airbag

Abstract

To provide an airbag that can achieve stable deployment behavior. [Solution] The airbag 11 is mounted on the steering wheel 2 for steering the vehicle. The airbag 11 comprises a main air chamber 15 and a conduit portion 16 that allows gas G from the inflator 12 to flow into the main air chamber 15. The conduit portion 16 has a side portion 26 facing the main air chamber 15 and a lower portion 25 which is formed separately from the side portion 26 and is an end portion located at least at the end of the side portion 25 on the inflator 12 side. In the inflated and deployed state, the main air chamber 15 and the conduit portion 16 are positioned with the rim portion 6 of the steering wheel 2 in between.

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 apparatus 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 inflated from the opening is deployed toward the 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 a main air chamber for occupant protection into which gas is introduced through the conduit portion, and is configured to properly protect the occupant even if the gas introduction direction to the airbag is not the occupant direction (see, for example, 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 above configuration, since the conduit portion is bent in an L-shape along the opening inside the rim portion of the steering wheel, the conduit portion is pulled in the occupant direction as the main air chamber inflates and deploys. Therefore, it is desirable to prevent the expansion and contraction of the conduit portion caused by such pulling from hindering the stable deployment behavior of the airbag.

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

Means for Solving the Problems

[0006] An airbag according to an aspect of the present invention is an airbag mounted on a steering wheel for a vehicle, comprising a main chamber and a conduit portion for allowing gas from an inflator to flow into the main chamber, wherein the conduit portion has a side portion facing the main chamber and an end portion formed separately from the side portion and located at least at the end of the side portion on the inflator side, and in the inflated and deployed state, the main chamber and the conduit portion are positioned on either side of the rim portion of the steering wheel. [Effects of the Invention]

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

[0008] [Figure 1] This is a schematic cross-sectional view showing an airbag according to the first embodiment of the present invention. [Figure 2] This is a front view showing a steering wheel equipped with the same airbag. [Figure 3] This is a cross-sectional view of the connection between the main air chamber and the conduit section of the same airbag. [Figure 4] This is an exploded plan view of the conduit section of the airbag shown above. [Figure 5] This is a side view showing the inflated and deployed state of the airbag. [Figure 6] This is an exploded plan view of the conduit section of the airbag according to a second embodiment of the present invention. [Figure 7] This is an exploded plan view of the conduit section of the airbag according to the third embodiment of the present invention. [Figure 8] This is an exploded plan view of the conduit section of the airbag according to the fourth embodiment of the present invention. [Modes for carrying out the invention]

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

[0010] In Figures 1 and 2, 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] Then, the airbag device 1 constitutes the front side of the boss portion 5 of the steering wheel 2. The airbag device 1 includes a case body 10, and the case body 10 accommodates and is configured with an airbag 11, an inflator 12 which is a gas generation device that supplies gas G to the airbag 11, and the like. In the event of a vehicle collision or the like, the airbag 11 is inflated by the introduced gas G, deploys from the case body 10 to the front side of the steering wheel 2, and protects the occupant, who is the protection target, 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. With respect to the housing mounted on the core metal of the boss portion 5, the airbag 11 is stored in a folded state, and the inflator 12 is attached. The cover is a portion facing the front of the occupant. The cover may be provided with an operation panel operated by the occupant, a display unit, and the like.

[0016] A tear line serving as a planned fracture portion is formed in the case body 10. The planned fracture portion is configured to maintain the required strength of the case body 10 during normal times, and to be fractured by the inflation pressure of the airbag 11 in an emergency such as a crisis, so as to form an opening 13 in the case body 10 for the airbag 11 to protrude. For example, the tear line is formed in a groove shape on the inner surface side of the cover or the housing of the case body 10, making the corresponding portion of the cover or the housing a thin-walled portion. In the present embodiment, the tear line is formed in the upper part of the case body 10 in front of the rim portion 6 of the steering wheel 2. For example, the tear line is formed in an H shape, a U shape, or the like, and extends in the front-rear direction and the left-right direction.

