Pneumatic tire

Abstract

A pneumatic tire 1 comprises a carcass 6 extending between bead cores of bead portions via a tread portion 2 and sidewall portions, and a belt layer 7 arranged on an outer side in a tire radial direction of the carcass 6 and inside of the tread portion 2 . The pneumatic tire 1 further comprises a damping rubber body 30 arranged between the carcass 6 and the belt layer 7 , and a noise damper 20 arranged on an inner cavity surface of the tread portion 2 . A width W 1 in a tire axial direction of the damping rubber body 30 is in a range of from 60% to 130% of a width W 2 in the tire axial direction of the belt layer 7 , and a water absorption rate of the noise damper 20 is in a range of from 10% to 25%.

1 . A pneumatic tire comprising a carcass extending between bead cores of bead portions via a tread portion and sidewall portions, a belt layer arranged on an outer side in a tire radial direction of the carcass and inside of the tread portion, and a porous noise damper arranged on an inner cavity surface of the tread portion, wherein
 a water absorption rate of the noise damper is in a range of from 10% to 25%, the water absorption rate being calculated by a following formula (1):
   water absorption rate (%)=weight change before and after immersion ( g )/volume at 50% compression (cm3)×100  (1).
 
   
     
     
         2 . The pneumatic tire according to  claim 1 , wherein
 density of the noise damper is in a range of from 10 to 40 kg/m3.   
     
     
         3 . The pneumatic tire according to  claim 1 , wherein
 volume V 1  of the noise damper is in a range of from 0.4% to 30% of total volume V 2  of a tire inner cavity.   
     
     
         4 . The pneumatic tire according to  claim 1 , wherein
 tensile strength of the noise damper is in a range of from 70 to 115 kPa.   
     
     
         5 . The pneumatic tire according to  claim 1 , wherein
 a loss tangent tan δ at 0 degree Celsius of a tread rubber arranged on an outer side in the tire radial direction of the belt layer is not less than 0.4 and the loss tangent tan δ at 70 degrees Celsius of the tread rubber is not more than 0.2.   
     
     
         6 . The pneumatic tire according to  claim 1 , wherein
 a tread rubber arranged on an outer side in the tire radial direction of the belt layer is a rubber composition having a value not less than 20, the value being calculated by a following formula:
   (1.4×carbon black content (phr)+silica content (phr))/sulfur content (phr).
 
   
     
     
         7 . The pneumatic tire according to  claim 1  further comprising a damping rubber body arranged inside of the tread portion. 
     
     
         8 . The pneumatic tire according to  claim 7 , wherein
 a width W 1  in a tire axial direction of the damping rubber body is in a range of from 60% to 130% of a width W 2  in the tire axial direction of the belt layer.   
     
     
         9 . The pneumatic tire according to  claim 7 , wherein
 the damping rubber body is arranged between the carcass and the belt layer.   
     
     
         10 . The pneumatic tire according to  claim 7  further comprising a band layer arranged on an outer side in the tire radial direction of the belt layer and inside of the tread portion, wherein
 the damping rubber body is arranged between the belt layer and the band layer. 
 
     
     
         11 . The pneumatic tire according to  claim 7  further comprising a band layer arranged on an outer side in the tire radial direction of the belt layer and inside of the tread portion, wherein
 the damping rubber body is arranged on an outer side in the tire radial direction of the band layer. 
 
     
     
         12 . The pneumatic tire according to  claim 7 , wherein
 thickness in the tire radial direction of the damping rubber body is not less than 0.3 mm.   
     
     
         13 . The pneumatic tire according to  claim 7 , wherein
 relationship between hardness H 1  of the damping rubber body and hardness H 2  of a tread rubber arranged on an outer side in the tire radial direction of the belt layer satisfies a following expression:
   0.5≤ H 1/ H 2≤1.0.