a vehicle such as an automobile. The airbag device 10 shown in FIG. 1A is provided for a passenger seat. The airbag device 10 is arranged in the instrument panel 7 of a vehicle, and when an impact is applied to the vehicle such as during a collision, the airbag cushion 11 inflates and deploys toward the occupant 5 to protect the occupant's head, chest, and abdomen. etc. from the front.

In the present invention, the term "occupant" refers to, for example, a dummy for frontal collision test (Hybrid III AM50/NHTSA [National Highway Traffic Safety Administration] standard [49CFR Part572 Subpart E and O]). A person with a physique equivalent to an average male in the United States, based on the human body dummy for frontal crash tests determined by the United States, and has approximate dimensions of 175 cm in height, 88 cm in sitting height, and 78 kg in weight. However, the present invention is also applicable to other human dummies.

In this specification, "above" and "upper side" mean the direction of the head of the occupant 5 seated in the regular position of the seat 1, and "bottom" and "lower side" mean the direction of the foot of the occupant 5. There is. Here, the "regular position" refers to the center position of the seat cushion 2 in the seat 1 in the left-right direction, and the position where the back of the occupant 5 contacts the backrest 3 vertically. Further, "front" and "front side" may refer to the front direction of the occupant 5 seated in the normal position of the seat 1, and "rear" and "rear side" may refer to the rear direction of the occupant 5.

The seat 1 includes a seat cushion 2 and a backrest 3, as shown in FIG. 1A. A headrest 4 is attached to the upper end of the backrest portion 3 via a rod-shaped support member 6. The seat 1 may have a backrest 3 and a headrest 4 integrally formed.

As shown in FIG. 1A, the airbag device 10 is arranged inside a storage section 7a provided in a passenger seat panel of the instrument panel 7. The passenger seat panel is a panel placed in front of the passenger seat. The airbag cushion 11 is stored in the storage section 7a in a folded and stored state by folding or winding. A storage case 13 for the airbag device 10 is attached to the storage section 7a.

In a non-inflated state before the airbag cushion 11 is inflated and deployed, the opening of the storage section 7a is closed by a door section 7b provided on the instrument panel 7. A front window screen 8 is located on an extension line in the normal direction of the opening surface of the storage section 7a. The front window screen 8 is a plate provided on the front window of the vehicle, and is provided so as to be inclined toward the vehicle interior with respect to the upper surface of the instrument panel 7.

FIG. 1B shows a state immediately before the airbag cushion 11 of the airbag device 10 is inflated and deployed and comes into contact with the front window screen 8. FIG. The contact portion 11a indicates a portion where the airbag cushion 11 first comes into contact with the front window screen 8 during inflation and deployment.

The airbag device 10 stores an airbag cushion 11 that is stored in front of the occupant 5 and inflates and deploys toward the occupant 5, an inflator 12 that injects inflation gas that inflates the airbag cushion 11, and the airbag cushion 11. , a storage case 13 attached to the storage part 7a, a first flap 20 wrapped around the outside of the airbag cushion 11 in the stored state, and a second flap 30 covering a part of the outside of the first flap. There is.

In this embodiment, the first flap 20 and the second flap 30 are provided doubly on the airbag cushion 11 in the stored state. The first flap 20 covers at least the open side (the side exposed from the opening 14 of the storage case 13) of the airbag cushion 11 when it is inflated and deployed. The second flap 30 is provided between the first flap 20 and the storage section 7a of the instrument panel 7 and the storage case 13.

When an impact is applied to the vehicle, such as during a vehicle collision, the inflator 12 receives a signal from a sensor and injects inflation gas, thereby starting to inflate and deploy the airbag cushion 11. The airbag cushion 11 forms an opening in the door 7b of the storage section 7a by its inflation pressure, and is inflated and deployed toward the rear of the vehicle. The airbag cushion 11 restrains the occupant 5 seated in the front passenger seat from the front.