[0017] The airbag 11 is formed in a bag shape that is inflated when gas G is introduced. The airbag 11 is folded small into a predetermined folded shape and stored inside the case body 10, and is inflated and deployed by the 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 the up, down, left, and 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] The main chamber 15 is provided with an occupant-side panel 20 located on the occupant side, that is, the rear side in the inflated state, and an anti-occupant-side panel 21 located on the opposite side, that is, the steering wheel 2 side, the front side.

[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 anti-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 anti-occupant-side panel 21 are each formed in a circular shape when viewed from the front. The occupant-side panel 20 and the anti-occupant-side panel 21 are each composed of one or a plurality of base fabrics. At least one of the occupant-side panel 20 and the anti-occupant-side panel 21 may have a reinforcing panel such as a reinforcing fabric 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 anti-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] A gas inlet 23 is opened in the center of the anti-occupant side panel 21. The gas inlet 23 is opened, for example, in a circular shape, in an area including the center of the anti-occupant side panel 21. The inside of the main air chamber 15 and the inside of the conduit 16 are in communication through the gas inlet 23, and gas G is introduced into the main air chamber 15 through the conduit 16. In addition, the anti-occupant side panel 21 may have exhaust holes (vent holes) to release some of the gas G and maintain an appropriate internal pressure in the main air chamber 15 when the occupant is restrained.

[0023] Furthermore, reinforcing patches for protection against gas G pressure, tethers for restricting deployment behavior and shape, etc., may be placed inside the main chamber 15 as needed.

[0024] The conduit section 16 is the part through which gas G flows directly from the inflator 12 and into the main air chamber 15 from the gas inlet section 23. The conduit section 16 also extends forward of the rim 6 of the handle 2, on the side opposite to the occupant, and guides the main air chamber 15 from the front of the rim 6 of the handle 2 through the opening 8 to the rear of the rim 6. The conduit section 16 is formed in a bag-like or cylindrical shape from one or more base fabrics. In this embodiment, the conduit section 16 is formed in an I-shaped cylindrical shape that extends longitudinally in the vertical direction, which is the first direction toward the rim 6 of the handle 2 when inflated and deployed. That is, the conduit section 16 comprises a lower surface section 25, which is one end surface section, a side surface section 26 connected to the lower surface section 25, and an upper surface section 27, which is another end surface section connected to the side surface section 26. The capacity of the conduit section 16 is set to be smaller than that of the main air chamber 15.

[0025] The lower portion 25 is located at the lower end of the conduit portion 16, on the gas introduction side, relative to the side portion 26. An inflator insertion port 29 into which the inflator 12 is inserted is opened at the lower portion 25, i.e., the lower end of the conduit portion 16. The lower portion 25, together with the inflator 12 inserted into the inflator insertion port 29, is fixed to the bottom of the housing of the case body 10 via mounting members such as retainers. As shown in Figure 4, mounting holes 30 for inserting mounting bolts for mounting members are formed around the periphery of the inflator insertion port 29.

[0026] The side portion 26 shown in Figure 1 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 32 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 32. As shown in Figure 3, the anti-occupant side panel 21 of the main air chamber 15 is directly fixed to the rear of the side portion 26 by a joint 33 such as sewing at a position around the communication hole 32 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 communication hole 32 and the gas introduction portion 23 open in a front-to-back direction that intersects or is perpendicular to the vertical direction in which the conduit portion 16 extends. Therefore, as shown in Figure 1, the communication hole 32 and the gas introduction section 23 are located in positions that do not directly face the inflator 12 in the vertical direction when the airbag 11 or the conduit section 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 both elongated ovals, longer in the front-to-back direction and shorter in the left-to-right direction.

