Golf Club Head

Abstract

To prevent the toe of a golf club head from getting down during downswing.SOLUTION: A golf club head 1 includes a face 2 for hitting a ball, and a crown 3 forming the top face of the head. The crown 3 includes a first portion 31 adjacent to the face 2, and a second portion 32 connected to the back head side of the first portion 31. The second portion 32 is located below the first portion 31 via a step portion 6. The first portion 31 includes a face-vicinity portion 311 extending in a toe-heel direction along the face 2, and a heel-vicinity portion 312 connected to an end of the face-vicinity portion 311 on a heel H side and extending backwardly of the head along the contour of the crown 3 on the heel H side. In a head plan view, a length A in the front-back direction of the head from a leading edge Le to an end 312e of the heel-vicinity portion 312 on the back head side is equal to or more than 70% of a club head maximum length B in the head front-back direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a golf club head. [Background technology]

[0002] The following Patent Document 1 describes a golf club head having a step in the crown. In this golf club head, the rear side of the step is lower than the front side of the step, which is expected to have the effect of lowering the center of gravity of the head. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-124360 A DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0004] In a typical golf club, the center of gravity of the head is located away from the axis of the golf club shaft toward the toe of the head. Therefore, as shown in FIG. 14, a so-called toe-down phenomenon may occur during the downswing. Toe-down is a phenomenon in which the toe of the golf club head drops due to centrifugal force during the downswing. Toe-down changes the position or posture of the golf club head at impact, which in turn reduces the distance and direction of the ball.

[0005] The present invention has been devised in view of the above problems, and has as its main object to provide a golf club head capable of suppressing toe-down. [Means for solving the problem]

[0006] The present invention is a golf club head including a face for hitting a ball and a crown forming an upper surface of the head, the crown including a first portion adjacent to the face and a second portion connected to the first portion on a rear side of the head, the second portion being located lower than the first portion via a stepped portion, the first portion including a face vicinity portion extending in a toe-heel direction along the face, and a heel vicinity portion connected to an end portion on a heel side of the face vicinity portion and extending to the rear of the head along a contour of the heel side of the crown, and in a plan view of the head, a length A in the front-to-rear direction of the head from the leading edge to an end portion on the rear side of the head of the heel vicinity is 70% or more of a maximum length B of the club head in the front-to-rear direction of the head.

[0007] In another aspect of the invention, in a plan view of the head, an area A2 of the second portion may be larger than an area A1 of the first portion.

[0008] In another aspect of the present invention, the ratio A2 / A1 of the areas A2 and A1 may be in the range of 1.5 to 3.0.

[0009] In another aspect of the present invention, the length of the heel vicinity in the toe-heel direction may be gradually decreased toward the rear of the head in a plan view of the head.

[0010] In another aspect of the present invention, the face has a face center, and in a planar view of the head, the step portion may include a first step portion extending in a toe-heel direction from the toe side toward the heel side, and a second step portion smoothly curved at a first position on the heel side of the face center and extending toward the rear of the head.

[0011] In another aspect of the present invention, the first position may be located 15 mm or more toward the heel side from the face center in the toe-heel direction.

[0012] In another aspect of the present invention, a length C in the toe-heel direction between the first position and the toe end may be in the range of 60% to 90% of a maximum length D of the club head in the toe-heel direction.

[0013] In another aspect of the present invention, in a plan view of the head, the end portion on the rear side of the head of the heel vicinity may be located on the toe side of the first position in the toe-heel direction.

[0014] In another aspect of the present invention, the golf club further includes a sole forming a bottom surface of the head, the sole including a third portion and a fourth portion located behind the head of the third portion, and the third portion may bulge from the fourth portion via a step portion.

[0015] In another aspect of the invention, the third portion may be substantially continuous with the first portion in the tow.

