Floor-mounted lower limb restraint airbag device

Abstract

To provide a floor-mounted lower limb restraint airbag device which, even if there is a wide space in front of knee parts of an occupant seated in a vehicle seat, can effectively restrain the knee parts of the occupant.SOLUTION: A floor-mounted lower limb restraint airbag device 30 includes: an airbag 32 which is mounted on a vehicle lower side of a floor 20 of a cabin, and which, when gas is supplied from an inflator 28 upon a head-on collision of a vehicle, thereby ruptures the floor 20 and is expanded and deployed toward at least knee parts of an occupant P seated in a vehicle seat 12; and a tension member 38 which couples an upper part 32Uf of the airbag 32 to a support part 22 provided on the vehicle lower side of the floor 20, which ruptures the floor 20 and is deployed with expansion and deployment of the airbag 32, and which relatively pulls the upper part 32Uf of the airbag 32 toward a vehicle rear side and the vehicle lower side when the airbag 32 restrains at least the knee parts of the occupant P about to move toward a vehicle front side due to inertia force.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a floor-mounted lower leg restraint airbag device. [Background technology]

[0002] Passenger protection devices having right and left knee airbags that deploy from both the left and right sides of an occupant seated in a vehicle seat toward the knees of the occupant and press against the left and right knees, respectively, have been known for some time (see, for example, Patent Document 1). The right knee airbag has a right knee front contact surface that contacts the front side of the occupant's right knee in the deployed state, and the left knee airbag has a left knee front contact surface that contacts the front side of the occupant's left knee in the deployed state. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-161963 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the passenger protection device with the above configuration, the pair of left and right knee airbags are simply deployed toward the center of the seat width direction, and there is no reaction surface for each knee airbag. Therefore, when there is a large space in front of the knees of the passenger sitting in the vehicle seat, for example, when the front seat is moved far backward, the knees (lower legs) of the passenger, which tend to move forward due to inertial force, cannot be appropriately restrained by the pair of left and right knee airbags in the event of a frontal collision.

[0005] In addition, in the event of a frontal collision of the vehicle, for example, a restraining object that serves as a reaction surface of each knee airbag may be protruded from the floor, but since the vehicle seat can be moved forward and backward, depending on the forward and backward position of the vehicle seat, sufficient restraining force may not be obtained for the knees of the occupant. Thus, there is room for improvement in a lower leg restraint airbag device in cases where a large space exists in front of the knees of an occupant seated in a vehicle seat (where no reaction surface exists).

[0006] Therefore, an object of the present invention is to provide a floor-mounted lower leg restraint airbag device that can effectively restrain the knees of an occupant seated in a vehicle seat even when there is a large space to the front of the vehicle from the knees of the occupant. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, a floor-mounted lower leg restraint airbag device of a first aspect of the present invention comprises an airbag that is mounted on the vehicle underside of the floor of a vehicle compartment, and that, in the event of a frontal collision of the vehicle, when gas is supplied from an inflator, tears open the floor and inflates and deploys toward at least the knees of an occupant seated in the vehicle seat, and a tensioning member that connects an upper part of the airbag to a support portion provided on the vehicle underside of the floor, and that tears open the floor and deploys as the airbag inflates and deploys, and that pulls the upper part of the airbag relatively toward the rear of the vehicle and toward the vehicle underside when the airbag restrains at least the knees of the occupant who are attempting to move toward the front of the vehicle due to inertial force.

[0008] According to the first aspect of the invention, when a vehicle crashes frontally, the airbag is supplied with gas from the inflator, and inflates and deploys toward at least the knees of an occupant seated in a vehicle seat by tearing open the floor of the vehicle compartment. As the airbag inflates and deploys, a tension member connecting an upper portion of the inflated and deployed airbag to a support portion provided on the vehicle lower side of the floor tears open the floor and deploys, and when the airbag restrains at least the knees of the occupant who is moving toward the vehicle front side due to inertial force, the tension member relatively pulls the upper portion of the airbag toward the vehicle rear side and toward the vehicle lower side.