The airbag cushion 11 is inflated and deployed to fill the space between the occupant 5 and the instrument panel 7 and front window screen 8. This prevents the occupant 5 from colliding with the instrument panel 7. It also prevents the occupant 5 from colliding with the front window screen 8, and also prevents the occupant 5 from being ejected from the vehicle.

The outside of the airbag cushion 11 in the stored state is covered by a first flap 20, as shown in FIG. 2(a). Moreover, a part of the outer surface of the first flap is covered by the second flap 30, as shown in FIG. 2(b). The configurations of the first flap 20 and the second flap 30 will be described below.

[Configuration of first flap]
The first flap 20 is a cloth material that wraps around the outside of the airbag cushion 11 in the stored state. The first flap 20 is made of, for example, a non-stretch material. The first flap 20 maintains the position and shape of the airbag cushion 11 in the stored state. The width of the first flap 20 is constant. The length of the first flap 20 is sufficient to wrap around the outer periphery of the airbag cushion 11 in a stored state that has been folded or rolled into a smaller size.

The first flap 20 has a weakened portion 21 that ruptures when pressed by the airbag cushion 11 . In this embodiment, the fragile portion 21 is constituted by a breakable slit provided in the shape of a broken line. Each slit is an elongated through hole. The weakened portion 21 extends in the width direction of the first flap 20 from one end 21a to the other end 21b. The fragile portion 21 is a portion that ruptures as the airbag cushion 11 is inflated and deployed. In the first flap 20, the strength of the weakened portion 21 is weaker than other portions, and when pressed by the airbag cushion 11 during inflation and deployment, the weakened portion 21 ruptures.

FIG. 3A shows the airbag cushion 11 with the first flap 20 wrapped around it and the airbag cushion 11 with the weakened portion 21 of the first flap 20 torn. When the weakened portion 21 ruptures, the first flap 20 is separated. The airbag cushion 11 is inflated and deployed into the vehicle interior space through the split portion of the first flap 20.

FIG. 3B is an exploded view of the airbag cushion 11 of FIG. 3A. An inflator 12 is provided inside the airbag cushion 11. The inflator 12 is a gas generator that operates upon receiving a signal from a sensor and supplies inflation gas to the airbag cushion 11. In this embodiment, a disk-shaped inflator 12 is used. A hole (not shown) is provided in the bottom surface of the airbag cushion 11 on the lower side in the drawing, and the inflator 12 is inserted through the hole. Stud bolts 16 are attached to the bottom of the inflator 12 on all sides. The stud bolt 16 passes through the first flap 20 and is fastened to the storage case 13 of the storage section 7a.

The first flap 20 is provided with a first bolt hole 24 through which the stud bolt 16 passes, and a center hole 23 at the center of which the bottom surface of the inflator 12 is exposed. The first bolt hole 24 can also be used as a connection part for connecting the first flap 20 to the airbag cushion 11. The first flap 20 is connected to the airbag cushion 11 by passing the stud bolt 16 through the first bolt hole 24 . A region of the first flap 20 having the center hole 23 and the first bolt hole 24 becomes a ground plane 22 that is in contact with the bottom of the storage section 7a.

The first flap 20 has a rectangular shape as shown in FIG. 3C(a), and the ground plane 22 is located at one end. A second bolt hole 26 is provided in the edge on the other end side of the first flap 20 in the width direction, and the first flap 20 is fixed to the ground plane 22 by passing the stud bolt 16 therethrough.

First, the first flap 20 connects the ground plane 22 to the airbag cushion 11 by passing the stud bolt 16 of the inflator 12 through the first bolt hole 24 . Next, as illustrated in FIG. 3C(b), the first flap 20 is wound around the outer surface of the airbag cushion 11 in the longitudinal direction. Then, as shown in FIG. 3C(c), the stud bolt 16 is passed through the second bolt hole 26 in the edge and fixed. This causes the first flap 20 to be wrapped around the airbag cushion 11.

In this embodiment, by wrapping the airbag cushion 11 with the first flap 20, the folding and winding of the airbag cushion 11 can be maintained, which facilitates transportation and installation of the airbag cushion 11. Furthermore, in the present embodiment, by attaching the first flap 20, the deployment behavior of the airbag cushion 11 immediately after starting inflation and deployment is stabilized, and the airbag cushion 11 is moved in the direction in which the occupant 5 is seated. can be directed to.

