Seat-mounted airbag system

Abstract

To provide a seat-mounted airbag device capable of compactly storing an airbag comprising an airbag body which is inflated and deployed through between a head of an occupant and a ceiling of a cabin, and which is thereby disposed at a seat front side of the occupant, without impeding deployment performance of the airbag.SOLUTION: A seat-mounted airbag device 30 comprises: an inflator for jetting gas upon collision of a vehicle; and an airbag 32 comprising an airbag body 40 which, when the gas jetted from the inflator is supplied, moves toward a seat front side through between a head H of an occupant D seated in a vehicle seat 12 and a ceiling of a cabin, and is inflated and deployed, and which is disposed at the seat front side of the occupant D. The airbag 32 is stored in a headrest 18 while both seat width direction end parts are bent toward a seat lower side so as to follow an outer shape of the headrest 18 of the vehicle seat 12 in a front view seen from the seat front side.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a seat-attached airbag device.

Background Art

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

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

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 system described above, the airbag (bag) inflates and deploys from the seatback through the gap between the occupant's head and the ceiling, positioning itself in front of the occupant. However, if the airbag is to be laid flat and then rolled up and mounted on the seatback to avoid hindering its deployment performance, the dimensions of the airbag in the seat width direction become equal to the dimensions of the seatback in the seat width direction. Furthermore, if such an airbag is mounted near the headrest, the surrounding dimensions become larger, reducing the occupant's rearward visibility.

[0006] Therefore, the present invention aims to provide a seat-mounted airbag device that allows for compact storage of an airbag without hindering the deployment performance of the airbag, which has an 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 compartment. [Means for solving the problem]

[0007] 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 inflator that ejects gas in the event of a vehicle collision, and an airbag having an airbag body that, when supplied with gas ejected from the inflator, moves forward through the space between the head of an occupant seated on the vehicle seat and the ceiling of the vehicle compartment, inflates and deploys, and is positioned in front of the occupant's seat, wherein, in a front view from the front of the seat, both ends in the width direction of the seat are folded downward on the seat so as to conform to the outer shape of the headrest of the vehicle seat, and the airbag is stored in the headrest.

[0008] According to the first embodiment of the invention, when a vehicle collision occurs, gas ejected from the inflator is supplied, causing the airbag body to move forward through the space between the head of the occupant seated in the vehicle seat and the ceiling of the vehicle compartment, inflate and deploy, and be positioned in front of the occupant's seat. The term "at the time of collision" here also includes when the inevitability of a collision is predicted (foreseen).

[0009] Here, the airbag body is compactly stored in the headrest, with both ends in the seat width direction folded downwards to conform to the outer shape of the vehicle seat's headrest when viewed from the front of the seat. However, when the airbag is inflated and deployed, both ends in the seat width direction are pulled outwards in the seat width direction. Therefore, even though both ends of the airbag in the seat width direction are folded downwards and stored, they are unfolded as they inflate and deploy.

[0010] In other words, according to the present invention, even an airbag having an 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 compartment can be compactly stored in the headrest without its deployment performance being hindered. This also suppresses the increase in the size of the headrest when viewed from the front and side.

[0011] Furthermore, a second embodiment of the present invention is a seat-mounted airbag device of the first embodiment, wherein both ends of the airbag in the seat width direction are a pair of front and rear chambers that inflate and deploy toward the front of the seat by passing on both sides of the occupant's head as gas is supplied from the inflator, and the airbag body 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, and as gas is supplied from the pair of front and rear chambers, it 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.

[0012] According to the second embodiment of the invention, both ends of the airbag in the seat width direction are a pair of front and rear chambers that inflate and deploy toward the front of the seat, passing on both sides of the occupant's head as gas is supplied from an inflator. The airbag body then moves toward the front of the seat, passing between the occupant's head and the ceiling of the vehicle, as the pair of front and rear chambers inflate and deploy. As gas is supplied from the pair of front and rear chambers, the airbag body 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 seat in front of the occupant. In other words, the airbag body inflates and deploys toward the occupant with a delay compared to the pair of front and rear chambers. Therefore, when an occupant is restrained, the airbag body can compress and deform toward the front of the seat while extending the front and rear chambers, thereby effectively ensuring its occupant restraint performance.

[0013] Furthermore, a third embodiment of the seat-mounted airbag device according to the present invention is a seat-mounted airbag device according to the second embodiment, wherein the pair of front and rear chambers are bent downwards from the boundary with the airbag body.

[0014] According to the third embodiment of the invention, the pair of front and rear chambers are bent downwards from the boundary with the airbag body. Here, the boundary is the least rigid. Therefore, the pair of front and rear chambers are easily bent downwards from the seat, making it easier to install the airbag onto the headrest.

