JP7533129B2 - Golf Club Head - Google Patents

Description

This disclosure relates to a golf club head.

Heads are known that have a bulge on the face. The bulge is also called a horizontal face bulge. The face of a wood-type golf club head usually has a bulge.

When the ball is hit on the toe side of the sweet spot, the gear effect (horizontal gear effect) imparts a hook-spin side spin to the ball. This side spin causes the ball to deviate to the left of the target direction. However, the bulge reduces the gear effect and the ball is launched to the right of the target direction. As a result, the ball's destination can be brought closer to the target direction. When the ball is hit on the heel side of the sweet spot, the gear effect (horizontal gear effect) imparts a slicing side spin to the ball. This side spin causes the ball to deviate to the right of the target direction. However, the bulge reduces the gear effect and the ball is launched to the left of the target direction. As a result, the ball's destination can be brought closer to the target.

Note that the explanations given in this application are intended for right-handed golfers, but for left-handed golfers, these explanations should be interpreted in the opposite way.

JP 2001-95958 A discloses a golf club head in which θtx<θhx when the distance x is 20 mm or more (see Figure 4). JP 2001-17585 A discloses a golf club head in which the bulge radius of the toe-side bulge surface is 1.2 to 4 times the bulge radius of the heel-side bulge surface (see Figure 2).

JP 2001-95958 A JP 2001-17585 A

Average golfers generally suffer from mistakes such as slicing, which causes the ball to go to the right of the target. This tendency is particularly prevalent among average golfers who are weak in strength. A mistake that goes far to the right can result in an OB (out of bounds) or other trouble, resulting in a poor score. In this application, a weak golfer means a golfer with a driver head speed of 28 m/s or more and 38 m/s or less.

Golfers with little strength also suffer from a decrease in distance. By using a softer shaft, longer club length, and lighter club weight, even golfers with little strength can improve their distance.

However, it turns out that the clubs designed to help weaker golfers increase their driving distance can actually encourage mistakes that result in the ball going to the right of the target.

One of the objectives of this disclosure is to provide a golf club that can reduce mis-shots in which the ball goes far to the right of the target.

In one embodiment, the golf club has a face portion, a crown portion, and a sole portion. The face portion has a face surface with a bulge and a roll. The face surface has a point Fc which is a face center, a point Ft which is 20 mm away from the point Fc on the toe side, a point Fh which is 20 mm away from the point Fc on the heel side, a point Uc which is 15 mm away from the point Fc on the upper side, a point Ut which is 20 mm away from the point Uc on the toe side, a point Uh which is 20 mm away from the point Uc on the heel side, a point Lc which is 15 mm away from the point Fc on the lower side, a point Lt which is 20 mm away from the point Lc on the toe side, and a point Lh which is 20 mm away from the point Lc on the heel side. In a cross section along the toe-heel direction, the angle between the face normal at the point Fc and the face normal at the point Ft is θt1, and the angle between the face normal at the point Fc and the face normal at the point Fh is θh1. The angle θh1 is greater than the angle θt1. In a cross section along the toe-heel direction, the angle between the face normal at the point Uc and the face normal at the point Ut is θt2, the angle between the face normal at the point Uc and the face normal at the point Uh is θh2, the angle between the face normal at the point Lc and the face normal at the point Lt is θt3, and the angle between the face normal at the point Lc and the face normal at the point Lh is θh3. The difference (θh2-θt2) is greater than the difference (θh3-θt3).

As one aspect, a golf club can be provided that can reduce mis-shots in which the ball flies far to the right of the target.

FIG. 1 is a plan view of a golf club head according to one embodiment. FIG. 2 is a front view of the golf club head of FIG. FIG. 3 is a side view of the golf club head of FIG. 1 as viewed from the heel side. FIG. 4 is a cross-sectional view taken along the toe-heel direction of the face surface of the head in FIG. 1, the cross-sectional view being 15 mm above the face center. FIG. 5 is a cross-sectional view taken along the toe-heel direction of the face surface of the head in FIG. 1, and is a cross-sectional view taken at the face center. FIG. 6 is a cross-sectional view taken along the toe-heel direction of the face surface of the head in FIG. 1, the cross-sectional view being 15 mm below the face center. Figures 7(a), (b) and (c) are cross-sectional lines along the up-down direction of the face surface of the head in Figure 1. Figure 7(a) is a cross-sectional line 20 mm toe side of the face center. Figure 7(b) is a cross-sectional line at the face center. Figure 7(c) is a cross-sectional line 20 mm heel side of the face center. FIG. 8 is a cross-sectional line along the toe-heel direction of the face surface of the head of the comparative example, the cross-sectional line being 15 mm above the face center. FIG. 9 shows a cross-sectional line along the toe-heel direction of the face surface of the head of the comparative example, the cross-sectional line being at the face center. FIG. 10 is a cross-sectional line along the toe-heel direction of the face surface of the head of the comparative example, the cross-sectional line being 15 mm below the face center. 11(a), (b) and (c) are cross-sectional lines along the vertical direction of the face surface of the head in the comparative example. Fig. 11(a) is a cross-sectional line 20 mm toe side of the face center. Fig. 11(b) is a cross-sectional line at the face center. Fig. 11(c) is a cross-sectional line 20 mm heel side of the face center. FIG. 12 is an overall view of a golf club according to one embodiment. FIG. 13(a) is a schematic diagram showing a method for measuring the forward flex of a shaft, and FIG. 13(b) is a schematic diagram showing a method for measuring the reverse flex of a shaft. FIG. 14 is a conceptual diagram for explaining the toe-heel direction and the face-back direction.

The embodiments are described in detail below, with reference to the drawings as appropriate.

In this application, the reference state, reference vertical plane, face-back direction, toe-heel direction, up-down direction, and face-up-down direction are defined. The state in which the head 2 is placed on the horizontal plane HP with a specified lie angle and real loft angle is considered to be the reference state. As shown in FIG. 14, in this reference state, the center line Z of the hosel hole is included in a plane VP perpendicular to the horizontal plane HP. The plane VP is considered to be the reference vertical plane. The specified lie angle and real loft angle are listed in, for example, a product catalog.

In this application, the toe-heel direction is the direction of the intersection line NL between the reference vertical plane VP and the horizontal plane HP (see Figure 14).

In this application, the face-back direction is a direction perpendicular to the toe-heel direction and parallel to the horizontal plane HP.

In this application, the vertical direction is a direction perpendicular to the toe-heel direction and perpendicular to the face-back direction. In other words, in this application, the vertical direction is a direction perpendicular to the horizontal plane HP.

In this application, the face up-down direction refers to the direction of the tangent at the face center in a vertical cross section of the face surface. This vertical cross section is a cross section of a plane that includes the face center and is aligned in the up-down direction and face-back direction.

