Passenger-side airbag device

Abstract: A passenger-side airbag device has an airbag 11 in a container 12. The passenger-side airbag device can smoothly deploy the airbag 11 toward an occupant in a passenger seat not in a direction perpendicularly to a panel surface of an instrument panel in case where the airbag device is installed in the instrument panel so that the airbag is hard to collide with the windshield during its deployment. The airbag 11 is inflatable by an inflator 13. The container 12 has a lid 14 covering the upper surface of the container 12. Among peripheral portions of the airbag 11, a windshield-side peripheral portion 11c has a longer length than that of a passenger-side peripheral portion 11b. When the airbag expands, the passenger-side peripheral portion 11b is tensioned first, so a bulk portion 11a is pushed out and expands toward the occupant.

Description: Field of the invention and related art statement The present invention relates to a passenger-side airbag device installed in an instrument panel in front of a passenger's seat of a vehicle including an automobile. Apassenger-side airbag device comprises a container installed in an instrument panel in front of a passenger's seat of a vehicle, a gas generator for inflating an airbag, an airbag accommodated in the container and having a gas inlet for receiving gas, and a lid covering the container. The gas generator is actuated to supply gas into the airbag when the vehicle comes into collision, and the airbag starts to expand. After the airbag starts expanding, the lid is pushed by the airbag and opens whereby the airbag inflates into a vehicle cabin. The airbag has a gas inlet for receiving gas from the gas generator. The periphery of the gas inlet is connected to the container. The airbag is folded, as described in JPA 4-100754, by first tucking a left side and a right side of the airbag therein toward the center to make the airbag a semi-folded body of which the width along the lateral direction is small, then folding the semi-folded body into bellows-like configuration to form a bulk portion, and accommodating the bulk portion in the container. Hereinafter, the folding manner of the airbag of JPA 4-100754 will be described with reference to Figs. 6 through 12. Fig. 6 is a perspective view of an airbag 1 in its flat-spreaded state and a sub-container 2. The airbag 1 has short sides 1b which are straight, long right and left sides 1a which are curved in an arc shape, a gas inlet 3 for receiving gas from an inflator which is formed at a center of a rear face opposite to a front face to confront an occupant, and vent holes 4 for buffering when the occupant collides with the inflated airbag. Areference numeral 5 designates a rivet hole. The sub-container 2 is provided with holes 6 formed at a bottom thereof through which gas from the inflator passes into the airbag 1. The airbag 1 is flat-spreaded in the state that the sub-container 2 is connected to the airbag 1 as shown in Fig. 7. From this state, the long sides 1a are tucked in the airbag 1 in such a manner that the width of the airbag 1 becomes slightly smaller than the width of the sub-container, thereby forming a semi-folded body as shown in Fig. 8 and Fig. 9 which is a sectional view taken along a line IX-IX of Fig. 8. Then, the semi-folded body 1 is folded many times in bellows like configuration so as to crease pleat lines 7 extending perpendicularly to straight sides la' of the semi-folded body as shown in Fig. 10 which is a side view taken along a line X-X of Fig. 8. As shown in Fig. 11, the folded portions are piled up and accommodated in the sub-container 2 (Fig. 12). Though the folded airbag is accommodated in the sub-container 2 and the sub-container 2 is accommodated in a main container (not shown) in JPA 4-100754, the folded airbag is sometimes directly accommodated in the main container without the sub-container. In the conventional passenger-side airbag device, a bulk body of the airbag is formed by folding the airbag 1. The periphery of the gas inlet 3 of the airbag 1 is connected to the sub-container 2. Among portions around the periphery of the gas inlet 3 of the airbag 1, a windshield-side portion 1A, which is connected to a windshield side 2A of the sub-container 2, has the same length as that of an occupant-side portion 1B, which is connected to an occupant side 2B of the sub-container 2. Therefore, when the airbag 1 is about to be inflated (deployed) with gas from the inflator, the airbag 1 starts to expand in a direction perpendicular to the upper surface of the sub-container 2 as shown by arrow S of Fig. 12. Since the sub-container 2 is disposed such that the upper surface thereof is parallel to a panel surface