Airbag device attached to seat

Abstract

The present disclosure provides an airbag device attached to a seat, the airbag device being provided with: front and rear chambers which are inflated and deployed forward through both the left and right sides of the head of an occupant by being supplied with gas ejected from an inflator at the time of a vehicle collision; and an airbag body that moves forward through a space between the head of the occupant and the ceiling of the vehicle cabin as the front and rear chambers are inflated and deployed, is inflated and deployed by being supplied with gas from the front and rear chambers, and is disposed forward of the occupant. The airbag is housed in the headrest by bending the front and rear chambers downward with respect to the airbag body, and a discharge port for the gas discharged from the inflator is located at a vertically central portion on the rear side of the front and rear chambers.

Description

Technical Field

[0001] The present disclosure relates to an airbag device attached to a seat. Background Art

[0002] An airbag device with an airbag has long been known, which includes: a rear inflation portion that deploys on the back side of a seat; a pair of side inflation portions that extend forward from the left and right sides of the rear inflation portion; and a pair of front inflation portions that extend from the side inflation portions toward the center side and are connected to each other at the center side to cover the front of the occupant (for example, refer to Japanese Patent Gazette No. 2019-218013 (Patent Document 1)).

[0003] In addition, there has long been known an airbag device having a bag body, the bag body having: a body support portion that is deployed from behind the occupant's head to the front of the occupant; a pair of head support portions that are deployed at the left and right sides of the occupant's head and connected to the body support portion (for example, see Japanese Patent Publication No. 2019-018593 (Patent Document 2)). The bag body is formed with an avoidance portion that passes through the pair of head support portions in the vertical direction and avoids the occupant's head in the deployed state. Summary of the invention

[0004] Problems to be solved by the invention

[0005] In the above-mentioned airbag device, the airbag (bag body) is inflated and deployed while passing through the gap between the head of the occupant and the ceiling from the seat back, so as to be arranged in front of the occupant. However, if there is a deviation in the folding method of the airbag, the inflated and deployed airbag will swing in the vertical direction and the left-right direction, so that its deployment action may be unstable.

[0006] Therefore, an object of the present disclosure is to obtain a seat-attached airbag device that stabilizes the deployment operation of an airbag main body that is arranged in front of the seat of the occupant by passing between the head of the occupant and the ceiling of the vehicle cabin to inflate and deploy.

[0007] Means for solving problems

[0008] In order to achieve the above-mentioned purpose, a first mode of an airbag device attached to a seat comprises: an inflator, which is arranged on a vehicle seat and ejects gas when the vehicle collides; an airbag, which has a pair of front and rear chambers and an airbag body, wherein the pair of front and rear chambers are supplied with gas ejected from the inflator, so that they inflate and deploy toward the front side of the seat through the left and right sides of the head of an occupant sitting on the vehicle seat, and the airbag body moves toward the front side of the seat through the space between the head of the occupant and the ceiling of the vehicle compartment as the pair of front and rear chambers inflate and deploy. The airbag is configured at the front side of the seat of the occupant by being moved and by being supplied with the gas from the pair of front and rear chambers, thereby expanding and deploying toward the rear side of the seat between the pair of front and rear chambers. When the airbag is viewed from the front side of the seat, the pair of front and rear chambers are bent toward the lower side of the seat relative to the airbag body and are accommodated in the headrest of the vehicle seat. When viewed from the side in the seat width direction, the outlet of the gas ejected from the inflation device is located at the center in the up-down direction of the pair of front and rear chambers at the rear side of the seat.

[0009] According to the first method, when a vehicle collides, the gas ejected from the inflator is supplied to a pair of front and rear chambers, and the pair of front and rear chambers expand and deploy toward the front side of the seat through the left and right sides of the head of the occupant sitting on the vehicle seat. Moreover, as the pair of front and rear chambers expand and deploy, the airbag body passes between the head of the occupant sitting on the vehicle seat and the ceiling of the vehicle compartment and moves toward the front side of the seat, and is supplied with gas from the pair of front and rear chambers, thereby expanding and deploying toward the rear side of the seat between the pair of front and rear chambers, and is arranged at the front side of the seat of the occupant. In addition, the "collision" mentioned here also includes the inevitable situation of predicting (foreseeing) a collision.

[0010] Here, when the airbag is observed in a front view from the front side of the seat, a pair of front and rear chambers are bent toward the lower side of the seat relative to the airbag body and are accommodated in the headrest of the vehicle seat, and when observed in a side view from the seat width direction, the gas outlet ejected from the inflation device is located in the center portion in the vertical direction of the pair of front and rear chambers on the rear side of the seat.

[0011] Therefore, when the expansion and deployment of the pair of front and rear chambers begins, the vertical center of the pair of front and rear chambers on the rear side of the seat can be pushed toward the front side of the seat, thereby stabilizing the deployment direction of the pair of front and rear chambers. In other words, the deployment action of the airbag body arranged on the front side of the seat of the occupant is stabilized by passing between the head of the occupant and the ceiling of the vehicle and expanding and deploying. In addition, the "vertical center" mentioned here includes the vertical approximate center that is slightly deviated from the center in the vertical direction.

