Reivindicaciones

1. Airbag having an inflatable bag (12) comprising a gas venting zone constituted by an aperture (30, 40, 50) made in the bag (12) and a sealing patch (22) designed to rupture under the effect of the internal pressure in the bag, characterized in that the aperture has a shape such that its surface area SO is less than the venting surface area SV produced after the rupture of the patch and which, for patches made from the same material, makes it possible to modify their bursting pressure by varying one of the internal dimensions of the aperture. 2. Airbag according to Claim 1, characterized in that the shape of the aperture makes it possible, for a predetermined bursting pressure, to increase the venting surface area by enlarging the external dimensions of the aperture and keeping at least one of the internal dimensions constant. 3. Airbag according to Claim 1 or 2, characterized in that the abovementioned aperture is of H-shaped configuration. 4. Airbag according to Claim 1 or 2, characterized in that the abovementioned aperture is of cruciform configuration. 5. Airbag according to Claim 1 or 2, characterized in that the abovementioned aperture is of C-shaped configuration. 6. Airbag according to any one of the preceding claims, characterized in that the sealing patch is made from silicone and has a constant thickness.