[0009] Therefore, the load from the knees of the occupant, which moves toward the front of the vehicle due to inertial force, is effectively received by the airbag, which is pulled relatively toward the rear and lower side of the vehicle by the tension member. In other words, even if the airbag is pressed toward the front of the vehicle by the knees of the occupant when the occupant is restrained, the knees of the occupant are effectively restrained by the compressive deformation of the airbag, since a reaction force is obtained by the tension member. Thus, according to the present invention, even if there is a large space (no reaction force surface) on the vehicle front side of the knees of the occupant seated in the vehicle seat, the knees of the occupant are effectively restrained. Note that "at the time of a frontal collision" as used herein also includes a case where the inevitability of a frontal collision is predicted (foreseen).

[0010] In addition, a floor-mounted lower leg restraint airbag device of a second embodiment is a floor-mounted lower leg restraint airbag device of the first embodiment, wherein the airbag and the tensioning member are configured to deploy by breaking a rupture portion formed in the floor for opening.

[0011] According to the second aspect of the invention, the airbag and the tensioning member are deployed by breaking the breakable portion formed in the floor, and therefore the airbag and the tensioning member are deployed more smoothly than when the breakable portion is not formed in the floor.

[0012] In addition, a floor-mounted lower leg restraint airbag device of a third aspect is a floor-mounted lower leg restraint airbag device of the first or second aspect, wherein the tensioning member is composed of a surface tether that covers at least the upper half of the front wall of the inflated and deployed airbag from the front side of the vehicle.

[0013] According to the third aspect of the invention, the tension member is a surface tether that covers at least the upper half of the front wall of the inflated and deployed airbag from the vehicle front side. Therefore, compared with a case in which the tension member is, for example, a pair of elongated strip tethers, the airbag is held over a wider area and pulled relatively toward the vehicle rear and downward. This allows the airbag to more effectively receive the load from the knees of the occupant who moves toward the vehicle front side due to inertial force. In addition, the surface tether has a simple structure of a single sheet, so its manufacturing cost is reduced.

[0014] In addition, a floor-mounted lower leg restraint airbag device of a fourth aspect is a floor-mounted lower leg restraint airbag device of the first or second aspect, wherein the tensile member is composed of a pair of left and right belt tethers having one end attached to the upper portion of the airbag and the other end attached to the support portion.

[0015] According to the fourth aspect of the invention, the tension member is formed of a pair of left and right band tethers, one end of which is attached to the upper part of the airbag and the other end of which is attached to the support part. Therefore, compared to a case in which the tension member is formed of, for example, a wide surface tether, the tension member can be made smaller, and the manufacturing cost can be reduced accordingly.

[0016] In addition, a floor-mounted lower leg restraint airbag device of a fifth aspect is a floor-mounted lower leg restraint airbag device of any one of the first to fourth aspects, in which the inflator is provided singly so as to supply the gas to the left-right central portion of the airbag.

[0017] According to the fifth aspect of the invention, a single inflator is provided to supply gas to the left-right central portion of the airbag, which makes the shape of the airbag simpler than when a pair of inflators are provided, for example, on the left and right.

[0018] In addition, a floor-mounted lower leg restraint airbag device of a sixth aspect is a floor-mounted lower leg restraint airbag device of any one of the first to fourth aspects, in which the inflators are provided in a pair on the left and right sides so as to supply the gas to both left and right ends of the airbag, respectively.

[0019] According to the sixth aspect of the invention, a pair of inflators are provided on the left and right sides so as to supply gas to both left and right ends of the airbag, respectively. Therefore, the airbag completes inflation and deployment earlier than when, for example, a single inflator is provided.

[0020] In addition, a floor-mounted lower leg restraint airbag device of a seventh aspect is a floor-mounted lower leg restraint airbag device of any one of the first to sixth aspects, wherein the support portion is provided with a pretensioner mechanism that pulls the pulling member when activated, and when the vehicle seat is positioned further rearward than a predetermined position, the pretensioner mechanism is activated in conjunction with the deployment of the airbag and the pulling member.

[0021] According to the seventh aspect of the invention, the support portion is provided with a pretensioner mechanism that pulls the tensioning member by being activated, and when the vehicle seat is positioned further rearward than a predetermined position, the pretensioner mechanism is activated in conjunction with the deployment of the airbag and the tensioning member. Therefore, even if the vehicle seat is positioned further rearward than a predetermined position, the inflated and deployed airbag can be brought closer to the knees of the occupant, and the knees of the occupant are effectively restrained.