[0012] In addition, the second type of airbag device attached to a seat is, in the first type of airbag device attached to a seat, provided with a distribution pipe, the distribution pipe is arranged on the vehicle seat, and can supply the gas ejected from the inflation device to the pair of front and rear chambers respectively, the distribution pipe has a nozzle connected to the root of the pair of front and rear chambers respectively, the nozzle extends to the upper front side of the seat by a predetermined length when viewed from the side in the seat width direction, and is located in the center part in the up and down direction of the pair of front and rear chambers at the rear side of the seat.

[0013] According to the second embodiment, a distribution pipe capable of supplying gas ejected from an inflator to a pair of front and rear chambers is provided on the vehicle seat, and the distribution pipe has a discharge port connected to the root of the pair of front and rear chambers, respectively. Moreover, the discharge port extends to the upper front side of the seat by a predetermined length when viewed from the side in the seat width direction, and is located at the center of the pair of front and rear chambers in the vertical direction at the rear side of the seat.

[0014] Therefore, when the expansion and deployment of a pair of front and rear chambers begins, the central portion in the vertical direction of the pair of front and rear chambers at the rear side of the seat can be pushed toward the front side of the seat more effectively, thereby stabilizing the deployment direction of the pair of front and rear chambers. In addition, since the distribution pipe is provided, the mounting position of the inflator is not restricted. Therefore, for example, the inflator can be mounted along the extension direction of the seat back, thereby suppressing the enlargement of the seat back (increase in thickness). In addition, the "central portion in the vertical direction" mentioned here also includes the approximate central portion in the vertical direction that is slightly deviated from the central portion in the vertical direction.

[0015] In addition, a third type of seat-attached airbag device is that, in the seat-attached airbag device of the first or second type, the root of the pair of front and rear chambers connected to the ejection port is accommodated in the headrest in a state bent into an upward convex shape when viewed from the side in the seat width direction.

[0016] According to the third aspect, the root of the pair of front and rear chambers connected to the ejection port is stored in a state of being bent into an upward convex shape when viewed from the side in the seat width direction. Therefore, when the root of the pair of front and rear chambers expands, the center of the front and rear chambers in the vertical direction at the rear side of the seat can be pushed toward the lower side of the front of the seat, thereby more effectively stabilizing the deployment direction of the pair of front and rear chambers.

[0017] Effects of the Invention

[0018] As described above, according to the present disclosure, the deployment operation of the airbag main body that is inflated and deployed by passing between the head of the occupant and the ceiling of the vehicle compartment and is arranged in front of the seat of the occupant can be stabilized. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic perspective view showing a state in which the airbag of the seat-attached airbag device according to the first embodiment is inflated and deployed.

[0020] Figure 2 It is a schematic side view showing a state in which the airbag of the seat-attached airbag device according to the first embodiment is inflated and deployed.

[0021] Figure 3 It is a schematic plan view showing a state in which the airbag of the seat-attached airbag device according to the first embodiment is inflated and deployed.

[0022] Figure 4 It is a schematic plan view showing the shape of the airbag before folding according to the first embodiment.

[0023] Figure 5A for Figure 4 An enlarged cross-sectional view of the XX line.

[0024] Figure 5B for Figure 4 The enlarged cross-sectional view shown along the YY line.

[0025] 6A to 6F It is a schematic plan view showing a folding step of the airbag in the first embodiment.

[0026] Figure 7 It is a schematic plan view showing the folded shape of the airbag according to the first embodiment.

[0027] Figure 8 It is a schematic front view showing, in partial section, the airbag accommodated in the headrest in the first embodiment.

[0028] Fig. 9 It is a schematic front view showing the shape of the distribution pipe in the first embodiment with a partial cross section and with the airbag omitted.

[0029] Fig.10 It is a schematic side view showing, in partial cross section, the airbag accommodated in the headrest according to the first embodiment.

[0030] Fig.11 It is a schematic plan view showing, in partial cross section, the airbag accommodated in the headrest according to the first embodiment.

[0031] Fig.12 This is a schematic side view showing the initial stage of inflation and deployment of the airbag according to the first embodiment.

[0032] Fig.13This is a schematic side view showing the airbag in the middle stage of inflation and deployment according to the first embodiment.

[0033] Fig.14 This is a schematic side view showing the airbag in the late stage of inflation and deployment according to the first embodiment.

[0034] Fig.15A This is a schematic side view showing a state before gas is supplied to the airbag in the second embodiment in partial cross section.

[0035] Fig. 15B This is a schematic side view showing a state immediately after gas is supplied to the airbag in the second embodiment in a partial cross-section. DETAILED DESCRIPTION

[0036] Hereinafter, the embodiments of the present invention will be described in detail based on the accompanying drawings. In addition, for the convenience of description, the arrow mark UP appropriately shown in each figure is set to the top of the vehicle and the vehicle seat, the arrow mark FR is set to the front of the vehicle and the vehicle seat, the arrow mark RH is set to the right of the vehicle and the vehicle seat, and the arrow mark LH is set to the left of the vehicle and the vehicle seat. Therefore, in the following description, when the up-down, front-back, left-right directions are recorded without special description, they are set to represent the up-down, front-back, left-right of the vehicle and the vehicle seat. In addition, the left-right direction is synonymous with the vehicle width direction and the seat width direction.

