Golf club head

Abstract

To provide a golf club head including a weight part of a new structure exhibiting new effect.SOLUTION: A head 100 includes a face part 104, a sole part 108, and an inner weight part 120 disposed in an inner surface 108b of the sole part 108, and positioned separately from the face part 104. The inner weight part 120 includes a base part 122, and a projection part 124 projecting from the base part 122 to a face side while being separated from the inner surface 108b of the sole part 108. The projection part 124 is positioned at the face side from a head gravity center CG. In the projection part 124, a thickness at least one of the toe side portion and the heel side portion is larger than that of the central portion, or in the projection part 124, the central portion in a toe-heel direction is missing. The inner weight part 120 may be integrally molded with the sole part 108, or may be a different member from the sole part 108.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present disclosure relates to a golf club head.

Background Art

[0002] From the viewpoint of a low center of gravity, a golf club head having a weight portion provided on the inner surface of the sole portion has been proposed. Japanese Patent No. 6645569 discloses a hollow golf club head having a weight portion provided along the leading edge on the inner surface of the sole portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The inventor has found that a new effect can be obtained by a novel structure related to the weight portion provided on the inner surface of the sole portion.

[0005] The present disclosure provides a golf club head having a weight portion with a new structure that exhibits a new effect.

Means for Solving the Problems

[0006] In one aspect, a golf club head includes a face portion, a sole portion, and an internal weight portion provided on the inner surface of the sole portion and spaced apart from the face portion. The internal weight portion includes a base portion and a protruding portion that protrudes from the base portion toward the face side while being spaced apart from the inner surface of the sole portion. The protruding portion is located on the face side of the head center of gravity. At least one of the toe-side portion and the heel-side portion of the protruding portion has a thickness greater than the thickness of the central portion thereof, or the central portion in the toe-heel direction is missing.

Effects of the Invention

[0007] On one side, a golf club head having a weight portion with a new structure that exhibits a new effect can be provided.

Brief Description of the Drawings

[0008]

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Embodiments for Carrying Out the Invention

[0009] Hereinafter, the embodiments will be described in detail while appropriately referring to the drawings.

[0010] In the present application, a reference state, a reference vertical plane, a toe-heel direction, a face-back direction, a vertical direction, and a face center are defined.

[0011] A state where the head is placed on the ground plane GP at a predetermined lie angle is defined as the reference state. As shown in FIG. 30, in this reference state, the shaft axis Z is included in a plane VP perpendicular to the ground plane GP. The shaft axis Z is the center line of the shaft when the shaft is attached to the head. Usually, the shaft axis Z is the center line of the hosel hole. The plane VP is defined as the reference vertical plane. The predetermined lie angle is, for example, published in a product catalog.

[0012] In this reference state, the orientation of the striking face is determined such that the normal line of the striking face at the face center is included in a plane perpendicular to the reference vertical plane VP and perpendicular to the ground plane GP. That is, in a plan view seen from above, the normal line of the striking face at the face center is perpendicular to the reference vertical plane VP.

[0013] In the present application, the toe-heel direction is the direction of the intersection line NL between the reference vertical plane VP and the ground plane GP (see FIG. 30).

[0014] In the present application, the face-back direction is a direction perpendicular to the toe-heel direction and parallel to the ground plane GP.

[0015] In the present application, the vertical direction is a direction perpendicular to the toe-heel direction and perpendicular to the face-back direction. In other words, in the present application, the vertical direction is a direction perpendicular to the ground plane GP.

[0016] In the present application, the face center Fc is determined as follows. First, in the vertical direction and the toe-heel direction, an arbitrary point Pr near the approximate center of the striking face is selected. Next, a plane is determined that passes through this point Pr and extends along the normal direction of the striking face at this point Pr and is parallel to the toe-heel direction. An intersection line between this plane and the striking face is drawn, and the midpoint Px thereof is determined. Next, a plane is determined that passes through this midpoint Px and extends along the normal direction of the striking face at this point Px and is parallel to the vertical direction. An intersection line between this plane and the striking face is drawn, and the midpoint Py thereof is determined. Next, a plane is determined that passes through this midpoint Py and extends along the normal direction of the striking face at this point Py and is parallel to the toe-heel direction. An intersection line between this plane and the striking face is drawn, and the midpoint Px is newly determined. Next, a plane is determined that passes through this new midpoint Px and extends along the normal direction of the striking face at this point Px and is parallel to the vertical direction. An intersection line between this plane and the striking face is drawn, and the midpoint Py is newly determined. This process is repeated, and Px and Py are sequentially determined. During the repetition of this process, the position Py (the last position Py) when the distance between the new midpoint Py and the immediately preceding midpoint Py first becomes 0.5 mm or less is the face center Fc.

[0017] [First Embodiment] FIG. 1 is a plan view of the golf club head 100 according to the first embodiment, FIG. 2 is a perspective view of the head 100, FIG. 3 is a perspective view of the body member 100b of the head 100, and FIG. 4 is a front view of the body member 100b. FIG. 5 shows the body member 100b and is a view with a slightly lower viewpoint than FIG. 4. FIG. 6(a) is a cross-sectional view taken along line A-A of FIG. 1. FIG. 6(b) is a cross-sectional view taken along line B-B of FIG. 1. The center of gravity of the head exists at the position of line B-B. FIG. 6(c) is a cross-sectional view taken along line C-C of FIG. 1.

[0018] Figures 6(a), 6(b) and 6(c) are cross-sectional views along the face-back direction. The cross-sectional view along the face-back direction is also referred to as the longitudinal cross-sectional view in the present application. In the reference state, the longitudinal cross-sectional view is a cross-sectional view along a plane parallel to the face-back direction and perpendicular to the ground plane GP.

[0019] The head 100 has a face portion 104, a crown portion 106, a sole portion 108 and a hosel portion 110. The sole portion 108 has an outer surface 108a and an inner surface 108b. The hosel portion 110 has an exposed portion 110a exposed to the outside and an inner extending portion 110b located inside the head 100. Further, the hosel portion 110 has a hosel hole 112. The hosel hole 112 opens at the upper end of the exposed portion 110a and continuously extends from the exposed portion 110a to the inner extending portion 110b. The face portion 104 has a striking face 104a. The striking face 104a is the outer surface of the face portion 104. The head 100 may have a skirt portion (side portion) extending between the crown portion 106 and the sole portion 108. Note that the striking face is also simply referred to as the face.

[0020] The head 100 is a hollow head. The head 100 is a wood-type head. The head 100 is a fairway wood-type head. The head 100 may be a hybrid-type head. The head 100 may be a driver head.

[0021] From the perspective of components, the head 100 has a face member 100a and a body member 100b. The face member 100a is welded to the body member 100b. In the head 100 that has been subjected to finish polishing and painting, the boundary between the face member 100a and the body member 100b is not visible. In FIGS. 6(a), 6(b) and 6(c), the boundary k1 between the face member 100a and the body member 100b is shown.

[0022] In the cross-sectional views of FIGS. 6(a), 6(b), and 6(c), the portion on the face side of the boundary k1 is the face member 100a. The face member 100a has a cup-shaped configuration as a whole. Such a face member 100a is also referred to as a cup face. The face member 100a includes the entire face portion 104, a part of the crown portion 106, and a part of the sole portion 108. The face member 100a has a main portion that forms the face portion 104 and a rear extending portion that extends rearward from the periphery of the main portion. The outer surface of this main portion is the face portion 104, and this rear extending portion constitutes a part of the crown portion 106 and a part of the sole portion 108.

[0023] The material of the face member 100a is metal. Examples of this metal include stainless steel, maraging steel, titanium alloy, aluminum alloy, and magnesium alloy. Part or all of the face member 100a may be formed of a non-metal. For example, part or all of the face member 100a may be formed of a carbon fiber reinforced resin.

[0024] The material of the body member 100b is metal. Examples of this metal include stainless steel, maraging steel, titanium alloy, aluminum alloy, and magnesium alloy. Part or all of the body member 100b may be formed of a non-metal. For example, part or all of the body member 100b may be formed of a carbon fiber reinforced resin.

[0025] FIG. 7 is an enlarged view of FIG. 6(b). FIG. 8 is an enlarged view showing a part of FIG. 7.

[0026] The head 100 has an internal weight portion 120. The body member 100b has the internal weight portion 120. The internal weight portion 120 is provided inside the sole portion 108. The internal weight portion 120 is provided on the inner surface 108b of the sole portion 108.

