Seat-mounted airbag device

Abstract

To provide a seat-mounted airbag device capable of stabilizing deployment behavior of an airbag body which is inflated and deployed through between a head of an occupant and a ceiling of a cabin, and which is thereby disposed at a seat front side of the occupant.SOLUTION: A seat-mounted airbag device 30 comprises an airbag 32 comprising: front-rear chambers 34 which, when gas jetted from an inflator is supplied upon collision of a vehicle, are inflated and deployed forward through both left and right sides of a head of an occupant; and an airbag body 40 which, in association with inflation and deployment of the front-rear chambers 34, moves forward through between the head of the occupant and a ceiling of a cabin, and which, when the gas is supplied from the front-rear chambers 34, is inflated and deployed and is disposed at a front side of the occupant. In the airbag 32, the front-rear chambers 34 are stored in a headrest 18 while being bent downward relative to the airbag body 40. A jetting port 46A of the gas jetted from the inflator is located at a vertical direction center part at a rear side of each of the front-rear chambers 34.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present invention relates to a seat-mounted airbag device. [Background technology]

[0002] Airbag devices equipped with an airbag having a rear inflatable portion that deploys on the back side of the seat, a pair of side inflatable portions extending 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 have been known for some time (see, for example, Patent Document 1).

[0003] Also, an airbag device equipped with a bag body having a body support part that deploys from behind the occupant's head 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 body support part, is also known (see, for example, Patent Document 2). This bag body has a clearance part that, in the deployed state, penetrates in the vertical direction between the pair of head support parts to avoid the occupant's head. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-218013 A [Patent Document 2] JP 2019-018593 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the airbag device as described above, the airbag (bag body) is inflated and deployed from the seat back through the gap between the occupant's head and the ceiling, and is positioned in front of the occupant. However, if there is variation in the way the airbag is folded, the airbag that is about to inflate and deploy may swing up and down or left and right, causing an unstable deployment behavior.

[0006] Therefore, an object of the present invention is to provide a seat-mounted airbag device that can stabilize the deployment behavior of the airbag body located in front of the occupant's seat by inflating and deploying through the gap between the occupant's head and the ceiling of the vehicle compartment. [Means for solving the problem]

[0007] In order to achieve the above object, a seat-mounted airbag device of a first aspect of the present invention comprises an airbag having an inflator that is provided on a vehicle seat and ejects gas in the event of a vehicle collision, a pair of front and rear chambers that are supplied with the gas ejected from the inflator and that inflate and deploy toward the front side of the seat by passing through both the left and right sides of the head of an occupant seated in the vehicle seat, and an airbag body that moves toward the front side of the seat by passing between the head of the occupant and the ceiling of the vehicle compartment as the pair of front and rear chambers inflate and deploy toward the rear side of the seat between the pair of front and rear chambers by receiving the gas from the pair of front and rear chambers, and is disposed on the front side of the seat of the occupant, wherein, in a front view seen from the front side of the seat, the pair of front and rear chambers are folded toward the lower side of the seat with respect to the airbag body and stored in a headrest of the vehicle seat, and, in a side view seen from the seat width direction, an outlet of the gas ejected from the inflator is located in the vertical center of the pair of front and rear chambers on the rear side of the seat.

[0008] According to the first aspect of the invention, gas ejected from the inflator during a vehicle collision is supplied to the pair of front and rear chambers, which inflate and deploy toward the front of the seat by passing through both the left and right sides of the head of the occupant seated in the vehicle seat. The airbag body moves toward the front of the seat by passing between the head of the occupant seated in the vehicle seat and the ceiling of the vehicle cabin as the pair of front and rear chambers inflate and deploy toward the rear of the seat between the pair of front and rear chambers by being supplied with gas, and is positioned in front of the occupant's seat. Note that "during a collision" as used herein also includes a time when the inevitability of a collision is predicted (foreseen).

[0009] Here, in a front view of this airbag from the front side of the seat, a pair of front and rear chambers are folded toward the lower side of the seat relative to the airbag body and stored in the headrest of the vehicle seat, and in a side view from the width direction of the seat, the outlet for gas ejected from the inflator is located in the vertical center of the pair of front and rear chambers on the rear side of the seat.

[0010] Therefore, when the pair of front and rear chambers start to inflate and deploy, the vertical center portion of the pair of front and rear chambers on the seat rear side can be pushed toward the seat front side, and the deployment direction of the pair of front and rear chambers is stabilized. In other words, the deployment behavior of the airbag body arranged on the seat front side of the occupant is stabilized by inflating and deploying through the gap between the occupant's head and the ceiling of the vehicle compartment. Note that the "vertical center portion" referred to here includes a substantially vertical center portion that is slightly shifted from the center portion in the vertical direction.

