Seat structure having a side impact air bag apparatus

Abstract: In a seat structure having a side impact air bag apparatus, a seat back frame has side frames each provided at a corresponding widthwise direction side of a seat. An air bag accommodating concave portion is formed in one of the side frames which opposes a vehicle door such that the concave portion extends inward from an end portion of the seat back frame in the widthwise direction of the seat. The air bag accommodating concave portion accommodates an inflator and a folded air bag. A seat pad is provided for covering the seat back frame, and a seat surface layer is provided for covering the seat pad. The seat surface layer covers the air bag accommodating concave portion and the seat pad.

Description: BACKGROUND OF THE INVENTION Field of the Invention: The present invention relates to a seat structure having an air bag apparatus for a side impact (hereinafter referred to as a "side impact air bag apparatus"), and more particularly to a seat structure which has a side impact air bag apparatus at a side portion of a seat back frame. Description of the Related Art: A seat structure having a side impact air bag apparatus has been conventionally known, and documents JP-A-04050052 US-A-5,348,342, US-A-5,112,079, US-A-5,222,761, US-A-5,251,931, and US-A-5,498,030, disclose such a seat structure. Among them, document JP-A-04050052 discloses a seat structure in which a folded air bag is accommodated in a concave portion formed in a side portion of a seat back. FIGS. 7 and 8 show an example of such a seat structure having a side impact air bag apparatus. In the seat structure shown in FIG. 7, an air bag apparatus 74 is disposed within a side portion 72A of a seat back 72. As shown in FIG. 8, the air bag apparatus 74 has a box-like shape whose longitudinal direction coincides with the vertical direction of the vehicle, and is attached to a side frame (i.e., reinforcing member) 80 of a seat back frame 78 using screws 83. As shown in FIG. 7, a lid portion 82A is disposed opposite to the side frame 80 with respect to an air bag case 82. When the air bag 84 is expanded, the lid portion 82A opens outward in the widthwise direction of the seat (in the direction of arrow W in FIG. 7) around a hinge portion 82B formed at the rear end in the longitudinal direction of the vehicle. Moreover, upon opening of the lid portion 82A, a seat surface layer 86 is ruptured. However, the above-described seat structure having a side impact air bag apparatus has the following problems. (1) Since the air bag apparatus 74 is attached to the outer side surface 80A of the side frame 80 in the transverse direction of the vehicle, the overall width of the seat back 72 increases. (2) Since the air bag apparatus 74 projects from the side frame 80 further toward the rear of the vehicle than the seat back, the thickness of the side portion 72A of the seat back 72 in the longitudinal direction of the vehicle also increases. Accordingly, the effective room space of the vehicle decreases. Document WO-A-9607563 which was published on March 14, 1996 discloses a seat structure having a circular opening in one of the side frames into which an inflator accommodating portion of a side impact air bag apparatus is inserted. The inflator accommodating portion and the inflator accommodated therein extend perpendicularly to the side frame. Document JP-A-04050052 to which reference has already been made discloses also an embodiment of a seat structure which comprises the features summarized in the preamble of claim 1. The air bag accommodating concave portion of this known seat structure has a trapezoidal cross section and occupies a considerable space in the transverse direction of the vehicle as well as in the longitudinal direction of the vehicle. A seat structure comprising the features summarized in the preamble of claim 5 is known from that embodiment disclosed in document JP-A-04050052 which was already discussed with reference to Figures 7 and 8. SUMMARY OF THE INVENTION It is an object of the present invention to further develop the seat structures according to the preambles of claims 1 and 5 such that the overall width of the seat back can be decreased and, therefore, the interior room space of the vehicle can be increased. According to a first aspect of the invention, this object is achieved by the seat structure defined in claim 1. In the seat structure according to claim 1, both the overall width of the seat back and the thickness of the side portion of the seat back in the longitudinal direction of the vehicle can be decreased, and therefore the interior room space of the vehicle can be increased. Moreover, since a bracket for attachment of the air bag apparatus and an air bag case can be omitted, the assembly can be performed with improved workability. If the seat structure is designed according to claim 2, an air bag cover is formed by the portion surrounded by the generally U-shaped slit formed in the side pad portion of the seat pad. Also, since the lid portion of the air bag case can be omitted, the easiness of the assembly can be enhanced further. According to a second aspect of the invention, the above-mentioned object is also achieved by the seat structure defined in claim 5. In this seat structure, the inflator and the inflator accommodating portion are fitted into the inflator mounting opening. Accordingly, the interior room space of the vehicle can be increased. Moreover. the inflator can be supported with increased rigidity. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a horizontal cross-sectional view showing the side portion of a seat structure having a side impact air bag apparatus according to the a first embodiment of the present invention FIG. 2 is a perspective view of the seat back frame of the seat structure having a side impact air bag apparatus according to the first embodiment, as viewed diagonally from the front of the seat; FIG. 3 is a perspective view of the seat pad of the seat structure having a side impact air bag apparatus according to the first embodiment, as viewed diagonally from the front of the seat; FIG. 4 is a perspective view of a seat to which the seat structure having a side impact air bag apparatus according to the first embodiment is applied, as viewed diagonally from the front of the seat; FIG. 5 is a perspective view of the seat back frame of the seat structure having a side impact air bag apparatus according to a second embodiment of the present invention, as viewed diagonally from the rear of the seat; FIG. 6 is a horizontal cross-sectional view showing the side portion of the seat structure having a side impact air bag apparatus according to the second embodiment of the present invention; FIG. 7 is a horizontal cross-sectional view showing the side portion of a conventional seat structure having a side impact air bag apparatus; FIG. 8 is a perspective view of the seat back frame of the conventional seat structure having a side impact air bag apparatus, as viewed diagonally from the front of the seat; and FIG. 9 is a horizontal cross-sectional view showing the side portion of another conventional seat structure having a side impact air bag apparatus. DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. 1 and 4. As shown in FIG. 4, in a seat structure having a side impact air bag apparatus according to the first embodiment, a side impact air bag apparatus 14 having a box-like shape is disposed within a seat back 12 of a seat 10. More specifically, the air bag apparatus 14 is disposed within a side portion 12A formed at the outer side of the seat back 12 in the transverse direction of the vehicle such that the air bag apparatus 14 extends in the vertical direction. As shown in FIG. 2, a seat back frame 16 of the seat back 12 has a pair of side frames 18 and 20 each serving as a reinforcing member and disposed at a corresponding widthwise end of the seat back frame 16. The upper ends of the side frames 18 and 20 are connected to each other via an upper frame 22 which is formed of a tube material and is bent in a generally U-like shape. The edge portions of the side frames 18 and 22 located at the rear side of the seat are connected to each other via a plurality of seat wires 24. As shown in FIG. 1, at the forward end portion (i.e., the end portion in the direction F) of the side frame 18 located at the outer side in the transverse direction of the vehicle, there is formed a flange 18A which is bent inward in the widthwise direction of the seat (i.e., in the direction IN). Also, at the rear end portion (i.e., the end portion in the direction R) of the side frame 18, there is formed a flange 18B which is bent inward in the widthwise direction of the seat. At the central portion of the side frame 18 in the longitudinal direction of the vehicle is formed an air bag accommodating concave portion 26. This air bag accommodating concave portion 26 is formed by depressing the central portion of the side frame 18 toward the inside of the seat in a predetermined region extending in the longitudinal direction of the seat back. At the rear end of the air bag accommodating concave portion 26, the side frame 18 is further depressed toward the inside of the seat, thereby defining an inflator accommodating portion 26A. A folded air bag 28 is accommodated in the air bag accommodating concave portion 26, and a cylindrical inflator 30 is accommodated in the inflator accommodating portion 26A. Accordingly, the portion of the side frame 18 which forms the concave portion 26 serves as a bottom portion of an air bag case, and the air bag 28 is deployed by gas jetted from the inflator 30. As shown in FIG. 2, the air bag 28 is fixed to the side frame 18 by using fixing means such as, for example, two pieces of tape 32 and 34 provided at upper and lower portions of the side frame 18. These pieces of tape 32 and 34 are easily peeled off from the side frame 18 when the air bag 28 is deployed. As shown in FIG. 3, a U-shaped slit 38 is formed in a side pad portion 36A of a seat pad 36 which covers the seat back frame. The U-shaped slit 38 is formed such that the slit 38 faces the peripheral portion of the air bag accommodating concave portion 26 (see FIG. 1), and the rear side of the portion surrounded by the U-shaped slit 38 closer to the back of the seat is continuous with the side pad portion 36A. Accordingly, the portion surrounded by the slit 38, i.e., a lid portion 36B serves as a lid of the air bag case. When the air bag 28 is deployed, the lid portion 36B smoothly opens toward the outside of the seat. As shown in FIG. 1, a seat surface layer 40 covers the outer face of the seat pad 36. This seat surface layer 40 is made by sewing several covering sheets at seams 42, 44, 46, etc., serving as sewn portions. Among these seams, the seam 44 faces the front edge portion of the side pad portion 36A of the seat pad 36. Therefore, when the air bag 28 is deployed, the seam 44 is broken so that the seat surface layer 40 can be