Vehicle airbag systems and occupant protection devices

Abstract

To provide a vehicle airbag device and an occupant protection apparatus comprising the same, capable of achieving both easy deployment of an airbag and occupant restraint stability.SOLUTION: A vehicle airbag device 30 comprises: an airbag 32 which is inflated and deployed from a seat rear side of a vehicle seat 12 toward a seat front side thereof; and a pair of left and right rear tethers 54 connecting the airbag 32 to a seatback 16 of the vehicle seat 12 or to a vehicle body. The airbag 32 comprises: a pair of left and right front-rear extension parts 34A which are inflated and deployed toward the seat front side through both left and right sides of a head H of an occupant D; a connection part 34B connecting front end parts of the pair of front-rear extension parts 34A in a seat left-right direction; and an airbag body 40 which is inflated and deployed at a seat rear side of the connection part 34B toward the occupant D side later than a front-rear chamber 34. During occupant restraint, the pair of rear tethers 54 pulls the pair of respective left and right front-rear extension parts 34A relatively toward the seat rear side and obliquely downward to bring the connection part 34B close to a thigh part F of the occupant D.SELECTED DRAWING: Figure 11

Description

Technical Field

[0001] The present invention relates to a vehicle airbag device and an occupant protection device.

Background Art

[0002] Patent Document 1 below discloses an airbag device including an inflater that generates high-pressure gas upon impact input, and a bag body (airbag) that expands and deploys from a 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 from behind the head of a seated occupant toward the front of the occupant, and a pair of head support portions that deploy on both left and right sides of the occupant's head and connect to the body support portion. In the technique described in Patent Document 1 below, the deployed body support portion is connected to the seat or the vehicle body by a belt-like connecting member. As a result, the deployed body support portion is restricted from moving by the connecting member.

[0003] Further, Patent Document 2 below discloses an airbag device including an inflater and an airbag that deploys 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 left and right sides of the rear inflation portion, and a pair of front inflation portions that extend from the side inflation portions toward the center side and are connected to each other at the center to cover the front of the occupant. Furthermore, the airbag device described in Patent Document 2 below includes a belt-like connecting member that connects a pair of support points provided on the front side of the seat and on both left and right sides of the seat to the side 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 technologies described in Patent Documents 1 and 2 above, the airbag is configured to deploy from behind the occupant's head to the front of the head. If the connecting member is short, there is a risk that the airbag will be pulled downwards towards the seat during deployment and will not be able to pass between the occupant's head and the vehicle's roof. Conversely, if the connecting member is long, while the airbag will pass over the occupant's head more easily during deployment, there is a risk that the airbag body will lift up during occupant restraint, reducing the contact area between the occupant and the airbag, and that the airbag may escape upwards above the occupant's head. In other words, there is room for improvement in achieving both ease of airbag deployment and stable occupant restraint.

[0006] In consideration of the above facts, the present invention aims to provide a vehicle airbag system and an occupant protection device equipped therewith that can achieve both ease of airbag deployment and stable occupant restraint. [Means for solving the problem]

[0007] The first embodiment of the vehicle airbag system comprises an inflator that generates gas in the event of a vehicle collision, an airbag to which the gas is supplied and which inflates and deploys from the rear side of the upper part of the vehicle seat toward the front side of the seat, and a pair of left and right rear tethers that connect the airbag to the seat back of the vehicle seat or the vehicle body, wherein the airbag is configured to include a pair of left and right front-rear extending portions that inflate and deploy toward the front side of the seat, passing on both sides of the head of an occupant seated in the vehicle seat, and a connecting portion that connects the front ends of the pair of left and right front-rear extending portions in the left-right direction of the seat when inflation and deployment are complete. The system comprises a chamber and an airbag body that inflates and deploys toward the occupant at the rear side of the connecting portion of the seat, lagging behind the front and rear chambers, and restrains the occupant. When the occupant is restrained, the front and rear extensions extend in the front-rear direction of the seat, while the airbag body is compressed so as to be sandwiched between the occupant's thighs and chest. The pair of left and right rear tethers are each secured at one end to the pair of left and right front and rear extensions, and at the other end to the seat back or the vehicle body. When the occupant is restrained, the pair of left and right front and rear extensions are each relatively pulled diagonally downward and rearward toward the rear of the seat, bringing the connecting portion closer to the occupant's thighs.

[0008] According to the first embodiment of the vehicle airbag system, gas generated from the inflator is supplied to the airbag during a vehicle collision, and the airbag inflates and deploys from the rear side of the vehicle seat towards the front side. At this time, the pair of front-to-rear extensions in the front-to-rear chambers inflate and deploy towards the front of the seat, passing on both sides of the head of the occupant seated in the vehicle seat. The airbag body also inflates and deploys toward the occupant at the rear side of the connecting section, lagging behind the front-to-rear chambers. When the occupant is restrained, the airbag body is compressed so as to be sandwiched between the occupant's thighs and chest, while the front-to-rear extensions extend in the front-to-rear direction of the seat. This compressive deformation of the airbag body absorbs the kinetic energy of the occupant's inertial movement. The pair of front-to-rear extensions also serve as gas passages and support the load applied to the airbag body by the occupant. However, the term "pulling diagonally downward and rearward" as used here broadly includes the concept of applying a load diagonally downward and rearward to the pair of front-to-rear extending portions on the left and right sides of the seat in order to prevent the airbag itself from lifting up.

[0009] Here, the airbag is connected to the seatback or vehicle body by a pair of rear tethers on the left and right sides. More specifically, one end of each rear tether is secured to a pair of front-to-rear extensions on the left and right sides, and the other end is secured to the seatback or vehicle body. The pair of rear tethers, together with the front and rear chambers, receive and support the load applied to the airbag body by the occupant. Furthermore, when the occupant is restrained by the airbag, the pair of front-to-rear extensions on the left and right sides are relatively pulled in diagonally downward and rear of the seat by the pair of rear tethers, and the connection point approaches the occupant's thigh. At this time, the airbag body, which has inflated and deployed on the rear side of the seat at the connection point, rotates so as to tilt forward of the seat. As a result, the airbag body fits deeply between the occupant's thigh and chest, increasing the contact area between the occupant and the airbag. This suppresses the lifting of the airbag body.

[0010] In the second embodiment of the vehicle airbag system, the seat back or the vehicle body is provided with a pair of left and right pretensioner mechanisms that retract the left and right pair of rear tethers after the airbag has finished inflating and deploying.

[0011] According to the vehicle airbag system of the second embodiment, after the airbag has finished inflating and deploying, a pair of left and right pretensioner mechanisms provided on the seat back or vehicle body are activated, and a pair of left and right rear tethers are retracted. The pair of left and right front-to-rear extensions are strongly retracted diagonally downward and rear of the seat by the pair of left and right pretensioner mechanisms. In other words, the length of the pair of left and right rear tethers when the occupant is restrained by the airbag is shorter than the length of the pair of left and right rear tethers when the airbag is inflated and deployed. This makes it possible to set a longer maximum length for the rear tether when the airbag is inflated and deployed. Thus, it is possible to make it easier for the airbag to pass through the narrow gap above the occupant's head, while reliably preventing the airbag body from lifting up when the occupant is restrained.

[0012] In the third embodiment of the vehicle airbag system, the pair of left and right pretensioner mechanisms are provided symmetrically on both the left and right sides of the seat back, as in the second embodiment.

[0013] According to the third embodiment of the vehicle airbag system, a pair of left and right rear tethers are retracted by a pair of symmetrically arranged pretensioner mechanisms, thereby effectively and balancedly suppressing the vertical and longitudinal movement of the airbag when inflation and deployment are complete.

[0014] In the fourth embodiment of the vehicle airbag device, in the first embodiment, the longitudinal elongation rate of the pair of left and right rear tethers is smaller than the longitudinal elongation rate of the pair of left and right front and rear extending portions.

