Airbag system
The airbag system with a recessed design and outer tether ensures compactness and effective protection by stabilizing deployment and reducing interference, addressing the volume and cost issues of conventional systems.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- TOYODA GOSEI CO LTD
- Filing Date
- 2023-09-26
- Publication Date
- 2026-06-18
Smart Images
Figure 0007875468000001 
Figure 0007875468000002 
Figure 0007875468000003
Abstract
Description
Technical Field
[0001] The present invention relates to an airbag device having a configuration including an airbag disposed on the upper surface side of an instrument panel and inflatable by allowing inflation gas to flow therein, an inflator for supplying the inflation gas to the airbag, and a storage portion for storing the folded airbag and the inflator.
Background Art
[0002] Conventionally, as an airbag device having such a configuration, there is one disposed in front of the passenger seat in order to protect a passenger seated in the passenger seat. In an airbag device for a passenger seat having such a configuration, when the inflator operates, the airbag folded and stored in the storage portion expands 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). Specifically, the inflated airbag is configured to support the front side by an instrument panel or a windshield disposed above the instrument panel and receive and protect a forward-moving passenger.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] However, when such an airbag device is mounted on a vehicle of a type in which an instrument panel is disposed at a position significantly separated forward from the front seat where a passenger is seated, the distance from the mounting position of the airbag device to the passenger is large. Therefore, in order to stably receive the passenger, the volume of the airbag becomes large, leading to an increase in the size of the device and the manufacturing cost.
[0005] The present invention aims to solve the above-mentioned problems and to provide an airbag system that can be configured compactly and effectively protect occupants. [Means for solving the problem]
[0006] The airbag device according to the present invention is configured to include an airbag positioned on the upper side of the instrument panel and capable of being inflated by the inflow of inflation gas, an inflator that supplies inflation gas to the airbag, and a storage area for storing the folded airbag and inflator. In an airbag system configured such that when an airbag inflates by allowing inflation gas discharged from an inflator to flow into its interior, it protrudes upward from its storage location while simultaneously deploying backward, The airbag is configured to include a bag body into which inflation gas is introduced to inflate, and an outer tether portion positioned on the outer surface of the bag body to regulate the shape of the bag body once it has been fully inflated. The bag body is configured such that, when fully inflated, it has a passenger side wall on the rear side capable of protecting occupants seated in the front seats, and on the lower side of the area in front of the passenger side wall when fully inflated, it has a recess that curves upward to create a gap between it and the instrument panel. The outer tether is positioned to connect the rear lower end of the bag body when inflation is complete with the front edge of the recess, and is configured to allow the rear lower end of the bag body when inflation is complete to be positioned close to the rear surface of the instrument panel.
[0007] In the airbag device of the present invention, when the airbag inflation is complete, the inflated bag body is positioned in the front lower surface area such that a gap is created between it and the instrument panel. The rear lower end of the bag body is connected to the front edge of the recess that constitutes this gap via an outer tether portion located on the outer peripheral surface of the bag body, and when inflation is complete, it is positioned close to the rear surface of the instrument panel. In other words, in the airbag device of the present invention, the airbag (bag body) can be inflated in a partially recessed state so as to create a gap between it and the instrument panel, thus reducing the volume compared to an airbag with a configuration that does not have such a recess. Furthermore, the rear lower end of the inflated bag body is positioned close to the rear surface of the instrument panel by the outer tether, and the recess formed in the bag body is formed in a region in front of the occupant side wall portion that protects the occupant when inflation is complete. As a result, even with a configuration that includes a recess, the rear lower end of the bag body can be supported by the instrument panel, and the occupant moving forward can be stably caught by the occupant side wall portion. Consequently, with the airbag device of the present invention, even if the interior shape of the vehicle in which it is installed differs, the volume of the airbag can be suppressed to increase by appropriately setting the shape of the recess formed in the bag body, and the size of the device itself can also be suppressed.
[0008] Therefore, the airbag system of the present invention can have a compact configuration and can effectively protect occupants.
[0009] Furthermore, in the airbag device of the present invention, the bag body is inflated in such a way that a protrusion, which is positioned to partially protrude upward from the instrument panel, is located within a recess. It is preferable to configure the outer tether portion to be positioned close to the rear side of the protrusion when the bag body has finished inflating.
