Golf club head

Abstract

To make an improvement and an adjustment in a sound at impact in a golf club head that has a projection part or a recess part on a crown.SOLUTION: A hollow head 4 includes a face portion 10, a crown portion 12, a sole portion 14, and a hosel portion 16. The crown portion 12 forms a crown outer surface 12a and a crown inner surface 12b. The crown portion 12 includes a crown atypically-shaped portion 20 and a crown rib 30 that is provided on the crown inner surface 12b. The crown atypically-shaped portion 20 is a crown projection part that forms a projection part on the crown outer surface 12a while forming a recess part on the crown inner surface 12b, or a crown recess part that forms a recess part on the crown outer surface 12a while forming a projection part on the crown inner surface 12b. The crown rib 30 is arranged on a crown center side relative to a center C1 of the crown atypically-shaped portion 20.SELECTED DRAWING: Figure 11

Description

[Technical Field]

[0001] The present disclosure relates to golf club heads. [Background technology]

[0002] Golf club heads with crowns are known. Typically, the crown is formed entirely of a smoothly continuous convex curved surface. Japanese Patent Application Laid-Open Publication No. 2020-124360 discloses a golf club head with a step in the crown. This step lowers the rear portion of the head and contributes to lowering the center of gravity of the head. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-124360 Summary of the Invention [Problem to be solved by the invention]

[0004] The shape of the crown can affect the characteristics of the head. The inventors considered providing a convex or concave portion on the crown, which is normally a smoothly continuous convex curved surface. This convex or concave portion can affect, for example, the aerodynamic characteristics of the head. Furthermore, this convex or concave portion can affect, for example, the position of the center of gravity of the head. By providing a convex or concave portion on the crown, the degree of freedom in head design can be increased.

[0005] However, it was discovered that the convex and concave portions on the crown affect the impact sound. It was discovered that the convex and concave portions on the crown lower the impact sound and reduce the design freedom for the impact sound.

[0006] One object of the present disclosure is to provide a golf club head having a convex or concave portion on the crown, which allows for improvement and adjustment of the hitting sound. [Means for solving the problem]

[0007] In one aspect, the golf club head of the present disclosure is hollow. The golf club head has a face portion forming a striking face, a crown portion forming an outer crown surface and an inner crown surface, a sole portion forming an outer sole surface and an inner sole surface, and a hosel portion. The crown portion has a crown irregularity portion and a crown rib provided on the inner crown surface. The crown irregularity portion is a crown protrusion portion that forms a recess on the inner crown surface and a protrusion on the outer crown surface, or a crown recess portion that forms a protrusion on the inner crown surface and a recess on the outer crown surface. The crown rib is located toward the crown center relative to the center of the crown irregularity portion. [Effects of the Invention]

[0008] In one aspect, a golf club head can be provided that has a convex portion or a concave portion in the crown, allowing for improvement and adjustment of the hitting sound. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 shows a golf club equipped with a head according to the first embodiment. [Figure 2] Fig. 2 is a front view of the head of the first embodiment as seen from the face side, showing the head in a standard state. [Figure 3] FIG. 3 is a plan view of the head of the first embodiment as viewed from the crown side. [Figure 4] FIG. 4 is a perspective view of the head of the first embodiment as viewed from the heel back side. [Figure 5] FIG. 5 shows a cross-sectional view of the outer surface of the head taken along line AA in FIG. [Figure 6] FIG. 6 shows a cross-sectional view of the outer surface of the head taken along line BB in FIG. [Figure 7] FIG. 7 shows a cross-sectional view of the outer surface of the head taken along line CC in FIG. [Figure 8]FIG. 8 shows a cross-sectional view of the outer surface of the head taken along line DD in FIG. [Figure 9] Fig. 9 is an enlarged view of the part surrounded by the square line Q1 in Fig. 5. In Fig. 9, an imaginary extension line of the crown base surface is added. [Figure 10] Fig. 10 is an enlarged view of the part surrounded by the square line Q2 in Fig. 7. In Fig. 10, an imaginary extension line of the crown base surface is added. [Figure 11] FIG. 11 is the same plan view as FIG. [Figure 12] FIG. 12 is a cross-sectional view taken along the line AA in FIG. [Figure 13] 13(a) is an enlarged view of the circled area in FIG. 12, and FIG. 13(b) is a cross-sectional view taken along line BB in FIG. [Figure 14] FIG. 14 is a cross-sectional view taken along line CC in FIG. [Figure 15] FIG. 15 is a perspective view of the head body of the head according to the first embodiment. [Figure 16] FIG. 16 is a plan view of the head of the second embodiment. [Figure 17] FIG. 17 is a cross-sectional view taken along the line AA in FIG. [Figure 18] FIG. 18 is a cross-sectional view taken along line BB in FIG. [Figure 19] FIG. 19 is a perspective view of a head body of the head according to the second embodiment. [Figure 20] FIG. 20 is a plan view of the head of the third embodiment. [Figure 21] FIG. 21 is a cross-sectional view taken along the line AA in FIG. [Figure 22] FIG. 22 is a plan view of the head of the fourth embodiment. [Figure 23] FIG. 23 is a plan view of the head of the fifth embodiment. [Figure 24] FIG. 24 is a plan view of the head of the sixth embodiment. [Figure 25] FIG. 25 is a plan view of the head of the seventh embodiment. [Figure 26]FIG. 26 is a simulation image showing the primary vibration mode of the head in which the crown rib is removed from the head of the first embodiment. [Figure 27] FIG. 27 is a simulation image showing the primary vibration mode of the head in which the crown rib is removed from the head of the second embodiment. [Figure 28] FIG. 28 is a conceptual diagram for explaining the reference state. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, the present disclosure will be described in detail based on preferred embodiments, with appropriate reference to the drawings.

[0011] 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.

[0012] The state in which the head is placed on the ground plane HP at a predetermined lie angle is defined as the reference state. As shown in Figure 28, in this reference state, the shaft axis line Z is included in a plane VP perpendicular to the ground plane HP. The shaft axis line Z is the center line of the shaft. Typically, the shaft axis line Z coincides with the center line of the hosel hole. The plane VP is defined as the reference vertical plane. The predetermined lie angle is listed, for example, in a product catalog.

[0013] In this reference state, the face angle is set to 0 degrees. That is, in a plan view from above, the normal to the face center of the hitting face is set to be perpendicular to the toe-heel direction. The definitions of the face center and the toe-heel direction will be described later.

[0014] 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 HP (see FIG. 28).

[0015] In this application, the face-back direction is a direction perpendicular to the toe-heel direction and parallel to the ground plane HP. The face side in the face-back direction is also simply referred to as the "face side." The back side in the face-back direction is also simply referred to as the "back side."

[0016] 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 HP.

[0017] In the present application, the face center is determined as follows: First, an arbitrary point Pr is selected that is approximately near the center of the hitting face in the up-down direction and the toe-heel direction. Next, a plane is determined that passes through this point Pr, extends along the normal to the hitting face at point Pr, and is parallel to the toe-heel direction. A line of intersection between this plane and the hitting face is drawn, and its midpoint Px is determined. Next, a plane is determined that passes through this midpoint Px, extends along the normal to the hitting face at point Px, and is parallel to the up-down direction. A line of intersection between this plane and the hitting face is drawn, and its midpoint Py is determined. Next, a plane is determined that passes through this midpoint Py, extends along the normal to the hitting face at point Py, and is parallel to the toe-heel direction. A line of intersection between this plane and the hitting face is drawn, and its midpoint Px is newly determined. Next, a plane is determined that passes through this new midpoint Px, extends along the normal to the hitting face at point Px, and is parallel to the up-down direction. A line of intersection between this plane and the striking face is drawn, and its midpoint Py is newly determined. This process is repeated to sequentially determine Px and Py. During this process, the new position Py (last position Py) when the distance between the new midpoint Py and the previous midpoint Py is first 0.5 mm or less is the face center.

[0018] Fig. 1 is an overall view of a golf club 2 including a head 4 according to a first embodiment of the present disclosure. Fig. 2 is a front view of the head 4. Fig. 2 is a view of the head 4 in the standard state as seen from the face side. Fig. 3 is a plan view of the head 4 as seen from the crown side. Fig. 4 is a perspective view of the head 4 as seen from the heel back side.

[0019] 1, the golf club 2 includes a golf club head 4, a shaft 6, and a grip 8. The shaft 6 has a tip end Tp and a butt end Bt. The head 4 is attached to the tip end of the shaft 6. The grip 8 is attached to the butt end of the shaft 6.

[0020] The golf club 2 is a driver (number 1 wood). The head 4 is a driver head. Typically, the club length of a driver is 43 inches or more. Preferably, the golf club 2 is a wood-type golf club.

