Overhead airbag device and occupant restraint device

Abstract

The invention discloses an overhead airbag device and an occupant restraint device. An overhead airbag device is provided with: an airbag mounted on the upper side of a ceiling of a vehicle cabin, the airbag having a first chamber that cracks the ceiling and inflates and deploys toward the vehicle front side of an occupant seated in a vehicle seat by being supplied with gas from an inflator during a frontal collision of the vehicle, and a second chamber that expands and deploys toward the vehicle front side of the occupant seated in the vehicle seat by being supplied with gas from an inflator; the second chamber is inflated and deployed toward the occupant by being supplied with the gas from the first chamber; and a pulling member that connects the first chamber and a support part provided on the upper side of the ceiling, and that cracks and deploys the ceiling as the first chamber expands and deploys, and that pulls the ceiling when the occupant moving toward the front side of the vehicle due to inertia force is restrained by the second chamber. The pulling member relatively pulls the first chamber toward the rear side of the vehicle and toward the upper side of the vehicle.

Description

Technical Field

[0001] The present disclosure relates to a roof-mounted airbag device and an occupant restraint device. Background Art

[0002] An occupant protection device having an airbag formed by a single chamber and arranged in front of the occupant when the vehicle is deployed downward from the roof of the vehicle in the event of a head-on collision, and a tether connecting the lower end of the airbag to the ceiling behind the airbag storage portion is previously known (for example, refer to Japanese Patent Gazette No. 2018-161965).

[0003] In addition, an occupant protection device that includes an airbag formed by a single chamber that is stored on the roof side of a vehicle and deploys downward to receive the head of an occupant when the vehicle collides head-on, and a connecting part that connects the two side surfaces of the lower end of the airbag to the roof rearward of the storage portion of the airbag is also previously known (for example, refer to Japanese Patent Gazette No. 2021-054100). Summary of the invention

[0004] However, the relative positional relationship in the front-rear direction between the airbag that is deployed downward from the ceiling and disposed in front of the occupant and the occupant (upper body including the head) changes depending on the front-rear position of the vehicle seat.

[0005] Therefore, depending on the front-rear position of the vehicle seat, there is a possibility that sufficient occupant restraint performance cannot be obtained (the occupant is not restrained effectively) by the airbag.

[0006] Therefore, the present disclosure provides a ceiling-mounted airbag device that can effectively restrain an occupant regardless of the front-rear position of a vehicle seat, and an occupant restraint device including the ceiling-mounted airbag device.

[0007] The first scheme of the present disclosure relates to a ceiling-mounted airbag device comprising: an airbag mounted on the upper side of a ceiling of a vehicle cabin, having a first chamber and a second chamber, wherein, in a frontal collision of a vehicle, the first chamber is supplied with gas from an inflator so as to cause the ceiling to rupture and expand and deploy toward the vehicle front side of a passenger seated on a vehicle seat (is configured to be expanded and deployed), and the second chamber is supplied with the gas from the first chamber so as to expand and deploy toward the passenger (is configured to be expanded and deployed); and a pulling member connecting the first chamber to a support portion provided on the upper side of the vehicle ceiling, and causing the ceiling to rupture and expand in association with the expansion and deployment of the first chamber, and when the passenger who is about to move toward the vehicle front side due to inertia force is restrained by the second chamber, the pulling member relatively pulls the first chamber toward the vehicle rear side and the vehicle upper side.

[0008] According to the disclosure of the first scheme, when the vehicle collides head-on, the first chamber of the airbag is supplied with gas from the inflator, so that the ceiling of the vehicle compartment is cracked and expanded and deployed toward the front side of the vehicle of the occupant seated on the vehicle seat. Moreover, the second chamber of the airbag is supplied with gas from the first chamber, so that the second chamber of the airbag is expanded and deployed from the first chamber toward the occupant. And, accompanying the expansion and deployment of the first chamber, a pulling component connecting the first chamber and a support portion provided on the upper side of the ceiling of the vehicle causes the ceiling to crack and deploy, and when the occupant who is about to move toward the front side of the vehicle due to inertia is restrained by the second chamber, the pulling component pulls the first chamber relatively toward the rear side of the vehicle and the upper side of the vehicle.

