Variable vent mechanism, airbag system, and flap mechanism

Abstract

To provide a technique that enables a heat generation device to be stably mounted on a mating member with a small number of components.SOLUTION: A variable vent mechanism is provided with: an airbag having a vent hole 21 in an opening shape on a bag wall surface; a flap 4 mounted on the airbag to cover the vent hole 21, at a first fixed part 41; a strap 5 that is extended from a connection end part 43 of the flap 4 to be positionally fixed to a closing position where the vent hole 21 is closed, at a second fixed part 52; and a closing release device that releases the strap 5 and changes a position of the flap 4 from the closing position. A relation between a maximum length L3 between the first fixed part 41 and the connection end part 43 in a first direction in which the first fixed part 41 is joined to the second fixed part 52 and a maximum length L4 of the first fixed part 41 in a second direction which is orthogonal to the first direction satisfy a relational expression of 0.5≤L3 / L4≤3.0, where the length in the second direction is shorter at the connection end part 43 than at the first fixed part 41.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a variable vent mechanism, an airbag device including the variable vent mechanism, and a flap mechanism included in the variable vent mechanism.

Background Art

[0002] At the time of a vehicle collision, an inflation fluid such as gas generated by an inflation fluid source such as an inflator is supplied to an airbag connected to the inflation fluid source, and the airbag is deployed and inflated between the vehicle body and the occupant to protect the occupant. Various airbag devices are known.

[0003] In an airbag device, for the convenience of protecting the occupant from the impact of a collision, it is necessary to supply a sufficient amount of inflation fluid to the airbag quickly during its deployment and inflation. However, on the other hand, the airbag applies a large reaction force to the occupant, which causes significant discomfort to the occupant. If the reaction force is excessive, it will give a large impact to the occupant, and as a result, there is a risk of burdening the occupant's body.

[0004] In order to avoid the above problems during the deployment and inflation of an airbag, a technique of providing a variable vent mechanism in an airbag device has been proposed. In an airbag device provided with the variable vent mechanism, an opening-shaped vent hole is provided in the airbag.

[0005] In an airbag device having a variable vent mechanism, at an initial stage during the deployment and inflation of the airbag, the vent hole is closed to supply a sufficient amount of inflation fluid to the airbag quickly and increase the internal pressure of the airbag to a sufficient level to protect the occupant. Then, by opening the vent hole thereafter, the inflation fluid in the airbag is allowed to flow out to the outside, and the internal pressure of the airbag is reduced. Thereby, it is possible to reduce the above reaction force applied to the occupant.

[0006] Various methods have been proposed for opening and closing the vent hole of an airbag (see, for example, Patent Document 1).

[0007] Patent Document 1 describes an airbag device (airbag cushion assembly 100) having a vent opening 112 provided in the airbag (airbag cushion 110) and a strap (tether 130) attached to the vent opening 112.

[0008] According to the technology described in Patent Document 1, the airbag is deployed and inflated with a strap closing the vent hole located at the vent opening of the airbag. Subsequently, by rupturing the strap, the vent hole opens, and the inflation fluid inside the airbag flows out to the outside. This can reduce the internal pressure of the airbag. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] U.S. Patent Application Publication No. 2017 / 0158161 [Overview of the project] [Problems that the invention aims to solve]

[0010] By the way, in the airbag device described in Patent Document 1, a portion of the bag-shaped airbag is narrowed into a thin cylindrical shape, and the end of this cylindrical portion is open to form a vent hole. Furthermore, when the vent hole is closed, this cylindrical portion is folded back inside the airbag and secured with a strap.

[0011] In the variable vent mechanism airbag described in Patent Document 1, as previously mentioned, a vent hole is formed at the end of a narrow, cylindrical portion of the airbag. By providing such a cylindrical portion, a larger amount of base fabric is required for the airbag, and the mass of the airbag also increases by the amount of this cylindrical portion.

[0012] Furthermore, in order to open the vent hole from a closed state, it is necessary not only to break the strap but also to unfold the tubular portion that has been folded inward into the airbag to the outside of the airbag. With this type of variable vent mechanism, the above complex process is required to open the vent hole. For this reason, there is room for improvement in the responsiveness of the opening operation of the vent hole with this variable vent mechanism. Thus, conventional variable vent mechanisms had problems with their opening and closing operation characteristics being far from satisfactory.

[0013] This invention has been made in view of the above circumstances, and aims to solve the problem of providing a technology that can improve the opening and closing operation characteristics of a variable vent mechanism. [Means for solving the problem]

[0014] The variable vent mechanism of the present invention, which solves the above problems, An airbag that is bag-shaped and has an open vent hole on the wall surface of the bag, In the first fixing part, a flap is attached to the airbag and covers the vent hole, A strap extending from the connecting end of the flap and fixed to the strap attachment part at the second fixing part to fix the flap in a closed position that closes the vent hole, The device comprises a release mechanism that frees the strap and changes the position of the flap from the closed position, In the aforementioned flap, The relationship L3 / L4 between the maximum length L3 between the first fixing part and the connecting end in the first direction connecting the first fixing part and the second fixing part, and the maximum length L4 of the first fixing part in the second direction perpendicular to the first direction, satisfies 0.5 ≤ L3 / L4 ≤ 3.0. The length in the second direction is shorter on the connection end side than on the first fixed part side, making it a variable vent mechanism.

[0015] Furthermore, the airbag device of the present invention that solves the above problems is an airbag device equipped with the variable vent mechanism of the present invention described above.

[0016] The flap mechanism of the present invention for solving the above problems is a flap mechanism included in the variable vent mechanism of the present invention described above, a flap that is attached at a first fixing portion to an airbag having a bag shape and having an opening-shaped vent hole in its bag wall surface, and covering the vent hole; a strap that extends from a connection end portion of the flap and is fixed to a strap attachment portion at a second fixing portion to fix the position of the flap in a closed position for closing the vent hole; and, in the flap, the relationship L3 / L4 between the maximum length L3 of the first fixing portion and the connection end portion in a first direction connecting the first fixing portion and the second fixing portion, and the maximum length L4 of the first fixing portion in a second direction orthogonal to the first direction, satisfies 0.5 ≦ L3 / L4 ≦ 3.0, the length in the second direction is shorter on the connection end portion side than on the first fixing portion side, which is a flap mechanism.

[0017] According to the variable vent mechanism, airbag device, and flap mechanism of the present invention, it is possible to improve the opening / closing operation characteristics of the variable vent mechanism.

