Airbag device

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

[Technical field]

[0001] The present invention relates to an airbag device or the like that restrains an occupant seated in a passenger seat or a driver's seat from the front. [Background technology]

[0002] In recent years, electric vehicles have become more and more popular. Electric vehicles no longer have an engine located at the front of the vehicle, and as shown in Figs. 11(a) and (b), there is a tendency for instrument panels 7 to become smaller. A contact portion 102 indicates a portion where an airbag cushion 101 first comes into contact with a front windscreen 8 during inflation and deployment. When the instrument panel 7 becomes smaller, a distance D from the upper surface of the instrument panel 7 to the contact portion 102 becomes shorter.

[0003] Therefore, in the airbag device 100, the airbag cushion 101 may come into contact with the front windscreen 8 immediately after being inflated and deployed, and the front windscreen 8 may be damaged by the impact caused by the load applied from the airbag cushion 101.

[0004] Conventionally, in order to address the above-mentioned problems, Patent Document 1 discloses a configuration in which a tether is stretched inside the airbag cushion 101. The tether stretched inside the airbag cushion 101 connects between the mounting opening of the inflator and the inner surface of the contact part 102, and has a means for gradually extending its length. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2014-133485 A Summary of the Invention [Problem to be solved by the invention]

[0006] Generally, the airbag cushion of an airbag device is often provided with a flow straightening fabric inside. The flow straightening fabric is a member that straightens the flow of gas injected from the inflator, and by providing the flow straightening fabric in an optimal position, it is possible to stabilize the behavior of the airbag cushion when it is inflated and deployed.

[0007] However, in the configuration of the airbag device of Patent Document 1, the tether provided inside the airbag cushion is likely to restrict the installation position of the current regulating cloth.

[0008] The present invention has been made in consideration of the above circumstances, and has an object to provide an airbag device which reduces the load applied to the front windscreen from the inflated and deployed airbag cushion, and which does not impose any restrictions on the installation position of the flow straightening cloth. [Means for solving the problem]

[0009] In order to solve the above-mentioned problems, the airbag device of the present invention comprises a folded airbag cushion, an inflator that injects inflation gas to inflate the airbag cushion, a first flap that covers at least the open side of the airbag cushion when inflated and deploys and that tears open when pushed by the airbag cushion during inflating and deploying, and a second flap that is provided on the outside or inside of the first flap and that limits the amount of protrusion of the airbag cushion toward the front windscreen during inflating and deploying, the second flap has a breaking portion that breaks when pushed by the airbag cushion during inflating and deploying, and the breaking portion has an initial breaking portion that serves as a starting point for the second flap to break at the breaking portion.

[0010] In the present invention, the breaking portion may be formed by an aperture.

[0011] In the present invention, a configuration may be adopted in which the initial rupture portion is provided in a region including the center of the rupture portion.

[0012] In the present invention, the opening of the initial rupture portion may be formed by a cut, a pinhole, or a slit having a required width.

[0013] In the present invention, the shape of the opening of the initial rupture portion may be a circle, an ellipse, or a polygon.

[0014] In the present invention, the initial break portion may be configured such that the corners of a polygonal opening are continuous with the break portion.

[0015] In the present invention, the breaking portion of the second flap may be configured to break around the timing when the airbag cushion contacts the front windshield screen during inflation and deployment.

[0016] In the present invention, the second flap may have 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 may be provided in the widened portion.

[0017] In the present invention, the widened portion may have a configuration including an area overlapping an outer surface of a contact portion where the airbag cushion comes into contact with the front windscreen during inflation and deployment.

[0018] In the present invention, the breaking portion may have a second breaking portion and a third breaking portion on either side of the initial breaking portion, and the second breaking portion and the third breaking portion may extend to both ends of the extension direction of the widening portion or to an area including the vicinity thereof.

[0019] In the present invention, the opening of the initial rupture portion may be a cut or a slit having a required width, and the spacing between the cuts or slits may be longer than the spacing between the cuts in the second rupture portion and the third rupture portion.

[0020] In the present invention, the second flap may be configured to have an area that overlaps the outer surface of the contact portion where the airbag cushion comes into contact with the front windscreen during inflation and deployment, and a pair of connecting portions for fixing the second flap to the vehicle side.

[0021] In the present invention, the first flap may have a weakened portion that tears when pressed by the airbag cushion during inflation and deployment, and a breaking portion of the second flap may break after the weakened portion tears.

[0022] In the present invention, the first flap may be configured to wrap around the periphery of the airbag cushion in the stored state.

[0023] In the present invention, a configuration may be adopted in which a storage case is provided for storing the airbag cushion in a stored state and is attached to a storage portion of the instrument panel, and the first flap and the second flap are fixed to the storage case.

[0024] 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 arranged may be substantially parallel to the breaking direction of the breaking portion.

[0025] In the present invention, a configuration may be adopted in which the distance between adjacent apertures in the initial tear portion of the second flap is wider than the distance between adjacent apertures in tear portions other than the initial tear portion.

