PNEUMATIC TIRE
Provided is a pneumatic tire that can provide improved transponder durability while ensuring tire durability. The pneumatic tire includes: a tread portion ( 1 ) extending in a tire circumferential direction and having an annular shape; a pair of sidewall portions ( 2 ) disposed on both sides of the tread portion ( 1 ); and a pair of bead portions ( 3 ) disposed on an inner side in a tire radial direction of the sidewall portions ( 2 ). The tire is embedded with a transponder ( 20 ) covered with a covering layer ( 23 ). A glass transition temperature (Tg) of the covering layer ( 23 ) is in a range of from −70° C. to −45° C.
1 . A pneumatic tire, comprising:
a tread portion extending in a tire circumferential direction and having an annular shape;
a pair of sidewall portions disposed on both sides of the tread portion; and
a pair of bead portions disposed on an inner side in a tire radial direction of the sidewall portions;
the tire being embedded with a transponder covered with a covering layer; and
a glass transition temperature Tg of the covering layer being in a range of from −70° C. to −45° C.
2 . The pneumatic tire according to claim 1 , wherein a storage modulus E′c (−20° C.) at −20° C. of the covering layer is in a range of from 3 MPa to 17 MPa.
3 . The pneumatic tire according to claim 1 , wherein the covering layer has a relative dielectric constant of 7 or less.
4 . The pneumatic tire according to claim 1 , wherein
the transponder is embedded on an outer side in a tire width direction of a carcass layer, and
a storage modulus E′c (−20° C.) at −20° C. of the covering layer and a storage modulus E′out (−20° C.) at −20° C. of a rubber member having a largest storage modulus at 20° C. of rubber members located on the outer side in the tire width direction of the transponder satisfy a relationship 0.1≤E′c (−20° C.)/E′out (−20° C.)≤1.5.
5 . The pneumatic tire according to claim 1 , wherein the covering layer is formed of a rubber or an elastomer and 20 phr or more of a white filler.
6 . The pneumatic tire according to claim 5 , wherein the white filler comprises from 20 phr to 55 phr of calcium carbonate.
7 . The pneumatic tire according to claim 1 , wherein a center of the transponder is disposed 10 mm or more away in the tire circumferential direction from a splice portion of a tire component.
8 . The pneumatic tire according to claim 1 , wherein the transponder is disposed between a position 15 mm away from and on an outer side in the tire radial direction of an upper end of a bead core of the bead portion and a tire maximum width position.
9 . The pneumatic tire according to claim 1 , wherein a distance between a cross-sectional center of the transponder and a tire surface is 1 mm or more.
10 . The pneumatic tire according to claim 1 , wherein a thickness of the covering layer ranges from 0.5 mm to 3.0 mm.
11 . The pneumatic tire according to claim 1 , wherein the transponder comprises an IC substrate that stores data and an antenna that transmits and receives data, and the antenna has a helical shape.
12 . The pneumatic tire according to claim 2 , wherein the covering layer has a relative dielectric constant of 7 or less.
13 . The pneumatic tire according to claim 12 , wherein
the transponder is embedded on an outer side in a tire width direction of a carcass layer, and
a storage modulus E′c (−20° C.) at −20° C. of the covering layer and a storage modulus E′out (−20° C.) at −20° C. of a rubber member having a largest storage modulus at 20° C. of rubber members located on the outer side in the tire width direction of the transponder satisfy a relationship 0.1≤E′c (−20° C.)/E′out (−20° C.)≤1.5.
14 . The pneumatic tire according to claim 13 , wherein the covering layer is formed of a rubber or an elastomer and 20 phr or more of a white filler.
15 . The pneumatic tire according to claim 14 , wherein the white filler comprises from 20 phr to 55 phr of calcium carbonate.
16 . The pneumatic tire according to claim 15 , wherein a center of the transponder is disposed 10 mm or more away in the tire circumferential direction from a splice portion of a tire component.
17 . The pneumatic tire according to claim 16 , wherein the transponder is disposed between a position 15 mm away from and on an outer side in the tire radial direction of an upper end of a bead core of the bead portion and a tire maximum width position.
18 . The pneumatic tire according to claim 17 , wherein a distance between a cross-sectional center of the transponder and a tire surface is 1 mm or more.
19 . The pneumatic tire according to claim 18 , wherein a thickness of the covering layer ranges from 0.5 mm to 3.0 mm.
20 . The pneumatic tire according to claim 19 , wherein the transponder comprises an IC substrate that stores data and an antenna that transmits and receives data, and the antenna has a helical shape.