Floor-mounted lower limb restraint airbag system

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 limb restraint airbag device.

Background Art

[0002] An occupant protection device having a right knee airbag and a left knee airbag that deploy from both the left and right sides of an occupant sitting on a vehicle seat toward the occupant's knees and press the left and right knees respectively is conventionally known (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

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the occupant protection device having the above configuration, by simply deploying the pair of left and right knee airbags toward the center in the seat width direction, there is no reaction surface for each knee airbag. Therefore, for example, when there is a large space in front of the knees of an occupant sitting on a vehicle seat, such as a front seat moved significantly rearward, at the time of a frontal collision of the vehicle, the knees (lower limbs) of the occupant who tries to move forward due to inertia cannot be appropriately restrained by the pair of left and right knee airbags.

[0005] Furthermore, in the event of a frontal collision, a configuration could be considered in which restraints protrude from the floor, for example, to serve as the reaction force surfaces for each knee airbag. However, since the fore-aft position of a vehicle seat can be changed, depending on the fore-aft position of the vehicle seat, sufficient restraint force may not be obtained for the occupant's knees. Thus, there is room for improvement in lower limb restraint airbag systems when there is a large space in front of the knees of an occupant seated in a vehicle seat (i.e., no reaction force surface exists).

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

[0007] To achieve the above objectives, a floor-mounted lower limb restraint airbag device according to a first embodiment of the present invention includes an airbag mounted on the lower side of the vehicle floor of the passenger compartment, which, in the event of a frontal collision of the vehicle, is supplied with gas from an inflator, causing the floor to split open and inflating and deploying toward at least the knees of an occupant seated in a vehicle seat; and a tension member that connects the upper part of the airbag to a support portion provided on the lower side of the vehicle floor, and which, when the floor splits open and deploys as the airbag inflates and deploys, restraining at least the knees of the occupant who is attempting to move toward the front of the vehicle due to inertial force, relatively pulls the upper part of the airbag toward the rear and downward side of the vehicle.

[0008] According to the first embodiment of the invention, in the event of a frontal collision of a vehicle, gas is supplied from an inflator, causing the airbag to inflate and deploy, rupturing the floor of the passenger compartment and moving toward at least the knees of the occupant seated in the vehicle seat. As the airbag inflates and deploys, a tension member connecting the upper part of the inflated airbag to a support part provided on the lower side of the floor of the vehicle ruptures and deploys, restraining at least the knees of the occupant who is trying to move toward the front of the vehicle due to inertial force, and relatively pulling the upper part of the airbag toward the rear and downward side of the vehicle.

[0009] Therefore, the load from the occupant's knees, which has moved forward due to inertial force, is effectively absorbed by the airbag, which is pulled relatively towards the rear and downward side of the vehicle by the tension member. In other words, even if the airbag is pressed forward by the occupant's knees when the occupant is restrained, a reaction force is obtained from the tension member, and the occupant's knees are effectively restrained by the compression deformation of the airbag. Thus, according to the present invention, even when there is a large space in front of the occupant's knees (no reaction force surface) when the occupant is seated in a vehicle seat, the occupant's knees are effectively restrained. Note that "during a frontal collision" as used here also includes when the inevitability of a frontal collision is predicted (foreseen).

[0010] Furthermore, the second embodiment of the floor-mounted lower limb restraint airbag device is the same as the first embodiment of the floor-mounted lower limb restraint airbag device, wherein the airbag and the tension member are configured to deploy by rupturing a tearing section formed in the floor.

[0011] According to the second embodiment of the invention, the airbag and tension member deploy by rupturing a tear-out section formed in the floor. Therefore, the airbag and tension member deploy more smoothly than in the case where no tear-out section is formed in the floor.

[0012] Furthermore, the third embodiment of the floor-mounted lower limb restraint airbag device is the floor-mounted lower limb restraint airbag device of the first or second embodiment, wherein the tension 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 embodiment of the invention, the tension 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 of the vehicle. Therefore, compared to the case where the tension member is composed of, for example, a pair of elongated strip tethers, the airbag is held over a wider area and pulled relatively towards the rear and downward side of the vehicle. As a result, the load from the occupant's knees, which has moved towards the front of the vehicle due to inertia, is more effectively absorbed by the airbag. In addition, since the surface tether has a simple configuration of one piece, its manufacturing cost is reduced.

