JP4254001B2 - Steering wheel airbag - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an airbag for a steering wheel in an automobile. In particular, the invention relates to an airbag for a steering wheel that is excellent in invasion characteristics between the driver (occupant) and the steering wheel in the early stage of deployment of the airbag.
[0002]
[Background]
In order to protect the passengers accurately in the steering wheel airbag device, the airbag is quickly deployed and inflated at the initial stage of the bag deployment (immediately after the bag launches), and the steering wheel (hereinafter referred to as “wheel”). ) And the occupant must be quickly invaded. Usually, the distance L1 between the lower part of the ring part (rim part) 16 of the steering wheel 12 and the abdomen of the occupant body 14 is the distance from the other part of the ring part 16, that is, the distance L2 at the upper part and the distance L3 at both sides. It is shorter (see FIGS. 1 and 2). For this reason, the penetration | invasion between the passenger | crew abdomen and a ring part of the bag in the initial stage of deployment (Hereinafter, it may describe as "bag penetration | invasion between a passenger | crew abdomen / ring part.") Is easy to be inhibited. In particular, when the occupant is setting the seat (seat) position forward, this tendency becomes more prominent.
[0003]
For this reason, as techniques for facilitating bag entry between the occupant abdomen / ring part, various techniques described below using a rectifying cloth have been proposed.
[0004]
JP-A-1-311930, JP-A-8-104196, JP-A-9-30353, JP-A-9-118185, JP-A-9-220995, JP-A-10-1000083, JP-A-10-152009, Patent No. 2,677,937, International Patent Publication No. WO97 / 36768, British Patent Specification GB-2331409-A, etc. These techniques using the rectifying cloth basically move the rectifying cloth up and down so as to substantially cover the surface facing the rear panel of the inflator. It is the structure which is arranged in the direction and guides (guides) the gas flow ejected from the inflator with the rectifying cloth in the circumferential direction of the airbag.
[0005]
However, the gas ejected from the inflator flows mainly in the left-right direction, and flows in the vertical direction along the left and right edges of the rectifying cloth, that is, in the direction parallel to the vertical center line of the airbag. The flow toward the center line becomes weaker.
[0006]
In combination with the small distance (gap) between the occupant's abdomen and the ring part and the weakness of the flow toward the center line in the vertical direction of the wheel, the conventional rectifying cloth technology allows the airbag to be used when the airbag is deployed and inflated. The bag invasion action toward the center line in the vertical direction of the wheel, especially between the occupant's abdomen / ring part, was weak.
[0007]
In view of the above, the present invention provides an airbag for a steering wheel that can be expected to increase the action toward the center line of the airbag wheel in the vertical direction, in particular, to increase the bag intrusion action between the abdomen / ring part of the occupant. Objective.
[0008]
[Means for Solving the Problems]
As a result of diligent efforts to achieve the above-mentioned problems, the present inventors have come up with a steering wheel airbag having the following configuration.
[0009]
An airbag assembled from an airbag device for a steering wheel and formed from a panel (base fabric),
Viewed from the occupant side at the time of deployment bulging completed (hereinafter, "top and bottom, the right and left-front and rear" are based on this.) Plan outer peripheral shape is substantially circular bag,
In an airbag comprising a bag main body comprising a front panel provided with a gas inlet, a rear panel facing the front panel, and a rectifying cloth body disposed in the bag main body facing the gas inlet. ,
Flow regulating cloth body, a pair of left and right radial passage extending to the outer peripheral edge of the bag body branches into the left and right sides from the gas inlet, along the periphery of the bag body from the tip of the left and right radial passage A pair of left and right circumferential flow paths are provided that extend vertically and have upper and lower opening ends at positions where gas can flow out toward the vertical center line of the bag body ,
And the rear panel is widened upward,
In the expanded and inflated state, the shape of the panel is set so that the longitudinal cross-sectional shape of the bag body is thicker than the lower side across the gas inlet .
[0010]
The airbag having this configuration is used by being incorporated in an airbag device and mounted on a steering wheel. When the airbag apparatus is activated, the inflation gas ejected from the gas ejection port of the inflator flows into the airbag from the gas inlet and expands and inflates the airbag. The inflation gas reaches the periphery of the bag body while bulging the left and right radial flow paths formed by the rectifying cloth body, and then ejects from the upper and lower opening ends via the left and right circumferential flow paths. At this time, since each open end is in a position where gas can flow out toward the vertical center line of the bag, a vector gas flow toward the vertical center line is generated in the airbag, resulting in the occupant's head. The airbag quickly deploys between the body and abdomen and the steering wheel. For this reason, the increase of the bag penetration | invasion effect | action between a passenger | crew's abdomen / ring part can be anticipated.
