Airbag devices and occupant protection devices

Abstract

To prevent poor deployment of an airbag inflated and deployed from a seat rear side of an upper part of a vehicle seat to a seat front side.SOLUTION: An airbag device 30 comprises an airbag 32 supplied with gas upon vehicle collision to be inflated and deployed from a seat rear side of an upper part of a vehicle seat 12 to a seat front side. The airbag 32 comprises a front-rear chamber 34 and an airbag body 40. The front-rear chamber 34 comprises: a pair of left and right front-rear extension parts 34A that passes through left and right sides of a head H of an occupant D and is inflated and deployed to the seat front side; and a connection part 34B connecting front end parts of the pair of front-rear extension parts 34A in a seat left-right direction. The airbag body 40 is supplied with gas through a communication hole located at a seat rear side of the connection part 34B of the front-rear chamber 34 inflated and deployed. Due to inflation and deployment of the front-rear chamber 34, the airbag body 40 passes through a gap between a vehicle ceiling and the head H from the seat rear side to the seat front side, and is then inflated and deployed toward the seat rear side.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an airbag device and an occupant protection device equipped with an airbag device. [Background technology]

[0002] The airbag device disclosed in Patent Document 1 listed below includes an inflator that generates high-pressure gas when an impact is applied, and a bag body that receives gas from the inflator and inflates and deploys from a seatback of a vehicle seat. The bag body includes a torso support portion that deploys on the side opposite the seatback to sandwich the torso of an occupant seated in the vehicle seat, and a pair of head support portions that deploy on both sides in the width direction of the vehicle seat to sandwich the occupant's head and are connected to the torso support portion. The bag body has a relief portion that penetrates vertically between the pair of head support portions in a deployed state and avoids the occupant's head.

[0003] The airbag device disclosed in Patent Document 2 below includes an inflator and an airbag that deploys with gas supplied from the inflator. The airbag has a rear inflatable section that deploys on the backside of the seat, a pair of side inflatable sections that extend forward from both sides of the rear inflatable section in the seat width direction, and a pair of front inflatable sections that extend from the pair of side inflatable sections toward the center and are connected to each other at the center to cover the front of the occupant. In this airbag, a gas flow path is formed in the order of the rear inflatable section, the side inflatable sections, and the front inflatable sections. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-018593 [Patent Document 2] Japanese Patent Application Publication No. 2019-218013 Summary of the Invention [Problem to be solved by the invention]

[0005] In the airbag device disclosed in Patent Document 1, a body support portion (airbag body) that deploys from the rear side of the seat to the front side of the seat relative to the occupant is supported in a double-sided manner by a pair of head support portions (front and rear chambers) that deploy on both the left and right sides of the occupant's head. Similarly, in the airbag device disclosed in Patent Document 2, a pair of front inflatable portions (airbag body) that deploy from the rear side of the seat to the front side of the seat relative to the occupant are supported in a double-sided manner by a pair of side inflatable portions (front and rear chambers) that deploy on both the left and right sides of the occupant's head.

[0006] In each of the above-mentioned prior arts, the airbag body must pass through the narrow gap between the occupant's head and the vehicle ceiling from the rear side of the seat to the front side of the seat. However, if the airbag body starts to inflate before passing through the gap, or if there is a large amount of friction between the head and the ceiling and the airbag, the airbag body may become stuck in the gap, resulting in poor deployment of the airbag.

[0007] SUMMARY OF THE INVENTION In consideration of the above, an object of the present invention is to provide an airbag device and an occupant protection device that can easily prevent improper deployment of an airbag that inflates and deploys from the rear side of the upper part of a vehicle seat to the front side of the seat. [Means for solving the problem]

[0008] The airbag device of the first aspect includes an inflator that generates gas in the event of a vehicle collision, and an airbag that is supplied with the gas and inflates and deploys from the rear side of the seat above the vehicle seat to the front side of the seat, the airbag including a pair of left and right front and rear extending portions that inflate and deploy toward the front side of the seat, passing through both the left and right sides of the head of an occupant seated in the vehicle seat, and a front and rear chamber having a connecting portion that connects the front ends of the pair of front and rear extending portions in the left and right direction of the seat, and an airbag body that is supplied with the gas through a communication hole located on the rear side of the seat of the connecting portion of the inflated front and rear chambers, and that inflates and deploys toward the rear side of the seat after passing through the gap between the ceiling of the vehicle and the head from the rear side of the seat to the front side of the seat as the front and rear chambers inflate and deploy.

[0009] In the airbag device of the first aspect, gas generated by an inflator is supplied to the airbag during a vehicle collision, causing the airbag to inflate and deploy from the rear side of the upper portion of the vehicle seat toward the front side of the seat. This airbag has front and rear chambers and an airbag body. The front and rear chambers have a pair of left and right front and rear extensions that inflate and deploy toward the front side of the seat, passing over the left and right sides of the head of an occupant seated in the vehicle seat, and a connecting portion that connects the front ends of the pair of front and rear extensions in the left-right direction of the seat. The gas is supplied to the airbag body through a communication hole located on the rear side of the connecting portion of the inflated and deployed front and rear chambers. The airbag body passes through the gap between the vehicle ceiling and the occupant's head from the rear side of the seat to the front side of the seat, and then inflates and deploys toward the rear side of the seat as the front and rear chambers inflate and deploy. This makes it easier to prevent the airbag body from getting stuck in the gap, making it easier to prevent poor airbag deployment.