[0021] The shaft 6 is a tubular body. The shaft 6 has a hollow structure. The material of the shaft 6 is carbon fiber reinforced resin. From the viewpoint of weight reduction, carbon fiber reinforced resin is preferred as the material of the shaft 6. The shaft 6 is a so-called carbon shaft. Preferably, the shaft 6 is formed by curing a prepreg sheet. In this prepreg sheet, the fibers are oriented substantially in one direction. A prepreg in which the fibers are oriented substantially in one direction in this manner is also called a UD prepreg. "UD" stands for unidirectional. A prepreg other than a UD prepreg may also be used. For example, the fibers contained in the prepreg sheet may be woven. The shaft 6 may include metal wire. The material of the shaft 6 is not limited and may be, for example, metal.

[0022] The grip 8 is the part that is held by the golfer during a swing. Rubber compositions and resin compositions are examples of materials for the grip 8. The rubber composition of the grip 8 may contain air bubbles.

[0023] The head 4 has a hollow structure. In this embodiment, the head 4 is a wood type. The head 4 may be a hybrid type. The head 4 may be an iron type. The head 4 may be a putter type. Preferred materials for the head 4 include metal and fiber-reinforced plastic. Examples of the metal include titanium alloy, pure titanium, stainless steel, maraging steel, and mild steel. Examples of the fiber-reinforced plastic include carbon fiber-reinforced plastic. The head 4 may be a composite head having a metal portion and a fiber-reinforced plastic portion.

[0024] As shown in Figures 2 to 4, the head 4 has a face portion 10, a crown portion 12, a sole portion 14, and a hosel portion 16. The face portion 10 forms a hitting face 10a and a face inner surface (not shown). The hitting face 10a is the outer surface of the face portion 10. The hitting face 10a is also simply referred to as the face. The crown portion 12 forms a crown outer surface 12a and a crown inner surface 12b. The sole portion 14 forms a sole outer surface 14a and a sole inner surface 14b. The head 4 is hollow. That is, the head 4 has a hollow portion h1. The face inner surface, the crown inner surface 12b, and the sole inner surface 14b face the hollow portion h1 of the head 4. The crown inner surface 12b, the sole inner surface 14b, and the hollow portion h1 are shown in cross-sectional views of the head 4 (Figures 12 and 14), which will be described later.

[0025] The striking face 10a has a face center Fc defined above.

[0026] The crown portion 12 has a crown irregularity portion 20. The crown irregularity portion 20 is a portion that forms a hollow convex portion or a hollow concave portion. In this embodiment, the crown irregularity portion 20 is a crown convex portion 26 that forms a convex portion on the crown outer surface 12a and a concave portion on the crown inner surface 12b. Because the crown irregularity portion 20 forms a convex portion on the crown portion 12 in the external appearance of the head 4, it is also referred to as a crown convex portion 26.

[0027] In the front view (FIG. 2) of the head 4 seen from the face side, the irregular crown portion 20 is not visible. In the front view (FIG. 2) of the head 4 seen from the face side, the irregular crown portion 20 does not form the outer contour line CL1 of the head 4. The irregular crown portion 20 is a crown protrusion 26, which can raise the center of gravity of the head 4. While providing the crown protrusion 26 for aerodynamic characteristics, it is preferable to set the crown protrusion 26 at a low position from the viewpoint of not raising the center of gravity of the head. In such a case, the crown protrusion 26 can be provided at a position that is not visible in the front view of the head 4.

[0028] The entire crown irregularity portion 20 is provided in the crown portion 12. As shown in FIG. 3, the head 4 has an outer contour line CL2 in a plan view. The outer contour line CL2 includes a contour line CL4 of the crown portion 12 in a plan view. Except for the face portion 10 and the hosel portion 16, this outer contour line CL2 coincides with the contour line CL4. As shown in FIG. 3, the crown irregularity portion 20 does not reach the contour line CL4. The crown irregularity portion 20 does not extend to any portion other than the crown portion 12.

[0029] The contour line CL4 of the crown portion 12 includes a contour line CL5 on the face side. In a vertical cross section of the outer surface of the head 4, the radius of curvature of the vertical cross section line is confirmed from the center of the crown outer surface 12a toward the face portion 10, and the portion where this radius of curvature becomes 200 mm or less for the first time is identified. The point in this portion that is located closest to the center of the crown outer surface 12a can be determined to be the point that constitutes the contour line CL5. This point can be identified at each position in the toe-heel direction.

[0030] The plan view of the head 4 is a projection image of the head in the reference state projected onto a plane parallel to the ground plane HP. In the present application, the plan view of the head 4 (FIG. 3) is also referred to as a planar view.

[0031] In a plan view, the irregular crown portion 20 may reach the contour line CL4 of the crown portion 12. The irregular crown portion 20 may form part of the contour line CL4. The irregular crown portion 20 may extend to a portion other than the crown outer surface 12a. For example, the irregular crown portion 20 may extend from the crown portion 12 to the sole portion 14. If the head 4 has a side portion (skirt portion), the irregular crown portion 20 may extend from the crown portion 12 to the side portion.

[0032] The crown outer surface 12a includes a base surface b1. The portion of the crown outer surface 12a that does not have the irregular crown portion 20 is formed by the base surface b1. The base surface b1 is a smoothly continuous convex curved surface. This convex curved surface is a curved surface that is convex toward the outside of the head 4. As shown in FIG. 3, the base surface b1 belonging to the crown outer surface 12a includes the centroid EC of the plan view of the head 4. The centroid EC is the centroid of the figure formed by the outer contour line CL2.

[0033] The crown portion 12 includes a crown center RC. The crown center RC can be determined based on the centroid EC. As shown in FIG. 3, a cross-sectional line (vertical cross-sectional line) of the outer surface of the head 4 along a vertical cross-section V1 passing through the centroid EC defines a foremost point T1 of the head 4 and a topmost point T2 of the face surface 10a. The radius of curvature of the vertical cross-sectional line is confirmed from the center of the face surface 10a toward the crown portion 12, and a portion where this radius of curvature is 200 mm or less for the first time is identified. The point located closest to the center of the face surface 10a within this portion can be defined as the topmost point T2. The face-to-back distance between the foremost point T1 and the topmost point T2 is D1. In a plan view of the head 4, a point located half the distance D1 back from the centroid EC is defined as the crown center RC.

[0034] Fig. 5 shows the section line of the outer surface of the head 4 in a cross-sectional view taken along line AA in Fig. 3. Fig. 6 shows the section line of the outer surface of the head 4 in a cross-sectional view taken along line BB in Fig. 3. Fig. 7 shows the section line of the outer surface of the head 4 in a cross-sectional view taken along line CC in Fig. 3. Fig. 8 shows the section line of the outer surface of the head 4 in a cross-sectional view taken along line DD in Fig. 3. Figs. 5 to 8 include the section line of the crown outer surface 12a.

[0035] The irregular crown portion 20 has a contour line CL20, an upper surface 22, and a side wall surface 24 (see FIG. 3). The contour line CL20 is the contour line of the irregular crown portion 20 on the crown outer surface 12a. The contour line CL20 is the boundary line between the base surface b1 and the irregular crown portion 20. In a plan view, the contour line CL20 of the irregular crown portion 20 is a substantially quadrangle (substantially trapezoid) with four sides. In the present application, the term "substantially" includes a configuration in which the sides are curved (not straight) and a configuration in which the corners are rounded. Thus, in a plan view, the sides of the irregular crown portion 20 may be curved. In a plan view, the radius of curvature (allowable radius of curvature) of the sides is preferably 25 mm or more, more preferably 40 mm or more, and more preferably 50 mm or more. Of course, in a plan view, the sides may also be straight. If the side is curved, the first point of the portion where the radius of curvature is smaller than the allowable radius of curvature may be regarded as the end of the side. In plan view, the radius of curvature of the rounded corner is preferably 10 mm or less, more preferably 7 mm or less, and even more preferably 5 mm or less. The contour line CL20 forms a substantially rectangular shape.

[0036] Note that there may be sides that are not visible in plan view, such as the third side 63 (FIG. 16) of the head 50 described below. Even in this case, the side can be recognized in plan view by the hidden line (perspective line) of the side.

[0037] The top surface 22 and the sidewall surface 24 may be separated by a ridgeline. In a cross-sectional line of the outer surface of the crown profile 20, this ridgeline may be identified as a point or a bend apex having a radius of curvature of 5 mm or less. The radius of curvature of this cross-sectional line may vary depending on the direction of the cross-section, but in determining the radius of curvature to define the ridgeline, a cross-section that minimizes the radius of curvature is selected.

[0038] As will be described later, it is preferable that the crown irregularity portion 20 has at least one side. That is, it is preferable that the contour line CL20 has at least one side on the crown outer surface 12a. As in this embodiment, the crown irregularity portion 20 (contour line CL20) may be an approximately polygonal shape. When this approximately polygonal shape is an approximately N-sided polygon, N may be an integer of 3 or more. N may also be an integer of 3 or more and 20 or less.

[0039] As shown in Figure 3, the irregular crown portion 20 (contour line CL20) has a first side CL21, a second side CL22, a third side CL23, and a fourth side CL24. The first side CL21 constitutes the side on the toe side and face side of the irregular crown portion 20. The first side CL21 extends toward the back side as it approaches the toe side. The first side CL21 connects the second side CL22 and the fourth side CL24.

