Pneumatic tire
A pneumatic tire includes: 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 is embedded with a transponder covered with a covering layer. A modulus M50 (0° C.) at 50% deformation at 0° C. of the covering layer is in a range of from 0.5 MPa to 2.0 MPa, and a modulus M50 (−20° C.) at 50% deformation at −20° C. of the covering layer and the modulus M50 (0° C.) at 50% deformation at 0° C. of the covering layer satisfy a relationship 1.0<M50 (−20° C.)/M50 (0° C.)≤2.5.
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;
a modulus M50 (0° C.) at 50% deformation at 0° C. of the covering layer being in a range of from 0.5 MPa to 2.0 MPa; and
a modulus M50 (−20° C.) at 50% deformation at −20° C. of the covering layer and the modulus M50 (0° C.) at 50% deformation at 0° C. of the covering layer satisfying a relationship 1.0<M50 (−20° C.)/M50 (0° C.)≤2.5.
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 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.
4. The pneumatic tire according to claim 1 , wherein the covering layer has a relative dielectric constant of 7 or less.
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.