Airbag system

[0001] The present invention relates to an airbag system for protecting an occupant of a vehicle such as an automobile in the event of a crash. More particularly, the present invention relates to an airbag system including an airbag having an interior partitioned into a plurality of chambers.

[0002] A conventional airbag system is constructed to inflate an airbag toward an occupant by a gas generator so that the inflated airbag receives a body of the occupant. Japanese Patent Publication (Kokai) No. 2000-177527 has disclosed a structure in which a lower part of an airbag is inflated at a higher inner pressure than that of an upper part for receiving a lumbar part of the occupant. FIG. 5 is a side view of a seat equipped with the airbag system. FIG. 6 is an enlarged sectional view of a section 6 of the side airbag system shown in FIG. 5.

[0003] An airbag 18 is partitioned into an upper chamber 20 and a lower chamber 22 with a seam 24. A rear end of the seam 24 is positioned slightly away from a rear rim of the airbag 18. A cylindrical gas distributor 30 is placed in a space between the rear end of the seam 24 and the rear rim of the airbag 18. A rod-like gas generator 36 is placed in the gas distributor 30. Upper and lower ends of the gas distributor 30 are formed with pipe clips 32 and 34 for fixing the gas generator 36. The pipe clips 32 and 34 seal a portion between the gas generator 36 and the gas distributor 30. The pipe clips 32 and 34 are attached to mounting sections 26 of a seat back 14.

[0004] The gas distributor 30 has upper-chamber discharge ports 42 for discharging gas from the gas generator 36 into the upper chamber 20, and lower-chamber discharge ports 44 for discharging the gas into the lower chamber 22. The lower-chamber discharge ports 44 are larger than the upper-chamber discharge ports 42. Therefore, when the gas generator 36 is activated, the airbag 18 is inflated so that the upper chamber 20 has an inner pressure about 0.5 bar and the lower chamber 22 has an inner pressure about 1.5 bars.

[0005] The side airbag system disclosed in Japanese Patent Publication (Kokai) No. 2000-177527 includes the gas distributor 30, thereby increasing a cost. In the side airbag system, the discharge ports 42 and 44 are directed forward of the seat. Accordingly, the gas from the gas generator 36 first inflates the airbag 18 forward of the seat and then inflates the airbag 18 vertically, so that the airbag 18 is inflated vertically later.

[0006] In view of the problems described above, an object of the present invention is to provide an airbag system with a simple structure at a low cost.

[0007] It is another object of the present invention to provide an airbag system in which the airbag is quickly inflated vertically.

[0008] Further objects and advantages of the invention will be apparent from the following description of the invention.

[0009] According to the present invention, an airbag system includes an airbag having an occupant side surface facing an occupant and an opposite side surface facing a vehicle body in an inflated state, and having an interior partitioned into a plurality of chambers including at least an upper chamber and a lower chamber; a gas generator disposed in the airbag; and a gas distributor having a discharge port for discharging gas from the gas generator into at least the upper chamber and the lower chamber. The gas distributor has a gas-distributing connecting line extending linearly for connecting the occupant side surface and the opposite side surface of the airbag.

[0010] In the present invention, the airbag system has the gas distributor constructed by connecting the occupant side surface and the opposite side surface of the airbag. Accordingly, it is not necessary to provide a separate gas distributor, thereby making the airbag system simple and easy to produce. The airbag system of the invention protects the occupant in case of a side collision as well as roll over.

[0011] According to the invention, the gas-distributing connecting line extends vertically, and a gas generator housing chamber is formed between the gas-distributing connecting line and a side rim of the airbag. The housing chamber has a gas discharge port communicating with the lower chamber downwardly at a lower end thereof. The lower-chamber discharge port is larger than an upper-chamber discharge port.

[0012] In the present invention, the side airbag system has the lower-chamber discharge port directed downwardly. Therefore, when the gas generator is activated, the airbag is inflated downwardly quickly. Also, the lower-chamber discharge port is larger than the upper-chamber discharge port. Therefore, the lower chamber is inflated at a higher inner pressure than that of the upper chamber at an early stage of the inflation. In this case, the gas generator may be formed in a rod shape having a gas jet port at one end thereof, and may be disposed in the housing chamber with the gas jet port arranged downwardly. With such an arrangement, the gas generator ejects the gas easily into the lower chamber to inflate the lower chamber early.

