Seat-mounted airbag device

Abstract

The present disclosure provides a seat-mounted airbag device. The seat-mounted airbag device includes an airbag main body having a front-and-rear chamber and a top-end chamber. The front-and-rear chamber is deployed from the side of a passenger's head by gas injected from an inflator that operates in response to detection or prediction of a vehicle collision, and is disposed at the side of the passenger's head. The top-end chamber is deployed toward the inside in the seat width direction from the seat front side end of the front-and-rear chamber, and is disposed at the seat front side of the passenger's face. The airbag main body is housed in a state of having an outer roll portion that is rolled outward into a roll shape with the seat up-and-down direction as an axis, after being folded back at the top end of the top-end chamber to the opposite side of the passenger side.

Description

TECHNICAL FIELD

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

[0002] Hitherto, a side airbag device has been known, which has a main airbag body portion that deploys from one side of a seat back toward the front when a collision from the oblique front of a vehicle occurs and is disposed at the side of the upper body (including the head) of an occupant, and an airbag protruding portion that deploys from the main airbag body portion toward the inside in the seat width direction and is disposed at the front of the face of the occupant, and connects the both to each other by a planar tether (for example, refer to Japanese Patent Application Publication No. 2006-008105). SUMMARY

[0003] However, in a one-side deployment seat-mounted airbag device that deploys from the rear of the head of an occupant and is disposed at the front of the face, there is a concern that, during the head restraint process in the latter half of the collision, the airbag body rotates with its rear-side fixed point as the center in a direction away from the head of the occupant when viewed from above, so that the head of the occupant comes out of the airbag body. As a countermeasure to this concern, a structure is considered in which the apex chamber (corresponding to the airbag protruding portion described above) of the airbag body is disposed at an acute angle with respect to the front-rear chamber (corresponding to the main airbag body portion described above) of the airbag body when viewed from above, to give the airbag body a counteracting moment.

[0004] However, in such an airbag body, if gas flows to the apex chamber at an early timing during the deployment of the front-rear chamber, the apex chamber interferes with (hits) the head of the occupant (the face) before the front side of the head, so that there is a high possibility that the airbag body becomes unable to deploy as planned. Thus, in a structure in which the airbag body of a seat-mounted airbag device deploys as planned, there is room for improvement.

[0005] Therefore, an object of the present disclosure is to obtain a seat-mounted airbag device that can deploy an airbag body as planned.

[0006] Method for solving the problem

[0007] To achieve the above object, a seat-mounted airbag device according to a first aspect of the present disclosure includes an airbag main body having a front-rear chamber and a top-end chamber. The front-rear chamber is deployed from a side of a head of an occupant to a seat front side by a gas injected from an inflator that operates in response to detection or prediction of a vehicle collision, and is disposed at the side of the head of the occupant. The top-end chamber is deployed from a seat front side end portion of the front-rear chamber to an inside in a seat width direction, and is disposed at a seat front side of a face of the occupant. The airbag main body is folded back at a top end portion of the top-end chamber to an opposite side to the occupant side, and is housed in a state of having an outer folded portion folded outward in a roll shape with the seat up-down direction as an axis.

[0008] According to the first aspect, when the vehicle collision is detected or predicted, the inflator operates to inject the gas, so that the front-rear chamber is deployed from the side of the head of the occupant to the seat front side and is disposed at the side of the head of the occupant, and the top-end chamber is deployed from the seat front side end portion of the front-rear chamber to the inside in the seat width direction and is disposed at the seat front side of the face of the occupant. Here, since the airbag main body is folded back at the top end portion of the top-end chamber to the opposite side to the occupant side and is housed in the roll shape with the seat up-down direction as the axis, when the gas is injected from the inflator, the outer folded portion folded in the roll shape is unfolded and deployed, so that the front-rear chamber is disposed at the side of the head of the occupant. Also, although the top-end chamber is deployed from the seat front side end portion of the front-rear chamber to the inside in the seat width direction thereafter, since the top end portion of the top-end chamber is folded back to the opposite side to the occupant side, the top end portion thereof is deployed latest. Therefore, the top-end chamber is prevented from interfering with (hitting) the head of the occupant before being disposed at the seat front side of the face of the occupant, so that the airbag main body is deployed as planned.

