Airbag device and occupant protection device

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 including the airbag device.

Background Art

[0002] The airbag device disclosed in Patent Document 1 below includes an inflater that generates high-pressure gas upon impact input, and a bag body that inflates and deploys from the seat back of a vehicle seat upon receiving the supply of gas from the inflater. The bag body includes a body support portion that deploys on the side opposite to the seat back with the body of the occupant sitting on the vehicle seat sandwiched therebetween, and a pair of head support portions that deploy on both sides in the width direction of the vehicle seat with the head of the occupant sandwiched therebetween and are connected to the body support portion. A relief portion that penetrates vertically between the pair of head support portions in the deployed state and avoids the head of the occupant is formed in the bag body.

[0003] The airbag device disclosed in Patent Document 2 below includes an inflater and an airbag that is deployed by gas supplied from the inflater. The airbag has a rear inflation portion that deploys on the back side of the seat, a pair of side inflation portions that extend forward from both sides in the seat width direction of the rear inflation portion, and a pair of front inflation portions that extend from the pair of side inflation portions toward the center side and are interconnected 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 inflation portion, the side inflation portions, and the front inflation portions.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the airbag device disclosed in the above Patent Document 1, a body support portion (airbag body) that expands from the rear side of the seat to the front side of the seat with respect to the occupant is supported in a both-sided holding state by a pair of head support portions (front and rear chambers) that expand on both the left and right sides of the occupant's head. Similarly, in the airbag device disclosed in the above Patent Document 2, a pair of front inflation portions (airbag body) that expand from the rear side of the seat to the front side of the seat with respect to the occupant are supported in a both-sided holding state by a pair of side inflation portions (front and rear chambers) that expand on both the left and right sides of the occupant's head.

[0006] In each of the above prior arts, it is necessary for the airbag body to pass through a narrow gap between the occupant's head and the ceiling of the vehicle from the rear side of the seat to the front side of the seat. However, for example, when the airbag body starts to inflate before passing through the above gap, or when the friction between the head, the ceiling, and the airbag is large, etc., the airbag body may get stuck in the above gap, resulting in a possibility of poor deployment of the airbag.

[0007] In consideration of the above facts, an object of the present invention is to obtain an airbag device and an occupant protection device that can easily prevent poor deployment of an airbag that expands and deploys from the rear side of the seat to the front side of the upper part of the vehicle seat.

Means for Solving the Problems

[0008] The airbag device according to the first aspect includes an inflater that generates gas during a vehicle collision, and an airbag to which the gas is supplied and that expands and deploys from the rear side of the seat to the front side of the upper part of the vehicle seat. The airbag includes a pair of left and right front and rear extending portions that expand through both the left and right sides of the head of an occupant seated on the vehicle seat and expand toward the front side of the seat, and a front and rear chamber having a connecting portion that connects the front end portions of the pair of front and rear extending portions in the left-right direction of the seat. The gas is supplied through a communication hole located on the rear side of the seat of the connecting portion of the inflated and deployed front and rear chamber, and includes an airbag body that expands 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 by the expansion and deployment of the front and rear chamber.

[0009] In the airbag device according to the first aspect, gas generated from the inflator at the time of a vehicle collision is supplied to the airbag, and the airbag expands and deploys from the rear side to the front side of the seat above the vehicle seat. This airbag has a front-rear chamber and an airbag body. The front-rear chamber has a pair of left and right front-rear extending portions that expand and deploy toward the front side of the seat through both left and right sides of the head of an occupant seated on the vehicle seat, and a connecting portion that connects the front end portions of the pair of front-rear extending portions in the left-right direction of the seat. The airbag body is supplied with the above-mentioned gas through a communication hole located on the rear side of the seat of the connecting portion of the expanded and deployed front-rear chamber. This airbag body expands and deploys toward the rear side of the seat after passing through the gap between the ceiling of the vehicle and the head of the occupant from the rear side to the front side of the seat due to the expansion and deployment of the front-rear chamber. Thereby, it becomes easier to prevent the airbag body from being clogged in the above-mentioned gap, and it becomes easier to prevent poor deployment of the airbag.

[0010] In the airbag device according to the second aspect, in the first aspect, a constriction portion for narrowing the internal cross-sectional area of the connecting portion is provided on the upstream side of the flow of the gas with respect to the communication hole in the connecting portion of the front-rear chamber.

[0011] In the airbag device according to the second aspect, since the above-mentioned constriction portion is provided in the connecting portion of the front-rear chamber, it becomes difficult for gas to flow from the front-rear chamber to the airbag body. As a result, it becomes possible to delay the expansion and deployment of the airbag body, and it becomes easier for the airbag body to pass through the narrow gap between the head of the occupant and the ceiling of the vehicle.