[0013] According to the invention, the housing chamber may be arranged between the upper chamber and the side rim of the airbag. Accordingly, it is possible to increase a capacity of the lower chamber. The housing chamber may extend vertically along the side rim of the airbag, so that the gas generator inflates the housing chamber to deploy the airbag upward quickly.

[0014] According to the invention, a lower part of the gas-distributing connecting line may be positioned close to the side rim of the airbag. Accordingly, it is possible to control an amount of the gas supplied to the lower chamber and the upper chamber.

[0015] According to the invention, the airbag may be partitioned into a plurality of chambers with a partitioning connecting line extending linearly and connecting the occupant side surface and the opposite side surface. The gas-distributing connecting line and the partitioning connecting line may be overlapped. Accordingly, it is possible to make the airbag system further simple and easy to produce.

[0025] Hereunder, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view of a vehicle seat equipped with an airbag system according to an embodiment of the present invention. FIG. 2(a) is a sectional view of the airbag taken along line 2(a)-2(a) in FIG. 1, FIG. 2(b) is a sectional view of the airbag taken along line 2(b)-2(b) in FIG. 2(a), and FIG. 2(c) is a sectional view of the airbag taken along line 2(c)-2(c) in FIG. 2(a).

[0026] As shown in FIG. 1, an airbag 1 is inflated along a window side of a seat 10. The seat 10 includes a seat cushion 11, a seat back 12, and a headrest 13. A casing (not shown) of the airbag system is provided at a side of the seat back 12, in which the airbag 1 is housed in a folded state and covered with a module cover (not shown).

[0027] The airbag 1 is formed such that a sheet such as a cloth and a resin sheet (cloth in the embodiment) is formed in a bag shape. An interior of the airbag 1 is partitioned into a lower chamber 1a and an upper chamber 1b with a linear connecting portion (a seam 2 in this embodiment). The seam 2 connects an occupant side surface 1p of the airbag 1 and an opposite side surface 1q together. The seam 2 has a substantially L-shape having a substantially horizontal section 2a and a vertical section 2b.

[0028] As shown in FIG. 2(a), the vertical section 2b of the seam 2 extends vertically and is positioned slightly away from a rear end of the airbag 1. A vertically extending housing chamber 4 is formed at a portion between the vertical section 2b and the rear rim of the airbag 1. A front end of the horizontal section 2a of the seam 2 is connected to a front rim of the airbag 1.

[0029] The housing chamber 4 houses a rod-shaped gas generator 3. A longitudinal direction of the gas generator 3 is aligned in a vertical direction. The gas generator 3 includes gas jet ports 3b at a lower end thereof. Two stud bolts 3a project from the gas generator 3 backward of the airbag 1 through the rear rim of the airbag 1. The stud bolts 3a are fastened to the casing of the airbag system with nuts. With this arrangement, the gas generator 3 and the airbag 1 are fixed to the casing.

[0030] As shown in FIG. 2(a), a clearance for a gas passage is provided between an outer circumference of the gas generator 3 and the vertical section 2b of the seam 2. A gas discharge port 4a is provided at a lower end of the housing chamber 4 between a rear end of the horizontal section 2a and the rear rim of the airbag 1, and opens downwardly into the lower chamber 1a. A gas discharge port 4b is provided at the upper end of the housing chamber 4 between an upper end of the vertical section 2b and an upper rim of the airbag 1, and opens forward into the upper chamber 1b. The upper chamber 1b includes a vent hole 5.

[0031] In the airbag system with such a structure, when a vehicle receives an impact or rolls over, the gas generator 3 ejects the gas. The gas flows into the lower chamber 1a and the upper chamber 1b from the gas discharge ports 4a and 4b to inflate the lower chamber 1a and the upper chamber 1b, respectively. Thus, the airbag 1 deploys along the window side of the seat 10, as shown in FIG. 1.

[0032] In the airbag system, the housing chamber 4 extends vertically, and the lower-chamber discharge port 4a is directed downwardly. Also, the gas jet ports 3b are arranged downwardly in the vicinity of the lower-chamber discharge port 4a. Therefore, when the gas generator 3 is activated, the lower chamber 1a of the airbag 1 is first inflated quickly, then the housing chamber 4 deploys vertically quickly, and thereafter the upper chamber 1b is inflated.

