Golf Club Head

Abstract

To provide a golf club head which has a high moment of inertia and can lower the center of gravity.SOLUTION: A golf club head 1 having a hollow part i in the inside includes a face 2, a crown 3, and a sole 4. In a reference state in which the head 1 is placed on a horizontal plane HP at a prescribed lie angle and a loft angle, a thick part 10 is formed in the back of the sole in the sole 4. The thick part 10 extends along a contour in the back of the head in a plane view of the head. The thick part 10 includes an upper surface part 11 facing an inner surface of the crown 3 in the hollow part i. A height h from the horizontal plane HP of a head rear end 11e of the upper surface part 11 is 20 to 37% of a head maximum thickness H.SELECTED DRAWING: Figure 6

Description

[Technical field]

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

[0002] In recent years, golf club heads have been proposed that have an increased moment of inertia (mainly the moment of inertia about a vertical axis passing through the center of gravity of the head) in order to improve the directionality of hit balls.

[0003] For example, the following Patent Document 1 describes a wood-type golf club head in which a solid portion is provided on the back face side and the length of this solid portion in the front-to-rear direction from the rear end point of the head is limited to a certain range. In the wood-type golf club head of Patent Document 1, the solid portion distributes a large amount of weight to the rear of the head, increasing the moment of inertia and the depth of the center of gravity. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2009-112584 A DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0005] There is a need for golfers to further increase the flight distance of a shot while improving the directionality of the shot. One attempt to increase the flight distance of a shot is to lower the center of gravity of the head. By lowering the center of gravity of the head, the sweet spot is brought closer to the actual hitting point, and the flight distance of the shot is improved.

[0006] However, the golf club head as disclosed in Patent Document 1 has room for further improvement in terms of lowering the center of gravity.

[0007] The present disclosure has been made in view of the above circumstances, and has as its main object to provide a golf club head that has a large moment of inertia while allowing a low center of gravity. [Means for solving the problem]

[0008] The present disclosure relates to a golf club head having a hollow portion therein, the golf club head having a face, a crown and a sole, wherein in a standard state in which the golf club head is placed on a horizontal plane at a specified lie angle and loft angle, a thick portion is formed on the rear of the sole, the thick portion extends along the rear contour of the head in a plan view of the head, the thick portion has an upper surface portion facing the inner surface of the crown within the hollow portion, and the height of the rear end of the upper surface portion from the horizontal plane is 20% to 37% of the maximum thickness of the head. Effect of the Invention

[0009] The golf club head of the present disclosure employs the above-described configuration, and thus is capable of providing a large moment of inertia while achieving a low center of gravity. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is a plan view of the golf club head of the present embodiment. [Diagram 2] FIG. 2 is a front view of the golf club head of the present embodiment. [Diagram 3] FIG. 2 is a side view of the golf club head of the present embodiment as viewed from the toe side. [Figure 4] FIG. 2 is a bottom view of the golf club head of the present embodiment. [Diagram 5] 1 is a perspective view of a golf club head according to an embodiment of the present invention. [Figure 6] 1 is a vertical cross-sectional view of a golf club head according to an embodiment of the present invention. [Figure 7] FIG. 7 is an enlarged view of the rear end side of the head in FIG. [Figure 8]3 is a cross-sectional view showing the details of a thick portion by cutting away the crown side of the golf club head of the present embodiment. FIG. [Figure 9] 3 is a cross-sectional view showing the details of a thick portion by cutting away the toe side of the golf club head of the present embodiment. FIG. [Figure 10] FIG. 2 is a plan view of the golf club head of the present embodiment with a portion of the crown removed. [Figure 11] FIG. 2 is a plan view of a golf club head of a comparative example. [Figure 12] 12 is a cross-sectional view taken along line XII-XII in FIG. 11. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, one embodiment of the present disclosure will be described with reference to the drawings. In this specification, the same or common elements are denoted by the same reference numerals, and duplicated explanations are omitted. Furthermore, the specific configurations shown in the embodiments and drawings are for understanding the contents of the present disclosure, and the present disclosure is not limited to the specific configurations shown in the drawings.

[0012] 1 to 5 respectively show a plan view, a front view, a side view seen from the toe side, a bottom view and a perspective view of a golf club head (hereinafter sometimes simply referred to as a "head") 1 of this embodiment.

