Airbag device and occupant protection device

Abstract

To provide an airbag device enabling an occupant to quickly exit to outside a vehicle after a vehicle has had collision; and to provide an occupant protection device comprising the same.SOLUTION: An airbag device 30 comprises an airbag 32 supplied with gas generated in an inflator upon vehicle collision to be inflated and deployed from a rear side of a vehicle seat 12 to a front side through an upper side. The airbag 32 in an inflated and deployed state comprises: a pair of front-rear chambers 34 extending in a front-rear direction through left and right sides of a head of an occupant D; an airbag body 40 that is in communication with the pair of front-rear chambers 34 and is disposed at a front side of the occupant D between the pair of front-rear chambers 34; and a pair of rear tethers 54 each having one end part attached to the airbag body 40 and each having the other end part attached to a seatback 16 of the vehicle seat 12. At least the rear tether 54 on a side door side can be released after the vehicle collision.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 inflator that generates high-pressure gas when an impact is 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 inflator. The bag body includes a body support portion that deploys on the side opposite to the seat back with the body of an occupant sitting on the vehicle seat sandwiched therebetween, and a pair of head support portions that deploy on both sides in the seat width direction with the occupant's head sandwiched therebetween and are connected to the body support portion. Further, in the bag body, in the deployed state, a relief portion is formed that penetrates in the vertical direction between the pair of head support portions and avoids the occupant's head. Furthermore, this airbag device is provided with a connecting member that connects the deployed body support portion to the vehicle seat or the vehicle body.

[0003] The airbag device disclosed in Patent Document 2 below includes an inflator and an airbag that is deployed by gas supplied from the inflator. The airbag has a rear inflation portion that deploys on the back side of the seat, a pair of side inflation portions that extend from both sides in the width direction of the rear inflation portion toward the front side, and a pair of front inflation portions that extend from the pair of side inflation portions toward the center side and are connected to each other at the center side to cover the front of the occupant. Further, this airbag device is provided with a connecting member that connects a pair of support points provided on both sides in the seat width direction on the front side of the storage portion of the airbag and the airbag.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] As described above, the airbag device is provided with a connecting member that connects the airbag main body (bag body, airbag) to the vehicle seat or the vehicle body. Therefore, when the vehicle collides and the occupant attempts to escape (get out of the vehicle) after the collision, the connecting member on the side door side may become an obstacle and make it difficult to escape (hinder getting out of the vehicle).

[0006] Therefore, an object of the present invention is to provide an airbag device that allows an occupant to quickly escape from the vehicle after a vehicle collision, and an occupant protection device including the same.

Means for Solving the Problems

[0007] To achieve the above object, an airbag device according to a first aspect of the present invention includes an inflater that generates gas during a vehicle collision, and an airbag that is supplied with the gas generated by the inflater and expands and deploys from the rear side of the seat of the vehicle seat through the upper side of the seat to the front side of the seat. The airbag in the inflated and deployed state has a pair of front-rear chambers that extend in the front-rear direction of the seat through both left and right sides of the head of the occupant sitting on the vehicle seat, an airbag main body that communicates with the pair of front-rear chambers and is disposed on the front side of the seat of the occupant between the pair of front-rear chambers, and a pair of rear tethers, one end of which is attached to the airbag main body or the front-side portion of the seat of the pair of front-rear chambers, and the other end of which is attached to the seat back of the vehicle seat or the vehicle body. At least the rear tether on the side door side is configured to be releasable after the vehicle collision.

[0008] According to the invention of the first aspect, the gas generated by the inflator at the time of a vehicle collision is supplied to the airbag, and the airbag expands and deploys from the rear side of the vehicle seat through the upper side of the seat to the front side of the seat. The airbag in the inflated and deployed state has a pair of front and rear chambers extending in the front-rear direction of the seat through both left and right sides of the head of the occupant sitting on the vehicle seat, and an airbag body communicated with the pair of front and rear chambers and disposed on the front side of the occupant between the pair of front and rear chambers.

[0009] And this airbag has a pair of rear tethers, one end of which is attached to the airbag body or the front-side portion of the pair of front and rear chambers on the seat side, and the other end of which is attached to the seat back or the vehicle body of the vehicle seat, and at least the rear tether on the side door side is configured to be releasable after the vehicle collision. Therefore, by releasing the rear tether on the side door side after the vehicle collision, the occupant can quickly escape outside the vehicle. Here, the "time of collision" includes the time when the inevitability of the collision is predicted (foreseen).

[0010] Further, the airbag device according to the second aspect of the present invention is the airbag device according to the first aspect, and a detachable tongue is provided at the other end of the rear tether with respect to a buckle device attached to the seat back or the vehicle body of the vehicle seat.

[0011] According to the invention of the second aspect, a detachable tongue is provided at the other end of the rear tether with respect to a buckle device attached to the seat back or the vehicle body of the vehicle seat. Therefore, by pressing the release button of the buckle device, the rear tether is easily released. In this way, with a simple configuration, the rear tether is surely released, so that the occupant can quickly escape outside the vehicle after the vehicle collision.