[0014] Furthermore, the fourth embodiment of the floor-mounted lower limb restraint airbag device is the floor-mounted lower limb restraint airbag device of the first or second embodiment, wherein the tension member is composed of a pair of left and right 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 portion.

[0015] According to the fourth embodiment of the invention, the tension member is composed 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. Therefore, compared to the case in which the tension member is composed of, for example, a wide surface tether, the tension member can be made smaller, and the manufacturing cost is reduced accordingly.

[0016] Furthermore, the fifth embodiment of the floor-mounted lower limb restraint airbag device is a floor-mounted lower limb restraint airbag device of any one of the first to fourth embodiments, wherein the inflator is provided as a single unit to supply the gas to the left-right central part of the airbag.

[0017] According to the fifth aspect of the invention, the inflator is provided as a single unit to supply gas to the left-right central portion of the airbag. Therefore, the shape of the airbag is simpler compared to the case where, for example, a pair of inflators are provided on the left and right sides.

[0018] Furthermore, the sixth embodiment of the floor-mounted lower limb restraint airbag device is a floor-mounted lower limb restraint airbag device according to any one of the first to fourth embodiments, wherein the inflators are provided in pairs, left and right, to supply the gas to both left and right ends of the airbag, respectively.

[0019] According to the sixth aspect of the invention, the inflators are provided in pairs, one on each side, to supply gas to both ends of the airbag in the left-right direction. Therefore, the airbag inflates and deploys more quickly compared to, for example, a single inflator.

[0020] Furthermore, the seventh embodiment of the floor-mounted lower limb restraint airbag device is a floor-mounted lower limb restraint airbag device of any one of the first to sixth embodiments, wherein the support portion is provided with a pretensioner mechanism that, when activated, pulls the tension member, and the pretensioner mechanism is activated in conjunction with the deployment of the airbag and the tension member when the vehicle seat is located beyond a predetermined position towards the rear of the vehicle.

[0021] According to the seventh aspect of the invention, the support portion is provided with a pretensioner mechanism that, when activated, pulls a tension member, and the pretensioner mechanism is activated in conjunction with the deployment of the airbag and tension member when the vehicle seat is positioned further rearward than a predetermined position. Therefore, even when the vehicle seat is positioned further rearward than a predetermined position, it is possible to bring the inflated and deployed airbag closer to the occupant's knees, thereby effectively restraining the occupant's knees.

[0022] Further, the floor-mounted lower limb restraint airbag device according to the eighth aspect is the floor-mounted lower limb restraint airbag device according to any one of the first to seventh aspects, wherein the airbag includes a first chamber that expands and deploys toward the rear side and the upper side of the vehicle when gas is supplied from the inflator, and a second chamber that expands and deploys toward at least the knees of the occupant when gas is supplied from the first chamber, and the tension member connects the upper portion of the first chamber and the support portion.

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

[0024] Therefore, the load from the knees of the occupant who has moved forward to the front side of the vehicle due to inertial force is effectively received by the second chamber that is relatively pulled toward the rear side and the lower side of the vehicle through the first chamber by the tension member. That is, even when the second chamber is pressed by the knees of the occupant toward the front side of the vehicle during occupant restraint, a reaction force can be obtained from the first chamber pulled by the tension member, so that the knees of the occupant are effectively restrained by the compression deformation of the second chamber.

[0025] Further, the floor-mounted lower limb restraint airbag device according to the ninth aspect is the floor-mounted lower limb restraint airbag device according to the eighth aspect, wherein the second chamber expands and deploys from the upper portion of the rear wall of the first chamber and restrains at least the knees of the occupant.

[0026] According to the invention of the ninth aspect, the second chamber expands and deploys from the upper part of the rear wall of the first chamber and restrains at least the knees of the occupant. Therefore, compared with the case where the airbag is configured as a single unit (not having the first chamber and the second chamber), an increase in the capacity of the airbag is suppressed. That is, an increase in the output of the inflator is suppressed, and accordingly, the manufacturing cost is reduced.

Effect of the Invention

[0027] As described above, according to the present invention, even when there is a wide space on the front side of the vehicle of the knees of an occupant sitting on a vehicle seat, the knees of the occupant can be effectively restrained.