[0027] The internal weight portion 120 is integral with the sole portion 108. The internal weight portion 120 is integrally formed with the sole portion 108. The internal weight portion 120 is integral with the body member 100b. The entire body member 100b including the internal weight portion 120 is integrally formed. The forming method of the body member 100b is casting. The body member 100b is formed by lost-wax precision casting. The internal weight portion 120 may be a member separate from the sole portion 108. The internal weight portion 120 may be formed separately from the body member 100b. The internal weight portion 120 may be formed alone and fixed to the sole portion 108. Examples of this fixing method include welding, press-fitting, screwing, and adhesion.

[0028] The internal weight portion 120 is located on the back side of the face portion 104. The internal weight portion 120 is located at a distance from the face portion 104.

[0029] The internal weight portion 120 has a base portion 122 and a protruding portion 124 that protrudes from the base portion 122 toward the face side. The base portion 122 protrudes upward from the inner surface 108b of the sole portion 108. The base portion 122 is integral with the inner surface 108a.

[0030] The protruding portion 124 is located on the face side of the head center of gravity CG (see FIG. 7). The entire protruding portion 124 is located on the face side of the head center of gravity CG.

[0031] As shown in FIG. 7, a recess r1 that is open on the face side is formed by the internal weight portion 120 and the sole portion 108. In the longitudinal section, the most back side point b1 on the section line forming the recess r1 is determined. Further, in the longitudinal section, a straight line L1 along the vertical direction passing through this point b1 is determined. Further, an intersection point b2 between this straight line L1 and the upper surface of the internal weight portion 120 is determined. The line segment connecting the point b1 and the point b2 may be defined as the boundary between the base portion 122 and the protruding portion 124.

[0032] The protrusion 124 has an upper surface 124a and a lower surface 124b. Further, the protrusion 124 has a front end surface 124c. The front end surface 124c is the end surface on the face side of the protrusion 124. The front end surface 124c extends between the front edge of the upper surface 124a and the front edge of the lower surface 124b. The front end surface 124c may not be present. For example, when the tip of the protrusion 124 is pointed, the front end surface 124c is not formed.

[0033] The upper surface 124a is inclined so as to be on the upper side as it approaches the face portion 104. The lower surface 124b is inclined so as to be on the upper side as it approaches the face portion 104. The upper surface 124a is parallel to the lower surface 124b. The upper surface 124a may not be parallel to the lower surface 124b.

[0034] The base 122 has an upper surface 122a. The upper surface 122a is inclined so as to be on the upper side as it approaches the face portion 104. The upper surface 122a may be a flat surface or a curved surface. In the present embodiment, the upper surface 122a is a single flat surface. The upper surface 122a terminates on the back side by reaching the inner surface 108b of the sole portion 108. The upper surface 122a is inclined so as to be on the upper side as it approaches the protrusion 124. The entire upper surface of the internal weight portion 120 including the upper surface 122a and the upper surface 124a is inclined so as to be on the upper side as it approaches the face portion 104. In the internal weight portion 120, the upper surface 122a and the upper surface 124a are flush. The upper surface 122a and the upper surface 124a form a single flat surface. The upper surface 122a and the upper surface 124a may not be flush.

[0035] As shown in FIG. 7, the internal weight portion 120 has a rising surface 120d. The rising surface 120d constitutes the bottom surface in the recess r1 described above. From the viewpoint of FIG. 5, the rising surface 120d can be seen

[0036] Referring to FIGS. 6(a), 6(b) and 6(c), the internal weight portion 120 has a toe-side portion 120T, a heel-side portion 120H, and a central portion 120M. The toe-side portion 120T is located on the toe side of the central portion 120M. The toe-side portion 120T is adjacent to the central portion 120M. The heel-side portion 120H is located on the heel side of the central portion 120M. The heel-side portion 120H is adjacent to the central portion 120M. The central portion 120M is located between the toe-side portion 120T and the heel-side portion 120H. The entire toe-side portion 120T is located on the toe side of the face center Fc. The entire heel-side portion 120H is located on the heel side of the face center Fc. The toe-heel direction range of the central portion 120M includes the toe-heel direction position of the face center Fc.

[0037] The toe-side portion (toe protrusion 124T) of the protrusion 124 has a first wall thickness t1. The heel-side portion (heel protrusion 124H) of the protrusion 124 has a second wall thickness t2. The central portion (central protrusion 124M) of the protrusion 124 has a third wall thickness t3. The third wall thickness t3 is smaller than at least one of the first wall thickness t1 and the second wall thickness t2. In the present embodiment, the third wall thickness t3 is smaller than the first wall thickness t1 and smaller than the second wall thickness t2. In the present embodiment, the second wall thickness t2 is larger than the first wall thickness t1. The wall thicknesses t1, t2, and t3 can be measured along the normal line of the upper surface 124a.

[0038] In the present disclosure, the terms the first wall thickness t1, the second wall thickness t2, and the third wall thickness t3 are used, but they may not be different from each other. For example, the first wall thickness t1 and the third wall thickness t3 may be the same. Note that, as will be described later, in the central portion 120M, the protrusion 124 may not be provided.

[0039] The protrusion 124 has a toe protrusion 124T, a heel protrusion 124H, and a central protrusion 124M. The toe protrusion 124T is the toe-side portion of the protrusion 124. The toe protrusion 124T belongs to the toe-side portion 120T. The heel protrusion 124H is the heel-side portion of the protrusion 124. The heel protrusion 124H belongs to the heel-side portion 120H. The central protrusion 124M is the portion between the toe-side portion and the heel-side portion of the protrusion 124. The central protrusion 124M belongs to the central portion 120M. The toe protrusion 124T is located on the toe side of the central protrusion 124M. The toe protrusion 124T is adjacent to the central protrusion 124M. The heel protrusion 124H is located on the heel side of the central protrusion 124M. The heel protrusion 124H is adjacent to the central protrusion 124M. As described above, the central protrusion 124M may be absent.

[0040] As shown well in FIG. 3, the upper surface 122a and the upper surface 124a have a toe-side step 126 and a heel-side step 128. The height of the heel-side step 128 is greater than the height of the toe-side step 126. These heights can be measured along the vertical direction. The toe-side step 126 and the heel-side step 128 may be absent.

[0041] Due to the difference in the wall thickness of the protrusion 124, the internal weight portion 120 can be divided into a toe-side portion 120T, a heel-side portion 120H, and a central portion 120M. In the present embodiment, the lower edge 126a of the toe-side step 126 can be the boundary between the toe-side portion 120T and the central portion 120M. Also, the lower edge 128a of the heel-side step 128 can be the boundary between the heel-side portion 120H and the central portion 120M. Note that the steps 126 and 128 may be absent.

[0042] The upper surface 124a in the central protrusion 124M is located below the upper surface 124a in at least one of the toe protrusion 124T and the heel protrusion 124H. In the present embodiment, the upper surface 124a in the central protrusion 124M is located below the upper surface 124a in the toe protrusion 124T and is also located below the upper surface 124a in the heel protrusion 124H.

[0043] Figure 9 is a cross-sectional view taken along line D-D of FIG. 1. FIG. 9 is a cross-section along the toe-heel direction at the position where the protrusion 124 is present. Figure 10 is a cross-sectional view taken along line E-E of FIG. 1. FIG. 10 is a cross-section along the toe-heel direction at the position where the base 122 is present.

[0044] As shown in FIG. 10, the base 122 has a toe base 122T, a heel base 122H, and a central base 122M. The toe base 122T is located on the back side of the toe protrusion 124T (the toe-side portion of the protrusion 124). The heel base 122H is located on the back side of the heel protrusion 124H (the heel-side portion of the protrusion 124). The central base 122M is located on the back side of the central protrusion 124M (the central portion of the protrusion 124). The toe base 122T is located on the toe side of the central base 122M. The toe base 122T is adjacent to the central base 122M. The heel base 122H is located on the heel side of the central base 122M. The heel base 122H is adjacent to the central base 122M. The central base 122M is located between the toe base 122T and the heel base 122H.

[0045] As shown in FIG. 6(a), the toe base 122T has a fourth wall thickness t4. As shown in FIG. 6(c), the heel base 122H has a fifth wall thickness t5. As shown in FIGS. 6(b) and 7, the central base 122M has a sixth wall thickness t6. The wall thicknesses t4, t5, and t6 can be measured along a direction perpendicular to the upper surface 122a. The wall thicknesses t4, t5, and t6 can be the thickness from a virtual boundary surface (described later) to the upper surface 122a. That is, in the longitudinal section, the lower starting points of the wall thicknesses t4, t5, and t6 can be the straight line L2 (or the straight line L1). The straight lines L2 and L1 will be described later.