[0009] Therefore, the load from the occupant who moves toward the front side of the vehicle due to inertia is effectively borne by the second chamber that is relatively pulled toward the rear side and the upper side of the vehicle via the first chamber by the pulled component. That is, when the airbag restrains the occupant, even if the second chamber is pressed toward the front side of the vehicle by the occupant, a reaction force is obtained by the first chamber pulled by the pulled component, and therefore, the occupant is effectively restrained by the compression deformation of the second chamber. Therefore, compared with the top-mounted airbag formed by a single chamber, it is easy to cope with the change in the distance between the occupant and the airbag caused by the change in the front and rear position of the vehicle seat, and the area in which the occupant restraint performance (occupant protection performance) is obtained is expanded. In this way, according to the present disclosure, the occupant is effectively restrained regardless of the front and rear position of the vehicle seat. In addition, the "frontal collision" mentioned here also includes the time when the frontal collision is predicted (foreseen) to be inevitable.

[0010] A ceiling-mounted airbag device according to a second aspect of the present disclosure is the ceiling-mounted airbag device according to the first aspect, wherein the pulling member is formed of a planar tether covering at least an upper half of the inflated and deployed second chamber in a side view.

[0011] According to the disclosure of the second solution, the pulling member is composed of a planar tether that covers at least the upper half of the second chamber after expansion and deployment in a side view. Therefore, compared with the case where the pulling member is composed of a pair of left and right belt-like tethers that only cover the lower end of the second chamber after expansion and deployment in a side view, it is possible to prevent the occurrence of an undesirable situation such as the neck of the occupant being caught on the belt-like tether.

[0012] The third scheme of the ceiling-mounted airbag device involved in the present disclosure is based on the ceiling-mounted airbag device of the first or second scheme, wherein the second chamber is formed into the following structure: it is arranged on the lower side of the vehicle than the center part of the first chamber in the vehicle vertical direction and can restrain at least the head and chest of the above-mentioned occupant.

[0013] According to the disclosure of the third scheme, the second chamber is formed into the following structure: it is arranged at the lower side of the vehicle than the central part of the first chamber in the vehicle vertical direction and can restrain at least the head and chest of the occupant. Therefore, compared with a ceiling-mounted airbag formed by a single chamber that covers at least from the ceiling to the chest of the occupant, the increase in the capacity of the airbag (the first chamber and the second chamber) is suppressed. In other words, the increase in the output of the inflator is suppressed, and the manufacturing cost is reduced accordingly. In addition, since at least the head and chest of the occupant are restrained by the compression deformation of the second chamber, the occupant's neck flexion will not increase.

[0014] The fourth scheme of the overhead airbag device involved in the present disclosure is based on the overhead airbag device of any one of the first to third schemes. A limiting tether that limits the length of the second chamber to be deployed along the front-rear direction of the vehicle is provided inside the second chamber, and the limiting tether is formed into the following structure: the restriction is released when the vehicle seat is located above a predetermined position on the rear side of the vehicle.

[0015] According to the disclosure of the fourth scheme, the limiting tether provided inside the second chamber in order to limit the length (thickness) of the second chamber to be expanded along the front-rear direction of the vehicle is formed into the following structure: when the vehicle seat is located above the predetermined position on the rear side of the vehicle, the restriction is released. Therefore, when the vehicle seat is located closer to the front side of the vehicle than the predetermined position, the occupant is restrained by the second chamber whose thickness is limited by the limiting tether. And, when the vehicle seat is located above the predetermined position on the rear side of the vehicle, the occupant is restrained by the second chamber whose expansion toward the rear side of the vehicle is released. That is, even when the vehicle seat is located above the predetermined position on the rear side of the vehicle, the occupant is effectively and appropriately restrained compared to a ceiling-mounted airbag formed by a single chamber.

[0016] A ceiling-mounted airbag device according to a fifth aspect of the present disclosure is the ceiling-mounted airbag device according to the fourth aspect, wherein the restriction tether is configured such that the restriction is released by being cut.

[0017] According to the disclosure of the fifth aspect, the restriction tether is formed into a structure in which the restriction is released by breaking. Therefore, the structure of the restriction tether can be simpler than a structure in which the restriction is released by detaching one end of the restriction tether.

[0018] The sixth scheme of the ceiling-mounted airbag device involved in the present disclosure is based on the ceiling-mounted airbag device of the fifth scheme, wherein the above-mentioned inflator is capable of changing the output of the above-mentioned inflator based on the detection result of the front-rear position of the above-mentioned vehicle seat, and the above-mentioned limiting tether is configured to be cut by increasing the output of the above-mentioned inflator.

