Pneumatic tire
View Patent ↗A pneumatic tire in which an inner liner including a film mainly made of thermoplastic resin is attached to an inside of the tire via a tie rubber sheet, on an inner side of a carcass layer, and which has a lap-splice portion where end portions of the film in a tire circumferential direction overlap each other in a tire widthwise direction with tie rubber therebetween. A section of the film on a tire cavity side in the lap-splice portion has a portion where the film is thin over part or entirety of the width in the tire widthwise direction before the lap-splice portion, or a film thickness in the lap-splice portion is smaller than a film thickness in a portion other than the lap-splice portion. Thus, the pneumatic tire has no crack developing around the lap-splice portion of an inner liner layer after running, and has excellent durability.
1. A pneumatic tire comprising:
a carcass layer; and
an inner liner including a film mainly including a thermoplastic resin that is attached to an inside of the tire via a tie rubber sheet on an inner side of the carcass layer, the inner liner having a lap-splice portion where end portions of the film in a tire circumferential direction overlap each other in a tire widthwise direction with tie rubber therebetween, at least one of a section of the film on a tire cavity side and a section of the film on a tire outer circumference side in the lap-splice portion being formed in such a way that a film thickness in the lap-splice portion is smaller than a film thickness in a portion other than the lap-splice portion, a portion of the lap-splice portion which extends from a free distal end of the lap-splice portion and is formed to be thinner than a film thickness of the portion other than the lap-splice portion being formed to have such a shape that the film becomes thinner stepwise, and a film thickness of an entirety of the portion of the lap-splice portion where the film is thin being 20% to 80% of the thickness of the film in the portion other than the lap-splice portion.
2. The pneumatic tire according to claim 1 , wherein
an overlap length of the lap-splice portion in the circumferential direction is 3 to 30 mm.
3. The pneumatic tire according to claim 1 , wherein
the portion of the lap-splice portion which is formed to be thinner than a film thickness of the portion other than the lap-splice portion exists at least in a region between a belt end portion and a tip of a bead filler portion in a cross section along a tire meridian line.
4. The pneumatic tire according to claim 1 , wherein
the section of the film on the tire cavity side is formed in such a way that a film thickness in the lap-splice portion is smaller than a film thickness in a portion other than the lap-splice portion.
5. The pneumatic tire according to claim 1 , wherein
the section of the film on a tire outer circumference side in the lap-splice portion is formed in such a way that a film thickness in the lap-splice portion is smaller than a film thickness in a portion other than the lap-splice portion.
6. The pneumatic tire according to claim 1 , wherein
the section of the film on a tire cavity side and the section of the film on a tire outer circumference side in the lap-splice portion are formed in such a way that a film thickness in the lap-splice portion is smaller than a film thickness in a portion other than the lap-splice portion.