[0010] The airbag device of the second aspect is the same as that of the first aspect, wherein the connecting portion of the front and rear chambers is provided with a narrowed portion that narrows the internal cross-sectional area of ​​the connecting portion, upstream of the communication hole in the gas flow direction.

[0011] In the airbag device of the second aspect, the narrowed portion is provided at the connecting portion between the front and rear chambers, making it difficult for gas to flow from the front and rear chambers to the airbag body, which delays the inflation and deployment of the airbag body and makes it easier for the airbag body to pass through the narrow gap between the occupant's head and the vehicle ceiling.

[0012] The airbag device of the third aspect is the first aspect, wherein the opening area of ​​the communication hole is set smaller than the total internal cross-sectional area of ​​the pair of front and rear extending portions.

[0013] In the airbag device of the third aspect, the opening area of ​​the communication hole formed in the connecting portion of the front and rear chambers is set smaller than the sum of the internal cross-sectional areas of the pair of front and rear extending portions, making it difficult for gas to flow from the front and rear chambers through the communication hole to the airbag body, which delays inflation and deployment of the airbag body and makes it easier for the airbag body to pass through the narrow gap between the occupant's head and the vehicle ceiling.

[0014] The airbag device of the fourth aspect is any one of the first to third aspects, in which the front and rear chambers are configured by two overlapping long base fabrics sewn together at a pair of long side edges at a pair of long side stitching portions, and before inflation and deployment, the pair of front and rear extending portions are folded in a roll fold with the pair of long side stitching portions located on the outer and inner circumferences, and when each of the front and rear extending portions is in an inflated and deployed state, the pair of long side stitching portions are arranged side by side in the vertical direction of the seat.

[0015] According to the airbag device of the fourth aspect, the front and rear chambers are configured by sewing a pair of long edge portions of two overlapping long base fabrics together at a pair of long-side sewn portions. Before inflation and deployment, the pair of front and rear extensions are folded in a rolled manner with the pair of long-side sewn portions located on the outer and inner peripheries. When each front and rear extension is in an inflated and deployed state, the pair of long-side sewn portions are aligned in the up-down direction of the seat. Because the pair of long-side sewn portions are more rigid than other portions of the front and rear extensions, each front and rear extension is less likely to bend in the up-down direction of the seat (i.e., the direction in which the pair of long-side sewn portions are aligned). As a result, poor deployment of the airbag due to bending of the front and rear extensions is more easily prevented.

[0016] The airbag device of the fifth aspect is any one of the first to fourth aspects, and is provided with a guide cloth attached to the pair of front and rear extending portions and having a surface friction coefficient lower than that of the airbag, and before inflation and deployment, the airbag has a front portion including the airbag body folded in a roll, and when the airbag is inflated and deployed, the rolled portion passes through the gap with the guide cloth wrapped around the outside of the rolled portion.

[0017] According to the airbag device of the fifth aspect, a guide cloth having a surface with a lower coefficient of friction than the airbag is attached to the pair of front and rear extending portions of the front and rear chambers. Before inflation and deployment, the airbag has a front portion including the airbag body folded in a roll. When the airbag is inflated and deployed, the rolled portion passes through the gap between the occupant's head and the vehicle ceiling with the guide cloth wrapped around the outside of the rolled portion. This makes it easier for the rolled portion including the airbag body to pass through the gap smoothly.

[0018] In the airbag device of a sixth aspect, in the fifth aspect, the airbag before inflation and deployment is folded in an accordion-like manner at a portion rearward of the roll-folded portion.

[0019] According to the airbag device of the sixth aspect, before inflation and deployment, the airbag has a front portion including the airbag body folded in a roll, and a portion rearward of the rolled portion folded in an accordion-like manner. When the airbag is inflated and deployed, the accordion-like portion inflates and deploys toward the front of the seat first, pushing the rolled portion including the airbag body toward the front of the seat. As a result, the rolled portion including the airbag body can easily pass through the gap between the occupant's head and the vehicle ceiling.

[0020] The airbag device of the seventh aspect is the fifth or sixth aspect, wherein the guide cloth is formed to a size that extends between the pair of front and rear extending portions when the airbag is in the middle of inflating and deploying, and extends on both sides of the top of the head in the front-to-rear direction of the seat.

[0021] According to the airbag device of the seventh aspect, the guide cloth attached to the pair of front and rear extending portions of the front and rear chambers is formed to a size that extends between the pair of front and rear extending portions and extends on both sides of the top of the occupant's head in the seat front-rear direction when the airbag is in the middle of inflating and deploying, thereby allowing the guide cloth to be stably interposed between the vehicle ceiling and the airbag and between the airbag and the occupant's head when the airbag is inflated and deploying.

[0022] The occupant protection device of the eighth aspect includes a vehicle seat on which an occupant sits, and an airbag device of any one of the first to seventh aspects mounted on the rear side of the upper part of the vehicle seat.

