Passenger-side airbag system

Abstract

To provide a passenger-side airbag system that can accurately protect the occupant with a fully inflated airbag, even when it is configured to be stored in the lower part of the instrument panel. [Solution] The airbag 20 has a lower inflation portion 21 that inflates so as to protrude rearward from a storage portion 15 located on the lower 1a side of the instrument panel 1, and an upper inflation portion 35 that communicates with the lower inflation portion via a communication hole 47 and inflates above the lower inflation portion. The lower inflation portion and the upper inflation portion are joined at the periphery of the communication hole. When the upper inflation portion is fully inflated, its front lower surface abuts against the instrument panel, its upper surface abuts against the front windshield 5, and its rear lower surface is supported by the lower inflation portion. The lower inflation portion has a rear region 21b that is thicker than the front region 21a when fully inflated, and the upper surface that supports the rear lower surface of the upper inflation portion is inclined upward relative to the horizontal when viewed from the left and right sides.

Description

Technical Field

[0004]

[0001] The present invention relates to a passenger seat airbag device capable of protecting a passenger sitting in the passenger seat.

Background Art

[0002] Conventionally, as a passenger seat airbag device, there has been a configuration in which an airbag is folded and stored in a storage portion disposed on the lower side of an instrument panel. In this conventional passenger seat airbag device, the airbag inflates by allowing inflation gas discharged from an inflator to flow into the inside thereof, protruding rearward from the storage portion and expanding upward and forward, and when inflation is completed, it is configured to be disposed so as to widely cover the front of a passenger sitting in the passenger seat vertically (see, for example, Patent Document 1). Specifically, in this conventional passenger seat airbag device, the airbag covers the rear surface side of the instrument panel when inflation is completed, and the upper end side is brought into contact with a front windshield disposed above the instrument panel, and is configured to protect the upper body of the passenger by the upper region at the time of inflation completion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the conventional passenger seat airbag device, although the inflated airbag is partitioned by a partitioning member in the internal region, it is configured as an integral bag shape from the upper end side to the lower end side. Therefore, it is difficult to stably support the upper region by the lower region at the time of inflation completion, and there is a possibility that the upper body of the passenger cannot be accurately protected by the upper region.

[0005] The present invention aims to solve the above-mentioned problems and to provide a passenger-side airbag system that can accurately protect the occupant with an inflated airbag, even when it is configured to be stored on the lower side of the instrument panel. [Means for solving the problem]

[0006] The passenger-side airbag system according to the present invention comprises a storage compartment located on the lower side of the instrument panel in a vehicle, an airbag that is folded and stored in the storage compartment, and an inflator that supplies inflation gas to the airbag. In a passenger-side airbag system configured to inflate by allowing inflation gas to flow into the interior, causing the airbag to protrude rearward from its storage location while simultaneously deploying forward and upward, The airbag is constructed by connecting the lower and upper inflatable sections, each being a separate bag-like structure, with a lower inflatable section that inflates to protrude rearward from the storage area and is connected to the inflatable section, and an upper inflatable section that inflates above the lower inflatable section and is connected to the lower inflatable section via a communication hole. The upper inflatable section is the part that protects the upper body of the occupant seated in the passenger seat. When fully inflated, its front lower surface contacts the instrument panel, and its upper surface contacts the front windshield located above the instrument panel. The rear lower surface area, which forms the periphery of the communication hole, is supported by the lower inflatable section. The lower expansion section is characterized in that the area at the rear end when expansion is complete is thicker than the area at the front end located on the storage side, and the upper surface supporting the rear lower surface of the upper expansion section is inclined upward with respect to the horizontal when viewed from the left and right sides when expansion is complete.

[0007] In the passenger-side airbag device of the present invention, the airbag is configured to have an upper inflation section and a lower inflation section, each being a separate bag-like structure connected by a communication hole. The upper inflation section inflates by allowing the inflation gas that has flowed into the lower inflation section to flow into its interior through the communication hole. The upper inflation section and the lower inflation section are connected by being joined at the periphery of the communication hole. In other words, in the passenger-side airbag device of the present invention, in the initial stages of airbag inflation, the lower inflation section first inflates by allowing the inflation gas discharged from the inflator to flow into its interior, causing it to protrude rearward from its storage location. Subsequently, the upper inflation section inflates by allowing the inflation gas to flow into its interior through the communication hole. When the upper expansion section expands, the lower expansion section has almost completed its expansion. In the lower expansion section, the upper surface (the area forming the periphery of the communication hole) is positioned at an upward and backward tilt relative to the horizontal when viewed from the left and right sides. As a result, the upper expansion section can be pushed by the upper surface (the area at the periphery of the communication hole) of the lower expansion section, causing it to expand and protrude forward and upward, allowing it to quickly come into contact with the front windshield and the upper surface of the instrument panel. Furthermore, even when the airbag has finished inflating, the lower inflation section, which supports the rear lower surface of the upper inflation section, has its upper surface in contact with the upper inflation section tilted upwards to the rear in the horizontal direction. This tilt of the upper surface of the lower inflation section causes a force to act on the fully inflated upper inflation section, tilting it downwards towards the front (pointing the front end downwards). As a result, the upper inflation section is pressed against the upper surface of the instrument panel over the front end region when it is fully inflated. Therefore, the front lower surface of the upper inflation section can be stably in contact with the upper surface of the instrument panel over its entire front-to-rear area.

[0008] Furthermore, in the passenger-side airbag device of the present invention, the lower inflatable section is made of a separate bag from the upper inflatable section, so that when inflation is complete, the areas around the periphery of the communication hole can come into contact with each other, thereby supporting the upper inflatable section. In addition, since the rear end area of ​​the lower inflatable section is thicker than the front end area when inflation is complete, this thicker rear end area can stably support the rear lower surface of the upper inflatable section, and it is also possible to suppress the movement of the upper inflatable section so that it collapses downward and rearward before the occupant is caught.

[0009] In other words, even if the passenger-side airbag device of the present invention is configured to store the airbag in the lower part of the instrument panel and inflate so that it protrudes rearward while expanding forward and upward, the upper inflation portion of the airbag can be rapidly inflated so that it comes into contact with the upper surface of the instrument panel and the front windshield. Furthermore, the contact state with the upper surface of the instrument panel can be stably maintained when the inflation of the upper inflation portion is complete, and the movement of the upper inflation portion such that it collapses downward and rearward after inflation is complete can also be suppressed. As a result, the upper body of the occupant can be stably protected by the upper inflation portion supported by the upper surface of the instrument panel, the front windshield and the lower inflation portion.

