Airbag system

Abstract

To provide an airbag system that can effectively protect occupants in a simple configuration. [Solution] The airbag device includes an airbag 20 configured to control its inflation state. The airbag comprises a bag body 21 and a control member 36 capable of controlling the inflation state of the bag body. The control member is connected to the bag body by sewing one end 36b to it using conductive thread T1, and the inflation state of the bag body is controlled by maintaining or releasing this connection to the bag body. The sewn portion 38 connecting one end of the control member to the bag body is made of conductive thread. The conductive thread is electrically connected to a control device, and when energized, it can release the connection between one end of the control member and the bag body by severing a predetermined part of the sewn portion.

Description

Technical Field

[0001] The present invention relates to an airbag device including an airbag configured to inflate with an inflation gas flowing therein to protect an occupant sitting on a seat and to control the inflated state.

Background Art

[0002] Conventionally, as an airbag device configured to control the inflated state of an airbag, there has been a configuration in which an exhaust hole portion is provided in a bag body that inflates to protect an occupant, and the opening and closing of the exhaust hole portion is controlled by an actuator provided separately (see, for example, Patent Document 1). Specifically, in a conventional airbag device, a small bag connected to an actuator is provided, and the exhaust hole portion is opened by inflating the small bag using the gas generated when the actuator operates.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in a conventional airbag device, since the inflated state of the airbag is controlled using an actuator and a small bag connected to the actuator, the configuration is not simple.

[0005] The present invention solves the above problems and aims to provide an airbag device with a simple configuration that can accurately protect an occupant.

Means for Solving the Problems

[0006] The airbag system according to the present invention comprises an airbag configured to inflate to protect an occupant seated in a vehicle seat by introducing an inflation gas into the interior, and to control the inflation state. The airbag comprises a bag body and a control member capable of controlling the inflation state of the bag body. The control member is connected to the bag body by sewing at least one end to it using conductive thread, and the expansion state of the bag body is controlled by maintaining or releasing the connection state of one end to the bag body using the conductive thread. The sewn portion connecting at least one end of the control member to the bag body is made of conductive thread, The conductive thread is electrically connected to the control device, and when power is applied, it is configured to detach a predetermined part of the sutured area, thereby releasing the connection between one end of the control member and the bag body.

[0007] In the airbag device of the present invention, a control member capable of controlling the inflation state of the bag body is configured to have at least one end connected to the bag body, and the inflation state of the bag body is controlled by maintaining or releasing this connection to the bag body. The control member is configured to have one end connected to the bag body by a suture, and this suture is made of conductive thread. The conductive thread is electrically connected to a control device, and when current is applied, a predetermined part of the suture is separated, thereby releasing this sutured state (connection state). In other words, in the airbag device of the present invention, if current is applied to the conductive thread constituting the suture that connects at least one end of the control member to the bag body at a predetermined time, the connection between one end of the control member and the bag body can be released, and the inflation state of the bag body can be changed by maintaining or releasing this connection between one end of the control member and the bag body. Therefore, unlike conventional airbag systems, the inflation state of the airbag (the bag itself) can be controlled without using a squib, thus simplifying the configuration. Furthermore, it is possible to reduce manufacturing costs, make the device lighter, and make the device itself more compact. Of course, in the airbag system of the present invention, since the inflation state of the airbag can be controlled, the occupant can be accurately protected by the fully inflated airbag.

[0008] Therefore, the airbag system of the present invention can effectively protect occupants with a simple configuration.

[0009] Furthermore, specifically, when the suture site is configured to include an upper thread and a lower thread, At least one of the upper or lower threads may be made of conductive thread. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram showing the area where an airbag device for the steering wheel, which is one embodiment of the present invention, is installed. [Figure 2]This is a schematic plan view of a steering wheel equipped with an airbag device according to an embodiment. [Figure 3] This is a schematic enlarged cross-sectional view of the airbag device of the embodiment in the front-rear direction. [Figure 4] This is a bottom view of the airbag used in the airbag device of the embodiment, in a flat, unfolded state. [Figure 5] Figure 4 is a longitudinal cross-sectional view of the airbag, showing the VV section of Figure 4. [Figure 6] Figure 4 is a partially enlarged bottom view showing the area of ​​the flap material in the airbag. [Figure 7] Figure 4 is a schematic, enlarged cross-sectional view showing the sutured area where the leading edge of the airbag flap material is sewn to the side wall of the vehicle body. [Figure 8] Figure 4 is a plan view showing the arrangement of the base materials that make up the airbag. [Figure 9] This is a schematic longitudinal cross-sectional view showing the state in which the airbag has completed inflation while the exhaust port remains closed by the flap material in the airbag device of the embodiment. [Figure 10] This is a partially enlarged cross-sectional view showing the inflated state of the airbag in the airbag device of the embodiment, with the flap material releasing the blockage of the exhaust port (the connection between the tip of the flap material and the vehicle body side wall being released). [Figure 11] This is a partially enlarged cross-sectional view showing the inflated state of the airbag in the airbag device of the embodiment, with the exhaust port closed by the flap material (the state in which the tip of the flap material is connected to the vehicle body side wall). [Modes for carrying out the invention]