[0023] In the occupant protection device of the eighth aspect, an airbag device is mounted on the rear side of the upper part of the vehicle seat on which the occupant sits. This airbag device is one of the first to seventh aspects, and therefore provides the same effects as any one of the first to seventh aspects. [Effects of the Invention]

[0024] As described above, the airbag device and occupant protection device according to the present invention can easily prevent improper deployment of the airbag that inflates and deploys from the rear side of the upper part of the vehicle seat toward the front side of the seat. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a perspective view showing a state in which an airbag is inflated and deployed in an occupant protection device according to a first embodiment. [Figure 2] 2 is a side view showing the configuration shown in FIG. 1 as viewed from the left side of the vehicle. [Figure 3] 2 is a plan view showing the configuration shown in FIG. 1 as seen from above the vehicle. [Figure 4] 2 is a front view showing the configuration shown in FIG. 1 as seen from the front of the vehicle. [Figure 5] FIG. 5 is a front view showing the airbag in FIG. 4 in a see-through state. [Figure 6] FIG. 2 is an exploded view of the front and rear chambers of the airbag. [Figure 7] FIG. 7 is an enlarged view showing a part of FIG. 6. [Figure 8] FIG. 2 is a development view of an airbag body provided in the airbag. [Figure 9] 10 is a cross-sectional view showing a state in which a pair of front and rear extension portions provided in the front and rear chambers are in the middle of being inflated and deployed. FIG. [Figure 10] FIG. 2 is a perspective view showing a part of the front-rear extending portion. [Figure 11] FIG. 10 is a side view showing a state in which the airbag is passing through the gap between the occupant's head and the vehicle ceiling in the early stage of inflation and deployment. [Figure 12] FIG. 12 is a side view corresponding to FIG. 11, illustrating the airbag in the middle stage of inflation and deployment. [Figure 13] FIG. 12 is a side view corresponding to FIG. 11, showing a state in which inflation and deployment of the airbag has been completed. [Figure 14] 10 is a cross-sectional view showing a state in which a pair of front and rear extension portions provided in the front and rear chambers according to the comparative example are in the middle of being inflated and deployed. FIG. [Figure 15] 15 is a perspective view showing a part of the front-to-rear extending portion shown in FIG. 14. FIG. [Figure 16] FIG. 10 is a development view showing a first modified example of the front and rear chambers. [Figure 17] FIG. 10 is a development view showing a second modified example of the front and rear chambers. [Figure 18] FIG. 10 is a development view showing a modified example of the airbag body. [Figure 19] FIG. 10 is a plan view showing an airbag in the middle of inflation and deployment in an occupant protection device according to a second embodiment. [Figure 20] FIG. 10 is a side view showing a state in which an airbag in the middle of inflation and deployment passes through a gap between the head of an occupant and the ceiling of a vehicle in an occupant protection device according to a second embodiment. [Figure 21] 10 is a side view showing a state in which an airbag in the middle of inflation and deployment is stuck in a gap between the head of an occupant and the ceiling of a vehicle in an occupant protection device according to a comparative example. FIG. [Figure 22] FIG. 10 is a side view illustrating roll-folding and accordion-folding of the airbag in the occupant protection device according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0026] First Embodiment An occupant protection device 10 according to a first embodiment of the present invention will be described below with reference to Figures 1 to 18. Note that in each figure, some reference numerals may be omitted to make the drawings easier to understand. Arrows FR, UP, LH, and RH, which are appropriately shown in each figure, respectively indicate the forward direction (direction of travel), upward direction, leftward direction, and rightward direction of the vehicle. Hereinafter, when the terms "front-rear," "left-right," and "up-and-down" are used in the description, they refer to "front-rear" in the front-rear direction of the vehicle, "left-right" in the left-right direction of the vehicle, and "up-and-down" in the up-and-down direction of the vehicle, unless otherwise specified.

[0027] As shown in Figures 1 to 5, the occupant protection device 10 is composed of a vehicle seat 12 and an airbag device 30. Here, the vehicle seat 12 is a rear seat of a vehicle (automobile), but it may also be a front seat. The vehicle seat 12 has a seat cushion 14, a seat back 16 erected above the rear end of the seat cushion 14, and a headrest 18 connected to the upper end of the seat back 16. The front-rear, left-right, up-down directions of the vehicle seat 12 coincide with the front-rear, left-right, up-down directions of the vehicle.

[0028] 1 to 5, a crash test dummy D is shown as a model of the occupant (seat occupant) to be protected, seated on the seat cushion 14 of the vehicle seat 12. The dummy D is, for example, a frontal crash test dummy (Hybrid III) AM50 (50th percentile of American adult males). The dummy D is seated in a standard seating position defined by the crash test method, and the vehicle seat 12 is positioned at a reference setting position corresponding to the seating position. For ease of understanding, the dummy D will be referred to as "occupant D" below.

[0029] An occupant D seated on the seat cushion 14 of the vehicle seat 12 is restrained in the vehicle seat 12 by a seat belt 22 (see FIGS. 1 to 3; not shown in FIGS. 4 and 5) provided in a seat belt device 20. The seat belt device 20 is a three-point seat belt device, and is a so-called seat-mounted seat belt device in which a retractor, anchor, and buckle (not shown) are provided on the vehicle seat 12.

[0030] The airbag device 30 includes an airbag 32, a pair of inflators 44 (see FIG. 6), and a module case 46. The airbag 32 is normally stored in a folded state in the module case 46 together with the pair of inflators 44. The module case 46 is formed in the shape of a hollow rectangular parallelepiped. The module case 46 is disposed behind the upper part of the vehicle seat 12 (more specifically, behind the upper end of the seat back 16 and the headrest 18), and is fixed to the upper end of the seat back 16 or to the vehicle body (not shown).

[0031] The airbag 32 receives gas supply from a pair of inflators 44 and inflates (deploys and inflates) from the rear side of the upper part of the vehicle seat 12 to the front side. The airbag 32 has front and rear chambers 34 and an airbag body 40. The front and rear chambers 34 have a pair of left and right front and rear extending portions 34A that inflate and deploy forward past the left and right sides of the head H of the occupant D, and a connecting portion 34B that connects the front ends of the pair of front and rear extending portions 34A in the left and right direction. The airbag body 40 inflates and deploys toward the occupant D (rear side) behind the front and rear chambers 34.

