Seat-mounted airbag device and method for folding airbag

Abstract

To provide a seat-mounted airbag device capable of achieving both improvement of deployment performance and early completion of inflation and deployment 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 front side of the occupant; and to provide a method for folding an airbag of the same.SOLUTION: A seat-mounted airbag device 30 comprises an airbag 32 comprising: a pair of 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 H of an occupant D; and an airbag body 40 which, in association with inflation and deployment of the pair of front-rear chambers 34, moves forward through between the head H of the occupant D and a ceiling, and which, when the gas is supplied from the pair of front-rear chambers 34, is inflated and deployed rearward between the pair of front-rear chambers 34, and is disposed at a front side of the occupant D. The airbag 32 comprises, at a rear side of the airbag body 40, a pushing structure 34C for pushing the airbag body 40 forward.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present invention relates to a seat-mounted airbag device and a method for folding an airbag. [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 body is inflated and deployed while passing through the gap between the head of the occupant and the ceiling from the seat back, and is positioned in front of the occupant. Therefore, it is desired that the airbag body does not allow gas to flow into it and remains small until it passes over the head of the occupant, and then gas is allowed to flow in and inflate it after it has passed over the head of the occupant.

[0006] However, when gas is introduced to inflate the airbag body after the airbag has passed over the head of the occupant, it tends to take a long time for the airbag body to fully inflate and deploy. Thus, there is still room for improvement in terms of both improving the deployment performance of the airbag body in the gap between the occupant's head and the ceiling and speeding up the completion of inflation and deployment of the airbag body.

[0007] Therefore, an object of the present invention is to provide a seat-mounted airbag device and a method for folding the airbag, which can achieve both improved deployment performance 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, and quicker completion of inflation and deployment. [Means for solving the problem]

[0008] In order to achieve the above object, a seat-mounted airbag device of a first aspect of the present invention comprises an airbag that is provided on a vehicle seat and ejects gas upon a vehicle collision, a pair of front and rear chambers that are supplied with gas ejected from the inflator and that inflate and deploy 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, and an airbag body that moves toward the front of the seat by passing between the occupant's head and the ceiling of the vehicle compartment 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 from the pair of front and rear chambers, and is positioned on the front side of the seat of the occupant, and the airbag has an extrusion structure on the seat rear side of the airbag body that pushes the airbag body toward the front of the seat.

[0009] 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 compartment 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 seat of the occupant. In other words, the airbag body inflates and deploys with a delay relative to the pair of front and rear chambers, so that it can reliably move between the head of the occupant and the ceiling of the vehicle compartment.

[0010] In addition, this airbag has a push-out structure on the seat rear side of the airbag body that pushes the airbag body toward the front of the seat. Therefore, the airbag body is forcibly pushed toward the front of the seat from the initial position (mounted position) by the push-out structure. Therefore, in the event of a vehicle collision, the time that the airbag body remains in the initial position is shortened, and the airbag body can be quickly inflated and deployed.

[0011] In other words, according to the present invention, the airbag body disposed in front of the seat of the occupant is inflated and deployed through the gap between the occupant's head and the ceiling of the vehicle compartment, thereby improving the deployment performance of the airbag body and speeding up the completion of inflation and deployment. Note that "at the time of a collision" as used herein also includes a time when the inevitability of a collision is predicted (foreseen).

[0012] A seat-mounted airbag device according to a second aspect of the present invention is the seat-mounted airbag device according to the first aspect, wherein the push-out structure is constituted by a push-out chamber that connects the pair of front and rear chambers to each other.

[0013] According to the second aspect of the invention, the pushing-out structure is constituted by a pushing-out chamber that connects the pair of front and rear chambers to each other, and therefore the airbag body is reliably pushed out from the initial position (mounted position) toward the front side of the seat by the pushing-out chamber.

[0014] A seat-mounted airbag device according to a third aspect of the present invention is the seat-mounted airbag device according to the first aspect, wherein the push-out structure is configured with a push-out chamber separate from the pair of front and rear chambers.

[0015] According to the third aspect of the invention, the pushing structure is configured with a push-out chamber separate from the pair of front and rear chambers. Therefore, the airbag body is reliably pushed from the initial position (mounted position) toward the front side of the seat by the push-out chamber. In addition, since the push-out chamber is configured as a separate body from the pair of front and rear chambers, the structure of the airbag is simplified.

[0016] A seat-mounted airbag device of a fourth aspect according to the present invention is the seat-mounted airbag device of the first aspect, wherein the extrusion structure is composed of an extrusion fabric that connects the pair of front and rear chambers to each other.

[0017] According to the fourth aspect of the invention, the extrusion structure is formed of an extrusion cloth that connects the pair of front and rear chambers to each other. Therefore, when the pair of front and rear chambers move toward the front side of the seat, tension is applied to the extrusion cloth in the seat width direction. Therefore, the airbag body is reliably pushed from the initial position (mounted position) toward the front side of the seat by the extrusion cloth. In addition, since the extrusion structure is formed of an extrusion cloth, the airbag can be stored compactly and is lightweight.

[0018] A seat-mounted airbag device of a fifth aspect of the present invention is the seat-mounted airbag device of the second or third aspect, wherein a single inflator is provided, and the vehicle seat is provided with a distribution pipe capable of supplying gas ejected from the inflator to the pair of front and rear chambers and the extrusion chamber, respectively, and the inner diameter of the outlet of the distribution pipe connected to the root portion of the pair of front and rear chambers is larger than the inner diameter of the outlet of the distribution pipe connected to the root portion of the extrusion chamber.

[0019] According to the fifth aspect of the invention, a single inflator is provided, and gas ejected from the inflator is supplied to the pair of front and rear chambers and the extrusion chamber by distribution pipes. Therefore, compared to a case where one or two inflators are provided for the pair of front and rear chambers and one is provided for the extrusion chamber, the number of parts and mounting space are reduced, and manufacturing costs are reduced.