[0012] Moreover, the airbag device according to the third aspect of the present invention is the airbag device according to the first aspect, wherein the rear tether is configured to be pulled toward the front side of the seat after a tensile load toward the front side of the seat due to restraining the occupant acts, and the other end portion is disengaged from the seat back or the vehicle body of the vehicle seat.

[0013] According to the invention of the third aspect, the rear tether is configured such that after a tensile load toward the front side of the seat due to restraining the occupant acts, the other end portion is disengaged from the seat back or the vehicle body of the vehicle seat when pulled toward the front side of the seat. That is, the rear tether is released by a simple operation of pulling toward the front side of the seat. Therefore, after a collision of the vehicle, the occupant can quickly escape from the vehicle.

[0014] Moreover, the airbag device according to the fourth aspect of the present invention is the airbag device according to the first aspect, wherein the rear tether is configured such that after a lapse of a predetermined time from the time of collision of the vehicle, the other end portion is disengaged from the seat back or the vehicle body of the vehicle seat.

[0015] According to the invention of the fourth aspect, the rear tether is configured such that after a lapse of a predetermined time from the time of collision of the vehicle, the other end portion is disengaged from the seat back or the vehicle body of the vehicle seat. That is, the rear tether is released without requiring a special operation. Therefore, after a collision of the vehicle, the occupant can quickly escape from the vehicle. Here, the "after a lapse of a predetermined time" means after the time when the amount of movement of the occupant toward the front side of the seat becomes maximum.

[0016] Moreover, the airbag device according to the fifth aspect of the present invention is the airbag device according to the fourth aspect, wherein the other end portion of the rear tether is configured to be disengaged by the operation of a squib or a micro gas generator.

[0017] According to the invention of the fifth aspect, when the squib or the micro gas generator operates, the other end of the rear tether is disengaged. That is, with a simple mechanism, the rear tether is quickly released. Therefore, after a vehicle collision, the occupant can quickly escape from the vehicle.

[0018] Moreover, the occupant protection device according to the sixth aspect of the present invention includes a vehicle seat on which an occupant sits, and an airbag device according to any one of the first to fifth aspects mounted on a portion on the rear side of the seat in the vehicle seat.

[0019] According to the invention of the sixth aspect, an airbag device is mounted on a portion on the rear side of the seat in the vehicle seat on which the occupant sits. Since this airbag device is of any one of the first to fifth aspects, the same operational effects as those of any one of the first to fifth aspects can be obtained.

[0020] Furthermore, the occupant protection device according to the seventh aspect of the present invention includes an inflater that generates gas during a vehicle collision, an airbag that is supplied with the gas generated by the inflater and expands and deploys from the rear side of the vehicle seat through the upper side of the seat to the front side of the seat, and a three-point seat belt device for restraining the occupant on the vehicle seat. The inflated and deployed airbag has a pair of front and rear chambers extending in the front-rear direction of the seat through both left and right sides of the head of the occupant sitting on the vehicle seat, an airbag body communicating with the pair of front and rear chambers and disposed on the front side of the seat of the occupant between the pair of front and rear chambers, and a rear tether having one end attached to the airbag body or a front-side portion of the pair of front and rear chambers on the seat side and the other end attached to the seat back or the vehicle body of the vehicle seat. The rear tether is provided only on the non-shoulder belt side of the seat belt device.

[0021] According to the invention of the seventh aspect, the gas generated by the inflator at the time of a vehicle collision is supplied to the airbag, and the airbag expands and deploys from the rear side of the vehicle seat through the upper side of the seat to the front side of the seat. The airbag in the inflated and deployed state has a pair of front and rear chambers extending in the front-rear direction of the seat through both left and right sides of the head of the occupant sitting on the vehicle seat, and an airbag body that communicates with the pair of front and rear chambers and is disposed on the front side of the occupant between the pair of front and rear chambers.

[0022] And this airbag has a rear tether with one end attached to the front side portion of the airbag body or the pair of front and rear chambers on the front side of the seat, and the other end attached to the seat back or the vehicle body of the vehicle seat. The rear tether is provided only on the non-shoulder belt side of the seat belt device. That is, the rear tether is not provided on the side door side which is the shoulder belt side of the seat belt device. Therefore, after the vehicle collision, the occupant can quickly escape from the vehicle.

Effect of the Invention

[0023] As described above, according to the present invention, after the vehicle collides, the occupant can quickly escape from the vehicle.

Brief Description of the Drawings

[0024]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Embodiments for Carrying out the Invention

[0025] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. For convenience of explanation, in each figure, the arrow UP shown as appropriate indicates the upward direction of the vehicle and the vehicle seat, the arrow FR indicates the forward direction of the vehicle and the vehicle seat, the arrow RH indicates the rightward direction of the vehicle and the vehicle seat, and the arrow LH indicates the leftward direction of the vehicle and the vehicle seat. Therefore, in the following description, when the directions of up and down, front and back, left and right are described without special mention, they indicate up and down, front and back, left and right in the vehicle and the vehicle seat. Also, the left-right direction is synonymous with the vehicle width direction and the seat width direction.

