Golf club shaft
An EI value at a point P 16 separated by 16 inches from a tip end Tp is defined as E 16 , a shaft wall thickness at the point P 16 is defined as T 16 , an EI value at a point P 6 separated by 6 inches from the tip end Tp is defined as E 6 , and a shaft wall thickness at the point P 6 is defined as T 6 . In a shaft 6 , E 16 is 2.4 (kgf·m 2 ) or more, E 6 is 2.7 (kgf·m 2 ) or less, and E 16 /E 6 is 0.95 or more but 1.50 or less, E 6 /T 6 is 1.9 or less, and E 16 /T 16 is 3.0 or more. A high-elasticity partial reinforcement layer including a fiber having a tensile elastic modulus of 30 (t/mm 2 ) or more but 40 (t/mm 2 ) or less is disposed in at least a part of a region falling within a range of ±4 inches from the point P 16.
1. A golf club shaft formed by a plurality of fiber reinforced layers, and comprising a tip end and a butt end,
wherein if an EI value at a point P 16 separated by 16 inches from the tip end is defined as E 16 (kgf·m 2 ); a shaft wall thickness at the point P 16 is defined as T 16 (mm); an EI value at a point P 6 separated by 6 inches from the tip end is defined as E 6 (kgf·m 2 ); and a shaft wall thickness at the point P 6 is defined as T 6 (mm),
E 16 is equal to or greater than 2.4 (kgf·m 2 ); E 6 is equal to or less than 2.7 (kgf·m 2 ); E 16 /E 6 is 0.95 or greater but 1.50 or less; E 6 /T 6 is equal to or less than 1.9; E 16 /T 16 is equal to or greater than 3.0; and
a high-elasticity partial reinforcement layer including a fiber having a tensile elastic modulus of 31 (t/mm 2 ) or greater but 40 (t/mm 2 ) or less is disposed in at least a part of a region falling within a range of ±1 inches from the point P 16 .
2. The golf club shaft according to claim 1 , wherein a glass partial reinforcement layer including a glass fiber is disposed in at least a part of a region falling within a range of ±4 inches from the point P 6 .
3. The golf club shaft according to claim 2 , wherein the glass partial reinforcement layer is disposed on an inner side with respect to a radial position by which the shaft wall thickness is divided into two equal parts.
4. The golf club shaft according to claim 3 , wherein the glass partial reinforcement layer is an innermost layer.
5. The golf club shaft according to claim 1 , wherein a low-elasticity partial reinforcement layer including a pitch-based carbon fiber having a tensile elastic modulus of equal to or less than 10 (t/mm 2 ) is disposed in at least a part of a region falling within a range of ±4 inches from the point P 6 .
6. The golf club shaft according to claim 5 , wherein the low-elasticity partial reinforcement layer is disposed on an outer side with respect to a radial position by which the shaft wall thickness is divided into two equal parts.
7. The golf club shaft according to claim 6 , wherein the low-elasticity partial reinforcement layer is disposed at a radial position adjacent to an outermost layer.
8. The golf club shaft according to claim 1 , wherein an axial-direction length of the high-elasticity partial reinforcement layer is 300 mm or greater but 550 mm or less.
9. The golf club shaft according to claim 2 , wherein an axial-direction length of the glass partial reinforcement layer is 50 mm or greater but 300 mm or less.
10. The golf club shaft according to claim 5 , wherein an axial-direction length of the low-elasticity partial reinforcement layer is 50 mm or greater but 300 mm or less.
11. The golf club shaft according to claim 1 , wherein the high-elasticity partial reinforcement layer is not present in a region on a butt side with respect to a point P 22 separated by 22 inches from the tip end.
12. The golf club shaft according to claim 1 , wherein the high-elasticity partial reinforcement layer is not present in a region on a butt side with respect to a point P 21 separated by 21 inches from the tip end.
13. The golf club shaft according to claim 1 , wherein the high-elasticity partial reinforcement layer is not present in a region on a butt side with respect to a point P 20 separated by 20 inches from the tip end.
14. A golf club shaft formed by a plurality of fiber reinforced layers, and comprising a tip end and a butt end,
wherein if an EI value at a point P 16 separated by 16 inches from the tip end is defined as E 16 (kgf·m 2 ); a shaft wall thickness at the point P 16 is defined as T 16 (mm); an EI value at a point P 6 separated by 6 inches from the tip end is defined as E 6 (kgf·m 2 ); and a shaft wall thickness at the point P 6 is defined as T 6 (mm),
E 16 is equal to or greater than 2.4 (kgf·m 2 ); E 6 is equal to or less than 2.7 (kgf·m 2 ); E 16 /E 6 is 0.95 or greater but 1.50 or less; E 6 /T 6 is equal to or less than 1.9; E 16 /T 16 is equal to or greater than 3.0,
a high-elasticity partial reinforcement layer including a fiber having a tensile elastic modulus of 31 (t/mm 2 ) or greater but 40 (t/mm 2 ) or less is disposed in at least a part of a region falling within a range of ±4 inches from the point P 16 ,
the high-elasticity partial reinforcement layer is not present in a region on a butt side with respect to a point P 22 separated by 22 inches from the tip end,
no high-elastic fiber-containing partial reinforcement layer is present in the region on the butt side with respect to the point P 22 separated by 22 inches from the tip end, and
the high-elastic fiber-containing partial reinforcement layer is a layer containing a fiber having a tensile elastic modulus of 30 (t/mm 2 ) or greater but 40 (t/mm 2 ) or less.
15. A golf club shaft formed by a plurality of fiber reinforced layers, and comprising a tip end and a butt end,
wherein if an EI value at a point P 16 separated by 16 inches from the tip end is defined as E 16 (kgf·m 2 ); a shaft wall thickness at the point P 16 is defined as T 16 (mm); an EI value at a point P 6 separated by 6 inches from the tip end is defined as E 6 (kgf·m 2 ); and a shaft wall thickness at the point P 6 is defined as T 6 (mm),
E 16 is equal to or greater than 2.4 (kgf·m 2 ); E 6 is equal to or less than 2.7 (kgf·m 2 ); E 16 /E 6 is 0.95 or greater but 1.50 or less; E 6 /T 6 is equal to or less than 1.9; E 16 /T 16 is equal to or greater than 3.0; and
a high-elasticity partial reinforcement layer including a fiber having a tensile elastic modulus of 30 (t/mm 2 ) or greater but 40 (t/mm 2 ) or less is disposed in at least a part of a region falling within a range of ±1 inches from the point P 16 .