[0040] The second side CL22 constitutes the side on the heel side and face side of the irregularly shaped crown portion 20. The second side CL22 extends toward the back side as it approaches the heel side. The second side CL22 connects the first side CL21 and the third side CL23.

[0041] The third side CL23 constitutes the heel-side and back-side side of the irregular crown portion 20. The third side CL23 extends toward the toe side and then toward the back side. The third side CL23 connects the second side CL22 and the fourth side CL24. The third side CL23 is a curved line that convexly extends toward the outside of the head 4.

[0042] The fourth side CL24 constitutes the toe-side and back-side side of the crown irregularly shaped portion 20. The fourth side CL24 extends toward the back side as it approaches the heel side. The fourth side CL24 connects the third side CL23 and the first side CL21.

[0043] The second side CL22, the third side CL23, and the fourth side CL24 each serve as a base point of the side wall surface 24. That is, the second side CL22, the third side CL23, and the fourth side CL24 each form a boundary line between the side wall surface 24 and the base surface b1. On the other hand, the first side CL21 does not serve as a base point of the side wall surface 24. The first side CL21 forms a boundary line between the base surface b1 and the top surface 22.

[0044] In the present application, a cross-sectional line in a cross section along the toe-heel direction is also simply referred to as a transverse cross-sectional line. FIG. 5 is an example of a transverse cross-sectional line. A transverse cross-sectional line on the outer surface of the head 4 is also simply referred to as a transverse cross-sectional line. In the present application, a cross-sectional line in a cross section along the face-back direction is also simply referred to as a longitudinal cross-sectional line. FIG. 7 is an example of a longitudinal cross-sectional line. A longitudinal cross-sectional line on the outer surface of the head 4 is also simply referred to as a longitudinal cross-sectional line.

[0045] The inflection point on the cross section line can be a point that constitutes the contour line CL20. In other words, this inflection point can be the starting point of the irregular crown portion 20. The cross section line of the base surface b1 is a curve that is convex toward the outside of the head 4. The inflection point is a point where the curve that is convex toward the outside of the head 4 changes into a curve that is convex toward the inside of the head 4.

[0046] The vertex of the bend in the cross-sectional line can be a point that constitutes the contour line CL20. In other words, this vertex can be the starting point of the crown irregularity portion 20. The cross-sectional line of the base surface b1 is a convex curve that extends outward from the head 4. The line that connects to this curve and bends upward forms a vertex. This vertex faces inward from the head 4. This vertex can be the starting point of the crown irregularity portion 20.

[0047] The inflection point on the longitudinal section line can be a point that constitutes the contour line CL20. In other words, this inflection point can be the starting point of the irregular crown portion 20. The longitudinal section line of the base surface b1 is a curve that is convex toward the outside of the head 4. The inflection point is a point where the curve that is convex toward the outside of the head 4 changes into a curve that is convex toward the inside of the head 4.

[0048] The apex of the bend in the longitudinal section line can be a point that constitutes the contour line CL20. In other words, this apex can be the starting point of the crown irregularity portion 20. The longitudinal section line of the base surface b1 is a curve that convexly extends outward from the head 4. The line that connects to this curve and bends upward forms a apex. This apex faces inward from the head 4. This apex can be the starting point of the crown irregularity portion 20.

[0049] Typically, the contour line CL20 can be determined by the inflection point or the apex. In selecting the cross-sectional line for this determination, the transverse cross-sectional line may be prioritized over the longitudinal cross-sectional line. In this case, the transverse cross-sectional line is used to identify the inflection point or the apex. If it is difficult to identify the inflection point or the apex using the transverse cross-sectional line, the longitudinal cross-sectional line can be used. The clearly visible contour line of the crown irregular-shaped portion 20 can be considered as the contour line CL20.

[0050] The crown irregularity portion 20 is a portion that protrudes from the base surface b1. An imaginary extension surface b2, which is an extension of the base surface b1, can be identified below the crown irregularity portion 20. The crown irregularity portion 20 is a portion that protrudes from the imaginary extension surface b2. The imaginary extension surface b2 can be considered to be the base surface b1 that would be formed in the installation area of ​​the crown irregularity portion 20 if the crown irregularity portion 20 were not present. The imaginary extension surface b2 is formed continuously with the base surface b1. The imaginary extension surface b2 is a curved surface that is convex toward the outside of the head 4. The imaginary extension surface b2 is smoothly connected to the base surface b1.

[0051] Fig. 9 is an enlarged view of a portion surrounded by a square line Q1 in Fig. 5. Fig. 10 is an enlarged view of a portion surrounded by a square line Q2 in Fig. 7.

[0052] The cross-sectional line in FIG. 9 has an imaginary extension line b3 drawn thereon, which can constitute the imaginary extension surface b2. The imaginary extension line b3 is a curved line that convexly extends outward from the head 4. The imaginary extension line b3 smoothly connects to the cross-sectional line of the base surface b1. The imaginary extension surface b2 can be formed by a collection of imaginary extension lines b3.

[0053] The imaginary extension line b3 smoothly connects the cross-sectional line of the base surface b1 on one side of the crown irregular-shaped portion 20 with the cross-sectional line of the base surface b1 on the other side of the crown irregular-shaped portion 20. The imaginary extension line b3 can be drawn as a Bezier curve. Known Bezier curves include quadratic Bezier curves and cubic Bezier curves. A quadratic Bezier curve has one control point. A cubic Bezier curve has two control points. Preferably, a cubic Bezier curve is used. The Bezier curves in Figures 9 and 10 are cubic Bezier curves.

[0054] 9, the cross-sectional line has a first starting point P1 and a second starting point P2. The first starting point P1 and the second starting point P2 are points on the contour line CL20.

[0055] To define the effective tangent at the first starting point P1, points P11 and P12 are set on the opposite side of the first starting point P1 from the crown profile 20. Point P11 is 0.5 mm away from the first starting point P1. Point P12 is 0.5 mm away from point P11. These 0.5 mm distances are the distance along the cross-sectional line. Points P11 and P12 are points on the cross-sectional line. A tangent line L1 at point P1 to a circle that passes through the three points P1, P11, and P12 is determined. If points P1, P11, and P12 are on the same line, this line can be taken as the tangent line L1.

[0056] Similarly, to define the effective tangent at the second starting point P2, points P21 and P22 are set on the opposite side of the second starting point P2 from the crown profile 20. Point P21 is 0.5 mm away from the second starting point P2. Point P22 is 0.5 mm away from point P21. These 0.5 mm distances are the distance along the cross-sectional line. Points P21 and P22 are points on the cross-sectional line. A tangent line L2 at point P2 to a circle passing through the three points P2, P21, and P22 is determined. If points P2, P21, and P22 are on the same line, this line can be taken as the tangent line L2.

[0057] Once the tangent line L1 and the tangent line L2 are determined, the intersection point Px of the tangent line L1 and the tangent line L2 is determined. Furthermore, the midpoint M1 between the point P1 and the point Px is determined, and the midpoint M2 between the point P2 and the point Px is determined.

[0058] A Bezier curve can be drawn with point P1 as the start point, midpoint M1 as the first control point, midpoint M2 as the second control point, and point P2 as the end point. In Figure 9, this Bezier curve is the virtual extension line b3. Since there are two control points, this Bezier curve is a cubic Bezier curve.

[0059] An imaginary extension line b3 can be defined at any position in the face-back direction. A set of these imaginary extension lines b3 can define an imaginary extension plane b2.

[0060] A similar Bezier curve can be defined for a vertical section line. As shown in Fig. 10, the vertical section line has a first starting point P1 and a second starting point P2. The first starting point P1 and the second starting point P2 are points on the contour line CL20.

[0061] To define the effective tangent at the first starting point P1, points P11 and P12 are set on the opposite side of the first starting point P1 from the crown profile portion 20. Point P11 is 0.5 mm away from the first starting point P1. Point P12 is 0.5 mm away from point P11. These 0.5 mm distances are the distances along the longitudinal section line. Points P11 and P12 are points on the longitudinal section line. A tangent line L1 at point P1 to a circle that passes through the three points P1, P11, and P12 is determined. If points P1, P11, and P12 are on the same line, this line can be taken as the tangent line L1.

[0062] Similarly, to define the effective tangent at the second starting point P2, points P21 and P22 are determined on the opposite side of the second starting point P2 from the crown profile portion 20. Point P21 is 0.5 mm away from the second starting point P2. Point P22 is 0.5 mm away from point P21. These 0.5 mm distances are the distances along the longitudinal section line. Points P21 and P22 are points on the longitudinal section line. A tangent line L2 at point P2 to a circle passing through the three points P2, P21, and P22 is determined. If points P2, P21, and P22 are on the same line, this line can be taken as the tangent line L2.

[0063] Once the tangent line L1 and the tangent line L2 are determined, the intersection point Px of the tangent line L1 and the tangent line L2 is determined. Furthermore, the midpoint M1 between the point P1 and the point Px is determined, and the midpoint M2 between the point P2 and the point Px is determined.

