Seat-mounted airbag system

Abstract

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

Description

Technical Field

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

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 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 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 (for example, see Patent Document 2). In this bag body, in the deployed state, a escape part that penetrates in the vertical direction between the pair of head support parts 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 device as described above, the airbag (bag body) is disposed on the front side of the occupant by expanding and deploying while passing through the gap between the occupant's head and the ceiling from the seat back. However, if there are variations in the folding method of the airbag, the airbag that attempts to expand and deploy may swing in the vertical or horizontal direction, and its deployment behavior may not be stable.

[0006] Therefore, the present invention aims to provide a seat-mounted airbag device that stabilizes the deployment behavior of the airbag body, which is 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 first embodiment of the present invention provides a seat-mounted airbag device that is provided on a vehicle seat and ejects gas in the event of a vehicle collision; a pair of front and rear chambers that are supplied with gas ejected from the inflator and inflate and deploy toward the front of the seat, passing on both 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, as the pair of front and rear chambers inflate and deploy, and is positioned toward the rear of the seat between the pair of front and rear chambers, as the gas is supplied from the pair of front and rear chambers, and is positioned toward the front of the seat in front of the occupant; wherein, in a front view taken from the front of the seat, the pair of front and rear chambers are folded toward the lower side of the seat relative to the airbag body and stored in the headrest of the vehicle seat; and in a side view taken from the width direction of the seat, the gas outlet ejected from the inflator is located in the vertical center of the pair of front and rear chambers toward the rear of the seat.

[0008] According to the first embodiment of the invention, when a vehicle collides, 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, and as gas is supplied from the pair of front and rear chambers, it 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. Note that "at the time of collision" here also includes when the inevitability of a collision is predicted (foreseen).

[0009] In this configuration, when viewed from the front of the seat, the pair of front and rear chambers of the airbag body are folded downwards toward the seat and stored in the headrest of the vehicle seat. When viewed from the side in the direction of the seat width, the gas outlet for the inflator is located in the vertical center of the pair of front and rear chambers on the rear side of the seat.

[0010] Therefore, at the start of inflation and deployment of the pair of front and rear chambers, the vertical center of the pair of front and rear chambers on the rear side of the seat can be pushed forward towards the seat, stabilizing the deployment direction of the pair of front and rear chambers. In other words, the deployment behavior of the airbag body, which is positioned in front of the occupant's seat, is stabilized by inflating and deploying through the space between the occupant's head and the ceiling of the vehicle. Note that the "vertical center" referred to here includes the approximate vertical center, which is slightly offset vertically from the center.

[0011] Furthermore, a second embodiment of the seat-mounted airbag device according to the present invention is a seat-mounted airbag device according to the first embodiment, comprising a distribution pipe provided on the vehicle seat and capable of supplying gas ejected from the inflator to a pair of front and rear chambers, respectively, wherein the distribution pipe has nozzles connected to the base of the pair of front and rear chambers, respectively, and the nozzles, in a side view taken from the seat width direction, extend a predetermined length toward the front and upper side of the seat and are located in the vertical center of the pair of front and rear chambers on the rear side of the seat.

[0012] According to the second embodiment of the invention, the vehicle seat is provided with a distribution pipe capable of supplying gas ejected from an inflator to a pair of front and rear chambers, respectively, and the distribution pipe has nozzles connected to the base of the pair of front and rear chambers. The nozzles extend for a predetermined length toward the front and upper side of the seat when viewed from the seat width direction, and are located in the vertical center of the pair of front and rear chambers on the rear side of the seat.

[0013] Therefore, at the start of inflation and deployment of the pair of front and rear chambers, the vertically central portion of the pair of front and rear chambers on the rear side of the seat can be more effectively pushed forward of the seat, stabilizing the deployment direction of the pair of front and rear chambers. In addition, since a distribution pipe is provided, the mounting position of the inflator is not restricted. Therefore, for example, the inflator can be mounted along the extending direction of the seat back, suppressing the enlargement (increase in thickness) of the seat back. Note that the "vertically central portion" referred to here also includes the vertically approximate central portion that is slightly offset vertically from the center.

[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 or second embodiment, wherein the base portions of the pair of front and rear chambers connected to the nozzle are housed in the headrest in a state where they are bent upward in a convex shape when viewed from the seat width direction in a side view.