Brief Description of the Drawings

[0018] [Figure 1] It is an explanatory diagram schematically explaining an airbag device of Example 1 in a state where the airbag is deployed and inflated. [Figure 2] It is an explanatory diagram schematically explaining an airbag device of Example 1 in a state where the airbag is deployed and inflated. [Figure 3] It is an explanatory diagram schematically explaining a flap mechanism and a vent hole in an airbag device of Example 1. [Figure 4] It is an explanatory diagram schematically explaining a state where a flap closes a vent hole of an airbag in an airbag device of Example 1. [Figure 5]It is an explanatory diagram schematically illustrating a state where the flap closes the vent hole of the airbag in the airbag device of Example 1. [Figure 6] It is an explanatory diagram schematically illustrating a state where the flap opens the vent hole of the airbag in the airbag device of Example 1. [Figure 7] It is an explanatory diagram schematically illustrating a state where the flap opens the vent hole of the airbag in the airbag device of Example 1. [Figure 8] It is an explanatory diagram schematically illustrating the airbag device of Example 2 in a state where the airbag is deployed and inflated. [Figure 9] It is an explanatory diagram schematically illustrating the flap mechanism and the vent hole in the airbag device of the comparative example. [Figure 10] It is an explanatory diagram schematically illustrating the flap mechanism and the vent hole in the airbag device of Example 3. [Figure 11] It is an explanatory diagram schematically illustrating the flap mechanism and the vent hole in the airbag device of Example 4. [Figure 12] It is an explanatory diagram schematically illustrating the flap mechanism and the vent hole in the airbag device of Example 5. [Figure 13] It is an explanatory diagram schematically illustrating the flap mechanism and the vent hole in the airbag device of Example 6. [Figure 14] It is an explanatory diagram schematically illustrating the flap mechanism and the vent hole in the airbag device of Example 7. [Figure 15] It is an explanatory diagram schematically illustrating the flap mechanism and the vent hole in the airbag device of Example 8. [Figure 16] It is an explanatory diagram schematically illustrating the flap mechanism and the vent hole in the airbag device of Example 9.

Modes for Carrying Out the Invention

[0019] The variable vent mechanism of the present invention comprises an airbag, a flap, a strap, and a closure release device.

[0020] The airbag is bag-shaped and has an open vent hole on its wall. The vent hole is covered by a flap, and the flap is further secured in a closed position by a strap extending from the flap to close the vent hole. The release mechanism frees the strap. This causes the flap, which was fixed in the closed position, to change position. In other words, the vent hole opens at this time.

[0021] Thus, in the variable vent mechanism of the present invention, the vent hole is closed by a flap, so there is no need to provide a cylindrical portion in the airbag as described in Patent Document 1.

[0022] Furthermore, in the variable vent mechanism of the present invention, the flap is fixed in the closed position by a strap extending from it. Therefore, when the strap is released, the flap opens the vent hole.

[0023] Therefore, the variable vent mechanism of the present invention allows vent holes to be opened by a relatively simple mechanism of action and exhibits excellent responsiveness in the opening operation of the vent holes. In other words, the variable vent mechanism of the present invention can be said to have improved opening and closing operation characteristics.

[0024] Furthermore, in the variable vent mechanism of the present invention, the flap is attached to the airbag at the first fixing part. Also, the strap extending from the connecting end of the flap is fixed to the strap attachment part at the second fixing part. Therefore, tension acts on the integrated flap and strap in the first direction, that is, in the direction connecting the first fixing part and the second fixing part.

[0025] In such a flap, the relationship L3 / L4 between the maximum length L3 between the first fixed portion and the connecting end in the first direction and the maximum length L4 of the first fixed portion in the second direction perpendicular to the first direction satisfies 0.5 ≤ L3 / L4 ≤ 3.0. Furthermore, in this flap, the length in the second direction is shorter on the connecting end side than on the first fixed portion side.

[0026] By shaping the flap as described above, it is possible to increase the tension acting on the flap and strap when the vent hole is closed. This increased tension allows the flap and strap to effectively close the vent hole. Furthermore, if the tension is high, the reaction force when the strap is released is also increased, allowing the vent hole to open quickly.

[0027] These collaborations further improve the opening and closing characteristics of the variable vent mechanism of the present invention.

[0028] Furthermore, according to the variable vent mechanism of the present invention, as described above, by increasing the tension acting on the flap and strap in the closed position to effectively close the vent hole, the airbag device can be given the function of sufficiently restraining the occupant during the initial stages of airbag deployment and inflation. Moreover, by quickly opening the vent hole thereafter, the airbag device can be given the function of quickly and sufficiently reducing the reaction force applied to the occupant, thereby effectively reducing the burden on the occupant's body.

[0029] The flap mechanism of the present invention is a flap mechanism included in the variable vent mechanism of the present invention. Therefore, the flap mechanism of the present invention, as described above, can improve the opening and closing characteristics of the variable vent mechanism. Furthermore, the flap mechanism of the present invention, as described above, has the advantage of providing the airbag device with the function of sufficiently restraining the occupant during the initial stages of airbag deployment and inflation, and the function of effectively reducing the burden on the occupant's body.

[0030] The airbag device of the present invention is an airbag device that includes the variable vent mechanism of the present invention described above. With this airbag mechanism of the present invention, the opening and closing characteristics of the variable vent mechanism are improved, similar to the variable vent mechanism of the present invention described above. Furthermore, similar to the variable vent mechanism of the present invention described above, it has the advantage of being able to sufficiently restrain the occupant during the initial stages of airbag deployment and inflation, and effectively reduce the burden on the occupant's body.

[0031] The variable vent mechanism, the flap for the variable vent mechanism, and the airbag device of the present invention will be described below, component by component. Unless otherwise specified, the components are common to the variable vent mechanism, the flap for the variable vent mechanism, and the airbag device of the present invention.

[0032] Furthermore, unless otherwise specified, the numerical range "x~y" described herein includes a lower limit x and an upper limit y. These upper and lower limits, along with the numerical values ​​listed in the examples, can be arbitrarily combined to form new numerical ranges. Moreover, any numerical values ​​arbitrarily selected from any of the above numerical ranges can be used as the upper and lower limits of a new numerical range.

[0033] As previously described, the airbag device of the present invention is an airbag device that includes the variable vent mechanism of the present invention, and the flap mechanism of the present invention is a flap mechanism included in the variable vent mechanism of the present invention. For this reason, the variable vent mechanism will be described below first.

[0034] [Variable vent mechanism] The variable vent mechanism is part of the airbag system and, as previously described, adjusts the internal pressure of the airbag by opening and closing vent holes provided in the airbag.

[0035] Specifically, the variable vent mechanism of the present invention comprises an airbag, a flap, a strap, and a closure release device.

[0036] In this case, the airbag is bag-shaped and has an opening-shaped vent hole on the wall surface of the bag. In other words, the vent hole in the variable vent mechanism of the present invention is not a part of the bag-shaped airbag as described in Patent Document 1, and is not provided at the end of a narrow, cylindrical portion, but is directly provided on the wall surface itself that constitutes the main bag-shaped part of the airbag.

