Vehicle airbag device and occupant protection device

Abstract

The invention provides a vehicle airbag device and an occupant protection device. This vehicle airbag device is provided with: an airbag which is inflated and deployed from the seat rear side to the seat front side of a vehicle seat; and a pair of left and right rear tethers that connect the airbag and the seat back of the vehicle seat or the vehicle body, the airbag being provided with: a pair of left and right front-rear extension sections that expand and deploy toward the front side of the seat through the left and right sides of the head of the occupant; a connecting part for connecting the front end parts of the pair of front-rear extension parts in the left-right direction of the seat; and an airbag main body that expands and deploys to the occupant side by delaying from the front and rear chambers at the seat rear side of the connecting part, and the pair of rear tethers are configured so that the pair of left and right front and rear extension parts are respectively and relatively pulled obliquely downward to the rear of the seat when the occupant is restrained, and the connecting part is brought close to the thighs of the occupant.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority from Japanese Patent Application No. 2023-132158 filed on August 14, 2023, the disclosure of which is incorporated herein by reference. Technical Field

[0003] The present disclosure relates to a vehicle airbag device and an occupant protection device. Background Art

[0004] An airbag device is disclosed in Japanese Patent Publication No. 2019-018593, which includes: an inflator that generates high-pressure gas when an impact is input; and a bag body (airbag) that is supplied with gas from the inflator and expands from the seat back of a vehicle seat. The bag body is constructed to include: a body support portion that expands from behind the head of a seated occupant to the front of the occupant; and a pair of head support portions that expand on the left and right sides of the occupant's head and are connected to the body support portion. In the technology described in Japanese Patent Publication No. 2019-018593, the expanded body support portion is connected to the seat or the vehicle body by a belt-shaped connecting member. As a result, the movement of the expanded body support portion is restricted by the connecting member.

[0005] In addition, Japanese Patent Publication No. 2019-218014 discloses an airbag device, which includes: an inflator; an airbag that is deployed by gas supplied from the inflator. The airbag includes a rear inflation portion that is deployed on the back side of the seat, a pair of side inflation portions that extend forward from the left and right sides of the rear inflation portion, and a pair of front inflation portions that extend from the side inflation portions to the central side and are connected to each other at the center to cover the front of the occupant. In addition, the airbag device described in Japanese Patent Publication No. 2019-218014 includes a belt-shaped connecting member that connects a pair of support points and the side inflation portions that are arranged on the front side of the seat and on the left and right sides of the seat.

[0006] In the technology described in Japanese Patent Application Publication No. 2019-018593 and Japanese Patent Application Publication No. 2019-218014, since the structure is to deploy the airbag from behind the occupant's head to the front of the head, if the connecting member is short, the airbag will be pulled to the lower side of the seat when the airbag is deployed, and it may not pass between the occupant's head and the roof of the vehicle. In addition, if the connecting member is long, although the airbag is easy to pass through the occupant's head when the airbag is deployed, it is possible that the airbag body rises when the occupant is restrained, thereby reducing the contact area between the occupant and the airbag, and the airbag retreats to the upper side of the occupant's head. In other words, there is still room for improvement in terms of balancing the ease of deployment of the airbag and the stability of occupant restraint. Summary of the invention

[0007] The present disclosure provides a vehicle airbag device capable of achieving both ease of deployment of an airbag and stability in restraining an occupant, and an occupant protection device including the vehicle airbag device.

[0008] The first mode of the vehicle airbag device comprises: an inflation device, which generates gas when the vehicle collides; an airbag, which is supplied with the gas and expands and deploys from the rear side of the seat to the front side of the seat at the upper part of the vehicle seat; a pair of left and right rear tethers, which connect the airbag to the seat back or the vehicle body of the vehicle seat, the airbag having: a front and rear chamber, which is constructed to include a pair of left and right front and rear extensions and a connecting portion, the pair of left and right front and rear extensions passing through the left and right sides of the head of the occupant sitting on the vehicle seat to expand and deploy toward the front side of the seat, the connecting portion connecting the front end portions of the pair of left and right front and rear extensions when the expansion and deployment is completed. The seat is connected in the left-right direction; the airbag body expands and deploys toward the occupant side at the rear side of the seat of the connecting portion with a delay from the front and rear chambers, and when the occupant is restrained, the front and rear extension portions are stretched in the front-to-rear direction of the seat and compressed in a manner of being sandwiched between the thighs and chest of the occupant, the left and right pair of rear straps are constructed so that each one end is clamped on the left and right pair of front and rear extension portions, and each other end is clamped on the seat back or the vehicle body, and when the occupant is restrained, the left and right pair of front and rear extension portions are relatively pulled toward the rear and obliquely downward of the seat so that the connecting portion is close to the thighs of the occupant.

[0009] According to the vehicle airbag device of the first embodiment, when the vehicle collides, the gas generated from the inflator is supplied to the airbag, so that the airbag expands and deploys from the rear side of the seat to the front side of the seat on the upper part of the vehicle seat. At this time, the left and right front and rear extensions in the front and rear chambers pass through the left and right sides of the head of the occupant sitting on the vehicle seat and expand and deploy to the front side of the seat. In addition, the airbag body expands and deploys to the occupant side at the rear side of the seat delayed from the front and rear chambers. When the occupant is restrained, the airbag body stretches the front and rear extensions in the front and rear directions of the seat and is compressed in a manner that is sandwiched between the thigh and chest of the occupant. The kinetic energy of the occupant during inertial movement is absorbed by the compression deformation of the airbag body. In addition, the left and right front and rear extensions become gas flow channels and bear the load applied to the airbag body from the occupant to become a supporting member. However, the "pulling to the rear and obliquely downward of the seat" mentioned here refers to a concept that widely includes the load applied to the left and right front and rear extensions in the rear and obliquely downward of the seat without raising the airbag body.

[0010] Here, the airbag is connected to the seat back of the vehicle seat or the vehicle body through a pair of left and right rear tethers. In more detail, one end of each of the left and right rear tethers is clamped to a pair of left and right front and rear extensions, and the other end of each is clamped to the seat back or the vehicle body. The left and right rear tethers, together with the front and rear chambers, bear the load applied to the airbag body by the occupant and become a supporting member. In addition, when the occupant is restrained by the airbag, the left and right front and rear extensions are relatively pulled toward the rear and lower side of the seat by the left and right rear tethers, so that the connection part is close to the thigh of the occupant. At this time, the airbag body that is inflated and deployed at the rear side of the seat of the connection part rotates in a manner that tilts toward the front side of the seat. Therefore, the airbag body will be deeply squeezed between the thigh and chest of the occupant, thereby increasing the contact area between the occupant and the airbag. As a result, the rise of the airbag body is suppressed.

[0011] A vehicle airbag device according to a second aspect is configured such that, in the first aspect, a pair of left and right pretensioner mechanisms for pulling the pair of left and right rear tethers after inflation and deployment of the airbag are completed are provided on the seat back or the vehicle body.

[0012] According to the second mode of the vehicle airbag device, after the airbag is inflated and deployed, the left and right pair of pretensioner mechanisms provided on the seat back or the vehicle body are operated, so that the left and right pair of rear tethers are pulled. The left and right pair of front and rear extensions are strongly pulled obliquely downward to the rear of the seat by the left and right pair of pretensioner mechanisms. In other words, the length of the left and right pair of rear tethers when the occupant is restrained by the airbag will be shorter than the length of the left and right pair of rear tethers when the airbag is inflated and deployed. Thus, the maximum length of the rear tethers when the airbag is inflated and deployed can be set longer. Therefore, the airbag can more easily pass through the narrow gap above the occupant's head, and the situation where the airbag body rises when the occupant is restrained can be effectively prevented.

[0013] A vehicle airbag device according to a third aspect is the device according to the second aspect, wherein the pair of left and right pretensioner mechanisms are provided symmetrically on both left and right side portions of the seat back.

[0014] According to the third aspect of the vehicle airbag device, since the pair of left and right rear tethers are pulled by a pair of pretensioner mechanisms symmetrically arranged on the left and right, the swaying of the airbag in the seat vertical direction and the seat front-rear direction when inflation and deployment are completed can be effectively suppressed with good balance.

[0015] A vehicle airbag device according to a fourth aspect is the vehicle airbag device according to the first aspect, wherein an elongation rate of the pair of left and right rear tethers in the longitudinal direction is smaller than an elongation rate of the pair of left and right front and rear extending portions in the longitudinal direction.