[0015] According to the fourth embodiment of the vehicle airbag device, when the airbag inflates and deploys, a pair of left and right front-to-rear extensions are primarily subjected to tensile load and extend. When the occupant is restrained by the airbag, the tensile load is distributed by the pair of left and right front-to-rear extensions and a pair of left and right rear tethers that are less stretchable, supporting the airbag body. The easily stretchable pair of left and right front-to-rear extensions extend further in the longitudinal direction as the occupant's upper body leans forward towards the seat. Here, the less stretchable pair of left and right rear tethers apply a load to the pair of left and right front-to-rear extensions diagonally downward and rear of the seat. As a result, the airbag body rotates so as to lean forward towards the seat, deforming into a wedge shape when viewed from the side of the seat. As a result, the contact area between the occupant's thighs and the connection point of the airbag increases even further, suppressing the lifting of the airbag body. Therefore, with a simple configuration, the airbag can easily pass through the narrow gap above the occupant's head while suppressing the lifting of the airbag body.

[0016] In the fifth embodiment of the vehicle airbag system, in the fourth embodiment, the pair of left and right rear tethers are made of a material that is less stretchable than the pair of left and right front-to-rear extending portions.

[0017] According to the fifth embodiment of the vehicle airbag device, the difference in the elongation rate of the material itself allows the elongation rate in the longitudinal direction of the pair of left and right rear tethers to be smaller than the elongation rate in the longitudinal direction of the pair of left and right front and rear extending portions. Therefore, with an even simpler configuration, the airbag can easily pass through the narrow gap above the occupant's head while preventing the airbag body from lifting.

[0018] In the sixth embodiment of the vehicle airbag device, in the fourth embodiment, the pair of left and right rear tethers have a weave parallel to the longitudinal direction, and the pair of left and right front and rear extending portions have a weave oblique to the longitudinal direction.

[0019] According to the vehicle airbag device of the sixth embodiment, the difference in the direction of the fabric weave allows the longitudinal elongation rate of the pair of left and right rear tethers to be smaller than the longitudinal elongation rate of the pair of left and right front and rear extending portions. Therefore, with an even simpler configuration, the airbag can easily pass through the narrow gap above the occupant's head while preventing the airbag body from lifting.

[0020] In the seventh embodiment of the vehicle airbag system, in the fourth embodiment, the pair of left and right rear tethers are provided with reinforcing stitching portions that are sewn along the longitudinal direction in at least part of the portion.

[0021] According to the vehicle airbag device of the seventh embodiment, at least a portion of the reinforcing stitching is sewn along the longitudinal direction of the pair of left and right rear tethers, thereby suppressing the longitudinal extension of the pair of left and right rear tethers. Therefore, it has the excellent effect of being able to easily pass the airbag through the narrow gap above the occupant's head while suppressing the lifting of the airbag body, with an even simpler configuration.

[0022] In the eighth embodiment of the vehicle airbag system, the reinforcing stitching portion is provided continuously in the longitudinal direction of the pair of left and right rear tethers, as in the seventh embodiment.

[0023] According to the vehicle airbag device of the eighth aspect, since the reinforcing sewing part is continuously provided in the longitudinal direction of the pair of left and right rear tethers, the elongation of the pair of left and right rear tethers in the longitudinal direction is more effectively suppressed.

[0024] The vehicle airbag device of the ninth aspect is, in the seventh aspect, a plurality of the reinforcing sewing parts are provided at intervals in the longitudinal direction of the pair of left and right rear tethers.

[0025] According to the vehicle airbag device of the ninth aspect, in the pair of left and right rear tethers, portions where the reinforcing sewing part is provided and portions where the reinforcing sewing part is not provided are alternately arranged along the longitudinal direction. Thereby, it becomes easy to fold the pair of left and right rear tethers, and the airbag can be stored compactly.

[0026] The vehicle airbag device of the tenth aspect is, in the first aspect, when the airbag body at the completion of inflation and deployment faces the head, chest, and abdomen of the occupant with a gap from the front side.

[0027] According to the vehicle airbag device of the tenth aspect, the airbag body is inflated and deployed without interfering with the head, chest, and abdomen of the occupant. On the other hand, when restraining the occupant, since the airbag body can bring the upper body including the head, chest, and abdomen of the occupant into contact with the airbag body over a large area, the load applied from the airbag body to the occupant can be reduced well.

[0028] The vehicle airbag device of the eleventh aspect is, in the tenth aspect, configured such that the lower surfaces of the pair of left and right front and rear extending parts contact the left and right shoulders of the occupant when restraining the occupant.

[0029] According to the 11th embodiment of the vehicle airbag system, when the occupant is restrained by the airbag, the pair of front-to-rear extensions on the left and right sides are pulled diagonally downward and rearward from the seat by the pair of rear tethers on the left and right sides, so that the lower surfaces of the pair of front-to-rear extensions on the left and right sides come into contact with the left and right shoulders of the occupant. This makes it possible to stabilize the vertical position of the airbag body relative to the occupant's head on the seat, regardless of the occupant's physique.

[0030] In the twelfth embodiment of the vehicle airbag system, in the first embodiment, each end of the pair of left and right rear tethers is connected to the front of the pair of left and right front extensions at a position that overlaps with the airbag body when inflation and deployment are complete, as viewed from the side of the seat.

[0031] According to the vehicle airbag device of the 12th embodiment, the left and right rear tethers are connected to the front of the left and right front-to-rear extensions at a position that overlaps with the airbag body when it is fully inflated and deployed when viewed from the side of the seat, so that the connecting portion can be brought closer to the occupant's thigh.

[0032] In the 13th embodiment of the vehicle airbag device, in the first embodiment, the pair of left and right front and rear chambers are formed into a bag shape by sewing the periphery portions of two overlapping base fabrics at a sewing section, and the pair of left and right rear tethers are sewn to the pair of left and right front and rear extensions at a part of the sewing section.

[0033] According to the vehicle airbag device of the 13th embodiment, the left and right pair of rear tethers are sewn to the peripheral stitching portion of the left and right pair of front and rear extension portions. Therefore, compared to the case in which the left and right pair of rear tethers are sewn to the left and right pair of front and rear extension portions at a position other than the peripheral stitching portion, the left and right pair of rear tethers can be secured to the left and right pair of front and rear extension portions with a simpler configuration, while maintaining the strength of the airbag.

[0034] In the 14th embodiment of the vehicle airbag device, in the 13th embodiment, the pair of left and right rear tethers are sewn together with the reinforcing fabric to the two base fabrics of the pair of left and right front and rear extending portions at the peripheral seam.

[0035] According to the 14th embodiment of the vehicle airbag device, the strength of the portion where the left and right pair of rear tethers are sewn to the left and right pair of front and rear extensions can be improved by the reinforcing fabric.

[0036] The occupant protection device of the 15th embodiment comprises a vehicle seat on which an occupant sits, and a vehicle airbag device according to any one of the 1st to 14th embodiments mounted on the rear side of the upper part of the vehicle seat.

[0037] According to the occupant protection device of the 15th embodiment, gas generated from an inflator is supplied to the airbag during a vehicle collision, causing the airbag to inflate and deploy from the rear side of the vehicle seat towards the front side. At this time, the pair of front-to-rear extensions in the front-to-rear chambers inflate and deploy towards the front of the seat, passing on both sides of the occupant's head while seated in the vehicle seat. The airbag body also inflates and deploys toward the occupant at the rear side of the connecting section, lagging behind the front-to-rear chambers. When the occupant is restrained, the airbag body is compressed so as to be sandwiched between the occupant's thighs and chest, while extending its front-to-rear extensions in the front-to-rear direction of the seat. This compressive deformation of the airbag body absorbs the kinetic energy of the occupant's inertial movement. The pair of front-to-rear extensions also serve as gas passages and support the load applied to the airbag body by the occupant.

[0038] Here, the pair of rear tethers on the left and right sides, along with the front and rear chambers, support the load applied to the airbag body by the occupant. Furthermore, when the occupant is restrained by the airbag, the pair of front and rear extensions on the left and right sides are pulled diagonally downward and behind the seat by the pair of rear tethers, and the connecting part moves closer to the occupant's thigh. This increases the contact area between the occupant and the airbag, suppressing the airbag from lifting up. [Effects of the Invention]

[0039] As described above, the vehicle airbag system of the first embodiment has the excellent effect of achieving both ease of airbag deployment and stable restraint of the occupant.

[0040] The vehicle airbag system of the second embodiment has the excellent effect of making it even easier for the airbag to pass through the narrow gap above the occupant's head, while reliably preventing the airbag body from lifting up when the occupant is restrained.

[0041] The vehicle airbag system of the third embodiment has the excellent effect of being able to effectively and evenly suppress the oscillation of the airbag in the vertical and longitudinal directions of the seat when inflation and deployment are complete.

