airbag

Abstract

To provide an airbag that can achieve stable deployment behavior. [Solution] The airbag 11 comprises a main air chamber 15 having a gas inlet 23, and a conduit 16 that allows gas from the inflator 12 to flow into the main air chamber 15 from the gas inlet 23. The gas inlet 23 is open in a second direction intersecting the first direction in which the conduit 16 extends. The conduit 16 has an upper surface portion 27 which is a projection that protrudes in the second direction relative to the main air chamber 15. When the airbag 11 is folded, the upper surface portion 27 of the conduit 16 is folded back toward the main air chamber 15 and overlapped with the folded mass 15a of the main air chamber 15 on the side opposite to the inflator 12 in the first direction.

Description

Technical Field

[0001] The present invention relates to an airbag that allows gas from an inflator to flow from a gas introduction portion into a main air chamber via a conduit portion.

Background Art

[0002] Conventionally, in an airbag device mounted on a steering wheel of a vehicle such as an automobile, an opening is formed in the upper surface portion of a case body on the back side of the steering wheel, and the airbag bulging out from the opening is deployed toward an occupant seated on the front side of the steering wheel from the space between the rim portion and the hub portion. Such a configuration is known. In this configuration, the airbag has a conduit portion protruding from the opening of the case body, and an occupant-protecting main air chamber into which gas is introduced through the conduit portion, and the folded mass of the main air chamber is stored in the case body in a state of being overlapped with the conduit portion in the deployment direction (for example, refer to Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of Invention

Problems to be Solved by the Invention

[0004] In the case of the above configuration, it is required to prevent the main air chamber from coming into contact with the back surface of the rim portion of the steering wheel and delaying deployment, or preventing the main air chamber from deploying on the back surface side of the rim portion and causing unstable deployment behavior, due to the conduit portion and the main air chamber inflating at the same time.

[0005] The present invention has been made in view of the above points, and an object thereof is to provide an airbag capable of achieving stable deployment behavior.

Means for Solving the Problems

[0006] An airbag according to an aspect of the present invention comprises a main air chamber having a gas inlet and a conduit for allowing gas from an inflator to flow from the gas inlet into the main air chamber, wherein the gas inlet is opened in a second direction intersecting a first direction in which the conduit extends, the conduit has a projection that protrudes toward the main air chamber in the second direction, and in a folded state, the projection of the conduit is folded back toward the main air chamber and overlapped with the folded mass of the main air chamber on the side opposite to the inflator in the first direction. [Effects of the Invention]

[0007] According to the present invention, stable deployment behavior can be achieved. [Brief explanation of the drawing]

[0008] [Figure 1] (a) is a schematic cross-sectional view showing an airbag according to one embodiment of the present invention, (b) is a schematic cross-sectional view showing the folding process of the main air chamber in the folding method of the airbag, (c) is a view from arrow X in (b), (d) is a schematic cross-sectional view showing the process following (b) in the airbag folding method, and (e) is a schematic cross-sectional view showing the process following (d) in the airbag folding method. [Figure 2] This is a schematic cross-sectional view showing the initial stage of airbag deployment. [Figure 3] The above is a side view showing the deployed state of the airbag in the order of (a) to (e). [Figure 4] This is a front view of the steering wheel equipped with the same airbag. [Modes for carrying out the invention]

[0009] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

[0010] In Figures 1 to 4, 1 indicates an airbag device. The airbag device 1 in this embodiment is a driver's seat airbag device (DAB) and is mounted on the steering wheel 2 of a vehicle such as an automobile.

[0011] Here, the steering wheel 2 is mounted on the steering shaft 3, which is a steering shaft that is normally installed in the vehicle in an inclined position. In the following, the directions of up, down, forward, backward, left, and right are based on the perspective of an occupant seated in the driver's seat, with arrow U indicating the upper side, arrow D indicating the lower side, arrow FR indicating the front side, arrow RR indicating the rear side, arrow L indicating the left side, and arrow R indicating the right side. Furthermore, the position and shape of each part of the steering wheel 2 are described based on the neutral position.