[0010] With this configuration, even when the airbag system is installed in a vehicle with a protruding part extending from the instrument panel, the recessed area prevents the inflating bag body from significantly interfering with the protrusion, allowing for smooth inflation. Furthermore, in the airbag system with the above configuration, the outer tether is positioned close to the rear side of the protrusion when the bag body has finished inflating. This allows the outer tether to be supported by the protrusion when the occupant is caught by the occupant side wall, thereby ensuring a reaction force and effectively protecting the occupant. [Brief explanation of the drawing]
[0011] [Figure 1] This is a schematic perspective view showing the instrument panel of a vehicle equipped with a passenger-side airbag system, which is one embodiment of the present invention. [Figure 2] This is a schematic longitudinal cross-sectional view showing the passenger-side airbag system of the embodiment installed in a vehicle. [Figure 3] This is a schematic perspective view showing the airbag used in the passenger-side airbag system of the embodiment in an inflated state. [Figure 4] Figure 3 is a schematic longitudinal cross-section of the airbag in the front-to-back direction. [Figure 5] Figure 3 is a plan view showing the base materials that make up the airbag arranged in a grid. [Figure 6] Figure 3 is an enlarged plan view of the side wall panel that makes up the airbag. [Figure 7] Figure 3 shows a plan view and a bottom view of the pre-folded bag formed by folding the airbag. [Figure 8] Figure 3 is a schematic diagram showing the folding process of the airbag. [Figure 9] Figure 3 is a schematic diagram showing the airbag folding process, and it shows the process after Figure 8. [Figure 10] This is a schematic longitudinal cross-sectional view showing the inflation process of the airbag in the passenger-side airbag device of the embodiment. [Figure 11]This is a schematic longitudinal cross-sectional view showing the inflation process of the airbag in the passenger-side airbag system of the embodiment, and shows the process after Figure 10. [Figure 12] This is a schematic longitudinal cross-sectional view showing the completed inflation state of the passenger-side airbag device according to the embodiment. [Figure 13] This is a schematic rear view of the passenger-side airbag system of the embodiment, showing the airbag in its fully inflated state as seen from the rear of the vehicle. [Modes for carrying out the invention]
[0012] Hereinafter, one embodiment of the present invention will be described with reference to the drawings. In this embodiment, a passenger-side airbag device (hereinafter abbreviated as "airbag device") M, which is positioned in front of the passenger seat as a front seat, will be used as an example for the explanation. As shown in Figures 1 and 2, the airbag device M is a top-mount type positioned on the upper surface 2 side of the instrument panel (hereinafter abbreviated as "instrument panel") 1. In this embodiment, as shown in Figures 1 and 2, a monitor 5 is provided as a protruding object on the rear side of the rear of the area where the airbag device M is positioned, so as to protrude partially upward. In detail, in this embodiment, the instrument panel 1 is configured to tilt its rear surface 3 slightly forward with respect to the vertical direction, and the monitor 5 is also positioned so as to be slightly tilted forward with respect to the vertical direction, substantially along the rear surface 3 of the instrument panel 1 (see Figure 2). Furthermore, in this embodiment, the monitor 5 is formed to be slightly wider from left to right than the airbag device M (more specifically, the airbag cover 10, which will be described later) (see Figure 1), and is positioned directly facing the occupant MP seated in the passenger seat (see Figure 13). In this embodiment, unless otherwise specified, the front-rear, up-down, and left-right directions correspond to the front-rear, up-down, and left-right directions of the vehicle V.
[0013] As shown in FIGS. 2 and 12, the airbag device M includes a folded airbag 20, an inflater 12 that supplies inflation gas to the airbag 20, a case 16 as a storage part for storing the folded airbag 20 and the inflater 12, a retainer 13 for attaching the airbag 20 and the inflater 12 to the case 16, and an airbag cover 10 that covers the folded airbag 20.
[0014] In the case of the embodiment, the airbag cover 10 is integrally formed with the instrument panel 1 made of synthetic resin, and is configured such that when the airbag 20 is deployed and inflated, the front and rear door portions 10a and 10b are pushed open by the airbag 20. Further, a connecting wall portion 10c connected to the case 16 is formed around the door portions 10a and 10b of the airbag cover 10.
[0015] As shown in FIG. 2, the inflater 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 inflater 12 to the case 16.