of the instrument panel, the airbag 1 starts to expand in a direction perpendicular to the panel surface of the instrument panel. When the conventional passenger-side airbag device, of which the airbag will start to expand in the direction perpendicular to the panel surface of the instrument panel, is installed in a portion of the upper surface side of the instrument panel, the airbag collides with the windshield during its expansion so that the airbag is subjected to forces such as friction from the windshield. Because of this situation, it is necessary, for inflating sufficiently the airbag, to supply high-pressure gas into the airbag to overcome the forces such as friction. Therefore, a gas generator of large capacity is required. From US-A-5,496,056 a passenger-side airbag device according to the preamble of claim 1 is known. The passenger-side airbag device comprises a container installed in an instrument panel in front of a passenger seat, an airbag accommodated in the container and having a gas inlet for receiving gas, and a gas generator for inflating the airbag. The airbag has a folded bulk portion and a peripheral area between the bulk portion and the gas inlet. The bulk portion and the peripheral area comprise a lower pleat and an upper pleat which are laid on one another, the peripheral area between the bulk portion and the container with the upper pleat and the lower pleat being folded in the form of a loop. From EP 0 957 007 A2, which is prior art under Article 54(3), (4) EPC, a passenger-side airbag device is known, which comprises a gas generator for inflating an airbag, and an airbag accommodated in a container and having a gas inlet for receiving gas, a periphery of the gas inlet being connected to the container. The airbag has a bulk portion formed by folding in a bulk and a peripheral area between the bulk portion and the gas inlet, the length of a windshield-side peripheral portion of the peripheral area connecting a windshield side of the container and the bulk portion being longer than the length of an occupant-side peripheral portion of the peripheral area connecting an occupant side of the container and the bulk portion. In addition, the windshield-side peripheral portion of the peripheral area of the airbag is folded several times between the bulk portion and the windshield side of the container, while the occupant-side peripheral portion of the peripheral area of the airbag is disposed between the occupant side of the container and the bulk portion without any folded portion or slack. Object and summary of the invention It is an object of the invention to provide a passenger-side airbag device in which it is unlikely that an airbag collides with a windshield during its deployment even if the airbag device is disposed in an upper-side portion of an instrument panel. According to the present invention, this object is achieved by a passenger-side airbag device as defined in claim 1. Furthermore, a method for manufacturing such a passenger-side airbag device as defined in claim 3 is provided. The dependent claims define preferred and advantageous embodiments of the present invention. A passenger-side airbag device of the present invention comprises a container installed in an instrument panel in front of a passenger seat, a gas generator for inflating an airbag, and an airbag accommodated in the container and having gas inlet for receiving gas. The periphery of the gas inlet is connected to the container. The airbag has a bulk portion formed by folding in a bulk and a peripheral area between the bulk portion and the gas inlet. The length L 1 of the peripheral area along a direction connecting the windshield side of the container and the bulk portion is longer than the length L 2 of the peripheral area along the direction connecting the occupant side of the container and the bulk portion, the windshield-side peripheral portion of the peripheral area being folded several times between the bulk portion and the windshield side of the container, while the occupant-side peripheral portion of the peripheral area is disposed between the occupant side of the container and the bulk portion without any folded portion or slack, the length of the windshield-side peripheral portion being 1.5 times or more the length of the occupant-side peripheral portion. When a vehicle, in which the passenger-side airbag device is installed in the upper surface of the instrument panel, comes into collision and the gas generator is actuated, the airbag pushes outwardly the lid to open the lid and starts to expand into the vehicle cabin. In this case, the bulk portion is moved to the upper side of the instrument panel and then the bulk portion is gradually