Curtain airbag device

1. A curtain airbag configured to be deployed downwardly along an inner side surface of a vehicle cabin, the curtain airbag comprising:

a non-inflatable portion; and

inflatable cells disposed along a front side and a rear side of the non-inflatable portion,

wherein a first lower-side inflatable cell and a second lower-side inflatable cell are disposed below the non-inflatable portion, and wherein the first and second lower-side inflatable cells each have a middle portion in a longitudinal direction of the lower-side inflatable cells that are formed in a convex shape projecting downwardly;

wherein the first lower-side inflatable cell and the second lower-side inflatable cell are separated by a concave portion of the airbag that projects upwardly;

wherein the convex shape of the first lower-side inflatable cell is directly below and directly abutting the non-inflatable portion;

wherein a center line of the first lower-side inflatable cell has a lowermost point at a middle portion; and

wherein the center line gradually rises from the middle portion toward the front side and the rear side.

2. A curtain airbag as claimed in claim 1 , wherein, when the curtain airbag is not inflated, the lowermost point is positioned from 10 to 150 mm lower than a segment of a line that connects points on the center line of the first lower-inflatable cell that are 250 mm before and 250 mm behind the lowermost point.

3. A curtain airbag as claimed in claim 1 , wherein the first lower-side inflatable cell, the second lower-side inflatable cell, and the concave portion are directly connected to one another.

4. A curtain airbag as claimed in claim 1 , wherein the center line gradually rises upward from the middle portion to front and rear sides of the convex shape.

5. A curtain airbag device comprising:

a curtain airbag configured to be deployed downwardly along an inner side surface of a vehicle cabin; and

a gas generator for supplying gas into the curtain airbag to inflate the curtain airbag,

wherein a portion of the curtain airbag is non-inflatable,

wherein inflatable cells are disposed along a front side and a rear side of the non-inflatable portion,

wherein a lower-side inflatable cell is disposed below the non-inflatable portion,

wherein the lower-side inflatable cell has a portion in a longitudinal direction of the lower-side inflatable cell that is formed in a convex shape projecting downwardly;

wherein the portion of the lower-side inflatable cell formed in a convex shape extends in a longitudinal direction of the curtain airbag for a distance that is less than a full length of the curtain airbag;

wherein the convex shape of the lower-side inflatable cell is directly below and directly abutting the non-inflatable portion;

wherein a center line of the lower-side inflatable cell has its lowermost point at a middle portion; and

wherein the center line gradually rises from the middle portion toward the front side and the rear side.

6. A curtain airbag device as claimed in claim 5 , wherein, when the curtain airbag is not inflated, the lowermost point is positioned from 10 to 150 mm lower than a segment of a line that connects points on the center line of the lower-inflatable cell that are 250 mm before and 250 mm behind the lowermost point.

7. A curtain airbag device as claimed in claim 5 , wherein the lower-side inflatable cell is a first lower-side inflatable cell;

further comprising a second lower-side inflatable cell with a portion in a longitudinal direction of the second lower-side inflatable cell that is formed in a convex shape projecting downwardly;

wherein the second lower-side inflatable cell is located forward of the first lower-side inflatable cell along a longitudinal direction of the curtain airbag.

8. A curtain airbag device as claimed in claim 7 , further comprising a concave portion of the airbag that projects upwardly, wherein the concave portion separates the first lower-side inflatable cell and the second lower-side inflatable cell;

wherein the first lower-side inflatable cell, the second lower-side inflatable cell, and the concave portion are directly connected to one another.

9. A curtain airbag device as claimed in claim 5 , wherein the center line gradually rises upward from the middle portion to front and rear sides of the convex shape.

10. A curtain airbag device comprising:

a curtain airbag configured to be deployed downwardly along an inner side surface of a vehicle cabin; and

a gas generator for supplying gas into the curtain airbag to inflate the curtain airbag,

wherein a portion of the curtain airbag is non-inflatable,

wherein inflatable cells are disposed along a front side and a rear side of the non-inflatable portion,

wherein a first lower-side inflatable cell and a second lower-side inflatable cell are disposed below the non-inflatable portion,

wherein the first and second lower-side inflatable cells each have a portion in a longitudinal direction of the lower-side inflatable cells that is formed in a convex shape projecting downwardly;

wherein the first lower-side inflatable cell and the second lower-side inflatable cell are separated by a concave portion of the airbag that projects upwardly;

wherein the convex shape of the first lower-side inflatable cell is directly below and directly abutting the non-inflatable portion;

wherein a center line of the first lower-side inflatable cell has a lowermost point at a middle portion; and

wherein the center line gradually rises from the middle portion toward the front side and the rear side.

11. A curtain airbag device as claimed in claim 10 , wherein, when the curtain airbag is not inflated, the lowermost point is positioned from 10 to 150 mm lower than a segment of a line that connects points on the center line of the first lower-inflatable cell that are 250 mm before and 250 mm behind the lowermost point.

12. A curtain airbag device as claimed in claim 10 , wherein the first lower-side inflatable cell, the second lower-side inflatable cell, and the concave portion are directly connected to one another.

13. A curtain airbag device as claimed in claim 10 , wherein the center line gradually rises upward from the middle portion to front and rear sides of the convex shape.

14. A curtain airbag configured to be deployed downwardly along an inner side surface of a vehicle cabin, the curtain airbag comprising:

a non-inflatable portion; and

inflatable cells disposed along a front side and a rear side of the non-inflatable portion,

wherein a lower-side inflatable cell is disposed below the non-inflatable portion, and wherein the lower-side inflatable cell has a middle portion in a longitudinal direction of the lower-side inflatable cell that is formed in a convex shape projecting downwardly;

wherein the portion of the lower-side inflatable cell formed in a convex shape extends in a longitudinal direction of the curtain airbag for a distance that is less than a full length of the curtain airbag;

wherein the convex shape of the lower-side inflatable cell is directly below and directly abutting the non-inflatable portion;

wherein a center line of the lower-side inflatable cell has its lowermost point at a middle portion, and

wherein the center line gradually rises from the middle portion toward the front side and the rear side.

15. A curtain airbag as claimed in claim 14 , wherein, when the curtain airbag is not inflated, the lowermost point is positioned from 10 to 150 mm lower than a segment of a line that connects points on the center line of the lower-inflatable cell that are 250 mm before and 250 mm behind the lowermost point.

16. A curtain airbag as claimed in claim 14 , wherein the lower-side inflatable cell is a first lower-side inflatable cell;

further comprising a second lower-side inflatable cell with a middle portion in a longitudinal direction of the second lower-side inflatable cell that is formed in a convex shape projecting downwardly;

wherein the second lower-side inflatable cell is located forward of the first lower-side inflatable cell along a longitudinal direction of the curtain airbag.

17. A curtain airbag as claimed in claim 16 , further comprising a concave portion of the airbag that projects upwardly, wherein the concave portion separates the first lower-side inflatable cell and the second lower-side inflatable cell;

wherein the first lower-side inflatable cell, the second lower-side inflatable cell, and the concave portion are directly connected to one another.

18. A curtain airbag as claimed in claim 14 , wherein the center line gradually rises upward from the middle portion to front and rear sides of the convex shape.