[0016] The case 16 as a storage part is formed in a substantially rectangular parallelepiped shape made of sheet metal having a rectangular opening on the upper end side. As shown in FIG. 2, it includes a substantially rectangular plate-shaped bottom wall portion 16a into which the inflater 12 is inserted and attached from below, and a peripheral wall portion 16b that extends upward from the outer peripheral edge of the bottom wall portion 16a and locks the connecting wall portion 10c of the airbag cover 10. In the case of the embodiment, the airbag 20 and the inflater 12 are attached to the bottom wall portion 16a of the case 16 by passing each bolt 13a of the retainer 13 disposed in the airbag 20 through the periphery of an inflow opening 30 (to be described later) in the airbag 20, the bottom wall portion 16a of the case 16, and the flange portion 12c of the inflater 12 and tightening nuts 14. Further, a bracket (not shown) 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 includes a bag body 21 that inflates by introducing inflation gas into it, front and rear tethers 45 that are positioned inside the bag body 21 to regulate the completed inflation shape of the bag body 21, and an outer tether portion 55 that is positioned on the outer circumferential surface side of the bag body 21 to regulate the completed inflation shape of the bag body 21.
[0018] As shown in Figure 12, the bag body 21 is configured to be positioned to close the gap between the upper surface 2 of the instrument panel 1 and the windshield 7 above the instrument panel 1 when inflation is complete. Specifically, as shown in Figures 3 and 4, the bag body 21 has an outer shape when inflation is complete that is roughly a square pyramidal shape with the top facing the front end, and the bottom side is significantly recessed upwards. The bag body 21 includes an occupant side wall portion 40 positioned on the rear side (rear surface side) which becomes the occupant MP side when inflation is complete, 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 which is attached to the case 16 side.
[0019] The peripheral wall portion 23 is positioned to primarily block the space 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) has finished inflating. It comprises an upper wall portion 24 and a lower wall portion 25 that are positioned opposite each other in the vertical direction, and a left wall portion 26 and a right wall portion 27 that are positioned opposite each other in the horizontal direction when inflation is complete. Near the front end 25a of the lower wall portion 25, at a position approximately in the center from left to right, an inlet opening 30 is formed, which is approximately circular in shape to allow inflation gas to flow into the interior, and whose periphery is attached to the bottom wall portion 16a of the case 16. Multiple (four in this embodiment) mounting holes 31 are formed on the periphery of the inlet opening 30 for inserting the bolts 13a of the retainer 13 to attach the periphery of the inlet opening 30 to the bottom wall portion 16a of the case 16. The left wall 26 and the right wall 27 have vent holes 33 formed in a roughly circular shape to exhaust excess expansion gas that has flowed into the bag body 21. Each vent hole 33 is positioned in the left wall 26 and the right wall 27 at a location above and behind the area where the recess 35 (described later) is located.
[0020] Furthermore, in the bag body 21 of this embodiment, the lower wall portion 25 is configured to be curved when viewed from the left-right direction, such that the intermediate portion between the front and rear is positioned upwards. This curved shape is provided over substantially the entire area on both the left and right sides (i.e., substantially the entire area on both the left and right sides of the bag body 21) (see Figures 3 and 4). In this embodiment, due to the curved shape of the lower wall portion 25, the bag body 21 has a recess 35 on the lower surface area that is recessed upwards. More specifically, the recess 35 is formed at a position that is substantially in the center front to back when the bag body 21 is viewed from the left and right sides when it is fully inflated. In other words, it is formed on the lower surface area in front of the occupant side wall portion 40, separated front to back from the occupant side wall portion 40 located on the rear side of the bag body 21. As described above, the recess 35 is formed continuously over substantially the entire area on both the left and right sides of the bag body 21 so that the recess shape is the same. In other words, by providing this recess 35, the bag body 21 will have a gap extending across the entire left and right sides between it and the instrument panel 1 when inflation is complete. Furthermore, when the airbag 20 is fully inflated, this recess 35 will be positioned to correspond to the monitor 5 that protrudes upward on the rear surface 3 of the instrument panel 1 (see Figure 12). In other words, when inflation is complete, the bag body 21 will be positioned so as to bypass the monitor 5 by the recess 35.
[0021] The occupant side wall portion 40 is positioned at the rear end 21b of the bag body 21, behind the monitor 5, when the bag body 21 is fully inflated, and is arranged substantially along the vertical direction so as to face the occupant MP seated in the passenger seat (see Figure 12). Specifically, as shown in Figure 13, the occupant side wall portion 40 is configured to have a substantially rectangular shape with a wide vertical dimension when fully inflated, so as to be able to broadly cover the front of the upper body of the occupant MP. In this embodiment, the lower end 40a of the occupant side wall portion 40 is positioned below the monitor 5 when fully inflated, and the width dimension in the left-right direction is set to be larger than the width dimension in the left-right direction of the monitor 5, so as to cover the entire rear side of the monitor 5 (see Figures 12 and 13). Also, in this embodiment, when the bag body 21 is fully inflated, the upper side (upper wall portion 24 side) comes into contact with the windshield 7.
