Vehicle airbag device and occupant protection apparatus

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 an airbag device for a vehicle and an occupant protection device. [Background technology]

[0002] The following Patent Document 1 discloses an airbag device including an inflator that generates high-pressure gas when an impact is applied, and a bag (airbag) that receives the gas from the inflator and inflates and deploys from a seat back of a vehicle seat. The bag includes a torso support part that deploys from behind the head of a seated occupant to the front of the occupant, and a pair of head support parts that deploy on both the left and right sides of the occupant's head and are connected to the torso support part. In the technology described in the following Patent Document 1, the deployed torso support part is connected to the seat or the vehicle body by a belt-shaped connecting member. As a result, the movement of the deployed torso support part is restricted by the connecting member.

[0003] Also, the following Patent Document 2 discloses an airbag device including an inflator and an airbag that is inflated by gas supplied from the inflator. The airbag has a rear inflatable portion that is inflated on the back side of the seat, a pair of side inflatable portions that extend forward from both the left and right sides of the rear inflatable portion, and a pair of front inflatable portions that extend from the side inflatable portions to the center and are connected to each other at the center to cover the front of the occupant. Furthermore, the airbag device described in the following Patent Document 2 includes a belt-shaped connecting member that connects a pair of support points provided on the front side of the seat and both the left and right sides of the seat to the side inflatable portions. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-018593 A [Patent Document 2] JP 2019-218014 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the technologies described in Patent Document 1 and Patent Document 2, the airbag is deployed from behind the occupant's head to in front of the head, so if the connecting member is short, the airbag may be pulled downwards on the seat when the airbag is deployed and may not be able to pass between the occupant's head and the roof of the vehicle. Also, if the connecting member is long, the airbag may easily pass over the occupant's head when the airbag is deployed, but the airbag body may rise when the occupant is restrained, reducing the contact area between the occupant and the airbag, and the airbag may slip out above the occupant's head. In other words, there is room for improvement in achieving both ease of deployment of the airbag and stability in restraining the occupant.

[0006] SUMMARY OF THE PRESENT INVETION The present invention has been made in consideration of the above circumstances, and has an object to provide a vehicle airbag device that can achieve both ease of deployment of an airbag and stability in restraining an occupant, and an occupant protection device including the same. [Means for solving the problem]

[0007] The vehicle airbag device of the first aspect includes an inflator that generates gas when a vehicle crashes, an airbag that is supplied with the gas and inflates and deploys from the rear side of an upper portion of a vehicle seat to the front side of the seat, and a pair of left and right rear tethers that connect the airbag to a seat back of the vehicle seat or a vehicle body, and the airbag is a front-rear tether that includes a pair of left and right front-rear extending portions that inflate and deploy toward the front side of the seat by passing through the left and right sides of the head of an occupant seated in the vehicle seat, and a connecting portion that connects front ends of the pair of left and right front-rear extending portions in the left-right direction of the seat when inflation and deployment are completed. and an airbag body that inflates and deploys toward the occupant on the seat rear side of the connecting portion after the front and rear chambers, and that, when the occupant is restrained, extends the front and rear extensions in the front-to-rear direction of the seat and is compressed so as to be sandwiched between the thighs and chest of the occupant.The pair of left and right rear tethers have one end secured to the pair of left and right front and rear extensions and the other end secured to the seat back or the vehicle body, and are configured to relatively retract the pair of left and right front and rear extensions diagonally downward toward the rear of the seat when the occupant is restrained, thereby bringing the connecting portion closer to the thighs of the occupant.

[0008] According to the vehicle airbag device of the first aspect, gas generated from the inflator is supplied to the airbag when the vehicle crashes, and the airbag inflates and deploys from the rear side of the upper part of the vehicle seat to the front side of the seat. At this time, the pair of left and right front and rear extensions in the front and rear chambers inflate and deploy toward the front side of the seat through the left and right sides of the head of the occupant seated in the vehicle seat. The airbag body inflates and deploys toward the occupant on the rear side of the seat of the connecting part, delayed from the front and rear chambers. When the occupant is restrained, the airbag body is compressed so as to be sandwiched between the thighs and chest of the occupant while the front and rear extensions are stretched in the front and rear directions of the seat. This compressive deformation of the airbag body absorbs kinetic energy when the occupant moves due to inertia. The pair of left and right front and rear extensions serve as gas flow paths and support the load applied to the airbag body by the occupant. However, the term "pulling the airbag body diagonally downward and rearward" as used herein is intended to broadly include the concept of applying a load diagonally downward and rearward to the pair of left and right front and rear extending portions of the seat so that the airbag body does not lift up.

[0009] Here, the airbag is connected to the seat back of the vehicle seat or the vehicle body by a pair of left and right rear tethers. More specifically, one end of each of the pair of left and right rear tethers is anchored to a pair of left and right front and rear extensions, and the other end of each of the pair of left and right rear tethers is anchored to the seat back or the vehicle body. The pair of left and right rear tethers receive the load applied to the airbag body from the occupant together with the front and rear chambers, and serve as support. When the airbag restrains the occupant, the pair of left and right front and rear extensions are relatively drawn in diagonally downward toward the rear of the seat by the pair of left and right rear tethers, and the connecting portion approaches the thighs of the occupant. At this time, the airbag body that is inflated and deployed on the seat rear side of the connecting portion rotates so as to fall toward the front side of the seat. Therefore, the airbag body penetrates deeply between the thighs and chest of the occupant, and the contact area between the occupant and the airbag increases. This suppresses the airbag body from being lifted up.

[0010] In the vehicle airbag device of the second aspect, in the first aspect, a pair of left and right pretensioner mechanisms are provided on the seat back or the vehicle body, which retract the pair of left and right rear tethers after the airbag has been fully inflated and deployed.

[0011] According to the vehicle airbag device of the second aspect, after the airbag is fully inflated and deployed, a pair of left and right pretensioner mechanisms provided on the seat back or the vehicle body are activated, and the pair of left and right rear tethers are retracted. The pair of left and right front and rear extensions are strongly retracted diagonally downward toward the 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 airbag restrains the occupant 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 the maximum length of the rear tethers when the airbag is inflated and deployed longer. This makes it easier for the airbag to pass through a narrow gap above the occupant's head, while reliably preventing the airbag body from being lifted when the occupant is restrained.

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

[0013] According to the vehicle airbag device of the third aspect, a pair of left and right rear tethers are retracted by a pair of pretensioner mechanisms arranged symmetrically on the left and right, thereby effectively suppressing the swaying of the airbag in the up-down direction and the front-to-rear direction of the seat when inflation and deployment is complete in a balanced manner.

[0014] The vehicle airbag device of a fourth aspect is the first aspect, wherein the longitudinal extensibility of the pair of left and right rear tethers is smaller than the longitudinal extensibility of the pair of left and right front and rear extending portions.

[0015] According to the vehicle airbag device of the fourth aspect, when the airbag is inflated and deployed, the pair of left and right front and rear extensions mainly receive a tensile load and extend. When the airbag restrains an occupant, the tensile load is distributed by the pair of left and right front and rear extensions and the pair of left and right rear tethers that are difficult to stretch, and the airbag body is supported. The pair of left and right front and rear extensions that are easy to stretch further in the longitudinal direction as the occupant's upper body falls toward the front side of the seat. Here, the pair of left and right rear tethers that are difficult to stretch apply a load to the pair of left and right front and rear extensions obliquely downward toward the rear of the seat. As a result, the airbag body rotates so as to fall toward the front side of the seat and is deformed into a wedge shape in a side view of the seat. As a result, the contact area between the occupant's thighs and the connecting portion of the airbag is further increased, and the lifting of the airbag body is suppressed. Therefore, with a simple configuration, the airbag can easily pass through a narrow gap above the occupant's head while suppressing the lifting of the airbag body.