[0046] The average value of the fifth wall thickness t5 is greater than the average value of the sixth wall thickness t6. The average value of the fourth wall thickness t4 is greater than the average value of the sixth wall thickness t6. The average value of the fifth wall thickness t5 is greater than the average value of the fourth wall thickness t4. These average values can be calculated from the volume and the surface area of the upper surface. For example, when the volume of the corn base 122T is V1 and the surface area of the upper surface 122a in the corn base 122T is S1, the average value of the fourth wall thickness t4 can be set as V1 / S1. The volume of the heel base 122H is greater than the volume of the corn base 122T.

[0047] The average value of the wall thickness t5 is greater than the average value of the wall thickness t6, and the average value of the wall thickness t4 is greater than the average value of the wall thickness t6. By distributing the weight of the base 122 to the corn side and the heel side, the moment of inertia about the y-axis of the head 100 can be increased, and the high-rebound area can be expanded. The average value of the wall thickness t5 is greater than the average value of the wall thickness t4. By distributing the weight of the base 122 to the heel side, the center of gravity distance of the head 100 becomes shorter, that is, the grip can be improved. In the head 100, the sweet spot SS is located on the heel side rather than the face center Fc.

[0048] The maximum value of the wall thickness t5 is greater than the maximum value of the wall thickness t6, and the maximum value of the wall thickness t4 is greater than the maximum value of the wall thickness t6. Therefore, the moment of inertia about the y-axis of the head 100 can be increased, and the high-rebound area can be expanded. The maximum value of the wall thickness t5 is greater than the maximum value of the wall thickness t4. Therefore, the center of gravity distance of the head 100 becomes shorter, and the grip can be improved.

[0049] In FIG. 9, what is indicated by the double-headed arrow d1 is the distance between the lower surface 124b of the protrusion 124 and the inner surface 108b of the sole portion 108. This distance d1 is measured along the normal line of the inner surface 108b. This distance d1 is also referred to as the facing distance. The facing distance d1 is measured in a cross section along the corn-heel direction.

[0050] As shown in Fig. 9, in a cross-section along the toe-heel direction, the lower surface 124b of the protrusion 124 is formed along the inner surface 108b of the sole portion 108. The maximum value of the opposing distance d1 in this cross-section is defined as d1max, and the minimum value is defined as d1min. In this case, when [(d1max - d1min) / d1max] is 0.6 or less, it can be determined that it is formed along the inner surface 108b of the sole portion 108. [(d1max - d1min) / d1max] is preferably 0.60 or less, more preferably 0.55 or less, and even more preferably 0.50 or less. From the perspective of a low center of gravity, d1max is preferably 8 mm or less, more preferably 7 mm or less, and even more preferably 6 mm or less. From the perspective of separating the protrusion 124 from the inner surface 108b of the sole portion 108, d1max is preferably 1 mm or more, more preferably 1.5 mm or more, and even more preferably 2 mm or more. The position in the face-back direction of this cross-section along the toe-heel direction is not limited. For example, the position in the face-back direction of this cross-section can be the center position CP in the face-back direction of the protrusion 124. In a longitudinal section including the head center of gravity CG, the foremost point P4 of the protrusion 124 is determined (see Fig. 8). The position that bisects the distance between the foremost point P4 and the first contact point P1 in the face-back direction can be this center position CP in the face-back direction.

[0051] In the lower surface 124b of the present embodiment, a first flat portion 130 that becomes upper as it goes toward the toe side is formed in the toe protrusion 124T, a second flat portion 132 substantially parallel to the toe-heel direction is formed in the central protrusion 124M, and a third flat portion 134 that becomes upper as it goes toward the heel side is formed in the heel protrusion 124H. The lower surface 124b is composed of a plurality of flat surfaces, but is formed along the curved inner surface 108b.

[0052] The cross-section along the toe-heel direction is determined at each position in the face-back direction. Preferably, the lower surface 124b is formed along the inner surface 108b at at least one position in the face-back direction. An example of this position is the central position CP described above. More preferably, the lower surface 124b is formed along the inner surface 108b at every position in the face-back direction.

[0053] As shown in FIG. 9, the heel projection 124H is connected to the internal extension 110b of the hosel portion 110. With this configuration, the projection 124 can be disposed more on the heel side, and the center of gravity distance can be reduced. By reducing the center of gravity distance, face rotation is promoted, and thus a head with good grip can be obtained.

[0054] "Good grip" means that the face 10a is difficult to open at impact. In a head with good grip, the face 10a is likely to be square or slightly closed at impact. In a head with good grip, the energy of the head is efficiently transmitted to the ball, and the flying distance can increase with a strong trajectory. The center of gravity distance is the distance between the shaft axis and the head center of gravity.

[0055] Since the heel projection 124H is connected to the internal extension 110b, the vibration of the heel projection 124H is suppressed. Therefore, even when the central projection 124M is thinned, the vibration of the projection 124 can be suppressed. This suppression of vibration enhances the durability of the projection 124 and the internal weight portion 120. Also, this suppression of vibration can contribute to an improvement in the hitting feeling. When the vibration of the projection 124 is transmitted to the hand, the hitting feeling can deteriorate. By suppressing this vibration, the hitting feeling can be improved.

[0056] As described above, in the present embodiment, the thickness t2 of the heel-side portion (heel protrusion 124H) of the protrusion 124 is larger than the thickness t1 of the toe-side portion (toe protrusion 124T) of the protrusion 124. With this configuration, the center-of-gravity distance of the head 100 can be reduced. By reducing the center-of-gravity distance, face rotation can be promoted, and thus a head with good grip can be obtained.

[0057] The volume of the heel protrusion 124H is larger than the volume of the toe protrusion 124T. With this configuration, the center-of-gravity distance of the head 100 can be reduced. By reducing the center-of-gravity distance, a head with good grip can be obtained.

[0058] FIG. 8 is a cross-sectional view in which a part of FIG. 7 is enlarged. FIG. 8 has an enlarged portion in which the inside of circle A is enlarged.

[0059] The contact point on the face side between the internal weight portion 120 and the inner surface 108b of the sole portion 108 is defined as the first contact point P1. At the boundary portion on the face side between the internal weight portion 120 and the inner surface 108b, the vertex of the corner or the point with the minimum radius of curvature can be the first contact point P1. When the portion with the minimum radius of curvature is an arc instead of a point, the face-side end point of the arc can be the first contact point P1. As shown in FIG. 8, in the present embodiment, the first contact point P1 is such that the portion with the minimum radius of curvature is an arc, and the face-side end point of this arc is the first contact point P1. The first contact point P1 is determined in the longitudinal section.

[0060] The contact point on the back side between the internal weight portion 120 and the inner surface 108b of the sole portion 108 is defined as the second contact point P2. At the boundary portion on the back side between the internal weight portion 120 and the inner surface 108b, the vertex of the corner or the point with the minimum radius of curvature can be the second contact point P2. When the portion with the minimum radius of curvature is an arc instead of a point, the back-side end point of the arc can be the second contact point P2. As shown in FIG. 8, in the present embodiment, the second contact point P2 is the vertex of the corner. The second contact point P2 is determined in the longitudinal section.

[0061] When the internal weight portion 120 is formed separately from the body member 100b, there may be an interface surface that separates the base portion 122 from the sole portion 108. In the present embodiment, the base portion 122 is integral with the sole portion 108, and this interface surface does not exist. In this case, a virtual interface surface that separates the base portion 122 from the sole portion 108 can be defined. The longitudinal section can be set at any position in the toe-heel direction. In each longitudinal section, a line segment L2 connecting the first contact point P1 and the second contact point P2 can be determined (see FIG. 8). The set of these line segments L2 can be the virtual interface surface. By this virtual interface surface, the internal weight portion 120 can be separated from the sole portion 108. The independent internal weight portion 120 can be defined by the interface surface or the virtual interface surface. As a result, for example, the volume of the base portion 122 and the wall thickness of the base portion 122 can be determined.

[0062] In FIG. 8, what is indicated by the double-headed arrow s1 is the wall thickness of the sole portion 8 at the first contact point P1. The wall thickness s1 is measured along the vertical direction. In the present application, the wall thickness of the sole portion 8 is measured along the vertical direction.

[0063] The sole portion 108 has a sole front portion 108c with a wall thickness greater than s1. The sole front portion 108c is located on the face side of the first contact point P1. In the present embodiment, the sole front portion 108c is adjacent to the first contact point P1. The sole front portion 108c may be separated from the first contact point P1.

[0064] The sole front portion 108c with a wall thickness greater than s1 extends from the first contact point P1 toward the face side and extends at least to the boundary k1. The face-back direction length of the sole front portion 108c is not limited.