[0037] <First Embodiment>

[0038] First, an airbag device (hereinafter referred to as "airbag device") 30 attached to a seat according to a first embodiment will be described. Figure 1 As shown, the occupant protection device 10 is composed of a vehicle seat 12 and an airbag device 30. The vehicle seat 12 is a front seat or a rear seat of a vehicle (car). Figure 12 to Figure 14 ) is set as the vehicle seat 12, but the rear seat is set as the vehicle seat 12.

[0039] In addition, Figures 1 to 3 In the figure, as a model of the occupant (seat occupant) to be protected, a collision test dummy (human dummy) is shown seated on the vehicle seat 12. The dummy is, for example, an AM50 (50th percentile of American adult males) dummy (Hybrid III) for a frontal collision test. The dummy sits in a standard sitting posture prescribed by the collision test method, and the vehicle seat 12 is located at a reference setting position corresponding to the sitting posture. Hereinafter, the dummy is referred to as "occupant D".

[0040] The vehicle seat 12 includes: a seat cushion 14 on which an occupant D sits (supporting the buttocks and thighs F of the occupant D); and a seat back 16 which is arranged to extend upward from the rear side of the seat cushion 14 when viewed from the side in the seat width direction and is rotatable with the seat width direction as an axial direction, and supports the back of the occupant D. Moreover, the seat back 16 has an integral headrest 18 at the center of the upper end portion in the seat width direction for supporting the head H of the occupant D. In addition, the rear wall of the headrest 18 is formed by a back plate 19 (see Fig.10 )constitute.

[0041] like Figures 1 to 3 As shown, an occupant D sitting on a seat cushion 14 of a vehicle seat 12 is restrained on the vehicle seat 12 by a seat belt 22 provided in a seat belt device 20. The seat belt device 20 is a three-point seat belt device, and is a so-called seat belt device attached to the seat, in which a retractor, an anchor, and a buckle (not shown) are all provided on the vehicle seat 12.

[0042] The airbag device 30 includes an airbag 32 and a single inflator 44 (see Fig. 9 , Fig.10 The airbag 32 is normally stored in a folded state inside the headrest 18 (see Figure 8 , Fig.10 , Fig.11 The inflator 44 is a cylinder type formed into a substantially cylindrical shape, for example, by a combustion type or a low temperature gas type, and is provided inside the seat back 16 or from the inside of the seat back 16 to the inside of the headrest 18 along the extension direction of the seat back 16 (with the axial direction oriented in the up-down direction).

[0043] In addition, the airbag device 30 includes a control device (ECU) (not shown) that controls the operation of the inflator 44. The control device is electrically connected to the inflator 44 and a collision sensor (including a camera, etc.) (not shown), and is configured to detect a frontal collision of the vehicle or predict the inevitability of a frontal collision. Furthermore, when the control device detects or predicts a frontal collision of the vehicle based on information from the collision sensor, the inflator 44 is operated.

[0044] That is, the inflator 44 is configured to generate gas and discharge the gas from the ejection port 44A (see FIG. 4A ) by being operated by the control device when a frontal collision of the vehicle is detected or predicted (hereinafter sometimes referred to as “frontal collision of the vehicle”). Fig. 9 , Fig.10) is ejected. In addition, the frontal collision of the vehicle in which the control device operates the inflator 44 includes, in addition to a full overlap frontal collision, an eccentric frontal collision such as an oblique collision and a slight overlap collision.

[0045] The airbag 32 is supplied with gas ejected from the inflator 44, and is deployed and inflated forward from the front surface of the headrest 18 through the left and right sides of the head H of the occupant D sitting on the vehicle seat 12 and the upper side of the head H of the occupant D. Specifically, the airbag 32 includes a pair of front and rear chambers 34 and an airbag body 40.

[0046] like Figure 4 As shown, the pair of front and rear chambers 34 have: a pair of left and right front and rear extension portions 34A, which are supplied with gas ejected from the inflator 44, and expand and expand forwardly through the left and right sides of the head H of the occupant D and extend in the front-rear direction; a front side connecting portion 34B (refer to Figures 1 to 3 ), which connects the front end portions of a pair of front and rear extension portions 34A in the left-right direction; and a rear connecting portion 34C, which connects the rear end portions of a pair of front and rear extension portions 34A in the left-right direction.

[0047] The front connecting portion 34B is formed in a substantially T-shaped bag shape (see FIG. 1 ) continuous with the pair of front and rear extending portions 34A. Figures 1 to 3 ). In addition, at the rear ends of the pair of front and rear chambers 34 (front and rear extensions 34A), in other words, at both ends in the seat width direction at the rear surface of the rear side connecting portion 34C, cylindrical roots 36 extending to the rear side are formed integrally, and at the center portion in the seat width direction at the rear surface of the rear side connecting portion 34C, a cylindrical root 38 extending to the rear side is also formed integrally.