[0009] Further, a seat-mounted airbag device according to a second aspect includes the seat-mounted airbag device according to the first aspect. The airbag main body has an upper tether that links an expansion direction intermediate portion in an upper end portion of the top-end chamber and an expansion direction intermediate portion in an upper end portion of the front-rear chamber, and a lower tether that links an expansion direction intermediate portion in a lower end portion of the top-end chamber and an expansion direction intermediate portion in a lower end portion of the front-rear chamber. The top end portion of the top-end chamber is folded back along an imaginary straight line that connects the expansion direction intermediate portion to which the upper tether is linked and the expansion direction intermediate portion to which the lower tether is linked.

[0010] According to the second aspect, the airbag main body has: an upper tether that links the deployment direction intermediate portion in the upper end portion of the apex chamber and the deployment direction intermediate portion in the upper end portion of the front-rear chamber; and a lower tether that links the deployment direction intermediate portion in the lower end portion of the apex chamber and the deployment direction intermediate portion in the lower end portion of the front-rear chamber. Moreover, the apex end portion of the apex chamber is folded back along an imaginary straight line that connects the deployment direction intermediate portion to which the upper tether is linked and the deployment direction intermediate portion to which the lower tether is linked. Thus, the apex end portion of the apex chamber is easily folded back.

[0011] Further, the seat-mounted type airbag device according to the third aspect is the seat-mounted type airbag device according to the second aspect in which the imaginary straight line extends in the seat vertical direction.

[0012] According to the third aspect, the imaginary straight line for folding back the apex end portion of the apex chamber extends in the seat vertical direction. That is, the upper tether and the lower tether are formed to be the same size. Thus, when the head of the occupant moves to the seat front side due to inertial force and is restrained by the airbag main body, the reaction force from the airbag main body is effectively ensured.

[0013] Further, the seat-mounted type airbag device according to the fourth aspect is the seat-mounted type airbag device according to the second aspect in which the imaginary straight line extends in the seat front-lower-rear-upper direction.

[0014] According to the fourth aspect, the imaginary straight line for folding back the apex end portion of the apex chamber extends in the seat front-lower-rear-upper direction. That is, in the apex chamber, the deployment direction intermediate portion to which the lower tether is linked is located at the front side compared to the deployment direction intermediate portion to which the upper tether is linked, and the lower tether is formed to be smaller compared to the upper tether. Thus, when the head of the occupant moves to the seat front side due to inertial force and is restrained by the airbag main body, the occupant's neck is suppressed from being caught on the lower tether.

[0015] Further, the seat-mounted type airbag device according to the fifth aspect is the seat-mounted type airbag device according to any one of the first to fourth aspects in which the airbag main body has a pleat portion that is continuously folded in a pleat shape from the outer roll portion toward the deployment direction upstream side.

[0016] According to a fifth aspect, the airbag main body has a pleated portion that is folded in a pleated shape continuously from the outer roll portion toward the upstream side in the deployment direction. Thus, the airbag main body first unfolds and deploys the pleated portion, and then unfolds and deploys the outer roll portion. Here, it is known that the pleated shape unfolds more quickly than the roll shape in general. Thus, the airbag main body can be deployed more quickly than in the case of having only the outer roll portion.

[0017] As described above, according to the present disclosure, it is possible to cause the airbag main body to deploy as planned in a seat-mounted type airbag device. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 A side view showing a state after deployment of the seat-mounted type airbag device according to the first embodiment.

[0019] Figure 2 A plan view showing a state after deployment of the seat-mounted type airbag device according to the first embodiment.

[0020] Figure 3 An enlarged plan view showing a state before deployment of the seat-mounted type airbag device according to the first embodiment in a manner that a portion thereof is broken.

[0021] Figure 4 An expanded view showing a folding manner of a top end chamber of the airbag main body in the seat-mounted type airbag device according to the first embodiment.

[0022] Figures 5A to 5D A plan view showing a deployment process of the seat-mounted type airbag device according to the first embodiment.

[0023] Figure 6A A side view corresponding to the plan view showing the deployment process of the seat-mounted type airbag device according to the first embodiment. Figure 5B

[0024] Figure 6B A side view corresponding to the plan view showing the deployment process of the seat-mounted type airbag device according to the first embodiment. Figure 5C

[0025] Figure 6C A side view corresponding to the plan view showing the deployment process of the seat-mounted type airbag device according to the first embodiment. Figure 5D

[0026] Figure 7 An expanded view showing a folding manner of a top end chamber of the airbag main body in the seat-mounted type airbag device according to the second embodiment.​​​

[0027] Figure 8A To illustrate the deployment process of the seat-mounted airbag device according to the second embodiment, and... Figure 5B A fairly accurate side view.

