Passenger seat airbag device for vehicle

Abstract

To provide a vehicular airbag device for a front passenger seat that can suppress expansion behavior of an airbag main body from becoming unstable, even if the airbag main body for a front passenger seat having an upper chamber and a lower chamber is enlarged in size, accompanying thinning of an instrument panel.SOLUTION: A vehicular airbag device 20 for a front passenger seat comprises: an airbag main body 30 partitioned into a lower chamber 32, stored at a lower part side of an instrument panel 14 positioned in front of knees and shins of an occupant P seated on a front passenger seat 12 of a vehicle 10, which restrains lower legs of the occupant P and an upper chamber 38 that restrains an upper body of the occupant P; and a rectification cylinder 40, provided inside the airbag main body 30, through which gas jetted from an inflator 24 is distributed to the lower chamber 32 and the upper chamber 38. The rectification cylinder 40 is formed to have a curve shape along an outer shape pf a rear surface 14A of the instrument panel 14 when the cylinder is inflated and expanded by jetted gas.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a passenger seat airbag device for a vehicle. [Background technology]

[0002] A structure in which a passenger airbag device with an integrated knee cushion and torso cushion is stored in the lower part of an instrument panel has been known for some time (see, for example, Patent Document 1). Also, a passenger airbag device in which a passenger airbag and an inflator are stored inside a lower cover of an instrument panel, and a cylindrical baffle that releases gas to the side and a knee cushion are provided inside the airbag have been known for some time (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 52-005127 [Patent Document 2] Japanese Patent Application Publication No. 08-072661 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, there has been a trend in design to make instrument panels thinner. However, in order to obtain the same level of lower limb restraint performance as before in the event of a frontal collision, a large knee airbag is required to fill the gap between the occupant and the lower surface of the instrument panel, which is now far from the occupant, and this causes problems in terms of increased manufacturing costs and weight. For this reason, a passenger airbag that integrates an airbag for the upper body, including the head (upper chamber) and a knee airbag (lower chamber) has been considered, and is simply constructed from a flat panel.

[0005] However, if the integrated three-dimensional airbag shape that restrains the upper body including the head and the lower limbs is constructed simply from a flat panel, the occupant restraint surface will tend to tilt backward, and the surface opposite the occupant restraint surface (the instrument panel side) will no longer come into contact with the windshield glass (no reaction force will be obtained from the windshield glass), making the deployment behavior of the passenger airbag unstable.

[0006] Therefore, an object of the present invention is to provide a passenger seat airbag device for a vehicle that can prevent the deployment behavior of the airbag body from becoming unstable, even if the passenger seat airbag body having an upper chamber and a lower chamber becomes larger as the instrument panel becomes thinner. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention No. 1 Aspects of The passenger seat airbag device for a vehicle is stored in the lower side of the instrument panel located in front of the knees and shins of an occupant seated in the passenger seat of the vehicle, and comprises an airbag body partitioned into a lower chamber for restraining the occupant's lower legs and an upper chamber for restraining the occupant's upper body, and a straightening tube provided inside the airbag body for distributing gas ejected from an inflator to the lower chamber and the upper chamber, the straightening tube being formed so as to form a curved shape that follows the outer shape of the rear surface of the instrument panel when it is inflated and deployed by the ejection of the gas.

[0008] No. 1 Aspects ofAccording to the invention, the straightening tube that distributes the gas ejected from the inflator to the lower and upper chambers of the airbag body is formed to have a curved shape that follows the outer shape of the rear surface of the instrument panel when the airbag body is inflated and deployed by the ejection of the gas. As a result, the instrument panel side of the inflated and deployed airbag body is disposed so as to follow the outer shape of the rear surface of the instrument panel and contacts the front windshield glass. Therefore, even if the passenger seat airbag body having the upper and lower chambers becomes larger due to the thinner instrument panel, the deployment behavior of the airbag body is prevented from becoming unstable.