[0037] Therefore, unlike the airbag described in Patent Document 1, the airbag in the variable vent mechanism of the present invention does not require a narrow cylindrical portion. Instead of folding back the narrow cylindrical portion to close the vent hole, the variable vent mechanism of the present invention uses a flap and a strap to close the vent hole that opens into the bag wall.

[0038] An airbag is a bag-shaped device that, as previously described, is connected to an inflation fluid source and protects the occupant by receiving the supply of inflation fluid upon impact, deploying, and inflating. The airbag may be placed anywhere in the vehicle, but it is particularly preferable that it be mounted on the steering wheel or on the back of the instrument panel, in front of the passenger seat, so as to be interposed between the occupant and the windshield.

[0039] Such airbags are normally folded and stored. Therefore, it is preferable to select a material for the airbag that is both foldable and deployable.

[0040] As for the specific material of the airbag, it is preferable to select a material that is flexible and high-strength, and for example, woven fabrics using high-strength resin fibers such as polyester and polyamide can be used particularly suitably.

[0041] An open vent hole is provided on the bag wall of the airbag. An airbag may have only one vent hole or multiple vent holes. The vent hole only needs to connect the inside and outside of the airbag and allow the inflation fluid inside the airbag to be discharged to the outside. If an airbag has multiple vent holes, each vent hole may have the same shape or different shapes.

[0042] In the variable vent mechanism of the present invention, the shape of the vent hole is not particularly limited and may be, for example, perfectly circular, but it is preferable that it be elongated. The elongated vent hole may have its longitudinal direction oriented in any direction, but it is preferable that its longitudinal direction be oriented in the first direction described above. In this specification, the longitudinal direction of the vent hole means the direction in which the opening diameter of the vent hole is largest. The short direction of the vent hole means the direction perpendicular to the longitudinal direction.

[0043] The elongated vent hole is preferably shaped like a track in athletics, where the ends of two straight lines extending in the longitudinal direction are connected by a curve. Specifically, examples include a shape formed by connecting two perfect circles of equal radius with a common outer tangent (a so-called ellipse or simple circle), a shape formed by connecting two ellipses of equal radius with a common outer tangent, or a shape where the corners of a rectangle are curved. The elongated vent hole may also be an ellipse.

[0044] In order to secure a larger opening area for vent holes provided in a limited space, it is particularly preferable for the vent holes to have a shape in which the ends of two straight lines extending in the longitudinal direction are connected by a curve.

[0045] In the variable vent mechanism of the present invention, if the airbag has multiple vent holes, one vent hole may be elongated, while the other vent holes do not necessarily have to be elongated.

[0046] When the vent hole is in the shape of a long hole, the maximum length L1 in the first direction and the maximum length L2 in the second direction orthogonal to the first direction in the vent hole only need to satisfy L1 > L2, but there is a preferable relationship between L1 and L2. Specifically, in the variable vent mechanism of the present invention, the relationship L1 / L2 between L1 and L2 preferably satisfies 1.0 < L1 / L2 ≦ 3.0, 1.05 ≦ L1 / L2 ≦ 3.0, 1.1 ≦ L1 / L2 ≦ 3.0, or 1.2 ≦ L1 / L2 ≦ 3.0.

[0047] Although the reason will be described in detail later, if the relationship L1 / L2 between L1 and L2 is within the above range, there is an advantage that the shape of the flap can be made into a shape capable of obtaining stronger tension.

[0048] By the way, as described above, since the vent hole in the variable vent mechanism of the present invention is provided on the bag wall surface of the airbag, the airbag in the variable vent mechanism of the present invention does not require a long and narrow cylindrical portion for providing the vent hole. However, as long as the airbag in the variable vent mechanism of the present invention has nothing to do with the vent hole, it may have a long and narrow cylindrical portion.

[0049] The flap is attached to the airbag and covers the vent hole. On the other hand, the strap extends from the flap and is fixed to the strap attachment portion which is the mating member, and fixes the flap in the position (closed position) for closing the above-described vent hole. The strap may be fixed to the strap attachment portion via a fixing material, or may be directly fixed to the strap attachment portion by being tied to the strap attachment portion or the like.

[0050] As described above, when the airbag has a plurality of vent holes, the flap may cover all the vent holes. In other words, the variable vent mechanism of the present invention may have the same number of flaps corresponding to each vent hole. Alternatively, if the airbag has multiple vent holes, the flap may cover only some of the vent holes, leaving the remaining vent holes uncovered. If some of the vent holes are elongated and the remaining vent holes are not, it is preferable to cover the elongated vent holes with the flap.

[0051] The flap must be able to cover the vent hole when closed, and be able to move away from the vent hole and open the vent hole when open.

[0052] Such flaps have a first fixing point that attaches to the airbag. A strap extends from the connecting end of the flap.

[0053] The first fixing portion can also be said to be located at one end of the flap in the first direction. Preferably, the connecting end is located at the other end of the flap in the first direction.

[0054] In the variable vent mechanism of the present invention, the flap satisfies the relationship L3 / L4 between the maximum length L3 between the first fixed portion and the connecting end in the first direction and the maximum length L4 of the first fixed portion in the second direction, which satisfies 0.5 ≤ L3 / L4 ≤ 3.0. Furthermore, the length in the second direction of the flap is shorter on the connecting end side than on the first fixed portion side.

[0055] The reason for this will be explained in detail later, but by giving the flap this shape, the tension acting on the flap in the closed position can be increased, and the vent holes can be opened more quickly in the open position.

[0056] There are various flap shapes that satisfy these conditions, and in any case it is possible to obtain sufficient tension in the closed position that closes the vent hole, but there are particularly preferred shapes for the flap. The above L3 / L4 values ​​are more preferably satisfied with 0.7 ≤ L3 / L4 ≤ 2.0, 0.75 ≤ L3 / L4 ≤ 1.5, or 0.8 ≤ L3 / L4 ≤ 1.5.

[0057] Furthermore, in the variable vent mechanism of the present invention, the length of the flap in the second direction only needs to be shorter on the connection end side than on the first fixed part side. For example, the flap may have a portion on the connection end side that is shorter in the second direction than on the first fixed part side. Alternatively, the length of the flap in the second direction may gradually decrease from the first fixing part side toward the connecting end side.

[0058] In the variable vent mechanism of the present invention, it is particularly preferable that the region of the flap on the connection end side is sandwiched between the first and second sides, and that it has a tapered shape in which the distance between the first and second sides decreases from the first fixing part side toward the connection end side.

[0059] By giving the flap the various shapes described above, it is possible to further increase the tension acting on the flap in the closed position.

