Cushion airbag device

Abstract

To provide a cushion airbag device capable of suppressing a reduction in ride comfort during normal vehicle travel, reducing the downward displacement of a passenger during a vehicle collision, and thereby preventing a decrease in waist restraining force by a lap belt of a seat belt.SOLUTION: A cushion airbag device 10 comprises: a cushion airbag 30 which is installed at a lower section of a seat cushion of a vehicle seat and expands in a vertical direction with gas supplied from a pressure storage tank 50; a control valve 54 which is installed in first piping 52 communicating the cushion airbag 30 with the pressure storage tank 50 and adjusts internal pressure of the cushion airbag 30; an exhaust valve 58 which is installed in the first piping 52 between the control valve 54 and the cushion airbag 30 and exhausts the gas from inside the cushion airbag 30; and a switch valve 64 which is installed in second piping 62 communicating the cushion airbag 30 with the pressure storage tank 50 and is opened during a vehicle collision.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a cushion airbag device. [Background technology]

[0002] Vehicle seats in which the buttocks support area of the seat cushion pad is supported by an air cushion consisting of two air bags, one above the other, placed on a recess in the seat cushion frame have been known for some time (see, for example, Patent Document 1). In this vehicle seat, in the event of a vehicle collision, the air in the air bags is quickly released, causing the air cushion to contract and the buttocks support area of the seat cushion pad to instantly collapse, thereby preventing the submarine phenomenon from occurring. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-268692 Summary of the Invention [Problem to be solved by the invention]

[0004] However, if the air in the air bag is suddenly released during a vehicle collision, causing the air cushion to contract and the buttocks support area of the seat cushion pad to instantly collapse, the occupant's hips will be instantly displaced downward in the vehicle, increasing the relative displacement between the lap belt of the seat belt and the occupant's hips, which could reduce the hip restraining force of the lap belt. Also, if the buttocks support area of the seat cushion pad is always supported by the air cushion, the hardness of the seat cushion will increase, which could impair ride comfort (sitting comfort) during normal vehicle driving.

[0005] Therefore, an object of the present invention is to provide a cushion airbag device that can suppress a decrease in ride comfort during normal vehicle driving, reduce the amount of displacement of an occupant downward in the event of a vehicle collision, and suppress a decrease in the waist restraining force of the lap belt of the seat belt. [Means for solving the problem]

[0006] In order to achieve the above object, a cushion airbag device of a first aspect according to the present invention includes: a cushion airbag that is provided under a seat cushion of a vehicle seat and that expands vertically when gas is supplied from an accumulator tank; a control valve that is provided in a first pipe that communicates the cushion airbag with the accumulator tank and that adjusts the internal pressure of the cushion airbag; an exhaust valve that is provided in the first pipe between the control valve and the cushion airbag and that exhausts the gas from inside the cushion airbag; and a switching valve that is provided in a second pipe that communicates the cushion airbag with the accumulator tank and that opens in the event of a vehicle collision.

[0007] According to a first aspect of the invention, a cushion airbag is provided under a seat cushion of a vehicle seat. The cushion airbag is configured to be inflated vertically by gas supplied from an accumulator tank. A control valve for adjusting the internal pressure of the cushion airbag is provided in a first pipe connecting the cushion airbag to the accumulator tank, and an exhaust valve for exhausting gas from inside the cushion airbag is provided in the first pipe between the control valve and the cushion airbag. Therefore, during normal vehicle driving, the internal pressure of the cushion airbag can be adjusted (including a state where no gas is contained), and a decrease in ride comfort is suppressed.

[0008] In addition, a switching valve that opens in the event of a vehicle collision is provided in the second pipe that connects the cushion airbag and the pressure accumulator tank. In other words, gas is instantly supplied from the pressure accumulator tank to the cushion airbag in the event of a vehicle collision. This reduces the amount of downward displacement of the occupant in the event of a vehicle collision, and suppresses a decrease in the waist restraining force of the lap belt of the seat belt. Note that "in the event of a vehicle collision" in this invention includes not only when a vehicle collision is detected, but also when a vehicle collision is predicted. Also, "gas" in this invention includes air.