[0011]
And since the bag body is set so that the rear panel is widened upward and the rear panel is expanded and inflated, the longitudinal cross-sectional shape is thicker on the upper side than on the lower side . When the airbag is deployed and inflated, the airbag expands to a thickness corresponding to the distance between the occupant's body and the ring part, so that the resistance when entering the gap between the occupant's body and the ring is reduced, and the occupant's abdomen and This is because the air bag easily enters between the ring portion (the bag intrusion action between the occupant abdomen and the ring portion increases).
[0012]
Furthermore, in the configuration in which the upper side of the bag body in the expanded and inflated state is thickened, it is desirable that the opening diameter at the upper opening end is larger than the opening diameter at the lower opening end. This is because it becomes easy to secure the amount of inflation gas corresponding to the inflation capacities on the upper and lower sides of the airbag, and the airbag is more smoothly deployed and inflated.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
The airbag 12 of this embodiment is assembled to the steering wheel airbag apparatus M.
[0014]
The airbag 18 is viewed from the occupant side at the time of completion of deployment (hereinafter, unless otherwise specified, “up / down / left / right / front / rear” is used as a reference). A bag body 26 having a front panel 22 having a gas inlet 20 (which serves as an attachment port for the inflator 21), a rear panel 24 facing the front panel 22, and a gas in the bag body 26. It is the structure provided with the baffle cloth body 28 arrange | positioned facing the inflow port 20. FIG.
[0015]
Regulating cloth body 28, the bag body 26 is branched to the left and right sides from the gas inlet 20 (typically, front panel 22) and a pair of left and right radial passage 30, 32 extending to the outer periphery of the left and right radial The upper and lower open ends 34 and 36 are provided at positions where gas flows out toward the vertical center line C of the bag body 26 from the front ends of the directional flow passages 30 and 32 along the periphery of the bag body 26. A pair of left and right circumferential flow paths 38 and 40 are formed. The total flow volume of the left and right radial flow paths 30 and 32 and the left and right circumferential flow paths 38 and 40 at this time varies depending on the required development characteristics of the bag body 26. Usually, it sets so that it may become 1/50-1/5 of the full capacity of the bag main body 26 at the time of completion of expansion. If the flow path capacity is too small, gas flow resistance is generated in the flow path, and the amount of gas inflow per hour into the bag body 26 is reduced, so that the upper and lower parts (head position and abdominal position) of the bag body 26 There is a risk that deployment and expansion will be delayed. On the contrary, even if the flow path capacity is too large, it takes time for the gas to accumulate in the left and right circumferential flow paths 38 and 40, and it takes time until the gas flows into the bag body 26. There is a risk that the expansion and expansion will be delayed in the upper and lower portions (head position and abdominal position) in FIG.
[0016]
Here, the positions of the upper and lower opening ends 34 and 36 are α and β = 120 to 30 °, preferably 90 to 60 °, where α and β are the angles across the vertical center line C, respectively. . In particular, when aiming to increase the bag invasion action between the occupant abdomen / ring part, the lower angle β is made smaller than the upper angle α. If these angles α and β (particularly the lower angle β) are too large, the action (vector) of the gas flow from the upper and lower opening ends 34 and 36 toward the vertical center line C becomes weak, and the effect of the present invention is achieved. (In particular, the bag invasion action between the occupant abdomen / ring part) may not be sufficiently achieved.
[0017]
In addition, the left and right radial flow paths 30 and 32 extend in the horizontal direction (left and right direction) in the illustrated example. You may make it the distance from the terminal (branch site | part) of the flow paths 30 and 32 to the lower opening end 36 shorter than the upper opening end 34. FIG. In this case, it can be expected that the bag intrusion between the occupant's abdomen / ring part will be performed quickly, with the lower expansion and expansion of the bag body 26 taking priority over the upper one. The opening angle (inner angle) at this time is 60 ° to 180 °.
[0018]
In the present embodiment, the portion facing the gas inlet 20 by the rectifying cloth body 28 has an inner bag 29 configuration. This is to quickly eject the airbag.
[0019]
Further, in the present embodiment, as shown in FIG. 4, the bag body 26 has a panel (base fabric) so that the longitudinal cross-sectional shape is thicker than the lower side across the gas inlet when deployed and inflated. In other words, the shapes of the front and rear panels 22 and 24 are set in the illustrated example. When the airbag is deployed and inflated, the airbag is inflated to a thickness corresponding to the distance between the upper and lower parts of the occupant body 14 and the ring portion 16, so that resistance when entering the gap between the occupant body 14 and the ring portion 16 is reduced. This is because the airbag easily enters between the occupant abdomen 14a and the ring part 16.