[0016] According to the vehicle airbag device of the fourth mode, when the airbag is inflated and deployed, the tensile load is mainly borne by the pair of left and right front and rear extensions and elongated. In addition, when the occupant is restrained by the airbag, the tensile load is dispersed by the pair of left and right front and rear extensions and the pair of left and right rear tethers that are difficult to elongate, thereby supporting the airbag body. The pair of left and right front and rear extensions that are easy to elongate further elongate in the long side direction as the upper body of the occupant tilts toward the front side of the seat. Here, the pair of left and right rear tethers that are difficult to elongate apply a load to the pair of left and right front and rear extensions obliquely downward to the rear of the seat. As a result, the airbag body rotates in a manner that tilts toward the front side of the seat and deforms into a wedge shape when the seat is viewed from the side. As a result, the contact area between the thigh of the occupant and the connecting part of the airbag is further increased, and the rise of the airbag body is suppressed. Therefore, the airbag can be easily passed through the narrow gap above the head of the occupant by a simple structure, and the rise of the airbag body is suppressed.

[0017] A vehicle airbag device according to a fifth aspect is, in the fourth aspect, wherein the pair of left and right rear tethers are made of a material that is less likely to stretch than the pair of left and right front and rear extending portions.

[0018] According to the vehicle airbag device of the fifth embodiment, the elongation of the pair of left and right rear tethers in the long-side direction can be set smaller than the elongation of the pair of left and right front and rear extensions in the long-side direction due to the difference in elongation of the material itself. Therefore, the airbag can be easily passed through the narrow gap above the head of the occupant with a simpler structure, and the airbag body is suppressed from rising.

[0019] A vehicle airbag device according to a sixth aspect is the vehicle airbag device according to the fourth aspect, wherein the pair of left and right rear tethers have fabric patterns parallel to the longitudinal direction, and the pair of left and right front and rear extending portions have fabric patterns inclined to the longitudinal direction.

[0020] According to the vehicle airbag device of the sixth aspect, the elongation rate of the pair of left and right rear tethers in the long-side direction can be set smaller than the elongation rate of the pair of left and right front and rear extensions in the long-side direction by the difference in the directions of the fabric grains. Therefore, the airbag can be easily passed through the narrow gap above the head of the occupant with a simpler structure, and the airbag body is prevented from rising.

[0021] A vehicle airbag device according to a seventh aspect is the vehicle airbag device according to the fourth aspect, wherein the pair of left and right rear tethers include a reinforcing sewn portion at least a portion of which is sewn along the longitudinal direction.

[0022] According to the vehicle airbag device of the seventh aspect, since at least a portion of the reinforcing sewn portion is sewn along the long-side direction of the pair of left and right rear tethers, the extension of the pair of left and right rear tethers in the long-side direction is suppressed. Therefore, the following excellent effect is achieved, namely, the airbag can be easily passed through the narrow gap above the head of the occupant with a simpler structure, and the rise of the airbag body is suppressed.

[0023] A vehicle airbag device according to an eighth aspect is the vehicle airbag device according to the seventh aspect, wherein the reinforcing sewn portion is provided continuously in the longitudinal direction of the pair of left and right rear tethers.

[0024] According to the vehicle airbag device of the eighth aspect, since the reinforcing sewn portion is provided continuously in the longitudinal direction of the pair of left and right rear tethers, it is possible to more effectively suppress the extension of the pair of left and right rear tethers in the longitudinal direction.

[0025] A vehicle airbag device according to a ninth aspect is the vehicle airbag device according to the seventh aspect, wherein a plurality of the reinforcing sewn portions are provided at intervals in the longitudinal direction of the pair of left and right rear tethers.

[0026] According to the vehicle airbag device of the ninth aspect, the portions with the reinforcement sewing portions and the portions without the reinforcement sewing portions are alternately arranged along the longitudinal direction of the pair of left and right rear tethers, thereby making it easy to fold the pair of left and right rear tethers, thereby enabling the airbag to be compactly stored.

[0027] A vehicle airbag device according to a tenth aspect is configured as follows: in the first aspect, the airbag body when the inflation and deployment are completed faces the head, chest, and abdomen of the occupant from the front side with a gap therebetween.

[0028] 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, the airbag body can make the upper body including the head, chest and abdomen of the occupant contact with the airbag body with a large area, so that the load applied to the occupant from the airbag body can be well reduced.

[0029] The vehicle airbag device of the eleventh aspect is configured as follows according to the tenth aspect, wherein lower surfaces of the pair of left and right front-rear extending portions abut against left and right shoulders of the occupant when the occupant is restrained.

[0030] According to the vehicle airbag device of the eleventh aspect, when the occupant is restrained by the airbag, the pair of left and right front and rear extensions are pulled obliquely downward to 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 extensions abut against the left and right shoulders of the occupant. Thus, the position of the airbag body relative to the occupant's head in the seat vertical direction can be stabilized regardless of the physique difference of the occupant.

[0031] The vehicle airbag device of the twelfth aspect is that in the first aspect, the one ends of the pair of left and right rear tethers are connected to the front portions of the pair of left and right front and rear extensions at positions overlapping the airbag body when the inflation and deployment are completed when viewed from the seat side.

[0032] According to the twelfth aspect of the vehicle airbag device, the pair of left and right rear tethers are connected to the front portions of the pair of left and right front and rear extensions at positions where they overlap with the airbag body when inflation and deployment are complete when viewed from the side of the seat, so that the connection portion can be effectively brought close to the thighs of the occupant.

[0033] The thirteenth mode of the vehicle airbag device is that in the first mode, the pair of left and right front and rear chambers are formed into a bag shape by sewing the peripheral portions of two overlapping base cloths together at a peripheral sewing portion, and the pair of left and right rear tethers are respectively sewn together with the pair of left and right front and rear extension portions at a portion of the peripheral sewing portion.

[0034] 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 extensions, respectively. Therefore, compared with the case where the pair of left and right rear tethers are sewn to the pair of left and right front and rear extensions at positions different from the peripheral sewn portions, the pair of left and right rear tethers can be clamped to the pair of left and right front and rear extensions with a simple structure, and the strength of the airbag can be maintained.

[0035] A vehicle airbag device according to a fourteenth aspect is the vehicle airbag device according to the thirteenth aspect, wherein the pair of left and right rear tethers are sewn together with the reinforcing cloth to the two base cloths of the pair of left and right front and rear extending portions at the peripheral edge sewn portion.

[0036] According to the vehicle airbag device of the fourteenth aspect, the strength of the portion where the pair of left and right rear tethers and the pair of left and right front-rear extensions are sewn together can be improved by the reinforcing cloth.

[0037] An occupant protection device according to a fifteenth aspect includes: a vehicle seat on which an occupant sits; and the vehicle airbag device according to any one of the first to fourteenth aspects mounted on a seat rear side of an upper portion of the vehicle seat.

[0038] According to the occupant protection device of the fifteenth embodiment, the gas generated from the inflator is supplied to the airbag when the vehicle collides, so that the airbag expands and deploys from the rear side of the seat to the front side of the seat on the upper part of the vehicle seat. At this time, a pair of left and right front and rear extensions in the front and rear chambers pass through the left and right sides of the head of the occupant sitting on the vehicle seat and expand and deploy to the front side of the seat. In addition, the airbag body expands and deploys to the occupant side at the rear side of the seat of the connecting part with a delay from the front and rear chambers. When the occupant is restrained, the airbag body stretches the front and rear extensions in the front and rear directions of the seat and is compressed in a manner of being sandwiched between the thighs and chest of the occupant. The kinetic energy of the occupant during inertial movement is absorbed by the compression deformation of the airbag body. In addition, the pair of left and right front and rear extensions serve as a flow path for the gas, and bear the load applied to the airbag body from the occupant and serve as a supporting member.

[0039] Here, the pair of left and right rear tethers together with the front and rear chambers bear the load applied to the airbag body by the occupant and thus serve as a supporting member. In addition, when the occupant is restrained by the airbag, the pair of left and right front and rear extensions are pulled obliquely downward to the rear of the seat by the pair of left and right rear tethers, so that the connection portion is close to the thigh of the occupant. As a result, the contact area between the occupant and the airbag is increased, thereby suppressing the rise of the airbag.

[0040] The vehicle airbag device of the first aspect has an excellent effect of being able to achieve both ease of deployment of the airbag and occupant restraint stability.

