Air bag system

[0002] 1. Field of the Invention

[0003] The present invention relates to an air bag system having an air bag in which an inflator for generating gas is mounted inside through an insertion opening provided to a mounting base portion of the air bag and mainly to an improvement of an air bag structure for preventing leakage of gas generated by the inflator through the insertion opening for the inflator.

[0004] 2. Description of the Related Art

[0005] As an air bag system for protecting a passenger, there is proposed a system in which an inflator for generating gas is mounted to an inside through an insertion opening provided to a mounting base portion of an air bag and a closing cloth with which the insertion opening for the inflator is covered is provided to an outside of the air bag so as to prevent leakage of gas through the insertion opening for the inflator to the outside of the air bag (Japanese Patent Application Laid-open No. 11-115673).

[0006] In the air bag system, a side of the closing cloth is sewn on the outside face of the air bag and the closing cloth is pulled to the mounting base portion of the air bag so as to cover the insertion opening for the inflator with the closing cloth. In this air bag system, if the gas generated from the inflator acts on the closing cloth through the insertion opening of the mounting base portion, the closing cloth bulges away from the outside face of the air bag. Therefore, there is a fear of leakage of the gas from unsewed edge sides of the closing cloth.

[0007] In the air bag system, a reinforcing cloth having an opening corresponding to the insertion opening for the inflator is provided to an inside of the air bag in addition to the closing cloth. However, it is impossible to prevent the gas generated from the inflator from acting toward the closing cloth through the insertion opening of the mounting base portion even though the reinforcing cloth is provided.

[0008] It is a main object of the present invention to provide an air bag system for reliably preventing leakage of gas generated from an inflator through an insertion opening provided to a mounting base portion of an air bag.

[0009] In an air bag system according to a first aspect of the invention, the air bag system has an air bag in which an inflator for generating gas is mounted through an insertion opening formed at a mounting base portion of the air bag and the air bag system has an applied cloth mounted to an outside of the air bag such that the insertion opening for the inflator is covered with the applied cloth by making one side of the applied cloth an open hole and fixing edges of three other sides of the applied cloth to an outside face of the mounting base portion.

[0010] In an air bag system according to a second aspect, the open hole is capable of being opened into an openmouthed shape.

[0011] In an air bag system according to a third aspect, the applied cloth is mounted to the outside of the air bag such that the open hole on the one side is positioned on a side held by the inflator mounted in the air bag.

[0012] FIG. 1 is an explanatory view showing an air bag in an inflated and deployed state in a partially cutaway side view of an automobile seat having an air bag system according to the present invention.

[0013] FIG. 2 is a perspective view showing a seat back of the automobile seat having the air bag system according to the invention.

[0014] FIG. 3 is a partial sectional view of the seat back of the automobile seat having the air bag system according to the invention.

[0015] FIG. 4 is one-side view of a deployed air bag mounted to the air bag system according to the invention.

[0016] FIG. 5 is the-other-side view of the deployed air bag mounted to the air bag system according to the invention.

[0017] FIG. 6 is a sectional view partially showing an insertion opening and an applied cloth of the air bag mounted to the air bag system according to the invention.

[0018] FIG. 7 is an explanatory view showing the air bag system according to the invention in terms of an inflator mounting step.

[0019] FIG. 8 is an exploded perspective view of the inflator and a retainer mounted to the air bag system according to the invention.

[0020] An embodiment of the invention will be described below by reference to the accompanying drawing. The illustrated embodiment forms an air bag system E mounted to a left side of a seat back B of a front passenger seat as shown in FIG. 1.

[0021] As shown in FIGS. 2 and 3, the air bag system E is mounted in the seat back B by folding an air bag 1 such that the air bag 1 can be inflated and deployed, housing the air bag 1 in an air bag case C that can be opened by inflation pressure of the air bag 1, and bolting the air bag case C to a side plate P of a seat back frame F by using the air bag case C as a base. A seam L between a front cover portion a with which a bank portion of the seat back B is covered and a side cover portion b becomes a rupture portion at which rupture takes place as a result of inflation and deployment of the air bag 1.

[0022] As shown in FIG. 4, the air bag 1 is formed by sewing a bag main body 1afolded such that the bag main body 1acan be inflated and deployed and a mounting base portion 1bhaving a narrower width than the bag main body 1ainto a bag shape. In the air bag 1 an insertion opening 1cused for mounting an inflator that will be described later to an inside is provided to the mounting base portion 1b. The insertion opening 1cis formed of a slit or the like that extends from a substantially center portion of the mounting base portion 1btoward faces of the bag main body 1aon opposite sides of the mount base portion 1.

[0023] As shown in FIGS. 4 and 5, an applied cloth 2 with which the insertion opening 1cfor the inflator is covered is fixed to an outside of the air bag 1 for preventing leakage of the gas such that one side of the cloth 2 provides an open hole 2aand the edges of three other sides 2b, 2c, and 2dare sewn on an outside face of the mounting base portion 1b.

[0024] The applied cloth 2 is formed by cutting cloth material which is similar to material of the air bag 1 and which does not leak gas. The applied cloth is a band-shaped member that is longer than at least the insertion opening 1cextending from the substantially center portion of the mounting base portion 1btoward the faces of the bag main body 1aon the opposite sides of the mounting base portion 1b.