[0016] A fifth aspect of the vehicle airbag device is based on the fourth aspect, wherein 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 and rear extending portions.

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

[0018] The vehicle airbag device of a sixth aspect is the fourth aspect, wherein the pair of left and right rear tethers have a grain that is parallel to the longitudinal direction, and the pair of left and right front and rear extending portions have a grain that is oblique to the longitudinal direction.

[0019] According to the vehicle airbag device of the sixth aspect, the longitudinal stretch rate of the pair of left and right rear tethers can be made smaller than the longitudinal stretch rate of the pair of left and right front and rear extending parts by using a difference in the direction of the fabric. Therefore, with a simpler configuration, the airbag can easily pass through a narrow gap above the head of an occupant while preventing the airbag body from lifting up.

[0020] A seventh aspect of the vehicle airbag device is the fourth aspect, wherein the pair of left and right rear tethers are provided with reinforcing sewn portions at least partially sewn along the longitudinal direction.

[0021] According to the seventh aspect of the vehicle airbag device, at least a part of the reinforcing sewn portion is sewn along the longitudinal direction of the pair of left and right rear tethers, so that the pair of left and right rear tethers are prevented from stretching in the longitudinal direction. Therefore, with a simpler configuration, the airbag can easily pass through a narrow gap above the head of an occupant while preventing the airbag body from lifting up.

[0022] The vehicle airbag device of an eighth aspect is the seventh aspect, wherein the reinforcing sewn portions are provided continuously in the longitudinal direction of the pair of left and right rear tethers.

[0023] According to the vehicle airbag device of the eighth aspect, the reinforcing sewn portions are provided continuously in the longitudinal direction of the pair of left and right rear tethers, so that stretching of the pair of left and right rear tethers in the longitudinal direction is more effectively suppressed.

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

[0025] According to the ninth aspect of the vehicle airbag device, the pair of left and right rear tethers have portions with reinforcing sewn parts and portions without reinforcing sewn parts arranged alternately along the longitudinal direction, which makes it easy to fold the pair of left and right rear tethers and allows the airbag to be stored compactly.

[0026] In the vehicle airbag device of a tenth aspect, in the first aspect, the airbag main body upon completion of inflation and deployment faces the head, chest and abdomen of the occupant from the front side with a gap therebetween.

[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. Meanwhile, when the occupant is restrained, the airbag body can bring the occupant's upper body, including the head, chest, and abdomen, into contact with the airbag body over a wide area, thereby effectively reducing the load applied from the airbag body to the occupant.

[0028] The vehicle airbag device of an eleventh aspect is the tenth aspect, wherein the lower surfaces of the pair of left and right front and rear extending portions come into contact with left and right shoulders of the occupant when the occupant is restrained.

[0029] According to the vehicle airbag device of the eleventh aspect, when an occupant is restrained by the airbag, the pair of left and right front and rear extending portions are pulled diagonally downward toward the rear of the seat by the pair of left and right rear tethers, so that the lower surfaces of the pair of left and right front and rear extending portions abut against the left and right shoulders of the occupant, thereby stabilizing the position of the airbag body relative to the occupant's head in the vertical direction of the seat regardless of the physique of the occupant.

[0030] In the vehicle airbag device of the 12th aspect, in the first aspect, one end of each of the pair of left and right rear tethers is connected to the front of the pair of left and right front and rear extending portions at a position that overlaps with the airbag main body when the inflation and deployment is completed in a side view of the seat.

[0031] According to the vehicle airbag device of the twelfth aspect, the pair of left and right rear tethers are connected to the front portions of the pair of left and right front-rear extending portions at positions that overlap with the airbag body when inflation and deployment are complete in a side view of the seat, thereby enabling the connecting portions to be effectively brought close to the thighs of the occupant.

[0032] In the vehicle airbag device of the thirteenth aspect, in the first aspect, the pair of left and right front and rear chambers are formed into a bag shape by sewing the peripheral edges of two overlapping base fabrics at a sewing portion, and the pair of left and right rear tethers are each sewn to the pair of left and right front and rear extending portions at a portion of the sewing portion.

[0033] According to the vehicle airbag device of the thirteenth aspect, the pair of left and right rear tethers are sewn to the peripheral sewn portions of the pair of left and right front and rear extending portions, respectively. Therefore, compared to a case in which the pair of left and right rear tethers are sewn to the pair of left and right front and rear extending portions at positions different from the peripheral sewn portions, the pair of left and right rear tethers can be engaged with the pair of left and right front and rear extending portions with a simple configuration, and the strength of the airbag can be maintained.

[0034] The vehicle airbag device of a fourteenth aspect is based on the thirteenth aspect, and the pair of left and right rear tethers, together with a reinforcing cloth, are sewn to the two base cloths of the pair of left and right front and rear extending portions at the peripheral sewn portion.

[0035] According to the vehicle airbag device of the fourteenth aspect, the reinforcing fabric can improve the strength of the portions where the pair of left and right rear tethers are sewn to the pair of left and right front and rear extending portions.

[0036] The occupant protection device of a fifteenth aspect includes a vehicle seat on which an occupant sits, and a vehicle airbag device according to any one of the first to fourteenth aspects mounted on the upper rear side of the vehicle seat.

[0037] According to the occupant protection device of the fifteenth aspect, 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 upper part of the vehicle seat to the front side of the seat. At this time, the pair of left and right front and rear extensions in the front and rear chambers inflate and deploy toward the front side of the seat through the left and right sides of the head of the occupant seated in the vehicle seat. The airbag body inflates and deploys toward the occupant on the rear side of the seat of the connecting part, delayed from the front and rear chambers. When the occupant is restrained, the airbag body is compressed so as to be sandwiched between the thighs and chest of the occupant while the front and rear extensions are stretched in the front and rear directions of the seat. This compression deformation of the airbag body absorbs kinetic energy when the occupant moves due to inertia. The pair of left and right front and rear extensions serve as gas flow paths and support the airbag body by receiving the load applied to the airbag body by the occupant.

[0038] Here, the pair of left and right rear tethers, together with the front and rear chambers, receive the load applied to the airbag body by the occupant and act as support. When the airbag restrains the occupant, the pair of left and right front and rear extensions are pulled diagonally downward toward the rear of the seat by the pair of left and right rear tethers, and the connecting parts move closer to the thighs of the occupant. This increases the contact area between the occupant and the airbag, and prevents the airbag from lifting up. Effect of the Invention

[0039] As described above, the vehicle airbag device of the first aspect has the excellent effect of achieving both ease of deployment of the airbag and stability in restraining the occupant.

[0040] The vehicle airbag device of the second aspect has the excellent effect of making it easier for the airbag to pass through narrow gaps above the head of an occupant, while reliably preventing the airbag body from being lifted when an occupant is restrained.

[0041] The vehicle airbag device of the third aspect has an excellent effect of effectively suppressing rocking movement of the airbag in the seat up-down direction and the seat front-rear direction in a balanced manner when inflation and deployment are completed.

[0042] The vehicle airbag devices according to the fourth to seventh aspects have an excellent effect of being able to achieve both ease of deployment of the airbag and stability in restraining the occupant with a simple configuration.

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

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

[0045] The vehicle airbag device of the tenth aspect has the excellent effect of suppressing interference of the airbag body with the head, chest, and abdomen of the occupant when inflated and deployed, while effectively reducing the load applied from the airbag body to the occupant when the occupant is restrained.