[0010] Therefore, even if the passenger-side airbag device of the present invention is configured to be stored on the lower side of the instrument panel, the occupant can be accurately protected by the fully inflated airbag.

[0011] Furthermore, the passenger-side airbag device of the present invention is configured to include an upper wall panel, which is arranged as a pair on the left and right sides, so that it faces the other side when inflation is complete. The lower expansion section is configured to include a pair of lower wall panels, one on the left and one on the right, which are positioned to face each other in the left-right direction when the expansion is complete. In the lower wall panel when laid flat, it is preferable to set the separation distance from the point on which the center of the communication hole is projected to the trailing edge to be greater than the separation distance from the point on which the center of the communication hole is projected to the trailing edge in the upper wall panel when laid flat.

[0012] If the passenger-side airbag system is configured as described above, the lower inflation section will have a wider front-to-back area located behind the communication hole when inflation is complete, and the rear lower surface of the upper inflation section will have a wider area extending towards the rear end that is located behind the communication hole when inflation is complete. In other words, the lower inflation section can widely support the rear lower surface area of ​​the upper inflation section towards the rear end. Therefore, the behavior of the upper inflation section tilting downwards and backwards before occupant detection can be suppressed more effectively.

[0013] Furthermore, in the passenger-side airbag device with the above configuration, a flow-rectifying cloth is provided inside the upper inflation section, covering the area around the communication hole and capable of rectifying the flow of inflation gas that flows into the interior through the communication hole. It is preferable to have a rectifying cloth in a roughly cylindrical shape that covers the area above the communication hole while leaving openings on both the left and right ends, and to have a gas outlet hole on the front side through which expansion gas can be discharged.

[0014] If the passenger-side airbag system is configured as described above, the inflation gas flowing into the upper inflation section can be prevented from flowing towards the rear and instead directed towards the front and upward. This allows the upper inflation section to inflate more quickly, protruding forward and upward, thus accelerating the start of contact with the upper surface of the front windshield and instrument panel. Furthermore, since the rectifying cloth prevents the inflation gas flowing into the upper inflation section from flowing towards the rear, it is also possible to prevent the upper inflation section from inflating to protrude significantly towards the rear, towards the occupant. As a result, the upper inflation section can be inflated quickly and effectively to protect the occupant by suppressing forward and backward swaying during deployment. [Brief explanation of the drawing]

[0015] [Figure 1] It is a schematic longitudinal sectional view of a vehicle-mounted passenger seat airbag device according to an embodiment of the present invention. [Figure 2] It is a schematic enlarged longitudinal sectional view of the passenger seat airbag device according to the embodiment. [Figure 3] It is a schematic perspective view showing a state where the airbag used in the passenger seat airbag device according to the embodiment is inflated alone. [Figure 4] It is a left side view of the airbag in FIG. 3. [Figure 5] It is a plan view of the airbag in FIG. 3 seen from above. [Figure 6] It is a rear view of the airbag in FIG. 3 seen from behind. [Figure 7] It is a schematic longitudinal sectional view along the front-back direction of the airbag in FIG. 3. [Figure 8] It is a schematic partial longitudinal sectional view along the left-right direction showing the position of the communication hole in the airbag of FIG. 3. [Figure 9] It is a schematic partial cross-sectional view showing the position of the communication hole in the airbag of FIG. 3. [Figure 10] It is a plan view of the airbag in FIG. 3 in a state where the base materials constituting the upper inflation part are arranged side by side. [Figure 11] It is a plan view of the airbag in FIG. 3 in a state where the base materials constituting the lower inflation part, the base materials constituting the rectifying cloth, and the base materials constituting the tether are arranged side by side. [Figure 12] It is a plan view of the airbag in FIG. 3 in a state where the upper side wall panel on the left side and the lower side wall panel on the left side are arranged side by side. [Figure 13] It is a schematic longitudinal sectional view showing the inflation process of the airbag in the passenger seat airbag device according to the embodiment. [Figure 14] It is a schematic longitudinal sectional view showing the inflation process of the airbag in the passenger seat airbag device according to the embodiment, showing the process after FIG. 13. [Figure 15]This is a schematic longitudinal cross-sectional view showing the completed inflation state of the passenger-side airbag device according to the embodiment. [Figure 16] Figure 15 is a partially enlarged cross-sectional view showing the region of the lower expansion. [Modes for carrying out the invention]

[0016] Hereinafter, one embodiment of the present invention will be described with reference to the drawings. The passenger-side airbag device (hereinafter abbreviated as "airbag device") M of the embodiment is disposed on the rear surface 3 side of the lower part 1a side of the instrument panel (hereinafter abbreviated as "instrument panel") 1, as shown in Figures 1 and 2. In this embodiment, unless otherwise specified, the front-rear, up-down, and left-right directions correspond to the front-rear, up-down, and left-right directions of the vehicle.

[0017] As shown in Figures 1 and 2, the airbag device M comprises a case 16 as a storage area located on the lower 1a side of the instrument panel 1, an airbag 20 that is folded and stored in the case 16, an inflator 12 that supplies inflation gas to the airbag 20, a retainer 13 for attaching the airbag 20 and the inflator 12 to the case 16, and an airbag cover 10 that covers the folded airbag 20.

[0018] The airbag cover 10 is formed to be connected to the instrument panel 1, is made of synthetic resin, and has a single door portion 10a that opens when the airbag 20 is deployed and inflated. In this embodiment, the door portion 10a is configured to open downward when pushed by the airbag 20. In addition, a connecting wall portion 10b that is connected to the case 16 is formed around the door portion 10a of the airbag cover 10 so as to protrude forward.

[0019] As shown in Figure 2, the inflator 12 comprises a substantially cylindrical main body portion 12a having a plurality of gas discharge ports 12b, and a flange portion 12c for attaching the inflator 12 to the case 16. In the airbag device M of this embodiment, the inflator 12 is attached to the front end side (bottom wall portion 16a) of the case 16 such that the axial direction of the main body portion 12a is aligned with the front-rear direction.

