Seat-mounted airbag device and airbag folding method

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-attached airbag device and an airbag folding method.

Background Art

[0002] An airbag device provided with an airbag having a rear inflation part that expands on the back side of the seat, a pair of side inflation parts that extend forward from both the left and right sides of the rear inflation part, and a pair of front inflation parts that extend from the side inflation parts to the center side and are connected to each other at the center side to cover the front of the occupant has been conventionally known (see, for example, Patent Document 1).

[0003] [[ID=??]] Also, an airbag device provided with a bag body having a body support part that expands from behind the occupant's head to the front of the occupant and a pair of head support parts that expand on both the left and right sides of the occupant's head and are connected to the body support part has also been conventionally known (see, for example, Patent Document 2). In this bag body, in the deployed state, an escape part is formed that penetrates vertically between the pair of head support parts and avoids the occupant's head.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the airbag device as described above, the airbag body is disposed on the front side of the occupant by expanding and deploying through the gap between the occupant's head and the ceiling from the seat back. Therefore, it is desired that the airbag body remains small without allowing gas to flow in until it passes over the occupant's head, and then allows gas to flow in and expand after passing over the occupant's head. It seems there is a formatting issue with the "??" in the original text. If you can clarify that part, it will be possible to provide a more accurate translation.

[0006] However, when gas is introduced to inflate the airbag after it has passed over the occupant's head, the time it takes for the airbag to fully inflate and deploy tends to be longer. Thus, there is still room for improvement in achieving both improved airbag deployment performance in the gap between the occupant's head and the ceiling, and faster completion of airbag inflation and deployment.

[0007] Therefore, the present invention aims to provide a seat-mounted airbag device and a method for folding the airbag, which can improve the deployment performance of the airbag body positioned in front of the occupant's seat by inflating and deploying through the space between the occupant's head and the ceiling of the vehicle cabin, and to expedite the time until inflation and deployment are completed. [Means for solving the problem]

[0008] To achieve the above objective, a seat-mounted airbag device according to a first embodiment of the present invention is provided on a vehicle seat and comprises an airbag having an inflator that ejects gas in the event of a vehicle collision, a pair of front and rear chambers that, when supplied with the gas ejected from the inflator, inflate and deploy toward the front of the seat, passing on both the left and right sides of the head of an occupant seated on the vehicle seat, and an airbag body that moves toward the front of the seat, passing between the occupant's head and the ceiling of the vehicle compartment, and inflates and deploys toward the rear of the seat between the pair of front and rear chambers as the pair of front and rear chambers inflate and deploy, and is positioned toward the front of the seat of the occupant, and the airbag has an extrusion structure on the rear side of the seat of the airbag body that pushes the airbag body toward the front of the seat.

[0009] According to the first embodiment of the invention, when a vehicle collision occurs, gas ejected from the inflator is supplied to a pair of front and rear chambers, and these chambers inflate and deploy towards the front of the seat, passing on both sides of the head of the occupant seated in the vehicle seat. As the pair of front and rear chambers inflate and deploy, the airbag body moves towards the front of the seat, passing between the head of the occupant seated in the vehicle seat and the ceiling of the vehicle compartment. As gas is supplied from the pair of front and rear chambers, the airbag body inflates and deploys towards the rear of the seat between the pair of front and rear chambers, and is positioned in front of the occupant's seat. In other words, because the airbag body inflates and deploys with a delay compared to the pair of front and rear chambers, it can reliably move between the occupant's head and the ceiling of the vehicle compartment.

[0010] Furthermore, this airbag has an extrusion structure on the rear side of the airbag body that pushes the airbag body forward towards the seat. Therefore, the airbag body is forcibly pushed forward towards the seat from its initial position (mounting position) by this extrusion structure. Consequently, in the event of a vehicle collision, the time the airbag body remains in its initial position is shortened, and the inflation and deployment of the airbag body is expedited.

[0011] In other words, according to the present invention, by inflating and deploying through the space between the occupant's head and the ceiling of the vehicle cabin, it is possible to improve the deployment performance of the airbag body, which is positioned in front of the occupant's seat, and to expedite the time until inflation and deployment are completed. It should be noted that "at the time of collision" as used here also includes when the inevitability of a collision is predicted (foreseen).

[0012] Furthermore, a second embodiment of the present invention is a seat-mounted airbag device according to the first embodiment, wherein the extrusion structure is composed of an extrusion chamber that connects the pair of front and rear chambers to each other.

[0013] According to the second embodiment of the invention, the extrusion structure is composed of an extrusion chamber that connects a pair of front and rear chambers to each other. Therefore, the airbag body is reliably pushed out from its initial position (mounting position) toward the front of the seat by the extrusion chamber.

[0014] Furthermore, a third embodiment of the seat-mounted airbag device according to the present invention is a seat-mounted airbag device according to the first embodiment, wherein the extrusion structure is composed of an extrusion chamber separate from the pair of front and rear chambers.

[0015] According to the third embodiment of the invention, the extrusion structure is composed of an extrusion chamber separate from the pair of front and rear chambers. Therefore, the airbag body is reliably pushed out from its initial position (mounting position) toward the front of the seat by the extrusion chamber. Furthermore, since this extrusion chamber is composed separately from the pair of front and rear chambers, the structure of the airbag is simplified.

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

[0017] According to the fourth embodiment of the invention, the extrusion structure is composed of an extruded fabric that connects a pair of front and rear chambers to each other. Therefore, when the pair of front and rear chambers move toward the front of the seat, tension is applied to this extruded fabric in the seat width direction. Consequently, the airbag body is reliably pushed toward the front of the seat from its initial position (mounting position) by this extruded fabric. Furthermore, because the extrusion structure is composed of an extruded fabric, it can be stored compactly and the airbag is made lighter.

[0018] Furthermore, a fifth embodiment of the seat-mounted airbag device according to the present invention is a seat-mounted airbag device according to the second or third embodiment, wherein the inflator is provided as a single unit, and the vehicle seat is provided with distribution pipes 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 nozzle of the distribution pipe connected to the base of the pair of front and rear chambers is larger than the inner diameter of the nozzle of the distribution pipe connected to the base of the extrusion chamber.

[0019] According to the fifth embodiment of the invention, a single inflator is provided, and the gas ejected from the inflator is supplied to a pair of front and rear chambers and an extrusion chamber, respectively, 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 for the extrusion chamber, the number of parts and mounting space are reduced, and manufacturing costs are lowered.

[0020] Furthermore, the inner diameter of the nozzle of the distribution pipe connected to the base of the pair of front and rear chambers is larger than the inner diameter of the nozzle of the distribution pipe connected to the base of the extrusion chamber. As a result, the amount of gas supplied to the pair of front and rear chambers increases compared to the amount of gas supplied to the extrusion chamber, thus accelerating the completion of inflation and deployment of the airbag body.

[0021] Furthermore, a seat-mounted airbag device according to a sixth embodiment of the present invention is a seat-mounted airbag device according to a fifth embodiment, wherein the headrest of the vehicle seat is formed integrally with the seat back of the vehicle seat, and the inflator is arranged along the extending direction of the seat back.

[0022] According to the sixth embodiment of the invention, the headrest is formed integrally with the seatback. Therefore, compared to the case where the headrest is separate from the seatback, the airbag is prevented from becoming detached from the vehicle seat. In addition, the inflator is positioned along the extending direction of the seatback. Therefore, compared to the case where the inflator is positioned along a direction intersecting the extending direction of the seatback, the enlargement (increase in thickness) of the headrest and seatback is suppressed.