[0026] <First Embodiment> First, the first embodiment will be described. As shown in FIG. 1, the occupant protection device 10 according to the first embodiment is composed of a vehicle seat 12 and an airbag device 30. The vehicle seat 12 is a front seat or a rear seat of a vehicle (automobile). Here, instead of the front seat 13 (see FIGS. 5 to 7), the rear seat is used as the vehicle seat 12. This vehicle seat 12 has a seat cushion 14, a seat back 16 rotatably provided at the rear end of the seat cushion 14, and a headrest 18 vertically movably provided at the upper end of the seat back 16.

[0027] In addition, in FIG. 1 and the like, as a model of the occupant (seated person) to be protected, a dummy figure (human dummy) D for a collision test is shown in a state of sitting on the seat cushion 14 of the vehicle seat 12. The dummy figure D is, for example, AM50 (50th percentile of American adult males) of a dummy for a frontal collision test (Hybrid III). The dummy figure D is sitting in a standard sitting posture defined by the collision test method, and the vehicle seat 12 is located at a reference setting position corresponding to the sitting posture. Hereinafter, for easy understanding of the description, the dummy figure D is referred to as "occupant D".

[0028] As shown in FIGS. 1 and 2, the occupant D seated on the seat cushion 14 of the vehicle seat 12 is restrained to the vehicle seat 12 by the seat belt 22 provided in the seat belt device 20. 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 and an anchor (not shown) and a buckle are respectively provided on the vehicle seat 12.

[0029] The airbag device 30 includes an airbag 32, a pair of inflators 44 (see FIG. 3), 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 upper rear portion of the vehicle seat 12 (specifically, on the upper side of the seat back 16 and on the rear side of the headrest 18), and is fixed to the upper end portion of the seat back 16 or a vehicle body (not shown).

[0030] The airbag 32 is inflated and deployed (deployed and inflated) from the pair of inflators 44 from the rear side to the front side of the vehicle seat 12 through the upper side. 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 extending in the front-rear direction through both left and right sides of the head H of the occupant D, and a connecting portion 34B connecting the front end portions of the pair of front-rear extending portions 34A in the left-right direction. The airbag body 40 is inflated and deployed to the occupant D side (rear side) behind the connecting portion 34B with a delay with respect to the front-rear chamber 34, and is disposed between the pair of front-rear extending portions 34A and in front of the occupant D.

[0031] As shown in FIG. 3, the front and rear chambers 34 are formed in a long bag shape by overlapping two long base fabrics 36 and 38 and sewing their peripheral edges at the sewing portion S1. Further, as shown in FIG. 4, the airbag body 40 is formed in a bag shape by folding a single base fabric 42 along four fold lines L1, L2, L3, and L4 and sewing it at the sewing portion S2.

[0032] At the sewing portion S2, the sewing line S21 and the sewing line S22 are sewn, the sewing line S23 and the sewing line S24 are sewn, the sewing line S25 and the sewing line S26 are sewn, and the sewing line S27 and the sewing line S28 are sewn. The base fabrics 36, 38, and 42 are made of, for example, a polyamide-based or polyester-based fabric material. Further, one or both of the two base fabrics 36 and 38 constituting the front and rear chambers 34 are made of a base fabric that is less stretchable than the base fabric 42 constituting the airbag body 40.

[0033] As shown in FIG. 3, both longitudinal ends of the front and rear chambers 34 (the rear ends of the pair of front and rear extending portions 34A) are a pair of inflator accommodating portions 34C that accommodate a pair of inflators 44. That is, the central portion in the longitudinal direction of the front and rear chambers 34 (the portion connecting the front ends of the pair of front and rear extending portions 34A in the left-right direction) is the connecting portion 34B, and between the connecting portion 34B and the pair of inflator accommodating portions 34C are the front and rear extending portions 34A, respectively.

[0034] Although not shown, the airbag device 30 includes a control device (ECU) 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 (including a camera, etc.) not shown, and is configured to be able to detect a frontal collision of the vehicle or predict (hereinafter referred to as "prediction") the inevitability of a frontal collision. Then, when the control device detects or predicts a frontal collision of the vehicle based on the information from the collision sensor, it operates the pair of inflators 44.

[0035] The pair of inflators 44 are, for example, combustion-type or cold gas-type cylinder inflators, and are configured to generate gas by being actuated by a control device during a frontal collision of the vehicle. Note that the forms of frontal collision of the vehicle in which the control device actuates the inflators 44 include offset frontal collisions such as oblique collisions and micro-wrap collisions in addition to full-wrap frontal collisions.

[0036] The pair of inflator accommodating portions 34C that accommodate the pair of inflators 44 are arranged separately on the left and right sides within the module case 46. Each inflator 44 accommodated within each inflator accommodating portion 34C is arranged in a posture in which 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 (not shown).