[0022] In addition, a floor-mounted lower leg restraint airbag device of an eighth aspect is a floor-mounted lower leg restraint airbag device of any one of the first to seventh aspects, wherein the airbag has a first chamber that is inflated and deployed toward the rear and upper side of the vehicle as the gas is supplied from the inflator, and a second chamber that is inflated and deployed toward at least the knees of the occupant as the gas is supplied from the first chamber, and the tension member connects an upper portion of the first chamber to the support portion.

[0023] According to an eighth aspect of the invention, the airbag has a first chamber that is inflated and deployed toward the rear and upper side of the vehicle by gas supplied from an inflator, and a second chamber that is inflated and deployed toward at least the knees of an occupant by gas supplied from the first chamber, and a tension member connects an upper portion of the first chamber to the support portion.

[0024] Therefore, the load from the knees of the occupant, which moves toward the front of the vehicle due to inertial force, is effectively received by the second chamber, which is pulled relatively toward the rear and lower side of the vehicle via the first chamber by the tension member. In other words, even if the second chamber is pressed toward the front of the vehicle by the knees of the occupant when the occupant is restrained, a reaction force is obtained from the first chamber, which is pulled by the tension member, and the knees of the occupant are effectively restrained by the compressive deformation of the second chamber.

[0025] In addition, a ninth aspect of the floor-mounted lower leg restraint airbag device is a floor-mounted lower leg restraint airbag device of the eighth aspect, wherein the second chamber inflates and deploys from an upper portion of the rear wall of the first chamber, restraining at least the knees of the occupant.

[0026] According to the ninth aspect of the invention, the second chamber inflates and deploys from the upper part of the rear wall of the first chamber, restraining at least the knees of the occupant. Therefore, compared to a single airbag (not having a first chamber and a second chamber), an increase in the volume of the airbag is suppressed. In other words, an increase in the output of the inflator is suppressed, and the manufacturing cost is reduced accordingly. Effect of the Invention

[0027] As described above, according to the present invention, the knees of an occupant seated in a vehicle seat can be effectively restrained even when there is a large space to the front of the vehicle from the knees of the occupant. [Brief description of the drawings]

[0028] [Figure 1] 1A is a schematic plan view showing a floor on which the floor-mounted lower-leg restraint airbag device according to the first embodiment is mounted, and FIG. 1B is a schematic plan view showing a state in which the airbag door and the tether door of the floor on which the floor-mounted lower-leg restraint airbag device according to the first embodiment is mounted are open. [Diagram 2] 1A is a schematic plan view showing an initial deployment state of an airbag in a floor-mounted lower-leg restraint airbag device according to the first embodiment, and FIG. 1B is a schematic plan view showing a later deployment state of an airbag in a floor-mounted lower-leg restraint airbag device according to the first embodiment. [Diagram 3] 1A is a schematic side view showing an early deployment state of an airbag in a floor-mounted lower-leg restraint airbag device according to the first embodiment, and FIG. 1B is a schematic side view showing a later deployment state of an airbag in a floor-mounted lower-leg restraint airbag device according to the first embodiment. [Figure 4] 13A and 13B are schematic plan views showing an initial deployment state of an airbag in a floor-mounted lower-leg restraint airbag device according to a second embodiment, respectively. [Diagram 5]1A is a schematic side view showing an early deployment state of an airbag in a floor-mounted lower-leg restraint airbag device according to a second embodiment, and FIG. 1B is a schematic side view showing a later deployment state of an airbag in a floor-mounted lower-leg restraint airbag device according to a second embodiment. [Figure 6] 13A and 13B are schematic plan views showing an initial deployment state of an airbag in a floor-mounted lower-leg restraint airbag device according to a third embodiment, respectively. [Figure 7] 13A and 13B are schematic side views showing an early deployment state of an airbag in a floor-mounted lower-leg restraint airbag device according to a third embodiment, respectively. [Figure 8] 13A and 13B are schematic plan views showing an initial deployment state of an airbag in a floor-mounted lower-leg restraint airbag device according to a fourth embodiment, respectively. [Figure 9] 13A and 13B are schematic side views showing an early deployment state of an airbag in a floor-mounted lower-leg restraint airbag device according to a fourth embodiment, respectively. [Figure 10] 13A and 13B are schematic side views showing an early deployment state of an airbag in a floor-mounted lower-leg restraint airbag device according to a fifth embodiment, respectively. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. For convenience of explanation, the arrow UP shown in each drawing indicates the upward direction of the vehicle and the vehicle seat, the arrow FR indicates the forward direction of the vehicle and the vehicle seat, and the arrow RH indicates the rightward direction of the vehicle and the vehicle seat. Therefore, in the following description, when the directions of up / down, front / rear, and left / right are described without special mention, they refer to up / down, front / rear, and 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.