In this application, the face center is defined. The face center is determined as follows. First, an arbitrary point Pr is selected in the vertical and toe-heel directions, approximately near the center of the face surface. Next, a plane is determined that passes through this point Pr, extends along the face normal direction of the face surface at the point Pr, and is parallel to the toe-heel direction. A line of intersection between this plane and the face surface is drawn, and its midpoint Px is determined. Next, a plane is determined that passes through this midpoint Px, extends along the face normal direction of the face surface at the point Px, and is parallel to the vertical direction. A line of intersection between this plane and the face surface is drawn, and its midpoint Py is determined. Next, a plane is determined that passes through this midpoint Py, extends along the face normal direction of the face surface at the point Py, and is parallel to the toe-heel direction. A line of intersection between this plane and the face surface is drawn, and its midpoint Px is newly determined. Next, a plane is determined that passes through this new midpoint Px, extends along the face normal direction of the face surface at this point Px, and is parallel to the up-down direction. A line of intersection between this plane and the face surface is drawn, and its midpoint Py is determined anew. This process is repeated to sequentially determine Px and Py. In the repetition of this process, the new position Py (last position Py) when the distance between the new midpoint Py and the midpoint Py immediately preceding it is 0.5 mm or less for the first time is the face center.

Figure 1 is a plan view of a golf club head 2 according to one embodiment, Figure 2 is a front view of the head 2, and Figure 3 is a side view of the head 2 as seen from the heel side.

The head 2 has a face portion 4, a crown portion 6, a sole portion 8, and a hosel portion 10. The face portion 4 has a face surface 4a. The face surface 4a is the outer surface of the face portion 4. The face surface 4a is the surface that strikes the ball. The face surface 4a has a face center Fc. The hosel portion 10 has a hosel hole 12. The hosel hole 12 has a center line Z. The head 2 is hollow. The head 2 is a wood-type golf club head. The head 2 is a driver head. The volume of a typical driver head is 400 cc or more and 470 cc or less.

The face surface 4a has a sweet spot SS. The sweet spot SS is the intersection point between the face surface 4a and a straight line that is perpendicular to the face surface 4a and passes through the center of gravity of the head. The sweet spot SS is located on the heel side of the face center Fc.

The face surface 4a has a bulge. The bulge is also called a horizontal face bulge. The bulge is a roundness in a cross section along the toe-heel direction. The face surface 4a has a roll. The roll is also called a vertical face roll. The roll is a roundness in a cross section along the up-down direction. Due to the bulge and roll, the face surface 4a is a convex curved surface as a whole.

In this application, a cross section along the toe-heel direction means a cross section along the toe-heel direction and parallel to the horizontal plane HP. Also, a cross section along the up-down direction means a cross section along the up-down direction and along the face-back direction.

As shown in FIG. 2, nine points are defined on the face surface 4a. The nine points are called Fc, Ft, Fh, Uc, Ut, Uh, Lc, Lt, and Lh. These are used as names for each point and are also used as symbols for each point in the drawings. Point Fc is the face center mentioned above.

The face surface 4a has a point Ft. Point Ft is a point 20 mm away from the face center Fc toward the toe side. This "20 mm" is the distance along the toe-heel direction.

The face surface 4a has a point Fh. Point Fh is a point 20 mm away from the face center Fc toward the heel side. This "20 mm" is the distance along the toe-heel direction.

The face surface 4a has a point Uc. Point Uc is a point 15 mm above the face center Fc. This "15 mm" is the distance along the up-down direction of the face.

The face surface 4a has a point Ut. Point Ut is a point 20 mm away from point Uc on the toe side. This "20 mm" is the distance along the toe-heel direction.

The face surface 4a has a point Uh. Point Uh is a point 20 mm away from point Uc toward the heel side. This "20 mm" is the distance along the toe-heel direction.

The face surface 4a has a point Lc. Point Lc is a point 15 mm below the face center Fc. This "15 mm" is the distance along the up-down direction of the face.

The face surface 4a has a point Lt. Point Lt is a point 20 mm away from point Lc on the toe side. This "20 mm" is the distance along the toe-heel direction.

The face surface 4a has a point Lh. Point Lh is a point 20 mm away from point Lc toward the heel side. This "20 mm" is the distance along the toe-heel direction.

In a plan view of the face surface 4a, points Fc, Ft, and Fh are on a straight line L1 along the toe-heel direction. In a plan view of the face surface 4a, points Uc, Ut, and Uh are on a straight line L2 along the toe-heel direction. In a plan view of the face surface 4a, points Lc, Lt, and Lh are on a straight line L3 along the toe-heel direction. In a plan view of the face surface 4a, points Fc, Uc, and Lc are on a straight line L4 along the face up-down direction. In a plan view of the face surface 4a, points Ft, Ut, and Lt are on a straight line L5 along the face up-down direction. In a plan view of the face surface 4a, points Fh, Uh, and Lh are on a straight line L6 along the face up-down direction. The plan view is a projection onto a plane perpendicular to the normal of the face surface 4a at the face center Fc.

Figure 4 shows the cross-sectional line of the outer surface of the head in a cross section taken along line A-A in Figure 2. Figure 5 shows the cross-sectional line of the outer surface of the head in a cross section taken along line B-B in Figure 2. Figure 6 shows the cross-sectional line of the outer surface of the head in a cross section taken along line C-C in Figure 2. Only the cross-sectional lines of the face surface 4a and its surrounding area are shown in Figures 4 to 6.

As shown in Figures 4, 5 and 6, due to the above-mentioned bulge, the cross-sectional line of the face surface 4a in the toe-heel direction is a convex curve toward the outside of the head at any position in the vertical direction.

As shown in FIG. 4, point Uc has a face normal Uc1 in a cross section along the toe-heel direction. The face normal Uc1 is shown by a solid line. Point Ut has a face normal Ut1 in a cross section along the toe-heel direction. The face normal Ut1 is shown by a dashed line. Point Uh has a face normal Uh1 in a cross section along the toe-heel direction. The face normal Uh1 is shown by a dashed line.

In FIG. 4, the double-headed arrow θt2 indicates the angle between the face normal Ut1 and the face normal Uc1. In FIG. 4, the double-headed arrow θh2 indicates the angle between the face normal Uh1 and the face normal Uc1.

As shown in FIG. 5, point Fc has a face normal Fc1 in a cross section taken along the toe-heel direction. The face normal Fc1 is shown by a solid line. Point Ft has a face normal Ft1 in a cross section taken along the toe-heel direction. The face normal Ft1 is shown by a dashed line. Point Fh has a face normal Fh1 in a cross section taken along the toe-heel direction. The face normal Fh1 is shown by a dashed line.