[0028] The conduit section 16 consists of multiple, preferably three or more, parts (members). In this embodiment, the lower section 25, the side section 26, and the upper section 27 are each formed from separate members, for example, separate base fabrics. The lower section 25, the side section 26, and the upper section 27 each consist of at least one member, and in the example shown in Figure 4, they are formed from single base fabrics 25a, 26a, and 27a. That is, in this embodiment, the base fabrics 25a and 27a are oval in shape, and the base fabric 26a is rectangular in shape with the outer circumference of the base fabrics 25a and 27a as its longitudinal dimension. Note that each of the base fabrics 25a, 26a, and 27a may be composed of multiple pieces of the same or different types, overlapping all or partially.

[0029] As shown in Figure 1, 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.

[0030] 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.

[0031] When a collision impact occurs to a vehicle equipped with the airbag device 1, the control device activates the inflator 12, and gas G is rapidly injected into the folded airbag 11 by the inflator 12. As shown in Figure 5, the conduit portion 16 expands upward and to the left and right, causing the side portions 26 to rise. The upper part of the conduit portion 16 applies upward pressure to the tear line of the case body 10, causing the tear line to rupture, and the upper part of the conduit portion 16 of the airbag 11 protrudes from the opening 13 to the outside of the case body 10 and is positioned in front of the rim portion 6.

[0032] In this state, the upper surface portion 25 of the conduit portion 16 extends beyond the rim portion 6, that is, it is above the 12 o'clock position which is the upper end of the rim portion 6, and bulges upward in a convex shape, so that the rear part of the side portion 26 on the upper end side faces the front part of the rim portion 6. The communication hole 32 and the gas introduction portion 23 are located on the opposite side of the upper surface portion 25 with respect to the upper end of the rim portion 6, that is, below the upper end of the rim portion 6. As a result, as the gas in the conduit portion 16 flows into the folded mass of the main air chamber 15 through the communication hole 32 and the gas introduction portion 23, this folded mass is pushed out toward the occupant through the opening 8 of the rim portion 6 of the handle 2 and expands in the up, down, left, and right directions. At this time, the conduit portion 16 catches on the upper end of the rim portion 6, and its rearward movement is restricted by the rim portion 6, thereby preventing the conduit portion 16 from being pulled backward by the movement of the folded mass of the main gas chamber 15 due to the inflow of gas G or the pressure of the expansion and unfolding of the main gas chamber 15.

[0033] The main air chamber 15 is positioned in front of the steering wheel 2 and faces the occupant, and the airbag 11 is held in a position where the main air chamber 15 and the conduit section 16 sandwich the upper end of the rim section 6 from front to back, that is, in contact with the rim section 6 from front to back, and the occupant side panel 20 restrains and protects the occupant who is thrown forward.

[0034] Thus, by forming the conduit section 16 with a side portion 26 facing the main air chamber 15 and a lower portion 25 which is a separate end portion from the side portion 26 located at least at the end of the side portion 26 on the inflator 12 side, the strength of the base fabric 26a and base fabric 25a and the strength of the stitching can be changed in the conduit section 15 between the side portion 26 and the lower portion 25. This provides a high degree of freedom in tuning the strength of the conduit section 16, and not only can breakage of joints such as stitching and stretching of the base fabrics 25a, 26a, etc. be suppressed, but in the inflated and deployed state, the main air chamber 15 and the conduit section 16 are positioned with the rim portion 6 of the handle 2 in between, so even if the conduit section 16 tries to be pulled backward by the inflation and deployment of the main air chamber 15, the rear of the conduit section 16 is restricted by contact with the rim portion 6, thereby suppressing backward movement. Therefore, the airbag 11 is prevented from swinging back and forth due to the conduit section 16 being pulled back and forth, the deployment behavior of the airbag 11 is stabilized, and a rapid and suitable deployment behavior and occupant restraint can be achieved.

[0035] Furthermore, since the conduit section 16 has an end surface, the lower surface 25, and the upper surface 27 at both ends of the side surface 26, the number of parts constituting the conduit section 16 can be increased. This increases the degree of freedom in tuning the strength of the conduit section 16, and suppresses breakage of joints such as sewing and elongation of the base fabric 25a to 27a, thereby making the deployment behavior of the airbag 11 more stable. In addition, since each part can be reinforced, reinforcement can be concentrated only on the necessary parts compared to reinforcing the entire airbag 11, preventing increased costs caused by reinforcing unnecessary parts.

