Side air bag apparatus of vehicle

Abstract: An air bag main body (10) is arranged along an inner side of an occupant room extending from a pillar to a side roof rail in its folded state and capable of being deployed downward. An inflator (11) ejects gas for inflating the air bag main body (10) so as to deploy the air bag main body downward. An upper end portion (11a) of the inflator (11) is preferably positioned somewhat lower than the head position of a normal occupant. A gas communication pipe (12) for introducing the gas from the inflator (11) to the air bag main body (10) is capable of being deformed owing to an excessive input from its external portion.

Description: The present invention relates to side air bag apparatus of a vehicle, and more particularly to side air bag apparatus for restraining a head portion or the like of an occupant at a time of a side collision of a vehicle. As side air bag apparatus of a vehicle there is a structure provided along a side roof rail, which is arranged in a portion corresponding to a head portion of an occupant, in a vehicle body. EP 841221 A discloses side air bag apparatus of a vehicle according to the preamble of claim 1. In accordance with a consideration of inventors of the present invention, there is a case that the side air bag apparatus is structured such that a bag-like air bag main body is provided between a side roof rail and a garnish covering the side roof rail in a folded state thereof. In the case mentioned above, an end portion of the air bag main body is connected to an inflator arranged between a pillar and a resin pillar garnish covering the pillar at the side of an occupant room. Then, the structure is made such that at the time of a side collision, gas is injected into the air bag main body from the inflator so as to downward inflate and deploy the air bag main body in a curtain shape, thereby restraining so as to protect the head portion of the occupant. In this case, since the inflator arranged at the pillar side is structured so as to inject the gas due to a reaction of a chemical agent therewithin or the like, rigidity of the inflator itself is increased so as to resist against pressure thereof. Accordingly, in order to more effectively absorb impact energy applied to the head portion of the occupant, there can be considered a structure that a plurality of ribs are formed on a back surface of a resin pillar garnish covering the inflator and the ribs are deformed in the case that the head portion of the occupant is brought into contact with a portion of the pillar garnish corresponding to the inflator. However, in the structure mentioned above, since it is necessary to form a plurality of ribs on the back surface of the pillar garnish covering the pillar at the side of the occupant room , a clearance between the inflator and the pillar garnish is increased correspondingly. Accordingly, the pillar garnish protrudes to the inner side of the occupant room, thereby reducing the occupant room interior space. An object of the present invention is to provide a side air bag apparatus of a vehicle which has no necessity of forming a plurality of ribs on a back surface of a pillar garnish or the like and can well secure an occupant room interior space, and which, in particular, effectively prevents the head of the occupant from interfering with the inflator. The present invention provides side air bag apparatus as set forth in claim 1. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a side view showing a main structure of an inner portion of an occupant room to which a side air bag apparatus of a vehicle in accordance with an embodiment of the present invention is mounted; Fig. 2 is an enlarged side view showing a portion near a rear pillar in accordance with the embodiment; Fig. 3 is a cross-sectional view showing an inflator and a pipe member in accordance with the embodiment; Fig. 4 is a cross-sectional view taken along a line IV-IV in Fig. 1; and Fig. 5 is a cross-sectional view taken along a line V-V in Fig. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A description will be in detail give below of an embodiment of a side air bag apparatus of a vehicle in accordance with the present invention with reference to Figs. 1 to 5. In this case, an arrow FR in the drawings denotes a front direction of a vehicle V, an arrow RR denotes a rear direction of the vehicle V, an arrow UPR denotes an upper direction of the vehicle V, and reference symbol R denotes an occupant room. As is representatively shown in Fig. 1 viewing an upper portion of the vehicle V as to an inner side of the occupant room R, reference numeral 1 denotes a front pillar, reference numeral 2 denotes a center pillar, and reference numeral 3 denotes a rear pillar which extends rearwardly downward from a side roof rail 4. The side roof rail 4 has a closed cross-sectional structure along a longitudinal direction and is formed at upper portions of the respective pillars 1, 2, and 3. As is in detail shown in Fig. 4, the side roof rail 4 is constituted by a rail outer panel 6 and a rail inner panel 5. An end portion of a roof panel 7 is bonded to an upper end portion of the side roof rail 4. A weather strip 8 for securing sealing performance with respect to a door (not shown) is mounted to a lower end portion of the side roof rail 4. A cover 9 formed in a substantially C shape and having a lower end portion close to the rail inner panel 5 is provided on an upper portion of the rail inner panel 5. A bag-like air bag main body 10 is received within the cover 9 in a folded state. An upper portion of the air bag main body 10 is commonly fastened to the rail inner panel 5 by a bolt 19 in a mounting portion P of the cover 9. A