[0016] In another aspect of the invention, the golf club head may be a fairway wood or a hybrid. Effect of the Invention

[0017] By adopting the above-mentioned configuration, the golf club head of the present invention can increase the air resistance acting on the heel side of the golf club head during the downswing, and can therefore suppress toe-down. [Brief description of the drawings]

[0018] [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] 2 is a side view of the golf club head of the present embodiment as viewed from the heel side. FIG. [Diagram 5]1 is a perspective view of a golf club head according to an embodiment of the present invention, seen from the front and heel side. [Figure 6] 1 is a perspective view of a golf club head according to an embodiment of the present invention, as viewed from the toe side. [Figure 7] 2 is a perspective view of the golf club head of the present embodiment as viewed from the rear heel side. FIG. [Figure 8] 3 is a partial cross-sectional view taken along line VIII-VIII in FIG. 2. [Figure 9] 13A and 13B are a front view and a cross-sectional view taken along line s1, respectively, for explaining the periphery of the face. [Figure 10] 1 is a diagram showing the trajectory of a golf club during a downswing. [Figure 11] 11(A) to 11(C) are front views of golf club heads 1A, 1B and 1C in FIG. 10 as viewed from the front in the swing direction. [Figure 12] 2 is a diagram illustrating forces acting on a golf club head during a swing. [Figure 13] FIG. 13 is a plan view of a golf club head according to another embodiment. [Figure 14] FIG. 2 is a front view of a golf club illustrating toe down during a swing. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In each embodiment, the same or common elements are given the same symbols, and duplicate explanations are omitted.

[0020] 1 to 4 are respectively a plan view, a front view, a side view seen from the toe side, and a side view seen from the heel side of a golf club head (hereinafter simply referred to as "head") 1 of this embodiment. Furthermore, Figs. 5 to 7 are respectively a perspective view seen from the front and heel side, a perspective view seen from the rear and toe side, and a perspective view seen from the rear and heel side of the head 1 of this embodiment.

[0021] 1 to 7, the head 1 includes, for example, a face 2, a crown 3, a sole 4, a hosel 5, a toe T, and a heel H. In addition, in FIGS. 1 to 4, the head 1 is placed in a reference state described below.

[0022] [Reference condition] In this specification, the "reference state" of the head 1 is a state in which the head 1 is placed on a horizontal plane HP with a lie angle α (FIG. 2) and a loft angle (FIG. 3) set for the head 1. As shown in FIG. 3, in the reference 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 in a reference vertical plane VP perpendicular to the horizontal plane HP. In this specification, unless otherwise specified, the head 1 is in the reference state. The "shaft axis center line CL" is defined by the axis center line of the shaft insertion hole 5a formed in the hosel 5 of the head 1.

[0023] [Head Orientation] As shown in Figure 3, in the reference state of the head 1, the direction x 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. Moreover, the direction y parallel to both the reference vertical plane VP and the horizontal plane HP is defined as the toe-heel direction. Furthermore, the direction z perpendicular to the horizontal plane HP is defined as the up-down direction.

[0024] [Basic head structure] Fig. 8 is a cross-sectional view taken along line VIII-VIII in Fig. 2. As shown in Fig. 8, the head 1 of this embodiment is configured as, for example, a golf club head having a hollow portion i therein. Examples of this type of head include a wood type or a hybrid type.

[0025] The present invention is particularly suitable for use as a fairway wood or hybrid. These heads have, for example, a loft angle β of 13 to 35 degrees, a head weight of 200 g or more, and a head volume of 250 cc or less. The head 1 in Figs. 1 to 7 is shown as a fairway wood as a preferred embodiment.

[0026] 8, the face 2 includes a hitting face 2a, which is a surface for hitting a ball, and an inner face surface 2i, which faces the hollow portion i. The hitting face 2a has, for example, a bulge and a roll. As a result, the hitting face 2a is composed of a three-dimensional curved surface that is convex toward the outside.

[0027] The striking face 2a is defined by its periphery E. In this specification, the periphery E of the striking face 2a is defined as follows. First, as shown in Fig. 9(A), each cross section s1, s2, s3... including a normal line N connecting the head center of gravity CG and the sweet spot SS is identified. The sweet spot SS is the point where the normal line N drawn from the head center of gravity CG to the striking face 2a intersects with the striking face 2a.

