Seat-mounted airbag device

Abstract

To obtain a seat loading type air bag device which can suppress backward tilt of a neck part of a crewman when arresting the head of the crewman.SOLUTION: A seat loading type air bag device 30 comprises an air bag body 32 having: front and rear chambers 34 which pass a lateral side of a head Ph of a crewman P and expand to a front side by a gas injected from an inflator operated by collision of a vehicle, and are located on the lateral side of the head Ph of the crewman P; a tip chamber 36 which expands to a seat width direction inner side from a front side end part of the front and rear chambers 34, and is located on a front side of the face of the crewman P; an upper tether which connects an expansion direction intermediate part at an upper end part of the front and rear chambers 34 and an expansion direction intermediate part at an upper end part of the tip chamber 36; and a lower tether 38 which connects an expansion direction intermediate part at a lower end part of the front and rear chambers 34 and an expansion direction intermediate part at a lower end part of the tip chamber 36. The air bag body 32 is so configured as to include at least the lower tether 38 and extend to the front side when arresting the head of the crewman P.SELECTED DRAWING: Figure 5

Description

Technical Field

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

Background Art

[0002] A side airbag device is conventionally known (see, for example, Patent Document 1), which includes an airbag main body portion that expands forward from one side portion of a seat back during a collision from an obliquely forward direction of a vehicle and is disposed on the side of an upper body (including the head) of an occupant, and an airbag protruding portion that expands inward in the seat width direction from the airbag main body portion and is disposed in front of the face of the occupant, and the two are connected to each other by a planar tether.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, since the side airbag device is configured to restrain only the head of the occupant moving obliquely forward by the airbag protruding portion disposed in front of the face of the occupant, when restraining the head of the occupant, the amount of movement of the head of the occupant forward may be smaller than the amount of movement of the chest of the occupant forward determined by the restraining force of the seat belt, and the backward tilt (hyperextension) of the neck of the occupant may increase.

[0005] Therefore, an object of the present invention is to provide a seat-mounted airbag device that can suppress the backward tilt of the neck of an occupant when restraining the head of the occupant.

Means for Solving the Problems

[0006] To achieve the above object, according to the present invention The 1 aspect The seat-mounted airbag device is deployed from the inflator activated by detecting or predicting a vehicle collision through the side of the occupant's head to the front side of the seat by the gas ejected from the inflator, and includes a front-rear chamber disposed on the side of the occupant's head, a tip chamber that is deployed from the front-end portion on the seat front side of the front-rear chamber inward in the seat width direction and disposed on the front side of the seat of the occupant's face, an upper tether that connects the intermediate portion in the deployment direction at the upper end of the front-rear chamber and the intermediate portion in the deployment direction at the upper end of the tip chamber, and a lower tether that connects the intermediate portion in the deployment direction at the lower end of the front-rear chamber and the intermediate portion in the deployment direction at the lower end of the tip chamber. The airbag body is configured to extend at least including the lower tether to the front side of the seat when restraining the occupant's head.

[0007] The 1 aspect According to the invention of 1, when a vehicle collision is detected or predicted, the inflator is activated to eject gas, and the front-rear chamber is deployed from the side of the occupant's head to the front side of the seat and disposed on the side of the occupant's head. Then, the tip chamber is deployed from the front-end portion on the seat front side of the front-rear chamber inward in the seat width direction and disposed on the front side of the seat of the occupant's face. Here, the airbag body has an upper tether that connects the intermediate portion in the deployment direction at the upper end of the front-rear chamber and the intermediate portion in the deployment direction at the upper end of the tip chamber, and a lower tether that connects the intermediate portion in the deployment direction at the lower end of the front-rear chamber and the intermediate portion in the deployment direction at the lower end of the tip chamber. And the airbag body is configured to extend at least including the lower tether to the front side of the seat when restraining the occupant's head. Therefore, when restraining the occupant's head, it is suppressed that the amount of movement of the occupant's head to the front side of the seat becomes smaller than the amount of movement of the occupant's chest to the front side of the seat determined by the restraining force of the seat belt, and the backward tilt of the occupant's neck is suppressed.

[0008] Also, The 2 aspect The seat-mounted airbag device of The 1 aspect A seat-mounted airbag device, wherein the upper tether is an upper surface tether that covers the upper part of the space surrounded by the front-rear chamber and the tip chamber, and the lower tether is a lower surface tether that covers the lower part of the space surrounded by the front-rear chamber and the tip chamber, and the rear end of the lower surface tether on the seat rear side is notched in a substantially arc shape.

[0009] The 2 aspect According to the invention of 2, the upper tether is an upper surface tether that covers the upper part of the space surrounded by the front-rear chamber and the tip chamber, and the lower tether is a lower surface tether that covers the lower part of the space surrounded by the front-rear chamber and the tip chamber. And the rear end of the lower surface tether on the seat rear side is notched in a substantially arc shape. Therefore, compared with the case where the rear end of the lower surface tether on the seat rear side is formed in a straight line, the line length at the rear end of the lower surface tether on the seat rear side becomes longer, and it is difficult to inhibit the movement of the airbag body (especially the tip chamber) to the front side of the seat. Thus, when restraining the occupant's head, it is suppressed that the amount of movement of the occupant's head to the front side of the seat becomes small, and the backward tilt of the occupant's neck is suppressed.

[0010] Also, The 3 aspect The seat-mounted airbag device of 3 is The 2 aspect A seat-mounted airbag device, wherein the maximum curvature part at the rear end of the lower surface tether on the seat rear side is located on the tip chamber side with respect to a virtual straight line along the front-rear direction of the seat passing through the center of gravity of the occupant's head in plan view.