[0028] Figure 8B To illustrate the deployment process of the seat-mounted airbag device according to the second embodiment, and... Figure 5C A fairly accurate side view.

[0029] Figure 8C To illustrate the deployment process of the seat-mounted airbag device according to the second embodiment, and... Figure 5D A fairly accurate side view. Detailed Implementation

[0030] The embodiments disclosed herein will now be described in detail based on the accompanying drawings. For ease of explanation, the arrow UP, appropriately indicated in the drawings, will represent the direction upwards from the seat, the arrow FR the direction forwards from the seat, and the arrow RH the direction to the right from the seat. Therefore, in the following description, unless otherwise specified, the directions of up / down, front / back, and left / right will be used to represent the up / down, front / back, and left / right directions of a vehicle seat. Furthermore, the left / right direction is synonymous with the seat width direction.

[0031] like Figures 1 to 3 As shown, the seat-mounted airbag device (hereinafter simply referred to as "airbag device") 30 of this embodiment is disposed inside the housing portion 20, which constitutes the headrest 16 of the vehicle seat 10, which serves as the rear seat of the vehicle. Therefore, although the vehicle seat 10 of this embodiment is described as a rear seat, the airbag device 30 may also be disposed in the front seat.

[0032] Furthermore, as an example, the rear seat is configured with a left-side side window 18 (see reference). Figure 3 The rear seat on the side. Furthermore, as an example, "occupant P" in this embodiment refers to an occupant equivalent to the AM50 (50th percentile of adult males in the United States) of the WorldSID (World Side Impact Dummy).

[0033] <First Implementation Method>

[0034] First, the airbag device 30 according to the first embodiment will be described. Figure 1 , Figure 2As shown, the vehicle seat 10 has a seat cushion 12 on which an occupant P sits (supports the occupant P's hips and thighs), a seat back 14 that supports the occupant P's back, and a headrest 16 that supports the occupant P's head Ph.

[0035] As shown, the headrest 16 has a block-shaped main body portion 16A that is provided in the seat width direction center of the upper end portion of the seat back 14 in a liftable manner. If described in detail, a pair of left and right cylindrical headrest supports (not shown) are provided in the seat width direction center of the lower surface of the main body portion 16A. Figure 3

[0036] Each headrest support is inserted into a substantially cylindrical headrest support pillar 26 that is provided in the seat width direction center of the upper end portion of the seat back 14 in a pair of left and right, in a liftable and fixable manner at a plurality of predetermined positions. Thereby, the height position of the headrest 16 can be adjusted in accordance with the position of the occupant P's head Ph. Also, the headrest 16 has a housing portion 20 that is continuously provided from the rear of the main body portion 16A to both left and right sides.

[0037] The housing portion 20 is formed in a substantially "U" shape with the front side open when viewed from above. Also, the main body portion 16A of the headrest 16 is disposed with almost no gap at the inner side of the housing portion 20 thereof. Also, in the housing portion 20, the front end surface of the left and right side portions 24 (the outer surface of the front wall 20F) and the front surface of the main body portion 16A are substantially the same plane in the front-rear direction.

[0038] Further, the left and right outer side walls 20A (of the side portions 24) and the rear wall 20B in the housing portion 20 are composed of a resin-made cover member 22 that is formed in a substantially "U" shape when viewed from above. Also, the upper wall 20U (see Figure 1 、 Figure 2 ), lower wall (not shown), front wall 20F, and inner peripheral wall 20C of the housing portion 20 that opposes the main body portion 16A are composed in a manner that includes polyurethane foam (not shown) that is provided in a predetermined thickness, and the outer surfaces of the cover member 22 and the polyurethane foam are integrally covered with a skin material 21.

[0039] A predetermined space portion S (including the storage portion S1 and the arrangement portion S2 described later) is formed inside the housing portion 20. Also, in the storage portion S1 formed in the side portion 24R (the right side as the center seat side is shown) of the housing portion 20 on the opposite side from the side window glass 18, a safety airbag main body 32 of a safety airbag device 30 is stored.