[0064] A Bezier curve can be drawn with point P1 as the start point, midpoint M1 as the first control point, midpoint M2 as the second control point, and point P2 as the end point. In Figure 10, this Bezier curve is the virtual extension line b4.

[0065] An imaginary extension line b4 can be defined at any position in the toe-heel direction. A set of these imaginary extension lines b4 can define an imaginary extension plane b2.

[0066] In some cases, the irregular crown portion may reach the outer peripheral edge (contour line CL4) of the crown portion. In this case, the irregular crown portion formed at the boundary between the irregular crown portion and the base surface b1 may have only one starting point on the cross-sectional line and / or the longitudinal-sectional line. When there is only one starting point, the imaginary extension line b3 may be an arc along the radius of curvature of the starting point. In other words, in this case, the imaginary extension line b3 may be a circle passing through three points: the first point, which is the starting point; a second point 0.5 mm away from the first point; and a third point 0.5 mm away from the second point.

[0067] In determining the imaginary extension plane b2, the transverse section lines may be used in preference to the longitudinal section lines. The imaginary extension plane b2 may be determined by a set of imaginary extension lines b3 based on the transverse section lines. If the set of imaginary extension lines b3 is unclear, the imaginary extension plane b2 may be determined by a set of imaginary extension lines b4 based on the longitudinal section lines.

[0068] The height Ht of the crown irregularity portion 20 can be defined as the height from the imaginary extension plane b2. As shown in FIG. 9, the normal LN of the imaginary extension plane b2 at a certain point f1 intersects with the outer surface of the crown irregularity portion 20 at a point f2, f2. The distance from point f1 to the intersection f2 can be defined as the height Ht of the crown irregularity portion 20 at the intersection f2. Note that if the crown irregularity portion has a point that does not intersect with the normal LN of the imaginary extension plane b2 but intersects with the normal to the base plane b1, the height Ht of that point is defined as the height from the base plane b1. In this case, the length of the normal is also the height Ht. Even if the crown irregularity portion 20 forms a recess in the crown outer surface 12a, the height Ht of the crown irregularity portion 20 is also the height from the imaginary extension plane b2. In this case, the intersection f2 is the intersection with the inner surface of the crown irregularity portion 20. The maximum value of the height Ht is the maximum height of the crown irregularity portion 20.

[0069] As described above, when the irregular crown portion 20 is a crown protrusion 26 that forms a protrusion on the crown outer surface 12a, the imaginary extension surface b2 and the contour line CL20 can be determined. When the irregular crown portion 20 is a crown recess that forms a recess on the crown outer surface 12a, the imaginary extension surface b2 and the contour line CL20 can be determined in a similar manner. In the case of this crown recess, the contour line CL20 of the irregular crown portion 20 can be determined on the crown outer surface 12a. However, in this case, the points constituting the contour line CL20, including the points P1 and P2, are not inflection points on the cross-sectional line of the crown outer surface 12a. This is because, when a recess is formed on the crown outer surface 12a, the roundness of the starting point of the recess is a convex curve extending outward from the head 4, similar to the base surface b1. From this perspective, when the irregular crown portion 20 is a crown recess, the points constituting the contour line CL20 can be determined as the minimum radius of curvature or the vertex of the bend on the cross-sectional line. When the portion with the minimum radius of curvature is an arc, the midpoint of the arc can be set as a point that forms the contour line CL20. Except for this point, the method for determining the contour line CL20 and the imaginary extended surface b2 in the crown recessed portion is the same as the method for determining the contour line CL20 and the imaginary extended surface b2 in the crown protruding portion.

[0070] FIG. 11 is a plan view of the head 4, the same as FIG. 3. In FIG. 11, the crown rib 30 and the sole rib 40 provided on the inner surface of the head 4 are indicated by dashed lines. The crown rib 30 and the sole rib 40 are simply indicated by rib center lines L30, L40. FIG. 12 is a cross-sectional view taken along line AA in FIG. 11. FIG. 13(a) is an enlarged view of the circled area in FIG. 12. FIG. 13(b) is a cross-sectional view taken along line BB in FIG. 11. FIG. 14 is a cross-sectional view taken along line CC in FIG. 11. FIG. 15 is a perspective view of the head main body 4a of the head 4. In the head 4, a face member (not shown) and the head main body 4a are joined (welded). The interior of the head 4 is visible in FIG. 14.

[0071] As shown in Figures 12 and 13(a), the irregular crown portion 20 forms a recess 20b on the crown inner surface 12b and a protrusion 20a on the crown outer surface 12a. The recess 20b is also referred to as an inner surface recess. The protrusion 20a is also referred to as an outer surface protrusion. The inner surface recess 20b is recessed corresponding to the outer surface protrusion 20a. As shown in Figure 13(a), the inner surface recess 20b has a portion located outside the imaginary extension plane b2 (outside the head 4).

[0072] A bent portion 28 is formed in the crown portion 12 along the contour line CL20 of the irregular crown portion 20. The bent portion 28 is formed by bending the wall that constitutes the crown portion 12. The bent portion 28 may be folded or curved. On the crown outer surface 12a, the contour line CL20 is the starting point of the bend in the bent portion 28. The thickness of the irregular crown portion 20 is approximately the same as the thickness of the crown portion 12 around the irregular crown portion 20. The bent portion 28 is formed because an inner surface recess 20b is formed on the back side of the outer surface protrusion 20a. In the embodiment of FIG. 13(a), the bent portion 28 forms a rounded portion on the crown outer surface 12a and a bent portion on the crown inner surface 12b. The bent portion 28 may be rounded on both the crown outer surface 12a and the crown inner surface 12b. The bent portion 28 may form a bend on the crown outer surface 12a and the crown inner surface 12b. The bent portion 28 may form a bend on the crown outer surface 12a and a radius on the crown inner surface 12b.

[0073] As shown by the dashed lines in Fig. 11, the crown portion 12 has a rib 30. The rib 30 is provided on the crown inner surface 12b. The rib 30 is also referred to as a crown rib. The crown portion 12 including the crown rib 30 is integrally molded.

[0074] The crown rib 30 is provided at a position different from the crown irregular-shaped portion 20. The crown rib 30 is spaced apart from the crown irregular-shaped portion 20. The crown rib 30 does not intersect with the crown irregular-shaped portion 20. The crown rib 30 may intersect with the crown irregular-shaped portion 20.

[0075] In this embodiment, there is one crown rib 30. However, there may be a plurality of crown ribs 30.

[0076] As shown by the dashed lines in FIG. 11, the sole portion 14 is provided with a rib 40. As shown in FIG. 12, the rib 40 is provided on the sole inner surface 14b. The rib 40 is also referred to as a sole rib. The sole rib 40 has a first sole rib 42 and a second sole rib 44. The first sole rib 42 and the second sole rib 44 intersect with each other. The sole rib 40 may be one, or may be multiple as in this embodiment.

[0077] 11, the crown rib 30 is disposed closer to the crown center than the center C1 of the irregular crown portion 20. That is, in plan view, a line segment S1 connecting the center C1 and the crown center RC intersects with the crown rib 30. The center C1 of the irregular crown portion 20 is the centroid of the contour line CL20 in plan view.

[0078] The crown rib 30 is disposed on the crown center side relative to the entire irregular crown portion 20. That is, in plan view, the crown rib 30 is disposed between the contour line CL20 of the irregular crown portion 20 and the crown center RC. In plan view, the crown rib 30 intersects with the line segment S1 connecting the center C1 and the crown center RC, but does not intersect with the irregular crown portion 20.

[0079] The contour line CL20 of the irregular crown portion 20 has at least one side. As described above, in this embodiment, the contour line CL20 has four sides CL21 to CL24. These sides CL21 to CL24 include a specific side CL24 that is located on the crown center side with respect to the center C1 of the irregular crown portion 20. In a plan view, the side that intersects with the line segment S1 is the specific side.

[0080] FIG. 13(b) is a cross-sectional view taken along line BB in FIG. 11. This line BB is aligned along the width direction of the crown rib 30. The crown rib 30 has a first starting point 30a and a second starting point 30b. A line segment S2 is determined connecting the first starting point 30a and the second starting point 30b. The length of line segment S2 is the rib base width W1. The width direction is the direction in which the rib base width W1 is smallest. In the cross section taken along the width direction, a midpoint Pm of line segment S2 is determined. The set of these midpoints Pm is the rib center line L30.

[0081] In Figure 13(b), the double-headed arrow Hr indicates the height of the crown rib 30. The height Hr is measured in a cross section along the width direction. The height Hr is measured along a direction perpendicular to the line segment S2. The height Hr is the height from the line segment S2.

[0082] The crown rib 30 is substantially parallel to the specific side CL24. That is, in a plan view, the angle formed between the rib center line L30 of the crown rib 30 and the specific side CL24 is 0°±10°. In other words, this angle is between -10° and +10°. When determining this angle, if the rib center line L30 is a curve, tangents at each point on this curve are taken into consideration. Similarly, when determining this angle, if the specific side CL24 is a curve, tangents at each point on this curve are taken into consideration. When the angle of 0°±10° is established for all tangents, the crown rib 30 and the specific side CL24 are substantially parallel. More preferably, in a plan view, the angle formed between the rib center line L30 and the specific side CL24 is 0°±7°. More preferably, in a plan view, the angle formed between the rib center line L30 and the specific side CL24 is 0°±5°.