[0041] The vehicle airbag device of the second aspect has the excellent effect of being able to more easily allow the airbag to pass through a narrow gap above the head of an occupant and reliably preventing the airbag body from rising when the occupant is restrained.

[0042] The vehicle airbag device of the third aspect has the excellent effect of being able to effectively suppress the swaying of the airbag in the seat vertical direction and the seat front-rear direction when inflation and deployment are completed with good balance.

[0043] The vehicle airbag devices of the fourth to seventh aspects have the excellent effect of being able to achieve both ease of deployment of the airbag and occupant restraint stability with a simple structure.

[0044] The vehicle airbag device of the eighth aspect has the excellent effect of being able to more effectively suppress the extension of the pair of left and right rear tethers in the longitudinal direction.

[0045] The vehicle airbag device according to the ninth aspect has the excellent effect that the airbag can be stored compactly.

[0046] The vehicle airbag device of the tenth aspect has the excellent effect of suppressing interference between the airbag body and the head, chest and abdomen of the occupant during inflation and deployment, and of satisfactorily reducing the load applied to the occupant by the airbag body during occupant restraint.

[0047] 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 head of the occupant in the seat vertical direction regardless of differences in the physique of the occupant.

[0048] The vehicle airbag device of the twelfth aspect has the excellent effect of being able to effectively bring the connecting portion closer to the thigh of the occupant.

[0049] The vehicle airbag device of the thirteenth aspect has the excellent effect that the pair of left and right rear tethers can be locked to the pair of left and right front and rear extending portions with a simple structure, and the strength of the airbag can be maintained.

[0050] The vehicle airbag device of the fourteenth aspect has the excellent effect of being able to improve the strength of the airbag.

[0051] The occupant protection device of the fifteenth aspect has an excellent effect of being able to achieve both ease of deployment of an airbag mounted on a vehicle seat and stability of restraint of an occupant seated on the vehicle seat. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Exemplary embodiments of the present disclosure will be described in detail with reference to the following drawings, in which:

[0053] Figure 1 It is a perspective view showing a state where an airbag is inflated and deployed in the occupant protection device according to the first embodiment.

[0054] Figure 2 For the general Figure 1 The structure shown is a side view as viewed from the left side of the vehicle.

[0055] Figure 3 For the general Figure 1 The structure shown is a top view as viewed from above the vehicle.

[0056] Figure 4 For the general Figure 1 The structure shown is a front view as viewed from the front of the vehicle.

[0057] Figure 5 For Figure 4 The front view shows the airbag in a see-through state.

[0058] Figure 6 for Figure 1 Expanded view of the front and rear chambers shown.

[0059] Figure 7 for Figure 1 An expanded view of the airbag body is shown.

[0060] Figure 8 for Figure 2 An enlarged cross-sectional view of line 8-8.

[0061] Fig. 9 To express Figure 1 A side sectional view of the upper periphery of a seat back in a state before an airbag is inflated and deployed.

[0062] Fig.10 To express Figure 1 A side sectional view of the upper portion and the periphery of a seat back in a state immediately after inflation and deployment of an airbag is completed.

[0063] Fig.11 To express Figure 1 A side view of the airbag immediately after inflation and deployment.

[0064] Fig.12 To indicate by Figure 1 A side view of the initial state of occupant restraint achieved by the airbag.

[0065] Fig.13 To indicate by Figure 1A side view of a state in which the airbag achieves a late occupant restraint.

[0066] Fig.14 It is a side cross-sectional view of the upper portion and the periphery of a seat back showing a state immediately after inflation and deployment of an air bag in the occupant protection device according to the first modified example of the first embodiment.

[0067] Fig.15 It is a side cross-sectional view of the upper portion and the periphery of a seat back showing a state immediately after inflation and deployment of an air bag in an occupant protection device according to a second modified example of the first embodiment.

[0068] Fig.16 This is a side view showing a state in which an airbag is inflated and deployed in the occupant protection device according to the second embodiment, as viewed from the left side of the vehicle.

[0069] Fig.17 To express Fig.16 The figure is a side cross-sectional view of the upper periphery of the seat back in a state before the air bag is inflated and deployed.

[0070] Fig.18 for Fig.16 Expanded view of the front and rear chambers shown.

[0071] Fig.19 for Fig.16 An enlarged cross-sectional view of line 19-19.

[0072] Fig. 20 For Fig.16 A diagram illustrating the reinforced sewn portion of the rear tether shown.

[0073] Fig.21A For Fig.16 A diagram illustrating the direction of the grain of the front and rear extensions shown.

[0074] Fig. 21B To express Fig.21A The diagram shows a state where the front and rear extensions are elongated.

[0075] Fig.22A For Fig.16 A diagram illustrating the direction of the grain of the rear lace shown.

[0076] Fig. 22B To express Fig.22A The figure shows the state where the rear tether is stretched.

[0077] Fig.23 To express Fig.16 A side view of the airbag immediately after inflation and deployment.

[0078] Fig.24 To indicate by Fig.16 A side view of the initial state of occupant restraint achieved by the airbag.

[0079] Fig.25 To indicate by Fig.16 A side view of a state in which the airbag achieves a late occupant restraint.

[0080] Fig.26 It is a diagram for explaining a reinforced sewn portion of a rear tether in the occupant protection device according to the first modified example of the second embodiment.

[0081] Fig. 27 It is a diagram for explaining a reinforced sewn portion of a rear tether in an occupant protection device according to a second modified example of the second embodiment.

[0082] Fig.28 A diagram for explaining a reinforced sewn portion of a rear tether in an occupant protection device according to a third modified example of the second embodiment.

[0083] Fig.29 The state after the inflation and deployment of the airbag in the occupant protection device according to the fourth modified example of the second embodiment is completed. Fig.19 The corresponding cross-sectional view.

[0084] Fig.30 For Fig.28 A diagram illustrating the reinforced sewn portion of the rear tether shown.

[0085] Fig.31 It is a diagram for explaining a reinforced sewn portion of a rear tether in an occupant protection device according to a fifth modified example of the second embodiment. DETAILED DESCRIPTION

[0086] <First embodiment>

[0087] Below, refer to Figures 1 to 13 The occupant protection device 10 involved in the first embodiment of the present disclosure is described. In addition, in each figure, in order to facilitate observation of the drawings, some symbols are sometimes omitted. In addition, the arrow mark FR, arrow mark UP, arrow mark LH and arrow mark RH appropriately described in each figure respectively represent the front (travel direction), top, left and right of the vehicle. In the following, when only the front and back, left and right, and up and down directions are used for description, unless otherwise specified, it represents the front and back of the vehicle front and back direction, the left and right of the vehicle left and right direction, and the up and down of the vehicle up and down direction.

[0088] like Figures 1 to 5As shown, the occupant 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 (car). The vehicle seat 12 has a seat cushion 14, a seat back 16 erected on the upper side of 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, and down directions of the vehicle seat 12 are consistent with the front, rear, left, right, up, and down directions of the vehicle.

[0089] In addition, Figures 1 to 5 , a crash test dummy D, which is a model of an occupant (sitter) to be protected, is seated on the seat cushion 14 of the vehicle seat 12. The dummy D is, for example, an AM50 (50th percentile of American adult males) dummy (Hybrid III) for a frontal crash test. The dummy D is seated in a standard sitting posture prescribed by the crash test law, and the vehicle seat 12 is located at a reference setting position corresponding to the sitting posture. In the following, for ease of understanding, the dummy D is referred to as "occupant D".

[0090] The occupant D sitting on the seat cushion 14 of the vehicle seat 12 is secured by a seat belt 22 (see Figures 1 to 3 ;exist Figure 4 as well as Figure 5 The seat belt device 20 is a three-point seat belt device, and is a so-called seat belt device attached to the seat, in which a retractor, an anchor, and a buckle (symbols omitted) not shown are all provided on the vehicle seat 12.

[0091] like Fig. 9 As shown in FIG. 1 , the airbag device 30 includes an airbag 32, a pair of inflators 44, and a module housing 46. The airbag 32 is normally stored in the module housing 46 in a folded state together with the pair of inflators 44. The module housing 46 is formed in a hollow rectangular parallelepiped shape. The module housing 46 is arranged at the rear of the upper portion of the vehicle seat 12 (specifically, at the upper end of the seat back 16 and the rear of the headrest 18), and is fixed to the upper end of the seat back 16 or to a vehicle body (not shown).

