1. Field of the Invention
The present invention relates to an air bag, especially to a head protecting air bag mounted on an automobile. More particularly, the invention relates to a structure of a belt-like coupling part extending from a longitudinal end portion of the air bag and joined to a vehicle.
2. Related Art
The related art head protecting air bags of this kind include a structure which uses a member formed separately from a head protecting air bag and utilized as a member of a coupling part for joining the end portion in the longitudinal direction of the vehicle of the air bag to a portion of the vehicle, and which is fixed to the air bag, this structure being disclosed in a patent publication (refer to, for example, JP-A-2004-182026). A head protecting air bag of a structure having a member formed separately from the air bag and similar to a belt is also disclosed in a patent publication (refer to, for example, JP-A-2001-071856). A head protecting air bag of a structure in which a non-inflatable part of the air bag is extended as a member of a coupling part is also disclosed in a patent publication (refer to, for example, JP-A-2001-270413).
However, in order to form the coupling part utilizing a member made separable from the air bag, it is necessary that the connecting member be secured firmly to the air bag, so that the connecting member attachment (fixing) step has to be carried out in the air bag manufacturing stage.
In order to employ a method of forming the member of the coupling part by extending a non-inflatable part of the air bag, the non-inflatable part is necessarily extended by a distance (length) corresponding to a distance between the end portion of an inflatable part of the air bag and the attachment portion of the vehicle. Therefore, a ground cloth (a woven material) is used excessively in a corresponding quantity.
Therefore, the structure for the coupling part has room for improvement, i.e. a higher yield thereof, and an inexpensive method of manufacturing the same have to be attained.
The present invention aims at solving these problems, and providing an air bag, suitable for a head protection head, having a simple structure and capable of being manufactured inexpensively.
One aspect of the air bag according to the present invention has an air bag comprising: an inflatable part; a non-inflatable part; and a coupling part defined in an end portion of the air bag for coupling to a vehicle; wherein a slit portion is formed in the air bag such that that the coupling part is separatable from the non-inflatable part while being connected at a connecting end portion of the coupling part.
In this invention, it is preferable that, in the slit portion, the connecting end portion of the coupling part be provided with a curved section.
In this invention, it is preferable that the curved section be arcuate and has a predetermined radius.
Furthermore, it is preferable in these inventions that the coupling part be formed to a substantially a belt-like shape, and that the narrow portion of the coupling part in which a width thereof becomes the smallest be provided in the section thereof which is other than the connecting end portion thereof.
In these inventions, it is preferable that a terminal part of the connecting end portion of the coupling part be provided with a substantially circular hole-like section.
In the air bag according to the present invention, a slit portion is provided in a part of the non-inflatable part so that a section of the coupling part except the connecting end portion thereof becomes able to be separated from the non-inflatable part with the connecting end portion of the coupling part and the non-inflatable part in a joined state, the non-inflatable part thus forming the coupling part. Therefore, the non-inflatable part of the air bag and coupling part are put in a continuous united state in advance, so that the step of attaching the air bag to the coupling part is omitted. Since the coupling part is used separately from the non-inflatable part, the non-inflatable part may not be extended to even a distance (length) corresponding to that between the end section of the inflatable part of the air bag and the attachment portion of the vehicle, and the quantity of use of the ground cloth (woven material) serving as a material for the coupling part for the air bag can be minimized. This enables the air bag to be formed to a simple structure and manufactured inexpensively.
When a curved section is provided on the slit portion of the connecting end portion of the coupling part, the concentration (i.e. stress concentration) of a load imparted to the terminal end portion of the slit portion is scattered on the curved section of the coupling part. Therefore, the breakage starting from this portion of the coupling part can be inhibited. Since forming a part of the slit portion only to a curved shape can meet the purpose, the coupling part, which is capable of inhibiting the breakage of the air bag when the air bag is expanded, of the air bag can be formed to a simple structure and manufactured inexpensively.
When the curved section is formed to a predetermined radius, the above-mentioned concentration of a load is substantially uniformly scattered on the curved section. Accordingly, the breakage starting from this portion of the air bag can be inhibited more stably. Since the curved section may only be formed to an arcuate shape having a predetermined radius, the coupling part, which is capable of inhibiting the breakage thereof when the air bag is expanded, can be formed to a simple structure and manufactured inexpensively.
