Automotive air bag device

[0002] The present invention relates to an automotive air bag device and, more particularly, to an automotive air bag device wherein the air bag inflation opening is formed in an automotive panel such as an instrument panel or a door panel, and this opening is covered with an air bag lid.

[0003] Referring to FIG. 4, there is shown a conventional passenger-side automotive air bag device 2 disposed in an automobile instrument panel 1. In the illustration, air bag 2 device is installed at an angle that allows it to be easily viewed in the drawing. This does not necessarily correspond to actual installation angles.

[0004] Instrument panel 1 is formed of a two-layer material including a core material 1aand a surface material 1b.A rectangular air bag inflation opening 1cis formed at a prescribed position on instrument panel 1.

[0005] Air bag device 2 includes a semi-cylindrical metal case 4 fixed to a vehicle body via a bracket 3. An inflator 5, housed in case 4, inflates an air bag 6 when inflator 5 is activated. A metal guide member 8 is fixed to case 4 by a plurality of mechanical fasteners 7,7 (only two are shown). An air bag lid 10 is fixed to guide member 8 by a plurality of mechanical fasteners 9,9 (only two are shown). These elements are assembled to the vehicle body as a single unit.

[0006] Air bag lid 10 covers opening 1cof instrument panel 1. Air bag lid 10 includes a main lid unit 10bhaving a scoreline 10a.Legs 10c,projecting from the back surface of main lid unit 10b,are fastened to guide member 8 so as to retain lid 10 when air bag 6 inflates.

[0007] In air bag device 2, bracket 3, case 4, inflator 5, air bag 6, guide member 8, and air bag lid 10 comprise a subassembly. When installing this subassembly in the vehicle body, the proper alignment of air bag lid 10 with opening 1cis difficult to achieve. Proper alignment requires the edges of opening 1cand the outer edges of air bag lid 10 be aligned both along the plane of the opening and along the depth axis, i.e. alignment must be performed in three dimensions. If perfect alignment is not achieved, the cosmetic appearance of instrument panel 1 will suffer.

[0008] Furthermore, the inclusion of guide member 8, which maintains subassembly integrity when air bag 10 inflates, increases the size of air bag device 2, thus making the alignment operation described above even more difficult. Finally, the subassembly includes a substantial number of parts, so that material and assembly costs are high.

[0009] It is a primary object of the present invention to overcome the problems described above by providing an automotive air bag device wherein the air bag lid can be easily aligned with the automotive panel.

[0010] It is a further object to provide an automotive air bag device which offers reduced material and assembly costs while maintaining its structural integrity when the inflator is activated.

[0011] Briefly stated, the present invention provides an automotive air bag device which offers ready installation in an automobile instrument panel while reducing material and assembly costs and maintaining its structural integrity when activated. An air bag inflation opening, formed in the instrument panel, is surrounded by an internal reinforcement wall. An air bag lid, which covers the opening, includes an inwardly directed leg which engages the reinforcement wall. A case, which supports an inflator and a diffuser, is fastened to the leg on the lid.

[0012] According to an embodiment of the invention, there is provided an automotive air bag device comprising: an automotive panel having an inner surface and defining an air bag inflation opening, a reinforcement wall on the inner surface of the instrument panel, surrounding the air bag inflation opening, an air bag lid, a leg projecting from the air bag lid and engageable with the reinforcement wall to retain the air bag lid in covering relation to the air bag inflation opening, a case attached to the leg, and an inflator disposed within the case.

[0013] According to a feature of the invention, there is provided an automotive air bag installation comprising: an instrument panel, an air bag opening in the instrument panel, an air bag lid, the air bag lid fitting the air bag opening and forming a contiguous portion of the instrument panel, at least one projection on one of the air bag lid and the instrument panel, an engagement portion on the other of the air bag lid and the instrument panel, the projection and the engagement portion interengaging when the air bag lid is inserted into the air bag opening, and a resulting interengagement being effective for retaining the air bag lid in position in the air bag opening whereby the air bag lid is installed by the insertion.

[0014] These objects are achieved by an air bag device wherein an air bag inflation opening is formed in the automobile panel, with a reinforcement wall surrounding the back side of the opening. An air bag lid, which covers the opening, includes an inwardly directed leg which is fastened to the reinforcement wall. A case, which supports an inflator and a diffuser, is also fastened to the leg on the lid.

[0015] The above, and other objects and advantages of the present invention will become apparent from the following description read in conjunction with the accompanying drawings, in which like numerals designate the same elements.

[0016] FIG. 1 is a cross-section view of an automotive air bag device according to the present invention.

[0017] FIG. 2 is a cross-section view illustrating fabrication of the core material of the instrument panel.

[0018] FIG. 3 is a perspective view of an instrument panel in which the air bag has been installed.

[0019] FIG. 4 is a cross-section view of a conventional automotive air bag device.

[0020] Referring now to FIG. 1, there is shown an automobile instrument panel 11 fabricated from a core material 12 partially covered by a surface material (elastic pad member) 13. On the upper surface of instrument panel 11, toward the passenger seat side, there is disposed an air bag device 14.