[0020] The case 16, which serves as the storage area, is formed in a substantially rectangular parallelepiped shape with a rectangular opening at its rear end. As shown in Figure 2, it comprises a substantially rectangular bottom wall portion 16a into which the inflator 12 is inserted and mounted from the front, and a peripheral wall portion 16b that extends rearward from the outer edge of the bottom wall portion 16a and engages with the connecting wall portion 10b of the airbag cover 10. The case 16 is located on the lower 1a side of the instrument panel 1 (a position separated from the upper surface 2 of the instrument panel 1), specifically, in a position above and in front of the knees of the occupant MP seated in the passenger seat, with its axial direction aligned with the front-rear direction (horizontal direction) (see Figure 1). The opening provided at the rear end of the case 16 constitutes a protruding opening 17 into which the airbag 20, which inflates by allowing inflation gas to flow into it, can be projected towards the rear. In this embodiment, the airbag 20 and the inflator 12 are attached to the bottom wall 16a of the case 16 by using the bolts 13a of the retainer 13 disposed inside the airbag 20 as mounting means, passing through the periphery of the intake opening 26 in the airbag 20 (described later), the bottom wall 16a of the case 16, and the flange portion 12c of the inflator 12, and securing them with nuts 14. This case 16 is connected to the vehicle body using a bracket (not shown).

[0021] The airbag 20 is formed from a flexible sheet and comprises an upper inflation section 35 and a lower inflation section 21, which are separate bag-shaped parts, as shown in Figures 3 to 7. The upper inflation section 35 and the lower inflation section 21 are connected to each other via a communication hole 47 and joined at the periphery of the communication hole 47 (see Figures 7 to 9). In addition, in the airbag 20 of this embodiment, a tether 52 that restricts the completed inflation shape of the upper inflation section 35 and a rectifying cloth 60 that can rectify the inflation gas G flowing into the upper inflation section 35 are disposed inside the upper inflation section 35 (see Figures 5, 7, and 10).

[0022] The lower expansion section 21 is a part that is connected to the inflator 12 and expands to protrude rearward from the case 16. As shown in Figures 3 to 6, the lower expansion section 21 has a roughly rectangular plate shape when fully expanded. The lower expansion section 21 comprises a left wall section 23 and a right wall section 24 that are arranged to face each other in the left-right direction when fully expanded, and a peripheral wall section 22 that connects the left wall section 23 and the right wall section 24 to form a region extending from front to back and up to down when fully expanded. At a position approximately in the left-right center on the front end of the peripheral wall section 22, an inlet opening 26 is formed, which is roughly circular in shape and allows expansion gas to flow into the interior, with its periphery attached to the bottom wall section 16a of the case 16 (see Figures 5 and 7). Multiple mounting holes 27 (four in this embodiment) are formed around the periphery of the inlet opening 26 for attaching the periphery of the inlet opening 26 to the bottom wall portion 16a of the case 16 by inserting the bolts 13a of the retainer 13 (see Figures 5 and 11). In the peripheral wall portion 22, an opening 28 constituting a communication hole 47 is formed at a position slightly behind the center of the front-to-back of the upper portion that constitutes the upper surface side of the lower expansion portion 21 (the rear upper portion 22b, which is the upper surface side of the rear region 21b described later) (see Figure 8). In this embodiment, the opening 28 is circular and two are arranged side by side on the left-to-right side (see Figures 5, 9, and 11).

[0023] Furthermore, the lower inflation section 21 includes a front region 21a that is positioned inside the case 16 when inflation is complete, and a rear region 21b that is positioned behind the front region 21a and below the upper inflation section 35 when inflation is complete (see Figures 7 and 16). The aforementioned inlet opening 26 and mounting hole 27 are located on the front end side of the front region 21a, and the opening 28 that constitutes the communication hole 47 is located on the upper surface side of the rear region 21b (see Figure 7). In the airbag 20 of this embodiment, the lower inflation section 21 is configured such that, when viewed from the left and right sides in the fully inflated state when mounted on a vehicle, the front region 21a is positioned along the front-rear direction (horizontal direction), and the rear region 21b is positioned so as to be tilted upwards with respect to the front-rear direction (horizontal direction), as shown in Figures 15 and 16. In the front region 21a, when the expansion is complete while the unit is inflated on its own, the width dimension (width dimension in the left-right direction) is kept approximately constant throughout the entire front-to-rear area, and the thickness dimension is also kept approximately constant throughout the entire front-to-rear area (see Figures 4, 5, and 7). In the rear region 21b, the thickness dimension when the expansion is complete is set to be larger than that of the front region 21a when the expansion is complete (see Figures 4 and 7). Furthermore, the upper surface of this rear region 21b when the expansion is complete (the rear upper part 22b, which is the area in the peripheral wall 22 where the opening 28 constituting the communication hole 47 is located) is also tilted upwards relative to the horizontal direction when viewed from the left and right sides in the expanded state when mounted on a vehicle (see Figures 15 and 16). The difference in thickness between the front region 21a and the rear region 21b, and the inclination of the rear region 21b, are due to the external shape of the pair of left and right lower wall panels 86L and 86R (see Figures 11 and 12), which will be described in detail later, and which constitute the left wall portion 23 and the right wall portion 24 in the lower expansion portion 21. The rear upper portion 22b, which constitutes the upper surface of the rear region, is arranged to be tilted upward relative to the horizontal when the airbag 20 is viewed from the left and right sides in the vehicle-mounted state after the airbag 20 has finished inflating (see Figures 15 and 16). Furthermore, the rear region 21b is configured to support the rear lower end of the upper inflation section 35 when the airbag 20 has finished inflating, and the width dimension of the upper surface (rear upper section 22b) in the left-right direction is matched with the width dimension of the rear lower surface (rear portion 39b of the lower wall section 39, described later) of the upper inflation section 35 (see Figures 6 and 8).Furthermore, as shown in Figure 5, the rear region 21b is configured such that when the airbag 20 is fully inflated, its rear end 21ba is positioned to substantially coincide with the rear end 35ba of the upper inflation section 35. Moreover, the rear region 21b has a substantially trapezoidal shape, which narrows downwards when viewed from the rear after inflation (see Figures 6 and 8). In the airbag 20 of this embodiment, the upper inflation section 35 is also configured to narrow downwards when viewed from the rear after inflation, and the rear region 21b is configured such that the left and right edges of the fully inflated shape when viewed from the rear are connected to the outline of the upper inflation section 35 (see Figure 6).