In FIG. 5, the double-headed arrow θt1 indicates the angle between the face normal Ft1 and the face normal Fc1. In FIG. 5, the double-headed arrow θh1 indicates the angle between the face normal Fh1 and the face normal Fc1.

As shown in FIG. 6, point Lc has a face normal Lc1 in a cross section along the toe-heel direction. The face normal Lc1 is shown by a solid line. Point Lt has a face normal Lt1 in a cross section along the toe-heel direction. The face normal Lt1 is shown by a dashed line. Point Lh has a face normal Lh1 in a cross section along the toe-heel direction. The face normal Lh1 is shown by a dashed line.

In FIG. 6, the double-headed arrow θt3 indicates the angle between the face normal Lt1 and the face normal Lc1. In FIG. 6, the double-headed arrow θh3 indicates the angle between the face normal Lh1 and the face normal Lc1.

Each of the face normals described above is determined on a cross section along the toe-heel direction. The face normal at a certain point is determined based on a circle that passes through three points: that point, a point 5 mm away from that point on the toe side, and a point 5 mm away from that point on the heel side. For example, the face normal Uc1 of point Uc in FIG. 4 is determined by a circle that passes through three points: point P1 that is 5 mm away from point Uc on the toe side, point P2 that is 5 mm away from point Uc on the heel side, and point Uc. The straight line that passes through the center of this circle and point Uc is the face normal Uc1. Note that these "5 mm" are distances in the toe-heel direction. Each of the angles described above is an angle on a cross section along the toe-heel direction.

As shown in FIG. 5, the angle θh1 between the face normal Fc1 and the face normal Fh1 is greater than the angle θt1 between the face normal Fc1 and the face normal Ft1.

As shown in FIG. 4, the angle θh2 between the face normal Uc1 and the face normal Uh1 is greater than the angle θt2 between the face normal Uc1 and the face normal Ut1.

As shown in FIG. 6, the angle θh3 between the face normal Lc1 and the face normal Lh1 is greater than the angle θt3 between the face normal Lc1 and the face normal Lt1.

On face surface 4a, the difference (θh2-θt2) is greater than the difference (θh3-θt3). The difference (θh2-θt2) is greater than the difference (θh1-θt1). The difference (θh1-θt1) is greater than the difference (θh3-θt3).

Figure 7(a) shows the cross-sectional line of the outer surface of the head in a cross section taken along line D-D in Figure 2. Figure 7(b) shows the cross-sectional line of the outer surface of the head in a cross section taken along line E-E in Figure 2. Figure 7(c) shows the cross-sectional line of the outer surface of the head in a cross section taken along line F-F in Figure 2. Figures 7(a) to (c) only show the cross-sectional lines of the face surface 4a and its surrounding area.

As shown in Figures 7(a), 7(b) and 7(c), due to the above-mentioned roll, the cross-sectional line of the face surface 4a in a cross section taken along the vertical direction is a convex curve toward the outside of the head at any position in the toe-heel direction.

The face surface 4a has a bulge radius and a roll radius at each point on the face surface 4a.

Referring to FIG. 4, the face surface 4a has a bulge radius Bc2 at a point Uc. The face surface 4a has a bulge radius Bt2 at a point Ut. The face surface 4a has a bulge radius Bh2 at a point Uh. With reference to FIG. 5, the face surface 4a has a bulge radius Bc1 at a point Fc. The face surface 4a has a bulge radius Bt1 at a point Ft. The face surface 4a has a bulge radius Bh1 at a point Fh. With reference to FIG. 6, the face surface 4a has a bulge radius Bc3 at a point Lc. The face surface 4a has a bulge radius Bt3 at a point Lt. The face surface 4a has a bulge radius Bh3 at a point Lh. The symbols of these bulge radii are also used as names for each bulge radius.

The average value of bulge radius Bc2, bulge radius Bt2, and bulge radius Bh2 is defined as the upper bulge radius, also referred to as radius B2. The average value of bulge radius Bc1, bulge radius Bt1, and bulge radius Bh1 is defined as the center bulge radius, also referred to as radius B1. The average value of bulge radius Bc3, bulge radius Bt3, and bulge radius Bh3 is defined as the lower bulge radius, also referred to as radius B3.

Referring to FIG. 7(a), the face surface 4a has a roll radius Rt1 at a point Ft. The face surface 4a has a roll radius Rt2 at a point Ut. The face surface 4a has a roll radius Rt3 at a point Lt. Referring to FIG. 7(b), the face surface 4a has a roll radius Rc1 at a point Fc. The face surface 4a has a roll radius Rc2 at a point Uc. The face surface 4a has a roll radius Rc3 at a point Lc. Referring to FIG. 7(c), the face surface 4a has a roll radius Rh1 at a point Fh. The face surface 4a has a roll radius Rh2 at a point Uh. The face surface 4a has a roll radius Rh3 at a point Lh. The symbols of these roll radii are also used as names for each roll radius.

Each bulge radius is determined on a cross section along the toe-heel direction. Each roll radius is determined on a cross section along the up-down direction.

The bulge radius of a certain point is determined based on a circle that passes through three points: that point, a point 5 mm away from that point on the toe side, and a point 5 mm away from that point on the heel side. For example, the bulge radius Bc2 of point Uc in Figure 4 is the radius of a circle that passes through three points: point P1 that is 5 mm away from point Uc on the toe side, point P2 that is 5 mm away from point Uc on the heel side, and point Uc. These "5 mm" are the distances in the toe-heel direction.

The roll radius of a certain point is determined based on a circle that passes through three points: that point, a point 5 mm above that point, and a point 5 mm below that point. For example, the roll radius Rc1 of point Fc in FIG. 7(b) is the radius of a circle that passes through three points: point P3, which is 5 mm above point Fc, point P4, which is 5 mm below point Fc, and point Fc. These "5 mm" are the distances in the up-down direction of the face.

At a position 15 mm above the face center Fc, the bulge radius Bt2 is larger than the bulge radius Bc2. The bulge radius Bt2 is larger than the bulge radius Bh2. The bulge radius Bc2 is larger than the bulge radius Bh2. The face surface 4a satisfies the following relationship (a). The face surface 4a satisfies the following relationship (b).
(a) Bt2>Bh2
(b) Bt2>Bc2>Bh2

At the position of the face center Fc, the bulge radius Bt1 is larger than the bulge radius Bc1. The bulge radius Bt1 is larger than the bulge radius Bh1. The bulge radius Bc1 is larger than the bulge radius Bh1. The face surface 4a satisfies the following relationship (c). The face surface 4a satisfies the following relationship (d).
(c) Bt1>Bh1
(d) Bt1>Bc1>Bh1

At a position 15 mm below the face center Fc, the bulge radius Bt3 is greater than the bulge radius Bc3. The bulge radius Bt3 is greater than the bulge radius Bh3. The bulge radius Bc3 is greater than the bulge radius Bh3. The face surface 4a satisfies the following relationship (e). The face surface 4a satisfies the following relationship (f).
(e) Bt3>Bh3
(f) Bt3>Bc3>Bh3

The difference in bulge radius between the toe and heel on the upper side of the face surface 4a is smaller than that on the lower side of the face surface 4a. However, it is preferable that the difference in bulge radius between the toe and heel on the upper side of the face surface 4a is larger than that on the lower side of the face surface 4a. In other words, it is preferable that the difference (Bt2-Bh2) is larger than the difference (Bt3-Bh3). Example 2 described below satisfies this relationship.