[0019] According to the sixth aspect, the restriction tether is disconnected by increasing the output of the inflator configured to change its output based on the detection result of the front-rear position of the vehicle seat. Therefore, the structure can be simpler than, for example, a separate mechanism for disconnecting the restriction tether is provided.

[0020] An occupant restraint device according to a seventh aspect of the present disclosure is provided with a ceiling-mounted airbag device according to any one of the first to sixth aspects for each vehicle seat.

[0021] According to the disclosure of the seventh aspect, since the ceiling-mounted airbag device according to any one of the first to sixth aspects is provided for each vehicle seat, the occupant can be effectively and appropriately restrained according to the front-rear position of each vehicle seat.

[0022] An occupant restraint device according to an eighth aspect of the present disclosure is configured such that a ceiling-mounted airbag device according to any one of the first to sixth aspects is provided for the entirety of the left and right adjacent vehicle seats.

[0023] According to the disclosure of the eighth aspect, since one overhead airbag device according to any one of the first to sixth aspects is provided for the entirety of the left and right adjacent vehicle seats, the number of components can be reduced and the manufacturing cost can be reduced.

[0024] In addition, a occupant restraint device according to a ninth aspect of the present disclosure is the occupant restraint device according to the eighth aspect, wherein one first chamber is provided for all of the left and right adjacent vehicle seats, and each of the left and right adjacent vehicle seats is provided with the second chamber.

[0025] According to the disclosure of the ninth scheme, a first chamber is provided for the entirety of the left and right adjacent vehicle seats, and a second chamber is provided for each of the left and right adjacent vehicle seats. Therefore, the number of components can be reduced (manufacturing cost can be reduced), and the occupants can be effectively and appropriately restrained according to the front and rear positions of each vehicle seat.

[0026] Effects of the Invention

[0027] As described above, according to the present disclosure, it is possible to effectively restrain an occupant regardless of the front-rear position of the vehicle seat. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic side view showing a state in which the ceiling-mounted airbag device according to the first embodiment is mounted on the upper side of the ceiling of the vehicle interior.

[0029] Figure 2 It is a schematic side view showing a state in the initial stage of inflation and deployment of the airbag of the ceiling-mounted airbag device according to the first embodiment.

[0030] Figure 3This is a schematic side view showing a state in a late stage of inflation and deployment of the airbag of the ceiling-mounted airbag device according to the first embodiment.

[0031] Figure 4A It is a schematic plan view showing the inflation and deployment process of the airbag of the ceiling-mounted airbag device according to the first embodiment.

[0032] Figure 4B It is a schematic plan view showing the inflation and deployment process of the airbag of the ceiling-mounted airbag device according to the first embodiment.

[0033] Figure 4C It is a schematic plan view showing the inflation and deployment process of the airbag of the ceiling-mounted airbag device according to the first embodiment.

[0034] Figure 5 It is a schematic side view showing a state in the initial stage of inflation and deployment of an airbag of a ceiling-mounted airbag device according to a second embodiment.

[0035] Figure 6 This is a schematic side view showing a state of the ceiling-mounted airbag device according to the second embodiment in a late stage of inflation and deployment of the airbag when the vehicle seat is located forward of a predetermined position.

[0036] Figure 7 This is a schematic side view showing a state of the ceiling-mounted airbag device according to the second embodiment in a late stage of inflation and deployment of the airbag when the vehicle seat is located above a predetermined rearward position.

[0037] Fig. 8A It is a schematic plan view showing an inflation and deployment process of an airbag of a ceiling-mounted airbag device according to the third embodiment provided for each of the left and right adjacent vehicle seats.

[0038] Figure 8B It is a schematic plan view showing an inflation and deployment process of an airbag of a ceiling-mounted airbag device according to the third embodiment provided for each of the left and right adjacent vehicle seats.

[0039] Figure 8C It is a schematic plan view showing an inflation and deployment process of an airbag of a ceiling-mounted airbag device according to the third embodiment provided for each of the left and right adjacent vehicle seats.

[0040] Fig.9A This is a schematic plan view showing an inflation and deployment process of a second chamber in an airbag of a ceiling-mounted airbag device according to a third embodiment provided for each of the vehicle seats adjacent to each other on the left and right.

[0041] Fig. 9BThis is a schematic plan view showing an inflation and deployment process of a second chamber in an airbag of a ceiling-mounted airbag device according to a third embodiment provided for each of the vehicle seats adjacent to each other on the left and right.

