The present invention relates to a side airbag apparatus that, when an impact is applied from the exterior of a vehicle, inflates and deploys an airbag between a body side portion of the vehicle and an occupant seated on a vehicle seat to restrain the occupant with the airbag, thereby protecting the occupant from the impact.
For example, Domestic re-publication of PCT international application No. 2002-100691 discloses a side airbag apparatus. This apparatus protects an occupant seated on a seat from an impact due to a side collision that is applied to a side portion of the vehicle body such as a side door. In this apparatus, when an impact is applied to the body side portion from the exterior, an inflator discharges inflation gas into an airbag. The airbag is referred to as a flat bag. The airbag is formed by stacking a connected pair of base fabric sheets or a pair of independent fabric sheets, and joining the peripheral portions. When inflation gas is supplied into the airbag, the airbag pops out of a seat back (backrest portion) and is inflated and deployed in a narrow space between the occupant and the body side portion. The inflated airbag restrains the occupant and reduces the impact applied to the occupant from the exterior via the body side portion.
In the side airbag apparatus disclosed in Domestic re-publication of PCT international application No. 2002-100691, sewing is performed with the front end and the rear end of the bottom of the airbag being pinched. At the inflation and deployment of the airbag, a portion of the airbag between the sewn portions is located directly above the seat cushion (seat portion). The airbag is inflated so as to have a flat shape substantially parallel to the seating face of the seat cushion. Thus, the airbag is inflated with a larger thickness along the widthwise direction of the vehicle (lateral direction) in a section that corresponds to the lumbar region of the occupant, that is, in a section in the vicinity of the seating face of the seat cushion. This enhances the occupant restraining performance of the airbag.
However, according to the configuration of the above document, the bottom of the airbag is flat in a large area and its thickness along the lateral direction is great in the vicinity of the seating face of the seat cushion. Therefore, the bottom of the airbag cannot easily enter the narrow space between the lumbar region of the occupant and the body side portion.
Such a drawback is particularly disadvantageous in the case where a flat airbag is used. If the number of base fabric sheets is increased so that the airbag has a three-dimensional structure, the airbag can be inflated and deployed into a desired shape and the above described drawback is eliminated. However, the manufacture of three-dimensional airbags is complicated compared to that of flat airbags. Further, an airbag is stored in a seat back in a folded state. In this regard, a three-dimensional airbag is harder to fold than a flat airbag. Therefore, the manufacturing costs of a three-dimensional airbag are higher than those of a flat airbag.
Accordingly, it is an objective of the present invention to improve the deployment performance of a side airbag apparatus using a flat airbag, while ensuring the restraining performance.
To achieve the foregoing objective and in accordance with one aspect of the present invention, a side airbag apparatus including an airbag and an inflator is provided. The airbag is formed by stacking a connected pair of base fabric sheets or a pair of independent fabric sheets, and joining peripheral portions of the base fabric sheets. The airbag is stored in a storage portion located in the vicinity of an outer side of an occupant seated on a vehicle seat. The inflator supplies inflation gas to the airbag in response to an impact applied to the vehicle from the exterior. The airbag is inflated and deployed between a body side portion of the vehicle and the vehicle seat. The side airbag apparatus further includes at least one pair of tucked portions located rearward of a center portion of the airbag and a joining portion. The tucked portions are formed by folding a part of the airbag. The joining portion joins the tucked portions to each other in a vertically stacked state. The width of the airbag along the widthwise direction of the vehicle in the vicinity of the tucked portions when the airbag is inflated is larger than the width of a rear portion of an airbag having no tucked portion along the widthwise direction of the vehicle when the airbag is inflated.
A preferred embodiment of the present invention will now be described with reference to
In the following, the direction in which a vehicle advances forward will be referred to as a forward direction, and the up-down direction of the vehicle is referred to as an up-down direction. A widthwise direction of the vehicle, or a lateral direction, is defined with reference to the forward direction and the up-down direction of the vehicle. In an airbag, a front-rear direction and an up-down direction are defined with reference to an inflated and deployed state.