At a position 20 mm away from the face center Fc to the toe side, the roll radius Rt2 is smaller than the roll radius Rt1. The roll radius Rt2 is smaller than the roll radius Rt3. The roll radius Rt1 is smaller than the roll radius Rt3. The face surface 4a satisfies the following relationship (g). The face surface 4a satisfies the following relationship (h).
(g) Rt2<Rt3
(h) Rt2<Rt1<Rt3

At the position of the face center Fc, the roll radius Rc2 is smaller than the roll radius Rc1. The roll radius Rc2 is smaller than the roll radius Rc3. The roll radius Rc1 is smaller than the roll radius Rc3. The face surface 4a satisfies the following relationship (i). The face surface 4a satisfies the following relationship (j).
(i) Rc2<Rc3
(j) Rc2<Rc1<Rc3

At a position 20 mm heel-side from the face center Fc, the roll radius Rh2 is smaller than the roll radius Rh1. The roll radius Rh2 is smaller than the roll radius Rh3. The roll radius Rh1 is smaller than the roll radius Rh3. The face surface 4a satisfies the following relationship (k). The face surface 4a satisfies the following relationship (l).
(k) Rh2<Rh3
(l) Rh2<Rh1<Rh3

Figures 8 to 10 and Figures 11(a) to (c) show the cross-sectional lines of the outer surface of the head of the comparative example. Figure 8 shows the cross-sectional line at a position 15 mm above the face center Fc, as in Figure 4. Figure 9 shows the cross-sectional line at the position of the face center Fc, as in Figure 5. Figure 10 shows the cross-sectional line at a position 15 mm below the face center Fc, as in Figure 6. Figure 11(a) shows the cross-sectional line at a position 20 mm to the toe side from the face center Fc, as in Figure 7(a). Figure 11(b) shows the cross-sectional line at the position of the face center Fc, as in Figure 7(b). Figure 11(c) shows the cross-sectional line at a position 20 mm to the heel side from the face center Fc, as in Figure 7(c).

As shown in FIG. 9, the angle θh1 between the face normal Fc1 and the face normal Fh1 is smaller than the angle θt1 between the face normal Fc1 and the face normal Ft1.

As shown in FIG. 8, the angle θh2 between the face normal Uc1 and the face normal Uh1 is smaller than the angle θt2 between the face normal Uc1 and the face normal Ut1.

As shown in FIG. 10, the angle θh3 between the face normal Lc1 and the face normal Lh1 is smaller than the angle θt3 between the face normal Lc1 and the face normal Lt1.

Referring to Figures 11(a) to (c), the roll radius Rt2 is equal to the roll radius Rt1 and the roll radius Rt3. The roll radius Rc2 is equal to the roll radius Rc1 and the roll radius Rc3. The roll radius Rh2 is equal to the roll radius Rh1 and the roll radius Rh3.

The embodiment shown in Figures 1 to 8 has the following effects:

In the head 2, the angle θh1 is greater than the angle θt1 (see FIG. 5). With this configuration, the degree to which the face normal Ft1 faces to the right can be reduced at the toe-side point Ft. Also, the degree to which the face normal Fh1 faces to the left can be increased at the heel-side point Fh. This makes it easier for the ball to fly to the left, and reduces mis-shots to the right (ball direction correction effect).

At a distance of 15 mm above the face center Fc, the angle θh2 is greater than the angle θt2 (see Figure 4). This further enhances the effect of correcting the direction of the ball as described above.

At a distance of 15 mm below the face center Fc, the angle θh3 is greater than the angle θt3 (see FIG. 6). This further enhances the effect of correcting the direction of the ball as described above.

When comparing the upper and lower sides of the face surface 4a, the difference (θh2-θt2) is greater than the difference (θh3-θt3). This configuration suppresses mis-shots in which the ball flies farther to the right than the target. When hitting the upper side of the face surface 4a, the gear effect reduces the amount of backspin and increases the flight distance. The greater the flight distance, the further to the right a mis-shot to the right will go. By making the difference (θh2-θt2) greater than the difference (θh3-θt3), balls hit on the upper side of the face surface 4a are less likely to fly to the right. For this reason, when hitting upwards, which produces greater flight distance, mis-shots that fly far to the right are effectively suppressed.

Amateur golfers are prone to mis-shots, where the ball flies to the right of the target. Especially for golfers with little power, the flight distance is short, so even if the ball flies to the right of the target, it may not reach a position where it will cause OB or trouble. However, it has been found that when hitting upwards, the flight distance is long, and even golfers with little power are likely to fly the ball to a position where it will cause OB or trouble. By making the difference (θh2-θt2) relatively large, mis-shots where the ball flies far to the right of the target are suppressed. As a result, it is possible to suppress mis-shots that cause OB or trouble, which can cause a significant loss of score. This effect is also called the right OB suppression effect. On the other hand, when hitting downwards, the flight distance is short, so it is difficult for the ball to fly far to the right. For this reason, there is little need to make the lower side of the face surface 4a more likely to fly to the left, and it is preferable to make the difference (θh3-θt3) relatively small.

In head 2, the difference (θh2-θt2) is greater than the difference (θh1-θt1). Also, the difference (θh1-θt1) is greater than the difference (θh3-θt3). These configurations also tend to make the ball fly more to the left the higher it is on the face surface 4a, which can enhance the right OB suppression effect described above.

From the viewpoint of enhancing the right OB suppression effect, the difference [(θh2-θt2)-(θh3-θt3)] is preferably 0.01° or more, more preferably 0.02° or more, and even more preferably 0.03° or more. Considering the continuity of the shape of the face surface 4a, the difference [(θh2-θt2)-(θh3-θt3)] is preferably 1.0° or less, more preferably 0.9° or less, and even more preferably 0.8° or less.

From the viewpoint of enhancing the right OB suppression effect, the ratio [(θh2-θt2)/(θh3-θt3)] is preferably 1.2 or more, more preferably 1.3 or more, and even more preferably 1.4 or more. Considering the continuity of the shape of the face surface 4a, the ratio [(θh2-θt2)/(θh3-θt3)] is preferably 5.0 or less, more preferably 4.0 or less, and even more preferably 3.0 or less.

