JP7707978B2 - Seat-mounted airbag device - Google Patents

Description

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

Side airbag devices that include an airbag main body that deploys forward from one side of the seat back and is positioned to the side of the occupant's upper body (including the head) during a diagonal front collision of the vehicle, and an airbag protrusion that deploys inward from the airbag main body in the seat width direction and is positioned in front of the occupant's face, with the two parts connected to each other by a planar tether, have been known for some time (see, for example, Patent Document 1).

JP 2006-008105 A

However, the above-mentioned side airbag device is configured to restrain only the head of the occupant, which moves diagonally forward, by using the airbag protrusion located in front of the occupant's face. Therefore, when the occupant's head is restrained, the amount of forward movement of the occupant's head may be smaller than the amount of forward movement of the occupant's chest, which is determined by the restraining force of the seat belt, and the occupant's neck may tilt backward (bend backward) more.

Therefore, the present invention aims to provide a seat-mounted airbag device that can prevent the occupant's neck from tilting backward when the occupant's head is restrained.

In order to achieve the above object, a seat-mounted airbag device of a first aspect of the present invention comprises an airbag body having: front and rear chambers that are positioned to the side of the occupant's head and that deploy through the side of the head of an occupant toward the front side of the seat by gas ejected from an inflator that is activated when a vehicle collision is detected or predicted; a tip chamber that deploys inward in the seat width direction from the front end of the front and rear chambers and is positioned on the front side of the occupant's face in the seat; an upper tether connecting a middle portion in the deployment direction at the upper end of the front and rear chambers to a middle portion in the deployment direction at the upper end of the tip chamber; and a lower tether connecting a middle portion in the deployment direction at the lower end of the front and rear chambers to a middle portion in the deployment direction at the lower end of the tip chamber, and the airbag body is configured to extend toward the front side of the seat, including at least the lower tether, when the occupant's head is restrained.

According to the first aspect of the invention, when a vehicle collision is detected or predicted, the inflator is activated to eject gas, and the front and rear chambers are deployed to the front side of the seat by passing the side of the occupant's head and disposed to the side of the occupant's head. The tip chamber is deployed from the front end of the front and rear chambers to the inside of the seat width direction and disposed to the front side of the occupant's face. Here, the airbag body has an upper tether that connects the middle part in the deployment direction at the upper end of the front and rear chambers to the middle part in the deployment direction at the upper end of the tip chamber, and a lower tether that connects the middle part in the deployment direction at the lower end of the front and rear chambers to the middle part in the deployment direction at the lower end of the tip chamber. The airbag body is configured to extend to the front side of the seat including at least the lower tether when the occupant's head is restrained. Therefore, when the occupant's head is restrained, the amount of movement of the occupant's head to the front side of the seat is suppressed from becoming smaller than the amount of movement of the occupant's chest to the front side of the seat, which is determined by the restraining force of the seat belt, and the backward tilt of the occupant's neck is suppressed.

A seat-mounted airbag device of a second aspect of the present invention is a seat-mounted airbag device of the first aspect , wherein the upper tether is an upper surface tether covering an upper portion of the space surrounded by the front and rear chambers and the tip chamber, and the lower tether is a lower surface tether covering a lower portion of the space surrounded by the front and rear chambers and the tip chamber, and the seat rear side end of the lower surface tether is cut out in an approximately arc shape.

According to the second aspect of the invention, the upper tether is an upper surface tether that covers the upper part of the space surrounded by the front and rear chambers 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 and rear chambers and the tip chamber. The seat rear end of the lower surface tether is cut out in a substantially arc shape. Therefore, compared to when the seat rear end of the lower surface tether is formed in a straight line, the line length of the lower surface tether at the seat rear end is longer, and the movement of the airbag body (particularly the tip chamber) toward the front side of the seat is less likely to be hindered. Therefore, when the occupant's head is restrained, the amount of movement of the occupant's head toward the front side of the seat is suppressed from becoming smaller, and the backward tilt of the occupant's neck is suppressed.

A seat-mounted airbag device of a third aspect of the present invention is a seat-mounted airbag device of the second aspect , wherein the maximum curvature portion at the seat rear end portion of the lower surface tether is located on the tip chamber side with respect to an imaginary straight line along the fore-and-aft direction of the seat that passes through the center of gravity of the occupant's head in a plan view.

According to the third aspect of the invention, the maximum curvature portion at the seat rear end of the lower surface tether is located on the tip chamber side of an imaginary line along the seat front-rear direction passing through the center of gravity of the occupant's head in a plan view. Therefore, compared to a case where the maximum curvature portion at the seat rear end of the lower surface tether is located on an imaginary line along the seat front-rear direction passing through the center of gravity of the occupant's head in a plan view, the amount of movement of the occupant's head toward the front side of the seat is more effectively prevented from becoming small when the occupant's head is restrained, and the tip of the tip chamber is more likely to bend toward the rear side of the seat. Therefore, even if the line length at the seat rear end of the lower surface tether is long, the occupant's head is prevented from slipping through the airbag body (particularly the tip chamber).

A fourth aspect of the seat-mounted airbag device according to the present invention is the seat-mounted airbag device of the second or third aspect , wherein the lower surface tether is a tether chamber that is deployed by gas ejected from the inflator.

According to the fourth aspect of the invention, the lower surface tether is a tether chamber that is deployed by gas ejected from the inflator. Therefore, even if the lower surface tether hits the occupant's neck when the occupant's head is restrained, the load on the occupant's neck caused by the lower surface tether is reduced compared to a case in which the lower surface tether is not a tether chamber that is deployed by gas ejected from the inflator.