[0028] Next, as shown in Figure 9(B), the position Pe where the radius of curvature r of the contour line Lf on the outer side of the head first reaches 200 mm from the sweet spot SS toward the outside of the face is determined for each cross section s1, s2, s3, etc., and the connecting of these positions Pe is defined as the periphery E of the hitting face 2a. The radius of curvature of any point on a curve is determined as the radius of a single circle that passes through three points: that point, a point 0.5 mm away on one side of that point, and a point 0.5 mm away on the other side of that point. These "0.5 mm" are the distance along the curve.

[0029] The striking face 2a also has a face center FC (see FIG. 1, etc.). In this specification, the "face center" FC is determined as follows. First, an arbitrary point P is selected that is approximately near the center of the striking face 2a in the vertical direction and the toe-heel direction. Next, a plane that passes through this point P, extends along the normal direction of the striking face 2a at the point P, and is parallel to the toe-heel direction is determined. A line of intersection between this plane and the striking face 2a is drawn, and its midpoint Px is determined. Next, a plane that passes through this midpoint Px, extends along the normal direction of the striking face 2a at the point Px, and is parallel to the vertical direction is determined. A line of intersection between this plane and the striking face 2a is drawn, and its midpoint Py is determined. Next, a plane that passes through this midpoint Py, extends along the normal direction of the striking face 2a at the point Py, and is parallel to the toe-heel direction is determined. A line of intersection between this plane and the striking face 2a is drawn, and its midpoint Px is newly determined. Next, a plane is determined that passes through the new midpoint Px, extends along the normal direction of the striking face 2a at the new midpoint Px, and is parallel to the up-down direction. A line of intersection between this plane and the striking face 2a is drawn, and its midpoint Py is determined anew. This process is repeated to determine Px and Py in sequence. In the repetition of this process, the new position Py (last position Py) at which the distance between the new midpoint Py and the previous midpoint Py becomes 0.5 mm or less for the first time is determined as the face center FC.

[0030] The hitting face 2a is provided with a plurality of grooves called face lines which extend in the toe-heel direction, but these are omitted from the drawings of this embodiment.

[0031] The crown 3 extends from the face 2 toward the rear of the head so as to form the top surface of the head. The crown 3 is, for example, a portion visible in a plan view of the head excluding the face 2. A hosel 5 is provided on the heel side of the crown 3. The hosel 5 is formed with a shaft insertion hole 5a for fixing a club shaft (not shown).

[0032] The sole 4 extends from the face 2 to the rear of the head so as to form the bottom surface of the head. The sole 4 is, for example, a portion that is visible in a bottom view of the head.

[0033] The head 1 is mainly made of, for example, a metal material. The metal material is not particularly limited, but may be, for example, pure titanium, titanium alloy, stainless steel, maraging steel, aluminum alloy, magnesium alloy, tungsten-nickel alloy, etc. A part of the head 1 (for example, the crown 3) may be made of a non-metallic material such as fiber-reinforced resin.

[0034] [Crown Features] 1, the crown 3 includes a first portion 31 adjacent to the face 2, and a second portion 32 continuing to the head rear side of the first portion 31. In this embodiment, both the first portion 31 and the second portion 32 have outer surfaces that are smoothly convex toward the head outer surface side, but the second portion 32 is located lower than the first portion 31 via a step portion 6.

[0035] The step portion 6 of this embodiment includes a front edge 6a located on the face 2 side and a rear edge 6b located behind the front edge 6a. As shown in Fig. 8, the step portion 6 of this embodiment is formed with a slope that descends from the front edge 6a to the rear edge 6b.

[0036] In the head 1 of the present embodiment, the first portion 31 also includes a face proximate portion 311 and a heel proximate portion 312 .

[0037] The face vicinity 311 is a portion of the first portion 31 that extends in the toe-heel direction along the face 2. The heel vicinity 312 is a portion of the first portion 31 that is continuous with the heel side end of the face vicinity 311 and extends toward the rear of the head along the heel side contour of the crown 3. Therefore, both the face vicinity 311 and the heel vicinity 312 are located higher than the second portion 32 and protrude from the second portion 32 via the step portion 6.