[0030] First Embodiment First, a first embodiment will be described. As shown in Fig. 1 to Fig. 3, an occupant restraint device 10 is composed of a vehicle seat 12 and a floor-mounted lower leg restraint airbag device 30 (hereinafter, may be simply referred to as "lower leg restraint airbag device 30") provided for each vehicle seat 12. Note that the "lower leg" here refers to the lower side of the knees of the occupant P, and includes at least the knees and shins.

[0031] The vehicle seat 12 is a passenger-side front seat or a rear seat of a vehicle such as an autonomous vehicle in which the front side of the seat is wide in the front-rear direction. The vehicle seat 12 has a seat cushion 14 on which an occupant sits (supporting the occupant's buttocks and thighs), a seat back 16 that is provided on the rear side of the seat cushion 14 so as to be rotatable about the seat width direction as an axial direction and supports the occupant's back, and a headrest 18 that is provided on the upper end of the seat back 16 so as to be able to rise and fall and support the occupant's head.

[0032] In each figure, a crash test dummy (human dummy) is shown seated on the seat cushion 14 of the vehicle seat 12 as a model of the occupant (seater) to be protected. The dummy is, for example, a frontal crash test dummy (Hybrid III) AM50 (50th percentile of American adult males). The dummy is seated in a standard seating position defined by the crash test method, and the vehicle seat 12 is located at a reference setting position corresponding to the seating position. Hereinafter, the dummy will be referred to as "occupant P."

[0033] As shown in each drawing, an occupant P seated 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 24. The seat belt device 24 is a three-point seat belt device.

[0034] A lower leg restraint airbag device 30 is mounted on the lower side of the vehicle compartment floor (floor panel) 20 in front of the vehicle seat 12. The lower leg restraint airbag device 30 includes an airbag 32, an inflator 28, and a module case (not shown). The airbag 32 is normally stored in a folded state together with the inflator 28 in the module case. The module case is formed in a hollow, generally rectangular parallelepiped shape, and is installed on the lower side of the vehicle compartment floor 20.

[0035] The vehicle is equipped with a control device (ECU) that controls 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, and is configured to be able to detect a frontal collision of the vehicle or predict (foresee) the inevitability of a frontal collision. The control device is configured to activate the inflator 28 when it detects or predicts a frontal collision of the vehicle (hereinafter referred to as "at the time of a frontal collision") based on information from the collision sensor.

[0036] The inflator 28 is, for example, a combustion-type or cold gas-type, substantially cylindrical inflator, and is disposed with its axis aligned along the front-rear direction. The inflator 28 is activated by a control device at the time of a frontal collision of the vehicle to generate gas. Note that the type of frontal collision of the vehicle in which the control device activates the inflator 28 includes, in addition to a full-wrap frontal collision, an offset frontal collision such as an oblique collision or a minute-wrap collision.

[0037] The airbag 32 is configured to inflate and deploy (deploy and inflate) by the inflation pressure caused by gas supplied from the inflator 28, splitting the floor 20 and directing it toward the left and right knees and shins (at least the left and right knees) of the occupant P seated in the vehicle seat 12, and is formed in an approximately inverted "L" shape when viewed from the side in the vehicle width direction.

[0038] The floor 20 has a tear line 20A formed in the left-right direction as a breaking portion for ripping open, and the airbag 32 inflates and deploys by breaking the tear line 20A. The portion that breaks from the tear line 20A and turns forward forms the airbag door 26.

[0039] The inflated and deployed airbag 32 is formed to a size sufficient to cover the left and right knees and shins of the occupant P from the front side (specifically, from the diagonally upper front side). In other words, the inflated and deployed airbag 32 is formed to a width, height, and thickness sufficient to restrain at least the left and right knees of the occupant P that tend to move forward due to inertial force in the event of a frontal collision of the vehicle, and is compressively deformable by being pressed against at least the left and right knees of the occupant P (see Figs. 2(B) and 3(B)).

[0040] The airbag 32 is formed into a bag shape by overlapping two pieces of base fabric and sewing the peripheral portions. The base fabric is made of, for example, a polyamide or polyester fabric material. The inflator 28 is provided singly so as to supply gas to the center in the left-right direction of the lower end portion 32D of the airbag 32. Therefore, the airbag 32 is formed into a tapered shape in which the width gradually narrows toward the lower end portion 32D in a plan view.