[0015] Furthermore, a fourth embodiment of the seat-mounted airbag device according to the present invention is a seat-mounted airbag device according to the third embodiment, wherein the headrest is formed integrally with the seat back of the vehicle seat.

[0016] According to the fourth 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 being detached from the vehicle seat.

[0017] Furthermore, a fifth embodiment of the seat-mounted airbag device according to the present invention is a seat-mounted airbag device according to the fourth embodiment, wherein the left and right airbag doors formed by the headrest rupturing when the pair of front and rear chambers are inflated and deployed are configured to roll back toward the occupant's head.

[0018] According to the fifth embodiment of the invention, when the pair of front and rear chambers inflate and deploy, the left and right airbag doors formed by the opening of the headrests roll back toward the occupant's head. Therefore, it becomes possible to move the occupant's head toward the center in the seat width direction by the airbag doors, preventing the occupant's head from obstructing the inflation and deployment of the pair of front and rear chambers.

[0019] Furthermore, a seat-mounted airbag device according to a sixth aspect of the present invention is a seat-mounted airbag device according to a fourth or fifth aspect, wherein the inflator is arranged as a single unit along the extending direction of the seat back of the vehicle seat and is configured to inject the gas into the interior of a distribution pipe capable of supplying the gas to a pair of front and rear chambers, respectively.

[0020] According to the sixth embodiment of the invention, the inflator is arranged as a single unit along the extending direction of the seat back of the vehicle seat and ejects gas into a distribution pipe capable of supplying gas to a pair of front and rear chambers, respectively. Therefore, compared to the case where two inflators are provided in a direction intersecting the extending direction of the seat back in a side view, so as to be able to directly supply gas to a pair of front and rear chambers, the enlargement (increase in thickness) of the seat back is suppressed, and manufacturing costs can be reduced.

[0021] Furthermore, the seventh embodiment of the present invention is the seat-mounted airbag device of the sixth embodiment, wherein the nozzle of the distribution pipe to which the base portions of the pair of front and rear chambers are connected extends outward and forward in the seat width direction for a predetermined length in a plan view.

[0022] According to the invention of the seventh aspect, the ejection port of the distribution pipe to which the base portions of the pair of front and rear chambers are connected extends by a predetermined length forward and outward in the seat width direction in a plan view. Therefore, even if the position of the occupant's head varies in the left-right direction, the inflation and deployment performance of the airbag (the pair of front and rear chambers) is ensured.

Effect of the Invention

[0023] As described above, according to the present invention, the airbag can be compactly stored without inhibiting the deployment performance of the airbag having an airbag body disposed on the front side of the seat of the occupant by inflating and deploying through the space between the occupant's head and the ceiling of the vehicle compartment.

Brief Description of the Drawings

[0024] [Figure 1] It is a schematic perspective view showing a state where the airbag of the seat-mounted airbag device according to the present embodiment is inflated and deployed. [Figure 2] It is a schematic side view showing a state where the airbag of the seat-mounted airbag device according to the present embodiment is inflated and deployed. [Figure 3] It is a schematic plan view showing a state where the airbag of the seat-mounted airbag device according to the present embodiment is inflated and deployed. [Figure 4] It is a schematic plan view showing the shape of the airbag before folding in the present embodiment. [Figure 5] (A) to (F) are schematic plan views showing the folding process of the airbag in the present embodiment. [Figure 6] It is a schematic plan view showing the shape of the airbag after folding in the present embodiment. [Figure 7] It is a schematic front view showing a part of the cross section of the airbag stored in the headrest in the present embodiment. [Figure 8] It is a schematic front view showing the shape of the distribution pipe in the present embodiment with a part of the cross section and omitting the airbag. [Figure 9] It is a schematic side view showing a part of the cross section of the airbag stored in the headrest in the present embodiment. [Figure 10] This is a schematic plan view showing a partial cross-section of the airbag housed in the headrest in this embodiment. [Figure 11] This is a schematic plan view showing the state in which the airbag in this embodiment is in the process of inflating and deploying from the headrest. [Figure 12] This is a schematic side view showing the initial stage of airbag inflation and deployment in this embodiment. [Figure 13] This is a schematic side view showing the airbag in the mid-stage of inflation and deployment in this embodiment. [Figure 14] This is a schematic side view showing the airbag in the later stages of inflation and deployment in this embodiment. [Modes for carrying out the invention]

[0025] 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.

[0026] As shown in Figure 1, the occupant protection device 10 consists of a vehicle seat 12 and a seat-mounted airbag device (hereinafter simply referred to as "airbag device") 30 according to this embodiment. 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 12 to 14).

[0027] 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".

[0028] 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 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 Figures 9 and 10).

[0029] 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.

