Air bag device

Abstract

To provide an air bag device which can be made compact and can adequately protect an occupant.SOLUTION: When an air bag 20 inflates by flowing inflation gas therein, it inflates so as to protrude upward from a storage area 16 provided on an upper surface 2 side of an instrument panel 1 and to unfold rearward. The air bag includes a bag body 21 and an outer tether part 55 arranged on an outer peripheral surface side of the bag body. The bag body has a recess 35 that recesses upward on an underside of a region forward of an occupant side wall part 40 arranged on a rear side when inflation is completed. The outer tether part is arranged so as to connect a rear lower end 21c side of the bag body when inflation is completed and a front edge 35a side of the recess, so that the rear lower end of the bag body when inflation is completed can be arranged close to a rear surface 3 of the instrument panel.SELECTED DRAWING: Figure 12

Description

[Technical field]

[0001] The present invention relates to an airbag device that is arranged on the upper side of an instrument panel and has an airbag that can be inflated by flowing inflation gas into it, an inflator that supplies inflation gas to the airbag, and a storage area that stores the folded airbag and the inflator. [Background technology]

[0002] Conventionally, there has been an airbag device with such a configuration that is disposed in front of the passenger seat to protect the passenger seated in the passenger seat. In the passenger seat airbag device with such a configuration, when the inflator is activated, the airbag that is folded and stored in a storage portion inflates so as to protrude upward from the storage portion and deploy rearward to protect the passenger seated in the passenger seat (see, for example, Patent Document 1). In detail, the inflated airbag is configured to receive and protect the passenger moving forward by having the front side supported by the instrument panel or the windshield disposed above the instrument panel. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP2016-60390A Summary of the Invention [Problem to be solved by the invention]

[0004] However, when an airbag device of this configuration is installed in a vehicle in which the instrument panel is located at a position far forward from the front seat in which the occupant sits, the distance from the installation position of the airbag device to the occupant is large, and therefore the volume of the airbag needs to be large in order to stably support the occupant, which leads to an increase in the size of the device and manufacturing costs.

[0005] The present invention has been made to solve the above-mentioned problems, and has an object to provide an airbag device that can be made compact in configuration and can adequately protect an occupant. [Means for solving the problem]

[0006] The airbag device according to the present invention is arranged on an upper surface side of an instrument panel and includes an airbag that can be inflated by flowing inflation gas therein, an inflator that supplies inflation gas to the airbag, and a storage portion that stores the folded airbag and the inflator, In an airbag device configured such that, when inflation gas discharged from an inflator flows into the airbag and the airbag inflates, the airbag protrudes upward from a storage portion and deploys rearward, The airbag is configured to include a bag body that is inflated by flowing inflation gas therein, and an outer tether portion that is disposed on the outer peripheral surface side of the bag body and that regulates the shape of the bag body when it is fully inflated, The bag body is configured such that an occupant side wall portion capable of protecting an occupant seated in the front seat is disposed on the rear side when the bag body is fully inflated, and a recess portion is disposed on the lower surface side of a region forward of the occupant side wall portion when the bag body is fully inflated, the recess portion being recessed upward so as to provide a gap between the bag body and the instrument panel, The outer tether portion is arranged to connect the rear lower end side of the bag body when fully inflated to the front edge side of the recess, and is configured so that the rear lower end of the bag body when fully inflated can be positioned close to the rear surface of the instrument panel.

[0007] In the airbag device of the present invention, when the airbag is fully inflated, the inflated bag body is disposed in the front lower surface area so as to provide a gap between the airbag and the instrument panel, but the rear lower end side of the bag body is connected to the front edge side of the recess that forms this gap via an outer tether portion that is disposed on the outer peripheral surface side of the bag body, and is disposed close to the rear surface of the instrument panel when the airbag is fully inflated. That is, in the airbag device of the present invention, the airbag (bag body) can be inflated in a partially recessed state so as to provide a gap between the airbag and the instrument panel, so that the volume can be reduced compared to an airbag that is not provided with such a recess. The outer tether portion causes the rear lower end of the inflated bag body to be located close to the rear surface of the instrument panel, and the recess formed in the bag body is formed in an area that is forward of the occupant side wall portion that protects the occupant when inflation is complete, so that even with a configuration that includes a recess, the area on the rear lower end side of the bag body can be supported by the instrument panel, and the occupant moving forward can be stably received by the occupant side wall portion. As a result, in the airbag device of the present invention, even if the interior shape of the vehicle to which it is mounted is different, by appropriately setting the shape of the recess formed in the bag body, it is possible to suppress an increase in the volume of the airbag and also to suppress an increase in the size of the device itself.

[0008] Therefore, the airbag device of the present invention can have a compact structure and can adequately protect the occupant.

[0009] In the airbag device of the present invention, the bag body is inflated so that a protrusion that is disposed so as to partially protrude upward from the instrument panel is positioned within the recess, It is preferable that the outer tether portion is configured to be disposed adjacent to the rear surface side of the projection when the bag body is completely inflated.