[Configuration of second flap]
FIG. 4(a) shows a state in which the second flap 30 of FIG. 2(b) is unfolded and laid flat on a flat surface. The second flap 30 is a cloth material that limits the amount of protrusion of the airbag cushion 11 toward the front window screen 8 during inflation and deployment. The second flap 30 is made of, for example, a non-stretch material. The second flap 30 is made of the same material as the base fabric that makes up the airbag cushion 11, for example. The second flap 30 of this embodiment is made of one piece of cloth material.

The second flap 30 includes a band portion 40 that has a required width and is formed into a straight band shape, and a widened portion 36 that is wider than the band portion 40. Both longitudinal ends of the strip portion 40 include a first end 41 and a second end 42 . The first end portion 41 and the second end portion 42 are portions to which the second flap 30 is fixed to the vehicle side, and are provided with mounting holes 41a and 42a, respectively. The first end 41 and the second end 42 having the attachment holes 41a and 42a correspond to a pair of connecting parts for fixing the second flap 30 to the vehicle side.

Specifically, the first end 41 and the second end 42 of the second flap 30 are fixed to the storage case 13 by passing the stud bolts 16 of the inflator 12 through the mounting holes 41a and 42a. Alternatively, the second flap 30 may be fixed to the storage case 13 by passing the attachment holes 41a, 42a through hooks provided at the peripheral edge of the opening 14 of the storage case 13. By fixing both ends of the second flap 30 to the vehicle side, it is possible to press the outer surface of the contact portion 11a of the airbag cushion 11 with the intermediate portion of the second flap 30. The second flap 30 limits the amount of protrusion of the airbag cushion 11 toward the front window screen 7 by pressing the outer surface of the contact portion 11a of the airbag cushion 11.

The strip portion 40 may be provided with an overlapping portion where the second flaps 30 overlap each other by being folded back a plurality of times in the length direction. The overlapping part 40 may be provided with a sewing part that sews together the fabrics of the second flaps 30 that overlap each other so that the folded state is maintained. By providing the overlapping portion, the length of the strip portion 40 can be easily adjusted.

The second flap 30 includes a band-shaped portion 40 and a widened portion 36 whose width increases in a direction intersecting the longitudinal direction of the band-shaped portion 40. The widened portion 36 is formed at an arbitrary position between the first end 41 and the second end 42 . The widened portion 36 is a portion extending in a direction intersecting the longitudinal direction of the strip portion 40. The widened portion 36 has a laterally symmetrical outer shape. The widened portion 36 may be provided at an intermediate position between the first end 41 and the second end 42, or may be provided at a position other than the intermediate position.

The second flap 30 has a region 37 that overlaps the outer surface of the contact portion 11a where the airbag cushion 11 first contacts the front window screen 8 during inflation and deployment. When the widened part 36 is provided between the first end 41 and the second end 42, as shown in FIG. Be prepared. When the widened portion 36 is provided at a position other than the middle between the first end 41 and the second end 42, as shown in FIG. Be prepared.

The second flap 30 has a breaking portion 31 that breaks when pressed by the airbag cushion 11 after the fragile portion 21 of the first flap 20 is torn. The broken portion 31 is formed at the center of the widened portion 36 in the longitudinal direction. The broken portion 31 extends in the direction in which the widened portion 36 extends. The breaking portion 31 is a portion that breaks depending on the magnitude of the tension generated between the first end 41 and the second end 42 . In the second flap 30, the strength of the breaking portion 31 is weaker than other portions, and when pressed by the inflation pressure of the airbag cushion 11, the breaking portion 31 breaks.