[0046] The vehicle airbag device of the eleventh aspect has an excellent effect of being able to stabilize the position of the airbag body relative to the occupant's head in the vertical direction of the seat, regardless of differences in occupant physique.

[0047] The vehicle airbag device of the twelfth aspect has the excellent effect of being able to effectively bring the connecting portion close to the thighs of the occupant.

[0048] The vehicle airbag device of the thirteenth aspect has an excellent effect in that the pair of left and right rear tethers can be anchored to the pair of left and right front and rear extending portions with a simple configuration, and the strength of the airbag can be maintained.

[0049] The vehicle airbag device of the fourteenth aspect has the excellent effect of improving the strength of the airbag.

[0050] The occupant protection device of the fifteenth aspect has the excellent effect of achieving both ease of deployment of an airbag mounted in a vehicle seat and stability of restraint of an occupant seated in the vehicle seat. [Brief description of the drawings]

[0051] [Figure 1] 1 is a perspective view showing a state in which an airbag is inflated and deployed in an occupant protection device according to a first embodiment. [Diagram 2] 2 is a side view showing the configuration shown in FIG. 1 as viewed from the left side of the vehicle. [Diagram 3] 2 is a plan view showing the configuration shown in FIG. 1 as viewed from above the vehicle. [Figure 4] 2 is a front view showing the configuration shown in FIG. 1 as viewed from the front of the vehicle. [Diagram 5] 5 is a front view showing the airbag in FIG. 4 in a see-through state. FIG. [Figure 6] FIG. 2 is an exploded view of the front and rear chambers shown in FIG. 1. [Figure 7] FIG. 2 is a development view of the airbag body shown in FIG. [Figure 8] FIG. 8 is an enlarged cross-sectional view taken along line 8-8 in FIG. 2. [Figure 9] 2 is a side cross-sectional view of the upper portion and surrounding area of ​​the seat back, showing a state before the airbag in FIG. 1 is inflated and deployed. [Figure 10] 2 is a side cross-sectional view of the upper portion and periphery of the seat back, showing a state immediately after the inflation and deployment of the airbag in FIG. 1 is completed. [Figure 11] 2 is a side view showing a state immediately after inflation and deployment of the airbag in FIG. 1 is completed. FIG. [Figure 12] 2 is a side view showing an initial state of restraining an occupant by the airbag of FIG. 1. [Figure 13] 2 is a side view showing a later stage of restraining an occupant by the airbag of FIG. 1. FIG. [Figure 14] 10 is a side cross-sectional view of the upper portion and periphery of a seat back in an occupant protection device according to a first modified example of the first embodiment, showing a state immediately after inflation and deployment of an airbag is completed. FIG. [Figure 15] 13 is a side cross-sectional view of the upper portion and periphery of a seat back in an occupant protection device according to a second modified example of the first embodiment, showing a state immediately after inflation and deployment of an airbag is completed. FIG. [Figure 16] FIG. 11 is a side view showing a state in which an airbag is inflated and deployed in an occupant protection device relating to a second embodiment, as viewed from the left side of the vehicle. [Figure 17] 17 is a side cross-sectional view of the upper portion and periphery of the seat back, showing a state before the airbag shown in FIG. 16 is inflated and deployed. FIG. [Figure 18] FIG. 17 is an exploded view of the front and rear chambers shown in FIG. 16. [Figure 19] 19 is an enlarged cross-sectional view taken along line 19-19 in FIG. 16. [Figure 20] 17 is a diagram illustrating a reinforcing sewn portion of the rear tether shown in FIG. 16. FIG. [Figure 21A] 17 is a diagram illustrating the direction of the grain of the front and rear extending portions shown in FIG. 16. FIG. [Figure 21B] 21B is a diagram showing a state in which the front-rear extending portion shown in FIG. 21A is stretched. FIG. [Figure 22A] FIG. 17 is a diagram for explaining the grain direction of the rear tether shown in FIG. 16. [Figure 22B] FIG. 20B shows the rear tether shown in FIG. 20A in a stretched state. [Diagram 23] 17 is a side view showing the state immediately after inflation and deployment of the airbag in FIG. 16 is completed. FIG. [Figure 24] 17 is a side view showing an initial state of restraining an occupant by the airbag of FIG. 16. FIG. [Diagram 25]17 is a side view showing a later stage of occupant restraint by the airbag of FIG. 16. FIG. [Figure 26] 13 is a diagram illustrating a reinforcing sewn portion of a rear tether in an occupant protection device according to a first modified example of the second embodiment. FIG. [Figure 27] 13 is a diagram illustrating a reinforcing sewn portion of a rear tether in an occupant protection device according to a second modified example of the second embodiment. FIG. [Figure 28] 13 is a diagram illustrating a reinforcing sewn portion of a rear tether in an occupant protection device according to a third modified example of the second embodiment. FIG. [Figure 29] 20 is a cross-sectional view corresponding to FIG. 19 showing a state in which the inflation and deployment of the airbag has been completed in the occupant protection device according to a fourth modified example of the second embodiment. FIG. [Diagram 30] 29 is a diagram illustrating a reinforcing sewn portion of the rear tether shown in FIG. 28. FIG. [Diagram 31] 13 is a diagram illustrating a reinforcing sewn portion of a rear tether in an occupant protection device according to a fifth modified example of the second embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0052] <First embodiment> An occupant protection device 10 according to a first embodiment of the present invention will be described below with reference to Figs. 1 to 13. In each drawing, some reference numerals may be omitted to make the drawing easier to see. Arrows FR, UP, LH, and RH, which are appropriately indicated in each drawing, respectively indicate the forward direction (traveling direction), upward direction, leftward direction, and rightward direction of the vehicle. In the following description, when the directions of front-rear, left-right, and up-down are simply used, they refer to front-rear in the front-rear direction of the vehicle, left-right in the left-right direction of the vehicle, and up-down in the up-down direction of the vehicle, unless otherwise specified.

[0053] As shown in Figs. 1 to 5, the passenger protection device 10 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). The vehicle seat 12 has a seat cushion 14, a seat back 16 erected above the rear end of the seat cushion 14, and a headrest 18 connected to the upper end of the seat back 16. The front-rear, left-right, top-bottom directions of the vehicle seat 12 coincide with the front-rear, left-right, top-bottom directions of the vehicle.

[0054] 1 to 5, a crash test dummy D is shown seated on a seat cushion 14 of a vehicle seat 12 as a model of an occupant (seater) to be protected. The dummy D is, for example, an AM50 (50th percentile of American adult males) frontal crash test dummy (Hybrid III). The dummy D is seated in a standard seating position defined by the crash test method, and the vehicle seat 12 is located at a reference setting position corresponding to the seating position. Hereinafter, for ease of understanding, the dummy D will be referred to as an "occupant D."

[0055] An 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 Figs. 1 to 3; not shown in Figs. 4 and 5) provided in a seat belt device 20. The seat belt device 20 is a three-point seat belt device, and is a so-called seat-mounted seat belt device in which a retractor, an anchor, and a buckle (reference numbers omitted) (not shown) are provided on the vehicle seat 12.