[0092] The airbag 32 receives gas supply from a pair of inflators 44 and expands and deploys (expands and expands) from the rear side of the upper portion of the vehicle seat 12 to the front side. The airbag 32 includes a front and rear chamber 34 and an airbag body 40. The front and rear chamber 34 includes a pair of left and right front and rear extensions 34A that penetrate the left and right sides of the head H of the occupant D and expand and deploy to the front side, and a connecting portion 34B that connects the front end portions of the pair of front and rear extensions 34A in the left and right direction. The airbag body 40 expands and deploys to the occupant D side (rear side) at the rear side of the connecting portion 34B with a delay from the front and rear chamber 34.

[0093] The front and rear chambers 34 are connected by Figure 6 The two long base fabrics 36 and 38 are overlapped and the peripheral edges are sewn together at the sewing portion S1 to form a long bag shape. Figure 7 The base fabric 42 shown is folded along four fold lines L1, L2, L3, L4 and sewn together at a sewing portion S2 to form a bag shape. In the sewing portion S2, sewing lines SL21 and SL22 are sewn together, sewing lines SL23 and SL24 are sewn together, sewing lines SL25 and SL26 are sewn together, and sewing lines SL27 and SL28 are sewn together. Figure 6 as well as Figure 7 The base fabrics 36, 38, 42 shown are made of, for example, nylon or polyester fabrics. One or both of the two base fabrics 36, 38 constituting the front and rear chambers 34 are made of a fabric that is less likely to stretch than the base fabric 42 constituting the airbag body 40.

[0094] like Figure 6 As shown, the two ends of the front and rear chambers 34 in the longitudinal direction are set as a pair of left and right inflator storage parts 34C for storing a pair of inflators 44. The central part of the front and rear chambers 34 in the longitudinal direction is set as a connecting part 34B, and the space between the connecting part 34B and the pair of inflator storage parts 34C is set as a front and rear extension part 34A. Figure 6 as well as Figure 8 As shown, the pair of front and rear extension portions 34A are respectively formed into long tube shapes.

[0095] like Figure 6 As shown in FIG. 1 , the connecting portion 34B is formed into a substantially T-shaped bag shape communicating with each of the front and rear extension portions 34A. The connecting portion 34B is provided at a sewn portion S3 (see FIG. 1 ) provided at the center of the connecting portion 34B. Figure 6 as well as Figure 7) is sewn together with the airbag body 40. The sewn portion S3 is, as an example, in a substantially inverted trapezoidal shape. A connecting hole 48 is formed on the inner side of the sewn portion S3 to connect the inside of the connecting portion 34B with the inside of the airbag body 40. The connecting hole 48 is, as an example, in a substantially inverted trapezoidal shape. The connecting hole 48 is composed of a through hole 50 formed on the base fabric 36 of the front and rear chambers 34 and a through hole 52 formed on the base fabric 42 of the airbag body 40.

[0096] The pair of inflators 44 are cylinder-type inflators of combustion type or low-temperature gas type, and generate gas by operation. The operation of these inflators 44 is controlled by a control device (not shown), and gas is generated when the vehicle collides.

[0097] exist Fig. 9 FIG. 4 is a side cross-sectional view of the upper periphery of the seat back 16 before the airbag 32 is inflated and deployed. Figure 6 ) are separately arranged at the left and right sides in the module housing 46. Each inflator 44 is arranged with its axis direction along the vertical direction of the seat back 16. Each inflator 44 is provided with, for example, a pair of upper and lower stud bolts. The pair of stud bolts penetrates the inflator storage portion 34C, the module housing 46, and the frame of the seat back 16, and a nut is threadedly engaged with each stud bolt. Thus, the inflator storage portion 34C, the inflator 44, and the module housing 46 are fixed to the frame of the seat back 16.

[0098] The airbag 32 is normally folded in a predetermined folding manner such as roll folding or accordion folding and is stored in the module case 46. When the pair of inflators 44 are operated, gas is generated in the pair of inflator storage portions 34C.

[0099] like Fig.10 as well as Fig.11 As shown, the gas generated in the pair of inflator storage portions 34C flows through the pair of front and rear extensions 34A to the connecting portion 34B, and is supplied to the airbag body 40 through the connecting hole 48. As a result, the airbag 32 is inflated and deployed in the order of the pair of front and rear extensions 34A, the connecting portion 34B, and the airbag body 40. It is configured so that when the airbag 32 is inflated and deployed, the tear line (not shown) formed on the module housing 46 is ruptured by the inflation pressure of the airbag 32. As a result, the airbag 32 can be inflated and deployed to the outside of the module housing 46. As shown in FIG. Fig.10 As shown, the folded airbag body 40 and the connecting portion 34B are extended and expanded by the pair of front and rear extending portions 34A, thereby passing between the head H of the occupant D and the ceiling (not shown) of the vehicle.

[0100] like Fig.11 As shown, the pair of inflated front and rear extensions 34A extend in the front-to-rear direction at the left and right sides of the head H of the occupant D, and are opposed to the head H with gaps on both sides. The pair of front and rear extensions 34A are pulled backward and downward by the pair of left and right rear tethers 54 described later, so as to be inclined in a downward direction toward the front. The front ends of the pair of inflated front and rear extensions 34A are connected in the left-right direction by the inflated connecting portion 34B. Figure 3 As shown, the front and rear chamber 34 including a pair of front and rear extension portions 34A and a connecting portion 34B is inflated and deployed in a substantially "U" shape opening toward the rear in a plan view.

[0101] like Figure 1 , Figure 2 , Figure 4 as well as Figure 5 As shown in FIG. 1 , an expansion portion 34B1 having a larger size in the vertical direction than the left and right ends of the connecting portion 34B is provided at the left and right central portion of the expanded and expanded connecting portion 34B. The expansion portion 34B1 protrudes downward compared to the left and right ends of the connecting portion 34B. The aforementioned connecting hole 48 ( Figure 6 Reference). The connecting hole 48 is located at the rear side of the left-right center portion of the inflated and deployed connecting portion 34B. The gas from the inflator 44 is supplied to the airbag body 40 toward the rear through the connecting hole 48. As a result, the airbag body 40 is inflated and deployed toward the occupant D side (rear side) at the rear of the connecting portion 34B with a delay from the front and rear chambers 34. After the airbag body 40 passes through the gap between the head H of the occupant D and the ceiling of the vehicle (not shown) from the rear side to the front side due to the expansion and expansion of the front and rear chambers 34, it is inflated and deployed toward the rear side. The inflated and deployed airbag body 40 is opposed to the head H, chest C and abdomen B of the occupant D with a gap from the front side.

[0102] like Figures 11 to 13 As shown, the inflated and deployed airbag body 40 restrains the occupant D who moves forward by inertia due to the impact of the vehicle collision from the front side. During the occupant restraint, the front and rear chambers 34 expand in the front and rear directions, and the airbag body 40 compresses in the front and rear directions. Fig.12 as well as Fig.13 As shown, the airbag body 40 is shaped so as to be sandwiched between the thighs F and the chest C of the occupant D when the occupant is restrained.

[0103] Here, if Figures 1 to 4As shown, 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 mounted on the airbag 32. The rear tethers 54, the front upper tethers 56, and the front lower tethers 58 are formed of, for example, nylon or polyester fabric in a long strip shape.

[0104] One end of each of the pair of rear ties 54 is respectively locked to the middle portion of the pair of front and rear extensions 34A in the longitudinal direction. Figure 2 as well as Figure 8 As shown, one end of each pair of rear tethers 54 is sewn to the front of the pair of front and rear extensions 34A at a part of the sewing portion S1 together with the reinforcing cloth 62 at a position where the airbag body is overlapped when the airbag is inflated and deployed when viewed from the side of the seat. In addition, the airbag 32 may not include the reinforcing cloth 62. In addition, the airbag 32 may include a plurality of reinforcing cloths. Furthermore, for example, one end of each pair of rear tethers 54 may be sewn to the extension portion that is configured to be wider than the other seam head portions of the front and rear chambers 34.

[0105] like Fig.11 As shown in FIG. 1 , a pair of pretensioner mechanisms 64 are provided in the seat back 16. The pair of pretensioner mechanisms 64 are provided symmetrically at 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 at the seat back 16. As an example, the pretensioner mechanism includes a reel (not shown) for winding up the rear tethers 54. In addition, the pretensioner mechanism is not limited to this, and for example, it may be a mechanism including a cylinder and a piston moving in the cylinder.

