Floor-mounted lower limb restraint airbag device

Abstract

A lower limb restraint airbag device mounted on a floor is provided with: an airbag which is mounted on the lower side of the floor of a vehicle cabin and which, when a head-on collision of a vehicle occurs, is supplied with gas from an inflator; the floor panel is expanded and expanded toward at least the knees of an occupant seated on the vehicle seat by cracking the floor panel. And a tension member that connects the upper portion of the airbag and a support portion provided on the lower side of the floor. When the air bag is inflated and deployed, the floor is cracked and deployed, and at least the knees of the occupant that wants to move toward the front side of the vehicle due to inertia force are restrained by the air bag. The upper portion of the airbag is relatively stretched toward the vehicle rear side and the vehicle lower side.

Description

Technical Field

[0001] The present disclosure relates to a lower limb restraint airbag device mounted on a floor. Background Art

[0002] Conventionally, there is known an occupant protection device having a right knee airbag and a left knee airbag, which are deployed from the left and right sides of an occupant seated on a vehicle seat toward the knees of the occupant and press the left and right knees respectively (for example, see Japanese Patent Application Laid-Open No. 2018-161963). 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. Summary of the invention

[0003] However, in the occupant protection device having the above structure, only the pair of left and right knee airbags are deployed toward the center in the seat width direction, and there is no reaction force surface for each knee airbag.

[0004] Therefore, when there is a wider space in front of the knees of an occupant sitting on a vehicle seat such as a front seat that has been moved significantly to the rear, in the event of a head-on collision of the vehicle, the pair of left and right knee airbags will not be able to properly restrain the knees (lower limbs) of the occupant who is about to move forward due to inertia.

[0005] In addition, although a structure is also considered in which a restraining object that serves as a reaction force surface of each knee airbag is protruded from the floor, for example, since the front-to-back position of the vehicle seat can be changed, a sufficient restraining force cannot be obtained for the knees of the occupant depending on the front-to-back position of the vehicle seat. In this way, there is room for improvement in the lower limb restraining airbag device in the case where there is a wide space in front of the knees of the occupant sitting on the vehicle seat (no reaction force surface).

[0006] Therefore, the present disclosure provides a floor-mounted lower limb restraining airbag device that can effectively restrain the knees of an occupant seated on a vehicle seat even when there is a wide space on the vehicle front side of the knees of the occupant.

[0007] The first mode of the present disclosure involves a floor-mounted lower limb restraining airbag device comprising: an airbag which is mounted on the lower side of the floor of a vehicle compartment and is configured to be expanded and deployed toward at least the knees of an occupant seated on a vehicle seat by supplying gas from an inflator when the vehicle collides head-on; and a stretching member which connects an upper portion of the airbag and a supporting portion provided on the lower side of the floor and relatively stretches the upper portion of the airbag toward the rear side and the lower side of the vehicle when the floor is split and deployed as the airbag expands and deploys and the airbag restrains at least the knees of the occupant who is intended to move toward the front side of the vehicle due to inertia.

[0008] According to the first embodiment, when a vehicle is hit head-on, the airbag is supplied with gas from the inflator, so that the floor of the vehicle compartment is cracked and inflated and deployed toward at least the knees of an occupant sitting on a vehicle seat. In addition, as the airbag is inflated and deployed, a tension member connecting the upper portion of the inflated and deployed airbag and a support portion provided on the vehicle lower side of the floor is cracked and deployed. When the airbag restrains at least the knees of the occupant who is trying to move toward the front of the vehicle due to inertia, the tension member relatively stretches the upper portion of the airbag toward the rear side and the lower side of the vehicle.

[0009] Therefore, the airbag is relatively stretched toward the rear side and the lower side of the vehicle by the stretching component, thereby effectively bearing the load from the knees of the occupant that have moved toward the front side of the vehicle due to the inertial force. That is, when restraining the occupant, even if the airbag is pressed toward the front side of the vehicle by the knees of the occupant, the knees of the occupant can be effectively restrained by the compression deformation of the airbag because of the reaction force obtained by the stretching component. In this way, according to the present disclosure, even if there is a wider space (no reaction force surface) on the front side of the vehicle for the knees of the occupant sitting on the vehicle seat, the knees of the occupant can be effectively restrained by the airbag. In addition, the "frontal collision" mentioned here also includes the time when it is predicted (foreseeable) that the frontal collision is inevitable.