Brief Description of the Drawings

[0028] [Figure 1] (A) It is a schematic plan view showing a floor on which a floor-mounted lower limb restraint airbag device according to the first embodiment is mounted. (B) It is a schematic plan view showing a state when an airbag door and a tether door of the floor on which the floor-mounted lower limb restraint airbag device according to the first embodiment is mounted are opened. [Figure 2] (A) It is a schematic plan view showing an initial state of deployment of an airbag in a floor-mounted lower limb restraint airbag device according to the first embodiment. (B) It is a schematic plan view showing a late state of deployment of an airbag in a floor-mounted lower limb restraint airbag device according to the first embodiment. [Figure 3] (A) It is a schematic side view showing an initial state of deployment of an airbag in a floor-mounted lower limb restraint airbag device according to the first embodiment. (B) It is a schematic side view showing a late state of deployment of an airbag in a floor-mounted lower limb restraint airbag device according to the first embodiment. [Figure 4] (A) It is a schematic plan view showing an initial state of deployment of an airbag in a floor-mounted lower limb restraint airbag device according to the second embodiment. (B) It is a schematic plan view showing a late state of deployment of an airbag in a floor-mounted lower limb restraint airbag device according to the second embodiment. [Figure 5](A) A schematic side view showing the initial state of airbag deployment in the floor-mounted lower limb restraint airbag device according to the second embodiment. (B) A schematic side view showing the later state of airbag deployment in the floor-mounted lower limb restraint airbag device according to the second embodiment. [Figure 6] (A) A schematic plan view showing the initial state of airbag deployment in the floor-mounted lower limb restraint airbag device according to the third embodiment. (B) A schematic plan view showing the later state of airbag deployment in the floor-mounted lower limb restraint airbag device according to the third embodiment. [Figure 7] (A) A schematic side view showing the initial state of airbag deployment in the floor-mounted lower limb restraint airbag device according to the third embodiment. (B) A schematic side view showing the later state of airbag deployment in the floor-mounted lower limb restraint airbag device according to the third embodiment. [Figure 8] (A) A schematic plan view showing the initial state of airbag deployment in the floor-mounted lower limb restraint airbag device according to the fourth embodiment. (B) A schematic plan view showing the later state of airbag deployment in the floor-mounted lower limb restraint airbag device according to the fourth embodiment. [Figure 9] (A) A schematic side view showing the initial state of airbag deployment in the floor-mounted lower limb restraint airbag device according to the fourth embodiment. (B) A schematic side view showing the later state of airbag deployment in the floor-mounted lower limb restraint airbag device according to the fourth embodiment. [Figure 10] (A) A schematic side view showing the initial state of airbag deployment in the floor-mounted lower limb restraint airbag device according to the fifth embodiment. (B) A schematic side view showing the later state of airbag deployment in the floor-mounted lower limb restraint airbag device according to the fifth embodiment. [Modes for carrying out the invention]

[0029] The embodiments of the present invention will be described in detail below with reference to the drawings. For the sake of explanation, in each figure, the arrow UP will indicate the upward direction of the vehicle and the vehicle seat, the arrow FR will indicate the forward direction of the vehicle and the vehicle seat, and the arrow RH will indicate the rightward direction of the vehicle and the vehicle seat. Therefore, in the following description, when the directions of up and down, front and back, and left and right are mentioned without further specification, they refer to the up and down, front and back, and left and right directions of the vehicle and the vehicle seat. Also, the left and right directions are synonymous with the vehicle width direction and the seat width direction.

[0030] <First Embodiment> First, the first embodiment will be described. As shown in Figures 1 to 3, the occupant restraint device 10 consists of a vehicle seat 12 and a floor-mounted lower limb restraint airbag device 30 (hereinafter sometimes simply referred to as "lower limb restraint airbag device 30") provided for each vehicle seat 12. Here, "lower limb" refers to the part of the occupant P below the knee, and includes at least the knee and shin.

[0031] The vehicle seat 12 is a front or rear passenger seat of a vehicle such as an autonomous vehicle, which has ample space in the front of the seat in the front-to-back direction. The vehicle seat 12 includes a seat cushion 14 on which the occupant sits (supporting the occupant's buttocks and thighs), a seat back 16 that is rotatably mounted on the rear side of the seat cushion 14 in the seat width direction and supports the occupant's back, and a headrest 18 that is vertically movable at the upper end of the seat back 16 and supports the occupant's head.

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

[0033] Furthermore, as shown in each figure, the occupant P seated on the seat cushion 14 of the vehicle seat 12 is restrained to the vehicle seat 12 by the seat belt provided by the seat belt device 24. The seat belt device 24 is a three-point seat belt device.