[0023] Further, the seat-mounted airbag device according to the seventh aspect of the present invention is the seat-mounted airbag device according to the second or third aspect, wherein the inflator is provided with two inflators, namely, 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. A first distribution pipe capable of supplying the gas ejected from the first inflator to the pair of front and rear chambers and a second distribution pipe capable of supplying the gas ejected from the second inflator to the extrusion chamber are provided on the vehicle seat. The inner diameter of the ejection port of the first distribution pipe connected to the root portion of the pair of front and rear chambers is larger than the inner diameter of the ejection port of the second distribution pipe connected to the root portion of the extrusion chamber.

[0024] According to the invention of the seventh aspect, two inflators are provided, namely, 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. 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 with 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] Further, the inner diameter of the ejection port of the first distribution pipe connected to the root portion of the pair of front and rear chambers is larger than the inner diameter of the ejection port of the second distribution pipe connected to the root portion of the extrusion chamber. Therefore, the amount of gas supplied to the pair of front and rear chambers is increased compared with the amount of gas supplied to the extrusion chamber, and the early completion of the inflation and deployment of the airbag body can be achieved.

[0026] Further, the seat-mounted airbag device according to the eighth aspect of the present invention is the seat-mounted airbag device according to the seventh aspect, wherein the headrest of the vehicle seat is integrally formed with the 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 seatback. Therefore, compared to the case where the headrest is separate from the seatback, the airbag is prevented from becoming detached from the vehicle seat. In addition, the first inflator and the second inflator are arranged along the extending direction of the seatback. Therefore, compared to the case where the first inflator and the second inflator are arranged along a direction intersecting the extending direction of the seatback, the enlargement (increase in thickness) of the headrest and seatback is suppressed.

[0028] Furthermore, a seat-mounted airbag device according to a ninth aspect of the present invention is a seat-mounted airbag device according to a second or third aspect, wherein three inflators are provided to supply gas to the pair of front and rear chambers and the extrusion chamber, respectively, and the output of the two inflators that supply gas to the pair of front and rear chambers is higher than the output of the one inflator that supplies gas to the extrusion chamber.

[0029] According to the ninth aspect of the invention, three inflators are provided, each capable of supplying gas to a pair of front and rear chambers and an extrusion chamber. The output of the two inflators supplying gas to the pair of front and rear chambers is 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, thus accelerating the completion of inflation and deployment of the airbag body.

[0030] Furthermore, the tenth embodiment of the present invention is a seat-mounted airbag device according to any one of the first to ninth embodiments, wherein a valve mechanism for instantaneously blocking the inflow of the gas is provided at the tip of the pair of front and rear chambers.

[0031] According to the tenth embodiment of the invention, a valve mechanism is provided at the tip of a pair of front and rear chambers to instantaneously block the inflow of gas. This makes it possible to control the inflow of gas to the airbag body until it moves towards the front of the seat, passing between the occupant's head and the ceiling of the vehicle. Therefore, the airbag body can be reliably moved towards the front of the seat, and as a result, the inflation and deployment of the airbag body can be expedited.

[0032] Furthermore, an airbag folding method according to the 11th aspect of the present invention is an airbag folding method comprising: a pair of front and rear chambers that inflate and unfold toward the front of the seat by passing on both the 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 when the vehicle is in collision; and an airbag body that moves toward the front 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 unfold toward the rear of the seat between the pair of front and rear chambers and is positioned toward the front of the seat of the occupant as the gas is supplied from the pair of front and rear chambers, the method comprising: an unfolding step of flattening the airbag; and an unfolding step of pulling out the base fabric on the outside in the seat width direction of the airbag body toward the outside in the seat width direction.

[0033] According to the eleventh embodiment of the invention, when the airbag is folded, it is flattened by the deployment process, and the base fabric on the outside of the airbag body in the seat width direction is pulled outwards in the seat width direction by the withdrawal process. Therefore, the thickness due to the overlapping of the airbag base fabric is reduced, and the thickness of the airbag body is reduced, which improves the deployment performance of the airbag body as it moves towards the front of the seat, passing between the occupant's head and the ceiling of the vehicle. In other words, the airbag body can be reliably moved towards the front of the seat, and as a result, the time until the inflation and deployment of the airbag body is completed can be shortened.

[0034] Furthermore, a twelfth aspect of the airbag folding method according to the present invention is a method for folding an airbag according to the eleventh aspect, comprising a roll folding step of rolling the front ends of the pair of front and rear chambers a predetermined number of times from the front side of the seat towards the top side of the seat, and a bellows folding step of folding the pair of front and rear chambers, excluding the front ends, multiple times in a bellows-like manner.

[0035] According to the twelfth aspect of the invention, the front ends of a pair of front and rear chambers are roll-folded a predetermined number of times from the front side of the sheet towards the top side of the sheet by a roll-folding process, and the pair of front and rear chambers, excluding the front ends, are bellows-folded multiple times by a bellows-folding process.

[0036] Here, it is known that bellows folding deploys faster than roll folding. Therefore, the pair of front and rear chambers inflate and deploy early, except for their leading edges. Furthermore, the leading edges of the pair of front and rear chambers are controlled not to inflate and deploy until the airbag body has moved towards the front of the seat, passing between the occupant's head and the ceiling of the vehicle. This ensures that the airbag body moves reliably towards the front of the seat, and as a result, the inflation and deployment of the airbag body is expedited.

[0037] Furthermore, the thirteenth aspect of the airbag folding method according to the present invention is the airbag folding method according to the twelfth aspect, wherein the number of roll folds in the roll folding step is one.

[0038] According to the 13th embodiment of the invention, in the roll folding process, the number of roll folds at the tip of the pair of front and rear chambers is 1. Here, if the number of roll folds is, for example, 0.5 times, gas begins to flow into the airbag body before the airbag body moves to the front of the seat through the space between the occupant's head and the ceiling of the vehicle, making it difficult for the airbag body to move to the front of the seat through the space between the occupant's head and the ceiling of the vehicle. On the other hand, if the number of roll folds is, for example, 1.5 times, the inflow of gas from the tip of the pair of front and rear chambers into the airbag body is delayed after the airbag body has moved to the front of the seat, so the inflation and deployment of the airbag body toward the rear of the seat is delayed.

[0039] In contrast, because the roll-folding is performed only once, gas does not begin to flow into the airbag before it moves from the space between the occupant's head and the ceiling of the vehicle towards the front of the seat. This makes it easier for the airbag to move from the space between the occupant's head and the ceiling of the vehicle towards the front of the seat. Furthermore, once the airbag has moved towards the front of the seat, gas flows into the airbag from the tips of the pair of front and rear chambers more quickly, resulting in faster inflation and deployment of the airbag towards the rear of the seat. This allows for faster completion of the airbag's inflation and deployment.

[0040] Furthermore, the 14th embodiment of the present invention is the airbag folding method of the 12th or 13th embodiment, wherein the number of bellows folds in the bellows folding step is 3.