The second flap 30 may be made of a fabric made of the same material as the base fabric forming the airbag cushion 11. The fabric constituting the second flap 30 is formed by plain weaving of warp and weft yarns. In the present embodiment, one of the warp and weft is arranged substantially perpendicular to the direction in which the broken portion 31 is formed, and the other is arranged substantially parallel to the direction in which the broken portion 31 is formed. That is, the direction in which the warp or weft of the fabric constituting the second flap 30 is provided is substantially parallel to the direction in which the breakage portion 31 is broken. Thereby, the progression of the fracture of the fracture portion 31 can be stabilized.

The fracture portion 31 is constituted by a plurality of openings 33 formed in a direction intersecting the tension generated in the second flap 30 . In this embodiment, the openings 33 of the broken portion 31 are notches arranged linearly at required intervals.

As shown in FIG. 5A, the breaking portion 31 includes an initial breaking portion 32 at its center portion. The initial breaking portion 32 is provided in a region including the center portion 31a of the breaking portion 31. The initial breakage portion 32 is a portion that provides a starting point for the second flap 30 to break at the breakage portion 31 . The opening 33 of the initial fracture portion 32 of this embodiment is constituted by two cuts 33a having a slit width W1 of a required length and a slit interval S1. As shown in FIG. 5A, like the holes 34 and 35, the openings 33 of the initial fracture portion 32 gradually increase in size evenly on the left and right sides in the process of inflating and deploying the airbag cushion 11. After the hole 35 becomes even larger, it breaks completely.

The breaking portion 31 includes a second breaking portion 38 and a third breaking portion 39 in addition to the initial breaking portion 32 . The broken part 31 has a second broken part 38 and a third broken part 39 on both sides of the initial broken part 32. Extends to include the neighborhood. Specifically, the second breaking portion 38 is provided in a region of the widened portion 36 including the first extending portion 36a, and the third breaking portion 39 is provided in a region of the widening portion 36 including the second extending portion 36b. In this embodiment, the slit interval S1 of the initial fracture part 32 is made wider than the slit interval S2 in the second fracture part 38 and the third fracture part 39, thereby setting the strength of the initial fracture part 32 to a certain degree high, The timing at which the initial breakage portion 32 progresses to breakage is adjusted. Note that the length of the initial fracture portion 32, the slit width W1, the slit interval S1, the number of slits, etc. are changed as appropriate depending on conditions such as the capacity of the airbag cushion 11 and the gas pressure of the inflator 12.

[Action of the second flap]
Next, we will discuss the structure of the storage section 7a of the instrument panel 7 in which the airbag cushion 11 in the stored state is arranged, and the front window of the airbag cushion 11 due to the action of the second flap 30 in the process of inflating and deploying the airbag cushion 11. A method for limiting the amount of protrusion into the screen 8 (the length of the portion indicated by arrow E in FIG. 1B) will be described.

The storage section 7a has a rectangular internal space. The storage case 13 is attached by passing the attachment part 15 of the opening 14 through the through hole 7d, as shown in FIG. 6(a). The storage case 13 stores the airbag cushion 11 in a stored state, which is wrapped with a first flap 20 and a second flap 30.

An airbag cushion 11 and an inflator 12 are attached to the bottom plate of the storage case 13 with stud bolts 16. A rectifier cloth (not shown) is arranged inside the airbag cushion 11 to regulate the flow of gas injected from the inflator 12.

The door portion 7b is provided with a groove portion 7c that allows the door portion 7b to be opened, and an opening is formed by the pressure of the airbag cushion 11 that has started to inflate and deploy. In the stored state, the fragile portion 21 of the first flap 20 and the broken portion 31 of the second flap 30 face the door portion 7b.

FIG. 6(b) shows the state immediately after the airbag cushion 11 starts to inflate and deploy. When the airbag cushion 11 starts to inflate, the weakened portion 21 ruptures due to the inflation pressure, and the upper surface 25 of the first flap 20 separates into a first piece 25a and a second piece 25b. The airbag cushion 11 passes between the separated first piece 25a and second piece 25b and between the open lid portion 7b, and begins to inflate and deploy toward the vehicle interior space.

FIG. 7 is a diagram schematically showing a process in which the airbag cushion 11 is inflated and deployed after the fragile portion 21 of the first flap 20 is torn. As the airbag cushion 11 is inflated and deployed, the contact portion 11a bulges out to directly face the front window screen 8, as shown in FIG. 1B.