[0038] In addition, in this embodiment, in a plan view of the head shown in Figure 1, the length A in the front-to-rear direction of the head from the leading edge Le to the end 312e on the rear side of the head of the heel vicinity 312 is set to be 70% or more of the maximum length B of the club head in the front-to-rear direction of the head.

[0039] [Function 1 of this embodiment] Since the first portion 31 adjacent to the face 2 is located above the second portion 32 at the rear of the head via the step portion 6, the area of ​​the face 2 (particularly, the vertical dimension) is maintained larger, and the repulsion performance of the face 2 is maintained or improved. Such a face 2 is useful for increasing the initial velocity of a hit ball, for example. In a preferred embodiment, as shown in FIG. 2, the maximum vertical length 2H of the face 2 can be enlarged to 23 mm or more, more preferably 26 mm or more. Similarly, the maximum vertical length 1H of the head 1 can be enlarged to, for example, 30 mm or more, more preferably 35 mm or more.

[0040] In addition, the second portion 32, which is located further rearward than the first portion 31, is located lower than the first portion 31 via the step portion 6, providing a low head center of gravity CG. Such a head 1 is useful for reducing the amount of backspin on a hit ball. In a preferred embodiment, the center of gravity height CGH, which is the height of the head center of gravity CG (shown in FIG. 2) from the horizontal plane HP, may be, for example, 20 mm or less, more preferably 17 mm or less.

[0041] In a preferred embodiment, as shown in Fig. 1, the area A2 of the second portion 32 is desirably larger than the area A1 of the first portion 31 in a plan view of the head. This allows the head center of gravity CG to be located at an even lower position. Here, the area A2 of the second portion 32 is the area surrounded by the head contour line and the rear edge 6b of the step portion 6. Moreover, the area A1 of the first portion 31 is the area A1 (including the hosel 5) surrounded by the head contour line, the front edge 6a of the step portion 6, and the periphery E of the face 2.

[0042] In a particularly preferred embodiment, the ratio A2 / A1 of the areas A2 and A1 is preferably in the range of 1.5 to 3.0, for example. By specifying the ratio of the areas A1 and A2 of the first portion 31 and the second portion 32 in this manner, an increase in the area of ​​the face 2 and a lower center of gravity of the head can be achieved in a more balanced manner.

[0043] [Function 2 of this embodiment] Furthermore, the head 1 of this embodiment can suppress toe-down during the downswing. The mechanism of action is as follows.

[0044] Fig. 10 shows the trajectory of the head 1 during a typical downswing. This trajectory is seen from the front of a golfer (not shown) who has addressed the ball, and reference numeral 100 indicates the direction of travel of the head 1. Figs. 11(A) to (C) respectively show heads 1A, 1B and 1C during the swing trajectory of Fig. 10 as seen from the front in the swing direction.

[0045] As is clear from these figures, if the center SC of the swing trajectory is likened to the center of a clock, the face 2 of head 1A at approximately the 9 o'clock position faces almost directly forward. Head 1 then moves so that face 2 gradually closes (head 1B), and at impact the face 2 is completely closed (head 1C).

[0046] 11(A) and (B), during the downswing, the head 1 goes through a process of moving forward with the heel H side facing the swing direction. In particular, during the downswing, the head speed tends to accelerate rapidly during this process, so the surface of the heel H side of the head 1 receives a large air resistance.

[0047] FIG. 12 shows the forces acting on the head 1A at approximately the 9 o'clock position in FIG. 10. The head 1 is subjected to a centrifugal force F at the head center of gravity CG and air resistance f on the heel H side. The symbol BL is an axis extending to the center of rotation of the golf club head. The centrifugal force F generates a rotational moment M that moves the head 1 in a direction (while bending the shaft 10) such that the head center of gravity CG approaches the shaft axis center line CL. This results in toe-down. On the other hand, the air resistance f acts against the toe-down of the head 1.

