Knee airbag apparatus
A knee airbag apparatus including an airbag cushion including a lower sheet portion, an upper sheet portion to overlap the lower sheet portion to form a cushion space together with the lower sheet portion, and a folded portion formed by folding the upper sheet portion so that portions of the upper sheet portion overlap partially, and an inflator to supply a gas to the cushion space so that the airbag cushion is deployed.
1 . A knee airbag apparatus comprising:
an airbag cushion comprising a lower sheet portion, an upper sheet portion configured to overlap the lower sheet portion to form a cushion space together with the lower sheet portion, and a folded portion formed by folding the upper sheet portion so that portions of the upper sheet portion overlap partially;
an inflator configured to supply a gas to the cushion space so that the airbag cushion is deployed; and
a mouth tether positioned in the cushion space closer to a first end than a second end of the airbag cushion and comprising a first end coupled to the folded portion, and a second end coupled to the lower sheet portion,
wherein the mouth tether comprises:
a first mouth tether; and
a second mouth tether comprising a first end coupled to the folded portion together with a first end of the first mouth tether, and a second end coupled to the lower sheet portion at a position different from a position at which a second end of the first mouth tether is coupled to the lower sheet portion,
wherein the folded portion comprises a pair of folded piece portions defining a gap therebetween,
wherein the first end of the first mouth tether and the first end of the second mouth tether are fitted into the gap and sewn to the folded portion by a sewed portion,
wherein the second end of the first mouth tether is positioned closer to the first end of the airbag cushion than the second end of the second mouth tether, and
wherein a length from the first end to the second end of the second mouth tether is shorter than a length from the first end to the second end of the first mouth tether.
2 . The knee airbag apparatus of claim 1 , wherein the second end of the airbag cushion is opposite to the first end of the airbag cushion in a longitudinal direction, the inflator is positioned in the cushion space closer to the first end than the second end of the airbag cushion, and the folded portion is positioned closer to the first end than the second end of the airbag cushion.
3 . The knee airbag apparatus of claim 2 , further comprising:
a heat-resistant layer stacked on an inner surface of the first end of the airbag cushion.
4 . The knee airbag apparatus of claim 2 , wherein an end of the lower sheet portion that is coupled to an end of the upper sheet portion by a sewed portion is an end of the lower sheet that is farthest from the second end of the airbag cushion.
5 . The knee airbag apparatus of claim 1 , wherein a thickness of the first mouth tether is larger than a thickness of the second mouth tether.
6 . The knee airbag apparatus of claim 1 , further comprising:
a center tether positioned between the second end of the airbag cushion and the mouth tether in the cushion space and having a first end coupled to the upper sheet portion, and a second end coupled to the lower sheet portion.
7 . The knee airbag apparatus of claim 1 , further comprising:
an airbag housing defining an internal space in which the airbag cushion is accommodated in a folded state; and
a hook tether comprising a first end coupled to the folded portion, and a second end configured to penetrate the airbag housing and connected to the airbag housing.
8 . The knee airbag apparatus of claim 7 , wherein the airbag housing comprises:
a base connected to the hook tether; and
a cover coupled to the base and configured to separate from the base when the airbag cushion is deployed.
9 . The knee airbag apparatus of claim 1 , further comprising:
a cushion cover configured to block the deployment of the airbag cushion so that the airbag cushion is kept folded when gas is not supplied to the cushion space by the inflator.
10 . The knee airbag apparatus of claim 9 , further comprising:
an airbag housing defining an internal space in which the airbag cushion is accommodated in a folded state,
wherein the cushion cover comprises a first end coupled to an outer surface of the airbag cushion, and a second end coupled to the airbag housing, and
wherein the cushion cover is disconnected or the second end of the cushion cover is separated from the airbag housing when the airbag cushion is deployed.
11 . The knee airbag apparatus of claim 1 , further comprising:
a cushion flap comprising a first end coupled to the folded portion, and a second end that is a free end.
12 . The knee airbag apparatus of claim 1 , further comprising:
a diffuser configured to surround the inflator and diffuse a gas discharged from a gas discharge port of the inflator.