[0013] 1 to 4, the head 1 is placed in a standard state. In this specification, the standard state of the head 1 is a state in which the head 1 is placed on a horizontal plane HP with a specified lie angle α (FIG. 2) and loft angle β (FIG. 3). As shown in FIG. 3, in the standard state, the head 1 is held at a lie angle α and a loft angle β with the shaft axis center line CL of the head 1 being disposed within a standard vertical plane VP. In this specification, unless otherwise specified, the head 1 is described as being in the standard state.

[0014] The prescribed lie angle α and loft angle β are the lie angle and loft angle determined and obtained for the head, and are usually listed in a product catalog.

[0015] The shaft axial center line CL is substituted for the axial center line of the shaft insertion hole of the hosel 5 .

[0016] In addition, in the reference state of the head 1, the direction perpendicular to the reference vertical plane VP is defined as the front-to-back direction of the head. With respect to the front-to-back direction of the head, the side of the face 2 is defined as the front side, and the opposite side is defined as the rear side. In addition, the direction parallel to both the reference vertical plane VP and the horizontal plane HP is defined as the toe-heel direction. Furthermore, the direction perpendicular to the horizontal plane HP is defined as the up-down direction of the head.

[0017] As shown in Figs. 1 to 5, the head 1 of this embodiment is configured as a wood type. In this specification, the "wood type" head 1 is a concept that includes not only drivers but also fairway woods such as spoons and buffys. As a desirable aspect, the head 1 of this embodiment has a head volume of, for example, 400cc or more, preferably 420cc or more, and more preferably 430cc or more. Note that the head volume may be 470cc or less due to restrictions of the golf rules. In other embodiments, the head 1 may be configured as an iron type, a hybrid type, or the like.

[0018] The head 1 integrally includes, for example, a face 2, a crown 3, a sole 4, a hosel 5, a toe 6, and a heel 7, and has a hollow portion (FIG. 6) formed therein.

[0019] The face 2 constitutes a hitting surface for hitting a ball on its front surface. Although not shown, the face 2 may be provided with a plurality of grooves called face lines extending in the toe-heel direction.

[0020] The crown 3 extends from the upper edge of the face 2 toward the rear of the head and forms the top surface of the head. A hosel 5 for fixing a golf shaft (not shown) is formed on the heel side of the crown 3.

[0021] In this embodiment, the crown 3 is formed to have the smallest thickness in the head 1. Such a head 1 reduces the weight of the upper part of the head, and thus lowers the center of gravity of the head 1. In a preferred embodiment, the thickness of the crown 3 is desirably set to, for example, about 0.30 to 1.00 mm.

[0022] In a plan view of the head, the crown 3 includes a crown edge 3e that defines a head rear contour S. This crown edge 3e is curved, for example, in a convex arc shape toward the rear of the head, as shown in Fig. 1. In addition, as shown in Fig. 3, the portion of the head 1 according to this embodiment below the crown edge 3e is located on the inner side of the head (closer to the head center of gravity G) than the crown edge 3e.

[0023] The sole 4 extends from the lower edge of the face 2 toward the rear of the head and forms the bottom surface of the head. Therefore, the sole 4 is a visible portion excluding the hosel 5 when viewed from the bottom of the head (FIG. 4).

[0024] The head 1 is made of, for example, a metal material. Suitable metal materials include, for example, stainless steel, maraging steel, titanium alloy, magnesium alloy, aluminum alloy, etc. A part of the head 1 (for example, the crown 3) may be made of a non-metal material such as fiber reinforced resin.

[0025] 6 shows a cross-sectional view of the head 1. As shown in FIG. 1, this cross-sectional view is a vertical cross section (head vertical cross section) that passes through the head center of gravity G and includes a first straight line L1 that is parallel to the front-rear direction of the head. The head 1 of this embodiment is formed by fixing a face plate 1A to a head main body 1B that has a face opening O for fixing the face plate 1A. The head main body 1B is integrally formed by casting (lost work precision casting) a metal material such as a titanium alloy, for example.

[0026] FIG. 7 is an enlarged view of a main part of FIG. 6. As shown in FIG. 6 and FIG. 7, the sole 4 has a thick portion 10 formed at the rear of the sole. The thick portion 10 is formed by locally increasing the thickness of the sole 4. As shown by the dashed line in FIG. 1, the thick portion 10 extends along the rear contour S of the head in a plan view of the head. Such a thick portion 10 distributes more mass to a rear position of the head away from the center of gravity G of the head. Therefore, the head 1 of this embodiment has a moment of inertia Iz about a vertical axis passing through the center of gravity G of the head (hereinafter, simply referred to as "moment of inertia Iz").