[0106] like Figure 1 , Fig. 9 as well as Fig.10 As shown in FIG. 1 , a pair of left and right slits 16A extending in the seat vertical direction are formed on the seat back 16. The pair of slits 16A are arranged on both sides of the seat in the left and right direction of the occupant D. Fig. 9 As shown, in the state before the airbag 32 is inflated and deployed, a portion of each of the pair of rear tethers 54 is inserted through the pair of slits 16A, respectively.

[0107] The pair of slits 16A are each provided with a hooking portion 60 for hooking the longitudinal middle portions of the pair of rear tethers 54 from the front side. The hooking portions 60 are fixed to a frame (not shown) of the seat back 16.

[0108] like Fig.10As shown, when the airbag 32 is inflated and deployed, if the front and rear chambers 34 are inflated and deployed forward, the pair of rear tethers 54, each of which has one end sewn to the pair of front and rear extensions 34A, are pulled out from the pair of slits 16A and deployed forward. Since it is configured in this way, the deployment direction of the pair of rear tethers 54 can be restricted by the pair of slits 16A.

[0109] When the airbag 32 is inflated and deployed, the pair of rear tethers 54 extend in the front-to-rear direction below the pair of front-to-rear extensions 34A. In this state, the pair of rear tethers 54 are inclined to descend toward the rear. The pretensioner mechanism 64 is configured such that, after the airbag 32 is inflated and deployed, the pair of rear tethers 54 are pulled obliquely downward to the rear (see FIG. 1 ) after a predetermined time has passed since, for example, the inflator 44 is operated or a collision is detected or predicted. Fig.11 The arrow marks P1).

[0110] The pair of front and rear extensions 34A are pulled as described above, so that when the occupant is restrained by the airbag 32, the lower surfaces of the pair of front and rear extensions 34A abut against the left and right shoulders K of the occupant D (see FIG. Fig.12 as well as Fig.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 the present embodiment, the occupant D is AM50, but the maximum length of the pair of rear tethers 54 and the length of the rear tethers 54 pulled by the pretensioner mechanism 64 are set so that the lower surfaces of the pair of front and rear extensions 34A will contact the left and right shoulders K of the occupant D even when the occupant D is AM95 (95th percentile of American adult males) or AF05 (5th percentile of American adult females).

[0111] The pair of front upper tethers 56 connect the left and right sides of the front portion of the upper portion of the airbag body 40 that expands and deploys upward compared to the front and rear chambers 34 and 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 front portion of the upper portion of the airbag body 40 that expands and deploys upward compared to 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 suppress the excessive upward rotation of the airbag body 40 around the connection portion 34B when the inflation and deployment of the airbag 32 is completed.

[0112] The pair of front lower tethers 58 connect the left and right sides of the lower part of the airbag body 40 that expands and deploys downwardly compared to the front and rear chambers 34 and the front part of the pair of front and rear extensions 34A. One end of each pair of front lower tethers 58 is sewn to the left and right sides of the lower part of the airbag body 40 that expands and deploys downwardly compared to the front and rear chambers 34. The other end of each pair of front lower tethers 58 is sewn to the front part of the pair of front and rear extensions 34A. When the inflation and deployment of the airbag 32 is completed, the pair of front lower tethers 58 suppress the excessive downward rotation of the airbag body 40 around the connection part 34B.

[0113] The airbag device 30 is provided with a control device (ECU: Electronic Control Unit) (not shown) for controlling the operation of a pair of inflators 44. The control device is electrically connected to the pair of inflators 44 and a collision sensor (not shown). The control device is configured to detect or predict the occurrence of various types of frontal collisions (or situations where a frontal collision is unavoidable) applied to the automobile for each type of collision described later, based on information from the collision sensor.

[0114] When a frontal collision is detected or predicted based on information from the collision sensor, the control device activates the pair of inflators 44. In addition, the types of frontal collisions in which the control device activates the inflators 44 include eccentric frontal collisions such as oblique collisions and slight overlap collisions in addition to full overlap frontal collisions.

[0115] Furthermore, the control device operates the pretensioner mechanism 64 after the inflation and deployment of the airbag 32 is completed. For example, the control device operates the pretensioner mechanism 64 after a predetermined time has passed since the inflator 44 was operated. Furthermore, the control device may operate the pretensioner mechanism 64 after a predetermined time has passed since a collision was detected or predicted, for example.

[0116] (effect)

[0117] Next, the operation of the first embodiment will be described.

[0118] The occupant protection device 10 according to the present embodiment includes a vehicle seat 12 on which an occupant D is seated, and an airbag device 30 for protecting the occupant D in the event of a vehicle collision. According to the airbag device 30, gas generated from a pair of inflators 44 in the event of a vehicle collision is supplied to the airbag 32, and the airbag 32 is inflated and deployed from the seat rear side to the seat front side of the upper portion of the vehicle seat 12.

[0119] At this time, the pair of left and right front and rear extensions 34A in the front and rear chambers 34 of the airbag 32 pass through the left and right sides of the head H of the occupant D sitting on the vehicle seat 12 and expand toward the front side of the seat. In addition, in the front and rear chambers 34, the connecting portion 34B connecting the front ends of the pair of left and right front and rear extensions 34A in the left and right direction of the seat expands and expands later than the pair of left and right front and rear extensions 34A. Furthermore, the airbag body 40 expands and expands toward the occupant D side at the seat rear side of the connecting portion 34B later than the front and rear chambers 34. When restraining the occupant D, the airbag body 40 stretches the front and rear extensions 34A in the front and rear direction of the seat and is compressed in a manner to be sandwiched between the thigh F and the chest C of the occupant D. The kinetic energy of the occupant during inertial movement is absorbed by the compression deformation of the airbag body 40. In addition, the pair of left and right front and rear extensions 34A serve as a gas flow path and bear the load applied to the airbag body 40 from the occupant D, thereby serving as a supporting member.

[0120] Here, the airbag 32 is connected to the seat back 16 of the vehicle seat 12 through 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 engaged with a pair of left and right front and rear extensions 34A, and the other end of each of the pair of left and right rear tethers 54 is engaged with 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 serving as a supporting member.

[0121] In particular, according to the airbag device 30 of the present embodiment, after the inflation and deployment of the airbag 32 is completed, after a predetermined time has passed since, for example, the inflator 44 is operated or a collision is detected or predicted, the pair of left and right pretensioner mechanisms 64 provided in the seat back 16 are operated, and the pair of left and right rear tethers 54 are pulled. As a result, when the occupant is restrained by the airbag 32, the pair of left and right front and rear extensions 34A are relatively pulled obliquely downward to the rear of the seat by the pair of left and right rear tethers 54, so that the connection portion 34B approaches the thigh F of the occupant D. At this time, the airbag body 40 inflated and deployed at the seat rear side of the connection portion 34B rotates in a manner tilted toward the front side of the seat. Therefore, the airbag body 40 is deeply inserted between the thigh F and the chest C of the occupant D, and the contact area between the occupant D and the airbag body 40 is increased. As a result, the rise of the airbag body 40 is suppressed.

[0122] Here, if the rear tether 54 is too short from beginning to end, the airbag 32 will be pulled downward during inflation and deployment, interfering with the head H of the occupant D, and the airbag 32 may not be able to pass between the head H and the ceiling (not shown) of the vehicle. On the other hand, if the rear tether 54 is too long from beginning to end, the airbag 32 may easily pass through the head of the occupant D during inflation and deployment, but on the other hand, the airbag body 40 may rise during occupant restraint, resulting in a decrease in the contact area between the occupant D and the airbag 32, and the airbag 32 may retreat to the upper side of the occupant D's head.

[0123] In contrast, according to the airbag device 30 of the present embodiment, after the inflation and deployment of the airbag 32 is completed, the rear tether 54 is pulled by the pretensioner mechanism 64. Therefore, the length of the pair of left and right rear tethers 54 in the vehicle front-rear direction when the airbag 32 restrains 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 to a length that allows the airbag 32 to easily pass over the head of the occupant D when the airbag 32 is inflated and deployed, and by pulling the rear tether 54 by the pretensioner mechanism 64 after the inflation and deployment of the airbag 32 is completed, it is possible to achieve both the ease of deployment of the airbag 32 and the stability of restraining the occupant D.