[0037] The pair of stud bolts penetrate through frames (not shown) of the inflator accommodating portion 34C, the module case 46, and the seat back 16, and nuts (not shown) are screwed onto the respective stud bolts. Thereby, the inflator accommodating portion 34C, the inflator 44, and the module case 46 are fixed to the frame of the seat back 16.

[0038] The pair of front-and-rear extending portions 34A are each formed in a long tubular shape. And at the center in the left-right direction of the connecting portion 34B, an enlarged portion 34B1 that protrudes downward from both ends in the left-right direction of the connecting portion 34B to which the pair of front-and-rear extending portions 34A are connected is integrally formed. That is, the connecting portion 34B is formed in a substantially "T"-shaped bag shape communicating with each front-and-rear extending portion 34A. And a communication hole 48 is provided on the rear side of the center in the left-right direction of the connecting portion 34B including this enlarged portion 34B1.

[0039] That is, the periphery of the through hole 50 formed in the base fabric 36 of the front and rear chambers 34 and the periphery of the through hole 52 (see FIG. 4) formed in the base fabric 42 of the airbag body 40 are sewn to form a sewing portion S3, and the through hole 50 and the through hole 52 are communicated with each other to form a communication hole 48. Note that the through hole 50 and the through hole 52 are formed in a substantially inverted trapezoidal shape as an example. Therefore, the sewing portion S3 is formed in a substantially inverted trapezoidal shape as an example, and the communication hole 48 that communicates the inside of the connecting portion 34B and the inside of the airbag body 40 is positioned inside the sewing portion S3.

[0040] Further, the pair of front and rear extending portions 34A, the connecting portion 34B, and the airbag body 40 are folded in a predetermined folding manner such as roll folding or bellows folding during normal times and housed in the module case 46. A tear line (not shown) is formed in the module case 46. This tear line is configured to crack when receiving the inflation pressure of the airbag 32 during the inflation and deployment of the airbag 32. Thereby, the airbag 32 can be inflated and deployed outside the module case 46 in the order of the pair of front and rear extending portions 34A, the connecting portion 34B, and the airbag body 40.

[0041] Further, as shown in FIGS. 1 and 2, the pair of inflated and deployed front and 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, and face the head H with gaps on both the left and right sides. The front end portions of the pair of inflated and deployed front and rear extending portions 34A are connected in the left-right direction by the inflated and deployed connecting portion 34B. Thereby, the front and rear chambers 34 including the pair of front and rear extending portions 34A and the connecting portion 34B are configured to have a substantially "U" shape that opens backward in plan view (see FIG. 13).

[0042] In addition, the airbag body 40 is configured to be inflated and deployed rearward (toward the occupant D) when gas is supplied from the communication hole 48. That is, the airbag body 40 is configured to be inflated and deployed toward the occupant D side (rear side) behind the connecting portion 34B with a delay with respect to the front-rear chamber 34. Therefore, the airbag body 40 can pass through the gap between the head H of the occupant D and the ceiling 28 (see FIG. 5) of the passenger compartment from the rear side to the front side when the front-rear chamber 34 is inflated and deployed.

[0043] Then, the inflated and deployed airbag body 40 is configured to face the head H, chest C, and abdomen B of the occupant D with a gap in the front-rear direction (see FIG. 2). Note that the shape of the airbag body 40 at the time of its inflation and deployment is set so as to be sandwiched between the thigh portion F and the chest C of the occupant D from the middle stage to the late stage during occupant restraint.

[0044] Also, as shown in FIGS. 1 and 2, 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 to the airbag 32. The rear tethers 54, the front upper tethers 56, and the front lower tethers 58 are formed in a long strip shape, for example, by a polyamide-based or polyester-based fabric material. And the fabric 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 fabrics 36, 38 constituting the front-rear chamber 34 and the base fabric 42 constituting the airbag body 40. This degree of stretch resistance is adjusted by the material and thickness of the fabric.

[0045] The pair of front upper tethers 56 are configured to connect the left and right wall surfaces on the front side of the upper part that inflates and deploys above the front-rear chamber 34 in the airbag body 40 and the front parts of the pair of front-rear extending portions 34A, respectively. That is, each one end portion of the pair of front upper tethers 56 is sewn to the left and right wall surfaces on the front side of the upper part that inflates and deploys above the front-rear chamber 34 in the airbag body 40, respectively. And each other end portion of the pair of front upper tethers 56 is sewn to the front parts of the pair of front-rear extending portions 34A, respectively.

[0046] A pair of front lower tethers 58 are configured to connect the left and right wall surfaces on the front side of the lower part that expands and deploys below the front and rear chambers 34 in the airbag body 40, and the front parts of the pair of front and rear extending parts 34A, respectively. That is, each one end of the pair of front lower tethers 58 is sewn to the left and right wall surfaces on both sides of the lower part that expands and deploys below the front and rear chambers 34 in the airbag body 40. And each other end of the pair of front lower tethers 58 is sewn to the front parts of the pair of front and rear extending parts 34A, respectively.