[0011] Hereinafter, one embodiment of the present invention will be described with reference to the drawings. In this embodiment, the airbag device M will be described as one mounted on the steering wheel W as an example. Furthermore, in the airbag device M of this embodiment, as a control of the inflation state of the bag body 21, which will be described later in the airbag 20, a configuration that controls the internal pressure of the bag body 21 when inflation is complete will be described as an example. As shown in Figures 2 and 3, the steering wheel W comprises a steering wheel body 1 and an airbag device M positioned on the upper part of the central boss portion B of the steering wheel body 1. In this embodiment, the steering wheel body 1 comprises a ring portion R for gripping during steering, a boss portion B positioned approximately in the center of the ring portion R and connected to the steering shaft SS, and a plurality of spoke portions S (four in this embodiment) connecting the boss portion B and the ring portion R.

[0012] In this embodiment, unless otherwise specified, the front-rear, up-down, and left-right directions are based on the straight-line steering of the steering wheel W mounted on the vehicle. The up-down direction is defined as the vertical direction along the axial direction of the steering shaft SS (see Figure 2) to which the steering wheel W is assembled, the front-rear direction is defined as the front-rear direction of the vehicle which is perpendicular to the axis of the steering shaft SS, and the left-right direction is defined as the left-right direction of the vehicle which is perpendicular to the axis of the steering shaft SS.

[0013] As shown in Figures 2, 3, and 9, the steering wheel body 1 includes a core metal 2 made of a metal such as an aluminum alloy, which is arranged to connect the ring portion R, the boss portion B, and the spoke portion S; a synthetic resin coating layer 3 that covers the core metal 2 in the ring portion R and the spoke portion (not shown); and a synthetic resin lower cover 4 that covers the area below the boss portion B.

[0014] As shown in FIG. 3, the airbag device M includes an airbag 20, an inflater 9 that supplies inflation gas to the airbag 20, a case 11 as a storage part that stores and holds the folded airbag 20 and the inflater 9, an airbag cover 15 that covers the folded airbag 20, and a retainer 7 for attaching the airbag 20 and the inflater 9 to the case 11.

[0015] As shown in FIG. 3, the inflater 9 includes a substantially cylindrical main body portion 9a having a plurality of gas discharge ports 9b, and a flange portion 9c for attaching the inflater 9 to the case 11. A through hole (not shown) for passing a bolt (not shown) of the retainer 7 is formed in the flange portion 9c. The inflater 9 is electrically connected to a control device 60 described later.

[0016] The case 11 as a storage part is made of sheet metal and, as shown in FIG. 3, includes a substantially rectangular plate-shaped bottom wall part 12 into which the inflater 9 is inserted and attached from below, and a peripheral wall part 13 that extends vertically from the outer peripheral edge of the bottom wall part 12. At the upper end of the peripheral wall part 13, a mounting piece 13a that extends outward is formed (see FIG. 2). The airbag device M of the embodiment uses a mounting substrate of a horn switch mechanism (not shown) that is attached to the mounting piece 13a to attach and fix the case 11 to the core metal 2 of the steering wheel W, so that it is mounted on the upper part of the boss part B of the steering wheel main body 1 already attached to the steering shaft SS. Also, the side wall part 15c of the airbag cover 15 is attached to the peripheral wall part 13 of the case 11 using a rivet 16 or the like (see FIG. 3). In the case of the embodiment, the airbag 20 and the inflater 9 are attached to the bottom wall part 12 of the case 11 by using bolts (not shown) of a retainer 7 arranged in the airbag 20 as attachment means, passing these bolts through the peripheral edge of the inflow opening 24 in the airbag 20, the bottom wall part 12 of the case 11, and the flange part 9c of the inflater 9, and screwing them with nuts (not shown). Also, at a predetermined location in the case 11, although detailed illustration is omitted, insertion holes through which lead wires 45, 45 (described later) extending from the folded airbag 20 can be inserted are formed.