A seat-mounted airbag device of a fifth aspect of the present invention is a seat-mounted airbag device of any one of the first to third aspects , wherein the upper tether and the lower tether are formed of a material that stretches more than a base fabric of the airbag body.

According to the fifth aspect of the invention, the upper tether and the lower tether are made of a material that stretches more than the base fabric of the airbag body. Therefore, when the occupant's head is restrained, the upper tether and the lower tether are stretched by the tensile load acting on the upper tether and the lower tether. Therefore, when the occupant's head is restrained, the amount of movement of the occupant's head toward the front of the seat is prevented from becoming small, and the occupant's neck is prevented from tilting backward.

A sixth aspect of the seat-mounted airbag device according to the present invention is a seat-mounted airbag device according to any one of the first to fifth aspects , in which a plurality of circular seam portions are formed in a row in the front-rear direction of the seat at least in the central portion of the tip chamber in the vertical direction of the seat.

According to the sixth aspect of the invention, a plurality of circular seams are formed in a row in the front-rear direction of the seat at least in the center of the tip chamber in the vertical direction of the seat. Therefore, the tip chamber is more likely to bend in the vertical direction of the seat than when a plurality of seams are formed in a row in the vertical direction of the seat. Therefore, when the head of the occupant is restrained, the amount of movement of the head toward the front of the seat is prevented from becoming small, and the backward tilt of the neck of the occupant is prevented.

A seventh aspect of the seat-mounted airbag device according to the present invention is a seat-mounted airbag device according to any one of the first to fifth aspects , wherein a seam portion extending in the front-rear direction of the seat is formed at least in the center of the tip chamber in the up-down direction of the seat.

According to the seventh aspect of the invention, a seam extending in the front-rear direction of the seat is formed at least in the center of the tip chamber in the vertical direction of the seat. Therefore, the tip chamber is more likely to bend in the vertical direction of the seat than when a seam extending in the vertical direction of the seat is formed. Therefore, when the head of the occupant is restrained, the amount of movement of the head toward the front of the seat is prevented from becoming small, and the backward tilt of the neck of the occupant is prevented.

A seat-mounted airbag device of an eighth aspect of the present invention is a seat-mounted airbag device of any one of the first to seventh aspects , wherein the front and rear chambers are formed to be bent in the vertical direction of the seat or the width direction of the seat and have a connecting member that connects the front end portion of the seat to the rear end portion of the seat over the shortest distance, and the connecting member is configured to release the connection when a tensile load of a predetermined value or more acts on the occupant's head when the occupant's head is restrained.

According to the eighth aspect of the invention, the front and rear chambers are bent in the seat vertical direction or the seat width direction, and the front end and rear end of the seat are connected by a connecting member at the shortest distance. The connecting member is configured to release the connection when a tensile load equal to or greater than a predetermined value acts when the occupant's head is restrained. In other words, the front and rear chambers extend toward the front of the seat when the connecting member is released. Therefore, when the occupant's head is restrained, the amount of movement of the occupant's head toward the front of the seat is prevented from becoming small, and the occupant's neck is prevented from tilting backward.

A ninth aspect of the seat-mounted airbag device according to the present invention is a seat-mounted airbag device according to any one of the first to seventh aspects , wherein the front and rear chambers are composed of a plurality of separate chambers arranged in the front-to-rear direction of the seat, and the separate chambers are configured to extend toward the front of the seat when the occupant's head is restrained.

According to the ninth aspect of the invention, the front-rear chamber is formed of a plurality of separate chambers aligned in the front-rear direction of the seat, and the separate chambers are configured to extend toward the front of the seat when the occupant's head is restrained. Therefore, when the occupant's head is restrained, the amount of movement of the occupant's head toward the front of the seat is suppressed from becoming small, and the backward tilt of the occupant's neck is suppressed.

A seat-mounted airbag device of a tenth aspect of the present invention is a seat-mounted airbag device of any one of the first to seventh aspects , wherein the front and rear chambers are formed into an accordion shape folded in the front-to-rear direction of the seat and are sewn with thread so as to maintain the accordion shape, and the thread is configured to break when a tensile load of a predetermined value or more acts on the occupant's head when the occupant's head is restrained.

According to the tenth aspect of the invention, the front and rear chambers are formed in an accordion shape folded in the front-rear direction of the seat, and are sewn with thread to maintain the accordion shape. The thread is configured to break when a tensile load equal to or greater than a predetermined value acts when the occupant's head is restrained. In other words, when the thread breaks, the front and rear chambers extend toward the front side of the seat. Therefore, when the occupant's head is restrained, the amount of movement of the occupant's head toward the front side of the seat is prevented from becoming small, and the backward tilt of the occupant's neck is prevented.

As described above, according to the present invention, a seat-mounted airbag device can prevent the occupant's neck from tilting backward when the occupant's head is restrained.