[0065] The sole part 108 has a first thin part 108d. The thickness s1 at the first contact point P1 is made smaller than the thickness of the front part 108c of the sole, so that the first thin part 108d is formed at the position of the first contact point P1. The sole part 108 at the first contact point P1 is referred to as the first thin part 108d. The sole part 108 has a first thin part 108d that is thinner than the front part 108c of the sole at the position of the first contact point P1. Whether the first thin part 108d is formed is judged in the longitudinal section. The thickness s1 of the first thin part 108d may vary depending on the position in the toe - heel direction.

[0066] In this embodiment, the first thin part 108d is the thinnest in the range from the first contact point P1 to the boundary k1. In this embodiment, the first thin part 108d is the thinnest in the range from the first contact point P1 to the leading edge Le.

[0067] The sole part 108 has a thickness transition part 108e. In the thickness transition part 108e, the thickness continuously decreases as it approaches the first contact point P1. The thickness transition part 108e has an upper surface 140. The upper surface 140 is a part of the inner surface 108b of the sole part 108. The upper surface 140 is inclined so as to go downward as it approaches the first contact point P1. In the embodiment of FIG. 8, from the first contact point P1 to the point P3 is the thickness transition part 108e. The point P3 is located in the front part 108c of the sole. The point P3 is the most face - side point on the upper surface 140 of the thickness transition part 108e. In this embodiment, throughout the thickness transition part 108e, its thickness is equal to or greater than the thickness s1. The thickness transition part 108e may have a part that is thinner than the thickness s1.

[0068] In this embodiment, the wall thickness transition portion 108e is in contact with the first contact point P1. The wall thickness transition portion 108e starts from the first contact point P1. The first contact point P1 and the wall thickness transition portion 108e may be separated. For example, there may be a portion with a constant wall thickness between the first contact point P1 and the wall thickness transition portion 108e. For example, there may be a portion where the wall thickness increases as it approaches the first contact point P1 between the first contact point P1 and the wall thickness transition portion 108e. There may be a portion where the wall thickness is thinner than s1 between the first contact point P1 and the wall thickness transition portion 108e.

[0069] The wall thickness transition portion 108e contributes to the relaxation of stress concentration in the first thin wall portion 108d. In addition, since the wall thickness transition portion 108e is thinner than the wall thickness at the point P3, it contributes to increasing the deformation of the face portion 104 during impact. These are the synergistic effects between the wall thickness transition portion 108e and the first thin wall portion 108d.

[0070] The wall thickness transition portion 108e is provided near the first contact point P1. By positioning the wall thickness transition portion 108e near the first contact point P1, the synergistic effect is enhanced. This "nearby" may mean that the distance from the first contact point P1 is within 5 mm. This distance is measured along the face-back direction. What is indicated by the double arrow W1 in FIG. 8 is the distance between the point P3 and the first contact point P1. From the viewpoint of the synergistic effect between the first thin wall portion 108d and the wall thickness transition portion 108e, the distance W1 is preferably 5 mm or less, more preferably 4 mm or less, and even more preferably 3 mm or less. This distance W1 is measured along the face-back direction.

[0071] What is indicated by the double arrow W2 in FIG. 8 is the width of the wall thickness transition portion 108e. The width W2 is measured along the face-back direction. In this embodiment, the width W2 is equal to the distance W1. The width W2 may be different from the distance W1.

[0072] From the viewpoint of reducing stress concentration in the first thin-wall portion 108d and increasing the deformation of the face portion 104, the width W2 is preferably 0.6 mm or more, more preferably 0.8 mm or more, and still more preferably 1.0 mm or more. If the width W2 is too large, the inclination angle of the upper surface 140 becomes too small, and the effect of reducing stress concentration may decrease. From this viewpoint, the width W2 is preferably 5 mm or less, more preferably 4 mm or less, and still more preferably 3 mm or less.

[0073] As shown in FIGS. 6(b), 7, and 8, the first thin-wall portion 108d is formed on the face side of the central portion 120M. In other words, the first thin-wall portion 108d is formed in the toe-heel direction range where the central portion (central protrusion 124M) of the protrusion 124 exists. The wall thickness transition portion 108e is also formed on the face side of the central portion 120M. These first thin-wall portion 108d and wall thickness transition portion 108e can enhance the repulsive performance in the central region of the face portion 104. As shown in FIG. 6(a), the first thin-wall portion 108d is not formed on the face side of the toe-side portion 120T. In other words, the first thin-wall portion 108d is not formed in the toe-heel direction range where the toe-side portion (toe protrusion 124T) of the protrusion 124 exists. The wall thickness transition portion 108e is also not formed on the face side of the toe-side portion 120T. As shown in FIG. 6(c), the first thin-wall portion 108d is not formed on the face side of the heel-side portion 120H. In other words, the first thin-wall portion 108d is not formed in the toe-heel direction range where the heel-side portion (heel protrusion 124H) of the protrusion 124 exists. The wall thickness transition portion 108e is also not formed on the face side of the heel-side portion 120H. By not forming thin-wall portions on the toe side and the heel side, the left-right moment of inertia can be improved.

[0074] In the longitudinal section including the head center of gravity CG, the back side end of the internal weight portion 120 is located on the back side of the head center of gravity CG (see FIG. 7). In the present embodiment, the back side end of the internal weight portion 120 is the second contact point P2. On the other hand, as described above, the center of gravity of the protruding portion 124 is located on the face side of the head center of gravity CG. Further, the center of gravity of the internal weight portion 120 is located on the face side of the head center of gravity CG. As shown in FIG. 7, in the base portion 122, the portion where the upper surface 122a is inclined so as to become lower toward the back side extends to the back side of the head center of gravity CG. With this configuration, more weight can be distributed on the lower side of the head 100. On the other hand, by setting the center of gravity of the protruding portion 124 to be on the face side of the head center of gravity CG, the center of gravity depth is reduced. Due to these synergistic effects, the position of the sweet spot SS is lowered. This effect is further enhanced by setting the center of gravity of the internal weight portion 120 to be on the face side of the head center of gravity CG. This effect is further enhanced by setting the center of gravity of the base portion 122 to be on the face side of the head center of gravity CG.

[0075] Referring to FIGS. 6(a), 6(b) and 6(c), the lower surface 124b of the protruding portion 124 and the inner surface 108b of the sole portion 108 face each other so that an undercut is not formed. That is, a draft gradient is formed between the lower surface 124b and the inner surface 108b, or the lower surface 124b and the inner surface 108b are parallel. In the present embodiment, a draft gradient is formed. That is, the distance between the lower surface 124b and the inner surface 108b continuously increases as it approaches the opening of the recess r1. Therefore, in the integral molding of the sole portion 108 and the internal weight portion 120, it becomes easy to remove the mold. When lost wax precision casting is employed, it becomes easy to remove the mold in the wax molding. When an undercut is formed, it may be necessary to divide the mold to accommodate the undercut, but this division can be avoided.

[0076] Referring to the enlarged portion of FIG. 8, the lower surface 124b of the protruding portion 124 and the upper surface 140 of the wall thickness transition portion 108e face each other so that no undercut is formed. That is, a draft gradient is formed between the lower surface 124b and the upper surface 140, or the lower surface 124b and the upper surface 140 are parallel. In the present embodiment, a draft gradient is formed. That is, the distance between the lower surface 124b and the upper surface 140 continuously increases as it approaches the opening of the recess r1. Therefore, in the integral molding of the sole portion 108 and the internal weight portion 120, it becomes easy to remove the mold. When lost wax precision casting is employed, it becomes easy to remove the mold in the wax molding. When an undercut is formed, it may be necessary to divide the mold to accommodate the undercut, but this division can be avoided.

[0077] FIG. 11 is a longitudinal sectional view of a head 150 which is a modification of the first embodiment. The position of the section in FIG. 11 is the same as the position of the B-B line in FIG. 1. Except for the inclination angle of the upper surface 124a of the protruding portion 124, the head 150 is the same as the head 100.

[0078] Also in the head 150, the upper surface 124a is inclined so as to be on the upper side as it approaches the face portion 104. However, in the head 150, the upper surface 124a is not parallel to the lower surface 124b. The upper surface 124a is inclined so that the wall thickness of the protruding portion 124 decreases as it approaches the face portion 104. A taper is formed on the protruding portion 124 such that its wall thickness becomes thinner as it approaches the tip. With this configuration, it becomes even easier to remove the mold in the integral molding of the sole portion 108 and the internal weight portion 120.

[0079] When the thickness of the protruding portion 124 changes as in the head 150, the first wall thickness t1, the second wall thickness t2, and the third wall thickness t3 can be interpreted as average values. This average value can be calculated from the volume and the surface area of the upper surface. For example, when the volume of the toe protruding portion 124T is Va and the surface area of the upper surface 124a in the toe protruding portion 124T is Sa, the average value of the first wall thickness t1 can be Va / Sa.