[0011] A seat-mounted airbag device of a second aspect of the present invention is the seat-mounted airbag device of the first aspect, further comprising a distribution pipe that is provided on the vehicle seat and is capable of supplying gas ejected from the inflator to each of the pair of front and rear chambers, the distribution pipe having an outlet that is connected to a base portion of each of the pair of front and rear chambers, the outlet extending a predetermined length toward the front and upper side of the seat in a side view seen from the seat width direction, and being located in the vertical center of the pair of front and rear chambers on the seat rear side.

[0012] According to the second aspect of the invention, a vehicle seat is provided with a distribution pipe capable of supplying gas ejected from an inflator to a pair of front and rear chambers, and the distribution pipe has an outlet connected to the base of each of the pair of front and rear chambers. The outlet extends a predetermined length toward the front and upper side of the seat in a side view seen from the seat width direction, and is located in the vertical center of the pair of front and rear chambers on the seat rear side.

[0013] Therefore, when the pair of front and rear chambers start to inflate and deploy, the vertical center portion of the pair of front and rear chambers on the seat rear side can be pushed more effectively toward the seat front side, stabilizing the deployment direction of the pair of front and rear chambers. In addition, since the distribution pipe is provided, there are no restrictions on the mounting position of the inflator. Therefore, for example, the inflator can be mounted along the extension direction of the seat back, preventing the seat back from becoming larger (increasing in thickness). Note that the "vertical center portion" referred to here also includes a substantially vertical center portion that is slightly shifted from the center portion in the vertical direction.

[0014] A seat-mounted airbag device of a third aspect according to the present invention is the seat-mounted airbag device of the first or second aspect, wherein the base portions of the pair of front and rear chambers connected to the outlet are stored in the headrest in an upwardly convex shape when viewed from the side in the seat width direction.

[0015] According to the third aspect of the invention, the base portions of the pair of front and rear chambers connected to the outlet are stored in a state where they are folded upwardly convex in a side view seen from the seat width direction, so that when the base portions of the pair of front and rear chambers inflate, the vertical center portions on the rear side of the seat can be pushed toward the front and lower side of the seat, and the deployment direction of the pair of front and rear chambers is more effectively stabilized. Effect of the Invention

[0016] As described above, according to the present invention, the deployment behavior of the airbag body positioned in front of the occupant's seat can be stabilized by inflating and deploying through the gap between the occupant's head and the ceiling of the vehicle compartment. [Brief description of the drawings]

[0017] [Figure 1] 1 is a schematic perspective view showing a state in which an airbag of a seat-mounted airbag device according to a first embodiment is inflated and deployed; [Diagram 2]1 is a schematic side view showing a state in which an airbag of a seat-mounted airbag device according to a first embodiment is inflated and deployed. FIG. [Diagram 3] 1 is a schematic plan view showing a state in which an airbag of a seat-mounted airbag device according to a first embodiment is inflated and deployed; [Figure 4] FIG. 2 is a schematic plan view showing the shape of the airbag in the first embodiment before being folded. [Diagram 5] 5(A) is a schematic enlarged cross-sectional view taken along line XX in Fig. 4. (B) is a schematic enlarged cross-sectional view taken along line YY in Fig. 4. [Figure 6] 5(A) to 5(F) are schematic plan views showing a folding process of the airbag in the first embodiment. [Figure 7] FIG. 2 is a schematic plan view showing the shape of the airbag in the first embodiment after being folded. [Figure 8] 1 is a schematic front view, partially in cross section, showing an airbag housed in a headrest in the first embodiment. FIG. [Figure 9] FIG. 2 is a schematic front view showing the shape of a distribution pipe in the first embodiment, partially in cross section, with the airbag omitted. [Figure 10] 1 is a schematic side view, partially in cross section, showing an airbag housed in a headrest in the first embodiment. FIG. [Figure 11] 1 is a schematic plan view, partially in cross section, showing an airbag housed in a headrest in the first embodiment. FIG. [Figure 12] FIG. 2 is a schematic side view showing the airbag in the first embodiment at the initial stage of inflation and deployment. [Figure 13] FIG. 2 is a schematic side view showing the airbag in the middle stage of inflation and deployment in the first embodiment. [Figure 14] FIG. 4 is a schematic side view showing a later stage of inflation and deployment of the airbag in the first embodiment. [Figure 15] 1A is a schematic side view, partially in section, showing a state before gas is supplied to the airbag in the second embodiment, and FIG. 1B is a schematic side view, partially in section, showing a state immediately after gas is supplied to the airbag in the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. For convenience of explanation, the arrow UP shown in each drawing indicates the upward direction of the vehicle and the vehicle seat, the arrow FR indicates the forward direction of the vehicle and the vehicle seat, the arrow RH indicates the rightward direction of the vehicle and the vehicle seat, and the arrow LH indicates the leftward direction of the vehicle and the vehicle seat. Therefore, in the following description, when the directions of up / down, front / rear, and left / right are described without special mention, they indicate up / down, front / rear, and left / right in the vehicle and the vehicle seat. In addition, the left / right direction is synonymous with the vehicle width direction and the seat width direction.