[0040] As shown, the headrest 16 has a block-shaped main body portion 16A that is provided in the seat width direction center of the upper end portion of the seat back 14 in a liftable manner. If described in detail, a pair of left and right cylindrical headrest supports (not shown) are provided in the seat width direction center of the lower surface of the main body portion 16A. Figure 1 、 Figure 2 ​As shown, the airbag device 30 has an airbag body 32, which is inflated by an inflation device 28 described later (see reference). Figure 3 Gas is ejected, causing the airbag body 32 to deploy forward from the rear side (specifically the right rear side) of the head Ph of the occupant P who is seated on the vehicle seat 10.

[0041] The airbag body 32 has a front and rear chamber 34 and a top chamber 36. The front and rear chambers 34 extend forward from the right side of the occupant P's head Ph and are positioned to the right of the occupant P's head Ph (between the head Ph of the occupant P on the side window glass 18 side and the head of the occupant on the center seat side, not shown). The top chamber 36 extends inward from the front end of the front and rear chambers 34 in the seat width direction and is positioned in front of the occupant P's face and to the left of the occupant P's head Ph. In other words, the airbag body 32 is bent into a roughly "J" shape when viewed from below, thereby restraining at least the head Ph of the occupant P.

[0042] Furthermore, the airbag body 32 has a thinner, fabric-like upper tether 37 and a thinner, fabric-like lower tether 38 (see reference). Figure 1 The upper tether 37 connects the middle portion 36U in the unfolding direction at the upper end of the top chamber 36 and the middle portion 34U in the unfolding direction at the upper end of the front and rear chambers 34, and the lower tether 38 connects the middle portion 36D in the unfolding direction at the lower end of the top chamber 36 (refer to...). Figure 1 The middle part 34D in the unfolding direction of the lower end of the front and rear chambers 34 (refer to) Figure 1 ) to make a link.

[0043] To be more specific, when the airbag body 32 expands and deploys, the upper tether 37 is formed such that, when viewed from above, the straight rear end edge 37A connecting the middle part 36U in the deployment direction at the upper end of the top chamber 36 and the middle part 34U in the deployment direction at the upper end of the front and rear chambers 34 becomes a roughly right-angled triangle with a hypotenuse.

[0044] Furthermore, the peripheral portion of the upper tether 37, excluding its rear edge portion 37A, is sewn together from the middle portion 34U in the unfolding direction at the upper end of the front and rear chambers 34 to the middle portion 36U in the unfolding direction at the upper end of the top chamber 36, and is installed at the upper end of the front and rear chambers 34 and the top chamber 36.

[0045] Likewise, the lower tether 38 is formed so that, when the airbag main body 32 is inflated and deployed, a straight line-shaped rear end edge portion (omitted from the drawing) that connects the deployment direction middle portion 36D in the lower end portion of the roof chamber 36 and the deployment direction middle portion 34D in the lower end portion of the front and rear chamber 34 in a plan view becomes a substantially right-angled triangle shape with an oblique side.

[0046] Furthermore, the peripheral portion of the lower tether 38, except for the rear end edge portion thereof, is attached at the lower end portion of the front and rear chamber 34 and the lower end portion of the roof chamber 36 by sewing from the deployment direction middle portion 34D in the lower end portion of the front and rear chamber 34 to the deployment direction middle portion 36D in the lower end portion of the roof chamber 36.

[0047] In addition, since the upper tether 37 is positioned at the upper side of the head Ph of the occupant P, it does not interfere with (does not hit) the head Ph of the occupant P. Furthermore, although the lower tether 38 is positioned at the neck of the occupant P, since it is a thin cloth as described above, even if it interferes with (even if it hits) the neck, the damage value given to the neck is low.

[0048] As shown in FIG. 2, the airbag main body 32 is formed in a substantially rectangular shape in a plan view. The airbag main body 32 is formed so that the roof chamber 36 is positioned at the upper side of the front and rear chamber 34. Figure 3 As shown in FIG. 2, the airbag main body 32 is formed in a substantially rectangular shape in a plan view. The airbag main body 32 is formed so that the roof chamber 36 is positioned at the upper side of the front and rear chamber 34.

[0049] The reaction force plate is fixed to the seat back frame (omitted from the drawing) via a bracket (omitted from the drawing), for example, and becomes a structure that receives the reaction force transmitted from the airbag main body 32 that is deployed to the front side via the inflator 28. In addition, the reaction force plate and the holder are also disposed in the disposition portion S2.