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

[0057] The airbag 32 receives gas supply from a pair of inflators 44 and inflates and deploys (deploys and inflates) from the rear side of the upper part of the vehicle seat 12 to the front 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 that inflate and deploy forward through both the left and right sides of the head H of the occupant D, and a connecting portion 34B that connects front ends of the pair of front / rear extending portions 34A in the left / right direction. The airbag body 40 inflates and deploys toward the occupant D side (rear side) behind the front / rear chambers 34 on 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 pieces of base fabric 36, 38 shown in FIG. 6 and sewing the peripheral parts at the sewing part S1. The airbag body 40 is formed into a bag shape by folding one piece of base fabric 42 shown in FIG. 7 along four folding lines L1, L2, L3, L4 and sewing at the sewing part S2. At the sewing part S2, the sewing line SL21 and the sewing line SL22 are sewn, the sewing line SL23 and the sewing line SL24 are sewn, the sewing line SL25 and the sewing line SL26 are sewn, and the sewing line SL27 and the sewing line SL28 are sewn. The base fabrics 36, 38, 42 shown in FIG. 6 and FIG. 7 are made of, for example, a nylon-based or polyester-based cloth material. One or both of the two pieces of base fabric 36, 38 constituting the front and rear chambers 34 are made of a base fabric less stretchable than the base fabric 42 constituting the airbag body 40.

[0059] As shown in Fig. 6, both longitudinal ends of the front and rear chamber 34 are formed as a pair of left and right inflator accommodating sections 34C that accommodate a pair of inflators 44. A longitudinal center section of the front and rear chamber 34 is formed as a connecting section 34B, and the sections between the connecting section 34B and the pair of inflator accommodating sections 34C are formed as front and rear extending sections 34A. As shown in Figs. 6 and 8, each of the pair of front and rear extending sections 34A is formed in a long tubular shape.

[0060] As shown in FIG. 6, the connecting portion 34B is in the shape of a substantially 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 FIG. 6 and FIG. 7) provided in the center of the connecting portion 34B. The sewing portion S3 is, for example, in the shape of a substantially inverted trapezoid. A communication hole 48 that communicates the inside of the connecting portion 34B with the inside of the airbag body 40 is formed on the inside of the sewing portion S3. The communication hole 48 is, for example, in the shape of a substantially inverted trapezoid. The communication hole 48 is composed of a through hole 50 formed in the base cloth 36 of the front and rear chambers 34 and a through hole 52 formed in the base cloth 42 of the airbag body 40.

[0061] The pair of inflators 44 are combustion-type or cold gas-type cylinder-type inflators, and generate gas when activated. The activation of these inflators 44 is controlled by a control device (not shown), and generates gas when the vehicle collides.

[0062] FIG. 9 shows a side cross-sectional view of the upper periphery of the seat back 16 before the airbag 32 is inflated and deployed. A pair of inflator housings 34C (see FIG. 6) housing a pair of inflators 44 are arranged separately on the left and right sides in the module case 46. Each inflator 44 is arranged with its axial direction aligned with the up-down direction of the seat back 16. Each inflator 44 is provided with, for example, a pair of upper and lower stud bolts. The pair of stud bolts penetrate the inflator housing 34C, the module case 46, and the frame of the seat back 16, and nuts are screwed onto each stud bolt. In this way, the inflator housing 34C, the inflator 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 manner, such as rolled or bellows-like, and housed in a module case 46. When the pair of inflators 44 are activated, gas is generated in the pair of inflator housing portions 34C.

[0064] As shown in Figs. 10 and 11, the gas generated in the pair of inflator housings 34C flows through the pair of front and rear extending portions 34A toward the connecting portion 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 extending portions 34A, the connecting portion 34B, and the airbag body 40. When the airbag 32 inflates and deploys, a tear line (not shown) formed on the module case 46 is configured to rupture under the inflation pressure of the airbag 32. As a result, the airbag 32 can inflate and deploy to the outside of the module case 46. As shown in Fig. 10, the pair of front and rear extending portions 34A inflate and deploy, so that the folded airbag body 40 and the connecting portion 34B pass between the head H of the occupant D and the roof of the vehicle (not shown).

[0065] As shown in FIG. 11, the pair of inflated and deployed front-rear extending portions 34A extend in the front-rear direction on both the left and right sides of the head H of the occupant D, and face the head H from both the left and right sides with a gap therebetween. The pair of front-rear extending portions 34A are pulled diagonally downward toward the rear by a pair of left and right rear tethers 54 (described later), and thus assume a posture inclined downward toward the front. The front ends of the pair of inflated and deployed front-rear extending portions 34A are connected in the left-right direction by the inflated and deployed connecting portion 34B. As shown in FIG. 3, the front-rear chamber 34 including the pair of front-rear extending portions 34A and the connecting portion 34B is inflated and deployed in a U-shape opening toward the rear in a plan view.

[0066] As shown in Figs. 1, 2, 4 and 5, the expanded portion 34B1 is provided at the left-right center of the inflated and deployed connecting portion 34B, and has a larger vertical dimension than both left and right ends of the connecting portion 34B. The expanded portion 34B1 protrudes downward from both left and right ends of the connecting portion 34B. The aforementioned communication hole 48 (see Fig. 6) is formed in the expanded portion 34B1. The communication hole 48 is located at the rear side of the left-right center of the inflated and deployed connecting portion 34B. Gas from the inflator 44 is supplied rearward through the communication hole 48 into the airbag body 40. As a result, the airbag body 40 is inflated and deployed toward the occupant D side (rear side) behind the front and rear chambers 34 behind the connecting portion 34B. The airbag body 40 passes through the gap between the head H of the occupant D and the roof of the vehicle (not shown) from the rear side to the front side due to the inflation and deployment of the front and rear chambers 34, and then inflates and deploys toward the rear side. The inflated and deployed airbag body 40 faces the head H, chest C, and abdomen B of the occupant D from the front side with a gap therebetween.

[0067] As shown in Figures 11 to 13, the inflated and deployed airbag body 40 restrains, from the front side, an occupant D who moves forward due to inertial force caused by the impact of a vehicle collision. When the occupant is restrained, the front and rear chambers 34 are expanded in the front-rear direction, and the airbag body 40 is compressed in the front-rear direction. As shown in Figures 12 and 13, the airbag body 40 is shaped so as to be sandwiched between the thighs F and chest C of the occupant D when the occupant is restrained.

[0068] 1 to 4, 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 each formed in a long strip shape from a cloth material such as a nylon or polyester material.

[0069] One end of each of the pair of rear tethers 54 is respectively anchored to a longitudinal middle portion of the pair of front and rear extending portions 34A. In detail, as shown in Figs. 2 and 8, one end of each of the pair of rear tethers 54 is sewn together with the reinforcing cloth 62 to the front of the pair of front and rear extending portions 34A in a part of the sewn portion S1 at a position overlapping with the airbag body when inflation and deployment are completed in a side view of the seat. Note that the airbag 32 does not have to include the reinforcing cloth 62. The airbag 32 may also include a plurality of reinforcing cloths. Furthermore, for example, one end of each of the pair of rear tethers 54 may be sewn to an extending portion configured to be wider than other seam allowance portions of the front and rear chambers 34.

[0070] 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 engaged with the pretensioner mechanisms 64 in the seat back 16. As an example, the pretensioner mechanism includes a spool (not shown) that winds up the rear tether 54. Note that the pretensioner mechanism is not limited to this, and may be, for example, a mechanism including a cylinder and a piston that moves within the cylinder.

[0071] 1, 9 and 10, a pair of left and right slits 16A extending in the up-down direction of the seat are formed in the seat back 16. The pair of slits 16A are disposed on both sides of the seat in the left-right direction of the occupant D. As shown in Fig. 9, a portion of each of a pair of rear tethers 54 is inserted into the pair of slits 16A before the airbag 32 is inflated and deployed.

[0072] Inside the pair of slits 16A, there are provided winding portions 60 around which the longitudinal intermediate portions of the pair of rear tethers 54 are wound from the front side. These winding portions 60 are fixed to a frame (not shown) of the seat back 16.