[0011] The 3 aspect According to the invention, the maximum curvature portion at the rear end of the seat of the lower surface tether is located on the tip chamber side with respect to the virtual straight line along the longitudinal direction of the seat passing through the center of gravity of the occupant's head in plan view. Therefore, for example, compared with the case where the maximum curvature portion at the rear end of the seat of the lower surface tether is located on the virtual straight line along the longitudinal direction of the seat passing through the center of gravity of the occupant's head in plan view, when restraining the occupant's head, the amount of movement of the occupant's head toward the front side of the seat is more effectively suppressed, and the tip of the tip chamber is more likely to bend toward the rear side of the seat. Thus, even if the wire length at the rear end of the seat of the lower surface tether becomes longer, the occupant's head is suppressed from slipping out of the airbag body (especially the tip chamber).

[0012] Also, The 4 aspect The seat-mounted airbag device of The 2 or The 3 aspect is a seat-mounted airbag device, and the lower surface tether is a tether chamber that is deployed by the gas ejected from the inflator.

[0013] The 4 aspect According to the invention, the lower surface tether is a tether chamber that is deployed by the gas ejected from the inflator. Therefore, compared with the case where the lower surface tether is not a tether chamber that is deployed by the gas ejected from the inflator, when restraining the occupant's head, even if the lower surface tether hits the occupant's neck, the load on the occupant's neck by the lower surface tether is reduced.

[0014] Also, The 5 aspect The seat-mounted airbag device of The 1 to The any one of 3 two aspects is a seat-mounted airbag device, and the upper tether and the lower tether are formed of a material that extends more than the base fabric of the airbag body.

[0015] The 5aspect According to the invention, the upper tether and the lower tether are formed of a material that stretches more than the base fabric of the airbag body. Therefore, when restraining the occupant's head, the upper tether and the lower tether stretch due to the tensile load acting on them. Thus, when restraining the occupant's head, it is suppressed that the amount of movement of the occupant's head toward the front side of the seat decreases, and the backward tilt of the occupant's neck is suppressed.

[0016] Also, The 6 aspect The seat-mounted airbag device of The 1 to The any one of 5 two aspects is a seat-mounted airbag device, and a plurality of circular seam portions are formed side by side in the front-rear direction of the seat at the center in the up-down direction of the seat of at least the tip chamber.

[0017] The 6 aspect According to the invention, a plurality of circular seam portions are formed side by side in the front-rear direction of the seat at the center in the up-down direction of the seat of at least the tip chamber. Therefore, compared with the case where a plurality of seam portions are formed side by side in the up-down direction of the seat, the tip chamber is more likely to bend in the up-down direction of the seat. Thus, when restraining the occupant's head, it is suppressed that the amount of movement of the occupant's head toward the front side of the seat decreases, and the backward tilt of the occupant's neck is suppressed.

[0018] Also, The 7 aspect The seat-mounted airbag device of The 1 to The any one of 5 two aspects is a seat-mounted airbag device, and a seam portion extending in the front-rear direction of the seat is formed at the center in the up-down direction of the seat of at least the tip chamber.

[0019] The 7 aspect According to the invention, a seam portion extending in the front-rear direction of the seat is formed at least at the center in the up-down direction of the seat of the tip chamber. Therefore, compared with the case where a seam portion extending in the up-down direction of the seat is formed, the tip chamber is more likely to bend in the up-down direction of the seat. Thus, when restraining the occupant's head, it is suppressed that the amount of movement of the occupant's head toward the front side of the seat becomes small, and the backward tilt of the occupant's neck is suppressed.

[0020] Also, The 8 aspect The seat-mounted airbag device of The 1 to The any one of 7 two aspects is a seat-mounted airbag device, wherein the front-rear chamber is bent and formed in the up-down direction or the width direction of the seat, and has a connecting member that connects the front end portion and the rear end portion on the seat side at the shortest distance, and the connecting member is configured to release the connection by a tensile load equal to or greater than a predetermined value acting when restraining the occupant's head.

[0021] The 8 aspect According to the invention of

[0022] Also, The 9 aspect The seat-mounted airbag device of The 1 to The any one of 7 two aspects is a seat-mounted airbag device, wherein the front-rear chamber is composed of a plurality of divided chambers arranged in the front-rear direction of the seat, and the divided chambers are configured to extend toward the front side of the seat when restraining the occupant's head.

[0023] The 9 aspect According to the invention, the front-rear chamber is composed of a plurality of divided chambers arranged in the front-rear direction of the seat, and the divided chambers are configured to extend toward the front side of the seat when restraining the occupant's head. Therefore, when restraining the occupant's head, it is suppressed that the amount of movement of the occupant's head toward the front side of the seat becomes small, and the backward tilt of the occupant's neck is suppressed.

[0024] Also, The 10 aspect the seat-mounted airbag device of The 1 to The any one of 7 two aspects is a seat-mounted airbag device, wherein the front-rear chamber is formed in a bellows shape folded in the front-rear direction of the seat and is sewn with a thread so as to maintain the bellows shape, and the thread is configured to break by a tensile load equal to or greater than a predetermined value acting when restraining the occupant's head.

[0025] The 10 aspect According to the invention, the front-rear chamber is formed in a bellows shape folded in the front-rear direction of the seat and is sewn with a thread so as to maintain the bellows shape. And the thread is configured to break by a tensile load equal to or greater than a predetermined value acting when restraining the occupant's head. That is, when the thread breaks, the front-rear chamber extends toward the front side of the seat. Therefore, when restraining the occupant's head, it is suppressed that the amount of movement of the occupant's head toward the front side of the seat becomes small, and the backward tilt of the occupant's neck is suppressed.

Effect of the Invention

[0026] As described above, according to the present invention, in the seat-mounted airbag device, it is possible to suppress the backward tilt of the occupant's neck when restraining the occupant's head.