[0048] The head 1 of this embodiment increases the projected area of ​​the head 1 as viewed from the heel H side, thereby actively increasing the air resistance f during the downswing. That is, by providing the heel vicinity 312, the projected area of ​​the head 1 as viewed from the heel H side perpendicular to the shaft axis center line CL along the reference vertical plane VP (the projected area as viewed from XII-XII in FIG. 12, which is shown in FIG. 11(A)) becomes larger than that of a head not provided with the heel vicinity 312. Since the air resistance f is proportional to the projected area of ​​the head 1, the head 1 of this embodiment experiences a large air resistance f from approximately the 9 o'clock position during the downswing and thereafter, and thus can effectively suppress the toe-down of the head 1 during the downswing.

[0049] 1 to the end 312e on the rear side of the heel vicinity 312 is less than 70% of the maximum club head length B in the front-rear direction, the projected area cannot be increased sufficiently, and the toe-down suppression effect cannot be obtained sufficiently. Preferably, the length A is 80% or more of the maximum club head length B.

[0050] More preferred specific embodiments will be described below.

[0051] [Near Face] In order to maintain or increase the area of ​​the face 2, it is desirable that the face vicinity 311 of the first portion 31 is formed sufficiently long in the toe-heel direction. For example, in the plan view of the head in FIG. 1, it is desirable that the face vicinity 311 starts from the contour line of the toe T of the head 1 and extends to the heel H side. Even in this case, it is desirable that the face vicinity 311 does not protrude to the toe side as shown in FIG. 1. Thereby, the contour line on the toe T side of the head 1 can be formed as a smooth arc-shaped curve that is convex to the toe side without unevenness. In another aspect, the face vicinity 311 may be formed so as to start in the vicinity of the contour line of the toe T of the head 1 (for example, within 10 mm on the heel H side).

[0052] The first portion 31 of this embodiment extends to the heel H. That is, as can be seen from Figs. 4 to 7, the heel H side of the first portion 31 is located above a surface obtained by virtually extending the second portion 32 along its surface. Therefore, the face vicinity 311 of this embodiment also extends substantially to the heel H. In this embodiment, since the face vicinity 311 is formed over the entire range of the face 2 in the toe-heel direction, the area of ​​the face 2 is effectively increased, and the repulsion performance of the face 2 can be further improved.

[0053] 1, the front-rear width W1 of the face vicinity 311 is not particularly limited, but from the viewpoint of improving the repulsion performance of the face 2, it may be, for example, 5% or more, preferably 10% or more, and more preferably 15% or more of the maximum club head length B. From the viewpoint of providing a low head center of gravity height CGH, the front-rear width W1 of the face vicinity 311 may be, for example, 45% or less, preferably 40% or less, and more preferably 35% or less of the maximum club head length B. The front-rear width W1 of the face vicinity 311 may be in the range of 5 to 25 mm.

[0054] [Area near the heel] 1, the heel vicinity 312 of this embodiment is formed as a region between the contour of the heel H side of the crown 3 and the front edge 6a of the step portion 6. In other words, the heel vicinity 312 defines the contour of the heel H side of the crown 3. Such a heel vicinity 312 effectively increases the projected area during the above-mentioned downswing.

[0055] The end 312e of the heel proximate portion 312 is located, for example, on the contour line of the crown 3. In another embodiment, the end 312e of the heel proximate portion 312 may be located in front of the contour line of the head 1.

[0056] In the plan view of the head in Fig. 1, it is desirable that the length W2 of the heel vicinity 312 in the toe-heel direction gradually decreases toward the rear of the head. In this embodiment, the length W2 of the heel vicinity 312 continuously decreases from the face vicinity 311 to the end 312e of the heel vicinity 312, and is zero at the end 312e. This aspect helps to prevent the center of gravity CG of the head from becoming high.

[0057] [Step] The step portion 6 in this embodiment extends from the contour line of the crown 3 on the toe T side to the heel H side, and curves toward the rear of the head at the heel H side to extend to the contour line on the back side of the crown 3. More specifically, the step portion 6 includes a first step portion 61 extending in the toe-heel direction, and a second step portion 62 that smoothly curves toward the rear of the head at a first position P1 on the heel H side of the face center FC and extends in the front-rear direction. Therefore, the first step portion 61 separates the second portion 32 from the face vicinity 311. Moreover, the second step portion 62 separates the second portion 32 from the heel vicinity 312.