[0042] Fig. 9C This is a schematic plan view showing an inflation and deployment process of a second chamber in an airbag of a ceiling-mounted airbag device according to a third embodiment provided for each of the vehicle seats adjacent to each other on the left and right. DETAILED DESCRIPTION

[0043] Hereinafter, the embodiments of the present disclosure will be described in detail based on the accompanying drawings. In addition, for the sake of convenience, the arrow UP appropriately shown in each figure is set as the upward direction of the vehicle and the vehicle seat, the arrow FR is set as the front direction of the vehicle and the vehicle seat, and the arrow RH is set as the right direction of the vehicle and the vehicle seat. Therefore, in the following description, when the up-down, front-back, left-right directions are not specifically described, the up-down, front-back, left-right directions of the vehicle and the vehicle seat are indicated. In addition, the left-right direction is synonymous with the vehicle width direction and the seat width direction.

[0044] <First Embodiment>

[0045] First, the first embodiment will be described. Figure 1 As shown in FIG. 4 , the occupant restraint device 10 is composed of a vehicle seat 12 and a ceiling-mounted airbag device 30 (hereinafter, sometimes simply referred to as “airbag device 30 ”) provided for each vehicle seat 12 .

[0046] The vehicle seat 12 is a front seat or a rear seat of a vehicle such as an autonomous vehicle, which can enlarge the front side of the seat in the front-rear direction. The vehicle seat 12 includes a seat cushion 14 for a passenger to sit on (supporting the buttocks and thighs of the passenger), a seat back 16 which is arranged on the rear side of the seat cushion 14 in a manner that can rotate with the seat width direction as an axial direction and supports the back of the passenger, and a headrest 18 which is arranged at the upper end of the seat back 16 in a manner that can be raised and lowered and supports the head of the passenger.

[0047] In addition, in each figure, as a model of the occupant (seat occupant) to be protected, a state in which a dummy (human model) for a collision test is seated on the seat cushion 14 of the vehicle seat 12 is shown. The dummy is, for example, an AM50 (50th percentile of American adult males) dummy for a frontal collision test (Hybrid III). The dummy is seated in a standard seating posture prescribed by the collision test law, and the vehicle seat 12 is located at a reference setting position corresponding to the seating posture. Hereinafter, the dummy is referred to as "occupant P".

[0048] The occupant P sitting on the seat cushion 14 of the vehicle seat 12 is restrained to the vehicle seat 12 by a seat belt provided in a seat belt device (not shown). The seat belt device is a three-point seat belt device.

[0049] An airbag device 30 is mounted on the upper side of the ceiling (roof headliner) 20 of the vehicle compartment in front of the vehicle seat 12. The airbag device 30 includes an airbag 32, an inflator 28, and a module box 26. The airbag 32 is normally stored in the module box 26 in a folded state together with the inflator 28. The module box 26 is formed in a hollow, substantially rectangular parallelepiped shape and is disposed on the upper side of the ceiling 20 of the vehicle compartment. In addition, the module box 26 may also be disposed on the lower side of a roof panel (between the roof headliner and the roof panel) not shown in the figure.

[0050] The vehicle is provided with a control device (ECU) for controlling the operation of the inflator 28. The control device is electrically connected to the inflator 28 and a collision sensor (including a camera, etc.) not shown in the figure, and is configured to detect a frontal collision of the vehicle or predict (foresee) 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 (hereinafter referred to as "frontal collision"), the inflator 28 is operated.

[0051] The inflator 28 is a substantially cylindrical cylinder-type inflator of a combustion type or a cold air type, and is arranged with its axial direction along the front-rear direction. In addition, the inflator 28 is operated by the control device when the vehicle collides head-on, thereby generating gas. In addition, the frontal collision of the vehicle in which the control device operates the inflator 28 includes not only a full overlap frontal collision but also an offset frontal collision such as an oblique collision and a small overlap collision.

[0052] The airbag 32 uses the inflation pressure formed by the gas supplied from the inflator 28 to rupture the ceiling 20 and deploy and expand toward the front side of the occupant P sitting on the vehicle seat 12. In addition, a tear line (not shown) as a rupture portion for rupture is formed in the ceiling 20, and the airbag 32 ruptures the tear line to expand and deploy. In addition, the portion that ruptures and retracts from the tear line serves as an airbag door (not shown).