easily ruptured there. Next, the operation of the first embodiment will be described. In the seat structure having a side impact air bag apparatus according to the first embodiment, when the gas inflator 30 of the air bag apparatus 14 is operated upon occurrence of a side crash, gas is jetted from the gas inflator 30. As a result, the air bag 28 is deployed from the side portion 12A of the seat back 12 toward the front side of the seat, as indicated by an imaginary line in FIG. 1, so that the air bag 28 abuts a side portion of an occupant 40 on the seat 10. At this time, the lid portion 36B of the seat pad 36 is pressed by the air bag 28 so that it smoothly opens outward, as illustrated by an imaginary line in FIG. 1, and the seam 44 of the seat cover 40 is easily broken. Accordingly, the air bag 28 can be deployed quickly. In the seat structure having a side impact air bag apparatus according to the first embodiment, the inflator 30 and the folded air bag 28 are accommodated within the air bag accommodating concave portion 26, which is formed by depressing the side frame 18 inward in the widthwise direction of the seat, and the inflator 30 brand the air bag 28 are covered together with the seat pad 36 by the seat surface layer 40. Accordingly, the overall width of the seat back 12 becomes smaller compared to the case where an air bag apparatus is attached to the outer side surface of the side frame. This increases the room space in the vehicle. The seat structure of the present embodiment does not deteriorate the appearance of the seat 10, and can be applied to seats of small vehicles. Since the portion of the side frame 18 which forms the air bag accommodating concave portion 26 serves as the bottom portion of the air bag case and the lid portion 36B of the seat pad 36 serves as the lid portion of the air bag case, it is possible to eliminate a bracket for attaching, the air bag apparatus to the side frame and an air bag case which have been used in conventional structures. Accordingly, the number of required parts can be decreased, and the assembly can be performed in a facilitated manner. Next, a seat structure having a side impact air bag apparatus according to a second embodiment of the present invention will be described with reference to FIGS. 5 and 6. The members identical to those of the first embodiment are denoted by the same reference numerals, and their descriptions will be omitted. As shown in FIG. 5. In the seat structure having a side impact air bag apparatus 96 according to the second embodiment, an inflator mounting opening 94 is formed in a side frame (reinforcing member) 92 of the seat back frame 16 such that the opening 94 runs in the longitudinal direction of the seat back. An electrical wire 50 connected to an inflator 48 is led to the inside of the side frame 92 through the inflator mounting opening 94. As illustrated in Fig. 6, the inflator 48, together with an inflator accommodating portion 98 which projects toward the rear surface side of the air bag apparatus 96, is inserted in the inflator mounting opening 94 so as to be nipped and so as project further toward the vehicle transverse direction inner side than the side frame 92. The air bag apparatus 96 is directly fixed to the side frame 92 by a plurality of bolts 52, which serve as the fixing means, being inserted from the seat back frame 16 transverse direction outer side into through-holes provided in the air bag apparatus 96 and the side frame 92, and by the plurality of bolts 52 being screwed with nuts 54 which also serve as the fixing means. Further, the air bag apparatus 96 as well as the seat pad 36 are covered by the seat surface layer 40. When the air bag 28 is expanded, a seam 100, which is located in the vicinity of the lid portion 36B and serves as a sewn portion, is easily broken. As described above, in the seat structure having a side impact air bag apparatus according to the second embodiment of the present invention, the inflator 48 is fitted into the inflator mounting opening 94 such that the inflator 48 project inward from the side frame 92 in the transverse direction of the vehicle, and the electrical wire 50 of the inflator 48 is led to the inside of the side frame 92 through the inflator mounting opening 94. Accordingly, it is unnecessary to separately provide a cover for protecting the electrical wire 50, unlike the conventional structure shown in FIG. 9, in which a cover 152 is separately provided in the side portion 72A of the seat back 72 so as to protect the electrical wire 50. In FIG. 9, the members identical to those shown in FIG. 7 are denoted by the same reference numerals, and their descriptions will be omitted. Accordingly, a portion 12B rearwardly projecting from the side portion 12A of the seat back 12 as indicated by an imaginary line in FIG. 6 can be made smaller, so that the freedom in designing can be increased. In addition, since the number of required parts decreases, the assembly can be performed more efficiently. Since the inflator 48 is mounted such that it is fitted into the inflator mounting opening 94 and projects inward from the side frame 92 in the transverse direction of the vehicle, the inflator 48 can be supported with increased rigidity. The present invention has been described in detail with reference to the specific embodiments thereof. However, the present invention is not limited to those embodiments, and may be practiced in various manners without departing from the scope of the present invention.

