Golf club head

Abstract

[Object] It is an object of the present invention to provide a golf club head being lightweight and having a high strength. [Solving Means] A head 2 includes a face 4 , a sole 8 , and a crown 6 . The face 4 includes a face surface fs and a face back surface fr. A plurality of projections (A) are provided on the face back surface fr. The projections (A) are point-like in a planar view. An optional first direction and a second direction orthogonal to the first direction are defined in the planar view. Preferably, arrangement regularity of the projections (A) in the second direction is higher than arrangement regularity of the projections (A) in the first direction. Preferably, the first direction is a longitudinal direction; and the second direction is a lateral direction.

1 . A golf club head comprising: a face; a sole; and a crown,
 wherein the face includes a face surface and a face back surface;   
       a plurality of projections (A) are provided on the face back surface; and
 the projections (A) are point-like in a planar view. 
 
     
     
         2 . The golf club head according to  claim 1 , wherein if an optional first direction and a second direction orthogonal to the first direction are defined in the planar view, arrangement regularity of the projections (A) in the second direction is higher than arrangement regularity of the projections (A) in the first direction. 
     
     
         3 . The golf club head according to  claim 2 , wherein the first direction is a longitudinal direction; and the second direction is a lateral direction. 
     
     
         4 . The golf club head according to  claim 1 , wherein if an area of each of the projections (A) in the planar view is defined as Ma, the two or more kinds of projections (A) have areas Ma substantially different from each other. 
     
     
         5 . The golf club head according to  claim 1 , wherein the projections (A) include a projection (A 1 ) of which the area Ma is an area Ma 1 , a projection (A 2 ) of which the area Ma is an area Ma 2 , and a projection (A 3 ) of which the area Ma is an area Ma 3 ;
 the area Ma 1  is greater than the area Ma 2 , and the area Ma 2  is greater than the area Ma 3 ;   the projection (A 2 ) is disposed on a face peripheral side with respect to the projection (A 1 ) in the first direction; and   the projection (A 3 ) is disposed on a face peripheral side with respect to the projection (A 2 ) in the first direction.   
     
     
         6 . The golf club head according to  claim 1 , wherein the projections (A) include a projection (A 1 ) of which the area Ma is an area Ma 1 , a projection (A 2 ) of which the area Ma is an area Ma 2 , and a projection (A 3 ) of which the area Ma is an area Ma 3 ;
 the area Ma 1  is greater than the area Ma 2 , and the area Ma 2  is greater than the area Ma 3 ;   if a longitudinal distance between a periphery of the face back surface and the projection (A 1 ) is defined as a 1 ; a longitudinal distance between the periphery of the face back surface and the projection (A 2 ) is defined as a 2 ; a longitudinal distance between the periphery of the face back surface and the projection (A 3 ) is defined as a 3 ; an average value of the distances a 1  is defined as Av 1 ; an average value of the distances a 2  is defined as Av 2 ; and an average value of the distances a 3  is defined as Av 3 ,   the average value Av 1  is greater than the average value Av 2 ; and the average value Av 2  is greater than the average value Av 3 .   
     
     
         7 . The golf club head according to  claim 1 , wherein an area Ma of each of the projections (A) is 3 mm 2  or greater and 40 mm 2  or less in the planar view; and a height Ha of each of the projections (A) is 0.03 mm or greater and 0.2 mm or less. 
     
     
         8 . The golf club head according to  claim 1 , wherein a plurality of projection arrangement regions are provided on the face back surface; and
 arrangement regularity in the second direction is higher than arrangement regularity in the first direction in at least one of the projection arrangement regions.   
     
     
         9 . The golf club head according to  claim 1 ,
 wherein a plurality of projection arrangement regions are provided on the face back surface;   a middle projection arrangement region including a face back surface center is present as one of the projection arrangement regions; and   arrangement regularity in the second direction is higher than arrangement regularity in the first direction in the middle projection arrangement region.   
     
     
         10 . The golf club head according to  claim 1 , wherein the golf club head is manufactured by joining a face member and another member;
 the face member is manufactured by forging;   the forging includes a preceding forging step and a subsequent forging step;   projections (B) higher than the projections (A) are formed on the face back surface in the preceding forging step; and   the projections (A) are formed by crushing the projections (B) in the subsequent forging step.   
     
     
         11 . The golf club head according to  claim 2 , wherein if an area of each of the projections (A) in the planar view is defined as Ma, the two or more kinds of projections (A) have areas Ma substantially different from each other. 
     
     
         12 . The golf club head according to  claim 3 , wherein if an area of each of the projections (A) in the planar view is defined as Ma, the two or more kinds of projections (A) have areas Ma substantially different from each other. 
     
     
         13 . The golf club head according to  claim 2 , wherein the projections (A) include a projection (A 1 ) of which the area Ma is an area Ma 1 , a projection (A 2 ) of which the area Ma is an area Ma 2 , and a projection (A 3 ) of which the area Ma is an area Ma 3 ;
 the area Ma 1  is greater than the area Ma 2 , and the area Ma 2  is greater than the area Ma 3 ;   the projection (A 2 ) is disposed on a face peripheral side with respect to the projection (A 1 ) in the first direction; and   the projection (A 3 ) is disposed on a face peripheral side with respect to the projection (A 2 ) in the first direction.   
     