[0053] The airbag 32 includes a first chamber 34 and a second chamber 36. In the airbag 32, by first supplying gas from the inflator 28 to the first chamber 34, the first chamber 34 breaks the tear line formed in the ceiling 20 and expands and deploys toward the lower side, and is arranged at the front side that is more than a predetermined distance away from the occupant P sitting on the vehicle seat 12. In addition, the first chamber 34 after expansion and expansion has a structure in which the length in the front-to-back direction is shorter than that of the second chamber 36 after expansion and expansion (the thickness is thinner than that of the second chamber 36 after expansion and expansion).

[0054] The second chamber 36 is provided via the communication hole 35 so as to reach the lower side than the vertical center of the rear wall 34B of the inflated and deployed first chamber 34, and gas is supplied from the first chamber 34 through the communication hole 35. That is, the second chamber 36 is configured to inflate and deploy toward the occupant P (rear side) at a predetermined delay relative to the first chamber 34. And, the inflated and deployed second chamber 36 is arranged at least in front of the head and chest of the occupant P.

[0055] In addition, the communication hole 35 is provided at the substantially central part in the vertical direction and the substantially central part in the horizontal direction of the second chamber 36. In addition, the inflated and deployed second chamber 36 is formed to have a height, width, and thickness that can restrain at least the head and chest of the occupant P (not only the head of the occupant P but also the chest) that are intended to move forward due to the inertial force in the event of a frontal collision of the vehicle, and can be compressed and deformed by being pressed by at least the head and chest of the occupant P (see Figure 3 ).

[0056] The first chamber 34 and the second chamber 36 are each formed into a bag shape by overlapping two base fabrics and sewing their peripheral edges. The base fabric is made of, for example, a polyamide or polyester fabric. The front wall 36F of the second chamber 36 is attached to the rear wall 34B of the first chamber 34 by sewing the peripheries of the communicating hole 35 formed in, for example, a circular shape.

[0057] In addition, a planar tether 38 serving as a pulling member is provided on the upper side of the ceiling 20. The planar tether 38 expands toward the lower side as the first chamber 34 expands and expands, thereby splitting a tear line (not shown) formed on the ceiling 20, thereby connecting the expanded and expanded first chamber 34 and a pair of support portions 22 provided on the upper side of the ceiling 20 at a predetermined length or more to the rear of the module box 26.

[0058] The planar tether 38 is configured such that when at least the head and chest of the occupant P that is moving forward due to inertial force are restrained by the second chamber 36, the first chamber 34 is relatively pulled obliquely to the rear upper side, that is, to the rear and upper side. In other words, the second chamber 36 is configured to receive a reaction force from the front side through the first chamber 34 pulled by the planar tether 38.

[0059] In addition, the planar tether 38 after deployment is formed to a size that can cover at least the left and right sides of the head and neck of the occupant P when the inflated and deployed second chamber 36 restrains at least the head and chest of the occupant P in a side view as viewed from the vehicle width direction. In other words, the planar tether 38 is formed to a size that covers at least the upper half of the inflated and deployed second chamber 36 in a side view, and its upper edge portion 38U is located above the upper end surface 36U of the inflated and deployed second chamber 36 (see FIG. 1 ). Figure 3 ).

[0060] The planar tether 38 is formed to a size that substantially covers the entire front wall 34F of the first chamber 34 and is attached to the first chamber 34 (airbag 32 ) by being sewn to the first chamber 34 around an overlapping region so as to cover the front wall 34F of the first chamber 34 .

[0061] In addition, the planar tether 38 is formed into a substantially right triangle shape with a right angle at the top of the front end in a side view in order to facilitate the efficient pulling of the first chamber 34 toward the upper side obliquely rearward. In other words, the planar tether 38 is formed into a substantially obtuse isosceles triangle shape in a front view from a single piece of cloth material such as polyamide or polyester.

[0062] Next, the operation of the ceiling-mounted airbag device 30 and the occupant restraint device 10 according to the first embodiment having the above-described configuration will be described.

[0063] When the vehicle collides head-on, the inflator 28 is operated under the control of the control device, and gas is ejected from the inflator 28. The gas ejected from the inflator 28 is supplied to the first chamber 34 of the airbag 32. Then, the tear line formed on the ceiling 20 of the vehicle compartment is ruptured by the inflation pressure of the first chamber 34, and the first chamber 34 of the airbag 32 is inflated and deployed downward.

[0064] That is, the first chamber 34 is inflated and deployed toward the front side that is away from the occupant P seated on the vehicle seat 12 by a predetermined length or more. Furthermore, by supplying gas from the first chamber 34 through the communication hole 35, the second chamber 36 is inflated and deployed toward the occupant P (rear side) at a predetermined delayed timing from the first chamber 34.