FIG. 2 is a side view showing a state after the seat-mounted airbag device according to the first embodiment has been deployed. FIG. 2 is a plan view showing a state after the seat-mounted airbag device according to the first embodiment has been deployed. 1 is an enlarged plan view, partially cut away, showing a seat-mounted airbag device according to a first embodiment in a pre-deployment state; FIG. 2 is an enlarged plan view showing the shape of a lower surface tether of the seat-mounted airbag device according to the first embodiment, with the upper surface tether omitted. 1A is a plan view showing a state before the head is restrained by the lower surface tether of the seat-mounted airbag device according to the first embodiment, and FIG. FIG. 11 is an enlarged plan view showing the shape of a lower surface tether of a seat-mounted airbag device according to a modified example of the first embodiment, with an upper surface tether omitted. 1A is a plan view showing a state before the head is restrained by the lower surface tether of the seat-mounted airbag device according to a modified example of the first embodiment, and FIG. 1B is a plan view showing a state after the head is restrained by the lower surface tether of the seat-mounted airbag device according to the modified example of the first embodiment. FIG. 11 is a development view showing an airbag body of the seat-mounted airbag device according to the second embodiment. FIG. 11 is a side view showing a state in which the head is restrained by the airbag body of the seat-mounted airbag device according to the second embodiment. FIG. 11 is a development view showing a modified example of the airbag body of the seat-mounted airbag device according to the second embodiment. 11A is a plan view showing a state before the head is restrained by the airbag body of the seat-mounted airbag device according to the third embodiment, FIG. 11B is a plan view showing a state during which the head is restrained by the airbag body of the seat-mounted airbag device according to the third embodiment, and FIG. 11C is a plan view showing a state after the head is restrained by the airbag body of the seat-mounted airbag device according to the third embodiment. 11A is a side view showing a state before the head is restrained by the airbag body of the seat-mounted airbag device according to the fourth embodiment, (B) is a side view showing a state during which the head is restrained by the airbag body of the seat-mounted airbag device according to the fourth embodiment, and (C) is a side view showing a state after the head is restrained by the airbag body of the seat-mounted airbag device according to the fourth embodiment. 13A is a plan view showing a state before the head is restrained by the airbag body of the seat-mounted airbag device according to the fourth embodiment, FIG. 13B is a plan view showing a state during which the head is restrained by the airbag body of the seat-mounted airbag device according to the fourth embodiment, and FIG. 13C is a plan view showing a state after the head is restrained by the airbag body of the seat-mounted airbag device according to the fourth embodiment. 13A and 13B are plan views showing a state before and after a head is restrained by an airbag body of the seat-mounted airbag device according to the fifth embodiment; 13A and 13B are plan views showing the seat-mounted airbag device according to the sixth embodiment before and after the head is restrained by the airbag body, respectively. FIG. 13 is a side view showing a state before the head is restrained by the airbag body of the seat-mounted airbag device relating to the sixth embodiment.

The following is a detailed description of an embodiment of the present invention with reference to the drawings. For ease of explanation, the arrow UP shown in each drawing indicates the seat upward direction, the arrow FR indicates the seat forward direction, and the arrow RH indicates the seat right direction. Therefore, in the following description, when the directions such as up/down, front/rear, and left/right are mentioned without special mention, they refer to the up/down, front/rear, and left/right directions of the vehicle seat. Furthermore, the left/right direction is synonymous with the seat width direction.

As shown in Figures 1 to 3, the seat-mounted airbag device (hereinafter simply referred to as the "airbag device") 30 according to this 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 this embodiment is described as being for the rear seat, this airbag device 30 may also be provided in the front seat.

As an example, the rear seat is the rear seat on the left side window 18 (see FIG. 3), and as described below, the airbag body 32 is deployed by passing between the head Ph of the occupant P on the side window 18 side and the head of the occupant (not shown) in the center seat. However, the airbag body 32 may be configured to deploy by passing between the side window 18 and the head Ph of the occupant P. As an example, the "occupant P" in this embodiment is an occupant equivalent to AM50 (50th percentile of American adult males) of the WorldSID (World Side Impact Dummy).

First Embodiment
First, an airbag device 30 according to a first embodiment will be described. As shown in Fig. 1 and Fig. 2, a vehicle seat 10 includes a seat cushion 12 on which an occupant P sits (supporting the buttocks and thighs of the occupant P), a seat back 14 that supports the back of the occupant P, and a headrest 16 that supports the head Ph of the occupant P.

As shown in FIG. 3, the headrest 16 has a block-shaped main body 16A that is movable up and down in the center of the seat width direction at the upper end of the seat back 14. More specifically, a pair of cylindrical headrest stays (not shown) are provided on the left and right sides in the center of the seat width direction on the underside of the main body 16A.

Each headrest stay is inserted into a pair of generally cylindrical headrest supports 26 provided on the left and right sides at the center in the seat width direction at the upper end of the seat back 14 so as to be movable up and down and fixable at a plurality of predetermined positions. This makes it possible to adjust the height position of the headrest 16 to match the position of the head Ph of the occupant P. The headrest 16 has a case portion 20 provided continuously from the rear of the main body portion 16A to both the left and right sides.

The case portion 20 is formed in a generally U-shape with an open front side in a plan view. The main body portion 16A of the headrest 16 is disposed inside the case portion 20 with almost no gaps. In the case portion 20, the front end faces (outer surfaces of the front wall 20F) of the left and right side portions 24 extending in the front-rear direction are generally flush with the front surface of the main body portion 16A.

In addition, the left and right (side portions 24) outer walls 20A and the rear wall 20B of the case portion 20 are made of resin cover members 22 formed in a generally U-shape in plan view. The upper wall 20U (see Figs. 1 and 2), lower wall (not shown), front wall 20F, and inner wall 20C facing the main body portion 16A of the case portion 20 are made of urethane foam (not shown) of a predetermined thickness, and the outer surfaces of the cover members 22 and the urethane foam are integrally covered with a skin material 21.

A predetermined space S (including a storage section S1 and a placement section S2, described later) is formed inside the case section 20. The airbag body 32 of the airbag device 30 is stored in the storage section S1, which is formed in the side section 24R on the opposite side of the case section 20 from the side window 18 (the right side, which is the center seat side in the illustrated example). The configuration of the airbag body 32 will be described in detail later.