[0010] With such an airbag device, even when the airbag device is installed in a vehicle having a protrusion partially protruding from the instrument panel, the provision of the recesses makes it possible to prevent the inflating bag body from significantly interfering with the protrusion, and to complete the inflation smoothly. Also, in the airbag device with the above configuration, since the outer tether portion is disposed close to the rear side of the protrusion when the bag body completes inflation, it is possible to ensure a reaction force by supporting the outer tether portion on the protrusion when the occupant is received by the occupant-side wall portion, and thus it is possible to adequately protect the occupant. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic perspective view showing an instrument panel of a vehicle in which an airbag device for a passenger seat according to an embodiment of the present invention is mounted; [Diagram 2] 1 is a schematic vertical cross-sectional view of a passenger seat airbag device according to an embodiment of the present invention mounted on a vehicle. [Diagram 3] 1 is a schematic perspective view showing a state in which an airbag used in a passenger seat airbag device according to an embodiment is inflated by itself; [Figure 4] 4 is a schematic longitudinal sectional view of the airbag of FIG. 3 taken in the front-rear direction. [Diagram 5] FIG. 4 is a plan view of the base materials constituting the airbag of FIG. 3 arranged side by side. [Figure 6] 4 is an enlarged plan view of a side wall panel that constitutes the airbag of FIG. 3. [Figure 7] 4A and 4B are plan and bottom views of a pre-folded bag formed by folding the airbag of FIG. 3. [Figure 8] 4 is a schematic diagram showing a folding process of the airbag of FIG. 3. FIG. [Figure 9] 8A to 8C are schematic diagrams showing a folding process of the airbag of FIG. 3. [Figure 10] 3A to 3C are schematic vertical cross-sectional views illustrating an inflation process of an airbag in the passenger seat airbag device according to the embodiment. [Figure 11]11A to 11C are schematic vertical cross-sectional views showing the inflation process of the airbag in the passenger seat airbag device according to the embodiment, showing the process subsequent to that in FIG. 10 . [Figure 12] 2 is a schematic vertical cross-sectional view showing a fully inflated state of the airbag in the passenger seat airbag device according to the embodiment; FIG. [Figure 13] 2 is a schematic rear view of the passenger seat airbag device according to the embodiment, showing the airbag in a fully inflated state, as viewed from the rear of the vehicle. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the embodiment, an airbag device for a passenger seat (hereinafter abbreviated as "airbag device") M arranged in front of a passenger seat as a front seat will be described as an example. As shown in Figs. 1 and 2, the airbag device M is a top-mount type arranged on an upper surface 2 side of an instrument panel (hereinafter abbreviated as "instrument panel") 1. In the embodiment, as shown in Figs. 1 and 2, a monitor 5 as a protrusion is arranged on the instrument panel 1 of a vehicle V on which the airbag device M is mounted, on the rear surface side behind the area in which the airbag device M is arranged, so as to protrude partially upward. In detail, in the case of the embodiment, the instrument panel 1 is configured so that the rear surface 3 is inclined slightly forward with respect to the vertical direction, and the monitor 5 is also arranged so as to be inclined slightly forward with respect to the vertical direction so as to be approximately along the rear surface 3 of the instrument panel 1 (see Fig. 2). In the present embodiment, the monitor 5 is formed to be slightly wider in the lateral direction than the airbag device M (more specifically, the airbag cover 10 described later) (see FIG. 1), and is disposed in a position directly facing the passenger MP seated in the passenger seat (see FIG. 13). In the present embodiment, the front-rear, up-down, and left-right directions correspond to the front-rear, up-down, and left-right directions of the vehicle V, unless otherwise specified.

[0013] As shown in Figures 2 and 12, the airbag device M is configured to include a folded airbag 20, an inflator 12 that supplies inflation gas to the airbag 20, a case 16 as a storage portion for storing the folded airbag 20 and the inflator 12, a retainer 13 for attaching the airbag 20 and the inflator 12 to the case 16, and an airbag cover 10 that covers the folded airbag 20.

[0014] In the embodiment, the airbag cover 10 is formed integrally with the instrument panel 1 made of synthetic resin, and is configured so that when the airbag 20 is deployed and inflated, the two front and rear doors 10a, 10b are pushed open by the airbag 20. In addition, a connecting wall 10c that is connected to the case 16 is formed around the doors 10a, 10b of the airbag cover 10.

[0015] As shown in FIG. 2, the inflator 12 includes a substantially cylindrical main body portion 12a having a plurality of gas discharge ports 12b, and a flange portion 12c for attaching the inflator 12 to the case 16.