[0009] The present invention also relates to No. 2 Aspects of The passenger seat airbag device for a vehicle is stored in the lower part of the instrument panel located in front of the knees and shins of an occupant seated in the passenger seat of the vehicle, and comprises an airbag body partitioned into a lower chamber that restrains the occupant's lower legs and an upper chamber that restrains the occupant's upper body, and a single inflator stored in the lower part of the instrument panel that supplies gas to the lower chamber and the upper chamber, the airbag body being composed of a first flat panel arranged on the instrument panel side and a second flat panel arranged on the occupant side, and the perimeter in the vertical direction of the first flat panel is set to be shorter than the perimeter in the vertical direction of the second flat panel.

[0010] No. 2 Aspects ofAccording to the invention, the airbag body is composed of a first flat panel arranged on the instrument panel side and a second flat panel arranged on the occupant side, and the circumferential length along the vertical direction of the first flat panel is set shorter than the circumferential length along the vertical direction of the second flat panel. As a result, the instrument panel side of the inflated and deployed airbag body is arranged to follow the outer shape of the rear surface of the instrument panel and contacts the front windshield glass. Therefore, even if the passenger seat airbag body having an upper chamber and a lower chamber is enlarged due to the thinning of the instrument panel, the deployment behavior of the airbag body is prevented from becoming unstable.

[0011] Also, The present invention relates to 3 Aspects of The passenger seat air bag device for a vehicle is No. 2 Aspects of The vehicle passenger seat airbag device further comprises a straightening tube provided inside the airbag body for distributing the gas ejected from the inflator to the lower chamber and the upper chamber.

[0012] No. 3 Aspects of According to the invention, a straightening tube that distributes the gas ejected from the inflator to the lower chamber and the upper chamber is provided inside the airbag body, and therefore the lower chamber is prevented from being ruptured by the high pressure of the gas, compared to a case in which the straightening tube is not provided.

[0013] Also, The present invention relates to 4 Aspects of The passenger seat air bag device for a vehicle is No. 3 Aspects of In a passenger seat airbag device for a vehicle, the airflow straightening cylinder is formed so as to assume a curved shape that follows the outer shape of the rear surface of the instrument panel when inflated and deployed by the ejection of gas.

[0014] No. 4 Aspects ofAccording to the invention, the straightening tube is formed to have a curved shape that conforms to the outer shape of the rear surface of the instrument panel when the airbag is inflated and deployed by the ejection of gas. Therefore, the instrument panel side of the inflated and deployed airbag body is more reliably positioned to conform to the outer shape of the rear surface of the instrument panel. Therefore, the deployment behavior of the airbag body is prevented from becoming unstable.

[0015] Also, The present invention relates to 5 Aspects of The passenger seat air bag device for a vehicle is No. 2~ No. Any 1 of 4 One aspect In the vehicle passenger seat airbag device, the first flat panel is tuck-sewn to set a circumferential length along the up-down direction to be short.

[0016] No. 5 Aspects of According to the invention, the first flat panel is tucked to set the perimeter in the up-down direction to be short, which reduces the manufacturing cost of the airbag body compared to when a first flat panel having a perimeter in the up-down direction previously set to be short is prepared. Effect of the Invention

[0017] As described above, according to the present invention, even if a passenger airbag having an upper chamber and a lower chamber becomes larger as a result of thinner instrument panels, it is possible to prevent the deployment behavior of the airbag from becoming unstable. [Brief description of the drawings]

[0018] [Figure 1] 1 is a schematic side view showing a passenger seat airbag device for a vehicle according to an embodiment of the present invention together with an occupant seated in the passenger seat. [Diagram 2] FIG. 2 is an enlarged schematic cross-sectional view taken along line XX in FIG. [Diagram 3] 1 is an enlarged schematic side view showing a passenger seat airbag device for a vehicle according to an embodiment of the present invention. [Figure 4] 1A is a front view showing a first flat panel constituting the airbag body of the vehicle passenger seat airbag device according to the present embodiment, and FIG. 1B is a front view showing a second flat panel constituting the airbag body of the vehicle passenger seat airbag device according to the present embodiment. [Diagram 5] 1A is a schematic side cross-sectional view showing, in enlargement, a part of the airbag body of the vehicle passenger seat airbag device according to the embodiment, and FIG. 1B is a schematic side cross-sectional view showing, in enlargement, a part of a modified example of the airbag body of the vehicle passenger seat airbag device according to the embodiment. [Figure 6] 2 is a schematic side view showing an enlarged view of the passenger seat airbag device for a vehicle according to the embodiment when the airbag body is inflated and deployed. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] 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 vehicle upward direction, the arrow FR indicates the vehicle forward direction, and the arrow RH indicates the vehicle rightward direction. Therefore, in the following explanation, unless otherwise specified, when the up / down, front / rear, and left / right directions are described, they refer to the up / down, front / rear, and left / right directions of the vehicle. In addition, the left / right direction is synonymous with the vehicle width direction.