[0073] 10, when the front and rear chambers 34 inflate and deploy forward when the airbag 32 inflates and deploys, the pair of rear tethers 54, one end of which is sewn to the pair of front and rear extending portions 34A, are pulled out from within the pair of slits 16A and deploy forward. Because of this configuration, the deployment direction of the pair of rear tethers 54 can be regulated by the pair of slits 16A.

[0074] When the airbag 32 is inflated and deployed, the pair of rear tethers 54 extend in the front-rear direction below the pair of front-rear extending portions 34A. In this state, the pair of rear tethers 54 are inclined downward toward the rear after the airbag 32 has been inflated and deployed, for example, after a predetermined time has elapsed since the inflator 44 was activated or a collision was detected or predicted (see arrow P1 in FIG. 11).

[0075] As described above, the pair of front and rear extensions 34A are retracted, so that when the airbag 32 restrains the occupant, the lower surfaces of the pair of front and rear extensions 34A come into contact with the left and right shoulders K of the occupant D (see Figs. 12 and 13). When the airbag 32 restrains the occupant, 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 when the occupant D is AM95 (the 95th percentile of American adult males) or AF05 (the 5th percentile of American adult females), the maximum length of the pair of rear tethers 54 and the length by 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 come into contact with 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 front of the upper part of the airbag body 40 that inflates and deploys above the front and rear chambers 34 to the front of the pair of front and rear extending parts 34A. One end of each of the pair of front upper tethers 56 is sewn to the left and right sides of the front of the upper part of the airbag body 40 that inflates and deploys above the front and rear chambers 34. The other end of each of the pair of front upper tethers 56 is sewn to the front of the pair of front and rear extending parts 34A. The pair of front upper tethers 56 suppress the airbag body 40 from excessively rotating upward around the connecting parts 34B when the airbag 32 is fully inflated and deployed.

[0077] The pair of front lower tethers 58 connect the left and right portions of the lower part of the airbag body 40 that inflates and deploys downward from the front and rear chambers 34 to the front portions of the pair of front and rear extending portions 34A. One end of each of the pair of front lower tethers 58 is sewn to the left and right portions of the lower part of the airbag body 40 that inflates and deploys downward from the front and rear chambers 34. The other end of each of the pair of front lower tethers 58 is sewn to the front portions of the pair of front and rear extending portions 34A. The pair of front lower tethers 58 suppress the airbag body 40 from excessively rotating downward about the connecting portions 34B when the airbag 32 is fully inflated and deployed.

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

[0079] When the control device detects or predicts a frontal collision based on information from the collision sensor, it activates the pair of inflators 44. Note that the types of frontal collisions for which the control device activates the inflators 44 include offset frontal collisions such as a diagonal collision and a minute overlap collision, in addition to a full-wrap frontal collision.

[0080] Furthermore, the control device is configured to activate the pretensioner mechanism 64 after the airbag 32 has been completely inflated and deployed. For example, the control device activates the pretensioner mechanism 64 after a predetermined time has elapsed since the activation of the inflator 44. Furthermore, the control device may activate the pretensioner mechanism 64 after a predetermined time has elapsed since the detection or prediction of a collision, for example.

[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 on which an occupant D sits, and an airbag device 30 that protects the occupant D in the event of a vehicle collision. According to this airbag device 30, gas generated from a pair of inflators 44 is supplied to an airbag 32 in the event of a vehicle collision, and the airbag 32 inflates and deploys from the seat rear side of an upper portion of the vehicle seat 12 to the seat front side.

[0083] At this time, the pair of left and right front and rear extensions 34A in the front and rear chamber 34 of the airbag 32 inflate and deploy toward the front side of the seat through the left and right sides of the head H of the occupant D seated in the vehicle seat 12. In addition, in the front and rear chamber 34, the connecting portion 34B connecting the front end portions of the pair of left and right front and rear extensions 34A in the left and right direction of the seat inflates and deploys after the pair of left and right front and rear extensions 34A. Furthermore, the airbag body 40 inflates and deploys toward the occupant D side on the seat rear side of the connecting portion 34B after the pair of left and right front and 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 expanding the front and rear extensions 34A in the front and rear direction of the seat. This compressive deformation of the airbag body 40 absorbs kinetic energy when the occupant moves due to inertia. In addition, the pair of left and right front and rear extensions 34A become a gas flow path and receive the load applied to the airbag body 40 from the occupant D to provide support.

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

[0085] In particular, according to the airbag device 30 of this embodiment, after the airbag 32 has been inflated and deployed, for example, after a predetermined time has elapsed since the inflator 44 was activated or a collision was detected or predicted, the pair of left and right pretensioner mechanisms 64 provided on the seat back 16 are activated and the pair of left and right rear tethers 54 are retracted. As a result, when the airbag 32 restrains an occupant, the pair of left and right front and rear extensions 34A are relatively retracted diagonally downward toward the rear of the seat by the pair of left and right rear tethers 54, so that the connecting portion 34B approaches the thighs F of the occupant D. At this time, the airbag body 40 inflated and deployed on the seat rear side of the connecting portion 34B rotates so as to fall toward the front side of the seat. Therefore, the airbag body 40 penetrates deeply between the thighs F and chest C of the occupant D, and the contact area between the occupant D and the airbag body 40 increases. This suppresses the airbag body 40 from being lifted up.

[0086] Here, if the rear tether 54 is too short throughout, the airbag 32 will be pulled downward when inflated and deployed, interfering with the head H of the occupant D, and there is a risk that the airbag 32 will not be able to pass between the head H and the roof of the vehicle (not shown). On the other hand, if the rear tether 54 is too long throughout, while the airbag 32 will be able to easily pass over the head of the occupant D when inflated and deployed, there is a risk that the airbag body 40 will be lifted when the occupant is restrained, reducing the contact area between the occupant D and the airbag 32, and that the airbag 32 will slip out above the head of the occupant D.

[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 been inflated and deployed. Therefore, the length of the pair of left and right rear tethers 54 in the vehicle front-rear 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 inflated and deployed. Therefore, 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 inflated and deployed, and retracting the rear tether 54 by the pretensioner mechanism 64 after the airbag 32 has been inflated and deployed, it is possible to achieve both ease of deployment of the airbag 32 and stability in restraining the occupant D.

[0088] Furthermore, according to the airbag device 30 of this embodiment, the pair of left and right rear tethers 54 are retracted by a pair of pretensioner mechanisms 64 arranged symmetrically on the left and right, so that the rocking movement of the airbag 32 in the up-down direction and the fore-and-aft direction of the seat at the completion of inflation and deployment can be effectively suppressed in a balanced manner.

[0089] Furthermore, according to the airbag device 30 of this embodiment, the airbag body 40 at the completion of inflation and deployment faces the head H, chest C, and abdomen B of the occupant D from the front side with a gap therebetween. Therefore, the airbag body 40 is inflated and deployed without interfering with the head H, chest C, and abdomen B of the occupant D. Furthermore, when the occupant D is restrained, the airbag body 40 can bring the upper body of the occupant D, including the head H, chest C, and abdomen B of the occupant D, into contact with the airbag body 40 over a wide area, thereby effectively reducing the load applied from the airbag body 40 to the occupant D.

[0090] Furthermore, according to the airbag device 30 of this embodiment, when an occupant is restrained, the pair of left and right front and rear extending portions 34A are pulled diagonally downward toward the rear of the seat by the pair of left and right rear tethers 54, so that the lower surfaces of the pair of left and right front and rear extending portions 34A come into contact with the left and right shoulders K of the occupant D. This makes it possible to stabilize the position of the airbag body 40 with respect to the head H of the occupant D in the vertical direction of the seat, regardless of the physique of the occupant D.