[0010] Furthermore, a floor-mounted lower limb restraining airbag device of a second aspect is the floor-mounted lower limb restraining airbag device of the first aspect, wherein the airbag and the tensile member are configured to be deployed by rupturing a rupture portion for rupture formed on the floor.

[0011] According to the second aspect, the airbag and the tensile member are deployed by rupturing the rupture portion for rupture formed on the floor. Therefore, the airbag and the tensile member are deployed more smoothly than when no rupture portion is formed on the floor.

[0012] In addition, a third type of floor-mounted lower limb restraint airbag device is that, in the floor-mounted lower limb restraint airbag device of the first or second type, the stretching component is composed of a surface strap, and the surface strap 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, the tension member is composed of a surface tie that covers at least the upper half of the front wall of the inflated and deployed airbag from the front side of the vehicle. Therefore, compared with the case where the tension member is composed of, for example, a pair of left and right elongated belt ties, the airbag is held by the tension member over a wider area and relatively stretched toward the rear side of the vehicle and the lower side of the vehicle. As a result, the load from the knee of the occupant that has moved toward the front side of the vehicle due to inertia is more effectively borne by the airbag. In addition, since the surface tie is a single piece and has a simple structure, its manufacturing cost is reduced.

[0014] In addition, a fourth type of floor-mounted lower limb restraint airbag device is that, in the floor-mounted lower limb restraint airbag device of the first or second type, the stretching component is composed of a pair of belt ties in the vehicle width direction, one end of the belt tether is mounted on the upper part of the airbag, and the other end of the belt tether is mounted on the support part.

[0015] According to the fourth aspect, the tension member is composed of a pair of belt ties, one end of which is mounted on the upper portion of the airbag, and the other end of which is mounted on the support portion. Therefore, compared with the case where the tension member is composed of a wide surface tether, for example, the miniaturization of the tension member is achieved, thereby reducing the manufacturing cost accordingly.

[0016] Furthermore, a fifth aspect of the floor-mounted lower limb restraining airbag device is the floor-mounted lower limb restraining airbag device of any one of the first to fourth aspects, wherein the inflator is singly provided so as to supply the gas to a center portion of the airbag in the vehicle width direction.

[0017] According to the fifth aspect, a single inflator is provided to supply gas to the center portion of the airbag in the vehicle width direction. Therefore, the shape of the airbag becomes simpler than when the inflators are provided as a pair of left and right inflators, for example.

[0018] In addition, the sixth 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 inflation device is arranged in a pair in the vehicle width direction in such a manner as to supply the gas to both ends of the airbag in the vehicle width direction, respectively.

[0019] According to the sixth aspect, the inflators are provided as a pair to supply gas to both ends of the airbag in the vehicle width direction, so that the airbag can be inflated and deployed earlier than when a single inflator is provided.

[0020] In addition, 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 a pretensioning mechanism is provided on the support portion for stretching the stretching component by operating, and the floor-mounted lower limb restraint airbag device is configured as follows: that is, when the vehicle seat is located on the rear side of the vehicle above a predetermined position, the pretensioning mechanism operates along with the deployment of the airbag and the stretching component.

[0021] According to the disclosure of the seventh aspect, a pretensioning mechanism is provided on the support portion to stretch the tensile member by operating, and when the vehicle seat is located at the rear side of the vehicle above the predetermined position, the pretensioning mechanism operates along with the deployment of the airbag and the tensile member. Therefore, even if the vehicle seat is located at the rear side of the vehicle above the predetermined position, the inflated and deployed airbag can be brought close to the knees of the occupant, thereby effectively restraining the knees of the occupant.

[0022] In addition, the eighth 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 seventh embodiments, wherein the airbag comprises: a first chamber, which is inflated and deployed toward the rear side and the upper side of the vehicle by being supplied with the gas from the inflation device; and a second chamber, which is inflated and deployed toward at least the knee of the occupant by being supplied with the gas from the first chamber, and the stretching component connects the upper portion of the first chamber and the support portion.