[0019] First Embodiment First, a seat-mounted airbag device (hereinafter simply referred to as "airbag device") 30 according to the first embodiment will be described. As shown in Fig. 1, an 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 (automobile). Here, the vehicle seat 12 refers to a rear seat, not a front seat 13 (see Figs. 12 to 14).

[0020] 1 to 3 also show a crash test dummy (human dummy) as a model of an occupant (seater) to be protected, seated in a vehicle seat 12. The dummy is, for example, a frontal crash test dummy (Hybrid III) AM50 (50th percentile of American adult males). The dummy is seated in a standard seating position defined by the crash test method, and the vehicle seat 12 is located at a standard setting position corresponding to the seating position. Hereinafter, the dummy is referred to as "occupant D."

[0021] The vehicle seat 12 includes a seat cushion 14 on which an occupant D sits (supporting the buttocks and thighs F of the occupant D), and a seat back 16 that is provided to extend upwardly behind the seat cushion 14 in a side view seen from the seat width direction and to be rotatable about the seat width direction as an axial direction, supporting the back of the occupant D. The seat back 16 is integrally provided with a headrest 18 that supports the head H of the occupant D at the center of the upper end portion in the seat width direction. The rear wall of the headrest 18 is formed of a backboard 19 (see FIG. 10).

[0022] 1 to 3, an occupant D seated on a seat cushion 14 of a vehicle seat 12 is restrained to the vehicle seat 12 by a seat belt 22 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 and an anchor, not shown, and a buckle are each provided on the vehicle seat 12.

[0023] The airbag device 30 includes an airbag 32 and a single inflator 44 (see Figs. 9 and 10). The airbag 32 is normally stored in a folded state inside the headrest 18 (see Figs. 8, 10, and 11). The inflator 44 is, for example, a combustion-type or cold gas-type inflator formed into a substantially cylindrical shape, and is provided inside the seatback 16 or straddling from the inside of the seatback 16 to the inside of the headrest 18 along the extending direction of the seatback 16 (with the axial direction facing the up-down direction).

[0024] The airbag device 30 also includes a control device (ECU) (not shown) that controls the operation of the inflator 44. The control device is electrically connected to the inflator 44 and a collision sensor (including a camera, etc.) (not shown), and is configured to detect a frontal collision of the vehicle or predict the inevitability of a frontal collision. The control device activates the inflator 44 when it detects or predicts a frontal collision of the vehicle based on information from the collision sensor.

[0025] That is, when a frontal collision of the vehicle is detected or predicted (hereinafter sometimes referred to as "at the time of a frontal collision of the vehicle"), the inflator 44 is activated by the control device to generate gas and eject it from the ejection port 44A (see Figs. 9 and 10). Note that the type of frontal collision of the vehicle in which the control device activates the inflator 44 includes, in addition to a full-wrap frontal collision, an offset frontal collision such as an oblique collision or a minute-wrap collision.

[0026] The airbag 32 is deployed and inflated forward by being supplied with gas ejected from the inflator 44 from the front of the headrest 18, passing through both the left and right sides of the head H of the occupant D seated in the vehicle seat 12 and above the head H of the occupant D. More specifically, the airbag 32 has a pair of front and rear chambers 34 and an airbag body 40.

[0027] As shown in Figure 4, the pair of front and rear chambers 34 have a pair of left and right front and rear extending portions 34A that, when supplied with gas ejected from the inflator 44, expand and deploy forward through both the left and right sides of the head H of the occupant D and extend in the front-rear direction, a front connecting portion 34B (see Figures 1 to 3) that connects the front ends of the pair of front and rear extending portions 34A in the left-right direction, and a rear connecting portion 34C that connects the rear ends of the pair of front and rear extending portions 34A in the left-right direction.

[0028] The front connecting portion 34B is formed in a generally "T" shaped bag shape in front view, which is continuous with the pair of front-rear extending portions 34A (see Figs. 1 to 3). In addition, a cylindrical root portion 36 extending rearward is integrally formed at the rear end of the pair of front-rear chambers 34 (front-rear extending portions 34A), in other words, at both ends in the seat width direction on the rear surface of the rear connecting portion 34C, and a cylindrical root portion 38 extending rearward is also integrally formed at the center in the seat width direction on the rear surface of the rear connecting portion 34C.

[0029] In the following description, the left root portion 36 may be referred to as the "root portion 36L" and the right root portion 36 may be referred to as the "root portion 36R." The left and right root portions 36 and the central root portion 38 are connected to respective outlets 46A, 48A in respective branch pipes 46, 48 of a distribution pipe (diffuser) 50, which will be described later. The front and rear chambers 34 are formed into a long bag shape (tube shape) by overlapping two long pieces of base fabric and sewing the upper and lower peripheral portions together (see FIG. 5(B)).