[0026] In the present invention, a configuration may be adopted in which the number of overlapping layers at the breaking portion of the second flap is less than the number of overlapping layers of fabric in the area other than the breaking portion. Effect of the Invention

[0027] In the present invention, a first flap is provided that covers at least the open side of the airbag cushion when inflated and deployed in the stored state and breaks open when pressed by the airbag cushion during inflation and deployment, and a second flap is provided on the outer side or inner side of the first flap and limits the amount of protrusion of the airbag cushion during inflation and deployment onto the windshield screen. The second flap has a breaking portion that breaks when pressed by the airbag cushion during inflation and deployment, and the breaking portion has an initial breaking portion that provides a starting point for the second flap to break at the breaking portion. When inflation gas is injected from the inflator, the airbag cushion starts to inflate and deploy, and the first flap breaks open first. After that, the second flap limits the amount of protrusion of the airbag cushion into the windshield screen until the second flap spreads and breaks at the breaking portion. This reduces the impact of the inflated airbag cushion on the windshield screen compared to an airbag device that does not have a second flap.

[0028] In the present invention, both the first flap and the second flap are provided outside the airbag cushion. The second flap may have, for example, an area that overlaps with the outer surface of the contact portion where the airbag cushion contacts the front windscreen during inflation and deployment, and a pair of connecting portions for fixing the second flap to the vehicle side. The configuration of the present invention does not impose any restrictions on the installation position of the current rectifying cloth provided inside the airbag cushion. According to the present invention, the current rectifying cloth can be disposed in an optimal position, and the load applied to the front windscreen from the inflated and deployed airbag cushion can be reduced. [Brief description of the drawings]

[0029] [Figure 1A] FIG. 1A is a schematic configuration diagram of an airbag device according to an embodiment, as viewed from the side, in a state where the airbag device is attached to a vehicle. [Figure 1B] FIG. 1B is a diagram showing the state immediately before the airbag cushion of FIG. 1A is inflated and deployed and comes into contact with the front windshield screen. [Diagram 2]FIG. 2(a) is an oblique view of the airbag device according to the embodiment, showing a state in which a first flap is wrapped around the outside of a folded airbag cushion, and FIG. 2(b) is an oblique view of a state in which a second flap is attached to the outside of the first flap. [Figure 3A] FIG. 3A is a perspective view of the airbag cushion with the first flap wrapped around it in FIG. 2(a) and the airbag cushion with the first flap torn open, as viewed obliquely. [Figure 3B] FIG. 3B is an exploded view of the airbag cushion and a developed view of the first flap in FIG. 2(a). [Figure 3C] 3C(a) to 3C(c) are diagrams showing a process of wrapping the first flap around the airbag cushion. [Figure 4] FIG. 4(a) is a diagram showing the second flap of FIG. 2(b) laid flat and viewed from above, and FIG. 4(b) is a diagram showing another example of the second flap. [Figure 5A] FIG. 5A(a) is a diagram showing a state in which the rupture of the rupture portion of the second flap progresses in the airbag device according to the embodiment, and FIG. 5A(b) is an enlarged view of the rupture portion. [Figure 5B] FIG. 5B(a) is a diagram showing the state in which the rupture of the second flap progresses in an airbag device according to a modified embodiment (in which the initial rupture portion is a wide slit), and FIG. 5B(b) is an enlarged view of the rupture portion. [Figure 5C] FIG. 5C is a diagram showing a state in which the rupture of the second flap progresses in an airbag device according to a modified example of the embodiment (in which the initial rupture portion is a pinhole). [Figure 5D] FIG. 5D is a diagram showing a state in which the rupture of the second flap progresses in an airbag device according to a modified example of the embodiment (in which the initial rupture portion is rectangular). [Figure 5E] FIG. 5E is a diagram showing a state in which the rupture of the second flap progresses in an airbag device according to a modified example of the embodiment (in which the initial rupture portion is triangular). [Figure 5F]FIG. 5F is a diagram showing a state in which the rupture of the second flap progresses in an airbag device according to a modified example of the embodiment (in which the initial rupture portion is circular). [Figure 5G] FIG. 5G is a diagram showing a state in which the rupture of the second flap progresses in an airbag device according to a modified example of the embodiment (in which the initial rupture portion is elliptical). [Figure 5H] FIG. 5H is a diagram showing a state in which the breaking of the second flap progresses in an airbag device according to a modified example of the embodiment (wherein the initial breaking portion is a slit similar to the second breaking portion and the third breaking portion). [Figure 6] 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. [Figure 7] Figure 7(a) shows the initial restriction stage by the second flap, Figure 7(b) shows the first breaking stage by the second flap, Figure 7(c) shows the second breaking stage by the second flap, and Figure 7(d) shows the separation stage where the second flap is completely broken. [Figure 8] FIG. 8 is a perspective view showing a modified example of the storage case. [Figure 9] FIG. 9 is a side view of the storage case of FIG. 8 attached to a storage section of an instrument panel. [Figure 10] FIG. 10(a) is a plan view, and FIG. 10(b) is a cross-sectional view taken along line AA. FIG. 10(a) shows a modified example in which the breaking portion of the second flap is made of a single piece of cloth, and the band-shaped portion is made of two overlapping pieces of cloth. [Figure 11] FIG. 10(a) is a side view of the airbag cushion of a conventional airbag device in a gasoline vehicle after inflation and deployment is complete, and FIG. 10(b) is a side view of the airbag cushion of a conventional airbag device in an electric vehicle after inflation and deployment is complete. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Note that the following embodiment is merely an example of the present invention, and is not intended to limit the scope of the present invention, its applications, or its uses.