[0058] The first step portion 61 extends, for example, approximately parallel to the periphery E (upper edge) of the face 2 to a first position P1. In a preferred embodiment, the first position P1 is located, for example, 15 mm or more, more preferably 18 mm or more toward the heel H side from the face center FC in the toe-heel direction. This ensures a large area for the second portion 32, and thus a lower head center of gravity height CGH can be provided. In addition, the face vicinity portion 311 is formed large in the toe-heel direction, and thus the repulsion performance of the face 2 can be further improved.

[0059] As another method of specification, the length C in the toe-heel direction between the first position P1 and the toe end Te may be, for example, 60% or more, more preferably 65% ​​or more, and even more preferably 70% or more of the maximum length D of the club head in the toe-heel direction. The maximum length D of the club head in the toe-heel direction is defined as the horizontal distance between the toe end Te that protrudes most toward the toe side and the heel point Hd at a height of 22.23 mm from the horizontal plane in a front view of the head 1 in the reference state, as shown in Fig. 2. The length C in the toe-heel direction between the first position P1 and the toe end Te is specified in a plan view of the head 1 in the reference state, as shown in Fig. 1.

[0060] In a more preferred embodiment, the first position may be located closer to the heel H in the toe-heel direction than the end 312e of the heel proximate portion 312. According to such an embodiment, the area of ​​the second portion 32 can be increased while ensuring the large air resistance described above, and thus a lower height CGH of the center of gravity of the head can be provided.

[0061] The second step portion 62 starts to curve from the first position P1 and extends toward the rear of the head along the heel side contour of the head 1. The second step portion 62 in this embodiment has a smooth arc shape.

[0062] As shown in Fig. 8, the height h of the step 6 in the vertical direction between the front edge 6a and the rear edge 6b may be, for example, 1.0 mm or more, more preferably 1.5 mm or more, and even more preferably 2.0 mm or more. This allows the face vicinity 311 and the heel vicinity 312 to be located higher than the second portion 32, thereby further improving the repulsion performance of the face 2 and the effect of suppressing toe-down during the downswing. On the other hand, if the height h of the step 6 is excessively large, there is a risk that stress will be concentrated on the step 6 when hitting the ball. Under such circumstances, the height h of the step 6 may be, for example, 7.0 mm or less, preferably 6.5 mm or less, and even more preferably 6.0 mm or less.

[0063] The height h of the step portion 6 in this embodiment is formed to be substantially constant except for the end portion on the heel side. The height h of the step portion 6 may be gradually decreased at the end portion on the heel side. In another embodiment, the height h of the step portion 6 may be different at each portion. For example, the height of the second step portion 62 may be formed to be greater than the height of the first step portion 61. This makes it possible to effectively increase the projected area of ​​the head as viewed from the heel side.

[0064] In FIG. 1, the width of the step portion 6, which is the distance between the front edge 6a and the rear edge 6b of the step portion 6, is not particularly limited, and may be, for example, 1.0 mm or more, more preferably 1.5 mm or more, and even more preferably 2.0 mm or more, and may be, for example, 7.0 mm or less, preferably 6.5 mm or less, and even more preferably 6.0 mm or less.

[0065] [Sole] 3, the sole 4 may include a third portion 43 and a fourth portion 44 located behind the third portion. The third portion 43 may bulge from the fourth portion 44 via a step portion 60. Such a head 1 also helps to maintain or increase the area of ​​the face 2. In this embodiment, the third portion 43 is formed so as to be substantially continuous with the first portion 31 at the toe T.

[0066] [Other head shapes] Fig. 13 shows a plan view of a head 1 according to another embodiment of the present invention. In Fig. 13, the head 1 is implemented as a hybrid. As described above, the present invention can be implemented in various forms.