[0021] A substantially rectangular opening 12ais formed in core material 12. A reinforcement wall 12csurrounds a back surface 12bof opening 12a.

[0022] Walls 12e,12f,forming a part of reinforcing wall 12c,are sloped from surface 12dtoward the center of opening 12a.On walls 12e,12f,a plurality of comb-like ribs 12g,12hare formed generally perpendicular to surface 12dand have distal edge surfaces substantially parallel to legs 15dof air bag lid 15.

[0023] A reinforcement wall 12iis formed behind wall 12eand parallel thereto. A plurality of ribs 12jis formed between reinforcement wall 12iand wall 12e.The end surfaces of ribs 12jare formed along surface 12dof core material 12.

[0024] Referring to FIG. 2, there is shown a parting line PL between upper and lower dies 31, 32 used to mold core material 12. Parting line PL is set to lie on a line connecting the area around the upper end of rib 12gand the area around the bottom end of wall 12f.Wall 12eis positioned so that it is sloped lower than the bottom end of wall 12f.Thus, when core material 12 is to be removed from the mold, upper and lower dies are pulled away in the same direction as the incline angle (see arrows P, Q in FIG. 2). This prevents undercutting, thus allowing the dies to be made inexpensively and easily without requiring a slide or the like to be disposed on the die.

[0025] A plurality of ribs 12kis formed behind wall 12fin a manner similar to ribs 12h.A lance 12mprojects from the surface of wall 12f.Ribs 12g,12hand the portion positioned on a line extending downward from this end surface together form inner wall 12n.

[0026] In addition to instrument panel 11 described above, air bag device 14 further includes an air bag lid 15 formed from a thermoplastic elastomer or the like and supported by core material 12 so as to cover opening 12a.A case 20 is fastened by brackets 17, 18 and a bolt 19 to a steering support member 16, which is in turn fixed to the vehicle body. A diffuser 22, supported by case 20, houses an inflator 21. A folded air bag 23, stored in a space defined by case 20 and leg 15d,is connected to the gas discharge opening 22aof diffuser 22. Referring to FIG. 1, there is also shown a front window glass 24.

[0027] Air bag lid 15 includes a cover 15acontiguous and blending smoothly with the surface of instrument panel 11. A generally H-shaped score line is formed on the back surface 15bof cover 15a(see FIG. 1, FIG. 3). A leg 15dprojects from back surface 15bof cover 15aso that it faces inner wall 12nof reinforcement wall 12c.Engagement openings 15e,15e(only two are shown) are formed at a plurality of prescribed positions toward the bottom end of leg 15d.Engagement piece 15fand engagement portion 15gproject from back surface 15bof cover 15a,extending out from leg 15dwhich is positioned between rib 12gand rib 12h.Cover 15ais positioned flush with surface material 13, thus providing improved cosmetic appearance.

[0028] A lance 15h,formed on engagement piece 15f,engages the upper end of reinforcement wall 12c.A second lance 15i,formed on engagement portion 15g,engages lance 12m.This allows air bag lid 15 to be supported by reinforcement wall 12cso that opening 15ais covered. It will be appreciated that lance 15hcan engage reinforcement wall 12cwithout requiring a special engagement opening. Thus, the loss of strength accompanying the presence of an engagement hole is avoided.

[0029] Hooks 20a,20a,which engage engagement opening 15e,are formed integrally with or are fixed to the end of case 20 to provide a connection with air bag lid 15.

[0030] To assemble air bag device 14 described above, opening 12aand reinforcement wall 12care formed in core material 12. Next, lance 15iof engagement portion 15gis engaged with lance 12m,and lance 15his engaged with the upper end of reinforcement wall 12c.Thus, air bag lid 15 is supported by reinforcement wall 12cso as to cover opening 12a.Air bag lid 15 is directly supported by core material 12. This makes it possible to easily perform three-dimensional alignment of air bag lid 15 relative to opening 12a.

[0031] Air bag 23 and diffuser 22 are fixed to cover 20, with a portion of air bag 23 covering diffuser 22. Hooks 20a,20aare then engaged with engagement openings 15e,15eand cover 20 is mounted on steering support member 16.

[0032] The size of engagement opening 15eis such that the relative positioning between cover 20 and steering support member 16 remains fixed, and also so that relative positioning between air bag lid 15 and opening 12adoes not change due to looseness and the like during the assembly process.

[0033] When inflator 21 is activated, air bag 23 inflates and presses against leg 15dand inner wall 12n,as well as cover 15aof air bag lid 15. Cover 15abreaks open at score line 15cso that air bag 23 may inflate outwardly. Thus, subassembly integrity is maintained without the use of guide member 8 shown in the conventional technology.

[0034] When air bag 23 inflates, upward pressure is generated on cover 15a,but this pressure is absorbed by lance 15hand hook 20aof cover 20, thus preventing air bag lid 15 from separating from instrument panel 11.

[0035] Having described the presently preferred embodiment of the invention with reference to the accompanying drawings, it is to be understood that the invention is not limited to the precise embodiment described, and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the invention as defined in the appended claims.