[0017] The airbag cover 15 is made of synthetic resin and includes a ceiling wall part 15a that covers the upper part of the airbag 20 housed in the case 11, and a substantially square tube-shaped side wall part 15c that extends downward from near the outer peripheral edge of the ceiling wall part 15a (see FIGS. 2 and 3). On the ceiling wall part 15a, two door parts 15b, 15b that are pushed by the expanding airbag 20 and open forward and backward are formed.

[0018] In the case of the embodiment, as shown in FIGS. 4 and 5, the airbag 20 includes a bag-shaped bag body 21, a tether 33 that regulates the inflated completed shape of the bag body 21, and a flap material 36 as a control member (internal pressure control member) that can control the inflated state of the bag body 21 (specifically, can control the internal pressure at the time of inflation completion).

[0019] The bag body 21 is configured such that, when fully inflated, it can cover almost the entire upper surface of the steering wheel W. The inflated shape is approximately circular when viewed from above and approximately ellipsoidal when viewed from the side, as shown by the dashed line in Figures 1 and 2 and in Figure 9. As shown in Figures 4 and 5, the bag body 21 comprises a driver side wall portion 31 positioned on the driver MD side and a vehicle body side wall portion 23 positioned on the steering wheel W (vehicle body) side. As shown in Figure 8, the bag is formed by joining (sewing with suture thread) the outer edges 50a and 51a of the approximately circular driver side panel 51 and vehicle body side panel 50, which have approximately the same outer shape, to each other. The driver side panel 51 and vehicle body side panel 50 that constitute the bag body 21 are formed from a flexible woven fabric made of polyamide yarn, polyester yarn, etc.

[0020] In the bag body 21, as shown in Figures 4 and 5, an inlet opening 24 is formed in a circular shape approximately in the center of the vehicle body side wall portion 23, allowing inflation gas to flow into the interior. This inlet opening 24 allows the main body portion 9a of the inflator 9 to be inserted from below, and four mounting holes 25 are formed around the periphery of the inlet opening 24 for inserting bolts (not shown) formed in the retainer 7. In addition, a vent hole 27 is formed in the vehicle body side wall portion 23 of the bag body 21 to exhaust excess inflation gas that has flowed into the interior. In this embodiment, the vent hole 27 is formed in a circular shape and is provided in two locations. Specifically, the vent hole 27 is provided in symmetrical positions with respect to a line CL (see Figure 4) that runs in the front-rear direction passing through the center of the inlet opening 24 as the reference line, and is positioned in an area inside the ring portion R when the airbag 20 has finished inflating (see the dashed line in Figure 2).

[0021] Furthermore, in the vehicle side wall portion 23 of the bag body 21, an exhaust hole 29 is formed, which is opened and closed by a flap material 36, separate from the vent hole 27 that is always open. The exhaust hole 29 is configured with an opening shape that is approximately circular, and in the embodiment, when the bag body 21 is laid flat, it is positioned between the vent holes 27, 27 and in front of the inlet opening 24 (specifically, with its center on line CL) (see Figures 4 and 6). In detail, the exhaust hole 29 and the vent holes 27, 27 located on both the left and right sides of the exhaust hole 29 are arranged in a substantially radial pattern with the inlet opening 24 as the center. More specifically, the exhaust port 29 is positioned at a distance from the inlet opening 24 that is approximately the same as the distance from the inlet opening 24 of each vent hole 27. Like the vent holes 27, the exhaust port 29 is positioned in a region that is inside the ring portion R when the bag body 21 is fully expanded (see the dashed line in Figure 2 and Figure 9). In other words, the exhaust port 29 is positioned in a region where the curvature of the cross-section is set to be small when the bag is fully expanded, resulting in a nearly planar shape. In addition, in this embodiment, the exhaust port 29 has a larger opening area than each vent hole 27, as shown in Figures 4 and 6. Specifically, in this embodiment, the inner diameter d1 of the exhaust port 29 is set to approximately 1.4 times the inner diameter d2 of each vent hole 27. In this embodiment, the periphery of both the exhaust port 29 and each vent hole 27 is reinforced by approximately annular reinforcing fabrics 57 and 58 (see Figures 4-6 and 8).