[0032] The front and rear chambers 34 are formed into a long bag shape by overlapping two long pieces of base fabric 36, 38 shown in FIG. 6 and sewing their peripheral edges together at a sewing section S1. At this sewing section S1, sewing lines SL11 and SL12 are sewn together, sewing lines SL13 and SL14 are sewn together, sewing lines SL15 and SL16 are sewn together, and sewing lines SL17 and SL18 are sewn together. The sewing section S11 between the sewing lines SL11 and SL12 and the sewing section S12 between the sewing lines S13 and S14 correspond to the "long side sewing sections" of the present invention. At these long side sewing sections S11 and S12, a pair of long side edges of the base fabric 36 and a pair of long side edges of the base fabric 38 are sewn together.

[0033] The airbag main body 40 is formed into a bag shape by folding a single piece of base fabric 42 shown in Fig. 8 along four fold lines L1, L2, L3, and L4 and sewing the folded piece at a sewn section S2. At the sewn section S2, a sewing line SL21 and a sewing line SL22 are sewn together, a sewing line SL23 and a sewing line SL24 are sewn together, a sewing line SL25 and a sewing line SL26 are sewn together, and a sewing line SL27 and a sewing line SL28 are sewn together. The base fabrics 36, 38, and 42 are made of, for example, a nylon-based or polyester-based fabric material.

[0034] Both longitudinal ends of the front and rear chambers 34 form a pair of left and right inflator housing sections 34C that house a pair of inflators 44. A central portion of the front and rear chambers 34 in the longitudinal direction forms a connecting section 34B, and the sections between the connecting section 34B and the pair of inflator housing sections 34C form front and rear extending sections 34A. The pair of inflators 44 are combustion-type or cold gas-type cylindrical inflators that generate gas when activated. The activation of these inflators 44 is controlled by a control device (not shown), and they generate gas when the vehicle collides.

[0035] The pair of inflator housings 34C are disposed separately on the left and right sides within the module case 46. Each inflator 44 housed in each inflator housing 34C is disposed with its axial direction aligned with the up-and-down direction of the seat back 16. Each inflator 44 is provided with, for example, a pair of upper and lower stud bolts. The pair of stud bolts penetrates the inflator housing 34C, the module case 46, and a frame (not shown) of the seat back 16, and a nut is threaded onto each stud bolt. This fixes the inflator housing 34C, the inflator 44, and the module case 46 to the frame of the seat back 16.

[0036] Each of the pair of front and rear extending portions 34A is formed in a long tubular shape. The connecting portion 34B is formed in a substantially T-shaped bag shape that communicates with each of the front and rear extending portions 34A. The connecting portion 34B is sewn to the airbag main body 40 at a sewn portion S3 (see FIGS. 6 and 8) provided in the center of the connecting portion 34B. The sewn portion S3 has a substantially inverted trapezoidal shape, for example. A communication hole 48 that communicates between the inside of the connecting portion 34B and the inside of the airbag main body 40 is formed on the inside of the sewn portion S3. The communication hole 48 has a substantially inverted trapezoidal shape, for example. The communication hole 48 is composed of a through-hole 50 formed in the base fabric 36 of the front and rear chambers 34 and a through-hole 52 formed in the base fabric 42 of the airbag main body 40.

[0037] The two base fabrics 36, 38 constituting the front and rear chambers 34 are also sewn together at a pair of left and right sewn portions S4 shown in FIG. 6. As a result, a pair of left and right narrowed portions 35 are provided in the connecting portion 34B of the front and rear chambers 34. The pair of narrowed portions 35 are positioned upstream of the flow of gas through the front and rear chambers 34 with respect to the communication holes 48. The connecting portion 34B has a narrowed internal cross-sectional area (i.e., the flow path cross-sectional area of ​​the connecting portion 34B) at the pair of narrowed portions 35. Note that instead of the sewn portion S4, a configuration may be adopted in which a sewn portion S5 or a sewn portion S6 shown in FIG. 7 is provided. This allows adjustment of the degree to which the internal cross-sectional area is narrowed at the pair of narrowed portions 35.

[0038] The pair of front and rear extending portions 34A, the connecting portion 34B, and the airbag main body 40 are normally folded in a predetermined manner and housed in the module case 46. When the pair of inflators 44 is activated, gas is generated in the pair of inflator housing portions 34C. The gas generated in the pair of inflator housing portions 34C flows through the pair of front and rear extending portions 34A toward the connecting portion 34B and is supplied to the airbag main body 40 through the communication holes 48. As a result, the airbag 32 inflates and deploys in the order of the pair of front and rear extending portions 34A, the connecting portion 34B, and the airbag main body 40. When the airbag 32 inflates and deploys, tear lines (not shown) formed on the module case 46 are configured to rupture under the inflation pressure of the airbag 32. This allows the airbag 32 to inflate and deploy outward from the module case 46.

[0039] The pair of inflated and deployed front-rear extending portions 34A extend in the front-rear direction on both the left and right sides of the head H of the occupant D, facing the head H with a gap between them. In the pair of inflated and deployed front-rear extending portions 34A, as shown in FIG. 9 , the pair of long-side sewn portions S11, S12 are arranged vertically side by side. For ease of explanation, FIG. 9 omits the illustration of the head H and depicts the pair of front-rear extending portions 34A close together. The pair of front-rear extending portions 34A are pulled diagonally downward and rearward by a pair of left and right rear tethers 54 (described later), thereby tilting forward and downward. The front ends of the pair of inflated and deployed front-rear extending portions 34A are connected in the left-right direction by the inflated and deployed connecting portion 34B. As shown in FIG. 3 , the front-rear chamber 34, including the pair of front-rear extending portions 34A and the connecting portion 34B, inflates and deploys in a U-shape that opens rearward in a plan view.