[0047] On the other hand, each one end of the pair of rear tethers 54 is sewn and attached to the left and right wall surfaces on the front side of the lower part that expands and deploys below the front and rear chambers 34 in the airbag body 40. And each other end of the pair of rear tethers 54 is attached to the side part of the seat back 16 (or a vehicle body not shown on the rear side of the occupant D). Therefore, in the inflated and deployed state of the airbag 32, the pair of rear tethers 54 extend obliquely rearward and downward below the pair of front and rear extending parts 34A.

[0048] That is, the pair of rear tethers 54 adopt an inclined posture that inclines obliquely rearward and downward in a side view. Thereby, when restraining the occupant D by the airbag 32, the airbag body 40 is relatively pulled (drawn) obliquely rearward and downward by the pair of rear tethers 54, and the airbag body 40 and the front parts of the pair of front and rear extending parts 34A are relatively pulled obliquely rearward and downward with the module case 46 as the rotation center.

[0049] Also, among the other ends of the pair of rear tethers 54, at least the rear tether 54 on the side door side not shown is configured to be releasable after a vehicle collision. That is, this rear tether 54 is configured to be detachable from the side part of the seat back 16 (or a vehicle body not shown on the rear side of the occupant D).

[0050] Specifically, a tongue 24 (see FIG. 3) is attached to the other end of the rear tether 54. And a detachable buckle device 26 to which the tongue 24 is attached is fixed to the side portion of the seat back 16 (or a vehicle body not shown on the rear side of the occupant D). According to such a configuration, by pressing a release button (not shown) of the buckle device 26, the other end of the rear tether 54 can be easily detached (released).

[0051] Next, the operation of the airbag device 30 and the occupant protection device 10 according to the first embodiment configured as described above will be described.

[0052] When a frontal collision of the vehicle is detected (or predicted) by the collision sensor, a pair of inflators 44 are activated under the control of the control device. That is, gas is ejected from the inflators 44 respectively within the pair of inflator accommodation portions 34C. The gas generated within the pair of inflator accommodation portions 34C flows through the pair of front and rear extending portions 34A toward the connecting portion 34B side, and is supplied into the airbag main body 40 through the communication holes 48.

[0053] Specifically, first, as shown in FIG. 5, the tear line of the module case 46 is cleaved by the inflation pressure of the airbag 32, and the airbag 32 expands and deploys forward from the rear side to the upper side of the vehicle seat 12 (indicated by the arrow). That is, the airbag 32 expands forward from the upper rear portion of the seat back 16, passing above the headrest 18 and above the head H of the occupant D.

[0054] Next, as shown in FIG. 6, the head H of the occupant D is relatively inserted into the gap portion surrounded by the front and rear extending portions 34A of the pair of front and rear chambers 34 and the airbag main body 40 (see FIG. 7). That is, the front and rear extending portions 34A of the pair of front and rear chambers 34 are deployed forward while being arranged on both the left and right sides of the head H of the occupant D (indicated by the arrow).

[0055] And then, as shown in FIG. 7, the airbag body 40 is inflated and deployed toward the occupant D side (the rear side indicated by the arrow) by supplying gas from a connecting portion 34B that connects the front end portions in the front-rear extending portions 34A of the pair of front and rear chambers 34 in the left-right direction. That is, as shown in FIG. 2, the airbag body 40 is disposed between the pair of front and rear chambers 34 and on the front side of the occupant D.

[0056] When the airbag body 40 is inflated and deployed, a pair of front upper tethers 56 connect the left and right side portions on the front side of the upper part of the airbag body 40 and the front portions of the pair of front and rear extending portions 34A, respectively. By this pair of front upper tethers 56, when the inflation and deployment of the airbag body 40 (airbag 32) is completed, it is possible to suppress the inadvertent upward displacement (rotation) of the airbag body 40 around the connecting portion 34B with respect to the front and rear chambers 34.

[0057] When the airbag body 40 is inflated and deployed, a pair of front lower tethers 58 connect the left and right side portions on the front side of the lower part of the airbag body 40 and the front portions of the pair of front and rear extending portions 34A, respectively. By this pair of front lower tethers 58, when the inflation and deployment of the airbag body 40 (airbag 32) is completed, it is possible to suppress the inadvertent downward displacement (rotation) of the airbag body 40 around the connecting portion 34B with respect to the front and rear chambers 34.

[0058] When the inflation and deployment of the airbag 32 is completed, a pair of rear tethers 54 extend obliquely rearward downward on the lower side of the pair of front and rear extending portions 34A. That is, the pair of rear tethers 54 restrict the movement of the airbag body 40 diagonally forward and upward. Thereby, the swinging of the airbag 32 in the vertical direction and the front-rear direction can be suppressed (it can contribute to the stabilization of the deployment behavior of the airbag body 40).