[0016] The case 16 as the storage portion is made of sheet metal and formed in a substantially rectangular parallelepiped shape with a rectangular opening at the upper end side, and is configured to include a substantially rectangular plate-like bottom wall portion 16a into which the inflator 12 is inserted from below and a peripheral wall portion 16b extending upward from the outer periphery of the bottom wall portion 16a and engaging the connecting wall portion 10c of the airbag cover 10, as shown in Fig. 2. In the case of the embodiment, the airbag 20 and the inflator 12 are attached to the bottom wall portion 16a of the case 16 by fastening with nuts 14 using the bolts 13a of the retainer 13 arranged in the airbag 20 as mounting means, which penetrate the periphery of an inflow opening 30 of the airbag 20, which will be described later, the bottom wall portion 16a of the case 16, and the flange portion 12c of the inflator 12. In addition, a bracket (not shown) that is connected to the body side of the vehicle V is disposed on the bottom wall portion 16a of the case 16.

[0017] In the embodiment, as shown in Figures 3 and 4, the airbag 20 comprises a bag body 21 that is inflated by flowing inflation gas into it, front and rear tethers 45 as internal tethers that are disposed within the bag body 21 and regulate the shape of the bag body 21 when fully inflated, and an outer tether portion 55 that is disposed on the outer peripheral surface side of the bag body 21 and regulates the shape of the bag body 21 when fully inflated.

[0018] As shown in Fig. 12, the bag body 21 is configured to be arranged so as to close the gap between the upper surface 2 of the instrument panel 1 and the windshield 7 above the instrument panel 1 when the bag is fully inflated. Specifically, as shown in Figs. 3 and 4, the bag body 21 has an outer shape when the bag is fully inflated that is a substantially quadrangular pyramid shape with the apex located at the front end side and a shape in which the lower surface side is largely concave upward. The bag body 21 includes an occupant side wall portion 40 that is arranged on the rear side (rear surface side) that becomes the occupant MP side when the bag is fully inflated, and a peripheral wall portion 23 that extends from the periphery of the occupant side wall portion 40 and converges toward the front end side that is attached to the case 16 side.

[0019] The peripheral wall portion 23 is a portion that is arranged so as to mainly close the gap between the upper surface 2 of the instrument panel 1 and the windshield 7 above the instrument panel when the airbag 20 (bag body 21) is fully inflated, and includes an upper wall portion 24 and a lower wall portion 25 that are arranged so as to face each other in the vertical direction, and a left wall portion 26 and a right wall portion 27 that are arranged so as to face each other in the horizontal direction when the airbag 20 is fully inflated. In the vicinity of the front end 25a of the lower wall portion 25, at a position that is approximately in the center from the left to the right, an inflow opening 30 is formed, which opens in a substantially circular shape to allow the inflation gas to flow into the interior, and whose periphery is attached to the bottom wall portion 16a of the case 16. A plurality of (in the embodiment, four) mounting holes 31 are formed on the periphery of the inflow opening 30 for inserting the bolts 13a of the retainer 13 therethrough to attach the periphery of the inflow opening 30 to the bottom wall portion 16a of the case 16. The left wall portion 26 and the right wall portion 27 are formed with vent holes 33 that open in a substantially circular shape for discharging excess inflation gas that has flowed into the bag body 21. Each vent hole 33 is disposed in the left wall portion 26 and the right wall portion 27 at a position that is rearward and above an area where a recess 35, which will be described later, is disposed.

[0020] In the bag body 21 of the embodiment, the lower wall portion 25 is configured to be curved when viewed from the left and right direction so that the front and rear intermediate portions are located upward, and this curved shape is arranged over substantially the entire left and right area (i.e., substantially the entire left and right area of ​​the bag body 21) (see Figs. 3 and 4). In the embodiment, due to the curved shape of the lower wall portion 25, the bag body 21 is configured to have a recess 35 that is recessed upward in the lower surface area. In detail, the recess 35 is formed at a position that is substantially the center in the front and rear directions when the bag body 21 is viewed from the left and right sides when the bag body 21 is fully inflated. In other words, the recess 35 is formed on the lower surface side of the area forward of the occupant side wall portion 40, separated from the occupant side wall portion 40 arranged on the rear side of the bag body 21 in the front and rear directions. As described above, the recess 35 is continuously formed so that the recess shape is the same over substantially the entire left and right area of ​​the bag body 21. That is, by providing this recess 35, a gap is provided between the bag body 21 and the instrument panel 1 over the entire left and right area when the airbag 20 is fully inflated. Also, this recess 35 is provided at a position corresponding to the monitor 5 protruding upward on the rear surface 3 side of the instrument panel 1 when the airbag 20 is fully inflated (see FIG. 12). In other words, the bag body 21 is disposed so as to bypass the monitor 5 by the recess 35 when the airbag 20 is fully inflated.