As shown in
The vehicle seat 12 includes a seat cushion (seat portion) 13 and a seat back (backrest portion) 14. The seat back 14 is arranged at the rear portion of the seat cushion 13. The seat back 14 has a mechanism (not shown) for adjusting the inclination with respect to the seat cushion 13. A storage portion 15 is provided in an outer side portion of the seat back 14. An airbag module AM, which is a main part of the side airbag apparatus, is stored in the storage portion 15 of the seat back 14. The storage portion 15 is located in the vicinity of an outer side of an occupant P seated on the vehicle seat 12. The airbag module AM includes an airbag 20 and an inflator assembly 40 as shown in
The components shown above will now be described. In the present embodiment, the up-down direction and the front-rear direction of the airbag module AM and its components are defined with reference to the seat back 14 of the vehicle seat 12. The up-down direction refers to the direction in which the seat back 14 extends upward, and the front-rear direction is perpendicular to the up-down direction. The seat back 14 is normally used in an inclined state. The term “up-down direction” here is therefore not vertical, but is slightly inclined. Likewise, the front-rear direction is not strictly a horizontal direction, but is slightly inclined.
The airbag 20 is formed by overlapping two base fabric sheets 21, 22, which are elongated in the vertical direction, and joining the peripheral portions. The base fabric sheets 21, 22 are connected to each other at a rear side 23, which extends substantially in the up-down direction. The airbag 20, which has such a shape, is referred to as a flat bag.
The base fabric sheets 21, 22 are formed of material having high strength and flexibility so as to be easily folded. Concrete examples of the material for the base fabric sheets 21, 22 include, for example, polyester thread, polyamide thread, and the like. The shape and the size of the base fabric sheets 21, 22 are determined such that, when the airbag 20 is inflated and deployed between the vehicle seat 12 and the body side portion 11, the airbag 20 covers the lumbar region Pp and a shoulder Ps of the occupant P seated on the vehicle seat 12. The airbag 20 may be formed by overlapping two independent base fabric sheets 21, 22, and joining the peripheral portions of the sheets 21, 22.
In the joining portion of the base fabric sheets 21, 22 (hereinafter, referred to as a peripheral joining portion 24), the peripheries of the base fabric sheets 21, 22 are sewn to each other with sewing threads.
As shown in
As shown in
As shown in
As described above, in the rear portion 20R of the airbag 20, the base fabric sheets 21, 22 are valley folded along the valley fold lines 28 and mountain folded along the upper mountain fold lines 31 and the lower mountain fold lines 33. Accordingly, the upper and lower mountain fold lines 31, 33 appear adjacent to each other on the surface of the rear portion 20R of the airbag 20. The valley fold lines 28 are concealed at positions in the airbag 20 that are substantially forward of the upper and lower mountain fold lines 31, 33. The valley fold lines 28 extend linearly along the lateral direction in the rear portion 20R of the airbag 20.