[0030] As the pair of front and rear chambers 34 (front and rear extension portions 34A) inflate and deploy, the airbag main body 40 moves forward through between the head H of the occupant D and the ceiling 28 of the vehicle compartment (see Figures 12 to 14), and then, as gas is supplied from the pair of front and rear chambers 34, it inflates and deploys toward the occupant D (rearward) behind the pair of front and rear chambers 34, rearward of the front connecting portion 34B, and is positioned between the pair of front and rear chambers 34 (front and rear extension portions 34A) and in front of the occupant D.

[0031] The airbag body 40 is formed into a bag shape by folding a single piece of base fabric into a predetermined shape and sewing its peripheral portion (see FIG. 5(A)). The periphery of a communication hole (not shown) formed in the rear surface of the center portion in the left-right direction of the base fabric constituting the front connecting portion 34B of the front and rear chambers 34 is connected to the periphery of a communication hole (not shown) formed in the base fabric of the airbag body 40 by sewing the periphery of the communication hole (not shown) formed in the base fabric of the airbag body 40. The base fabric of the front and rear chambers 34 and the base fabric of the airbag body 40 are each made of, for example, a polyamide-based or polyester-based cloth material.

[0032] 4 and 5(A), the airbag body 40 is configured such that the left and right base fabrics 40A on the inner side in the seat width direction are pulled outward in the seat width direction and crushed almost flat before being folded (wound) into a roll. And, as shown in Fig. 4 and 5(B), the pair of front and rear chambers 34 are configured such that the approximate center portions in the up-down direction of the base fabrics 34D are pulled outward in the seat width direction and crushed almost flat before being folded into an accordion shape.

[0033] In this state, the airbag 32 is folded as shown in Fig. 6. That is, first, the airbag body 40 is rolled up from the front side as shown in Fig. 6(A) to Fig. 6(C). In other words, the airbag body 40 is folded up in an outwardly wound roll so that it can be easily unwound by the inertial force accompanying the movement toward the front side.

[0034] Next, as shown in Fig. 6(D) to Fig. 6(F), the pair of front and rear chambers 34 (front and rear extensions 34A) are folded in an accordion shape. Note that the pair of front and rear chambers 34 (front and rear extensions 34A) are folded in an accordion shape with only three peaks. Fig. 6(F) also shows a state in which each branch pipe 46, 48 of a distribution pipe 50, which will be described later, is connected.

[0035] The folded state is shown in Fig. 7, in which the boundary 42 between the airbag body 40 folded in a roll shape and the pair of front and rear chambers 34 folded in an accordion-like shape forms a fold line, and the pair of front and rear chambers 34 are folded downward. Then, the airbag 32 in which the pair of front and rear chambers 34 folded in an accordion-like shape are folded downward relative to the airbag body 40 folded in a roll shape is stored inside the headrest 18 as shown in Fig. 8.

[0036] That is, the airbag 32 is configured to be disposed along the outer shape (upper surface and both left and right side surfaces) of the headrest 18 in a front view. In the airbag 32 in a state before the pair of front and rear chambers 34 are folded downward as shown in Fig. 8, the length from the center line (not shown) in the seat width direction of the airbag body 40 to the outer end portions of the front and rear chambers 34 in the seat width direction is 200 mm to 400 mm, and the position of the boundary portion 42 is about 100 mm to 200 mm from the outer end portions of the front and rear chambers 34 in the seat width direction.

[0037] In addition, a tear line (not shown) is formed on the front surface of the headrest 18. This tear line is configured to rupture under the inflation pressure of the airbag 32 when the airbag 32 is inflated and deployed. This allows the airbag 32 to inflate and deploy from the front surface of the headrest 18 forward, in the order of the pair of front and rear chambers 34 and the airbag body 40.

[0038] 9, a distribution pipe 50 made of resin or metal is disposed on the rear side inside the headrest 18. The distribution pipe 50 branches in three directions, and has cylindrical branch pipes 46 branched to the left and right from the center in the seat width direction, and a cylindrical branch pipe 48 branched upward from the center in the seat width direction. In the following, the branch pipe 46 branched to the left from the center in the seat width direction of the distribution pipe 50 may be referred to as "branch pipe 46L," and the branch pipe 46 branched to the right from the center in the seat width direction of the distribution pipe 50 may be referred to as "branch pipe 46R."

[0039] As shown in FIG. 10, the outlet 46A of the left branch pipe 46L and the outlet 46A of the right branch pipe 46R each extend upward and forward at a predetermined angle (e.g., 20° to 30° with respect to the horizontal) and a predetermined length in a side view, and the outlet 48A of the upper branch pipe 48 also extends upward and forward at a predetermined angle (e.g., 20° to 30° with respect to the horizontal) and a predetermined length in a side view.