[0041] According to the 14th embodiment of the invention, in the bellows folding process, the pair of front and rear chambers are folded three times. Therefore, compared to the case where the number of bellows folds is four or more times, the pair of front and rear chambers expand and unfold earlier, except for their leading edges. [Effects of the Invention]

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

[0043] [Figure 1] This is a schematic perspective view showing the airbag of the seat-mounted airbag device according to the first embodiment in an inflated and deployed state. [Figure 2] This is a schematic side view showing the airbag of the seat-mounted airbag device according to the first embodiment in an inflated and deployed state. [Figure 3] This is a schematic plan view showing the airbag of the seat-mounted airbag device according to the first embodiment in an inflated and deployed state. [Figure 4] This is a schematic plan view showing the shape of the airbag before it is folded in the first embodiment. [Figure 5] (A) This is a schematic enlarged cross-sectional view taken along the line XX in Figure 4. (B) This is a schematic enlarged cross-sectional view taken along the line YY in Figure 4. [Figure 6] (A) to (F) are schematic plan views showing the airbag folding process in the first embodiment. [Figure 7] This is a schematic plan view showing the shape of the airbag after it has been folded in the first embodiment. [Figure 8] This is a schematic front view showing a partial cross-section of the airbag housed in the headrest in the first embodiment. [Figure 9] (A) A schematic front view showing the shape of the distribution pipe in the first embodiment, with the airbag omitted in a partial cross-section. (B) A schematic side view showing the airbag housed in the headrest in the first embodiment, with a partial cross-section. [Figure 10] (A) to (C) are schematic plan views showing the process during the initial stages of airbag inflation and deployment in the first embodiment. [Figure 11] This is a schematic side view showing the initial stage of airbag inflation and deployment in the first embodiment. [Figure 12]This is a schematic side view showing the airbag during the mid-stage of inflation and deployment in the first embodiment. [Figure 13] This is a schematic side view showing the airbag in the later stages of inflation and deployment in the first embodiment. [Figure 14] (A) to (C) are schematic plan views showing the process during the initial stages of airbag inflation and deployment in the second embodiment. [Figure 15] (A) A schematic front view showing the shape of the distribution pipe in the third embodiment, with the airbag omitted in a partial cross-section. (B) A schematic side view showing the airbag housed in the headrest in the third embodiment, with a partial cross-section. [Figure 16] (A) to (C) are schematic plan views showing the initial stages of airbag inflation and deployment in the fourth embodiment. [Figure 17] (A) to (C) are schematic plan views showing the initial stages of airbag inflation and deployment in the fifth embodiment. [Figure 18] This is a schematic perspective view showing the valve mechanism in the sixth embodiment. [Figure 19] (A) to (C) are schematic cross-sectional views taken along the ZZ line in Figure 18, showing the operation of the valve mechanism in the sixth embodiment. [Figure 20] This is a schematic side view showing the valve mechanism in the seventh embodiment. [Figure 21] (A) and (B) are schematic cross-sectional views showing the operation of the valve mechanism in the seventh embodiment. [Modes for carrying out the invention]

[0044] The embodiments of the present invention will be described in detail below with reference to the drawings. For the sake of explanation, in each figure, the arrow UP indicates the upward direction of the vehicle and vehicle seat, the arrow FR indicates the forward direction of the vehicle and vehicle seat, the arrow RH indicates the rightward direction of the vehicle and vehicle seat, and the arrow LH indicates the leftward direction of the vehicle and vehicle seat. Therefore, in the following description, when the directions of up and down, front and back, and left and right are mentioned without further specification, they refer to the up and down, front and back, and left and right directions of the vehicle and vehicle seat. Also, the left and right directions are synonymous with the vehicle width direction and the seat width direction.

[0045] <First Embodiment> First, the seat-mounted airbag device (hereinafter simply referred to as "airbag device") 30 according to the first embodiment will be described. As shown in Figure 1, the occupant protection device 10 consists of a vehicle seat 12 and an airbag device 30. The vehicle seat 12 is either the front seat or the rear seat of the vehicle (automobile). Here, the rear seat is referred to as the vehicle seat 12, rather than the front seat 13 (see Figures 11 to 13).

[0046] Furthermore, Figures 1 to 3 show a crash test dummy (human body dummy) seated in the vehicle seat 12 as a model of the occupant (seater) to be protected. The dummy is, for example, an AM50 (50th percentile of an adult American male) dummy for frontal crash tests (Hybrid III). The dummy is seated in the standard seating position specified in the crash test method, and the vehicle seat 12 is positioned in the standard setting position corresponding to the seating position. Hereafter, the dummy will be referred to as "occupant D".

[0047] The vehicle seat 12 includes a seat cushion 14 on which the occupant D sits (supporting the occupant D's buttocks and thighs F), and a seat back 16 that extends upward to the rear side of the seat cushion 14 in a side view from the seat width direction, and is provided so as to be rotatable in the axial direction of the seat width direction, and supports the back of the occupant D. The seat back 16 has an integrated headrest 18 at the center of its upper end in the seat width direction that supports the occupant D's head H. The rear wall of the headrest 18 is made of a backboard 19 (see Figure 9(B)).

[0048] As shown in Figures 1 to 3, occupant D, seated on the seat cushion 14 of the vehicle seat 12, is restrained to the vehicle seat 12 by a seat belt 22 provided by the seat belt device 20. The seat belt device 20 is a three-point seat belt device, a so-called seat-mounted seat belt device in which a retractor and anchor (not shown) and a buckle are each provided on the vehicle seat 12.

[0049] The airbag system 30 comprises an airbag 32 and a single inflator 44 (see Figure 9). The airbag 32 is normally stored inside the headrest 18 in a folded state (see Figures 8, 9(B), and 10(A)). The inflator 44 is a cylindrical type formed in a substantially cylindrical shape, for example, by combustion or cold gas, and is installed along the extending direction of the seatback 16 (with the axial direction in the vertical direction), either inside the seatback 16 or spanning from inside the seatback 16 to inside the headrest 18.

[0050] Furthermore, the airbag system 30 is equipped with a control unit (ECU), not shown, which controls the operation of the inflator 44. The control unit is electrically connected to the inflator 44 and collision sensors (including cameras, etc.), not shown, and is configured to detect a frontal collision of the vehicle or predict the inevitability of a frontal collision. Based on information from the collision sensors, the control unit is configured to activate the inflator 44 when it detects or predicts a frontal collision of the vehicle.

[0051] In other words, the inflator 44 is activated by the control device when a frontal collision of a vehicle is detected or predicted (hereinafter sometimes referred to as "at the time of a frontal collision of a vehicle"), generating gas and ejecting it from the nozzle 44A (see Figure 9). The types of frontal collisions of a vehicle that trigger the control device to activate the inflator 44 include not only full-wrap frontal collisions but also offset frontal collisions such as oblique collisions and minute-wrap collisions.

[0052] The airbag 32 is supplied with gas ejected from the inflator 44, which causes it to deploy and inflate forward, passing from the front of the headrest 18 to both sides of the head H of the occupant D seated in the vehicle seat 12, and above the head H of the occupant D. Specifically, the airbag 32 has a pair of front and rear chambers 34 and an airbag body 40.

[0053] As shown in Figure 4, the pair of front and rear chambers 34 have a pair of front and rear extending sections 34A that expand and extend forward through both sides of the occupant D's head H as gas is supplied from the inflator 44, a front connecting section 34B (see Figures 1 to 3) that connects the front ends of the pair of front and rear extending sections 34A in the left-right direction, and a rear connecting section 34C that connects (connects to each other) the rear ends of the pair of front and rear extending sections 34A in the left-right direction. This rear connecting section 34C is the "extrusion chamber" and is located on the rear side of the airbag body 40.

[0054] The front connecting portion 34B is formed in a bag-like shape that is roughly "T" shaped in a front view, continuous with the pair of front and rear extending portions 34A (see Figures 1 to 3). Furthermore, cylindrical root portions 36 extending to the rear are integrally formed at the rear ends of the pair of front and rear chambers 34 (front and rear extending portions 34A), in other words, at both ends in the sheet width direction on the rear surface of the rear connecting portion 34C, and a cylindrical root portion 38 extending to the rear is also integrally formed at the center in the sheet width direction on the rear surface of the rear connecting portion 34C.