[0021] The occupant side wall portion 40 is disposed at a position rearward of the monitor 5 on the rear end 21b side of the bag body 21 when the bag body 21 is fully inflated, and is disposed substantially along the vertical direction so as to face the occupant MP seated in the passenger seat (see FIG. 12). Specifically, as shown in FIG. 13, the occupant side wall portion 40 is configured to have an outer shape when the bag body 21 is fully inflated that is substantially rectangular in width in the vertical direction and can widely cover the front of the upper body of the occupant MP. In the case of the embodiment, the lower end 40a side of the occupant side wall portion 40 when the bag body 21 is fully inflated is positioned below the monitor 5, and the width dimension on the left and right sides is set larger than the width dimension on the left and right sides of the monitor 5, so that the occupant side wall portion 40 is configured to cover the entire vehicle rear side of the monitor 5 (see FIGS. 12 and 13). In the case of the embodiment, the bag body 21 is configured to have the upper surface side (the upper wall portion 24 side) abut against the windshield 7 when the bag body 21 is fully inflated.

[0022] The front and rear tethers 45 as internal tethers that regulate the shape of the bag body 21 after inflation are disposed so as to connect the approximate center of the occupant side wall portion 40 on the left and right sides to the front end 21a side of the bag body 21. The front and rear tethers 45 are disposed to regulate the excessive rearward protrusion of the occupant side wall portion 40 at the beginning of inflation, and to regulate the position of the occupant side wall portion 40 at the completion of inflation (the distance from the peripheral portion of the inflow opening 30). In the embodiment, the front and rear tethers 45 are configured so as to connect a front portion 46 extending from the peripheral portion of the inflow opening 30 and a rear portion 47 extending from the occupant side wall portion 40 side (see Figs. 3 and 4). In the embodiment, the front portion 46 is configured by partially folding a band-shaped front portion material 49 shown in Fig. 5 in half. The rear portion 47 has a generally trapezoidal outer shape that narrows toward the front end connected to the front portion 46. The rear portion 47 is sewn to the occupant side wall portion 40 at a position that is generally the center in the lateral direction, with the rear edge aligned in the up-down direction.

[0023] The outer tether portion 55 regulates the shape of the bag body 21 when it is fully inflated, and is disposed on the outer peripheral surface of the bag body 21 so as to connect the rear lower end 21c side of the bag body 21 when it is fully inflated (specifically, near the rear end 25b of the lower wall portion 25) to the front edge 35a side of the recess 35 (the area behind the inflow opening 30). In the embodiment, when the airbag 20 (bag body 21) is inflated alone, the outer tether portion 55 is disposed so as to cross the recess 35 as shown in Fig. 4, and when it is fully inflated while mounted on the vehicle, the outer tether portion 55 is disposed close to and generally along the rear surface 5a on the rear side of the monitor 5 as shown in Fig. 12. The outer tether portion 55 is for restricting the rear lower end 21c side (the region on the lower end 40a side of the occupant-side wall portion 40) of the bag body 21 from excessively protruding rearward and downward when the bag body 21 is deployed and inflated, and for enabling the rear lower end 21c side of the bag body 21 to be disposed close to the rear surface 3 of the instrument panel 1 when the bag body 21 is fully inflated. More specifically, the outer tether portion 55 has an upper end 55a (one end) connected to the front edge 35a side of the recess 35 when the bag body 21 is fully inflated when mounted on the vehicle. The upper end 55a of the outer tether portion 55 is connected to a portion located near the upper end 5b of the monitor 5 (see FIG. 12). The other end (lower end 55b) of the outer tether portion 55 is connected to a position (near the rear end 25b of the lower wall portion 25) near the rear edge 35b of the recess 35 and above the lower edge 21d of the bag body 21 when fully inflated (see FIG. 4). In detail, the lower end 55b of the outer tether portion 55 is connected to a position located below the monitor 5 and adjacent to the rear surface 3 of the instrument panel 1 in the bag body 21 when fully inflated when mounted on the vehicle, as shown in FIG. The length dimension L1 (see Figure 4) of this outer tether portion 55 is set so as to be approximately the same as the length dimension L2 (see Figure 5) of the straight line connecting points P1, P2 corresponding to intended connection portions 77F, 77B (see Figure 5) that will respectively connect both ends (upper end 55a, lower end 55b) of the outer tether portion 55 when the side wall panels 68 (68L, 68R) that constitute the bag body 21, which will be described later, are laid out flat.Furthermore, the outer tether portion 55 is configured to have a width dimension that is substantially equal to that of the lower wall portion 25, and more specifically, slightly smaller than that of the lower wall portion 25 (the width dimension of the peripheral wall panel 63 described later) (see FIG. 5). As described above, the outer tether portion 55 is configured to have a lower end 55b disposed at a position lower than the monitor 5 when the bag body 21 is fully inflated when mounted on the vehicle, and to widely cover substantially the entire area of ​​the rear surface 5a side of the monitor 5 in all directions when the bag body 21 is fully inflated. In the case of the embodiment, the outer tether portion 55 is configured by connecting two tether base materials 57, 57 in series, as shown in FIGS. 3 to 5.

[0024] The bag body 21 is formed into a bag shape by joining the peripheral edges of a base material (base fabric) of a predetermined shape, and in this embodiment, as shown in Figure 5, it is composed of two peripheral wall panels 60, 63 and two side wall panels 68L, 68R.