[0060] When the region on the connecting end side of the flap has the tapered shape described above, it is preferable that the angle θ between the first and second sides is not excessive in order to avoid tension dispersion. Specifically, it is preferable that the angle θ is 150° or less, and particularly preferable that it is within the range of 30°≦θ≦120°, 60°≦θ≦110°, or 80°≦θ≦100°.

[0061] The material of the flap is not particularly limited, but it is preferable that it folds together with the airbag and does not hinder the deployment and inflation of the airbag. As such a flap material, it is preferable to select a material that is flexible and high strength, and it is particularly preferable to select a woven fabric using high-strength resin fibers such as polyester or polyamide, similar to the airbag.

[0062] The first fixing point of the flap is attached to the airbag. Any method of attaching the flap to the airbag is acceptable, as long as it does not hinder the deployment or inflation of the airbag. For example, the airbag and flap may be molded as a single unit, or the flap may be molded separately from the airbag and then sewn, glued, or welded to the airbag.

[0063] The flap may cover the vent hole inside the airbag, or it may cover the vent hole outside the airbag.

[0064] The strap only needs to extend from the connecting end of the flap and be able to be fixed to the strap attachment part at the second fixing part, and may take the shape of a string or a band, but is not limited thereto.

[0065] The strap and flap may be formed as a single unit, or the strap may be formed separately from the flap and then sewn, glued, or welded to the flap. For the strap material, it is preferable to select a material that is both flexible and high-strength, and, similar to the flap, a woven fabric using high-strength resin fibers such as polyester or polyamide is particularly preferable.

[0066] When a strap is secured to a strap fixing part with a fixing material, it is preferable to select a material that is flexible and high-strength for the fixing material. Furthermore, if the fixing material is to be broken by heat, as in the embodiment described later, it is sufficient to select a fixing material that can be broken by heat. In this case, it is particularly preferable to select a thermoplastic, high-strength resin fiber such as polyester, polyamide, or polyethylene terephthalate as the material for the fixing material.

[0067] The attachment point for the strap, to which the strap is secured, may be part of the airbag system, or it may be a vehicle component or interior part located near the airbag system. For example, if the airbag system is mounted on the steering wheel, the strap may be secured to the steering wheel, or to the base (so-called bag plate) for attaching the airbag to the steering wheel. Alternatively, it may be secured to the airbag itself. In each of these cases, the steering wheel, the base, or the airbag becomes the attachment point for the strap.

[0068] When a strap is secured to a strap attachment point by a fastening material, the fastening material should be selected appropriately based on the positional relationship between the strap and the strap attachment point, their materials, and their shapes. For example, if the strap attachment point is an airbag, the fastening material is preferably in the form of a sewing thread that secures the strap to the airbag. In this case, if the fastening material is to be ruptured by the heat of the heating element, the fastening material is preferably made of a material that is easily ruptured by heat, such as a thermoplastic resin sewing thread. In this specification, "sewing thread" refers to any thread that can be used for sewing, and does not limit its material, spinning method, fiber length, etc.

[0069] The strap may be secured to the outside of the airbag or to the inside of the airbag.

[0070] [Airbag system] The airbag device of the present invention is equipped with the variable vent mechanism of the present invention described above. The components of the variable vent mechanism of the present invention have already been described.

[0071] The airbag device of the present invention may include an inflation fluid source for supplying inflation fluid to the airbag. The source of the expanding fluid is preferably an inflator that generates gas as the expanding fluid, but in some cases, it may also generate an expanding fluid other than gas, such as a liquid or gel.

[0072] The inflation fluid source can be any device for supplying inflation fluid to the airbag. For example, it may be a so-called pyrotype device having a gas generating agent that generates gas as inflation fluid, or it may be a so-called hybrid type device that ruptures the bulkhead of a high-pressure vessel and supplies the gas contained in the high-pressure vessel. The inflation fluid source may be located entirely outside the airbag, or partially or entirely inside the airbag.

[0073] The airbag system may comprise other components. Examples of such other components include, but are not limited to, a retainer that houses at least a portion of the inflation fluid source, a cover that surrounds at least a portion of the airbag, and a wire harness for electrically connecting the inflation fluid source and the airbag control device.

[0074] The variable vent mechanism, airbag device, and flap mechanism of the present invention will be described below with specific examples.

[0075] (Example 1) The airbag system of Example 1 is a driver's side airbag system mounted on the steering wheel of a vehicle. The airbag system of Example 1 includes the variable vent mechanism of Example 1 and the flap mechanism of Example 1, and the variable vent mechanism of Example 1 includes the flap mechanism of Example 1. Hereinafter, descriptions such as "in the airbag system of Example 1" may be read as "in the variable vent mechanism of Example 1" or "in the flap mechanism of Example 1" as appropriate.

[0076] Figures 1 and 2 show schematic diagrams illustrating the airbag device of Example 1 in the deployed and inflated state. Figure 1 schematically shows a cross-section of the airbag device of Example 1, and Figure 2 schematically shows the airbag of Example 1 as viewed from the steering wheel side. Figure 3 shows a schematic diagram illustrating the flap mechanism and vent holes in the airbag device of Example 1. Figures 4 and 5 show schematic diagrams illustrating the vent holes of the airbag in the airbag device of Example 1 with the flaps closed. Figures 6 and 7 show schematic diagrams illustrating the vent holes of the airbag in the airbag device of Example 1 with the flaps open. Figure 5 shows the vent holes and flaps shown in Figure 4 as viewed from the back. Figure 7 shows the vent holes and flaps shown in Figure 6 as viewed from the back.

[0077] As shown in Figure 1, the airbag device 1 of Embodiment 1 comprises an airbag 2, an inflation fluid source 3, a flap 4, a strap 5, a release / close device 6, a case 7, and a base 8. The base 8 is a component for attaching the airbag device 1 of Embodiment 1 to the steering wheel 90 of the vehicle.

[0078] Of these, the flap 4 and strap 5 constitute the flap mechanism 10 of Embodiment 1. In addition, the airbag 21, flap 4, strap 5, and closing / releasing device 6 constitute the variable vent mechanism 11 of Embodiment 1.

[0079] In the airbag 2 device 1 of Example 1, the inflation fluid source 3 is an inflator 3 that generates gas as the inflation fluid, and has an inflation fluid generating squib (not shown) for initiating gas generation in the inflator 3. The inflator 3 has a gas outlet 31 for blowing out the gas, and the inflation fluid generating squib is connected to a control device (not shown) for deploying and inflating the airbag 2, and operates by receiving power.

[0080] The airbag 2 is a hollow bag, and the gas outlet 31 of the inflator 3 described above is connected to the opening 20 of the airbag 2, allowing gas, or inflation fluid, to be supplied to the inside of the airbag 2.