[0041] In addition, on the lower side of the floor 20, a pair of left and right tear lines 20B formed in the floor 20 along the fore-and-aft direction are split and deployed upward as the airbag 32 inflates and deploys, and a surface tether 38 is provided as a tensile member that connects the upper end (upper part) 32Uf of the front wall 32F of the airbag 32 after inflation and deployment to a pair of left and right support parts 22 provided on the lower side of the floor 20 at a predetermined length or more rearward from the module case.

[0042] The surface tether 38 is configured to relatively pull the upper end 32Uf of the front wall 32F of the airbag 32 diagonally downward and rearward (rearward and downward) when at least the left and right knees of the occupant P who is moving forward due to inertial force are restrained by the airbag 32. In other words, the surface tether 38 is configured to enable the airbag 32 to receive a reaction force from the front side.

[0043] The surface tether 38 after deployment is formed to a size that can cover, from the front side, at least the upper half of the front wall 32F of the inflated and deployed airbag 32. The surface tether 38 is attached to the airbag 32 by sewing the periphery of the area where the surface tether 38 overlaps so as to cover the front wall 32F of the airbag 32 to the front wall 32F.

[0044] In order to facilitate efficient pulling of the airbag 32 diagonally downward and rearward, the surface tether 38 is formed in a generally right-angled triangle shape with a right angle at the lower front end in a side view. That is, the surface tether 38 is made of a single piece of fabric material, such as a polyamide or polyester material, and is formed in a generally obtuse isosceles triangle shape in a front view. The portion that breaks off from the tear line 20B and turns outward in the seat width direction forms the tether door 27.

[0045] 1, the tear line 20A and the pair of left and right tear lines 20B are formed continuously. In other words, the tear line 20A and each tear line 20B are formed to form a roughly "U" shape in plan view. In addition, where the tear line 20A and each tear line 20B intersect at a right angle in plan view, a tear line 20C of a predetermined length is formed diagonally forward and outward. This configuration allows the airbag door 26 and the tether door 27 to be easily rolled up.

[0046] Next, the operation of the lower leg restraint airbag device 30 according to the first embodiment configured as above will be described.

[0047] In the event of a frontal collision of the vehicle, the inflator 28 is activated by 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 airbag 32. Then, the tear line 20A formed on the floor 20 of the passenger compartment is ruptured by the inflation pressure of the airbag 32, and the airbag 32 is inflated and deployed toward the left and right knees and shins of the occupant P seated in the vehicle seat 12.

[0048] As the airbag 32 inflates and deploys, the surface tether 38 that connects the upper end 32Uf of the front wall 32F of the airbag 32 after inflation and deployment to the pair of left and right support parts 22 provided on the lower side of the floor 20 tears open the tear line 20B formed on the floor 20 and deploys. When the airbag 32 restrains at least the left and right knees of the occupant P who is trying to move forward due to inertial force, the surface tether 38 relatively pulls the upper end 32Uf of the front wall 32F of the airbag 32 diagonally downward and rearward. In other words, the surface tether 38 forms a reaction surface against the airbag 32.

[0049] Therefore, the load from at least the left and right knees of the occupant P who moves forward due to inertial force can be effectively received by the airbag 32 which is pulled relatively diagonally downward and rearward by the surface tethers 38. In other words, even if the airbag 32 is pressed forward by the left and right knees of the occupant P when the occupant is restrained, a reaction force is obtained by the surface tethers 38, so that the airbag 32 is compressed and deformed, and at least the left and right knees of the occupant P can be effectively restrained.

[0050] Thus, according to the first embodiment, even if there is a wide space in front of the left and right knees and shins of an occupant P seated in the vehicle seat 12 (there is no reaction surface such as an instrument panel), at least the left and right knees of the occupant P can be effectively restrained (in particular, sufficient restraining force can be secured at the beginning of the collision).

[0051] Moreover, since the surface tether 38 covers at least the upper half of the front wall 32F of the inflated and deployed airbag 32 from the front side, the airbag 32 is pulled relatively diagonally downward and rearward while being held over a wider area than in a configuration in which the airbag 32 is pulled relatively diagonally downward and rearward by, for example, a pair of left and right elongated tethers. This allows the airbag 32 to more effectively receive the load from at least the left and right knees of the occupant P who moves forward due to inertial force.