[0025] The peripheral wall panel 60 mainly constitutes the area extending from the front end 25a side of the lower wall portion 25 through the upper wall portion 24 to the occupant side wall portion 40, and has a substantially band-like shape with a substantially left-right symmetry in outer shape as shown in FIG. 5. An attachment side portion 61 that constitutes the peripheral area of ​​the inflow opening 30 is disposed on one end side of the peripheral wall panel 60. The peripheral wall panel 63 mainly constitutes the lower wall portion 25, and has a substantially band-like shape with a substantially left-right symmetry in outer shape as shown in FIG. 5. An attachment side portion 64 that constitutes the peripheral area of ​​the inflow opening 30 is also disposed on one end side of the peripheral wall panel 63. The side wall panels 68L, 68R respectively constitute the left wall portion 26 and the right wall portion 27, and have a substantially left-right symmetry in outer shape.

[0026] In the bag body 21 of the embodiment, the recessed shape of the recess 35 is caused by the outer shape of the side wall panels 68L, 68R constituting the left wall portion 26 and the right wall portion 27, more specifically, the shape of the curved portions 70L, 70R constituting part of the outer edges 69L, 69R of the side wall panels 68L, 68R. In the embodiment, as described later, the bag body 21 having the recess 35 can be formed by sewing the outer edges 69L, 69R of the side wall panels 68L, 68R to the edges 60c, 60d, 63c, 63d of the corresponding peripheral wall panels 60, 63.

[0027] Taking the side wall panel 68L constituting the left wall portion 26 as an example, a curved portion 70L (70) like three arcs connected is formed in the front lower end side region of the outer edge 69L (69) of the side wall panel 68L (68) (see FIG. 6). The front arc portion 73 and the rear arc portion 74 arranged on the front and rear sides are configured as approximately arcs that protrude outward (downward or forward), and the central arc portion 75 arranged in the middle is configured as approximately arcs that protrude inward and connect the front arc portion 73 and the rear arc portion 74. In the side wall panel 68, the peripheral region of the front arc portion 73 is near the front lower end of the left wall portion 26 and constitutes the region on the side of the inflow opening 30. In the sidewall panel 68, the area on the rear side portion 74b side of the rear arc portion 74 is near the rear lower end of the left wall portion 26 and constitutes an area near the lower end 40a of the occupant side wall portion 40. In the sidewall panel 68, the peripheral area of ​​the area from the central arc portion 75 to the front side portion 74a of the rear arc portion 74 constitutes an area near the left edge of the recess 35 in the left wall portion 26. In the case of the embodiment, when the sidewall panel 68 is flatly developed, the central arc portion 75 has a central angle α set to about 230° (see FIG. 6). More specifically, in the case of the embodiment, the central arc portion 75 has a radius dimension r set to about 80 mm. In addition, the separation distance D (see FIG. 6) between the front arc portion 73 and the rear arc portion 74 at the closest position is larger than the radius dimension r of the central arc portion 75 and is set to about 125 mm. The front arc portion 73 and the rear arc portion 74 are both set to have a larger radius than the central arc portion 75. Specifically, in the bag body 21 of the embodiment, the outer shapes of the central arc portion 75 and the front region (front region 74a) of the rear arc portion 74 continuing from the central arc portion 75 in the curved portion 70 define the outer shape of the recess 35 at the completion of inflation (the recessed shape of the gap formed between the bag body 21 and the instrument panel 1 at the completion of inflation).

[0028] In the embodiment, the peripheral wall panels 60, 63 and side wall panels 68L, 68R constituting the bag body 21, the front portion material 49 and rear portion 47 constituting the front and rear tethers 45, and the tether base materials 57, 57 constituting the outer tether portion 55 are each formed from flexible woven fabric made of polyester yarn, polyamide yarn, or the like.

[0029] Next, the manufacture of the airbag 20 of the embodiment will be described. One end side of the tether base materials 57, 57 constituting the outer tether portion 55 is sewn to the outer surface side of the peripheral wall panel 63. Also, the rear portion 47 constituting the front and rear tethers 45 is sewn to the inner surface side of the region constituting the occupant side wall portion 40 in the peripheral wall panel 60. First, the mounting side portions 61, 64 formed on the peripheral wall panels 60, 63 are overlapped with each other, and the edge portion 60a of the peripheral wall panel 60 is sewn to the peripheral wall panel 63, and similarly, the edge portion 63a of the peripheral wall panel 63 is sewn to the peripheral wall panel 60. Next, the front portion material 49 constituting the front and rear tethers 45 is overlapped on the mounting side portions 61, 64, and the mounting side portions 61, 64 and the front portion material 49 are sewn to the portion that becomes the periphery of the inflow opening 30. Next, the inflow opening 30 and the mounting hole 31 are opened in the mounting side portions 61, 64. After that, the corresponding edge portions 60b, 63b of the peripheral wall panels 60, 63 are sewn together using a sewing thread. Next, the outer edge 69L of the side wall panel 68L is sewn together with the edge portions 60c, 63c of the peripheral wall panels 60, 63, and similarly, the outer edge 69R of the side wall panel 68R is sewn together with the edge portions 60d, 63d of the peripheral wall panels 60, 63 to form the bag-shaped bag main body 21. The bag main body 21 is turned over using the inflow opening 30, and the front and rear regions 46, 47 are pulled out from the inflow opening 30, and the ends are sewn together to form the front and rear tethers 45, and the ends of the tether base materials 57, 57 are sewn together to form the outer tether portion 55, whereby the airbag 20 can be manufactured.

