Side airbag apparatus

1. A side airbag apparatus of a seat, comprising:

an airbag cushion having:

a rear end configured to be secured to a side surface of the seat;

a front end configured to move forwards while the airbag cushion is deployed forwards when gas is injected into the airbag cushion;

at least one support tether having a first side rotatably coupled to the side surface of the seat about a rotating shaft that extends in a direction parallel to a lateral direction of the seat, the at least one support tether extending in a longitudinal direction; and

at least one outer tether having:

a first end coupled to a second side of the at least one support tether, and

a second end extending in the longitudinal direction and coupled to the front end of the airbag cushion,

wherein the at least one support tether comprises:

a first support tether that extends downwards while a first side of the first support tether is coupled to an upper side of the seat; and

a second support tether that extends upwards while a first side of the second support tether is coupled to a lower side of the seat, and

wherein, when the airbag cushion is deployed, the first support tether and the second support tether are configured to rotate in opposite directions to each other.

2. The side airbag apparatus of claim 1 , further comprising at least one coupling bracket located on a side surface of a seat frame that is disposed in the seat,

wherein the first side of the at least one support tether is rotatably coupled to the coupling bracket,

wherein an outer end of the at least one support tether is configured to extend from the first side of the at least one support tether to an outside, and

wherein the coupling bracket includes a limit slit configured to allow the outer end of the at least one support tether to rotatably move as the at least one support tether rotates about the first side in a predetermine range.

3. The side airbag apparatus of claim 2 , further comprising a support extending in a direction of a plane parallel to the side surface of the seat frame, disposed between the first side of the at least one support tether and the coupling bracket, and configured to be deformed when a pressure exceeding a preset pressure level is applied,

wherein the limit slit is configured to allow the at least one support tether to rotate toward an outside of the seat in a predetermined range.

4. The side airbag apparatus of claim 2 , wherein the limit slit is recessed toward an inside of the seat, and

wherein the first side of the at least one support tether is configured to rotatably move with the outer end of the at least one support tether, the second side of the at least one support tether is configured to be rotatably moved forwards, and the outer end of the at least one support tether is configured to be rotated inwards.

5. The side airbag apparatus of claim 1 , wherein the at least one support tether includes a material having a rigidity higher than that of a material of the outer tether.

6. The side airbag apparatus of claim 1 , wherein the at least one outer tether comprises:

a first outer tether having a first end coupled to the first support tether; and

a second outer tether having a first end coupled to the second support tether, and wherein the first outer tether is coupled to an upper side on the front end of the airbag cushion, and the second outer tether is coupled to a lower side on the front end of the airbag cushion.

7. The side airbag apparatus of claim 1 , wherein the first support tether and the second support tether are spaced apart from each other on the side surface of the seat.

8. The side airbag apparatus of claim 1 , wherein upper and lower portions of the airbag cushion are configured to be folded towards a central portion before the airbag cushion is deployed, and

wherein the folded airbag cushion is disposed on the side surface of the seat and the folded upper and lower portions extend farther outside the seat than the central portion.

9. The side airbag apparatus of claim 8 , wherein, an end of each of the upper and lower portions is disposed on the side surface of the seat while being secondarily folded to the outside of the seat, such that the upper and lower portions folded towards the central portion of the airbag cushion are separated from each other.

10. The side airbag apparatus of claim 8 , wherein a portion of the front end of the airbag cushion is configured to be folded to the outside of the seat to be temporarily attached in a folded state.

11. The side airbag apparatus of claim 8 , wherein the airbag cushion is disposed on the side surface of the seat in a rolled state such that the front end of the airbag cushion in the folded state extends farther out than the rear end.

12. The side airbag apparatus of claim 1 , further comprising an inflator configured to inject gas into the airbag cushion from the rear end of the airbag cushion.

13. The side airbag apparatus of claim 12 , wherein, before the airbag cushion is deployed, the airbag cushion is disposed at an inner position of the seat as compared with the support tether, and is disposed at an outer position of the seat as compared with the inflator.