[0050] The inflator 28 is electrically connected to the airbag ECU (omitted from the drawing) provided on the vehicle, and the detection device (omitted from the drawing) such as an acceleration sensor provided on the vehicle and the airbag ECU are electrically connected together. Therefore, when the collision of the vehicle is detected by the detection device, the inflator 28 is operated via the airbag ECU, and gas is instantaneously ejected.

[0051] In addition, the inflator 28 can not be a structure that is operated by detecting the collision of the vehicle, but can be a structure that is operated by predicting the collision of the vehicle by using a collision prediction sensor or the like (omitted from the drawing). Furthermore, in the ejection port of the inflator 28, the connection portion 31 of the airbag main body 32 is connected in a manner of being embedded.

[0052] Further, as shown in Figure 4 , the airbag main body 32 is folded back at the top end portion 36A of the top end chamber 36 on the opposite side to the occupant P side (the side not in contact with the head Ph) and, as shown in Figure 3 , is outer-rolled into a roll shape with the up-down direction as the axis (in plan view, in a state with an outer-rolled portion 32A having a roll shape at the seat width direction outer side) and is housed in the housing portion SI formed in the side portion 24R.

[0053] If explained in more detail, the top end portion 36A of the top end chamber 36 is folded back along an imaginary straight line Kl that connects the up-direction intermediate portion 36U to which the upper tether 37 is linked and the down-direction intermediate portion 36D to which the lower tether 38 is linked (a straight line extending in the up-down direction), as shown in Figure 4 . Also, in this state, from the boundary portion 35 side of the front-rear chamber 34 and the top end chamber 36, it is sequentially outer-rolled into a roll shape with the up-down direction as the axis.

[0054] Further, as shown in Figure 3 , at the up-stream side in the deployment direction of the outer-rolled portion 32A, a crumpled portion 32B is formed continuously with the outer-rolled portion 32A. That is, the airbag main body 32 is housed in the housing portion SI in a state with the crumpled portion 32B folded into a crumpled shape continuously from the outer-rolled portion 32A to the up-stream side in the deployment direction.

[0055] Therefore, as shown in Figure 5A , Figure 5B , when the airbag main body 32 deploys from the right side of the head Ph of the occupant P from the side portion 24R to the front side by the gas ejected from the inflator 28, it first unwinds and deploys the crumpled portion 32B and then unwinds and deploys the outer-rolled portion 32A.

[0056] In addition, although Figure 3 the crumpled portion 32B is formed with two groups in the case of the portion folded into two being one group, it is not limited thereto. The crumpled portion 32B can be formed with multiple groups, and it can be formed with three or more groups.

[0057] Further, the front wall 2OF constituting the front end face of the side portion 24R is broken along with the deployment of the airbag main body 32, for example, in a straight line shape in the up-down direction in front view, together with a portion of the upper wall 2OU on the front wall 2OF side. The broken portion is preferably set to the seat width direction inner end portion 2ON of the front wall 2OF.

[0058] When the broken portion is the seat width direction inner end portion 20N of the front wall 20F (for example, when a fragile portion or the like that is easily broken is formed at the seat width direction inner end portion 20N of the front wall 20F), the front wall 20F is opened with the seat width direction outer end portion 20T as the hinge portion.

[0059] Next, the operation of the airbag device 30 according to the first embodiment configured as described above will be described.

[0060] When the detection device detects that the vehicle has undergone a front collision, the inflator 28 operates, and gas is instantaneously injected into the inside of the airbag main body 32. When the gas is injected into the inside of the airbag main body 32, the front wall 20F of the side portion 24R is broken together with a portion of the front wall 20F of the upper wall 20U by the deployment of the airbag main body 32 (by being pressed from the inside by the airbag main body 32).

[0061] Further, the airbag main body 32 deploys from the right side of the head Ph of the occupant P (a gap between the head Ph of the occupant P on the side window glass 18 side and the head of the occupant on the center seat side, which is not shown) and to the front side from the side portion 24R. That is, the airbag main body 32 first unwinds and deploys the pleat portion 32B folded in a pleat shape (see Figure 5A ), and then unwinds and deploys the outer roll portion 32A rolled in a roll shape.

[0062] Here, it is known that in general, the pleat shape side unwinds more quickly than the roll shape (the resistance when the pleat shape side deploys is smaller than that when the roll shape deploys). Therefore, compared to the airbag main body 32 having only the outer roll portion 32A, the airbag main body 32 having the outer roll portion 32A and the pleat portion 32B in this order from the downstream side in the direction of deployment deploys more quickly to the front side.