Brief Description of the Drawings

[0027]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

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Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Embodiments for Carrying Out the Invention

[0028] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. For convenience of explanation, in each figure, the arrow UP shown as appropriate is the upward direction on the seat, the arrow FR is the forward direction of the seat, and the arrow RH is the rightward direction of the seat. Therefore, in the following description, when the directions of up and down, front and back, left and right are described without special mention, they indicate up and down, front and back, left and right in the vehicle seat. Also, the left and right directions are synonymous with the seat width direction.

[0029] As shown in FIGS. 1 to 3, a seat-mounted airbag device (hereinafter simply referred to as "airbag device") 30 according to the present embodiment is provided inside a case portion 20 that constitutes a headrest 16 of a vehicle seat 10 serving as a rear seat of a vehicle. Therefore, although the vehicle seat 10 according to the present embodiment will be described as a rear seat, this airbag device 30 may be provided in a front seat.

[0030] Further, as an example, the rear seat is a rear seat on the left side window 18 (see FIG. 3) side. As will be described later, the airbag main body 32 will be described by taking as an example the case where it expands through between the head Ph of the occupant P on the side window 18 side and the head of the occupant on the center seat side (not shown). However, the airbag main body 32 may be configured to expand through between the side window 18 and the head Ph of the occupant P. Further, the "occupant P" in the present embodiment is, as an example, an occupant corresponding to AM50 (50th percentile of an adult male in the United States) of WorldSID (International Unified Side Impact Dummy: World Side Impact Dummy).

[0031] <First Embodiment> First, the airbag device 30 according to the first embodiment will be described. As shown in FIGS. 1 and 2, the vehicle seat 10 has a seat cushion 12 on which the occupant P sits (supporting the buttocks and thighs of the occupant P), a seat back 14 supporting the back of the occupant P, and a headrest 16 supporting the head Ph of the occupant P.

[0032] As shown in FIG. 3, the headrest 16 has a block-shaped main body portion 16A provided so as to be able to move up and down at the center in the seat width direction at the upper end portion of the seat back 14. More specifically, a pair of left and right columnar headrest stays (not shown) are provided at the center in the seat width direction on the lower surface of the main body portion 16A.

[0033] Each headrest stay is inserted into a substantially cylindrical headrest support 26 provided in a pair on the left and right at the center in the seat width direction at the upper end of the seat back 14 so as to be vertically movable and fixable at a plurality of predetermined positions. Accordingly, the height position of the headrest can be adjusted according to the position of the head Ph of the occupant P. And the headrest 16 has a case portion 20 continuously provided from the rear of the main body portion 16A to both left and right sides. 16 The case portion 20 is formed in a substantially "U" shape with the front side open in plan view. And the main body portion 16A of the headrest 16 is disposed almost without a gap inside the case portion 20. In the case portion 20, the front end surfaces (the outer surfaces of the front wall 20F) of the left and right side portions 24 extending in the front-rear direction are substantially flush with the front surface of the main body portion 16A.

[0034] Moreover, the left and right outer walls 20A and the rear wall 20B (of the side portions 24) in the case portion 20 are constituted by a resin cover member 22 formed in a substantially "U" shape in plan view. And the upper wall 20U (see FIGS. 1 and 2), the lower wall (not shown), the front wall 20F, and the inner peripheral wall 20C facing the main body portion 16A in the case portion 20 are configured to include a urethane foam (not shown) having a predetermined thickness, and the outer surfaces of the cover member 22 and the urethane foam are integrally covered with the skin material 21.

[0035] A predetermined space portion S (including a storage portion S1 and an arrangement portion S2 to be described later) is formed inside the case portion 20. And the airbag main body 32 of the airbag device 30 is stored in the storage portion S1 formed in the side portion 24R on the side opposite to the side window 18 side (the right side in the figure which is the center seat side) in the case portion 20. The configuration of the airbag main body 32 will be described in detail later.

[0036]

[0037] ​An inflater 28 is disposed in a disposition portion S2 which is on the rear side of a space portion S formed in a case portion 20. The inflater 28 is formed in a substantially bottomed cylindrical shape, and its outer peripheral portion is supported by a reaction force plate (not shown) formed in a housing shape via a retainer (not shown) so that its axial center portion is disposed along the seat width direction.

[0038] The reaction force plate is fixed to, for example, a seat back frame (not shown) via a bracket (not shown), and is configured to receive a reaction force transmitted from an airbag body 32 that deploys forward via the inflater 28. Note that the reaction force plate and the retainer are also disposed in the disposition portion S2.

[0039] The inflater 28 is electrically connected to an airbag ECU (not shown) provided in the vehicle, and a detection device (not shown) such as an acceleration sensor provided in the vehicle and the airbag ECU are electrically connected. Therefore, when a collision of the vehicle is detected by the detection device, the inflater 28 operates via the airbag ECU and instantaneously ejects gas.

[0040] Note that the inflater 28 may be configured to operate when a collision of the vehicle is predicted by a collision prediction sensor or the like (not shown), instead of being configured to operate when a collision of the vehicle is detected. And a connection portion 31 of the airbag body 32 is fitted and connected to an ejection port of the inflater 28.

[0041] As shown in FIGS. 1 and 2, the airbag device 30 has an airbag body 32 that deploys from the rear side (specifically, the right rear side) to the front side of the head Ph of an occupant P seated on a vehicle seat 10 when gas is ejected from the inflater 28 (see FIG. 3).

[0042] The airbag body 32 is deployed forward through the right side of the head Ph of the occupant P, and is disposed on the right side of the head Ph of the occupant P (between the head Ph of the occupant P on the side window 18 side and the head of the occupant on the center seat side) with a front-rear chamber 34, and is deployed inward in the seat width direction from the front end of the front-rear chamber 34, and has a tip chamber 36 disposed in front of the face of the occupant P and on the left side of the head Ph of the occupant P. That is, the airbag body 32 is bent in a substantially "J" shape in a bottom view so as to be able to restrain at least the head Ph of the occupant P.