[0042] The vehicle airbag systems of the 4th to 7th embodiments have a simple configuration and offer the excellent advantage of achieving both ease of airbag deployment and stable occupant restraint.

[0043] The eighth embodiment of the vehicle airbag system has the excellent effect of being able to more effectively suppress the longitudinal extension of the pair of left and right rear tethers.

[0044] The vehicle airbag system of the ninth embodiment has the excellent effect of being able to house the airbag compactly.

[0045] The tenth embodiment of the vehicle airbag system has the excellent effect of suppressing interference between the airbag body and the occupant's head, chest, and abdomen during inflation and deployment, while effectively reducing the load applied to the occupant from the airbag body during occupant restraint.

[0046] The vehicle airbag system of the 11th embodiment has the excellent effect of being able to stabilize the vertical position of the airbag body relative to the occupant's head on the seat, regardless of differences in the occupant's physique.

[0047] The vehicle airbag device of the twelfth embodiment has the excellent effect of being able to effectively bring the connecting portion closer to the occupant's thigh.

[0048] The vehicle airbag device of the 13th embodiment has the excellent effect of being able to secure a pair of left and right rear tethers to a pair of left and right front and rear extending portions with a simple configuration, while maintaining the strength of the airbag.

[0049] The vehicle airbag system of the 14th embodiment has the excellent effect of being able to improve the strength of the airbag.

[0050] The occupant protection device of the 15th embodiment has the excellent effect of being able to achieve both ease of deployment of an airbag mounted on a vehicle seat and restraint stability for an occupant seated in the vehicle seat. [Brief explanation of the drawing]

[0051] [Figure 1] This is a perspective view showing the occupant protection device according to the first embodiment in a state where the airbag has been inflated and deployed. [Figure 2] This is a side view showing the configuration shown in Figure 1, viewed from the left side of the vehicle. [Figure 3] Figure 1 is a plan view showing the configuration as seen from above the vehicle. [Figure 4] Figure 1 is a front view showing the configuration as seen from the front of the vehicle. [Figure 5] Figure 4 is a front view showing the airbag as seen through the glass. [Figure 6] Figure 1 is an exploded view of the front and rear chambers. [Figure 7] Figure 1 is an exploded view of the airbag body. [Figure 8] This is an enlarged cross-sectional view taken along line 8-8 in Figure 2. [Figure 9] Figure 1 is a side cross-sectional view of the upper part of the seatback, showing the state before the airbag inflates and deploys. [Figure 10] Figure 1 is a side cross-sectional view of the upper part of the seatback, showing the state immediately after the airbag has finished inflating and deploying. [Figure 11] This is a side view showing the state immediately after the airbag in Figure 1 has finished inflating and deploying. [Figure 12] Figure 1 is a side view showing the initial state of occupant restraint by the airbag. [Figure 13] Figure 1 is a side view showing the state of occupant restraint in the later stages of the airbag system. [Figure 14] This is a side cross-sectional view of the area around the upper part of the seatback, showing the state immediately after the airbag inflation and deployment have been completed in an occupant protection device according to a first modification of the first embodiment. [Figure 15] This is a side cross-sectional view of the area around the upper part of the seatback, showing the state immediately after the airbag inflation and deployment have been completed in an occupant protection device according to a second modification of the first embodiment. [Figure 16] This is a side view showing the occupant protection device according to the second embodiment, with the airbag inflated and deployed, as viewed from the left side of the vehicle. [Figure 17] Figure 16 is a side cross-sectional view of the upper part of the seatback, showing the state of the airbag before it inflates and deploys. [Figure 18] Figure 16 is an exploded view of the front and rear chambers. [Figure 19] This is an enlarged cross-sectional view taken along line 19-19 in Figure 16. [Figure 20] This diagram illustrates the reinforcing stitching of the rear tether shown in Figure 16. [Figure 21A] This figure illustrates the direction of the fabric weave in the front-to-back extending portion shown in Figure 16. [Figure 21B] This figure shows the state in which the front and rear extensions shown in Figure 21A are stretched. [Figure 22A] This diagram illustrates the direction of the fabric weave of the rear tether shown in Figure 16. [Figure 22B] Figure 20A shows the rear tether in the extended position. [Figure 23] Figure 16 is a side view showing the state immediately after the airbag has finished inflating and deploying. [Figure 24] Figure 16 is a side view showing the initial state of occupant restraint by the airbag. [Figure 25]Figure 16 is a side view showing the state of occupant restraint in the later stages of the airbag system. [Figure 26] This figure illustrates the reinforcing stitching portion of the rear tether in the occupant protection device according to the first modified example of the second embodiment. [Figure 27] This figure illustrates the reinforcing stitching portion of the rear tether in a occupant protection device according to a second modified example of the second embodiment. [Figure 28] This figure illustrates the reinforcing stitching portion of the rear tether in a third modified example of the second embodiment of the occupant protection device. [Figure 29] This is a cross-sectional view corresponding to Figure 19, showing the occupant protection device according to the fourth modified example of the second embodiment, in a state where the airbag has completed inflation and deployment. [Figure 30] This diagram illustrates the reinforcing stitching of the rear tether shown in Figure 28. [Figure 31] This figure illustrates the reinforcing stitching portion of the rear tether in a fifth modified example of the second embodiment of the occupant protection device. [Modes for carrying out the invention]

[0052] <First Embodiment> The occupant protection device 10 according to the first embodiment of the present invention will be described below with reference to Figures 1 to 13. In each figure, some reference numerals may be omitted for clarity. The arrows FR, UP, LH, and RH indicated in each figure as appropriate represent the forward (direction of travel), upward, left, and right directions of the vehicle, respectively. Hereafter, when simply referring to the front / rear, left / right, and up / down directions, unless otherwise specified, they refer to the front / rear direction of the vehicle, the left / right direction of the vehicle, and the up / down direction of the vehicle.

[0053] As shown in Figures 1-5, the occupant protection device 10 consists of a vehicle seat 12 and an airbag device 30. The vehicle seat 12 is either a front seat or a rear seat of a vehicle (automobile). This vehicle seat 12 has a seat cushion 14, a seat back 16 erected above the rear end of the seat cushion 14, and a headrest 18 connected to the upper end of the seat back 16. The front-rear, left-right, up-down directions of this vehicle seat 12 coincide with the front-rear, left-right, up-down directions of the vehicle.

[0054] Figures 1 to 5 illustrate a crash test dummy D, representing a model of the occupant (seater) to be protected, seated on the seat cushion 14 of the vehicle seat 12. Dummy D is, for example, an AM50 (50th percentile of an American adult male) dummy (Hybrid III) used for frontal crash tests. Dummy D is seated in the standard seating position defined by the crash test method, and the vehicle seat 12 is positioned at the standard setting position corresponding to that seating position. Hereafter, for the sake of clarity, dummy D will be referred to as "occupant D".

[0055] 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 (see Figures 1 to 3; not shown in Figures 4 and 5) provided by the seat belt device 20. The seat belt device 20 is a three-point seat belt device, and is a so-called seat belt device with a seat, in which a retractor, anchor and buckle (not shown) are provided on the vehicle seat 12.

[0056] As shown in Figure 9, the airbag device 30 comprises an airbag 32, a pair of inflators 44, and a module case 46. The airbag 32 is normally folded and stored in the module case 46 together with the pair of inflators 44. The module case 46 is formed in a hollow rectangular parallelepiped shape. This module case 46 is located at the rear of the upper part of the vehicle seat 12 (more specifically, at the upper end of the seat back 16 and behind the headrest 18) and is fixed to the upper end of the seat back 16 or to the vehicle body (not shown).

[0057] The airbag 32 receives gas from a pair of inflators 44 and inflates and deploys (deploys and inflates) from the rear to the front of the upper part of the vehicle seat 12. The airbag 32 has front and rear chambers 34 and an airbag body 40. The front and rear chambers 34 have a pair of front and rear extending portions 34A that inflate and deploy forward, passing on both sides of the occupant D's head H, and a connecting portion 34B that connects the front ends of the pair of front and rear extending portions 34A in the left-right direction. The airbag body 40 inflates and deploys toward the occupant D (rear side) behind the front and rear chambers 34 at the rear side of the connecting portion 34B.