[0081] As shown in Figures 2, 4, and 5, the bag wall 25 of the airbag 2 is provided with vent holes 21 that open in an elongated shape. The vent holes 21 connect the inside and outside of the airbag 2.

[0082] As shown in Figures 3 to 5, a flap 4 is sewn around the vent hole 21 of the airbag 2 with a first sewing thread 40. The part of the flap 4 that is sewn to the airbag 2 is referred to as the first fixing part 41.

[0083] As shown in Figure 3, a strap 5 is integrated with the connecting end 43 of the flap 4. Furthermore, the end of the strap 5 opposite to the flap 4 is sewn to the airbag 2 with a second sewing thread 45.

[0084] The airbag 2 in the airbag device 1 and variable vent mechanism 11 of Example 1 corresponds to the strap attachment portion in the airbag device 1 and variable vent mechanism of the present invention. The portion of the strap 5 sewn to the airbag 2 is referred to as the second fixing portion 52.

[0085] The strap 5 is sewn and secured to the airbag 2 at the second fixing part 52, thereby fixing the flap 4 in the closed position (see Figures 3 to 5) that closes the vent hole 21.

[0086] The direction connecting the first fixing part 41 and the second fixing part 52 is referred to as the first direction. The direction perpendicular to the first direction is referred to as the second direction.

[0087] In the airbag device 1 of Embodiment 1, the first fixing portion 41 is one end of the flap 4 in the first direction, and the connecting portion 43 is the other end of the flap 4 in the first direction.

[0088] For reference, in this specification, if the first fixing part 41 and the second fixing part 52 are parallel, the first direction is defined as the direction in which the straight line connecting the first fixing part 41 and the second fixing part 52 by the shortest distance extends, that is, the direction perpendicular to the first fixing part 41 and the second fixing part 52. If the first fixing part 41 and the second fixing part 52 are not parallel, the first direction is defined as the direction in which the straight line connecting the center of the first fixing part 41 and the center of the second fixing part 52 extends. In some cases, the first direction may also be defined as the direction in which the straight line connecting the centroid of the first fixing part 41 and the centroid of the second fixing part 52 extends.

[0089] In the airbag device 1 of Example 1, the flap 4 is made of the same nylon fabric as the airbag 2. The first sewing thread 40 that sews the flap 4 to the airbag 2 is also made of nylon, just like the airbag 2 and the flap 4.

[0090] As shown in Figure 3, in the flap 4 of the airbag device 1 of Embodiment 1, the relationship L3 / L4 between the maximum length L3 between the first fixing portion 41 and the connecting end 43 in the first direction and the maximum length L4 of the first fixing portion 41 in the second direction is approximately 0.8, satisfying 0.5 ≤ L3 / L4 ≤ 3.0. Furthermore, the length in the second direction of the flap 4 is shorter on the connecting end 43 side than on the first fixing portion 41 side.

[0091] In the airbag device 1 of Embodiment 1, the flap 4 is sandwiched between the first and second sides, and can be said to have a tapered shape in which the distance between the first and second sides decreases from the first fixing portion 41 side to the connecting end portion 43 side. In the airbag device 1 of Embodiment 1, the angle θ between the first side 401 and the second side 402 is approximately 55°.

[0092] As shown in Figure 3, the vent hole 21 is an elongated hole with its longitudinal direction oriented in the first direction. The vent hole 21 has a shape formed by connecting two perfect circles of equal radius with a common outer tangent. In the airbag device 1 of Embodiment 1, the relationship L1 / L2 between the maximum length L1 of the vent hole 21 in the first direction and the maximum length L2 of the vent hole 21 in the second direction is approximately 1.4.

[0093] As shown in Figure 3, the flap 4 has a roughly triangular shape that tapers from the first fixing portion 41 to the connecting end portion 43, and the first fixing portion 41 is linearly sewn to the inner surface of the airbag 2 around the vent hole 21. The strap 5 extends in the first direction from the connecting end portion 43 of the flap 4.

[0094] The strap 5 is made of the same nylon fabric as the airbag 2 and flap 4, and is in the shape of a narrow strip. The connecting end 43 of the strap 5 is integrated with the flap 4, and the second fixing part 52 of the strap 5 is sewn and fixed inside the airbag 2. As a result, the flap 4 is fixed in a closed position (Figures 4 and 5) inside the airbag 2, covering and closing the vent hole 21.

[0095] In the airbag device 1 of Example 1, the airbag 2 itself is the attachment part for the strap described above. Also, the second sewing thread 45 that sews the strap 5 to the airbag 2 is the fixing material 50.

[0096] As shown in Figure 1, the release device 6 has a heating device 60 and a cap 61 and is located outside the airbag 2. The release device 6 heats and breaks the second sewing thread 45, i.e., the fixing material 50. In the airbag device 1 of Example 1, the release device 6 is a squib.

[0097] The operation of the airbag device 1 in Example 1 will be described below.

[0098] When an impact such as a collision occurs to a vehicle equipped with the airbag device 1 of Example 1, the squib for generating the expansion fluid (not shown) is operated by the control device (not shown), and the inflator 3 generates gas, which is the expansion fluid. The gas generated by the inflator 3 is supplied to the inside of the airbag 2. As a result, the airbag 2 deploys and inflates. At this time, the flap 4 is in the closed position and the vent hole 21A of the airbag 2 is covered by the flap 4 (Figures 3 to 5).

[0099] Immediately after airbag 2 deploys and inflates, the control device activates the release device 6. The release device 6 then generates heat, which heats the fixing material 50. Since the fixing material 50 is made of nylon, a thermoplastic resin, it is heated and ruptures.

[0100] In the airbag device 1 of Embodiment 1, the device is set so that the release mechanism 6 operates and the fixing material 50 breaks when the occupant collides with the airbag 2.

[0101] Before deployment, i.e., when airbag 2 is folded, the flap 4 is secured in the closed position by the strap 5. Even when airbag 2 is deployed and inflated, the flap 4 remains secured in the closed position by the strap 5. When the fixing material 50 breaks, the strap 5 becomes free, and as a result, the flap 4 becomes free.

[0102] At this time, the gas generated by the inflator 3 continues to be supplied to the inside of the airbag 2. As a result, the gas pressure from the inside to the outside of the airbag 2 pushes the flap 4 outwards, causing it to start changing position from the open position that closes the vent hole 21 to the open position that opens the vent hole 21. When the flap 4 and the remaining part of the strap 5 connected to it come out of the airbag 2 through the vent hole 21, the vent hole 21 opens (Figures 6 and 7). At this time, it can be said that the flap 4 is positioned in the open position that opens the vent hole 21.