[0012] In the airbag device according to the third aspect, in the first aspect, the opening area of the communication hole is set to be smaller than the total of the internal cross-sectional areas of the pair of front-rear extending portions.

[0013] In the airbag device according to the third aspect, since the opening area of the communication hole formed in the connecting portion between the front and rear chambers is set to be smaller than the total internal cross-sectional area of the pair of front and rear extending portions, it becomes difficult for gas to flow from the front and rear chambers through the communication hole into the airbag body. As a result, it is possible to delay the inflation and deployment of the airbag body, and the airbag body can more easily pass through the narrow gap between the occupant's head and the vehicle ceiling.

[0014] In the airbag device according to the fourth aspect, in any one of the first to third aspects, the front and rear chambers are configured such that two long base fabrics overlapped are sewn at a pair of long side edges at a pair of long side sewing portions, and before inflation and deployment, the pair of front and rear extending portions are folded in a roll fold in which the pair of long side sewing portions are located on the outer and inner circumferences. In the inflated and deployed state of each of the front and rear extending portions, the pair of long side sewing portions are arranged side by side in the sheet vertical direction.

[0015] According to the airbag device of the fourth aspect, the front and rear chambers are configured such that two long base fabrics overlapped are sewn at a pair of long side edges at a pair of long side sewing portions. Before inflation and deployment, the pair of front and rear extending portions are folded in a roll fold in which the pair of long side sewing portions are located on the outer and inner circumferences. In the inflated and deployed state of each of the front and rear extending portions, the pair of long side sewing portions are arranged side by side in the sheet vertical direction. Since the pair of long side sewing portions are more rigid than other portions in the front and rear extending portions, it becomes difficult for each of the front and rear extending portions to bend in the sheet vertical direction (that is, the direction in which the pair of long side sewing portions are arranged). As a result, it is easy to prevent the airbag from malfunctioning due to the bending of the front and rear extending portions.

[0016] The airbag device according to the fifth aspect includes, in any one of the first to fourth aspects, a guiding cloth attached to the pair of front and rear extending portions and having a lower surface friction coefficient than the airbag. Before inflation and deployment, the front side portion including the airbag body of the airbag is rolled up, and when the airbag is inflated and deployed, the rolled-up portion passes through the gap with the guiding cloth wound around the outside of the rolled-up portion.

[0017] According to the airbag device of the fifth aspect, guide cloth having a lower surface friction coefficient than the airbag is attached to a pair of front and rear extending portions of the front and rear chambers. Before inflation and deployment, the front portion of the airbag including the airbag body is rolled up. When the airbag is inflated and deployed, the above-mentioned rolled-up portion passes through the gap between the occupant's head and the vehicle ceiling with the guide cloth wound around the outside of the above-mentioned rolled-up portion. As a result, the rolled-up portion including the airbag body can easily pass through the above-mentioned gap smoothly.

[0018] The airbag device of the sixth aspect is, in the fifth aspect, in the airbag before inflation and deployment, the portion behind the rolled-up portion is pleated.

[0019] According to the airbag device of the sixth aspect, before inflation and deployment, the front portion of the airbag including the airbag body is rolled up, and the portion behind the rolled-up portion is pleated. When the airbag is inflated and deployed, the pleated portion expands and deploys forward of the seat first, and the rolled-up portion including the airbag body is pushed out forward of the seat. As a result, the rolled-up portion including the airbag body can easily pass through the gap between the occupant's head and the vehicle ceiling smoothly.

[0020] The airbag device of the seventh aspect is, in the fifth aspect or the sixth aspect, the guide cloth is formed to extend between the pair of front and rear extending portions and to extend on both sides in the front-rear direction of the seat with respect to the top of the head in the state during inflation and deployment of the airbag.

[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 extend between the pair of front and rear extending portions and to extend on both sides in the front-rear direction of the seat with respect to the top of the occupant's head in the state during inflation and deployment of the airbag. Thereby, when the airbag is inflated and deployed, the guide cloth can be stably interposed between the vehicle ceiling and the airbag and between the airbag and the occupant's head.

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

[0023] In the occupant protection device according to the eighth aspect, an airbag device is mounted on the rear side of the seat above the vehicle seat on which the occupant sits. Since this airbag device is of any one of the first to seventh aspects, the same effects as any one of the first to seventh aspects can be obtained.

Advantages of the Invention

[0024] As described above, in the airbag device and the occupant protection device according to the present invention, it is easy to prevent a malfunction in the deployment of the airbag that expands and deploys from the rear side to the front side of the seat above the vehicle seat.