[0031] This embodiment is an airbag device 10 for protecting an occupant 5 seated in 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 disposed within an instrument panel 7 of the vehicle, and when an impact is applied to the vehicle during a collision or the like, an airbag cushion 11 inflates and deploys toward the occupant 5 to restrain the head, chest, abdomen, etc. of the occupant 5 from the front.

[0032] In the present invention, the term "occupant" refers to, for example, a person having a physique equivalent to that of an average man in the United States, conforming to a dummy for frontal collision tests (Hybrid III AM50 / frontal collision test dummy determined by the NHTSA [National Highway Traffic Safety Administration] standard [49CFR Part572 Subparts E and O]), with approximate dimensions of 175 cm in height, 88 cm in seated height, and 78 kg in weight. However, the present invention is also applicable to other anthropomorphic dummies.

[0033] In this specification, "upper" and "upper side" may refer to the head direction of an occupant 5 seated in the correct position on the seat 1, and "lower" and "lower side" may refer to the foot direction of the occupant 5. Here, the "correct position" refers to the center position in the left-right direction of the seat cushion 2 of the seat 1, where the back of the occupant 5 touches the backrest 3 from above and below. Additionally, "front" and "front side" may refer to the front direction of the occupant 5 seated in the correct position on the seat 1, and "rear" and "rear side" may refer to the back direction of the occupant 5.

[0034] As shown in Fig. 1A, the seat 1 includes a seat cushion 2 and a backrest 3. A headrest 4 is attached to the upper end of the backrest 3 via a rod-shaped support member 6. The backrest 3 and the headrest 4 of the seat 1 may be integrally formed.

[0035] As shown in Fig. 1A, the airbag device 10 is disposed inside a storage section 7a provided in a passenger seat panel of an instrument panel 7. The passenger seat panel is a panel disposed in front of the passenger seat. The airbag cushion 11 is folded or rolled up into a small stored state and stored in the storage section 7a. A storage case 13 for the airbag device 10 is attached to the storage section 7a.

[0036] When the airbag cushion 11 is in a non-inflated state before being inflated and deployed, the opening of the storage section 7a is closed by a door section 7b provided on the instrument panel 7. The front windshield screen 8 is located on an extension line of the normal direction of the opening surface of the storage section 7a. The front windshield screen 8 is a plate member provided on the front window of the vehicle, and is provided at an angle toward the passenger compartment with respect to the upper surface of the instrument panel 7.

[0037] 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 windscreen 8. A contact portion 11a indicates a portion where the airbag cushion 11 first comes into contact with the front windscreen 8 during inflation and deployment.

[0038] The airbag device 10 includes 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 sprays inflation gas to inflate the airbag cushion 11, a storage case 13 that stores the airbag cushion 11 and is attached to the storage section 7a, a first flap 20 that is wrapped around the outside of the airbag cushion 11 in the stored state, and a second flap 30 that covers part of the outside of the first flap.

[0039] In this embodiment, a first flap 20 and a second flap 30 are provided doubly for 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 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.

[0040] When the vehicle is subjected to an impact, such as during a vehicle collision, the inflator 12 receives a signal from a sensor and injects inflation gas, thereby starting the inflation and deployment of the airbag cushion 11. The airbag cushion 11 forms an opening in the door portion 7b of the storage portion 7a by the inflation pressure, and inflates and deploys toward the rear of the vehicle. The airbag cushion 11 restrains the occupant 5 seated in the passenger seat from the front.

[0041] The airbag cushion 11 inflates and deploys so as to fill the spaces between the occupant 5 and the instrument panel 7 and the front windshield 8. This prevents the occupant 5 from colliding with the instrument panel 7. It also prevents the occupant 5 from colliding with the front windshield 8, and also prevents the occupant 5 from being thrown out of the vehicle.

[0042] As shown in Fig. 2(a), the outside of the airbag cushion 11 in the stored state is covered by a first flap 20. Also, as shown in Fig. 2(b), a part of the outer surface of the first flap is covered by a second flap 30. The configurations of the first flap 20 and the second flap 30 will be described below.

[0043] [First flap configuration] The first flap 20 is a fabric 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 long enough to wrap around the outer periphery of the airbag cushion 11 in the stored state that has been compactly folded or rolled up.

[0044] The first flap 20 has a fragile portion 21 that tears when pressed by the airbag cushion 11. In this embodiment, the fragile portion 21 is configured with a breakable slit provided in a broken line. Each slit is a long and thin through hole. The fragile 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 tears when the airbag cushion 11 inflates and deploys. In the first flap 20, the strength of the fragile portion 21 is weaker than other portions, and the fragile portion 21 tears when pressed by the airbag cushion 11 during inflation and deployment.