[0083] At least one end of the crown rib 30 is located at the outer edge 12e of the crown portion 12. In a plan view, the outer edge 12e is a region of the crown portion 12 that is 10 mm or less away from the contour line CL4 (shortest distance). This outer edge 12e includes an outer edge 12f that is 10 mm or less away from the contour line CL5 of the face side of the crown portion 12 (shortest distance). As shown in FIG. 11 , the crown rib 30 has a back-side end 30b and a face-side end 30f. In this embodiment, only one of the two ends of the crown rib 30 is located at the outer edge 12e. In this embodiment, the back-side end 30b is located at the outer edge 12e. On the other hand, the face-side end 30f is not located at the outer edge 12e. The face-side end 30f is located closer to the back side than the outer edge 12f.

[0084] In the head 4, the entire irregular crown portion 20 is disposed in an area 40 mm or less from the contour line CL4 of the crown portion 12. That is, in a plan view, the distance (shortest distance) from any point on the contour line CL20 of the irregular crown portion 20 to the contour line CL4 is 40 mm or less.

[0085] Fig. 16 is a plan view of the head 50 of the second embodiment, Fig. 17 is a cross-sectional view taken along line AA in Fig. 16, and Fig. 18 is a cross-sectional view taken along line BB in Fig. 16. Fig. 19 is a perspective view of the head body 50a of the head 50. In the head 50, a face member (not shown) and the head body 50a are joined (welded). In Fig. 19, the inside of the head 50 is visible because the face member is not shown.

[0086] The head 50 has a face portion 10, a crown portion 12, a sole portion 14, and a hosel portion 16. The face portion 10 has a hitting face 10a. The hitting face 10a is the outer surface of the face portion 10. The crown portion 12 forms a crown outer surface 12a and a crown inner surface 12b. The crown outer surface 12a includes a crown base surface b1, which is a continuous convex curved surface without any steps. The sole portion 14 forms a sole outer surface 14a and a sole inner surface 14b. The hosel portion 16 has a shaft hole 16a.

[0087] The crown portion 12 has a crown irregularity portion 60. The crown irregularity portion 60 is hollow. The crown irregularity portion 60 forms an inner surface recess 60b on the crown inner surface 12b, and an outer surface protrusion 60a on the crown outer surface 12a. The inner surface recess 60b is recessed corresponding to the outer surface protrusion 60a. The crown irregularity portion 60 forms a protrusion on the crown portion 12 in the external appearance of the head 50. The crown irregularity portion 60 is a crown protrusion 62. The entire crown irregularity portion 60 is located on the heel side of the face center.

[0088] The irregular crown portion 60 has a contour line CL60. The contour line CL60 is a boundary line between the crown base surface b1 and the irregular crown portion 60. In a plan view (plan view) of the head 50, the irregular crown portion 60 is substantially pentagonal. The approximate pentagon is formed by the contour line CL60.

[0089] The contour line CL60 of the crown irregular-shaped portion 60 has a first side CL61, a second side CL62, a third side CL63, a fourth side CL64, and a fifth side CL65.

[0090] 17 and 18, a curved portion 64 is formed in the crown portion 12 along the contour line CL60 of the irregular crown portion 60. The thickness of the irregular crown portion 60 is approximately the same as the thickness of the crown portion 12 around the irregular crown portion 60. The curved portion 64 is formed as a result of an inner surface recess 60b being formed on the back side of the outer surface protrusion 60a.

[0091] As shown by the dashed line in Fig. 16, the crown portion 12 has a rib (crown rib) 70. The crown rib 70 is simply indicated by a rib center line L70. The crown rib 70 is provided on the crown inner surface 12b. The crown portion 12 including the crown rib 70 is integrally molded.

[0092] The crown rib 70 is provided at a position different from the crown irregular-shaped portion 60. The crown rib 70 is spaced apart from the crown irregular-shaped portion 60. The crown rib 70 does not intersect with the crown irregular-shaped portion 60.

[0093] As shown by the dashed line in FIG. 16 , the sole portion 14 of the head 50 has a rib 80. The rib 80 is provided on the sole inner surface 14b. The rib 80 is also referred to as a sole rib. The sole rib 80 is simply indicated by a rib center line L80. The sole rib 80 has a first sole rib 82 and a second sole rib 84. The first sole rib 82 and the second sole rib 84 intersect with each other.

[0094] As shown in FIG. 16 , the crown rib 70 is positioned closer to the crown center than the center C1 of the irregular crown portion 60. Furthermore, the crown rib 70 is positioned closer to the crown center than the entire irregular crown portion 60. The contour line CL60 of the irregular crown portion 60 includes a specific side CL65 located closer to the crown center than the center C1 of the irregular crown portion 60. The crown rib 70 is substantially parallel to the specific side CL65. A first end (back-side end) 70b of the crown rib 70 is located on the outer edge 12e of the crown portion 12. A second end (face-side end) 70f of the crown rib 70 is not located on the outer edge 12e. The face-side end 70f is located closer to the back than the outer edge 12f. In the head 50, the entire irregular crown portion 60 is positioned within 40 mm of the contour line CL4 of the crown portion 12.

[0095] FIG. 20 is a plan view of a head 90 according to the third embodiment, and FIG. 21 is a cross-sectional view taken along line AA in FIG.

[0096] The head 90 has a face portion 10, a crown portion 12, a sole portion 14, and a hosel portion 16. The face portion 10 has a hitting face 10a. The hitting face 10a is the outer surface of the face portion 10. The crown portion 12 forms a crown outer surface 12a and a crown inner surface 12b. The crown outer surface 12a includes a crown base surface b1, which is a continuous convex curved surface without any steps. The sole portion 14 forms a sole outer surface 14a and a sole inner surface 14b. The hosel portion 16 has a shaft hole 16a. The crown inner surface 12b and the sole inner surface 14b face the hollow portion k1.

[0097] The crown portion 12 has a crown irregularity portion 100. The crown irregularity portion 100 is hollow. Unlike the previously described crown irregularity portion 20 and crown irregularity portion 60, the crown irregularity portion 100 is a crown recess 102. The crown irregularity portion 100 forms a convex portion (inner surface convex portion) 100b on the crown inner surface 12b, and a recess (outer surface recess) 100a on the crown outer surface 12a. The inner surface convex portion 100b protrudes corresponding to the outer surface recess 100a. The crown irregularity portion 100 forms a recess in the crown portion 12 in the external appearance of the head 90. The entire crown irregularity portion 100 is located on the heel side of the face center. Except for the shape of the crown irregularity portion, the head 90 is the same as the head 50.

[0098] The outer surface recess 100a has a portion located inside the imaginary extension plane b2 (inside the head 90).

[0099] The crown recess 102 can be used as an attachment portion for attaching an additional component such as a badge. The additional component such as a badge can be attached to the outer surface recess 100a. Physical engagement by the outer surface recess 100a enhances the fixation of the additional component. Providing a flat portion on the bottom surface of the outer surface protrusion 100a can improve attachment (adhesion). In addition, the outer surface recess 100a can reduce the protrusion height of the additional component from the crown outer surface 12a. The material of the additional component such as a badge can be resin, metal, ceramic, or a combination thereof.

[0100] The irregular crown portion 100 has a contour line CL100. In a plan view, the irregular crown portion 100 is substantially rectangular. The substantially rectangular shape is formed by the contour line CL100.

[0101] The crown irregular-shaped portion 100 (contour line CL100) has a first side CL101, a second side CL102, a third side CL103, and a fourth side CL104.

[0102] 21, a curved portion 104 is formed in the crown portion 12 along the contour line CL100 of the irregular crown portion 100. The thickness of the irregular crown portion 100 is approximately the same as the thickness of the crown portion 12 around the irregular crown portion 100. The curved portion 104 is formed as a result of an inner surface convex portion 100b being formed on the back side of the outer surface concave portion 100a.

[0103] As shown by the dashed line in Figure 20, the crown portion 12 has a rib (crown rib) 110. The crown rib 110 is simply indicated by a rib center line L110. The crown rib 110 is provided on the crown inner surface 12b. The crown portion 12 including the crown rib 110 is integrally molded.

[0104] The crown rib 110 is provided at a position different from the crown irregular-shaped portion 100. The crown rib 110 is spaced apart from the crown irregular-shaped portion 100. The crown rib 110 does not intersect with the crown irregular-shaped portion 100. The crown rib 110 is located between the crown irregular-shaped portion 100 and the crown center RC.

[0105] As shown by the dashed line in Figure 20, the sole portion 14 of the head 90 has a rib (sole rib) 120. The sole rib 120 is simply indicated by a rib center line L120. The rib (sole rib) 120 is provided on the sole inner surface 14b. The sole rib 120 has a first sole rib 122 and a second sole rib 124. The first sole rib 122 and the second sole rib 124 intersect with each other.