[0015] According to the third embodiment of the invention, the base portions of a pair of front and rear chambers connected to the nozzle are stored in a state where they are bent upward in a convex shape when viewed from the side in the width direction of the sheet. Therefore, when the base portions of the pair of front and rear chambers expand, the vertically central portion of the front and rear chambers on the rear side of the sheet is pushed out toward the front and lower side of the sheet, thereby more effectively stabilizing the deployment direction of the pair of front and rear chambers. [Effects of the Invention]

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

[0017] [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]It is a schematic side view showing a state where the airbag of the seat-mounted airbag device according to the first 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 first embodiment is inflated and deployed. [Figure 4] It is a schematic plan view showing the shape of the airbag before folding in the first embodiment. [Figure 5] (A) It is a schematic enlarged cross-sectional view taken along the line X-X of FIG. 4. (B) It is a schematic enlarged cross-sectional view taken along the line Y-Y of FIG. 4. [Figure 6] (A) to (F) It is a schematic plan view showing the folding process of the airbag in the first embodiment. [Figure 7] It is a schematic plan view showing the shape of the airbag after folding in the first embodiment. [Figure 8] It is a schematic front view showing a partial cross-section of the airbag stored in the headrest in the first embodiment. [Figure 9] It is a schematic front view showing the shape of the distribution pipe in the first embodiment with the airbag omitted in a partial cross-section. [Figure 10] It is a schematic side view showing a partial cross-section of the airbag stored in the headrest in the first embodiment. [Figure 11] It is a schematic plan view showing a partial cross-section of the airbag stored in the headrest in the first embodiment. [Figure 12] It is a schematic side view showing the initial stage of inflation and deployment of the airbag in the first embodiment. [Figure 13] It is a schematic side view showing the middle stage of inflation and deployment of the airbag in the first embodiment. [Figure 14] It is a schematic side view showing the late stage of inflation and deployment of the airbag in the first embodiment. [Figure 15] (A) It is a schematic side view showing a partial cross-section of the state before supplying gas to the airbag in the second embodiment. (B) It is a schematic side view showing a partial cross-section of the state immediately after supplying gas to the airbag in the second embodiment. [Modes for carrying out the invention]

[0018] 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.

[0019] <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 12 to 14).

[0020] 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".

[0021] 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 of the seat cushion 14 in a side view from the seat width direction and is rotatable in the seat width direction, supporting the occupant D's back. 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 10).

[0022] 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.

[0023] The airbag system 30 comprises an airbag 32 and a single inflator 44 (see Figures 9 and 10). The airbag 32 is normally stored inside the headrest 18 in a folded state (see Figures 8, 10, and 11). 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.

[0024] 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.

[0025] 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 9 and 10). 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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)).

[0030] 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.

[0031] 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.

[0032] Furthermore, as shown in Figures 4 and 5(A), 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. 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 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.

[0033] In this state, the airbag 32 is folded, as shown in Figure 6. Specifically, first, as shown in Figures 6(A) to 6(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.

[0034] 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-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 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.

[0035] As shown in Figure 7, 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 8.

[0036] 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. In the airbag 32 shown in Figure 8 before the pair of front and rear chambers 34 are folded downwards, the length from the center line of the airbag body 40 in the seat width direction (not shown) to the outer ends of the front and rear chambers 34 in the seat width direction is 200 mm to 400 mm, and the position of the boundary 42 is approximately 100 mm to 200 mm from the outer ends of the front and rear chambers 34 in the seat width direction.

[0037] 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.

[0038] Furthermore, as shown in Figure 9, 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."

[0039] As shown in Figure 10, 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.

[0040] 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.

[0041] Furthermore, as shown in Figure 11, 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.

[0042] As shown in Figures 4 and 6(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 10, 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 10) are located approximately in the vertical center on the rear side of the pair of front and rear chambers 34.

[0043] 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 10) 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, 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.

[0044] 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.

[0045] 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).

[0046] Furthermore, the airbag unit 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 unit 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 Figures 12 to 14).

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] The operation of the airbag device 30 according to the first embodiment, which has the configuration described above, will now be explained.

[0054] The airbag 32, which has a pair of front and rear chambers 34 and an airbag body 40, is stored in the headrest 18 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.

[0055] 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.

[0056] When a frontal collision of the vehicle is detected (or predicted) by the collision sensor, the inflator 44 is activated under the control of the control device. 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.

[0057] Then, the tear line of the headrest 18 is opened by the inflation pressure of the pair of front and rear chambers 34 and the inflation pressure of the rear connecting portion 34C via the airbag body 40, that is, the inflated rear connecting portion 34C is subjected to a pressing force that pushes the airbag body 40, which is folded into a roll shape, toward the front.

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

[0059] Therefore, at the start of expansion and deployment of the pair of front and rear chambers 34 when gas begins to be ejected from each nozzle 46A, the approximately central part in the vertical direction on the rear side of the pair of front and rear chambers 34 can be effectively pushed forward, thereby stabilizing the deployment direction of the pair of front and rear chambers 34.

[0060] For example, if the outlets 46A in the left and right branch pipes 46 of the distribution pipe 50 that supplies gas ejected from the inflator 44 to a pair of front and rear chambers 34 are located at the lower rear end of the pair of front and rear chambers 34 in a side view, then when the expansion and deployment of the pair of front and rear chambers 34 begins, the pair of front and rear chambers 34 will be tilted backward, making it difficult to push the pair of front and rear chambers 34 forward.