Claims: A seat structure having a side impact air bag apparatus (14) comprising a folded air bag (28) and an inflator (30) for inflating the air bag (28), said seat structure further comprising: a seat back frame (16) having a pair of side frames (18, 20) each provided at a corresponding widthwise direction side of a seat back (12), an air bag accommodating concave portion (26) for accommodating the folded airbag (28), the air bag accommodating concave portion (26) being disposed in that one of said side frames (18, 20) which opposes a vehicle door and being formed by a depressed portion of the one of said side frames (18), said depressed portion being depressed toward the inside of the seat back (12) in the widthwise direction thereof and having a bottom, a seat pad (36) for covering the seat back frame (16), and a seat surface layer (40) for covering the seat pad (36) and the air bag accommodating concave portion (26), characterized in that a portion of the bottom of said air bag accommodating concave portion (26) is further depressed toward the inside of the seat back (12) in the widthwise direction thereof for defining an inflator accommodating portion (26A) accommodating said inflator (30). A seat structure according to Claim 1, wherein said seat pad (36) has a substantially U-shaped slit (38) formed in a side pad portion (36A) of said seat pad (36) at a position opposing said air bag accommodating concave portion (26), said substantially U-shaped slit (38) including a base portion and two parallel leg portions forming a substantially U-shape, the leg portions extending from the base portion toward the rear of the seat back (12). A seat structure according to Claim 1 or 2, further comprising: a fixing means (34) which is provided on said one of said side frames (18) for fixing said folded air bag (28) to said one of said side frames (18). A seat structure according to Claim 3, wherein said fixing means (34) is an elongated member. A seat structure having a side impact air bag apparatus (96) comprising a folded air bag (28), an inflator (48) for inflating the air bag (28) and an inflator accommodating portion (98) for accommodating the inflator (48), wherein the inflator accommodating portion (98) projects toward the rear surface side of the side impact air bag apparatus (96), said seat structure further comprising: a seat back frame (16) having a pair of side frames (92) each provided at a corresponding widthwise direction side of a seat back (12), wherein the air bag apparatus (96) is disposed on that one of said side frames (92) which opposes a vehicle door, a seat pad (36) for covering the seat back frame (16), and a seat surface layer (40) for covering the seat pad (36) and the air bag apparatus (96), characterized in that an inflator mounting opening (94) which extends in the longitudinal direction of said seat back (12) is formed in said one of said side frames (92), and in that said inflator accommodating portion (98) and the inflator (48) are inserted into said inflator mounting opening (94) such that they project from said one of said side frames (92) toward the inside of the seat back (12) in the widthwise direction thereof. A seat structure according to Claim 5, wherein said seat pad (36) has a substantially U-shaped slit (38) formed in a side pad portion (36A) of said seat pad (36) at a position opposing said air bag apparatus (96), said substantially U-shaped slit (38) including a base portion and two parallel leg portions forming a substantially U-shape the leg portions extending from the base portion toward the rear of the seat back (12). A seat structure according to Claim 5 or 6, further comprising: a fixing means (52,54) for fixing said air bag apparatus (96) to said one of said side frames (92). A seat structure according to Claim 7, wherein said fixing means is a screwing means (52,54). A seat structure according to Claim 8, wherein said screwing means comprises a bolt (52) and a nut (54). A seat structure according to one of claims 5 to 9, wherein said inflator mounting opening (94) is provided so as to allow an electrical wire (50) connected to said inflator (48) to be led toward the inside of said side frame (92) in the widthwise direction of the seat back (12). A seat structure according to one of claims 1 to 10, wherein said seat surface layer (40) has a sewn portion (44) and said sewn portion is broken upon expansion of said air bag (28). A seat structure according to one of claims 1 to 11, wherein said seat back frame (16) has an upper frame (22) for connecting said side frames (18,20;92). A seat structure according to Claim 12, wherein said upper frame (22) is a pipe-shaped member. A seat structure according to one of claims 1 to 13, wherein said seat back frame (16) has a connecting member (24) for connecting the rear end portions of said side frames (18,20;92). A seat structure according Claim 14, wherein said connecting member is formed by a plurality of wires (24) arranged in the longitudinal direction of said side frames (18,20;92)

Inventors: HASEGAWA YASUNORI, KAJIYAMA TOSHIHIKO, KATO HISAAKI, OHNO MITSUYOSHI, SEKIZUKA MAKOTO, HASEGAWA, YASUNORI, KAJIYAMA, TOSHIHIKO, KATO, HISAAKI, OHNO, MITSUYOSHI, SEKIZUKA, MAKOTO
Applicants: TOYOTA MOTOR CO LTD, TOYOTA JIDOSHA KABUSHIKI KAISHA
Application year: 1996
Main classification: B60R21
IPC codes: B60R21, B60N2