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

[0024] Therefore, the load from the passenger's knees that have moved toward the front of the vehicle due to inertia is effectively borne by the second chamber that is relatively stretched toward the rear and lower side of the vehicle via the first chamber by the stretched member. That is, when the passenger is restrained, even if the second chamber is pressed toward the front of the vehicle by the passenger's knees, the passenger's knees are effectively restrained by the compression deformation of the second chamber because the reaction force is obtained by the first chamber stretched by the stretched member.

[0025] Furthermore, a ninth aspect of the floor-mounted lower limb restraining airbag device is the floor-mounted lower limb restraining airbag device of the eighth aspect, wherein the second chamber is inflated and deployed from an upper portion of a rear wall of the first chamber to restrain at least the knees of the occupant.

[0026] According to the disclosure of the ninth aspect, the second chamber is expanded and deployed 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 a single structure (not having the first chamber and the second chamber), the increase in the capacity of the airbag is suppressed. In other words, the increase in the output of the inflator is suppressed, thereby reducing the manufacturing cost accordingly.

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

[0028] Figure 1A It is a schematic plan view showing a floor panel on which the floor-mounted lower limb restraining air bag device according to the first embodiment is mounted.

[0029] Figure 1B It is a schematic plan view showing a state in which an airbag door and a tether door of a floor on which the floor-mounted lower limb restraining airbag device according to the first embodiment is mounted are opened.

[0030] Figure 2A It is a schematic plan view showing a state of an airbag in an initial stage of deployment in the lower limb restraining airbag device mounted on the floor according to the first embodiment.

[0031] Figure 2B It is a schematic plan view showing a state in a late stage of deployment of an airbag in the lower limb restraining airbag device mounted on the floor according to the first embodiment.

[0032] Figure 3A It is a schematic side view showing a state of an airbag in an initial stage of deployment in the lower limb restraining airbag device mounted on the floor according to the first embodiment.

[0033] Figure 3B It is a schematic side view showing a state of a later stage of deployment of an airbag in the lower limb restraining airbag device mounted on the floor according to the first embodiment.

[0034] Figure 4A It is a schematic plan view showing a state of an airbag in an initial stage of deployment in a lower limb restraining airbag device mounted on a floor according to a second embodiment.

[0035] Figure 4B It is a schematic plan view showing a state of a lower limb restraining airbag device mounted on a floor according to a second embodiment at a later stage of airbag deployment.

[0036] Figure 5A It is a schematic side view showing a state of an airbag in an initial stage of deployment in a lower limb restraining airbag device mounted on a floor according to a second embodiment.

[0037] Figure 5B It is a schematic side view showing a state of a later stage of deployment of an airbag in a floor-mounted lower limb restraining airbag device according to a second embodiment.

[0038] Fig. 6A It is a schematic plan view showing a state of an airbag in an initial stage of deployment in a floor-mounted lower limb restraining airbag device according to a third embodiment.

[0039] Figure 6B It is a schematic plan view showing a state in a late stage of deployment of an airbag in a floor-mounted lower limb restraining airbag device according to a third embodiment.

[0040] Fig. 7A It is a schematic side view showing a state of an airbag in an initial stage of deployment in a lower limb restraining airbag device mounted on a floor according to a third embodiment.

[0041] Figure 7B It is a schematic side view showing a state in a late stage of deployment of an airbag in a floor-mounted lower limb restraining airbag device according to a third embodiment.

[0042] Fig. 8A It is a schematic plan view showing a state of an airbag in an initial stage of deployment in a lower limb restraining airbag device mounted on a floor according to a fourth embodiment.

[0043] Figure 8B It is a schematic plan view showing a state in a late stage of deployment of an airbag in a floor-mounted lower limb restraining airbag device according to a fourth embodiment.

[0044] Fig.9A It is a schematic side view showing a state of an airbag in an initial stage of deployment in a floor-mounted lower limb restraining airbag device according to a fourth embodiment.

[0045] Fig. 9B It is a schematic side view showing a state of a later stage of deployment of an airbag in a floor-mounted lower limb restraining airbag device according to a fourth embodiment.

[0046] Fig. 10A It is a schematic side view showing a state of an airbag in an initial stage of deployment in a lower limb restraining airbag device mounted on a floor according to a fifth embodiment.