predetermined number of the mounting portions P are provided in a longitudinal direction. As shown in Figs. 1 and 2, a rear end portion 10a of the air bag main body 10 is formed in a narrow cylindrical shape so as to be protruded rearward from cover 9, and is connected to an inflator 11 generating a combustion gas for inflating the air bag main body through a metal pipe member 12 corresponding to a gas communication member. With respect to the side roof rail 4, as shown in Fig. 4, the cover 9 receiving the air bag main body 10 is covered by a roof side trim 13 at the side of the occupant room R. An end portion of the roof side trim 13 is connected to a head lining 14. With respect to the rear pillar 3, as shown in Figs. 1 and 5, the pipe member 12 and the inflator 11 are covered by another pillar garnish 15. The inflator 11 is formed in a rigid metal cylindrical shape, and fixed to a pillar inner panel 16 in a state of being aligned with the rear pillar 3 in a longitudinal direction thereof. The inflator is arranged so that an upper end portion thereof is positioned below a head portion H of the occupant. In this case, the "occupant" corresponds to a size of AF05 to AM95 percentile in an SAE mannequin. In particular, as shown in Fig. 2, the inflator 11 is arranged so that the upper end portion 11a thereof is positioned below a height h of eyes of the head portion H of the occupant, and is fixed to a position overlapping with the upper portion of a seat back 17 in a side view of the vehicle V. Here, a more detailed description will be given of the pipe member 12 corresponding to the gas communication member in accordance with the present embodiment. The pipe member 12 arranged between the rear end portion 10a of the air bag main body 10 and the inflator 11 is made of a metal, formed in a cylindrical shape and curved so as to smoothly connect the air bag main body 10 positioned at the side of the side roof rail 4 and the inflator 11 positioned at the side of the rear pillar. As shown in Fig. 3, the pipe member 12 has a portion formed in a necked shape that portions except both end portions, that is, a substantially whole portion thereof is contracted so as to have a diameter d smaller than that of the inflator 11, that is, a necked portion. The rear end portion 10a of the air bag main body 10 is connected to a front end portion 12a of the pipe member 12 by a metal fitting 18, and an opening of the upper end portion 11a of the inflator 11 is engaged with a rear end portion 12b. The diameter d of the pipe member 12, that is, a necking amount d can be optimally selected in correspondence to a shape, a volume, a folded way and the like of the connected air bag main body 10. That is, it is possible to control an injection characteristic of a combustion gas of the inflator by suitably tuning the necking amount d of the pipe member 12. Accordingly, even in the case of employing various kinds of air bag main bodies different in the shape, the volume,and the folded way, it is possible to correspond to the case only by modifying the pipe member 12 to a structure having a necking amount corresponding thereto, so that it is not necessary to replace the inflator 11 itself. The pipe member 12 is arranged between the air bag main body 10 and the inflator 11 and at the position just corresponding to the head portion H of the occupant. The pipe member 12 employs a metal cylindrical shape in the same manner as that of the inflator 11; however, in comparison with the inflator 11, structured so as to have a high rigidity so that gunpowder for the combustion gas can be stably sealed for a long time and a combustion gas having a high temperature and a high pressure can be injected in a predetermined direction, the pipe member 12 is structured so as to have a low rigidity and indicate a mechanical characteristic of capable of effectively deforming due to an excessive input from a side portion. Since the mechanical characteristic of the pipe member 12 mentioned above is based on an essential function that the pipe member 12 introduces the combustion gas having an injecting direction determined by the inflator 11 to the air bag main body 10, attention is paid to the matter that the rigidity itself can be relatively made lower as far as no substantial influence is given to the essential function. As is representatively shown in Fig. 5, with respect to the rear pillar 3, ribs or the like are not formed on the back surface in the pillar garnish 15 covering the pipe member 12, and a clearance C between the pipe member 12 and the pillar garnish 15 is set to be very small. Next, a description will be in detail given of an operation in the side air bag apparatus in accordance with the present embodiment having the structure mentioned above. At first, in the case that a sensor (not shown) detects a side collision of the vehicle, the combustion gas is correspondingly injected from the inflator 11 and is fed to the air bag main body 10 through the pipe member 12. At this time, since the pipe member 12 is made of a metal, the temperature of the combustion gas is correspondingly reduced and an influence due to excessive heat applied to the air bag main body 10 can be restricted. Next, when the combustion gas flows into the air bag main body 10, the air bag main body 10 starts inflating within the cover 9. In this case, since the cover 9 is structured such that only the upper end portion thereof is mounted to the rail inner panel 5, the cover starts opening around the upper end portion corresponding to a hinge when the air bag main body 10 inflates within the cover 9. At the same time, the air bag main body 10 develops downward from a portion between the lower end portion of the cover 9 and the rail