When the coupling part is formed to a belt-like shape, and, when the portion thereof which becomes smallest in width is provided on the portion of the same which is other than the connecting end portion of the coupling part, this thinnest portion becomes a portion on which a load is readily concentrated when the air bag is expanded. Therefore, this thinnest portion is set to a dimension (width) which permits the narrow portion to sufficiently withstand a load occurring due to the expansion of the air bag, the coupling part as a whole necessarily becomes able to sufficiently withstand the load occurring due to the expansion of the air bag. The connecting end portion in which the coupling part and non-inflatable part continue naturally has a size larger than that of this narrow portion. Therefore, the strength of the coupling part during the expansion of the air bag is necessarily secured. Since the narrow portion having a sufficient strength may only be provided on a general portion of the belt-like coupling part, the coupling part in which the strength necessary when the expansion of the air bag takes place is secured can be manufactured to a simple structure.
When a substantially circular hole-like section is provided in the terminal part of the connecting end portion of the coupling part in the slit portion, the concentration (i.e. stress concentration) of a load imparted to the terminal end portion of the slit portion when the air bag is expanded is scattered substantially uniformly on a region around the hole-like section. Therefore, the breakage of the air bag starting from this section can be inhibited. Since the providing of a substantially circular hole-like section only in the terminal end portion of the slit portion, the coupling part of the air bag which can inhibit the breakage of the air bag occurring during the expansion thereof can be formed to a simple structure, and manufactured inexpensively.
The embodiments of the present invention will now be described on the basis of the drawings.
A head protecting air bag 10 (which will hereinafter be referred to the air bag 10) in an embodiment is used for a head protecting air bag apparatus mounted on a vehicle as shown in
As shown in
The air bag 10 of the embodiment has attachment portions 14 (in
As shown in
In this embodiment, the coupling part 20 is formed as a substantially belt-like member extending in the substantially vertical direction by utilizing the non-inflatable part 11 in a front end section with respect to the vehicle of the air bag 10. The embodiment is not limited to this, i.e., the coupling part 20 may also be formed as a substantially belt-like member extending in the substantially longitudinal direction by utilizing the non-inflatable part 11 in a lower end section with respect to the vehicle of the air bag 10. In addition, the coupling part 20 may also be formed as a substantially belt-like member by utilizing a combination of these non-inflatable parts 11. Namely, the coupling part 20 may also be formed as an L-shaped substantially belt-like member, a diagonally arranged substantially belt-like member, and a substantially belt-like member in which adjacent U-shaped members are arranged continuously in an alternately changed manner at the upper and lower portions thereof so as to gain the length (like a sine wave). As a further applied example, the coupling part may be formed as a structure in which the coupling part is joined to a part above (for example, a position of an attachment portion 14a) the rear pillar RP by utilizing the non-inflatable part 11 at the rear end section of the vehicle.
The separating end portion 23 of the coupling part 20 is provided with the attachment portion 24 therefor used to secure the coupling part 20 to the front pillar FP of the vehicle. The attachment portion 24 of the coupling part 20 is provided with attachment holes 25 therein, through which bolts or clips etc. for securing the coupling part 20 to the vehicle are inserted, in the same manner as the attachment portion 14 for securing the air bag 10 to the roof side rail RR. In the embodiment, the air bag 10 is fixed to the front pillar FP of the vehicle by using bolts (not shown) via the attachment portion 24. In the attachment portion 24 of the coupling part 20 in this embodiment, a base portion 24a and a flap portion 24b are arranged side by side in the longitudinal direction when the air bag 10 is cut out from a base cloth. After the air bag 10 is cut out from the base cloth, the air bag 10 is folded along a fold line S, and the flap portion 24b is thereby folded toward the base portion 24a, the base portion 24a and flap portion 24b being laminated on each other. The direction in which the folding portion 24b is bent may be either the direction extending this side of the outer surface of