[0036] In particular, since the conduit section 16 has a smaller capacity than the main air chamber 15, the pressure is higher, which makes it more prone to rupture of materials such as the base fabric and joints such as their stitching, as well as significant stretching of materials such as the base fabric. By increasing the degree of freedom in tuning the strength of the conduit section 16, the stretching of the base fabric 25a to 27a can be suppressed, and the deployment behavior of the airbag 11 can be effectively stabilized.

[0037] By forming a communication hole 32 in the side portion 26 that connects the inside of the conduit portion 16 and the inside of the main air chamber 15, it becomes possible to directly join the conduit portion 16 and the main air chamber 15, and the amount of stretching of the base fabric due to the expansion and deployment of the main air chamber 15 can be reduced, thereby further suppressing the oscillation of the airbag 11.

[0038] Furthermore, when gas G is introduced from the inflator 12, the conduit portion 16 that protrudes upward toward the rim portion 6 of the handle 2 has its upper surface portion 27 positioned beyond the rim portion 6 when inflated and deployed. Therefore, even if the conduit portion 16 is pulled backward by the expansion and deployment of the main air chamber 15, the rear of the conduit portion 16 is reliably restricted by contact with the rim portion 6, thereby reliably suppressing the backward movement of the conduit portion 16. In addition, since the communication hole 32 is located on the lower side, opposite to the upper surface portion 27 with respect to the rim portion 6, the main air chamber 15 is less likely to get caught on the rim portion 6 during expansion and deployment, enabling smoother deployment.

[0039] In the first embodiment, the conduit portion 16 only needs to have a lower portion 25, a side portion 26, and an upper portion 27 that are independent parts of each other, and the lower portion 25 and the upper portion 27 are not limited. For example, in the first embodiment, the lower portion 25 and the upper portion 27 are each oval in shape, but are not limited to this, and may be circular in shape, as in the second embodiment shown in Figure 6, or square in shape, as in the third embodiment shown in Figure 7, or they may be elliptical or polygonal in shape, etc. Also, the side portion 26 is not limited to being made of a single base fabric 26a, but may be made of multiple members, such as two members, a base fabric 26a in which the communication hole 32 is formed and another base fabric 26b, as in the fourth embodiment shown in Figure 8. [Industrial applicability]

[0040] The present invention can be suitably used, for example, as an airbag system for the driver's seat of an automobile. [Explanation of symbols]

[0041] 2 handles 6. Rim section 11 Airbags 12 Inflators 15 Main air chamber 16 Conduit section 25 End face portion, which is the lower surface portion 26 Side part 27. Upper surface which is the end face 32 Communication hole G Gas

Claims

1. An airbag mounted on the steering wheel for vehicle steering, The main chamber and, It comprises a conduit section for allowing gas from the inflator to flow into the main air chamber, The aforementioned conduit section is The side portion facing the main air chamber, This side portion is formed separately from this side portion and has an end portion located at least at the end of this side portion on the inflator side, In the expanded and deployed state, the main air chamber and the conduit section are positioned with the rim of the handle in between. An airbag characterized by the following features.

2. The end faces are located at both ends of the side faces. The airbag according to claim 1, characterized in that it is a feature of the airbag.

3. A connecting hole is formed on the side of the conduit section, linking the inside of the conduit section to the inside of the main air chamber. The airbag according to claim 1 or 2, characterized in that it is as described above.

4. The end faces are located at both ends of the side faces, The conduit section protrudes toward the rim of the handle due to the introduction of gas from the inflator, and in the inflated and deployed state, one of the aforementioned end faces is positioned beyond the rim, and the communication hole is located on the opposite side of the rim from the aforementioned end face. The airbag according to claim 3, characterized in that it is as described above.

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