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

[0035] The vehicle is equipped with a control unit (ECU) that controls the operation of the inflator 28. The control unit is electrically connected to the inflator 28 and collision sensors (including cameras, etc., not shown), and is configured to detect a frontal collision of the vehicle or predict (foresee) the inevitability of a frontal collision. Based on information from the collision sensors, the control unit activates 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").

[0036] The inflator 28 is, for example, a combustion-type or cold-gas-type, substantially cylindrical inflator, positioned with its axis aligned with the front-to-rear direction. This inflator 28 is activated by a control device during a frontal collision of a vehicle, generating gas. The types of frontal collisions in which the control device activates the inflator 28 include not only full-wrap frontal collisions but also offset frontal collisions such as oblique collisions and minute-wrap collisions.

[0037] The airbag 32 is designed to expand and deploy (deploy and expand) towards the left and right knees and shins (at least the left and right knees) of the occupant P seated in the vehicle seat 12 by the expansion pressure caused by the gas supplied from the inflator 28, which causes the floor 20 to split open. In a side view taken from the width direction of the vehicle, it is formed in a roughly inverted "L" shape.

[0038] Furthermore, the floor 20 has tear lines 20A formed along the left-right direction as a rupture point for opening, and the airbag 32 inflates and deploys by rupturing these tear lines 20A. The portion that ruptures from the tear lines 20A and curls forward forms the airbag door 26.

[0039] The inflated and deployed airbag 32 is formed to be large enough to cover the left and right knees and shins of the occupant P from the front (more specifically, diagonally forward and upward). In other words, the inflated and deployed airbag 32 is formed to have a width, height, and thickness that can restrain at least the left and right knees of the occupant P, which tend to move forward due to inertial force during a frontal collision of the vehicle, and is compressible and deformable when pressed against at least the left and right knees of the occupant P (see Figures 2(B) and 3(B)).

[0040] The airbag 32 is formed into a bag shape by overlapping two base fabrics and sewing their edges together. The base fabric is made of, for example, a polyamide or polyester material. The inflator 28 is a single unit that supplies gas to the center of the lower end 32D of the airbag 32 in the left-right direction. Therefore, in a plan view, the airbag 32 is formed in a tapered shape, with its width gradually narrowing towards the lower end 32D.

[0041] Furthermore, on the lower side of the floor 20, a surface tether 38 is provided as a tensioning member. As the airbag 32 inflates and deploys, it splits a pair of left and right tear lines 20B formed on the floor 20 in the front-rear direction and deploys upward, connecting the upper end (upper part) 32Uf of the front wall 32F of the inflated airbag 32 with a pair of support parts 22 provided on the lower side of the floor 20 at a predetermined length or more behind the module case.

[0042] The surface tether 38 is configured to relatively pull the upper end portion 32Uf of the front wall 32F of the airbag 32 diagonally backward and downward (rearward and downward) 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. In other words, the surface tether 38 is configured to allow the airbag 32 to receive a reaction force from the front.

[0043] Furthermore, the deployed face tether 38 is formed to be large enough to cover at least the upper half of the front wall 32F of the inflated and deployed airbag 32 from the front. The face tether 38 is attached to the airbag 32 by sewing the area around the front wall 32F that overlaps to cover the front wall 32F of the airbag 32.

[0044] Furthermore, in order to efficiently and relatively pull the airbag 32 diagonally downward and rearward, the surface tether 38 is formed in a roughly right-angled triangular shape with its lower front end forming a right angle when viewed from the side. In other words, the surface tether 38 is formed in a roughly obtuse isosceles triangular shape when viewed from the front, using a single piece of fabric, such as polyamide or polyester. The portion that breaks from the tear line 20B and curls outward in the seat width direction forms the tether door 27.

[0045] Furthermore, as shown in Figure 1, the tear line 20A and the pair of left and right tear lines 20B are formed in a continuous manner. In other words, the tear line 20A and each tear line 20B are formed to form a roughly "U" shape in plan view. Also, in plan view, at the point where the tear line 20A and each tear line 20B intersect at a right angle, a tear line 20C of a predetermined length is formed diagonally forward and outward. This configuration makes the airbag door 26 and tether door 27 easier to roll up.

[0046] The operation of the lower limb restraint airbag device 30 according to the first embodiment, which has the configuration described above, will now be explained.