[0059] In this state, as shown in FIG. 8(A), the occupant D who has moved forward by inertia due to the impact of a frontal collision of the vehicle is restrained by the airbag body 40. Specifically, as shown in FIG. 8(B), when the occupant D is restrained, the front-rear chamber 34 (front-rear extending portion 34A) is extended forward by the forward movement of the occupant D. Then, as the airbag body 40 is pressed forward by the occupant D, it is compressed and deformed forward.

[0060] Therefore, the energy absorption performance of the airbag body 40 can be improved. That is, when both the front-rear chamber 34 and the airbag body 40 receive a tensile load, the load applied from the airbag body 40 to the occupant D increases with a rising right shoulder, but the load applied to the occupant D can be reduced by the compression deformation of the airbag body 40.

[0061] Moreover, since the shape of the airbag body 40 is set so as to be sandwiched between the thigh portion F and the chest C of the occupant D from the middle to the late stage during the restraint of the occupant by the airbag 32, it can contact the upper body of the occupant D over a wide area. Thereby, the load applied from the airbag body 40 to the occupant D can be favorably reduced.

[0062] Also, since the airbag body 40 expands and deploys toward the occupant D on the rear side of the connecting portion 34B after the expansion and deployment of the front-rear chamber 34, the gap between the airbag body 40 and the occupant D becomes smaller. Thereby, since the occupant D is restrained by the airbag body 40 early, the initial restraint performance of the occupant D by the airbag body 40 can be improved.

[0063] Also, in the airbag body 40, in the state of the expansion and deployment of the front-rear chamber 34, gas from the inflater 44 is supplied through a communication hole 48 formed on the rear side of the center in the left-right direction of the connecting portion 34B. That is, the gas ejected from the inflater 44 and flowing 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 through the communication hole 48.

[0064] Therefore, the airbag body 40 can be inflated and deployed sufficiently late with respect to the front and rear chambers 34. That is, after the narrow gap between the head H of the occupant D and the ceiling 28 of the vehicle compartment has passed from the rear side to the front side due to the inflation and deployment of the front and rear chambers 34, the airbag body 40 can be easily inflated and deployed toward the rear side (see FIGS. 5 to 7). Thus, it is possible to prevent the airbag body 40 from being clogged in the narrow gap, and it is possible to suppress or prevent the occurrence of poor deployment in the airbag 32.

[0065] Also, when restraining the occupant D, the airbag body 40 is relatively drawn obliquely downward to the rear by the rear tether 54. That is, 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, and can receive and support the load applied from the occupant D to the airbag body 40 together with the front and rear chambers 34.

[0066] Also, at least the rear tether 54 on the side door side is configured to be releasable after the vehicle collision. That is, by pressing the release button of the buckle device 26, the tongue 24 provided at the other end of the rear tether 54 is easily detached (the rear tether 54 is released). Therefore, as shown in FIG. 8(C), after the vehicle collision, by releasing the rear tether 54 on the side door side, the occupant D can quickly escape from the vehicle (the getting-off performance can be improved).

[0067] Also, in the case of the first embodiment, since it is configured to include the tongue 24 provided at the other end of the rear tether 54 and the buckle device 26 to which the tongue 24 is detachable, the rear tether 54 is surely released with a simple configuration. Therefore, compared with the case where it is not configured to include the tongue 24 and the buckle device 26, after the vehicle collision, the occupant D can escape from the vehicle more quickly (the getting-off performance can be further improved).

[0068] <Second Embodiment> Next, the second embodiment will be described. Parts equivalent to those in the first embodiment are denoted by the same reference numerals, and detailed descriptions (including common operations) thereof will be omitted as appropriate.

[0069] As shown in FIG. 9, in this second embodiment, at least the rear tether 54 on the side door side is configured such that after a tensile load toward the front side acts due to restraining the occupant D, and it is pulled toward the front side, the other end portion thereof comes off from the side portion of the seat back 16 of the vehicle seat 12 (or a vehicle body not shown behind the occupant D).

[0070] Specifically, as shown in FIG. 10, guide plates 60 each having a guide groove 60A formed therein are fixed to both left and right side portions of the seat back 16. The left guide groove 60A is formed in a substantially "Z" shape in a side view, and the right guide groove (not shown) is formed in a substantially reverse "Z" shape in a side view (formed in a shape symmetrical to the left guide groove 60).

[0071] And a substantially columnar protrusion 53 that engages with and is guided by the guide groove 60A is attached to the other end portion of the rear tether 54 with the thickness direction of the rear tether 54 as the axial direction. Further, one end portion of a tension coil spring 62 as a biasing member is attached to the portion of the rear tether 54 where the protrusion 53 is attached, and the other end portion of the tension coil spring 62 is attached to the seat back 16 (or the vehicle body).