[0052] As a result, even if an occupant P seated in the vehicle seat 12 is not wearing a seat belt, or even if the occupant P is wearing a seat belt but is in a comfortable position with the seat back 16 tilted far back and is not sufficiently restrained by the lap belt of the seat belt, it is possible to effectively restrain at least the left and right knees of the occupant P. In addition, since the surface tether 38 has a simple configuration of a single sheet, the manufacturing cost can be reduced.

[0053] As described above, the airbag 32 and the surface tether 38 deploy by breaking the tear lines 20A and 20B formed in the floor 20. Therefore, the airbag 32 and the surface tether 38 can deploy more smoothly than if the tear lines 20A and 20B were not formed in the floor 20.

[0054] Also, a single inflator 28 is provided to supply gas to the left-right central portion of the lower end portion 32D of the airbag 32. Therefore, compared to a case in which a pair of inflators 28 are provided, for example, on the left and right, the shape of the airbag 32 can be made simpler (the lower end portion 32D does not need to be formed in a bifurcated shape branched into the left and right, as in the airbag 32 according to the second embodiment described later).

[0055] <Second embodiment> Next, a second embodiment will be described. Note that the same reference numerals are used for the same parts as those in the first embodiment, and detailed descriptions (including common functions) will be omitted as appropriate.

[0056] As shown in Figures 4 and 5, this second embodiment differs from the first embodiment only in that a pair of left and right inflators 28 are provided to supply gas to both left and right ends of the lower end 32D of the airbag 32, and that the tensile member is composed of a pair of left and right belt tethers 40, one end of which is attached to each of the upper ends (upper parts) 32Us of both left and right side walls 32S of the airbag 32 and the other end of which is attached to each of a pair of left and right support parts 22.

[0057] Specifically, two inflators 28 are provided, a left inflator 28L and a right inflator 28R. Therefore, a lower end portion 32D of the airbag 32 is formed in a bifurcated shape in a plan view. That is, the inflators 28L and 28R are connected to the left and right lower end portions 32D of the airbag 32, which are bifurcated, respectively.

[0058] According to the second embodiment configured as described above, the inflators 28 are provided in a pair on the left and right sides so as to supply gas to both left and right ends of the airbag 32, i.e., the inflators 28L, 28R are connected to the left and right lower ends 32D of the airbag 32, which are branched into two parts, respectively. As a result, the airbag 32 can complete inflation and deployment sooner than when a single inflator 28 is provided.

[0059] The tension member is composed of a pair of left and right band tethers 40. That is, one end of each band tether 40 is attached to the upper end portions 32Us of the left and right side walls 32S of the airbag 32, respectively, and the other end of each band tether 40 is attached to the pair of left and right support portions 22, respectively. Therefore, compared to a case in which the tension member is composed of, for example, a wide surface tether 38, the tension member can be made smaller, and the manufacturing cost can be reduced accordingly.

[0060] <Third embodiment> Next, a third embodiment will be described. Note that the same reference numerals are used for the same parts as those in the first and second embodiments, and detailed descriptions (including common functions) will be omitted as appropriate.

[0061] As shown in Figures 6 and 7, in the third embodiment, the airbag 32 has a first chamber 34 that is inflated and deployed diagonally toward the upper rear (rear and upward) when gas is supplied from the inflator 28, and a second chamber 36 that is inflated and deployed from an upper part of the first chamber 34 diagonally toward the lower rear (rear and downward), i.e., toward the left and right knees and shins (at least the left and right knees) of the occupant P, which are different from the first embodiment only in that the belt tether 40 connects upper ends (upper parts) 34U of the left and right side walls 34S of the first chamber 34 to the pair of left and right support parts 22.

[0062] The second chamber 36 is provided on an upper portion of the rear wall 34B of the first chamber 34 via a communication hole 35, and gas is supplied from the first chamber 34 through the communication hole 35. In other words, the second chamber 36 is configured to inflate and deploy toward the left and right knees and shins of the occupant P with a predetermined timing delay from the first chamber 34. After inflating and deploying, the second chamber 36 is disposed in front of the left and right knees and shins of the occupant P.