[0047] Fig. 10B It is a schematic side view showing a state in a late stage of deployment of an airbag in a floor-mounted lower limb restraining airbag device according to a fifth embodiment. DETAILED DESCRIPTION

[0048] Hereinafter, the implementation method involved in the present disclosure will be described in detail based on the accompanying drawings. In addition, for the convenience of description, the arrow mark UP appropriately indicated in each of the accompanying drawings is set to the upper direction of the vehicle and the vehicle seat, the arrow mark FR is set to the front direction of the vehicle and the vehicle seat, and the arrow mark RH is set to 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 recorded without special description, they are set to represent the up-down, front-back, left-right in the vehicle and the vehicle seat. In addition, the left-right direction is synonymous with the vehicle width direction and the seat width direction.

[0049] <First embodiment>

[0050] First, the first embodiment is described. As shown in FIGS. 1 to 3 , the occupant restraint device 10 is composed of a vehicle seat 12 and a lower limb restraint airbag device 30 (hereinafter, sometimes simply referred to as a “lower limb restraint airbag device 30”) installed on the floor and provided for each vehicle seat 12. In addition, the “lower limb” mentioned here refers to the area from the knee to the lower side of the occupant P, including at least the knee and the shin.

[0051] The vehicle seat 12 is a front seat or a rear seat on the passenger side of an autonomous vehicle, etc., with the front side of the seat being wider in the front-rear direction. The vehicle seat 12 includes a seat cushion 14 on which an occupant sits (supporting the occupant's buttocks and thighs), a seat back 16 rotatably disposed at the rear side of the seat cushion 14 with the seat width direction as the axial direction to support the occupant's back, and a headrest 18 disposed at the upper end of the seat back 16 in a manner that can be raised and lowered to support the occupant's head.

[0052] In addition, in each of the drawings, as a model of the occupant (seat occupant) to be protected, a state in which a dummy (human dummy) 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) of a dummy (Hybrid III) for a frontal collision test. The dummy sits in a standard sitting posture prescribed by the collision test method, and the vehicle seat 12 is located at a reference setting position corresponding to the sitting posture. Hereinafter, the dummy is referred to as "occupant P".

[0053] As shown in the drawings, an occupant P sitting on the seat cushion 14 of the vehicle seat 12 is restrained on 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.

[0054] A lower limb restraining airbag device 30 is mounted below the floor panel 20 of the vehicle compartment in front of the vehicle seat 12. The lower limb restraining airbag device 30 includes an airbag 32, an inflator 28, and a module housing (not shown). The airbag 32 is normally stored in the module housing together with the inflator 28 in a folded state. The module housing is formed in a hollow substantially rectangular parallelepiped shape and is provided below the floor panel 20 of the vehicle compartment.

[0055] 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), 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.

[0056] The inflator 28 is a substantially cylindrical cylinder-type inflator of a combustion type or a cold gas type, and is arranged with its axis direction along the front-to-back direction. In addition, the inflator 28 is operated by the control device when the vehicle is in a frontal collision, 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 eccentric frontal collision such as an oblique collision and a small overlap collision.

[0057] The airbag 32, through the expansion pressure caused by the gas supplied from the inflator 28, causes the floor 20 to rupture and expand (expand and expand) toward the left and right knees and shins (at least the left and right knees) of the occupant P sitting on the vehicle seat 12, and is formed into a roughly inverted "L" shape when viewed from the side in the vehicle width direction.

[0058] The floor panel 20 has a tear line 20A formed along the left-right direction as a rupture portion for rupture, and the airbag 32 is inflated and deployed by rupturing the tear line 20A. The portion ruptured from the tear line 20A and rolled forward becomes the airbag door 26.

[0059] The inflated and deployed airbag 32 is formed to a size that can cover the left and right knees and shins of the occupant P from the front side (specifically, the oblique front upper side). 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 and shins of the occupant P that want to move forward due to inertia during a frontal collision of the vehicle, and can be compressed and deformed by being pressed by at least the left and right knees of the occupant P (refer to FIG. 2(B) and FIG. 3(B)).

[0060] The airbag 32 is formed into a bag shape by overlapping two base fabrics and sewing their peripheral edges together. The base fabric is made of, for example, a polyamide or polyester fabric. In addition, the inflator 28 is provided singly so as to supply gas to the left-right central portion of the lower end portion 32D of the airbag 32. Therefore, the airbag 32 is formed into a tapered shape whose width gradually narrows toward the lower end portion 32D when viewed from above.