[0009] Furthermore, a cushion airbag device according to a second aspect of the present invention includes: a cushion airbag that is provided under a seat cushion of a vehicle seat and that expands vertically when gas is supplied from an accumulator tank; a control valve that is provided in a pipe that connects the cushion airbag to the accumulator tank and that adjusts the internal pressure of the cushion airbag; an exhaust valve that is provided in the pipe between the control valve and the cushion airbag and that exhausts the gas from inside the cushion airbag; and an inflator that is activated in the event of a vehicle collision and supplies gas into the inside of the cushion airbag.

[0010] According to a second aspect of the invention, a cushion airbag is provided under a seat cushion in a vehicle seat. This cushion airbag is configured to be inflated vertically by gas supplied from an accumulator tank. A control valve for adjusting the internal pressure of the cushion airbag is provided in a pipe connecting the cushion airbag to the accumulator tank, and an exhaust valve for exhausting gas from inside the cushion airbag is provided in a pipe between the control valve and the cushion airbag. Therefore, during normal vehicle driving, the internal pressure of the cushion airbag can be adjusted (including a state where no gas is contained), and a decrease in ride comfort is suppressed.

[0011] Furthermore, in the event of a vehicle collision, an inflator is activated to supply gas to the interior of the cushion airbag. In other words, gas is instantly supplied from the inflator to the cushion airbag in the event of a vehicle collision. This reduces the amount of downward displacement of the occupant in the event of a vehicle collision, and suppresses a decrease in the waist restraining force of the lap belt of the seat belt. Note that "in the event of a vehicle collision" in this invention includes not only when a vehicle collision is detected, but also when a vehicle collision is predicted. Furthermore, "gas" in this invention also includes air.

[0012] A cushion airbag device of a third aspect according to the present invention is the cushion airbag device of the first aspect, wherein the switching valve is a mechanical valve that includes a partition wall that can close the second piping and a stopper that supports the partition wall, and in the event of a vehicle collision, the support of the partition wall by the stopper is instantly released.

[0013] According to the third aspect of the invention, the switching valve is a mechanical valve including a partition wall that can close the second pipe and a stopper that supports the partition wall, and the support of the partition wall by the stopper is instantaneously released in the event of a vehicle collision. Therefore, compared to when the switching valve is an electromagnetic valve, gas is supplied to the cushion airbag more quickly, and the lap belt of the seat belt can restrain the lumbar region earlier.

[0014] Furthermore, a cushion airbag device of a fourth aspect according to the present invention is the cushion airbag device of any one of the first to third aspects, and when the vertical acceleration of the vehicle body exceeds a predetermined threshold value while the vehicle is traveling, the control valve is opened for a predetermined time.

[0015] According to the fourth aspect of the invention, when the vehicle body vertical acceleration exceeds a predetermined threshold while the vehicle is traveling, the control valve is opened for a predetermined time. In other words, the cushion airbag is inflated at a low internal pressure. Therefore, deterioration of ride comfort when the vehicle is traveling on rough roads is effectively suppressed.

[0016] Furthermore, a cushion airbag device of a fifth aspect according to the present invention is a cushion airbag device of any one of the first to fourth aspects, in which the cushion airbag is configured by two pieces of base fabric that are sewn along the outer peripheral edges and folded in half along a fold line so as to be stacked one on top of the other, has an air intake path along the fold line and an air intake port at one end of the fold line, and is fixed to an erection member erected between side frames that constitute the seat cushion with the fold line positioned on the front side of the seat.

[0017] According to a fifth aspect of the invention, a cushion airbag is constructed by stacking two pieces of base fabric, one above the other, by sewing along the outer periphery and folding the two pieces in half along the fold lines. The cushion airbag has an air intake passage along the fold lines and an air intake port at one end of the fold lines, and is fixed to a mounting member installed between the side frames that form the seat cushion with the fold lines positioned on the front side of the seat. Therefore, a cushion airbag with a limited volume can be made thicker. This large thickness difference effectively reduces the amount of displacement of the occupant downward in the event of a vehicle collision and effectively prevents a decrease in the lap belt's restraining force on the lumbar region. [Effects of the Invention]

[0018] As described above, according to the present invention, it is possible to suppress a decrease in ride comfort performance during normal vehicle driving, and to reduce the amount of displacement of the occupant downward in the event of a vehicle collision, thereby suppressing a decrease in the waist restraining force of the lap belt of the seat belt. [Brief explanation of the drawings]