[0058] The front and rear chambers 34 are formed into a long bag shape by overlapping two long base fabrics 36 and 38 shown in Figure 6 and sewing the periphery at the sewing section S1. The airbag body 40 is formed into a bag shape by folding a single base fabric 42 shown in Figure 7 along four fold lines L1, L2, L3, and L4 and sewing it at the sewing section S2. At this sewing section S2, sewing lines SL21 and SL22 are sewn, sewing lines SL23 and SL24 are sewn, sewing lines SL25 and SL26 are sewn, and sewing lines SL27 and SL28 are sewn. The base fabrics 36, 38, and 42 shown in Figures 6 and 7 are made of, for example, nylon or polyester fabric. One or both of the two base fabrics 36 and 38 that make up the front and rear chambers 34 are made of a base fabric that is less stretchable than the base fabric 42 that makes up the airbag body 40.

[0059] As shown in Figure 6, the longitudinal ends of the front and rear chambers 34 are a pair of left and right inflator housings 34C that house a pair of inflators 44. The longitudinal center of the front and rear chambers 34 is a connecting section 34B, and the area between the connecting section 34B and the pair of inflator housings 34C is a front and rear extension section 34A. As shown in Figures 6 and 8, the pair of front and rear extension sections 34A are each formed in a long tubular shape.

[0060] As shown in Figure 6, the connecting portion 34B is a roughly T-shaped bag that communicates with each of the front and rear extending portions 34A. The connecting portion 34B is sewn to the airbag body 40 at a sewing portion S3 (see Figures 6 and 7) located in the center of the connecting portion 34B. The sewing portion S3 is, for example, roughly trapezoidal in shape. A communication hole 48 is formed on the inside of the sewing portion S3, connecting the inside of the connecting portion 34B and the inside of the airbag body 40. The communication hole 48 is, for example, roughly trapezoidal in shape. This communication hole 48 is composed of a through hole 50 formed in the base fabric 36 of the front and rear chambers 34 and a through hole 52 formed in the base fabric 42 of the airbag body 40.

[0061] The pair of inflators 44 are combustion-type or cold-gas-type cylinder inflators that generate gas when activated. These inflators 44 are controlled by a control device (not shown) to generate gas in the event of a vehicle collision.

[0062] Figure 9 shows a side cross-sectional view of the upper part of the seat back 16 before the airbag 32 inflates and deploys. A pair of inflator housings 34C (see Figure 6), each housing a pair of inflators 44, are arranged separately on the left and right sides within the module case 46. Each inflator 44 is positioned so that its axial direction is aligned with 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 the frame of the inflator housing 34C, the module case 46, and the seat back 16, and nuts are screwed onto each stud bolt. In this way, the inflator housing 34C, the inflators 44, and the module case 46 are fixed to the frame of the seat back 16.

[0063] The airbag 32 is normally folded in a predetermined way, such as a roll fold or accordion fold, and housed in the module case 46. When the pair of inflators 44 are activated, gas is generated in the pair of inflator housings 34C.

[0064] As shown in Figures 10 and 11, the gas generated in the pair of inflator housings 34C flows through the pair of front and rear extensions 34A towards the connecting section 34B and is supplied into the airbag body 40 through the communication hole 48. As a result, the airbag 32 inflates and deploys in the order of the pair of front and rear extensions 34A, the connecting section 34B, and the airbag body 40. When the airbag 32 inflates and deploys, a tear line (not shown) formed in the module case 46 is configured to rupture in response to the inflation pressure of the airbag 32. This allows the airbag 32 to inflate and deploy to the outside of the module case 46. As shown in Figure 10, when the pair of front and rear extensions 34A inflate and deploy, the folded airbag body 40 and connecting section 34B pass between the occupant D's head H and the vehicle roof (not shown).

[0065] As shown in Figure 11, the inflated and deployed pair of front-to-rear extensions 34A extend in the front-to-rear direction on both the left and right sides of the occupant D's head H, facing the head H from both sides with a gap between them. The pair of front-to-rear extensions 34A are pulled diagonally downward and rearward by a pair of rear tethers 54, which will be described later, so that they are inclined to slope downward toward the front. The front ends of the inflated and deployed pair of front-to-rear extensions 34A are connected in the left-to-right direction by an inflated and deployed connecting part 34B. As shown in Figure 3, the front-to-rear chamber 34, including the pair of front-to-rear extensions 34A and the connecting part 34B, inflates and deploys in a U-shape that opens rearward in a plan view.

[0066] As shown in Figures 1, 2, 4, and 5, an enlarged portion 34B1 is provided at the left-right center of the inflated and deployed connecting portion 34B, with a vertical dimension greater than that of the left and right ends of the connecting portion 34B. This enlarged portion 34B1 protrudes downward from the left and right ends of the connecting portion 34B. The aforementioned communication hole 48 (see Figure 6) is formed in this enlarged portion 34B1. This communication hole 48 is located on the rear side of the left-right center of the inflated and deployed connecting portion 34B. Gas from the inflator 44 is supplied to the airbag body 40 in a rearward direction through the communication hole 48. As a result, the airbag body 40 inflates and deploys towards the occupant D side (rear side) behind the front and rear chambers 34 after the front and rear chambers 34 have inflated and deployed. The inflated and deployed airbag unit 40 faces the occupant D's head H, chest C, and abdomen B from the front, leaving a gap between them.

[0067] As shown in Figures 11 to 13, the inflated and deployed airbag body 40 restrains the occupant D, who is inertially moving forward due to the impact of a vehicle collision, from the front. During this occupant restraint, the front and rear chambers 34 are extended in the front-rear direction, and the airbag body 40 is compressed in the front-rear direction. As shown in Figures 12 and 13, the shape of the airbag body 40 is set so that it is sandwiched between the thighs F and chest C of the occupant D during occupant restraint.

[0068] As shown in Figures 1 to 4, the airbag 32 is fitted with a pair of rear tethers 54, a pair of front upper tethers 56, and a pair of front lower tethers 58. The rear tethers 54, front upper tethers 56, and front lower tethers 58 are made of, for example, nylon or polyester fabric in the shape of long strips.

[0069] Each end of the pair of rear tethers 54 is secured to the longitudinal middle portion of the pair of front and rear extensions 34A. More specifically, as shown in Figures 2 and 8, each end of the pair of rear tethers 54 is sewn together with the reinforcing fabric 62 to the front of the pair of front and rear extensions 34A in a part of the sewing section S1 at a position that overlaps with the airbag body when inflation and deployment are complete in a side view of the seat. Note that the airbag 32 does not necessarily have to be equipped with the reinforcing fabric 62. Also, the airbag 32 may be equipped with multiple reinforcing fabrics. Furthermore, for example, each end of the pair of rear tethers 54 may be sewn to an extension that is wider than the other seam allowances of the front and rear chambers 34.

[0070] As shown in Figure 11, the seat back 16 is provided with a pair of pretensioner mechanisms 64. The pair of pretensioner mechanisms 64 are provided symmetrically on both the left and right sides of the seat back 16. The other ends of the pair of rear tethers 54 are locked to the pretensioner mechanisms 64 on the seat back 16. The pretensioner mechanism includes, as an example, a spool (not shown) for winding up the rear tether 54. However, the pretensioner mechanism is not limited to this and may include, for example, a cylinder and a piston that moves inside the cylinder.

[0071] As shown in Figures 1, 9, and 10, the seat back 16 has a pair of left and right slits 16A that extend in the vertical direction of the seat. The pair of slits 16A are located on both sides of the seat in the left-right direction for occupant D. As shown in Figure 9, before the airbag 32 inflates and deploys, a portion of each of the pair of rear tethers 54 is inserted through the pair of slits 16A.

[0072] Inside each of the pair of slits 16A, there is a winding portion 60 into which the longitudinal middle portions of a pair of rear tethers 54 are wrapped from the front. These winding portions 60 are fixed to a frame (not shown) of the seat back 16.

[0073] As shown in Figure 10, when the airbag 32 inflates and deploys, the front and rear chambers 34 inflate and deploy forward. The pair of rear tethers 54, each sewn to a pair of front and rear extensions 34A, are pulled out from the pair of slits 16A and deploy forward. With this configuration, the deployment direction of the pair of rear tethers 54 can be restricted by the pair of slits 16A.