[0012] The steering wheel 2 has a central boss portion 5 to which the airbag device 1 is attached and which is spline-connected to the steering shaft 3. Outside this boss portion 5 is a rim portion (grip) 6, which is a gripping portion for the driver or other occupant to grasp and operate. The boss portion 5 and the rim portion 6 are connected by spoke portions 7, which are connecting portions. In this embodiment, the rim portion 6 is exemplified as an annular or arc-shaped, but it may also be a steering stick type irregularly shaped steering wheel, also known as a yoke type.

[0013] The spoke portion 7 can be arbitrarily set as long as it can stably connect the rim portion 6 and the boss portion 5. In this embodiment, for example, the spoke portion 7 extends horizontally from the left and right sides of the boss portion 5, i.e., from the 9 o'clock to 3 o'clock position on an analog clock, and extends vertically from the bottom of the boss portion 5, i.e., from the 6 o'clock position on an analog clock. Therefore, in this embodiment, the handle 2 has an opening 8 formed between the upper part of the boss portion 5 and the rim portion 6. The opening 8 is formed to be larger in the horizontal direction than in the vertical direction, so as not to reduce the visibility of the meter located in front of the handle 2.

[0014] The airbag device 1 is located on the front side of the boss portion 5 of the steering wheel 2. The airbag device 1 comprises a case body 10, which houses an airbag 11 and an inflator 12, a gas generator that supplies gas G to the airbag 11. In the event of a vehicle collision, the introduced gas G causes the airbag 11 to inflate and deploy from the case body 10 to the front side of the steering wheel 2, protecting the occupants from the impact of the collision.

[0015] The case body 10 forms the pad of the boss portion 5. The case body 10 is usually divided into a box-shaped housing and a cover that covers the housing. The airbag 11 is stored in a folded state within the housing, which is attached to the core metal of the boss portion 5, and the inflator 12 is also attached to it. The cover is the part that faces the front of the occupant. The cover may be provided with a control panel or display unit operated by the occupant.

[0016] The case body 10 has tear lines formed on it as areas intended to break. The areas intended to break are configured to maintain the necessary strength of the case body 10 under normal circumstances, but to break in emergencies due to the inflation pressure of the airbag 11, forming an opening 13 in the case body 10 for the airbag 11 to protrude. For example, the tear lines are formed in a groove shape on the inner surface of the cover or housing of the case body 10, making the corresponding portion of the cover or housing a thin-walled portion. In this embodiment, the tear lines are formed on the upper part of the case body 10 in front of the rim portion 6 of the handle 2. For example, the tear lines are formed in an H-shape or a U-shape, and extend in the front-rear and left-right directions.

[0017] The airbag 11 is formed in the shape of a bag that inflates when gas G is introduced. The airbag 11 is folded into a predetermined folded shape and stored inside the case body 10, and is inflated and deployed by gas G introduced from the inflator 12.

[0018] The airbag 11 of the present embodiment at least includes a main chamber (main bag) 15 and a conduit portion 16.

[0019] The main chamber 15 is for occupant restraint, which deploys in up-down and left-right directions on the front face that is the occupant side of the steering wheel 2, and protects and restrains the occupant thrown forward. The main chamber 15 has a circular shape when viewed from the front, for example, in an inflated and deployed state or in a non-inflated unfolded state. The outer shape of the main chamber 15 is larger than the outer shape of the steering wheel 2, and has a size that covers the steering wheel 2 when viewed from the front in the inflated state.

[0020] In the main chamber 15, an occupant-side panel 20 located on the occupant side, that is, the rear side, in the inflated state, and a non-occupant-side panel 21 located on the opposite side, that is, the steering wheel 2 side, the front side, are provided.