[0048] In the following description, the root 36 on the left side is sometimes referred to as "root 36L" and the root 36 on the right side is sometimes referred to as "root 36R". In addition, the left and right roots 36 and the central root 38 are respectively connected to the outlets 46A and 48A of the branch pipes 46 and 48 of the distribution pipe (diffuser) 50 described later. In addition, the front and rear chambers 34 are formed by overlapping two long base fabrics and sewing the upper and lower peripheral portions thereof together (see Figure 5B ), thereby forming a long bag shape (tube shape).

[0049] The airbag body 40 is deployed along with the expansion of the pair of front and rear chambers 34 (front and rear extensions 34A) and penetrates the head H of the occupant D and the ceiling 28 of the vehicle compartment (see FIG. Figure 12 to Figure 14) between the pair of front and rear chambers 34 and move forward, gas is supplied from a pair of front and rear chambers 34, thereby expanding and deploying toward the occupant D side (rear side) at the rear side of the front connecting portion 34B in a delayed manner relative to the pair of front and rear chambers 34, and is arranged between the pair of front and rear chambers 34 (front and rear extension portions 34A) and in front of the occupant D.

[0050] The airbag body 40 is formed by folding a base fabric into a predetermined shape and sewing its peripheral edges together (see Figure 5A ), thereby forming a bag shape. Furthermore, the periphery of the communicating hole (not shown) formed on the rear surface of the left-right central portion of the base fabric of the front side connecting portion 34B constituting the front and rear chambers 34 and the periphery of the communicating hole (not shown) formed on the base fabric of the airbag body 40 are sewn together, thereby connecting the two. In addition, the base fabric of the front and rear chambers 34 and the base fabric of the airbag body 40 are respectively made of, for example, polyamide or polyester fabrics.

[0051] In addition, if Figure 4 , Figure 5A As shown, before the airbag body 40 is folded (wound) into a roll shape, the base fabrics 40A placed on the left and right sides of the inner side in the seat width direction are pulled outward in the seat width direction and flattened to be roughly flat. Figure 4 , Figure 5B As shown, before the pair of front and rear chambers 34 are folded into a corrugated shape (corrugated shape), the substantially vertical center portion of the base fabric 34D is stretched outward in the seat width direction and flattened to be substantially flat.

[0052] In this state, the airbag 32 is folded as shown in FIG6. That is, first, FIG. 6A to FIG. 6C As shown, the airbag body 40 is rolled up from the front side into a roll shape. In other words, the airbag body 40 is folded into an outwardly rolled roll shape so as to be easily unrolled by the inertial force accompanying the movement toward the front side.

[0053] Next, if FIG. 6D to FIG. 6F As shown, the pair of front and rear chambers 34 (front and rear extensions 34A) are folded into a corrugated shape. In addition, the folded shape of the pair of front and rear chambers 34 (front and rear extensions 34A) is a corrugated fold that only forms three peaks. Fig. 6F 4 shows a state where the branch pipes 46 and 48 of a distribution pipe 50 described later are connected.

[0054] So, in Figure 74 shows a folded state, where the boundary 42 between the airbag body 40 folded into a roll and the pair of front and rear chambers 34 folded into an accordion shape is a folded portion, and the pair of front and rear chambers 34 are bent downward. Figure 8 As described above, it is accommodated inside the headrest 18 .

[0055] That is, the airbag 32 is configured to be arranged along the outer shape (upper surface and left and right side surfaces) of the headrest 18 when viewed from the front. Figure 8 In the airbag 32 shown in the state before the pair of front and rear chambers 34 are bent downward, the length from the center line of the airbag body 40 in the seat width direction (not shown) to the outer ends of the front and rear chambers 34 in the seat width direction is 200 mm to 400 mm, and the position of the boundary portion 42 is approximately 100 mm to 200 mm away from the outer ends of the front and rear chambers 34 in the seat width direction.

[0056] In addition, a tear line (not shown) is formed on the front surface of the headrest 18. The tear line is configured to be ruptured by the inflation pressure of the airbag 32 when the airbag 32 is inflated and deployed. Thus, the airbag 32 can be inflated and deployed from the front surface of the headrest 18 toward the front side in the order of the pair of front and rear chambers 34 and the airbag body 40.

[0057] In addition, if Fig. 9 As shown in FIG. 1 , a distribution pipe 50 made of resin or metal is arranged at the rear side of the inside of the headrest 18. The distribution pipe 50 branches in three directions and has a cylindrical branch pipe 46 that branches to the left and right from the center of the seat width direction, and a cylindrical branch pipe 48 that branches to the upper side from the center of the seat width direction. In addition, in the following description, the branch pipe 46 that branches to the left from the center of the seat width direction of the distribution pipe 50 is sometimes referred to as "branch pipe 46L", and the branch pipe 46 that branches to the right from the center of the seat width direction of the distribution pipe 50 is sometimes referred to as "branch pipe 46R".

[0058] like Fig.10 As shown, the nozzle 46A of the left branch pipe 46L and the nozzle 46A of the right branch pipe 46R extend toward the upper front side at a predetermined angle (for example, 20° to 30° relative to the horizontal direction) and a predetermined length when viewed from the side, and the nozzle 48A of the upper branch pipe 48 also extends toward the upper front side at a predetermined angle (for example, 20° to 30° relative to the horizontal direction) and a predetermined length when viewed from the side.