[0072] According to such a configuration, as shown in FIG. 10, after a tensile load toward the front side acts on the rear tether 54 and it is pulled toward the front side, the other end portion thereof comes off from the guide plate 60. Specifically described, as shown in FIG. 10(A), before the collision of the vehicle (normal time), the protrusion 53 is located at the lower end portion of the guide groove 60A, and in this state, it is biased (pulled) obliquely rearward upward by the tension coil spring 62. Therefore, before the collision of the vehicle (normal time), the protrusion 53 does not come off from the guide plate 60.

[0073] When the vehicle undergoes a frontal collision, as shown in FIG. 10(B), when the airbag main body 40 restrains the occupant, the rear tether 54 is pulled forward against the biasing force of the tension coil spring 62 by the occupant D who moves forward due to inertial force. Then, the protrusion 53 moves forward along the guide groove 60A. In this state, since the rear tether 54 does not come off the guide plate 60, the airbag main body 40 is relatively pulled obliquely rearward downward by the rear tether 54, and the occupant D is effectively restrained by the airbag main body 40.

[0074] After the occupant restraint is completed, since the pulling load on the rear tether 54 in the forward direction disappears, as shown in FIG. 10(C), the other end (protrusion 53) of the rear tether 54 moves obliquely rearward upward along the guide groove 60A due to the biasing force of the tension coil spring 62. Then, when the occupant D gets out of the vehicle, the occupant D manually pulls the rear tether 54 obliquely forward upward. Then, as shown in FIG. 10(D), the protrusion 53 comes out of the guide groove 60A.

[0075] Therefore, if the occupant D manually lifts the rear tether 54 in this state, the tension coil spring 62 also extends, so the occupant D can crawl under the rear tether 54 and the tension coil spring 62 from below and escape from the vehicle. Thus, in the second embodiment, the rear tether 54 can be released by a simple operation of pulling the rear tether 54 forward. Therefore, after the vehicle collision, the occupant D can quickly escape from the vehicle.

[0076] <Third Embodiment> Next, the third embodiment will be described. Note that the same reference numerals are given to the parts equivalent to those in the first and second embodiments above, and the detailed description (including the common operations) is omitted as appropriate.

[0077] In this third embodiment, the rear tether 54 is configured such that after a predetermined time has elapsed since the collision of the vehicle, the other end portion thereof detaches from the side portion (or the vehicle body) of the seat back 16. Specifically, the other end portion of the rear tether 54 is configured to detach from the side portion (or the vehicle body) of the seat back 16 when the micro gas generator 68 shown in FIG. 11 or the squib 66 shown in FIG. 12 operates.

[0078] As shown in FIG. 11(A), a cylindrical portion 55 having an axial direction perpendicular to the extending direction in a side view is integrally formed at the rear end portion of the rear tether 54. Further, a detachment device 70 is fixed to the side portion of the seat back 16. The detachment device 70 includes a main body portion 72 having a micro gas generator 68 incorporated therein on the upper surface side, a support portion 74 having a substantially reverse “L” shape in a side view extending upward from the rear end portion on the upper surface of the main body portion 72, and a cylindrical pin 76.

[0079] The pin 76 is formed slightly longer than the length of the support portion 74, and its base portion (upper end portion) 76A is rotatably supported at the upper front end of the support portion 74 with the vehicle width direction as the axial direction. Then, this pin 76 is inserted into the cylindrical portion 55 of the rear tether 54, and its tip portion (lower end portion) 76B is detachably attached to the upper surface of the main body portion 72.

[0080] That is, as shown in FIG. 11(B), when the micro gas generator 68 operates, the attachment state of the tip portion 76B of the pin 76 to the upper surface of the main body portion 72 is released, and the tip portion 76B of the pin 76 is configured to be pushed forward by the pressure of the gas. When the rear tether 54 is pulled forward in this state, the tip portion 76B of the pin 76 rotates forward about the base portion 76A, and the pin 76 comes off from the cylindrical portion 55. That is, the other end portion of the rear tether 54 is configured to detach from the side portion of the seat back 16.

[0081] Further, as shown in FIG. 12(A), a detachment device 64 provided with a squib 66 may be fixed to the side portion of the seat back 16. The detachment device 64 has the squib 66 built in on its upper surface side, and the other end of the rear tether 54 is fixed to the side portion of the seat back 16. A part 54C of the rear tether 54 that faces the squib 66 in the vertical direction and is close to it is formed to be narrower in width than other parts. Therefore, as shown in FIG. 12(B), when the squib 66 operates, a part 54C of the rear tether 54 is burned through. That is, the other end of the rear tether 54 is disengaged from the side portion of the seat back 16.

[0082] Thus, according to the third embodiment, without the occupant D having to perform a special operation, after a predetermined time has elapsed since the collision of the vehicle, the other end of the rear tether 54 is automatically disengaged from the side portion of the seat back 16 (the rear tether 54 is released). Therefore, after the collision of the vehicle, the occupant D can quickly escape from the vehicle. Here, the "after a predetermined time has elapsed" means after the time when the amount of movement of the occupant D forward has reached the maximum.