[0030] The airbag system 30 comprises an airbag 32 and a single inflator 44 (see Figures 8 and 9). The airbag 32 is normally stored inside the headrest 18 in a folded state (see Figures 7, 9, and 10). 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.

[0031] 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.

[0032] 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 Figures 8 and 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.

[0033] 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.

[0034] 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 the rear ends of the pair of front and rear extending sections 34A in the left-right direction.

[0035] 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.

[0036] 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.

[0037] 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 12 to 14). 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.

[0038] 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. 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.

[0039] Furthermore, as shown in Figure 4, before the airbag body 40 is folded (rolled) into a roll shape, the base fabrics 40A on both the left and right sides, which are positioned inward in the seat width direction, are pulled outward in the seat width direction and flattened to a nearly flat state. Also, as shown in Figure 4, before the pair of front and rear chambers 34 are folded into an accordion shape, the approximately central part 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.

[0040] In this state, the airbag 32 is folded, as shown in Figure 5. Specifically, first, as shown in Figures 5(A) to 5(C), the airbag body 40 is rolled up from the front. 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.

[0041] Next, as shown in Figures 5(D) to 5(F), the pair of front and rear chambers 34 (front and rear extensions 34A) are folded in an accordion-like manner. Note that the accordion folding of the pair of front and rear chambers 34 (front and rear extensions 34A) is such that only three peaks are formed. Figure 5(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.

[0042] As shown in Figure 6, the folded state is represented by a boundary 42 between the roll-shaped folded airbag body 40 and the bellows-shaped folded pair of front and rear chambers 34, where the pair of front and rear chambers 34 are folded downwards. The airbag 32, with the bellows-shaped folded pair of front and rear chambers 34 folded downwards relative to the roll-shaped folded airbag body 40, is then stored inside the headrest 18, as shown in Figure 7.

[0043] 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. 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.

[0044] Furthermore, as shown in Figure 8, 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."

[0045] As shown in Figure 9, 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 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 a predetermined length when viewed from the side.

[0046] 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.

[0047] 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, as shown in Figure 11, 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.

[0048] As shown in Figures 4 and 5(F), 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, 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) are located approximately in the vertical center on the rear side of the pair of front and rear chambers 34.

[0049] 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) 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 8, 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.

[0050] 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.

[0051] Furthermore, as shown in Figure 10, when the pair of front and rear chambers 34 of the airbag 32 inflate and deploy, the tear lines (not shown) formed on the front of the headrest 18 rupture due to the inflation pressure of the pair of front and rear chambers 34. As a result, a portion of both the left and right sides of the front of the headrest 18 curls towards the occupant D's head H (inward in the seat width direction), and these curled portions become the left and right airbag doors 24. In other words, a portion of the pad 18A made of urethane foam or the like that makes up the headrest 18, and a portion of the surface material 18B that overlaps the pad 18A, constitute the airbag doors 24.

[0052] Furthermore, as shown in Figure 9, when the airbag body 40 of the airbag 32 ruptures the tear line (not shown) formed on the front of the headrest 18, a portion of the upper front of the headrest 18 is configured to curl downwards towards the head H of the occupant D, and this curled portion becomes the airbag door 24.

[0053] 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).

[0054] Furthermore, 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, as shown in Figure 11, 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 (see also Figures 12 to 14).

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] The operation of the airbag device 30 according to this embodiment, which has the configuration described above, will now be explained.

[0062] 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 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.

[0063] The pair of front and rear chambers 34 are folded downward from the boundary 42 with the airbag body 40. Here, the boundary 42 is the part with the least rigidity in the folded airbag 32. Therefore, the pair of front and rear chambers 34 are easily folded downward from the boundary 42, and the work of installing the airbag 32 in that state inside the headrest 18 is made easier.

[0064] 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.

[0065] 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.

[0066] 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 the interior of 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.

[0067] Therefore, compared to the case where the nozzles 44A of the inflators 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 in a side view along a direction intersecting the extending direction of the seat back 16 (projecting diagonally downward and rearward), it is possible to suppress the enlargement (increase in thickness) of the headrest 18 and seat back 16, and to reduce manufacturing costs.

[0068] 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 12, the pair of front and rear chambers 34 expand and unfold forward from the front of the headrest 18, passing on both sides of the occupant D's head H.

[0069] At this time, the nozzles 46A of the left and right branch pipes 46L and 46R to which the left and right base portions 36L and 36R of the pair of front and rear chambers 34 are connected extend outward and forward in the sheet width direction at a predetermined angle and length in a plan view. Therefore, the pair of front and rear chambers 34 expand and unfold as intended towards the outward and forward in the sheet width direction.

[0070] 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.