[0024] The upper inflatable section 35 is a bag-like structure connected to the lower inflatable section 21 via a communication hole 47, and is a part that protects the upper body MU of the occupant MP seated in the passenger seat. When fully inflated, it is positioned to close the space between the upper surface 2 of the instrument panel 1 and the front windshield 5 located above the instrument panel 1, and its rear lower side is supported by the lower inflatable section 21 (see Figure 15). As shown in Figures 3 to 7, the upper inflatable section 35 comprises a front wall section 36 and a rear wall section 37 that face each other in the front-rear direction when fully inflated, an upper wall section 38 and a lower wall section 39 that face each other in the up-down direction when fully inflated, and a left wall section 40 and a right wall section 41 that face each other in the left-right direction when fully inflated. Furthermore, in the airbag 20 of this embodiment, the upper inflation section 35 is configured such that the rear region 35b (the region on the rear wall 37 side) that is positioned on the occupant MP side when the airbag 20 is fully inflated is wide from side to side to accurately protect the upper body MU of the occupant MP, while the front region 35a that is positioned on the front side is narrow from side to side (see Figure 5). The width dimension of the front region 35a in the left-right direction when inflation is fully inflated is set to be about 1 / 3 of the width dimension of the widest region (the upper end side of the rear wall 37) in the left-right direction in the rear region 35b. As shown in Figure 5, the width dimension of this front region 35a in the left-right direction when inflation is fully inflated is set to be smaller than the width dimension of the front region 21a in the lower inflation section 21.

[0025] In the upper inflatable section 35, the rear wall section 37 is positioned to substantially follow the vertical direction in front of the upper body MU of the occupant MP seated in the passenger seat when the airbag 20 has finished inflating, and is the part that receives and protects the upper body MU of the occupant MP as it moves forward. The width dimensions of the rear wall section 37 are set to dimensions that can receive and protect the upper body MU of the occupant MP. Specifically, the outer shape of the rear wall section 37 when viewed from the rear is a substantially inverted trapezoid shape, with the upper part being wider from left to right and narrowing towards the lower end (see Figure 6). The upper wall section 38 is positioned at a downward slope when the airbag 20 has finished inflating, and is the part that comes into contact with the front windshield 5. The front part 39a of the lower wall section 39 is the part that comes into contact with the upper surface 2 of the instrument panel 1 when the airbag 20 has finished inflating (see Figures 15 and 16). The rear portion 39b of the lower wall portion 39 is positioned one level below the front portion 39a when the airbag 20 has finished inflating, and is positioned in contact with the rear upper portion 22b of the peripheral wall portion 22 of the lower inflation portion 21 (see Figures 7, 15, and 16). The front wall portion 36 is positioned substantially along the vertical direction so as to connect the front end of the upper wall portion 38 and the front end of the front portion 39a of the lower wall portion 39. In the airbag 20 of this embodiment, the front portion 39a of the lower wall portion 39 is configured to be narrow from the front portion 39a through the front wall portion 36 to the front portion of the upper wall portion 38, and the rear portion of the upper wall portion 38 is configured to gradually increase in width towards the rear wall portion 37. Furthermore, in the airbag 20 of this embodiment, the front wall portion 36 (the front end 35aa of the upper inflation portion 35 when inflation is complete) is configured to be located in front of the front end (inlet opening 26) of the lower inflation portion 21 (see Figure 7). That is, when the airbag 20 is fully inflated, the upper inflation portion 35 is configured to have its front end 35aa positioned in front of the case 16, as shown in Figure 15. The left wall portion 40 and the right wall portion 41 have vent holes 43, 43 that open in a substantially circular shape to exhaust excess inflation gas that has flowed into the upper inflation portion 35. Each vent hole 43 is located near the front upper edge of the left wall portion 40 and the right wall portion 41 (in front of the tether 52, which will be described later, and within the front region 35a of the upper inflation portion 35).

[0026] In the rear portion 39b of the lower wall portion 39 (the area on the lower surface side of the rear region 35b of the upper expansion portion 35, which is supported by the lower expansion portion 21 when inflation is complete), an opening 44 constituting a communication hole 47 is formed, corresponding to the opening 28 formed in the rear upper portion 22b of the peripheral wall portion 22 of the lower expansion portion 21 (see Figures 8 and 10). The opening 44 is circular and two are arranged side by side on the left-right side. In other words, in the airbag 20 of this embodiment, two communication holes 47 that connect the upper expansion portion 35 and the lower expansion portion 21 are arranged side by side on the left-right side. More specifically, when the airbag 20 is inflated, the communication holes 47 are formed at two locations symmetrically on the left and right sides of the airbag 20, centered on the left and right sides of the airbag 20 (see Figures 5, 8, and 9).

[0027] The upper expansion portion 35 and the lower expansion portion 21 are connected to each other by sewing the rear portion 39b of the lower wall portion 39 and the rear upper portion 22b of the peripheral wall portion 22 together using sutures at the periphery of the communication hole 47 (the periphery of each opening 28, 44). In this embodiment, the suture portion 48 connecting the upper expansion portion 35 and the lower expansion portion 21 (the rear portion 39b and the rear upper portion 22b) is formed in a double layer so as to surround the two communication holes 47, as shown in Figure 9. More specifically, in the suture portion 48, the inner portion 48a, which is positioned on the inside, is shaped like a wide oval on both sides so as to surround the two communication holes 47. The outer portion 48b, positioned on the outside, surrounds the inner portion 48a and is roughly rectangular in shape, such that the front region (the region in front of the communication hole 47) when inflation is complete is further away from the inner portion 48a than the rear region. More specifically, the width dimension of the outer portion 48b in the left-right direction is set to be slightly narrower than the width dimension in the left-right direction of the rear portion 39b of the lower wall portion 39 in the upper inflation portion 35 and the rear upper portion 22b of the peripheral wall portion 22 in the lower inflation portion 21 (see Figures 8-11). In other words, in the airbag 20 of this embodiment, the upper inflation portion 35 and the lower inflation portion 21 are connected to each other by joining the rear portion 39b of the lower wall portion 39 and the rear upper portion 22b of the peripheral wall portion 22, which constitute the periphery of the communication hole 47, by suture portions 48 over substantially the entire left and right sides. To put it another way, in the airbag 20 of this embodiment, the rear portion 39b of the lower wall portion 39 of the upper inflatable portion 35 and the rear upper portion 22b of the peripheral wall portion 22 of the lower inflatable portion 21 are sewn together and integrated at the front region that forms the periphery of the communication hole 47. When the airbag 20 is fully inflated during vehicle installation, the rear portion 39b and the rear upper portion 22b are positioned at an upward and backward angle relative to the horizontal direction (see Figure 16).