From the viewpoint of enhancing the right OB suppression effect, the difference (θh2-θt2) is preferably 0.03° or more, more preferably 0.04° or more, more preferably 0.05° or more, more preferably 0.1° or more, and more preferably 0.2° or more. From the viewpoint of preventing excessive correction, the difference (θh2-θt2) is preferably 1.0° or less, more preferably 0.9° or less, and more preferably 0.8° or less.

From the viewpoint of making it easier for the ball to fly in the direction of the target when hit downwards, the difference (θh3-θt3) is preferably 0.5° or less, more preferably 0.4° or less, more preferably 0.3° or less, more preferably 0.2° or less, more preferably 0.1° or less, and more preferably 0.05° or less. From the viewpoint of making it easier for the ball to fly in the direction of the target when hit downwards, the difference (θh3-θt3) is preferably -0.3° or more, more preferably -0.2° or more, more preferably -0.1° or more, and more preferably -0.05° or more.

From the perspective of the effect of suppressing right OB, it is preferable that the angle θt2 at point Ut is smaller than the angle θt3 at point Lt. From the perspective of the directionality of the ball when hitting downward, it is preferable that the angle θh3 at point Lh is smaller than the angle θh2 at point Uh.

From the viewpoint of the effect of correcting the direction of the hit ball, the angle θt1 is preferably 5.5° or less, more preferably 4.5° or less, more preferably 3.5° or less, more preferably 3.2° or less, and more preferably 3.0° or less. From the viewpoint of preventing excessive correction, the angle θt1 is preferably 1.0° or more, more preferably 1.5° or more, and more preferably 2.0° or more.

From the viewpoint of the effect of correcting the direction of the hit ball, the angle θh1 is preferably 1.0° or more, more preferably 1.5° or more, and more preferably 2.0° or more. From the viewpoint of preventing excessive correction, the angle θh1 is preferably 5.5° or less, more preferably 4.5° or less, and more preferably 3.5° or less.

From the viewpoint of the effect of correcting the direction of the ball and the effect of suppressing right OB, the angle θt2 is preferably 5.5° or less, more preferably 4.5° or less, more preferably 3.5° or less, more preferably 3.2° or less, and more preferably 3.0° or less. From the viewpoint of preventing excessive correction, the angle θt2 is preferably 1.0° or more, more preferably 1.5° or more, and more preferably 2.0° or more.

From the viewpoint of the effect of correcting the direction of the hit ball, the angle θh2 is preferably 1.0° or more, more preferably 1.5° or more, and more preferably 2.0° or more. From the viewpoint of preventing excessive correction, the angle θh2 is preferably 5.5° or less, more preferably 4.5° or less, and more preferably 3.5° or less.

From the viewpoint of the effect of correcting the direction of the hit ball, the angle θt3 is preferably 5.5° or less, more preferably 4.5° or less, more preferably 3.5° or less, more preferably 3.2° or less, and more preferably 3.0° or less. From the viewpoint of preventing excessive correction, the angle θt3 is preferably 1.0° or more, more preferably 1.5° or more, and more preferably 2.0° or more.

From the viewpoint of the effect of correcting the direction of the hit ball, the angle θh3 is preferably 1.0° or more, more preferably 1.5° or more, and more preferably 2.0° or more. From the viewpoint of preventing excessive correction, the angle θh3 is preferably 5.5° or less, more preferably 4.5° or less, and more preferably 3.5° or less.

Regarding the bulge radius, in the head 2, the following relationship (c) is established at the position of the face center Fc.
(c) Bt1>Bh1
By increasing the radius of curvature of the bulge on the toe side, it is possible to reduce the degree to which the face normal on the toe side points to the right. Also, by decreasing the radius of curvature of the bulge on the heel side, it is possible to increase the degree to which the face normal on the heel side points to the left. As a result, the ball is more likely to fly to the left on the toe and heel sides, and mis-shots to the right are suppressed. In other words, the effect of correcting the ball direction is enhanced. This effect can be further enhanced by the following relationship (d).
(d) Bt1>Bc1>Bh1

At a position 15 mm above the face center Fc, the following relationships (a) and (b) are established. These configurations can further improve the effect of correcting the direction of the ball.
(a) Bt2>Bh2
(b) Bt2>Bc2>Bh2

At a position 15 mm below the face center Fc, the following relationships (e) and (f) are established. These configurations can further improve the effect of correcting the direction of the ball.
(e) Bt3>Bh3
(f) Bt3>Bc3>Bh3

From the viewpoint of the effect of correcting the direction of the ball, the bulge radius Bt1 of point Ft is preferably 12 inches or more, more preferably 14 inches or more, and more preferably 16 inches or more. From the viewpoint of preventing excessive correction, the bulge radius Bt1 of point Ft is preferably 22 inches or less, more preferably 21 inches or less, and more preferably 20 inches or less.

From the viewpoint of the effect of correcting the direction of the ball, the bulge radius Bh1 of point Fh is preferably 17 inches or less, more preferably 16 inches or less, and more preferably 15 inches or less. From the viewpoint of preventing excessive correction, the bulge radius Bh1 of point Fh is preferably 8 inches or more, more preferably 10 inches or more, and more preferably 12 inches or more.

From the viewpoint of forming a bulge on the entire face surface 4a, it is preferable that the bulge radius at point Fc is between the bulge radius at point Fh and the bulge radius at point Ft. From this viewpoint, the bulge radius Bc1 at point Fc is preferably 10 inches or more, more preferably 12 inches or more, and more preferably 14 inches or more. From this viewpoint, the bulge radius Bc1 at point Fc is preferably 18 inches or less, more preferably 17 inches or less, and more preferably 16 inches or less.

From the viewpoint of the effect of correcting the direction of the ball, the bulge radius Bt2 of point Ut is preferably 12 inches or more, more preferably 14 inches or more, and more preferably 16 inches or more. From the viewpoint of preventing excessive correction, the bulge radius Bt2 of point Ut is preferably 22 inches or less, more preferably 21 inches or less, and more preferably 20 inches or less.

From the viewpoint of the effect of correcting the direction of the ball, the bulge radius Bh2 of point Uh is preferably 17 inches or less, more preferably 16 inches or less, and more preferably 15 inches or less. From the viewpoint of preventing excessive correction, the bulge radius Bh2 of point Uh is preferably 8 inches or more, more preferably 10 inches or more, and more preferably 12 inches or more.

The bulge radius at point Uc is preferably between the bulge radius at point Uh and the bulge radius at point Ut. From this viewpoint, the bulge radius Bc2 at point Uc is preferably 10 inches or more, more preferably 12 inches or more, and more preferably 14 inches or more. From this viewpoint, the bulge radius Bc2 at point Uc is preferably 18 inches or less, more preferably 17 inches or less, and more preferably 16 inches or less.