[0021] The occupant-side panel 20 is a surface that faces the occupant and protects and restrains the occupant when the airbag 11 or the main chamber 15 is in the inflated and deployed state. The non-occupant-side panel 21 is a surface that faces the steering wheel 2 and generates a reaction force when the airbag 11 or the main chamber 15 is in the inflated state. The occupant-side panel 20 and the non-occupant-side panel 21 are each formed in a circular shape when viewed from the front. The occupant-side panel 20 and the non-occupant-side panel 21 each consist of one or a plurality of base fabric sheets. At least one of the occupant-side panel 20 and the non-occupant-side panel 21 may have a reinforcing panel such as a reinforcing cloth for reinforcement superimposed on the inner side at a predetermined position, or may be subjected to coating or the like. The peripheral edge portions of the occupant-side panel 20 and the non-occupant-side panel 21 are joined to each other by a joining portion such as sewing, and the main chamber 15 is formed into a bag shape by this joining.

[0022] At the central portion of the panel on the side opposite to the occupant 21, a gas introduction portion 23 is opened. The gas introduction portion 23 is opened in, for example, a circular shape in a range including the central portion of the panel 21 on the side opposite to the occupant. The interior of the main air chamber 15 and the interior of the conduit portion 16 communicate with each other via the gas introduction portion 23, and the configuration is such that the gas G is introduced into the main air chamber 15 through the conduit portion 16. In addition, the panel 21 on the side opposite to the occupant may be formed with an exhaust hole (vent hole) for releasing part of the gas G to properly maintain the internal pressure of the main air chamber 15 when restraining and protecting the occupant.

[0023] Then, inside the main air chamber 15, a reinforcing patch for reinforcement against the pressure of the gas G or the like, a tether for regulating the deployment behavior and shape, or the like may be arranged as necessary.

[0024] The conduit portion 16 is a portion into which the gas G directly flows from the inflator 12, and which causes the gas G to flow from the gas introduction portion 23 into the main air chamber 15. Further, the conduit portion 16 deploys forward, which is the side opposite to the occupant with respect to the rim portion 6 of the steering wheel 2, and is a portion that guides the main air chamber 15 from the front of the rim portion 6 of the steering wheel 2 to the rear of the rim portion 6 through the opening 8. The conduit portion 16 is formed into a bag shape or a tubular shape by one or a plurality of base fabrics. In the present embodiment, the conduit portion 16 is formed in an I-shaped tubular shape that extends longitudinally in the vertical direction, which is the first direction, in the inflated and deployed state. That is, the conduit portion 16 includes a lower surface portion 25 that is one end surface portion, a side surface portion 26 connected to the lower surface portion 25, and an upper surface portion 27 that is the other end surface portion connected to the side surface portion 26. The capacity of the conduit portion 16 is set to be smaller than that of the main air chamber 15.

[0025] The lower surface portion 25 is located at the lower end portion, which is the gas introduction side to the conduit portion 16, relative to the side surface portion 26. At the lower surface portion 25, that is, at the lower end portion of the conduit portion 16, an inflator insertion port 29 into which the inflator 12 is inserted is opened. The lower surface portion 25 is fixed together with the inflator 12 inserted into the inflator insertion port 29 to the bottom of the housing of the case body 10 via a mounting member such as a retainer.

[0026] The side portion 26 is the part that rises upward relative to the lower portion 25 when the airbag 11 or conduit portion 16 is inflated and deployed. The upper end side of the side portion 26, that is, the part on the upper portion 27 side, is the part that protrudes upward from the opening 23 relative to the case body 10 when the airbag 11 or conduit portion 16 is inflated and deployed. A communication hole is formed near the upper end of this side portion 26, and the gas introduction portion 23 of the main air chamber 15 is connected to this communication hole, and the anti-occupant side panel 21 of the main air chamber 15 is directly fixed to the rear of the side portion 26 by sewing or the like at a position around the communication hole and the gas introduction portion 23. In other words, the main air chamber 15 is adjacent to the rear side of the conduit portion 16. Therefore, the gas introduction portion 23 is open in a front-to-back direction that intersects or is perpendicular to the vertical direction in which the conduit portion 16 extends. Therefore, the gas inlet 23 is positioned so as not to directly face the inflator 12 in the vertical direction when the airbag 11 or conduit 16 is inflated and deployed.