The general portion 22 of the coupling part 20 is formed as a substantially a belt-like member extending substantially in the vertical direction with respect to the air bag 10 along fine lines (warp VS). This general portion 22 is provided with convex sections 26 as discrimination signs for improving the operation efficiency (preventing the occurrence of erroneous assembling) during the mounting of the head protecting air bag apparatus on a vehicle. The general portion 22 has a constant dimension (width) H0 except these convex sections 26. In this embodiment, the portions having this dimension H0 form narrowest sections 22a of the general portion 22. The coupling part 20 also functions as a so-called tension belt as well so that the air bag 10 is expanded and developed with a suitable tension. Therefore, it is necessary that the coupling part 20 be resistant a certain degree of tension. During this time, the general portion 22, which forms the belt-like portion, resists owing to this tension as in this embodiment even a load concentrated thereon. When the narrow portion 22a of the dimension H0 is provided, the coupling part 20 necessarily has a strength high enough to resist sufficiently even when the air bag 10 is developed and expanded. Moreover, the tension is imparted to the general portion 22, which is a part of the belt-like portion, in the longitudinal direction thereof, so that, when the narrow portion 22a has a certain degree of the dimension H2 in the longitudinal direction of the general portion 22 as in the embodiment, the portion of the dimension H2 necessarily receives the concentrated load in a substantially uniformly. Therefore, the coupling part becomes a structure in which a load is difficult to be concentrated on one point, so that the structure is desirable. In the embodiment, the dimension H2 of the shortest portion is 30 mm, and that H0 of the portions (the narrow portions 22a) 175 mm in total. There may be a plurality of narrow portions 22a as in this embodiment, or may be restricted to one position as long as the narrow portion 22 has a satisfactory strength even when consideration is not given to the concentration of a load to one point. However, when the dimension H0 is varied in the portion adjacent to the narrow portion 22a, it is preferable that the dimension H0 be changed gently and gradually so that the concentration of a load in the point of change is inhibited.
The coupling part 20 is obtained by providing a slit portion 27 in the non-inflatable part 11 of the air bag 10, and the connecting end portion 21 of the coupling part 20 is joined in one body continuously to the non-inflatable part 11 on the front side of the vehicle of the air bag 20. The slit portion 27 starts being bent from the end section of the connecting end portion 21 of the general portion 22 toward an anti-outer shape side (inflatable part 12) of the air bag 10, and a curved section 28 is formed on the connecting end portion 21 (more in detail, the section immediately before the terminal end region of the slit portion 27 on the side of the connecting end portion 21 of the coupling part 20 of the slit portion 27). In the embodiment, this curved section 28 is formed as an arc obtained by dividing a circle of a radius of 25 mm into substantially four parts. It is preferable that the radius R of this curved section 28 and the dimension H0 of the narrow portion 22a be set to the dimension H0≦the radius R taking into consideration the scattering of the concentrated load imparted to this curved section 28 during the expansion and development of the air bag 10. In this case, the dimension H1 of the connecting end portion 21 of the coupling part 20 and the dimension H0 of the narrow portion 22a may be determined as long as the relational expression of the dimension H0≦the dimension H1 is effected. In this embodiment, the slit portion 27 is formed as a slit which is formed by simply cutting the non-inflatable part, and which has no width (width: 0 mm). The slit portion 27 may also be formed as a notch having a width like a gap. When the slit portion 27 is formed as a notch, the distance between the outer peripheral part formed by the notch and constituting the outer peripheral shape of the air bag 10 and the inflatable part 12 is set in proportion to the distance L1.
As shown in
In the embodiment, the outer shape of the connecting end portion 21 is as shown by a solid line in
In the condition in which the air bag 10 is mounted on a vehicle and developed and expanded as shown in
The air bag 10 may be made of two laminated cloths as other modified example. The two cloths in this example may be combined with each other by bonding or sewing using bonding means not specifically limited. In this case, the coupling part 20 may be provided with a non-inflatable part 11 in which two cloths are laminated on each other, a one-piece cloth structure of either one of such cloths. The air bag 10 may be made of either non-coated cloths or coated cloths. Furthermore, the cut surfaces (end portions) of the outer surface, slit portion 27 and hole-like section 30 may be subjected to a fraying preventing treatment (for example, heating these portions and melting and solidifying the cut surfaces of the base cloths (fiber) of the air bag and the like).
Number | Date | Country | Kind |
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2005-248818 | Aug 2005 | JP | national |