[0061] Furthermore, a surface tie 38 as a tensile member is provided on the lower side of the floor 20, and the surface tie 38 is deployed upward by tearing a pair of tear lines 20B formed on the floor 20 along the front-rear direction as the airbag 32 is inflated and deployed. The surface tie 38 connects the upper end (upper part) 32Uf of the front wall 32F of the inflated and deployed airbag 32 and the support part 22 provided in a pair of left and right portions on the lower side of the floor 20 at a predetermined length or more on the rear side relative to the module case.

[0062] The face tether 38 is configured to relatively pull the upper end portion 32Uf of the front wall 32F of the airbag 32 obliquely rearward and downward (rearward and downward) when restraining at least the left and right knees of the occupant P who is trying to move forward due to inertia force by the airbag 32. In other words, the face tether 38 is configured to provide the airbag 32 with a reaction force from the front side.

[0063] The deployed face tether 38 is formed to a size that can cover at least the upper half of the front wall 32F of the inflated and deployed airbag 32 from the front side. The face tether 38 is attached to the airbag 32 by sewing the periphery of the overlapped region to cover the front wall 32F of the airbag 32.

[0064] In addition, in order to facilitate and effectively pull the airbag 32 relatively to the lower side obliquely rearward, the lower front end of the surface tether 38 is formed into a substantially right-angled triangle shape when viewed from the side. That is, the surface tether 38 is formed into a substantially obtuse isosceles triangle shape when viewed from the front by a single piece of cloth material such as polyamide or polyester. In addition, the portion that is torn from the tear line 20B and rolled outward in the seat width direction becomes the tether door 27.

[0065] In addition, as shown in FIG. 1 , the tear line 20A and the pair of tear lines 20B on the left and right are formed in a continuous manner. That is, the tear line 20A and the tear lines 20B are formed into a substantially "U" shape when viewed from above. In addition, when viewed from above, a tear line 20C of a predetermined length is formed obliquely forward and outward at the portion where the tear line 20A and the tear lines 20B intersect at right angles. As a result, the airbag door 26 and the tether door 27 have a structure that is easy to roll up.

[0066] Next, the operation of the lower limb restraining airbag device 30 according to the first embodiment having the above-described structure will be described.

[0067] 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 airbag 32. Then, the tear line 20A formed on the floor 20 of the vehicle 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 on the vehicle seat 12.

[0068] In addition, as the airbag 32 is inflated and deployed, the surface tether 38 connecting the upper end 32Uf of the front wall 32F of the inflated and deployed airbag 32 and the pair of left and right support portions 22 provided on the lower side of the floor 20 is torn and deployed. Furthermore, when the airbag 32 restrains at least the left and right knees of the occupant P who is trying to move forward due to the inertial force, the upper end 32Uf of the front wall 32F of the airbag 32 is relatively stretched obliquely rearward and downward. In other words, the surface tether 38 forms a reaction force surface with respect to the airbag 32.

[0069] Therefore, the load from at least the left and right knees of the occupant P moving forward due to the inertial force can be effectively received by the airbag 32 relatively stretched obliquely rearward and downward by the face tether 38. That is, during the occupant restraint, even if the airbag 32 is pressed forward by the left and right knees of the occupant P, the airbag 32 can be compressed and deformed to effectively restrain at least the left and right knees of the occupant P because of the reaction force obtained by the face tether 38.

[0070] In this way, according to the first embodiment, even when there is a wider space in front of the left and right knees and shins of the occupant P sitting on the vehicle seat 12 (there is no reaction surface such as the instrument panel), at least the left and right knees of the occupant P can be effectively restrained (in particular, the restraint force at the initial stage of the collision can be fully ensured).

[0071] Furthermore, 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 relatively stretched toward the oblique rear lower side while being held with a wider area, compared to a structure in which the airbag 32 is relatively stretched toward the oblique rear lower side by, for example, a pair of left and right elongated belt tethers. As a result, the load from at least the left and right knees of the occupant P moving toward the front side due to inertia can be more effectively received by the airbag 32.