[0027] 6 and 7, the thick portion 10 of this embodiment has an upper surface portion 11 that faces the inner surface 3i of the crown 3 within the hollow portion i. In the head vertical cross section of FIG. 6, the height h of the head rear end 11e of the upper surface portion 11 from the horizontal plane HP is set to 20% to 37% of the head maximum thickness H. The head maximum thickness H is the vertical height from the horizontal plane HP to the highest point of the head 1. In this way, by limiting the height h of the head rear end 11e of the upper surface portion 11 of the thick portion 10 to a certain range with respect to the head maximum thickness H, it is possible to lower the center of gravity of the head 1.

[0028] Here, if the height h of the head rear end 11e of the top surface portion 11 exceeds 37% of the head maximum thickness H, a lot of weight is disposed at a high position of the head 1, making it difficult to lower the center of gravity of the head 1. Conversely, if the height h of the head rear end 11e of the top surface portion 11 is less than 20% of the head maximum thickness H, the weight disposed at the rear of the head is reduced, and the effect of increasing the moment of inertia Iz by the thick portion 10 is not sufficiently obtained. From this viewpoint, the height h of the head rear end 11e of the top surface portion 11 from the horizontal plane HP is desirably 21% or more, or even 23% or more, of the head maximum thickness H, and is desirably 36% or less, or even 34% or less.

[0029] As described above, the head 1 of the present embodiment is provided with a large moment of inertia Iz while allowing the center of gravity to be lowered.

[0030] In a preferred embodiment, the head 1 of this embodiment has a surface roughness of, for example, 5000 (g cm2 ) or more, preferably 5100 (g cm 2 ) or more, and more preferably 5200 (g cm 2 ) or more, preferably 5300 (g cm 2 ) or more, especially 5400 (g cm 2 The larger the moment of inertia Iz, the better, and the upper limit is within the range of the rules of golf (5900 (g cm 2 ) + Test Tolerance 100 (g cm 2 ) below) are not particularly limited.

[0031] In a preferred embodiment, the head 1 of this embodiment has a center of gravity height CGH of, for example, 30 mm or less, preferably 29 mm or less, and more preferably 28 mm or less. The center of gravity height CGH is the height from the horizontal plane HP to the head center of gravity G, as shown in Fig. 6. The lower the center of gravity height CGH, the more desirable it is, and there is no particular lower limit.

[0032] The thickness t (maximum thickness) of the thick portion 10 is not particularly limited as long as it is thicker than other portions of the sole 4, but is preferably 2.5 mm or more, more preferably 3.0 mm or more, and even more preferably 4.0 mm or more. The upper limit of the thickness t of the thick portion 10 is, for example, 12.0 mm or less, preferably 11.0 mm or less, and even more preferably 10.0 mm or less.

[0033] In a preferred embodiment, the thick portion 10 extends across the first straight line L1 in a plan view of the head. That is, the toe side end 10a of the thick portion 10 is located closer to the toe side than the first straight line L1, and the heel side end 10b of the thick portion 10 is located closer to the heel side than the first straight line L1. This embodiment helps to increase the moment of inertia Iz.

[0034] In the head 1 of this embodiment, the crown 3 and the sole 4 are integrally molded by casting. Therefore, if the thick part 10 is directly connected to the crown 3 having a smaller thickness, the difference in thickness between the two parts may cause casting deformation such as sink marks on the crown 3 having a smaller thickness, which may deteriorate the appearance of the crown 3. Since the crown 3 is the part that is directly seen when a golfer sets up, maintaining a good appearance is an important issue.

[0035] In view of the new problem as described above, as shown in Fig. 7, in the thick-walled portion 10 of this embodiment, the head rear end 11e of the upper surface portion 11 is located below the crown edge portion 3e. In such a head 1, since the thick-walled portion 10 is not directly connected to the crown 3, casting deformation in the crown 3 is suppressed, and the appearance of the crown 3 can be maintained in a good condition. Even if casting deformation occurs near the head rear end 11e of the thick-walled portion 10, this portion is located below the crown edge portion 3e, so it is hardly visible when the golfer holds the head 1.