[0022] The front and rear tethers 45, which act as internal tethers to regulate the completed inflation shape of the bag body 21, are arranged to connect the approximate center of the left and right sides of the occupant side wall portion 40 with the front end 21a side of the bag body 21. These front and rear tethers 45 are arranged to regulate excessive rearward protrusion of the occupant side wall portion 40 in the initial stages of inflation, and to regulate the position of the occupant side wall portion 40 (the distance from the periphery of the inflow opening 30) when inflation is complete. In this embodiment, the front and rear tethers 45 are configured to connect a front portion 46 extending from the periphery of the inflow opening 30 with a rear portion 47 extending from the occupant side wall portion 40 (see Figures 3 and 4). In this embodiment, the front portion 46 is configured by partially folding a strip-shaped material 49 for the front portion shown in Figure 5. The rear portion 47 has a roughly trapezoidal shape, narrowing towards the front end where it connects to the front portion 46. The rear portion 47 is sewn to the occupant side wall portion 40 at a position approximately in the center of the left and right sides, with its trailing edge aligned in the vertical direction.
[0023] The outer tether portion 55 regulates the completed inflation shape of the bag body 21. It is positioned on the outer circumferential surface of the bag body 21 so as to connect the rear lower end 21c side of the bag body 21 when inflation is complete (specifically, near the rear end 25b of the lower wall portion 25) and the front edge 35a side of the recess 35 (the area behind the inflow opening 30). In this embodiment, when the airbag 20 (bag body 21) is inflated on its own, the outer tether portion 55 is positioned so as to cross the recess 35, as shown in Figure 4. When inflation is complete in the vehicle-mounted state, it is positioned close to the rear surface 5a of the monitor 5, as shown in Figure 12. The outer tether portion 55 is designed to prevent 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) from protruding excessively downward and rearward when the bag body 21 is deployed and inflated, and to allow the rear lower end 21c side of the bag body 21 to be positioned close to the rear surface 3 of the instrument panel 1 when the bag body 21 has finished inflating. More specifically, the upper end 55a (one end) of the outer tether portion 55 is connected to the front edge 35a side of the recess 35 when the bag body 21 has finished inflating and is mounted on the vehicle (see Figure 12). The other end (lower end 55b) of the outer tether portion 55 is connected to a position near the rear edge 35b of the recess 35, above the lower edge 21d of the bag body 21 when inflation is complete (near the rear end 25b of the lower wall portion 25) (see Figure 4). More specifically, the lower end 55b of the outer tether portion 55 is connected to a position in the bag body 21 when it is fully inflated and mounted on the vehicle, as shown in Figure 12, below the monitor 5 and close to the rear surface 3 of the instrument panel 1. The length dimension L1 (see Figure 4) of the outer tether portion 55 is set to be approximately the same as the length dimension L2 (see Figure 5) of the straight line connecting points P1 and P2, which correspond to the planned connecting parts 77F and 77B (see Figure 5) that will connect both ends (upper end 55a and lower end 55b) of the outer tether portion 55, when the side wall panels 68 (68L and 68R) that make up the bag body 21 are laid flat.Furthermore, the outer tether section 55 is configured to have a width dimension approximately equal to that of the lower wall section 25, and more specifically, to be slightly smaller than the width dimension of the lower wall section 25 (the width dimension of the peripheral wall panel 63, which will be described later) (see Figure 5). As described above, the outer tether section 55 is configured so that when the bag body 21 is fully inflated during vehicle mounting, its lower end 55b is positioned below the monitor 5, and when the bag body 21 is fully inflated, it widely covers almost the entire rear surface 5a of the monitor 5 in all directions. In this embodiment, the outer tether section 55 is configured by connecting two tether base materials 57, 57 in series, as shown in Figures 3 to 5.
[0024] The bag body 21 is constructed in a bag shape by joining the periphery edges of a base material (base fabric) of a predetermined shape. In this embodiment, as shown in Figure 5, it is composed of two peripheral wall panels 60 and 63 and two side wall panels 68L and 68R.