[0033] The lower gas-discharge port 4a has a size larger than that of the upper gas-discharge port 4b. Accordingly, a larger amount of the gas is supplied to the lower chamber 1a at a higher pressure than that in the upper chamber 1b. Furthermore, the gas jet ports 3b of the gas generator 3 are arranged at the lower end of the gas generator 3. Accordingly, it is possible to supply a larger amount of the gas to the lower chamber 1a at a higher pressure. As a result, the lower chamber 1a is inflated early at a high inner pressure to receive a lateral movement of the lumbar part of the occupant. The upper chamber 1b is inflated at a lower inner pressure than that of the lower chamber 1a, thereby receiving an upper part of the occupant softly.

[0034] According to the invention, it is possible to make the arrangement simple in which the lower chamber 1a, the upper chamber 1b, and the housing chamber 4 are partitioned with seam 2, thereby making it easy to produce.

[0035] FIGS. 3(a) and 3(b) are sectional views of side airbag systems according to other embodiments of the invention, respectively. In an airbag 1A shown in FIG. 3(a), the gas discharge port 4a of the seam 2 (a connecting section of the horizontal section 2a and the vertical section 2b) closely contacts the rear rim of the airbag 1A. Accordingly, the gas discharge port 4a connecting to the lower chamber 1a has an opening smaller than that in FIG. 2.

[0036] With this arrangement, it is possible to control an inflation speed and an inner pressure of the lower chamber 1a by adjusting a distance between the seam 2 and the airbag 1A. It is also possible to change a size of the gas discharge port 4b to control an inflation speed and an inner pressure of the upper chamber 1b and the lower chamber 1a by adjusting a distance between the upper end of the vertical section 2b of the seam 2 and the upper rim of the airbag 1 (not shown). In the embodiment, the gas discharge port 4b may be disposed in the middle of the vertical section 2b of the seam 2, as in an airbag 1B shown in FIG. 3(b).

[0037] In the embodiments described above, the airbags 1, 1A, and 1B are partitioned into two chambers, i.e. the upper chamber 1b and the lower chamber 1a. Alternatively, the airbags 1, 1A, and 1B may be partitioned into three or more chambers.

[0038] FIGS. 4(a) and 4(b) are sectional views showing airbags 1C and 1D, respectively. Each of the airbags 1C and 1D has a substantially horizontal seam 6, and a middle chamber 1c is provided between the upper chamber 1b and the lower chamber 1a. A front end of the seam 6 is connected to front rims of the airbags 1C and 1D, respectively. In the airbag 1C, the vertical section 2b of the seam 2 has a gas discharge port 4c communicating with the middle chamber 1c between the horizontal section 2a and the seam 6. In the airbag 1D, the gas discharge port 4c is provided in the seam 6.

[0039] Other arrangements of the airbags 1C and 1D are the same as those of the airbag 1 shown in FIGS. 1, 2(a) and 2(b). Accordingly, the same reference numerals in FIGS. 4(a) and 4(b) indicate the same components as those in FIGS. 1, 2(a) and 2(b).

[0040] In the embodiments shown in FIGS. 4(a) and 4(b), the gas discharge port 4a is directed downwardly in the lower chamber 1a, and the housing chamber 4 extends vertically. Accordingly, when the gas generator 3 is activated, the airbags 1C and 1D are first inflated vertically quickly. In the airbag 1C shown in FIG. 4(a), the gas flows into the middle chamber 1c from the gas discharge port 4c at a rear of the middle chamber 1c. Therefore, the middle chamber 1c is inflated forward quickly. In the airbag 1D shown in FIG. 4(b), when the occupant plunges into the inflated upper chamber 1b, a part of the gas in the upper chamber 1b flows into the middle chamber 1c through the gas discharge port 4c, thereby absorbing an impact applied to the occupant.

[0041] According to the invention, the seam 24 may extend diagonally, as shown in an airbag 1E in FIG. 7.

[0042] The embodiments described above are only examples of the invention and various modifications may be possible in the invention. For example, the invention may include three or more partitioning seams to form four chambers or more.

[0043] As described above, the present invention provides the airbag system that can be produced at a low cost. According to the invention, the airbag can be quickly inflated vertically.

[0044] While the invention has been explained with reference to the specific embodiments of the invention, the explanation is illustrative and the invention is limited only by the appended claims.