[0055] In the following, the left base portion 36 may be referred to as "base portion 36L" and the right base portion 36 as "base portion 36R". Furthermore, the left and right base portions 36 and the central base portion 38 are connected to the respective outlets 46A and 48A of the branch pipes 46 and 48 of the distribution piping (diffuser) 50, which will be described later. The front and rear chambers 34 are formed into a long bag-like (tubular) shape by overlapping two long pieces of base fabric and sewing their upper and lower edges together (see Figure 5(B)).

[0056] As the pair of front and rear chambers 34 (front and rear extensions 34A) inflate and deploy, the airbag body 40 moves forward, passing between the occupant D's head H and the ceiling 28 of the vehicle (see Figures 11 to 13). Then, as gas is supplied from the pair of front and rear chambers 34, it inflates and deploys towards the occupant D (rearward) at the rear of the front connecting portion 34B, lagging behind the pair of front and rear chambers 34, and is positioned between the pair of front and rear chambers 34 (front and rear extensions 34A) and in front of the occupant D.

[0057] Furthermore, the airbag body 40 is formed into a bag shape by folding a single base fabric into a predetermined shape and sewing its periphery (see Figure 5(A)). The front and rear chambers 34 are connected by sewing the area around a communication hole (not shown) formed on the rear surface of the left-right center of the base fabric constituting the front connecting portion 34B of the airbag body 40 to the area around a communication hole (not shown) formed on the base fabric of the airbag body 40. The base fabrics of the front and rear chambers 34 and the airbag body 40 are made of, for example, polyamide or polyester fabrics.

[0058] Here, we will explain how the airbag 32 is folded. As shown in Figures 4 and 5(A), the airbag 32 is first unfolded into a flat shape (unfolding step). Next, before the airbag body 40 is folded (rolled up) into a roll shape, the base fabric 40A on both the left and right sides that are inward in the seat width direction are pulled outward in the seat width direction and flattened to a nearly flat state (pulling step). Then, as shown in Figures 4 and 5(B), before the pair of front and rear chambers 34 are folded into an accordion shape, the approximate center of the base fabric 34D in the vertical direction of each is pulled outward in the seat width direction and flattened to a nearly flat state (pulling step).

[0059] In this state, the airbag 32 is folded as shown in Figure 6. First, as shown in Figures 6(A) to 6(C), the airbag body 40 is rolled up from the front to the top. In other words, the airbag body 40 is folded into an outward-rolled shape so that it can be easily unrolled by the inertial force associated with its forward movement. Then, the tip portions 34F of the pair of front and rear chambers 34 (front and rear extension portions 34A) are rolled up once from the front to the top (outward-rolled roll folding: roll folding process).

[0060] Next, as shown in Figures 6(D) to 6(F), the pair of front and rear chambers 34 (front and rear extensions 34A) are folded in an accordion shape, excluding the roll-folded tip portion 34F (accordion folding process). The accordion folding of the pair of front and rear chambers 34 (front and rear extensions 34A), excluding the tip portion 34F, is performed in a way that creates only three peaks. In other words, the accordion folding is performed three times. Figure 6(F) also shows the state in which the branch pipes 46 and 48 of the distribution pipe 50, which will be described later, are connected.

[0061] Thus, the folded state is shown in Figure 7, where the boundary portion 42 (see Figures 7 and 8) between the rolled-up airbag body 40 and the rolled-up front ends 34F of the pair of front and rear chambers 34 forms a fold line, causing the pair of front and rear chambers 34 to be folded downwards.

[0062] Then, as shown in Figure 8, the airbag 32 in this state is stored inside the headrest 18. In other words, the airbag 32 is configured to be positioned along the outer shape (top surface and both left and right sides) of the headrest 18 when viewed from the front, and this stored position is the initial position (mounting position) of the airbag 32.

[0063] Furthermore, a tear line (not shown) is formed on the front of the headrest 18. This tear line is configured to rupture when the airbag 32 inflates and deploys, upon receiving the inflation pressure of the airbag 32. This allows the airbag 32 to inflate and deploy from the front of the headrest 18 towards the front, in the order of a pair of front and rear chambers 34 and the airbag body 40.

[0064] Furthermore, as shown in Figure 9(A), a resin or metal distribution pipe 50 is located at the rear of the headrest 18. The distribution pipe 50 is branched in three directions, and includes cylindrical branch pipes 46 branching to the left and right from the center in the seat width direction, and cylindrical branch pipes 48 branching upward from the center in the seat width direction. In the following, the branch pipe 46 branching 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 branching 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 nozzle 46A of the left branch pipe 46L and the nozzle 46A of the right branch pipe 46R extend forward and upward at a predetermined angle (for example, 20° to 30° with respect to the horizontal) and for a predetermined length when viewed from the side, and the nozzle 48A of the upper branch pipe 48 also extends forward and upward at a predetermined angle (for example, 20° to 30° with respect to the horizontal) and for a predetermined length when viewed from the side.

[0066] The "predetermined length" of nozzles 46A and 48A referred to here is preferably 30mm to 40mm. If the length of nozzles 46A and 48A is shorter than 30mm, the gas may not be ejected in the intended direction, and if it is longer than 40mm, the thickness of the headrest 18 will increase unnecessarily.

[0067] Furthermore, as shown in Figure 10, the nozzles 46A of the left branch pipe 46L and the right branch pipe 46R extend outward and forward 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 outward and forward in the seat width direction, so the roll-shaped airbag body 40 is pulled outward in the seat width direction and moves from the rear to the front.

[0068] Furthermore, as shown in Figures 4, 6(F), and 10, the nozzle 46A of the left branch pipe 46L and the nozzle 46A of the right branch pipe 46R are connected to the left and right base portions 36L and 36R of the rear connecting portion 34C, respectively, and the nozzle 48A of the upper branch pipe 48 is connected to the central base portion 38 of the rear connecting portion 34C. As shown in Figure 9(B), in the airbag 32 housed inside the headrest 18, the left and right base portions 36L and 36R (only the left base portion 36L is shown in Figure 9(B)) are located approximately in the vertical center on the rear side of the pair of front and rear chambers 34.

[0069] In other words, in a side view, the nozzle 46A of the left branch pipe 46L and the nozzle 46A of the right branch pipe 46R (only the left branch pipe 46L is shown in Figure 9(B)) are located approximately in the vertical center on the rear side of the pair of front and rear chambers 34. Also, as shown in Figure 9(A), the inner diameters of the nozzle 46A of the left branch pipe 46L and the nozzle 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 nozzle 48A of the upper branch pipe 48.

[0070] Furthermore, the nozzle 44A of the inflator 44 is connected to a cylindrical base 52 that extends downward from the center of the seat width direction of the distribution pipe 50. 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, which are capable of supplying gas to a pair of front and rear chambers 34, respectively, and is also configured to inject gas into the upper branch pipe 48 of the distribution pipe 50, which is capable of supplying gas to the center of the rear connecting section 34C.

[0071] As shown in Figures 10(B) and 10(C), the rolled-up airbag body 40 is pushed forward by the inflated rear connecting portion 34C. In other words, the airbag body 40 is not only moved forward from its 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. Thus, the rear connecting portion 34C is an extrusion chamber that assists in pushing the airbag body 40 forward, and constitutes an extrusion structure.