In the initial regulation stage (see FIG. 7(a)), the second flap 30 prevents the contact portion 11a of the airbag cushion 11 from contacting the front window screen 8 with the broken portion 31 of the second flap 30 not broken. This is a state in which the amount of protrusion is regulated.

The first breakage stage (see FIG. 7(b)) is a state in which the breakage of the opening 33 of the initial breakage portion 32 has progressed to a certain extent. When the airbag cushion 11 is inflated and deployed, a predetermined tension is applied to the second flap 30, and the initial breakage portion 32 first breaks. At the first breakage stage, the amount of protrusion of the contact portion 11a of the airbag cushion 11 toward the front window screen 8 is still regulated by the second flap 30.

The second breakage stage (see FIG. 7(c)) is a state in which the breakage has progressed to the second breakage portion 38 and the third breakage portion 39. Even in the second breakage stage, the amount of protrusion of the contact portion 11a of the airbag cushion 11 toward the front window screen 8 is still regulated by the second flap 30.

In the separation stage (see FIG. 7D), the breakage of the breakage portion 31 reaches both ends of the widened portion 36 in the extending direction, and the second flap 30 is completely broken. In the separation stage, the amount of protrusion of the contact portion 11a of the airbag cushion 11 toward the front window screen 8 is not regulated.

The second flap 30 can appropriately suppress the amount of protrusion of the airbag cushion 11 toward the front window screen 8 by appropriately adjusting its length and the configuration of the opening 31 of the fractured portion 31. The second flap 30 is configured to break when the airbag cushion 11 is further inflated and deployed and the tensile force increases after the amount of protrusion of the airbag cushion 11 toward the front window screen 8 has been suppressed. Specifically, in this embodiment, the breaking portion 31 is configured to break near the timing when the airbag cushion 11 that is being inflated and deployed comes into contact with the front window screen 8 .

Here, "near the timing of contact" means that, when the time at which the airbag cushion 11 contacts the front window screen 8 is T, the fractured portion 31 occurs within several tens of milliseconds before and after that time T. It means to break. Therefore, "near the timing of contact" includes a case where the airbag cushion 11 that is being inflated and deployed breaks immediately after it starts to contact the front window screen 8, and a case where the airbag cushion 11 breaks into the front window screen 8. This also includes cases where it breaks just before contact. In either case, the speed at which the airbag cushion 11 expands toward the front window screen 8 is suppressed, and the load applied to the front window screen 8 when the expanded airbag cushion 11 contacts the front window screen 8 is reduced. be able to.

The second flap 30 limits the amount of protrusion of the airbag cushion 11 toward the front window screen 8 during the initial restriction stage, the first breaking stage, and the second breaking stage. When the contact portion 11a of the airbag cushion 11 and the front window screen 8 at least start to come into contact with each other, the breakage portion 31 completely breaks, resulting in a separation stage.

The second flap 30 does not separate until the contact portion 11a starts contacting the front window screen 8, and maintains the connected state to prevent the airbag cushion 11 from expanding toward the front window screen 8 due to the tension of the second flap 30. It may also be controlled. This prevents the second flap 30 from being cut off before the contact portion 11a reaches the front window screen 8, thereby preventing the effect of reducing the load applied to the front window screen 8 from decreasing.

[Effects of this embodiment]
For example, when a shock is applied to the vehicle, such as during a vehicle collision, the inflator 12 receives a signal from a sensor and injects inflation gas, thereby starting to inflate and deploy the airbag cushion 11. In the airbag device 10, the first flap 20 is first pushed outward by the inflation pressure of the airbag cushion 11 and breaks at the weakened portion 21. Furthermore, the storage section 7a is pushed outward by the inflation pressure of the airbag cushion 11 and ruptures at the door section 7b. Then, the airbag cushion 11 expands outward from the opening of the storage section 7a. Thereafter, the second flap 30 is pushed outward by the inflation pressure of the airbag cushion 11, and the second flap 30 expands. The amount of projection to the screen 8 is limited. As a result, compared to an airbag device that does not have the second flap 30, the impact that the inflated and deployed airbag cushion 11 gives to the front window screen 8 is reduced.