[0074] When the airbag 32 is inflated and deployed, a pair of rear tethers 54 extend in the longitudinal direction below a pair of longitudinal extensions 34A. In this state, the pair of rear tethers 54 are tilted downward toward the rear. The pretensioner mechanism 64 is configured to pull the pair of rear tethers 54 diagonally downward toward the rear after the airbag 32 has finished inflating and deploying, for example, after a predetermined time has elapsed since the activation of the inflator 44 or the detection or prediction of a collision (see arrow P1 in Figure 11).

[0075] As described above, when the pair of front and rear extensions 34A are retracted, the lower surfaces of the pair of front and rear extensions 34A are configured to contact the left and right shoulders K of the occupant D when the occupant is restrained by the airbag 32 (see Figures 12 and 13). When the occupant is restrained by the airbag 32, the airbag body 40 is supported by the tensile load of the pair of front and rear extensions 34A and the pair of rear tethers 54. In this embodiment, the occupant D is AM50, but even if the occupant D is AM95 (95th percentile of adult American males) or AF05 (5th percentile of adult American females), the maximum length of the pair of rear tethers 54 and the length to which the rear tethers 54 are retracted by the pretensioner mechanism 64 are set so that the lower surfaces of the pair of front and rear extensions 34A contact the left and right shoulders K of the occupant D.

[0076] The pair of front upper tethers 56 connect the left and right sides of the upper front portion of the airbag body 40 that inflates and deploys upward from the front and rear chambers 34 to the front portion of the pair of front and rear extensions 34A. One end of each pair of front upper tethers 56 is sewn to the left and right sides of the upper front portion of the airbag body 40 that inflates and deploys upward from the front and rear chambers 34. The other end of each pair of front upper tethers 56 is sewn to the front portion of the pair of front and rear extensions 34A. The pair of front upper tethers 56 prevent the airbag body 40 from rotating excessively upward around the connecting portion 34B when the airbag 32 has finished inflating and deploying.

[0077] The pair of front lower tethers 58 connect the left and right sides of the lower part of the airbag body 40 that inflates and deploys below the front and rear chambers 34 to the front of the pair of front and rear extensions 34A, respectively. One end of each of the pair of front lower tethers 58 is sewn to the left and right sides of the lower part of the airbag body 40 that inflates and deploys below the front and rear chambers 34, respectively. The other end of each of the pair of front lower tethers 58 is sewn to the front of the pair of front and rear extensions 34A, respectively. The pair of front lower tethers 58 prevent the airbag body 40 from rotating excessively downward around the connecting portion 34B when the airbag 32 has finished inflating and deploying.

[0078] The airbag system 30 described above includes an electronic control unit (ECU), not shown, which controls the operation of a pair of inflators 44. The control unit is electrically connected to the pair of inflators 44 and a collision sensor, not shown. Based on information from the collision sensor, the control unit is capable of detecting or predicting the occurrence (or inevitability) of various types of frontal collisions for the vehicle to which it is applied, for each type of collision described later.

[0079] The control unit is configured to activate a pair of inflators 44 when it detects or predicts a frontal collision based on information from the collision sensors. The types of frontal collisions that trigger the control unit to activate the inflators 44 include not only full-wrap frontal collisions but also offset frontal collisions such as oblique collisions and minute-wrap collisions.

[0080] Furthermore, the control device is configured to activate the pretensioner mechanism 64 after the airbag 32 has finished inflating and deploying. For example, the control device activates the pretensioner mechanism 64 after a predetermined time has elapsed since the inflator 44 was activated. Alternatively, the control device may activate the pretensioner mechanism 64 after a predetermined time has elapsed since, for example, the detection or prediction of a collision.

[0081] (action) Next, the operation of the first embodiment will be described.

[0082] The occupant protection device 10 according to this embodiment includes a vehicle seat 12 in which an occupant D sits, and an airbag device 30 that protects occupant D in the event of a vehicle collision. With this airbag device 30, gas generated from a pair of inflators 44 is supplied to the airbag 32 in the event of a vehicle collision, and the airbag 32 inflates and deploys from the rear side of the upper part of the vehicle seat 12 towards the front side of the seat.

[0083] At this time, the pair of front-to-rear extensions 34A in the front-to-rear chambers 34 of the airbag 32 inflate and deploy towards the front of the seat, passing on both sides of the head H of the occupant D seated in the vehicle seat 12. In addition, the connecting portion 34B that connects the front ends of the pair of front-to-rear extensions 34A in the left-to-right direction of the seat in the front-to-rear chambers 34 inflates and deploys with a delay compared to the pair of front-to-rear extensions 34A. Furthermore, the airbag body 40 inflates and deploys toward the occupant D at the rear side of the seat of the connecting portion 34B, with a delay compared to the front-to-rear chambers 34. When the occupant D is restrained, the airbag body 40 is compressed so as to be sandwiched between the thighs F and chest C of the occupant D, while extending the front-to-rear extensions 34A in the front-to-rear direction of the seat. This compressive deformation of the airbag body 40 absorbs the kinetic energy when the occupant moves inertially. The pair of front-to-rear extensions 34A also serve as gas passages and support the load applied to the airbag body 40 from the occupant D.

[0084] Here, the airbag 32 is connected to the seatback 16 of the vehicle seat 12 by a pair of left and right rear tethers 54. More specifically, one end of each of the left and right rear tethers 54 is secured to a pair of left and right front and rear extensions 34A, and the other end of each is secured to a pretensioner mechanism 64 provided on the seatback 16. The left and right rear tethers 54, together with the front and rear chambers, receive and support the load applied to the airbag body 40 by the occupant D.

[0085] In particular, according to the airbag device 30 of this embodiment, after the airbag 32 has finished inflating and deploying, for example, after a predetermined time has elapsed since the operation of the inflator 44 or the detection or prediction of a collision, a pair of left and right pretensioner mechanisms 64 provided on the seat back 16 are activated, and a pair of left and right rear tethers 54 are retracted. As a result, when the occupant is restrained by the airbag 32, a pair of left and right front and rear extending portions 34A are relatively retracted diagonally downward and rearward by a pair of left and right rear tethers 54, causing the connecting portion 34B to approach the thigh portion F of the occupant D. At this time, the airbag body 40 that has been inflated and deployed on the rear side of the connecting portion 34B rotates so as to tilt forward towards the seat. Therefore, the airbag body 40 fits deeply between the thigh portion F and the chest portion C of the occupant D, increasing the contact area between the occupant D and the airbag body 40. This suppresses the lifting of the airbag body 40.

[0086] Here, if the rear tether 54 is too short throughout, the airbag 32 may be pulled downwards during inflation and deployment, interfering with the occupant D's head H, and potentially preventing the airbag 32 from passing between the head H and the vehicle's roof (not shown). On the other hand, if the rear tether 54 is too long throughout, the airbag 32 may pass over the occupant D's head more easily during inflation and deployment, but the airbag body 40 may lift up during occupant restraint, potentially reducing the contact area between the occupant D and the airbag 32, and potentially causing the airbag 32 to escape above the occupant D's head.

[0087] In contrast, according to the airbag device 30 of this embodiment, the rear tether 54 is retracted by the pretensioner mechanism 64 after the airbag 32 has finished inflating and deploying. Therefore, the length of the pair of left and right rear tethers 54 in the vehicle longitudinal direction when the airbag 32 is restraining the occupant is shorter than the length of the pair of left and right rear tethers 54 when the airbag 32 is inflating and deploying. For this reason, by setting the maximum length of the rear tether 54 long enough for the airbag 32 to easily pass over the head of the occupant D when it inflates and deploys, and then retracting the rear tether 54 by the pretensioner mechanism 64 after the airbag 32 has finished inflating and deploying, it is possible to achieve both ease of deployment of the airbag 32 and stability of restraint of the occupant D.

[0088] Furthermore, according to the airbag device 30 of this embodiment, since the pair of left and right rear tethers 54 are retracted by a pair of symmetrically provided pretensioner mechanisms 64, the swinging of the airbag 32 in the vertical and horizontal directions of the seat when inflation and deployment are complete can be suppressed in a balanced and effective manner.

[0089] Furthermore, according to the airbag device 30 of this embodiment, when inflation and deployment are complete, the airbag body 40 faces the occupant D's head H, chest C, and abdomen B from the front with a gap between them. Therefore, the airbag body 40 inflates and deploys without interfering with the occupant D's head H, chest C, and abdomen B. Also, when the occupant D is restrained, the airbag body 40 can make contact with the occupant D's upper body, including the occupant D's head H, chest C, and abdomen B, over a wide area, thus effectively reducing the load applied to the occupant D from the airbag body 40.