[0072] In the airbag device 30 with the above configuration, as shown in Figures 1 to 3, the front-rear extensions 34A of the pair of inflated front-rear chambers 34 extend in the front-rear direction on both the left and right sides of the occupant D's head H, facing the head H from both sides with a gap between them. The front ends of the pair of inflated front-rear extensions 34A are connected in the left-right direction by the inflated front connecting portion 34B. As a result, the front-rear chambers 34, including the pair of front-rear extensions 34A and the front connecting portion 34B protruding from the headrest 18, have a roughly "U" shape that opens rearward in a plan view (see Figure 3).

[0073] Furthermore, as shown in Figures 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 towards the rear (occupant D side) 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 remains folded in a roll shape and passes from the rear to the front through the narrow gap between the occupant D's head H and the ceiling 28 of the vehicle (indicated by dashed lines and arrow A in Figure 11).

[0074] The airbag body 40 is designed to inflate and deploy towards the occupant D (rearward side) with a delay relative to the pair of front and rear chambers 34, at the rear side of the front connecting portion 34B. The inflated airbag body 40 faces the occupant D's head H, chest C, and abdomen B with a gap in the front-rear direction (see Figures 1 to 3). The shape of the inflated airbag body 40 is set so that it is sandwiched between the occupant D's thighs F and chest C from the mid to late stages of occupant restraint.

[0075] Furthermore, as shown in Figures 1 to 3, the airbag 32 is fitted with a pair of rear tethers 54, a pair of front upper tethers 56, and a pair of front lower tethers 58. The rear tethers 54, front upper tethers 56, and front lower tethers 58 are made of, for example, a polyamide or polyester fabric in the shape of a long strip. The fabric that makes up the rear tethers 54, front upper tethers 56, and front lower tethers 58 is made to be less stretchable than the base fabric that makes up the front and rear chambers 34. This resistance to stretching is adjusted by the material and thickness of the fabric.

[0076] The pair of front upper tethers 56 are configured to connect the left and right side walls on the front of the upper part that inflates and deploys upward from the front and rear chambers 34 in the airbag body 40, with the front of the pair of front and rear extending portions 34A. Specifically, one end of each pair of front upper tethers 56 is sewn to the left and right side walls on the front of the upper part that inflates and deploys upward from the front and rear chambers 34 in the airbag body 40. The other end of each pair of front upper tethers 56 is sewn to the front of the pair of front and rear extending portions 34A.

[0077] The pair of front lower tethers 58 are configured to connect the left and right side walls of the front lower part of the airbag body 40 that inflates and deploys below the front and rear chambers 34, with the front part of the pair of front and rear extensions 34A. Specifically, one end of each pair of front lower tethers 58 is sewn to the left and right side walls of the lower part of the airbag body 40 that inflates and deploys below the front and rear chambers 34, respectively. The other end of each pair of front lower tethers 58 is sewn to the front part of the pair of front and rear extensions 34A, respectively.

[0078] On the other hand, one end of each of the pair of rear tethers 54 is sewn to the lower surface of the front part of the front and rear chambers 34 (front and rear extensions 34A) that are facing the approximate center of the inflated and deployed airbag body 40 in the seat width direction when viewed from the side. The other end of each of the pair of rear tethers 54 is attached to the side of the seat back 16 (or the vehicle body behind occupant D, not shown). Therefore, when the airbag 32 is inflated and deployed, the pair of rear tethers 54 extend diagonally downward and rearward below the pair of front and rear extensions 34A.

[0079] In other words, the pair of rear tethers 54 take an inclined position that is tilted diagonally downward and rearward when viewed from the side. As a result, when the occupant D is restrained by the airbag 32, the airbag body 40 is pulled diagonally downward and rearward by the pair of rear tethers 54, and the front part of the airbag body 40 and the pair of front-to-rear extensions 34A are pulled diagonally downward and rearward with the headrest 18 as the pivot point when viewed from the side.

[0080] The folding method for the airbag device 30 and airbag 32 according to the first embodiment, which has the configuration described above, will now be explained in terms of its operation.

[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 of the vehicle seat 12 when viewed from the front. The pair of front and rear chambers 34, which are at both ends in the width direction of the seat, are folded downwards so as to conform to the outer shape of the headrest 18 of the vehicle seat 12. In other words, the airbag 32 is compactly stored inside the headrest 18, and this stored position is the initial position of the airbag 32.

[0082] Furthermore, the headrest 18, which houses the airbag 32, is integrally formed with the seatback 16. Therefore, compared to the case where the headrest 18 is separate from the seatback 16, it is possible to prevent the airbag 32 (airbag device 30) from being detached 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. In other words, gas is generated and ejected from the inflator 44. The gas ejected from the inflator 44 is supplied through the distribution pipe 50 to the pair of front and rear chambers 34 and the rear connecting section 34C of the airbag 32.

[0084] Here, the inflator 44 is positioned as a single unit along the extending direction of the seat back 16 of the vehicle seat 12, and injects gas into a distribution pipe 50 that can supply gas to a pair of front and rear chambers 34 (left and right base sections 36L and 36R) and a rear connecting section 34C (central base section 38), respectively. In other words, gas ejected from the single inflator 44 positioned along the extending direction of the seat back 16 is supplied to the pair of front and rear chambers 34 and the rear connecting section 34C, respectively, by the distribution pipe 50.

[0085] Therefore, compared to the case where the nozzles 44A of the inflator 44 are directly connected to a pair of front and rear chambers 34 (left and right base portions 36L and 36R) and a rear connecting portion 34C (central base portion 38), that is, where three inflators 44 are provided along a direction intersecting the extending direction of the seat back 16 in a side view (projecting diagonally downward and rearward), it is possible to suppress the enlargement (increase in thickness) of the headrest 18 and seat back 16, reduce the number of parts and mounting space, and reduce manufacturing costs.

[0086] When gas is supplied to the pair of front and rear chambers 34, the tear line of the headrest 18 opens due to the expansion pressure of the pair of front and rear chambers 34, and as shown in Figure 11, the pair of front and rear chambers 34 expand and unfold forward from the front of the headrest 18, passing through both sides of the occupant D's head H.

[0087] At this time, the nozzles 46A of the left and right branch pipes 46L and 46R connected to the left and right base portions 36L and 36R of the pair of front and rear chambers 34 extend outward and forward in the sheet width direction at a predetermined angle and length in a plan view. As a result, the pair of front and rear chambers 34 expand and unfold as intended towards the outward and forward in the sheet 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, they are unfolded and unfolded during inflation and deployment. Therefore, even if the position of the occupant D's head H varies in the lateral direction, the inflation and deployment performance of the pair of front and rear chambers 34 of the airbag 32 can be ensured.

[0089] Furthermore, as described above, when gas is supplied to the pair of front and rear chambers 34, gas is also supplied to the rear connecting portion 34C. In other words, the rear connecting portion 34C expands toward the front. As a result, the tear line of the headrest 18 is opened by the expansion pressure of the rear connecting portion 34C via the airbag body 40, that is, the pressing force that pushes the airbag body 40, which is folded into a roll shape by the expanded rear connecting portion 34C, toward the front.