inner 6 so as to form a curtain shape. Next, the air bag main body 10 developed so as to form a curtain shape can restrain so as to protect the head portion H of the occupant moving forward. Further, in addition, even in the case that the head portion H of the occupant is brought into contact with the pillar garnish 15 of the rear pillar 3 in place of the air bag main body 10 developed so as to form a curtain shape, the pipe member 12 arranged there is constructed by an easily deforming member having a low rigidity, so that impact energy can be effectively absorbed due to deformation of the pipe member 12. As mentioned above, in the side air bag apparatus in accordance with the present embodiment, since the structure is made such that the pipe member 12 is provided and a high pressure gas is introduced to the air bag main body 10 by the pipe member 12, ribs are not provided on the back surface of the pillar garnish 15. Accordingly, it is possible to reduce the clearance C between the pipe member 12 and the pillar garnish 15 so as to deploy the space of the occupant room R. Further, since the inflator 11 having a high rigidity is in a state that the upper end portion thereof is covered by the seat back 17 from the side of the occupant room R, it is possible to effectively prevent the head portion H of the occupant from being interfered with the inflator 11. Further, since the pipe member 12 is made of a metal, the temperature of the combustion gas can be correspondingly reduced, so that the influence applied to the air bag main body 10 can be restricted and a heat resisting level of a coating material applied to the inner portion thereof can be reduced. Accordingly, the air bag main body 10 can be made inexpensive. Further, since it is possible to control an injecting characteristic of the combustion gas of the inflator 11, that is, an introducing characteristic of the high pressure gas to the air bag main body 10 by suitably tuning the necking amount d of the pipe member 12, it is not necessary to replace the inflator 11 itself even in the case of employing various kinds of air bag main bodies, so that it is possible to realize an effective structure. In this case, in the present embodiment, the description is given of the embodiment in which the inflator 11 and the pipe member 12 are placed in the rear pillar 3. Further, in the present embodiment, the pipe member 12 is formed in the metal cylindrical shape and the necking amount d is set by contracting the metal cylinder; however, of course, the shape of the pipe member 12 is not limited to the cylindrical shape, for example, a hollow square pillar shape can be employed, and the necking amount d may be set by suitably setting a distance between two opposing surfaces in correspondence to a cross-sectional area, a flow passage length or the like required with respect to the passing high pressure gas. Of course, the material of the pipe member 12 is not limited to metal, and it is a matter of course that a resin material or the like can be employed as far as a necessary mechanical strength, thermal property and the like can be satisfied. Further, in accordance with the present embodiment, the inflator 11 is structured such that the combustion gas is generated with employing a medical agent; however, it is possible to employ a gas combustion type, a high pressure gas sealing type or the like.

Claims: Side air bag apparatus of a vehicle, comprising: an air bag main body (10) arranged along an inner side of an occupant room extending along a side roof rail (4) in a folded state thereof and capable of being deployed downward; an inflator (11) for injecting gas capable of inflating the air bag main body (10) so as to deploy the air bag main body (10) downward, an upper end portion (11a) of the inflator (11) being positioned lower than the normal head position of an occupant; and a gas communication member (12) for.introducing the gas from the inflator (11) to the air bag main body (10), the gas communication member (12) being deformable by an excessive external force; characterized in that the inflator (11) is arranged along a rear pillar (3) in a state of being substantially aligned in a longitudinal direction thereof, the rear pillar (3) extending rearwardly downward from the side roof rail (4), and the upper end portion (11a) of the inflator (11) is set to a position substantially overlapping with a seat back (17) in a side view of the vehicle. Apparatus according to claim 1, wherein the air bag main body (10) develops downward so as to form a curtain shape. Apparatus according to claim 1 or 2, wherein the inflator (11) and the gas communication member (12) are covered by a pillar garnish (15) from the inner side of the occupant room. Apparatus according to any preceding claim, wherein the gas communication member (12) is a metal pipe member. Apparatus according to any preceding claim, wherein the gas communication member (12) connects the inflator (11) and the air bag main body (10) to each other in a curved manner. Apparatus according to any preceding claim, wherein the inflator (11) generates combustion gas, and gas based on the combustion gas is introduced to the air bag main body (10) through the gas communication member (12). Apparatus according to any preceding claim, wherein the gas communication member (12) has a necked portion controlling an injection property of the gas. Apparatus according to claim 7, wherein the necked portion is a contracted portion of the gas communication member (12).

Inventors: MIYAHARA TAKEHIKO, TAJIMA SHUSAKU, MIYAHARA, TAKEHIKO, TAJIMA, SHUSAKU
Applicants: NISSAN MOTOR, NISSAN MOTOR COMPANY, LIMITED
Application year: 2000
Main classification: B60R21
IPC codes: B60R21