[0020]
As a form in which the upper side of the expanded and expanded shape is thicker than the lower side, the rear panel 24 is usually made wider toward the top as shown in FIG. Other, or allowed to localize the gas inlet 20 to the lower side, further, between the front panel 22 and rear panel 24, the Obipa panel of the distal tapered in the middle wide, so that the center side is on top (upper side) Various embodiments are conceivable.
[0021]
The opening diameter d1 of the upper end opening 34 is larger than d2 in the lower end opening 36. This is because it is easy to secure the amount of inflation gas corresponding to the upper and lower inflation capacities of the airbag body 26, and the airbag body 26 can be deployed and inflated more smoothly. The ratio of the opening diameters at this time is d1 / d2 = 3/1 to 1/1.
[0022]
The airbag 18 of the present embodiment is usually manufactured by stitching a woven fabric made of polyester yarn or nylon yarn into panel bodies (base fabrics) 22, 24, 28 cut into a predetermined shape (FIG. 5). See also), and can also be produced by bonding or bag sewing. The panel body may be a woven fabric rubberized.
[0023]
That is, as shown in FIG. 3 (or FIG. 5), the rectifying panel 28 has the curved H-shaped panel 28 sewn directly to the front panel 22 (the side provided with the gas inlet 20), and the left and right radial directions. The flow paths 30 and 32 and the left and right circumferential flow paths 38 and 40 are formed.
[0024]
The bag body 26 is formed by inverting the front panel 22 (bottom side panel) and the rear panel 24 (ceiling side panel), to which the rectifying panel 28 is stitched, with the inner side facing outward, and then inverted. The front panel 22 is usually provided with one or more vent holes (vents) 23 (two on the left and right in the example). The peripheral edges of the gas inlet 20 and the gas vent hole 23 are not shown, but are usually reinforced by sewing together one or more annular reinforcing cloths.
[0025]
Next, the usage aspect of the airbag of this embodiment is demonstrated.
[0026]
The airbag apparatus A for a steering wheel to which the airbag is applied will be described by taking as an example a case where it is mounted on a three-spoke type wheel body 46 as shown in FIG. 6, for example. Four-spoke type, two-spoke The same applies to the type.
[0027]
The wheel body 46 includes a ring portion 16 that is gripped during steering, a boss portion 50 that is connected to a steering shaft (not shown), three spoke portions 52 that connect the boss portion 50 and the ring portion 16, and extend in the left-right and downward directions. 52 and 54.
[0028]
The wheel main body 46 is configured by covering a wheel metal core 56 made of aluminum die casting or the like with a molding covering portion 58 of a synthetic resin such as polyurethane. Further, an airbag device A and a horn switch device S are incorporated in the wheel body 46 (see FIGS. 7 and 8). The outline is as follows.
[0029]
In the airbag device A, the inflator 62, the airbag 18, and the pad cover 66 are integrated through a device case 68. The air bag device A is attached to the horn switch device at three locations between the support flange 70a of the support plate 70 screwed to each of the spoke cores 56a of the wheel core 56 and the mounting flange 68a of the device case 68. S is arranged and supported by three points. Since the switch device S is a conventional device in which a coil spring 76 is disposed between the fixed contact 72 fixed to the support flange 70a and the movable contact 74 fixed to the mounting flange 68a, detailed description thereof is omitted. Reference numeral 78 denotes a guide post (stepped bolt) for moving the movable contact in the vertical direction, and reference numeral 80 denotes a pressing rib.
[0030]
Thus, the steering wheel W incorporating the airbag device or the like is mounted on the vehicle by being incorporated into the steering device via a steering shaft (not shown).
[0031]
An impact load detection signal is input to the inflator 62, and the inflation gas ejected from the inflator 62 flows into the airbag 18 from the gas inlet 20. Then, the inner bag 29 formed at the center of the rectifying panel 28 is first inflated to break and open the H-shaped tear line 67 of the pad cover 66 to form an air outlet. Thereafter, the airbag 18 jumps out of the device case 68 and expands and inflates.
[0032]
In the airbag 18 of the present embodiment, the following gas flow is generated due to the presence of the rectifying panel 28 disposed in the bag body 26.