[0071] Furthermore, when the pair of front and rear chambers inflate and deploy, the left and right airbag doors 24, formed by the rupture of a portion of the headrest 18, curl towards the occupant D's head H (inward in the seat width direction). Therefore, the left and right airbag doors 24 can move the occupant D's head H toward the center in the seat width direction, and the occupant D's head H can also prevent the inflation and deployment of the pair of front and rear chambers 34 from being obstructed.

[0072] Furthermore, when gas is supplied to the rear connecting portion 34C, the tear line of the headrest 18 is opened by the inflation 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 in a rolled-up state, toward the front.

[0073] 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. 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.

[0074] Furthermore, as will be described later, after the inflation and deployment of the pair of front and rear chambers 34 is complete, gas from the inflator 44 is supplied to the airbag body 40 through the communication hole in the front connecting portion 34B. 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. Therefore, the airbag body 40 can be inflated and deployed with a sufficient delay compared to the pair of front and rear chambers 34.

[0075] As a result, the airbag body 40, while remaining folded in a roll shape, can reliably and easily pass through the narrow gap between the occupant D's head H and the ceiling 28 of the vehicle compartment from rear to front as the pair of front and rear chambers 34 inflate and deploy. Therefore, it is possible to prevent the airbag body 40 from getting stuck in the narrow gap, and to suppress or prevent the occurrence of deployment failures in the airbag 32.

[0076] Thus, the airbag 32 according to this embodiment has an airbag body 40 that is positioned in front of occupant D by inflating and deploying through the narrow gap between occupant D's head H and the ceiling 28 of the vehicle compartment. The airbag 32 can be compactly stored inside the headrest 18 without its deployment performance being hindered. Therefore, the enlargement of the headrest 18 in front and side views can be suppressed, and the reduction in rearward visibility for occupant D can also be suppressed.

[0077] 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 13.

[0078] Then, as shown in Figure 14, 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.

[0079] 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.

[0080] 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.

[0081] 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).

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] The seat-mounted airbag device 30 according to this embodiment has been described above based on the drawings. However, the seat-mounted airbag device 30 according to this embodiment is not limited to the illustrated version, and can be modified as appropriate without departing from the spirit of the present invention. For example, the shape of the airbag 32 is not limited to the illustrated version.

[0088] Furthermore, the distribution pipe 50 may be provided spanning between the inside of the headrest 18 and the inside of the seat back 16. Also, although the base portions 36 and 38 shown in the figure are inserted into the inside of each nozzle 46A and 48A, the configuration is not limited to this, and they may be fitted over the outside of each nozzle 46A and 48A. [Explanation of symbols]

[0089] 12 Vehicle seats 16 Seatback 18 Headrests 24 Airbag Door 28 Ceiling 30 Airbag system 32 airbags 34 Front and rear chambers 36. Root area 40 Airbag Unit 42 Boundary 44 Inflators 46A spout 50 minutes plumbing 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 from the front of the headrest of the vehicle seat, passing on both sides of the head of the occupant seated in the vehicle seat towards the front of the seat; and an airbag body that, while folded, moves from the rear of the seat to the front of the seat, passing between the occupant's head and the ceiling of the vehicle compartment as the pair of front and rear chambers inflate and deploy, and then, when supplied with gas from the pair of front and rear chambers, inflates and deploys between the pair of front and rear chambers toward the rear of the seat with a delay relative to 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 in which, when viewed from the front of the seat, the pair of front and rear chambers are folded downwards towards the seat and stored in the headrest, relative to the folded airbag body so as to follow the upper surface and left and right sides of the outer shape of the headrest.

2. The seat-mounted airbag device according to claim 1, wherein the inflated and deployed airbag body is configured to face the occupant's head, chest, and abdomen with a gap in the front-to-rear direction of the seat.

3. The seat-mounted airbag device according to claim 1, wherein the pair of front and rear chambers are bent downward from the boundary with the airbag body toward the seat.

4. The seat-mounted airbag device according to claim 3, wherein the headrest is formed integrally with the seat back of the vehicle seat.

5. The seat-mounted airbag device according to claim 4, wherein the left and right airbag doors, formed by the headrest splitting open when the pair of front and rear chambers inflate and deploy, are configured to roll back toward the occupant's head.

6. The aforementioned inflator is The seat-mounted airbag device according to claim 4 or 5, which is arranged in a single unit along the extending direction of the seat back of the vehicle seat and configured to inject the gas into the interior of a distribution pipe capable of supplying the gas to the pair of front and rear chambers, respectively.

7. The seat-mounted airbag device according to claim 6, wherein the nozzle of the distribution pipe to which the base portions of the pair of front and rear chambers are connected extends for a predetermined length outward and forward in the seat width direction when viewed in plan.

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