[0025] The peripheral wall panel 60 mainly constitutes the area from the front end 25a side of the lower wall section 25, through the upper wall section 24, to the occupant side wall section 40, and as shown in Figure 5, its external shape is roughly symmetrical and roughly strip-shaped. An attachment side section 61 that constitutes the area around the inlet opening 30 is provided on one end of the peripheral wall panel 60. The peripheral wall panel 63 mainly constitutes the lower wall section 25, and as shown in Figure 5, its external shape is roughly symmetrical and roughly strip-shaped. An attachment side section 64 that constitutes the area around the inlet opening 30 is also provided on one end of this peripheral wall panel 63. The side wall panels 68L and 68R constitute the left wall section 26 and the right wall section 27, respectively, and their external shapes are roughly symmetrical.
[0026] In the bag body 21 of this embodiment, the recess shape of the recess 35 is due to the external shape of the side wall panels 68L and 68R that constitute the left wall portion 26 and the right wall portion 27, and more specifically, to the shape of the curved portions 70L and 70R that constitute part of the outer edges 69L and 69R of the side wall panels 68L and 68R. In this embodiment, as will be described later, the bag body 21 having the recess 35 can be formed by sewing the outer edges 69L and 69R of each side wall panel 68L and 68R to the edges 60c, 60d, 63c, and 63d of the corresponding peripheral wall panels 60 and 63.
[0027] Taking the side wall panel 68L that constitutes the left wall section 26 as an example, to explain in detail, a curved section 70L(70) is formed in the area on the front lower end side of the outer edge 69L(69) of the side wall panel 68L(68), which is like three arcs connected together (see Figure 6). The front arc section 73 and the rear arc section 74, which are located on the front and rear sides, are configured as roughly arc-shaped protrusions toward the outward (downward or forward) and the central arc section 75, located in the middle, is configured as a roughly arc-shaped protrusion toward the inward, connecting the front arc section 73 and the rear arc section 74. In the side wall panel 68, the peripheral area of the front arc section 73 is near the front lower end of the left wall section 26 and constitutes the area to the side of the inflow opening 30. In the side wall panel 68, the area on the rear portion 74b side of the rear arc portion 74 is near the rear lower end of the left wall portion 26 and constitutes the area near the lower end 40a of the occupant side wall portion 40. Furthermore, in the side wall panel 68, the peripheral area of the portion from the central arc portion 75 to the front portion 74a of the rear arc portion 74 constitutes the area near the left edge of the recess 35 in the left wall portion 26. In this embodiment, when the side wall panel 68 is laid flat, the central arc portion 75 is set to a central angle α of approximately 230° (see Figure 6). More specifically, in this embodiment, the radius dimension r of the central arc portion 75 is set to approximately 80 mm. Also, the separation distance D (see Figure 6) at the closest position between the front arc portion 73 and the rear arc portion 74 is larger than the radius dimension r of the central arc portion 75 and is set to approximately 125 mm. Both the front arc portion 73 and the rear arc portion 74 have a radius dimension that is larger than that of the central arc portion 75. Specifically, in the bag body 21 of this embodiment, the outer shape of the central arc portion 75 and the front region (front portion 74a) of the rear arc portion 74 that extends from the central arc portion 75 in the curved portion 70 defines the outer shape of the recess 35 when inflation is complete (the recessed shape of the gap formed between the bag body 21 and the instrument panel 1 when inflation is complete).
[0028] In this embodiment, the peripheral wall panels 60, 63 and side wall panels 68L, 68R that constitute the bag body 21, the front part material 49 and rear part 47 that constitute the front and rear tethers 45, and the tether base materials 57, 57 that constitute the outer tether portion 55 are each formed from a flexible woven fabric made of polyester yarn, polyamide yarn, or the like.
[0029] Next, the manufacturing of the airbag 20 according to the embodiment will be described. One end of each tether base material 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 of the peripheral wall panel 60. First, the mounting side portions 61, 64 formed on the peripheral wall panels 60, 63 are overlapped, 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 material 49 for the front portion constituting the front and rear tethers 45 is overlapped with these mounting side portions 61, 64, and the mounting side portions 61, 64 and the material 49 for the front portion are sewn together at the periphery of the inlet opening 30. Next, an inlet opening 30 and a mounting hole 31 are made in the mounting side portions 61 and 64. Then, the corresponding edges 60b and 63b of the peripheral wall panels 60 and 63 are sewn together using suture thread. Next, the outer edge 69L of the side wall panel 68L is sewn to the edges 60c and 63c of the peripheral wall panels 60 and 63, and similarly, the outer edge 69R of the side wall panel 68R is sewn to the edges 60d and 63d of the peripheral wall panels 60 and 63 to form a bag-shaped body 21. The bag body 21 is then inverted using the inlet opening 30, and the front portion 46 and the rear portion 47 are pulled out from the inlet opening 30 and their ends are sewn together to form the front and rear tethers 45. The ends of the tether base materials 57 and 57 are then sewn together to form the outer tether portion 55, thereby manufacturing the airbag 20.