[0019] [Figure 1] 1A is a schematic side cross-sectional view showing the internal structure of a vehicle seat equipped with a cushion airbag according to the present embodiment, and FIG. 1B is a schematic plan view showing the internal structure of a vehicle seat equipped with a cushion airbag according to the present embodiment as a partially enlarged side view. [Figure 2]1A is a schematic perspective view showing a cushion airbag according to the present embodiment, and FIG. 1B is a schematic development view showing a cushion airbag according to the present embodiment. [Figure 3] 1A is a schematic diagram showing the configuration of a cushion airbag device according to the present embodiment, and FIG. 1B is a schematic diagram showing the configuration of a cushion airbag device according to a modified example of the present embodiment. [Figure 4] 1A and 1B are schematic diagrams illustrating the switching valve of the cushion airbag device according to the present embodiment before and after gas is supplied to the cushion airbag device according to the present embodiment. [Figure 5] 1A and 1B are schematic side views showing a state before and after gas is supplied to the cushion airbag according to the present embodiment, respectively. [Figure 6] 4 is a flowchart showing an operation process of the cushion airbag device according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0020] 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 seat, the arrow FR indicates the forward direction of the vehicle seat, and the arrow RH indicates the rightward direction of the vehicle seat. Therefore, in the following description, unless otherwise specified, when the directions of up / down, front / rear, and left / right are mentioned, they refer to the up / down, front / rear, and left / right of the vehicle seat. Furthermore, the left / right direction is synonymous with the seat width direction.

[0021] 1(A), a cushion airbag 30 constituting a cushion airbag device 10 according to this embodiment is provided under a seat cushion 14 of a vehicle seat 12, for example, a rear seat of a vehicle (not shown). The vehicle seat 12 is a bench seat, and the seat cushion 14 includes a base member 16 made of, for example, expanded polypropylene (EPP) and a cushion pad 18 made of urethane foam.

[0022] 1(B), the vehicle seat 12 has a seat frame 22 extending in the seat width direction in a plan view, and side frames 24 bending and extending rearward from both left and right end portions of the seat frame 22. The seat frame 22 and the side frames 24 are fixed to a vehicle floor 20 (see FIG. 1(A)), and seat pans 26 having a predetermined symmetrical shape are installed between the rear surfaces of the left and right sides of the seat frame 22 and the inner side surfaces of the side frames 24 in the seat width direction.

[0023] A cylindrical anti-submarine reinforcement (hereinafter referred to as a "submarine reinforcement 28") is installed as an installation member between the left and right seat pans 26. In this embodiment, the seat pan 26 is also considered to be part of the side frame 24. Therefore, it can be said that the submarine reinforcement 28 is installed between the left and right side frames 24.

[0024] The cushion airbag 30 is attached to the submarine reinforcement 28 with a metal or resin fixing band 40, bolts 46, and nuts 48. Specifically, as shown in Figures 2(A) and 2(B), the cushion airbag 30 is made up of two silicone-coated base fabrics 32 that are sewn along the outer periphery and folded in half along fold line C, so that they are stacked one on top of the other, and the tip end 30A on the upper side is sewn to the lower side.

[0025] The cushion airbag 30 has air intake passages 34 that are generally L-shaped in plan view and extend along the fold line C on both sides in the longitudinal direction of the fold line C. The cushion airbag 30 also has air intake ports 36 at one end in the longitudinal direction of the fold line C for supplying gas toward each air intake passage 34. Therefore, gas supplied from the air intake ports 36 passes through each air intake passage 34 and is ejected toward the center of the upper and lower sides of the cushion airbag 30. Note that the term "gas" in this embodiment also includes air.

[0026] 2(A), the cushion airbag 30 is attached with a plurality of (e.g., three) fixing tabs 38 sewn at predetermined intervals along the fold lines C. Each fixing tab 38 is formed, for example, in a substantially rectangular shape in plan view, with a circular through-hole 38A formed in the center thereof. The cushion airbag 30 is arranged so that each fixing tab 38 (fold line C) is located on the front side, and each fixing tab 38 is sandwiched from above and below by a flange portion 44 (described later) of a fixing band 40 shown in FIG. 1(B).

[0027] The fixing band 40 has a ring portion 42 that is roughly C-shaped in side view and is fitted to the submarine reinforcement 28, and a pair of flange portions 44 that are roughly rectangular in plan view and extend radially outward from the ends of the ring portion 42, and a circular through hole (not shown) is formed in the center of each flange portion 44.