[0045] 3A shows the airbag cushion 11 wrapped with the first flap 20 and the airbag cushion 11 in a state where the weak portion 21 of the first flap 20 has been torn. When the weak portion 21 is torn, the first flap 20 is divided. The airbag cushion 11 inflates and deploys into the vehicle interior space through the torn portion of the first flap 20.

[0046] Fig. 3B is an exploded view of the airbag cushion 11 in Fig. 3A. An inflator 12 is provided inside the airbag cushion 11. The inflator 12 is a gas generating device 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 figure, and the inflator 12 is inserted through the hole. Stud bolts 16 are attached to the bottom of the inflator 12 on all four sides. The stud bolts 16 penetrate the first flap 20 and are fastened to the storage case 13 of the storage section 7a.

[0047] The first flap 20 is provided with a first bolt hole 24 through which the stud bolt 16 passes, and a central hole 23 at the center of the first bolt hole 24 through which the bottom surface of the inflator 12 is exposed. The first bolt hole 24 can also be used as a connection portion 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. The area of ​​the first flap 20 that has the central hole 23 and the first bolt hole 24 becomes a contact surface 22 that comes into contact with the bottom of the storage section 7a.

[0048] 3C(a), the first flap 20 is rectangular, with the ground surface 22 located on one end side. A second bolt hole 26 is provided in the width direction on the edge on the other end side of the first flap 20, and the first flap 20 is fixed to the ground surface 22 by passing the stud bolt 16 through the second bolt hole 26.

[0049] First, the stud bolt 16 of the inflator 12 is passed through the first bolt hole 24 of the first flap 20, and the contact surface 22 is connected to the airbag cushion 11. Next, as shown in FIG. 3C(b), the first flap 20 is wrapped 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 at the edge to secure the first flap 20 in place. This brings the first flap 20 into a state of being wrapped around the airbag cushion 11.

[0050] In this embodiment, by wrapping the airbag cushion 11 with the first flap 20, the airbag cushion 11 can be maintained in a folded or rolled state, facilitating transportation and installation of the airbag cushion 11. In addition, in this embodiment, by attaching the first flap 20, the deployment behavior of the airbag cushion 11 immediately after the start of inflation and deployment is stabilized, and the airbag cushion 11 can be directed in the direction in which the occupant 5 is seated.

[0051] [Second flap configuration] Fig. 4(a) shows the second flap 30 of Fig. 2(b) unfolded and laid flat on a flat surface. The second flap 30 is a fabric material that limits the amount of protrusion of the airbag cushion 11 toward the front windscreen 8 during inflation and deployment. The second flap 30 is, for example, a non-stretch material. The second flap 30 is made of, for example, the same material as the base fabric that constitutes the airbag cushion 11. The second flap 30 of this embodiment is made of a single piece of fabric material.

[0052] The second flap 30 has a required width and includes a band-shaped portion 40, which is a portion formed in a straight band shape, and an expanded portion 36, which is wider than the band-shaped portion 40. Both ends in the longitudinal direction of the band-shaped portion 40 are made up of a first end portion 41 and a second end portion 42. The first end portion 41 and the second end portion 42 are portions at which the second flap 30 is fixed to the vehicle side, and are provided with mounting holes 41a, 42a, respectively. The first end portion 41 and the second end portion 42, which have the mounting holes 41a, 42a, correspond to a pair of connecting portions for fixing the second flap 30 to the vehicle side.

[0053] 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, 42a. Alternatively, the second flap 30 may be fixed to the storage case 13 by passing hooks provided on the periphery of the opening 14 of the storage case 13 through the mounting holes 41a, 42a. By fixing both ends of the second flap 30 to the vehicle side, it becomes possible for the middle part of the second flap 30 to press the outer surface part of the contact part 11a of the airbag cushion 11. The second flap 30 presses the outer surface part of the contact part 11a of the airbag cushion 11, thereby limiting the amount of protrusion of the airbag cushion 11 to the front windscreen 7.

[0054] The belt-like portion 40 may be provided with an overlapping portion where the second flaps 30 are folded back multiple times in the length direction to overlap each other. The overlapping portion 40 may be provided with a sewing portion where the overlapping pieces of fabric of the second flaps 30 are sewn together so that the folded-back state is maintained. By providing the overlapping portion, it becomes easier to adjust the length of the belt-like portion 40.

[0055] The second flap 30 has 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 any position between the first end 41 and the second end 42. The widened portion 36 is a portion that extends in a direction intersecting the longitudinal direction of the band-shaped portion 40. The widened portion 36 has a bilaterally symmetrical outer shape. The widened portion 36 may be provided at a position intermediate between the first end 41 and the second end 42, or may be provided at a position other than the intermediate position.

