Airbag apparatus

Abstract

The airbag apparatus includes an airbag having a tether including an occupant side tether belt and a vehicle body side tether belt. An intermediate portion of the vehicle body side tether belt is held at the side of a housing of the airbag by a retaining mechanism. At full inflation of the airbag, the clearance between the side of the housing and the occupant side tether belt is reduced when the vehicle body side belt is retained by the retaining mechanism whereas the clearance is enlarged when the vehicle body side tether belt is released from the retaining mechanism. The occupant side tether belt and the vehicle body side tether belt are linked with each other so that a central area of a protection plane of an occupant side wall of the airbag in the former case is generally parallel to the central area in the latter.

Description

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates a steering wheel including an airbag apparatus embodying the present invention and an occupant (driver) as viewed from the side;

FIG. 2 is a partial plan view of the steering wheel of FIG. 1 showing the way the airbag apparatus is mounted thereon;

FIG. 3 is a schematic section of the airbag apparatus of the present invention, taken along line III-III of FIG. 2;

FIG. 4 is a partial schematic section of the airbag apparatus of FIG. 3, taken along line IV-IV of FIG. 3;

FIG. 5 is a plan view of an airbag used for the airbag apparatus of FIG. 3 in a flattened state;

FIG. 6 is a bottom view of the airbag of FIG. 5 in the flattened state;

FIG. 7 is a schematic section of the airbag of FIG. 5 taken long the lateral direction for showing a loop projected from an aperture;

FIG. 8 is an exploded perspective view showing components of the airbag of FIG. 5;

FIGS. 9A and 9B are schematic sections of the airbag of FIG. 5 inflated by itself taken along the lateral direction, showing the cases where the loop is retained by a retaining mechanism and is released from the retaining mechanism;

FIG. 10 is a schematic section of the airbag of FIG. 5 inflated by itself taken along the longitudinal direction when the loop is released from the retaining mechanism;

FIG. 11 is a schematic vertical section of the airbag apparatus of FIG. 3 in service;

FIGS. 12A and 12B are schematic sections of a modification of the airbag of the present invention inflated by itself, showing the cases where an intermediate portion of a vehicle body side tether belt is retained by a retaining mechanism and is released from the retaining mechanism;

FIGS. 13A and 13B are schematic sections of a further modification of the airbag inflated by itself, showing the cases where an intermediate portion of the vehicle body side tether belt is pulled and is not pulled; and

FIG. 14 is a schematic exploded perspective view of a modification of an occupant side tether belt.

Claims

1. An airbag apparatus comprising: a bag-shaped airbag folded and housed in a housing and inflatable with inflation gas, the airbag including an occupant side wall arranged toward a seat upon airbag inflation and a vehicle body side wall arranged toward the housing upon airbag inflation and attached to the housing;a tether joined to a side of the housing and the occupant side wall inside the airbag for regulating a clearance between the occupant side wall and the housing upon airbag inflation;a control device deciding upon a preferred mode of the airbag of receiving an occupant; anda retaining mechanism controlled by the control device,wherein:the tether includes an elongate first tether element joined to the occupant side wall and an elongate second tether element linked with the first tether element and joined to the side of the housing;the retaining mechanism holds an intermediate portion of the second tether element disposed between the side of the housing and a link portion with the first tether element at the side of the housing to reduce a clearance in the second tether element between the housing and the first tether element, and the retaining mechanism releases the intermediate portion of the second tether element to enlarge the clearance in the second tether element between the housing and the first tether element, whereby varying a clearance between the occupant side wall and the housing at full inflation of the airbag;the first tether element is linked with the second tether element in such a manner that a link portion of the first tether element with the second tether element is slidable on the second tether element, such that a central area of a protection plane of the occupant side wall for arresting the occupant at the time the clearance between the occupant side wall and the housing is reduced and the central area of the protection plane at the time the clearance between the occupant side wall and the housing is enlarged are generally parallel at full inflation of the airbag.

2. The airbag apparatus of claim 1, wherein: the first tether element extends in a bifurcate or radial fashion from the link portion with the second tether element, and is joined to the occupant side wall at ends of portions thereof extending in the bifurcate or radial fashion; andan area of the occupant side wall encircled by joint regions of the first tether element and the occupant side wall constitutes the central area of the protection plane.

3. The airbag apparatus of claim 1, wherein: the second tether element is joined to the side of the housing at opposite ends thereof; andthe second tether element is linked with the first tether element at an intermediate region thereof.

4. The airbag apparatus of claim 2, wherein: the second tether element is joined to the side of the housing at opposite ends thereof; andthe second tether element is linked with the first tether element at an intermediate region thereof.

5. The airbag apparatus of claim 4, wherein: the first tether element has a band shape, and is joined to the occupant side wall at opposite ends of the length direction thereof;the second tether element has a band shape, and is joined to the side of the housing at opposite ends of the length direction thereof; andthe first tether element and the second tether element are linked with each other in a crossing manner at respective intermediate regions of the first and second tether elements so that the first tether element and second tether element are overlaid one on the other at the intermediate regions and retain each other.

6. The airbag apparatus of claim 5, wherein the first tether element and the second tether element are arranged generally orthogonal to each other in a plan view.

7. The airbag apparatus of claim 5, wherein: the airbag apparatus further includes an inflator inserted into the airbag for supplying the airbag with inflation gas;the second tether element has a width wide enough to cover sides of the inflator; andthe second tether element is joined to the vicinity of the sides of the inflator at the opposite ends thereof such that the second tether element redirects the inflation gas toward the width direction of the second tether element inside the airbag.

8. The airbag apparatus of claim 7, wherein the second tether element is arranged generally along the lateral direction of vehicle.