[0028] Therefore, each fixing tab 38 is sandwiched from above and below by a pair of flange portions 44 of the fixing band 40, and a bolt 46 is inserted into a through-hole (not shown) and a through-hole 38A (see FIG. 2(A)) that communicate with each other, and a nut 48 is screwed onto the shaft of the bolt 46, thereby fixing the fixing tab 38 to the submarine reinforcement 28. In this way, the cushion airbag 30 is attached to the submarine reinforcement 28.

[0029] The cushion airbag 30, with the fixing tabs 38 attached to the submarine reinforcement 28, is disposed between the base member 16 and the cushion pad 18 that constitute the seat cushion 14, as shown in Figures 1(A) and 5, and is in a state where no gas is contained inside during normal vehicle driving. When gas is supplied inside, the cushion airbag 30 inflates in the vertical direction, and as shown in Figure 5(B), it lifts up a part of the cushion pad 18 (the front part of the buttocks of the occupant P).

[0030] 3(A), a vehicle (or a vehicle seat 12) is provided with a high-pressure tank 50 as an accumulator tank that is pressurized by a compressor 60, and the high-pressure tank 50 and the cushion airbag 30 are connected in communication with each other via a first pipe 52. A control valve (solenoid valve) 54 that adjusts the internal pressure of the cushion airbag 30 is provided in the first pipe 52, and when the control valve 54 is opened, gas is supplied from the high-pressure tank 50 to the inside of the cushion airbag 30, causing the cushion airbag 30 to inflate in the vertical direction.

[0031] Furthermore, a branch pipe 56 is integrally provided in the first pipe 52 between the control valve 54 and the cushion airbag 30, and the branch pipe 56 is provided with an exhaust valve 58 for exhausting gas from the inside of the cushion airbag 30. The high-pressure tank 50 and the cushion airbag 30 are connected in communication with each other by a second pipe 62, and the inner diameter of the second pipe 62 is formed to be larger than the inner diameter of the first pipe 52. The second pipe 62 is provided with a switching valve 64 that opens in the event of a vehicle collision.

[0032] In this embodiment, "at the time of a vehicle collision" includes not only when a vehicle collision is detected but also when a vehicle collision is predicted (estimated). Furthermore, "at the time of emergency vehicle braking," which will be described later, includes not only when emergency vehicle braking is detected but also when emergency vehicle braking is predicted (estimated). Furthermore, the control valve 54, the exhaust valve 58, and the switching valve 64 are each electrically connected to a control device (ECU) 70, and are controlled to open and close under the control of the control device 70.

[0033] Here, as shown in Figure 4(A), for example, the switching valve 64 is a mechanical valve configured to include a partition wall 66 of a predetermined thickness that is large enough to close the passage inside the second piping 62, and a stopper 68 of a predetermined size (having an area larger than the area of an opening 62A described below) that supports the partition wall 66 from the downstream side in the outflow direction of the gas (hereinafter simply referred to as the "downstream side") so that the partition wall 66 does not collapse due to the high-pressure gas flowing out of the high-pressure tank 50.

[0034] The partition wall 66 is supported rotatably about a rotation shaft 67 whose axial direction is perpendicular to the extension direction of the second piping 62 in a plan view, and one end of a tension coil spring 78 serving as a return biasing member is attached to a wall surface 66A at the upper end of the partition wall 66 on the upstream side in the gas outflow direction (hereinafter simply referred to as the "upstream side"). The other end of the tension coil spring 78 is attached to an upper inner wall of the second piping 62 upstream of the partition wall 66.

[0035] The stopper 68 is provided on the upper inner wall of the second piping 62 downstream of the partition wall 66 so as to be slidable along the extension direction of the second piping 62. A hollow case 72 is provided integrally with the upper part of the second piping 62 downstream of the partition wall 66. One end (upper end) of a compression coil spring 74 serving as a protruding biasing member is attached to the inner surface of an upper wall 72U of the case 72, and the other end (lower end) of the compression coil spring 74 is attached to the upper end surface of a substantially flat plate-shaped restricting member 76.

[0036] That is, the restricting member 76 is biased downward by the compression coil spring 74, and protrudes downward from an opening 72A formed in a bottom wall 72D of the case 72 and an opening 62A formed in the upper part of the second pipe 62. A downstream end face 68B of the stopper 68 abuts against an upstream wall face 76A at the lower end of the restricting member 76 that protrudes from the opening 72A in the bottom wall 72D and the opening 62A in the second pipe 62.