[0063] The communication hole 35 is provided at approximately the center in the vertical direction and the center in the horizontal direction of the second chamber 36. After being inflated and deployed, the second chamber 36 is formed to have a size large enough to cover at least the left and right knees of the occupant P from the front side (more specifically, the diagonally upper front side).

[0064] In other words, the second chamber 36 after inflation and deployment is formed with a width, height, and thickness capable of restraining at least the left and right knees of the occupant P that tend to move forward due to inertial force during a frontal collision of the vehicle, and is capable of being compressed and deformed by being pressed against at least the left and right knees of the occupant P.

[0065] The first chamber 34 and the second chamber 36 are each formed into a bag shape by overlapping two pieces of base fabric and sewing their peripheral parts. The base fabric is made of, for example, a polyamide or polyester fabric material. The front wall 36F of the second chamber 36 is attached to the rear wall 34B of the first chamber 34 by sewing the periphery of the communication hole 35, which is formed in a circular shape, to each other.

[0066] According to the third embodiment having such a configuration, the load from at least the left and right knees of the occupant P who moves forward due to inertial force can be effectively received by the second chamber 36 which is pulled relatively diagonally downward and rearward via the first chamber 34 by the belt tether 40. In other words, even if the second chamber 36 is pressed forward by the left and right knees of the occupant P when the occupant is restrained, a reaction force is obtained by the first chamber 34 which is pulled by the belt tether 40, so that the second chamber 36 is compressed and deformed, and at least the left and right knees of the occupant P can be effectively restrained.

[0067] In particular, the second chamber 36 inflates and deploys from an upper portion of the rear wall 34B of the first chamber 34, restraining at least the left and right knees of the occupant P. Therefore, an increase in the volume of the airbag 32 can be suppressed compared to a case in which the airbag 32 is configured as a single body (not including the first chamber 34 and the second chamber 36). In other words, an increase in the output of the inflator 28 can be suppressed, and the manufacturing cost can be reduced accordingly.

[0068] <Fourth embodiment> Next, a fourth embodiment will be described. Note that the same reference numerals are used for the same parts as those in the first to third embodiments, and detailed descriptions (including common functions) will be omitted as appropriate.

[0069] As shown in Figures 8 and 9, in the fourth embodiment, similar to the second embodiment, the only difference from the third embodiment is that a pair of inflators 28 are provided on the left and right sides so as to supply gas to both left and right ends of the lower end 34D of the first chamber 34, respectively.

[0070] That is, two inflators 28 are provided, a left inflator 28L and a right inflator 28R, as in the second embodiment. Therefore, the lower end 34D of the first chamber 34 is formed in a bifurcated shape in a plan view. That is, the inflators 28L and 28R are connected to the left and right lower end 34D of the first chamber 34, which are bifurcated, respectively.

[0071] According to the fourth embodiment having such a configuration, it is possible to obtain the same effect as the third embodiment described above, and similarly to the second embodiment described above, it is possible to complete inflation and deployment of the first chamber 34 of the airbag 32 earlier than when, for example, a single inflator 28 is provided, and it is also possible to complete inflation and deployment of the second chamber 36 of the airbag 32 earlier.

[0072] <Fifth embodiment> Finally, a fifth embodiment will be described below. Note that the same reference numerals are used for the same parts as those in the first to fourth embodiments, and detailed descriptions (including common functions) will be omitted as appropriate.

[0073] As shown in FIG. 10, in the fifth embodiment, a pretensioner mechanism 42 that is activated to pull the surface tether 38 is provided on each of a pair of left and right support portions 22, and the only difference from the first embodiment described above is that when the vehicle seat 12 is positioned rearward beyond a predetermined position, each pretensioner mechanism 42 is activated in conjunction with the deployment of the airbag 32 and the surface tether 38.

[0074] The pretensioner mechanism 42 is a known mechanism, and includes, for example, a gas generator (not shown) and a moving mechanism (not shown) that instantaneously moves diagonally downward and rearward when the gas generator is activated. The moving mechanism may be, for example, a mechanism including a rack and pinion. The support portion 22 to which the lower end of the surface tether 38 is attached is mechanically connected to the moving mechanism.

[0075] Therefore, if each gas generator is configured to operate at the same time that the inflated airbag 32 restrains at least the left and right knees of the occupant P, the operation of each gas generator causes each moving mechanism to instantly move diagonally downward and rearward, and the surface tether 38 can be instantly retracted diagonally downward and rearward via each support portion 22.