Brief Description of the Drawings

[0025]

Figure 1

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Figure 10

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Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

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Figure 20

Figure 21

Figure 22

Mode for Carrying Out the Invention

[0026] <The First Embodiment> Hereinafter, the occupant protection device 10 according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 18. In each figure, some reference numerals may be omitted for easy viewing of the drawings. Also, the arrows FR, UP, LH, and RH appropriately marked in each figure indicate the front direction (travel direction), upward direction, left direction, and right direction of the vehicle, respectively. Hereinafter, when simply using the directions of front and rear, left and right, and up and down for explanation, unless otherwise specified, they indicate the front and rear in the vehicle front-rear direction, the left and right in the vehicle left-right direction, and the up and down in the vehicle up-down direction.

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

[0028] In FIGS. 1 to 5, a state where a dummy doll D for a collision test is seated on the seat cushion 14 of the vehicle seat 12 is illustrated as a model of an occupant (seated person) to be protected. The dummy doll D is, for example, AM50 (50th percentile of American adult males) of a dummy for a frontal collision test (Hybrid III). This dummy doll D is seated in a standard seating posture defined by the collision test method, and the vehicle seat 12 is located at a reference setting position corresponding to the seating posture. Hereinafter, for easy understanding of the explanation, the dummy doll D will be referred to as "occupant D".

[0029] The occupant D seated on the seat cushion 14 of the vehicle seat 12 is restrained to the vehicle seat 12 by a seat belt 22 provided in the seat belt device 20 (see FIGS. 1 to 3; not shown in FIGS. 4 and 5). The seat belt device 20 is a three-point seat belt device, and a so-called seat-mounted seat belt device in which a retractor, an anchor, and a 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 the module case 46 together with the pair of inflators 44 in a folded state. The module case 46 is formed in a hollow rectangular parallelepiped shape. This module case 46 is disposed at the rear of the upper part of the vehicle seat 12 (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 the vehicle body (not shown).

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

[0032] The front and rear chambers 34 are formed in a long bag shape by overlapping two long base fabrics 36 and 38 shown in FIG. 6 and sewing the peripheral edges at the sewing portion S1. In this sewing portion S1, the sewing line SL11 and the sewing line SL12 are sewn, the sewing line SL13 and the sewing line SL14 are sewn, the sewing line SL15 and the sewing line SL16 are sewn, and the sewing line SL17 and the sewing line SL18 are sewn. The sewing portion S11 between the sewing line SL11 and the sewing line SL12 and the sewing portion S12 between the sewing line S13 and the sewing line S14 correspond to the "long side sewing portion" in the present invention. In these long side sewing portions 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.

[0033] The airbag body 40 is formed in a bag shape by folding a single base fabric 42 shown in FIG. 8 along four fold lines L1, L2, L3, and L4 and sewing at the sewing portion S2. In this sewing portion S2, the sewing line SL21 and the sewing line SL22 are sewn, the sewing line SL23 and the sewing line SL24 are sewn, the sewing line SL25 and the sewing line SL26 are sewn, and the sewing line SL27 and the sewing line SL28 are sewn. The above 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 are a pair of left and right inflator housing portions 34C for housing a pair of inflators 44. The central portion in the longitudinal direction of the front and rear chambers 34 is a connecting portion 34B, and the portions between the connecting portion 34B and the pair of inflator housing portions 34C are respectively front and rear extending portions 34A. The pair of inflators 44 are combustion-type or cold gas-type cylinder inflators, and generate gas when operated. These inflators 44 are controlled in operation by a control device (not shown) and generate gas during a vehicle collision.

[0035] A pair of inflator housing portions 34C are arranged separately on the left and right sides within the module case 46. Each inflator 44 housed within each inflator housing portion 34C is arranged in a posture where the axial direction is along the vertical 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 penetrate through frames (not shown) of the inflator housing portion 34C, the module case 46, and the seat back 16, and nuts are screwed onto each stud bolt. Thereby, the inflator housing portion 34C, the inflator 44, and the module case 46 are fixed 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 forms a substantially T - shaped bag shape communicating with each front - and - rear extending portion 34A. The connecting portion 34B is sewn to the airbag body 40 at a sewing portion S3 (see FIGS. 6 and 8) provided at the central portion of the connecting portion 34B. The sewing portion S3 forms a substantially inverted trapezoid shape as an example. Inside the sewing portion S3, a communication hole 48 that communicates the inside of the connecting portion 34B and the inside of the airbag body 40 is formed. The communication hole 48 forms a substantially inverted trapezoid shape as an example. This communication hole 48 is constituted by a through - hole 50 formed in the base fabric 36 of the front - and - rear chamber 34 and a through - hole 52 formed in the base fabric 42 of the airbag body 40.