[0020] In addition, the inner diameter of the outlet of the distribution pipe connected to the base of the pair of front and rear chambers is made larger than the inner diameter of the outlet of the distribution pipe connected to the base of the extrusion chamber, so that the amount of gas supplied to the pair of front and rear chambers is greater than the amount of gas supplied to the extrusion chamber, and the airbag body can be inflated and deployed more quickly.

[0021] A seat-mounted airbag device of a sixth aspect of the present invention is the seat-mounted airbag device of the fifth aspect, wherein a headrest of the vehicle seat is integrally formed with a seat back of the vehicle seat, and the inflator is disposed along the extending direction of the seat back.

[0022] According to the sixth aspect of the invention, the headrest is integrally formed with the seat back. Therefore, the airbag is prevented from being removed from the vehicle seat, compared to when the headrest is separate from the seat back. Also, the inflator is arranged along the extending direction of the seat back. Therefore, the headrest and the seat back are prevented from becoming larger (thicker) than when the inflator is arranged along a direction intersecting the extending direction of the seat back.

[0023] A seat-mounted airbag device of a seventh aspect of the present invention is the seat-mounted airbag device of the second or third aspect, wherein the two inflators are a first inflator that supplies gas to the pair of front and rear chambers and a second inflator that supplies gas to the extrusion chamber, and the vehicle seat is provided with a first distribution pipe that can supply gas ejected from the first inflator to the pair of front and rear chambers and a second distribution pipe that can supply gas ejected from the second inflator to the extrusion chamber, and the inner diameter of the outlet of the first distribution pipe connected to the base portion of the pair of front and rear chambers is larger than the inner diameter of the outlet of the second distribution pipe connected to the base portion of the extrusion chamber.

[0024] According to the seventh aspect of the invention, two inflators are provided, a first inflator that supplies gas to the pair of front and rear chambers, and a second inflator that supplies gas to the extrusion chamber, and the gas ejected from the first inflator is supplied to the pair of front and rear chambers by the first distribution pipe, and the gas ejected from the second inflator is supplied to the extrusion chamber by the second distribution pipe. Therefore, compared to the case where two inflators are provided for the pair of front and rear chambers and one inflator is provided for the extrusion chamber, the number of parts and the mounting space are reduced, and the manufacturing cost is reduced.

[0025] In addition, the inner diameter of the outlet of the first distribution pipe connected to the base of the pair of front and rear chambers is made larger than the inner diameter of the outlet of the second distribution pipe connected to the base of the extrusion chamber. Therefore, the amount of gas supplied to the pair of front and rear chambers is greater than the amount of gas supplied to the extrusion chamber, and the airbag body can be inflated and deployed more quickly.

[0026] Furthermore, a seat-mounted airbag device of an eighth aspect of the present invention is the seat-mounted airbag device of the seventh aspect, wherein a headrest of the vehicle seat is integrally formed with a seat back of the vehicle seat, and the first inflator and the second inflator are arranged along the extending direction of the seat back.

[0027] According to the eighth aspect of the invention, the headrest is integrally formed with the seat back. Therefore, the airbag is prevented from being removed from the vehicle seat, compared to when the headrest is separate from the seat back. Also, the first inflator and the second inflator are arranged along the extending direction of the seat back. Therefore, the headrest and the seat back are prevented from becoming larger (thicker) than when the first inflator and the second inflator are arranged along a direction intersecting the extending direction of the seat back.

[0028] A seat-mounted airbag device of a ninth aspect according to the present invention is the seat-mounted airbag device of the second or third aspect, wherein three inflators are provided so as to be capable of supplying gas to the pair of front and rear chambers and the extrusion chamber, respectively, and the output of the two inflators supplying gas to the pair of front and rear chambers, respectively, is higher than the output of the single inflator supplying gas to the extrusion chamber.

[0029] According to the ninth aspect of the invention, three inflators are provided so as to be capable of supplying gas to the pair of front and rear chambers and the extrusion chamber, respectively, and the output of the two inflators supplying gas to the pair of front and rear chambers, respectively, is set to be higher than the output of the one inflator supplying gas to the extrusion chamber. Therefore, the amount of gas supplied to the pair of front and rear chambers is greater than the amount of gas supplied to the extrusion chamber, and the airbag body can be inflated and deployed more quickly.

[0030] A seat-mounted airbag device of a tenth aspect of the present invention is a seat-mounted airbag device of any one of the first to ninth aspects, wherein a valve mechanism is provided at the tip of the pair of front and rear chambers to instantaneously block the inflow of gas.

[0031] According to the tenth aspect of the invention, a valve mechanism that instantly blocks the inflow of gas is provided at the tip of the pair of front and rear chambers. This makes it possible to control the gas flow so that it does not flow into the airbag body until it passes between the occupant's head and the ceiling of the vehicle compartment and moves to the front side of the seat. Therefore, the airbag body can reliably move to the front side of the seat, and as a result, the airbag body can be inflated and deployed more quickly.

[0032] In addition, an eleventh aspect of the airbag folding method according to the present invention is a method for folding an airbag having a pair of front and rear chambers that are supplied with gas ejected from an inflator provided in a vehicle seat in the event of a vehicle collision, and that inflate and deploy 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, and an airbag body that moves toward the front of the seat through between the occupant's head and the ceiling of the vehicle compartment 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 as the gas is supplied from the pair of front and rear chambers, the method including a deployment step of flattening the airbag, and a pulling out step of pulling out a base fabric on an outer side of the airbag body in the seat width direction outward in the seat width direction.

[0033] According to the eleventh aspect of the invention, when the airbag is folded, the deployment process flattens the airbag, and the pull-out process pulls out the base fabric of the airbag body on the outer side in the seat width direction to the outer side in the seat width direction. This reduces the thickness of the airbag body due to the overlapping base fabric, and therefore improves the deployment performance of the airbag body that moves to the front side of the seat through the gap between the occupant's head and the ceiling of the vehicle compartment. In other words, the airbag body can reliably move to the front side of the seat, which results in an earlier completion of inflation and deployment of the airbag body.