[0065] In addition, as the first chamber 34 expands and expands, the planar tether 38 connecting the expanded and expanded first chamber 34 and the pair of left and right support portions 22 provided on the upper side of the ceiling 20 breaks the tear line formed on the ceiling 20 and expands. Furthermore, when the planar tether 38 restrains at least the head and chest of the occupant P who is about to move forward due to the inertial force by the second chamber 36, the first chamber 34 is relatively pulled obliquely to the rear and upper side. That is, the planar tether 38 forms a reaction force surface with respect to the second chamber 36 together with the first chamber 34.

[0066] Therefore, the load from the occupant P moving forward due to the inertial force can be effectively received by the second chamber 36 relatively pulled obliquely rearward and upward by the planar tether 38 via the first chamber 34. That is, when restraining the occupant, even if the second chamber 36 is pressed forward by the occupant P, a reaction force can be obtained by the first chamber 34 pulled by the planar tether 38, so that the second chamber 36 can be compressed and deformed to restrain at least the head and chest of the occupant P.

[0067] Therefore, compared with a ceiling-mounted airbag (not shown) formed of a single chamber, it is easier to absorb the change in the distance between the occupant and the airbag caused by the change in the front-rear position of the vehicle seat 12, and the area of ​​the occupant restraint performance (occupant protection performance) can be expanded. In this way, according to the first embodiment, at least the head and chest of the occupant P that inertially moves to the front side due to the impact of the vehicle frontal collision can be effectively and appropriately restrained regardless of the front-rear position of the vehicle seat 12.

[0068] In addition, the pulling member that pulls the first chamber 34 obliquely rearward and upward is composed of a planar tether 38 that covers at least the upper half of the inflated and expanded second chamber 36 in a side view. Therefore, compared with a case where the pulling member is composed of, for example, a pair of left and right belt-like tethers (not shown) that connect the lower end of the inflated and expanded second chamber 36 and the support portion 22, it is possible to prevent the occurrence of an unfavorable situation in which the neck of the occupant P is hooked on the belt-like tether and injured.

[0069] In addition, the second chamber 36 is provided below the vertical center of the first chamber 34 and is configured to restrain at least the head and chest of the occupant P. Therefore, compared with a ceiling-mounted airbag (not shown) formed of a single chamber that covers at least from the ceiling to the chest of the occupant P, it is possible to suppress an increase in the volume of the airbag 32 (the first chamber 34 and the second chamber 36). In other words, it is possible to suppress an increase in the output of the inflator 28, and accordingly, it is possible to reduce the manufacturing cost.

[0070] In addition, the second chamber 36 contacts the upper body (at least the head and chest) of the occupant P with a large area, and not only the head but also the chest of the occupant P is restrained by the compression deformation of the second chamber 36, so that the energy absorption performance of the second chamber 36 can be improved, and the load applied from the second chamber 36 to the occupant P can be reduced. Therefore, the cervical flexion does not occur in the occupant P, and even if the cervical flexion occurs, the cervical flexion does not increase.

[0071] In addition, the second chamber 36 is inflated and deployed with a delay relative to the first chamber 34, so that the occurrence of poor deployment of the airbag 32 can be suppressed or prevented compared to the case where the second chamber 36 and the first chamber 34 simultaneously break the tear line of the ceiling 20 and inflate and deploy. In addition, the airbag device 30 is provided for each vehicle seat 12, so the occupant P can be effectively and appropriately restrained according to the front-rear position of each vehicle seat 12.

[0072] <Second Embodiment>

[0073] Next, a second embodiment will be described. Note that the same reference numerals are used for the same parts as those of the first embodiment, and detailed descriptions thereof will be appropriately omitted.

[0074] like Figure 5~Figure 7 As shown, in the second embodiment, the only difference from the first embodiment is that a single limiting tether 40 is provided inside the second chamber 36 to limit the length (thickness) of the second chamber 36 in the front-rear direction. The limiting tether 40 is formed in a belt shape having a predetermined thickness and width (length in the left-right direction), and its front end 40F is attached to the substantially central portion in the up-down direction and the substantially central portion in the left-right direction of the inner surface of the front wall 36F of the second chamber 36 by sewing, and its rear end 40B is attached to the substantially central portion in the up-down direction and the substantially central portion in the left-right direction of the inner surface of the rear wall 36B of the second chamber 36 by sewing.