inflated. Since the length L 1 of the windshield-side peripheral area is longer than the length L 2 of the occupant-side peripheral area, the bulk portion is moved in a direction apart from the windshield not in a direction perpendicular to the panel surface of the instrument panel. As a result, the airbag during its deployment is hard to collide (or does not collide at all) with the windshield. It is preferable that the length L 1 is 1.5-4 times, particularly 1.5-3 times, more particularly 2-2.5 times as long as the length L 2 . According to the present invention, the airbag is preferably folded by first tucking a left side and a right side of the airbag therein toward the center to make the airbag a semi-folded body having a smaller width along the lateral direction, and then concavely folding a portion, to be confronting an occupant in the passenger seat, of the semi-folded body. It should be understood that the right and left of the airbag means the right and left from the view point of the occupant when the passenger-side airbag device is installed in the vehicle and the occupant is oriented toward the front of the vehicle. Brief description of the drawings Fig. 1 is a vertical sectional view of a passenger-side airbag device according to an embodiment; Fig. 2 is a vertical sectional view of the passenger-side airbag device according to the embodiment in the process of the expansion of an airbag thereof; Fig. 3 is a vertical sectional view of the passenger-side airbag device according to the embodiment in the process of the expansion of the airbag; Fig. 4 is a vertical sectional view of the passenger-side airbag device according to the embodiment in the process of the expansion of the airbag; Fig. 5 is a longitudinal sectional view of a vehicle in which the passenger-side airbag device according to the embodiment is installed; Fig. 6 is a perspective view showing a conventional example; Fig. 7 is a plan view showing the conventional example; Fig. 8 is an explanatory view of a conventional airbag folding method; Fig. 9 is a sectional view taken along a line IX-IX of Fig. 8; Fig. 10 is an explanatory view of the conventional airbag folding method; Fig. 11 is an explanatory view of the conventional airbag folding method; Fig. 12 is an explanatory view of the conventional airbag folding method; Fig. 13 is an explanatory view showing an airbag folding method of the present invention; Fig. 14 is a sectional view of a passenger-side airbag device according to another embodiment; and Fig. 15 is a sectional view of a passenger-side airbag device according to further another embodiment. Preferred Embodiments Hereinafter, embodiments of the present invention will be described with reference to attached drawings. Fig. 1 is a vertical sectional view (taken along the longitudinal direction of a vehicle) of a passenger-side airbag device according to an embodiment, Fig. 2, Fig. 3, and Fig. 4 are sectional views of the passenger-side airbag device in the process of the expansion of an airbag thereof, and Fig. 5 is a longitudinal sectional view of the vehicle, in which the passenger-side airbag device is installed, in the process of expansion of the airbag. Fig. 13 is a perspective view of the airbag in the process of the folding. The passenger-side airbag device 10 comprises an airbag 11, a container 12 accommodating the airbag 11, an inflator 13 for generating gas for inflating the airbag 11, and a lid 14 covering an upper opening of the container 12. The airbag is folded, in the same manner as described with regard to Figs. 6 through 12, by first tucking left and right sides, i.e. longer sides, of the airbag therein toward the center to make the airbag a semi-folded body 11' which has a longer side along the longitudinal direction of the vehicle, then folding the semi-folded body 11' into the configuration as shown in Fig. 13 to form a bulk portion 11a, and accommodating the bulk portion 11a in the container 12. In folding the airbag to form the bulk portion 11a from the semi-folded body 11', an occupant-confronting portion of the airbag is folded concavely (i.e. folded back toward the occupant-confronting surface). In this embodiment, as apparent from Fig. 1 through Fig. 13, the sub-folded body 11' are folded in a roll. The airbag 11 is folded after the periphery of the gas inlet thereof is connected to the container 12. Among the peripheral portions surrounding the gas inlet of the airbag 11, a windshield-side peripheral portion 11c is longer than an occupant-side peripheral portion 11b. That is, the windshield-side peripheral portion lie is folded several times between the bulk portion 11a and a windshield-side edge of the container 12, while the occupant-side peripheral