[0103] When the flap 4 opens the vent hole 21, the gas inside the airbag 2 can escape to the outside of the airbag 2 through the vent hole 21. As a result, the gas pressure inside the airbag 2 is sufficiently reduced, and the external force imposed on the occupant by the airbag 2 is also sufficiently reduced.

[0104] As shown in Figure 3, in the flap 4 of the airbag device 1 of Embodiment 1, the relationship L3 / L4 between the maximum length L3 of the first fixing portion 41 and the connecting end 43 in the first direction and the maximum length L4 of the first fixing portion 41 in the second direction is approximately 1.25, and it can be said that L4 is sufficiently large compared to L3. Therefore, the tension acting on the flap 4 and strap 5 in the closed position is sufficiently high and is not easily dispersed in the second direction. Accordingly, with the airbag device 1 of Embodiment 1, even with a relatively small area flap 4, the vent hole 21 can be effectively closed in the closed position.

[0105] Furthermore, because the tension acting on the flap 4 and strap 5 is sufficiently high in the closed position, the reaction force when the fixing material 50 is broken and the strap 5 is freed is also increased. As a result, the vent hole can be opened quickly according to the airbag device 1 of Example 1. Through the cooperation of these factors, the opening and closing operation characteristics of the variable vent mechanism 11 are improved according to the airbag device 1 of Example 1.

[0106] (Example 2) The airbag device 1 of Example 2 is substantially the same as the airbag device 1 of Example 1, except for the position of the vent holes. Below, the airbag device 1 of Example 2 will be described, focusing on the differences from the airbag device 1 of Example 1. Figure 8 shows a schematic diagram illustrating the airbag device 1 of Embodiment 2 in the state where airbag 2 is deployed and inflated.

[0107] In the airbag device 1 of Embodiment 1, the vent hole 21 was located on the upper central side of the airbag 2, whereas in the airbag device 1 of Embodiment 2, the vent hole 21 is located on the upper end of the airbag 2.

[0108] In this second embodiment of the airbag device 1, the vent hole 21 is provided on the bag wall surface 25 of the airbag 2, with its longitudinal direction facing the first direction. Furthermore, in the second embodiment of the airbag device 1, the variable vent mechanism 11 is the same as the variable vent mechanism 11 in the first embodiment of the airbag device 1, and the positional relationship between the flap 4 and strap 5 and the vent hole 21 is also the same as in the first embodiment of the airbag device 1. Therefore, the airbag device 1 of Example 2 also improves the opening and closing characteristics of the variable vent mechanism 11, similar to the airbag device 1 of Example 1.

[0109] (Comparative example) The comparative example airbag device 1 is substantially the same as the airbag device 1 of Example 1, except that the vent holes are perfectly circular and the shape of the flap mechanism 10. The comparative example airbag device 1 will be described below, focusing on the differences from the airbag device 1 of Example 1. Figure 9 shows a schematic diagram illustrating the flap mechanism 10 and vent holes in the comparative example airbag device 1.

[0110] As previously described, the vent hole 21 in the comparative example airbag device 1 is perfectly circular. Therefore, the relationship L1 / L2 between the maximum length L1 of the vent hole 21 in the first direction and the maximum length L2 of the vent hole 21 in the second direction is 1. Furthermore, in the comparative example airbag device 1, the angle θ between the first side 401 and the second side 402 is approximately 75°.

[0111] The flap 4 has a tapered shape in which its length in the second direction gradually decreases from the first fixing portion 41 side to the connecting end portion 43 side, and L3 / L4 is about 0.4, which does not satisfy 0.5 ≤ L3 / L4 ≤ 3.0.

[0112] Therefore, the tension acting on the flap 4 and strap 5 in the closed position is inferior in the comparative example airbag device 1 compared to the airbag device 1 of Example 1. Consequently, the flap 4 in the comparative example airbag device 1 cannot be said to effectively close the vent hole 21 in the closed position, nor can it be said to quickly open the vent hole 21.

[0113] (Example 3) The airbag device 1 of Example 3 is substantially the same as the airbag device 1 of Example 1, except that the vent holes are perfectly circular and the shape of the flap mechanism 10. The airbag device 1 of Example 3 will be described below, focusing on the differences from the airbag device 1 of Example 1. Figure 10 shows a schematic diagram illustrating the flap mechanism 10 and vent holes in the airbag device 1 of Example 3.

[0114] The vent hole 21 in the airbag device 1 of Example 3 is perfectly circular. Therefore, the relationship L1 / L2 between the maximum length L1 of the vent hole 21 in the first direction and the maximum length L2 of the vent hole 21 in the second direction is 1. Furthermore, in the airbag device 1 of Example 3, the angle θ between the first side 401 and the second side 402 is approximately 50°.

[0115] The flap 4 has a tapered shape in which its length in the second direction gradually decreases from the first fixing part 41 side to the connecting end 43 side, and L3 / L4 is approximately 1.0.

[0116] Therefore, in the airbag device 1 of Example 3, as with the airbag device 1 of Example 1, the tension acting on the flap 4 and strap 5 in the closed position is sufficiently large. As a result, in the airbag device 1 of Example 3, the flap 4 can effectively close the vent hole 21 in the closed position and can quickly open the vent hole 21. In other words, the opening and closing operation characteristics of the variable vent mechanism 11 are improved in the airbag device 1 of Example 3, as with the airbag device 1 of Example 1.

[0117] (Example 4) The airbag device 1 of Example 4 is substantially the same as the airbag device 1 of Example 1, except that the vent holes are perfectly circular and the shape of the flap mechanism 10. The airbag device 1 of Example 4 will be described below, focusing on the differences from the airbag device 1 of Example 1. Figure 11 shows a schematic diagram illustrating the flap mechanism 10 and vent holes in the airbag device 1 of Example 4.

[0118] In the airbag device 1 of Example 4, the vent hole 21 is perfectly circular, and L1 / L2 is 1. Furthermore, in the airbag device 1 of Example 4, the angle θ between the first side 401 and the second side 402 is approximately 50°.

[0119] The flap 4 has a tapered shape in which its length in the second direction gradually decreases from the first fixing portion 41 side to the connecting end portion 43 side, and the first fixing portion 41 protrudes in an arc shape toward one end in the first direction, that is, toward the side opposite to the strap 5. The L3 / L4 in the airbag device 1 of Embodiment 4 is approximately 0.9.

[0120] In the airbag device 1 of this embodiment 4, L3 / L4 is sufficiently large, and in order to satisfy 0.5 ≤ L3 / L4 ≤ 3.0, the tension acting on the flap 4 and strap 5 in the closed position is sufficiently large. For this reason, the airbag device 1 of embodiment 4 also improves the opening and closing operation characteristics of the variable vent mechanism 11, similar to the airbag device 1 of embodiment 1.