[0061] In contrast, in this embodiment, because of the above-described configuration, the problem of the pair of front and rear chambers 34 tilting backward does not occur, and the deployment direction of the pair of front and rear chambers 34 is stabilized. As a result, as shown in Figure 12, the pair of front and rear chambers 34 expand and deploy forward from the front of the headrest 18, passing through both the left and right sides of the occupant D's head H.

[0062] Furthermore, this stabilizes the deployment behavior of the airbag body 40 as it moves in conjunction with the inflation and deployment of the pair of front and rear chambers 34. Therefore, the airbag body 40, when folded into a roll shape, can move forward through the narrow gap between the head H of the occupant D and the ceiling 28 of the vehicle compartment, above the head H of the occupant D, as the pair of front and rear chambers 34 inflate and deploy.

[0063] 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.

[0064] 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.

[0065] Thus, after the front and rear chambers 34 have finished inflating and deploying, 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 of the front and rear chambers 34 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.

[0066] 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.

[0067] Furthermore, in this embodiment, since the distribution pipe 50 is provided inside the headrest 18, there are no restrictions on the mounting position of the inflator 44. Therefore, for example, the inflator 44 can be installed along the extending direction of the seat back 16 (with the axial direction facing up and down), either inside the seat back 16 or spanning from inside the seat back 16 to inside the headrest 18, thereby suppressing an increase in the size (thickness) of the seat back 16 and headrest 18.

[0068] 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.

[0069] 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.

[0070] 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).

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] <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.

[0077] As shown in Figure 15(A), the airbag device 30 according to this second embodiment differs from the first embodiment in that the left base portion 36L and the right base portion 36R (only the left base portion 36L is shown in Figure 15) of the pair of front and rear chambers 34, which are connected to each nozzle 46A in the left branch pipe 46L and the right branch pipe 46R (only the left branch pipe 46L is shown in Figure 15), are folded in an upward convex shape (a roughly arc shape that is convex upwards) in a side view and housed in the headrest 18.

[0078] Thus, when the left and right base portions 36L and 36R of the pair of front and rear chambers 34, which are connected to the respective nozzles 46A of the left and right branch pipes 46L and 46R of the distribution pipe 50, are stored in a state where they are bent upward in a convex shape when viewed from the side, as shown in Figure 15(B), when gas is supplied from each nozzle 46A, the left and right base portions 36L and 36R expand and unfold, so that the upper part of the rear side of the pair of front and rear chambers 34 can be pressed forward and downward by the expanded left and right base portions 36L and 36R.

[0079] Furthermore, the expanded and deployed left and right base portions 36L and 36R supply (inject) gas to the approximately central vertical portion on the rear side of the pair of front and rear chambers 34 from the rear upper side to the front lower side in a side view. This makes it possible to more effectively push the pair of front and rear chambers 34 forward and downward. Therefore, the deployment direction of the pair of front and rear chambers 34 can be more effectively stabilized.

[0080] 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.

[0081] For example, 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.

[0082] Although not shown in the diagram, the headrest 18 may be constructed without providing a distribution pipe 50 inside, and the nozzles 44A of the three inflators 44 may be directly connected to the respective base sections 36L, 36R, and 38. In this case, the thickness of the headrest 18 will increase as each inflator 44 protrudes diagonally downward and rearward. However, the same effect as described above can be obtained by positioning the nozzles 44A of the two inflators 44 directly connected to the left and right base sections 36L and 36R, respectively, approximately in the vertical center on the rear side of the pair of front and rear chambers 34. [Explanation of symbols]

[0083] 12 Vehicle seats 18 Headrests 28 Ceiling 30 Airbag system 32 airbags 34 Front and rear chambers 36. Root area 40 Airbag Unit 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, In a front view from the front of the seat, the folded airbag body is folded in a way that follows the upper surface and both left and right sides of the outer shape of the headrest, and the pair of front and rear chambers are folded downwards towards the seat and stored in the headrest. A seat-mounted airbag device in which, in a side view taken from the seat width direction, the gas outlet ejected from the inflator is located in the vertical center of the pair of front and rear chambers on the rear side of the seat.

2. The vehicle seat is provided with distribution pipes capable of supplying gas ejected from the inflator to the pair of front and rear chambers, respectively. The distribution pipe has nozzles that are connected to the bases of the pair of front and rear chambers, The seat-mounted airbag device according to claim 1, wherein the nozzle extends for a predetermined length toward the front and upper side of the seat in a side view taken from the seat width direction, and is located in the vertical center of the pair of front and rear chambers on the rear side of the seat.

3. The seat-mounted airbag device according to claim 1 or claim 2, wherein the base portions of the pair of front and rear chambers connected to the nozzle are stored in the headrest in a state where they are bent upward in a convex shape when viewed from the seat width direction in a side view.

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