[0047] During a frontal collision, the inflator 28 is activated by the control device, and gas is ejected from the inflator 28. The gas ejected from the inflator 28 is supplied to the airbag 32. As a result, the tear line 20A formed in the floor 20 of the passenger compartment ruptures under the inflation pressure of the airbag 32, and the airbag 32 inflates and deploys towards the left and right knees and shins of the occupant P seated in the vehicle seat 12.

[0048] Furthermore, as the airbag 32 inflates and deploys, a surface tether 38 connecting the upper end portion 32Uf of the front wall 32F of the inflated airbag 32 to a pair of left and right support portions 22 provided on the lower side of the floor 20 opens the tear line 20B formed in 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, this surface tether 38 relatively pulls the upper end portion 32Uf of the front wall 32F of the airbag 32 diagonally downward and rearward. In other words, this surface tether 38 forms a reaction force surface with respect to the airbag 32.

[0049] Therefore, the load from at least the left and right knees of the occupant P, which has moved forward due to inertial force, can be effectively absorbed by the airbag 32, which is relatively pulled diagonally backward and downward by the surface tether 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 from the surface tether 38, so that the airbag 32 compresses and deforms, effectively restraining at least the left and right knees of the occupant P.

[0050] Thus, according to the first embodiment, even when there is ample space in front of the left and right knees and shins of an occupant P seated in a vehicle seat 12 (i.e., there are no reaction surfaces 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 in the initial stages of a collision).

[0051] Moreover, since this surface tether 38 covers at least the upper half of the front wall 32F of the inflated and deployed airbag 32 from the front, the airbag 32 is held over a wider area while being pulled diagonally downward and rearward, compared to a configuration in which the airbag 32 is pulled diagonally downward and rearward by, for example, a pair of elongated tethers on the left and right sides. As a result, the airbag 32 can more effectively absorb the load from at least the left and right knees of the occupant P that has moved forward due to inertial force.

[0052] As a result, even if the occupant P seated in the vehicle seat 12 is not wearing a seat belt, or even if they are wearing a seat belt but are in a comfortable position with the seat back 16 tilted far back, the occupant P's knees can be effectively restrained at least on both sides. In addition, since the surface tether 38 has a simple configuration with only one piece, its manufacturing cost can also be reduced.

[0053] Furthermore, as described above, the airbag 32 and the face tether 38 deploy by rupturing the tear lines 20A and 20B formed in the floor 20. Therefore, the airbag 32 and the face tether 38 can deploy more smoothly than in a case where tear lines 20A and 20B are not formed in the floor 20.

[0054] Furthermore, the inflator 28 is provided as a single unit to supply gas to the left-right central portion of the lower end portion 32D of the airbag 32. Therefore, the shape of the airbag 32 can be made simpler compared to, for example, when the inflators 28 are provided in pairs on the left and right sides (it is not necessary to form its lower end portion 32D in a bifurcated shape to 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 parts equivalent to those in the first embodiment are denoted by the same reference numerals, 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 in that the inflators 28 are provided in pairs on the left and right so as to supply gas to both left and right ends of the lower end portion 32D of the airbag 32, and the tension members consist of a pair of left and right tethers 40, one end of which is attached to the upper end portion (upper part) 32Us of the left and right side walls 32S of the airbag 32, and the other end of which is attached to a pair of left and right support portions 22.

[0057] To explain in more detail, there are two inflators 28: a left inflator 28L and a right inflator 28R. Therefore, the lower end 32D of the airbag 32 is formed in a bifurcated shape, branching to the left and right in a plan view. In other words, the inflators 28L and 28R are connected to the bifurcated lower end 32D of the airbag 32, respectively.

[0058] According to this second embodiment, since the inflators 28 are provided in pairs on the left and right so as to supply gas to both left and right ends of the airbag 32, respectively, that is, since the inflators 28L and 28R are connected to the bifurcated lower ends 32D of the airbag 32, the airbag 32 can be inflated and deployed more quickly than, for example, when only one inflator 28 is provided.

[0059] Furthermore, 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 32Us of the left and right side walls 32S of the airbag 32, and the other end of each band tether 40 is attached to a pair of left and right support parts 22. Therefore, compared to the case where 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 parts equivalent to those in the first and second embodiments will be denoted by the same reference numerals, and detailed descriptions (including common functions) will be omitted as appropriate.