[0063] Further, as shown in Figure 5B , Figure 6A when the front-rear chamber 34 is inflated and deployed and disposed at the right side of the head Ph of the occupant P, the gas flows from the front side end portion of the front-rear chamber 34 to the apex chamber 36, and the apex chamber 36 is inflated and deployed to the seat width direction inner side, but at this time, the apex portion 36A of the apex chamber 36 is folded back to the opposite side to the occupant P side.

[0064] Therefore, the apex portion 36A of the apex chamber 36 deploys last. That is, the apex portion 36A of the apex chamber 36 deploys after the front side of the face of the occupant P. By this, it is possible to prevent the apex chamber 36 from interfering with (hitting) the head Ph of the occupant P before the front side of the face of the occupant P, and it is possible to deploy the airbag main body 32 in a manner that does not interfere with the occupant P. Figure 5C ,Figure 6B as well as Figure 5D , Figure 6C As shown, the airbag body 32 deploys as planned.

[0065] Furthermore, the fully deployed airbag body 32 (front and rear chambers 34 and top chamber 36) restrains at least the head Ph of the occupant P seated on the vehicle seat 10. That is, the airbag body 32 (front and rear chambers 34 and top chamber 36) can prevent at least the head Ph of the occupant P from moving forward due to inertial forces.

[0066] Furthermore, as mentioned above, since the outwardly rolled portion 32A of the airbag body 32 unrolls and unfolds forward, there is no possibility of the occupant P's face being injured by the airbag body 32 when it unfolds. Moreover, when the airbag body 32 is configured such that the outer end 20T of the front wall 20F in the seat width direction is opened as a hinge when it unfolds, the airbag body 32 can prevent the unfolded front wall 20F from contacting the occupant P's head Ph.

[0067] Furthermore, the top end 36A of the top chamber 36 is folded back along an imaginary straight line K1 connecting the middle part 36U in the unfolding direction connected to the upper tether 37 and the middle part 36D in the unfolding direction connected to the lower tether 38. Therefore, it is easy to fold back the top end 36A of the top chamber 36.

[0068] Furthermore, when the imaginary straight line K1 used to fold back the top part 36A of the top chamber 36 extends in the vertical direction, and the upper tether 37 and the lower tether 38 are formed to be the same size, the reaction force from the airbag body 32 can be effectively ensured when the head Ph of the occupant P moves forward due to inertial force and is restrained by the airbag body 32.

[0069] <Second Implementation Method>

[0070] Next, the airbag device 30 according to the second embodiment will be described. Furthermore, the same symbols will be used for parts equivalent to those in the first embodiment described above, and detailed descriptions (including common functions) will be appropriately omitted.

[0071] like Figures 7 to 8C As shown, the airbag body 32 of the airbag device 30 in the second embodiment differs from the shape of the lower tether 39 in the first embodiment. Therefore, only the folded-back portion of the top end 36A of the top chamber 36 differs from the first embodiment.

[0072] That is, the lower tether 39 is formed so that, when the airbag main body 32 is inflated and deployed, a straight line-shaped rear end edge portion (omitted from the drawing) connecting the deployment direction intermediate portion 36E in the lower end portion of the roof chamber 36, which is located on the boundary portion 35 side as compared with the deployment direction intermediate portion 36D of the first embodiment, and the deployment direction intermediate portion 34D in the lower end portion of the front-rear chamber 34, which is an oblique side of a substantially right-angled triangle shape when viewed from the bottom.

[0073] Further, the peripheral portion of the lower tether 39, except for the rear end edge portion thereof, is attached at the lower end portion of the front-rear chamber 34 and the lower end portion of the roof chamber 36 by sewing from the deployment direction intermediate portion 34D in the lower end portion of the front-rear chamber 34 to the deployment direction intermediate portion 36E in the lower end portion of the roof chamber 36, which is located on the boundary portion 35 side as compared with the deployment direction intermediate portion 36D of the first embodiment.

[0074] Furthermore, the top end portion 36A of the roof chamber 36 in the airbag main body 32 is folded back to the opposite side (the side not in contact with the head Ph) of the occupant P side along an imaginary straight line K2 connecting the deployment direction intermediate portion 36U to which the upper tether 37 is linked and the deployment direction intermediate portion 36E to which the lower tether 39 is linked.