[0034] An airbag folding method according to a twelfth aspect of the present invention is the airbag folding method according to the eleventh aspect, and includes a roll folding process of roll-folding the tip portions of the pair of front and rear chambers from the front side of the seat toward the upper side of the seat a predetermined number of times, and a bellows folding process of accordion-folding the pair of front and rear chambers excluding the tip portions a plurality of times.

[0035] According to the twelfth aspect of the invention, the tip portions of the pair of front and rear chambers are roll-folded from the front side of the sheet toward the upper side of the sheet a predetermined number of times in the roll folding process, and the pair of front and rear chambers excluding the tip portions are accordion-folded multiple times in the bellows folding process.

[0036] Here, it is known that accordion folding deploys faster than roll folding. Therefore, the pair of front and rear chambers are inflated and deployed early, except for their tip portions. In addition, the tip portions of the pair of front and rear chambers are controlled not to inflate and deploy until the airbag body passes between the occupant's head and the ceiling of the vehicle compartment and moves toward the front side of the seat. This allows the airbag body to reliably move toward the front side of the seat, which ultimately leads to an earlier completion of inflation and deployment of the airbag body.

[0037] An airbag folding method according to a thirteenth aspect of the present invention is the airbag folding method according to the twelfth aspect, wherein the roll folding step involves one roll folding.

[0038] According to the thirteenth aspect of the invention, in the rolling step, the tip portions of the pair of front and rear chambers are rolled once. If the number of rolls is, for example, 0.5, gas starts to flow into the airbag body before the airbag body moves to the front side of the seat through the gap between the occupant's head and the ceiling of the vehicle compartment. This makes it difficult for the airbag body to move to the front side of the seat through the gap between the occupant's head and the ceiling of the vehicle compartment. On the other hand, if the number of rolls is, for example, 1.5, the flow of gas from the tip portions of the pair of front and rear chambers into the airbag body after the airbag body moves to the front side of the seat is delayed, so that the airbag body is inflated and deployed to the rear side of the seat slowly.

[0039] In contrast, because the airbag body is folded once, gas does not begin to flow into the airbag body before the airbag body passes between the occupant's head and the ceiling of the vehicle compartment and moves toward the front side of the seat, making it easier for the airbag body to move toward the front side of the seat through the gap between the occupant's head and the ceiling of the vehicle compartment. In addition, after the airbag body moves toward the front side of the seat, gas flows into the airbag body from the tips of the pair of front and rear chambers more quickly, so the airbag body inflates and deploys toward the rear side of the seat more quickly. This allows the airbag body to complete inflation and deployment more quickly.

[0040] Further, the airbag folding method of a fourteenth aspect according to the present invention is the airbag folding method of the twelfth or thirteenth aspect, wherein the bellows folding step involves folding the airbag in an accordion manner three times.

[0041] According to the fourteenth aspect of the invention, in the bellows folding step, the pair of front and rear chambers are folded 3 times in bellows fashion. Therefore, the pair of front and rear chambers, except for their tip portions, are inflated and deployed earlier than when the number of bellows folding steps is four or more. Effect of the Invention

[0042] As described above, according to the present invention, it is possible to achieve both improved deployment performance of the airbag body located in front of the occupant's seat and earlier completion of inflation and deployment by inflating and deploying through the gap between the occupant's head and the ceiling of the vehicle compartment. [Brief description of the drawings]

[0043] [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] 1A is a schematic front view showing the shape of a distribution pipe in the first embodiment with an airbag omitted in a partial cross-section, and FIG. 1B is a schematic side view showing the airbag stored in the headrest in the first embodiment with a partial cross-section. [Figure 10] 3A to 3C are schematic plan views showing the initial stage of inflation and deployment of the airbag in the first embodiment. [Figure 11] FIG. 2 is a schematic side view showing the airbag in the first embodiment at the initial stage of inflation and deployment. [Figure 12]FIG. 2 is a schematic side view showing the airbag in the middle stage of inflation and deployment in the first embodiment. [Figure 13] FIG. 4 is a schematic side view showing a later stage of inflation and deployment of the airbag in the first embodiment. [Figure 14] 10(A) to 10(C) are schematic plan views showing the initial stage of inflation and deployment of an airbag in a second embodiment. [Figure 15] 13A is a schematic front view showing the shape of a distribution pipe in a third embodiment with an airbag omitted in a partial cross-section, and FIG.13B is a schematic side view showing the airbag stored in a headrest in the third embodiment with a partial cross-section. [Figure 16] 13(A) to 13(C) are schematic plan views showing the initial stage of inflation and deployment of an airbag in a fourth embodiment. [Figure 17] 13(A) to 13(C) are schematic plan views showing the initial stage of inflation and deployment of an airbag in a fifth embodiment. [Figure 18] FIG. 13 is a schematic perspective view showing a valve mechanism in a sixth embodiment. [Figure 19] 19(A) to 19(C) are schematic cross-sectional views taken along line ZZ in FIG. 18, illustrating the operation of the valve mechanism in the sixth embodiment. [Figure 20] FIG. 13 is a schematic side view showing a valve mechanism in the seventh embodiment. [Figure 21] 13(A) and 13(B) are schematic cross-sectional views showing the operation of a valve mechanism in a seventh embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0044] 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.

[0045] 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. 11 to 13).

[0046] 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."

[0047] 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. 9(B)).

[0048] 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.

[0049] The airbag device 30 includes an airbag 32 and a single inflator 44 (see FIG. 9). The airbag 32 is normally stored in a folded state inside the headrest 18 (see FIGS. 8, 9(B), and 10(A)). 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).

[0050] 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.

[0051] 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 FIG. 9). 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.

[0052] 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.