[0037] A downstream wall surface 76B at the lower end of the restricting member 76 abuts against or is close to an upstream end surface 69A of a restricting member 69 fixed to the upper inner wall of the second pipe 62. As shown in FIG. 4(B), this restricting member 69 is configured to restrict the stopper 68 from sliding downstream more than necessary.

[0038] In this state, an upstream end surface 68A of the stopper 68 abuts against a downstream wall surface 66B at the upper end of the partition wall 66. This results in a configuration in which the partition wall 66 is supported by the stopper 68 to prevent it from collapsing downstream due to the high-pressure gas flowing out of the high-pressure tank 50.

[0039] Furthermore, a flange portion 77 is integrally formed on the upper portion of the restricting member 76, and the outer peripheral end face of the flange portion 77 abuts against the inner surface of the side wall 72S of the case 72. Explosives K are filled between the flange portion 77 of the restricting member 76 and the bottom wall 72D of the case 72, and an ignition device (not shown) for igniting the explosives K is provided in the case 72. The ignition device is electrically connected to the control device 70 (see FIG. 3(A)).

[0040] Therefore, in the event of a vehicle collision, as shown in Figure 4(B), the ignition device is controlled by the control device 70 to ignite the explosives K, causing the regulating member 76 to instantly rise within the case 72 via the flange portion 77, and the upstream wall surface 76A at the lower end of the regulating member 76 protruding from the opening 72A of the lower wall 72D and the opening 62A of the second pipe 62 instantly detaches from the downstream end surface 68B of the stopper 68.

[0041] As a result, the support of the partition wall 66 by the stopper 68 is instantaneously released, and the partition wall 66 is pushed from the upstream side by the high-pressure gas, causing it to collapse, and the high-pressure gas is instantly supplied into the cushion airbag 30. When the partition wall 66 collapses, the stopper 68 is also pushed by the partition wall 66 and slides downstream. In other words, the opening 62A of the second pipe 62 is closed by the stopper 68. Therefore, the high-pressure gas does not leak from the second pipe 62.

[0042] Furthermore, when all of the high-pressure gas has been supplied to the interior of the cushion airbag 30, the partition wall 66 returns to its original state by the biasing force of the tension coil spring 78. That is, as shown in Figure 4(A), the second piping 62 is closed. In this way, the switching valve 64 can be reused by filling the case 72 with explosives K again.

[0043] Next, the operation of the cushion airbag device 10 according to this embodiment configured as above will be described.

[0044] As described above, the cushion airbag 30 is disposed between the base member 16 and the cushion pad 18 that constitute the seat cushion 14. As shown in Fig. 5(A), the cushion airbag 30 is in a state where no gas is contained (where gas is exhausted) during normal vehicle driving. That is, as shown in Fig. 6, the control valve 54 and the exhaust valve 58 are closed (step S1), and the occupant P seated on the seat cushion 14 is supported by the base member 16 and the cushion pad 18.

[0045] Therefore, during normal vehicle driving, it is possible to prevent the hardness of the seat cushion 14 from being increased more than necessary by the cushion airbag 30, and to prevent the ride comfort (sitting comfort) performance of the seat cushion 14 from being impaired by the seat cushion 14 for the occupant P. In other words, since the internal pressure of the cushion airbag 30 can be adjusted (including a state where no gas is filled) during normal vehicle driving, it is possible to suppress or prevent a decrease in the ride comfort (sitting comfort) performance.

[0046] Next, in this state, in step S2, it is determined whether the acceleration (G) in the longitudinal direction of the vehicle is equal to or greater than a predetermined first threshold, and if a frontal collision of the vehicle is detected (or predicted) and equal to or greater than the first threshold, the switching valve 64 is instantaneously opened (step S3), as shown in Fig. 4(B). As a result, gas is instantaneously supplied from the high-pressure tank 50 to the inside of the cushion airbag 30, and the cushion airbag 30 is inflated in the vertical direction, as shown in Fig. 5(B).

[0047] That is, a part of the cushion pad 18 constituting the seat cushion 14 (the part in front of the buttocks of the occupant P) rises. Therefore, the downward displacement of the occupant P in the event of a vehicle collision can be reduced, and a reduction in the waist restraining force of the lap belt 13A of the seat belt 13 can be suppressed.