[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 portions of the pair of left and right front-rear extending portions 34A at positions that overlap with the airbag body 40 when inflation and deployment are complete in a side view of the seat, so that the connecting portion 34B can be brought closer to the thighs F of the occupant D even more effectively.

[0092] Furthermore, according to the airbag device 30 of this embodiment, the pair of left and right front and rear chambers 34 are formed into a bag shape by sewing the peripheral portions of two overlapping base fabrics at the sewing portion S1, and the pair of left and right rear tethers 54 are sewn to the pair of left and right front and rear extending portions 34A at parts of the sewing portion S1. Therefore, compared with the case where the pair of left and right rear tethers 54 are sewn to the pair of left and right front and rear extending portions 34A at positions other than the sewing portion S1, the pair of left and right rear tethers 54 can be engaged with the pair of left and right front and rear extending portions 34A with a simple configuration. In addition, the reinforcing cloth 62 can improve the strength of the portion where the pair of left and right rear tethers 54 are sewn to the pair of left and right front and rear extending portions 34A.

[0093] [Supplementary explanation of the first embodiment] In the above first embodiment, the pretensioner mechanism 64 has been described as being provided inside both the left and right sides of the seat back 16, but the pretensioner mechanism 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 a slit.

[0094] (First Modification) 14, the pretensioner mechanism 64 may be provided inside the module case 46. In the following modifications and embodiments, the same components as those in the first embodiment are denoted by the same reference numerals and descriptions thereof will be omitted as appropriate.

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

[0096] (Second Modification) Furthermore, like an airbag device 67 according to a second modified example shown in Fig. 15, the pretensioner mechanism 64 may be fixed to the vehicle body (not shown). As an 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 parts of the pair of rear tethers 54 are wound around the winding part 60 from below. As shown in Fig. 15, when the airbag 32 is inflated and deployed, the pair of rear tethers 54 are bent at the parts wound around the pair of winding parts 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 Fig. 16 to Fig. 25. As shown in Fig. 16, the occupant protection device 66 includes a vehicle seat 12 and an airbag device 70.

[0098] The airbag device 70 includes an airbag 72, a pair of inflators 44 (see FIG. 17), and a module case 46. The airbag 72 is normally stored in a folded state together with the pair of inflators 44 in the module case 46.

[0099] The airbag 72 receives gas from the pair of inflators 44 and inflates and deploys (deploys and inflates) from the rear side of the upper part of the vehicle seat 12 to the front side. The airbag 72 has a front-rear chamber 74 and an airbag body 40. The front-rear chamber 74 has a pair of left and right front-rear extending portions 74A that inflate and deploy forward through the left and right sides of the head H of the occupant D, and a connecting portion 74B that connects the front end portions of the pair of front-rear extending portions 74A in the left-right direction. Both ends in the longitudinal direction of the front-rear chamber 74 are a pair of left and right inflator housing portions 74C (see FIG. 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-rear chamber 74 on the rear side of the connecting portion 74B.

[0100] 18, the front and rear chambers 74 are formed into a long bag shape by overlapping two long pieces of base fabric 78, 80 and sewing the peripheral edges at a sewing section S1. The two pieces of base fabric 78, 80 are made of a nylon-based cloth material that is easily stretchable.

[0101] Here, as shown in FIG. 16, 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 are attached to the airbag 72. One end of each of the pair of rear tethers 76 is respectively anchored to a longitudinal middle portion of a pair of front and rear extending portions 74A. In detail, one end of each of the pair of rear tethers 76 is sewn to the pair of front and rear extending portions 74A at a position where the pair of rear tethers 76 overlaps with the airbag body when the inflation and deployment is completed in a side view of the seat. As shown in FIG. 18, the front and rear chambers 74 include an extending portion 75. The extending portion 75 is formed into a substantially trapezoidal shape by extending each of the two base fabrics 78, 80 to one side in the width direction. One end of each of the pair of rear tethers 76 is sewn to a sewing portion S4 provided on the extending portion 75. That is, one end of each of the pair of rear tethers 76 is sewn to the pair of front and rear extending portions 74A at a sewn portion S4 that is provided in the seam of the sewn portion S1 and is separate from the sewn portion S1. This makes it possible to suppress a load from being applied to the sewn portion S1 when the front and rear extending portions 34A are pulled by the rear tether 54.

[0102] 19, the pair of rear tethers 76 includes two long strip-shaped cloth materials 76A, 76B. The cloth materials 76A, 76B are made of, for example, PET (polyethylene terephthalate), which is difficult to stretch.

[0103] As shown in FIG. 17, the other end of each of the rear tethers 54 is secured to a pair of left and right fixing portions 81 provided inside the left and right side portions of the seat back 16, respectively.

[0104] As shown in Fig. 20, the two pieces of cloth material 76A, 76B constituting the pair of rear tethers 76 each include a pair of sewn portions 82 sewn continuously in a straight line along the longitudinal direction at both ends in the lateral direction, a pair of sewn portions 84 sewn continuously in a straight line in the longitudinal direction parallel to the sewn portions 82 on the inner side of the lateral direction of the rear tether 76 relative to the pair of sewn portions 82, and a plurality of sewn portions 86 provided at intervals in the longitudinal direction of the rear tether 76 between the pair of sewn portions 84. In this embodiment, these sewn portions 82, 84, 86 correspond to the reinforcing sewn portions of the present invention. The sewn portions 82, 84, 86 make it difficult for the pair of rear tethers 76 to stretch in the longitudinal direction.

[0105] Each of the multiple sewn portions 86 includes a sewn portion 86A sewn in a rectangular shape and an X-shaped sewn portion 86B sewn diagonally to the sewn portion 86 A. The multiple sewn portions 86 are arranged in the longitudinal direction at intervals that are approximately the same as or greater than the longitudinal dimension of each sewn portion 86.

[0106] As shown in Fig. 21A, the pair of front-rear extending portions 74A each have a diagonal grain relative to the longitudinal direction, so that, as shown in Fig. 21B, when a tensile load is applied along the longitudinal direction of the front-rear extending portions 74A, the front-rear extending portions 74A are stretched well.

[0107] On the other hand, as shown in Fig. 22A, the pair of rear tethers 76 each have a fabric grain parallel to the longitudinal direction. As a result, as shown in Fig. 22B, even if 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 extending portions 74A. In other words, the pair of rear tethers 76 are less likely to stretch than the pair of front and rear extending portions 74A due to the direction of the fabric grain.

[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 on which an occupant D sits, and an airbag device 70 that protects the occupant D in the event of a vehicle collision. According to this airbag device 70, gas generated from a pair of inflators 44 is supplied to an airbag 72 in the event of a vehicle collision, and the airbag 72 inflates and deploys from the seat rear side of an upper portion of the vehicle seat 12 to the seat front side.

[0110] As shown in FIG. 23, the pair of left and right front-rear extending portions 74A in the front-rear chamber 74 of the airbag 72 inflate and deploy toward the front side of the seat by passing through both the left and right sides of the head H of the occupant D seated in the vehicle seat 12. In addition, in the front-rear chamber 74, the connecting portion 74B connecting the front ends of the pair of left and right front-rear extending portions 74A in the left-right direction of the seat inflates and deploys after the pair of left and right front-rear extending portions 74A. Furthermore, the airbag body 40 inflates and deploys toward the occupant D on the seat rear side of the connecting portion 74B after the pair of left and right front-rear extending portions 74A. As shown in FIG. 24 and FIG. 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 expanding the front-rear extending portions 74A in the front-rear direction of the seat. This compressive deformation of the airbag body 40 absorbs kinetic energy when the occupant D moves due to inertia. Further, the pair of left and right front and rear extending portions 74A serve as gas passages and also receive the load applied to the airbag body 40 by the occupant D, thereby providing support.