[0083] Also, according to this third embodiment, when the micro gas generator 68 or the squib 66 operates, the other end of the rear tether 54 is disengaged. That is, with a simple mechanism, the other end of the rear tether 54 is quickly disengaged from the side portion of the seat back 16 (the rear tether 54 is quickly released). Therefore, after the collision of the vehicle, the occupant D can escape from the vehicle more quickly.

[0084] <Fourth Embodiment> Finally, the fourth embodiment will be described. Note that the same reference numerals are given to parts equivalent to those in the first to third embodiments above, and detailed descriptions (including common operations) are omitted as appropriate.

[0085] As shown in FIG. 13, in this fourth embodiment, the rear tether 54 is provided only on the non-shoulder belt side of the seat belt device 20 (the side where the seat belt 22 is not worn on the shoulder K). That is, the rear tether 54 is not provided on the shoulder belt side of the seat belt device 20 (the side where the seat belt 22 is worn on the shoulder K). Usually, the shoulder belt side of the seat belt device 20 is the side door side. Therefore, after a vehicle collision, there is no rear tether 54 on the side door side which is the escape side, so there is no problem that the rear tether 54 gets in the way, and the occupant D can quickly escape outside the vehicle.

[0086] Also, since the rear tether 54 is not provided on the shoulder belt side of the seat belt device 20, the shoulder belt (seat belt 22) and the rear tether 54 do not get caught (entangled) with each other. Note that the occupant D sitting on the vehicle seat 12 has the outer shoulder K and chest C in the vehicle width direction restrained by the shoulder belt, and a restraining force is already acting on the outer shoulder K in the vehicle width direction. Therefore, even if the rear tether 54 on the outer side (side door side) in the vehicle width direction is abolished, the occupant restraint performance during a frontal collision of the vehicle can be ensured.

[0087] As described above, the airbag device 30 and the occupant protection device 10 according to the present embodiment have been described based on the drawings. However, the airbag device 30 and the occupant protection device 10 according to the present embodiment are not limited to those shown in the drawings, and can be appropriately designed and changed within the scope not departing from the gist of the present invention.

[0088] For example, each one end portion of the pair of rear tethers 54 may be sewn and attached not to the left and right wall surfaces on the lower front side that expands and deploys below the front and rear chambers 34 in the airbag body 40, but to the longitudinal middle portion of the pair of front and rear extending portions 34A, specifically, the front portion (front side portion) of each expanded and deployed front and rear extending portion 34A.

Explanation of Reference Numerals

[0089] 10 Occupant protection device 12 Vehicle seat 16 seat back 20 seat belt device 24 tongue 26 buckle device 30 airbag device 32 airbag 34 front and rear chambers 40 airbag body 44 inflater 54 rear tether 66 squib 68 micro gas generator

Claims

1. An inflator that generates gas upon collision of the vehicle, an airbag to which the gas generated by the inflator is supplied and that expands and deploys from the rear side of the vehicle seat through the upper side of the seat to the front side of the seat, and the airbag in the inflated and deployed state has a pair of front-rear chambers that extend in the front-rear direction of the seat passing through both the left and right sides of the head of an occupant seated on the vehicle seat, an airbag body that communicates with the pair of front-rear chambers and is disposed on the front side of the occupant between the pair of front-rear chambers, and a pair of rear tethers having one end attached to the airbag body or the front-side portion of the pair of front-rear chambers of the vehicle seat and the other end attached to the seat back or the vehicle body of the vehicle seat, and an airbag device in which at least the rear tether on the side door side is configured such that after a predetermined time has elapsed from the collision of the vehicle, the other end comes off from the seat back or the vehicle body of the vehicle seat.

2. The airbag device according to claim 1, wherein the other end of the rear tether is configured to come off by the operation of a squib or a micro gas generator.

3. A vehicle seat on which an occupant is seated, and the airbag device according to claim 1 or claim 2 mounted on a portion on the rear side of the seat of the vehicle seat, and an occupant protection device comprising the same.

4. An inflator that generates gas upon collision of the vehicle, an airbag to which the gas generated by the inflator is supplied and that expands and deploys from the rear side of the vehicle seat through the upper side of the seat to the front side of the seat, a three-point seat belt device for restraining an occupant on the vehicle seat, and the airbag in the inflated and deployed state has a pair of front-rear chambers that extend in the front-rear direction of the seat passing through both the left and right sides of the head of the occupant seated on the vehicle seat, an airbag body that communicates with the pair of front-rear chambers and is disposed on the front side of the occupant between the pair of front-rear chambers, and a rear tether having one end attached to the airbag body or the front-side portion of the pair of front-rear chambers of the vehicle seat and the other end attached to the seat back or the vehicle body of the vehicle seat, and the rear tether is provided only on the non-shoulder belt side of the seat belt device, An occupant protection device configured such that after a predetermined time has elapsed since the collision of the vehicle, the other end portion comes off from the seat back or the vehicle body of the vehicle seat.

Images