[0080] In FIG. 4, the area indicated by the double-headed arrow HA is the impact area. The position 0.84 inches (21.335 mm) away from the face center Fc toward the toe side is T20. The position 0.84 inches away from the face center Fc toward the heel side is H20. The area from the position T20 to the position H20 is the impact area HA. The length of the impact area HA (the length in the toe-heel direction) is 1.68 inches.

[0081] In this embodiment, the entire central portion 120M exists in the impact area HA. The entire central base portion 122M exists in the impact area HA. The entire central protrusion portion 124M exists in the impact area HA.

[0082] From the viewpoint of expanding the high-rebound area in the toe-heel direction, it is preferable that the first thin portion 108d extends from the toe side to the heel side to form a laterally extending portion 108f. It is preferable that the first thin portion 108d is provided in 80% or more of the impact area HA. That is, the length in the toe-heel direction of the laterally extending portion 108f existing in the impact area HA is preferably 80% or more of the length of the impact area HA. With this configuration, the rebound performance can be improved in the face area where the hitting probability is high.

[0083] From the viewpoint of increasing the moment of inertia about the left and right axes while enhancing the resilience performance in the impact area HA, it is preferable that the entire laterally extending portion 108f is provided in the impact area HA. From the viewpoint of increasing the moment of inertia about the left and right axes, it is preferable that the first thin-walled portion 108d is not formed on the toe side and the heel side of the impact area HA. From the viewpoint of increasing the moment of inertia about the left and right axes, it is preferable that the first thin-walled portion 108d is not formed on the toe side of the laterally extending portion 108f, and it is preferable that the first thin-walled portion 108d is not formed on the heel side of the laterally extending portion 108f. From the viewpoint of increasing the moment of inertia about the left and right axes, it is preferable that the wall thickness s1 on the toe side relative to the laterally extending portion 108f is larger than the wall thickness s1 in the laterally extending portion 108f. From the viewpoint of increasing the moment of inertia about the left and right axes, it is preferable that the wall thickness s1 on the heel side relative to the laterally extending portion 108f is larger than the wall thickness s1 in the laterally extending portion 108f.

[0084] The toe-side portion 120T has a portion on the toe side of the position T20. The toe base 122T has a portion on the toe side of the position T20. The toe projection 124T has a portion on the toe side of the position T20. The heel-side portion 120H has a portion on the heel side of the position H20. The heel base 122H has a portion on the heel side of the position H20. The heel projection 124H has a portion on the heel side of the position H20. These configurations contribute to the improvement of the moment of inertia about the left and right axes.

[0085] [Second Embodiment] FIG. 12 is a plan view of the golf club head 200 of the second embodiment, FIG. 13 is a perspective view of the body member 200b of the head 200, and FIG. 14 is a front view of the body member 200b. FIG. 15(a) is a longitudinal sectional view taken along the line A-A of FIG. 12. FIG. 15(b) is a longitudinal sectional view taken along the line B-B of FIG. 12. FIG. 15(c) is a longitudinal sectional view taken along the line C-C of FIG. 12. In appearance, the head 200 is the same as the head 100.

[0086] The head 200 has a face portion 204, a crown portion 206, a sole portion 208, and a hosel portion 210. The sole portion 208 has an outer surface 208a and an inner surface 208b. The hosel portion 210 has an exposed portion 210a that is exposed to the outside and an internal extending portion 210b that is located inside the head 200. Further, the hosel portion 210 has a hosel hole 212. The face portion 204 has a striking face 204a.

[0087] From the perspective of components, the head 200 has a face member 200a and a body member 200b. The face member 200a is welded to the body member 200b. In FIGS. 15(a), 15(b), and 15(c), the boundary k1 between the face member 200a and the body member 200b is shown.

[0088] The head 200 has an internal weight portion 220. The body member 200b has the internal weight portion 220. The internal weight portion 220 is provided inside the sole portion 208. The internal weight portion 220 is provided on the inner surface 208b of the sole portion 208.

[0089] The internal weight portion 220 is integral with the sole portion 208. The internal weight portion 220 is integrally formed with the sole portion 208. The internal weight portion 220 is integral with the body member 200b. The entire body member 200b including the internal weight portion 220 is integrally formed.

[0090] The internal weight portion 220 has a base portion 222 and a protruding portion 224 that protrudes from the base portion 222 toward the face side. The base portion 222 is integral with the inner surface of the sole portion 208.

[0091] The protruding portion 224 has an upper surface 224a and a lower surface 224b. Further, the protruding portion 224 has a front end surface 224c. The upper surface 224a is inclined so as to be on the upper side as it approaches the face portion 204. The lower surface 224b is inclined so as to be on the upper side as it approaches the face portion 204.

[0092] The base 222 has an upper surface 222a. The upper surface 222a is inclined so as to be upward as it approaches the face portion 204.

[0093] Referring to FIGS. 15(a), 15(b) and 15(c), the internal weight portion 220 has a toe side portion 220T, a heel side portion 220H, and a central portion 220M.

[0094] The protruding portion 224 has a toe protruding portion 224T and a heel protruding portion 224H. As described above, there is no central protruding portion. In the present embodiment, the portion without the protruding portion 224 is defined as the central portion 220M, the portion on the toe side of this central portion 220M is defined as the toe side portion 220T, and the portion on the heel side of this central portion 220M can be defined as the heel side portion 220H.

[0095] As well shown in FIG. 13, the upper surface 222a has a toe side step 226 and a heel side step 228. The lower edge 226a of the toe side step 226 can be the boundary between the toe side portion 220T and the central portion 220M. The lower edge 228a of the heel side step 228 can be the boundary between the heel side portion 220H and the central portion 220M.

[0096] The toe protruding portion 224T has a first wall thickness t1. The heel protruding portion 224H has a second wall thickness t2. Except that the central portion 220M of the internal weight portion 220 has no protruding portion, the head 200 is the same as the head 100.

[0097] FIG. 16 is a cross-sectional view taken along the line D-D of FIG. 12. FIG. 16 is a cross-section along the toe-heel direction at the position where the protruding portion 224 exists. FIG. 17 is a cross-sectional view taken along the line E-E of FIG. 12. FIG. 17 is a cross-section along the toe-heel direction at the position where the base 222 exists. The base 222 has a toe base 222T, a heel base 222H, and a central base 222M. As shown in FIG. 17, the base 222 is the same as the base 122 of the head 100. However, as shown in FIG. 16, for the protruding portion 224, unlike the protruding portion 124 of the head 100, the central portion is missing.

[0098] [Third Embodiment] FIG. 18 is a plan view of a golf club head 300 according to the third embodiment, FIG. 19 is a perspective view of a body member 300b of the head 300, and FIG. 20 is a front view of the body member 300b. FIG. 21(a) is a longitudinal sectional view taken along line A-A of FIG. 18. FIG. 21(b) is a longitudinal sectional view taken along line B-B of FIG. 18. FIG. 21(c) is a longitudinal sectional view taken along line C-C of FIG. 18. In appearance, the head 300 is the same as the head 100.

[0099] The head 300 has a face portion 304, a crown portion 306, a sole portion 308, and a hosel portion 310. The sole portion 308 has an outer surface 308a and an inner surface 308b. The hosel portion 310 has a hosel hole 312. The face portion 304 has a striking face 304a.

[0100] From the perspective of components, the head 300 has a face member 300a and a body member 300b. The face member 300a is welded to the body member 300b. In FIGS. 21(a), 21(b), and 21(c), a boundary k1 between the face member 300a and the body member 300b is shown.

[0101] The head 300 has an internal weight portion 320. The body member 300b has the internal weight portion 320. The internal weight portion 320 is provided inside the sole portion 308. The internal weight portion 320 is provided on the inner surface 308b of the sole portion 308.

[0102] The internal weight portion 320 has a base portion 322 and a protruding portion 324 that protrudes from the base portion 322 toward the face side. The base portion 322 is integral with the inner surface of the sole portion 308.

[0103] The protruding portion 324 has an upper surface 324a and a lower surface 324b. Further, the protruding portion 324 has a front end surface 324c. The upper surface 324a is inclined so as to be on the upper side as it approaches the face portion 304. The lower surface 324b is inclined so as to be on the upper side as it approaches the face portion 304.

[0104] The base portion 322 has an upper surface 322a. The upper surface 322a is inclined so as to be on the upper side as it approaches the face portion 304.

[0105] Referring to FIGS. 21(a), 21(b) and 21(c), the internal weight portion 320 has a toe-side portion 320T, a heel-side portion 320H, and a central portion 320M.