[0030] Next, the installation of the airbag device M into the vehicle V will be explained. First, the airbag 20 is folded so that it can be stored in the case 16, starting from a state in which the retainer 13 is housed inside with the bolt 13a protruding from the mounting hole 31. In this embodiment, as shown in Figures 7 to 9, the airbag 20 is stored in the case 16 in the state of a folded complete body 88, after undergoing a left-right reduction folding process to reduce the width dimension on the left-right side and a front-rear reduction folding process to reduce the width dimension on the front-rear side, starting from the state of a pre-folded bag 80 after pre-folding. Specifically, first, the occupant side wall portion 40 is unfolded to be approximately flat, and the occupant side wall portion 40 is brought closer to the intake opening 30 side, and a valley fold is made in the area of the peripheral wall portion 23, forming a pre-folded bag 80 as shown in Figures 7A and 7B. In this spare folding bag 80, the lower wall portion 25 is partially folded in so that a valley fold is made, and the outer tether portion 55 is positioned flat on the lower wall portion 25 (see Figure 7B). Next, in the spare folding bag 80, the left and right edges of the inlet opening 30 are folded by a roll fold so that they are rolled towards the occupant side wall portion 40, respectively, to form the left and right reduced folding bags 82 as shown in Figures 8A and 8B. After that, the rear portion 83 of the left and right reduced folding bags 82, which is behind the inlet opening 30, is roll-folded so that the rear edge 83a is rolled towards the peripheral wall portion 23, forming a roll-folded portion 86, and this roll-folded portion 86 is inverted and placed on top of the inlet opening 30 (see Figures 9A and 9B). Subsequently, in the left and right retractable bag 82, the front portion 84, which is in front of the inflow opening 30, is folded back so that it is placed on top of the roll-fold portion 86, and by performing front-to-back retractable folding, a completed folded body 88 that can be stored in the case 16 can be formed, as shown in Figure 9C.
[0031] The folded airbag 20 (folded body 88) is then wrapped around the perimeter with a tearable wrapping sheet (not shown, no symbols shown) to prevent it from unraveling. The folded body 88 is then stored inside the case 16 with the bolts 13a protruding from the bottom wall portion 16a. The main body portion 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 through the flange portion 12c of the inflator 12. Nuts 14 are then fastened to each bolt 13a protruding from the flange portion 12c, thereby attaching the folded airbag 20 and inflator 12 to the case 16. Subsequently, the peripheral wall portion 16b of the case 16 is locked to the connecting wall portion 10c of the airbag cover 10 on 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 enabling the airbag device M to be mounted on the vehicle V.
[0032] After the airbag device M is installed in the vehicle V, when inflation gas is discharged from the gas outlet 12b of the inflator 12, the airbag 20 inflates by allowing the inflation gas to flow into it, pushing open the door portions 10a and 10b of the airbag cover 10. The airbag 20 then expands and inflates, protruding upward from the case 16 through the opening of the case 16 formed by opening the door portions 10a and 10b of the airbag cover 10, and also protruding toward the rear of the vehicle, until it completes its inflation by sealing the space between the upper surface 2 of the instrument panel 1 and the windshield 7 above the instrument panel, as shown in Figure 12.
[0033] In the airbag device M of this embodiment, when the airbag 20 has finished inflating, the inflated bag body 21 is positioned in the front lower surface area so as to create a gap between it and the instrument panel 1. The rear lower end 21c of the bag body 21 is connected to the front edge 35a of the recess 35 that constitutes this gap via an outer tether portion 55 located on the outer peripheral surface of the bag body 21, so that when inflation is complete, it is positioned close to the rear surface 3 of the instrument panel 1. In other words, in the airbag device M of this embodiment, the airbag 20 (bag body 21) can be inflated in a partially recessed state so as to create a gap between it and the instrument panel 1, thus reducing the volume compared to an airbag that does not have such a recess. Furthermore, the rear lower end 21c side of the inflated bag body 21 is positioned 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 a region that is in front of the occupant side wall portion 40 that protects the occupant when inflation is complete. As a result, even with a configuration that includes a 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 caught by the occupant side wall portion 40. Consequently, in the airbag device M of this embodiment, even if the interior shape of the vehicle on which it is installed differs, the volume of the airbag 20 can be suppressed to increase by appropriately setting the shape of the recess 35 formed in the bag body 21, and the size of the device itself can also be suppressed.