[0076] According to the fifth embodiment having such a configuration, as shown in the figure, even if the vehicle seat 12 is positioned further rearward than a predetermined position (for example, the position shown in Figures 2 to 9), the inflated and deployed airbag 32 can be brought closer to at least the left and right knees of the occupant P than in the first to fourth embodiments, and at least the left and right knees of the occupant P can be effectively restrained.

[0077] The above describes the floor-mounted lower leg restraint airbag device 30 according to this embodiment based on the drawings. However, the floor-mounted lower leg restraint airbag device 30 according to this embodiment is not limited to the one shown in the drawings, and the design can be modified as appropriate within the scope that does not deviate from the gist of the present invention.

[0078] For example, instead of tear lines 20A and 20B, floor 20 may be provided in advance with rotatable airbag door 26 and tether door 27. Also, floor 20 may be a floor carpet instead of a floor panel. In this case, the module case may be installed above the floor panel (between the floor panel and the floor carpet), and tear lines are formed in the floor carpet.

[0079] The tension member in the second to fourth embodiments may be a surface tether 38 rather than the band tether 40. The tension member in the first and fifth embodiments may be a band tether 40 rather than the band tether 38. A pretensioner mechanism 42 may be provided on each of the pair of left and right support portions 22 in the second to fourth embodiments. In the fifth embodiment, the pair of left and right support portions 22 may be configured to be instantly pulled diagonally downward and rearward by a single pretensioner mechanism 42. [Explanation of symbols]

[0080] 12 Vehicle seats 20th Floor 20A Tear line (break) 20B Tear line (break) 22 Support part 28 Inflator 30 Floor-mounted lower leg restraint airbag device 32 Airbag 34 First Chamber 36 Second Chamber 38 Surface tether (tensile member) 40 Belt tether (tensile member) 42 Pretensioner mechanism P Crew

Claims

1. an airbag that is mounted on a vehicle lower side of a floor of a vehicle compartment and that, in the event of a frontal collision of the vehicle, is supplied with gas from an inflator, tears open the floor and inflates and deploys toward at least the knees of an occupant seated in a vehicle seat; a tension member that connects an upper portion of the airbag and a support portion provided on the vehicle lower side of the floor, and that tears and deploys the floor as the airbag inflates and deploys, and that pulls the upper portion of the airbag relatively toward the rear side of the vehicle and toward the vehicle lower side when at least the knees of the occupant who is moving toward the vehicle front side due to inertial force are restrained by the airbag; A floor-mounted lower leg restraint airbag device.

2. 2. A floor-mounted lower leg restraint airbag device according to claim 1, wherein the airbag and the tension member are configured to be deployed by breaking a breaking portion for opening formed in the floor.

3. 3. A floor-mounted lower leg restraint airbag device according to claim 1, wherein the tension member is formed of a surface tether that covers at least an upper half of a front wall of the inflated and deployed airbag from the front side of the vehicle.

4. 3. A floor-mounted lower leg restraint airbag device as described in claim 1 or claim 2, wherein the tension member is composed of a pair of left and right belt tethers having one end attached to the upper portion of the airbag and the other end attached to the support portion.

5. 3. A floor-mounted lower leg restraint airbag device according to claim 1, wherein the inflator is provided singly so as to supply the gas to a central portion of the airbag in the left-right direction.

6. 3. A floor-mounted lower leg restraint airbag device according to claim 1, wherein the inflators are provided in a pair on the left and right sides so as to supply the gas to both left and right ends of the airbag, respectively.

7. The support portion is provided with a pretensioner mechanism that tensions the tension member by being activated, 3. A floor-mounted lower leg restraint airbag device as described in claim 1 or 2, wherein the pretensioner mechanism is activated in conjunction with the deployment of the airbag and the tensioning member when the vehicle seat is positioned further rearward of the vehicle than a predetermined position.

8. The airbag comprises: a first chamber that is inflated and deployed toward a rear side and an upper side of the vehicle by receiving the gas from the inflator; a second chamber that is inflated and deployed toward at least the knees of the occupant by receiving the gas from the first chamber; having 3. The floor-mounted lower leg restraint airbag device according to claim 1, wherein the tension member connects an upper portion of the first chamber and the support portion.

9. 9. The floor-mounted lower leg restraint airbag device according to claim 8, wherein the second chamber inflates and deploys from an upper portion of a rear wall of the first chamber to restrain at least the knees of the occupant.

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