[0022] The tether 33, which regulates the completed inflation shape of the bag body 21, is positioned to connect the periphery of the inflow opening 24 in the vehicle body side wall portion 23 with the vicinity of the center of the driver's side wall portion 31, and regulates the distance between the vicinity of the center of the driver's side wall portion 31 and the periphery of the inflow opening 24 when inflation is complete. In this embodiment, the tether 33 is formed at two locations on both the left and right sides of the inflow opening 24. The tether 33 is composed of two tether base materials 53U and 53D as shown in Figure 8. Each tether base material 53U, 53D comprises mounting portions 54U, 54D that are connected to the vehicle body side wall portion 23 and the driver's side wall portion 31, respectively, and two tether components 55U, 55D that extend from the outer peripheral edges of the mounting portions 54U, 54D. The tether 33 is formed by connecting the ends of the corresponding tether components 55U, 55D with the mounting portions 54U, 54D connected to the vehicle body side wall portion 23 and the driver's side wall portion 31. The tether base materials 53U, 53D that constitute the tether 33 are formed from a flexible woven fabric made of polyamide yarn, polyester yarn, etc., similar to the bag body 21.

[0023] The flap material 36, acting as a control member (internal pressure control member), is capable of blocking the exhaust hole 29 formed in the bag body 21. In this embodiment, as shown in Figures 4 and 5, it is positioned on the outer circumferential side of the bag body 21. The flap material 36, like the bag body 21 and the tether 33, is formed from a flexible woven fabric made of polyamide yarn, polyester yarn, etc. The flap material 36 is set to a size that can block the exhaust hole 29. In this embodiment, its outer shape is approximately an isosceles triangle (see Figures 4 and 6). The flap material 36 is positioned so as to block the exhaust hole 29 from the outer circumferential side across its entire surface, with its base edge 36a aligned horizontally in front of the exhaust hole 29, its tip 36b positioned behind the exhaust hole 29, and its two slanted edges 36c and 36d positioned to the left and right of the exhaust hole 29, respectively. The base edge 36a of the flap material 36 is sewn (joined) to the bag body 21 (vehicle body side wall portion 23) along its entire length using suture thread T0 to form a suture portion 37. The tip 36b of the flap material 36 is sewn (joined) to the bag body 21 (vehicle body side wall portion 23) using conductive thread T1. Specifically, in the embodiment, as shown in Figure 7, the suture portion 38 to which the tip 36b of the flap material 36 is sewn to the vehicle body side wall portion 23 comprises an upper thread 39 and a lower thread 40. In this embodiment, of the upper thread 39 and lower thread 40 constituting the suture portion 38, the upper thread 39, which is arranged to be exposed on the outer surface side of the flap material 36, is made of conductive thread T1, and the lower thread 40, which is arranged to be exposed on the inner surface side of the vehicle body side wall portion 23, is made of a commonly used general suture thread T0 (specifically, a synthetic fiber thread made of polyamide thread, polyester thread, etc.). Lead wires 45, 45 are connected to both ends of the suture portion 38 where the tip 36b of the flap material 36 is sewn to the side wall portion 23 of the vehicle body (specifically, the ends 39a, 39b on both sides of the upper thread 39 made of conductive thread T1) (see Figure 7), and the suture portion 38 (upper thread 39) is electrically connected to the control device 60 (see Figure 1) provided on the vehicle body side via the lead wires 45, 45.In this embodiment, the conductive thread T1 (upper thread 39) constituting the suture site 38 is energized via lead wires 45, 45 when it receives an operating signal from the control device 60. When this energization occurs, it generates heat, melting the suture thread T0 (lower thread 40), causing the suture thread T0 (lower thread 40) to break apart.

[0024] As shown in Figure 1, the control device 60 is electrically connected to an occupant detection sensor (for example, a position detection sensor 65 that can detect the distance between the steering wheel W and the driver MD, and a weight detection sensor 66 that can detect the weight of the driver MD) that can detect the physique and seating position of the driver MD as an occupant seated in the seat (driver's seat) DS, and is also electrically connected to a collision detection sensor 67 that can detect the vehicle's acceleration and direction of acceleration. The control device 60 receives electrical signals from these position detection sensors 65, weight detection sensors 66, or collision detection sensors 67 to operate the inflator 9 and energize the conductive thread T1 (upper thread 39) that constitutes the suture portion 38 where the tip 36b of the flap material 36 is sewn to the side wall portion 23 of the vehicle body. The physique and seating position of the driver MD may also be detected by a camera capable of photographing the driver's seat.