[0072] Furthermore, even if the occupant P sitting on the vehicle seat 12 does not wear the seat belt, or even if the occupant P wears the seat belt, the lap belt of the seat belt is not sufficiently restrained due to the comfortable posture of the seat back 16 being tilted back greatly, at least the left and right knees of the occupant P can be effectively restrained. In addition, since the face belt 38 is a single piece, it has a simple structure, and thus its manufacturing cost can be reduced.

[0073] As described above, the airbag 32 and the surface tether 38 are deployed by rupturing the tear lines 20A and 20B formed on the floor 20. Therefore, the airbag 32 and the surface tether 38 can be deployed more smoothly than when the tear lines 20A and 20B are not formed on the floor 20.

[0074] Furthermore, the inflator 28 is provided singly so as to supply gas to the left-right center portion of the lower end portion 32D of the airbag 32. Therefore, compared with a case where the inflator 28 is provided as a pair of left and right inflators, for example, the shape of the airbag 32 can be made simple (it is not necessary to form the lower end portion 32D of the airbag 32 into a shape that branches into two branches left and right as in the second embodiment described later).

[0075] <Second embodiment>

[0076] The second embodiment will now be described. The same reference numerals are used for the same parts as those of the first embodiment, and detailed descriptions thereof (including common functions) are omitted as appropriate.

[0077] As shown in Figures 4 and 5, the second embodiment is different from the above-mentioned first embodiment in the following aspects, namely, the inflation device 28 is arranged in a pair of left and right so as to supply gas to the left and right end portions of the lower end portion 32D of the airbag 32, and the stretching component is composed of a pair of left and right belt straps 40, each of which has one end portion installed on the upper end portion (upper portion) 32Us in the left and right side walls 32S of the airbag 32 and the other end portion installed on the left and right pair of support portions 22.

[0078] Specifically, the inflator 28 includes two inflators, a left inflator 28L and a right inflator 28R. Therefore, the lower end 32D of the airbag 32 is formed into a bifurcated shape when viewed from above. That is, the inflators 28L and 28R are connected to the bifurcated lower end 32D of the airbag 32, respectively.

[0079] According to the second embodiment having such a structure, since the inflation device 28 is arranged in a pair on the left and right sides in a manner of supplying gas to the left and right end portions of the airbag 32, that is, since the inflation devices 28L and 28R are respectively connected to the left and right lower end portions 32D of the airbag 32 that are branched into two branches, the airbag 32 can be inflated and deployed earlier than when the inflation device 28 is provided alone.

[0080] Furthermore, the tension member is composed of a pair of left and right belt tethers 40. That is, one end of each belt 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 belt tether 40 is attached to the pair of left and right support parts 22. Therefore, compared with the case where the tension member is composed of, for example, a wide surface tether 38, the tension member can be miniaturized and the manufacturing cost can be reduced accordingly.

[0081] <Third Embodiment>

[0082] 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.

[0083] As shown in Figures 6 and 7, the third embodiment is different from the above-mentioned first embodiment in the following aspects, namely, the airbag 32 has a first chamber 34 that is inflated and deployed toward the obliquely rear upper side (the rear side and the upper side) by being supplied with gas from the inflation device 28, and a second chamber 36 that is inflated and deployed from the upper part of the first chamber 34 toward the obliquely rear lower side (the rear side and the lower side), that is, toward the left and right knees and shins (at least the left and right knees) of the occupant P by being supplied with gas from the first chamber 34, and the belt strap 40 connects the upper end portion (upper portion) 34U in the left and right side walls 34S of the first chamber 34 and the left and right pair of support portions 22.

[0084] The second chamber 36 is provided at the upper portion of the rear wall 34B of the first chamber 34 via the communication hole 35, and is supplied with gas from the first chamber 34 through the communication hole 35. That is, the second chamber 36 is configured to expand and deploy toward the left and right knees and shins of the occupant P with a delay of a predetermined time relative to the first chamber 34. The expanded and deployed second chamber 36 is arranged on the front side of the left and right knees and shins of the occupant P.

[0085] The communication hole 35 is provided at the substantially central portion in the vertical direction and the substantially central portion in the horizontal direction of the second chamber 36. The inflated and expanded second chamber 36 is formed to a size that can cover at least the left and right knees of the occupant P from the front side (specifically, the oblique upper front side).