In this embodiment, both the first flap 20 and the second flap 30 are provided outside the airbag cushion 11. In the second flap 30, both ends (first end 41 and second end 42) of the band-shaped portion 40 are fixed to the vehicle side, and the second flap 30 has a widened portion 36 in a loop-shaped middle portion. The widened portion 36 includes a region 37 that overlaps with the outer surface of the contact portion 11a where the airbag cushion 11 and the front window screen 8 come into contact. Therefore, unlike conventional airbag devices, no restrictions are placed on the installation position of the rectifying cloth provided inside the airbag cushion 11. According to this embodiment, it is possible to arrange the rectifier cloth at an optimal position and to reduce the load applied to the front window screen 8 from the inflated and deployed airbag cushion 11.

In this embodiment, in addition to the second flap 30, the first flap 20 is provided. Since the airbag cushion 11 is stored in the storage case 13 in a folded and compressed state, if the first flap 20 were not present, the second flap 30 would be pressed by the compression reaction force of the airbag cushion 11. Become. On the other hand, the length of the second flap 30 is longer than the first flap 20, and if necessary, a length adjusting section such as a folded section is provided so that the second flap 30 can be attached in a relatively loosely tensioned or relaxed state. Therefore, when pushed by the compression reaction force of the airbag cushion 11, the second flap 30 may loosen and the breakage portion 31 may not break at or near the expected breakage position. In this embodiment, by providing the first flap 20, it is possible to suppress the second flap 30 from being pushed and loosened by the above-mentioned compression reaction force.

[First modification of embodiment]
In this modification, the opening 33 of the initial fracture portion 32 of the second flap 30 is changed into various shapes.

For example, the opening 33 of the initial fracture portion 32 may be configured not only by a simple cut 33a but also by a slit 33b having a certain width (see FIG. 5B). In this case as well, by making the slit interval S1 of the initial fracture part 32 wider than the slit interval S2 of the second fracture part 38 and the third fracture part 39, the speed at which the fracture of the initial fracture part 32 progresses is slowed to a certain extent. can do.

The opening 33 of the initial fracture portion 32 may be a pinhole 33c (see FIG. 5C), or may be a polygonal small hole.

Specifically, the polygonal opening 33 may be a quadrilateral 33d or a triangle 33e (see FIGS. 5D and 5E). In this case, the polygonal openings 33d and 33e have their corner portions 33da and 33ea continuous with the broken portion 31. By making the corner portions 33da and 33ea continuous with the fracture portion 31, the fracture can proceed smoothly from the initial fracture portion 32 to the second fracture portion 38 and from the initial fracture portion 32 to the third fracture portion 39.

The shape of the opening 33 may be circular 33f or elliptical 33g (see FIGS. 5F and 5G). Moreover, when the opening 33 is formed by a cut, the slit interval S1 may be the same as the slit interval S2 in the second fracture part 38 and the third fracture part 39 (see FIG. 5H).

In any of the modified examples, the same effects as in the present embodiment described above can be obtained, so an optimal configuration may be adopted as appropriate depending on various conditions. In addition, in the embodiment of FIG. 5A, it was explained that the slit interval S1 of the initial fracture part 32 is made wider than the slit interval S2 of the second fracture part 38 and the third fracture part 39. Similarly, in the above-mentioned modified example in which the shape is circular or circular, the distance between adjacent openings 33 in the initial fracture part 31 of the second flap 30 is the same as the distance between the adjacent openings in the fracture parts 38 and 39 other than the initial fracture part 31. It may be wider than the distance between the holes 30. By setting the strength of the initial fracture portion 32 to a certain level, the speed at which the initial fracture portion 32 breaks can be adjusted.

[Second modification of embodiment]
In this modification, a storage case 13 having a shape as shown in FIGS. 8 and 9 is attached to the storage section 7a. The storage case 13 is a box shaped with a horizontally long opening 14 through which the airbag cushion 11, which is inflated and deployed by inflation gas, pops out.