[0059] The "predetermined length" of the jet outlet 46A and the jet outlet 48A mentioned here is preferably set to 30 mm to 40 mm, for example. This is because if the length of the jet outlet 46A and the jet outlet 48A is shorter than 30 mm, the gas may not be ejected in the target direction, and if it is longer than 40 mm, the thickness of the headrest 18 will increase meaninglessly.

[0060] In addition, if Fig.11 As shown in FIG. 1 , the ejection outlet 46A of the left branch pipe 46L and the ejection outlet 46A of the right branch pipe 46R also extend forward and outward in the seat width direction at a predetermined angle (e.g., 10° to 20° with respect to the front-rear direction) in a plan view. As a result, the pair of front and rear chambers 34 expand and deploy forward and outward in the seat width direction, and the rolled airbag body 40 is stretched outward in the seat width direction and moves from the rear side to the front side.

[0061] And, if Figure 4 , Fig. 6F As shown, the outlet 46A of the left branch pipe 46L and the outlet 46A of the right branch pipe 46R are connected to the left root 36L and the right root 36R of the rear connecting portion 34C, respectively, and the outlet 48A of the upper branch pipe 48 is connected to the central root 38 of the rear connecting portion 34C. Fig.10 As shown, in the state where the airbag 32 is stored inside the headrest 18, the left and right root portions 36L and 36R (in Fig.10 Only the root 36L on the left side is shown in the figure) and is located approximately in the center in the up-down direction at the rear side of a pair of front and rear chambers 34.

[0062] In other words, when viewed from the side, the outlet 46A of the left branch pipe 46L and the outlet 46R of the right branch pipe 46L (at Fig.10 The outlet 46A of the branch pipe 46L (only the left side is shown) is located at the approximately middle part in the vertical direction of the rear side of the pair of front and rear chambers 34. Fig. 9 As shown, the inner diameters of the discharge port 46A of the left branch pipe 46L and the discharge port 46A of the right branch pipe 46R are set to be the same, and are formed to be larger than the inner diameter of the discharge port 48A of the upper branch pipe 48 (for example, about 1.2 times larger).

[0063] Furthermore, the discharge port 44A of the inflator 44 is connected to the cylindrical base 52 extending downward from the center portion in the seat width direction of the distribution pipe 50. That is, the inflator 44 is configured to discharge gas into the inside of the left branch pipe 46L and the right branch pipe 46R of the distribution pipe 50 which can supply gas to the pair of front and rear chambers 34, respectively, and is configured to discharge gas into the inside of the upper branch pipe 48 of the distribution pipe 50 which can supply gas to the center of the rear connecting portion 34C.

[0064] In the airbag device 30 having the above structure, Figures 1 to 3 As shown in the figure, the front and rear extensions 34A of the pair of front and rear chambers 34 after expansion and deployment extend in the front and rear direction at the left and right sides of the head H of the occupant D, and are opposed to the head H with gaps on both sides. In addition, the front end portions of the pair of front and rear extensions 34A after expansion and deployment are connected in the left and right directions by the front connecting portion 34B after expansion and deployment. As a result, the front and rear chambers 34 including the pair of front and rear extensions 34A protruding from the headrest 18 and the front connecting portion 34B become a generally "U"-shaped structure that opens rearward when viewed from above (see FIG. 1 ). Figure 3 ).

[0065] In addition, after the airbag body 40 moves forward as the pair of front and rear chambers 34 expand and deploy, gas is supplied from the front and rear chambers 34 to expand and deploy toward the rear side (the passenger D side). That is, when the pair of front and rear chambers 34 expand and deploy, the airbag body 40 remains in a rolled-up state and passes through the head H of the passenger D and the ceiling 28 of the vehicle from the rear side to the front side (see FIG. Figure 12 to Figure 14 ) between the narrow gaps.

[0066] The airbag body 40 is inflated and deployed toward the occupant D side (rear side) at a delay relative to the pair of front and rear chambers 34 at the rear side of the front connecting portion 34B, and the inflated and deployed airbag body 40 is opposed to the head H, chest C and abdomen B of the occupant D with a gap in the front-rear direction (see FIG. Figures 1 to 3 ). In addition, the shape of the airbag body 40 when inflated and deployed is set so that it is sandwiched between the thigh F and chest C of the occupant D from the middle to the late stage of the occupant restraint.

[0067] In addition, if Figures 1 to 3As shown in FIG. 1 , a pair of left and right rear tethers 54, a pair of left and right front upper tethers 56, and a pair of left and right front lower tethers 58 are mounted on the airbag 32. The rear tethers 54, the front upper tethers 56, and the front lower tethers 58 are formed of, for example, polyamide or polyester fabrics in the form of long strips. In addition, the fabrics forming the rear tethers 54, the front upper tethers 56, and the front lower tethers 58 are formed in a manner that is difficult to stretch compared to the base fabric forming the front and rear chambers 34. The difficulty of stretching is adjusted by the material and thickness of the fabrics.

[0068] The pair of front upper tethers 56 are respectively connected to the left and right wall surfaces at the front side of the upper portion of the airbag body 40 that expands and deploys upward compared to the front and rear chambers 34, and the front portions of the pair of front and rear extensions 34A. That is, one end portion of each pair of front upper tethers 56 is sewn to the left and right wall surfaces at the front side of the upper portion of the airbag body 40 that expands and deploys upward compared to the front and rear chambers 34. And the other end portions of each pair of front upper tethers 56 are respectively sewn to the front portions of the pair of front and rear extensions 34A.