[0053] 4, the pair of front and rear chambers 34 includes a pair of left and right front and rear extending portions 34A that are inflated and deployed forward through both the left and right sides of the head H of the occupant D by being supplied with gas ejected from the inflator 44, a front connecting portion 34B (see FIGS. 1 to 3) that connects the front ends of the pair of front and rear extending portions 34A in the left and right direction, and a rear connecting portion 34C that connects (connects each other to) the rear ends of the pair of front and rear extending portions 34A in the left and right direction. Note that this rear connecting portion 34C is the "extrusion chamber" and is disposed on the rear side of the airbag body 40.

[0054] 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.

[0055] 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)).

[0056] 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 11 to 13), 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.

[0057] 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.

[0058] Here, a method of folding the airbag 32 will be described. As shown in Fig. 4 and Fig. 5(A), the airbag 32 is first deployed in a flat shape (deployment process). Next, before the airbag body 40 is folded (wound) into a roll, the base fabrics 40A on both the left and right sides that are inserted on the inner side in the seat width direction are pulled outward in the seat width direction and crushed almost flat (pulling process). Then, as shown in Fig. 4 and Fig. 5(B), before the pair of front and rear chambers 34 are folded in an accordion shape, the approximately central parts in the up-down direction of the base fabrics 34D are pulled outward in the seat width direction and crushed almost flat (pulling process).

[0059] In this state, the airbag 32 is folded as shown in Fig. 6. First, as shown in Figs. 6(A) to 6(C), the airbag body 40 is rolled up from the front side to the upper side. 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 to the front side. Then, the tip portions 34F of the pair of front and rear chambers 34 (front and rear extending portions 34A) are rolled up once from the front side to the upper side (outwardly rolled: roll folding process).

[0060] 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 (accordion folding process) except for the rolled tip portion 34F. The pair of front and rear chambers 34 (front and rear extensions 34A) excluding the tip portion 34F are folded in an accordion shape with only three peaks. In other words, the accordion folding is performed three times. 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.

[0061] The folded state is shown in Figure 7, where the boundary 42 (see Figures 7 and 8) between the airbag body 40 folded into a roll and the rolled-up tip portions 34F of the pair of front and rear chambers 34 forms a fold line, allowing the pair of front and rear chambers 34 to be folded downward.

[0062] 8, the airbag 32 in this state is stored inside the headrest 18. In other words, the airbag 32 is configured to be arranged along the outer shape (upper surface and both left and right side surfaces) of the headrest 18 when viewed from the front, and the position where the airbag 32 is stored in this state is the initial position (mounted position) of the airbag 32.

[0063] 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.

[0064] 9(A), 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."

[0065] As shown in Figure 9(B), 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° from 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° from the horizontal) and a predetermined length in a side view.

[0066] 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.

[0067] 10, 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.

[0068] 4, 6(F), and 10, 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. 9(B), 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. 9(B)) are located at approximately the center in the up-down direction on the rear side of the pair of front and rear chambers 34.

[0069] 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. 9(B)) 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(A), 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.

[0070] 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.

[0071] 10(B) and 10(C), the airbag body 40 folded in a roll shape is pushed forward by the inflated rear connecting portion 34C to move. In other words, the airbag body 40 is not only moved forward from the initial position by the inflation and deployment of the pair of front and rear chambers 34, but is also forcibly pushed forward by the inflated rear connecting portion 34C. In this way, the rear connecting portion 34C is a push-out chamber that assists in pushing the airbag body 40 forward, and constitutes a push-out structure.

[0072] 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).

[0073] 11 to 13, 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. That is, when the pair of front and rear chambers 34 inflate and deploy, the airbag body 40 passes through the narrow gap between the head H of the occupant D and the ceiling 28 of the vehicle compartment from the rearward to the frontward while remaining folded in a roll (as shown by the imaginary line and arrow A in FIG. 11).

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] Next, the operation of the airbag device 30 and the method for folding the airbag 32 according to the first embodiment configured as above will be described.

[0081] 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, and this stored position is the initial position of the airbag 32.

[0082] 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.

[0083] 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.

[0084] Here, the inflator 44 is disposed singly along the extending direction of the seat back 16 of the vehicle seat 12, and ejects gas into a distribution pipe 50 capable of supplying gas to the pair of front and rear chambers 34 (left and right root portions 36L, 36R) and the rear connecting portion 34C (center root portion 38). In other words, gas ejected from the single inflator 44 disposed along the extending direction of the seat back 16 is supplied by the distribution pipe 50 to the pair of front and rear chambers 34 and the rear connecting portion 34C.

[0085] Therefore, compared to when the nozzle 44A of the inflator 44 is directly connected to each of the pair of front and rear chambers 34 (left and right root portions 36L, 36R) and the rear connecting portion 34C (central root portion 38), i.e., when three inflators 44 are arranged along a direction intersecting the extension direction of the seat back 16 in a side view (protruding diagonally downward and rearward), it is possible to prevent the headrest 18 and seat back 16 from becoming larger (increased in thickness), and it is possible to reduce the number of parts and mounting space, thereby reducing manufacturing costs.

[0086] In this manner, when gas is supplied to the pair of front and rear chambers 34, the tear lines of the headrest 18 are ruptured by the inflation pressure of the pair of front and rear chambers 34, and as shown in FIG. 11, 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.

[0087] At this time, the respective outlets 46A of the left and right branch pipes 46L, 46R connected to the left and right root portions 36L, 36R of the pair of front and rear chambers 34 extend outwardly and forwardly in the seat width direction at a predetermined angle and a predetermined length in a plan view. Therefore, the pair of front and rear chambers 34 inflate and deploy as intended outwardly and forwardly in the seat width direction.

[0088] As a result, even if the pair of front and rear chambers 34 of the airbag 32 are folded downward relative to the airbag body 40 and stored in the headrest 18, the folded state is released when the airbag 32 is inflated and deployed. Therefore, even if the position of the head H of the occupant D varies in the left-right direction, the inflation and deployment performance of the pair of front and rear chambers 34 of the airbag 32 can be ensured.