portion 11b is disposed between an occupant-side edge of the container 12 and the bulk portion 11a without any folded portion or slack. The lid 14 has legs 14a, 14b on occupant-side and windshield-side portions, respectively. The legs 14a, 14b are fixed to the container 12. The leg 14a has a fragile root so that the root of the leg 14a is broken when the inflator 13 is actuated to generate gas. As a result of this, the lid 14 opens to stand up toward the windshield 20 as shown in Fig. 2. The airbag device 10 is installed in the vehicle so that the lid 14 is flush with an instrument panel 30. In the passenger-side airbag device 10 as structured above, once the vehicle comes into collision, the inflator 13 is actuated to generate gas. The gas inflates the airbag 11 which in turn pushes the lid 14 so that the lid 14 opens as shown in Fig. 2. Therefore, the airbag 11 starts to expand toward a vehicle cabin. In this case, since the windshield-side peripheral portion lie of the airbag 11 is longer than the occupant-side peripheral portion 11b, the airbag continuously expands in such a manner that the bulk portion 11a is pushed out toward the occupant as shown by arrow A of Fig. 3. That is, as the airbag 11, which received gas from the inflator, starts to expand outside the container 12, the occupant-side peripheral portion 11b is tensioned but the windshield-side peripheral portion 11c has still sufficient slack. Consequently, the bulk portion 11a is tensioned to move toward the occupant side so that it is about to expand toward the occupant not in a direction perpendicularly to the upper surface of the container 12. As the airbag 11 further expands as shown in Fig. 4 and Fig. 5, the windshield-side peripheral portion 11c has no more slack and the bulk portion 11a starts to deploy like releasing the roll in the direction of arrow B of Fig. 4. Finally, the airbag 11 expands in the final deployment configuration shown by numeral 11" of Fig. 5. As dearly shown in Fig. 4 and Fig. 5, since the airbag 11 expands toward the occupant side not in the direction perpendicularly to the panel surface of the instrument panel 30, the airbag 11 does not strongly collide with the windshield 20 during its expansion. Therefore, the airbag 11 can be smoothly and largely deployed into the vehicle cabin without being subjected to force such as friction from the windshield 20. Therefore, even when the inflator 13 employed is small in capacity of both the amount and pressure of generated gas, the airbag 11 can be sufficiently quickly deployed. Since the friction from the windshield 20 is small, the airbag 11 can be made of fabric having low strength or thin fabric. Fig. 14 and Fig. 15 are sectional views illustrating suitable dimensions of an airbag to be employed according to the present invention. In Figs. 14 and 15, a passenger-side airbag device 100, 200 installed in the instrument panel 30 is accommodated in a container 120, 220 in a state that an airbag 110, 210 is folded in the same manner as the aforementioned embodiment. As an inflator 130, 230 is actuated, the airbag 110, 210 expands in such a manner that a bulk portion 110a, 210a is pushed out toward the occupant. In Fig. 14, the inflator 130 is disposed beneath of the bulk portion 110a in the container 120. In Fig. 15, the inflator 230 is positioned on a side of the bulk portion 210a (at the windshield 20 side) in the container 220. In each of the passenger-side airbag devices 100, 200, the ratio of the length L 1 of the windshield-side peripheral portion and the length L 2 of the occupant-side peripheral portion of the airbag 110, i.e. L 1 /L 2 , is preferably in a range between 1.5 and 4, particularly between 1.5 and 3, more particularly between 1.5 and 2.5. It is preferable that L 2 is substantially the same as dimension Q (the effective depth of the container) in the drawings. In addition, it is preferable that L 1 is substantially the same as the sum of dimension P (the width of the opening of the container along a direction of opening the lid) and Q, i.e. P + Q. When L 2 is substantially 0, L 1 is preferably 0.5-2 times, particularly 0.5-1.5 times, more particularly 1-1.5 times, as long as the dimension P. As described above, in the passenger-side airbag device according to the present invention installed in the upper surface of the instrument panel, the airbag can expand toward the occupant not in the direction perpendicularly to the panel surface of the instrument panel. Accordingly, the airbag during the expansion is hard to collide with the windshield so that the airbag can be rapidly deployed in the vehicle cabin. In addition, a gas generator of small capacity can be employed and the airbag can be made of thin fabric.