[0069] The pair of front lower tethers 58 are structured to connect the left and right wall surfaces at the front side of the lower portion of the airbag body 40 that expands and deploys downwardly compared to the front and rear chambers 34, and the front portions of the pair of front and rear extensions 34A. That is, one end portion of each pair of front lower tethers 58 is sewn to the left and right wall surfaces of the lower portion of the airbag body 40 that expands and deploys downwardly compared to the front and rear chambers 34. And the other end portions of each pair of front lower tethers 58 are sewn to the front portions of the pair of front and rear extensions 34A.

[0070] On the other hand, one end of each of the pair of rear tethers 54 is sewn and attached to the lower surface of the front portion of the front and rear chamber 34 (front and rear extension 34A) which is opposite to the substantially center portion of the inflated and deployed airbag body 40 in the side view in the seat width direction. And the other end of each of the pair of rear tethers 54 is attached to the side portion of the seat back 16 (or the vehicle body (not shown) which is on the rear side relative to the occupant D). Therefore, in the inflated and deployed state of the airbag 32, the pair of rear tethers 54 extend obliquely rearward and downward at the lower side of the pair of front and rear extensions 34A.

[0071] That is, the pair of rear tethers 54 are inclined toward the oblique rear lower side when viewed from the side. Therefore, when the occupant D is restrained by the airbag 32, the airbag body 40 is relatively pulled toward the oblique rear lower side (stretched) by the pair of rear tethers 54, and the front portions of the airbag body 40 and the pair of front and rear extensions 34A are relatively pulled toward the oblique rear lower side with the headrest 18 as the rotation center when viewed from the side.

[0072] Next, the operation of the airbag device 30 according to the first embodiment having the above-described structure will be described.

[0073] The airbag 32 having a pair of front and rear chambers 34 and an airbag body 40 is stored in the headrest 18 by bending the pair of front and rear chambers 34 at both ends in the seat width direction downwardly in a manner along the outer shape of the headrest 18 of the vehicle seat 12 in a front view. That is, the airbag 32 is compactly stored inside the headrest 18.

[0074] Furthermore, the headrest 18 storing the airbag 32 is formed integrally with the seat back 16. Therefore, compared with a case where the headrest 18 and the seat back 16 are separate bodies, it is possible to prevent the airbag 32 (airbag device 30) from detaching from the vehicle seat 12.

[0075] When the collision sensor detects (or predicts) a frontal collision of the vehicle, the inflator 44 operates under the control of the control device. That is, gas is generated and ejected from the inflator 44. The gas ejected from the inflator 44 passes through the distribution pipe 50 and is supplied to the pair of front and rear chambers 34 and the rear connecting portion 34C of the airbag 32.

[0076] Then, the tear line of the headrest 18 is ruptured by the expansion pressure of the pair of front and rear chambers 34 and the expansion pressure of the rear connecting portion 34C via the airbag body 40, that is, the pressing force of the expanded rear connecting portion 34C on the airbag body 40 folded in a roll toward the front side.

[0077] Here, the pair of front and rear chambers 34 accommodated in the headrest 18 are arranged to be bent downward relative to the airbag body 40 folded in a roll-like state when viewed from the front. Furthermore, each of the ejection ports 46A in the left and right branch pipes 46 of the distribution pipe 50 for supplying the gas ejected from the inflator 44 to the pair of front and rear chambers 34 extends forward and upward at a predetermined angle and a predetermined length when viewed from the side, and is located at the substantially central portion in the vertical direction at the rear side of the pair of front and rear chambers 34.

[0078] Therefore, when the expansion and deployment of a pair of front and rear chambers 34 that have begun to spray gas from each outlet 46A begins, the approximately central portion in the vertical direction at the rear side of the pair of front and rear chambers 34 can be effectively pushed forward, thereby stabilizing the deployment direction of the pair of front and rear chambers 34.

[0079] For example, when each of the ejection ports 46A in the left and right branch pipes 46 of the distribution pipe 50 that supplies the gas ejected from the inflation device 44 to the pair of front and rear chambers 34 is located at the lower end portion on the rear side of the pair of front and rear chambers 34 when viewed from the side, when the pair of front and rear chambers 34 start to expand and deploy, the pair of front and rear chambers 34 will tilt backward, making it difficult to push the pair of front and rear chambers 34 toward the front side.

[0080] In contrast, in the present embodiment, since the above-described structure is adopted, the unfavorable situation that the pair of front and rear chambers 34 tilt backward does not occur, and the deployment direction of the pair of front and rear chambers 34 is stabilized. Fig.12 As shown, the pair of front and rear chambers 34 expand and expand from the front surface of the headrest 18 through the left and right sides of the head H of the occupant D toward the front side.

[0081] In addition, this can stabilize the deployment of the airbag body 40 that moves with the expansion and deployment of the pair of front and rear chambers 34. Therefore, the airbag body 40 folded in a roll-like state can move forward through the upper side of the head H of the occupant D, that is, the narrow gap between the head H of the occupant D and the ceiling 28 of the vehicle cabin, as the pair of front and rear chambers 34 expand and deploy.