[0036] In order to increase the moment of inertia Iz while maintaining the good appearance of the crown 3, it is preferable that the upper surface 11 of the thick portion 10 is inclined downward toward the head rear end 11e in the head vertical cross section including the head center of gravity G. With this configuration, the head rear end 11e of the upper surface 11 of the thick portion 10 is positioned lower than the crown edge 3e, while the volume of the thick portion 10 on the head front side can be sufficiently secured, and the moment of inertia Iz can be effectively increased. It is particularly preferable that such an inclination is satisfied over the entire range in the length direction of the thick portion 10, not only in the head vertical cross section including the first straight line L1. The inclination may be a constant inclination, or may be a multi-step inclination with different angles.

[0037] When the crown 3 and the sole 4 are integrally molded by casting, as in the head 1 of this embodiment, it is desirable that the angle θ between the upper surface 11 of the thick portion 10 and the horizontal plane HP in the vertical section of the head including the first straight line L1 is 20° or less. Generally, in casting, a lost wax model is created using a metal mold and an assembly core (both not shown). The assembly core is placed in the space corresponding to the hollow portion i, and after the wax model has solidified, it is sequentially removed from the portion corresponding to the face opening O. By setting the angle θ to 20° or less, the assembly core can be easily removed.

[0038] 8 and 9 are cross-sectional views showing the details of the thick portion 10 by cutting away the crown side and the toe side of the head 1, respectively. Also, Fig. 10 is a plan view of the head 1 with a part of the crown 3 removed. As shown in Figs. 8 to 10, the thick portion 10 includes a first portion 101 located on the toe side, a second portion 102 located on the heel side, and a third portion 103 located between the first portion 101 and the second portion 102.

[0039] The first portion 101 and the second portion 102 each have a width W measured in a direction perpendicular to the head rear contour S. The widths W of the first portion 101 and the second portion 102 gradually decrease toward the respective ends, i.e., toward the toe side and heel side of the head rear contour S, respectively. Such a thick-walled portion 10 can prevent a large rigidity difference from being formed at the toe side end 10a and the heel side end 10b of the thick-walled portion 10, thereby preventing a deterioration in head durability. In addition, the gradual decrease in the width W suppresses casting deformation at the ends of the thick-walled portion 10.

[0040] From the viewpoint of increasing the moment of inertia Iz, the maximum width W of the first portion 101 and the second portion 102 is, for example, 3.0 mm or more, preferably 5.0 mm or more, and more preferably 7.0 mm or more. On the other hand, since there is a practical restriction on the head weight of a golf club head, from the viewpoint of satisfying this restriction, the maximum width W of the first portion 101 and the second portion 102 is, for example, 17.0 mm or less, preferably 15.0 mm or less, and more preferably 13.0 mm or less.

[0041] In a preferred embodiment, the inner edges 101e and 102e of the first portion 101 and the second portion 102 on the side of the head center of gravity G extend substantially on a virtual circle VR passing through the head center of gravity G. Such a thick portion 10 can more effectively distribute a large weight to the outside of the head center of gravity G, providing a larger moment of inertia Iz. In this embodiment, in a plan view of the head, the inner edge 101e of the first portion 101 and the inner edge 102e of the second portion 102 extend substantially on a virtual circle VR of a radius Re. With regard to this feature, the term "substantially" includes an embodiment in which, taking into consideration manufacturing errors, even if each of the inner edges 101e and 102e deviates from the virtual circle VR, the amount of deviation is 5% or less of the radius R1 of the virtual circle VR.

[0042] 10, in a plan view of the head, when a circle centered on the head center of gravity G and circumscribing the head rear contour S is defined as a first circle 200, and a circle concentric with the first circle 200 and having a radius R1 that is 80% of the radius Rmax of the first circle 200 is defined as a second circle 300, the first portion 101 and the second portion 102 are positioned outside the second circle 300 and are not positioned inside the second circle 300. This embodiment is effective in distributing the weight of the thick portion 10 to a position farther away from the head center of gravity G and further increasing the moment of inertia Iz.