[0043] Also, as shown in FIG. 2, the airbag body 32 has an upper tether 37 that connects the intermediate portion 34U in the deployment direction at the upper end of the front-rear chamber 34 and the intermediate portion 36U in the deployment direction at the upper end of the tip chamber 36. And, as shown in FIG. 4, the airbag body 32 has a lower tether 38 that connects the intermediate portion 34D in the deployment direction at the lower end of the front-rear chamber 34 and the intermediate portion 36D in the deployment direction at the lower end of the tip chamber 36.

[0044] More specifically, the upper tether 37 is a tether chamber that is deployed together when the airbag body 32 expands and deploys due to the gas ejected from the inflator 28. As shown in FIG. 2, in a plan view, it has a rear edge portion 37A that connects the intermediate portion 34U in the deployment direction at the upper end of the front-rear chamber 34 and the intermediate portion 36U in the deployment direction at the upper end of the tip chamber 36, and is an upper surface tether 37B that covers the upper part of the space surrounded by the front-rear chamber 34 and the tip chamber 36.

[0045] And, for the upper surface tether 37B, the peripheral edge portion excluding its rear edge portion 37A (rear side end portion) is attached by sewing to the upper end portion of the front-rear chamber 34 and the upper end portion of the tip chamber 36 from the intermediate portion 34U in the deployment direction at the upper end of the front-rear chamber 34 to the intermediate portion 36U in the deployment direction at the upper end of the tip chamber 36.

[0046] Similarly, the lower tether 38 is a tether chamber that unfolds together when the airbag body 32 expands and deploys due to the gas ejected from the inflator 28. As shown in FIG. 4, in plan view, it has a rear edge portion 38A that connects the intermediate portion 34D in the deployment direction at the lower end of the front-rear chamber 34 and the intermediate portion 36D in the deployment direction at the lower end of the tip chamber 36, and is a lower surface tether 38B that covers the lower part of the space surrounded by the front-rear chamber 34 and the tip chamber 36.

[0047] And, for the lower surface tether 38B, the peripheral edge portion excluding its rear edge portion 38A (rear side end portion) is sewn and attached to the lower end portion of the front-rear chamber 34 and the lower end portion of the tip chamber 36 from the intermediate portion 34D in the deployment direction at the lower end of the front-rear chamber 34 to the intermediate portion 36D in the deployment direction at the lower end of the tip chamber 36.

[0048] Also, this airbag body 32 is configured to extend forward at least including the lower surface tether 38B (lower tether 38) when restraining the head of the occupant P. That is, as shown in FIG. 4, the rear edge portion 38A of the lower surface tether 38B (lower tether 38) has a large notch in a substantially arc shape (mountain shape with a curve) between the intermediate portion 34D in the deployment direction of the front-rear chamber 34 and the intermediate portion 36D in the deployment direction of the tip chamber 36, and is configured such that its line length becomes longer compared to the case where the intermediate portion 34D in the deployment direction of the front-rear chamber 34 and the intermediate portion 36D in the deployment direction of the tip chamber 36 are linearly connected (indicated by the virtual straight line K).

[0049] Thereby, as shown in FIG. 5, when restraining the head of the occupant P, the tip chamber 36 can extend forward without being obstructed by the lower surface tether 38B, and the tip portion of the tip chamber 36 can be bent rearward from the starting point T1 (see FIG. 4) to restrain the left side of the head Ph of the occupant P. Here, the starting point T1 referred to here means the intersection point of the virtual straight line K1 drawn linearly along the rear edge portion 38A from the intermediate portion 34D in the deployment direction of the front-rear chamber 34 in plan view and the sewing portion of the lower surface tether 38B in the tip chamber 36.

[0050] Further, the shape of the rear edge portion 38A of the lower surface tether 38B is not limited to the shape shown in FIG. 5. As shown in FIG. 6, the rear edge portion 38A of the lower surface tether 38B is preferably notched in a substantially arc shape such that its maximum curvature portion 40 is located on the tip chamber 36 side (the side closer to the tip portion of the tip chamber 36) with respect to the virtual straight line Kc along the front-rear direction passing through the center of gravity of the head Ph of the occupant P in plan view (bottom view).

[0051] According to this, as shown in FIG. 7, when restraining the head of the occupant P, the tip chamber 36 can extend forward without being obstructed by the lower surface tether 38B more than that shown in FIGS. 4 and 5, and the tip portion of the tip chamber 36 can be bent rearward from the starting point T2 (see FIG. 6) to restrain the left side of the head Ph of the occupant P. Here, the starting point T2 refers to the intersection of the virtual straight line K2 linearly drawn from the middle portion 34D in the deployment direction of the front and rear chambers 34 to the rear edge portion 38A in plan view and the sewing portion of the lower surface tether 38B in the tip chamber 36.

[0052] Also, as shown in FIG. 3, the airbag body 32 is wound around in a roll shape with the vertical direction as the axial direction (in a state having a roll-shaped outer winding portion 32A on the outer side in the seat width direction in plan view) and is configured to be stored in the storage portion S1 formed in the side portion 24R. And a bellows portion 32B is formed continuously with the outer winding portion 32A on the upstream side in the deployment direction of the outer winding portion 32A.

[0053] That is, this airbag body 32 is stored in the storage portion S1 in a state having a bellows portion 32B that is continuously folded in a bellows shape from the outer winding portion 32A to the upstream side in the deployment direction. Therefore, when this airbag body 32 is deployed from the side portion 24R through the right side of the head Ph of the occupant P to the front side by the gas ejected from the inflator 28, first the bellows portion 32B unfolds while loosening, and then the outer winding portion 32A unfolds while loosening.