[0090] Furthermore, according to the airbag device 30 of this embodiment, when an occupant is restrained, the pair of front-to-rear extensions 34A on the left and right sides are pulled diagonally downward and rearward by the pair of rear tethers 54 on the left and right sides, so that the lower surfaces of the pair of front-to-rear extensions 34A on the left and right sides come into contact with the left and right shoulders K of the occupant D. As a result, the vertical position of the airbag body 40 relative to the head H of the occupant D can be stabilized regardless of the difference in the occupant D's physique.

[0091] Furthermore, according to the airbag device 30 of this embodiment, the pair of left and right rear tethers 54 are connected to the front of the pair of left and right front-to-rear extensions 34A at a position that overlaps with the airbag body 40 when inflation and deployment is complete in a side view of the seat, so that the connecting portion 34B can be brought even closer to the thigh F of the occupant D.

[0092] Furthermore, according to the airbag device 30 of this embodiment, the left and right front and rear chambers 34 are formed into a bag shape by sewing the periphery portions of two overlapping base fabrics at the sewing section S1, and the left and right rear tethers 54 are sewn to the left and right front and rear extensions 34A at a part of the sewing section S1. Therefore, compared to the case where the left and right rear tethers 54 are sewn to the left and right front and rear extensions 34A at a position other than the sewing section S1, the left and right rear tethers 54 can be secured to the left and right front and rear extensions 34A with a simpler configuration. In addition, the reinforcing fabric 62 can improve the strength of the portion where the left and right rear tethers 54 are sewn to the left and right front and rear extensions 34A.

[0093] [Supplementary explanation of the first embodiment] In the first embodiment described above, the pretensioner mechanism 64 was described as being provided inside both the left and right sides of the seat back 16. However, the pretensioner mechanism is not limited to this and may be provided outside the seat back. For example, the pretensioner mechanism may be fixed to both the left and right sides of the seat back. In this case, the seat back does not need to have slits.

[0094] (First variation) Furthermore, as shown in the first modified airbag device 65 in Figure 14, the pretensioner mechanism 64 may be provided inside the module case 46. In the following modified examples and embodiments, components identical to those in the first embodiment are denoted by the same reference numerals and their descriptions are omitted as appropriate.

[0095] In the first modified example, when the front and rear chambers 34 inflate and deploy forward during the inflation and deployment of the airbag 32, the pair of rear tethers 54 are pulled out from the module case 46 and deployed forward through the pair of slits 16A. Thus, similar to the first embodiment, the deployment direction of the pair of rear tethers 54 can be restricted by the pair of slits 16A.

[0096] (Second variation) Furthermore, as shown in the second modified airbag device 67 in Figure 15, the pretensioner mechanism 64 may be fixed to the vehicle body (not shown). For example, the pretensioner mechanism 64 is fixed to the vehicle body on the rear side of the seat back 16 and above the inflator 44. The longitudinal middle portions of the pair of rear tethers 54 are wrapped around the winding portion 60 from below. As shown in Figure 15, when the airbag 32 is inflated and deployed, the pair of rear tethers 54 are bent at the portion that is wrapped around the pair of winding portions 60. In this embodiment as well, basically the same effects as in the first embodiment can be obtained.

[0097] <Second Embodiment> Hereinafter, an occupant protection device 66 according to a second embodiment of the present invention will be described with reference to Figures 16 to 25. As shown in Figure 16, the occupant protection device 66 is composed of a vehicle seat 12 and an airbag device 70.

[0098] The airbag system 70 comprises an airbag 72, a pair of inflators 44 (see Figure 17), and a module case 46. Normally, the airbag 72 is stored in the module case 46 together with the pair of inflators 44 in a folded state.

[0099] The airbag 72 receives gas from a pair of inflators 44 and inflates and deploys (deploys and inflates) from the rear to the front of the upper part of the vehicle seat 12. The airbag 72 has front and rear chambers 74 and an airbag body 40. The front and rear chambers 74 have a pair of left and right front and rear extending portions 74A that inflate and deploy forward, passing on both sides of the occupant D's head H, and a connecting portion 74B that connects the front ends of the pair of front and rear extending portions 74A in the left and right direction. The longitudinal ends of the front and rear chambers 74 are a pair of left and right inflator housing portions 74C (see Figure 18) that house the pair of inflators 44. The airbag body 40 inflates and deploys toward the occupant D side (rear side) behind the front and rear chambers 74 at the rear side of the connecting portion 74B.

[0100] As shown in Figure 18, the front and rear chambers 74 are formed into a long bag shape by overlapping two long base fabrics 78 and 80 and sewing the periphery at the sewing section S1. The two base fabrics 78 and 80 are made of a stretchable nylon-based fabric.

[0101] Here, as shown in Figure 16, the airbag 72 is fitted with a pair of left and right rear tethers 76, a pair of left and right front upper tethers 56, and a pair of left and right front lower tethers 58. Each end of the pair of rear tethers 76 is secured to the longitudinal middle portion of a pair of front and rear extensions 74A. In detail, each end of the pair of rear tethers 76 is sewn to the pair of front and rear extensions 74A at a position that overlaps with the airbag body when inflation and deployment are complete in a side view of the seat. As shown in Figure 18, the front and rear chambers 74 are provided with extensions 75. The extensions 75 are formed in a substantially trapezoidal shape by extending to one side in the width direction from two base fabrics 78 and 80. Each end of the pair of rear tethers 76 is sewn at a sewing section S4 provided on the extension 75. In other words, one end of each of the pair of rear tethers 76 is sewn to a pair of front and rear extensions 74A in a separate sewing section S4, which is provided in the seam allowance portion of the sewing section S1. This prevents the sewing section S1 from being subjected to load when the front and rear extensions 34A are pulled by the rear tether 54.

[0102] As shown in Figure 19, the pair of rear tethers 76 are composed of two long strips of fabric 76A and 76B. The fabrics 76A and 76B are, for example, made of PET (polyethylene terephthalate), which is not easily stretched.

[0103] As shown in Figure 17, each other end of the rear tether 54 is secured to a pair of left and right fixing parts 81 located inside the left and right sides of the seat back 16.

[0104] As shown in Figure 20, the two pieces of fabric 76A and 76B that make up the pair of rear tethers 76 each include a pair of sewn sections 82 sewn linearly along the longitudinal direction at both ends in the short direction, a pair of sewn sections 84 sewn linearly parallel to the sewn sections 82 and linearly along the longitudinal direction on the short side of the rear tether 76 relative to the pair of sewn sections 82, and a plurality of sewn sections 86 provided between the pair of sewn sections 84 at intervals along the longitudinal direction of the rear tether 76. In this embodiment, these sewn sections 82, 84, and 86 correspond to the reinforcing sewn sections in the present invention. The sewn sections 82, 84, and 86 make the pair of rear tethers 76 less likely to stretch in the longitudinal direction.

[0105] Each of the multiple sewing sections 86 is composed of a rectangular sewing section 86A and an X-shaped sewing section 86B sewn diagonally to the sewing section 86A. The multiple sewing sections 86 are arranged in the longitudinal direction at intervals of approximately the same dimension as or larger than the longitudinal dimension of each sewing section 86.

[0106] As shown in Figure 21A, the pair of front and rear extensions 74A each have a weave pattern oblique to the longitudinal direction. As a result, as shown in Figure 21B, when a tensile load is applied along the longitudinal direction of the front and rear extensions 74A, the front and rear extensions 74A are stretched well.

[0107] On the other hand, as shown in Figure 22A, each of the pair of rear tethers 76 has a weave parallel to the longitudinal direction. As a result, as shown in Figure 22B, even when a tensile load is applied along the longitudinal direction of the rear tether 76, the rear tether 76 hardly stretches compared to the pair of front and rear extensions 74A. In other words, the pair of rear tethers 76 are less likely to stretch than the pair of front and rear extensions 74A due to the direction of the weave.

[0108] (action) Next, the operation of the second embodiment will be described.

