Golf club head

Abstract

A golf club head comprises a face portion having a club face for hitting a ball and comprising a composite part. The composite part has a layered structure comprising: a thin surficial layer made of a metal material for contacting with a ball; an intermediate elastic layer composed of a rubber-like elastic material disposed inside the thin surficial layer; and a back support layer made of a metal material disposed inside the intermediate elastic layer. In a front view of the club head, the intermediate elastic layer includes a center of the club face. The edge surface of the intermediate elastic layer is at least partially exposed at the outer surface of the club head.

1 . A golf club head comprising
 a face portion having a club face for hitting a ball and comprising a composite part,   
       wherein
 the composite part has a layered structure comprising: a thin surficial layer made of a metal material for contacting with a ball; an intermediate elastic layer composed of a rubber-like elastic material disposed inside the thin surficial layer; and a back support layer made of a metal material disposed inside the intermediate elastic layer, 
 in a front view of the club head, the intermediate elastic layer includes a center of the club face, and 
 an edge surface of the intermediate elastic layer is at least partially exposed at the outer surface of the club head. 
 
     
     
         2 . The golf club head according to  claim 1 , wherein
 in the front view of the club head, the intermediate elastic layer extends in a first direction, and   the edge surface of the intermediate elastic layer exposed at the outer surface of the club head is positioned in the vicinity of one end or alternatively each end of the intermediate elastic layer in the first direction.   
     
     
         3 . The golf club head according to  claim 2 , wherein
 the composite part comprises a side support wall for preventing the intermediate elastic layer from running out in a direction orthogonal to the first direction.   
     
     
         4 . The golf club head according to  claim 1 , wherein the thickness of the thin surficial layer is 0.1 to 1.0 mm. 
     
     
         5 . The golf club head according to  claim 1 , wherein the Young's modulus of the rubber-like elastic material is 10 MPa to 1 GPa. 
     
     
         6 . The golf club head according to  claim 1 , wherein the Young's modulus of the rubber-like elastic material is 100 MPa to 500 MPa. 
     
     
         7 . The golf club head according to  claim 2 , wherein the first direction is the up-and-down direction of the club head. 
     
     
         8 . The golf club head according to  claim 2 , wherein the first direction is the toe-heel direction of the club head. 
     
     
         9 . The golf club head according to  claim 2 , wherein
 the first direction is an oblique direction inclined downwards towards the heel from the toe of the club head.   
     
     
         10 . The golf club head according to  claim 1 , wherein the natural frequency fc in a primary mode of the club head when the center of the club face is supported or fixed is 800 to 1600 Hz. 
     
     
         11 . The golf club head according to  claim 1 , wherein the ratio feg/fc is 1.0 to 1.3, wherein
 fc is the natural frequency in a primary mode of the club head when the center of the club face is supported or fixed, and   feg is the natural frequency in a primary mode of the club head when a peripheral edge portion of the club face corresponding to the composite part is supported or fixed.