As shown in
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As shown in
The retainer 42 functions as a diffuser. The retainer 42 secures the inflator 41 to a seat frame 16 in the seat back 14 together with the airbag 20 (refer to lines with dashes that alternate between one long and two short dashes in
As indicated by line with dashes that alternate between one long and two short dashes in
As shown in
In the side airbag apparatus according to the present embodiment, the impact sensor 51 detects that an impact of a magnitude greater than or equal to a predetermined value has been applied to the body side portion 11 of the vehicle. Then, based on a detection signal from the impact sensor 51, the controller 52 sends a command signal to the inflator 41 to activate the inflator 41. In response to the command signal, the gas generating agent in the inflator 41 generates inflation gas G. The inflation gas G is then jetted out through the gas ports 43. As shown in
The inflation gas G inflates each section of the airbag 20 in the storage state. The airbag 20 is then deployed while being unfolded. As indicated by lines with dashes that alternate between one long and two short dashes in
The lines with dashes that alternate between one long and two short dashes in
In the present embodiment, the tucked portions 25, 26 are located rearward of the center portion C1 of the airbag 20 in the front-rear direction. This increases the rigidity of a portion in the vicinity of the tucked portions 25, 26. In addition, the width W1 of a portion of the airbag 20 in the vicinity of the tucked portions 25, 26 is determined to meet the above described condition (W1>W2). Thus, in the vicinity of the tucked portions 25, 26, the airbag 20 is inflated to be thicker in the lateral direction than a rear portion 60R of the airbag 60. On the other hand, a front portion 20F, a lower portion 20L, and an upper portion 20U of the airbag 20, which are distant from the tucked portions 25, 26, are inflated into a tapered shape under the influence of the wide inflation in the vicinity of the tucked portions 25, 26 in the lateral direction. Therefore, as shown in
In the present embodiment, the airbag 20 has a portion that is inflated and deployed on the outer side of the lumbar region Pp of the occupant P. Particularly, since the lower portion 20L of the airbag 20, which is distant from the tucked portions 25, 26, is inflated into a tapered shape, the airbag 20 is allowed to enter the narrow gap G between the lumbar region Pp of the occupant P and the body side portion 11. The tucked portions 25, 26, which have been widely inflated in the lateral direction, are located on the outer side of the lumbar region Pp. This allows the airbag 20 to reliably restrain the lumbar region Pp of the occupant P.
The present embodiment described above has the following advantages.
(1) In the present embodiment, the rear portion 20R of the airbag 20 is folded to form the tucked portions 25, 26, which are stacked vertically and joined to each other. Further, the width W1 of the tucked portions 25, 26 when the airbag 20 is inflated is greater than the width W2 of the airbag 60 having no tucked portions 25, 26 when inflated (W1>W2).
Thus, a portion including the tucked portions 25, 26, which are located rearward of the center portion C1 of the airbag 20, can be widely inflated in the lateral direction. This ensures the restraining performance of the airbag 20. Also, the front portion 20F, the lower portion 20L, and the upper portion 20U of the airbag 20, which are distant from the tucked portions 25, 26, can be inflated into a tapered shape. This allows the front portion 20F, the lower portion 20L, and the upper portion 20U of the airbag 20 are allowed to easily enter the narrow gap G1 between the occupant P and the body side portion 11. This improves the deployment performance of the airbag 20.
(2) The airbag 20 has the tucked portions 25, 26 at a portion that is inflated and deployed on the outer side of the lumbar region Pp of the occupant P. Since the lower portion 20L of the airbag 20 is inflated into a tapered shape, the airbag 20 is reliably allowed to enter the narrow gap G1 between the body side portion 11 and the lumbar region Pp. This improves the deployment performance of the airbag 20. Also, since the lumbar region Pp is restrained by the tucked portions 25, 26, which have been widely inflated in the lateral direction, the restraining performance of the airbag 20 is improved. That is, the airbag 20 reliably protects the lumbar region Pp of the occupant P from an impact due to side collision.
(3) In the case of a prior art side airbag apparatus, in which an airbag has a three-dimensional shape with an increased number of base fabric sheets, the additional base fabric sheets each need to be sewn to other base fabric sheets at the periphery. In this case, the airbag is harder in the sewn portions than in non-sewn portions, and the sewn portions enlarge the area of increased thickness of the airbag. This makes the process for folding the airbag into a storage state troublesome.
In this regard, parts (the portions 34, 35) of the airbag 20 (the base fabric sheets 21, 22) of the present embodiment are formed into the tucked portions 25, 26. In this case, the tucked portions 25, 26 can be joined to each other simply by sewing along the upper and lower mountain fold lines 31, 33. Thus, the airbag 20 is hardened by a small degree due to sewing. Also, in a state where the airbag 20 is folded, the area in which the thickness of the airbag 20 is increased by sewn portions is reduced. Thus, compared to airbags having a three-dimensional shape, the airbag 20 is easily folded. Even if the tucked portions 25, 26 are joined by adhesion instead of sewing, the above described advantages are achieved.