[0040] As shown in Figures 1, 2, 4, and 5, an expanded portion 34B1 having a larger vertical dimension than both left and right ends of the connecting portion 34B is provided in the left-right central portion of the inflated and deployed connecting portion 34B. This expanded portion 34B1 protrudes downward from both left and right ends of the connecting portion 34B. The aforementioned communication hole 48 is formed in this expanded portion 34B1. The communication hole 48 is located rearward of the left-right central portion of the inflated and deployed connecting portion 34B. Gas from the inflator 44 is supplied rearward through the communication hole 48 into the airbag body 40. As a result, the airbag body 40 inflates and deploys toward the occupant D (rearward) behind the connecting portion 34B, delayed from the front / rear chambers 34.

[0041] The inflated and deployed airbag body 40 faces the head H, chest C, and abdomen B of the occupant D from the front side with a gap therebetween. The inflated and deployed airbag body 40 restrains, from the front side, the occupant D who is inertially moving forward due to the impact of a vehicle collision. When the occupant is restrained, the front and rear chambers 34 are expanded in the front-rear direction, and the airbag body 40 is compressed in the front-rear direction.

[0042] The airbag 32 configured as described above is folded in a so-called outward roll-fold and stored in the module case 46. Outward roll-folding is a roll-folding in which the airbag 32 is folded from the front end side of the airbag 32 upward and rearward in a roll shape so as to fold in the reverse direction of the deployment process of the airbag 32 when viewed from the side. In other words, the airbag 32 is folded so as to be in a counterclockwise (clockwise) roll shape when viewed from the left side of the vehicle. In this outward roll-folding, the pair of front and rear extending portions 34A of the front and rear chambers 34 are folded so that the long side sewn portions S11 are located on the inner circumferential side and the long side edge portions S12 are located on the outer circumferential side.

[0043] The airbag 32 configured as described above is attached with a pair of left and right rear tethers 54, a pair of left and right upper front tethers 56, and a pair of left and right lower front tethers 58. The rear tethers 54, the upper front tethers 56, and the lower front tethers 58 are configured in the shape of long strips and made of, for example, a nylon-based or polyester-based fabric material. The fabric materials constituting the rear tethers 54, the upper front tethers 56, and the lower front tethers 58 are configured to be less stretchable than the base fabrics 36, 38 constituting the front and rear chambers 34 and the base fabric 42 constituting the airbag body 40. This resistance to stretch can be adjusted by the material and thickness of the fabric.

[0044] One end of each of the pair of rear tethers 54 is secured (sewn) to a longitudinally intermediate portion of the pair of front-rear extending portions 34A (more specifically, to a front portion of each of the inflated and deployed front-rear extending portions 34A). The other end of each of the pair of rear tethers 54 is secured to the seat back 16 or the vehicle body (not shown) rearward of the occupant D. When the airbag 32 is inflated and deployed, the pair of rear tethers 54 extend in the front-rear direction below the pair of front-rear extending portions 34A. In this state, the pair of rear tethers 54 are inclined downward and rearward. As a result, the pair of front-rear extending portions 34A are pulled diagonally downward and rearward by the pair of rear tethers 54. This prevents the airbag 32 from swinging up and down and in the front-rear direction when the airbag 32 is fully inflated and deployed.

[0045] The pair of front upper tethers 56 connect left and right sides of the front portion of the upper part of the airbag body 40 that inflates and deploys above the front and rear chambers 34 to the front portions of the pair of front and rear extending portions 34A. One end of each of the pair of front upper tethers 56 is sewn to the left and right sides of the front portion of the upper part of the airbag body 40 that inflates and deploys above the front and rear chambers 34. The other end of each of the pair of front upper tethers 56 is sewn to the front portions of the pair of front and rear extending portions 34A. The pair of front upper tethers 56 prevent the airbag body 40 from rotating upward about the connecting portions 34B when the airbag 32 has completed inflation and deployment.

[0046] The pair of front lower tethers 58 connect left and right portions of the lower part of the airbag body 40 that inflates and deploys downward from the front and rear chambers 34 to the front portions of the pair of front and rear extending portions 34A, respectively. One end of each of the pair of front lower tethers 58 is sewn to the left and right portions of the lower part of the airbag body 40 that inflates and deploys downward from the front and rear chambers 34. The other end of each of the pair of front lower tethers 58 is sewn to the front portions of the pair of front and rear extending portions 34A, respectively. The pair of front lower tethers 58 prevent the airbag body 40 from rotating downward about the connecting portions 34B when the airbag 32 has completed inflation and deployment.

[0047] The airbag device 30 is equipped with a control device (ECU), not shown, that controls the operation of the pair of inflators 44. The control device is electrically connected to the pair of inflators 44 and a collision sensor, not shown. Based on information from the collision sensor, the control device is capable of detecting or predicting the occurrence of various types of frontal collisions (or the inevitability of a frontal collision) for the vehicle to which it is applied, for each of the collision types described below.