[0037] The two base fabrics 36, 38 constituting the front - and - rear chamber 34 are also sewn at a pair of left - and - right sewing portions S4 shown in FIG. 6. Thereby, a pair of constricted portions 35 are provided in the connecting portion 34B of the front - and - rear chamber 34. The pair of constricted portions 35 are arranged on the upstream side of the flow of the gas flowing in the front - and - rear chamber 34 with respect to the communication hole 48. The connecting portion 34B has its internal cross - sectional area (i.e., the flow - path cross - sectional area of the connecting portion 34B) narrowed at the pair of constricted portions 35. Instead of the sewing portion S4, a configuration in which the sewing portion S5 or the sewing portion S6 shown in FIG. 7 is provided may be adopted. Thereby, the way of narrowing the internal cross - sectional area at the pair of constricted portions 35 can be adjusted.

[0038] A pair of front and rear extending portions 34A, a connecting portion 34B, and an airbag body 40 are folded in a predetermined folding manner during normal times and housed in a module case 46. When a pair of inflators 44 operate, gas is generated in a pair of inflator housing portions 34C. The gas generated in the pair of inflator housing portions 34C flows toward the connecting portion 34B through the pair of front and rear extending portions 34A and is supplied into the airbag body 40 through a communication hole 48. Thereby, the airbag 32 expands and deploys in the order of the pair of front and rear extending portions 34A, the connecting portion 34B, and the airbag body 40. When the airbag 32 expands and deploys, a tear line (not shown) formed in the module case 46 is configured to be cleaved under the inflation pressure of the airbag 32. Thereby, the airbag 32 can expand and deploy outside the module case 46.

[0039] The pair of front and rear extending portions 34A that have expanded and deployed extend in the front-rear direction on both the left and right sides of the head H of the occupant D and face the head H with gaps on both the left and right sides. In the pair of front and rear extending portions 34A that have expanded and deployed, as shown in FIG. 9, a pair of long-side sewing portions S11, S12 are configured to be arranged side by side in the vertical direction. Note that in FIG. 9, for convenience of explanation, the illustration of the head H is omitted, and the pair of front and rear extending portions 34A are shown close to each other. The pair of front and rear extending portions 34A are pulled obliquely downward in the rear direction by a pair of left and right rear tethers 54 described later, so as to be inclined downward toward the front. The front end portions of the pair of front and rear extending portions 34A that have expanded and deployed are connected in the left-right direction by the expanded and deployed connecting portion 34B. As shown in FIG. 3, a front-rear chamber 34 including the pair of front and rear extending portions 34A and the connecting portion 34B expands and deploys in a U-shape that opens rearward in plan view.

[0040] As shown in FIGS. 1, 2, 4, and 5, at the center in the left-right direction of the expanded and deployed connecting portion 34B, there is provided an enlarged portion 34B1 whose dimension in the up-down direction is larger than those of the left and right end portions of the connecting portion 34B. This enlarged portion 34B1 protrudes downward from the left and right end portions of the connecting portion 34B. In this enlarged portion 34B1, the above-described communication hole 48 is formed. The communication hole 48 is located on the rear side of the center in the left-right direction of the expanded and deployed connecting portion 34B. The gas from the inflator 44 is supplied rearward into the airbag body 40 through the communication hole 48. Thereby, the airbag body 40 expands and deploys behind the connecting portion 34B and lags behind the front and rear chambers 34 toward the occupant D side (rear side).

[0041] The expanded and deployed airbag body 40 faces the head H, chest C, and abdomen B of the occupant D with a gap from the front side. The expanded and deployed airbag body 40 restrains the occupant D who moves forward by inertia due to the impact of a vehicle collision from the front side. When restraining the occupant, the front and rear chambers 34 are stretched 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 outer roll fold and stored in the module case 46. The outer roll fold is a roll fold in which the airbag 32 is folded in a roll shape from the front end side of the airbag 32 upward and rearward so as to fold the deployment process of the airbag 32 in the reverse direction in a side view. In other words, the airbag 32 is folded in a left-handed (clockwise) roll shape when viewed from the left side of the vehicle. In this outer roll fold, the pair of front and rear extending portions 34A of the front and rear chambers 34 are folded such that the long side sewing portion S11 is located on the inner peripheral side and the long side edge portion S12 is located on the outer peripheral side.