The inflator 28 is disposed in the arrangement section S2, which is the rear side of the space S formed in the case section 20. The inflator 28 is formed in a generally cylindrical shape with a bottom, and its outer periphery is supported by a reaction plate (not shown) formed in a housing shape via a retainer (not shown) so that its axial center is disposed along the seat width direction.

The reaction plate is fixed to the seat back frame (not shown), for example, via a bracket (not shown), and is configured to receive the reaction force transmitted from the airbag body 32 deploying forward via the inflator 28. The reaction plate and the retainer are also arranged in the arrangement section S2.

The inflator 28 is electrically connected to an airbag ECU (not shown) installed in the vehicle, and a detection device (not shown) such as an acceleration sensor installed in the vehicle is electrically connected to the airbag ECU. Therefore, when a vehicle collision is detected by the detection device, the inflator 28 is activated via the airbag ECU and instantly ejects gas.

The inflator 28 may be configured to activate not only when a vehicle collision is detected, but also when a vehicle collision is predicted by a collision prediction sensor or the like (not shown). The connection part 31 of the airbag body 32 is fitted and connected to the outlet of the inflator 28.

As shown in Figures 1 and 2, the airbag device 30 has an airbag body 32 that deploys from the rear side (specifically, the rear right side) of the head Ph of an occupant P seated in the vehicle seat 10 to the front side when gas is ejected from an inflator 28 (see Figure 3).

The airbag body 32 has a front-rear chamber 34 that extends forward through the right side of the occupant P's head Ph and is positioned to the right side of the occupant P's head Ph (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), and a front end chamber 36 that extends inward in the seat width direction from the front end of the front-rear chamber 34 and is positioned in front of the occupant P's face and to the left side of the occupant P's head Ph. In other words, the airbag body 32 is bent into a roughly "J" shape when viewed from the bottom, so that it can restrain at least the head Ph of the occupant P.

2, the airbag body 32 has an upper tether 37 that connects the middle portion 34U in the deployment direction at the upper end of the front and rear chambers 34 and the middle 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 middle portion 34D in the deployment direction at the lower end of the front and rear chambers 34 and the middle portion 36D in the deployment direction at the lower end of the tip chamber 36.

More specifically, the upper tether 37 is a tether chamber that deploys when the airbag body 32 is inflated and deployed by the gas ejected from the inflator 28. As shown in FIG. 2, in plan view, the upper tether 37 has a rear edge 37A that connects the middle portion 34U in the deployment direction at the top end of the front and rear chambers 34 and the middle portion 36U in the deployment direction at the top 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 and rear chambers 34 and the tip chamber 36.

The peripheral edge of the upper surface tether 37B, excluding its rear edge 37A (rear end), is attached by sewing to the upper end of the front and rear chambers 34 and the upper end of the tip chamber 36, from the middle part 34U in the deployment direction at the upper end of the front and rear chambers 34 to the middle part 36U in the deployment direction at the upper end of the tip chamber 36.

Similarly, the lower tether 38 is a tether chamber that deploys together with the airbag body 32 when it is inflated and deployed by the gas ejected from the inflator 28. As shown in FIG. 4, in plan view, the lower tether 38 has a rear edge 38A that connects the middle portion 34D in the deployment direction at the lower end of the front and rear chambers 34 and the middle 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 portion of the space surrounded by the front and rear chambers 34 and the tip chamber 36.

The peripheral edge of the lower surface tether 38B, excluding the rear edge 38A (rear end), is attached by sewing to the lower end of the front and rear chambers 34 and the lower end of the tip chamber 36 from the middle part 34D in the deployment direction at the lower end of the front and rear chambers 34 to the middle part 36D in the deployment direction at the lower end of the tip chamber 36.

The airbag body 32 is configured to extend forward, including at least the lower surface tether 38B (lower tether 38), when the head of the occupant P is restrained. That is, as shown in FIG. 4, the rear end edge 38A of the lower surface tether 38B (lower tether 38) is largely cut out in an approximately arc shape (a mountain shape having a curve) between the middle part 34D of the front and rear chambers 34 in the deployment direction and the middle part 36D of the tip chamber 36 in the deployment direction, and is configured so that the line length is longer than when the middle part 34D of the front and rear chambers 34 and the middle part 36D of the tip chamber 36 are connected in a straight line (shown by the imaginary straight line K).

As a result, as shown in FIG. 5, when the head of the occupant P is restrained, the tip chamber 36 extends forward without being hindered by the lower surface tether 38B, and the tip of the tip chamber 36 bends rearward from the starting point T1 (see FIG. 4), making it possible to restrain the left side of the head Ph of the occupant P. Note that the starting point T1 here refers to the intersection of an imaginary straight line K1 drawn in a straight line from the middle part 34D of the front and rear chambers 34 in the deployment direction along the rear edge part 38A in a plan view, and the sewn part of the lower surface tether 38B in the tip chamber 36.

The shape of the rear end edge 38A of the lower surface tether 38B is not limited to the shape shown in Figure 5. As shown in Figure 6, it is preferable that the rear end edge 38A of the lower surface tether 38B is cut into 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 of the tip chamber 36) with respect to an imaginary straight line Kc along the fore-and-aft direction that passes through the center of gravity of the head Ph of the occupant P in a plan view (bottom view).