From the viewpoint of the effect of correcting the direction of the ball, the bulge radius Bt3 of point Lt is preferably 12 inches or more, more preferably 14 inches or more, and more preferably 16 inches or more. From the viewpoint of preventing excessive correction, the bulge radius Bt3 of point Lt is preferably 22 inches or less, more preferably 21 inches or less, and more preferably 20 inches or less.

From the viewpoint of the effect of correcting the direction of the ball, the bulge radius Bh3 of point Lh is preferably 17 inches or less, more preferably 16 inches or less, and more preferably 15 inches or less. From the viewpoint of preventing excessive correction, the bulge radius Bh3 of point Lh is preferably 8 inches or more, more preferably 10 inches or more, and more preferably 12 inches or more.

From the viewpoint of forming a bulge on the entire face surface 4a, the bulge radius at point Lc is preferably between the bulge radius at point Lh and the bulge radius at point Lt. From this viewpoint, the bulge radius Bc3 at point Lc is preferably 10 inches or more, more preferably 12 inches or more, and more preferably 14 inches or more. From this viewpoint, the bulge radius Bc3 at point Lc is preferably 18 inches or less, more preferably 17 inches or less, and more preferably 16 inches or less.

The difference in bulge radius between the toe and heel on the upper side of the face surface 4a is preferably larger than that on the lower side of the face surface 4a. In other words, the difference (Bt2-Bh2) is preferably larger than the difference (Bt3-Bh3). This configuration can suppress the left-right variation in the landing point of the ball. When hitting upwards, the gear effect reduces the amount of backspin and increases the flight distance. The longer the flight distance, the further to the right a mis-shot to the right will go. By making the difference (Bt2-Bh2) larger than the difference (Bt3-Bh3), mis-shots to the right are effectively suppressed in upward hits that have a larger flight distance. As a result, mis-shots that fly far to the right are suppressed. In other words, the effect of suppressing right OB described above is further enhanced.

When hitting downwards (hitting below the face center Fc), the vertical gear effect increases backspin, but sidespin also tends to increase. The head rotation caused by hitting downwards is not completely vertical. Also, when hitting downwards, if the impact point shifts to the toe or heel side, a horizontal gear effect occurs. Due to these factors, an increase in spin caused by hitting downwards is accompanied by an increase in sidespin. Similarly, a decrease in spin caused by hitting upwards (hitting above the face center Fc) is accompanied by a decrease in sidespin. A downward hit is a hit below the face center Fc, and an upward hit is a hit above the face center Fc.

The upper bulge radius B2 is preferably larger than the lower bulge radius B3. By increasing the upper bulge radius B2, it is possible to effectively suppress mis-shots that fly far to the right when hit on the toe side in upward hits that produce greater distances. Also, it is possible to suppress shots that fly excessively to the left when hit on the heel side in upward hits that produce greater distances. On the other hand, in downward hits, since the distance is relatively short, mis-shots that fly far to the right are unlikely to occur. In downward hits, by decreasing the lower bulge radius B3, it is possible to make the ball more likely to return toward the target by side spin. By suppressing mis-shots that fly far to the right when hit on the toe side in upward hits, suppressing shots that fly too far to the left when hit on the heel side in upward hits, and making it easier for the ball to fly toward the target when hit downward, it is possible to suppress the left-right variation in the landing point of the ball (left-right variation suppression effect).

From the viewpoint of continuity of the face surface 4a, it is preferable that the center bulge radius B1 is smaller than the upper bulge radius B2, and it is preferable that the center bulge radius B1 is larger than the lower bulge radius B3.

From the viewpoint of suppressing left-right variation, the difference (B2-B3) is preferably 0.1° or more, more preferably 0.3° or more, more preferably 0.5° or more, and more preferably 0.7° or more. From the viewpoint of preventing excessive correction, the difference (B2-B3) is preferably 3.0° or less, more preferably 2.5° or less, and more preferably 2.0° or less.

From the viewpoint of suppressing left-right variation, the upper bulge radius B2 is preferably 14.0° or more, more preferably 14.5° or more, and more preferably 15.0° or more. From the viewpoint of preventing excessive correction, the upper bulge radius B2 is preferably 21.0° or less, more preferably 20.0° or less, and more preferably 19.0° or less.

Regarding the roll radius, in the head 2, the following relationship (i) holds at the position of the face center Fc.
(i) Rc2<Rc3

By reducing the radius of curvature of the roll on the upper side of the face surface 4a, the face normal can be directed upward. By increasing the radius of curvature of the roll on the lower side of the face surface 4a, the face normal can be directed upward. As a result, the launch angle of the ball can be increased for upward and downward hits (launch angle correction effect). For golfers with little power, a high launch angle can provide a stable flight distance. For golfers with little power, the trajectory is low and the flight distance is likely to decrease, especially for downward hits (hits on the lower side of the face surface 4a). However, by increasing the radius of curvature of the roll on the lower side of the face surface 4a, a stable flight distance can be obtained even for downward hits.

Furthermore, at the position of the face center Fc, the following relationship (j) is established: This configuration can further enhance the effect of correcting the launch angle.
(j) Rc2<Rc1<Rc3

At a position 20 mm to the toe side from the face center Fc, the following relationships (g) and (h) are established. With these configurations, the effect of correcting the launch angle can be further improved.
(g) Rt2<Rt3
(h) Rt2<Rt1<Rt3

At a position 20 mm toward the heel side from the face center Fc, the following relationships (k) and (l) are established. These configurations can further enhance the effect of correcting the launch angle.
(k) Rh2<Rh3
(l) Rh2<Rh1<Rh3

Figure 12 shows a golf club 20 of one embodiment. The golf club 20 has the head 2 described above, a shaft 22, and a grip 24. The head 2 is attached to the tip portion of the shaft 22. The grip 24 is attached to the butt portion of the shaft 22.

In FIG. 12, the double-headed arrow E1 indicates the club length. By increasing the club length E1, the shaft can bend, improving the catch. From the viewpoint of increasing the flight distance while suppressing mis-shots to the right for weak golfers, the club length E1 is preferably 45.75 inches or more, more preferably 46.0 inches or more, and more preferably 46.25 inches or more. From the viewpoint of making the club swingable by weak golfers, the club length E1 is preferably 48.0 inches or less, more preferably 47.5 inches or less, more preferably 47.0 inches or less, more preferably 46.75 inches or less, and more preferably 46.5 inches or less. The club length E1 is measured in accordance with the regulations of the Royal and Ancient Golf Club of Saint Andrews (R&A). This rule is found in the latest Golf Rules published by the R&A, in Appendix II: Club Design, section 1: Length. This measurement method is also called the 60-degree measurement method, because the club is placed on a horizontal plane and the sole is placed on a surface that is at a 60-degree angle to the horizontal plane.