[0020] 1, a vehicle passenger seat airbag device (hereinafter referred to as "airbag device") 20 according to this embodiment is provided, as an example, in a right-hand drive vehicle 10. That is, this airbag device 20 is stored in a lower part (inside a door part 16 described later) of a resin instrument panel (hereinafter referred to as "instrument panel") 14 located in front of the knees to the shins of an occupant P seated in a passenger seat 12, which is the left front seat of the vehicle 10.

[0021] The airbag device 20 includes a cloth airbag body 30 that is supported by a support member 22 provided on the lower side of the instrument panel 14 (inside the door portion 16) and stored in a folded state, and a single inflator 24 that is supported by the support member 22 and instantly ejects (supplies) gas into the airbag body 30. In Fig. 1, an occupant P seated in the passenger seat 12 is intentionally drawn separated from the airbag body 30 in order to show the shape of the inflated and deployed airbag body 30.

[0022] The inflator 24 is electrically connected to a detection device (not shown) such as an acceleration sensor provided on the vehicle 10, and is activated when a frontal collision of the vehicle 10 is detected by the detection device, thereby instantly ejecting gas. A door portion 16 is integrally formed on the lower side of the instrument panel 14, and is broken and opened by the airbag body 30 that inflates and deploys when the inflator 24 is activated, and FIG. 1 shows the door portion 16 in a broken state.

[0023] 1 to 3, the airbag body 30 is divided into a lower chamber 32 that restrains the lower legs of the occupant P and an upper chamber 38 that restrains the upper body including the head of the occupant P by a second tether 37 made of cloth, which will be described later. In other words, the airbag body 30 is configured by integrating an airbag for the upper body (upper chamber 38) and a knee airbag (lower chamber 32). The width (length along the left-right direction) of the airbag body 30 is set to a width that extends beyond both knees of the occupant P in the left-right direction (see FIG. 2).

[0024] The lower chamber 32 is further divided into upper and lower chambers by a first tether 35 made of cloth, which will be described later. That is, the lower chamber 32 is divided by the first tether 35 into a first lower chamber 34 on the lower side and a second lower chamber 36 on the upper side. The first lower chamber 34 functions as a knee airbag for a small occupant (not shown) (e.g., an occupant corresponding to the anthropomorphic dummy AF05), and the second lower chamber 36 functions as a knee airbag for a large occupant P (e.g., an occupant corresponding to the anthropomorphic dummy AM50).

[0025] In other words, the first lower chamber 34 below the first tether 35 faces the knees of a small occupant in the approximately front-rear direction, and the second lower chamber 36 between the first tether 35 and the second tether 37 faces the knees of a large occupant P in the approximately front-rear direction. Further, the lower chamber 32 does not have a vent hole through which gas is discharged after the lower legs of the occupant P are restrained, but the upper chamber 38 has vent holes (not shown) on both the left and right wall surfaces through which gas is discharged after the upper body of the occupant P is restrained.

[0026] Further, inside the airbag body 30, there is provided a cloth straightening cylinder 40 that distributes the gas ejected from the inflator 24 to the lower chamber 32 (first lower chamber 34 and second lower chamber 36) and the upper chamber 38. The straightening cylinder 40 is formed so as to have a substantially cylindrical shape when inflated and deployed by the ejection of gas (see FIG. 2), and is formed so as to have a curved shape that follows the outer shape of the rear surface 14A of the instrument panel 14 in a side view seen in the vehicle width direction.