[0056] The second flap 30 has a region 37 that overlaps with the outer surface of the contact portion 11a that first comes into contact with the front windshield screen 8 during inflation and deployment of the airbag cushion 11. When the widening portion 36 is provided midway between the first end 41 and the second end 42, the center of the widening portion 36 is provided with a region 37 that overlaps with the outer surface of the contact portion 11a, as shown in Fig. 4(a). When the widening portion 36 is provided at a position other than the midway between the first end 41 and the second end 42, the band-shaped portion 40 is provided with a region 37 that overlaps with the outer surface of the contact portion 11a, as shown in Fig. 4(b).

[0057] The second flap 30 has a breaking portion 31 that breaks when pushed by the airbag cushion 11 after the weak portion 21 of the first flap 20 is torn open. The breaking portion 31 is formed in the center of the longitudinal direction of the widened portion 36. The breaking portion 31 extends in the extension direction of the widened portion 36. The breaking portion 31 is a portion that breaks depending on the magnitude of the tension generated between the first end portion 41 and the second end portion 42. In the second flap 30, the strength of the breaking portion 31 is weaker than other portions, and the breaking portion 31 breaks when pushed by the inflation pressure of the airbag cushion 11.

[0058] The second flap 30 may be made of a woven fabric made of the same material as the base fabric constituting the airbag cushion 11. The woven fabric constituting the second flap 30 is formed by plain weaving warp and weft threads. In this embodiment, one of the warp threads or the weft threads is arranged approximately perpendicular to the formation direction of the breaking portion 31, and the other is arranged substantially parallel to the formation direction of the breaking portion 31. In other words, the direction in which the warp threads or the weft threads of the woven fabric constituting the second flap 30 are arranged is substantially parallel to the breaking direction of the breaking portion 31. This makes it possible to stabilize the progression of the breaking of the breaking portion 31.

[0059] The breaking portion 31 is composed of 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 breaking portion 31 are cuts arranged in a straight line at required intervals.

[0060] As shown in FIG. 5A, the breaking portion 31 has an initial breaking portion 32 in its center. The initial breaking portion 32 is provided in an area including the center portion 31a of the breaking portion 31. The initial breaking portion 32 is a portion that provides a starting point for breaking the second flap 30 at the breaking portion 31. In this embodiment, the opening 33 of the initial breaking portion 32 is composed of two slits 33a having a slit width W1 and a slit interval S1 of a required length. As shown in FIG. 5A, the openings 33 of the initial breaking portion 32, like the openings 34 and 35, gradually increase in size equally on the left and right sides during the process of inflating and deploying the airbag cushion 11, and break completely after the openings 35 become even larger.

[0061] 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 breaking portion 31 has the second breaking portion 38 and the third breaking portion 39 on both sides of the initial breaking portion 32, and the second breaking portion 38 and the third breaking portion 39 extend to a region including both ends in the extension direction of the widening portion 36 or the vicinity thereof. Specifically, the second breaking portion 38 is provided in a region including the first extending portion 36a of the widening portion 36, and the third breaking portion 39 is provided in a region including the second extending portion 36b of the widening portion 36. In this embodiment, the slit interval S1 of the initial breaking portion 32 is set wider than the slit interval S2 in the second breaking portion 38 and the third breaking portion 39, so that the strength of the initial breaking portion 32 is set to a certain degree higher, and the timing at which the breakage of the initial breaking portion 32 progresses is adjusted. The length of the initial rupture portion 32, the slit width W1, the slit interval S1, the number of slits, etc. are appropriately changed depending on conditions such as the capacity of the airbag cushion 11 and the gas pressure of the inflator 12.

[0062] [Function of the second flap] Next, we will explain the structure of the storage section 7a of the instrument panel 7 in which the airbag cushion 11 in the stored state is positioned, and the method of limiting the amount of protrusion of the airbag cushion 11 into the front windscreen 8 (the length of the portion indicated by arrow E in Figure 1B) by the action of the second flap 30 during the process of the airbag cushion 11 inflating and deploying.

[0063] The storage section 7a has a rectangular internal space. As shown in Fig. 6(a), the storage case 13 is attached by passing the attachment part 15 of the opening 14 through the through hole 7d. The storage case 13 stores the airbag cushion 11 in a stored state, which is wrapped by the first flap 20 and the second flap 30.

[0064] The airbag cushion 11 and the inflator 12 are attached to the bottom plate of the storage case 13 by stud bolts 16. Inside the airbag cushion 11, a flow straightening cloth (not shown) that straightens the flow of gas injected from the inflator 12 is arranged.

[0065] The door portion 7b is provided with a groove portion 7c that enables the door portion 7b to be torn open, and an opening is formed by the pressure of the airbag cushion 11 that has begun to inflate and deploy. In the stored state, the fragile portion 21 of the first flap 20 and the breaking portion 31 of the second flap 30 face the door portion 7b.

[0066] 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 fragile portion 21 is torn open by the inflation pressure, and the upper surface 25 of the first flap 20 is separated 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 starts to inflate and deploy toward the vehicle interior space.

[0067] 7 is a schematic diagram showing the process in which the airbag cushion 11 inflates and deploys after the fragile portion 21 of the first flap 20 is torn open. As the airbag cushion 11 inflates and deploys, the contact portion 11a bulges out so as to face the front windscreen 8, as shown in FIG. 1B.