[0025] Next, the manufacturing of the airbag 20 of the embodiment will be described. The base edge 36a side of the flap material 36 is sewn to the vehicle body side panel 50 in advance using suture thread T0 to form a stitched portion 37, and the tip 36b side of the flap material 36 is sewn to it using suture thread T0 and conductive thread T1 to form a stitched portion 38. The mounting side portion 54D of the tether base material 53D is placed on top of the vehicle body side panel 50 and sewn with suture thread at the periphery of the inlet opening 24, and the inlet opening 24 and mounting hole 25 are formed by drilling. The mounting side portion 54U of the tether base material 53U is sewn to the driver side panel 51. Next, the vehicle body side panel 50 and the driver side panel 51 are placed together in a flat, unfolded state with their outer surfaces in contact, and the outer edges 50a and 51a are sewn together using suture thread to form a bag-shaped body 21 with the flap material 36 attached. After inverting this bag body 21 using the inlet opening 24 so that the seam allowance is not exposed to the outside, the ends of the tether components 55U and 55D are joined together to form a tether, thereby manufacturing the airbag 20.

[0026] The airbag 20 manufactured in this manner can be installed in the vehicle as follows. Lead wires 45, 45 are connected to both ends (39a, 39b on both sides of the upper thread 39 made of conductive thread T1) of the stitching portion 38 where the tip 36b of the flap material 36 is sewn to the vehicle body side wall portion 23, and while maintaining the connection of these lead wires 45, 45, the airbag 20 is folded so that it can be stored inside the case 11. Specifically, the airbag 20 (bag body 21) is laid flat so that the vehicle body side wall portion 23 and the driver's side wall portion 31 overlap, with a retainer 7 positioned inside, with bolts (not shown) protruding from the mounting holes 25 (detailed illustration omitted), and is folded so that the width dimensions in the front, rear, left, and right directions are reduced so that it can be stored inside the case 11. At this time, the flap material 36 is also folded together with the bag body 21. The folded airbag 20 is then stored inside the case 11. At this time, the lead wires 45, 45 extending from the folded airbag 20 are inserted into predetermined insertion holes (not shown) formed in the case 11. The main body 9a of the inflator 9 is inserted from below, and the inflator 9 and airbag 20 are attached to the case 11 using bolts and nuts (not shown) protruding from the bottom wall 12. Furthermore, the airbag cover 15 is placed over the case 11, and the airbag cover 15 is attached to the case 11 using rivets or the like. The horn switch mechanism (not shown) is then assembled to the mounting piece 13a of the case 11, thereby completing the airbag device M. This airbag device M can be mounted on a vehicle by attaching it to the steering wheel body 1, which has been previously fastened to the steering shaft SS, using a mounting board (not shown) for the horn switch mechanism. When mounted on the vehicle, the inflator 9 and the lead wires 45, 45 extending from the tip 36b side of the flap material 36 of the airbag 20 are electrically connected to the control device 60.

[0027] In the airbag device M of this embodiment, when inflation gas is discharged from the gas outlet 9b of the inflator 9, the airbag 20 inflates by allowing the inflation gas to flow into its interior, pushing open the door portions 15b, 15b of the airbag cover 15 and protruding from the case 11, completing the inflation so as to cover substantially the entire upper surface of the steering wheel W, as shown by the dashed lines in Figures 1 and 2 and in Figure 9.

[0028] In the airbag device M of this embodiment, a control member (flap material 36 in this embodiment) capable of controlling the inflation state of the bag body 21 is configured to be connected to the bag body 21 at least at one end, and the inflation state of the bag body 21 is controlled by maintaining or releasing this connection to the bag body 21. This control member (flap material 36) is configured to be connected to the bag body 21 at one end (tip 36b) by a suture portion 38, and this suture portion 38 (upper thread 39 constituting the suture portion 38 in this embodiment) is made of conductive thread T1. The conductive thread T1 is electrically connected to the control device 60, and when power is applied, it is possible to release this sewn state (connected state) by severing a predetermined part of the suture portion 38 (lower thread 40 made of suture thread T0 in this embodiment). In other words, in the airbag device M of the embodiment, by energizing the conductive thread T1 (upper thread 39) that constitutes the suture portion 38 connecting at least one end (tip 36b) of the flap material 36, which acts as a control member, to the bag body 21 at a predetermined time, the connection between the tip 36b of the flap material 36 and the bag body 21 can be released. By maintaining or releasing this connection between the tip 36b of the flap material 36 and the bag body 21, the inflation state of the bag body 21 can be changed. Therefore, since the inflation state of the airbag (bag body) can be controlled without using a squib, as in conventional airbag devices, the configuration can be simplified. Furthermore, it is possible to reduce manufacturing costs, reduce weight, and make the device itself more compact. Of course, in the airbag device M of the embodiment, since the inflation state of the airbag 20 can be controlled, the driver MD as an occupant can be accurately protected by the airbag 20 once it has finished inflating.