[0027] 1 and 3, a circular opening 42A is formed in the center (axial center) of the lower end surface 42 of the flow straightening cylinder 40, and the opening 42A faces the inner surface of the front wall 34A of the first lower chamber 34. In other words, the gas ejected from the opening 42A is blown toward the inner surface of the front wall 34A of the first lower chamber 34.

[0028] A circular opening 44A is formed in a part of the wall surface (hereinafter referred to as the "rear surface 44") facing the rear side of the flow straightening cylinder 40, and the opening 44A faces the inner surface of the rear wall 36A of the second lower chamber 36. In other words, the gas ejected from the opening 44A is blown toward the inner surface of the rear wall 36A of the second lower chamber 36.

[0029] Furthermore, a circular opening 46A is formed in the center (axial center) of the upper end surface 46 of the straightening cylinder 40, and the opening 46A faces the inner surface of the front wall 38A (first flat panel 26 described below) of the upper chamber 38. In other words, the gas ejected from the opening 46A is blown toward the inner surface of the front wall 38A of the upper chamber 38.

[0030] As a result, a portion of the outer surface (the surface opposite the occupant restraint surface) of the front wall 38A of the upper chamber 38 comes into contact with the inner surface of the front windshield glass 18 with a predetermined pressure, and is pressed relatively rearward by the front windshield glass 18 (a reaction force is obtained from the front windshield glass 18) (see also Figure 6).

[0031] In this embodiment, as an example, the inner diameter of opening 46A on the upper end surface 46 of the straightening tube 40 is larger than the inner diameter of opening 44A on the rear surface 44 of the straightening tube 40, and the inner diameter of opening 44A on the rear surface 44 of the straightening tube 40 is larger than the inner diameter of opening 42A on the lower end surface 42 of the straightening tube 40.

[0032] However, the inner diameters of the openings 42A, 44A, 46A are not limited thereto, and it is sufficient that at least the inner diameter of the opening 46A in the upper end surface 46 is formed to be larger than the inner diameters of the opening 42A in the lower end surface 42 and the opening 44A in the rear surface 44. Therefore, for example, the inner diameter of the opening 42A in the lower end surface 42 and the inner diameter of the opening 44A in the rear surface 44 may be the same.

[0033] 4, the airbag body 30 is composed of a first flat panel 26 arranged on the instrument panel 14 side, and a second flat panel 28 arranged on the occupant P side. The first flat panel 26 and the second flat panel 28 have the same size and shape, and the airbag body 30 is manufactured by sewing together the outer peripheries of the first and second flat panels 26 and 28 (by flat sewing in which two pieces of base fabric are sewn together).

[0034] The vertical perimeter of the first flat panel 26 is set to be shorter than the vertical perimeter of the second flat panel 28 (in FIG. 4(A) the shorter perimeter is shown by an imaginary line). Specifically, the vertical perimeter of the first flat panel 26 is set (formed) to be shorter by tucking (picking) the first flat panel 26.

[0035] 4(A), a diamond-shaped sewing area SE, whose long sides are diagonal lines in the left-right direction, is set in the approximate vertical center of the first flat panel 26 in a front view seen from the front-rear direction of the vehicle 10. The sewing area SE is pinched and sewn from above and below, so that the perimeter of the first flat panel 26 in the vertical direction is shorter than the perimeter of the second flat panel 28 in the vertical direction.

[0036] As shown in Fig. 5, the tuck portion 26A, which is the portion where the sewing region SE is pinched and sewn, is not formed on the surface side (occupant restraint surface side) that comes into contact with the occupant P seated in the passenger seat 12, and therefore may protrude forward from the first flat panel 26 as shown in Fig. 5(A). Also, the tuck portion 26A may be folded into the airbag body 30 (upper chamber 38) so as not to protrude forward from the first flat panel 26 as shown in Fig. 5(B).

[0037] 2 and 3, the second tether 37 is configured to separate the lower chamber 32 (second lower chamber 36) and the upper chamber 38 of the airbag body 30, excluding the airflow straightening tube 40. That is, the outer peripheral edge of the second tether 37 is sewn to the inner surface of the airbag body 30 without any gaps. The inner diameter of an opening 37A, which is generally circular in plan view and formed in the second tether 37, to pass the airflow straightening tube 40 through is formed slightly smaller than the outer diameter of the inflated and deployed airflow straightening tube 40.

