Golf Club Head

Abstract

A golf club head is provided, on a curved outer surface of a crown portion, with a protrusion. The protrusion does not constitute a first profile line of the head in the front view of the head under its reference state. The protrusion constitutes a second contour line of the head in a side view of the head its a vertical state viewed from the heel side. In a top view of the head under the reference state, the protrusion has a boundary point which is farthest from a third profile line of the crown portion in a direction orthogonal to the third profile line toward a crown apex side, and the distance from the third profile line to the boundary point is not more than 20% of the distance from the third profile line to the crown apex through the boundary point.

1 . A golf club head which has a cavity therein, and, in a reference state of the golf club head placed on a horizontal plane at its specified lie angle and loft angle, comprising:
 a face portion having a club face for hitting a golf ball;   a crown portion having a curved surface which is convex toward an upper side to define a crown apex;   a hosel defining a club shaft axis; and   a heel,   
       wherein
 the curved surface of the crown portion is provided with a protrusion so that the protrusion does not constitute a first profile line which is an outer contour line of the golf club head in a front view of the golf club head under the reference state viewed from a club face side of the golf club head, 
 
       the protrusion constitutes a second contour line which is an outer contour line of the golf club head in a side view of the golf club head under its vertical state viewed from a heel side of the golf club head in which the above-said club shaft axis is perpendicular to the above-said horizontal plane and a face angle is 0 degrees, 
       in a plan view of the golf club head viewed from above the golf club head under the reference state, the protrusion has a boundary point located at a position farthest from a third profile line which is an outer contour line of the crown portion, toward the crown apex in a direction perpendicular to the third profile line, and 
       a distance B from the third profile line to the boundary point is not more than 20% of a distance A from the crown apex to the third profile line via the boundary point. 
     
     
         2 . The golf club head according to  claim 1 , wherein
 the distance B from the third profile line to the boundary point is not less than 12% of the distance A from the crown apex to the third profile line via the boundary point.   
     
     
         3 . The golf club head according to  claim 1 , wherein
 the protrusion constitutes the third profile line in the plan view.   
     
     
         4 . The golf club head according to  claim 2 , wherein
 the protrusion constitutes the third profile line in the plan view.   
     
     
         5 . The golf club head according to  claim 1 , wherein
 the protrusion does not constitute the third profile line in the plan view.   
     
     
         6 . The golf club head according to  claim 2 , wherein
 the protrusion does not constitute the third profile line in the plan view.   
     
     
         7 . The golf club head according to  claim 1 , wherein
 the protrusion includes a first protrusion having a first apex and a second protrusion having a second apex.   
     
     
         8 . The golf club head according to  claim 4 , wherein
 the protrusion includes a first protrusion having a first apex and a second protrusion having a second apex.   
     
     
         9 . The golf club head according to  claim 6 , wherein
 the protrusion includes a first protrusion having a first apex and a second protrusion having a second apex.   
     
     
         10 . The golf club head according to  claim 9 , wherein
 the first protrusion and the second protrusion are connected to each other so that a recess is formed between them.   
     
     
         11 . The golf club head according to  claim 9 , wherein
 the first protrusion has three wall surfaces which intersect at the first apex.   
     
     
         12 . The golf club head according to  claim 10 , wherein
 the first protrusion has three wall surfaces which intersect at the first apex.   
     
     
         13 . The golf club head according to  claim 11 , wherein
 the second protrusion has three wall surfaces which intersect at the second apex.   
     
     
         14 . The golf club head according to  claim 12 , wherein
 the second protrusion has three wall surfaces which intersect at the second apex.   
     
     
         15 . The golf club head according to  claim 1 , wherein
 the protrusion has an upper surface, and   a protruding height of the protrusion on the upper surface increases as the measuring position approaches the third profile line.   
     
     
         16 . The golf club head according to  claim 15 , wherein
 the upper surface has a quadrilateral shape.   
     
     
         17 . The golf club head according to  claim 15 , wherein
 the upper surface has a triangular shape.   
     
     
         18 . The golf club head according to  claim 1 , wherein
 in the plan view, a total area St of the protrusion is in a range from 5% to 15% of an area Sh of a part of the crown portion located on a heel side of a face center.   
     
     
         19 . The golf club head according to  claim 1 , wherein
 in the crown portion, at least a part of the protrusion has a wall thickness larger than an average wall thickness of the crown portion.   
     
     
         20 . The golf club head according to  claim 1 , wherein
 a protruding height of the protrusion is not more than 5 mm from the curved surface of the crown portion.