[0121] (Example 5) The airbag device 1 of Example 5 is substantially the same as the airbag device 1 of Example 1, except for the shape of the flap mechanism 10. The airbag device 1 of Example 5 will be described below, focusing on the differences from the airbag device 1 of Example 1. Figure 12 shows a schematic diagram illustrating the flap mechanism 10 and vent holes in the airbag device 1 of Example 5.

[0122] In the airbag device 1 of Example 5, the vent hole 21 is elongated, and L1 / L2 is approximately 1.4. Furthermore, in the airbag device 1 of Example 5, the angle θ between the first side 401 and the second side 402 is approximately 90°.

[0123] The flap 4 has a first region 4f, which is the region on the connection end 43 side, and a second region 4s, which is the region on the first fixing portion 41 side. The first region 4f is sandwiched between the first side 401 and the second side 402, and has a tapered shape in which the distance between the first side 401 and the second side 402 decreases from the first fixing part 41 side to the connecting end 43 side. The second region 4s is sandwiched between the third side 403 and the fourth side 404, and has a tapered shape in which the distance between the third side 403 and the fourth side 404 decreases from the first fixing part 41 side to the connecting end 43 side. The angle θ between the first side 401 and the second side 402 is smaller than the angle θ0 (not shown in the diagram) between the third side 403 and the fourth side 404.

[0124] In the airbag device 1 of this embodiment 5, L3 / L4 is sufficiently large at approximately 0.9, satisfying 0.5 ≤ L3 / L4 ≤ 3.0, so the tension acting on the flap 4 and strap 5 in the closed position is sufficiently large. For this reason, the airbag device 1 of embodiment 5 also improves the opening and closing operation characteristics of the variable vent mechanism 11, similar to the airbag device 1 of embodiment 1.

[0125] (Example 6) The airbag device 1 of Example 6 is substantially the same as the airbag device 1 of Example 1, except for the shape of the flap mechanism 10. The airbag device 1 of Example 6 will be described below, focusing on the differences from the airbag device 1 of Example 1. Figure 13 shows a schematic diagram illustrating the flap mechanism 10 and vent holes in the airbag device 1 of Example 6.

[0126] In the airbag device 1 of Example 6, the vent hole 21 is elongated, and L1 / L2 is approximately 1.4. Furthermore, in the airbag device 1 of Example 6, the angle θ between the first side 401 and the second side 402 is approximately 90°.

[0127] In the airbag device 1 of Embodiment 6, the flap 4 also has a first region 4f which is the region on the connection end 43 side and a second region 4s which is the region on the first fixing part 41 side. The first region 4f is sandwiched between the first side 401 and the second side 402, and has a tapered shape in which the distance between the first side 401 and the second side 402 decreases from the first fixing part 41 side to the connecting end 43 side. The second region 4s is roughly rectangular in shape, bounded by the third side 403 extending in the first direction and the fourth side 404 also extending in the first direction.

[0128] In the airbag device 1 of this embodiment 6, L3 / L4 is large, approximately 1.4, and satisfies 0.5 ≤ L3 / L4 ≤ 3.0, so the tension acting on the flap 4 and strap 5 in the closed position is sufficiently large. For this reason, the airbag device 1 of embodiment 6 also improves the opening and closing operation characteristics of the variable vent mechanism 11, similar to the airbag device 1 of embodiment 1.

[0129] (Example 7) The airbag device 1 of Example 7 is substantially the same as the airbag device 1 of Example 1, except for the shape of the flap mechanism 10. The airbag device 1 of Example 7 will be described below, focusing on the differences from the airbag device 1 of Example 1. Figure 14 shows a schematic diagram illustrating the flap mechanism 10 and vent holes in the airbag device 1 of Example 7.

[0130] In the airbag device 1 of Example 7, the vent hole 21 is elongated, and L1 / L2 is approximately 1.4. Furthermore, in the airbag device 1 of Example 7, the angle θ between the first side 401 and the second side 402 is approximately 90°.

[0131] In the airbag device 1 of Embodiment 7, the flap 4 also has a first region 4f which is the region on the connection end 43 side and a second region 4s which is the region on the first fixing part 41 side. The first region 4f is sandwiched between the first side 401 and the second side 402, and has a tapered shape in which the distance between the first side 401 and the second side 402 decreases from the first fixing part 41 side to the connecting end 43 side. The second region 4s is sandwiched between the third side 403 and the fourth side 404, and has a tapered shape in which the distance between the third side 403 and the fourth side 404 decreases from the first fixing part 41 side to the connecting end 43 side. The angle θ between the first side 401 and the second side 402 is smaller than the angle θ0 (not shown in the diagram) between the third side 403 and the fourth side 404. The boundary between the first region 4f and the second region 4s is smoothly continuous. In other words, the first edge 401 and the third edge 403 are connected curvilinearly, and the second edge 402 and the fourth edge 404 are also connected curvilinearly.

[0132] In the airbag device 1 of this embodiment 7, L3 / L4 is large, approximately 1.0, and satisfies 0.5 ≤ L3 / L4 ≤ 3.0, so the tension acting on the flap 4 and strap 5 in the closed position is sufficiently large. For this reason, the airbag device 1 of embodiment 7 also improves the opening and closing operation characteristics of the variable vent mechanism 11, similar to the airbag device 1 of embodiment 1.

[0133] (Example 8) The airbag device 1 of Example 8 is substantially the same as the airbag device 1 of Example 1, except for the shape of the flap mechanism 10. The airbag device 1 of Example 8 will be described below, focusing on the differences from the airbag device 1 of Example 1. Figure 15 shows a schematic diagram illustrating the flap mechanism 10 and vent holes in the airbag device 1 of Example 8.

[0134] In the airbag device 1 of Example 8, the vent hole 21 is elongated, and L1 / L2 is approximately 1.4. Furthermore, in the airbag device 1 of Example 8, the angle θ between the first side 401 and the second side 402 is approximately 90°.

[0135] In the airbag device 1 of Embodiment 8, the flap 4 also has a first region 4f which is the region on the connection end 43 side and a second region 4s which is the region on the first fixing part 41 side. The first region 4f is sandwiched between the first side 401 and the second side 402, and has a tapered shape in which the distance between the first side 401 and the second side 402 decreases from the first fixing part 41 side to the connecting end 43 side. The second region 4s is roughly rectangular in shape, enclosed by the third side 403 and the fourth side 404, both extending in the first direction. The boundary between the first region 4f and the second region 4s is smoothly continuous. In other words, the first edge 401 and the third edge 403 are connected curvilinearly, and the second edge 402 and the fourth edge 404 are also connected curvilinearly.