[0040] It is preferable that the "predetermined length" of the nozzles 46A and 48A is, for example, 30 mm to 40 mm. If the length of the nozzles 46A and 48A is shorter than 30 mm, the gas may not be ejected in the desired direction, and if it is longer than 40 mm, the thickness of the headrest 18 will be increased unnecessarily.

[0041] 11, the outlet 46A of the left branch pipe 46L and the outlet 46A of the right branch pipe 46R also extend toward the outside and front in the seat width direction at a predetermined angle (for example, 10° to 20° with respect to the front-rear direction) in a plan view. As a result, the pair of front and rear chambers 34 inflate and deploy toward the outside and front in the seat width direction, so that the rolled airbag body 40 moves from the rear side to the front side while being pulled toward the outside in the seat width direction.

[0042] 4 and 6(F), the outlet 46A of the left branch pipe 46L and the outlet 46A of the right branch pipe 46R are connected to the left root portion 36L and the right root portion 36R of the rear connecting portion 34C, respectively, and the outlet 48A of the upper branch pipe 48 is connected to the central root portion 38 of the rear connecting portion 34C. Note that, as shown in FIG. 10, in the airbag 32 accommodated inside the headrest 18, the left and right root portions 36L, 36R (only the left root portion 36L is shown in FIG. 10) are located at approximately the center in the up-down direction on the rear side of the pair of front and rear chambers 34.

[0043] In other words, in a side view, the outlet 46A of the left branch pipe 46L and the outlet 46A of the right branch pipe 46R (only the left branch pipe 46L is shown in Fig. 10) are located approximately in the vertical center on the rear side of the pair of front and rear chambers 34. In addition, as shown in Fig. 9, the inner diameters of the outlet 46A of the left branch pipe 46L and the outlet 46A of the right branch pipe 46R are the same and are formed to be larger (for example, about 1.2 times larger) than the inner diameter of the outlet 48A of the upper branch pipe 48.

[0044] Further, an outlet 44A of the inflator 44 is connected to a cylindrical base 52 extending downward from the center of the distribution pipe 50 in the seat width direction. In other words, the inflator 44 is configured to inject gas into the left branch pipe 46L and the right branch pipe 46R of the distribution pipe 50 capable of supplying gas respectively to the pair of front and rear chambers 34, and is also configured to inject gas into the upper branch pipe 48 of the distribution pipe 50 capable of supplying gas to the center of the rear connecting portion 34C.

[0045] In the airbag device 30 configured as above, as shown in Fig. 1 to Fig. 3, the front-rear extending portions 34A of the pair of inflated and deployed front-rear chambers 34 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 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 front connecting portion 34B. As a result, the front-rear chambers 34 including the pair of front-rear extending portions 34A and the front connecting portion 34B protruding from the headrest 18 are configured to be substantially U-shaped and open rearward in a plan view (see Fig. 3).

[0046] The airbag body 40 moves forward as the pair of front and rear chambers 34 inflate and deploy, and then inflates and deploys rearward (toward the occupant D) as gas is supplied from the front and rear chambers 34. In other words, when the pair of front and rear chambers 34 inflate and deploy, the airbag body 40 passes from the rearward to the frontward through a narrow gap between the head H of the occupant D and the ceiling 28 of the vehicle compartment (see Figures 12 to 14) while remaining folded in a roll.

[0047] The airbag body 40 is inflated and deployed toward the occupant D (rearward) behind the pair of front and rear chambers 34 on the rear side of the front connecting portion 34B, and the inflated and deployed airbag body 40 faces the head H, chest C and abdomen B of the occupant D with gaps in the front-rear direction (see Figs. 1 to 3). The shape of the airbag body 40 when inflated and deployed is set so that it is sandwiched between the thighs F and chest C of the occupant D from the middle to the latter stages of occupant restraint.

[0048] 1 to 3, a pair of left and right rear tethers 54, a pair of left and right front upper tethers 56, and a pair of left and right front lower tethers 58 are attached to the airbag 32. The rear tethers 54, the front upper tethers 56, and the front lower tethers 58 are formed in long strip shapes from, for example, a polyamide-based or polyester-based cloth material. The cloth materials forming the rear tethers 54, the front upper tethers 56, and the front lower tethers 58 are configured to be less stretchable than the base cloth forming the front and rear chambers 34. This resistance to stretching is adjusted by the material and thickness of the cloth.

[0049] The pair of front upper tethers 56 are configured to connect the left and right wall surfaces at the front of the upper part of the airbag body 40, which inflates and deploys above the front and rear chambers 34, to the front parts of the pair of front and rear extending parts 34A. That is, one end of each of the pair of front upper tethers 56 is sewn to the left and right wall surfaces at the front of the upper part of the airbag body 40, which 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 parts of the pair of front and rear extending parts 34A.