[0109] The occupant protection device 66 according to this embodiment includes a vehicle seat 12 in which occupant D sits, and an airbag device 70 that protects occupant D in the event of a vehicle collision. With this airbag device 70, gas generated from a pair of inflators 44 is supplied to the airbag 72 in the event of a vehicle collision, and the airbag 72 inflates and deploys from the rear side of the upper part of the vehicle seat 12 towards the front side of the seat.

[0110] As shown in Figure 23, the pair of front-to-rear extensions 74A in the front-to-rear chambers 74 of the airbag 72 inflate and deploy towards the front of the seat, passing on both sides of the head H of the occupant D seated in the vehicle seat 12. In addition, the connecting portion 74B that connects the front ends of the pair of front-to-rear extensions 74A in the left-to-right direction of the seat in the front-to-rear chambers 74 inflates and deploys with a delay compared to the pair of front-to-rear extensions 74A. Furthermore, the airbag body 40 inflates and deploys toward the occupant D at the rear side of the connecting portion 74B, with a delay compared to the front-to-rear chambers 74. As shown in Figures 24 and 25, when the occupant D is restrained, the airbag body 40 is compressed so as to be sandwiched between the thighs F and chest C of the occupant D, while extending the front-to-rear extensions 74A in the front-to-rear direction of the seat. This compressive deformation of the airbag body 40 absorbs the kinetic energy of the occupant D as it moves inertially. Furthermore, the pair of front-to-rear extensions 74A on the left and right sides serve as gas passages and also support the load applied to the airbag body 40 by the occupant D.

[0111] Here, the airbag 72 is connected to the seatback 16 of the vehicle seat 12 by a pair of left and right rear tethers 76. More specifically, one end of each of the left and right rear tethers 76 is secured to a pair of left and right front and rear extensions 74A, and the other end of each is secured to the seatback 16. The left and right rear tethers 54, together with the front and rear chambers, receive and support the load applied to the airbag body 40 by the occupant D.

[0112] In particular, according to the airbag device 70 of this embodiment, the pair of rear tethers 76 are less prone to stretching compared to the case where they are made of a single piece of fabric, because they are made of two pieces of fabric 76A and 76B that are overlapped and sewn together. Furthermore, the pair of rear tethers 76 are made of a material that is less prone to stretching than the pair of front and rear extending portions 74A, making them even more prone to stretching. Moreover, each of the pair of rear tethers 76 is sewn by sewing portions 82, 84, and 86 that are provided along the longitudinal direction, making them even more prone to stretching in the longitudinal direction. Furthermore, while the pair of front and rear extending portions 74A have a weave that is diagonal to the longitudinal direction, the pair of rear tethers 76 have a weave that is parallel to the longitudinal direction. Therefore, the pair of rear tethers 76 are even more prone to stretching in the longitudinal direction.

[0113] As described above, the pair of rear tethers 76 are difficult to stretch in the longitudinal direction. Therefore, when the occupant is restrained by the airbag 72, the pair of front-to-rear extending portions 74A are relatively pulled in diagonally downward and rearward by the pair of rear tethers 76, and the connecting portion 74B approaches the occupant's thigh. At this time, the airbag body 40, which has inflated and deployed on the rear side of the connecting portion 74B, rotates so as to tilt forward towards the seat. As a result, the airbag body 40 fits deeply between the occupant D's thigh F and chest C, increasing the contact area between the occupant D and the airbag 32. This suppresses the lifting of the airbag body 40.

[0114] Furthermore, the sewing sections 82 and 84 are provided continuously in the longitudinal direction of the pair of rear tethers 76. This effectively suppresses the longitudinal extension of the pair of rear tethers 76.

[0115] Furthermore, multiple stitched sections 86 are provided at intervals along the longitudinal direction of the pair of rear tethers 76. In other words, the pair of rear tethers have alternating sections along their longitudinal direction where stitched sections 86 are provided and sections where stitched sections 86 are not provided. This makes it easy to fold the pair of rear tethers 76, allowing the airbag to be compactly housed.

[0116] [Supplementary explanation of the second embodiment] In the second embodiment described above, the other ends of the pair of rear tethers 76 were described as being secured to a pair of left and right fixing parts 81 provided inside the left and right sides of the seat back 16, respectively, but the invention is not limited to this. For example, the other ends of the pair of rear tethers 76 may be secured to a pair of left and right fixing parts provided on the left and right sides of the seat back 16. Alternatively, the other ends of the pair of rear tethers 76 may be secured to fixing parts provided on the vehicle body (not shown).

[0117] Furthermore, in the second embodiment described above, the fabric materials 76A and 76B of the pair of rear tethers 76 were described as being sewn together by a pair of sewing sections 82, a pair of sewing sections 84, and a plurality of sewing sections 86, but the invention is not limited to this. The rear tethers can be sewn together by reinforcing sewing sections of various shapes, at least a portion of which are aligned along the longitudinal direction.

[0118] (First variation) For example, as shown in the first modified example in Figure 26, the fabric material 76A and fabric material 76B of the pair of rear tethers 76 may be sewn together only by a pair of sewing sections 82 and a pair of sewing sections 84.

[0119] (Second variation) Furthermore, as shown in the second modified example in Figure 27, the fabric materials 76A and 76B of the pair of rear tethers 76 may be sewn together by a pair of sewing sections 82 and a pair of sewing sections 88 arranged at equal intervals between the pair of sewing sections 82. The pair of sewing sections 88 are sewn in a straight line continuously in the longitudinal direction at the center of the rear tether 76 in the short direction. According to this modified example, since the pair of sewing sections 82 and the pair of sewing sections 88 (a total of four straight sewing sections) are sewn at equal intervals in the short direction, the longitudinal extension of the rear tether 76 is suppressed even more effectively.

[0120] (Third variation) Furthermore, as shown in the third modified example in Figure 28, the fabric materials 76A and 76B of the pair of rear tethers 76 may be sewn together by a pair of sewing sections 82 and a pair of sewing sections 90 that are arranged at equal intervals between the pair of sewing sections 82 and spaced apart in the longitudinal direction of the rear tether 76.

[0121] (Fourth variation) Furthermore, as shown in the fourth modified example in Figures 29 and 30, each pair of rear tethers 92 may be made from a single piece of fabric. In the fourth modified example, each pair of rear tethers 92 is provided with a plurality of sewn sections 86 spaced apart in the longitudinal direction. In other words, each pair of rear tethers 76 has seamless sections 94 between the plurality of sewn sections 86. The seamless sections 94 can be easily folded. This makes it even easier to fold the pair of rear tethers 92.

[0122] (Fifth variation) Furthermore, as shown in the fifth modified example in Figure 31, a pair of rear tethers 92, each composed of a single piece of fabric, may have only one sewn section 96 sewn linearly along the longitudinal direction at the center in the short direction. In this modified example, the longitudinal extension of the rear tethers 92 can be suppressed with the simplest configuration.

[0123] [Supplementary explanation of the above embodiment] In the first embodiment and its various modifications, the pair of rear tethers 54 were described as being composed of a single piece of fabric. In the second embodiment and its first to third modifications, the pair of rear tethers 76 were described as being composed of two pieces of fabric 76A and 76B. Furthermore, in the fourth and fifth modifications of the second embodiment, the pair of rear tethers 92 were described as being composed of a single piece of fabric. However, the number of fabric pieces constituting the rear tether can be any number. Note that the more fabric pieces there are, the less the rear tether will stretch.

[0124] Furthermore, in the first embodiment described above, an occupant protection device 10 was described in which a pair of front and rear extensions 34A are relatively pulled in diagonally downward and rearward of the seat by a pair of pretensioner mechanisms 64 that pull in a pair of rear tethers 54. Furthermore, in the second embodiment described above, an occupant protection device 66 was described in which a pair of front and rear extensions 74A are relatively pulled in diagonally downward and rearward of the seat by a rear tether 76 configured to be difficult to stretch. The occupant protection device is not limited to these, and may include both a pretensioner mechanism and a rear tether that is difficult to stretch. For example, the rear tether 54 of the first embodiment may be replaced with the rear tether 76 of the second embodiment.

[0125] The following additional information is disclosed regarding the embodiments described above.