Note that catch refers to the degree to which the face does not open at impact. Good catch reduces mis-shots to the right and improves flight distance. A mis-shot to the right is one in which the ball flies to the right of the target.

From the viewpoint of making the club easy for weak golfers to swing, the club weight is preferably 280g or less, more preferably 275g or less, more preferably 270g or less, and more preferably 265g or less. From the viewpoint of the strength of the shaft and head, the club weight is preferably 240g or more, more preferably 245g or more, and more preferably 250g or more.

From the viewpoint of making the club easy for weak golfers to swing, the head weight is preferably 192g or less, more preferably 191g or less, and even more preferably 190g or less. From the viewpoint of resilience performance, the head weight is preferably 183g or more, more preferably 184g or more, and even more preferably 185g or more.

From the perspective of preventing poorly-strengthened golfers from making mis-shots to the right, it is preferable for the face angle to be on the hook side. In other words, in the above-mentioned reference state, it is preferable for the face normal Fc1 of the face center Fc to be pointing to the left (hook side) of the straight line that passes through the face center Fc and runs along the face-back direction. As mentioned above, this explanation is for right-handed golfers, and the left and right are reversed for left-handed golfers.

The sweet spot SS is preferably located on the heel side of the face center Fc. By positioning the head's center of gravity on the heel side, the moment of inertia of the head around the center line Z of the hosel hole is reduced, making it difficult for the face surface to open on impact. This helps to prevent mis-shots to the right.

It is preferable that the reverse flex of the shaft is large. By making the reverse flex softer, the head is easier to return and the catch can be improved. From this viewpoint, the reverse flex of the shaft is preferably 140 mm or more, more preferably 145 mm or more, and more preferably 150 mm or more. From the viewpoint of ease of swinging, the reverse flex of the shaft is preferably 190 mm or less, more preferably 180 mm or less, and more preferably 170 mm or less.

When the club is long and the shaft is flexible, the head speed increases and the flight distance can be improved. However, in this case, it has been found that the toe down becomes large and the face is easily opened. In this disclosure, the specifications of the face surface 4a can suppress this face opening. As a result, weak golfers can increase the head speed while suppressing mis-shots to the right. From this perspective, the total of the forward flex and the reverse flex is preferably 300 mm or more, more preferably 310 mm or more, and more preferably 320 mm or more. From the perspective of ease of swinging, the total of the forward flex and the reverse flex is preferably 400 mm or less, more preferably 390 mm or less, and more preferably 380 mm or less.

Figure 13(a) is a schematic diagram showing a method for measuring forward flex. In this measurement, a first support point S1 is set at a position 1093 mm from the tip end Tp. Furthermore, a second support point S2 is set at a position 953 mm from the tip end Tp. A support R1 that supports the shaft 22 from above is provided at the first support point S1. A support R2 that supports the shaft 22 from below is provided at the second support point S2. In a no-load state, the shaft axis of the shaft 22 is horizontal. A load of 2.7 kgf is applied vertically downward to a load point m1 located 129 mm away from the tip end Tp. The distance (mm) of the load point m1 between the no-load state and the stable state with a load applied is the forward flex. This distance is measured along the vertical direction.

The cross-sectional shape of the part of the support R1 that abuts against the shaft (hereinafter referred to as the abutment part) is as follows: In a cross section parallel to the shaft axial direction, the cross-sectional shape of the abutment part of the support R1 has a convex roundness. The radius of curvature of this roundness is 15 mm. In a cross section perpendicular to the shaft axial direction, the cross-sectional shape of the abutment part of the support R1 has a concave roundness. The radius of curvature of this concave roundness is 40 mm. In a cross section perpendicular to the shaft axial direction, the horizontal length (depth direction length in FIG. 13(a)) of the abutment part of the support R1 is 15 mm. The cross-sectional shape of the abutment part of the support R2 is the same as that of the support R1. The cross-sectional shape of the abutment part of the load indenter (not shown) that applies a load of 2.7 kgf at the load point m1 has a convex roundness in a cross section parallel to the shaft axial direction. The radius of curvature of this roundness is 10 mm. The cross-sectional shape of the contact portion of the load indenter (not shown) that applies a load of 2.7 kgf at the load point m1 is a straight line in a cross section perpendicular to the shaft axial direction. The length of this straight line is 18 mm. A weight including this load indenter is hung from the load point m1.

Figure 13(b) shows the method for measuring the reverse flex. The reverse flex is measured in the same manner as the forward flex, except that the first support point S1 is set to a point 12 mm away from the tip end Tp, the second support point S2 is set to a point 152 mm away from the tip end Tp, the load point m2 is set to a point 924 mm away from the tip end Tp, and the load is set to 1.3 kgf.

In particular, if the shaft is flexible, the toe-down becomes large and the face is more likely to turn to the right at impact. From the viewpoint of suppressing the effect of this toe-down, the lie angle of the club is preferably 59 degrees or more, more preferably 59.5 degrees or more, and even more preferably 60 degrees or more. If the lie angle is too large, it is difficult to address the ball. From this viewpoint, the lie angle is preferably 64 degrees or less, more preferably 63 degrees or less, and even more preferably 62 degrees or less. The lie angle is the angle between the center line Z and the horizontal plane HP in the reference state.

From the viewpoint of suppressing miss shots to the right and increasing the directional stability of the ball, the lateral moment of inertia of the head is preferably 4000 (g·cm ² ) or more, more preferably 4100 (g·cm ² ) or more, and even more preferably 4200 (g·cm ² ) or more. Considering the head volume restrictions in the rules, the lateral moment of inertia of the head is preferably 5500 (g·cm ² ) or less, more preferably 5400 (g·cm ² ) or less, and even more preferably 5300 (g·cm ² ) or less. The lateral moment of inertia of the head is the moment of inertia about a straight line passing through the center of gravity of the head along the up-down direction. This moment of inertia can be measured, for example, using MODEL NUMBER RK/005-002 manufactured by INERTIA DYNAMICS.

The effects of the present disclosure will be demonstrated in the following examples, but the present disclosure should not be interpreted in a restrictive manner based on the description of these examples.

[Example 1]
A forged face member and a cast body member were welded together to obtain a driver head made of a titanium alloy. The specifications of the face surface of the head were the same as those of the face surface 4a described above. The head weight was 184 g. A shaft was obtained by a sheet winding method using a plurality of prepreg sheets. A grip was obtained by heating and pressurizing a rubber composition in a mold. The head and grip were attached to the shaft to obtain a golf club shown in FIG. 12. This golf club had a club length of 47 inches, a club weight of 255 g, a lie angle of 60 degrees, a shaft reverse flex of 150 mm, and a shaft forward flex of 170 mm. The specifications of the head of Example 1 are shown in Tables 1 to 3 below.