[0075] That is, the imaginary straight line K2 for folding back the top end portion 36A of the roof chamber 36 extends in the front lower-rear upper direction, and in the roof chamber 36, the deployment direction intermediate portion 36E to which the lower tether 39 is linked is located on the front side as compared with the deployment direction intermediate portion 36U to which the upper tether 37 is linked.

[0076] In other words, the lower tether 39 is formed to be smaller than the upper tether 37 so that the straight line-shaped rear end edge portion connecting the deployment direction intermediate portion 36E in the lower end portion of the roof chamber 36 and the deployment direction intermediate portion 34D in the lower end portion of the front-rear chamber 34 is located on the front side as compared with the case of the first embodiment. Therefore, when the head Ph of the occupant P moves to the front side due to inertial force and is restrained by the airbag main body 32, it is possible to suppress or prevent the neck of the occupant P from being caught on the lower tether 39.

[0077] That is, in the case of the airbag device 30 related to the second embodiment, even if the airbag main body 32 is inflated and deployed, the lower tether 39 does not interfere with (does not hit) the neck of the occupant P, or even if it does interfere (even if it does hit), it is extremely slight. Therefore, according to the lower tether 39 in the second embodiment, it is possible to further reduce the injury value to the neck of the occupant P as compared with the lower tether 38 in the above-described first embodiment.

[0078] While the seat-mounted type airbag device 30 according to the present embodiment has been described above based on the drawings, the seat-mounted type airbag device 30 according to the present embodiment is not limited to the illustrated content, and can be appropriately designed to change within a range not departing from the gist of the present disclosure. For example, the reaction plate that supports the inflator 28 can not be fixed to the seat back frame, but can be fixed to the headrest pillar 26 via a bracket.

[0079] Further, while the structure in which the airbag main body 32 is inflated and deployed between the head Ph of the occupant P from the side window glass 18 side and the head of the occupant on the center seat side, which is not illustrated, has been described as an example in the present embodiment, the airbag main body 32 can also be provided in a structure that is inflated and deployed from between the side window glass 18 and the head Ph of the occupant P.

[0080] Symbol Explanation

[0081] 28…inflator;

[0082] 30…airbag device (seat-mounted type airbag device);

[0083] 32…airbag main body;

[0084] 32A…outer roll portion;

[0085] 32B…pleated portion;

[0086] 34…front and rear chambers;

[0087] 36…top end chamber;

[0088] 36A…top end portion;

[0089] 37…upper tether;

[0090] 38…lower tether;

[0091] 39…lower tether;

[0092] K1…imaginary straight line;

[0093] K2…imaginary straight line;

[0094] P…occupant;

[0095] Ph…head.

Claims

1. A seat-mounted airbag device, wherein, The airbag body comprises a front and rear chamber and a top chamber. The front and rear chambers are propelled by gas ejected from an inflation device that operates based on the detection or prediction of a vehicle collision, passing through the side of the occupant's head and expanding toward the front of the seat, and are positioned at the side of the occupant's head. The top chamber expands inward in the seat width direction from the front end of the front and rear chambers and is positioned at the front of the occupant's face. After the airbag body is folded back from the top of the top chamber towards the opposite side of the occupant, it is stored in a state where it is rolled outward into a cylindrical shape with the vertical direction of the seat as the axis. The airbag body also has: The upper rope connects the middle part of the upper end of the top chamber in the unfolding direction to the middle part of the upper end of the front and rear chambers in the unfolding direction. The lower part is tied with a rope that connects the middle part of the lower end of the top chamber in the unfolding direction to the middle part of the lower end of the front and rear chambers in the unfolding direction.

2. The seat-mounted airbag device as described in claim 1, wherein, The top of the top chamber is folded back along an imaginary straight line, which is a straight line connecting the middle part of the unfolding direction to which the upper tether is connected and the middle part of the unfolding direction to which the lower tether is connected.

3. The seat-mounted airbag device as described in claim 2, wherein, The imaginary straight line extends along the vertical direction of the seat.

4. The seat-mounted airbag device as described in claim 2, wherein, The imaginary straight line extends along the front-down and rear-up direction of the seat.

5. The seat-mounted airbag device according to any one of claims 1 to 4, wherein, The airbag body has a pleated portion, which is continuously folded into a pleated shape from the outer roll portion upstream in the unfolding direction.

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