[0126] (Note 1) An inflator that generates gas in the event of a vehicle collision, The aforementioned gas is supplied to an airbag that inflates and deploys from the rear side of the vehicle seat towards the front side of the seat, A pair of left and right rear tethers connecting the airbag to the seatback of the vehicle seat or the vehicle body, It has, The aforementioned airbag, A front and rear chamber comprising: a pair of left and right front and rear extending portions that expand and unfold toward the front of the seat, passing through both sides of the head of an occupant seated in the vehicle seat; and a connecting portion that connects the front ends of the pair of left and right front and rear extending portions in the left-right direction of the seat when the expansion and unfolding is complete; The airbag body, located at the rear of the seat at the connecting portion, expands and deploys toward the occupant after the front and rear chambers, and when the occupant is restrained, the front and rear extending portion extends in the front-rear direction of the seat, while being compressed so as to be sandwiched between the occupant's thighs and chest, Equipped with, The pair of rear tethers are configured such that one end of each is secured to the pair of front-to-rear extensions, and the other end of each is secured to the seat back or the vehicle body, and when the occupant is restrained, the pair of front-to-rear extensions are pulled relatively downward and diagonally towards the rear of the seat, bringing the connecting portion closer to the occupant's thighs. Vehicle airbag system. (Note 2) The seatback or the vehicle body is provided with a pair of left and right pretensioner mechanisms that retract the left and right pair of rear tethers after the airbag has finished inflating and deploying. Vehicle airbag system as described in Appendix 1. (Note 3) The pair of left and right pretensioner mechanisms are provided symmetrically on both the left and right sides of the seat back. Vehicle airbag system as described in Appendix 2. (Note 4) The longitudinal elongation rate of the pair of left and right rear tethers is smaller than the longitudinal elongation rate of the pair of left and right front and rear extending portions. A vehicle airbag system as described in any one of the appendices 1 to 3. (Note 5) The pair of left and right rear tethers are made of a material that is less prone to stretching than the pair of left and right front-to-back extending portions. Vehicle airbag system as described in Appendix 4. (Note 6) The pair of left and right rear tethers have a weave parallel to the longitudinal direction, and the pair of left and right front and rear extending portions have a weave oblique to the longitudinal direction. Vehicle airbag devices as described in Appendix 4 or Appendix 5. (Note 7) The pair of rear tethers described above are each provided with a reinforcing seam that is sewn along the longitudinal direction, A vehicle airbag system as described in any one of the appendices 4 to 6. (Note 8) The reinforcing stitching is provided continuously in the longitudinal direction of the pair of left and right rear tethers. Vehicle airbag system as described in Appendix 7. (Note 9) The reinforcing stitching portions are provided in multiple locations, spaced apart in the longitudinal direction of the pair of left and right rear tethers. Vehicle airbag system as described in Appendix 7. (Note 10) When the airbag body has completed inflation and deployment, it faces the occupant's head, chest, and abdomen from the front, with a gap between them. A vehicle airbag system as described in any one of the notes 1 to 9. (Note 11) The lower surfaces of the pair of front-to-back extending portions on the left and right sides are configured to contact the left and right shoulders of the occupant when the occupant is restrained. A vehicle airbag system as described in any one of the appendices 1 to 10. (Note 12) Each of the pair of left and right rear tethers is connected to the front of the pair of left and right front extensions at a position that overlaps with the airbag body when inflation and deployment are complete, as viewed from the side of the seat. A vehicle airbag system as described in any one of the appendices 1 to 11. (Note 13) The pair of front and rear chambers are formed into a bag shape by sewing the periphery of two overlapping base fabrics together at the periphery seam. The pair of left and right rear tethers are sewn to the pair of left and right front and rear extensions in a portion of the peripheral stitching portion. A vehicle airbag system as described in any one of the appendices 1 to 12. (Note 14) The pair of left and right rear tethers are sewn together with the reinforcing fabric to the two base fabrics of the pair of left and right front and rear extending portions at the peripheral seam. Vehicle airbag system as described in Appendix 13. (Note 15) A vehicle seat in which the occupants sit, A vehicle airbag device described in any one of the appendices 1 to 14, mounted on the rear side of the upper part of the vehicle seat, Crew protection device equipped with a occupant protection device. [Explanation of Symbols]

[0127] 10.66 Crew protection devices 12 Vehicle seats 16 Seatback 30, 65, 70 Airbag System 32, 72 airbags 34, 74 front and rear chambers 34A, 74A Front and rear extensions 34B, 74B connection part 36, 38, 78, 80 base fabric 40 Airbag Unit 44 Inflators 54, 76, 92 Rear tether 62 Reinforcement fabric 64 Pretensioner mechanism 82, 84, 88, 90, 96 Sewing section (reinforced sewing section) B Abdomen B Abdomen C Chest D Crew F thigh K Shoulder H head S1 Sewing section (peripheral sewing section)

Claims

1. An inflator that generates gas in the event of a vehicle collision, The aforementioned gas is supplied to an airbag that inflates and deploys from the rear side of the vehicle seat towards the front side of the seat, A pair of left and right rear tethers connecting the airbag to the seatback of the vehicle seat or the vehicle body, It has, The aforementioned airbag, A front and rear chamber comprising: a pair of left and right front and rear extending portions that expand and unfold toward the front of the seat, passing through both sides of the head of an occupant seated in the vehicle seat; and a connecting portion that connects the front ends of the pair of left and right front and rear extending portions in the left-right direction of the seat when the expansion and unfolding is complete; The airbag body, located at the rear of the seat at the connecting portion, expands and deploys toward the occupant after the front and rear chambers, and when the occupant is restrained, the front and rear extending portion extends in the front-rear direction of the seat, while being compressed so as to be sandwiched between the occupant's thighs and chest, Equipped with, The pair of rear tethers are configured such that one end of each is secured to the pair of front-to-rear extensions, and the other end of each is secured to the seat back or the vehicle body, and when the occupant is restrained, the pair of front-to-rear extensions are pulled relatively downward and diagonally towards the rear of the seat, bringing the connecting portion closer to the occupant's thighs. Vehicle airbag system.

2. The seatback or the vehicle body is provided with a pair of left and right pretensioner mechanisms that retract the left and right pair of rear tethers after the airbag has finished inflating and deploying. The vehicle airbag device according to claim 1.

3. The pair of left and right pretensioner mechanisms are provided symmetrically on both the left and right sides of the seat back. The vehicle airbag device according to claim 2.

4. The longitudinal elongation rate of the pair of left and right rear tethers is smaller than the longitudinal elongation rate of the pair of left and right front and rear extending portions. The vehicle airbag device according to claim 1.

5. The pair of left and right rear tethers are made of a material that is less prone to stretching than the pair of left and right front-to-back extending portions. The vehicle airbag device according to claim 4.

6. The pair of left and right rear tethers have a weave parallel to the longitudinal direction, and the pair of left and right front and rear extending portions have a weave oblique to the longitudinal direction. The vehicle airbag device according to claim 4.

7. The pair of rear tethers described above are each provided with a reinforcing seam that is sewn along the longitudinal direction, The vehicle airbag device according to claim 4.

8. The reinforcing stitching is provided continuously in the longitudinal direction of the pair of left and right rear tethers. The vehicle airbag device according to claim 7.

9. The reinforcing stitching portions are provided in multiple locations, spaced apart in the longitudinal direction of the pair of left and right rear tethers. The vehicle airbag device according to claim 7.

10. When the airbag body has completed inflation and deployment, it faces the occupant's head, chest, and abdomen from the front, with a gap between them. The vehicle airbag device according to claim 1.

11. The lower surfaces of the pair of front-to-back extending portions on the left and right sides are configured to contact the left and right shoulders of the occupant when the occupant is restrained. The vehicle airbag device according to claim 10.

12. Each of the pair of left and right rear tethers is connected to the front of the pair of left and right front extensions at a position that overlaps with the airbag body when inflation and deployment are complete, as viewed from the side of the seat. The vehicle airbag device according to claim 1.

13. The pair of front and rear chambers are formed into a bag shape by sewing the periphery of two overlapping base fabrics together at the periphery seam. The pair of left and right rear tethers are sewn to the pair of left and right front and rear extensions in a portion of the peripheral stitching portion. The vehicle airbag device according to claim 1.

14. The pair of left and right rear tethers are sewn together with the reinforcing fabric to the two base fabrics of the pair of left and right front and rear extending portions at the peripheral seam. The vehicle airbag device according to claim 13.

15. A vehicle seat in which the occupants sit, A vehicle airbag device according to any one of claims 1 to 14, mounted on the rear side of the upper part of the vehicle seat, Crew protection device equipped with a occupant protection device.

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