[0028] The tether 52, which is disposed within the upper expansion portion 35, is more specifically disposed within the rear region 35b of the upper expansion portion 35. In this embodiment, it has a left-right connecting portion 53 that connects the left wall portion 40 and the right wall portion 41, and a front-rear connecting portion 54 that connects the left-right connecting portion 53 and the rear wall portion 37. When viewed from the vertical direction, it is arranged in a flat, approximately Y-shape (see Figure 5). The left-right connecting portion 53 is a strip-shaped body formed from a flexible sheet material. Both ends are joined at a position slightly behind the front-rear center of the left wall portion 40 and the right wall portion 41, and near the vertical center, with the width direction substantially aligned with the vertical direction. When the expansion of the upper expansion portion 35 is complete, it is bent and positioned so that the left-right center is located towards the rear. In this embodiment, the left and right connecting portion 53 is composed of two tether base materials 56, 56 configured to be divided into two on the left and right sides (see Figure 11). The front and rear connecting portion 54 is positioned to connect the left and right centers of the left and right connecting portion 53 with the approximate center of the top, bottom, left, and right of the rear wall portion 37. It is a strip-shaped body formed from a flexible sheet material, with its width direction approximately aligned with the vertical direction, and is positioned approximately along the front and rear direction when the expansion of the upper expansion portion 35 is complete. In this embodiment, the front and rear connecting portion 54 is configured so that the rear end connected to the rear wall portion 37 is slightly wider than the front end connected to the left and right connecting portion 53 (see Figures 7 and 11). The tether 52 is positioned to restrict excessive outward protrusion of the left wall portion 40 and the right wall portion 41 in the upper inflation portion 35, and excessive rearward protrusion of the rear wall portion 37, when the airbag 20 is deployed and inflated. It also restricts the separation distance between the left wall portion 40 and the right wall portion 41 when inflation is complete, and restricts excessive rearward protrusion of the rear wall portion 37 (restricting the separation distance between the left and right connecting portions 53 and the rear wall portion 37).

[0029] The rectifying cloth 60, positioned within the upper expansion section 35, is arranged to cover the area around the communication hole 47 (specifically, above the communication hole 47) inside the upper expansion section 35 (see Figures 7 and 8). This rectifying cloth 60 is configured to rectify the expansion gas flowing into the interior through the communication hole 47. Specifically, it is configured to rectify the expansion gas G flowing in from the communication hole 47 so that it flows outwards to the left and right and forward. The rectifying cloth 60 is constructed to cover the area above the communication hole 47 by sewing its front edge 60a and rear edge 60b to the rear portion 39b of the lower wall 39 of the upper expansion section 35, respectively, in front of and behind the communication hole 47. It is configured to have gas outlet openings 62, 62 at the left end 60c and the right end 60d, respectively. Furthermore, in the rectifying cloth 60, a gas outlet hole 63 is provided in the front region 60e located at the front side, from which expansion gas can be discharged. In this embodiment, the gas outlet hole 63 is provided as a circular opening in the center of the front member 65, which will be described later, that constitutes the rectifying cloth 60 (see Figure 11). In this embodiment, the rectifying cloth 60 is composed of a front member 65 and a rear member 66 as shown in Figure 11. The front member 65 and the rear member 66 are set to have the same external shape, and the rectifying cloth 60 is constructed by sewing the upper edges 65a and 66a to each other and sewing the lower edges 65b and 66b to the rear portion 39b of the lower wall portion 39, respectively. The upper edges 65a and 66a of the front member 65 and the rear member 66 are curved in an arc shape so that the center protrudes upward. Furthermore, the rectifying cloth 60 of the embodiment has its front edge 60a and rear edge 60b (the lower edges 65b and 66b of the front member 65 and rear member 66) sewn together with the lower rear components 72A and 72B of the upper peripheral wall panel 70 (sewn together with the edges 70a and 70b), as described later, and is sewn to the rear portion 39b of the lower wall portion 39 (see Figure 7).

[0030] In the embodiment of the airbag 20, the separation distance D1 (see Figure 4) between the front end (intake opening 26) of the lower inflation section 21 and the front portion 39a of the lower wall section 39 of the upper inflation section 35, when viewed from the left and right sides in an inflated state, is set to be smaller than the separation distance D2 (see Figure 2) between the intake opening 26 (i.e., the front end of the case 16) and the front portion 39a of the lower wall section 39 of the upper inflation section 35 (i.e., the upper surface 2 of the instrument panel 1), when viewed from the left and right sides in a vehicle-mounted state of the airbag 20. The external shape of the airbag 20 when inflated on its own, as viewed from the left and right sides, will be described in detail later, but in this embodiment, it is mainly due to the external shape of the pair of left and right upper wall panels 76L and 76R that constitute the left wall portion 40 and the right wall portion 41 of the upper inflation portion 35, and the pair of left and right lower wall panels 86L and 86R that constitute the left wall portion 23 and the right wall portion 24 of the lower inflation portion 21.

[0031] In the airbag 20 of this embodiment, the upper inflation section 35 and the lower inflation section 21 are each constructed in a bag shape by joining the periphery edges of a base material (base fabric) of a predetermined shape. The upper inflation section 35 is composed of one upper peripheral wall panel 70 and a pair of left and right upper wall panels 76L and 76R, while the lower inflation section 21 is composed of one lower peripheral wall panel 80 and a pair of left and right lower wall panels 86L and 86R (see Figures 10 and 11).

[0032] The upper perimeter wall panel 70 constitutes the upper wall portion 38, rear wall portion 37, lower wall portion 39, and front wall portion 36 of the upper expansion portion 35. As shown in Figure 10, the upper perimeter wall panel 70 has an outer shape that is roughly symmetrical and roughly strip-shaped. Lower rear components 72A and 72B are arranged at both ends, which constitute the rear portion 39b of the lower wall portion 39 (the peripheral portion of the communication hole 47). Between these lower rear components 72A and 72B, a narrow portion 73 which constitutes the portion from the front portion 39a of the lower wall portion 39 through the front wall portion 36 to the front of the upper wall portion 38, and a wide portion 74 which constitutes the region from the rear of the upper wall portion 38 to the rear wall portion 37 are arranged in series.