[0089] As described above, when gas is supplied to the pair of front and rear chambers 34, gas is also supplied to the rear connecting part 34C. That is, the rear connecting part 34C inflates forward. Then, the tear line of the headrest 18 is torn open by the inflation pressure via the airbag body 40 of the rear connecting part 34C, that is, the pressing force of the inflated rear connecting part 34C pressing the rolled-up airbag body 40 forward.

[0090] Then, the airbag body 40 pushed forward by the inflated rear connecting portion 34C moves forward along with the inflation and deployment of the pair of front and rear chambers 34, passing above the head H of the occupant D (see FIG. 11). At this time, since the pair of front and rear chambers 34 inflate and deploy toward the outside and front in the seat width direction, the airbag body 40 moves forward while being pulled outward in the seat width direction.

[0091] In this manner, the airbag body 40 in the rolled-up state is forcibly pushed forward from the initial position by the rear connecting portion 34C which is the push-out chamber, and is pulled outward in the seat width direction by the pair of front and rear chambers 34, while moving forward with the inflation and deployment of the pair of front and rear chambers 34. Therefore, in the event of a frontal collision of the vehicle, the time during which the airbag body 40 in the rolled-up state remains in the initial position is shortened.

[0092] Furthermore, when the airbag 32 is folded, it is flattened in the deployment process, and the base fabric 40A of the airbag body 40 on the outer side in the seat width direction is pulled outward in the seat width direction in the pull-out process. Therefore, in the airbag 32, the thickness due to the overlapping of the base fabrics can be reduced, and the thickness of the airbag body 40 can be reduced. Therefore, when the airbag body 40 moves forward through a narrow gap between the head H of the occupant D and the ceiling 28 of the vehicle compartment, the occurrence of a problem of the airbag body 40 getting stuck in the narrow gap can be prevented, and the occurrence of poor deployment of the airbag 32 can be suppressed or prevented.

[0093] 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. 12, 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.

[0094] 13, 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.

[0095] As described above, gas is supplied to the airbag body 40 from the inflator 44 through the communication hole of the front connecting portion 34B after the pair of front and rear chambers 34 have been fully inflated and deployed. That is, 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 is supplied to the airbag body 40 through the communication hole, so that the airbag body 40 inflates and deploys with a delay relative to the pair of front and rear chambers 34.

[0096] In addition, the substantially vertical center portions of the base fabrics 34D of the pair of front and rear chambers 34 are pulled outward in the sheet width direction and crushed in the pulling process, and the tip portions 34F of the pair of front and rear chambers 34 are roll-folded once from the front side toward the upper side in the roll-folding process. Then, the pair of front and rear chambers 34 excluding the tip portions 34F are accordion-folded three times in the accordion-folding process.

[0097] Here, it is known that bellows folding develops faster than roll folding. Therefore, when the pair of front and rear chambers 34 is folded bellows three times, the pair of front and rear chambers 34, except for the tip portions 34F, are inflated and deployed earlier than when the pair of front and rear chambers 34 is folded bellows four or more times. The tip portions 34F of the pair of front and rear chambers 34 that are folded into a roll only once can control the airbag body 40 not to inflate and deploy until it passes between the head H of the occupant D and the ceiling 28 of the vehicle cabin and moves forward.

[0098] Specifically, when the number of roll folds at the tip portions 34F of the pair of front and rear chambers 34 is, for example, 0.5, gas starts to flow into the airbag body 40 before the airbag body 40 moves forward between the head H of the occupant D and the ceiling 28 of the vehicle compartment. This makes it difficult for the airbag body 40 to move forward between the head H of the occupant D and the ceiling 28 of the vehicle compartment. When the number of roll folds is, for example, 1.5, the flow of gas into the airbag body 40 from the tip portions 34F of the pair of front and rear chambers 34 becomes slower after the airbag body 40 moves forward, so that the inflation and deployment of the airbag body 40 toward the rear side becomes slower.

[0099] In contrast, in the first embodiment, the number of roll folds is one, so that gas does not start to flow into the airbag body 40 before the airbag body 40 moves forward through between the head H of the occupant D and the ceiling 28 of the vehicle compartment, and the airbag body 40 can easily move forward through between the head H of the occupant D and the ceiling 28 of the vehicle compartment. In addition, after the airbag body 40 moves forward, gas flows into the airbag body 40 from the tip ends 34F of the pair of front and rear chambers 34 more quickly, so that the airbag body 40 inflates and deploys rearward more quickly.

[0100] That is, according to the first embodiment, the airbag body 40 can be made to pass (move) reliably and quickly from the rear side to the front side through the narrow gap between the head H of the occupant D and the ceiling 28 of the vehicle compartment as the pair of front and rear chambers 34 inflate and deploy, while remaining in a rolled-up state, and can be quickly inflated and deployed toward the occupant D after passing through, thereby improving the deployment performance. Therefore, it is possible to speed up the completion of inflation and deployment of the airbag body 40 that is mounted in an initial position in a rolled-up state.

[0101] Moreover, in this first embodiment, the inner diameter of each of the outlets 46A of the left and right branch pipes 46L, 46R connected to the respective root portions 36L, 36R of the pair of front and rear chambers 34 is made larger than the inner diameter of the outlet 48A of the branch pipe 48 connected to the root portion 38 of the rear connecting portion 34C. Therefore, the amount of gas supplied to the pair of front and rear chambers 34 can be made larger than the amount of gas supplied to the rear connecting portion 34C, which also makes it possible to hasten the completion of inflation and deployment of the airbag body 40.