[0048] When the control device detects or predicts a frontal collision based on information from the collision sensors, it activates the pair of inflators 44. Note that the types of frontal collisions for which the control device activates the inflators 44 include offset frontal collisions such as diagonal collisions and small overlap collisions in addition to full overlap frontal collisions.

[0049] When the pair of inflators 44 is activated, the pressure of gas generated in the pair of inflator housings 34C of the front and rear chambers 34 causes the pair of front and rear extending portions 34A to unfold from their rear end (base end) and inflate and deploy forward. The inflation and deployment of the pair of front and rear extending portions 34A causes the front portion of the airbag 32, including the connecting portion 34B and the airbag body 40, to deploy forward. At this time, as shown in FIGS. 11 and 12, the front portion of the airbag 32 passes from the rear to the front through the gap G between the head H of the occupant D and the vehicle ceiling R. Gas supplied to the connecting portion 34B of the front and rear chambers 34 then passes through the communication holes 48 and is supplied to the airbag body 40. This causes the airbag body 40 to inflate and deploy, as shown in FIG. 13. The airbag 32 is shown schematically in FIGS. 11 to 13. Also, in FIGS. 11 to 13, reference numeral 13 denotes a front seat.

[0050] (Action and effect) Next, the operation and effects of the first embodiment will be described.

[0051] The occupant protection device 10 according to this embodiment includes a vehicle seat 12 on which a vehicle (automobile) occupant D sits, and an airbag device 30 that protects the occupant D in the event of a vehicle collision. In this airbag device 30, gas generated from a pair of inflators 44 is supplied to an airbag 32 in the event of a vehicle collision, and the airbag 32 inflates and deploys from the rear side of the upper part of the vehicle seat 12 to the front side.

[0052] The airbag 32 has front and rear chambers 34 and an airbag body 40. The front and rear chambers 34 have a pair of left and right front and rear extending portions 34A that inflate and deploy forward, passing over both the left and right sides of the head H of the occupant D, and a connecting portion 34B that connects the front ends of the pair of front and rear extending portions 34A in the left-right direction. The gas is supplied to the airbag body 40 through communication holes 48 formed in the rear surface of the connecting portion 34B of the inflated front and rear chambers 34. As the front and rear chambers 34 inflate and deploy, the airbag body 40 passes through the gap G between the vehicle ceiling R and the head H of the occupant D from rearward to forward, and then inflates and deploys toward the occupant D (rearward).

[0053] That is, in this embodiment, gas that has passed through the pair of front-rear extending portions 34A and the connecting portion 34B of the front-rear chamber 34 is supplied rearward from the communication hole 48 into the airbag body 40. This allows the airbag body 40 to inflate and deploy into the front-rear chamber 34 with a sufficient delay. As a result, the airbag body 40 inflates and deploys after passing through the gap G due to the inflation and deployment of the front-rear chamber 34. This makes it easier to prevent the airbag body 40 from getting stuck in the gap G, making it easier to prevent poor deployment of the airbag 32.

[0054] Furthermore, according to this embodiment, the connecting portion 34B of the front and rear chambers 34 is provided with a pair of narrowed portions 35 that narrow the internal cross-sectional area of ​​the connecting portion 34B, on the upstream side of the gas flow relative to the communication holes 48. This makes it more difficult for gas to flow from the pair of front and rear extending portions 34A side to the communication holes 48 side of the connecting portion 34B, further slowing the supply of gas to the airbag body 40. As a result, it is possible to further delay the inflation and deployment of the airbag body 40, making it easier for the airbag body 40 to pass through the narrow gap G between the head H of the occupant D and the ceiling R of the vehicle.

[0055] Furthermore, in this embodiment, after the front and rear chambers 34 are inflated and deployed, the airbag body 40 is inflated and deployed toward the occupant D on the rear side of the connecting portion 34B, thereby reducing the gap between the airbag body 40 and the occupant D. As a result, the occupant D is restrained by the airbag body 40 early, thereby improving the initial restraint performance of the airbag body 40 on the occupant D.

[0056] In this embodiment, the front and rear chambers 34 are configured by sewing a pair of long edge portions of two overlapping elongated base fabrics 36, 38 at a pair of long-side sewn portions S11, S12. Before inflation and deployment, the pair of front and rear extending portions 34A are folded in an outward roll fold such that the pair of long-side sewn portions S11, S12 are located on the outer and inner peripheries. When each front and rear extending portion 34A is in an inflated and deployed state, the pair of long-side sewn portions S11, S12 are aligned vertically. Because the pair of long-side sewn portions S11, S12 are more rigid than other portions of the front and rear extending portion 34A, each front and rear extending portion 34A is less likely to bend vertically (i.e., in the direction in which the pair of long-side sewn portions S11, S12 are aligned). As a result, poor deployment of the airbag 32 due to the bending of the front and rear extending portion 34A is more easily prevented.

[0057] The above-described effects will be further explained using a comparative example shown in FIGS. 14 and 15. Note that in FIGS. 14 and 15, the same reference numerals are used to designate components similar to those in the present embodiment. In this comparative example, when each front and rear extension 34A is inflated and deployed, the pair of long side sewn portions S11, S12 are aligned in the left-right direction. In this comparative example, before inflation and deployment, the pair of front and rear extension 34A is folded in an outward rolled fold with the pair of long side sewn portions S11, S12 located on both axial sides. In this comparative example, because the pair of highly rigid long side sewn portions S11, S12 are located on both axial sides of the outward rolled fold, the rigidity of the pair of long side sewn portions S11, S12 does not effectively contribute to the up-down bending of each front and rear extension 34A. Therefore, the front and rear extension 34A may bend up-down during inflation and deployment, potentially resulting in poor deployment of the airbag 32. However, this can be avoided in the present embodiment.