[0043] In the airbag 32 configured as described above, a pair of left and right rear tethers 54, a pair of left and right front upper tethers 56, and a pair of left and right front lower tethers 58 are attached. The rear tethers 54, the front upper tethers 56, and the front lower tethers 58 are configured in a long strip shape by, for example, a nylon-based or polyester-based cloth material. The cloth material constituting the rear tethers 54, the front upper tethers 56, and the front lower tethers 58 is configured to be less stretchable than the base cloths 36, 38 constituting the front and rear chambers 34 and the base cloth 42 constituting the airbag body 40. This degree of non-stretchability can be adjusted by the material and thickness of the cloth, etc.

[0044] Each one end portion of the pair of rear tethers 54 is respectively locked (sewn) to the longitudinal middle portion of the pair of front and rear extending portions 34A (specifically, the front portion of each of the inflated and deployed front and rear extending portions 34A). Each other end portion of the pair of rear tethers 54 is respectively locked to the seat back 16 or a vehicle body (not shown) on the rear side of the occupant D. In the inflated and deployed state of the airbag 32, the pair of rear tethers 54 extend in the front-rear direction below the pair of front and rear extending portions 34A. In this state, the pair of rear tethers 54 assume a posture inclined so as to descend rearward. Thereby, the pair of front and rear extending portions 34A are configured to be drawn diagonally downward rearward by the pair of rear tethers 54. Thereby, when the inflation and deployment of the airbag 32 is completed, the airbag 32 is suppressed from swinging in the vertical direction and the front-rear direction.

[0045] The pair of front upper tethers 56 connect the left and right side portions at the front of the upper part that inflates and deploys above the front and rear chambers 34 in the airbag body 40 and the front portions of the pair of front and rear extending portions 34A, respectively. Each one end portion of the pair of front upper tethers 56 is respectively sewn to the left and right side portions at the front of the upper part that inflates and deploys above the front and rear chambers 34 in the airbag body 40. Each other end portion of the pair of front upper tethers 56 is respectively sewn to the front portions of the pair of front and rear extending portions 34A. The pair of front upper tethers 56 suppress the airbag body 40 from rotating upward around the connecting portion 34B when the inflation and deployment of the airbag 32 is completed.

[0046] A pair of front lower tethers 58 connect the left and right side portions at the lower part that expand and deploy below the front and rear chambers 34 in the airbag body 40 and the front portions of the pair of front and rear extending portions 34A, respectively. Each one end of the pair of front lower tethers 58 is sewn to the left and right side portions at the lower part that expand and deploy below the front and rear chambers 34 in the airbag body 40, respectively. Each other end 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 suppress the airbag body 40 from rotating downward around the connecting portion 34B when the inflation and deployment of the airbag 32 are completed.

[0047] The above airbag device 30 includes 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 the information from the collision sensor, the control device can detect or predict the occurrence of various forms of frontal collisions (or the inevitability of a frontal collision) for the applicable vehicle for each collision form described later.

[0048] When the control device detects or predicts a frontal collision based on the information from the collision sensor, it operates the pair of inflators 44. The forms of frontal collisions in which the control device operates the inflator 44 include, in addition to a full wrap frontal collision, offset frontal collisions such as an oblique collision and a micro wrap collision.

[0049] When a pair of inflators 44 operate, due to the pressure of the gas generated within a pair of inflator housing portions 34C of the front and rear chambers 34, the pair of front and rear extending portions 34A are unfolded from the rear end side (base end side) by outward rolling and expand and deploy toward the front side. Due to the expansion and deployment of these pair of front and rear extending portions 34A, the front portion of the airbag 32 including the connecting portion 34B and the airbag body 40 is deployed toward the front side. At this time, as shown in FIGS. 11 and 12, the front portion of the airbag 32 passes through the gap G between the head H of the occupant D and the ceiling R of the vehicle from the rear side toward the front side. Thereafter, the gas supplied to the connecting portion 34B of the front and rear chambers 34 is supplied to the airbag body 40 through the communication hole 48. Thereby, as shown in FIG. 13, the airbag body 40 is configured to expand and deploy. Note that, in FIGS. 11 to 13, the airbag 32 is schematically illustrated. Also, in FIGS. 11 to 13, 13 is the front seat.

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

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

[0052] This airbag 32 has a front-rear chamber 34 and an airbag body 40. The front-rear chamber 34 has a pair of left and right front-rear extending portions 34A that expand and deploy forward through both left and right sides of the head H of the occupant D, and a connecting portion 34B that connects the front end portions of the pair of front-rear extending portions 34A in the left-right direction. The gas is supplied to the airbag body 40 through a communication hole 48 formed on the rear side surface of the connecting portion 34B of the inflated and deployed front-rear chamber 34. This airbag body 40 expands and deploys toward the occupant D side (rear side) after passing through the gap G between the ceiling R of the vehicle and the head H of the occupant D from the rear side to the front side due to the expansion and deployment of the front-rear chamber 34.