[0068] The initial restriction stage (see Figure 7(a)) is a state in which the breaking portion 31 of the second flap 30 is not broken and the second flap 30 restricts the amount of protrusion of the contact portion 11a of the airbag cushion 11 toward the front windscreen 8.

[0069] The first rupture stage (see FIG. 7(b)) is a state in which the rupture of the opening 33 of the initial rupture portion 32 has progressed to a certain extent. As the airbag cushion 11 progresses in inflation and deployment, a predetermined tension acts on the second flap 30, and the rupture of the initial rupture portion 32 progresses first. In the first rupture stage, the amount of protrusion of the contact portion 11a of the airbag cushion 11 toward the front windscreen 8 is still regulated by the second flap 30.

[0070] In the second breaking stage (see FIG. 7(c)), the breaking has progressed to the second breaking portion 38 and the third breaking portion 39. Even in the second breaking stage, the protrusion amount of the contact portion 11a of the airbag cushion 11 toward the front windscreen 8 is still restricted by the second flap 30.

[0071] In the separation stage (see FIG. 7(d)), the breakage of the breaking portion 31 reaches both ends of the widening 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 windscreen 8 is not restricted.

[0072] The second flap 30 can appropriately suppress the amount of protrusion of the airbag cushion 11 into the front windscreen 8 by appropriately adjusting the length thereof and the configuration of the opening 31 of the breaking portion 31. The second flap 30 is configured to break when the airbag cushion 11 further inflates and deploys and the tensile force increases after the amount of protrusion of the airbag cushion 11 into the front windscreen 8 has been suppressed. Specifically, in this embodiment, the breaking portion 31 is configured to break near the timing when the airbag cushion 11 contacts the front windscreen 8 during inflation and deployment.

[0073] Here, "around the time of contact" means that, when the time at which the airbag cushion 11 comes into contact with the front windscreen 8 is T, the breaking portion 31 breaks within several tens of milliseconds before or after the time T. Therefore, "around the time of contact" includes a case where the airbag cushion 11 breaks just after it starts to come into contact with the front windscreen 8 during inflation and deployment, and also a case where the airbag cushion 11 breaks just before it comes into contact with the front windscreen 8. In either case, the speed at which the airbag cushion 11 expands toward the front windscreen 8 can be suppressed, and the load applied to the front windscreen 8 when the inflated airbag cushion 11 comes into contact with the front windscreen 8 can be reduced.

[0074] The second flap 30 restricts the amount of protrusion of the airbag cushion 11 into the windshield 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 at least starts to come into contact with the windshield screen 8, the breaking portion 31 breaks completely, entering the separation stage.

[0075] The second flap 30 may be configured not to separate until the contact portion 11a starts to contact the front windscreen 8, but to maintain the connected state and control the inflation of the airbag cushion 11 onto the front windscreen 8 by the tension of the second flap 30. This makes it possible to prevent the second flap 30 from being cut off before the contact portion 11a reaches the front windscreen 8, thereby preventing a decrease in the effect of reducing the load applied to the front windscreen 8.

[0076] [Effects of this embodiment] For example, 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 the inflation and deployment of 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 fragile portion 21. Furthermore, the storage portion 7a is pushed outward by the inflation pressure of the airbag cushion 11 and breaks at the door portion 7b. Then, the airbag cushion 11 bulges outward from the opening of the storage portion 7a. After that, the second flap 30 is pushed outward by the inflation pressure of the airbag cushion 11 and spreads, but the second flap 30 limits the amount of protrusion of the airbag cushion 11 into the front windscreen 8 until it breaks at the breaking portion 31. As a result, the impact of the inflated and deployed airbag cushion 11 on the front windscreen 8 is mitigated compared to an airbag device that does not have the second flap 30.

[0077] In this embodiment, both the first flap 20 and the second flap 30 are provided outside the airbag cushion 11. The second flap 30 has both ends (first end 41 and second end 42) of a band-shaped portion 40 fixed to the vehicle side, and has an expanded portion 36 in a looped intermediate portion, and the expanded portion 36 has an area 37 overlapping with an outer surface portion of a contact portion 11a where the airbag cushion 11 and the front windscreen 8 come into contact. Therefore, unlike the conventional airbag device, there is no restriction on the installation position of the current straightening cloth provided inside the airbag cushion 11. According to this embodiment, the current straightening cloth can be arranged at an optimal position, and the load applied to the front windscreen 8 from the inflated and deployed airbag cushion 11 can be reduced.

[0078] 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 is not provided, the second flap 30 will be pressed by the compression reaction force of the airbag cushion 11. On the other hand, the length of the second flap 30 is longer than that of the first flap 20, and if necessary, a length adjustment part such as a folded part is provided and the second flap 30 is attached in a relatively loosely stretched or slackened state. Therefore, when the second flap 30 is pressed by the compression reaction force of the airbag cushion 11, there is a risk that the second flap 30 will loosen and the breaking part 31 will not break at or near the expected breaking 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.