[0058] Furthermore, according to this embodiment, when the airbag 32 restrains the occupant D, a pair of rear tethers 54, one end of which is sewn to the pair of front and rear extending portions 34A of the front and rear chamber 34 and the other end of which is anchored to the seat back 16 or the vehicle body on the seat rearward side of the occupant D, pull the pair of front and rear extending portions 34A diagonally downward and rearward of the seat. The pair of rear tethers 54 are stretched in the front-rear direction together with the front and rear chambers 34 when the airbag body 40 restrains the occupant D. Together with the front and rear chambers 34, these rear tethers 54 receive and support the load applied to the airbag body 40 by the occupant D.

[0059] Moreover, the retraction by the pair of rear tethers 54 can suppress the vertical and front-to-rear swinging of the airbag 32 when inflation and deployment is complete. Furthermore, the retraction by the pair of rear tethers 54 causes the lower surfaces of the pair of front-to-rear extending portions 34A to abut against the left and right shoulders K of the occupant D. This makes it possible to stabilize the vertical position of the airbag main body 40 with respect to the head H of the occupant D regardless of differences in physique of the occupant D.

[0060] In this embodiment, the front portion of the upper portion of the airbag body 40 that inflates and deploys upward from the front and rear chambers 34 is connected to the pair of front and rear extending portions 34A of the front and rear chambers 34 by a pair of front upper tethers 56. This makes it possible to prevent the inflated and deployed airbag body 40 from being accidentally displaced (rotated) upward about the connecting portions 34B relative to the front and rear chambers 34.

[0061] Furthermore, in this embodiment, the lower portion of the airbag body 40 that inflates and deploys downward from the front and rear chambers 34 and the pair of front and rear extending portions 34A of the front and rear chambers 34 are respectively connected by a pair of front lower tethers 58. This makes it possible to prevent the inflated and deployed airbag body 40 from being accidentally displaced (rotated) downward about the connecting portions 34B relative to the front and rear chambers 34.

[0062] Next, modifications of the first embodiment will be described. Fig. 16 shows a developed view of a first modification of the front and rear chamber 34. In this first modification, the two base fabrics 36, 38 that make up the front and rear chamber 34 are sewn together at the elongated sewn portion S7 shown in Fig. 16, thereby forming a pair of narrowed portions 35. Fig. 17 shows a developed view of a second modification of the front and rear chamber 34. In this second modification, the two base fabrics 36, 38 that make up the front and rear chamber 34 are sewn together at the two sandbar-shaped (circular) sewn portions S8 shown in Fig. 17, thereby forming a pair of narrowed portions 35. In the first and second modifications, the same effects as in the first embodiment can be obtained.

[0063] FIG. 18 shows a development view of a modified airbag body 40. In this modified example, a small-diameter communication hole 49 is formed in the airbag body 40. The opening area of ​​this communication hole 49 is set smaller than the opening area of ​​the communication hole 48 in the first embodiment. The opening area of ​​this communication hole 49 is set smaller than the sum of the internal cross-sectional areas of the pair of front and rear extending portions 34A. This makes it difficult for gas to flow from the front and rear chambers 34 to the airbag body 40, even without providing a pair of narrowed portions 35 in the front and rear chambers 34, thereby delaying the inflation and deployment of the airbag body 40. As a result, the airbag body 40 easily passes through the gap G between the head H and the ceiling R. Moreover, because the deployment timing of the airbag body 40 can be adjusted by optimizing the size of the communication hole 49, there is no need to add stitching portions S4, S5, S6, S7, or S8 to the front and rear chambers 34, which suppresses increases in manufacturing costs.

[0064] Next, a second embodiment of the present invention will be described. Note that the same reference numerals as in the first embodiment are used for the configurations and operations that are basically the same as those in the first embodiment, and the description thereof will be omitted.

[0065] <Second embodiment> Fig. 19 is a plan view showing a state in which the airbag 32 is in the middle of inflation and deployment in an occupant protection device according to a second embodiment of the present invention. Fig. 20 is a schematic side view showing a state in which the airbag 32 in the middle of inflation and deployment is in the middle of passing through the gap G between the head H and the ceiling R in an occupant protection device according to the second embodiment. Fig. 21 is a side view showing a state in which the airbag 32 in the middle of inflation and deployment is stuck in the gap G between the head H and the ceiling R in an occupant protection device according to a comparative example. Fig. 22 is a side view for explaining the roll-folding and accordion-folding of the airbag 32 in the occupant protection device according to the second embodiment. In Figs. 19 and 22, arrow A indicates the deployment direction of the airbag 32.

[0066] As shown in FIG. 19 , in this embodiment, a guide cloth 60 having a surface with a lower coefficient of friction than the airbag 32 and the ceiling R is attached to the pair of front and rear extending portions 34A of the front and rear chamber 34. For example, an uncoated fabric is used for the guide cloth 60. The guide cloth 60 is formed to a size that extends between the pair of front and rear extending portions 34A and on both sides of the top P of the head H in the front-rear direction when the airbag 32 is in the middle of inflating and deploying. The rear end of the guide cloth 60 is sewn to the pair of front and rear extending portions 34 at a pair of left and right sewn portions S9. Note that the guide cloth 60 is not shown in FIG. 22 .