[0053] That is, in the present embodiment, the gas passing through the pair of front-rear extending portions 34A and the connecting portion 34B of the front-rear chamber 34 is supplied into the airbag body 40 from the communication hole 48 toward the rear side. Thereby, the airbag body 40 can be inflated and deployed sufficiently later than the front-rear chamber 34. As a result, the airbag body 40 expands and deploys after passing through the above-mentioned gap G due to the expansion and deployment of the front-rear chamber 34. This makes it easier to prevent the airbag body 40 from being clogged in the above-mentioned gap G, and thus it becomes easier to prevent a malfunction in the deployment of the airbag 32.

[0054] Further, according to the present embodiment, a pair of constricted portions 35 with a reduced internal cross-sectional area of the connecting portion 34B are provided on the upstream side of the flow of the gas with respect to the communication hole 48 in the connecting portion 34B of the front-rear chamber 34. Thereby, it becomes difficult for the gas to flow from the pair of front-rear extending portion 34A sides to the communication hole 48 side of the connecting portion 34B, and the gas supply to the airbag body 40 becomes even slower. As a result, it becomes possible to further delay the inflation and deployment of the airbag body 40, and it becomes 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] In addition, in the present 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, so that the gap between the airbag body 40 and the occupant D is reduced. As a result, since the occupant D is restrained by the airbag body 40 earlier, the initial restraint performance of the occupant D by the airbag body 40 can be improved.

[0056] In addition, in the present embodiment, the front and rear chambers 34 are configured such that two long base fabrics 36 and 38 that are overlapped are sewn at a pair of long side edges at a pair of long side sewing portions S11 and S12. Before inflation and deployment, a pair of front and rear extending portions 34A are folded by an outer roll fold in which a pair of long side sewing portions S11 and S12 are located on the outer and inner circumferences. In the inflated and deployed state of each front and rear extending portion 34A, a pair of long side sewing portions S11 and S12 are arranged side by side in the vertical direction. Since the pair of long side sewing portions S11 and S12 are more rigid than other portions in the front and rear extending portions 34A, it becomes difficult for each front and rear extending portion 34A to bend in the vertical direction (that is, the direction in which the pair of long side sewing portions S11 and S12 are arranged). As a result, it becomes easier to prevent a defective deployment of the airbag 32 caused by the bending of the front and rear extending portions 34A.

[0057] The above effects will be supplemented and explained using the comparative examples shown in FIGS. 14 and 15. In FIGS. 14 and 15, the same reference numerals are given to the same configurations as in the present embodiment. In this comparative example, in the inflated and deployed state of each front and rear extending portion 34A, a pair of long side sewing portions S11 and S12 are arranged side by side in the horizontal direction. In this comparative example, before inflation and deployment, a pair of front and rear extending portions 34A are folded by an outer roll fold in which a pair of long side sewing portions S11 and S12 are located on both sides in the axial direction. In this comparative example, since the pair of long side sewing portions S11 and S12 having high rigidity are located on both sides in the axial direction of the outer roll fold, the rigidity of the pair of long side sewing portions S11 and S12 does not effectively contribute to the vertical bending of each front and rear extending portion 34A. For this reason, there is a possibility that a defective deployment of the airbag 32 may occur due to the vertical bending of the front and rear extending portions 34A during inflation and deployment, but this can be avoided in the present embodiment.

[0058] Further, according to the present embodiment, when restraining the occupant D by the airbag 32, a pair of rear tethers 54, each having one end sewn to a pair of front and rear extending portions 34A of the front and rear chambers 34 and the other end locked to the seat back 16 or the vehicle body on the rear side of the seat with respect to the occupant D, pull the pair of front and rear extending portions 34A obliquely downward to the rear of the seat. The pair of rear tethers 54 are extended in the front - rear direction together with the front and rear chambers 34 when restraining the occupant by the airbag body 40. These rear tethers 54 receive and support the load applied from the occupant D to the airbag body 40 together with the front and rear chambers 34.

[0059] Moreover, by the above - mentioned pulling in by the pair of rear tethers 54, the vertical and front - rear swinging of the airbag 32 at the completion of inflation and deployment can be suppressed. Further, by the above - mentioned pulling in by the pair of rear tethers 54, the lower surfaces of the pair of front and rear extending portions 34A come into contact with the left and right shoulder portions K of the occupant D. Thereby, regardless of the physical differences of the occupant D, the vertical position of the airbag body 40 with respect to the head H of the occupant D can be stabilized.

