GOLF CLUB HEAD
Provided is a golf club head that includes a face portion for hitting a ball. The face portion has a thick portion that includes a face center, and a peripheral portion that is thinner than the thick portion and surrounds the thick portion. The thick portion extends along a central axis line, and has a recessed portion on at least one side of the central axis line so that a central region of the thick portion along the central axis line is recessed more toward the central axis line than parts of the thick portion on two sides of the central region along the central axis line. Note that the central axis line extends in a top-sole direction or in a direction inclined from a toe side toward a heel side along a direction from a sole side toward a top side.
1 . A golf club head comprising a face portion for hitting a ball,
wherein the face portion has a thick portion that includes a face center, and a peripheral portion that is thinner than the thick portion and surrounds the thick portion,
the thick portion extends along a central axis line that extends in a top-sole direction or in a direction inclined from a toe side toward a heel side along a direction from a sole side toward a top side, and
the thick portion has a recessed portion on at least one side of the central axis line so that a central region of the thick portion along the central axis line is recessed more toward the central axis line than parts of the thick portion on two sides of the central region along the central axis line.
2 . The golf club head according to claim 1 , wherein the thick portion has the recessed portion on each side of the central axis line.
3 . The golf club head according to claim 2 , wherein the recessed portions on both sides of the central axis line oppose each other across the central axis line.
4 . The golf club head according to claim 1 ,
wherein the central axis line is a line segment having a maximum length among line segments that pass through a centroid of the thick portion and are overlapped with the thick portion, and intersects a boundary line of the thick portion at a first intersection and a second intersection,
the face portion includes a hit point distribution region, and the hit point distribution region is surrounded by a first orthogonal line that passes through the first intersection and is orthogonal to the central axis line, a second orthogonal line that passes through the second intersection and is orthogonal to the central axis line, and a boundary line of the face portion, and
a groove that extends along the boundary line of the face portion and is at least partially overlapped with the hit point distribution region is formed on a back surface side of the face portion.
5 . The golf club head according to claim 4 ,
wherein the boundary line of the face portion includes a top line on a top side that extends between a toe-side end point, being a point farthest on a toe side, and a heel-side end point, being a point farthest on a heel side, and includes a sole line on a sole side that extends between the toe-side end point and the heel-side end point,
the hit point distribution region has a first corner point on a toe side and a second corner point on a heel side on the top line, and has a third corner point on a toe side and a fourth corner point on a heel side on the sole line, and
the groove includes at least one of a toe-side groove and a heel-side groove, the toe-side groove extends at least from the first corner point into the hit point distribution region along the boundary line of the face portion but does not reach the second corner point, and the heel-side groove extends at least from the fourth corner point into the hit point distribution region along the boundary line of the face portion but does not reach the third corner point.
6 . The golf club head according to claim 5 , wherein the groove includes both the toe-side groove and the heel-side groove.
7 . The golf club head according to claim 5 , having a volume of 400 cubic centimeters or more.
8 . The golf club head according to claim 6 , having a volume of 400 cubic centimeters or more.
9 . The golf club head according to claim 4 ,
wherein the boundary line of the face portion includes a sole line on a sole side that extends between a toe-side end point, being a point farthest on a toe side, and a heel-side end point, being a point farthest on a heel side, and
the groove extends along the sole line.
10 . The golf club head according to claim 9 , having a volume less than 400 cubic centimeters.
11 . A golf club head comprising a face portion for hitting a ball,
wherein the face portion has a thick portion that includes a face center and has an approximately uniform thickness, and a peripheral portion that is thinner than the thick portion and surrounds the thick portion,
the thick portion extends along a central axis line that extends in a direction from toe-down to heel-up,
the central axis line is a line segment having a maximum length among line segments that pass through a centroid of the thick portion and are overlapped with the thick portion, and
the thick portion has a recessed portion on at least one side of the central axis line so that a central region of the thick portion along the central axis line is recessed more toward the central axis line than parts of the thick portion on two sides of the central region along the central axis line, thus approximately forming a shape as obtained by providing an ellipse whose long axis extends substantially along the central axis line with the recessed portion.
12 . The golf club head according to claim 11 , wherein the thick portion does not reach the boundary line of the face portion on both the top side and the sole side.
13 . The golf club head according to claim 11 , wherein an angle θ 1 formed by the central axis line and a horizontal direction satisfies a condition θ 1 <60°.
14 . The golf club head according to claim 12 , wherein an angle θ 1 formed by the central axis line and a horizontal direction satisfies a condition θ 1 <60°.
15 . The golf club head according to claim 11 , wherein the ellipse has a shape that is approximately line symmetrical with respect to the central axis line.
16 . The golf club head according to claim 12 , wherein the ellipse has a shape that is approximately line symmetrical with respect to the central axis line.
17 . The golf club head according to claim 13 , wherein the ellipse has a shape that is approximately line symmetrical with respect to the central axis line.
18 . The golf club head according to claim 14 , wherein the ellipse has a shape that is approximately line symmetrical with respect to the central axis line.
19 . A golf club head comprising a face portion for hitting a ball,
wherein the face portion has a thick portion that includes a face center and has an approximately uniform thickness, and a peripheral portion that is thinner than the thick portion and surrounds the thick portion,
the thick portion extends along a central axis line that extends in a top-sole direction that is a vertical direction,
the central axis line is a line segment having a maximum length among line segments that pass through a centroid of the thick portion and are overlapped with the thick portion, and
the thick portion has a recessed portion on at least one side of the central axis line so that a central region of the thick portion along the central axis line is recessed more toward the central axis line than parts of the thick portion on two sides of the central region along the central axis line, thus approximately forming a shape as obtained by providing an ellipse whose long axis extends substantially along the central axis line with the recessed portion.