(4) The side airbag apparatus according to the present embodiment is superior to a case where the tucked portions 25, 26 are located in the front portion 20F of the airbag 20 in terms of the following items. That is, the rigidity of a portion in which the tucked portions 25, 26 are vertically stacked and sewn to each other is higher than that in other portions. If such a sewn portion exists in the front portion 20F of the airbag 20, the sewn portion passes through the gap G1 between the occupant P and the body side portion 11, while contacting the occupant P. In this respect, the tucked portions 25, 26 are located only in the rear portion 20R of the airbag 20 in the present embodiment. This reduces the likelihood of contact between a sewn portion and the occupant P.
(5) A part of the rear portion 20R of the airbag 20 is folded inward so that the tucked portions 25, 26 are formed. Further, the tucked portions 25, 26 are sewn to each other along the upper and lower mountain fold lines 31, 33 while being vertically stacked. The tucked portions 25, 26 are therefore located in the airbag 20. Therefore, a bulge formed by the tucked portions 25, 26 is not exposed to the outside of the airbag 20. This eliminates drawbacks caused by contact between the tucked portions 25, 26 and other members.
(6) The inner joining portion 36 is formed by sewing along the upper and lower mountain fold lines 31, 33. The inner joining portion 36 joins the tucked portions 25, 26 to each other in a vertically stacked state. That is, the tucked portions 25, 26 can be joined to each other simply by sewing sections along the upper and lower mountain fold lines 31, 33. Thus, compared to a case where adjacent tucked portions 25, 26 are joined to each other by adhesion, the tucked portions 25, 26 are easily joined to each other.
(7) The shape of the tucked portions 25, 26 can be changed by changing the length of the valley fold lines 28 and the inclination of the upper and lower mountain fold lines 31, 33 of the base fabric sheets 21, 22. The thickness of the tucked portions 25, 26 in the inflated state of the airbag 20 can be changed through such a simple procedure.
The present invention may be embodied in the following forms.
The tucked portions 25, 26 may be located at any position that is rearward of the center portion C1 of the airbag 20. For example, the tucked portions 25, 26 may be located above the center portion C2 of the airbag 20.
A plurality of tucked portions 25, 26 may be provided in the rear portion 20R of the airbag 20.
The tucked portions 25, 26 may be folded rearward and to the exterior of the airbag 20. In this case, the tucked portions 25, 26 bulge to the exterior of the airbag 20. However, the same operations and advantages as the above illustrated embodiment are achieved.
The rear portion 20R of the airbag 20 may be folded two or more times to form two or more pairs of tucked portions, and the pairs of the tucked portions may be vertically stacked and joined to each other.
Instead of sewing the tucked portions 25, 26 to each other along the upper and lower mountain fold lines 31, 33, the tucked portions 25, 26 may be adhered to each other using adhesive.
In the above illustrated embodiment, the tucked portions 25, 26 are joined to each other along the upper and lower mountain fold lines 31, 33. However, the tucked portions 25, 26 may be joined to each other at other sections. In this case, means for joining includes sewing and adhesion. For example, the tucked portions 25, 26 may be adhered to each other in the entire portions 34, 35.
Instead of the lateral width of the tucked portions 25, 26 when the airbag 20 is inflated, the lateral width in the vicinity of the tucked portions 25, 26 may be set as the width W1. In this case also, the width W1 is set to be greater than the lateral width W2 of the rear portion 60R of the airbag 60 having no tucked portion when the airbag 60 is inflated.
The storage portion 15 may be provided in the body side portion 11. In this case, the storage portion 15 is located in the vicinity of an outer side of an occupant P seated on the vehicle seat 12.
The present invention may be applied to a side airbag apparatus equipped with an airbag 20 having no portion for protecting the lumbar region Pp of the occupant P. In this case also, the deployment performance of the airbag 20 is improved while maintaining the restraining performance.
Number | Date | Country | Kind |
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2008-032296 | Feb 2008 | JP | national |