[0090] Then, the airbag body 40, which has been pushed forward by the inflated rear connecting portion 34C, moves forward, passing above the head H of the occupant D, as the pair of front and rear chambers 34 inflate and deploy (see Figure 11). At this time, since the pair of front and rear chambers 34 inflate and deploy outward and forward 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, which is folded into a roll shape, is forcibly pushed forward from its initial position by the rear connecting portion 34C, which is an extrusion chamber, and is pulled outward in the seat width direction by a pair of front and rear chambers 34, while moving forward as the pair of front and rear chambers 34 inflate and deploy. Therefore, in the event of a frontal collision of a vehicle, the time that the airbag body 40 remains in its initial position in a roll shape is shortened.

[0092] Furthermore, when the airbag 32 is folded, it is flattened by the deployment process, and the airbag body 40 has its base fabric 40A on the outside in the seat width direction pulled out in the withdrawal process. Therefore, the thickness of the airbag 32 due to the overlapping of the base fabric can be reduced, and the thickness of the airbag body 40 can be reduced. Therefore, when the airbag body 40 moves forward through the narrow gap between the head H of the occupant D and the ceiling 28 of the vehicle compartment, it is possible to prevent it from getting stuck in that narrow gap, and the occurrence of deployment failures in the airbag 32 can be suppressed or prevented.

[0093] As the pair of front and rear chambers 34 inflate and deploy, and the rolled-up airbag body 40 moves forward, the occupant D's head H is relatively inserted into the gap between the front and rear extended portions 34A of the pair of front and rear chambers 34 and the rolled-up airbag body 40, as shown in Figure 12.

[0094] Then, as shown in Figure 13, gas is supplied from the front connecting portion 34B, which connects the front ends of the front-to-rear extension portions 34A of the pair of front and rear chambers 34 in the left-to-right direction, through a communication hole, causing the airbag body 40 to inflate and deploy toward the occupant D. In other words, the airbag body 40 is positioned between the pair of front and rear chambers 34 and toward the front of the occupant D.

[0095] As described above, the airbag body 40 receives gas from the inflator 44 through the communication hole in the front connecting portion 34B after the pair of front and rear chambers 34 have finished inflating and deploying. In other words, the gas ejected from the inflator 44 and flowing through the pair of front and rear extension portions 34A and the front connecting portion 34B is supplied into the airbag body 40 through the communication hole, so the airbag body 40 inflates and deploys with a delay compared to the pair of front and rear chambers 34.

[0096] Furthermore, the approximate center portion of the base fabric 34D of the pair of front and rear chambers 34 is pulled outward in the sheet width direction by a tensioning process and flattened, and the tip portions 34F of the pair of front and rear chambers 34 are roll-folded once from the front to the top in a roll-folding process. Then, the pair of front and rear chambers 34, excluding the tip portions 34F, are bellows-folded three times in a bellows-folding process.

[0097] Here, it is known that bellows folding deploys faster than roll folding. Therefore, if the pair of front and rear chambers 34 are folded three times in a bellows fashion, the pair of front and rear chambers 34 will inflate and deploy earlier, except for their tip portions 34F, compared to when the number of bellows folds is four or more. Furthermore, the tip portions 34F of the pair of front and rear chambers 34, which are roll-folded only once, can be used to control the airbag body 40 from inflating and deploying until it moves forward through the space between the occupant D's head H and the ceiling 28 of the passenger compartment.

[0098] To explain in more detail, if the number of roll folds at the tip 34F of the pair of front and rear chambers 34 is, for example, 0.5 times, gas begins to flow into the airbag body 40 before it moves forward through the space between the occupant D's head H and the ceiling 28 of the vehicle compartment, making it difficult for the airbag body 40 to move forward through the space between the occupant D's head H and the ceiling 28 of the vehicle compartment. Also, if the number of roll folds is, for example, 1.5 times, the inflow of gas from the tip 34F of the pair of front and rear chambers 34 to the airbag body 40 after it has moved forward is delayed, so the inflation and deployment of the airbag body 40 toward the rear is delayed.

[0099] In contrast, in the first embodiment, since the number of roll folds is only once, gas does not begin to flow into the airbag body 40 before it moves forward through the space between the occupant D's head H and the ceiling 28 of the vehicle compartment, making it easier for the airbag body 40 to move forward through the space between the occupant D's head H and the ceiling 28 of the vehicle compartment. Furthermore, after the airbag body 40 has moved forward, the gas inflow from the tip 34F of the pair of front and rear chambers 34 to the airbag body 40 becomes faster, thus accelerating the rearward inflation and deployment of the airbag body 40.

[0100] In other words, according to the first embodiment, the airbag body 40 can be reliably and quickly passed through (moved) from the rear to the front of the narrow gap between the occupant D's head H and the ceiling 28 of the vehicle compartment, while remaining folded in a roll shape, as the pair of front and rear chambers 34 inflate and deploy. After passing through, it can be quickly inflated and deployed towards the occupant D, thereby improving its deployment performance. Therefore, it is possible to expedite the completion of inflation and deployment of the airbag body 40, which is initially mounted in a roll-shaped folded state.

[0101] Furthermore, in this first embodiment, the inner diameter of the nozzles 46A of the left and right branch pipes 46L and 46R connected to the respective base portions 36L and 36R of the pair of front and rear chambers 34 is larger than the inner diameter of the nozzle 48A of the branch pipe 48 connected to the base portion 38 of the rear connecting portion 34C. As a result, the amount of gas supplied to the pair of front and rear chambers 34 can be increased compared to the amount of gas supplied to the rear connecting portion 34C, which also helps to expedite the inflation and deployment of the airbag body 40.

[0102] Thus, according to the first embodiment, by inflating and deploying through the space between the occupant D's head H and the ceiling 28 of the vehicle compartment, it is possible to achieve both improved deployment performance of the airbag body 40, which is positioned in front of the occupant D, and an earlier completion of inflation and deployment. In particular, since the extrusion structure that assists in pushing out the airbag body 40 is composed of a rear connecting portion 34C as an extrusion chamber that connects a pair of front and rear chambers 34 to each other, the airbag body 40, which is folded in a roll shape, can be reliably pushed forward from its initial position by the rear connecting portion 34C.

[0103] Furthermore, when the airbag body 40 inflates and deploys, a pair of front upper tethers 56 connect the left and right sides of the front upper part of the airbag body 40 to the front part of a pair of front-to-rear extending portions 34A, respectively. This pair of front upper tethers 56 prevents the airbag body 40 (airbag 32) from being unintentionally displaced (rotated) upward around the front connecting portion 34B relative to the front-to-rear chambers 34 when the inflation and deployment of the airbag body 40 is complete.

[0104] Furthermore, when the airbag body 40 inflates and deploys, a pair of front lower tethers 58 connect the left and right sides of the front lower part of the airbag body 40 to the front part of a pair of front-to-rear extensions 34A, respectively. This pair of front lower tethers 58 prevents the airbag body 40 (airbag 32) from unintentionally displacing (rotating) downward around the front connecting portion 34B relative to the front-to-rear chambers 34 when the inflation and deployment of the airbag body 40 is complete.

[0105] Furthermore, when the airbag 32 has finished inflating and deploying, the pair of rear tethers 54 extend diagonally downward and rearward below the pair of front-to-rear extensions 34A. In other words, the pair of rear tethers 54 restrict the diagonal upward and forward movement of the airbag body 40. This suppresses the vertical and front-to-back oscillation of the airbag 32 (contributing to the stabilization of the deployment behavior of the airbag body 40).

[0106] In this state, occupant D, who has moved forward due to inertia caused by the impact of a frontal collision, is restrained by the airbag body 40. Specifically, when occupant D is restrained, the front and rear chambers 34 (front and rear extension portion 34A) are extended forward due to the forward movement of occupant D. Then, the airbag body 40 is compressed and deformed forward as it is pressed forward by occupant D.