[0025] As shown in FIG. 6, the one side of the applied cloth 2 is preferably formed to provide the open hole 2aso that it can be opened into an openmouthed shape and the applied cloth 2 is preferably mounted to the outside of the air bag 1 such that the insertion opening 1cfor the inflator is covered with the applied cloth 2. The applied cloth 2 is preferably mounted to the outside of the air bag 1 by positioning the open hole 2aon the one side of the applied cloth 2 on a side held by the inflator which is mounted in the air bag 1 and which will be described later.

[0026] In the air bag 1, the inflator 3 as shown in FIGS. 7 and 8 is mounted such that the inflator 3 is positioned at the mounting base portion 1b. The inflator 3 generates gas necessary to inflate and deploy the air bag 1 from an inflator main body 3aand has associated equipment such as a shock sensor and a harness 3band connectors 3cand 3dnecessary to form a circuit.

[0027] The inflator 3 is retained by the retainer 4 and mounted in the air bag 1 together with the retainer 4. The retainer 4 is formed of a holder potion 4ain which the inflator main body 3ais fitted and retained, a base plate portion 4bas a placing plate, and tightening bolts 4cand 4daffixed on the base plate portion 4b.

[0028] Because the tightening bolts 4cand 4dof the retainer 4 are affixed on the base plate portion 4b, the bolts 4cand 4dbecome fixed shafts of the inflator 3 together with the retainer 4. Through holes 2eand 2f(only those on the applied cloth are shown) which correspond to the tightening bolts 4cand 4dand through which the tightening bolts 4cand 4dare inserted are formed in a bottom face of the air bag case C, the mounting base portion 1bof the air bag 1, and the applied cloth 2.

[0029] In order to assemble the respective portions into the air bag system E, the inflator main body 3ais retained by the holder portion 4aof the retainer 4 and the inflator 3 excluding the harness 3band connectors 3cand 3dis put in the air bag 1 through the insertion opening 1cprovided to the mounting base portion 1bafter opening the open hole 2aof the applied cloth 2. At this time, because the open hole 2aof the applied cloth 2 can be opened into an openmouthed shape, the inflator 3 can be easily put in the air bag 1 though the insertion opening 1ctogether with the retainer 4.

[0030] The tightening bolts 4cand 4dof the retainer 4 are inserted into the through holes 2eand 2fformed on the mounting base portion 1bof the air bag 1 and a side face of the applied cloth 2 such that the bolts 4cand 4dproject outward. By connecting the harness 3bincluding the connector 3dto the inflator main body 3athrough the connector 3dafterward from the outside of the air bag 1 through a through hole 1d(see FIG. 7) formed on a side portion of the air bag 1, the harness 3bis drawn to the outside.

[0031] The air bag system formed as described above is housed in the air bag case C by folding the air bag main body 1asuch that the air bag main body 1acan be inflated and deployed and with the tightening bolts 4cand 4dof the retainer 4 projecting to the outside through the through holes formed on the bottom face. The air bag system is mounted in the seat back B by using the air bag case C as the base and bolting the air bag system to the side plate P of the seat back frame F through the tightening bolts 4cand 4dof the retainer 4.

[0032] In the air bag system, because the applied cloth 2 is mounted such that the insertion opening 1cfor the inflator is covered with the applied cloth 2 by sewing the three sides 2b, 2c, and 2dexcluding the open hole 2aon the one side of the applied cloth 2 on the outside face of the mounting base portion 1b, the insertion opening 1cfor the inflator 3 can be closed more tightly with the applied cloth 2 and leakage of the gas from the insertion opening 1ccan be prevented reliably even if the gas is generated by the inflator 3 and the gas pressure is received from the insertion opening 1c.

[0033] Furthermore, because the open hole 2aon the one side of the applied cloth is positioned on the side where the inflator 3 holds the mounting base portion 1bof the air bag 1, the open hole 2aas well as the mounting base portion 1bof the air bag 1 formed with the insertion opening 1ccan be held by the holder portion 4aand the base plate portion 4bof the retained 4. Therefore, the insertion opening 1cfor the inflator can be sealed more reliably and the mounting base portion 1bof the air bag 1 can be reinforced.

[0034] As described above, according to the air bag system of the first aspect of the invention, by mounting the applied cloth to the outside of the air bag such that the insertion opening for the inflator is covered with the applied cloth by making the one side of the applied cloth form the open hole and fixing the edges of the three other sides of the applied cloth to the outside face of the mounting base portion, it is possible to close the insertion opening for the inflator more tightly with the applied cloth when the gas is generated by the inflator, to reliably prevent leakage of the gas from the insertion opening for the inflator, and to reinforce the mounting base portion of the air bag with the applied cloth.

[0035] According to the air bag system of the second aspect of the invention, by mounting the applied cloth which has the open hole capable of being opened into the openmouthed shape and with which the insertion opening for the inflator is covered to the outside of the air bag, the inflator can be easily put in the air bag through the insertion opening.

[0036] According to the air bag system of the third aspect of the invention, by mounting the applied cloth to the outside of the air bag such that the open hole on the one side is positioned on the side held by the inflator mounted in the air bag, the insertion opening for the inflator can be sealed more reliably.