[0030] Next, the mounting of the airbag device M on the vehicle V will be described. First, the airbag 20 is folded so that it can be stored in the case 16 from a state in which the bolt 13a is protruding from the mounting hole 31 and the retainer 13 is stored inside. In the embodiment, as shown in Figs. 7 to 9, the airbag 20 is stored in the case 16 in a folded folded state 88 after going through a left-right shrinking folding process for shrinking the width dimension on the left-right side from the state of the pre-folded bag 80 after pre-folding, and a front-rear shrinking folding process for shrinking the width dimension on the front-rear side. Specifically, first, while the occupant side wall portion 40 is unfolded substantially flat, the occupant side wall portion 40 is folded with a valley fold in the region of the peripheral wall portion 23 so as to approach the inlet opening 30 side, thereby forming the pre-folded bag 80 as shown in Figs. 7A and 7B. In this pre-folded bag 80, a part of the lower wall portion 25 is woven so as to form a valley fold, and the outer tether portion 55 is arranged in a flat, unfolded state on the lower wall portion 25 (see B in FIG. 7). Next, in the pre-folded bag 80, the left and right edge sides of the inflow opening 30 are folded by roll folding so as to roll toward the occupant side wall portion 40, respectively, to form a left-right reduced folded bag 82 as shown in A and B in FIG. 8. Thereafter, a rear portion 83 of the left-right reduced folded bag 82, which is rearward of the inflow opening 30, is roll folded so as to roll a rear edge 83a toward the peripheral wall portion 23 to form a roll folded portion 86, and the roll folded portion 86 is placed on the inflow opening 30 in an inverted manner (see A and B in FIG. 9). Thereafter, in the left-right shrink-folded bag 82, the front portion 84, which is in front of the inlet opening 30, is folded back so as to be placed on top of the roll-folded portion 86, thereby performing a front-to-back shrink-fold, thereby forming a folded body 88 that can be stored in the case 16, as shown in FIG. 9C.

[0031] The airbag 20 (completely folded body 88) folded in this manner is wrapped around the periphery in a tearable wrapping sheet (not shown) (reference number omitted) so as not to collapse. The completely folded body 88 is then stored in the case 16 with the bolts 13a protruding from the bottom wall portion 16a. The main body 12a of the inflator 12 is then inserted into the case 16 from below the bottom wall portion 16a, and the bolts 13a of the retainer 13 protruding downward from the bottom wall portion 16a are inserted into the flange portion 12c of the inflator 12. Nuts 14 are then fastened to the bolts 13a protruding from the flange portion 12c, whereby the folded airbag 20 and the inflator 12 can be attached to the case 16. Thereafter, the peripheral wall portion 16b of the case 16 is engaged with the connecting wall portion 10c of the airbag cover 10 in the instrument panel 1 mounted on the vehicle V, a bracket (not shown) provided on the case 16 is fixed to the body side of the vehicle V, and the inflator 12 is electrically connected to a control device (not shown), thereby allowing the airbag device M to be mounted on the vehicle V.

[0032] After the airbag device M is mounted on the vehicle V, when inflation gas is discharged from the gas discharge port 12b of the inflator 12, the airbag 20 inflates with the inflation gas flowing into it, pushing open the door portions 10a, 10b of the airbag cover 10. Then, the airbag 20 passes through the opening of the case 16 formed by opening the door portions 10a, 10b of the airbag cover 10, protrudes upward from the case 16, and develops and inflates while protruding toward the rear side of the vehicle, completing the inflation so as to close the gap between the upper surface 2 of the instrument panel 1 and the windshield 7 above the instrument panel, as shown in FIG.

[0033] In the airbag device M of the embodiment, when the airbag 20 is fully inflated, the inflated bag body 21 is disposed in the front lower surface area so as to provide a gap between the airbag 20 and the instrument panel 1, but the rear lower end 21c side of the bag body 21 is connected to the front edge 35a side of the recess 35 constituting this gap via the outer tether portion 55 disposed on the outer peripheral surface side of the bag body 21, and is disposed close to the rear surface 3 of the instrument panel 1 when the airbag 20 is fully inflated. That is, in the airbag device M of the embodiment, the airbag 20 (bag body 21) can be inflated in a partially recessed state so as to provide a gap between the airbag 20 and the instrument panel 1, and therefore the volume can be reduced compared to an airbag not having such a recess. The rear lower end 21c side of the inflated bag body 21 is disposed close to the rear surface 3 of the instrument panel 1 by the outer tether portion 55, and the recess 35 formed in the bag body 21 is formed in an area forward of the occupant side wall portion 40 that protects the occupant when inflation is complete, so that even in the configuration with the recess 35, the area on the rear lower end 21c side of the bag body 21 can be supported by the instrument panel 1, and the occupant moving forward can be stably received by the occupant side wall portion 40. As a result, in the airbag device M of the embodiment, even if the interior shape of the vehicle to be mounted is different, by appropriately setting the shape of the recess 35 formed in the bag body 21, it is possible to suppress an increase in the volume of the airbag 20 and also suppress an increase in the size of the device itself.