[0082] In this way, when the pair of front and rear chambers 34 are expanded and deployed, and the airbag body 40 in a state of being folded into a roll-like shape moves forward, as shown in FIG. Fig.13 As shown, the head H of the occupant D is relatively inserted into a gap portion surrounded by the front-rear extending portions 34A of the pair of front-rear chambers 34 and the airbag body 40 in a state of being folded into a roll shape.

[0083] Moreover, if Fig.14 As shown, the airbag body 40 is inflated and deployed toward the occupant D by supplying gas from the front side connecting portion 34B that connects the front end portions of the front and rear extending portions 34A of the pair of front and rear chambers 34 in the left-right direction through the communication hole. That is, the airbag body 40 is arranged between the pair of front and rear chambers 34 and on the front side of the occupant D.

[0084] In this way, after the inflation and deployment of the front and rear chambers 34 are completed, the gas from the inflator 44 is supplied to the airbag body 40 through the communication hole of the front-side connecting portion 34B. In other words, the gas ejected from the inflator 44 and flowing through the pair of front and rear extensions 34A and the front-side connecting portion 34B of the front and rear chambers 34 is supplied to the airbag body 40 through the communication hole. Therefore, the airbag body 40 can be inflated and deployed with sufficient delay relative to the pair of front and rear chambers 34.

[0085] Thus, the airbag body 40 can be made to reliably and easily pass through the narrow gap between the head H of the occupant D and the ceiling 28 of the vehicle compartment from the rear side to the front side while being folded into a roll shape as the pair of front and rear chambers 34 expand and expand. Therefore, the occurrence of an inconvenience such as the airbag body 40 getting stuck in the narrow gap can be prevented, and the occurrence of an inconvenience in the deployment of the airbag 32 can be suppressed or prevented.

[0086] Furthermore, in the present embodiment, since the distribution pipe 50 is provided inside the headrest 18, there is no restriction on the mounting position of the inflator 44. Therefore, for example, the inflator 44 can be provided inside the seat back 16 along the extending direction of the seat back 16 (with the axial direction oriented in the up-down direction) or can be provided from the inside of the seat back 16 to the inside of the headrest 18, thereby suppressing the increase in size (increase in thickness) of the seat back 16 and the headrest 18.

[0087] Furthermore, when the airbag body 40 is inflated and deployed, the pair of front upper tethers 56 connect the left and right sides of the front side of the upper portion of the airbag body 40 and the front portions of the pair of front and rear extensions 34A, respectively. By means of the pair of front upper tethers 56, when the inflation and deployment of the airbag body 40 (airbag 32) is completed, it is possible to suppress the airbag body 40 from being inadvertently displaced (rotated) upward about the front side connection portion 34B relative to the front and rear chambers 34.

[0088] Furthermore, when the airbag body 40 is inflated and deployed, the pair of front lower tethers 58 connect the left and right sides of the front side of the lower portion of the airbag body 40 and the front portions of the pair of front and rear extensions 34A, respectively. By means of the pair of front lower tethers 58, when the inflation and deployment of the airbag body 40 (airbag 32) is completed, it is possible to suppress the airbag body 40 from being inadvertently displaced (rotated) downwardly about the front side connection portion 34B relative to the front and rear chambers 34.

[0089] Furthermore, when the inflation and deployment of the airbag 32 is completed, the pair of rear tethers 54 extend obliquely rearward and downward at the lower side of the pair of front-rear extensions 34A. That is, the pair of rear tethers 54 restrict the movement of the airbag body 40 obliquely forward and upward. Thus, the swing of the airbag 32 in the vertical direction and the front-rear direction can be suppressed (which can contribute to the stabilization of the deployment operation of the airbag body 40).

[0090] In this state, the occupant D who has inertially moved forward due to the impact of the frontal collision of the vehicle is restrained by the airbag body 40. Specifically, when restraining the occupant D, the front and rear chambers 34 (front and rear extensions 34A) move forward of the occupant D and extend forward of the occupant D. Furthermore, the airbag body 40 is pressed forward by the occupant D and is compressed and deformed forward of the occupant D.

[0091] Therefore, the energy absorption performance of the airbag body 40 can be improved, and its occupant restraint performance can be effectively ensured. That is, when both the front and rear chambers 34 and the airbag body 40 are subjected to tensile loads, although the load applied to the occupant D from the airbag body 40 increases, the load applied to the occupant D can be reduced by the compression deformation of the airbag body 40.

[0092] Furthermore, since the airbag body 40 is shaped so as to be sandwiched between the thigh F and the chest C of the occupant D from the middle to the late stage of restraining the occupant by the airbag 32, it can contact the upper body of the occupant D over a wide area. As a result, the load applied to the occupant D from the airbag body 40 can be reduced well.

[0093] Furthermore, since the airbag body 40 is inflated and deployed toward the occupant D at the rear side of the front connecting portion 34B after the front and rear chambers 34 are inflated and deployed, the gap between the airbag body 40 and the occupant D becomes smaller. As a result, the occupant D is restrained at an early stage by the airbag body 40, and the initial restraint performance of the occupant D by the airbag body 40 can be improved.