[0107] Therefore, the energy absorption performance of the airbag body 40 can be improved, and its 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 tensile load, the load applied to the occupant D from the airbag body 40 increases, but the compressive deformation of the airbag body 40 can reduce the load applied to the occupant D.

[0108] Furthermore, the airbag unit 40 is shaped to be sandwiched between the thighs F and chest C of occupant D during the mid to late stages of occupant restraint by the airbag 32, allowing it to make contact with a wide area of ​​occupant D's upper body. This effectively reduces the load applied to occupant D from the airbag unit 40.

[0109] Furthermore, since the airbag body 40 inflates and deploys toward the occupant D at the rear side of the front connecting portion 34B after the front and rear chambers 34 have 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 earlier, improving the initial restraint performance of the occupant D by the airbag body 40.

[0110] Furthermore, since the pair of rear tethers 54 are less likely to stretch than the front and rear chambers 34, when occupant D is restrained, the airbag body 40 is relatively pulled diagonally downward and rearward by the pair of rear tethers 54. This stabilizes the vertical position of the airbag body 40 relative to occupant D's head H when occupant is restrained. In other words, this airbag 32 allows occupant D to be properly restrained.

[0111] <Second Embodiment> Next, the airbag device 30 according to the second embodiment will be described. Note that parts equivalent to those in the first embodiment are denoted by the same reference numerals, and detailed descriptions (including common functions) will be omitted as appropriate.

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

[0113] Therefore, the same effects and advantages as in the first embodiment are obtained, and the airbag body 40, which is folded into a roll shape, is reliably pushed forward from its initial position (mounting position) by its extrusion chamber 35. Furthermore, in this second embodiment, since the extrusion chamber 35 is constructed separately from the pair of front and rear chambers 34, the configuration of the airbag 32 can be simplified. In other words, this extrusion chamber 35 also constitutes the airbag 32.

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

[0115] As shown in Figure 15, this third embodiment differs from the first and second embodiments in that it has two inflators 44: a first inflator 44B that supplies gas to a pair of front and rear chambers 34, and a second inflator 44C that supplies gas to the rear connecting section 34C (or the extrusion chamber 35 shown in Figure 14). The vehicle seat 12 is also 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 section 34C (or the extrusion chamber 35).

[0116] The first distribution pipe 51 is formed in a roughly "T" shape when viewed from the front, and has a cylindrical branch pipe 51L that branches off to the left from the center in the sheet width direction, and a cylindrical branch pipe 51R that branches off to the right from the center in the sheet width direction. The nozzles 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 nozzle of the inflator 44B is connected to the cylindrical base of the first distribution pipe 51 that extends downward from the center in the sheet width direction.

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

[0118] Furthermore, the inner diameters of the left and right branch pipes 51L and 51R outlets 51A in the first distribution pipe 51 are larger than the inner diameter of the outlet 53A of the second distribution pipe 53. As a result, similar to the first or second embodiment described above, the amount of gas supplied to the pair of front and rear chambers 34 can be increased to be greater than the amount of gas supplied to the rear connecting section 34C (or extrusion chamber 35), thereby accelerating the completion of inflation and deployment of the airbag body 40.

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

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

[0121] As shown in Figure 16, this fourth embodiment differs from the first and second embodiments in that the extrusion structure 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 which connects (interconnects) the rear ends of the pair of front and rear chambers 34 (front and rear extending portions 34A) in the left-right direction, or an extrusion chamber 35 which is separate from the pair of front and rear chambers 34.

[0122] The extruded fabric 26 is formed in a rectangular shape with the sheet width direction as the longitudinal direction when viewed from the rear, and is formed to be approximately the same size as the rear connecting portion 34C. Furthermore, this extruded fabric 26 is made of, for example, a polyamide or polyester fabric, and both ends in the sheet width direction are sewn and attached to predetermined positions on the rear side of the base fabric 34D (see Figure 5(B)) on the inside of the sheet width direction of the pair of front and rear chambers 34 (front and rear extension portions 34A).

[0123] Therefore, when the pair of front and rear chambers 34 inflate and deploy forward (more specifically, outward and forward in the seat width direction), a predetermined tension is applied to the extruded fabric 26 in the seat width direction. Consequently, the rolled airbag body 40 is reliably pushed forward from its initial position (mounting position) by the extruded fabric 26. Furthermore, in this fourth embodiment, since the extrusion structure is composed of the extruded fabric 26, it can be stored compactly and the airbag 32 can be made lighter.

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

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

[0126] As shown in Figure 17, this fifth embodiment differs from the first and second embodiments in that three inflators 44 are provided, each capable of supplying gas to a pair of front and rear chambers 34 and a rear connecting section 34C (or the extrusion chamber 35 shown in Figure 14). Specifically, the nozzles of the inflators 44L and 44R are directly connected to the respective base sections 36L and 36R of the pair of front and rear chambers 34, and the nozzle of the inflator 44D is directly connected to the base section 38 of the rear connecting section 34C (or the extrusion chamber 35).

[0127] Therefore, in this fifth embodiment, a distribution pipe 50 is not required, but the three inflators 44L, 44R, and 44D are configured to protrude in a direction that intersects with the extending direction of the seat back 16 (downward rearward) when viewed from the side (not shown). In addition, in this fifth embodiment, the output of the two inflators 44L and 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 section 34C (or extrusion chamber 35).

[0128] Therefore, in this fifth embodiment, the headrest 18 and seat back 16 are enlarged (thickened), but as with the first to third embodiments, the amount of gas supplied to the pair of front and rear chambers 34 can be increased compared to the amount of gas supplied to the rear connecting portion 34C (or extrusion chamber 35), thereby accelerating the inflation and deployment of the airbag body 40.

[0129] <Sixth Embodiment> Next, an airbag device 30 according to the sixth embodiment will be described. Note that parts equivalent to those in the first embodiment are denoted by the same reference numerals, and detailed descriptions (including common functions) will be omitted as appropriate.

[0130] As shown in Figure 18, this sixth embodiment differs from the first embodiment in that, instead of rolling the front and rear chambers 34F once, a valve mechanism 60 is provided at the front and rear chambers 34F to momentarily block the inflow of gas. This valve mechanism 60 has a cylindrical valve body 62 whose inner diameter gradually decreases, and the valve body 62 is made of a polyamide or polyester fabric, similar to the base fabric of the airbag 32.

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

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

[0133] Then, as more gas flows in in the direction of arrow E, as shown in Figure 19(C), the smallest inner diameter portion 62B of the valve body 62 reverses direction, passing over the largest inner diameter portion 62A from the inside and positioning itself downstream in the direction of gas inflow. This opens the inside of each front and rear chamber 34, and gas is supplied from the front end 34F of each front and rear chamber 34 to the rolled-up airbag body 40.

[0134] Thus, according to the sixth embodiment, since a valve mechanism 60 that instantaneously prevents gas from flowing in is provided at the tip 34F of the pair of front and rear chambers 34, it is possible to control the flow of gas to the airbag body 40 until it moves forward through the space between the occupant D's head H and the ceiling 28 of the vehicle compartment. Therefore, the airbag body 40 can move forward reliably and quickly, and as a result, the inflation and deployment of the airbag body 40 can be expedited.

[0135] <Seventh Embodiment> Finally, the airbag device 30 according to the seventh embodiment will be described. Note that parts equivalent to those in the first embodiment are denoted by the same reference numerals, and detailed descriptions (including common functions) will be omitted as appropriate.