[0033] The left and right upper wall panels 76L and 76R constitute the left wall portion 40 and the right wall portion 41 that face each other in the left-right direction when the expansion is complete in the upper expansion portion 35, and their external shapes are symmetrical (see Figure 10). At the outer edges 77L and 77R of the upper wall panels 76L and 76R, the lower front portion 77a that constitutes the left or right edge of the front portion 39a of the lower wall portion 39 and the lower rear portion 77b that constitutes the left or right edge of the rear portion 39b of the lower wall portion 39 are formed to be approximately parallel while having a step difference.

[0034] The upper expansion portion 35 is formed into a bag shape by overlapping the lower rear components 72A and 72B of the upper circumferential wall panel 70, sewing the front and rear edges 70a and 70b together, and sewing the left edge 70c and right edge 70d of the upper circumferential wall panel 70 to the outer edges 77L and 77R of the upper wall panels 76L and 76R, respectively (see Figures 7 and 8).

[0035] The lower peripheral wall panel 80 constitutes the peripheral wall portion 22 in the lower expansion portion 21, and as shown in Figure 11, its outer shape is a roughly symmetrical, roughly strip-like shape. The lower peripheral wall panel 80 has front end components 82A and 82B at both ends, which constitute the front end region of the peripheral wall portion 22 (the peripheral portion of the inflow opening 26). Between these front end components 82A and 82B, a rear upper surface component 83, which constitutes the rear upper portion 22b of the peripheral wall portion 22 (the peripheral portion of the communication hole 47), and a lower surface component 84, which constitutes the region from the rear end to the bottom of the peripheral wall portion 22, are arranged in series. The lower surface component 84 is configured to be narrow in the intermediate portions between the front and rear.

[0036] The left and right pair of lower wall panels 86L and 86R constitute the left wall portion 23 and the right wall portion 24 that face each other in the left-right direction when the expansion is complete in the lower expansion portion 21, and their external shapes are symmetrical (see Figure 11). At the outer peripheral edges 87L and 87R of the lower wall panels 86L and 86R, the front upper portion 87a, which constitutes the upper edge of the front region 21a (the left or right edge of the front upper portion 22a of the peripheral wall portion 22), and the rear upper portion 87b, which constitutes the upper edge of the rear region 21b (the left or right edge of the front and rear sides of the peripheral wall portion), are arranged to intersect at an obtuse angle. Furthermore, the front upper portion 87a is slightly inclined upwards towards the rear with respect to the front lower portion 87c, which constitutes the lower edge of the front region 21a. That is, the rear upper portion 87b of the outer peripheral edges 87L and 87R is inclined upwards towards the rear with respect to the front upper portion 87a. In the outer edges 87L and 87R of the lower wall panels 86L and 86R, the rear lower portion 87d, which constitutes the lower edge of the rear region 21b, is arranged to curve downwards relative to the rear upper portion 87b, which is formed in a substantially straight line. The separation distance D4 between the vicinity of the center of this rear lower portion 87d and the rear upper portion 87b is set to be larger than the separation distance D5 between the front upper portion 87a and the front lower portion 87c (see Figure 12).

[0037] The lower expansion portion 21 is formed into a bag shape by overlapping the front end components 82A and 82B of the lower peripheral wall panel 80, sewing the front and rear edges 80a and 80b together, and sewing the left edge 80c and right edge 80d of the lower peripheral wall panel 80 to the outer edges 87L and 87R of the lower wall panels 86L and 86R, respectively (see Figures 7 and 8).

[0038] The external shape of the airbag 20 when inflated on its own, as viewed from the left and right sides, is due to the external shapes of the pair of left and right upper wall panels 76L and 76R that constitute the left wall portion 40 and the right wall portion 41 of the upper inflation portion 35, and the pair of left and right lower wall panels 86L and 86R that constitute the left wall portion 23 and the right wall portion 24 of the lower inflation portion 21. As shown in Figure 12, when the upper wall panel 76L and the lower wall panel 86L are laid flat, the state in which the lower rear portion 77b of the outer peripheral edge 77L of the upper wall panel 76L and the rear upper portion 87b of the outer peripheral edge 87L of the lower wall panel 86L are overlapped approximates the external shape of the airbag 20 when inflated on its own, as viewed from the left and right sides (specifically, the left side). As shown in Figure 12, in the upper wall panel 76L and lower wall panel 86L, ​​when the lower rear portion 77b and the rear upper portion 87b are overlapped and laid flat, the separation distance D3 between the front end of the lower wall panel 86L and the lower front portion 77a on the outer peripheral edge 77L of the upper wall panel 76L is set to be smaller than the separation distance D2 between the front end (bottom wall portion 16a) of the case 16 and the upper surface 2 of the instrument panel 1 when the case 16 is mounted on the vehicle. In the lower wall panel 86L, ​​the separation distance D4 between the rear upper portion 87b and the rear lower portion 87d, which constitute the upper and lower edges of the rear region 21b, is set to be larger than the separation distance D5 between the front upper portion 87a and the front lower portion 87c, which constitute the upper and lower edges of the front region 21a, as described above. Furthermore, the separation distance D6 from point P1, which is the projection of the center of the communication hole 47 in the upper wall panel 76L when it is laid flat, to the trailing edge 76a is set to be smaller than the separation distance D7 from point P2, which is the projection of the center of the communication hole 47 in the lower wall panel 86L when it is laid flat, to the trailing edge 86a (see Figure 12).

[0039] In the embodiment, as shown in Figures 10 and 11, the upper perimeter wall panel 70, upper side wall panels 76L and 76R, lower perimeter wall panel 80, lower side wall panels 86L and 86R that constitute the airbag 20, the left and right connecting parts 53 (tether base materials 56, 56) and front and rear connecting parts 54 that constitute the tether 52, and the front side member 65 and rear side member 66 that constitute the rectifying cloth 60 are each formed from a flexible woven fabric made of polyester yarn, polyamide yarn, or the like.

[0040] In the airbag device M of this embodiment, after being installed in the vehicle, when inflation gas is discharged from the gas outlet 12b of the inflator 12, the airbag 20 inflates by allowing the inflation gas to flow into its interior, pushing open the door portion 10a of the airbag cover 10. The airbag 20 then protrudes from the case 16 through the protruding opening 17 of the case 16 formed by pushing open the door portion 10a of the airbag cover 10, and expands while protruding forward and upward, completing its inflation as shown by the dashed line in Figure 1 and in Figure 15.