[0050] The pair of front lower tethers 58 are configured to connect the left and right wall surfaces on the front side of the lower part of the airbag body 40 that inflates and deploys downward from the front and rear chambers 34 to the front parts of the pair of front and rear extending parts 34A. That is, one end of each of the pair of front lower tethers 58 is sewn to the left and right wall surfaces on the front side 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 parts of the pair of front and rear extending parts 34A.

[0051] Meanwhile, one end of each of the pair of rear tethers 54 is attached by sewing to the underside of the front part of the front and rear chamber 34 (front and rear extending parts 34A) that faces in the seat width direction approximately the center of the inflated and deployed airbag main body 40 in a side view. The other end of each of the pair of rear tethers 54 is attached to the side part of the seat back 16 (or the vehicle body (not shown) rearward of the occupant D). Therefore, when the airbag 32 is inflated and deployed, the pair of rear tethers 54 extend obliquely downward and rearward below the pair of front and rear extending parts 34A.

[0052] That is, the pair of rear tethers 54 adopt an inclined posture inclined diagonally downward and rearward in a side view. As a result, when the occupant D is restrained by the airbag 32, the airbag body 40 is relatively drawn (pulled) diagonally downward and rearward by the pair of rear tethers 54, and the airbag body 40 and the front parts of the pair of front-rear extending parts 34A are relatively drawn diagonally downward and rearward with the headrest 18 as a rotation center in a side view.

[0053] Next, the operation of the airbag device 30 according to the first embodiment configured as above will be described.

[0054] The airbag 32, which has a pair of front and rear chambers 34 and an airbag body 40, is stored in the headrest 18 with the pair of front and rear chambers 34, which are both ends in the seat width direction, folded downward so as to fit the outer shape of the headrest 18 of the vehicle seat 12 in a front view. In other words, the airbag 32 is stored compactly inside the headrest 18.

[0055] In addition, the headrest 18 in which the airbag 32 is stored is formed integrally with the seat back 16. Therefore, compared to a case in which the headrest 18 is separate from the seat back 16, the airbag 32 (airbag device 30) can be prevented from being removed from the vehicle seat 12.

[0056] When a frontal collision of the vehicle is detected (or predicted) by the collision sensor, the inflator 44 is activated under the control of the control device. That is, gas is generated and ejected from the inflator 44. The gas ejected from the inflator 44 is supplied to the pair of front and rear chambers 34 and the rear connecting portion 34C of the airbag 32 through the distribution pipe 50.

[0057] Then, the tear line of the headrest 18 tears open due to the inflation pressure of the pair of front and rear chambers 34 and the inflation pressure through the airbag body 40 at the rear connecting portion 34C, i.e., the pressure applied by the inflated rear connecting portion 34C pressing the airbag body 40 in a rolled-up state toward the front.

[0058] Here, the pair of front and rear chambers 34 housed inside the headrest 18 are folded downward with respect to the airbag body 40 folded in a roll shape in a front view. Each of the outlets 46A in the left and right branch pipes 46 of the distribution pipe 50 that supplies gas ejected from the inflator 44 to the pair of front and rear chambers 34 extends forward and upward at a predetermined angle and a predetermined length in a side view, and is located at approximately the center in the up-down direction on the rear side of the pair of front and rear chambers 34.

[0059] Therefore, when the pair of front and rear chambers 34 begin to expand and deploy as gas begins to eject from each nozzle 46A, the approximately central portion in the vertical direction on the rear side of the pair of front and rear chambers 34 can be effectively pushed forward, stabilizing the deployment direction of the pair of front and rear chambers 34.

[0060] For example, if each of the outlets 46A in the left and right branch pipes 46 of the distribution pipe 50, which supplies gas ejected from the inflator 44 to the pair of front and rear chambers 34, is located at the lower end on the rear side of the pair of front and rear chambers 34 in a side view, the pair of front and rear chambers 34 will be tilted backward when they begin to inflate and deploy, making it difficult to push the pair of front and rear chambers 34 forward.

[0061] In contrast, in this embodiment, since the above-mentioned configuration is adopted, the pair of front and rear chambers 34 does not tilt backward, and the deployment direction of the pair of front and rear chambers 34 is stabilized. As a result, the pair of front and rear chambers 34 inflate and deploy forward from the front of the headrest 18, passing through both the left and right sides of the head H of the occupant D, as shown in Fig. 12.

[0062] This also stabilizes the deployment behavior of the airbag body 40 that moves in association with the inflation and deployment of the pair of front and rear chambers 34. Therefore, the airbag body 40 that is folded in a roll shape can move forward in association with the inflation and deployment of the pair of front and rear chambers 34 above the head H of the occupant D, that is, through the narrow gap between the head H of the occupant D and the ceiling 28 of the vehicle compartment.

[0063] In this manner, when the pair of front and rear chambers 34 inflate and deploy, and the airbag body 40 in a rolled-up state moves forward, as shown in FIG. 13, the head H of the occupant D is inserted relatively into the gap surrounded by the front and rear extending portions 34A of the pair of front and rear chambers 34 and the airbag body 40 in a rolled-up state.