[0106] FIG. 22 is a cross-sectional view taken along line D-D of FIG. 18. FIG. 22 is a cross-section along the toe-heel direction at the position where the protrusion 324 is present. FIG. 23 is a cross-sectional view taken along line E-E of FIG. 18. FIG. 23 is a cross-section along the toe-heel direction at the position where the base portion 322 is present. As shown in FIG. 22, the protrusion 324 has a toe protrusion 324T, a central protrusion 324M, and a heel protrusion 324H. As shown in FIG. 23, the base portion 322 has a toe base 322T, a heel base 322H, and a central base 322M. In the toe-side portion 320T of the internal weight portion 320, not only the protrusion 324T but also the base portion 322T is thin.

[0107] As shown in FIG. 21(a), the toe protrusion 324T has a first wall thickness t1. As shown in FIG. 21(c), the heel protrusion 324H has a second wall thickness t2. As shown in FIG. 21(b), the central protrusion 324 has a third wall thickness t3. The second wall thickness t2 is larger than the third wall thickness t3. On the other hand, the first wall thickness t1 is the same as the third wall thickness t3. Except that the wall thickness t1 is the same as the wall thickness t3, the head 300 is the same as the head 100. In the head 300, there is no step that can be a boundary between the central protrusion 324M and the toe protrusion 324T on the upper surface 324a. In the internal weight portion 320, any position on the toe side of the face center Fc can be a boundary between the toe-side portion 320T and the central portion 320M.

[0108] [Fourth Embodiment] FIG. 24 is a plan view of the golf club head 400 according to the fourth embodiment, FIG. 25 is a perspective view of the body member 400b of the head 400, and FIG. 26 is a front view of the body member 400b. FIG. 27(a) is a longitudinal sectional view taken along the line A-A of FIG. 24. FIG. 27(b) is a longitudinal sectional view taken along the line B-B of FIG. 24. FIG. 27(c) is a longitudinal sectional view taken along the line C-C of FIG. 24. In appearance, the head 400 is the same as the head 100.

[0109] The head 400 has a face portion 404, a crown portion 406, a sole portion 408, and a hosel portion 410. The sole portion 408 has an outer surface 408a and an inner surface 408b. The hosel portion 410 has a hosel hole 412. The face portion 404 has a striking face 404a.

[0110] From the perspective of components, the head 400 has a face member 400a and a body member 400b. The face member 400a is welded to the body member 400b. In FIGS. 27(a), 27(b), and 27(c), the boundary k1 between the face member 400a and the body member 400b is shown.

[0111] The head 400 has an internal weight portion 420. The body member 400b has the internal weight portion 420. The internal weight portion 420 is provided inside the sole portion 408. The internal weight portion 420 is provided on the inner surface 408b of the sole portion 408.

[0112] The internal weight portion 420 has a base portion 422 and a protruding portion 424 that protrudes from the base portion 422 toward the face side. The base portion 422 is integral with the inner surface of the sole portion 408.

[0113] The protruding portion 424 has an upper surface 424a and a lower surface 424b. Further, the protruding portion 424 has a front end surface 424c. The upper surface 424a is inclined so as to be on the upper side as it approaches the face portion 404. On the other hand, the lower surface 424b extends substantially parallel to the face-back direction. Substantially parallel may mean that the inclination angle with respect to the face-back direction is 10° or less.

[0114] The inner surface 408b of the sole part 408 is substantially parallel to the lower surface 424b. The inner surface 408b and the lower surface 424b face each other so that no undercut is formed.

[0115] The base 422 has an upper surface 422a. The upper surface 422a is inclined so as to be on the upper side as it approaches the face part 404.

[0116] Referring to FIGS. 27(a), 27(b) and 27(c), the internal weight part 420 has a toe-side part 420T, a heel-side part 420H, and a central part 420M.

[0117] FIG. 28 is a cross-sectional view taken along line D-D of FIG. 24. FIG. 28 is a cross-section along the toe-heel direction at the position where the protrusion 424 exists. FIG. 29 is a cross-sectional view taken along line E-E of FIG. 24. FIG. 29 is a cross-section along the toe-heel direction at the position where the base 422 exists. As shown in FIG. 28, the protrusion 424 has a toe protrusion 424T, a central protrusion 424M, and a heel protrusion 424H. As shown in FIG. 29, the base 422 has a toe base 422T, a heel base 422H, and a central base 422M.

[0118] As shown in FIG. 27(a), the toe-side protrusion 424T has a first wall thickness t1. As shown in FIG. 27(c), the heel-side protrusion 424H has a second wall thickness t2. As shown in FIG. 27(b), the central protrusion 424M has a third wall thickness t3. The toe protrusion 424T forms a wall thickness change part 425T in which the first wall thickness t1 continuously increases as it approaches the face part 404. The heel protrusion 424H forms a wall thickness change part 425H in which the second wall thickness t2 continuously increases as it approaches the face part 404. The central protrusion 424M forms a wall thickness change part 425M in which the third wall thickness t3 continuously increases as it approaches the face part 404. The protrusion 424 forms a wall thickness change part 425 in which its wall thickness continuously increases as it approaches the face part 404.

[0119] The second wall thickness t2 is greater than the third wall thickness t3. The first wall thickness t1 is greater than the third wall thickness t3. The second wall thickness t2 is greater than the first wall thickness t1. When the wall thicknesses t1, t2, and t3 are changing, the wall thicknesses t1, t2, and t3 can be interpreted as average values.

[0120] The maximum value of the second wall thickness t2 is greater than the maximum value of the third wall thickness t3. The maximum value of the first wall thickness t1 is greater than the maximum value of the third wall thickness t3. The maximum value of the second wall thickness t2 is greater than the maximum value of the first wall thickness t1.

[0121] In FIG. 28, what is indicated by the double arrow d1 is the distance between the lower surface 424b of the protrusion 424 and the inner surface 408b of the sole portion 408. As described above, this distance d1 is also referred to as the facing distance.

[0122] As shown in FIG. 28, in a cross-section along the toe-heel direction, the lower surface 424b of the protrusion 424 is formed so as to follow the inner surface 408b of the sole portion 408. In this cross-section, the inner surface 408b of the sole portion 408 is curved so as to be convex downward. In this cross-section, the lower surface 424b is also curved so as to be convex downward. As described above, in this cross-section, the maximum value d1max and the minimum value d1min of the facing distance d1 are determined. In the present embodiment, [(d1max - d1min) / d1max] can be 0.2 or less, further 0.15 or less, and further 0.1 or less. Also, d1max can be 3.5 mm or less, further 3 mm or less, and further 2.5 mm or less.

[0123] The first embodiment (head 100), the second embodiment (head 200), the third embodiment (head 300), and the fourth embodiment (head 400) described above can exhibit the following effects. In the description applicable to a plurality of embodiments, when there are a plurality of reference numerals, the description of the reference numerals is appropriately omitted.

[0124] Each embodiment has an internal weight portion at a position spaced apart from the face portion. Providing the internal weight portion on the inner surface of the sole portion can increase the rigidity of the sole portion. However, by disposing the internal weight portion at a distance from the face portion, it is possible to avoid the increase in the rigidity of the portion near the face of the sole portion due to the internal weight portion. Therefore, at the time of impact, the portion near the face of the sole portion is likely to bend, and the repulsion performance can be improved. Further, the internal weight portion can lower the head center of gravity CG and improve the repulsion performance at the lower impact point. The lower impact point means that the impact point is in the lower region of the striking face. The striking of a ball placed directly on the ground without being teed up often results in a lower impact point. The improvement in the repulsion performance at the lower impact point is advantageous for the striking of a ball placed directly on the ground.

[0125] By means of the protruding portion extending toward the face side, the head center of gravity CG can be positioned in front of the head (face side). Therefore, the sweet spot SS can be positioned below the striking face, and the repulsion performance at the lower impact point can be improved.

[0126] Note that the sweet spot SS is the intersection of the normal line of the striking face passing through the head center of gravity CG and the striking face (see FIG. 7). Since the golf club head has a loft angle, when the head center of gravity CG is positioned in front of the head, the sweet spot SS is likely to be on the lower side of the face. This tendency becomes stronger as the loft angle is larger.

[0127] In the head 100, the head 300, and the head 400, the thickness of at least one of the toe side portion and the heel side portion of the protruding portion is thicker than the thickness of the central portion. Therefore, the weight of the protruding portion is distributed to the toe side and / or the heel side, and the moment of inertia about the left and right axes of the head can be increased. Thus, while improving the directional stability of the hit ball, the high repulsion area on the face can be expanded. The moment of inertia about the left and right axes is the moment of inertia about an axis extending in the vertical direction passing through the head center of gravity CG.