[0038] As a result, no gap is formed between the inner surface of the opening 37A of the second tether 37 and the outer surface of the inflated and deployed airflow straightening tube 40 (the inner surface of the opening 37A and the outer surface of the airflow straightening tube 40 are in close contact with each other), and even when the airflow straightening tube 40 is provided inside the airbag main body 30, the lower chamber 32 (second lower chamber 36) and the upper chamber 38 are each sealed.

[0039] The same is true for the first tether 35. That is, the first tether 35 is also configured to separate the first lower chamber 34 and the second lower chamber 36 of the lower chamber 32, except for the flow straightening tube 40. That is, the outer peripheral edge of the first tether 35 is sewn to the inner surface of the airbag main body 30 and attached without any gaps. And, in order to pass the flow straightening tube 40 through, the inner diameter of the opening 35A, which is substantially circular in plan view and formed in the first tether 35, is formed to be slightly smaller than the outer diameter of the inflated and deployed flow straightening tube 40.

[0040] This results in a configuration in which no gap is formed between the inner surface of the opening 35A of the first tether 35 and the outer surface of the inflated and deployed air straightening tube 40 (the inner surface of the opening 35A and the outer surface of the air straightening tube 40 are in close contact with each other), and even when the air straightening tube 40 is provided inside the airbag main body 30, the first lower chamber 34 and the second lower chamber 36 are each sealed.

[0041] Next, the operation of the airbag device 20 according to this embodiment configured as above will be described.

[0042] When the detection device detects a frontal collision of the vehicle 10, the inflator 24 is activated and instantly ejects (supplies) gas into the airbag body 30 through the inside of the airflow straightening tube 40. More specifically, as shown in FIG. 3, the gas ejected from the inflator 24 is first ejected (supplied) into the airflow straightening tube 40.

[0043] The gas ejected (supplied) into the flow straightening tube 40 is ejected from an opening 42A formed in the lower end surface 42 of the flow straightening tube 40 and supplied to the first lower chamber 34 of the lower chamber 32, and is also ejected from an opening 44A formed in the rear surface 44 of the flow straightening tube 40 and supplied to the second lower chamber 36 of the lower chamber 32.

[0044] Furthermore, the gas ejected (supplied) into the flow straightening cylinder 40 is ejected from an opening 46A formed in the upper end surface 46 of the flow straightening cylinder 40, and is supplied to the upper chamber 38. In other words, the gas ejected into the flow straightening cylinder 40 is distributed by the flow straightening cylinder 40 to the lower chamber 32 (the first lower chamber 34 and the second lower chamber 36) and the upper chamber 38.

[0045] Here, an opening 44A is formed in the rear surface 44 of the flow straightening tube 40. Therefore, compared to a flow straightening tube (not shown) in which only the opening 42A in the lower end surface 42 and the opening 46A in the upper end surface 46 are formed, it is possible to suppress the deployment behavior of the flow straightening tube 40 (particularly the portion disposed inside the upper chamber 38) from becoming unstable when gas is instantly ejected (supplied) and expanded and deployed.

[0046] Therefore, the inflated and deployed straightening tube 40 is quickly arranged in a curved shape that follows the outer shape of the rear surface 14A of the instrument panel 14 in a side view. Thus, the gas ejected from the opening 42A of the straightening tube 40 is blown onto the inner surface of the front wall 34A of the first lower chamber 34, and the gas ejected from the opening 44A of the straightening tube 40 is blown onto the inner surface of the rear wall 36A of the second lower chamber 36. And the gas ejected from the opening 46A of the straightening tube 40 is blown onto the inner surface of the front wall 38A of the upper chamber 38.

[0047] As a result, the entire airbag body 30 inflates and deploys so as to be pushed forward, and the instrument panel 14 side of the inflated and deployed airbag body 30 is disposed so as to follow the outer shape of the rear surface 14A of the instrument panel 14. In particular, a part of the outer surface of the front wall 38A of the upper chamber 38 comes into contact with the inner surface of the front windshield glass 18 with a predetermined pressure, and is pressed relatively rearward by the front windshield glass 18 (obtaining a reaction force from the front windshield glass 18).