[0075] In addition, the communication hole 35 shown in the figure is provided at the lower side of the restriction tether 40 in a side view, and the gas supplied from the communication hole 35 to the second chamber 36 flows to the upper side through the gaps on the left and right sides of the restriction tether 40, but the present invention is not limited thereto. The communication hole 35 may also be provided at the upper side of the restriction tether 40, and the gas supplied from the communication hole 35 to the second chamber 36 may also flow to the lower side through the gaps on the left and right sides of the restriction tether 40.

[0076] In addition, the restriction tether 40 is configured to release the restriction when the vehicle seat 12 is located above a predetermined position on the rear side. Specifically, the inflator 28 is configured to change its output based on the detection result of the front-rear position of the vehicle seat 12, and the restriction tether 40 is released by disconnecting the restriction tether 40 due to an increase in the output of the inflator 28.

[0077] The front-rear position of the vehicle seat 12 is detected by a seat slide sensor (not shown) provided in the vehicle, and the seat slide sensor is also electrically connected to a control device for controlling the operation of the inflator 28. The inflator 28 is a dual inflator, and is configured to be able to control the output in two stages.

[0078] Although not shown in the figure, the width of the predetermined portion of the restriction tether 40 is formed to be smaller than the width of other portions, and a cut groove such as a perforated line along the width direction is added to the predetermined portion, so that the predetermined portion is cut when the tension exceeds the predetermined value. Thus, the following structure is obtained: when the tension of the restriction tether 40 acting by the expansion of the second chamber 36 exceeds the predetermined value, it is automatically cut from the predetermined portion.

[0079] Next, the operation of the roof-mounted airbag device 30 and the occupant restraint device 10 according to the second embodiment having the above-described structure will be described. In addition, the description of the operation common to the first embodiment will be appropriately omitted.

[0080] As described above, the thickness (length in the front-rear direction) of the second chamber 36 is restricted by the restriction tether 40 provided inside the second chamber 36. Therefore, when the vehicle seat 12 is located on the front side of the predetermined position, at least the head and chest of the occupant P can be restrained by the second chamber 36 whose thickness is restricted by the restriction tether 40. That is, the occupant P who is inertially moved to the front side due to the impact of the frontal collision of the vehicle can be effectively and appropriately restrained.

[0081] On the other hand, when the vehicle seat 12 is located above the predetermined position on the rear side of the vehicle, the output of the inflator 28 increases, the restriction tether 40 is disconnected, and the restriction is released. Therefore, when the vehicle seat 12 is located above the predetermined position on the rear side, the restriction of the restriction tether 40 is released and the second chamber 36 expands to the rear side to restrain at least the head and chest of the occupant P. That is, even when the vehicle seat 12 is located above the predetermined position on the rear side, the occupant P who is inertially moved to the front side due to the impact of the frontal collision of the vehicle can be effectively and appropriately restrained compared to a ceiling-mounted airbag formed of a single chamber.

[0082] Moreover, the limiting tether 40 is a structure in which the restriction is released by being disconnected, so the structure of the limiting tether 40 can be simple compared to a structure in which the restriction is released by, for example, utilizing a mechanical structure to detach one end portion (the front end portion 40F or the rear end portion 40B) of the limiting tether 40 from the front wall 36F of the second chamber 36.

[0083] In addition, the limiting tether 40 is configured to be disconnected by increasing the output of the inflator 28 which is configured to change its output based on the detection result of the front and rear position of the vehicle seat 12, so its structure can be simpler than, for example, a case where a mechanism for cutting the limiting tether 40 is separately provided.

[0084] In addition, the inflator 28 may be provided with two inflators 28 instead of two inflators to increase the output. That is, when the vehicle seat 12 is located at the front side of the predetermined position, only one inflator 28 may be operated, and when the vehicle seat 12 is located at the rear side of the predetermined position or more, the second inflator 28 may be operated after the first inflator 28 is operated.

[0085] <Third Embodiment>

[0086] The third embodiment will now be described. The same reference numerals are used for the same parts as those of the first and second embodiments, and detailed descriptions thereof (including common functions) are appropriately omitted.

[0087] As shown in Fig. 8, the third embodiment is different from the first and second embodiments in that the airbag device 30 is provided for the entire left and right adjacent vehicle seats 12. Specifically, the airbag 32 is provided with a first chamber 34 and a second chamber 36 for the entire left and right adjacent vehicle seats 12.