As a result, as shown in Figure 7, when the head of the occupant P is restrained, the tip chamber 36 extends further forward than in Figures 4 and 5 without being hindered by the lower surface tether 38B, and the tip of the tip chamber 36 bends rearward from the starting point T2 (see Figure 6), making it possible to restrain the left side of the head Ph of the occupant P. Note that the starting point T2 here refers to the intersection of an imaginary straight line K2 drawn in a straight line from the middle part 34D of the front and rear chambers 34 in the deployment direction along the rear end edge 38A in a plan view, and the sewn part of the lower surface tether 38B in the tip chamber 36.

As shown in FIG. 3, the airbag body 32 is wound outward in a roll with the vertical axis (in a plan view, with the roll-shaped outwardly wound portion 32A on the outer side in the seat width direction) and is stored in a storage portion S1 formed in the side portion 24R. A bellows portion 32B is formed on the upstream side of the outwardly wound portion 32A in the deployment direction, so as to be continuous with the outwardly wound portion 32A.

That is, the airbag body 32 is stored in the storage section S1 with the bellows portion 32B, which is folded like a bellows and continues from the outer roll-up portion 32A upstream in the deployment direction. Therefore, when the airbag body 32 is deployed forward from the side portion 24R through the right side of the head Ph of the occupant P by the gas ejected from the inflator 28, the bellows portion 32B first unravels and deploys, and then the outer roll-up portion 32A unravels and deploys.

Note that, in FIG. 3, the bellows portion 32B is formed in only two sets, with each folded portion being considered as one set, but this is not limited to this. It is sufficient that multiple sets of the bellows portion 32B are formed, and three or more sets may be formed.

The front wall 20F that constitutes the front end surface of the side portion 24R is broken, for example, in a straight line along the up-down direction when viewed from the front, together with a part of the front wall 20F side of the upper wall 20U, as the airbag body 32 deploys. The broken part is preferably the seat width direction inner end 20N of the front wall 20F.

If the location of the break is the inner end 20N of the front wall 20F in the seat width direction (for example, if the inner end 20N of the front wall 20F in the seat width direction has a weak part that is easily broken), the front wall 20F will be opened with the outer end 20T in the seat width direction as a hinge part.

The operation of the airbag device 30 according to the first embodiment, which is configured as described above, will now be described.

When the detection device detects that the vehicle has experienced a frontal collision, the inflator 28 is activated and instantly ejects gas into the airbag body 32. When gas is ejected into the airbag body 32, the airbag body 32 expands (by being pressed from the inside by the airbag body 32), causing the front wall 20F of the side portion 24R to break together with a portion of the front wall 20F side of the upper wall 20U.

The airbag body 32 then deploys forward from the side portion 24R through the right side of the head Ph of the occupant P (the gap between the head Ph of the occupant P on the side window 18 side and the head of the occupant in the center seat). That is, the airbag body 32 first deploys as the bellows portion 32B, which is folded in a bellows shape, unravels, and then the outer rolled portion 32A, which is wound outwardly in a roll, unravels.

It is generally known that a bellows-shaped structure unravels more quickly than a rolled structure (the resistance to deployment is smaller when the bellows-shaped structure is deployed than when the rolled structure is deployed). Therefore, compared to an airbag body 32 that only has an outer rolled portion 32A, an airbag body 32 that has an outer rolled portion 32A and an bellows portion 32B in that order from the downstream side in the deployment direction can deploy forward more quickly.

When the front and rear chambers 34 are inflated and positioned to the right of the head Ph of the occupant P, gas flows from the front end of the front and rear chambers 34 into the tip chamber 36, causing the tip chamber 36 to inflate and deploy inward in the seat width direction. Gas also flows into the upper surface tether 37B and the lower surface tether 38B, causing the upper surface tether 37B and the lower surface tether 38B to inflate and deploy.

In this way, at least the head Ph of the occupant P seated in the vehicle seat 10 is restrained by the fully deployed airbag body 32 (front and rear chambers 34 and tip chamber 36). In other words, the airbag body 32 (front and rear chambers 34 and tip chamber 36) can prevent at least the head Ph of the occupant P from moving forward due to inertial force.

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

Therefore, compared to when the rear end edge 38A of the lower surface tether 38B is formed in a straight line, the line length at the rear end edge 38A of the lower surface tether 38B is longer, and the lower surface tether 38B is less likely to (or does not) hinder the airbag body 32 (particularly the tip chamber 36) from extending forward.

As a result, when the head of the occupant P is restrained, the forward movement of the head Ph of the occupant P can be prevented from becoming smaller (reduced stroke amount) relative to the forward movement of the chest of the occupant P, which is determined by the restraining force of the seat belt (not shown), and the backward tilt (backward bending) of the neck of the occupant P caused by the airbag body 32 (particularly the tip chamber 36) not stretching forward can be prevented. Furthermore, because the rear end edge 38A of the lower surface tether 38B is largely cut out in a substantially arc shape, even if it is located at the neck of the occupant P (even if it hits the neck of the occupant P), the load on the neck of the occupant P caused by the lower surface tether 38B can be reduced.

As described above, it is preferable that the rear end edge 38A of the lower surface tether 38B is cut out in such a shape that the maximum curvature portion 40 is located on the tip chamber 36 side with respect to the imaginary line Kc along the front-rear direction passing through the center of gravity of the head Ph of the occupant P in a plan view (bottom view). This makes it possible to more effectively prevent the amount of forward movement of the head Ph of the occupant P from becoming small when the head of the occupant P is restrained, and makes it easier for the tip of the tip chamber 36 to bend toward the rear side, compared to when the maximum curvature portion of the rear end edge 38A of the lower surface tether 38B is located on the imaginary line Kc passing through the center of gravity of the head Ph of the occupant P in a plan view (bottom view). Therefore, even if the line length of the rear end edge 38A of the lower surface tether 38B is long, it is possible to prevent the head Ph of the occupant P from slipping through the airbag main body 32 (particularly the tip chamber 36).