[Example 2]
The shape of the face was changed by polishing to the specifications shown in Tables 1 to 3, but the rest was the same as in Example 1, to obtain a head and a golf club of Example 2.

[Comparative Example]
A head and a golf club of a comparative example were obtained in the same manner as in Example 1, except that the shape of the face surface was changed by polishing to the specifications shown in Tables 1 to 3. The head of the comparative example has the same face surface 4b as described above.

Five golfers with a driver head speed of 28 m/s to 38 m/s and who often miss shots to the right conducted the actual hitting test. Each tester hit five balls with each club, and 25 pieces of hitting data were obtained for each club. Of these 25 shots, the number of shots in which the final landing point of the ball was 20 yards or more to the right of the target direction was 3 in Example 1, 2 in Example 2, and 7 in the Comparative Example. In addition, the left-right deviation width of the hit ball was 14 yards in Example 1, 11 yards in Example 2, and 21 yards in the Comparative Example. The left-right deviation width is the average deviation width from the target direction. Whether the ball deviated to the right or left, this deviation width was considered to be a positive value.

As such, the examples are rated higher than the comparative examples.

The following notes are part of the invention contained in this disclosure.
[Appendix 1]
The golf club has a face portion, a crown portion, and a sole portion,
The face portion has a face surface having a bulge and a roll,
The face surface is
a point Fc which is a face center, a point Ft which is 20 mm away from said point Fc on the toe side, and a point Fh which is 20 mm away from said point Fc on the heel side;
A point Uc is 15 mm above the point Fc, a point Ut is 20 mm to the toe side from the point Uc, and a point Uh is 20 mm to the heel side from the point Uc.
A point Lc is 15 mm below the point Fc, a point Lt is 20 mm to the toe side from the point Lc, and a point Lh is 20 mm to the heel side from the point Lc.
It has
In a cross section along the toe-heel direction, when an angle between a face normal at the point Fc and a face normal at the point Ft is θt1, and an angle between the face normal at the point Fc and a face normal at the point Fh is θh1, the angle θh1 is greater than the angle θt1,
In a cross section along the toe-heel direction, when the angle between the face normal at the point Uc and the face normal at the point Ut is θt2, the angle between the face normal at the point Uc and the face normal at the point Uh is θh2, the angle between the face normal at the point Lc and the face normal at the point Lt is θt3, and the angle between the face normal at the point Lc and the face normal at the point Lh is θh3,
A golf club head in which the difference (θh2-θt2) is greater than the difference (θh3-θt3).
[Appendix 2]
2. The golf club head according to claim 1, wherein the ratio [(θh2-θt2)/(θh3-θt3)] is 1.2 or more.
[Appendix 3]
a bulge radius Bt1 at the point Ft is larger than a bulge radius Bc1 at the point Fc,
3. The golf club head according to claim 1, wherein the bulge radius Bc1 at the point Fc is greater than the bulge radius Bh1 at the point Fh.
[Appendix 4]
A golf club head as described in any one of Appendices 1 to 3, wherein when the bulge radius at the point Ut is Bt2, the bulge radius at the point Uh is Bh2, the bulge radius at the point Lt is Bt3, and the bulge radius at the point Lh is Bh3, the difference (Bt2-Bh2) is greater than the difference (Bt3-Bh3).
[Appendix 5]
5. The golf club head according to claim 1, wherein the roll radius at the point Uc is smaller than the roll radius at the point Lc.
[Appendix 6]
A golf club comprising a head, a shaft, and a grip according to any one of claims 1 to 5,
The club weight is 280g or less,
The club length is 45.75 inches or more.
The shaft has a reverse flex of 140 mm or more;
A golf club with a lie angle of 59 degrees or more.

2...Golf club head 4...Face portion 4a...Face surface 6...Crown portion 8...Sole portion 10...Hosel portion 20...Golf club 22...Shaft 24...Grip SS...Sweet spot Fc...Face center Ft...Point 20mm away from point Fc on the toe side Fh...Point 20mm away from point Fc on the heel side Uc...Point 15mm away from point Fc on the upper side Ut...Point 20mm away from point Uc on the toe side Uh...Point 20mm away from point Uc on the heel side Lc...Point 15mm away from point Fc on the lower side Lt...Point 20mm away from point Lc on the toe side Lh...Point 20mm away from point Lc on the heel side

Claims (6)

The golf club has a face portion, a crown portion, and a sole portion,
The face portion has a face surface having a bulge and a roll,
The face surface is
a point Fc which is a face center, a point Ft which is 20 mm away from said point Fc on the toe side, and a point Fh which is 20 mm away from said point Fc on the heel side;
A point Uc is 15 mm above the point Fc, a point Ut is 20 mm to the toe side from the point Uc, and a point Uh is 20 mm to the heel side from the point Uc.
A point Lc is 15 mm below the point Fc, a point Lt is 20 mm to the toe side from the point Lc, and a point Lh is 20 mm to the heel side from the point Lc.
It has
In a cross section along the toe-heel direction, when an angle between a face normal at the point Fc and a face normal at the point Ft is θt1, and an angle between the face normal at the point Fc and a face normal at the point Fh is θh1, the angle θh1 is greater than the angle θt1,
In a cross section along the toe-heel direction, when the angle between the face normal at the point Uc and the face normal at the point Ut is θt2, the angle between the face normal at the point Uc and the face normal at the point Uh is θh2, the angle between the face normal at the point Lc and the face normal at the point Lt is θt3, and the angle between the face normal at the point Lc and the face normal at the point Lh is θh3,
A golf club head in which the difference (θh2-θt2) is greater than the difference (θh3-θt3). The golf club head according to claim 1, in which the ratio [(θh2-θt2)/(θh3-θt3)] is 1.2 or greater. a bulge radius Bt1 at the point Ft is larger than a bulge radius Bc1 at the point Fc,
3. The golf club head according to claim 1, wherein the bulge radius Bc1 at the point Fc is greater than the bulge radius Bh1 at the point Fh. A golf club head according to any one of claims 1 to 3, in which when the bulge radius at point Ut is Bt2, the bulge radius at point Uh is Bh2, the bulge radius at point Lt is Bt3, and the bulge radius at point Lh is Bh3, the difference (Bt2-Bh2) is greater than the difference (Bt3-Bh3). A golf club head according to any one of claims 1 to 4, in which the roll radius at point Uc is smaller than the roll radius at point Lc. A golf club comprising the head, shaft, and grip according to any one of claims 1 to 5,
The club weight is 280g or less,
The club length is 45.75 inches or more.
The shaft has a reverse flex of 140 mm or more;
A golf club with a lie angle of 59 degrees or more.

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