[0128] In the heads 100 and 400, the thickness of the toe-side portion and the heel-side portion of the protrusion is thicker than the thickness of the central portion. Therefore, the weight of the protrusion is distributed to the toe side and the heel side, and the moment of inertia of the head about the left-right axis can be made even larger.

[0129] In the head 200, the protrusion 224 has its toe-side portion (toe protrusion 224T) and heel-side portion (heel protrusion 224H), but the central portion in the toe-heel direction is missing. In other words, while the toe-side portion 220T and the heel-side portion 220H of the internal weight portion 220 have protrusions, the central portion 220M of the internal weight portion 220 does not have a protrusion. Therefore, the weight of the protrusion is distributed to the toe side and the heel side, and the moment of inertia of the head about the left-right axis can be increased. Thus, while improving the directional stability of the ball hit, the high-rebound area on the face can be expanded. Also, by leaving a base (central base 222M) in the central portion 220M, the weight of the internal weight portion 220 can be increased.

[0130] In all embodiments, the thickness of at least one of the toe-side portion and the heel-side portion of the base is thicker than the thickness of the central portion. Therefore, the weight of the base is distributed to the toe side and / or the heel side. Due to the synergistic effect of the protrusion and the base, the moment of inertia of the head about the left-right axis can be made even larger. Thus, while improving the directional stability of the ball hit, the high-rebound area on the face can be further expanded.

[0131] In heads 100, 300, and 400, the upper surface of the central portion (central protrusion) of the protrusion is located below the upper surface of at least one of its toe-side portion (toe protrusion) and heel-side portion (heel protrusion). Further, in heads 100 and 400, the upper surface of the central portion (central protrusion) of the protrusion is located below the upper surfaces of its toe-side portion (toe protrusion) and heel-side portion (heel protrusion). Therefore, it is possible to lower the center of gravity of the head. Also, the shape of this upper surface of the protrusion conforms to the shape of the sole portion that is curved in the toe-heel direction and lower in the center, and is effective in lowering the head center of gravity CG while being disposed inside the sole portion.

[0132] In all embodiments, the upper surface of the central portion (central base) of the base is located below the upper surface of at least one of its toe-side portion (toe base) and heel-side portion (heel base). Further, in heads 100, 200, and 400, the upper surface of the central portion (central protrusion) of the protrusion is located below the upper surfaces of its toe side (toe protrusion) and heel side (heel protrusion). Therefore, it is possible to lower the center of gravity of the head. Also, the shape of this upper surface of the base conforms to the sole shape that is curved in the toe-heel direction and lower in the center, and is effective in lowering the head center of gravity CG while being disposed inside the sole portion. The shape of this upper surface of the base can cooperate with the shape of the upper surface of the protrusion described above to lower the head center of gravity CG.

[0133] In all embodiments, the lower surface of the protrusion is formed to follow the inner surface of the sole portion in a cross section along the toe-heel direction (see FIGS. 9, 16, 22, and 28). The shape of this lower surface of the protrusion contributes to ensuring the thickness of the protrusion while extending the protrusion downward while separating the protrusion from the sole portion. In the case of a sole shape that is curved in the toe-heel direction and lower in the center, the shape of this lower surface of the protrusion is effective in lowering the head center of gravity CG while conforming to the sole shape.

[0134] In all embodiments, the protrusion is located on the face side with respect to the head center of gravity CG. Thus, the head center of gravity CG can be positioned in front of the head, and the position of the sweet spot SS can be lowered. Further, since the protrusion is separated from the sole portion, it is possible to avoid an increase in the rigidity of the portion near the face of the sole portion.

[0135] In all embodiments, the lower surface of the protrusion and the inner surface of the sole portion face each other so that an undercut is not formed (see FIGS. 6, 15, 21, and 27). Further, in the sole portion, a wall thickness transition portion is provided in the vicinity of the face side of the internal weight body, and the lower surface of the protrusion and the upper surface of the wall thickness transition portion face each other so that an undercut is not formed. For this reason, when the protrusion and the sole portion are integrally molded, it becomes easy to remove the mold.

[0136] In the heads 100, 200, and 300, the upper surface of the protrusion extends parallel to the lower surface of the protrusion. This configuration is effective in distributing the weight of the protrusion to the front side and the lower side, and helps to lower the sweet spot SS.

[0137] In the modification example (head 150) of FIG. 11, the wall thickness of the protrusion 124 decreases as it approaches the face portion 104. This configuration is effective in distributing the weight of the protrusion 124 to the lower side, and helps to lower the sweet spot SS. Further, since the shape of the protrusion 124 has a draft gradient, it becomes even easier to remove the mold in the integral molding of the sole portion 108 and the internal weight portion 120.

[0138] In FIG. 8, what is indicated by the double-headed arrow W3 is the distance between the leading edge Le and the first contact point P1. This distance is measured along the face-back direction. The leading edge Le can be the foremost point in the longitudinal section.

[0139] From the perspective of lowering the sweet spot SS by setting the head center of gravity CG closer to the face, the distance W3 is preferably 25 mm or less, more preferably 24 mm or less, and even more preferably 23 mm or less. From the perspective of increasing the deflection in the region near the face of the sole portion, the distance W3 is preferably 10 mm or more, more preferably 12 mm or more, and even more preferably 14 mm or more.

[0140] As shown in FIG. 8, the thickness s1 of the first contact point P1 (the first thin-walled portion 108d) is smaller than the thickness of the sole portion (the front sole portion 108c) in front of the first contact point P1. This first thin-walled portion 108d can be a starting point for the deformation of the sole portion 108 during impact. When the starting point of the deformation is on the back side and the distance between the starting point of the deformation and the face portion 104 increases, the deformation (or displacement) of the face portion 104 becomes larger. As a result, the repulsion performance can be improved. Also from the perspective of increasing the distance between the first thin-walled portion 108d and the face portion 104 to enhance the repulsion performance, the distance W3 is preferably 10 mm or more, more preferably 12 mm or more, and even more preferably 14 mm or more.

[0141] From the perspective of repulsion performance, the thickness s1 is preferably 1.2 mm or less, more preferably 1.1 mm or less, and even more preferably 1.0 mm or less. From the perspective of the strength of the sole portion, the thickness s1 is preferably 0.5 mm or more, more preferably 0.6 mm or more, and even more preferably 0.7 mm or more.

[0142] In FIG. 1, what is indicated by the double-headed arrow W4 is the center of gravity depth. The center of gravity depth W4 is the distance between the shaft axis Z and the head center of gravity CG. The center of gravity depth W4 is measured along the face-back direction.

[0143] From the perspective of lowering the sweet spot SS, the center of gravity depth W4 is preferably 15 mm or less, more preferably 14.5 mm or less, and even more preferably 14 mm or less. From the perspective of increasing the deflection in the region near the face of the sole portion, it is not preferable for the distance W3 to be too small. From this perspective, the center of gravity depth W4 is preferably 11 mm or more, more preferably 11.5 mm or more, and even more preferably 12 mm or more.

[0144] In FIG. 7, what is indicated by the double arrow H1 is the height of the head center of gravity CG. The height H1 is the height from the ground plane GP in the reference state. The height H1 is measured along the vertical direction.

[0145] From the viewpoint of lowering the sweet spot SS, the height H1 is preferably 15 mm or less, more preferably 14.5 mm or less, and still more preferably 14 mm or less. Considering the length of the hosel portion 110 and the height of the head, the height H1 is preferably 12 mm or more, more preferably 12.5 mm or more, and still more preferably 13 mm or more.

[0146] In FIG. 7, what is indicated by the double arrow H2 is the height of the sweet spot SS. The height H2 is the height from the ground plane GP in the reference state. The height H2 is measured along the vertical direction.

[0147] From the viewpoint of enhancing the repulsion performance in the hit of a ball placed directly on the ground, the height H2 is preferably 23 mm or less, more preferably 22.5 mm or less, and still more preferably 22 mm or less. Considering the lower limit of the height H1 and the loft angle, the height H2 is preferably 18.5 mm or more, more preferably 19 mm or more, and still more preferably 19.5 mm or more.

[0148] In FIG. 1, what is indicated by the reference sign PL1 is a plane that bisects the head 100 in the face-back direction. The plane PL1 is a plane perpendicular to the ground plane GP in the reference state. The plane PL1 is parallel to the toe-heel direction. The plane PL1 is perpendicular to the face-back direction.