The lower surface tether 38B is also a tether chamber that is deployed by the gas ejected from the inflator 28. Therefore, even if the lower surface tether 38B interferes with (hits) the neck of the occupant P when the head of the occupant P is restrained, the load on the neck of the occupant P caused by the lower surface tether 38B can be more effectively reduced than if the lower surface tether 38B was not a tether chamber that is deployed by the gas ejected from the inflator. Furthermore, since the upper tether 37 (upper surface tether 37B) is located above the head Ph of the occupant P, it does not interfere with (hit) the head Ph of the occupant P.

As described above, the airbag body 32 deploys forward as the outwardly wound portion 32A unwinds. Therefore, there is no risk of the face of the occupant P being injured by the airbag body 32 when the airbag body 32 deploys. Furthermore, if the front wall 20F is configured to open with the seat width direction outer end 20T as a hinge when the airbag body 32 deploys, the airbag body 32 can prevent the deploying front wall 20F from contacting the head Ph of the occupant P.

Second Embodiment
Next, an airbag device 30 according to a second embodiment will be described. Note that the same reference numerals are used to designate the same parts as those in the first embodiment, and detailed descriptions thereof (including common functions) will be omitted as appropriate.

As shown in FIG. 8, the airbag body 32 of the airbag device 30 according to the second embodiment differs from the first embodiment only in that multiple (e.g., a pair of two) circular seam portions 42 are formed side by side in the front-rear direction at least in the vertical center of the tip chamber 36.

In this way, when multiple circular seam portions 42 are formed in a row in the front-rear direction in the vertical center of the tip chamber 36, as shown in FIG. 9, the tip chamber 36 is more likely to deform so as to bend in the vertical direction. In other words, the tip chamber 36 is more likely to deform into a curved shape that is convex forward in side view than when multiple seam portions 42 are formed in a row in the vertical direction. Therefore, when the head of the occupant P is restrained, a reduction in the amount of forward stroke of the head Ph of the occupant P can be suppressed, and the backward tilt of the neck of the occupant P can be effectively suppressed.

Instead of the seam portion 42, a seam portion 44 extending in the front-rear direction may be formed in the vertical center of the tip chamber 36 as shown in FIG. 10. In this case, the same effect 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, so that when the head of the occupant P is restrained, the reduction in the amount of forward stroke of the head Ph of the occupant P can be suppressed, and the backward tilt of the neck of the occupant P can be effectively suppressed.

Third Embodiment
Next, an airbag device 30 according to a third embodiment will be described. Note that the same reference numerals are used to designate the same parts as those in the first embodiment, and detailed descriptions thereof (including common functions) will be omitted as appropriate.

As shown in FIG. 11, the airbag body 32 of the airbag device 30 according to the third embodiment differs from the first embodiment only in that the upper tether 37 and the lower tether 38 are not tether chambers that are deployed by the gas ejected from the inflator 28, but are made of a material that stretches more than the base fabric of the airbag body 32, for example, rubber-like upper surface tether 37C and lower surface tether 38C that have a predetermined thickness.

The upper surface tether 37C and the lower surface tether 38C configured in this manner are capable of extending in the direction in which the tip chamber 36 moves away from the front and rear chambers 34. Therefore, when the head of the occupant P is restrained, the tensile load acting on the upper surface tether 37C and the lower surface tether 38C causes the upper surface tether 37C and the lower surface tether 38C to extend in the above-mentioned direction of separation. Therefore, when the head of the occupant P is restrained, it is possible to suppress a reduction in the amount of stroke of the head Ph of the occupant P toward the forward direction, and it is possible to effectively suppress the backward tilt of the neck of the occupant P.

Fourth Embodiment
Next, an airbag device 30 according to a fourth embodiment will be described. Note that the same reference numerals are used to designate the same parts as those in the first embodiment, and detailed descriptions thereof (including common functions) will be omitted as appropriate.

As shown in FIG. 12, the airbag body 32 of the airbag device 30 according to the fourth embodiment has front and rear chambers 34 bent in the vertical direction, a connecting member 46 that connects the front end 34F and the rear end 34B at the shortest distance, and the connecting member 46 is configured to break (release the connection) when a tensile load equal to or greater than a predetermined value acts on the head of the occupant P.

More specifically, the front-rear chamber 34 is divided into upper and lower parts, except for the front end 34F and the rear end 34B, and the upper chamber 34A of the front-rear chamber 34 is bent upward in a generally "Λ" shape, and the lower chamber 34C of the front-rear chamber 34 is bent downward in a generally "V" shape.

The vertical center of the front end 34F of the front and rear chambers 34 and the vertical center of the rear end 34B are connected by a connecting member 46 at the shortest distance. A bracket 47 is provided on the illustrated rear end 34B, and the connecting member 46 is attached to the rear end 34B via the bracket 47.

The connecting member 46 is made of a string-like material such as thread, and is set to break when a tensile load equal to or exceeds a predetermined value that acts when the head of the occupant P is restrained. Therefore, during a frontal collision of the vehicle, the head Ph of the occupant P moves forward due to inertial force, pushing the airbag body 32 forward and moving it, and when the tensile load reaches a predetermined value, the connecting member 46 breaks.