[0086] In other words, the inflated and expanded second chamber 36 is formed to have a width, height, and thickness that can restrain the left and right knees and at least the left and right knees of the occupant P that want to move forward due to inertia force during a head-on collision of the vehicle, and can be compressed and deformed by being pressed by at least the left and right knees of the occupant P.

[0087] 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 together. The base fabric is made of a polyamide or polyester fabric. And, for example, the periphery of the communicating hole 35 formed into a circular shape is sewn together, so that the front wall 36F of the second chamber 36 is attached to the rear wall 34B of the first chamber 34.

[0088] According to the third embodiment having such a structure, the load from at least the left and right knees of the occupant P moving forward due to the inertial force can be effectively received by the second chamber 36 relatively stretched obliquely rearward and downward by the belt tether 40 through the first chamber 34. That is, during the occupant restraint, even if the second chamber 36 is pressed forward by the left and right knees of the occupant P, the reaction force is obtained by the first chamber 34 stretched by the belt tether 40, so that at least the left and right knees of the occupant P can be effectively restrained by compressing and deforming the second chamber 36.

[0089] In particular, the second chamber 36 is inflated and deployed from the upper portion of the rear wall 34B of the first chamber 34, thereby restraining at least the left and right knees of the occupant P. Therefore, compared with a case where the airbag 32 is a single structure (not having the first chamber 34 and the second chamber 36), an increase in the capacity of the airbag 32 can be suppressed. In other words, an increase in the output of the inflator 28 can be suppressed, and the manufacturing cost can be reduced accordingly.

[0090] <Fourth embodiment>

[0091] The fourth embodiment will now be described. The same reference numerals are used for the same parts as those of the first to third embodiments, and detailed descriptions thereof (including common functions) are appropriately omitted.

[0092] As shown in Figures 8 and 9, the fourth embodiment is different from the third embodiment in that, similar to the second embodiment, the inflator 28 is arranged in a pair of left and right portions so as to supply gas to both ends in the left and right directions of the lower end portion 34D of the first chamber 34, respectively.

[0093] That is, the inflator 28 is provided with two inflators 28L on the left and 28R on the right, similarly to the second embodiment. Therefore, the lower end 34D of the first chamber 34 is formed into a shape that branches into two branches in a plan view. That is, the inflators 28L and 28R are connected to the left and right lower ends 34D of the first chamber 34 that branch into two branches, respectively.

[0094] According to the fourth embodiment with such a structure, the same effects as those of the above-mentioned third embodiment can be obtained, and similarly to the above-mentioned second embodiment, compared with the case where the inflation device 28 is, for example, provided alone, the first chamber 34 of the airbag 32 can be inflated and deployed earlier, and the second chamber 36 of the airbag 32 can be inflated and deployed earlier.

[0095] <Fifth Embodiment>

[0096] Finally, the fifth embodiment will be described. In addition, the same reference numerals are used for the same parts as those of the first to fourth embodiments, and detailed descriptions thereof (including common functions) are omitted as appropriate.

[0097] As shown in FIG. 10 , the fifth embodiment is different from the first embodiment in that a pretensioning mechanism 42 for stretching the face tether 38 by operating is provided on each of the left and right pair of support portions 22, and the fifth embodiment is configured such that when the vehicle seat 12 is located on the rear side above a predetermined position, the airbag 32 and the face tether 38 are deployed, thereby causing each pretensioning mechanism 42 to operate.

[0098] The pre-tensioning mechanism 42 is a well-known mechanism, for example, having a gas generator (not shown) and a moving mechanism (not shown) that is moved diagonally to the rear and lower side instantaneously by the operation of the gas generator. The moving mechanism may be a mechanism composed of a rack and a pinion, for example. In addition, the support portion 22 to which the lower end of the face strap 38 is mounted is mechanically connected to the moving mechanism.

[0099] Therefore, if the gas generators are configured to operate at a timing when the inflated and deployed airbag 32 restrains at least the left and right knees of the occupant P, the operation of the gas generators will cause the moving mechanisms to move instantaneously to the lower and oblique rear side, thereby being able to instantaneously pull the surface tether 38 to the lower and oblique rear side via the support portions 22.