[0054] Note that the bellows 32B shown in FIG. 3 is formed in only two sets when two folded portions are taken as one set, but it is not limited to this. The bellows 32B may be formed in a plurality of sets, and may be formed in three or more sets.

[0055] Further, the front wall 20F constituting the front end face of the side portion 24R is broken along a straight line along the vertical direction in a front view, for example, together with a part of the upper wall 20U on the front wall 20F side as the airbag body 32 is deployed. The broken portion is preferably the inner end portion 20N in the seat width direction of the front wall 20F.

[0056] When the broken portion is the inner end portion 20N in the seat width direction of the front wall 20F (for example, when a vulnerable portion or the like that is easily broken is formed at the inner end portion 20N in the seat width direction of the front wall 20F), the front wall 20F will be opened with the outer end portion 20T in the seat width direction as a hinge portion.

[0057] Next, the operation of the airbag device 30 according to the first embodiment configured as described above will be described.

[0058] When a detection device detects that the vehicle has collided head-on, the inflator 28 operates and instantly ejects gas into the airbag body 32. When the gas is ejected into the airbag body 32, the front wall 20F of the side portion 24R breaks together with a part of the upper wall 20U on the front wall 20F side due to the deployment of the airbag body 32 (due to being pressed from the inside by the airbag body 32).

[0059] Then, the airbag body 32 deploys forward through the right side of the head Ph of the occupant P from the side portion 24R (the gap between the head Ph of the occupant P on the side window 18 side and the head of the occupant on the center seat side). That is, the airbag body 32 first unfolds while the bellows 32B that is folded in a bellows shape unfolds, and then the outer winding portion 32A that is wound around in a roll unfolds while unfolding.

[0060] Here, it is generally known that a bellows shape unfolds faster than a roll shape (the bellows shape has less resistance when unfolding than the roll shape). Therefore, compared to the airbag body 32 having only the outer winding portion 32A, the airbag body 32 having the outer winding portion 32A and the bellows portion 32B in order from the downstream side in the deployment direction can deploy more quickly toward the front side.

[0061] Then, when the front and rear chambers 34 expand and deploy and are arranged on the right side of the head Ph of the occupant P, gas flows from the front end portion of the front and rear chambers 34 into the tip chamber 36, and the tip chamber 36 expands and deploys inward in the seat width direction. Also, gas flows into the upper surface tether 37B and the lower surface tether 38B, and the upper surface tether 37B and the lower surface tether 38B expand and deploy.

[0062] In this way, at least the head Ph of the occupant P sitting on the vehicle seat 10 is restrained by the fully deployed airbag body 32 (front and rear chambers 34 and tip chamber 36). That is, the airbag body 32 (front and rear chambers 34 and tip chamber 36) can suppress at least the head Ph of the occupant P from moving forward due to inertial force.

[0063] Here, the airbag body 32 is configured to extend forward at least including the lower surface tether 38B when restraining the head Ph of the occupant P who tries to move forward due to inertial force. Specifically, the rear edge portion 38A of the lower surface tether 38B (between the intermediate portion 34D in the deployment direction of the front and rear chambers 34 and the intermediate portion 36D in the deployment direction of the tip chamber 36) is largely cut out in a substantially arc shape.

[0064] Therefore, compared to the case where the rear edge portion 38A of the lower surface tether 38B is formed in a straight line, the line length at the rear edge portion 38A of the lower surface tether 38B becomes longer, and it is difficult for the lower surface tether 38B to inhibit (or does not inhibit) the airbag body 32 (especially the tip chamber 36) from extending forward.

[0065] Therefore, when restraining the occupant P's head, it is possible to suppress a decrease in the amount of forward movement of the occupant P's head Ph (a reduction in the stroke amount) relative to the amount of forward movement of the occupant P's chest determined by the restraining force of the seat belt (not shown), and it is possible to suppress backward tilting (backward bending) of the occupant P's neck caused by the airbag body 32 (especially the tip chamber 36) not extending forward. Moreover, since the rear edge portion 38A of the lower surface tether 38B is largely cut out in a substantially arc shape, even if it is located on the occupant P's neck (even if it hits the occupant P's neck), the load on the occupant P's neck by the lower surface tether 38B can be reduced.

[0066] As described above, it is preferable that the rear edge portion 38A of the lower surface tether 38B is cut out in a shape such that its maximum curvature portion 40 is located on the tip chamber 36 side with respect to the virtual straight line Kc along the front-rear direction passing through the center of gravity of the occupant P's head Ph in plan view (bottom view). According to this, for example, compared with the case where the maximum curvature portion of the rear edge portion 38A of the lower surface tether 38B is located on the virtual straight line Kc passing through the center of gravity of the occupant P's head Ph in plan view (bottom view), when restraining the occupant P's head, it is possible to more effectively suppress a decrease in the amount of forward movement of the occupant P's head Ph, and the tip of the tip chamber 36 is more likely to bend backward. Therefore, even if the line length of the rear edge portion 38A of the lower surface tether 38B becomes long, it is possible to suppress the occupant P's head Ph from slipping through the airbag body 32 (especially the tip chamber 36).

[0067] Also, this lower surface tether 38B is a tether chamber that is deployed by the gas ejected from the inflator 28. Therefore, compared with the case where the lower surface tether 38B is not a tether chamber that is deployed by the gas ejected from the inflator, even if the lower surface tether 38B interferes with (hits) the occupant P's neck when restraining the occupant P's head, the load on the occupant P's neck by the lower surface tether 38B can be more effectively reduced. Note that since the upper tether 37 (upper surface tether 37B) is located above the occupant P's head Ph, it does not interfere with (hit) the occupant P's head Ph.