[0060] Also, in the present embodiment, an upper front portion that expands and deploys above the front and rear chambers 34 in the airbag body 40 and a pair of front and rear extending portions 34A of the front and rear chambers 34 are connected to each other by a pair of front - upper tethers 56. Thereby, it is possible to prevent the inflated and deployed airbag body 40 from being inadvertently displaced (rotated) upward around the connecting portion 34B with respect to the front and rear chambers 34.

[0061] Furthermore, in the present embodiment, a lower portion that expands and deploys below the front and rear chambers 34 in the airbag body 40 and a pair of front and rear extending portions 34A of the front and rear chambers 34 are connected to each other by a pair of front - lower tethers 58. Thereby, it is possible to prevent the inflated and deployed airbag body 40 from being inadvertently displaced (rotated) downward around the connecting portion 34B with respect to the front and rear chambers 34.

[0062] Next, a modified example of the first embodiment will be described. FIG. 16 shows a first modified example of the front and rear chambers 34 in a developed view. In this first modified example, a pair of constriction portions 35 are formed by sewing two base fabrics 36 and 38 constituting the front and rear chambers 34 at a long sewing portion S7 shown in FIG. 16. FIG. 17 shows a second modified example of the front and rear chambers 34 in a developed view. In this second modified example, a pair of constriction portions 35 are formed by sewing two base fabrics 36 and 38 constituting the front and rear chambers 34 at two middle-state (circular) sewing portions S8 shown in FIG. 17. Also in the first modified example and the second modified example, the same effects as those of the first embodiment can be obtained.

[0063] FIG. 18 shows a modified example of the airbag body 40 in a developed view. 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 total internal cross-sectional area of the pair of front and rear extending portions 34A. Thereby, even if a pair of constriction portions 35 are not provided in the front and rear chambers 34, it becomes difficult for gas to flow from the front and rear chambers 34 to the airbag body 40, and it becomes possible to delay the inflation and deployment of the airbag body 40. As a result, the airbag body 40 can easily pass through the gap G between the head H and the ceiling R. Moreover, since the deployment timing of the airbag body 40 can be adjusted by optimizing the size of the communication hole 49, it is not necessary to add sewing portions S4, S5, S6, S7 or S8 to the front and rear chambers 34, and an increase in manufacturing cost is suppressed.

[0064] Next, a second embodiment of the present invention will be described. Regarding the configuration and operation that are basically the same as those of the first embodiment, the same reference numerals as those in the first embodiment are given and the description thereof is omitted.

[0065] <Second Embodiment> In FIG. 19, in the occupant protection device according to the second embodiment of the present invention, a state during the inflation and deployment of the airbag 32 is shown in a plan view. In FIG. 20, in the occupant protection device according to the second embodiment, a state during the airbag 32 passing through the gap G between the head H and the ceiling R during inflation and deployment is shown in a schematic side view. In FIG. 21, in the occupant protection device according to the comparative example, a state where the airbag 32 during inflation and deployment is clogged in the gap G between the head H and the ceiling R is shown in a side view. In FIG. 22, in the occupant protection device according to the second embodiment, a side view for explaining the roll folding and the bellows folding of the airbag 32 is shown. In FIGS. 19 and 22, the arrow A indicates the deployment direction of the airbag 32.

[0066] As shown in FIG. 19, in this embodiment, on a pair of front and rear extending portions 34A of the front and rear chambers 34, a guiding cloth 60 having a lower surface friction coefficient than that of the airbag 32 and the ceiling R is attached. For example, a non-coated cloth is used for this guiding cloth 60. This guiding cloth 60 is formed to extend between the pair of front and rear extending portions 34A and to extend to both sides in the front-rear direction with respect to the top P of the head H in a state during the inflation and deployment of the airbag 32. The rear end portion of the guiding cloth 60 is sewn to the pair of front and rear extending portions 34 at the pair of left and right sewing portions S9. Note that the illustration of the guiding cloth 60 is omitted in FIG. 22.

[0067] In this embodiment, before inflation and deployment, the airbag 32 has the front portion including the airbag body 40 roll-folded (outer roll-folded), the portion behind the outer roll-folded portion is pleated, and it is stored in the module case 46. In the folded airbag 32, the above-mentioned guide cloth 60 is roll-folded together with a part of the outer roll-folded portion. When the airbag 32 is inflated and deployed, as shown in FIG. 20, the outer roll-folded portion 32F passes through the gap G between the head H and the ceiling R with the guide cloth 60 wound around the outside of the outer roll-folded portion 32F. As a result, the outer roll-folded portion 32F including the airbag body 40 can easily pass through the gap G smoothly, so that, as in the comparative example shown in FIG. 21, the outer roll-folded portion 32F is caught by the head H and the ceiling R and clogged in the gap G, thereby preventing poor deployment of the airbag 32. In FIGS. 20 and 21, reference numeral 32R indicates the pleated portion.