As a result, the upper chamber 34A and the lower chamber 34C of the bent front-rear chamber 34 extend forward, preventing a reduction in the amount of forward stroke of the head Ph of the occupant P. Therefore, when the head of the occupant P is restrained, the backward tilt of the neck of the occupant P can be effectively prevented.

13, the airbag body 32 of the airbag device 30 according to the fourth embodiment may have the front and rear chambers 34 bent outward in the seat width direction in a generally "Λ" shape in plan view, and the front upper end of the front and rear chambers 34 below the upper tether 37 and the rear upper end of the front and rear chambers 34 (brackets 47 provided at the rear upper end of the front and rear chambers 34) may be connected by a connecting member 46 at the shortest distance. In this case, the connecting member 46 breaks when a tensile load equal to or greater than a predetermined value acts on the head of the occupant P when the head of the occupant P is restrained, and the same effect as above can be obtained.

Fifth Embodiment
Next, an airbag device 30 according to a fifth embodiment will be described. Note that the same reference numerals are used to designate the same parts as those in the first embodiment, and detailed descriptions thereof (including common functions) will be omitted as appropriate.

As shown in FIG. 14, the airbag body 32 of the airbag device 30 according to the fifth embodiment differs from the first embodiment only in that the front and rear chambers 34 are composed of multiple separate chambers 35 that are connected to each other and aligned in the front-rear direction so that gas can flow through them, and each separate chamber 35 is configured to extend forward when the head of the occupant P is restrained.

Each divided chamber 35 is formed in a generally spherical shape with equal vertical and front-to-rear lengths, and is configured to be extendable forward. Therefore, during a frontal collision of the vehicle, the head Ph of the occupant P moves forward due to inertial force, pushing and moving the airbag body 32 forward, and pulling the front and rear chambers 34 forward, causing each divided chamber 35 to extend forward.

This makes it possible to prevent a reduction in the amount of forward stroke of the head Ph of the occupant P, and therefore effectively prevents the neck of the occupant P from tilting backward when the head of the occupant P is restrained. Each divided chamber 35 may be formed in a generally cylindrical shape with the vertical direction as the longitudinal direction (axial direction).

Sixth Embodiment
Finally, an airbag device 30 according to a sixth embodiment will be described. Note that the same reference numerals are used to designate the same parts as those in the first embodiment, and detailed descriptions thereof (including common functions) will be omitted as appropriate.

As shown in Figures 15(A) and 16, the airbag body 32 of the airbag device 30 according to the sixth embodiment is configured such that at least a portion of the front and rear chambers 34 on the case portion 20 side is folded in a bellows shape in the front-rear direction to form a bellows portion 34J, and is sewn with thread 48 to maintain the bellows shape, and the thread 48 is configured to break when a tensile load of a predetermined value or more acts on the bellows portion 34J when the head of the occupant P is restrained. The only difference from the first embodiment is that the airbag body 32 is configured such that at least a portion of the front and rear chambers 34 on the case portion 20 side is folded in a bellows shape in the front-rear direction to form a bellows portion 34J.

More specifically, the front-rear chamber 34 is divided into two regions, the front and rear, and the front region is a normal chamber, while the rear region is a bellows portion 34J that is folded like a bellows, as shown in FIG. 16. A communication passage 50 made of a flexible tube or the like for passing gas is provided in the vertical center of the bellows portion 34J. In other words, the bellows portion 34J of the front-rear chamber 34 is folded along multiple fold lines that run vertically above and below the communication passage 50, and the folded and overlapping portions are sewn vertically with thread 48.

With the front and rear chambers 34 configured in this way, when gas is ejected from the inflator 28 during a frontal collision of the vehicle, the gas flows through the communication passages 50 to the front region of the front and rear chambers 34, inflating and deploying the front region of the front and rear chambers 34. Then, as gas flows from the front region of the front and rear chambers 34 into the tip chamber 36, the tip chamber 36 inflates and deploys, and the airbag body 32 restrains the head Ph of the occupant P, which tends to move forward due to inertial force.

Then, the head Ph of the occupant P, which moves forward due to the inertial force, presses the airbag body 32 forward, and pulls the front and rear chambers 34 forward. In other words, a tensile load toward the front is applied to the bellows portion 34J, which is the rear region of the front and rear chambers 34. When the tensile load reaches or exceeds a predetermined value, the thread 48 breaks.

As a result, the bellows-like folded portion of the bellows portion 34J unfolds, and as shown in FIG. 15(B), the rear area of the front and rear chambers 34 extends forward together with the communication passage 50. This makes it possible to suppress a reduction in the forward stroke amount of the head Ph of the occupant P, and effectively suppresses the backward tilt of the neck of the occupant P when the head of the occupant P is restrained.

The seat-mounted airbag device 30 according to this embodiment has been described above with reference to the drawings, but the seat-mounted airbag device 30 according to this embodiment is not limited to the one shown in the drawings, and the design can be modified as appropriate without departing from the scope of the present invention. For example, the seat-mounted airbag device 30 according to this embodiment may be a combination of the configurations of each embodiment as appropriate.

Furthermore, the upper tether 37 and the lower tether 38 are not limited to the upper surface tether 37B and the lower surface tether 38B, and may be, for example (not shown), a band-shaped tether whose front end (front edge) is sized not to reach the upper end and lower end 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. Furthermore, in the second embodiment, the seam portion 42 and the seam portion 44 formed in the vertical center of the tip chamber 36 may also be formed in the front end portions of the front and rear chambers 34, respectively.