[0029] Therefore, the airbag device M of this embodiment can effectively protect the driver MD as an occupant with a simple configuration.

[0030] Specifically, in the airbag device M of the embodiment, a flap material 36 capable of closing the exhaust hole 29 formed in the bag body 21 is provided as a control member (internal pressure control member) that can control the inflation state of the bag body 21 (can control the internal pressure when inflation is complete).

[0031] In the airbag device M of this embodiment, when the control device 60, which receives signals from predetermined sensors 65, 66, and 67, detects, for example, the presence of a small driver MD1 or the driver MD being seated in a position close to the steering wheel W, it energizes the conductive thread T1 (upper thread 39) that constitutes the suture portion 38 where the tip 36b side of the flap material 36 is sewn to the vehicle body side wall portion 23, via lead wires 45, 45, almost simultaneously with the operation of the inflator 9. This causes the conductive thread T1 (upper thread 39) to heat up, partially melting the suture thread T0 (lower thread 40) and severing the suture thread T0 (lower thread 40). As a result of this separation, the lower thread 40 may come loose, releasing the connection (sewn state) between the tip 36b of the flap material 36 and the vehicle body side wall 23 at the sutured area 38. The airbag 20 then inflates in an open mode, opening the exhaust port 29, as shown in Figure 10, and completes inflation by exhausting excess inflation gas from the exhaust port 29. Therefore, since the airbag 20 completes inflation while suppressing the rise in internal pressure by exhausting excess inflation gas G from the exhaust port 29, it is possible to protect the small driver MD1 or the driver MD seated close to the steering wheel W with a soft touch by preventing excessive pressure from being applied by the airbag 20, which is set to have a low internal pressure.

[0032] Conversely, if the control device 60 detects, for example, the presence of a large driver MD2 or the driver MD being seated relatively far from the steering wheel W, the conductive thread T1 (upper thread 39) constituting the suture portion 38, which sews the tip 36b of the flap material 36 to the vehicle body side wall portion 23, is not energized. The suture portion 38 is maintained, and the airbag 20 inflates in a closed mode, maintaining the closed state of the exhaust port 29 by the flap material 36. As shown in Figure 11, the airbag 20 completes inflation while maintaining this closed state of the exhaust port 29. Therefore, since the airbag 20 completes inflation with high internal pressure without releasing the inflation gas from the exhaust port 29, a large driver MD2 or a driver MD seated relatively far from the steering wheel W can be accurately protected by an airbag that has been inflated with sufficient internal pressure and cushioning properties, without bottoming out.

[0033] In the airbag device M of this embodiment, the flap material 36 is shaped like a roughly isosceles triangle, with the base edge 36a being sewn (joined) to the vehicle body side wall 23 along its entire length, and the tip 36b being sewn using conductive thread T1. When the airbag is inflated in a closed mode, maintaining the closed state of the exhaust port 29 by the flap material 36, the flap material 36 applies tension T (see Figure 6) near the two hypotenuse edges 36c and 36d, respectively, along the lines connecting the ends of the sewn portions 37 and 38, thereby closing the exhaust port 29 provided in the bag body 21. In this embodiment, the exhaust port 29 is formed in the vehicle body side wall 23 of the bag body 21 in a region that is located inside the ring portion R of the steering wheel W when inflation is complete. Since such regions are arranged in a substantially planar manner on the bag body 21 when inflation is complete, the exhaust port 29 and the flap material 36 that closes the exhaust port 29 from the outside are also arranged in a substantially planar manner on the vehicle side wall portion 23 of the airbag 20 (bag body 21) when inflation is complete. Therefore, when inflating the airbag 20 while maintaining the connection between the tip 36b of the flap material 36 and the vehicle side wall portion 23 by the suture portion 38 (closed mode), tension T acts near the edges 36c and 36b of the flap material 36. However, gaps are unlikely to form between the tension generation area (the area on the edge 36c and 36d side) and the vehicle side wall portion 23, and gas leakage from the exhaust port 29 can be suppressed as much as possible. In other words, in the airbag device M of the embodiment, the exhaust port 29 can be stably closed even if the flap material 36 is in the shape of an isosceles triangle.