[0068] Also, according to this embodiment, the above-mentioned guide cloth 60 is formed to extend between a pair of front and rear extending portions 34A and extend on both sides in the front-rear direction with respect to the top P of the head H in the state during inflation and deployment of the airbag 32. Thereby, when the airbag 32 is inflated and deployed, the guide cloth 60 can be stably interposed between the ceiling R and the airbag 32 and between the airbag 32 and the head H.

[0069] Furthermore, according to this embodiment, before inflation and deployment, the airbag 32 has the front portion including the airbag body 40 roll-folded (outer roll-folded), and the portion behind the outer roll-folded portion is pleated. As conceptually shown in FIG. 22, when the airbag 32 is inflated and deployed, the pleated portion 32R of the airbag 32 expands and deploys forward first, and the outer roll-folded portion 32F including the airbag body 40 is pushed forward. As a result, the outer roll-folded portion 32F including the airbag body 40 can easily pass through the gap G between the head H and the ceiling R smoothly. In FIG. 22, the pleated portion 32R expands and deploys in the order of 32R1→32R2, and the roll-folded portion 32F expands and deploys in the order of 32F1→32F2→32F3.

[0070] The present invention has been described above with reference to several embodiments and modifications. However, the present invention can be implemented with various changes without departing from the gist thereof. Needless to say, the scope of rights of the present invention is not limited to the above-described embodiments and modifications.

Explanation of Reference Numerals

[0071] 10 Occupant protection device 12 Vehicle seat 30 Airbag device 32 Airbag 32F Outer roll-fold portion (roll-fold portion) 34 Front and rear chambers 34A Front and rear extending portion 34B Connecting portion 35 Narrow portion 36 Base fabric 38 Base fabric 40 Airbag body 44 Inflator 48 Communication hole 49 Communication hole 60 Guide fabric D Occupant H Head R Ceiling S11, S12 Long side sewing portion

Claims

1. An inflator that generates gas upon a vehicle collision, an airbag to which the gas is supplied and that expands and deploys from the rear side to the front side of the upper part of a vehicle seat, and the airbag has a front-rear chamber having a pair of left and right front-rear extending portions that expand and deploy from both left and right sides of the head of an occupant seated on the vehicle seat toward the front side of the seat, and a connecting portion that connects the front end portions of the pair of front-rear extending portions in the left-right direction of the seat, the gas is supplied through a communication hole located on the rear side of the seat of the connecting portion of the expanded and deployed front-rear chamber, and an airbag main body that expands 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 to the front side of the seat by the expansion and deployment of the front-rear chamber, and the front-rear chamber is configured such that two long base fabrics that are overlapped are sewn at a pair of long side edge portions at a pair of long side sewing portions, before expansion and deployment, the pair of front-rear extending portions are folded in a roll fold in which the pair of long side sewing portions are located on the outer periphery and the inner periphery, An airbag device in which, in the expanded and deployed state of each of the front-rear extending portions, the pair of long side sewing portions are arranged side by side in the up-down direction of the seat.

2. An inflator that generates gas upon a vehicle collision, an airbag to which the gas is supplied and that expands and deploys from the rear side to the front side of the upper part of a vehicle seat, and the airbag has a front-rear chamber having a pair of left and right front-rear extending portions that expand and deploy from both left and right sides of the head of an occupant seated on the vehicle seat toward the front side of the seat, and a connecting portion that connects the front end portions of the pair of front-rear extending portions in the left-right direction of the seat, the gas is supplied through a communication hole located on the rear side of the seat of the connecting portion of the expanded and deployed front-rear chamber, and an airbag main body that expands 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 to the front side of the seat by the expansion and deployment of the front-rear chamber, and is provided with a guiding cloth that is attached to the pair of front-rear extending portions and has a lower coefficient of surface friction than the airbag, before expansion and deployment, the front side portion of the airbag including the airbag main body is folded in a roll fold, An airbag device in which, when the airbag expands and deploys, the roll fold portion passes through the gap with the guiding cloth wound around the outside of the roll fold portion.

3. The airbag device according to claim 2, wherein, before inflation and deployment, a portion of the airbag behind the roll-folded portion is pleated.

4. The airbag device according to claim 2 or claim 3, wherein the guide cloth is formed to extend between the pair of front and rear extending portions and to extend on both sides in the sheet front-rear direction with respect to the top of the head in a state during inflation and deployment of the airbag.

5. A vehicle seat on which an occupant sits, The airbag device according to claim 1 or claim 2, mounted on the rear side of the seat at the upper part of the vehicle seat, An occupant protection device comprising the same.

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