[0061] As shown in Figures 6 and 7, this third embodiment differs from the first embodiment in that the airbag 32 has a first chamber 34 that inflates and deploys diagonally rearward and upward (rearward and upward) when gas is supplied from the inflator 28, and a second chamber 36 that inflates and deploys diagonally rearward and downward (rearward and downward) from the top of the first chamber 34, i.e., toward the left and right knees and shins (at least the left and right knees) of the occupant P when gas is supplied from the first chamber 34, and the tether 40 connects the upper ends (upper parts) 34U of the left and right side walls 34S of the first chamber 34 to a pair of left and right support parts 22.

[0062] The second chamber 36 is provided on the upper part 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 delay relative to the first chamber 34. After inflation and deployment, the second chamber 36 is positioned in front of the left and right knees and shins of the occupant P.

[0063] The communication hole 35 is located approximately in the center of the second chamber 36 in both the vertical and horizontal directions. Furthermore, the second chamber 36, after inflation and deployment, is formed to be large enough to cover at least the left and right knees of the occupant P from the front (more specifically, diagonally upward and forward).

[0064] In other words, the second chamber 36, after expansion and deployment, is formed to have a width, height, and thickness that can restrain at least the left and right knees of the occupant P, who is moving forward due to inertial force during a frontal collision of the vehicle, and is compressible and deformable when pressed against at least the left and right knees of the occupant P.

[0065] Furthermore, the first chamber 34 and the second chamber 36 are each formed into a bag shape by overlapping two base fabrics and sewing their edges together. 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 together, for example, the periphery of a circularly formed communication hole 35.

[0066] According to this third embodiment, the load from at least the left and right knees of the occupant P, which has moved forward due to inertial force, can be effectively absorbed by the second chamber 36, which is pulled diagonally backward and downward 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 in the first chamber 34, which is pulled by the belt tether 40, so that the second chamber 36 is compressed and deformed, and can effectively restrain at least the left and right knees of the occupant P.

[0067] In particular, the second chamber 36 inflates and deploys from the upper part of the rear wall 34B of the first chamber 34 to restrain at least the left and right knees of the occupant P. Therefore, compared to the case where the airbag 32 is a single unit (without the first chamber 34 and the second chamber 36), the increase in the volume of the airbag 32 can be suppressed. In other words, the increase in the output of the inflator 28 can be suppressed, and the manufacturing cost can be reduced accordingly.

[0068] <Fourth Embodiment> Next, the fourth embodiment will be described. Note that parts equivalent to those in the first to third embodiments will be denoted by the same reference numerals, and detailed explanations (including common functions) will be omitted as appropriate.

[0069] As shown in Figures 8 and 9, this fourth embodiment differs from the third embodiment in that, similar to the second embodiment, the inflators 28 are provided in pairs on the left and right so as to supply gas to both left and right ends of the lower end portion 34D of the first chamber 34.

[0070] In other words, the inflator 28 is provided in two units, a left inflator 28L and a right inflator 28R, similar to the second embodiment described above. Therefore, the lower end portion 34D of the first chamber 34 is formed in a bifurcated shape, branching to the left and right in a plan view. That is, the inflators 28L and 28R are connected to the bifurcated left and right lower end portions 34D of the first chamber 34, respectively.

[0071] According to this fourth embodiment, the same effects and advantages as the third embodiment can be obtained, and similar to the second embodiment, the first chamber 34 of the airbag 32 can be inflated and deployed earlier compared to the case where, for example, a single inflator 28 is provided, and the second chamber 36 of the airbag 32 can also be inflated and deployed earlier.

[0072] <Fifth Embodiment> Finally, the fifth embodiment will be described. Note that parts equivalent to those in the first to fourth embodiments are denoted by the same reference numerals, and detailed explanations (including common functions) will be omitted as appropriate.

[0073] As shown in Figure 10, this fifth embodiment differs from the first embodiment in that each of the left and right support parts 22 is provided with a pretensioner mechanism 42 that, when activated, pulls the face tether 38, and when the vehicle seat 12 is positioned further rearward than a predetermined position, each pretensioner mechanism 42 is activated in conjunction with the deployment of the airbag 32 and face 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 moves diagonally downward and backward instantaneously when the gas generator is activated. The moving mechanism may be, for example, a mechanism composed of 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 the gas generators are configured to operate at the same time that the inflated and deployed airbags 32 restrain at least the left and right knees of the occupant P, the operation of each gas generator will cause each movement mechanism to instantly move diagonally downward and backward, and the surface tethers 38 can be instantly retracted diagonally downward and backward via each support portion 22.