[0068] Also, as described above, the airbag body 32 unfolds forward while the externally wound outer winding portion 32A loosens. Therefore, when the airbag body 32 unfolds, there is no risk of the face of the occupant P being injured by the airbag body 32. Moreover, when the airbag body 32 unfolds, if the front wall 20F is configured to be opened with the outer end portion 20T in the seat width direction as a hinge portion, the airbag body 32 can prevent the unfolding front wall 20F from contacting the head Ph of the occupant P.

[0069] <Second Embodiment> Next, the airbag device 30 according to the second embodiment will be described. Note that the same reference numerals are given to the parts equivalent to those in the first embodiment, and the detailed description (including the common operations) is omitted as appropriate.

[0070] As shown in FIG. 8, the airbag body 32 of the airbag device 30 according to the second embodiment is different from the first embodiment only in that a plurality (for example, a pair of two) of circular seam portions 42 are formed side by side in the vertical center portion of at least the tip chamber 36 in the front-rear direction.

[0071] In this way, when a plurality of circular seam portions 42 are formed side by side in the vertical center portion of the tip chamber 36, as shown in FIG. 9, the tip chamber 36 is likely to be deformed so as to bend in the vertical direction. In other words, the tip chamber 36 is more likely to be deformed into a curved shape that protrudes forward in a side view compared to the case where a plurality of seam portions 42 are formed side by side in the vertical direction. Therefore, when restraining the head of the occupant P, it is possible to suppress the reduction of the stroke amount of the head Ph of the occupant P toward the front side, and it is possible to effectively suppress the backward tilt of the neck of the occupant P.

[0072] Note that, instead of the seam portion 42, as shown in FIG. 10, a seam portion 44 extending in the front-rear direction may be formed at the vertical center portion of the tip chamber 36. Also in this case, similar operational effects can be obtained. That is, the tip chamber 36 is more likely to bend and deform in the vertical direction than when a seam portion extending in the vertical direction is formed. Therefore, when restraining the head of the occupant P, it is possible to suppress a reduction in the stroke amount of the front side of the head Ph of the occupant P, and it is possible to effectively suppress the backward tilt of the neck of the occupant P.

[0073] <Third Embodiment> Next, the airbag device 30 according to the third embodiment will be described. Note that the same reference numerals are given to the parts equivalent to those in the first embodiment, and the detailed description (including the common operations) is appropriately omitted.

[0074] As shown in FIG. 11, the airbag body 32 of the airbag device 30 according to the third embodiment is different from the first embodiment only in that the upper tether 37 and the lower tether 38 are not formed as tether chambers that are inflated by the gas ejected from the inflator 28, but are formed of a material that extends more than the base fabric of the airbag body 32. For example, the upper surface tether 37C and the lower surface tether 38C in the form of rubber having a predetermined thickness.

[0075] The upper surface tether 37C and the lower surface tether 38C configured in this way can extend in the direction in which the tip chamber 36 separates from the front-rear chamber 34. Therefore, when restraining the head of the occupant P, the upper surface tether 37C and the lower surface tether 38C extend in the separation direction due to the tensile load acting on the upper surface tether 37C and the lower surface tether 38C. Therefore, when restraining the head of the occupant P, it is possible to suppress a reduction in the stroke amount of the front side of the head Ph of the occupant P, and it is possible to effectively suppress the backward tilt of the neck of the occupant P.

[0076] <Fourth Embodiment> Next, the airbag device 30 according to the fourth embodiment will be described. The same reference numerals are given to the parts equivalent to those in the first embodiment, and detailed descriptions (including common operations) are omitted as appropriate.

[0077] As shown in FIG. 12, the airbag body 32 of the airbag device 30 according to the fourth embodiment has a front-rear chamber 34 bent in the vertical direction, and a connecting member 46 that connects the front end portion 34F and the rear end portion 34B thereof at the shortest distance. The only difference from the first embodiment is that the connecting member 46 is configured to break (release the connection) under a tensile load equal to or greater than a predetermined value that acts when restraining the head of the occupant P.

[0078] More specifically, the front-rear chamber 34 is divided vertically except for the front end portion 34F and the rear end portion 34B. The upper chamber 34A of the front-rear chamber 34 is bent in a substantially "Λ" shape upward, and the lower chamber 34C of the front-rear chamber 34 is bent in a substantially "V" shape downward.

[0079] The central portion in the vertical direction at the front end portion 34F of the front-rear chamber 34 and the central portion in the vertical direction at the rear end portion 34B are connected by the connecting member 46 at the shortest distance. A bracket 47 is provided at the rear end portion 34B shown in the figure, and the connecting member 46 is attached to the rear end portion 34B via the bracket 47.

[0080] The connecting member 46 is composed of a string-like member such as a thread and is set to break under a tensile load equal to or greater than a predetermined value that acts when restraining the head of the occupant P. Therefore, at the time of a frontal collision of the vehicle, the head Ph of the occupant P moving forward due to inertial force presses the airbag body 32 forward and moves it. When a predetermined tensile load is reached, the connecting member 46 breaks.

[0081] As a result, since the upper chamber 34A and the lower chamber 34C of the front and rear chambers 34 that are bent extend toward the front side, it is possible to suppress a reduction in the stroke amount of the head Ph of the occupant P toward the front side. Therefore, when restraining the head of the occupant P, it is possible to effectively suppress the backward tilting of the neck of the occupant P.

[0082] As shown in FIG. 13, the airbag body 32 of the airbag device 30 according to the fourth embodiment may have the front and rear chambers 34 bent in a substantially “Λ” shape in a plan view toward the outside in the seat width direction, and the front upper end portion of the front and rear chambers 34 below the upper tether 37 and the rear upper end portion of the front and rear chambers 34 (bracket 47 provided at the rear upper end portion of the front and rear chambers 34) may be connected by a connecting member 46 at the shortest distance. Also in this case, since the connecting member 46 is broken by a tensile load equal to or greater than a predetermined value acting when restraining the head of the occupant P, the same operational effects as described above can be obtained.