     
         14 . The golf club head according to  claim 3 , wherein the projections (A) include a projection (A 1 ) of which the area Ma is an area Ma 1 , a projection (A 2 ) of which the area Ma is an area Ma 2 , and a projection (A 3 ) of which the area Ma is an area Ma 3 ;
 the area Ma 1  is greater than the area Ma 2 , and the area Ma 2  is greater than the area Ma 3 ;   the projection (A 2 ) is disposed on a face peripheral side with respect to the projection (A 1 ) in the first direction; and   the projection (A 3 ) is disposed on a face peripheral side with respect to the projection (A 2 ) in the first direction.   
     
     
         15 . The golf club head according to  claim 4 , wherein the projections (A) include a projection (A 1 ) of which the area Ma is an area Ma 1 , a projection (A 2 ) of which the area Ma is an area Ma 2 , and a projection (A 3 ) of which the area Ma is an area Ma 3 ;
 the area Ma 1  is greater than the area Ma 2 , and the area Ma 2  is greater than the area Ma 3 ;   the projection (A 2 ) is disposed on a face peripheral side with respect to the projection (A 1 ) in the first direction; and   the projection (A 3 ) is disposed on a face peripheral side with respect to the projection (A 2 ) in the first direction.   
     
     
         16 . The golf club head according to  claim 2 , wherein the projections (A) include a projection (A 1 ) of which the area Ma is an area Ma 1 , a projection (A 2 ) of which the area Ma is an area Ma 2 , and a projection (A 3 ) of which the area Ma is an area Ma 3 ;
 the area Ma 1  is greater than the area Ma 2 , and the area Ma 2  is greater than the area Ma 3 ;   if a longitudinal distance between a periphery of the face back surface and the projection (A 1 ) is defined as a 1 ; a longitudinal distance between the periphery of the face back surface and the projection (A 2 ) is defined as a 2 ; a longitudinal distance between the periphery of the face back surface and the projection (A 3 ) is defined as a 3 ; an average value of the distances a 1  is defined as Av 1 ; an average value of the distances a 2  is defined as Av 2 ; and an average value of the distances a 3  is defined as Av 3 ,   the average value Av 1  is greater than the average value Av 2 ; and the average value Av 2  is greater than the average value Av 3 .   
     
     
         17 . The golf club head according to  claim 3 , wherein the projections (A) include a projection (A 1 ) of which the area Ma is an area Ma 1 , a projection (A 2 ) of which the area Ma is an area Ma 2 , and a projection (A 3 ) of which the area Ma is an area Ma 3 ;
 the area Ma 1  is greater than the area Ma 2 , and the area Ma 2  is greater than the area Ma 3 ;   if a longitudinal distance between a periphery of the face back surface and the projection (A 1 ) is defined as a 1 ; a longitudinal distance between the periphery of the face back surface and the projection (A 2 ) is defined as a 2 ; a longitudinal distance between the periphery of the face back surface and the projection (A 3 ) is defined as a 3 ; an average value of the distances a 1  is defined as Av 1 ; an average value of the distances a 2  is defined as Av 2 ; and an average value of the distances a 3  is defined as Av 3 ,   the average value Av 1  is greater than the average value Av 2 ; and the average value Av 2  is greater than the average value Av 3 .   
     
     
         18 . The golf club head according to  claim 4 , wherein the projections (A) include a projection (A 1 ) of which the area Ma is an area Ma 1 , a projection (A 2 ) of which the area Ma is an area Ma 2 , and a projection (A 3 ) of which the area Ma is an area Ma 3 ;
 the area Ma 1  is greater than the area Ma 2 , and the area Ma 2  is greater than the area Ma 3 ;   if a longitudinal distance between a periphery of the face back surface and the projection (A 1 ) is defined as a 1 ; a longitudinal distance between the periphery of the face back surface and the projection (A 2 ) is defined as a 2 ; a longitudinal distance between the periphery of the face back surface and the projection (A 3 ) is defined as a 3 ; an average value of the distances a 1  is defined as Av 1 ; an average value of the distances a 2  is defined as Av 2 ; and an average value of the distances a 3  is defined as Av 3 ,   the average value Av 1  is greater than the average value Av 2 ; and the average value Av 2  is greater than the average value Av 3 .   
     
     
         19 . The golf club head according to  claim 5 , wherein the projections (A) include a projection (A 1 ) of which the area Ma is an area Ma 1 , a projection (A 2 ) of which the area Ma is an area Ma 2 , and a projection (A 3 ) of which the area Ma is an area Ma 3 ;
 the area Ma 1  is greater than the area Ma 2 , and the area Ma 2  is greater than the area Ma 3 ;   if a longitudinal distance between a periphery of the face back surface and the projection (A 1 ) is defined as a 1 ; a longitudinal distance between the periphery of the face back surface and the projection (A 2 ) is defined as a 2 ; a longitudinal distance between the periphery of the face back surface and the projection (A 3 ) is defined as a 3 ; an average value of the distances a 1  is defined as Av 1 ; an average value of the distances a 2  is defined as Av 2 ; and an average value of the distances a 3  is defined as Av 3 ,   the average value Av 1  is greater than the average value Av 2 ; and the average value Av 2  is greater than the average value Av 3 .   
     
     
         20 . The golf club head according to  claim 2 , wherein an area Ma of each of the projections (A) is 3 mm 2  or greater and 40 mm 2  or less in the planar view; and a height Ha of each of the projections (A) is 0.03 mm or greater and 0.2 mm or less.