[0076] According to the fifth embodiment with this configuration, as shown in the figures, even if the vehicle seat 12 is located 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 floor-mounted lower limb restraint airbag device 30 according to this embodiment has been described above based on the drawings. However, the floor-mounted lower limb restraint airbag device 30 according to this embodiment is not limited to the illustrated version, and can be modified as appropriate without departing from the spirit of the present invention.

[0078] For example, the floor 20 may be pre-equipped with rotatable airbag doors 26 and tether doors 27 instead of tear lines 20A and 20B. Also, the 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 will be formed in the floor carpet.

[0079] Furthermore, the tension member in the second to fourth embodiments may be a surface tether 38 instead of a strip tether 40. Also, the tension member in the first and fifth embodiments may be a strip tether 40 instead of a surface tether 38. Furthermore, a pretensioner mechanism 42 may be provided on each of the left and right support parts 22 in the second to fourth embodiments. In addition, in the fifth embodiment, a single pretensioner mechanism 42 may be configured to instantly pull the left and right support parts 22 diagonally downward and rearward. [Explanation of symbols]

[0080] 12 Vehicle seats 20 floors 20A Tear line (break section) 20B Tear line (break point) 22 Support part 28 Inflators 30 Floor-mounted lower limb restraint airbag device 32 airbags 34. Chamber 1 36. Chamber 2 38-sided tether (tensile member) 40. Tether (Tension Member) 42 Pretensioner mechanism P Crew

Claims

1. An airbag mounted on the lower side of the vehicle floor in the passenger compartment, which, in the event of a frontal collision, is supplied with gas from an inflator, causing the floor to split open and inflating towards at least the knees of occupants seated in the vehicle seats, A tension member connects the upper part of the airbag to a support portion provided on the lower side of the floor of the vehicle, and when the airbag inflates and deploys, causing the floor to split open and the airbag to restrain at least the knees of the occupant who is moving forward due to inertia, the tension member pulls the upper part of the airbag relatively towards the rear and lower side of the vehicle. Equipped with, The aforementioned tension member is a floor-mounted lower limb restraint airbag device, comprising a surface tether that covers at least the upper half of the front wall of the inflated and deployed airbag from the front of the vehicle.

2. An airbag mounted on the lower side of the vehicle floor of the passenger compartment, which, in the event of a frontal collision of the vehicle, is supplied with gas from an inflator, causing the floor to split open and inflating towards at least the knees of an occupant seated in a vehicle seat, A tension member connects the upper part of the airbag to a support portion provided on the lower side of the floor of the vehicle, and when the airbag inflates and deploys, causing the floor to split open and the airbag to restrain at least the knees of the occupant who is moving forward due to inertia, the tension member pulls the upper part of the airbag relatively towards the rear and lower side of the vehicle. Equipped with, The aforementioned airbag, The first chamber expands and unfolds towards the rear and upward of the vehicle when the gas is supplied from the inflator, The second chamber expands and unfolds toward at least the knee area of ​​the occupant when the gas is supplied from the first chamber, It has, A floor-mounted lower limb restraint airbag device in which the tension member connects the upper part of the first chamber and the support portion.

3. The floor-mounted lower limb restraint airbag device according to claim 2, wherein the second chamber inflates and deploys from the upper part of the rear wall of the first chamber to restrain at least the knees of the occupant.

4. The floor-mounted lower limb restraint airbag device according to claim 2 or 3, wherein the tension member is composed of a pair of left and right tethers, one end of which is attached to the upper part of the first chamber and the other end of which is attached to the support portion.

5. The floor-mounted lower limb restraint airbag device according to any one of claims 1 to 3, wherein the inflator is provided as a single unit to supply the gas to the left-right central portion of the airbag.

6. The floor-mounted lower limb restraint airbag device according to any one of claims 1 to 3, wherein the inflators are provided in a pair, left and right, to supply the gas to both left and right ends of the airbag, respectively.

7. The support portion is provided with a moving mechanism that, when activated, pulls the tension member. A floor-mounted lower limb restraint airbag device according to any one of claims 1 to 3, wherein the movement mechanism is activated in conjunction with the deployment of the airbag and the tension member when the vehicle seat is located beyond a predetermined position towards the rear of the vehicle.

8. The floor-mounted lower limb restraint airbag device according to any one of claims 1 to 3, wherein the airbag and the tension member are configured to deploy by rupturing a tearing section formed in the floor.

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