Airbag for front passenger's seat

An airbag for a front passenger's seat mountable on a vehicle, the airbag being folded and housed in a top face of an instrument panel in front of the front passenger's seat, and upon inflow of inflation gas, the airbag protrudes upward and deploys in a rearward direction of the vehicle in such a manner as to occupy a space between the top face of the instrument panel and a wind shield located above the instrument panel, the airbag comprising:

• an inlet port for introducing inflation in the vicinity of a front end of a lower side of the airbag and in the vicinity of a transverse center of the airbag in an inflated state;
• and
• a protection portion contactable with a front seat passenger, in a rear side of the airbag as completely inflated;
• wherein:
• upon airbag inflation, the protection portion comprises:
• left and right shoulder restraining portions disposed generally side by side in left-right orientation, the shoulder restraining portions projecting rearward in such a manner as to contact a passenger's shoulders;
• and
• a recess arranged from upper side to rear side of, and between the shoulder restraining portions;
• the airbag comprises a communication portion proximate to the gas inlet port, wherein the communication portion is defined by the leading end of the recess, and the communication portion permits gas to communicate between the left and right shoulder restraining portions in left-right orientation;
• and
• an opening area of the communication portion, in a section of the completely inflated airbag taken along front-rear orientation at the center of the gas inlet port, is ⅕or greater of a projected area of a side view of the whole airbag as completely inflated;
• the airbag is formed by sewing up edges of a plurality of predetermined base cloths;
• the recess is formed by sewing up edges of base cloths constituting the left and right shoulder restraining portions;
• the airbag, when completely inflated, is formed into a generally square conical shape in which a top of the square conical shape is in a front end of the airbag, and a rear side constituting the protection portion is in a bottom side of the airbag;
• the airbag upon inflation comprises:
• an outer panel constituting areas of left and right side walls of the square conical shape, and an inner panel constituting areas from an upper side wall to a lower side wall via a rear side wall of the square conical shape, between the left and right side walls;
• the inner panel consists of a pair of inner panel base cloths having the same shapes, the inner panel base cloths has such a construction, upon airbag inflation, as to divide the inner panel into two in left-right orientation;
• each of the inner panel base cloths has a band shape curved in a generally C-shape, and an outer edge of each of the inner panel base cloths has generally the same shape as an outer edge of a portion of the outer panel constituting the left/right side wall;
• the inner panel is formed by joining the outer edges of the inner panel base cloths to the outer edges of the portions of the outer panel constituting the areas of the left and right side walls, and by joining inner edges of the inner panel base cloths to each other;
• and
• the recess is defined by a joint of the inner edges of the inner panel base cloths.