Pneumatic tire having directional tread pattern

Abstract

The present invention provides a pneumatic tire which can obtain a high wet drainage performance, roadholding ability, and wear-resistant property without sacrificing other capabilities A directional pattern is formed by a circumferential wide major groove, a first narrow circumferential minor groove, a second narrow circumferential minor groove, a first transverse groove, a second transverse groove, and a third transverse groove. The circumferential wide major groove is provided in a center region in a tire width direction of a tread. The first narrow circumferential minor groove is arranged on the outside in a tire axis direction of the circumferential wide major groove. The second narrow circumferential minor groove is arranged on the outside in the tire axis direction of the first narrow circumferential minor groove. The first transverse groove is extended from a tread end and coupled to the circumferential wide major groove. The second transverse groove is arranged between the first transverse grooves, and the second transverse groove is extended from the tread end and terminated while not coupled to the circumferential wide major groove. The third transverse groove is arranged between the first transverse groove and the second transverse groove, and the third transverse groove is extended from the tread end and terminated between the first narrow circumferential minor groove and the second narrow circumferential minor groove.

What is claimed is: 
     
         1 . A pneumatic tire comprising a plurality of grooves including a transverse groove in a tread, the transverse groove being extended while inclined with respect to a tire circumferential direction, wherein,
 a bottom raising portion which raises the transverse groove is formed on one side of the transverse groove in a tire width direction, and the transverse groove is substantially opened to and terminated in another groove that is adjacent to the transverse groove on the one side in the tire width direction,   the transverse groove is completely opened to one of other grooves which is adjacent to the transverse groove on the other side in the tire width direction or the transverse groove is completely opened to a tread end, and   an inclined surface is formed as a grove bottom surface in the bottom raising portion, a depth of the transverse groove to the inclined surface being gradually decreased from the other side to a top portion of the bottom raising portion in the tire width direction.   
     
     
         2 . The pneumatic tire of  claim 1 , wherein the grooves comprise a plurality of the transverse grooves formed at substantially equal intervals. 
     
     
         3 . The pneumatic tire of  claim 1 , wherein a groove length of a groove portion which has the inclined surface as a groove bottom surface is set in the range of 5 to 100% of a groove length of the transverse groove having the groove portion. 
     
     
         4 . The pneumatic tire of  claim 1 , wherein the tread includes a circumferential major groove which is extended along the tire circumferential direction,
 a cross section of the bottom raising portion in a longitudinal direction of the groove is formed in a chevron shape, a one side inclined surface is formed as the groove bottom surface at the bottom raising portion, the groove depth being gradually increased from the top portion to the one side at the one side inclined surface in tire width direction,   a land portion adjacent to the transverse groove has a edge portion at the one side, the edge portion having an edge surface which is provided along the circumferential major groove and is chamfered in a tapered shape so that the edge surface forms the same surface as the one side inclined surface, and   inclination angles of the one side inclined surface and the edge surface range from 30 to 60° with respect to a line parallel to a tire radial direction.