Claims: A passenger-side airbag device (10, 100, 200) comprising: a container (12, 120, 220) installed in an instrument panel (30) in front of a passenger seat; a gas generator (13, 130, 230) for inflating an airbag (11, 110, 210); and an airbag (11, 110, 210) accommodated in the container (12, 120, 220) and having a gas inlet for receiving gas, a periphery of the gas inlet being connected to the container; wherein the airbag (11, 110, 210) has a bulk portion (11a, 110a, 210a) formed by folding in a bulk and a peripheral area between the bulk portion and the gas inlet; and wherein a length (L 1 ) of a windshield-side peripheral portion (11c) of the peripheral area connecting a windshield side of the container (12, 120, 220) and the bulk portion (11a, 110a, 210a) is longer than a length (L 2 ) of an occupant-side peripheral portion (11b) of the peripheral area connecting an occupant side of the container (12, 120, 220) and the bulk portion (11a, 110a, 210a), the length (L 1 ) of the windshield-side peripheral portion (11c) being 1.5 times or more as long as the length (L 2 ) of the occupant-side peripheral portion (11b), characterized in that the windshield-side peripheral portion (11c) of the peripheral area of the airbag (11, 110, 210) is folded several times between the bulk portion (11a, 110a, 210a) and the windshield side of the container (12, 120, 220), while the occupant-side peripheral portion (11b) of the peripheral area of the airbag (11, 110, 210) is disposed between the occupant side of the container (12, 120, 220) and the bulk portion (11a, 110a, 210a) without any folded portion or slack. A passenger-side airbag device as claimed in claim 1, characterized in that the length (L 1 ) of the windshield-side peripheral portion (11c) of the peripheral area of the airbag (11, 110, 210) is substantially the same as the sum of a depth (Q) of the container (12, 120, 220) and a width (P) of an opening of the container (12, 120, 220), and the length (L 2 ) of the occupant-side peripheral portion (11b) of the peripheral area of the airbag (11, 110, 210) is substantially the same as the depth (Q) of the container (12, 120, 220), the length (L 1 ) of the windshield-side peripheral portion (11c) of the peripheral area of the airbag (11, 110, 210) being 0.5-2 times as long as the width (P) of the opening of the container (12, 120, 220) if the length (L 2 ) of the occupant-side peripheral portion (11b) of the peripheral area of the airbag (11, 110, 210) is substantially 0. A method of manufacturing a passenger-side airbag device (10, 100, 200) as claimed in claim 1 or claim 2, wherein the periphery of the gas inlet of the airbag (11, 110, 210) is connected to the container (12, 120, 220), wherein the airbag (11, 110, 210) is then folded by first tucking a left side and a right side of the airbag therein toward the center to make the airbag a semi-folded body (11') having a smaller width along the lateral direction, and wherein a portion of the semi-folded body (11') confronting an occupant on the passenger seat is then folded concavely, characterized in that the periphery of the gas inlet of the airbag (11, 110, 210) is connected to the container (12, 120, 220) and the airbag (11, 110, 210) is folded such that the windshield-side peripheral portion (11c) of the peripheral area of the airbag (11, 110, 210) is folded several times between the bulk portion (11a, 110a, 210a) and the windshield side of the container (12, 120, 220), while the occupant-side peripheral portion (11b) of the peripheral area of the airbag (11, 110, 210) is disposed between the occupant side of the container (12, 120, 220) and the bulk portion (11a, 110a, 210a) without any folded portion or slack, the length (L 1 ) of the windshield-side peripheral portion (11c) being 1.5 times or more as long as the length (L 2 ) of the occupant-side peripheral portion (11b). A method of manufacturing a passenger-side airbag device as claimed in claim 3, characterized in that the semi-folded body (11-) is folded in a roll.

Inventors: IGAWA TADAHIRO, IGAWA, TADAHIRO, Igawa, Tadahiro Takata Corporation Echigawa Plant
Applicants: TAKATA CORP, TAKATA CORPORATION
Application year: 1998
Main classification: B60R21
IPC codes: B60R21