[0064] 14, gas is supplied from the front connecting portion 34B, which connects the front ends of the front and rear extending portions 34A of the pair of front and rear chambers 34 in the left-right direction, through the communication hole, whereby the airbag body 40 is inflated and deployed toward the occupant D. In other words, the airbag body 40 is disposed between the pair of front and rear chambers 34 and in front of the occupant D.

[0065] In this way, after the front and rear chambers 34 have been fully inflated and deployed, gas is supplied to the airbag body 40 from the inflator 44 through the communication holes in the front connecting portion 34B. In other words, the gas that has been ejected from the inflator 44 and flowed through the pair of front and rear extending portions 34A and the front connecting portion 34B of the front and rear chambers 34 is supplied to the airbag body 40 through the communication holes. Therefore, the airbag body 40 can be inflated and deployed with a sufficient delay relative to the pair of front and rear chambers 34.

[0066] This allows the airbag body 40, while still folded in a roll, to reliably and easily pass through the narrow gap between the head H of the occupant D and the ceiling 28 of the vehicle compartment from the rear side to the front side as the pair of front and rear chambers 34 inflate and deploy. This prevents the airbag body 40 from becoming stuck in the narrow gap, and suppresses or prevents poor deployment of the airbag 32.

[0067] In addition, in this embodiment, since the distribution pipe 50 is provided inside the headrest 18, there is no restriction on the mounting position of the inflator 44. Therefore, for example, the inflator 44 can be provided along the extending direction of the seat back 16 (with the axial direction facing the up-down direction) inside the seat back 16 or straddling from the inside of the seat back 16 to the inside of the headrest 18, and it is possible to prevent the seat back 16 and the headrest 18 from becoming larger (increased in thickness).

[0068] Furthermore, when the airbag body 40 is inflated and deployed, the pair of front upper tethers 56 connect both left and right portions at the front side of the upper portion of the airbag body 40 to the front portions of the pair of front and rear extending portions 34A, respectively. The pair of front upper tethers 56 can prevent the airbag body 40 from being accidentally displaced (rotated) upwardly about the front connecting portions 34B relative to the front and rear chambers 34 when the airbag body 40 (airbag 32) is completely inflated and deployed.

[0069] Furthermore, when the airbag body 40 is inflated and deployed, the pair of front lower tethers 58 connect both left and right portions at the front side of the lower part of the airbag body 40 to the front parts of the pair of front and rear extending parts 34A, respectively. The pair of front lower tethers 58 can prevent the airbag body 40 from being inadvertently displaced (rotated) downwardly about the front connecting parts 34B relative to the front and rear chambers 34 when the airbag body 40 (airbag 32) is completely inflated and deployed.

[0070] Furthermore, when the airbag 32 is fully inflated and deployed, the pair of rear tethers 54 extend obliquely downward and rearward below the pair of front-rear extending portions 34A. That is, the pair of rear tethers 54 restrict the movement of the airbag body 40 obliquely upward and forward. This makes it possible to suppress the swinging of the airbag 32 in the up-down and front-rear directions (contributing to stabilizing the deployment behavior of the airbag body 40).

[0071] In this state, the occupant D, who has moved forward due to inertia caused by the impact of a frontal collision of the vehicle, is restrained by the airbag body 40. Specifically, when the occupant D is restrained, the front and rear chambers 34 (front and rear extensions 34A) are expanded forward by the forward movement of the occupant D. Then, the airbag body 40 is pressed forward by the occupant D, and is compressed and deformed forward.

[0072] Therefore, the energy absorption performance of the airbag body 40 can be improved, and the occupant restraint performance can be effectively ensured. In other words, when both the front and rear chambers 34 and the airbag body 40 are subjected to a tensile load, the load applied from the airbag body 40 to the occupant D increases, but the load applied to the occupant D can be reduced by the compressive deformation of the airbag body 40.

[0073] Moreover, the airbag body 40 is shaped so as to be sandwiched between the thighs F and chest C of the occupant D from the middle to later stages of restraining the occupant by the airbag 32, and can come into contact with a wide area of ​​the upper body of the occupant D. This makes it possible to effectively reduce the load applied from the airbag body 40 to the occupant D.

[0074] In addition, since the airbag body 40 inflates and deploys toward the occupant D on the rear side of the front connecting portion 34B after the front and rear chambers 34 are inflated and deployed, the gap between the airbag body 40 and the occupant D becomes smaller. As a result, the occupant D is restrained by the airbag body 40 early, and the initial restraint performance of the airbag body 40 for the occupant D can be improved.

[0075] In addition, since the pair of rear tethers 54 are less likely to stretch than the front and rear chambers 34, when the occupant D is restrained, the airbag body 40 is relatively pulled diagonally downward and rearward by the pair of rear tethers 54. This makes it possible to stabilize the vertical position of the airbag body 40 with respect to the head H of the occupant D when the occupant is restrained. In other words, according to this airbag 32, the occupant D can be appropriately restrained.