[0079] [First Modification of the Embodiment] In this modification, the opening 33 of the initial breaking portion 32 of the second flap 30 is changed into various shapes.

[0080] For example, the opening 33 of the initial rupture portion 32 may be configured as a slit 33b having a certain width instead of a simple cut 33a (see FIG. 5B). Even in this case, the slit interval S1 of the initial rupture portion 32 may be made wider than the slit interval S2 of the second rupture portion 38 and the third rupture portion 39, thereby slowing down the rate at which the rupture of the initial rupture portion 32 progresses to a certain degree.

[0081] The opening 33 of the initial rupture portion 32 may be configured as a pinhole 33c (see FIG. 5C), or may be a small polygonal hole.

[0082] Specifically, polygonal opening 33 may be a rectangle 33d or a triangle 33e (see Figs. 5D and 5E). In this case, corners 33da, 33ea of ​​polygonal openings 33d, 33e are made to be continuous with fracture portion 31. By making corners 33da, 33ea continuous with fracture portion 31, fracture can progress smoothly from initial fracture portion 32 to second fracture portion 38 and from initial fracture portion 32 to third fracture portion 39.

[0083] The shape of the aperture 33 may be a circle 33f or an ellipse 33g (see Figs. 5F and 5G). When the aperture 33 is formed by a cut, the slit interval S1 may be the same as the slit interval S2 in the second break portion 38 and the third break portion 39 (see Fig. 5H).

[0084] Since any of the modified examples can obtain the same effect as the present embodiment described above, an optimal configuration may be appropriately adopted depending on various conditions. In the embodiment of FIG. 5A, the slit interval S1 of the initial rupture portion 32 is described as being wider than the slit interval S2 of the second rupture portion 38 and the third rupture portion 39. Similarly, in the modified example in which the openings 33 are polygonal or circular, the distance between adjacent openings 33 in the initial rupture portion 31 of the second flap 30 may be wider than the distance between adjacent openings 30 in the rupture portions 38 and 39 other than the initial rupture portion 31. By setting the strength of the initial rupture portion 32 to a certain degree, the speed at which the rupture of the initial rupture portion 32 progresses can be adjusted.

[0085] [Second Modification of the Embodiment] In this modification, a storage case 13 having a shape as shown in Figures 8 and 9 is attached to the storage section 7a. The storage case 13 is a box having a horizontally long opening 14 formed therein through which the airbag cushion 11, which is inflated and deployed by inflation gas, pops out.

[0086] The storage case 13 is a box having a front panel 13a, a rear panel 13b facing the front panel 13a, a bottom panel 13c extending between the lower end of the front panel 13a and the lower end of the rear panel 13b, and a pair of side panels 13d extending in the left-right direction between the end of the front panel 13a and the end of the rear panel 13b.

[0087] In the storage case 13, a plurality of hooks 17a, 17b are provided on the outer surface of the front plate 13a and the outer surface of the rear plate 13b, respectively. Each hook 17a, 17a is formed so that its tip faces the bottom plate 13c, and is disposed near the outer side of the edge of the opening 14. The bottom plate 13c is provided with a screw hole 18 into which the stud bolt 16 of the inflator 12 is fastened.

[0088] 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. The storage section 7a is formed with a plurality of through holes 7d through which the hooks 17a, 17b are inserted when the storage case 13 is attached.

[0089] In this modification, the hooks 17a, 17b are used to attach the storage case 13 to the vehicle body, but the hooks 17a, 17b can also be used to attach the first flap 20 and the second flap 30. This simplifies the configuration of the airbag device 10. Also, in this modification, since the hooks 17a, 17b are composed of three or more hooks, deformation is unlikely to occur when the first flap 20 and the second flap 30 are pressed by the airbag cushion 11, and the fragile portion 21 and the breaking portion 31 can be broken in a stable period at or near the expected breaking position.

[0090] In this modification, both hooks 17a and 17b are disposed near the edge of opening 14, but only one of hooks 17a and 17b may be disposed near the edge of opening 14.

[0091] [Other variations] In the above-described embodiment, the airbag device 10 is not limited to being provided for the passenger seat, but may also be provided for the driver's seat.

[0092] In the above-described embodiment, the material constituting the first flap 20 and the second flap 30 is not limited to the base fabric used in the airbag cushion 11, but may be other elastomers, resin materials, etc., as long as they can withstand a predetermined tension and are environmentally resistant.

[0093] In the above-described embodiment, the second flap 30 may be provided on the inside of 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 weak 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 to regulate the amount of protrusion of the airbag cushion 11 toward the front windscreen 8.

[0094] In the above-described embodiment, the breaking portion 31 of the second flap 30 may be configured with fewer overlapping layers of fabric than the area other than the breaking portion 31. Specifically, as shown in FIG. 10, the band-shaped portion 40 may be configured by overlapping two pieces of fabric 40a, 40b and sewing the periphery together with stitching 40c, while the widened portion 36 including the breaking portion 31 may be configured with one piece of fabric. Alternatively, the band-shaped portion 40 may have three overlapping layers of fabric, and the breaking portion 31 may have two overlapping layers of fabric. By providing a difference in the number of overlapping layers of fabric, the timing at which the breaking of the breaking portion 31 is completed can be adjusted.