[0034] Therefore, the airbag device M of the embodiment can be made compact in configuration and can adequately protect the occupant.

[0035] The airbag device M of the embodiment is mounted on a vehicle V in which the monitor 5 as a protruding part is disposed so as to partially protrude upward from the instrument panel 1, and the monitor 5 is disposed behind the mounting area of ​​the airbag device M. However, since the bag body 21 is configured to be inflatable so that the monitor 5 disposed so as to partially protrude upward from the instrument panel 1 is positioned within the recess 35, even in such a configuration in which the airbag device M is mounted on the vehicle V, it is possible to prevent the inflating bag body 21 from significantly interfering with the monitor 5 as a protruding part, and it is possible to smoothly complete the inflation. To explain in detail the deployment behavior of the airbag 20 (bag body 21) in the airbag device M of the embodiment, when the bag body 21 inflates while the inflation gas flows therein, it first protrudes upward from the case 16, and then unfolds while the roll-folded part 86 protrudes rearward. As shown in A and B of FIG. 10, the roll-folded portion 86 protrudes rearward so as to climb over the monitor 5, and then is widely deployed up and down so as to unfold. At this time, the bag body 21 inflates so as to bypass the monitor 5 by the recess 35 (so as to cause the monitor 5 to enter the recess 35) and to widely deploy the occupant side wall portion 40 up and down at a position behind the monitor 5 (see A of FIG. 11). In addition, since the lower end 40a side of the occupant side wall portion 40 (the rear lower end 21c side when the bag body 21 is fully inflated) is connected by the outer tether portion 55 to the region on the front edge 35a side of the recess 35 (the portion located near the upper end 5b of the monitor 5), the occupant side wall portion 40 is prevented from protruding excessively downward and rearward. That is, the bag body 21 is prevented from protruding significantly downward and rearward during deployment and inflation by the outer tether portion 55, and thus is inflated while being restricted from swinging significantly in the vertical direction. The occupant side wall portion 40 is prevented from swinging in the vertical direction, and while maintaining a state where it is widely deployed in the vertical direction, it is deployed toward the rear (see A and B in FIG. 11). Therefore, the bag body 21 is inflated in a state where large swinging in the vertical direction is prevented, and the occupant side wall portion 40 can quickly cover the rear of the monitor 5.When the bag body 21 is fully inflated, as shown in FIG. 12, the outer tether portion 55 is positioned close to the rear surface 5a of the monitor 5. Therefore, when the occupant is received by the occupant side wall portion 40, the outer tether portion 55 is supported by the monitor 5, thereby ensuring a reaction force and providing adequate protection for the occupant.

[0036] In the airbag device M of the embodiment, as described above, the outer shape of the recess 35 of the bag body 21 is determined by the shape of the curved portion 70 (70L, 70R) provided on the side wall panel 68 (68L, 68R). In the embodiment, the curved portion 70 is arranged so as to connect three arcs when the side wall panel 68 is flatly developed. In the curved portion 70, the central arc portion 75 arranged in the middle constitutes the most recessed area of ​​the recess 35, and the central arc portion 75 is formed in a substantially arc shape with a radius dimension r of about 80 mm and a central angle α of about 230°, and is formed in a shape that is gently curved and greatly recessed. The area from the central arc portion 75 to the front area (front portion 74a) of the rear arc portion 74 is formed in an S-shaped curve. In addition, in the curved portion 70, the distance D between the front arc portion 73 and the rear arc portion 74 at the closest position is set to about 125 mm, which is larger than the radius dimension r of the central arc portion 75. That is, the recess 35 defined in the outer shape of the curved portion 70 in the side wall panel 68 is formed so that the lower end side opens widely in the front and rear directions and is greatly recessed upward while maintaining a wide state in the front and rear directions when the bag body 21 is fully inflated. Therefore, if the bag body is configured not to have an outer tether portion, the bag body will unfold so as to bypass the monitor due to the recess, but since the recess is formed so that the lower end side (the lower surface side of the bag body) opens widely in the front and rear directions, the portion of the bag body located behind the recess (the lower end side area of ​​the occupant side wall portion) will be in a state where it protrudes greatly backward. Incidentally, if the outer tether portion is not provided, the bag body will deploy in a manner that extends the area that curves in an approximately S-shape from the rear of the central arc portion that forms the periphery of the recess to the front of the rear arc portion, and the rear lower end side of the bag body, i.e., the area at the lower end of the occupant side wall portion, will deploy in a manner that protrudes rearward and downward more than necessary.In the airbag device M of the embodiment, the outer tether portion 55 is arranged on the bag body 21. Therefore, even in a configuration having a recess 35 that is wide open in the front and rear directions and that is deeply recessed upward, when the bag body 21 is deployed and inflated, the area on the rear lower end 21c side of the bag body 21 (the area on the lower end 40a side of the occupant side wall portion 40) can be appropriately prevented from protruding significantly downward and rearward.