[0124] In addition, according to the airbag device 30 involved in this embodiment, since the pair of left and right rear tethers 54 are pulled by a pair of pretensioner mechanisms 64 symmetrically arranged on the left and right, the swaying of the airbag 32 in the seat up-down direction and the seat front-back direction when inflation and deployment are completed can be effectively suppressed with good balance.

[0125] Furthermore, according to the airbag device 30 of the present embodiment, the airbag body 40 when inflated and deployed is opposed to the head H, chest C, and abdomen B of the occupant D with a gap from the front side. Therefore, the airbag body 40 is inflated and deployed in a manner that does not interfere with the head H, chest C, and abdomen B of the occupant D. In addition, when the occupant D is restrained, the airbag body 40 can make the upper body of the occupant D including the head H, chest C, and abdomen B of the occupant D contact the airbag body 40 with a large area, so that the load applied to the occupant D by the airbag body 40 can be well reduced.

[0126] Furthermore, according to the airbag device 30 of the present embodiment, since the pair of left and right front and rear extensions 34A are pulled obliquely downwardly and rearwardly of the seat by the pair of left and right rear tethers 54 when the occupant is restrained, the lower surfaces of the pair of left and right front and rear extensions 34A come into contact with the left and right shoulders K of the occupant D. Thus, regardless of the physique of the occupant D, the position of the airbag body 40 relative to the head H of the occupant D in the vertical direction of the seat can be stabilized.

[0127] In addition, according to the airbag device 30 involved in this embodiment, since the left and right pair of rear tethers 54 are connected to the front parts of the left and right pair of front and rear extension parts 34A at the position where they overlap with the airbag body 40 when inflation and deployment are completed when viewed from the side of the seat, the connecting part 34B can be more effectively brought closer to the thigh F of the occupant D.

[0128] Furthermore, according to the airbag device 30 involved in the present embodiment, the pair of left and right front and rear chambers 34 are formed into a bag shape by sewing the peripheral edge portions of the two overlapping base fabrics together at the sewing portion S1, and the pair of left and right rear tethers 54 are sewn together with the pair of left and right front and rear extensions 34A at a part of the sewing portion S1. Therefore, compared with the case where the pair of left and right rear tethers 54 are sewn together with the pair of left and right front and rear extensions 34A at a position different from the sewing portion S1, the pair of left and right rear tethers 54 can be clamped to the pair of left and right front and rear extensions 34A with a simple structure. In addition, the strength of the portion where the pair of left and right rear tethers 54 are sewn together with the pair of left and right front and rear extensions 34A can be improved by the reinforcement cloth 62.

[0129] [Supplementary explanation of the first embodiment]

[0130] Although the first embodiment has been described with reference to the case where the pretensioner mechanism 64 is disposed inside the left and right side portions of the seat back 16, the present invention is not limited thereto, and the pretensioner mechanism may be disposed outside the seat back. For example, the pretensioner mechanism may be fixed to the left and right side surfaces of the seat back. In this case, the seat back may not have a slit.

[0131] (First Modification Example)

[0132] In addition, if Fig.14 As in the airbag device 65 according to the first modification shown, 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 their description is omitted as appropriate.

[0133] In the first modification, when the front and rear chambers 34 expand and expand forward when the airbag 32 expands and expands, the pair of rear tethers 54 are pulled out from the module case 46 and pass through the pair of slits 16A and expand forward. Therefore, as in the first embodiment, the deployment direction of the pair of rear tethers 54 can be restricted by the pair of slits 16A.

[0134] (Second Modification Example)

[0135] Furthermore, if Fig.15 As in the airbag device 67 of the second modified example shown in FIG. 1 , 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 at the rear side of the seat back 16 and above the inflator 44. The middle part of the longitudinal direction of the pair of rear tethers 54 is wound around the winding portion 60 from the lower side. Fig.15 As shown, in the inflated and deployed state of the airbag 32, the pair of rear tethers 54 are bent at the hanging portions hung on the pair of hanging portions 60. In this embodiment as well, basically the same effects as those of the first embodiment can be obtained.

[0136] <Second embodiment>

[0137] Below, refer to Figures 16 to 25 The occupant protection device 66 according to the second embodiment of the present disclosure will be described. Fig.16 As shown, the occupant protection device 66 is configured to include the vehicle seat 12 and an airbag device 70 .

[0138] The airbag device 70 includes an airbag 72 and a pair of inflators 44 (see Fig.17 ), and a module case 46. The airbag 72 is normally housed in the module case 46 together with the pair of inflators 44 in a folded state.

[0139] The airbag 72 receives gas supply from a pair of inflators 44, and expands and deploys (expands and inflates) from the rear side of the upper portion of the vehicle seat 12 to the front side. The airbag 72 includes a front and rear chamber 74 and an airbag body 40. The front and rear chamber 74 includes a pair of left and right front and rear extension portions 74A that pass through the left and right sides of the head H of the occupant D and expand and deploy to the front side, and a connecting portion 74B that connects the front ends of the pair of front and rear extension portions 74A in the left and right directions. The two ends in the long side direction of the front and rear chamber 74 are provided as a pair of left and right inflator storage portions 74C (see FIG. 1 ) that store the pair of inflators 44. Fig.18 The airbag body 40 is inflated and deployed toward the occupant D side (rear side) at the rear side of the connection portion 74B with a delay from the front-rear chamber 74 .

[0140] like Fig.18 As shown, 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 peripheral edges together at a sewing portion S1. The two base fabrics 78 and 80 are made of nylon-like fabrics that are easily stretched.

[0141] Here, if Fig.16 As shown, 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 installed on the airbag 72. One end of each pair of rear tethers 76 is respectively locked in the middle part of the long side direction of the pair of front and rear extensions 74A. In detail, one end of each pair of rear tethers 76 is sewn to the pair of front and rear extensions 74A at a position where it overlaps with the airbag body when the expansion and deployment are completed when viewed from the side of the seat. Fig.18 As shown, the front and rear chambers 74 are provided with a protruding portion 75. The protruding portion 75 is formed into a substantially trapezoidal shape by protruding to one side in the width direction of the two base fabrics 78 and 80. One end of each pair of rear ties 76 is sewn to a sewing portion S4 provided on the protruding portion 75. That is, one end of each pair of rear ties 76 is sewn together with a pair of front and rear extensions 74A at a sewing portion S4 different from the sewing portion S1 provided on the seam head portion of the front and rear chambers 74. Thus, when the front and rear extensions 74A are pulled by the rear ties 76, the situation in which a load is applied to the sewing portion S1 can be suppressed.

[0142] like Fig.19 As shown, the pair of rear ties 76 is formed by two long strips of fabric 76A, 76B. As an example, the fabrics 76A, 76B are made of PET (polyethylene terephthalate) which is difficult to stretch.

[0143] like Fig.17 As shown, the other end portions of the rear tethers 76 are respectively locked to a pair of left and right fixing portions 81 provided inside the left and right side portions of the seat back 16 .

[0144] like Fig. 20 As shown, the two pieces of fabric 76A and 76B constituting the pair of rear ties 76 respectively include a pair of sewn portions 82 sewn linearly at both ends in the short-side direction in a manner continuous in the long-side direction, a pair of sewn portions 84 sewn linearly in the short-side direction inner side of the rear ties 76 relative to the pair of sewn portions 82 in a manner parallel to the sewn portions 82 and continuous in the long-side direction, and a plurality of sewn portions 86 provided at intervals in the long-side direction of the rear ties 76 between the pair of sewn portions 84. In the present embodiment, these sewn portions 82, 84, 86 correspond to the reinforcing sewn portions in the present disclosure. The sewn portions 82, 84, 86 make it difficult for the pair of rear ties 76 to extend in the long-side direction.

[0145] The plurality of sewn portions 86 are respectively configured to include a sewn portion 86A sewn in a rectangular shape and an X-shaped sewn portion 86B sewn on a diagonal line of the sewn portion 86A. The plurality of sewn portions 86 are arranged along the long side direction at intervals of a size substantially the same as or larger than the size of the long side direction of each sewn portion 86.

[0146] like Fig.21A As shown in FIG. 1 , the pair of front and rear extension portions 74A each have a fabric pattern inclined relative to the long side direction. Fig. 21B As shown, when a tensile load is applied along the longitudinal direction of the front-rear extending portion 74A, the front-rear extending portion 74A is well stretched.

[0147] On the other hand, Fig.22A As shown, the pair of rear ties 76 each have a fabric pattern parallel to the long side direction. Fig. 22B As shown, 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 extensions 74A. That is, the pair of rear tethers 76 are difficult to stretch compared to the pair of front and rear extensions 74A due to the direction of the fabric grain.