[0088] With such a structure, since the airbag device 30 is provided for all of the left and right adjacent vehicle seats 12 , the number of components can be reduced compared to a case where the airbag device 30 is provided for each vehicle seat 12 , and thus the manufacturing cost can be reduced.

[0089] 9, one first chamber 34 may be provided for the entirety of the left and right adjacent vehicle seats 12, and a second chamber 36 may be provided for each of the left and right adjacent vehicle seats 12. That is, the second chamber 36 may be composed of a right second chamber 36R for the right vehicle seat 12R and a left second chamber 36L for the left vehicle seat 12L.

[0090] If such a structure is adopted, since the first chamber 34 is provided for the entire left and right adjacent vehicle seats 12, the number of components can be reduced (reduction in manufacturing costs), and since the second chamber 36 is provided for each of the left and right adjacent vehicle seats 12, the occupant P can be effectively and appropriately restrained according to the front and rear position of each vehicle seat 12.

[0091] The above describes the overhead airbag device 30 and the occupant restraint device 10 according to the present embodiment based on the drawings. However, the overhead airbag device 30 and the occupant restraint device 10 according to the present embodiment are not limited to the structures shown in the drawings, and the design can be appropriately changed within the scope of the present disclosure.

[0092] For example, the pulling member is not limited to the planar tether 38 as long as it can prevent the neck of the occupant P from being hooked. In addition, in the second embodiment, the following structure may be adopted: the communication hole 35 is provided at the substantially central part in the vertical direction and the substantially central part in the horizontal direction of the second chamber 36, the width of the restriction tether 40 is made smaller than the width of the restriction tether 40 described above, and the restriction tether 40 is provided in a pair on the left and right sides of the communication hole 35.

[0093] In addition, the restriction tether 40 is not limited to a structure in which the restriction is released by breaking, and for example, although the structure becomes complicated, the restriction may be released by disengaging one end (front end 40F or rear end 40B) of the restriction tether 40. In addition, the restriction tether 40 is not limited to a structure in which the restriction is released by increasing the output of the inflator 28, and may be a structure in which the restriction is released by other methods.

Claims

1. A roof-mounted airbag device, comprising: An airbag mounted on an upper side of a ceiling of a vehicle compartment, comprising a first chamber and a second chamber, wherein, in a frontal collision of the vehicle, the first chamber is supplied with gas from an inflator to cause the ceiling to rupture and expand toward the vehicle front side of an occupant seated on a vehicle seat, and the second chamber is supplied with the gas from the first chamber to expand toward the occupant; and A pulling component connects the first chamber and a support portion provided on the upper side of the ceiling, and causes the ceiling to be cracked and expanded as the first chamber expands and expands. When the occupant who is about to move toward the front side of the vehicle due to inertia is restrained by the second chamber, the pulling component relatively pulls the first chamber toward the rear side and the upper side of the vehicle.

2. The overhead airbag device according to claim 1, wherein: The pulling member is formed of a planar tether covering at least an upper half of the second chamber after expansion and deployment in a side view.

3. The overhead airbag device according to claim 1, wherein: The second chamber is provided to reach the lower side of the vehicle than the center portion in the vehicle vertical direction of the inflated and expanded first chamber and is structured to restrain at least the head and chest of the occupant.

4. The overhead airbag device according to claim 1, wherein: A limiting tether is provided inside the second chamber to limit the length of the second chamber to be deployed along the front-rear direction of the vehicle. The restriction tether is configured such that restriction by the restriction tether is released when the vehicle seat is located at or above a predetermined position on the rear side of the vehicle.

5. The overhead airbag device according to claim 4, wherein: The restraining tether is structured so as to be released from restraint by being cut.

6. The overhead airbag device according to claim 5, wherein: The inflator is configured to be capable of changing the output of the inflator based on a detection result of the front-rear position of the vehicle seat. The restraining tether is configured to be disconnected by an increase in output of the inflator.

7. An occupant restraint device, comprising: a ceiling-mounted airbag device according to any one of claims 1 to 6 provided for each vehicle seat.

8. An occupant restraint device, comprising a ceiling-mounted airbag device according to any one of claims 1 to 6 provided for the entirety of left and right adjacent vehicle seats.

9. The occupant restraint device according to claim 8, The first chamber is provided for the entirety of the left and right adjacent vehicle seats. The second chamber is provided for each of the left and right adjacent vehicle seats.

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