[0149] By the plane PL1, the head 100 is divided into a portion on the face side of the plane PL1 and a portion on the back side of the plane PL1. From the perspective of making the head center of gravity CG closer to the face, the ratio of the weight on the face side of the plane PL1 to the total weight of the head is preferably 63% or more, more preferably 64% or more, and even more preferably 65% or more. Considering the face-back direction width of the head, this ratio is preferably 90% or less, more preferably 89% or less, and even more preferably 88% or less.

[0150] Fairway wood type heads and hybrid type heads have a larger loft angle compared to driver heads. For this reason, in these heads, when the center of gravity depth W4 is reduced, the degree to which the sweet spot SS decreases is large. In addition, in these heads, there are many opportunities to hit a ball placed directly on the ground rather than a teed-up ball. Therefore, the above-described effect of lowering the height H2 of the sweet spot SS is particularly effective in fairway wood type heads and hybrid type heads. From this perspective, fairway wood type and hybrid type heads are preferred.

[0151] As described above, the larger the loft angle, the greater the degree to which the sweet spot SS decreases when the center of gravity depth W4 is reduced. From this perspective, the loft angle is preferably 13° or more, more preferably 15° or more, and even more preferably 17° or more. Considering the specifications of fairway wood type heads and hybrid type heads, the loft angle is preferably 35° or less, more preferably 33° or less, and even more preferably 31° or less. This loft angle is the actual loft angle.

[0152] From the perspective that fairway wood type heads and hybrid type heads are preferred, the head volume is preferably 300 cm 3 or less, more preferably 250 cm 3 or less, and even more preferably 200 cm 3 or less. From the same perspective, the head volume is preferably 90 cm 3 or more, more preferably 100 cm 3 or more, and even more preferably 110 cm3 The above is more preferable.

[0153] As described above, in all embodiments, the weight of the protruding portion is distributed more on the toe side and / or the heel side, and the left-right moment of inertia can be increased. From this perspective, the left-right moment of inertia of the head is 2000 g·cm 2 or more is preferable, 2050 g·cm 2 or more is more preferable, 2100 g·cm 2 or more is more preferable. Considering the volume of the fairway wood type head and the hybrid type head, the left-right moment of inertia of the head is 3000 g·cm 2 or less is preferable, 2950 g·cm 2 or less is more preferable, 2900 g·cm 2 or less is more preferable.

[0154] Regarding the above-described embodiments, the following appendices are disclosed. [Appendix 1] A face portion, a sole portion, an internal weight portion provided on the inner surface of the sole portion and spaced apart from the face portion, and having the internal weight portion includes a base portion and a protruding portion that protrudes from the base portion toward the face side while being spaced apart from the inner surface of the sole portion, the protruding portion is located on the face side of the head center of gravity, the protruding portion has a thickness of at least one of its toe side portion and heel side portion greater than the thickness of its central portion, or a golf club head in which the central portion in the toe-heel direction is missing. [Appendix 2] The golf club head according to Appendix 1, wherein the thickness of at least one of the toe side portion and the heel side portion of the protruding portion is greater than the thickness of the central portion. [Appendix 3] The golf club head according to Appendix 2, wherein the upper surface of the protruding portion in the central portion is located below the upper surface of at least one of the toe side portion and the heel side portion. [Appendix 4] The golf club head according to appendix 2 or 3, wherein in a cross-section along the toe-heel direction, the lower surface of the protruding portion is formed to follow the inner surface of the sole portion. [Appendix 5] The golf club head according to any one of appendices 1 to 4, wherein the lower surface of the protruding portion and the inner surface of the sole portion face each other so that an undercut is not formed. [Appendix 6] When the contact point on the face side between the internal weight portion and the inner surface of the sole portion is defined as the first contact point, and the thickness of the sole portion at the first contact point is defined as s1, the golf club head according to any one of appendices 1 to 5, wherein the thickness s1 is made smaller than the thickness of the front part of the sole located on the face side of the first contact point, so that a first thin portion is formed at the position of the first contact point. [Appendix 7] The golf club head according to appendix 6, wherein the sole portion has a thickness transition portion in the vicinity of the first contact point, and the thickness continuously decreases as it approaches the first contact point. [Appendix 8] The golf club head according to appendix 7, wherein the lower surface of the protruding portion and the upper surface of the thickness transition portion face each other so that an undercut is not formed.

Explanation of reference numerals

[0155] 100, 200, 300, 400 ··· Golf club head 100b, 200b, 300b, 400b ··· Body member 104, 204, 304, 404 ··· Face portion 108, 208, 308, 408 ··· Sole portion 108b, 208b, 308b, 408b ··· Inner surface of the sole portion 108c ··· Front part of the sole 108d ··· First thin portion 108e ··· Thickness transition portion 120, 220, 320, 420 ··· Internal weight portion 120T, 220T, 320T, 420T ··· Toe-side portion of the internal weight portion The central part of the internal weight part such as 120M, 220M, 320M, 420M··· The heel side part of the internal weight part such as 120H, 220H, 320H, 420H··· The base such as 122, 222, 322, 422··· The upper surface of the base such as 122a, 222a, 322a, 422a··· The toe base (the toe side part of the base) such as 122T, 222T, 322T, 422T··· The central base (the central part of the base) such as 122M, 222M, 322M, 422M·· The heel base (the heel side part of the base) such as 122H, 222H, 322H, 422H··· The protrusion such as 124, 224, 324, 424··· The upper surface of the protrusion such as 124a, 224a, 324a, 424a··· The lower surface of the protrusion such as 124b, 224b, 324b, 424b··· The toe protrusion (the toe side part of the protrusion) such as 124T, 224T, 324T, 424T··· The central protrusion (the central part of the protrusion) such as 124M, 324M, 424M·· The heel protrusion (the heel side part of the protrusion) such as 124H, 224H, 324H, 424H··· P1···The first contact point CG···The center of gravity of the head Fc···The face center SS···The sweet spot Le···The leading edge

Claims

1. a face portion, a sole portion, an internal weight portion provided on the inner surface of the sole portion and spaced apart from the face portion, and having, a recess that is open to the face side is formed by the internal weight portion and the sole portion, the internal weight portion includes a base portion and a protruding portion that protrudes from the base portion toward the face side while being spaced apart from the inner surface of the sole portion, the protruding portion is located on the face side of the head center of gravity, at least one of the toe side portion and the heel side portion of the protruding portion has a greater thickness than the thickness of the central portion thereof, when a contact point on the face side between the internal weight portion and the inner surface of the sole portion is defined as a first contact point and the thickness of the sole portion at the first contact point is defined as s1, a first thin portion is formed at the position of the first contact point by making the thickness s1 smaller than the thickness of the sole front portion located on the face side of the first contact point, the sole portion has a thickness transition portion in the vicinity of the first contact point, the thickness of which continuously decreases as it approaches the first contact point, a golf club head in which the distance between the lower surface of the protruding portion and the upper surface of the thickness transition portion continuously increases as it approaches the opening of the recess.

2. The golf club head according to claim 1, wherein the upper surface of the protruding portion in the central portion is located below the upper surface of at least one of the toe side portion and the heel side portion.

3. In a cross section along the toe-heel direction, when the distance between the lower surface of the protruding portion and the inner surface of the sole portion is defined as an opposing distance d1, the maximum value of the opposing distance d1 is defined as d1max, and the minimum value is defined as d1min, the golf club head according to claim 1 or 2, wherein at least one cross section in which [(d1max - d1min) / d1max] is 0.6 or less exists at a position in the face-back direction.

4. The golf club head according to any one of claims 1 to 3, wherein the distance between the lower surface of the protruding portion and the inner surface of the sole portion continuously increases as it approaches the opening of the recess.

5. The golf club head according to any one of claims 1 to 4, wherein the distance in the face-back direction from the most face-side point on the upper surface of the thickness transition portion to the first contact point is 3 mm or less. **Claim 6**: The golf club head according to any one of claims 1 to 5, wherein the width of the wall thickness transition portion in the face-back direction is 0.6 mm or more and 3 mm or less. **Claim 7**: The golf club head according to any one of claims 1 to 6, wherein the upper surface of the base portion and the upper surface of the protruding portion form a single plane, and this plane is inclined so as to be on the upper side as it approaches the face portion. **Claim 8**: The first thin-walled portion is formed in the toe-heel direction range where the central portion of the protruding portion exists. The first thin-walled portion is not formed in the toe-heel direction range where the toe-side portion of the protruding portion exists. **Claim 9**: The golf club head according to any one of claims 1 to 7, wherein in a longitudinal section including the head center of gravity, the back-side end of the internal weight portion is located on the back side of the head center of gravity. **Claim 10**: The golf club head according to any one of claims 1 to 8, wherein a portion where the upper surface of the base portion is inclined so as to become lower toward the back side extends to the back side of the head center of gravity. ​

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