[0067] In this embodiment, before inflation and deployment, the airbag 32 has a front portion including the airbag body 40 folded in a roll (outer roll fold), and a portion behind the outer roll fold in an accordion-like manner, and is housed in a module case 46. In the folded airbag 32, the guide cloth 60 is rolled together with a portion of the outer roll fold. When the airbag 32 is inflated and deployed, as shown in FIG. 20 , the outer roll fold portion 32F passes through the gap G between the head H and the ceiling R with the guide cloth 60 wrapped around the outside of the outer roll fold portion 32F. This allows the outer roll fold portion 32F including the airbag body 40 to pass through the gap G smoothly, thereby preventing poor deployment of the airbag 32 caused by the outer roll fold portion 32F getting caught on the head H or the ceiling R and getting stuck in the gap G, as in the comparative example shown in FIG. 21 . Note that in FIGS. 20 and 21 , reference numeral 32R denotes an accordion-like fold portion.

[0068] Furthermore, according to this embodiment, the guide cloth 60 is formed to a size that extends between the pair of front-rear extending portions 34A and extends on both front-rear directions relative to the top P of the head H when the airbag 32 is in the middle of inflating and deploying. This allows the guide cloth 60 to be stably interposed between the ceiling R and the airbag 32 and between the airbag 32 and the head H when the airbag 32 is inflated and deployed.

[0069] Furthermore, according to this embodiment, the airbag 32 before inflation and deployment has a front portion including the airbag body 40 that is outwardly rolled, and a portion behind the outer rolled portion that is accordion-folded. As conceptually shown in Fig. 22 , when the airbag 32 is inflated and deployed, the accordion-folded portion 32R of the airbag 32 inflates and deploys forward first, and the outer rolled portion 32F including the airbag body 40 is pushed forward. As a result, the outer rolled portion 32F including the airbag body 40 can easily pass through the gap G between the head H and the ceiling R. Note that in Fig. 22 , the accordion-folded portions 32R deploy in the order 32R1 → 32R2, and the rolled portions 32F deploy in the order 32F1 → 32F2 → 32F3.

[0070] Although the present invention has been described above with reference to several embodiments and modifications, the present invention can be practiced with various modifications without departing from the spirit of the invention. It goes without saying that the scope of the present invention is not limited to the above-described embodiments and modifications. [Explanation of symbols]

[0071] 10 Occupant protection devices 12 Vehicle seats 30 Airbag device 32 Airbag 32F Outer roll folding part (roll folding part) 34 Front and rear chambers 34A Front and rear extension part 34B Connection part 35 Stenosis 36 Base fabric 38 Base fabric 40 Airbag body 44 Inflator 48 Communication hole 49 Communication hole 60 induction cloth D. Crew H head R ceiling S11, S12 Long side seam

Claims

1. an inflator that generates gas when the vehicle crashes; an airbag that is supplied with the gas and inflates and deploys from the rear side of the upper portion of the vehicle seat to the front side of the seat; Equipped with The airbag is a front-rear chamber including a pair of left and right front-rear extending portions that inflate and deploy toward the front of the seat and pass through both left and right sides of the head of an occupant seated in the vehicle seat, and a connecting portion that connects front ends of the pair of front-rear extending portions in the left-right direction of the seat; an airbag body to which the gas is supplied via a communication hole located on the seat rear side of the connecting portion of the inflated and deployed front and rear chambers, and which passes through a gap between the head of the vehicle and the ceiling of the vehicle from the seat rear side to the seat front side as the front and rear chambers are inflated and deployed, and then inflates and deploys toward the seat rear side; and The front and rear chambers are configured by two overlapping long base fabrics sewn together at a pair of long side seams along a pair of long side edges, Before inflation and deployment, the pair of front and rear extending portions are folded in a roll-like manner such that the pair of long-side sewn portions are located on the outer periphery and the inner periphery, When the front and rear extending portions are inflated and deployed, the pair of long-side sewn portions are aligned in the seat up-down direction.

2. an inflator that generates gas when the vehicle crashes; an airbag that is supplied with the gas and inflates and deploys from the rear side of the upper portion of the vehicle seat to the front side of the seat; Equipped with The airbag is a front-rear chamber including a pair of left and right front-rear extending portions that inflate and deploy toward the front of the seat and pass through both left and right sides of the head of an occupant seated in the vehicle seat, and a connecting portion that connects front ends of the pair of front-rear extending portions in the left-right direction of the seat; an airbag body to which the gas is supplied via a communication hole located on the seat rear side of the connecting portion of the inflated and deployed front and rear chambers, and which passes through a gap between the head of the vehicle and the ceiling of the vehicle from the seat rear side to the seat front side as the front and rear chambers are inflated and deployed, and then inflates and deploys toward the seat rear side; and a guide cloth attached to the pair of front and rear extending portions and having a surface with a lower friction coefficient than the airbag; Before inflation and deployment, the airbag has a front portion including the airbag body folded into a roll, When the airbag is inflated and deployed, the rolled-up portion passes through the gap with the guide cloth wrapped around the outside of the rolled-up portion.

3. 3. The airbag device according to claim 2, wherein the airbag before inflation and deployment has a portion rearward of the rolled-up portion folded in an accordion-like manner.

4. 4. The airbag device according to claim 2, wherein the guide cloth is formed to a size that extends between the pair of front and rear extending portions and extends on both sides of the top of the head in the seat front-rear direction when the airbag is in the middle of inflating and deploying.

5. a vehicle seat for a passenger to sit on; the airbag device according to claim 1 or 2, which is mounted on an upper part of the vehicle seat on a rear side of the seat; An occupant protection device comprising:

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