[0034] Therefore, the airbag device M of this embodiment can have a compact configuration and can effectively protect the occupants.
[0035] Furthermore, the airbag device M of this embodiment is mounted on a vehicle V in which the monitor 5, as a protruding part, is positioned to partially protrude upward from the instrument panel 1, and the monitor 5 is positioned behind the mounting area of the airbag device M. However, since the bag body 21 is configured to be inflatable so as to position the monitor 5, which is positioned to partially protrude upward from the instrument panel 1, within the recess 35, even when mounted on such a vehicle V, it is possible to suppress significant interference between the inflating bag body 21 and the monitor 5 as a protruding part, and to complete inflation smoothly. To describe in detail the deployment behavior of the airbag 20 (bag body 21) in the airbag device M of this embodiment, when the bag body 21 inflates while inflation gas flows into it, it first protrudes upward from the case 16, and then deploys by unfolding the rolled fold portion 86 so as to protrude backward. As shown in Figures 10A and 10B, the rolled-up portion 86 protrudes backward over the monitor 5, and then expands widely vertically to eliminate the fold. At this time, the bag body 21 expands so that it bypasses the monitor 5 via the recess 35 (allowing the monitor 5 to enter the recess 35), and at a position behind the monitor 5, the occupant side wall portion 40 expands widely vertically (see Figure 11A). Furthermore, since the lower end 40a side of the occupant side wall portion 40 (the rear lower end 21c side when the bag body 21 has finished expanding) is connected by the outer tether portion 55 to the area 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 far downward and rearward. In other words, the bag body 21 is prevented from protruding far downward and rearward by the outer tether portion 55 when it expands, and therefore expands with restricted large vertical swinging. The occupant side wall portion 40 is then suppressed from swinging in the vertical direction and expands towards the rear while maintaining a wide, vertically deployed state (see Figure 11 A and B). As a result, the bag body 21 expands while suppressing large swings in the vertical direction, and the occupant side wall portion 40 can quickly cover the rear of the monitor 5.Furthermore, when the bag body 21 is fully inflated, as shown in Figure 12, the outer tether portion 55 is positioned close to the rear surface 5a of the monitor 5. This allows the outer tether portion 55 to be supported by the monitor 5 when the occupant is received by the occupant side wall portion 40, thereby ensuring a reaction force and effectively protecting the occupant.
[0036] In the airbag device M of this embodiment, as described above, the external shape of the recess 35 of the bag body 21 is defined by the shape of the curved portion 70 (70L, 70R) provided on the side wall panel 68 (68L, 68R). In this embodiment, the curved portion 70 is arranged so as to connect three arcs when the side wall panel 68 is laid flat. In the curved portion 70, the central arc portion 75 located in the middle constitutes the most recessed area of the recess 35. The central arc portion 75 is a roughly arc-shaped portion with a radius dimension r of about 80 mm and a central angle α set to about 230°, and is shaped to curve gently and recess significantly. From the central arc portion 75 to the front area (front portion 74a) of the rear arc portion 74, the shape is such that it curves in an S-shape and continues. Furthermore, in the curved section 70, the separation distance D at the closest point between the front arc section 73 and the rear arc section 74 is greater than the radius dimension r of the central arc section 75, and is set to approximately 125 mm. In other words, the recess 35 defined by the outer shape of the curved section 70 in the side wall panel 68 is formed such that, when the bag body 21 is fully inflated, the lower end opens wide in the front-to-back direction, and while maintaining this wide state in the front-to-back direction, it recesses significantly upward. Therefore, if the bag body is not provided with an outer tether section, the bag body will unfold to bypass the monitor through the recess, but since the recess is formed to open wide in the front-to-back direction at the lower end (the bottom surface side of the bag body), the part of the bag body located behind the recess (the area at the lower end of the occupant side wall) will protrude significantly to the rear. Incidentally, if the outer tether is not provided, the bag body will unfold in a way that extends the roughly S-shaped curved area from the rear of the central arc that forms the periphery of the recess to the front of the rear arc, causing the rear lower end of the bag body, that is, the area at the lower end of the occupant's side wall, to protrude unnecessarily far downward and rearward.In the airbag device M of this embodiment, since the outer tether portion 55 is provided on the bag body 21, even with a configuration that has a recess 35 that is widely open in the front and rear and recesses significantly upward (deeply recessed), it is possible to accurately restrict 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) from protruding significantly downward and rearward when the bag body 21 is deployed and inflated.