The storage case 13 includes a front plate 13a, a rear plate 13b facing the front plate 13a, a bottom plate 13c extending between the lower end of the front plate 13a and the lower end of the rear plate 13b, and the front plate 13a in the left-right direction. It is a box body that includes a pair of side plates 13d extending between the end of the rear plate 13b and the end of the rear plate 13b.

In the storage case 13, a plurality of hooks 17a and 17b are provided on the outer surface of the front plate 13a and the outer surface of the rear plate 13b, respectively. Each of the hooks 17a, 17a is formed such that its tip faces toward the bottom plate 13c, and is disposed near the outside of the edge of the opening 14. The bottom plate 13c is provided with a screw hole 18 into which a stud bolt 16 of the inflator 12 is fastened.

The storage case 13 is attached to the storage section 7a by a plurality of hooks 17a on the front plate 13a and a plurality of hooks 17b on the rear plate 13b. A plurality of through holes 7d are formed in the storage portion 7a, into which a plurality of hooks 17a, 17b are inserted during installation.

In this modification, the hooks 17a and 17b are used to attach the storage case 13 to the vehicle body, but the hooks 17a and 17b can also be used to attach the first flap 20 and the second flap 30. Thereby, the configuration of the airbag device 10 can be simplified. In addition, in this modification, since the hooks 17a and 17b are composed of three or more hooks, when the first flap 20 and the second flap 30 are pressed by the airbag cushion 11, deformation is unlikely to occur, and breakage is expected. At or near the position, the fragile portion 21 and the fracture portion 31 can be caused to break during the stable period.

In this modification, both the hooks 17a and 17b are arranged near the edge of the opening 14, but only one of the hooks 17a and 17b may be arranged near the edge of the opening 14. .

[Other variations]
In the embodiments described above, the airbag device 10 is not limited to the passenger seat, but may be provided for the driver's seat.

In the embodiment described above, the material constituting the first flap 20 and the second flap 30 is not limited to the base fabric used for the airbag cushion 11, but is capable of withstanding a predetermined tension and is environmentally resistant. Other elastomers, resin materials, etc. may be used as long as they have properties.

In the embodiments described above, the second flap 30 may be provided inside the first flap 20. The second flap 30 is attached to the outside of the folded airbag cushion 11, and the first flap 20 is wrapped around the outside of the second flap 30. In this case, when the fragile portion 21 of the first flap 20 is torn, the upper surface 25 is separated into the first piece 25a and the second piece 25b, and the second flap 30 extends from the inside of the first piece 25a and the second piece 25b. The amount of protrusion of the airbag cushion 11 toward the front window screen 8 is regulated.

In the above-described embodiment, the broken portion 31 of the second flap 30 may be configured with a smaller number of layers of cloth than the number of layers of cloth in the area other than the broken portion 31 . Specifically, as shown in FIG. 10, the band-shaped portion 40 is constructed by overlapping two pieces of cloth 40a and 40b and sewing the periphery thereof by sewing 40c, while the widened portion 36 including the broken portion 31 is made of one piece. It may be made of cloth. Alternatively, the number of overlapping cloths for the belt-shaped portion 40 may be three, and the number of overlapping cloths for the broken portion 31 may be two. By providing a difference in the number of stacked cloths, the timing at which the breakage of the breakage portion 31 is completed can be adjusted.

In the above-described embodiment, the second flap 30 does not need to be a single piece of cloth material, and may have a structure in which two pieces of cloth are sewn together at the sewing part.

In the above modification, the breaking part 31 may be a sewn part that integrates two pieces of cloth without providing the opening 31. In this case, the strength of the sewn portion is determined when, after the second flap 30 suppresses the amount of protrusion of the airbag cushion 11 toward the front window screen 8, the airbag cushion 11 further expands and deploys and the tensile force increases. The strength is such that the airbag cushion 11 breaks almost at the same time as it comes into contact with the front window screen 8.