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

[0112] In particular, according to the airbag device 70 of this embodiment, the pair of rear tethers 76 are made of two overlapping cloth materials 76A, 76B sewn together, so that they are less likely to stretch than when they are made of a single cloth material. In addition, the pair of rear tethers 76 are made of a material that is less likely to stretch than the pair of front-rear extending portions 74A, so that they are even more difficult to stretch. Furthermore, the pair of rear tethers 76 are sewn by sewing portions 82, 84, 86 that are at least partially provided along the longitudinal direction, so that they are even more difficult to stretch in the longitudinal direction. Furthermore, while the pair of front-rear extending portions 74A have a fabric grain that is oblique to the longitudinal direction, the pair of rear tethers 76 have a fabric grain that is parallel to the longitudinal direction. Therefore, the pair of rear tethers 76 are even more difficult to stretch in the longitudinal direction.

[0113] As described above, since the pair of rear tethers 76 are difficult to stretch in the longitudinal direction, when the airbag 72 restrains the occupant, the pair of front and rear extending portions 74A are relatively pulled in diagonally downward toward the rear of the seat by the pair of rear tethers 76, and the connecting portion 74B approaches the thighs of the occupant. At this time, the airbag body 40, which is inflated and deployed on the seat rear side of the connecting portion 74B, rotates so as to fall toward the front side of the seat. Therefore, the airbag body 40 penetrates deeply between the thighs F and chest C of the occupant D, and the contact area between the occupant D and the airbag 32 increases. This suppresses the airbag body 40 from being lifted up.

[0114] Furthermore, the sewn portions 82, 84 are provided continuously in the longitudinal direction of the pair of rear tethers 76. This effectively prevents the pair of rear tethers 76 from stretching in the longitudinal direction.

[0115] Furthermore, a plurality of sewn portions 86 are provided at intervals in the longitudinal direction of the pair of rear tethers 76. In other words, in the pair of rear tethers, portions where the sewn portions 86 are provided and portions where the sewn portions 86 are not provided are alternately arranged along the longitudinal direction. This makes it easy to fold the pair of rear tethers 76, and allows the airbag to be stored compactly.

[0116] [Supplementary explanation of the second embodiment] In the above second embodiment, the other ends of the pair of rear tethers 76 are described as being respectively fastened to a pair of left and right fixing parts 81 provided inside the left and right side portions of the seat back 16, but this is not limited thereto. For example, the other ends of the pair of rear tethers 76 may be fastened to a pair of left and right fixing parts provided on the side surfaces of the left and right side portions of the seat back 16. In addition, the other ends of the pair of rear tethers 76 may be fastened to a fixing part provided on a vehicle body (not shown).

[0117] In the above second embodiment, the cloth material 76A and the cloth material 76B of the pair of rear tethers 76 are described as being sewn together at a pair of sewn portions 82, a pair of sewn portions 84, and a plurality of sewn portions 86, but this is not limited thereto. The rear tether may be sewn together at least a portion of which has a reinforcing sewn portion of various shapes along the longitudinal direction.

[0118] (First Modification) For example, as in a first modified example shown in FIG. 26, the cloth material 76A and the cloth material 76B of a pair of rear tethers 76 may be sewn together only by a pair of sewn portions 82 and a pair of sewn portions 84.

[0119] (Second Modification) 27, the cloth materials 76A and 76B of the pair of rear tethers 76 may be sewn together by a pair of sewn portions 82 and a pair of sewn portions 88 arranged at equal intervals between the pair of sewn portions 82. The pair of sewn portions 88 are sewn continuously in a straight line in the longitudinal direction at the center in the lateral direction of the rear tether 76. According to this modification, the pair of sewn portions 82 and the pair of sewn portions 88 (a total of four straight line sewn portions) are sewn at equal intervals in the lateral direction, so that stretching of the rear tether 76 in the longitudinal direction is more effectively suppressed.

[0120] (Third Modification) Furthermore, as in a third modified example shown in FIG. 28, the cloth materials 76A and 76B of a pair of rear tethers 76 may be sewn together by a pair of sewn portions 82 and a pair of sewn portions 90 that are arranged at equal intervals between the pair of sewn portions 82 and are provided at intervals in the longitudinal direction of the rear tether 76.

[0121] (Fourth Modification) Furthermore, as in a fourth modified example shown in Figures 29 and 30, the pair of rear tethers 92 may each be made of a single piece of fabric material. In the fourth modified example, the pair of rear tethers 92 are provided with a plurality of sewn portions 86 spaced apart in the longitudinal direction. In other words, the pair of rear tethers 76 are provided with seamless portions 94 that do not have any sewn portions between the plurality of sewn portions 86. The seamless portions 94 are easily folded. This makes it even easier to fold the pair of rear tethers 92.

[0122] (Fifth Modification) 31, a pair of rear tethers 92 each made of a single piece of fabric may have only one sewn portion 96 sewn in a straight line along the longitudinal direction at the center in the short side direction. This modification can suppress the longitudinal extension of the rear tether 92 with the simplest configuration.

[0123] [Supplementary explanation of the above embodiment] In the above first embodiment and each of the modified examples of the first embodiment, the pair of rear tethers 54 has been described as being made of one piece of cloth material. In the above second embodiment and the first to third modified examples of the second embodiment, the pair of rear tethers 76 has been described as being made of two pieces of cloth material 76A, 76B. In the above fourth and fifth modified examples of the second embodiment, the pair of rear tethers 92 has been described as being made of one piece of cloth material. This is not limiting, and the number of pieces of cloth material that make up the rear tether may be any number. Note that the more the number of pieces of cloth material, the more difficult it is for the rear tether to stretch.

[0124] In the first embodiment, the occupant protection device 10 is described in which the pair of front and rear extensions 34A are relatively pulled in diagonally downward toward the rear of the seat by pulling in the pair of rear tethers 54 with the pair of pretensioner mechanisms 64. Furthermore, in the second embodiment, the occupant protection device 66 is described in which the pair of front and rear extensions 74A are relatively pulled in diagonally downward toward the rear of the seat with the rear tether 76 configured to be difficult to stretch. However, the occupant protection device may include both a pretensioner mechanism and a difficult-to-stretch rear tether. For example, the rear tether 54 of the first embodiment may be replaced with the rear tether 76 of the second embodiment.

[0125] Regarding the above embodiment, the following supplementary notes are further disclosed.