[0148] (effect)

[0149] Next, the operation of the second embodiment will be described.

[0150] The occupant protection device 66 according to the present embodiment includes a vehicle seat 12 on which an occupant D is seated, and an airbag device 70 for protecting the occupant D in the event of a vehicle collision. According to the 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 is inflated and deployed from the seat rear side to the seat front side of the upper portion of the vehicle seat 12.

[0151] like Fig.23 As shown, the pair of left and right front and rear extensions 74A in the front and rear chambers 74 of the airbag 72 pass through the left and right sides of the head H of the occupant D sitting on the vehicle seat 12 and expand toward the front side of the seat. In addition, in the front and rear chambers 74, the connecting portion 74B that connects the front ends of the pair of left and right front and rear extensions 74A in the left and right direction of the seat is expanded and expanded later than the pair of left and right front and rear extensions 74A. Furthermore, the airbag body 40 is expanded and expanded toward the occupant D side at the connecting portion 74B on the rear side of the seat later than the front and rear chambers 74. Fig.24 as well as Fig.25As shown, when the airbag body 40 restrains the occupant D, the front-rear extension portion 74A is stretched in the seat front-rear direction and compressed so as to be sandwiched between the thigh F and the chest C of the occupant D. The kinetic energy of the occupant D during inertial movement is absorbed by the compression deformation of the airbag body 40. In addition, the pair of left and right front-rear extension portions 74A serve as gas flow paths and as support members by receiving the load applied to the airbag body 40 from the occupant D.

[0152] 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 engaged with a pair of left and right front and rear extensions 74A, and the other end of each of the pair of left and right rear tethers 76 is engaged with the seat back 16. The pair of left and right rear tethers 76 together with the front and rear chambers receive the load applied to the airbag body 40 by the occupant D and serve as a supporting member.

[0153] In particular, according to the airbag device 70 involved in the present embodiment, since the pair of rear tethers 76 are formed by overlapping and sewing two pieces of cloth 76A and 76B, they are difficult to stretch compared with the case where they are formed by a single piece of cloth. In addition, since the pair of rear tethers 76 are formed by a material that is difficult to stretch compared with the pair of front and rear extensions 74A, they are more difficult to stretch. Furthermore, since the pair of rear tethers 76 are sewn using sewing portions 82, 84, and 86 that are at least partially provided along the long side direction, they are more difficult to stretch in the long side direction. Furthermore, compared with the pair of front and rear extensions 74A having a cloth grain that is inclined with respect to the long side direction, the pair of rear tethers 76 have a cloth grain that is parallel with respect to the long side direction. Therefore, the pair of rear tethers 76 are more difficult to stretch in the long side direction.

[0154] As described above, since the pair of rear tethers 76 are difficult to extend in the longitudinal direction, when the occupant is restrained by the airbag 72, the pair of front and rear extensions 74A are relatively pulled by the pair of rear tethers 76 toward the rear and lower sides of the seat, so that the connection portion 74B approaches the thigh of the occupant. At this time, the airbag body 40 that has been inflated and deployed at the seat rear side of the connection portion 74B rotates in a manner of tilting toward the seat front side. Therefore, the airbag body 40 deeply squeezes between the thigh F and chest C of the occupant D, thereby increasing the contact area between the occupant D and the airbag 32. As a result, the rise of the airbag body 40 is suppressed.

[0155] Furthermore, the sewn portions 82 and 84 are continuously provided in the longitudinal direction of the pair of rear tethers 76. Thus, the extension of the pair of rear tethers 76 in the longitudinal direction is effectively suppressed.

[0156] Furthermore, a plurality of sewn portions 86 are provided at intervals in the longitudinal direction of the pair of rear tethers 76. That is, on the pair of rear tethers, portions provided with sewn portions 86 and portions not provided with sewn portions 86 are alternately arranged along the longitudinal direction. Thus, the pair of rear tethers 76 can be easily folded, and the airbag can be compactly stored.

[0157] [Supplementary explanation of the second embodiment]

[0158] In the second embodiment, the other ends of the pair of rear tethers 76 are respectively locked to the pair of left and right fixing portions 81 provided inside the left and right side portions of the seat back 16, but the present invention is not limited thereto. For example, the other ends of the pair of rear tethers 76 may be locked to the pair of left and right fixing portions 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 locked to fixing portions provided on a vehicle body (not shown).

[0159] In addition, although the second embodiment described above describes a case where the fabrics 76A and 76B of the pair of rear ties 76 are sewn together at the pair of sewn portions 82, the pair of sewn portions 84, and the plurality of sewn portions 86, the present invention is not limited thereto. The rear ties can be sewn using reinforcing sewn portions of various shapes at least partially along the longitudinal direction.

[0160] (First Modification Example)

[0161] For example, Fig.26 As in the first modified example shown, the fabric 76A and the fabric 76B of the pair of rear ties 76 may be sewn together only by the pair of sewn portions 82 and the pair of sewn portions 84 .

[0162] (Second Modification Example)

[0163] In addition, if Fig. 27 As shown in the second modification example, the cloth 76A and the cloth 76B of the pair of rear ties 76 may be sewn together by a pair of sewing portions 82 and a pair of sewing portions 88 arranged at equal intervals between the pair of sewing portions 82. The pair of sewing portions 88 are sewn linearly in the middle portion of the short side direction of the rear ties 76 so as to be continuous in the long side direction. According to this modification example, since the pair of sewing portions 82 and the pair of sewing portions 88 (a total of four linear sewing portions) are sewn at equal intervals in the short side direction, the extension of the rear ties 76 in the long side direction is more effectively suppressed.

[0164] (Third Modification Example)

[0165] Further, if Fig.28As shown in the third modification example, the fabric 76A and the fabric 76B of a pair of rear ties 76 may be sewn together by a pair of sewing portions 82 and a plurality of pairs of sewing portions 90 which are arranged at equal intervals between the pair of sewing portions 82 and are spaced apart in the long side direction of the rear ties 76.

[0166] (Fourth Modification Example)

[0167] Furthermore, Fig.29 as well as Fig.30 As shown in the fourth modification example, the pair of rear ties 92 may be each made of a single piece of fabric. In the fourth modification example, the pair of rear ties 92 are provided with a plurality of sewn portions 86 spaced apart in the long side direction. In other words, the pair of rear ties 92 includes a non-sewn portion 94 between the plurality of sewn portions 86, and the non-sewn portion 94 does not include a sewn portion. The non-sewn portion 94 is easy to be folded. Thus, the pair of rear ties 92 is easier to fold.

[0168] (Fifth Modification)

[0169] In addition, if Fig.31 As shown in the fifth modification, the pair of rear ties 92 each made of one piece of fabric may have only one sewn portion 96, which is sewn linearly along the long side at the center of the short side. In this modification, the extension of the rear ties 92 in the long side direction can be suppressed with the simplest structure.

[0170] [Supplementary explanation of the above-mentioned embodiment]

[0171] In the first embodiment and each modification of the first embodiment, the case where the pair of rear ties 54 are each made of one piece of cloth is described. In addition, in the second embodiment and the first to third modifications of the second embodiment, the case where the pair of rear ties 76 are each made of two pieces of cloth 76A, 76B is described. Furthermore, in the fourth and fifth modifications of the second embodiment, the case where the pair of rear ties 92 are each made of one piece of cloth is described. Without being limited to this, the number of pieces of cloth constituting the rear ties may be any number of pieces. In addition, the greater the number of pieces of cloth, the more difficult it is for the rear ties to stretch.

[0172] In the first embodiment, the occupant protection device 10 is described in which the pair of rear tethers 54 are pulled by the pair of pretensioner mechanisms 64, thereby pulling the pair of front and rear extensions 34A relatively to the rear and downward of the seat. Furthermore, in the second embodiment, the occupant protection device 66 is described in which the pair of front and rear extensions 74A are pulled relatively to the rear and downward of the seat by the rear tether 76 that is difficult to stretch. This is not limiting, and the occupant protection device may also include both the pretensioner mechanism and the 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.

[0173] The following supplementary notes are further disclosed with respect to the above-mentioned embodiments.

