Pneumatic tire and method of manufacturing tire vulcanization mold

Abstract

A pneumatic tire has an outer surface with an arithmetical mean roughness Ra in the range of 0.1 μm to 0.6 μm when a reference length Lr is 20 μm, wherein the outer surface has an irregularity diameter in the range of 40-230 μm and an irregularity depth in the range of 3-22 μm. A method of manufacturing a tire vulcanization mold includes propelling spherical abrasive grains onto the surface of the mold under the condition that a propelling pressure is in the range of 0.1-0.6 MPa, so as to process the surface of the mold.

1 . A method of manufacturing a tire vulcanization mold, the mold having a first portion corresponding to a tire tread portion, and having second and third portions corresponding to tire side portions, each of the first, second and third portions having a surface, the method comprising:
 propelling spherical abrasive grains onto at least one of the surfaces of the first, second and third portions under the condition that a propelling pressure is in the range of 0.1-0.6 MPa, so as to process the surface of the mold.   
     
     
         2 . The method of manufacturing a tire vulcanization mold according to  claim 1 , wherein the abrasive grains with a grain diameter of not more than 850 μm are propelled onto the surface of the mold. 
     
     
         3 . The method of manufacturing a tire vulcanization mold according to  claim 1 , wherein the abrasive grains are propelled onto the surface of the mold at the propelling pressure of 0.1 MPa to 0.2 MPa. 
     
     
         4 . The method of manufacturing a tire vulcanization mold according to  claim 2 , wherein the abrasive grains are propelled onto the surface of the mold at the propelling pressure of 0.1 MPa to 0.2 MPa.