[0136] In the airbag device 1 of this embodiment 8, L3 / L4 is large, approximately 1.4, and satisfies 0.5 ≤ L3 / L4 ≤ 3.0, so the tension acting on the flap 4 and strap 5 in the closed position is sufficiently large. For this reason, the airbag device 1 of embodiment 8 also improves the opening and closing operation characteristics of the variable vent mechanism 11, similar to the airbag device 1 of embodiment 1.

[0137] (Example 9) The airbag device 1 of Example 9 is substantially the same as the airbag device 1 of Example 1, except for the shape of the flap mechanism 10. The airbag device 1 of Example 9 will be described below, focusing on the differences from the airbag device 1 of Example 1. Figure 16 shows a schematic diagram illustrating the flap mechanism 10 and vent holes in the airbag device 1 of Example 9.

[0138] In the airbag device 1 of Example 9, the vent hole 21 is elongated, and L1 / L2 is approximately 1.4. Furthermore, in the airbag device 1 of Example 7, the angle θ between the first side 401 and the second side 402 is approximately 90°.

[0139] In the airbag device 1 of Example 9, the flap 4 also has a first region 4f which is the region on the connection end 43 side and a second region 4s which is the region on the first fixing part 41 side. The first region 4f is sandwiched between the first side 401 and the second side 402, and has a tapered shape in which the distance between the first side 401 and the second side 402 decreases from the first fixing part 41 side to the connecting end 43 side. The second region 4s is sandwiched between the third side 403 and the fourth side 404, and has a tapered shape in which the distance between the third side 403 and the fourth side 404 decreases from the first fixing part 41 side to the connecting end 43 side. The angle θ between the first side 401 and the second side 402 is smaller than the angle θ0 (not shown in the diagram) between the third side 403 and the fourth side 404.

[0140] In the airbag device 1 of Example 9, the vent hole 21 is located slightly offset in the second direction from the center of the flap 4 when it is in the closed position.

[0141] Furthermore, in the airbag device 1 of Embodiment 9, the connecting end 43 is also positioned slightly offset in the second direction from the center of the flap 4. Therefore, the length of the first fixing part 41 and the connecting end 43 in the first direction is much greater on one side in the second direction than on the other side.

[0142] In the airbag device 1 of this embodiment 9, the relationship L3 / L4 between the maximum length L3 of the first fixing portion 41 and the connecting end 43 in the first direction and the maximum length L4 of the first fixing portion 41 in the second direction is sufficiently large, at approximately 1.0, and satisfies 0.5 ≤ L3 / L4 ≤ 3.0. Therefore, the tension acting on the flap 4 and strap 5 in the closed position is sufficiently large. For this reason, the airbag device 1 of embodiment 9, like the airbag device 1 of embodiment 1, improves the opening and closing operation characteristics of the variable vent mechanism 11.

[0143] Although the present invention has been described above, the present invention is not limited to the embodiments described above, and it is possible to implement the invention by appropriately extracting and combining the elements described in the embodiments, and to make various modifications without departing from the spirit of the present invention. Furthermore, the specification of this invention discloses not only the reference relationships of each claim as initially filed, but also a technical concept that appropriately combines the matters described in each claim. [Explanation of Symbols]

[0144] 1: Airbag system 10: Flap mechanism 11: Variable venting mechanism 2: Airbag 2: Attachment point for strap (airbag) 21: Vent hole 25: Airbag bag wall 4: Flap 41: First fixing part 43: Connecting end 401: First side 402: Second side 5: Strap 52: Second fixing part 6: Close release device L1: Maximum length of the vent hole in the first direction L2: Maximum length of the vent hole in the second direction L3: Maximum length between the first fixing part and the connecting end 43 in the first direction. L4: Maximum length of the first fixing part in the second direction

Claims

1. An airbag that is bag-shaped and has an open vent hole on the wall surface of the bag, The first fixing part includes a flap that is attached inside the airbag and covers the vent hole from the inside, A strap extending from the connecting end of the flap and fixed to the strap attachment portion at the second fixing portion to fix the flap in a closed position that closes the vent hole, The device comprises a release mechanism that frees the strap and changes the position of the flap from the closed position, The first and second fixing portions are provided on the inner surface of the portion of the airbag that is located on the front side of the vehicle when deployed and inflated. In the aforementioned flap, The relationship L3 / L4 between the maximum length L3 between the first fixing part and the connecting end in the first direction connecting the first fixing part and the second fixing part, and the maximum length L4 of the first fixing part in the second direction perpendicular to the first direction, satisfies 0.5 ≤ L3 / L4 ≤ 3.

0. A variable vent mechanism wherein the length in the second direction is shorter on the connection end side than on the first fixed part side.

2. The vent hole has a long hole shape in which the maximum length L1 in the first direction is longer than the maximum length L2 in the second direction, and both ends in the longitudinal direction are formed in a curved shape. The variable vent mechanism according to claim 1, wherein in the flap, the relationship L3 / L4 between the maximum length L3 and the maximum length L4 satisfies 1.0 ≤ L3 / L4 ≤ 3.

0.

3. The variable vent mechanism according to claim 2, wherein the relationship L1 / L2 between the maximum length L1 and the maximum length L2 satisfies 1.0 < L1 / L2 ≤ 3.

0.

4. The region on the connecting end side of the flap is, It is enclosed by the first and second sides, The variable vent mechanism according to claim 1 or claim 2, wherein the shape tapers as the distance between the first side and the second side decreases from the first fixed portion side toward the connecting end side.

5. An airbag device comprising the variable vent mechanism described in claim 1 or claim 2.

6. An airbag, which is bag-shaped and has an open vent hole on its bag wall, has a flap attached at the first fixing part that covers the vent hole from the inside, The system comprises a strap extending from the connecting end of the flap and fixed to the strap attachment portion at the second fixing portion to fix the flap in a closed position that closes the vent hole, The first fixing portion and the second fixing portion are provided on the inner surface of the portion of the airbag that is located on the front side of the vehicle when deployed and inflated. In the aforementioned flap, The relationship L3 / L4 between the maximum length L3 between the first fixing part and the connecting end in the first direction connecting the first fixing part and the second fixing part, and the maximum length L4 of the first fixing part in the second direction perpendicular to the first direction, satisfies 0.5 ≤ L3 / L4 ≤ 3.

0. A flap mechanism wherein the length in the second direction is shorter on the connecting end side than on the first fixing part side.

7. The vent hole has a long hole shape in which the maximum length L1 in the first direction is longer than the maximum length L2 in the second direction, and both ends in the longitudinal direction are each formed in a curved shape. The flap mechanism according to claim 6, wherein the relationship L3 / L4 between the maximum length L3 and the maximum length L4 satisfies 1.0 ≤ L3 / L4 ≤ 3.0.

Images