[0106] As shown in FIG. 20 , the crown rib 110 is located closer to the crown center than the center C1 of the irregular crown portion 100. The crown rib 110 is located closer to the crown center than the entire irregular crown portion 100. The contour line CL100 of the irregular crown portion 100 includes a specific side CL104 located closer to the crown center than the center C1 of the irregular crown portion 100. The crown rib 110 is substantially parallel to the specific side CL104. A first end (back-side end) 110b of the crown rib 110 is located on the outer edge 12e of the crown portion 12. A second end (face-side end) 110f of the crown rib 110 is not located on the outer edge 12e. The face-side end 110f is located closer to the back than the outer edge 12f. In the head 90, the entire irregular crown portion 100 is located within 40 mm of the contour line CL4 of the crown portion 12.

[0107] 22 is a plan view of a head 130 of the fourth embodiment. Except for the crown irregularity portion and the crown rib, the head 120 is the same as the head 4 described above. The head 130 has a face portion 10, a crown portion 12, a sole portion (not shown), and a hosel portion 16.

[0108] The crown portion 12 has a crown irregularity portion 140. The crown irregularity portion 140 is a crown protrusion portion 142. The crown irregularity portion 140 has a contour line CL140. The contour line CL140 includes multiple (four) sides. The contour line CL140 has a first side CL141, a second side CL142, a third side CL143, and a fourth side CL144. The contour line CL140 has a specific side CL144 that is located on the crown center side with respect to the center of the crown irregularity portion 140.

[0109] The crown portion 12 has a crown rib 150. The crown rib 150 is provided on the inner surface of the crown portion 12. The crown rib 150 is simply indicated by a dashed line indicating its rib center line L150. The crown rib 150 is provided at a position different from the crown irregularity portion 140. The crown rib 150 is spaced apart from the crown irregularity portion 140. The crown rib 150 does not intersect with the crown irregularity portion 140. The crown rib 150 is located between the crown irregularity portion 140 and the crown center RC.

[0110] The crown rib 150 is disposed on the crown center side relative to the center of the crown irregular-shaped portion 140. The crown rib 150 is disposed on the crown center side relative to the entire crown irregular-shaped portion 140. The crown rib 150 is substantially parallel to the specific side CL144. A first end 150b of the crown rib 150 is located on the outer edge 12e of the crown portion 12. A second end 150f of the crown rib 150 is not located on the outer edge 12e. In the head 130, the entire crown irregular-shaped portion 140 is disposed in an area 40 mm or less from the contour line CL4 of the crown portion 12.

[0111] 23 is a plan view of a head 160 of the fifth embodiment. Except for the crown irregularity portion and the crown rib, the head 160 is the same as the head 4 described above. The head 160 has a face portion 10, a crown portion 12, a sole portion (not shown), and a hosel portion 16.

[0112] The crown portion 12 has a crown irregularity portion 170. The crown irregularity portion 170 is a crown protrusion 172. The crown irregularity portion 170 has a contour line CL170. The contour line CL170 includes multiple (four) sides. The contour line CL170 has a specific side CL171 that is located on the crown center side with respect to the center of the crown irregularity portion 170.

[0113] The crown portion 12 has a crown rib 180. The crown rib 180 is provided on the inner surface of the crown portion 12. The crown rib 180 is simply indicated by a dashed line indicating its rib center line L180. The crown rib 180 includes a portion located on the inner surface of the crown irregularity portion 170. In other words, the crown rib 180 intersects with the crown irregularity portion 170. The crown rib 180 intersects with a specific side CL171. The crown rib 180 is located between the center of the crown irregularity portion 170 and the crown center RC.

[0114] The crown rib 180 is disposed on the crown center side relative to the center of the crown irregularity portion 170. However, the crown rib 180 is not disposed on the crown center side relative to the entire crown irregularity portion 170. The crown rib 180 is not substantially parallel to the specific side CL171. A first end 180b of the crown rib 180 is located on the outer edge 12e of the crown portion 12. A second end 180f of the crown rib 180 is not located on the outer edge 12e. In the head 160, the entire crown irregularity portion 170 is disposed in an area 40 mm or less from the contour line CL4 of the crown portion 12.

[0115] 24 is a plan view of a head 190 of the sixth embodiment. Except for the crown irregularity portion and the crown rib, the head 190 is the same as the head 4 described above. The head 190 has a face portion 10, a crown portion 12, a sole portion (not shown), and a hosel portion 16.

[0116] The crown portion 12 has a crown irregularity portion 200. The crown irregularity portion 200 is a crown protrusion 202. The crown irregularity portion 200 has a contour line CL200. The contour line CL200 has a specific side CL201.

[0117] The crown portion 12 has a crown rib 210. The crown rib 210 is provided on the inner surface of the crown portion 12. The crown rib 210 is simply indicated by a dashed line indicating its rib center line L210. The crown rib 210 is provided at a position different from the crown irregular-shaped portion 200. The crown rib 210 is spaced apart from the crown irregular-shaped portion 200. The crown rib 210 does not intersect with the crown irregular-shaped portion 200. The crown rib 210 is located between the crown irregular-shaped portion 200 and the crown center RC.

[0118] The crown rib 210 is disposed on the crown center side relative to the center of the irregular crown portion 200. The crown rib 210 is disposed on the crown center side relative to the entire irregular crown portion 200. A first end 210b of the crown rib 210 is not located on the outer edge 12e of the crown portion 12. A second end 210f of the crown rib 210 is also not located on the outer edge 12e. In the head 190, the entire irregular crown portion 200 is disposed in an area 40 mm or less from the contour line CL4 of the crown portion 12.

[0119] 25 is a plan view of a head 220 of the seventh embodiment. Except for the crown irregularity portion and the crown rib, the head 220 is the same as the head 4 described above. The head 220 has a face portion 10, a crown portion 12, a sole portion (not shown), and a hosel portion 16.

[0120] The crown portion 12 has a plurality of (two) crown irregularity portions. The crown portion 12 has a first crown irregularity portion 230 and a second crown irregularity portion 240. The crown irregularity portion 230 is a crown protrusion portion 232. The crown irregularity portion 240 is a crown protrusion portion 242. The crown irregularity portion 230 is located on the face side of the crown irregularity portion 240.

[0121] The contour line of the irregular crown portion 230 has a specific side CL231 located on the crown center side with respect to the center of the irregular crown portion 230. The contour line of the irregular crown portion 240 has a specific side CL241 located on the crown center side with respect to the center of the irregular crown portion 240.

[0122] The crown portion 12 has a crown rib 250. The crown rib 250 is provided on the inner surface of the crown portion 12. The crown rib 250 is simply indicated by a dashed line indicating its rib center line L250. The crown rib 250 is spaced apart from the crown irregular-shaped portion 230. The crown rib 250 is located between the crown irregular-shaped portion 230 and the crown center RC. The crown rib 250 is spaced apart from the crown irregular-shaped portion 240. The crown rib 250 is located between the crown irregular-shaped portion 240 and the crown center RC.

[0123] The crown rib 250 is disposed on the crown center side relative to the center of the crown irregular-shaped portion 230. The crown rib 250 is disposed on the crown center side relative to the center of the crown irregular-shaped portion 240. The crown rib 250 is disposed on the crown center side relative to the entire crown irregular-shaped portion 230. The crown rib 250 is disposed on the crown center side relative to the entire crown irregular-shaped portion 240.

[0124] The crown rib 250 is substantially parallel to the specific side CL231. The crown rib 250 is substantially parallel to the specific side CL241. A first end 250b of the crown rib 250 is located on the outer edge 12e of the crown portion 12. A second end 250f of the crown rib 250 is also located on the outer edge 12e. The entire crown irregularity portion 230 is located in an area 40 mm or less from the contour line CL4 of the crown portion 12. The entire crown irregularity portion 240 is located in an area 40 mm or less from the contour line CL4 of the crown portion 12. All of the multiple crown irregularity portions 230, 240 are located in an area 40 mm or less from the contour line CL4 of the crown portion 12.

[0125] Fig. 26 is a simulation image showing the vibration mode of a head 4x in which the crown rib 30 is removed from the head 4 of the first embodiment. Fig. 26 shows the first vibration mode. In this image, the magnitude of the amplitude relative to the maximum amplitude is shown by contour lines. In this image, the darker the area, the larger the amplitude.

[0126] Fig. 27 is a simulation image showing the vibration mode of a head 50x in which the crown rib 70 is removed from the head 50 of the second embodiment. Fig. 27 shows the first vibration mode. In this image, the magnitude of the amplitude relative to the maximum amplitude is shown by contour lines. In this image, the darker the area, the larger the amplitude.

[0127] The vibration mode is the shape of vibration determined by eigenvalue analysis (modal analysis) of the head. The vibration mode is also called the natural mode shape. The vibration mode is determined for each natural frequency. The vibration mode with the smallest natural frequency is the primary vibration mode. The primary, secondary, tertiary, etc. vibration modes are determined in order of decreasing natural frequency. The eigenvalue analysis of the head is performed by simulation.