[0041] In the airbag device M of this embodiment, the airbag 20 is configured to have an upper inflation section 35 and a lower inflation section 21, each being a separate bag-like structure connected via a communication hole 47. The upper inflation section 35 inflates by allowing the inflation gas G that has flowed into the lower inflation section 21 to flow into its interior through the communication hole 47. The upper inflation section 35 and the lower inflation section 21 are connected by being joined at the periphery of the communication hole 47. In other words, in the airbag device M of this embodiment, in the initial stages of inflation of the airbag 20, the lower inflation section 21 first inflates by allowing the inflation gas discharged from the inflator 12 to flow into its interior, causing it to protrude rearward from the case 16 which serves as the storage area. Subsequently, the upper inflation section 35 inflates by allowing the inflation gas to flow into its interior through the communication hole 47. When the upper expansion portion 35 expands, the lower expansion portion 21 has almost completed its expansion. In the lower expansion portion 21, the upper surface (rear upper portion 22b of the peripheral wall portion 22), which is the surface on the upper expansion portion 35 side (the region constituting the periphery of the communication hole 47), is positioned at an upward and backward tilt relative to the horizontal when viewed from the left and right sides. Therefore, the upper expansion portion 35 can be pushed by the upper surface of the lower expansion portion 21 (the region of the periphery of the communication hole 47, i.e., the rear upper portion 22b of the peripheral wall portion 22), causing it to expand and protrude forward and upward, allowing it to quickly come into contact with the front windshield 5 and the upper surface 2 of the instrument panel 1. To describe in detail the deployment behavior of the airbag 20 in this embodiment, in the initial stages of inflation, the lower inflation section 21 first inflates by allowing inflation gas to flow into it and protruding rearward from the protruding opening 17 of the case 16 (see Figure 13A). Subsequently, the upper inflation section 35 inflates by allowing inflation gas to flow into it through the communication hole 47. It is pushed forward and upward by the upper surface of the lower inflation section 21 (the rear upper part 22b of the peripheral wall 22), which is positioned to be inclined upward at the rear. Furthermore, the inflation gas G flows into the upper inflation section 35 in a direction that is forward and upward, rectified by the rectifying cloth 60. As a result, the upper inflation section 35 inflates while deploying towards the front of the vehicle, as shown in Figure 13B.Then, as shown in Figures 14A and B, the upper expansion portion 35 completes its expansion by filling the gap between the instrument panel 1 and the front windshield 5 after making contact with the upper surface 2 of the instrument panel 1 and the front windshield 5.

[0042] Furthermore, even after the airbag 20 has finished inflating, the lower inflation portion 21, which supports the rear lower surface side (rear portion 39b of the lower wall portion 39) of the upper inflation portion 35, has an upper surface (rear upper portion 22b of the peripheral wall portion 22) that is in contact with the upper inflation portion 35 that is tilted upwards to the rear with respect to the horizontal direction (see Figures 15 and 16). As a result of this tilt of the upper surface (rear upper portion 22b of the peripheral wall portion 22) of the lower inflation portion 21, a force acts on the fully inflated upper inflation portion 35 that causes the entire structure to tilt downwards to the front (pointing the front end downwards), causing the upper inflation portion 35 to be pressed against the upper surface 2 of the instrument panel 1, particularly in the area on the front end 35aa side when inflation is complete. Therefore, the front lower surface (front portion 39a of the lower wall portion 39) of the upper inflation portion 35 can be stably brought into contact with the upper surface 2 of the instrument panel 1 over its entire front-to-rear area. In particular, in the airbag device M of the embodiment, the separation distance D1 between the front end (inlet opening 26) of the lower inflation section 21 and the front portion 39a of the lower wall section 39 of the upper inflation section 35, when the airbag 20 is inflated on its own and viewed from the left and right sides, is set to be smaller than the separation distance D2 between the inlet opening 26 (i.e., the front end of the case 16) of the airbag 20 when it is mounted in a vehicle and viewed from the left and right sides, and the front portion 39a of the lower wall section 39 of the upper inflation section 35 (i.e., the upper surface 2 of the instrument panel 1). That is, in the airbag device M of the embodiment, when mounted in a vehicle, the airbag 20 inflates by widening the gap between the lower inflation section 21 and the upper inflation section 35, and the upper inflation section 35 completes inflation by strongly pressing its front lower surface (front portion 39a of the lower wall section 39) against the upper surface 2 of the instrument panel 1 (strong interference). Therefore, when the upper inflation portion 35 is fully inflated, it is possible to maintain stable contact with the upper surface 2 of the instrument panel 1. Furthermore, in the airbag 20 of this embodiment, since the front end 35aa of the upper inflation portion 35 is positioned further forward than the front end (inlet opening 26) of the lower inflation portion 21 when inflation is fully inflated, this strong interference state between the front lower surface of the upper inflation portion 35 and the upper surface 2 of the instrument panel 1 can be maintained even more stably.

[0043] Furthermore, in the airbag device M of this embodiment, the lower inflatable section 21 is made of a separate bag from the upper inflatable section 35. Therefore, when inflation is complete, the area around the periphery of the communication hole 47 (more specifically, the area on the outer circumference of the suture portion 48) can come into contact with each other, thereby supporting the upper inflatable section 35. Moreover, since the rear end area (rear region 21b) of the lower inflatable section 21 is thicker than the front end area (front region 21a), this thicker rear region 21b can stably support the rear lower surface (rear portion 39b of the lower wall portion 39) of the upper inflatable section 35. This also prevents the upper inflatable section 35 from moving downward and backward before the occupant is caught.

[0044] In other words, even if the airbag device M of the embodiment is configured to store the airbag 20 on the lower side 1a of the instrument panel 1 and inflate so as to protrude rearward and expand forward and upward, the upper inflatable portion 35 of the airbag 20 can be rapidly inflated so as to come into contact with the upper surface 2 of the instrument panel 1 and the front windshield 5. Furthermore, the contact state with the upper surface 2 of the instrument panel 1 can be stably maintained when the upper inflatable portion 35 has finished inflating, and the movement of the upper inflatable portion 35 such as to fall backward and downward after inflation is complete can also be suppressed. As a result, the upper inflatable portion 35, supported by the upper surface 2 of the instrument panel 1, the front windshield 5 and the lower inflatable portion 21, can stably protect the upper body MU of the occupant MP.