[0048] On the other hand, if it is determined in step S2 that the longitudinal acceleration (G) of the vehicle is less than a predetermined first threshold, it is determined in step S4 whether the longitudinal acceleration (G) of the vehicle is equal to or greater than a predetermined second threshold that is smaller than the first threshold, and if emergency braking that results in the acceleration being equal to or greater than the second threshold is detected (or predicted), the control valve 54 is opened (step S5). At this time, the control valve 54 is kept open for a relatively long time, and a relatively large amount of gas is supplied from the high-pressure tank 50 to the inside of the cushion airbag 30. That is, the internal pressure of the cushion airbag 30 becomes high.

[0049] Therefore, the downward displacement of the occupant P during emergency braking of the vehicle can be reduced, and a decrease in the waist restraining force of the lap belt 13A of the seat belt 13 can be suppressed. After emergency braking of the vehicle is completed, the exhaust valve 58 is opened to exhaust gas from inside the cushion airbag 30 (step S6). Then, in step S4, it is determined again whether the acceleration (G) in the longitudinal direction of the vehicle is equal to or greater than the predetermined second threshold value.

[0050] On the other hand, if it is determined in step S4 that the acceleration (G) in the longitudinal direction of the vehicle is less than a predetermined second threshold, then in step S7, it is determined by an on-board camera (not shown) or the like whether or not there are any irregularities on the road surface that are greater than or equal to a predetermined value, and if there are no irregularities, the process returns to step S1. If there are any irregularities, then in step S8, it is determined whether or not the acceleration (G) in the vertical direction of the vehicle is greater than or equal to a predetermined threshold, and if it is determined that the acceleration is greater than or equal to the threshold, the control valve 54 is opened for a predetermined time (step S9).

[0051] That is, the opening time of the control valve 54 at this time is shorter than the opening time at step S5, and the amount of gas supplied from the high-pressure tank 50 to the inside of the cushion airbag 30 is small. Therefore, the internal pressure of the cushion airbag 30 becomes low, and the cushion airbag 30 becomes a soft (low hardness) cushion airbag.

[0052] Therefore, when the vehicle is traveling on a rough road with a road surface having more than a predetermined level of unevenness, the deterioration of ride comfort can be effectively suppressed compared to when the internal pressure of the cushion airbag 30 is set to a high pressure and the cushion airbag is made to have a high hardness. Note that, in step S8, if the vertical acceleration (G) of the vehicle is determined to be less than the predetermined threshold, the exhaust valve 58 is opened (step S10), and the process returns to step S1.

[0053] As described above, the cushion airbag device 10 according to this embodiment can suppress a decrease in the ride comfort of the occupant P during normal vehicle driving, and can also reduce the amount of downward displacement of the occupant P during a vehicle collision, thereby suppressing a decrease in the waist restraining force of the lap belt 13A of the seat belt 13. In other words, this embodiment can ensure both ride comfort during normal vehicle driving and suppress or prevent the occurrence of the submarine phenomenon during a vehicle collision.

[0054] The cushion airbag 30 is constructed by stacking two pieces of base fabric 32 one above the other by sewing along the outer periphery and folding in half along the fold line C. The cushion airbag 30 has an air intake path 34 along the fold line C and an air intake port 36 at one end of the fold line C, and is fixed to the submarine reinforcement 28 with the fold line C positioned on the forward side.

[0055] Therefore, the cushion airbag 30 has a limited volume, but its thickness can be increased, and the large thickness difference effectively reduces the downward displacement of the occupant P during a vehicle collision or emergency braking of the vehicle, and effectively suppresses a decrease in the waist restraining force of the lap belt 13A of the seat belt 13.

[0056] The switching valve 64 is configured to include a partition 66 that can close the passage of the second pipe 62 and a stopper 68 that supports the partition 66, and is a mechanical valve that instantly releases the support of the partition 66 by the stopper 68 in the event of a vehicle collision. Therefore, compared to when the switching valve 64 is an electromagnetic valve, for example, the supply of gas to the cushion airbag 30 can be executed more quickly, and the lap belt 13A of the seat belt 13 can restrain the lumbar region earlier.

[0057] The cushion airbag device 10 according to this embodiment operates as described above, but the cushion airbag device 10 may also have the configuration shown in Fig. 3(B). That is, the second pipe 62 may be eliminated, and the inflator 80 may be mechanically connected to the cushion airbag 30, and the inflator 80 may be electrically connected to the control device 70.