[0048] Therefore, even if the airbag body 30 for the passenger seat 12 having the lower chamber 32 and the upper chamber 38 is enlarged due to the thinning of the instrument panel 14, it is possible to prevent the deployment behavior of the airbag body 30 from becoming unstable when gas is instantly supplied to the airbag body 30 to inflate and deploy (it is possible to stabilize the deployment behavior). Therefore, the lower limbs and upper body (including the head) of the occupant P seated in the passenger seat 12 can be appropriately restrained.

[0049] The airbag body 30 is composed of a first flat panel 26 arranged on the instrument panel 14 side and a second flat panel 28 arranged on the occupant P side. In other words, the airbag body 30 is manufactured by inexpensive flat sewing (by sewing two pieces of base fabric together). Therefore, the manufacturing cost and weight of the airbag body 30 can be reduced compared to an airbag body (not shown) in which the upper chamber and the lower chamber are integrated by three-dimensional sewing.

[0050] The circumferential length along the up-down direction of the first flat panel 26 is set to be shorter than the circumferential length along the up-down direction of the second flat panel 28. Therefore, compared to a case in which the circumferential length along the up-down direction of the first flat panel 26 and the circumferential length along the up-down direction of the second flat panel 28 are set to the same length, the instrument panel 14 side of the inflated and deployed airbag body 30 is positioned to more reliably follow the outer shape of the rear surface 14A of the instrument panel 14.

[0051] In other words, when the circumferential length along the up-down direction of the first flat panel 26 and the circumferential length along the up-down direction of the second flat panel 28 are set to be the same length, the upper chamber 38 of the inflated and deployed airbag body 30 tends to tilt backward as shown by the imaginary line in Fig. 6. In contrast, when the circumferential length along the up-down direction of the first flat panel 26 is set shorter than the circumferential length along the up-down direction of the second flat panel 28, the upper chamber 38 of the inflated and deployed airbag body 30 tends to tilt forward as shown by the solid line in Fig. 6 (the backward tilt is suppressed).

[0052] As a result, a portion of the outer surface of the front wall 38A of the upper chamber 38 more reliably comes into contact with the inner surface of the front windshield glass 18 with a predetermined pressure, and is pressed relatively rearward by the front windshield glass 18. Therefore, it is possible to further prevent the deployment behavior of the airbag body 30 from becoming unstable when gas is instantly supplied to the airbag body 30 to inflate and deploy (it is possible to further stabilize the deployment behavior), and it is possible to appropriately restrain the lower limbs and upper body (including the head) of the occupant P seated in the passenger seat 12.

[0053] Moreover, the first flat panel 26 is tuck-sewn so that its circumferential length in the up-down direction is set (formed) short. Therefore, the manufacturing cost of the airbag body 30 can be further reduced compared to the case where a first flat panel (not shown) is prepared in which the circumferential length in the up-down direction is set (formed) short in advance.

[0054] As described above, the gas ejected from the inflator 24 is distributed to the lower chamber 32 (the first lower chamber 34 and the second lower chamber 36) and the upper chamber 38 by the straightening cylinder 40 provided inside the airbag body 30. Therefore, compared to a case where the straightening cylinder 40 is not provided (where the ejected gas is not distributed to the upper chamber 38), it is possible to prevent the lower chamber 32 from being ruptured by the high pressure of the gas.

[0055] In addition, an opening 42A for ejecting gas into the first lower chamber 34 is formed in the center of the bottom end surface 42 of the flow straightening cylinder 40, and an opening 46A for ejecting gas into the upper chamber 38 is formed in the center of the top end surface 46 of the flow straightening cylinder 40. The inner diameter of the opening 46A is larger than the inner diameter of the opening 42A and the inner diameter of the opening 44A for ejecting gas into the second lower chamber 36.

[0056] Therefore, the amount of gas ejected into the upper chamber 38 and the amount of gas ejected into the lower chamber 32 (the first lower chamber 34 and the second lower chamber 36) can be appropriately controlled, and the lower chamber 32 (the first lower chamber 34 and the second lower chamber 36) can be further prevented from rupturing due to the high pressure of the gas that is instantly ejected.