[0083] <Fifth Embodiment> Next, the airbag device 30 according to the fifth embodiment will be described. Note that the same reference numerals are given to the parts equivalent to those in the first embodiment, and detailed descriptions (including common operations) are omitted as appropriate.

[0084] As shown in FIG. 14, the airbag body 32 of the airbag device 30 according to the fifth embodiment is different from the first embodiment only in that the front and rear chambers 34 are constituted by a plurality of divided chambers 35 that communicate with each other so that gas can flow and are arranged integrally in the front-rear direction, and each divided chamber 35 is configured to extend toward the front side when restraining the head of the occupant P.

[0085] Each divided chamber 35 is formed in a substantially spherical shape with equal lengths in the vertical and front-rear directions and is configured to be extendable toward the front side. Therefore, when the vehicle collides with the front, when the airbag body 32 is pressed and moved toward the front side by the head Ph of the occupant P that moves toward the front side due to inertial force and the front and rear chambers 34 are pulled toward the front side, each divided chamber 35 extends toward the front side.

[0086] This can suppress the reduction in the stroke amount of the head Ph of the occupant P toward the front side, so that the backward tilting of the neck of the occupant P can be effectively suppressed when restraining the head of the occupant P. Each divided chamber 35 may be formed in a substantially cylindrical shape with the vertical direction as the longitudinal direction (axial direction).

[0087] <Sixth Embodiment> Finally, the airbag device 30 according to the sixth embodiment will be described. Note that the same reference numerals are given to the parts equivalent to those in the first embodiment above, and the detailed description (including the common operations) will be omitted as appropriate.

[0088] As shown in FIGS. 15(A) and 16, the airbag main body 32 of the airbag device 30 according to the sixth embodiment has a bellows portion 34J in which at least a part of the case portion 20 side of the front and rear chambers 34 is folded in a bellows shape in the front-rear direction, and is sewn with a thread 48 so as to maintain the bellows shape. The difference from the first embodiment above is only that the thread 48 is configured to break by a tensile load equal to or greater than a predetermined value acting on the bellows portion 34J when restraining the head of the occupant P.

[0089] More specifically, the front and rear chambers 34 are divided into two front and rear regions. The region on the front side is a normal chamber, but as shown in FIG. 16, the region on the rear side is a bellows portion 34J folded in a bellows shape. A communication passage 50 formed of a flexible tube or the like for passing gas is provided at the center in the vertical direction in the bellows portion 34J. That is, the bellows portion 34J of the front and rear chambers 34 is folded along a plurality of broken lines along the vertical direction above and below the communication passage 50, and the folded and overlapped portions are sewn along the vertical direction with the thread 48.

[0090] When the front and rear chamber 34 has such a configuration, when gas is ejected from the inflator 28 during a frontal collision of the vehicle, the gas flows through the communication passage 50 to the region on the front side of the front and rear chamber 34, and expands and deploys the region on the front side of the front and rear chamber 34. Then, as gas flows into the tip chamber 36 from the region on the front side of the front and rear chamber 34, the tip chamber 36 expands and deploys, and the airbag body 32 restrains the head Ph of the occupant P who tends to move forward by inertial force.

[0091] Then, due to the inertial force, the head Ph of the occupant P moving forward presses the airbag body 32 forward, and the front and rear chamber 34 is pulled forward. That is, a tensile load directed forward is applied to the bellows 34J, which is the region on the rear side of the front and rear chamber 34. When the tensile load exceeds a predetermined value, the thread 48 breaks.

[0092] As a result, the bellows-like folded portion in the bellows 34J unfolds, and as shown in FIG. 15(B), the region on the rear side of the front and rear chamber 34 extends forward together with the communication passage 50. Therefore, it is possible to suppress a reduction in the forward stroke amount of the head Ph of the occupant P, and it is possible to effectively suppress the backward tilt of the neck of the occupant P when restraining the head of the occupant P.

[0093] As described above, the seat-mounted airbag device 30 according to the present embodiment has been described with reference to the drawings. However, the seat-mounted airbag device 30 according to the present embodiment is not limited to the illustrated one, and can be appropriately designed and changed within a range not departing from the gist of the present invention. For example, the seat-mounted airbag device 30 according to the present embodiment may appropriately combine the configurations of each embodiment.

[0094] Also, the upper tether 37 and the lower tether 38 are the upper surface tether 37B and BelowIt is not limited to the partial surface tether 38B. For example, although illustration is omitted, a belt-shaped tether may be provided such that the front end portion (front edge portion) does not reach the upper and lower end portions of the tip chamber 36 so as not to cover only a part of the front side of the space surrounded by the front and rear chambers 34 and the tip chamber 36. Further, in the second embodiment, the seam portions 42 and 44 formed at the vertical center portion of the tip chamber 36 may also be formed at the front end portion of the front and rear chambers 34, respectively.

[0095] Further, in the fourth embodiment, the connecting member 46 may not be cut by a tensile load equal to or greater than a predetermined value acting when restraining the head of the occupant P, but may be configured to be detached from a bracket 47 provided at the rear end portion 34B (including the upper rear end portion shown in FIG. 13) of the front and rear chambers 34. Thus, the connecting member 46 may be configured such that the connection is released by a tensile load equal to or greater than a predetermined value acting when restraining the head of the occupant P.