[0076] <Second embodiment> Next, an airbag device 30 according to a second embodiment will be described. Note that the same reference numerals are used for the same parts as those in the first embodiment, and detailed descriptions (including common functions) will be omitted as appropriate.

[0077] As shown in FIG. 15(A), the airbag device 30 according to the second embodiment differs from the first embodiment only in that the left and right root portions 36L, 36R (only the left root portion 36L is shown in FIG. 15) of the pair of front and rear chambers 34 connected to each outlet 46A in the left and right branch pipes 46L, 46R (only the left branch pipe 46L is shown in FIG. 15) of the distribution pipe 50 are stored in the headrest 18 in a folded upward convex shape (approximately an arc shape convex upward) in a side view.

[0078] In this manner, when the left and right root portions 36L, 36R of the pair of front and rear chambers 34, which are respectively connected to each of the nozzles 46A in the left and right branch pipes 46L, 46R of the distribution pipe 50, are stored in a folded upward convex shape in side view, as shown in Figure 15 (B), gas is supplied from each of the nozzles 46A, causing the left and right root portions 36L, 36R to expand and deploy, so that the upper portions on the rear sides of the pair of front and rear chambers 34 can be pressed forward and downward by the expanded left and right root portions 36L, 36R.

[0079] Then, gas is supplied (sprayed) from the upper rear side to the lower front side in a side view to the approximately vertical center on the rear side of the pair of front and rear chambers 34 by the inflated left and right root portions 36L, 36R, so that the pair of front and rear chambers 34 can be pushed forward and downward more effectively. Therefore, the deployment direction of the pair of front and rear chambers 34 can be stabilized more effectively.

[0080] The seat-mounted airbag device 30 according to this embodiment has been described above with reference to the drawings. However, the seat-mounted airbag device 30 according to this embodiment is not limited to the one shown in the drawings, and the design can be appropriately modified within the scope of the gist of the present invention.

[0081] For example, the distribution pipe 50 may be provided straddling between the inside of the headrest 18 and the inside of the seat back 16. In addition, while the illustrated root parts 36, 38 are attached by being inserted into the inside of the respective ejection ports 46A, 48A, this is not limiting, and the distribution pipe 50 may be configured to be attached by being placed over the outside of the respective ejection ports 46A, 48A.

[0082] Although not shown, the distribution pipe 50 may not be provided inside the headrest 18, and each of the outlets 44A of the three inflators 44 may be directly connected to each of the base portions 36L, 36R, 38. In this case, since each inflator 44 protrudes obliquely rearward and downward, the thickness of the headrest 18 increases, but the same effect as above can be obtained even if each of the outlets 44A of the two inflators 44 directly connected to the left and right base portions 36L, 36R is positioned approximately in the center in the up-down direction on the rear side of each of the pair of front and rear chambers 34. [Explanation of symbols]

[0083] 12 Vehicle seats 18 Headrest 28 Ceiling 30 Airbag device 32 Airbag 34 Front and rear chambers 36 Base 40 Airbag body 44 Inflator 46A spout 50 minutes plumbing D. Crew H head

Claims

1. An inflator that is provided in a vehicle seat and ejects gas when the vehicle crashes; an airbag having a pair of front and rear chambers which are inflated and deployed toward the front of the seat by passing through both the left and right sides of the head of an occupant seated in the vehicle seat when gas ejected from the inflator is supplied to the pair of front and rear chambers, and an airbag body which moves toward the front of the seat by passing between the head of the occupant and a ceiling of a vehicle compartment as the pair of front and rear chambers inflate and deploy, and which is inflated and deployed toward the rear of the seat between the pair of front and rear chambers when the gas is supplied from the pair of front and rear chambers and which is disposed in front of the seat of the occupant; Equipped with The airbag comprises: When viewed from the front side of the seat, the pair of front and rear chambers are folded toward a seat lower side with respect to the airbag body and are stored in a headrest of the vehicle seat, a gas outlet for ejecting gas from the inflator being located at a vertical center of the pair of front and rear chambers on the seat rear side in a side view seen from the seat width direction;

2. a distribution pipe provided in the vehicle seat and capable of supplying gas ejected from the inflator to each of the pair of front and rear chambers; the distribution pipe has a jet port connected to a base portion of each of the pair of front and rear chambers, 2. The seat-mounted airbag device according to claim 1, wherein the outlet extends a predetermined length toward the front and upper side of the seat when viewed from the side in the seat width direction, and is located in a vertical center portion of the pair of front and rear chambers on the seat rear side.

3. 3. The seat-mounted airbag device according to claim 1, wherein base portions of the pair of front and rear chambers connected to the outlet are stored in the headrest in a folded upward convex shape when viewed from the side in the seat width direction.

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