[0126] (Appendix 1) an inflator that generates gas when the vehicle crashes; an airbag that is supplied with the gas and inflates and deploys from a rear side of an upper portion of a vehicle seat to a front side of the seat; A pair of left and right rear tethers connecting the airbag to a seat back of the vehicle seat or a vehicle body; having The airbag is a pair of left and right front and rear extending portions that inflate and deploy toward a front side of the seat through the left and right sides of the head of an occupant seated in the vehicle seat, and a connecting portion that connects front end portions of the pair of left and right front and rear extending portions in the left and right direction of the seat when inflation and deployment are completed; an airbag body that inflates and deploys toward the occupant on the seat rear side of the connecting portion after the front-rear chamber, and that is compressed so as to be sandwiched between the thighs and chest of the occupant while extending the front-rear extension portion in the seat front-rear direction when the occupant is restrained; Equipped with The pair of left and right rear tethers have one end portion fastened to the pair of left and right front and rear extending portions and the other end portion fastened to the seat back or the vehicle body, and are configured to relatively pull the pair of left and right front and rear extending portions obliquely downward toward the rear of the seat when the occupant is restrained, thereby bringing the connecting portion closer to the thighs of the occupant. An airbag device for a vehicle. (Appendix 2) A pair of left and right pretensioner mechanisms are provided on the seat back or the vehicle body to retract the pair of left and right rear tethers after the airbag is fully inflated and deployed. 2. A vehicle airbag device as described in claim 1. (Appendix 3) The pair of left and right pretensioner mechanisms are provided symmetrically on both left and right sides of the seat back. 3. A vehicle airbag device as described in appended claim 2. (Appendix 4) The longitudinal extensibility of the pair of left and right rear tethers is smaller than the longitudinal extensibility of the pair of left and right front and rear extending portions. The vehicle airbag device according to any one of claims 1 to 3. (Appendix 5) 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 and rear extending portions. 5. A vehicle airbag device as described in claim 4. (Appendix 6) The pair of left and right rear tethers have a fabric grain that is parallel to the longitudinal direction, and the pair of left and right front and rear extending portions have a fabric grain that is oblique to the longitudinal direction. 6. A vehicle airbag device according to claim 4 or 5. (Appendix 7) The pair of left and right rear tethers each have a reinforcing sewn portion sewn at least partially along the longitudinal direction. The vehicle airbag device according to any one of claims 4 to 6. (Appendix 8) The reinforcing sewn portion is provided continuously in the longitudinal direction of the pair of left and right rear tethers. 8. A vehicle airbag device as described in appendix 7. (Appendix 9) The reinforcing sewn portions are provided at intervals in the longitudinal direction of the pair of left and right rear tethers. 8. A vehicle airbag device as described in appendix 7. (Appendix 10) When the inflation and deployment is completed, the airbag body faces the head, chest, and abdomen of the occupant from the front side with a gap therebetween. The vehicle airbag device according to any one of claims 1 to 9. (Appendix 11) When the occupant is restrained, lower surfaces of the pair of left and right front and rear extending portions are configured to abut against left and right shoulders of the occupant. The vehicle airbag device according to any one of claims 1 to 10. (Appendix 12) The one end portions of the pair of left and right rear tethers are connected to front portions of the pair of left and right front-rear extending portions at positions overlapping with the airbag main body when the inflation and deployment are completed in a side view of the seat. The vehicle airbag device according to any one of claims 1 to 11. (Appendix 13) The pair of left and right front and rear chambers are formed into a bag shape by sewing the peripheral edges of two overlapping base fabrics at peripheral stitching parts, The pair of left and right rear tethers are sewn to the pair of left and right front and rear extending portions at parts of the peripheral stitching portion, respectively. The vehicle airbag device according to any one of claims 1 to 12. (Appendix 14) The pair of left and right rear tethers, together with the reinforcing cloth, are sewn to the two base cloths of the pair of left and right front and rear extending portions at the peripheral edge stitching portion. 14. The vehicle airbag device according to claim 13. (Appendix 15) A vehicle seat for a passenger to sit in; The vehicle airbag device according to any one of claims 1 to 14, which is mounted on a rear side of an upper portion of the vehicle seat; An occupant protection device comprising: [Explanation of symbols]

[0127] 10, 66 Occupant protection devices 12 Vehicle seats 16 Seat back 30, 65, 70 Airbag device 32, 72 Airbag 34, 74 Front and rear chambers 34A, 74A Front and rear extensions 34B, 74B connection part 36, 38, 78, 80 base fabric 40 Airbag body 44 Inflator 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 part (peripheral sewing part)

Claims

1. an inflator that generates gas when the vehicle crashes; an airbag that is supplied with the gas and inflates and deploys from a rear side of an upper portion of a vehicle seat to a front side of the seat; A pair of left and right rear tethers connecting the airbag to a seat back of the vehicle seat or a vehicle body; having The airbag is a pair of left and right front and rear extending portions that inflate and deploy toward a front side of the seat through the left and right sides of the head of an occupant seated in the vehicle seat, and a connecting portion that connects front end portions of the pair of left and right front and rear extending portions in the left and right direction of the seat when inflation and deployment are completed; an airbag body that inflates and deploys toward the occupant on the seat rear side of the connecting portion after the front-rear chamber, and that is compressed so as to be sandwiched between the thighs and chest of the occupant while extending the front-rear extension portion in the seat front-rear direction when the occupant is restrained; Equipped with The pair of left and right rear tethers have one end portion fastened to the pair of left and right front and rear extending portions and the other end portion fastened to the seat back or the vehicle body, and are configured to relatively pull the pair of left and right front and rear extending portions obliquely downward toward the rear of the seat when the occupant is restrained, thereby bringing the connecting portion closer to the thighs of the occupant. An airbag device for a vehicle.

2. A pair of left and right pretensioner mechanisms are provided on the seat back or the vehicle body to retract the pair of left and right rear tethers after the airbag is fully inflated and deployed.

2. The vehicle airbag device according to claim 1.

3. The pair of left and right pretensioner mechanisms are provided symmetrically on both left and right sides of the seat back.

3. The vehicle airbag device according to claim 2.

4. The longitudinal extensibility of the pair of left and right rear tethers is smaller than the longitudinal extensibility of the pair of left and right front and rear extending portions.

2. 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 stretchable than the pair of left and right front and rear extending portions.

5. The vehicle airbag device according to claim 4.

6. The pair of left and right rear tethers have a fabric grain that is parallel to the longitudinal direction, and the pair of left and right front and rear extending portions have a fabric grain that is oblique to the longitudinal direction.

5. The vehicle airbag device according to claim 4.

7. The pair of left and right rear tethers each have a reinforcing sewn portion sewn at least partially along the longitudinal direction.

5. The vehicle airbag device according to claim 4.

8. The reinforcing sewn portion is provided continuously in the longitudinal direction of the pair of left and right rear tethers.

8. The vehicle airbag device according to claim 7.

9. The reinforcing sewn portions are provided at intervals in the longitudinal direction of the pair of left and right rear tethers.

8. The vehicle airbag device according to claim 7.

10. When the inflation and deployment is completed, the airbag body faces the head, chest, and abdomen of the occupant from the front side with a gap therebetween.

2. The vehicle airbag device according to claim 1.

11. When the occupant is restrained, lower surfaces of the pair of left and right front and rear extending portions are configured to abut against left and right shoulders of the occupant.

11. The vehicle airbag device according to claim 10.

12. The one end portions of the pair of left and right rear tethers are connected to front portions of the pair of left and right front-rear extending portions at positions overlapping with the airbag main body when the inflation and deployment are completed in a side view of the seat.

2. The vehicle airbag device according to claim 1.

13. The pair of left and right front and rear chambers are formed into a bag shape by sewing the peripheral edges of two overlapping base fabrics at peripheral stitching parts, The pair of left and right rear tethers are sewn to the pair of left and right front and rear extending portions at parts of the peripheral stitching portion, respectively.

2. The vehicle airbag device according to claim 1.

14. The pair of left and right rear tethers, together with the reinforcing cloth, are sewn to the two base cloths of the pair of left and right front and rear extending portions at the peripheral stitching portion.

14. The vehicle airbag device according to claim 13.

15. A vehicle seat for a passenger to sit in; The vehicle airbag device according to any one of claims 1 to 14, which is mounted on a rear side of an upper portion of the vehicle seat; An occupant protection device comprising:

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