[0128] This simulation uses the finite element method. In this finite element method, the three-dimensional data (computational model) of the head is divided into meshes. This mesh division can be performed using a commercially available preprocessor (such as HyperMesh). In addition, the longitudinal elastic modulus, density, and Poisson's ratio are used as the physical properties of the head material.

[0129] Eigenvalue analysis obtains the natural frequencies of the head and the vibration modes at each natural frequency. MSC Software's "Nastran" can be used as the eigenvalue analysis software. The constraint condition is a free support condition. This eigenvalue analysis determines multiple natural frequencies and the vibration modes at each natural frequency.

[0130] As shown in Figures 26 and 27, it was found that large amplitude vibrations occur near the irregular crown portion. The amplitude was particularly large near the center of the irregular crown portion. It was found that the presence of the irregular crown portion makes the crown portion 12 more susceptible to low frequency vibrations. Therefore, it was found that providing an irregular crown portion lowers the impact sound. It is believed that this low frequency vibration occurs due to bending at the bent portion. It is believed that vibrations occur such that the bent portion is the origin of the first vibration, and the origin of the second vibration is near the center of the crown.

[0131] As shown in Figures 26 and 27, it was found that the area with large amplitude was located near the irregular crown portion, but toward the crown center. Furthermore, it was found that the vibration extended to the vicinity of the crown center RC. The rigidity of the crown portion 12 is high at the outer edge 12e. For this reason, it is thought that almost no vibration occurs in the area on the outer edge 12e side of the irregular crown portion. On the other hand, the side closer to the crown center RC has lower rigidity than the outer edge 12e. For this reason, it is thought that large amplitude vibration occurs near the crown center of the irregular crown portion.

[0132] The crown rib 30 of the head 4 suppresses low-frequency vibrations caused by the irregular crown portion 20. The crown rib 30 is located in a portion of the head 4x where the amplitude is large. In this case, the vibration suppression effect is large. The crown rib 30 increases the first-order natural frequency, which increases the frequency of the impact sound. The first-order natural frequency of the head 4x was 3296 Hz, while the first-order natural frequency of the head 4 with the crown rib 30 was 3783 Hz.

[0133] The same is true for the head 50. The crown rib 70 of the head 50 suppresses low-frequency vibrations caused by the irregular crown portion 60. The crown rib 70 is arranged in a portion of the head 50x where the amplitude is large. In this case, the vibration suppression effect is large. The crown rib 70 increases the first-order natural frequency, which increases the frequency of the impact sound. The first-order natural frequency of the head 50x was 3053 Hz, while the first-order natural frequency of the head 50 with the crown rib 70 was 3436 Hz.

[0134] The central portion of the crown portion 12 has lower rigidity than the outer edge portion 12e. Therefore, the vibration antinode is located at the central portion of the irregular crown portion. By providing a crown rib at the central portion of the irregular crown portion, low-frequency vibrations are effectively suppressed, improving the low-pitched impact sound.

[0135] The crown rib may intersect with the irregular crown portion or may be spaced apart from the irregular crown portion. Because the central portion of the irregular crown portion is prone to vibration, locating the crown rib closer to the central portion of the irregular crown portion effectively suppresses low-frequency vibrations, thereby improving the impact sound.

[0136] The specific side is located near the center of the crown, where rigidity is low, and is therefore likely to be the origin of vibration. As shown in Figures 26 and 27, the areas with high amplitude are distributed substantially along the specific side of the irregular crown portion. By making the crown rib substantially parallel to the specific side, low-frequency vibrations are effectively suppressed, resulting in an improved impact sound.

[0137] The amplitude is large near the contour line of the irregular crown portion, but the vibration extends to the vicinity of the crown center RC. The amplitude decreases as the vibration approaches the crown center RC. Changing the position of the crown rib between the center C1 of the irregular crown portion and the crown center RC effectively adjusts the natural frequency. As a result, the pitch of the impact sound can be adjusted by changing the position of the crown rib. For example, as in head 130 (Figure 22), by moving the crown rib 150 away from the irregular crown portion 140 and closer to the crown center RC, the increase in the natural frequency can be suppressed. In this case, the impact sound is higher than when there is no crown rib, but lower than when the crown rib is positioned at the maximum amplitude location. The crown rib effectively adjusts the impact sound while improving an impact sound that is too low.

[0138] By positioning at least one end of the crown rib on the rigid outer edge 12e, the vibration suppression effect of the crown rib is enhanced, and the impact sound can be effectively raised in pitch. If both ends of the crown rib 210 are not positioned on the outer edge 12e, as in the head 190 (FIG. 24), the vibration suppression effect is reduced. This configuration is effective when adjusting the impact sound to a lower pitch.

[0139] If the face-side end of the crown rib is provided on the outer edge 12e, the crown rib can suppress deformation of the face portion 10 and reduce the restitution coefficient of the head. From this perspective, it is preferable that the face-side end of the crown rib be located on the back side of the outer edge 12f.

[0140] As shown in Figure 26, in the head 4x, the portion with the maximum amplitude in the first vibration mode is located in the crown portion 12. This is also true for the head 4 having the crown rib 30. On the other hand, if the sole rib 40 is removed from the head 4 (Figure 11), the portion with the maximum amplitude in the first vibration mode is located in the sole portion 14, and the vibration mode in Figure 26 is third-order. The sole portion 14 of the head 4 has the sole rib 40, which moves the portion with the maximum amplitude in the first vibration mode from the sole portion 14 to the crown portion 12. The presence of the sole rib 40 causes the maximum vibration region of the first mode to become the crown portion 12. Therefore, the crown rib 30 can change the first-order natural frequency. The first-order natural frequency has a greater effect on the pitch of the impact sound perceived by the golfer than the second-order and subsequent natural frequencies. Therefore, the crown rib 30 can effectively adjust the impact sound.

[0141] As shown in FIG. 27, in the head 50x, the portion with the maximum amplitude in the first vibration mode is located in the crown portion 12. This is also true for the head 50 having the crown rib 70. On the other hand, if the sole rib 80 is removed from the head 50 (FIG. 16), the portion with the maximum amplitude in the first vibration mode is located in the sole portion 14, and the vibration mode in FIG. 27 is second order. The sole portion 14 of the head 50 has the sole rib 80, which moves the portion with the maximum amplitude in the first vibration mode from the sole portion 14 to the crown portion 12. Due to the presence of the sole rib 80, the maximum vibration region in the first mode becomes the crown portion 12. Therefore, the crown rib 70 can change the first natural frequency. Therefore, the crown rib 70 can effectively adjust the impact sound.

[0142] The length of the crown rib is indicated by a double-headed arrow E1 in Fig. 22. The length E1 is measured in a plan view. The length E1 is the length (path length) of the rib center line in a plan view.

[0143] From the viewpoint of suppressing low-frequency vibrations caused by the irregular crown portion and raising the pitch of the impact sound, the length E1 of the crown rib is preferably 50 mm or more, more preferably 60 mm or more, and even more preferably 70 mm or more. The dimensions of the crown portion 12 are also limited due to the head volume restrictions imposed by the rules. From this viewpoint, the length E1 of the crown rib is preferably 110 mm or less, more preferably 105 mm or less, and even more preferably 100 mm or less.

[0144] When the contour line of the irregular crown portion has a specific side, the length of this specific side is not limited. If the specific side is long, the vibration of the crown portion 12 caused by this specific side will be greater. Therefore, if the specific side is long, the effect of the crown rib will be greater. From this perspective, the length of the specific side is preferably 15 mm or more, more preferably 20 mm or more, and more preferably 25 mm or more. If the specific side is too long, the impact sound will tend to be excessively low. From this perspective, the length of the specific side is preferably 70 mm or less, more preferably 60 mm or less, more preferably 50 mm or less, more preferably 45 mm or less, and more preferably 40 mm or less. The length of the specific side is measured in a planar view. The length of the specific side is the length (path length) in a planar view.

[0145] The irregular crown portion 20 of the first embodiment has a side wall surface 24 (FIG. 3). As described above, the specific side CL24 is the base point of the side wall surface 24. In other words, the specific side CL24 is the lower edge of the side wall surface 24. In this case, the bending angle of the curved portion 28 of the irregular crown portion 20 becomes large, and the crown portion 12 is likely to vibrate. Therefore, in this case, the crown rib 30 has a high effect of improving and adjusting the impact sound.

[0146] The position of the crown irregularity portion in the crown portion 12 is not limited. In each of the above embodiments, the crown irregularity portion is located on the heel side of the crown center RC. The crown irregularity portion may be located, for example, on the toe side of the crown center RC. The crown irregularity portion may be located, for example, on the back side of the crown center RC. It is preferable that the crown irregularity portion be located at a position offset from the crown center RC.