[0037] In the airbag device M of the embodiment, the outer tether portion 55, which regulates the shape of the bag body 21 at the completion of inflation, is set so that the length dimension L1 is substantially the same as the length dimension L2 of the straight line connecting the points P1 and P2 corresponding to the intended connection portions 77F and 77B that will respectively connect both ends of the outer tether portion 55 when the side wall panel 68 is flatly deployed. That is, in the embodiment, the outer tether portion 55 can regulate the behavior (excessive protrusion downward toward the rear) of the area on the rear lower end 21c side of the bag body 21 during inflation, but is not configured to excessively pull the area on the rear lower end 21c side of the bag body 21 excessively forward when the airbag 20 is completed in inflation. Therefore, it is possible to suppress deformation of the bag body 21 at the completion of inflation due to excessive pulling by the outer tether portion 55, and the bag body 21 that has completed inflation can stably protect the occupant.

[0038] Incidentally, even if such a curved portion is not provided, it is possible to form a recess by providing, for example, a curved portion that is bent at an acute angle, instead of a curved portion, at a similar position on the side wall panel, but considering the manufacturing cost of the bag body (ease and speed of sewing the side wall panel and the peripheral panel), it is preferable to provide a curved portion that is gently curved as in the embodiment, rather than a curved portion that is bent at an acute angle. In other words, the airbag used in the airbag device of the embodiment allows easy sewing of the bag body, can suppress increases in manufacturing labor and costs, and can adequately protect the occupant when inflation is complete, even if the airbag is installed in a vehicle in which a monitor that partially protrudes between the airbag and the occupant is provided.

[0039] In the airbag 20 of the embodiment, the outer tether portion 55 is configured to be a single wide band having a width dimension set to be approximately equal to the width dimension of the lower wall portion 25 of the bag body 21, but the outer shape and number of the outer tether portions are not limited to those of the embodiment. For example, the outer tether portion may be configured to be a narrow band or a multiple number of string-like members arranged side by side on the left and right sides.

[0040] In the embodiment, the passenger seat airbag device disposed in front of the passenger seat has been described as an example, but the present invention is not limited to the passenger seat airbag device. For example, the present invention may be applied to a driver's seat airbag device that is mounted in a position in front of the steering wheel on the instrument panel and includes an airbag that inflates to cover the rear surface of the steering wheel. When applied to a driver's seat airbag device having such a configuration, even if the steering wheel is disposed so as to partially protrude upward from the instrument panel, the rear side of the steering wheel as a protruding object can be smoothly covered by the airbag that has completed inflation, and the driver can be appropriately protected. [Explanation of symbols]

[0041] 1...instrument panel, 2...upper surface, 3...rear surface, 5...monitor (protrusion), 10...airbag cover, 12...inflator, 16...case (storage area), 20...airbag, 21...bag body, 21c...rear lower end, 35...recess, 35a...front edge, 40...occupant side wall portion, 55...outer tether portion, MP...occupant, V...vehicle, M...passenger seat airbag device (airbag device).

Claims

1. The device is configured to include an airbag that is disposed on an upper surface side of an instrument panel and can be inflated by flowing inflation gas therein, an inflator that supplies inflation gas to the airbag, and a storage portion that stores the folded airbag and the inflator, In an airbag device configured such that, when the airbag is inflated by the inflation gas discharged from the inflator flowing into the airbag, the airbag protrudes upward from the storage portion and deploys rearward, The airbag is configured to include a bag body that is inflated by flowing inflation gas therein, and an outer tether portion that is disposed on an outer peripheral surface side of the bag body and that regulates the shape of the bag body when it is fully inflated, the bag body is configured to have an occupant side wall portion capable of protecting an occupant seated in the front seat disposed on a rear side thereof when the bag body is fully inflated, and to have a recess portion recessed upwardly on a lower surface side of a region forward of the occupant side wall portion when the bag body is fully inflated so as to provide a gap between the bag body and the instrument panel, an outer tether portion configured to connect a lower rear end side of the bag body and a front edge side of the recess when inflation is complete, and to enable the lower rear end of the bag body to be positioned close to the rear surface of the instrument panel when inflation is complete.

2. the bag body is configured to inflate so as to position a protrusion, which is disposed so as to protrude partially upward from the instrument panel, within the recess; 2. The airbag device according to claim 1, wherein the outer tether portion is disposed adjacent to a rear surface side of the protrusion when the bag body is fully inflated.

Images