[0057] Furthermore, by providing such a straightening cylinder 40, it is possible to easily adjust the internal pressure of the upper chamber 38 to be lower than the internal pressure of the lower chamber 32. In other words, in the airbag body 30, it is necessary to set the internal pressure of the upper chamber 38 lower than the internal pressure of the lower chamber 32, and the straightening cylinder 40 makes this possible easily.

[0058] Furthermore, in order to pass the flow straightening tube 40 through, the inner diameter of opening 35A formed in the first tether 35 and the inner diameter of opening 37A formed in the second tether 37 are each formed slightly smaller than the outer diameter of the expanded and deployed flow straightening tube 40, so that no gaps are formed between the inner surfaces of opening 35A of the first tether 35 and opening 37A of the second tether 37 and the outer surface of the expanded and deployed flow straightening tube 40.

[0059] In other words, the inner peripheral surfaces of the openings 35A and 37A are in close contact with the outer peripheral surface of the flow straightening cylinder 40, respectively, so that the lower chamber 32 (the first lower chamber 34 and the second lower chamber 36) and the upper chamber 38 are sealed. Therefore, the airtightness of the lower chamber 32 and the upper chamber 38 can be increased, and a high-pressure state in the lower chamber 32 and a low-pressure state in the upper chamber 38 can be easily created.

[0060] The passenger seat airbag device 20 for a vehicle according to this embodiment has been described above with reference to the drawings. However, the passenger seat airbag device 20 for a vehicle according to this embodiment is not limited to the illustrated one, and can be appropriately modified in design within the scope of the present invention. For example, the perimeter of the first flat panel 26 in the vertical direction is not limited to being shortened by tuck sewing, and may be set (formed) short in advance. In addition, the inflator 24 may be configured to be activated not only when a frontal collision of the vehicle 10 is detected, but also when a frontal collision of the vehicle 10 is predicted by a collision prediction sensor or the like. [Explanation of symbols]

[0061] 10 Vehicles 12 Passenger seat 14 Instrument panel 14A Rear 20 Airbag device (passenger seat airbag device for vehicles) 24 Inflator 26 First Flat Panel 28 Second Flat Panel 30 Airbag body 32 Lower Chamber 38 Upper Chamber 40 Rectifier tube P Crew

Claims

1. an airbag body that is stored in a lower portion of an instrument panel located in front of the knees and shins of an occupant seated in the passenger seat of a vehicle, the airbag body being partitioned by a second tether into a lower chamber for restraining the occupant's lower legs and an upper chamber for restraining the occupant's upper body, the lower chamber being partitioned vertically into a first lower chamber and a second lower chamber by a first tether; a straightening cylinder that is provided inside the airbag body so as to pass through the first tether and the second tether and distributes gas ejected from the inflator to the first lower chamber, the second lower chamber, and the upper chamber; Equipped with The air straightening tube is formed so as to form a curved shape that follows the outer shape of the rear surface of the instrument panel when inflated and deployed by the ejection of the gas, and is configured to blow the gas against the inner surface of the front wall of the first lower chamber, the inner surface of the rear wall of the second lower chamber, and the inner surface of the front wall of the upper chamber.

2. A passenger airbag device for a vehicle as described in Claim 1, wherein the air straightening tube is formed so that the inner diameter of the opening facing the inner surface of the front wall of the upper chamber is larger than the inner diameter of the opening facing the inner surface of the front wall of the first lower chamber and the inner diameter of the opening facing the inner surface of the rear wall of the second lower chamber.

3. 3. The vehicle passenger seat airbag device according to claim 1, wherein the airbag body is composed of a first flat panel arranged on the instrument panel side and a second flat panel arranged on the occupant side, and the perimeter of the first flat panel in the up-down direction is set to be shorter than the perimeter of the second flat panel in the up-down direction.

4. 4. The passenger seat airbag device for a vehicle according to claim 3, wherein the first flat panel is tuck-sewn so that a circumferential length in the up-down direction is set short.

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