INDUSTRIAL APPLICATION This invention is applicable to the airbag apparatus etc. which protect an occupant from the front.

1 Seat 5 Passenger 7 Instrument panel 7a Storage part 8 Front window screen 10 Airbag device 11 Airbag cushion 11a Contact part 12 Inflator 13 Storage case 20 First flap 21 Fragile part 30 Second flap 31 Breaking part 32 Initial breakage part 33 Opening 36 Width part 37 Area that overlaps with the outer surface of the contact part 38 Second broken part 39 Third broken part 40 Band-shaped part 41 First end (pair of connecting parts)
42 Second end (pair of connections)

Claims (18)

folded airbag cushion,
an inflator that injects inflation gas to inflate the airbag cushion;
a first flap that covers at least an open side of the airbag cushion when it is inflated and deployed, and splits when pressed by the airbag cushion that is being inflated and deployed;
a second flap that is provided on the outside or inside of the first flap and limits the amount of protrusion of the airbag cushion toward the front window screen during inflation and deployment;
The second flap has a breakage portion that breaks when pressed by the airbag cushion during inflation and deployment, and the breakage portion is an initial breakage portion that provides a starting point for the second flap to break at the breakage portion. Equipped with an airbag device. The airbag device according to claim 1, wherein the breaking portion is formed by an opening. The airbag device according to claim 1 or 2, wherein the initial breakage portion is provided in a region including a central portion of the breakage portion. The airbag device according to claim 3, wherein the opening in the initial fracture portion is formed by a cut, a pinhole, or a slit having a predetermined width. The airbag device according to claim 3, wherein the shape of the opening in the initial fracture portion is a circle, an ellipse, or a polygon. The airbag device according to claim 5, wherein a corner portion of the polygonal opening is continuous with the fracture portion. The airbag device according to claim 1 or 2, wherein the breaking portion is configured to break near the timing when the airbag cushion that is being inflated and deployed comes into contact with a front window screen. The second flap has a band-shaped portion and a widened portion whose width increases in a direction intersecting the longitudinal direction of the band-shaped portion, and the breaking portion is provided in the widened portion. 2. The airbag device according to 2. The airbag device according to claim 8, wherein the widened portion includes a region that overlaps with an outer surface portion of a contact portion where the airbag cushion and the front window screen come into contact with each other during inflation and deployment. The broken part has a second broken part and a third broken part on both sides of the initial broken part, and the second broken part and the third broken part extend at both ends of the widened part in the extending direction or in the vicinity thereof. 9. The airbag device of claim 8, wherein the airbag device extends to a region containing the airbag. The opening in the initial fracture part is a cut or a slit having a required width, and the interval between the cuts or the slit is longer than the interval between the cuts in the second fracture part and the third fracture part. The airbag device according to item 10. The second flap includes a region that overlaps with an outer surface of a contact portion where the airbag cushion contacts the front window screen during inflation and deployment, and a pair of connection portions for fixing the second flap to the vehicle side. The airbag device according to claim 1 or 2. The first flap has a weakened portion that ruptures when pressed by the airbag cushion during inflation and deployment, and the rupture portion of the second flap ruptures after the weakened portion ruptures. airbag equipment. The airbag device according to claim 1 or 2, wherein the first flap is provided so as to wrap around the airbag cushion in a stored state. 3. The airbag cushion according to claim 1, further comprising a storage case that stores an airbag cushion in a stored state and is attached to a storage section of an instrument panel, and the first flap and the second flap are fixed to the storage case. The airbag device described. The airbag device according to claim 1 or 2, wherein the second flap is made of a woven fabric, and the direction in which the warp or weft of the woven fabric is provided is substantially parallel to the breaking direction of the breaking portion. Claim 1, wherein the distance between the adjacent openings at the initial breakage portion of the second flap is wider than the distance between the adjacent openings at a breakage portion other than the initial breakage portion. or the airbag device described in 2. The airbag device according to claim 1 or 2, wherein the broken portion of the second flap is configured with a smaller number of layers of cloth than the number of layers of cloth in an area other than the broken portion.

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