In addition, in the fourth embodiment, the connecting member 46 may be configured to be detached from, for example, a bracket 47 provided at the rear end 34B (including the rear upper end shown in FIG. 13) of the front-rear chamber 34, rather than being broken by a tensile load of a predetermined value or more acting when the head of the occupant P is restrained. In this way, the connecting member 46 only needs to be configured to be released from the connection by a tensile load of a predetermined value or more acting when the head of the occupant P is restrained.

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 side 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 (10)

an airbag body including: front and rear chambers that are deployed to the front side of a seat by gas ejected from an inflator that is activated when a vehicle collision is detected or predicted, passing through the sides of the head of an occupant and being disposed on the side of the head of the occupant; a tip chamber that is deployed inward in the seat width direction from the front end of the front and rear chambers and is disposed on the front side of the face of the occupant ; and a lower surface tether that connects a middle portion in the deployment direction at a lower portion of the front and rear chambers to a middle portion in the deployment direction at a lower portion of the tip chamber and covers a lower portion of a space surrounded by the front and rear chambers and the tip chamber;
The seat rear end of the lower surface tether is cut out in a substantially arc shape,
The airbag body is configured to extend toward the front side of the seat, including the lower surface tether , when the occupant's head is restrained. 2. The seat-mounted airbag device according to claim 1 , wherein the maximum curvature portion at the seat rear end portion of the lower surface tether is located on the tip chamber side with respect to an imaginary line extending in the front-to-rear direction of the seat that passes through the center of gravity of the occupant's head in a plan view. 3. The seat-mounted airbag device according to claim 1 , wherein the lower surface tether is a tether chamber that is inflated by gas ejected from the inflator . the airbag body has an upper surface tether that connects an intermediate portion in the deployment direction at an upper portion of the front and rear chambers and an intermediate portion in the deployment direction at an upper portion of the tip chamber and covers an upper portion of a space surrounded by the front and rear chambers and the tip chamber,
The upper surface tether is a tether chamber that is deployed by gas ejected from the inflator ,
4. 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 the head of the occupant is restrained. an airbag body having: front and rear chambers that are deployed to the front side of a seat by gas ejected from an inflator that is activated when a vehicle collision is detected or predicted, passing through the side of the head of an occupant and being disposed on the side of the head of the occupant; a tip chamber that is deployed inward in the seat width direction from the front end of the front and rear chambers and is disposed on the front side of the face of the occupant; an upper tether that connects an intermediate portion in the deployment direction at an upper part of the front and rear chambers to an intermediate portion in the deployment direction at an upper part of the tip chamber; and a lower tether that connects an intermediate portion in the deployment direction at a lower part of the front and rear chambers to an intermediate portion in the deployment direction at a lower part of the tip chamber;
The upper tether and the lower tether are formed of a material that stretches more than a base fabric of the airbag body ,
The airbag body is configured to extend toward the front side of the seat, including the upper tether and the lower tether, when the head of the occupant is restrained . an airbag body including: front and rear chambers that are deployed to the front side of a seat by gas ejected from an inflator that is activated when a vehicle collision is detected or predicted, passing through the sides of an occupant's head; a tip chamber that is deployed inward in the seat width direction from the front end of the front and rear chambers and is positioned on the front side of the occupant's face; and a lower tether that connects a middle portion of a lower portion of the front and rear chambers in the deployment direction to a middle portion of a lower portion of the tip chamber in the deployment direction,
The front and rear chambers are bent in the seat up-down direction or the seat width direction, and have a connecting member that connects the seat front end and the seat rear end at the shortest distance,
The airbag body extends toward the front side of the seat, including the lower tether, by the front and rear chambers which are straightened when the connecting member is released due to a tensile load of a predetermined value or more acting when the occupant's head is restrained . an airbag body including: front and rear chambers that are deployed to the front side of a seat by gas ejected from an inflator that is activated when a vehicle collision is detected or predicted, passing through the sides of an occupant's head; a tip chamber that is deployed inward in the seat width direction from the front end of the front and rear chambers and is positioned on the front side of the occupant's face; and a lower tether that connects a middle portion of a lower portion of the front and rear chambers in the deployment direction to a middle portion of a lower portion of the tip chamber in the deployment direction,
The front and rear chambers are configured by a plurality of separate chambers arranged in the front-rear direction of the seat,
The airbag body extends toward the front side of the seat, including the lower tether, when the head of the occupant is restrained by the divided chamber extending toward the front side of the seat . an airbag body including: front and rear chambers that are deployed to the front side of a seat by gas ejected from an inflator that is activated when a vehicle collision is detected or predicted, passing through the sides of an occupant's head; a tip chamber that is deployed inward in the seat width direction from the front end of the front and rear chambers and is positioned on the front side of the occupant's face; and a lower tether that connects a middle portion of a lower portion of the front and rear chambers in the deployment direction to a middle portion of a lower portion of the tip chamber in the deployment direction,
The front and rear chambers are formed in a bellows shape folded in the front and rear direction of the seat, and have threads sewn therein 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 and rear chambers whose accordion-like shape is stretched by the thread breaking due to a tensile load of a predetermined value or more acting when the occupant's head is restrained . 9. The seat-mounted airbag device according to claim 1 , wherein a plurality of circular seams are formed in at least a central portion of the tip chamber in the up-down direction of the seat, the seams being aligned in the front-rear direction of the seat. 9. The seat-mounted airbag device according to claim 1 , wherein a seam extending in a front-rear direction of the seat is formed at least in a central portion of the tip chamber in the up-down direction of the seat .