[0094] Furthermore, since the pair of rear tethers 54 are less likely to extend than the front and rear chambers 34, the airbag body 40 is relatively pulled obliquely rearward and downward by the pair of rear tethers 54 when restraining the occupant D. Thus, when restraining the occupant, the position of the airbag body 40 in the vertical direction relative to the head H of the occupant D can be stabilized. That is, according to the airbag 32, the occupant D can be appropriately restrained.

[0095] <Second Embodiment>

[0096] Next, an airbag device 30 according to a second embodiment will be described. The same reference numerals are used for the same parts as those in the first embodiment, and detailed descriptions thereof (including common operations) will be appropriately omitted.

[0097] like Fig.15AAs shown, in the airbag device 30 involved in the second embodiment, the left root 36L and the right root 36R (only the left root 36L is shown in FIG15 ) of a pair of front and rear chambers 34 respectively connected to the respective ejection ports 46A in the left branch pipe 46L and the right branch pipe 46R (only the left branch pipe 46L is shown in FIG15 ) of the distribution pipe 50 are stored in the headrest 18 in a state of being bent into an upward convex shape (a roughly circular arc shape convex toward the upper side) when observed from the side, which is different from the above-mentioned first embodiment.

[0098] In this way, when the left and right root portions 36L and 36R of a pair of front and rear chambers 34 connected to the respective ejection ports 46A in the left and right branch pipes 46L and 46R of the distribution pipe 50 are stored in a state bent into an upward convex shape when viewed from the side, as shown in FIG. Fig. 15B As shown, by supplying gas from each ejection port 46A, the left and right root portions 36L and 36R expand and expand, and the expanded and expanded left and right root portions 36L and 36R can press the upper portion of the rear side of the pair of front and rear chambers 34 toward the front and lower side.

[0099] Furthermore, since gas is supplied (injected) from the rear upper side toward the front lower side in the side view to the substantially vertical center portion of the rear side of the pair of front and rear chambers 34 through the expanded and deployed left and right root portions 36L and 36R, the pair of front and rear chambers 34 can be pushed toward the front lower side more effectively. Therefore, the deployment direction of the pair of front and rear chambers 34 can be stabilized more effectively.

[0100] The airbag device 30 attached to the seat involved in the present embodiment has been described above based on the drawings, but the airbag device 30 attached to the seat involved in the present embodiment is not limited to the device shown in the drawings, and the design can be appropriately changed within the scope of the main purpose of the present disclosure.

[0101] For example, the distribution pipe 50 may be provided across the inside of the headrest 18 and the inside of the seat back 16. In addition, although the root portions 36 and 38 are shown inserted into the inner side of the ejection ports 46A and 48A for installation, the present invention is not limited thereto, and the root portions 36 and 38 may be provided to cover the outer side of the ejection ports 46A and 48A for installation.

[0102] Although not shown in the figure, the distribution pipe 50 may not be provided inside the headrest 18, but the respective ejection ports 44A of the three inflators 44 may be directly connected to the respective root portions 36L, 36R, 38. In this case, although the thickness of the headrest 18 increases because the respective inflators 44 protrude obliquely toward the rear lower side, the same effect as described above can be obtained even if the respective ejection ports 44A of the two inflators 44 directly connected to the left and right root portions 36L, 36R are respectively located at the substantially central portion in the vertical direction at the rear side of the pair of front and rear chambers 34.

Claims

1. An airbag device attached to a seat, comprising: An inflator that is provided on a vehicle seat and ejects gas when the vehicle collides; The airbag comprises an airbag body and a pair of front and rear chambers, wherein the pair of front and rear chambers are supplied with gas ejected from the inflator so as to expand and deploy toward the front side of the seat through the left and right sides of the head of an occupant seated on the vehicle seat, and the airbag body moves toward the front side of the seat through between the head of the occupant and the ceiling of the vehicle compartment as the pair of front and rear chambers expand and deploy, and the airbag body is supplied with the gas from the pair of front and rear chambers so as to expand and deploy toward the rear side of the seat between the pair of front and rear chambers, and is arranged at the front side of the seat of the occupant, The pair of front and rear chambers are bent toward the lower side of the seat relative to the airbag body and accommodated in the headrest of the vehicle seat when the airbag is viewed from the front side of the seat, and The gas ejected from the inflator is disposed at a vertically central portion of the pair of front and rear chambers on the seat rear side when viewed from the side in the seat width direction.

2. The seat-attached airbag device according to claim 1, wherein: A distribution pipe is provided on the vehicle seat and is capable of supplying the gas ejected from the inflator to the pair of front and rear chambers, respectively. The distribution pipe has a spray outlet connected to the root of the pair of front and rear chambers respectively. The spray port extends to an upper front side of the seat by a predetermined length when viewed from the side in the seat width direction, and is located at a center portion in the up-down direction of the pair of front and rear chambers on the seat rear side.

3. The seat-attached airbag device according to claim 1 or 2, wherein: The bases of the pair of front and rear chambers connected to the spray port are accommodated in the headrest in a state of being bent into an upward convex shape in a side view as seen in the seat width direction.

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