[0027] The upper portion 27 is located at the upper end of the side portion 26, which is the end opposite to the gas introduction side to the conduit portion 16, and closes the upper end of the side portion 26. The upper portion 27, i.e., the upper end of the conduit portion 16, is located above the lower portion 25 and faces the lower portion 25 in the vertical direction when the airbag 11 or conduit portion 16 is inflated and deployed. Therefore, the upper portion 27 is located facing the inflator 12 in the vertical direction when the airbag 11 or conduit portion 16 is inflated and deployed. In addition, the upper portion 27 is located in a position that protrudes upward from the opening 13 relative to the case body 10 when the airbag 11 or conduit portion 16 is inflated and deployed. That is, the upper portion 27 is a protruding portion located in a position that protrudes forward relative to the main air chamber 15 when the airbag 11 or conduit portion 16 is inflated and deployed. The upper portion 27 has the same or substantially the same shape as the lower portion 25. In the illustrated example, the upper portion 27 and the lower portion 25 are formed in the shape of a circle, an oval, an ellipse, etc., respectively, but are not limited to these and may be polygonal shapes such as a quadrilateral.

[0028] The inflator 12 is electrically connected to a control device such as an on-board control unit (ECU) and is configured to inject gas G into the airbag 11 in response to a signal input when necessary, such as during a vehicle collision.

[0029] Then, the airbag 11 is fitted by inserting the inflator 12 and attaching it via the mounting member, then folded into a predetermined shape, and assembled to the case body 10 together with the inflator 12 via the mounting member.

[0030] For folding the airbag 11, the main air chamber 15 and the conduit section 16 are folded separately and independently. First, as shown in Figures 1(a) to 1(c), the main air chamber 15 is folded into a small rectangular prism-shaped fold 15a using a predetermined folding method. At this time, it is preferable that the main air chamber 15 be folded using any folding method that expands outward by the introduction of gas G, such as petal folding or compression folding. The folding of the main air chamber 15 may be done by machine or by hand. The fold 15a is held in its folded shape by an appropriate wrapping member 30 or the like.

[0031] Next, as shown in Figure 1(d), the upper surface portion 27 of the conduit portion 16 is folded over the folded mass 15a of the main air chamber 15 so as to overlap it on the upper side, that is, on the opposite side from the inflator 12 in the vertical direction, and then folded in an accordion (compression) fold from above to form the folded portion 16a. Then, as shown in Figure 1(e), the folded airbag 11 is attached to the housing of the case body 10 together with the inflator 12 and covered with a cover to form the airbag device 1. In this state, the airbag 11 has the main air chamber 15 located at the rear inside the case body 10, and the top, bottom, left, right, and front are covered by the conduit portions 16. The airbag device 1 configured in this way is assembled to the boss portion 5 of the handle 2.

[0032] When a collision impact occurs to the vehicle equipped with the airbag device 1, the control device activates the inflator 12. As shown in Figure 2, the inflator 12 rapidly injects gas G into the folded airbag 11, causing the conduit section 16 to expand upward and to the sides, raising the side sections 26. The upper part of the conduit section 16 applies upward pressure to the tearline of the case body 10, causing the tearline to rupture. The upper part of the conduit section 16 of the airbag 11, along with the folded mass 15a of the main air chamber 15, protrudes from the opening 13 to the outside of the case body 10, positioned in front of the rim section 6 (shown in Figure 4). In this state, the folded portion 16a overlaps the folded mass 15a in a bellows-like manner, and the expanding conduit section 16 is positioned at the front, thus restricting the upper and front parts of the folded mass 15a.

