Method of designing golf club and golf club head

Abstract

A method for designing a golf club head by using a computer. A golf club head model in which the rear surface of a face part is provided with reinforcing ribs and a golf ball model to be analyzed by using a finite element method (FEM) are prepared. Conditions including the positions of the reinforcing ribs and the configurations thereof including the sectional areas and heights are adjusted to set the maximum value of the Mises stresses generated by the collision between the golf ball model and the golf club head model at any off-center positions of said front surface of said face part thereof to less than 1.3 times the maximum value of the Mises stress generated by the collision between the golf ball model and the golf club head model at the center of said front surface of said face part thereof.

1 . A method of designing a golf club head by using a computer, comprising the steps of: 
 preparing a ball model and a club head model obtained by dividing a golf ball and a golf club head into a plurality of finite elements respectively, wherein said club head model is provided with a central reinforcing rib formed at a central portion of a rear surface of a face part thereof and a plurality of belt-shaped reinforcing ribs extended radially from said central reinforcing rib toward a peripheral edge of said rear surface of said face part;    executing simulation of collision between said ball model and said club head model at a plurality of positions of a front surface of said face part thereof to determine a Mises stress generated at each of said collision positions; and    changing setting conditions of said central reinforcing rib and said belt-shaped reinforcing ribs to set a maximum value of Mises stresses generated at off-center positions of said front surface of said face part to less than 1.3 times a maximum value of a Mises stress generated at a center of said front surface of said face part.    
   
   
       2 . The method according to  claim 1 , wherein not less than four nor more than 10 belt-shaped reinforcing ribs are formed on said rear surface of said face part; and said setting conditions of said belt-shaped reinforcing ribs include a number of said belt-shaped reinforcing ribs, positions thereof, sectional areas thereof, heights thereof, and widths thereof.  
   
   
       3 . The method according to  claim 1 , wherein said club head model is a wood club head model; said reinforcing ribs are formed on a rear surface of a metal plate forming said face part; and when said maximum value of said Mises stresses generated by said collision between said ball model and said club head model at said off-center positions of said front surface of said face part is not less than 1.3 times said maximum value of said Mises stress generated by said collision between said ball model and said club head model at said center of said front surface of said face part, said sectional area, said width or/and said height of said reinforcing ribs, disposed on said rear surface of said face part, which correspond to said off-center positions are set large, whereas when said ratio is less than 1.0, said sectional area, said width or/and said height of said reinforcing ribs, disposed on said rear surface of said face part, which correspond to said off-center positions are set small.  
   
   
       4 . The method according to  claim 2 , wherein said club head model is a wood club head model; said reinforcing ribs are formed on a rear surface of a metal plate forming said face part; and when said maximum value of said Mises stress generated by said collision between said ball model and said club head model at said off-center positions of said front surface of said face part is not less than 1.3 times said maximum value of said Mises stress generated by said collision between said ball model and said club head model at said center of said front surface of said face part, said sectional area, said width or/and said height of said reinforcing ribs, disposed on said rear surface of said face part, which correspond to said off-center positions are set large, whereas when said ratio is less than 1.0, said sectional area, said width or/and said height of said reinforcing ribs, disposed on said rear surface of said face part, which correspond to said off-center positions are set small.  
   
   
       5 . The golf club head designed by a designing method according to  claim 1 .  
   
   
       6 . A golf club head, wherein a central reinforcing rib is formed at a central portion of a rear surface of a face part and not less than four nor more than 10 belt-shaped reinforcing ribs are extended radially from said central reinforcing rib toward a peripheral edge of said rear surface of said face part; and 
 a maximum value of Mises stresses generated by collision between a golf ball and said golf club head at off-center positions of a front surface of said face part is set to less than 1.3 times a maximum value of a Mises stress generated by collision between said golf ball and said golf club head at a center of said front surface thereof.    
   