[0043] The third portion 103 of this embodiment is formed so as to locally protrude toward the front side of the head with respect to the first portion 101 and the second portion 102. For example, the third portion 103 of this embodiment protrudes so as to be located inside the imaginary circle VR (toward the head center of gravity G). In addition, for example, a weight member 20 (see FIGS. 4 and 6) may be disposed in the third portion 103 by utilizing the space in the front-rear direction of the head. The weight member 20 is made of a material having a different specific gravity from that of the thick portion 10, for example.

[0044] The weight member 20 may be made of, for example, a material having a higher specific gravity than the thick portion 10. In this case, the head 1 can have a larger moment of inertia Iz and a lower head center of gravity G. Such a weight member 20 may be made of, for example, stainless steel, a tungsten alloy, or the like.

[0045] On the other hand, in order to reduce the head weight, the weight member 20 may be made of a material having a lower specific gravity than the thick portion 10. Such a weight member 20 may be made of, for example, aluminum, an aluminum alloy, a magnesium alloy, or the like.

[0046] As shown in Figs. 6 and 7, the weight member 20 has an upper surface 21. The upper surface 21 of the weight member 20 abuts against a recess formed in the thick portion 10. The upper surface 21 of the weight member 20 includes, for example, a first surface 21a and a second surface 21b located below and behind the head via a step from the first surface 21a. Such a weight member 20 helps to further promote a lower center of gravity while providing a larger moment of inertia Iz. In addition, the weight member 20 of this embodiment can contact the thick portion 10 over a large area, improving the joining strength.

[0047] In this embodiment, the weight member 20 is fixed to the sole 4 from the outside of the sole 4 by a removable fastener 30. The fastener 30 in this embodiment is, for example, a screw member, and extends so as to penetrate the first surface 21a of the upper surface 21 of the weight member 20. In another aspect, the weight member 20 may be fixed by a double-sided adhesive tape, an adhesive, or the like.

[0048] Although the embodiments of the present disclosure have been described in detail above, the present disclosure is not limited to the above specific disclosure, and can be implemented with various modifications within the scope of the technical ideas described in the claims. EXAMPLES

[0049] More specific, non-limiting examples of the present disclosure are described below. A golf club head having the basic structure shown in FIGS. 1 to 10 was prototyped based on the specifications in Table 1 (Example), and the moment of inertia Iz and the height of the center of gravity CGH were measured.

[0050] For comparison, a CAD model of a golf club head (comparative example) was created, in which a solid portion 400 spanning the crown and sole is provided at the rear of the head, as described in Patent Document 1, as shown in Figures 11 and 12. Then, the moment of inertia Iz and the height of the center of gravity CGH of the comparative example were estimated by calculation. The shape of the head was the same, except for the difference between the thick portion and the solid portion. The shape of the solid portion 400 was designed so that the weight would be the same as that of the thick portion of the example.

[0051] [Table 1]

[0052] As is clear from Table 1, the golf club head of the embodiment has a compressive strength of 5500 (g cm 2 It was confirmed that the height CGH of the head center of gravity can be suppressed to 30.0 mm or less while having a large moment of inertia Iz of 10.0 mm or more. On the other hand, it was confirmed that the golf club head of the comparative example has a large moment of inertia, but the height of the head center of gravity is 32.0 mm, and a low center of gravity cannot be realized. In addition, in the comparative example, when casting deformation occurs at the joint between the solid portion and the crown, the deformed portion is clearly visible to the golfer holding the golf club head, but in the embodiment, it was confirmed that such casting deformation of the crown does not occur.

[0053] [Note] The present disclosure includes the following aspects.

