Pneumatic tire

Abstract

The present invention relates to a pneumatic tire 1 in which turbulent-flow generating projections 10 each extending from an inner circumference side to an outer circumference side are provided on a outer circumferential face 3 a which is tire surface of tire side portion 3 at intervals in a tire circumferential direction. Each of the turbulent-flow generating projections 10 includes an edge portion 10 g when being viewed in a cross-sectional shape taken along a direction perpendicular to an extending direction thereof, and a front wall angle θ formed between a front wall face 10 a of each turbulent-flow generating projection 10 and the tire surface (outer circumferential face 3 a ) is set in the range of 70° to 110°, the front wall face being hit by an airflow.

1 . A pneumatic tire in which turbulent-flow generating projections each extending from an inner circumference side to an outer circumference side are provided on a tire surface at intervals in a tire circumferential direction, wherein:
 each of the turbulent-flow generating projections includes an edge portion when being viewed in a cross-sectional shape taken along a direction perpendicular to an extending direction thereof; and   a front wall angle formed between a front wall face of each turbulent-flow generating projection and the tire surface is set in the range of 70° to 110°, the front wall face being hit by an airflow,   wherein each of the turbulent-flow generating projections is provided in a groove formed in a tread portion.   
     
     
         2 . The pneumatic tire according to  claim 1 , wherein the cross-sectional shape of each turbulent-flow generating projection is left-right symmetric. 
     
     
         3 . The pneumatic tire according to  claim 1 , wherein a rear wall angle formed between a rear wall face and the tire surface is set to 90° or more, the rear wall face being located in the rear of the front wall face with respect to a tire rotation direction. 
     
     
         4 . The pneumatic tire according to  claim 1 , wherein a lower side width of the cross-sectional shape of the turbulent-flow generating projection is set in the range of 0.5 mm to 5 mm. 
     
     
         5 . The pneumatic tire according to  claim 1 , wherein a relationship of 0.03≦h/R 1/2 ≦0.64 is satisfied where: h denotes a height of the turbulent-flow generating projection; and R, a tire radius. 
     
     
         6 . The pneumatic tire according to  claim 5 , wherein a relationship of 0.05≦h/R 1/2 ≦0.64 is satisfied where: h denotes a height of the turbulent-flow generating projection; and R, a tire radius. 
     
     
         7 . The pneumatic tire according to  claim 1 , wherein the cross-sectional shape of the turbulent-flow generating projection is trapezoidal. 
     
     
         8 . The pneumatic tire according to  claim 1 , wherein a through-hole is formed in the turbulent-flow generating projection, the through-hole penetrating in a direction perpendicular to the extending direction. 
     
     
         9 . The pneumatic tire according to  claim 1 , wherein relationships of 1.0≦p/h≦50.0 and 1.0≦(p−w)/w≦100.0 are satisfied where: h denotes the height of each of the turbulent-flow generating projections; p denotes a pitch of adjacent ones of the turbulent-flow generating projections in a tire rotation direction; and w denotes a lower side width of each of the turbulent-flow generating projections in the cross-sectional shape. 
     
     
         10 . The pneumatic tire according to  claim 1 , wherein a tilt angle θ is set in the range of −70°≦θ≦70°, the tilt angle θ being an angle at which the turbulent-flow generating projection tilts to a tire radial direction. 
     
     
         11 . The pneumatic tire according to  claim 1 , wherein a sidewall reinforcing layer which reinforces the tire side portion is provided in the tire side portion. 
     
     
         12 . The pneumatic tire according to  claim 1 , wherein the pneumatic tire is a heavy-duty tire.