[0033] Then, as the gas in the conduit section 16 flows into the folded mass 15a of the main air chamber 15 via the gas introduction section 23, the folded mass 15a expands and unfolds. At this time, as shown in Figures 3(a) to 3(e), the folded mass 15a is pressed from above by the overlapping section 16a and pressed from front to rear by the expanded main body portion of the conduit section 16, so the unfolding direction of the folded mass 15a is restricted to the rear, i.e., towards the occupant, and as the bellows shape of the overlapping section 16a opens, the folded mass 15a is pushed out towards the occupant through the opening 8 (shown in Figure 4) of the rim portion 6 of the handle 2 and unfolds in the up, down, left, and right directions, and the main air chamber 15 faces the occupant side at the front of the handle 2, restraining and protecting the occupant who is thrown forward by the occupant side panel 20.

[0034] In this way, with the airbag 11 folded, the upper surface 27 of the conduit section 16 is folded back toward the main chamber 15, overlapping the folded mass 15a of the main chamber 15 on the opposite side of the inflator 12 in the vertical direction. As a result, the deployment direction of the main chamber 15 is restricted to a direction toward the occupant, intersecting the direction of gas introduction into the conduit section 16. Therefore, even in the driver's seat airbag device 1 used in the steering wheel 2, the main chamber 15 does not get stuck in the rim section 6 of the steering wheel 2, but deploys toward the occupant through the inside of the rim section 6, i.e., the opening 8. Consequently, the deployment behavior of the airbag 11 is stable, enabling rapid and optimal deployment behavior and occupant restraint.

[0035] Furthermore, since the folding shape of the conduit section 16 controls the unfolding behavior of the main air chamber 15, the folding shape of the folded mass 15a of the main air chamber 15 can be set to any desired shape.

[0036] In particular, in this embodiment, since the rim portion 6 is annular, by extending the conduit portion 16 forward of the rim portion 6 and passing the folded block 15a through the opening 8 of the rim portion 6, the folded block 15a comes into contact with the upper part of the rim portion 6, which is the 12 o'clock position on an analog clock. This allows it to be pressed by the folded portion 16a and the inner edge of the rim portion 6, thereby more reliably restricting the direction of deployment of the main air chamber 15.

[0037] Furthermore, since the folded portion 16a is folded in an accordion-like manner on top of the folded block 15a, it can be formed during a series of folding operations of the airbag 11, thereby simplifying the manufacturing process.

[0038] In one embodiment, the airbag device 1 was given as an example for the driver's seat, but it is not limited to this and may be applied to the passenger seat, etc. [Industrial applicability]

[0039] The present invention can be suitably used, for example, in an airbag system for the driver's seat of an automobile. [Explanation of symbols]

[0040] 2 handles 6. Rim section 11 Airbags 12 Inflators 15 Main air chamber 15a folded block 16 Conduit section 23 Gas inlet 27. Upper surface portion which is a protruding part G Gas

Claims

1. An airbag comprising a main chamber having a gas inlet, and a conduit for allowing gas from an inflator to flow from the gas inlet into the main chamber, The gas introduction section is opened in a second direction that intersects with the first direction in which the conduit section extends. The conduit portion has a projection that protrudes in the second direction relative to the main air chamber, In the folded state, the protruding portion of the conduit is folded back toward the main air chamber and superimposed on the folded mass of the main air chamber on the side opposite to the inflator in the first direction. An airbag characterized by the following features.

2. It is an airbag mounted on the steering wheel of the vehicle, with the main air chamber deploying in front of the occupant. The airbag according to claim 1, characterized in that it is a feature of the airbag.

3. The conduit section extends to the side of the steering wheel rim away from the occupant. The main air chamber extends from the inside of the rim towards the occupant side relative to the rim. The airbag according to claim 2, characterized in that it is as described above.

4. The protruding portion of the conduit is folded back towards the main chamber and is folded in an accordion-like manner in the first direction relative to the folded mass of the main chamber, on the side opposite to the inflator. An airbag according to any one of claims 1 to 3, characterized in that it is as described above.

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