Hollow golf club head

Abstract

This invention provides a hollow golf club head comprising a face portion, a crown portion, a sole portion, a side portion, and a hosel portion. A crown projecting portion in which the crown portion partly projects upward is formed at a position including a face center in the face-side region of the crown portion, and the thickness of the crown projecting portion gradually decreases toward the back.

1 . A hollow golf club head comprising a face portion, a crown portion, a sole portion, a side portion, and a hosel portion, wherein
 a crown projecting portion in which the crown portion partly projects upward is formed at a position including a face center in a face-side region of the crown portion, and   a thickness of the crown projecting portion gradually decreases toward a back.   
     
     
         2 . The head according to  claim 1 , wherein a face-side end portion of the crown projecting portion is continuous with an upper edge portion of the face portion. 
     
     
         3 . The head according to  claim 1 , wherein a thickness of a face-side end portion of the crown projecting portion is 1.5 to 3.0 mm, and a thickness of a back-side end portion is 0.5 to 1.2 mm. 
     
     
         4 . The head according to  claim 1 , wherein a projection height of a back-side end portion of the crown projecting portion from a crown surface is 1 to 4 mm. 
     
     
         5 . The head according to  claim 1 , wherein a ratio [(a/A)×100%] of a distance a of the crown projecting portion in a toe-to-heel direction to a distance A of the crown portion in the toe-to-heel direction is 20% to 60%. 
     
     
         6 . The head according to  claim 1 , wherein a ratio [(b/B)×100%] of a distance b of the crown projecting portion in a face-to-back direction to a distance B of the crown portion in the face-to-back direction is 10% to 40%. 
     
     
         7 . A hollow golf club head comprising a face portion, a crown portion, a sole portion, a side portion, and a hosel portion, wherein
 a crown projecting portion in which the crown portion partly projects upward is provided at a position including a face center in a face-side region of the crown portion, and   the crown projecting portion is formed using a material having a Young's modulus lower than a Young's modulus of a portion other than the crown projecting portion in the crown portion.   
     
     
         8 . The head according to  claim 7 , wherein the portion other than the crown projecting portion in the crown portion is formed using a material having a Young's modulus of not less than 100 GPa, and the crown projecting portion is formed using a material having a Young's modulus of 65 to 95 GPa. 
     
     
         9 . The head according to  claim 7 , wherein a difference between the Young's modulus of the material which forms the portion other than the crown projecting portion in the crown portion and the Young's modulus of the material which forms the crown projecting portion is 15 to 50 GPa. 
     
     
         10 . The head according to  claim 7 , wherein the portion other than the crown projecting portion in the crown portion is formed using a first high-strength titanium alloy, and the crown projecting portion is formed using a second high-strength titanium alloy having a Young's modulus lower than a Young's modulus of the first high-intensity titanium alloy. 
     
     
         11 . The head according to  claim 7 , wherein a face-side end portion of the crown projecting portion is continuous with an upper edge portion of the face portion. 
     
     
         12 . The head according to  claim 7 , wherein a projection height of a back-side end portion of the crown projecting portion from a crown surface is 1 to 4 mm. 
     
     
         13 . The head according to  claim 7 , wherein a ratio [(a/A)×100%] of a distance a of the crown projecting portion in a toe-to-heel direction to a distance A of the crown portion in the toe-to-heel direction is 20% to 60%. 
     
     
         14 . The head according to  claim 7 , wherein a ratio [(b/B)×100%] of a distance b of the crown projecting portion in a face-to-back direction to a distance B of the crown portion in the face-to-back direction is 10% to 40%. 
     
     
         15 . The head according to  claim 7 , wherein a thickness of the crown projecting portion gradually decreases toward a back. 
     
     
         16 . The head according to  claim 15 , wherein a thickness of a face-side end portion of the crown projecting portion is 1.5 to 3.0 mm, and a thickness of a back-side end portion is 0.5 to 1.2 mm.