[0034] The arrangement of the flap material 36 and the exhaust hole 29, as well as the external shape of the flap material 36, are not limited to this embodiment. The flap material and exhaust hole may be arranged in the outer peripheral edge region located on the outer peripheral side of the vehicle side wall portion of the bag body when inflation is complete, on the outer peripheral side of the ring portion R. Furthermore, the flap material may be made in a substantially rectangular shape, with the suture portion (connection portion with conductive thread) at the tip arranged along the entire length in the width direction of the flap material, or the flap material may be arranged on the inner peripheral surface side of the bag body.

[0035] Furthermore, in the airbag device M of the embodiment, the airbag 20 is configured to have two vent holes 27, 27 that are always open, separate from the exhaust hole 29, but the presence or absence of vent holes that are always open is not particularly limited. Depending on the occupant protection mode, the presence or absence, size, and number of vent holes can be changed as appropriate. Moreover, although the embodiment uses an airbag device M for a steering wheel as an example, the airbag device to which the present invention can be applied is of course not limited to a steering wheel, and the present invention may be applied to, for example, an airbag device for the passenger seat. Furthermore, in the embodiment, a flap material 36 that can close the exhaust hole 29 provided in the bag body 21 is provided as a control member that can control the inflation state of the bag body 21, and the internal pressure when the inflation of the airbag 20 is complete is controlled, but the control of the inflation state of the airbag 20 (bag body 21) is not limited to internal pressure control. For example, a protruding expansion section that can partially protrude from the bag body may be provided as a control member to create different completed expansion shapes, and the end of a tether or the like that pulls this protruding expansion section may be connected to the bag body side by a conductive thread, thereby creating a configuration that allows for different completed expansion shapes depending on the mode.

[0036] In the airbag device M of this embodiment, the suture portion 38 to which the tip 36b of the flap material 36 is sewn to the bag body 21 is configured to have an upper thread 39 and a lower thread 40, with one thread (upper thread 39) made of conductive thread T1 and the other thread (lower thread 40) made of general suture thread T0. However, the form of the suture portion is not limited to this embodiment. For example, the suture portion may be formed from only one thread made of conductive thread, without having two threads, an upper thread and a lower thread. Alternatively, both the upper and lower threads constituting the suture portion may be made of conductive thread. Furthermore, in this embodiment, the upper thread 39 made of conductive thread T1 generates heat and melts the lower thread 40 made of general suture thread T0, thereby separating a predetermined location. However, the conductive thread itself may separate the predetermined location by melting due to heat, without melting the suture thread. [Explanation of symbols]

[0037] 9...Inflator, 11...Case, 15...Airbag cover, 20...Airbag, 21...Bag body, 23...Vehicle side wall, 29...Exhaust vent, 36...Flap material (control component), 36b...Tip, 38...Suture site, 39...Upper thread, 40...Lower thread, 45...Lead wire, 60...Control device, T1...Conductive thread, MD (MD1, MD2)...Driver (occupant), W...Steering wheel, M...Airbag device.

Claims

1. An airbag system comprising an airbag configured to inflate to protect occupants seated in seats in a vehicle by introducing an inflating gas into its interior, and to control the inflation state, The airbag comprises a bag body and a control member capable of controlling the inflation state of the bag body. The control member is connected to the bag body by sewing at least one end to it using conductive thread, and the expansion state of the bag body is controlled by maintaining or releasing the connection state of the one end to the bag body by the conductive thread. The suture portion connecting at least one end of the control member to the bag body is made of the conductive thread, An airbag device characterized in that the conductive thread is electrically connected to a control device, and when energized, it can sever a predetermined portion of the sutured area, thereby releasing the connection between one end of the control member and the bag body.

2. The suture site is configured to include an upper thread and a lower thread. The airbag device according to claim 1, characterized in that at least one of the upper thread or the lower thread is made of the conductive thread.

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