[0058] According to this, in the event of a vehicle collision, gas can be instantly supplied from the inflator 80 to the inside of the cushion airbag 30 under the control of the control device 70. Therefore, similarly to the above, the amount of downward displacement of the occupant P in the event of a vehicle collision can be reduced, and a reduction in the waist restraining force of the lap belt 13A of the seat belt 13 can be suppressed. In other words, the occurrence of the submarine phenomenon can be suppressed or prevented.

[0059] 6 becomes "inflator activation" instead of "switching valve open." Also, in this case, there is only one pipe that communicates between the high-pressure tank 50 and the cushion airbag 30, and therefore it is referred to as "piping 52" instead of "first pipe 52." That is, in this case, a control valve 54 is provided in the pipe 52, and a branch pipe 56 is provided integrally with the pipe 52 between the control valve 54 and the cushion airbag 30.

[0060] Although the cushion airbag device 10 according to the present embodiment has been described above with reference to the drawings, the cushion airbag device 10 according to the present embodiment is not limited to the one shown in the drawings, and the design can be modified as appropriate within the scope of the gist of the present invention. For example, the position of the fold line C when folding the cushion airbag 30 in half can be changed to suit the structure of the seat cushion 14 of the vehicle seat 12 (the shape and inclination of the base member 16 and the cushion pad 18).

[0061] Furthermore, the vehicle seat 12 in this embodiment may be a front seat configured as a captain's seat, in which case the cushion airbag 30 is disposed between a seat spring (not shown) and the cushion pad 18. Furthermore, the mounting location of the cushion airbag 30 is not limited to the submarine reinforcement 28, but may also be a cross member (not shown) extending in the seat width direction of the vehicle seat 12. Furthermore, an exhaust valve 58 may be used together with the control valve 54 to adjust the internal pressure of the cushion airbag 30. [Explanation of symbols]

[0062] 10. Cushion airbag device 12 Vehicle seats 14 seat cushion 16 Base material 18 cushion pad 24 Side frame 28 Submarine reinforcement (construction member) 30 Cushion airbag 32 Base fabric 34 Intake passage 36 Air intake 50 High-pressure tank (accumulator tank) 52 First piping (piping) 54 Control valve 58 Exhaust valve 62 Second piping 64 Switching valve 80 Inflator C fold line

Claims

1. a cushion airbag provided under a seat cushion of a vehicle seat and inflated in a vertical direction by gas supplied from an accumulator tank; a control valve provided in a first pipe communicating the cushion airbag with the pressure accumulator tank, the control valve adjusting the internal pressure of the cushion airbag; an exhaust valve provided in the first pipe between the control valve and the cushion airbag, for exhausting the gas from inside the cushion airbag; a switching valve provided in a second pipe that connects the cushion airbag and the pressure accumulator tank, the switching valve being opened when the vehicle crashes; A cushion airbag device comprising:

2. a cushion airbag provided under a seat cushion of a vehicle seat and inflated in a vertical direction by gas supplied from an accumulator tank; a control valve provided in a pipe connecting the cushion airbag and the pressure accumulator tank, the control valve adjusting the internal pressure of the cushion airbag; an exhaust valve provided in the piping between the control valve and the cushion airbag, for exhausting the gas from inside the cushion airbag; an inflator that is activated when a vehicle crashes and supplies gas to the interior of the cushion airbag; A cushion airbag device comprising:

3. The switching valve is a partition wall capable of closing the second pipe, and a stopper supporting the partition wall, 2. The cushion airbag device according to claim 1, wherein the stopper is a mechanical valve that instantly releases support for the partition wall by the stopper when the vehicle crashes.

4. 3. The cushion airbag device according to claim 1, wherein the control valve is opened for a predetermined time when the vertical acceleration of the vehicle body exceeds a predetermined threshold value while the vehicle is running.

5. The cushion airbag is Two base fabrics are sewn along the outer periphery and folded in half along the fold lines, stacking them one on top of the other. An air intake path is provided along the fold line and an air intake port is provided at one end of the fold line, 3. The cushion airbag device according to claim 1, wherein the fold line is located on the front side of the seat and the cushion airbag device is fixed to a bridge member that is bridged between side frames that constitute the seat cushion.

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