[0067] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above specific disclosure, and can be implemented in various modified forms within the scope of the technical ideas described in the claims. EXAMPLES

[0068] More specific, non-limiting examples of the present invention will now be described. A hollow fairway wood having the basic structure shown in Figs. 1-7 was prototyped based on the specifications in Table 1, and the height CGH of the head center of gravity was measured. In addition, aerodynamic simulation using a computer was used to calculate the drag that correlates with the air resistance that the head experiences during the downswing. This drag is a force perpendicular to the paper surface that the head in the state of Fig. 11(B) (head speed 30 m / s) experiences, and the larger the value, the greater the effect of suppressing toe-down. For comparison, the crown is provided with a first portion, a second portion, and a step between them, but the same measurements and calculations were also performed on a golf club head (comparative example) consisting of only the face vicinity portion, in which the first portion extends continuously in the toe-heel direction with a width W1. The results are shown in Table 1. In both the example and comparative example, the width W1 of the first portion was set to 16 mm.

[0069] [Table 1]

[0070] As can be seen from Table 1, the embodiment has a larger resistance during the downswing than the comparative example, and therefore it is possible to suppress toe-down. [Explanation of symbols]

[0071] 1. Golf club head 2 Face 3 Crowns 4 Sole 6, 60 Step 31 Part 1 32 Part 2 43 Part 3 44 Part 4 60 Step 61 First step 62 Second step 311 Near the face 312 Heel area 312e End of heel FC Face Center H heel Le Leading Edge P1 1st position T Toe

Claims

1. A golf club head, A face for striking the ball; and a crown forming an upper surface of the head; the crown includes a first portion adjacent to the face and a second portion continuing to a head rear side of the first portion, The second portion is located below the first portion via a step portion, the first portion includes a face proximate portion extending in a toe-heel direction along the face, and a heel proximate portion continuing to a heel side end of the face proximate portion and extending toward the rear of the head along a contour of the heel side of the crown, In a plan view of the head, a length A in the front-to-rear direction of the head from the leading edge to an end portion on the rear side of the head in the vicinity of the heel is 70% or more of a maximum length B of the club head in the front-to-rear direction of the head, the step portion includes a first step portion extending in a toe-heel direction from the toe side toward the heel side, and a second step portion smoothly curved toward the rear of the head at a first position on the heel side of the face center and extending in the front-to-rear direction, The height of the second step portion is greater than the height of the first step portion. Golf club head.

2. The golf club head according to claim 1 , wherein an area A2 of the second portion is larger than an area A1 of the first portion in a plan view of the head.

3. 3. The golf club head according to claim 2, wherein the ratio A2 / A1 of the areas A2 and A1 is in the range of 1.5 to 3.

0.

4. 4. The golf club head according to claim 1, wherein, in a plan view of the head, a length of the heel vicinity in a toe-heel direction continuously decreases from the face vicinity to the end portion of the heel vicinity.

5. A golf club head as described in any one of claims 1 to 4, wherein the first position is at least 15 mm heel side from the face center in the toe-heel direction.

6. A golf club head as described in any one of claims 1 to 5, wherein a length C in the toe-heel direction between the first position and the toe end is in the range of 60% to 90% of a maximum length D of the club head in the toe-heel direction.

7. A golf club head as described in any one of claims 1 to 6, wherein, in a planar view of the head, the end portion of the heel vicinity is located on the toe side of the first position in the toe-heel direction.

8. Further comprising a sole forming a bottom surface of the head, The sole includes a third portion and a fourth portion located behind the third portion, The third portion bulges from the fourth portion via a step portion, 8. The golf club head of claim 1, wherein the third portion is substantially contiguous with the first portion at a toe.

9. A golf club head as claimed in any one of claims 1 to 8, which is a fairway wood or a hybrid.

10. A golf club head as described in any one of claims 1 to 9, wherein the width W1 in the front-to-rear direction of the head near the face is greater than or equal to 5% and less than or equal to 45% of the maximum length B of the club head.

11. The step portion has a front edge located on the face side and a rear edge located behind the front edge, A vertical height h between the front edge and the rear edge is 2.0 mm or more and 7.0 mm or less, 8. The golf club head according to claim 1, wherein a width of the step portion, which is a distance between the front edge and the rear edge in a plan view of the head, is 1.0 mm or more and 7.0 mm or less.

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