[0033]
First, the inflation gas is ejected in the left-right direction of the bag and collides with the periphery of the bag body 26 while inflating the left and right radial flow paths 30 and 32 formed by the rectifying panel 28. The gas that collides with the peripheral edge of the bag body 26 is divided vertically along the peripheral edge of the bag body 26 by the left and right circumferential flow paths 38 and 40, and then flows out from the upper and lower opening ends 34 and 36. Since the positions of the upper and lower opening ends 34 and 36 are at positions where the gas flow is directed to the vertical center line C of the bag body (wheel) 26, the inflation gas flows in the vertical center line direction of the bag. The expansion direction is toward the vertical center of the wheel W. For this reason, the airbag quickly expands and bulges on the abdomen 14a side and the head 14b side of the occupant body 14 from the direction in which the gap between the ring part 16 and the occupant body 14 exists. At this time, even if the distance of the vertical center line C part between the lower part of the ring part 6 and the abdomen 14a of the occupant body is shorter than the other parts, the gas flow has a vector toward the center line. Therefore, the airbag 18 can quickly enter between the occupant abdomen 14 a and the ring part 16 from the direction in which there is a gap between the ring part 16 and the occupant body 14. And in this embodiment, since the expansion | swelling form of the bag main body 26 is the structure which made the upper side thick and made the lower side thin, even if the space between the lower end part of the ring part 16 and the passenger | crew body 14 is adjoining, the bag main body 26 Therefore, the invasion resistance is small, and the invasion of the airbag 18 between the occupant abdomen 14a / ring part 16 due to the expansion and inflation is smooth.
[0034]
【The invention's effect】
As described above, the airbag of the present invention is provided with a bag body having a front panel provided with a gas inlet and a rear panel facing the front panel, and disposed in the bag body facing the gas inlet. In the airbag including the rectifying cloth body, a pair of left and right radial flow paths branching from the gas inflow port to the left and right sides and extending to the outer peripheral edge of the bag body, and the radial flow path A pair of left and right circumferential flow paths are formed that extend vertically from the tip along the periphery of the bag body and have upper and lower opening ends at positions where gas can flow out toward the center line in the vertical direction of the bag body. Due to the above-described structure, an increase in the action toward the center line in the vertical direction of the airbag wheel (bag intrusion action between the occupant's abdomen / ring part) can be expected due to the above-described action.
[0035]
In the above configuration, when the shape of the panel is set so that the longitudinal cross-sectional shape of the bag body is thicker than the lower side in the deployed and inflated state, the bag body is between the occupant abdomen and the ring part. The air bag easily enters.
[0036]
Furthermore, in the configuration in which the upper side of the bag body in the expanded and inflated state is thickened, when the opening diameter at the upper opening end is larger than the opening diameter at the lower opening end, the airbag is more smoothly expanded and expanded.
[Brief description of the drawings]
FIG. 1 is a model diagram showing a vertical positional relationship between an occupant (driver) and a steering wheel. FIG. 2 is a model diagram showing a horizontal positional relationship. FIG. 3 is an airbag according to an embodiment of the present invention. Fig. 4 is a plan view of the front panel as viewed from the inside. Fig. 4 is a cross-sectional view of the model in the state where the airbag is inflated along the line 4-4 (center line in the vertical direction) in Fig. 3; Figure (including inflator)
6 is a plan view showing an example of a steering wheel incorporating the airbag of the present invention. FIG. 7 is a schematic cross-sectional view taken along line 7-7 of FIG. 6. FIG. 8-8 schematic cross-sectional view of FIG. 6 [Explanation of symbols]
12 Steering wheel 14 Crew body (driver body)
16 Ring part (rim part)
18 Airbag 20 Gas inlet 21 Inflator 22 Front panel (bottom panel)
24 Rear panel (ceiling panel)
26 Bag body 28 Rectification panel 30 Left radial flow path 32 Right radial flow path 34 Upper opening end 36 Lower opening end 38 Left circumferential flow path 40 Right circumferential flow path C Vertical center line of bag (ring part)

Claims (2)

An airbag assembled from a steering wheel airbag device and formed from a panel (base fabric),
Viewed from the occupant side at the time of deployment bulging completed (hereinafter, "top and bottom, the right and left-front and rear" are based on this.) Plan outer peripheral shape is substantially circular bag,
Airbag having a front panel provided with a gas flow inlet, the bag body comprising a rear panel opposed to the front panel, and a current regulating cloth body disposed facing the said gas inlet into said bag body In
The flow regulating cloth body, the left and right radial passage pair of extending to the outer peripheral edge of the bag body branches into the left and right sides from the gas inlet, the bag body from the tip of the left and right radial passage A pair of left and right circumferential flow paths are provided that extend up and down along the periphery and have upper and lower opening ends at positions where gas can flow out toward the vertical center line of the bag body, respectively. and,
The rear panel is widened upward,
For a steering wheel, wherein the bag body has a panel shape set such that, in a deployed and inflated state, the longitudinal cross-sectional shape is thicker than the lower side across the gas inlet Airbag. The steering wheel airbag according to claim 1, wherein an opening diameter at the upper opening end is larger than an opening diameter at the lower opening end.

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