[0136] As shown in Figures 20 and 21(A), this seventh embodiment differs from the first embodiment in that, instead of rolling the front and rear chambers 34F once, a valve mechanism 60 is provided at the front and rear chambers 34F to momentarily block the inflow of gas.

[0137] This valve mechanism 60 consists 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 edges when the upper and lower peripheral edges of two long base fabrics are sewn together to form the front and rear chambers 34. This temporary fastening member 64 is also made of a fabric material such as polyamide or polyester, similar to the base fabric of the airbag 32.

[0138] With this temporary fixing member 64, at the tip portion 34F of each flattened front and rear chamber 34, a portion upstream of the temporary fixing member 64 in the gas inflow direction is inserted between the temporary fixing member 64 and the base fabric 34D facing the temporary fixing member 64 in the sheet width direction, thereby instantaneously closing the inside of each front and rear chamber 34 as shown in Figure 21(A).

[0139] Then, as more gas flows in in the direction of arrow E, a portion of each front and rear chamber 34, which was inserted between the temporary fixing member 64 and the base fabric 34D, detaches from that space, and the inside of each front and rear chamber 34 is opened, as shown in Figure 21(B). In other words, gas is supplied from the tip 34F of each front and rear chamber 34 to the rolled-up airbag body 40.

[0140] Thus, according to the seventh embodiment, since a valve mechanism 60 that instantaneously prevents gas from flowing in is provided at the tip 34F of the pair of front and rear chambers 34, it is possible to control the flow of gas to the airbag body 40 until it moves forward through the space between the occupant D's head H and the ceiling 28 of the vehicle compartment. Therefore, the airbag body 40 can move forward reliably and quickly, and as a result, the inflation and deployment of the airbag body 40 can be expedited.

[0141] The folding method of the seat-mounted airbag device 30 and airbag 32 according to this embodiment has been described above with reference to the drawings. However, the folding method of the seat-mounted airbag device 30 and airbag 32 according to this embodiment is not limited to that shown in the drawings, and can be modified as appropriate without departing from the spirit 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 on a cardboard base (not shown) on which reference lines for folding are marked. Also, 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 speeds up the inflation and deployment of the airbag body 40. In addition, in vehicles where there is a relatively wide gap between the occupant D's head H and the ceiling 28 of the passenger compartment, the airbag body 40 may be folded into a roll shape that is inward, opposite to that of the above embodiment.

[0143] However, it is preferable that the roll fold of the tip portions 34F of the pair of front and rear chambers 34 be an outward roll fold. This allows the airbag body 40, when folded into a roll shape, to hit the rear upper end of the occupant D's head H as it moves forward as the pair of front and rear chambers 34 inflate and deploy, to continue moving forward by rolling along the rear upper end of the occupant D's head H while remaining in that state.

[0144] Furthermore, the distribution pipes 50, 51, and 53 may be provided spanning between the inside of the headrest 18 and the inside of the seat back 16. Also, for example, in the first embodiment, the base portions 36 and 38 are shown to be inserted into the inside of the nozzles 46A and 48A, but the invention is not limited to this, and may be configured to be fitted over the outside of the nozzles 46A and 48A. [Explanation of symbols]

[0145] 12 Vehicle seats 16 Seatback 18 Headrests 26. Extruded fabric (extruded structure) 28 Ceiling 30 Airbag system 32 airbags 34 Front and rear chambers 34C Rear connecting section (extrusion chamber / extrusion structure) 35. Extrusion Chamber (Extrusion Structure) 40 Airbag Unit 44 Inflators 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 installed in the vehicle seat that releases gas in the event of a vehicle collision, An airbag comprising: a pair of front and rear chambers that, when supplied with gas ejected from the inflator, inflate and deploy toward the front of the seat, passing on both sides of the head of an occupant seated in the vehicle seat; and an airbag body that, as the pair of front and rear chambers inflate and deploy, moves toward the front of the seat, passing between the occupant's head and the ceiling of the vehicle compartment, and, as the gas is supplied from the pair of front and rear chambers, inflates and deploys toward the rear of the seat between the pair of front and rear chambers, and is positioned toward the front of the occupant's seat; Equipped with, The aforementioned airbag, A seat-mounted airbag device having an extrusion structure on the rear side of the airbag body that pushes the airbag body forward towards the seat.

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

3. The seat-mounted airbag device according to claim 1, wherein the extrusion structure is comprised of an extrusion chamber separate from the pair of front and rear chambers.

4. The seat-mounted airbag device according to claim 1, wherein the extrusion structure is composed of an extruded fabric that connects the pair of front and rear chambers to each other.

5. The inflator is provided as a single unit, and the vehicle seat is provided with distribution pipes capable of supplying the gas ejected from the inflator to the pair of front and rear chambers and the extrusion chamber, respectively. The seat-mounted airbag device according to claim 2 or 3, wherein the inner diameter of the nozzle of the distribution pipe connected to the base of the pair of front and rear chambers is larger than the inner diameter of the nozzle of the distribution pipe connected to the base of the extrusion chamber.

6. The headrest of the aforementioned vehicle seat is formed integrally with the seat back of the aforementioned vehicle seat. The seat-mounted airbag device according to claim 5, wherein the inflator is arranged along the 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. The vehicle seat is provided with a first distribution pipe capable of supplying gas ejected from the first inflator to the pair of front and rear chambers, and a second distribution pipe capable of supplying gas ejected from the second inflator to the extrusion chamber. The seat-mounted airbag device according to claim 2 or 3, wherein the inner diameter of the nozzle of the first distribution pipe connected to the base of the pair of front and rear chambers is larger than the inner diameter of the nozzle of the second distribution pipe connected to the base of the extrusion chamber.

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

9. Three inflators are provided, each capable of supplying gas to the pair of front and rear chambers and the extrusion chamber, respectively. The seat-mounted airbag device according to claim 2 or 3, wherein the output of the two inflators that supply gas to the pair of front and rear chambers is higher than the output of the one inflator that supplies gas to the extrusion chamber.

10. The seat-mounted airbag device according to any one of claims 1 to 4, wherein a valve mechanism for instantaneously blocking the inflow of the gas is provided at the tip of the pair of front and rear chambers.

11. A method for folding an airbag comprising: a pair of front and rear chambers that, when gas is supplied from an inflator provided in the vehicle seat during a vehicle collision, inflate and deploy toward the front of the seat, passing on both sides of the head of an occupant seated in the vehicle seat; and an airbag body that, as the pair of front and rear chambers inflate and deploy, moves toward the front of the seat, passing between the occupant's head and the ceiling of the vehicle compartment, and is inflated and deployed toward the rear of the seat between the pair of front and rear chambers, and is positioned toward the front of the occupant's seat, wherein the airbag body is positioned toward the front of the occupant's seat. The process of deploying the airbag to make it flat, A pulling step in which the base fabric on the outer side of the airbag body in the seat width direction is pulled outwards in the seat width direction, An airbag folding method having [a specific feature / feature].

12. A roll folding step in which the front and rear ends of the pair of front and rear chambers are roll-folded a predetermined number of times from the front side of the sheet towards the top side of the sheet, A bellows folding step in which the pair of front and rear chambers, excluding the tip portion, are folded multiple times in a bellows-like manner, The airbag folding method according to claim 11, having the following:

13. The airbag folding method according to claim 12, wherein the number of roll folding steps in the roll folding step is one.

14. The airbag folding method according to claim 12 or claim 13, wherein the number of bellows folds in the bellows folding step is three.

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