[0054] [Disclosure 1] A golf club head having a hollow portion therein, A face, a crown and a sole, In a standard state in which the golf club head is placed on a horizontal plane with a specified lie angle and loft angle, The sole has a thick portion formed at the rear of the sole, the thick portion extends along a rear contour of the head in a plan view of the head, the thick-walled portion has an upper surface portion facing an inner surface of the crown within the hollow portion, The height of the rear end of the upper surface portion from the horizontal plane is 20% to 37% of the maximum thickness of the head. Golf club head. [Disclosure 2] The golf club head according to Disclosure 1, wherein, in a plan view of the head in the reference state, the thick portion extends so as to cross a first straight line that passes through the center of gravity of the head and is parallel to the front-rear direction of the head. [Disclosure 3] the crown includes a crown edge that defines the head rear contour; The golf club head according to Disclosure 2, wherein the thick portion is such that the rear end of the upper surface portion is located lower in the head than the crown edge portion. [Disclosure 4] The golf club head according to Disclosure 3, wherein in a vertical cross section of the head passing through the center of gravity of the head, the upper surface portion slopes downward toward the rear end of the head. [Disclosure 5] The golf club head according to Disclosure 3 or 4, wherein an angle between the top surface portion and the horizontal plane is 20° or less in a vertical cross section of the head passing through the center of gravity of the head. [Disclosure 6] In a plan view of the head in the reference state, the thick-walled portion includes a first portion located on a toe side, a second portion located on a heel side, and a third portion located between the first portion and the second portion, The golf club head according to any one of Disclosures 1 to 5, wherein a weight member having a specific gravity different from that of the thick portion is disposed in the third portion. [Disclosure 7] The golf club head of Disclosure 6, wherein the widths of the first and second portions measured perpendicular to the head rear contour gradually decrease toward the toe and heel sides, respectively, of the head rear contour. [Disclosure 8] The golf club head according to Disclosure 6 or 7, wherein the inner edges of the first and second parts, which are edges on the head center of gravity side, extend substantially on an imaginary circle passing through the head center of gravity. [Disclosure 9] The golf club head according to Disclosure 8, wherein the third portion is located inside the imaginary circle. [Disclosure 10] A golf club head as described in any one of disclosures 6 to 9, wherein, in a planar view of the head in the reference state, a first circle is a circle that is centered on the head center of gravity and circumscribes the head rear contour, and a second circle is a circle that is concentric with the first circle and has a radius that is 80% of the first circle, the first portion and the second portion are located outside the second circle. [Explanation of symbols]

[0055] 1 Head 2 Face 3 Crowns 3e Crown edge 4 Sole 6 Tou 7 Heel 10 Thick part 11 Upper surface of thick part 11e Rear end of head 20 Weight material 21 Top side 101 Part 1 101e inner edge 102 Part 2 102e inner edge 103 Part 3 200 1st Yen 300 2nd Yen S Head Rear Contour

Claims

1. A golf club head having a hollow portion therein, A face, a crown and a sole, In a standard state in which the golf club head is placed on a horizontal plane with a specified lie angle and loft angle, The sole has a thick portion formed at the rear of the sole, the thick portion extends along a rear contour of the head in a plan view of the head, the thick-walled portion has an upper surface portion facing an inner surface of the crown within the hollow portion, a height of the rear end of the upper surface portion from the horizontal plane is 20% to 37% of a maximum thickness of the head; the thick portion extends so as to cross a first straight line passing through a center of gravity of the head and parallel to a front-rear direction of the head, When viewed from above in the reference state, the thick-walled portion includes a first portion located on a toe side, a second portion located on a heel side, and a third portion located between the first portion and the second portion, A weight member having a specific gravity greater than that of the thick-walled portion is disposed in the third portion, a width of the first portion and a width of the second portion measured in a direction perpendicular to the head rear contour gradually decrease toward a toe side and a heel side of the head rear contour, respectively; when a circle circumscribing the head rear contour centered on the head center of gravity is defined as a first circle in a plan view of the head in the reference state, and a circle concentric with the first circle and having a radius that is 80% of the radius of the first circle is defined as a second circle, the first portion and the second portion are located outside the second circle, Golf club head.

2. The crown includes a crown edge portion that defines the head rear contour, 2. The golf club head according to claim 1, wherein the thick portion is such that the rear end of the upper surface is located lower on the head than the crown edge.

3. A golf club head as described in claim 1 or 2, wherein in a vertical cross section of the head passing through the center of gravity of the head, the upper surface portion slopes downward toward the rear end of the head.

4. 4. The golf club head according to claim 1, wherein an angle between said top surface and said horizontal plane is 20[deg.] or less in a vertical cross section of the head passing through the center of gravity of the head.

5. A golf club head as described in any one of claims 1 to 4, wherein the inner edges of the first and second parts which are the edges on the head center of gravity side extend substantially on an imaginary circle passing through the head center of gravity.

6. The golf club head of claim 5, wherein the third portion is located inside the virtual circle.

7. A golf club head as claimed in claim 1, wherein a moment of inertia Iz about a vertical axis passing through the head center of gravity G is 5,500 g·cm 2 or more, and a height CGH of the head center of gravity is 30.0 mm or less.

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