[0102] Thus, according to the first embodiment, it is possible to improve the deployment performance of the airbag body 40 disposed in front of the occupant D and complete inflation and deployment earlier by inflating and deploying through the gap between the head H of the occupant D and the ceiling 28 of the vehicle compartment. In particular, since the pushing-out structure that assists in pushing out the airbag body 40 is constituted by the rear connecting portion 34C as a pushing-out chamber that connects the pair of front and rear chambers 34 to each other, the airbag body 40 that is folded into a roll can be reliably pushed forward from its initial position by the rear connecting portion 34C.

[0103] 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.

[0104] 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.

[0105] 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).

[0106] 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.

[0107] 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.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] <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.

[0112] 14, the second embodiment differs from the first embodiment only in that the extrusion structure is configured not with a rear connecting portion 34C as an extrusion chamber that connects (interconnects) the rear ends of a pair of front and rear chambers 34 (front and rear extending portions 34A) in the left-right direction, but with an extrusion chamber 35 that is separate from the pair of front and rear chambers 34. That is, a cylindrical root portion 38 extending rearward is formed integrally with the center in the sheet width direction on the rear surface of the extrusion chamber 35, and an outlet 48A of a branch pipe 48 is connected to the root portion 38.

[0113] Therefore, the same effects as those of the first embodiment can be obtained, and the airbag body 40 folded into a roll is reliably pushed forward from the initial position (mounted position) by the push-out chamber 35. In addition, in this second embodiment, the push-out chamber 35 is configured separately from the pair of front and rear chambers 34, so that the configuration of the airbag 32 can be simplified. In other words, the push-out chamber 35 also constitutes the airbag 32.

[0114] <Third embodiment> Next, an airbag device 30 according to a third embodiment will be described. Note that the same reference numerals are used for the same parts as those in the first and second embodiments, and detailed descriptions (including common functions) will be omitted as appropriate.

[0115] As shown in FIG. 15, in the third embodiment, two inflators 44 are provided, a first inflator 44B that supplies gas to the pair of front and rear chambers 34, and a second inflator 44C that supplies gas to the rear connecting portion 34C (or the extrusion chamber 35 shown in FIG. 14), and the vehicle seat 12 is provided with a first distribution pipe 51 that can supply gas ejected from the first inflator 44B to the pair of front and rear chambers 34, and a second distribution pipe 53 that can supply gas ejected from the second inflator 44C to the rear connecting portion 34C (or the extrusion chamber 35). This is the only difference from the first and second embodiments described above.

[0116] The first distribution pipe 51 is formed in a substantially "T" shape in a front view, and has a cylindrical branch pipe 51L branched from the center in the seat width direction to the left, and a cylindrical branch pipe 51R branched from the center in the seat width direction to the right. The outlets 51A of the left and right branch pipes 51L and 51R are connected to the bases 36L and 36R of the pair of front and rear chambers 34. The outlet of the inflator 44B is connected to a cylindrical base extending downward from the center in the seat width direction of the first distribution pipe 51.

[0117] The second distribution pipe 53 is disposed at approximately the center in the seat width direction of the headrest 18, and extends upward from approximately the same position as the center in the seat width direction of the first distribution pipe 51 in a front view. An outlet 53A, which is an upper end portion of the second distribution pipe 53, is connected to the base portion 38 of the rear connecting portion 34C (or the extrusion chamber 35). An outlet of the inflator 44C is connected to a cylindrical base portion extending downward from the center in the seat width direction of the second distribution pipe 53, and the inflator 44C is disposed at approximately the same height as the inflator 44B.

[0118] Further, the inner diameter of each of the outlets 51A of the left and right branch pipes 51L, 51R in the first distribution pipe 51 is made larger than the inner diameter of the outlet 53A of the second distribution pipe 53. As a result, as in the first and second embodiments, the amount of gas supplied to the pair of front and rear chambers 34 can be made larger than the amount of gas supplied to the rear connecting portion 34C (or the extrusion chamber 35), and therefore the airbag body 40 can be inflated and deployed more quickly.

[0119] Furthermore, according to the third embodiment, since only two inflators 44, the first inflator 44B and the second inflator 44C, are provided, the number of parts and mounting space can be reduced, and manufacturing costs can be reduced, compared to a case in which two inflators are provided for the pair of front and rear chambers 34 and one inflator is provided for the rear connecting portion 34C (or the extrusion chamber 35).

[0120] <Fourth embodiment> Next, an airbag device 30 according to a fourth embodiment will be described. Note that the same reference numerals are used for the same parts as those in the first and second embodiments, and detailed descriptions (including common functions) will be omitted as appropriate.

[0121] As shown in FIG. 16, in this fourth embodiment, the extrusion structure differs from the first and second embodiments only in that it is composed of an extrusion cloth 26 that connects the pair of front and rear chambers 34 to each other, rather than a rear connecting portion 34C that serves as an extrusion chamber that connects (connects) the rear ends of the pair of front and rear chambers 34 (front and rear extending portions 34A) in the left-right direction (connects them to each other) or an extrusion chamber 35 that is separate from the pair of front and rear chambers 34.

[0122] The extruded cloth 26 is formed in a rectangular shape with the seat width direction as viewed from behind as its longitudinal direction, and is formed to be approximately the same size as the rear connecting portion 34C. The extruded cloth 26 is made of, for example, a polyamide or polyester cloth material, and both ends in the seat width direction are sewn and attached to predetermined positions on the rear side of the base cloth 34D (see FIG. 5(B)) on the inner side in the seat width direction of the pair of front and rear chambers 34 (front and rear extending portions 34A).

[0123] Therefore, when the pair of front and rear chambers 34 inflate and deploy forward (specifically, forward and outward in the seat width direction), a predetermined tension is applied to the extrusion cloth 26 in the seat width direction. Therefore, the airbag body 40 folded in a roll shape is reliably extruded forward from the initial position (mounting position) by the extrusion cloth 26. In addition, in this fourth embodiment, since the extrusion structure is formed by the extrusion cloth 26, the airbag 32 can be stored compactly and made lighter.