[0174] (Note 1)

[0175] A vehicle airbag device, comprising:

[0176] an inflator, which generates gas in the event of a vehicle collision;

[0177] an airbag supplied with the gas and inflated and deployed from a seat rear side to a seat front side of an upper portion of a vehicle seat;

[0178] A pair of left and right rear tethers are provided to connect the airbag to a seat back of the vehicle seat or a vehicle body.

[0179] The airbag has:

[0180] a front and rear chamber, which is configured to include a pair of left and right front and rear extensions, the pair of left and right front and rear extensions passing through the left and right sides of the head of an occupant seated on the vehicle seat and expanding and unfolding toward the front side of the seat, and the connecting portion connecting the front end portions of the pair of left and right front and rear extensions when the expansion and unfolding is completed in the left and right direction of the seat;

[0181] an airbag body which expands and deploys toward the occupant side at a delay from the front and rear chambers at the seat rear side of the connecting portion, and when the occupant is restrained, the front and rear extension portions are stretched in the seat front and rear directions and compressed in a manner to be sandwiched between the thighs and chest of the occupant,

[0182] The pair of left and right rear straps are constructed so that each one end is clamped on the pair of left and right front and rear extensions, and each other end is clamped on the seat back or the vehicle body, and when the occupant is restrained, the pair of left and right front and rear extensions are pulled relatively toward the rear and downward of the seat, respectively, so that the connecting portion is close to the thigh of the occupant.

[0183] (Note 2)

[0184] The vehicle airbag device according to Supplementary Note 1, wherein a pair of left and right pretensioner mechanisms for pulling the pair of left and right rear tethers after the inflation and deployment of the airbag are completed are provided on the seat back or the vehicle body.

[0185] (Note 3)

[0186] The vehicle airbag device according to Supplementary Note 2, wherein the pair of left and right pretensioner mechanisms are provided symmetrically on both left and right side portions of the seat back.

[0187] (Note 4)

[0188] The vehicle airbag device according to any one of Supplementary Notes 1 to 3, wherein the elongation of the pair of left and right rear tethers in the longitudinal direction is smaller than the elongation of the pair of left and right front and rear extending portions in the longitudinal direction.

[0189] (Note 5)

[0190] The vehicle airbag device according to Supplementary Note 4, wherein the pair of left and right rear tethers are made of a material that is less likely to stretch than the pair of left and right front and rear extending portions.

[0191] (Note 6)

[0192] The vehicle airbag device as described in Supplementary Note 4 or Supplementary Note 5, wherein the pair of left and right rear tethers have fabric patterns parallel to the longitudinal direction, and the pair of left and right front and rear extending portions have fabric patterns inclined to the longitudinal direction.

[0193] (Note 7)

[0194] The vehicle airbag device according to any one of Supplementary Notes 4 to 6, wherein the pair of left and right rear tethers include a reinforcing sewn portion at least a portion of which is sewn along a longitudinal direction.

[0195] (Note 8)

[0196] The vehicle airbag device according to Supplementary Note 7, wherein the reinforcing sewn portion is provided continuously in the longitudinal direction of the pair of left and right rear tethers.

[0197] (Note 9)

[0198] The vehicle airbag device according to Supplementary Note 7, wherein a plurality of the reinforcing sewn portions are provided at intervals in the longitudinal direction of the pair of left and right rear tethers.

[0199] (Note 10)

[0200] The vehicle airbag device according to any one of Supplementary Notes 1 to 9, wherein the airbag body when the inflation and deployment are completed faces the head, chest, and abdomen of the occupant from the front side with a gap therebetween.

[0201] (Note 11)

[0202] The vehicle airbag device according to any one of Supplementary Notes 1 to 10, wherein the 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 when the occupant is restrained.

[0203] (Note 12)

[0204] A vehicle airbag device as described in any one of Notes 1 to 11, wherein each end portion of the pair of left and right rear tethers is connected to the front portion of the pair of left and right front and rear extension portions at a position where the end portion overlaps with the airbag body when the inflation and deployment are completed when viewed from the side of the seat.

[0205] (Note 13)

[0206] A vehicle airbag device as described in any one of Notes 1 to 12, wherein the pair of left and right front and rear chambers are formed into a bag shape by sewing the peripheral portions of two overlapping base cloths together at a peripheral sewing portion, and the pair of left and right rear tethers are sewn together with the pair of left and right front and rear extension portions at a portion of the peripheral sewing portion, respectively.

[0207] (Note 14)

[0208] The vehicle airbag device according to Supplementary Note 13, wherein the pair of left and right rear tethers are sewn together with the reinforcing cloth to the two base cloths of the pair of left and right front and rear extending portions at the peripheral edge sewn portion.

[0209] (Note 15)

[0210] An occupant protection device, comprising:

[0211] Seats for vehicles for seating occupants; and

[0212] The vehicle airbag device according to any one of Supplementary Notes 1 to 14 is mounted on a seat rear side of an upper portion of the vehicle seat.

Claims

1. A vehicle airbag device, comprising: an inflator, which generates gas in the event of a vehicle collision; an airbag supplied with the gas and inflated and deployed from a seat rear side to a seat front side of an upper portion of a vehicle seat; A pair of left and right rear tethers are provided to connect the airbag to a seat back of the vehicle seat or a vehicle body. The airbag has: a front and rear chamber, which is configured to include a pair of left and right front and rear extensions, the pair of left and right front and rear extensions passing through the left and right sides of the head of an occupant seated on the vehicle seat and expanding and unfolding toward the front side of the seat, and the connecting portion connecting the front end portions of the pair of left and right front and rear extensions when the expansion and unfolding is completed in the left and right direction of the seat; an airbag body which expands and deploys toward the occupant side at a delay from the front and rear chambers at the seat rear side of the connecting portion, and when the occupant is restrained, the front and rear extension portions are stretched in the seat front and rear directions and compressed in a manner to be sandwiched between the thighs and chest of the occupant, The pair of left and right rear straps are constructed so that each one end is clamped on the pair of left and right front and rear extensions, and each other end is clamped on the seat back or the vehicle body, and when the occupant is restrained, the pair of left and right front and rear extensions are respectively pulled relatively toward the rear and downward of the seat so that the connecting portion is close to the thigh of the occupant.

2. The vehicle airbag device according to claim 1, wherein: A pair of left and right pretensioner mechanisms for pulling the pair of left and right rear tethers after the inflation and deployment of the airbag is completed are provided on the seat back or the vehicle body.

3. The vehicle airbag device according to claim 2, wherein: The pair of left and right pretensioner mechanisms are disposed symmetrically on both left and right side portions of the seat back.

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

5. The vehicle airbag device according to claim 4, wherein: The pair of left and right rear tethers are made of a material that is less likely to stretch than the pair of left and right front and rear extending portions.

6. The vehicle airbag device according to claim 4, wherein: The pair of left and right rear ties have fabric grains parallel to the long side direction, and the pair of left and right front and rear extending portions have fabric grains inclined to the long side direction.

7. The vehicle airbag device according to claim 4, wherein: The pair of left and right rear tethers include a reinforcing sewn portion at least a portion of which is sewn along the longitudinal direction.

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

9. The vehicle airbag device according to claim 7, wherein: The reinforcement sewn portions are provided in plurality at intervals in the longitudinal direction of the pair of left and right rear tethers.

10. The vehicle airbag device according to claim 1, wherein: When the inflation and deployment are completed, the airbag main body faces the head, chest, and abdomen of the occupant from the front side with a gap therebetween.

11. The vehicle airbag device according to claim 10, wherein: The vehicle airbag device is configured such that, when the occupant is restrained, 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.

12. The vehicle airbag device according to claim 1, wherein: The one ends of the pair of left and right rear tethers are connected to the front portions of the pair of left and right front and rear extensions at positions where the airbag body overlaps with the airbag body when the inflation and deployment are completed when viewed from the side of the seat.

13. The vehicle airbag device according to claim 1, wherein: The pair of left and right front and rear chambers are formed into a bag shape by sewing the peripheral edges of the two overlapping base fabrics together at the peripheral sewing portion. The pair of left and right rear ties are respectively sewn together with the pair of left and right front and rear extending portions at a portion of the peripheral sewn portion.

14. The vehicle airbag device according to claim 13, wherein: The pair of left and right rear tethers are sewn together with the reinforcing cloth to the two base cloths of the pair of left and right front and rear extending portions at the peripheral sewn portion.

15. An occupant protection device comprising: Seats for vehicles for seating occupants; and A vehicle airbag device according to any one of claims 1 to 14 mounted on a seat rear side of an upper portion of the vehicle seat.

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