[0147] The base surface b1 of the crown outer surface 12a is a convex curved surface overall, but there is a relatively flat portion near the hosel portion 16. The portion connecting the crown outer surface 12a to the outer surface of the hosel portion 16 is a concave curved surface. Therefore, a transition portion is formed on the crown outer surface 12a, transitioning from a convex curved surface to a concave curved surface, and this transition portion is relatively flat. This transition portion is located close to the hosel portion 16 and on the heel side of the crown portion 12. This transition portion has lower rigidity than the convex curved portion. If this transition portion is close to the irregular crown portion, areas prone to vibration are adjacent, making low-frequency vibrations more likely to occur. Therefore, in this case, the placement of a crown rib is highly effective. From this perspective, it is preferable that the entire irregular crown portion be located heelward of the crown center RC. It is also preferable that the entire irregular crown portion be located heelward of the face center Fc.

[0148] In FIG. 5, the double-headed arrow D1 indicates the distance between each point on the contour line CL20 and the contour line CL4 of the crown portion 12. This distance D1 is defined as the distance (straight-line distance) on the cross-sectional line. By reducing the minimum value of the distance D1, the irregular crown portion 20 approaches the outer edge 12e. In this case, vibration of the crown portion 12 on the outer edge 12e side of the irregular crown portion 20 is effectively suppressed. Therefore, the impact sound improvement and impact sound adjustment effects can be achieved only with the crown rib 30 on the crown center side of the irregular crown portion 20. From this perspective, the minimum value of the distance D1 is preferably 20 mm or less, more preferably 15 mm or less, and even more preferably 10 mm or less. The minimum value of the distance D1 may be 0 mm.

[0149] In Figure 22, the double-headed arrow D2 indicates the shortest distance between the rib center line of the crown rib and the specific side. The position of the antinode of vibration of the crown portion 12 caused by the irregular crown portion is close to the specific side. From the perspective of raising the pitch of the impact sound, the distance D2 is preferably 20 mm or less, more preferably 15 mm or less, and even more preferably 10 mm or less. As mentioned above, the distance D2 may be zero. If a lower pitch is desired for the impact sound, the distance D2 can be increased. By changing the distance D2, the impact sound can be effectively adjusted.

[0150] From the viewpoint of increasing the rigidity of the crown portion by the crown rib, the height Hr of the crown rib (FIG. 13(b)) is preferably 2.5 mm or more, more preferably 3 mm or more, and still more preferably 3.5 mm or more. From the viewpoint of reducing the weight of the crown rib, the height Hr of the crown rib is preferably 7.5 mm or less, more preferably 7 mm or less, and still more preferably 6.5 mm or less.

[0151] From the viewpoint of freedom in head design, the maximum height of the irregular crown portion may be 1 mm or more, further 2 mm or more, or even 3 mm or more. From the viewpoint of ease of manufacture, the maximum height of the irregular crown portion may be 10 mm or less, further 9 mm or less, or even 8 mm or less. The maximum height of the irregular crown portion is the maximum value of the height Ht (see FIG. 9).

[0152] In FIG. 3, the double-headed arrow W2 indicates the longest transverse length of the contour line CL20 in a plan view. This longest transverse length W2 is the maximum length of a line segment S3 that has a first end at a first point on the contour line CL20 and a second end at a second point on the contour line CL20. From the viewpoint of increasing the degree of freedom in head design, the longest transverse length W2 is preferably 30 mm or more, more preferably 35 mm or more, and even more preferably 40 mm or more. From the viewpoint of the impact sound, the longest transverse length W2 is preferably 80 mm or less, more preferably 75 mm or less, and even more preferably 70 mm or less.

[0153] To increase the degree of freedom in head design, the total area of ​​the irregular crown portion in plan view is 250mm 2 More than 300mm is preferable. 2More than 350mm is preferable. 2 From the viewpoint of the hitting sound, the total area of ​​the irregular crown portion in a plan view is preferably 1400 mm 2 Less than 1300mm is preferable 2 Less than 1200mm is preferable. 2 More preferably, the total area is the area of ​​the figure defined by the contour line CL20. If there is more than one crown variant, the total area is the sum of the areas of each crown variant.

[0154] When the head volume is large, the impact sound tends to be louder. Also, when the dimensions of the crown portion 12 are large, the impact sound is significantly affected by the irregular crown portion. For this reason, the crown rib of the present disclosure is highly effective when the head volume is large. From this perspective, the head volume is set to 200 cm 3 More than 300cm is preferable. 3 More than 410cm is preferable. 3 More than 430cm is preferable. 3 More than 450cm is preferable. 3 From the viewpoint of golf rules, the head volume is 470 cm 3 Less than 465cm is preferable. 3 Less than 460cm is preferable. 3 The following is more preferred:

[0155] The following notes are provided regarding the above-described embodiments. [Appendix 1] A hollow golf club head, a face portion that forms a hitting face; a crown portion forming an outer crown surface and an inner crown surface; a sole portion that forms an outer sole surface and an inner sole surface; A hosel portion, It has The crown portion has a crown irregularly shaped portion and a crown rib provided on an inner surface of the crown, the irregular crown portion is a crown convex portion that forms a concave portion on the crown inner surface and a convex portion on the crown outer surface, or a crown concave portion that forms a convex portion on the crown inner surface and a concave portion on the crown outer surface, The golf club head has a crown rib disposed on the crown center side with respect to the center of the irregular crown portion. [Appendix 2] 2. The golf club head according to claim 1, wherein the crown rib is disposed toward the center of the crown relative to the entire irregular crown portion. [Appendix 3] 3. The golf club head according to claim 1, wherein at least one end of the crown rib is located on the outer edge of the crown portion. [Appendix 4] 4. The golf club head according to any one of claims 1 to 3, wherein the entire irregular crown portion is located within an area of ​​40 mm or less from the contour line of the crown portion. [Appendix 5] The contour line of the crown irregular-shaped portion has at least one side, 5. The golf club head according to any one of claims 1 to 4, wherein the at least one side includes a specific side located on the crown central side relative to the center of the crown irregular portion. [Appendix 6] 6. The golf club head according to claim 5, wherein the crown rib is substantially parallel to the specific side. [Appendix 7] 7. The golf club head according to any one of claims 1 to 6, wherein the sole portion has a sole rib that moves the portion of the head with the maximum amplitude in the primary vibration mode from the sole portion to the crown portion. [Explanation of symbols]

[0156] 2. Golf clubs 4, 50, 90, 130, 160, 190, 220... head 6. Shaft 10. Face part 10a···Striking face 12 Crown part 12a: Crown outer surface 12b: Inner surface of crown 14. Sole 14a···Outer surface of sole 14b: Inner surface of sole 16···Hosel part 20, 60, 100, 140, 170, 200, 230, 240... Crown irregular section 26,62,142,172,202,232,242···Crown convex part 102 Crown recess 30, 70, 110, 150, 180, 210, 250... Crown Rib 40, 80, 120... Sole rib CL24, CL65, CL104, CL144, CL171, CL201, CL231, CL241...Specific side CL2: Head contour in plan view CL4: Outline of the crown in plan view RC · · · Crown center C1: Center of irregular crown part Z: Shaft axis

Claims

1. A hollow golf club head, a face portion that forms a hitting face; a crown portion forming an outer crown surface and an inner crown surface; a sole portion that forms an outer sole surface and an inner sole surface; A hosel portion, It has The crown portion has a crown irregularly shaped portion and a crown rib provided on an inner surface of the crown, the irregularly shaped crown portion is a crown protrusion portion that forms a recess on the inner surface of the crown and a protrusion on the outer surface of the crown, the crown convex portion is a portion that further protrudes from the crown base surface that forms a convex curved surface, the crown rib is spaced from the crown profile portion, the crown rib is disposed on the crown center side with respect to the center of the crown irregularly shaped portion, A golf club head in which the center of the irregular crown portion is the centroid of the contour line of the irregular crown portion in a plan view of the golf club head.

2. 2. The golf club head according to claim 1, wherein the crown rib is disposed on the crown center side with respect to the entirety of the irregular crown portion.

3. 3. The golf club head according to claim 1, wherein at least one end of the crown rib is located on an outer edge of the crown portion.

4. 4. The golf club head according to claim 1, wherein the entire irregular crown portion is disposed within an area of ​​40 mm or less from the contour line of the crown portion.

5. The contour line of the crown irregular-shaped portion has at least one side, the at least one side includes a specific side located on a crown center side with respect to a center of the crown irregular-shaped portion, 5. The golf club head according to claim 1, wherein the side is a part bounded by a corner having a radius of curvature of 10 mm or less in a shape of the outline of the irregular crown portion in a plan view, and is a straight line or a curve having a radius of curvature of 25 mm or more.

6. 6. The golf club head according to claim 5, wherein the crown rib is substantially parallel to the particular side.

7. 7. The golf club head according to claim 1, wherein the sole portion has a sole rib that moves a portion of the golf club head having a maximum amplitude in a primary vibration mode from the sole portion to the crown portion.

8. 8. The golf club head according to claim 1, wherein the crown rib is disposed between the contour line of the irregular crown portion and the center of the crown portion in a plan view of the golf club head.

9. 9. The golf club head according to claim 1, wherein the entirety of the irregular crown portion is located on the heel side of the face center, which is the center of the striking face.

10. 10. The golf club head according to claim 1, wherein the contour line of the irregular crown portion is a boundary line between the crown base surface and the crown protrusion.

Images