[0095] In the above-described embodiment, the second flap 30 does not have to be a single piece of fabric, but may be configured as two pieces of fabric sewn together at a seam.

[0096] In the above modified example, the breaking portion 31 may not have an opening 31, and may be a sewn portion that integrates two pieces of fabric as the breaking portion 31. In this case, the strength of the sewn portion is set to be such that the airbag cushion 11 breaks almost simultaneously with contact with the windscreen 8 when the airbag cushion 11 continues to inflate and deploy and the tensile force increases after the second flap 30 has restricted the amount of protrusion of the airbag cushion 11 into the windscreen 8. [Industrial Applicability]

[0097] The present invention is applicable to an airbag device or the like that protects an occupant from the front. [Explanation of symbols]

[0098] 1 seat 5 Crew 7. Instrument Panel 7a Storage section 8. Front Window Screen 10 Airbag device 11 Airbag cushion 11a Contact part 12 Inflator 13 Storage case 20 First flap 21 Weakened Part 30 2nd flap 31 Breaking part 32 Initial break 33 Open hole 36 Widening section 37 Area overlapping with outer surface of contact part 38 Second break 39 Third break 40 Belt 41 First end (pair of connecting parts) 42 Second end (pair of connecting parts)

Claims

1. A folded airbag cushion; an inflator that ejects inflation gas to inflate the airbag cushion; a first flap that covers at least an open side of the airbag cushion when inflated and deployed, and that tears when pushed by the airbag cushion during inflation and deployment; a second flap that is provided on the outer side or the inner side of the first flap and limits the amount of protrusion of the airbag cushion toward the front windshield screen during inflation and deployment, the second flap has a breaking portion that breaks when pushed by an airbag cushion during inflation and deployment, the breaking portion including an initial breaking portion that serves as a starting point for breaking the second flap at the breaking portion, The second flap has a band-like portion and a widened portion whose width increases in a direction intersecting a longitudinal direction of the band-like portion, and the breaking portion is provided in the widened portion.

2. The airbag device according to claim 1 , wherein the breakable portion is formed by an aperture.

3. 3. The airbag device according to claim 1, wherein the initial rupture portion is formed by an opening, and is provided in a region including a central portion of the rupture portion.

4. 4. The airbag device according to claim 3, wherein the opening of the initial rupture portion is formed by a cut, a pinhole, or a slit having a required width.

5. The airbag device according to claim 3 , wherein the opening of the initial rupture portion has a shape of a circle, an ellipse, or a polygon.

6. 6. The airbag device according to claim 5, wherein corners of the opening of the initial rupture portion, which is polygonal, are continuous with the rupture portion.

7. 3. The airbag device according to claim 1, wherein the rupture portion is configured to rupture in the vicinity of a timing at which the airbag cushion contacts a front windshield screen during inflation and deployment.

8. An airbag device as described in claim 1, wherein the widening portion includes an area that overlaps with an outer surface of a contact portion where the airbag cushion comes into contact with the front windscreen during inflation and deployment.

9. An airbag device as described in claim 1, wherein the breaking portion has a second breaking portion and a third breaking portion on either side of the initial breaking portion, and the second breaking portion and the third breaking portion extend to an area including both ends in the extension direction of the widening portion or their vicinity.

10. An airbag device as described in claim 9, wherein the opening in the initial rupture portion is a notch or a slit having a required width, and the spacing between the notches or slits is longer than the spacing between the notches in the second rupture portion and the third rupture portion.

11. An airbag device as described in claim 1 or 2, wherein the second flap has an area that overlaps the outer surface of a contact portion where the airbag cushion comes into contact with the front windshield screen during inflation and deployment, and a pair of connecting portions for fixing the second flap to the vehicle side.

12. An airbag device as described in claim 1 or 2, wherein the first flap has a weak portion that breaks when pressed by the airbag cushion during inflation and deployment, and after the weak portion breaks, the breaking portion of the second flap breaks.

13. An airbag device as described in claim 1 or 2, wherein the first flap is arranged to wrap around the airbag cushion in a stored state.

14. An airbag device as described in claim 1 or 2, 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.

15. An airbag device as described in claim 1 or 2, wherein the second flap is made of a woven fabric, and the direction in which the warp or weft threads of the fabric are arranged is substantially parallel to the breaking direction of the breaking portion.

16. The breaking portion is formed by an aperture, the initial rupture portion is formed by an opening and is provided in a region including a central portion of the rupture portion; 2. The airbag device according to claim 1, wherein a distance between adjacent apertures in the initial rupture portion of the second flap is greater than a distance between adjacent apertures in rupture portions other than the initial rupture portion.

17. An airbag device as described in claim 1 or 2, wherein the breaking portion of the second flap is composed of a number of overlapping layers of fabric that is less than the number of overlapping layers of fabric in the area other than the breaking portion.

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