[0124] As described above, in the fourth embodiment, the rear connecting portion 34C and the extrusion chamber 35 are not provided. Therefore, in the fourth embodiment, the branch pipe 48 in the distribution pipe 50 is not required. In other words, in the fourth embodiment, for example, only the first distribution pipe 51 shown in FIG. 15 is provided.

[0125] <Fifth embodiment> Next, an airbag device 30 according to a fifth embodiment will be described. Note that the same reference numerals are used for the same parts as those in the first and second embodiments, and detailed descriptions (including common functions) will be omitted as appropriate.

[0126] As shown in Fig. 17, the fifth embodiment differs from the first and second embodiments only in that three inflators 44 are provided so as to be capable of supplying gas to each of the pair of front and rear chambers 34 and the rear connecting portion 34C (or the extrusion chamber 35 shown in Fig. 14). That is, the nozzles of the inflators 44L, 44R are directly connected to the respective root portions 36L, 36R of the pair of front and rear chambers 34, and the nozzle of the inflator 44D is directly connected to the root portion 38 of the rear connecting portion 34C (or the extrusion chamber 35).

[0127] Therefore, in this fifth embodiment, the distribution pipe 50 is not required, but the three inflators 44L, 44R, 44D are configured to protrude in a direction intersecting the extending direction of the seat back 16 (rearward and downward) in a side view (not shown). Also, in this fifth embodiment, the output of the two inflators 44L, 44R that supply gas to the pair of front and rear chambers 34, respectively, is set to be higher than the output of the one inflator 44D that supplies gas to the rear connecting portion 34C (or the extrusion chamber 35).

[0128] Therefore, in this fifth embodiment, the headrest 18 and the seat back 16 are enlarged (thicker), but similar to the first to third embodiments described above, the amount of gas supplied to the pair of front and rear chambers 34 can be increased more than the amount of gas supplied to the rear connecting portion 34C (or the extrusion chamber 35), thereby enabling the airbag body 40 to complete inflation and deployment more quickly.

[0129] Sixth embodiment Next, an airbag device 30 according to a sixth 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.

[0130] 18, the sixth embodiment differs from the first embodiment only in that, instead of folding the tip portions 34F of the pair of front and rear chambers 34 once, a valve mechanism 60 that instantaneously blocks the inflow of gas is provided at the tip portions 34F. The valve mechanism 60 has a cylindrical valve body 62 whose inner diameter gradually decreases, and the valve body 62 is made of, like the base fabric of the airbag 32, a fabric material such as a polyamide or polyester material.

[0131] Each valve body 62 is attached by sewing its maximum inner diameter portion 62A around the entire circumference to the inner circumferential surface at the tip portion 34F of each front and rear chamber 34. Each valve body 62 is disposed inside each front and rear chamber 34 with its minimum inner diameter portion 62B facing upstream in the gas inflow direction.

[0132] With the valve body 62 configured in this manner, when gas flows in in the direction of arrow E, as shown in FIG. 19(A), the minimum inner diameter portion 62B of the valve body 62 bends toward the center of the valve body 62, instantaneously blocking the inside of each of the front and rear chambers 34, as shown in FIG. 19(B).

[0133] When gas further flows in in the direction of arrow E, the minimum inner diameter portion 62B of the valve body 62 passes over the maximum inner diameter portion 62A from the inside, turns around, and is positioned downstream in the direction of gas flow, as shown in Fig. 19(C). This opens the inside of each of the front and rear chambers 34, and gas is supplied from the tip end 34F of each of the front and rear chambers 34 to the airbag body 40 folded in a roll.

[0134] As described above, according to the sixth embodiment, the valve mechanism 60 that instantaneously blocks the inflow of gas is provided at the tip portions 34F of the pair of front and rear chambers 34, so that gas can be controlled not to flow into the airbag body 40 until it moves forward through a gap between the head H of the occupant D and the ceiling 28 of the vehicle compartment. Therefore, the airbag body 40 can move forward reliably and quickly, and as a result, the airbag body 40 can be inflated and deployed more quickly.

[0135] Seventh embodiment Finally, an airbag device 30 according to a seventh 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.

[0136] As shown in Figures 20 and 21(A), this seventh embodiment also differs from the first embodiment in that, instead of folding the tip portions 34F of the pair of front and rear chambers 34 into a roll just once, a valve mechanism 60 that instantaneously blocks the inflow of gas is provided at the tip portions 34F.

[0137] This valve mechanism 60 is composed of a tape-like temporary fastening member 64 that is attached by sewing only the upper and lower ends together with the upper and lower peripheral edges when the upper and lower peripheral edges of two long pieces of base fabric are sewn together to form the front and rear chambers 34. Like the base fabric of the airbag 32, this temporary fastening member 64 is also made of a cloth material such as a polyamide or polyester material.

[0138] With this temporary fastening member 64, by inserting a portion of the tip 34F of each of the front and rear chambers 34, which has been flattened, upstream of the temporary fastening member 64 in the gas inflow direction between the temporary fastening member 64 and the base fabric 34D which faces the temporary fastening member 64 in the seat width direction, the inside of each of the front and rear chambers 34 can be instantly sealed, as shown in Figure 21 (A).

[0139] When gas further flows in the direction of arrow E, a part of each of the front and rear chambers 34 inserted between the temporary fastening member 64 and the base fabric 34D is removed from there, and the inside of each of the front and rear chambers 34 is opened as shown in Fig. 21(B). That is, gas is supplied from the tip end 34F of each of the front and rear chambers 34 to the airbag main body 40 folded into a roll.

[0140] As described above, according to the seventh embodiment, the valve mechanism 60 that instantaneously blocks the inflow of gas is provided at the tip portions 34F of the pair of front and rear chambers 34, so that gas can be controlled not to flow into the airbag body 40 until it moves forward through a gap between the head H of the occupant D and the ceiling 28 of the vehicle compartment. Therefore, the airbag body 40 can move forward reliably and quickly, and as a result, the airbag body 40 can be inflated and deployed more quickly.

