Multi-piece solid golf ball
View Patent ↗The present invention provides a multi-piece solid golf ball having excellent flight performance and good shot feel. The present invention relates to a multi-piece solid golf ball comprising a core consisting of an inner core, an intermediate layer and an outer layer, and a cover, wherein the inner core has a flexural rigidity (R I ) of 20 to 80 MPa, a ratio (R M /R I ) of a flexural rigidity of the intermediate layer (R M ) to the (R I ) is from 0.6 to 1.4, a flexural rigidity of the outer layer is higher than the (R I ) by 70 to 500 MPa, and the intermediate layer is placed such that the a radius of the golf ball (r G ), a radius of the inner core (r I ) and a radius of a two-layer structured core obtained by forming the intermediate layer on the inner core (r T ) satisfy the following two formulae: r I /r G ≧0.70 r T /r G ≦0.83.
1. A multi-piece solid golf ball comprising a core consisting of an inner core, an intermediate layer formed on the inner core and an outer layer formed on the intermediate layer, and a cover covering the core, wherein
the inner core has a flexural rigidity of 20 to 80 MPa,
a ratio (R M /R I ) of a flexural rigidity of the intermediate layer (R M ) to that of the inner core (R I ) is within the range of 0.6 to 1.4,
a flexural rigidity of the outer layer is higher than that of the inner core by 70 to 500 MPa, and
assuming that a radius of the golf ball is represented by r g , a radius of the inner core is represented by r I and a radius of a two-layer structured core obtained by forming the intermediate layer on the inner core is represented by r T , the intermediate layer is placed such that the r G , r I and r T satisfy the following two formulae:
r I /r G ≧0.70
r T /r G ≦0.83.
2. The multi-piece solid golf ball according to claim 1 , wherein the intermediate layer has a thickness of 0.5 to 2.7 mm, and the inner core has a flexural rigidity of 30 to 80 MPa.
3. The multi-piece solid golf ball according to claim 1 , wherein the flexural rigidity of the outer layer is higher than that of the inner core by 70 to 150 MPa.
4. The multi-piece solid golf ball according to claim 1 , wherein the inner core has a flexural rigidity of 50 to 80 MPa, the intermediate layer has a thickness of 0.8 to 2.0 mm, and the outer layer has a flexural rigidity of 120 to 500 MPa.
5. The multi-piece solid golf ball according to claim 1 , wherein r G , r I and r T satisfy the following two formulae:
r I /r G ≧0.74
r T /r G ≦0.78.
6. The multi-piece solid golf ball according to claim 1 , wherein the ratio (R M /R I ) of a flexural rigidity of the intermediate layer (R M ) to that of the inner core (R I ) is within the range of 1.0 to 1.4.
7. The multi-piece solid golf ball according to claim 5 , wherein the ratio (R M /R I ) of a flexural rigidity of the intermediate layer (R M ) to that of the inner core (R I ) is within the range of 1.0 to 1.4.
8. The multi-piece solid golf ball according to claim 2 , wherein r G , r I and r T satisfy the following two formulae:
r I /r G ≧0.74
r T /r G ≦0.78.
9. The multi-piece solid golf ball according to claim 2 , wherein the ratio (R M /R I ) of a flexural rigidity of the intermediate layer (R M ) to that of the inner core (R I ) is within the range of 1.0 to 1.4.
10. The multi-piece solid golf ball according to claim 8 , wherein the ratio (R M /R I ) of a flexural rigidity of the intermediate layer (R M ) to that of the inner core (R I ) is within the range of 1.0 to 1.4.