[0045] Therefore, even if the airbag device M of this embodiment is configured to be stored on the lower side 1a of the instrument panel 1, the occupant MP can be accurately protected by the inflated airbag 20.

[0046] Furthermore, in the airbag device M of this embodiment, the left wall portion 40 and the right wall portion 41 of the upper inflation portion 35 are composed of a pair of left and right upper wall panels 76L and 76R, and the left wall portion 23 and the right wall portion 24 of the lower inflation portion 21 are composed of a pair of left and right lower wall panels 86L and 86R. In the lower wall panels 86L and 86R when laid flat, the separation distance D7 from point P2, which is the projection of the center of the communication hole 47, to the trailing edge 86a is set to be greater than the separation distance D6 from point P1, which is the projection of the center of the communication hole 47, to the trailing edge 76a of the upper wall panels 76L and 76R when laid flat. In other words, in the airbag device M of this embodiment, the lower inflation section 21 widens the area located behind the communication hole 47 when inflation is complete, and broadly covers the area located behind the communication hole 47 on the rear lower surface side of the upper inflation section 35 towards the rear end when inflation is complete. In other words, the lower inflation section 21 can broadly support the rear lower surface area of ​​the upper inflation section 35 (the rear portion 39b of the lower wall section 39) towards the rear end 39ba. That is, even if the area on the rear end 39ba side of the rear portion 39b moves downward, it can be stably supported by the area on the rear end 22ba side of the rear upper portion 22b of the peripheral wall section 22 (see the dashed line in Figure 16), thus more effectively suppressing the behavior of the upper inflation section 35 moving in a way that causes it to collapse downward and rearward before the occupant is caught. If these points are not taken into consideration, the lower wall panel may be configured such that the separation distance from the point where the center of the communication hole is projected to its rear end is equal to, or smaller than, the separation distance from the point where the center of the communication hole is projected to its rear end in the upper wall panel.

[0047] Furthermore, in the airbag device M of this embodiment, a rectifying cloth 60 is provided inside the upper inflation section 35, covering the area around the communication hole 47 and capable of rectifying the inflation gas flowing into the interior through the communication hole 47. The rectifying cloth 60 is roughly cylindrical in shape, covering the area above the communication hole 47 while having openings on both the left and right ends, and is equipped with a gas outlet hole 63 on the front side from which the inflation gas can be discharged. As a result, the inflation gas flowing into the upper inflation section 35 through the communication hole 47 is prevented from flowing to the rear and is instead directed to flow upward and forward. This allows the upper inflation section 35 to inflate more quickly, protruding upward and forward, thus accelerating the start of contact with the front windshield 5 and the upper surface 2 of the instrument panel 1. In addition, since the rectifying cloth 60 prevents the inflation gas G flowing into the upper inflation section 35 from flowing to the rear, it is also possible to prevent the upper inflation section 35 from inflating to protrude significantly towards the rear, which is the occupant MP side. Therefore, the upper expansion section 35 can be quickly inflated to protect the crew MP by suppressing forward and backward swinging during deployment. If this point is not considered, the upper expansion section may be configured without a rectifying cloth. [Explanation of symbols]

[0048] 1...Instrument panel (dashboard), 1a...Lower part, 2...Top surface, 5...Front windshield, 10...Airbag cover, 12...Inflator, 16...Case (storage area), 20...Airbag, 21...Lower inflation part, 21a...Front area, 21b...Rear area, 22...Peripheral wall, 22a...Upper front part, 22b...Rear upper part, 23...Left wall, 2 4...Right wall part, 26...Inflow opening, 35...Upper expansion part, 37...Rear wall part, 39...Lower wall part, 39a...Front side part, 39b...Rear part, 40...Left wall part, 41...Right wall part, 47...Communication Hole, 60... rectifier cloth, 63... gas outflow hole, 76L, 76R... upper wall panel, 76a... trailing edge, 86L, ​​86R... lower wall panel, 86a... trailing edge, M... airbag device for passenger seat.

Claims

1. The system comprises a storage compartment located on the lower side of the instrument panel in a vehicle, an airbag that is folded and stored in the storage compartment, and an inflator that supplies inflation gas to the airbag. In a passenger-side airbag system configured such that the airbag inflates by allowing the inflation gas to flow inside, protruding rearward from the storage area while deploying forward and upward, The airbag is configured such that each airbag is a separate bag-like structure, comprising a lower inflation section that is connected to the inflator and inflates to protrude rearward from the storage area, and an upper inflation section that is connected to the lower inflation section via a communication hole and inflates above the lower inflation section, and the lower inflation section and the upper inflation section are connected by joining them at the periphery of the communication hole. The upper inflatable portion is a part that protects the upper body of the occupant seated in the passenger seat. When inflation is complete, the front lower surface abuts against the instrument panel, and the upper surface abuts against the front windshield located above the instrument panel, with the rear lower surface area forming the periphery of the communication hole being supported by the lower inflatable portion. A passenger-side airbag device characterized in that the lower inflatable portion is configured such that the area at the rear end when inflation is complete is thicker than the area at the front end located on the storage side, and the upper surface supporting the rear lower surface of the upper inflatable portion is inclined upward with respect to the rear in the horizontal direction when viewed from the left and right sides when inflation is complete.

2. The upper expansion section comprises upper wall panels arranged as a pair, left and right, so as to face each other in the left-right direction when the expansion is complete. The aforementioned lower expansion section comprises a pair of lower wall panels, one on the left and one on the right, which are arranged to face each other in the left-right direction when the expansion is complete. The passenger-side airbag device according to claim 1, characterized in that, when the lower wall panel is laid flat, the separation distance from the point on which the center of the communication hole is projected to the trailing edge is set to be greater than the separation distance from the point on which the center of the communication hole is projected to the trailing edge of the upper wall panel when laid flat.

3. A flow-straightening cloth is provided inside the upper expansion section, covering the area around the communication hole and capable of rectifying the expansion gas flowing into the interior through the communication hole. The passenger-side airbag device according to claim 1 or 2, characterized in that the rectifying cloth is in a substantially cylindrical shape that covers the upper part of the communication hole while leaving open sides on both the left and right, and a gas outlet hole from which the expansion gas can be discharged is provided on the front side.

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