Air bag mounting in a vehicle

Abstract: An instrument panel (1) presents an opening for accommodating an air bag, and a structure element (4) is provided behind this opening. A mounting part (9) at the bottom of an air bag unit (6) is fixed to a bracket (5) of the structure element (4) with bolts (10). The air bag unit (6) has other mounting parts (8) at its opposite sides, at which the air bag unit (6) is fixed with bolts (18) to brackets (13) mounted at opposite sides of the opening (2). The brackets (13) are made of steel plates, and have upper and lower ends connected to the instrument panel with screws (14) via reinforcing bosses (15) or reinforcing elements (12).

Description: BACKGROUND OF THE INVENTION Field of the Invention This invention relates to an air bag equipment attached to the instrument panel in front of the front passenger seat of a vehicle. Related Art Fig. 3 is a perspective view of a mounting structure of a conventional air bag equipment, and Fig. 4 is a cross-sectional view taken along the B-B line of Fig. 3. An instrument panel 1 of a vehicle has formed an opening 2 for accommodating an air bag, and a structure element 4 is provided in the inside of the opening 2. An air bag unit 6 includes a casing containing an air bag, inflator and related elements and closed by a door 7. The air bag unit 6 has fixture means 8 at opposite sides of the casing, and another fixture means 9 at its lower portion for connection to the structure element 4. The instrument panel 1 also has formed a resin-made fixture means 3 which is integrally molded on opposite inner sides of the opening 2. The fixture means 8 of the air bag unit 6 is connected to the resin-made fixture means 3 with bolts 18 and nuts 17. The lower fixture means 9 of the air bag unit is fixed to a bracket 5 associated with the structure element 4 with bolts 10. This type of mounting structure of a front passenger seat air bag equipment is disclosed in Japanese Utility Model Laid-Open No. 1-81156 (1989). An air bag mounting according to the preamble of claim 1 is known from US-A-5 413 379. When the air bag expands, a reactive force causes the air bag unit to rotate about the lower fixture means. As a result, a stress concentrated to the junction between the air bag unit and the instrument panel may cause a crack in the instrument panel. If the instrument panel-breaks upon expansion of the air bag due to a small collision, the repair cost of the vehicle with the air bag is heavier for the user than a vehicle with no air bag. SUMMARY OF THE INVENTION In order to solve the problems involved in the conventional systems, the invention as defined in claim 1, prevents a crack of the instrument panel only by a reaction force upon expansion of the air bag while satisfying both good fitting between the door of the air bag unit and the opening of the instrument panel and easy mounting of the air bag unit to the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view of a mounting structure of an air bag mounting according to the invention; Fig. 2 is a cross-sectional view taken along the A-A line of Fig. 1; Fig. 3 is a perspective view of a mounting structure of a conventional air bag mounting; and Fig. 4 is a cross-sectional view taken along the B-B line of Fig. 3. DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the invention is described below with reference to Fig. 1 and Fig. 2. An instrument panel 1 of a vehicle has formed an opening 2 for accommodating an air bag, and a structure element 4 is provided in the inside of the opening 2. An air bag unit 6 includes a casing containing the air bag, inflator and other related elements, and closed by a door 7. The air bag unit 6 also has formed fixture portions 8 at opposite sides of the casing, and another fixture portion 9 at its lower portion for connection to the structure element. The steel brackets 13 are located at opposite sides of the air bag opening 2 of the instrument panel 1. Each bracket 13 includes a burring bore 16 at its lower end in which a screw 14 is received via a reinforcing element 12 to join the bracket 13 to the instrument panel 1. The upper end of the bracket 13 is connected to a resin boss 15 extending from the instrument panel 1 by means of a screw 14 The bracket 13 is a flat shaped steel plate easily deformable when a force is applied. Fixed to middle portions of the brackets 13 are fixture portions 8 of the air bag unit 6 by using stud bolts 17 and nuts 18. The structure element 4 commonly used as a steering support member has an air bag fixture bracket 5 which rigidly fixes the lower fixture portion 9 of the air bag unit with a fixture bolt 10 In the mounting described above, when the air bag develops, a reactive force causes a rotating movement of the air bag unit about the lower fixture portion and the steel brackets 13 deform so as to absorb the reaction force As a result, cracks or other breakage does not occur in the resin-made instrument panel 1 According to the construction of the invention, a crack of the instrument panel only by a reaction force upon expansion of the air bag can be prevented while both good fitting between the door of the air bag unit and the opening of the instrument panel and easy mounting of the air bag unit in a vehicle are satisfied. The above advantage minimizes the cost for repairing the air bag unit and/or related parts after small collision of the vehicle. Also prevented is a decrease in performance of the air bag due to a breakage of the air bag caused by cracks in the instrument panel Since cracks in the instrument panel can be prevented, passengers in the vehicle will not be injured by scattered pieces of resin. Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the scope of each element identified by way of example by such reference signs.

Claims: An air bag mounting equipped at a position of an instrument panel (1) of a vehicle in front of a front passenger seat, comprising: an air bag unit (6) including a casing; a bottom fixture means (9) provided at a bottom portion of the casing; and side fixture means (8) provided at opposite sides of the casing, the bottom fixture means (9) being fixed to a structure element (4) of the vehicle and the side fixture means (8) being fixed to brackets (13), each bracket (13) being in form of a flat shaped plate mounted at first and second locations at inner opposite sides of an opening (2) in the instrument panel (1), each bracket (13) having a length between the first and second location greater than the distance from the first location to the second location, characterized in that each bracket (13) is in form of a flat shaped steel plate having two ends which are bent in opposite directions, whereby each bracket (13) includes a first deformable portion between the side fixture means (8) and the first location; and a second deformable portion between the side fixture means (8) and the second location, such that the brackets (13) deform easily so as to absorb the reaction force upon expansion of an air bag. The air bag mounting according to claim 1, characterized in that each bracket (13) has a burring hole (16) at its end portion for fixing the air bag mounting to the instrument panel (1) by a screw (14). The air bag mounting according to claims 1 or 2, characterized in that the first and second deformable portions of each bracket (13) are bent at opposite directions by a respective angle of about ninety degrees.

Inventors: MATSUMOTO TADAHIRO, MATSUMOTO, TADAHIRO
Applicants: ISUZU MOTORS LTD, ISUZU MOTORS LIMITED
Application year: 1996
Main classification: B60R21
IPC codes: B60R21, B60K37