The present invention relates to an airbag device in which an airbag is inflated to protect an occupant in the event of vehicle collision. More particularly, the present invention relates to an airbag device of which an airbag has an improved configuration accomplishing more effective protection of an occupant.
The following publications are generally related to airbag devices, however, none of the publications has a suggestion or disclosure of the same or similar device and structure proposed by the present invention. The publications are: Japanese Patent Publication No. H08-32511; Japanese Patent Publication No. S49-23176; Japanese Patent Unexamined Publication No. H04-56655; Japanese Patent Unexamined Publication No. H06-191366; Japanese Patent Unexamined Publication No. H06-171447; Japanese Patent Unexamined Publication No. H05-58243; Japanese Patent Unexamined Publication No. 2000-118341; and Japanese Patent Unexamined Publication No. H11-5505.
It is an object of the present invention to provide an airbag device of which an airbag has an improved configuration accomplishing more effective protection of an occupant.
In order to solve the above-described problems, an airbag device according to the first aspect of the present invention is an airbag device comprising an airbag which is normally housed in an upper portion of an instrument panel and is inflated/deployed toward the front of an occupant in the event of emergency, wherein the configuration in a side view of the airbag when fully deployed has the following three characteristics:
(1) the lower end of the airbag is positioned at least lower than the chest of the occupant;
(2) a dent or indentation is formed between an upper portion and a lower portion of the front face of the airbag so as to maintain the airbag in a heart-like configuration when the lower portion is pressed; and
(3) an area including the dent is at least greater than an area coming in contact with the face of the occupant.
According to this configuration, the lower portion of the airbag is pressed by at least a portion under the chest of the occupant so that pressure is supplied from the lower portion to the upper portion of the airbag so as to increase the inner pressure in the upper portion of the airbag. Therefore, the efficiency of absorbing energy is increased and the moving distance of the occupant until stops is reduced, thereby eliminating the requirement of setting the output of the inflator high and achieving more safe restraint of the occupant in the initial stage. The high efficiency of absorbing energy also allows the reduction in the volume of the airbag. Since the frontward movement of the occupant until the occupant makes contact with the airbag is increased by the dent, the occupant comes in contact with the airbag after an amount kinetic energy of the occupant is absorbed by a seat belt.
In the aforementioned airbag device, the dent may be formed in any shape like a recess or a valley in the airbag.
An airbag device according to the second aspect of the present invention comprises an airbag which is normally housed in an upper portion of an instrument panel and is inflated/deployed toward the front of an occupant in the event of emergency, wherein the front face of an upper half of the airbag overhangs toward the occupant to have an angle between 0xc2x0 and 45xc2x0 (preferably, between 15xc2x0 and 25xc2x0) relative to the cervical vertebrae axis of the occupant when the head of the occupant just comes into contact with the airbag in the event of emergency.
Since the front face of the airbag overhangs toward the occupant as mentioned above, a portion corresponding to the mass point (gravitational centers) of the head of the occupant comes into contact with the front face of the airbag, thereby more efficiently restraining the head of the occupant in the initial stage.
An airbag device of the third aspect of the present invention comprises an airbag which is normally housed in an upper portion of an instrument panel and is inflated/deployed toward the front of an occupant in the event of emergency, wherein a dent is formed between an upper portion and a lower portion of the front face of the airbag, and the front face of the airbag overhangs toward the occupant in such a manner that an area of the front face extending from the deepest point of the dent to an upper projection top makes contact with portions corresponding to the mass points (gravitational centers) of the heads of occupants of different builds.
Since the front face of the airbag overhangs toward the occupant as mentioned above, the mass point of the head of the occupant can early restrained. Therefore, the efficiency of absorbing energy is increased, thereby more efficiently restraining the head of the occupant in the initial stage.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only, and are not restrictive of the invention as claimed.