[0141] The seat-mounted airbag device 30 and the folding method of the airbag 32 according to this embodiment have been described above with reference to the drawings, but the seat-mounted airbag device 30 and the folding method of the airbag 32 according to this embodiment are not limited to those shown in the drawings, and can be appropriately modified in design without departing from the gist of the present invention. For example, the extrusion structure is not limited to that shown in the drawings.

[0142] Furthermore, when folding the airbag 32, it may be folded, for example, on a mount (not shown) on which a reference line serving as a reference for folding is drawn. Furthermore, the number of roll folds and bellows folds in the pair of front and rear chambers 34 is not particularly limited as long as it is possible to speed up the completion of inflation and deployment of the airbag body 40. Furthermore, in the case of a vehicle in which the gap between the head H of the occupant D and the ceiling 28 of the vehicle compartment is relatively wide, the airbag body 40 may be folded inward in a roll shape, which is the opposite of the above embodiment.

[0143] However, it is preferable that the tip portions 34F of the pair of front and rear chambers 34 are rolled outward. With this, even if the airbag body 40 in a rolled-up state hits the rear upper end of the head H of the occupant D when it moves forward as the pair of front and rear chambers 34 are inflated and deployed, the airbag body 40 in the rolled-up state can move forward while rolling over the rear upper end of the head H of the occupant D in that state.

[0144] The distribution pipes 50, 51, 53 may be provided straddling between the inside of the headrest 18 and the inside of the seat back 16. In the first embodiment, for example, the base portions 36, 38 are shown attached by being inserted into the inside of the respective ejection ports 46A, 48A, but the present invention is not limited to this, and the base portions 36, 38 may be attached by being placed over the outside of the respective ejection ports 46A, 48A. [Explanation of symbols]

[0145] 12 Vehicle seats 16 Seat back 18 Headrest 26 Extruded fabric (extruded structure) 28 Ceiling 30 Airbag device 32 Airbag 34 Front and rear chambers 34C Rear connection part (extrusion chamber / extrusion structure) 35 Extrusion chamber (extrusion structure) 40 Airbag body 44 Inflator 44B First Inflator 44C Second Inflator 50 minutes plumbing 51 1st branch pipe 53 2nd branch pipe 60 Valve mechanism 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: The seat-mounted airbag device has an extrusion structure on the seat rear side of the airbag body for extruding the airbag body toward the seat front side.

2. 2. The seat-mounted airbag device according to claim 1, wherein the extrusion structure is formed of an extrusion chamber that interconnects the pair of front and rear chambers.

3. 2. The seat-mounted airbag device according to claim 1, wherein the pushing structure is formed of a pushing chamber separate from the pair of front and rear chambers.

4. 2. The seat-mounted airbag device according to claim 1, wherein said extruded structure is comprised of an extruded fabric interconnecting said pair of front and rear chambers.

5. a single inflator is provided, and a distribution pipe capable of supplying gas ejected from the inflator to the pair of front and rear chambers and the extrusion chamber is provided in the vehicle seat; 4. The seat-mounted airbag device according to claim 2, wherein an inner diameter of the outlet of the distribution pipe connected to the root portion of the pair of front and rear chambers is larger than an inner diameter of the outlet of the distribution pipe connected to the root portion of the extrusion chamber.

6. The headrest of the vehicle seat is integrally formed with the seat back of the vehicle seat, 6. The seat-mounted airbag device according to claim 5, wherein the inflator is disposed along an extending direction of the seat back.

7. the inflator is provided with two inflators, a first inflator that supplies gas to the pair of front and rear chambers and a second inflator that supplies gas to the extrusion chamber, and the vehicle seat is provided with a first distribution pipe that can supply the gas ejected from the first inflator to the pair of front and rear chambers and a second distribution pipe that can supply the gas ejected from the second inflator to the extrusion chamber, 4. The seat-mounted airbag device according to claim 2, wherein an inner diameter of the outlet of the first distribution pipe connected to the root portion of the pair of front and rear chambers is larger than an inner diameter of the outlet of the second distribution pipe connected to the root portion of the extrusion chamber.

8. The headrest of the vehicle seat is integrally formed with the seat back of the vehicle seat, 8. The seat-mounted airbag device according to claim 7, wherein the first inflator and the second inflator are disposed along an extending direction of the seat back.

9. The inflator is provided in three units so as to be capable of supplying gas to the pair of front and rear chambers and the extrusion chamber, respectively; 4. The seat-mounted airbag device according to claim 2, wherein the outputs of the two inflators which supply gas to the pair of front and rear chambers respectively are set to be higher than the output of the one inflator which supplies gas to the extrusion chamber.

10. 5. The seat-mounted airbag device according to claim 1, wherein a valve mechanism for instantaneously blocking the inflow of the gas is provided at the tip end of the pair of front and rear chambers.

11. A method for folding 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 left and right sides of the head of an occupant seated in the vehicle seat when gas is supplied from an inflator provided in the vehicle seat in the event of a vehicle collision, and an airbag body which moves toward the front of the seat through a gap between the occupant's head and a ceiling of a vehicle compartment 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 the gas being supplied from the pair of front and rear chambers, a deployment step of flattening the airbag; A drawing process of drawing out a base fabric on an outer side of the airbag body in the seat width direction to the outer side in the seat width direction; The method for folding an airbag comprising the steps of:

12. a roll folding process for folding the leading ends of the pair of front and rear chambers in a roll-like manner from the front side of the sheet toward the upper side of the sheet a predetermined number of times; a bellows folding process of folding the pair of front and rear chambers excluding the tip portions in a bellows-like manner a plurality of times; 12. The method of claim 11, further comprising:

13. The airbag folding method according to claim 12, wherein the roll folding step includes one roll folding.

14. 14. The airbag folding method according to claim 12 or 13, wherein the bellows-folding step includes folding the airbag in the bellows-folding direction three times.

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