[0037] Furthermore, in the airbag device M of this embodiment, the outer tether portion 55 that restricts the completed inflation shape of the bag body 21 is set such that its length L1 is approximately the same as the length L2 of the straight line connecting points P1 and P2, which correspond to the planned connecting portions 77F and 77B that will connect both ends of the outer tether portion 55 when the side wall panel 68 is laid flat. In other words, in this embodiment, the outer tether portion 55 can restrict the behavior of the area on the rear lower end 21c side of the bag body 21 during inflation (excessive protrusion to the rear and downward), but it is not configured to excessively pull the area on the rear lower end 21c side of the bag body 21 forward when the airbag 20 is fully inflated. Therefore, deformation of the bag body 21 when inflation is complete can be suppressed due to excessive pulling by the outer tether portion 55, and the occupant can be stably protected by the fully inflated bag body 21.
[0038] Incidentally, even without providing such a curved section, it is possible to form a recess by, for example, providing a sharply angled bend instead of a curved section at a similar position on the side wall panel. However, considering the manufacturing cost of the bag body (ease and speed of sewing the side wall panel and the peripheral wall panel), it is preferable to provide a gently curved section as in the embodiment rather than a sharply angled bend. In other words, the airbag used in the airbag device of the embodiment allows for easy sewing of the bag body, suppresses increases in manufacturing man-hours and costs, and can accurately protect the occupant when inflation is complete, even when installed in a vehicle with a monitor that partially protrudes between the occupant and the vehicle.
[0039] In the airbag 20 of this embodiment, the outer tether portion 55 is configured as a wide strip with a width dimension approximately equal to the width dimension of the lower wall portion 25 of the bag body 21, and is provided as a single unit. However, the external shape and number of outer tether portions are not limited to this embodiment. For example, the outer tether portion may be configured as a narrow strip or as a string-like material, with multiple units arranged side by side on the left and right sides.
[0040] Furthermore, although the embodiments have described a passenger-side airbag system positioned in front of the passenger seat as an example, the present invention is not limited to a passenger-side airbag system. For example, the present invention may be applied to a driver-side airbag system of the type that is mounted 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-side airbag system of this configuration, even if the steering wheel is positioned to protrude partially upward from the instrument panel, the rear surface of the steering wheel, as a protruding object, can be smoothly covered by the fully inflated airbag, thereby effectively protecting the driver. [Explanation of symbols]
[0041] 1...Instrument panel, 2...Top, 3...Rear, 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, 55...Outer tether, MP...Occupant, V...Vehicle, M...Passenger side airbag device (airbag device).
Claims
1. It is configured to have an airbag positioned on the upper side of the instrument panel, which can be inflated by introducing inflation gas into it, an inflator that supplies inflation gas to the airbag, and a storage area for storing the folded airbag and the inflator. In an airbag device configured such that when the airbag inflates by allowing inflation gas discharged from the inflator to flow into its interior, it protrudes upward from the storage area while expanding backward, The airbag is configured to include a bag body into which inflation gas is introduced to inflate, and an outer tether portion arranged on the outer circumferential surface of the bag body to regulate the completed shape of the bag body upon inflation. The bag body is configured such that, when fully inflated, it has a passenger side wall on its rear side capable of protecting a passenger seated in the front seat, and on the lower side of the area in front of the passenger side wall when fully inflated, it has a recess that curves upward to create a gap between it and the instrument panel. An airbag device characterized in that the outer tether portion is arranged to connect the rear lower end of the bag body when inflation is complete with the front edge of the recess, so that the rear lower end of the bag body when inflation is complete can be positioned close to the rear surface of the instrument panel.
2. The bag body is configured to expand so that a protrusion, which is positioned to partially protrude upward from the instrument panel, is located within the recess. The airbag device according to claim 1, characterized in that the outer tether portion is positioned close to the rear side of the protrusion when the bag body has finished inflating.