   
       7 . A golf club head in which a central reinforcing rib is formed at a central portion of a rear surface of a face part and not less than four nor more than 10 belt-shaped reinforcing ribs are extended radially from said central reinforcing rib toward a peripheral edge of said rear surface of said face part; a ratio (W/t) of a width W of each of said belt-shaped reinforcing ribs to a height t thereof is set to not less than 15 nor more than 40; and each of said belt-shaped reinforcing ribs forms an intersection angle of not less than 100 degrees nor more than 160 degrees with respect to a reference plane of said rear surface of said face part.  
   
   
       8 . The golf club head according to  claim 5 , wherein said reinforcing ribs are formed on a rear surface of a metal plate composing said face part; and a sectional area of said central reinforcing rib is set to not less than 20% nor more than 90% of an area of an entire rear surface of said face part.  
   
   
       9 . The golf club head according to  claim 6 , wherein said reinforcing ribs are formed on a rear surface of a metal plate composing said face part; and a sectional area of said central reinforcing rib is set to not less than 20% nor more than 90% of an area of an entire rear surface of said face part.  
   
   
       10 . The golf club head according to  claim 7 , wherein said reinforcing ribs are formed on a rear surface of a metal plate composing said face part; and a sectional area of said central reinforcing rib is set to not less than 20% nor more than 90% of an area of an entire rear surface of said face part.  
   
   
       11 . The golf club head according to  claim 8 , wherein a thickness of said central reinforcing rib is set to not less than 2.6 mm nor more than 5.0 mm; and an area of said central reinforcing rib is set to not less than 10 mm 2  nor more than 1000 mm 2 .  
   
   
       12 . The golf club head according to  claim 9 , wherein a thickness of said central reinforcing rib is set to not less than 2.6 mm nor more than 5.0 mm; and an area of said central reinforcing rib is set to not less than 10 mm 2  nor more than 1000 mm 2 .  
   
   
       13 . The golf club head according to  claim 10 , wherein a thickness of said central reinforcing rib is set to not less than 2.6 mm nor more than 5.0 mm; and an area of said central reinforcing rib is set to not less than 10 mm 2  nor more than 1000 mm 2 .  
   
   
       14 . The golf club head according to  claim 5 , wherein a portion where said adjacent belt-shaped reinforcing ribs intersect with each other is rounded; and a ratio (θ/R) of an intersection angle θ (degree) formed between said adjacent belt-shaped reinforcing ribs to a radius of curvature R (mm) of said rounded portion is set to not less than three nor more than 50.  
   
   
       15 . The golf club head according to  claim 6 , wherein a portion where said adjacent belt-shaped reinforcing ribs intersect with each other is rounded; and a ratio (θ/R) of an intersection angle θ (degree) formed between said adjacent belt-shaped reinforcing ribs to a radius of curvature R (mm) of said rounded portion is set to not less than three nor more than 50.  
   
   
       16 . The golf club head according to  claim 7 , wherein a portion where said adjacent belt-shaped reinforcing ribs intersect with each other is rounded; and a ratio (θ/R) of an intersection angle θ (degree) formed between said adjacent belt-shaped reinforcing ribs to a radius of curvature R (mm) of said rounded portion is set to not less than three nor more than 50.  
   
   
       17 . The golf club head according to  claim 8 , wherein a portion where said adjacent belt-shaped reinforcing ribs intersect with each other is rounded; and a ratio (θ/R) of an intersection angle θ (degree) formed between said adjacent belt-shaped reinforcing ribs to a radius of curvature R (mm) of said rounded portion is set to not less than three nor more than 50.  
   
   
       18 . The golf club head according to  claim 11 , wherein a portion where said adjacent belt-shaped reinforcing ribs intersect with each other is rounded; and a ratio (θ/R) of an intersection angle θ (degree) formed between said adjacent belt-shaped reinforcing ribs to a radius of curvature R (mm) of said rounded portion is set to not less than three nor more than 50.