[0100] According to the fifth embodiment of such a structure, as shown in the figure, even if the vehicle seat 12 is located on the rear side above a predetermined position (for example, the position shown in Figures 2 to 9), compared with the above-mentioned first to fourth embodiments, the inflated and deployed airbag 32 can be closer to at least the left and right knees of the occupant P, thereby effectively restraining at least the left and right knees of the occupant P.

[0101] Although the above text describes the floor-mounted lower limb restraint airbag device 30 involved in this embodiment based on the accompanying drawings, the floor-mounted lower limb restraint airbag device 30 involved in this embodiment is not limited to the situation shown in the drawings, and appropriate design changes can be made without departing from the scope of the main purpose of the present disclosure.

[0102] For example, the following method may be adopted, that is, instead of providing the tear line 20A and the tear line 20B on the floor panel 20, the airbag door 26 and the tether door 27 which are configured to be rotatable may be provided in advance. In addition, the floor panel 20 may be a floor carpet instead of a floor panel. In this case, the module case may be provided on the upper side of the floor panel (between the floor panel and the floor carpet), and the tear line may be formed on the floor carpet.

[0103] In addition, the tension member in the second to fourth embodiments may be provided as the surface strap 38 instead of the belt strap 40. In addition, the tension member in the first and fifth embodiments may be provided as the belt strap 40 instead of the surface strap 38. In addition, the following method may be adopted, that is, the left and right pair of support parts 22 in the second to fourth embodiments may be provided with a pre-tightening mechanism 42 respectively. In addition, in the fifth embodiment, it may be configured so that the left and right pair of support parts 22 are instantly pulled obliquely rearward and downward by a single pre-tightening mechanism 42.

Claims

1. A lower limb restraint airbag device mounted on a floor, comprising: An airbag is mounted on the lower side of the floor of a vehicle compartment and, when a frontal collision of the vehicle occurs, gas is supplied from an inflator, thereby causing the floor to rupture and inflate and deploy toward at least the knees of an occupant seated on a vehicle seat; a stretching member that connects the upper portion of the airbag and a supporting portion provided on the lower side of the floor, and relatively stretches the upper portion of the airbag toward the rear side and the lower side of the vehicle when the floor is cracked and deployed as the airbag inflates and deploys, and the airbag restrains at least the knees of the occupant who intends to move toward the front side of the vehicle due to inertia.

2. The floor-mounted lower limb restraining airbag device according to claim 1, wherein: The airbag and the tensile member are configured to be deployed by rupturing a rupture portion for rupture formed on the floor.

3. The lower limb restraint airbag device installed on the floor according to claim 1 or claim 2, wherein: The tensile 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 a vehicle front side.

4. The lower limb restraint airbag device installed on the floor according to claim 1 or claim 2, wherein: The tension member is composed of a pair of belt tethers in the vehicle width direction, one end of the belt tether is attached to the upper portion of the airbag, and the other end of the belt tether is attached to the support portion.

5. The lower limb restraint airbag device installed on the floor according to claim 1 or claim 2, wherein: The inflator is provided singly so as to supply the gas to a center portion of the airbag in a vehicle width direction.

6. The lower limb restraining airbag device installed on the floor according to claim 1 or claim 2, wherein: The inflators are provided as a pair in the vehicle width direction so as to supply the gas to both ends of the airbag in the vehicle width direction, respectively.

7. The lower limb restraint airbag device installed on the floor according to claim 1 or claim 2, wherein: The support portion is provided with a pre-tightening mechanism for stretching the stretching member by operating. The floor-mounted lower limb restraining airbag device is configured such that when the vehicle seat is located at a rear side of the vehicle above a predetermined position, the pretensioner mechanism is activated along with the deployment of the airbag and the tension member.

8. The lower limb restraint airbag device installed on the floor according to claim 1 or claim 2, wherein: The airbag comprises: a first chamber that is inflated and deployed toward the rear side of the vehicle and the upper side of the vehicle by being supplied with the gas from the inflator; a second chamber that is inflated and deployed toward at least the knee of the occupant by being supplied with the gas from the first chamber, The tension member connects the upper portion of the first chamber and the support portion.

9. The floor-mounted lower limb restraining airbag device according to claim 8, wherein: The second chamber is inflated and deployed from an upper portion of a rear wall of the first chamber, and restrains at least the knees of the occupant.

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