Explanation of Reference Numerals

[0096] 28 Inflator 30 Airbag device (seat-mounted airbag device) 32 Airbag body 34 Front and rear chambers 35 Divided chamber 36 Tip chamber 37 Upper tether 37B Upper surface tether 38 Lower tether 38A Rear edge portion (rear end portion) 38B Lower surface tether 40 Maximum curvature portion 42 Seam portion 44 Seam portion 46 Connecting member 48 Thread Kc Virtual straight line P Occupant Ph Head

Claims

1. A gas ejected from an inflator activated by detecting or predicting a collision of a vehicle expands from the side of the occupant's head through the front side of the seat, and includes a front-rear chamber disposed on the side of the occupant's head, a tip chamber that expands inward in the seat width direction from the front-end portion of the front-rear chamber on the front side of the seat and is disposed on the front side of the seat of the occupant's face, and a lower surface tether that connects an intermediate portion in the deployment direction at the lower portion of the front-rear chamber and an intermediate portion in the deployment direction at the lower portion of the tip chamber and covers the lower portion of the space surrounded by the front-rear chamber and the tip chamber. The rear-end portion of the lower surface tether on the rear side of the seat is notched in a substantially arc shape. The airbag body is a seat-mounted airbag device configured to extend toward the front side of the seat including the lower surface tether when restraining the occupant's head.

2. The seat-mounted airbag device according to claim 1, wherein a maximum curvature portion at the rear-end portion of the lower surface tether on the rear side of the seat is located on the tip chamber side with respect to a virtual straight line along the longitudinal direction of the seat passing through the center of gravity of the occupant's head in plan view.

3. The seat-mounted airbag device according to claim 1 or claim 2, wherein the lower surface tether is a tether chamber that expands by a gas ejected from the inflator.

4. The airbag body has an upper surface tether that connects an intermediate portion in the deployment direction at the upper portion of the front-rear chamber and an intermediate portion in the deployment direction at the upper portion of the tip chamber and covers the upper portion of the space surrounded by the front-rear chamber and the tip chamber. The upper surface tether is a tether chamber that expands by a gas ejected from the inflator. The seat-mounted airbag device according to claim 3, wherein the airbag body is configured to extend toward the front side of the seat including the upper surface tether when restraining the occupant's head. According to claim 5, a gas ejected from an inflator actuated by detecting or predicting a collision of a vehicle expands from the side of the occupant's head through the front side of the seat, and includes a front-rear chamber disposed on the side of the occupant's head, and a tip chamber that expands from the front-side end of the front-rear chamber inward in the seat width direction and is disposed on the front side of the seat in front of the occupant's face, an upper tether connecting an intermediate portion in the deployment direction at the upper portion of the front-rear chamber and an intermediate portion in the deployment direction at the upper portion of the tip chamber, and a lower tether connecting an intermediate portion in the deployment direction at the lower portion of the front-rear chamber and an intermediate portion in the deployment direction at the lower portion of the tip chamber, and an airbag body having the same. The upper tether and the lower tether are formed of a material that extends more than the base fabric of the airbag body. The airbag body is a seat-mounted airbag device configured to extend toward the front side of the seat including the upper tether and the lower tether when restraining the occupant's head. According to claim 6, a gas ejected from an inflator actuated by detecting or predicting a collision of a vehicle expands from the side of the occupant's head through the front side of the seat, and includes a front-rear chamber disposed on the side of the occupant's head, and a tip chamber that expands from the front-side end of the front-rear chamber inward in the seat width direction and is disposed on the front side of the seat in front of the occupant's face, and a lower tether connecting an intermediate portion in the deployment direction at the lower portion of the front-rear chamber and an intermediate portion in the deployment direction at the lower portion of the tip chamber, and an airbag body having the same. The front-rear chamber is bent in the seat vertical direction or the seat width direction and has a connecting member that connects the front-side end and the rear-side end of the seat at the shortest distance. The airbag body is configured to extend toward the front side of the seat including the lower tether by the front-rear chamber whose bending is extended by the connecting member releasing the connection by a tensile load equal to or greater than a predetermined value acting when restraining the occupant's head, and is a seat-mounted airbag device. Claim 7: A seat-mounted airbag device comprising an airbag body having: a front-rear chamber that is deployed from a gas ejected from an inflator activated by detecting or predicting a collision of a vehicle, through the side of the occupant's head, to the front side of the seat; a tip chamber that is deployed from the front-side end of the front-rear chamber in the seat width direction inward, and is disposed on the front side of the seat in front of the occupant's face; and a lower tether that connects an intermediate portion in the deployment direction at the lower part of the front-rear chamber and an intermediate portion in the deployment direction at the lower part of the tip chamber. The front-rear chamber is constituted by a plurality of divided chambers arranged in the seat front-rear direction. The airbag body is configured to extend toward the front side of the seat including the lower tether when the divided chambers extend toward the front side of the seat when restraining the occupant's head. Claim 8: A seat-mounted airbag device comprising an airbag body having: a front-rear chamber that is deployed from a gas ejected from an inflator activated by detecting or predicting a collision of a vehicle, through the side of the occupant's head, to the front side of the seat; a tip chamber that is deployed from the front-side end of the front-rear chamber in the seat width direction inward, and is disposed on the front side of the seat in front of the occupant's face; and a lower tether that connects an intermediate portion in the deployment direction at the lower part of the front-rear chamber and an intermediate portion in the deployment direction at the lower part of the tip chamber. The front-rear chamber is formed in a bellows shape folded in the seat front-rear direction, and has a thread sewn to maintain the bellows shape. The airbag body is configured to extend toward the front side of the seat including the lower tether by the front-rear chamber whose bellows shape is extended by the thread being cut by a tensile load equal to or greater than a predetermined value acting when restraining the occupant's head. Claim 9: The seat-mounted airbag device according to any one of Claims 1 to 8, wherein a plurality of circular seam portions are formed side by side in the seat front-rear direction at least at the center in the seat vertical direction of the tip chamber. Claim 10: The seat-mounted airbag device according to any one of Claims 1 to 8, wherein a seam portion extending in the seat front-rear direction is formed at least at the center in the seat vertical direction of the tip chamber.

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