Golf club head

Abstract

To expand a high rebound area of a face part while keeping durability of a head by reducing stress in the face part on the side of a sole.SOLUTION: A golf club head comprises a face part. The face part includes a face front surface that is a surface for hitting a ball, a face back surface 22, and a face center. A center thin part 50, a sole side thin part 60 extending in a toe-heel direction so as to be closer to the side of a sole 4 than the center thin part 50, and a sole side rib 70 extending in the toe-heel direction between the center thin part 50 and the sole side thin part 60 are formed in the face back surface 22. In a head vertical cross section passing through the face center, a width W1 of the sole side thin part is larger than a width W2 of the sole side rib 70.SELECTED DRAWING: Figure 6

Description

[Technical Field]

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

[0002] BACKGROUND ART Various golf club heads have been proposed in which a thin portion having a small thickness is formed in the central region of the face portion that strikes the ball (for example, see Patent Document 1 below). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-036052 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0004] In recent years, attempts have been made to expand the high-repulsion area, which allows the ball to travel further, by increasing the area of ​​the thin-walled portion of the face. However, simply expanding the thin-walled portion toward the sole of the face can cause large stresses on the sole of the face when hitting a ball, which can lead to damage to the face and other problems that could reduce its durability.

[0005] The present disclosure has been devised in consideration of the above-described circumstances, and its main object is to provide a golf club head that can expand the high-repulsion area of ​​the face while maintaining the durability of the head. [Means for solving the problem]

[0006] The present disclosure relates to a golf club head, which comprises a face portion and a sole in a standard state where the face portion is placed on a horizontal plane with a specified lie angle and loft angle, the face portion including a face front which is the surface that strikes a ball, a face back surface, and a face center, the face back surface having a central thin portion, one or more sole-side thin portions extending in a toe-heel direction on the sole side of the central thin portion, and a sole-side rib extending in a toe-heel direction between the central thin portion and the sole-side thin portion closest to the central thin portion, the golf club head having a width W1 of the sole-side thin portion measured parallel to the face front surface in a head longitudinal section that passes through the face center and is perpendicular to the face front surface and the horizontal plane, which is greater than a width W2 of the sole-side rib measured parallel to the face front surface. [Effects of the Invention]

[0007] By adopting the above-described configuration, the golf club head of the present disclosure can expand the high-rebound area of ​​the face portion while maintaining the durability of the head by reducing the stress on the sole side of the face portion that occurs when hitting a ball. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a front view of the golf club head of the present embodiment. [Figure 2] FIG. 2 is a rear view of the golf club head of the present embodiment. [Figure 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. 2 is a perspective view illustrating a reference state of the golf club head. [Figure 5] FIG. 10 is a front view of a golf club head showing a modified example of the face line. [Figure 6] FIG. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 6. [Figure 8] FIG. 8 is a partial enlarged view of the sole side of FIG. 7. [Figure 9]FIG. 10 is a rear view of a face plate according to another embodiment. [Figure 10] 10 is a cross-sectional view taken along line XX in FIG. 9. [Figure 11] 4(A) to 4(D) are rear views of face plates of golf club heads of a comparative example and an example. [Figure 12] 10(A) to 10(C) are diagrams showing the distribution of stress acting on the face plates of Comparative Example 2, Example 1, and Example 2 when hitting a ball. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. Throughout this specification, the same or common elements are denoted by the same reference numerals, and redundant explanations will be omitted. Furthermore, the specific configurations shown in the embodiments and drawings are for the purpose of understanding the contents of the present disclosure, and the present disclosure is not limited to the specific configurations shown in the drawings.

[0010] 1 to 3 are a front view, a rear view, and a cross-sectional view taken along line III-III in FIG. 1, respectively, of a golf club head (hereinafter sometimes simply referred to as a "head") 1 according to this embodiment.

[0011] The head 1 of this embodiment is configured as, for example, an iron type made of a metal material. In other embodiments, the head 1 may be configured as a wood type or a utility type instead of an iron type.

[0012] 1 to 3, the head 1 is oriented in a reference state. In this specification, the "reference state" of the head 1 refers to a state in which the head 1 is placed on a horizontal plane with a specified lie angle α and loft angle β, as conceptually shown in FIG. 4, and the central axis CL of the hosel 7 of the head 1 (which corresponds to the axis of the club shaft) is located within the reference vertical plane VP. The lie angle α and loft angle β of the head 1 are usually listed in product catalogs, etc. In the reference state of an iron-type head 1, the head 1 is placed on a horizontal plane HP so that the face line 8 formed on the front face 21 is parallel to the horizontal plane HP. In this specification and claims, unless otherwise specified, the configuration of each part will be described assuming that the head 1 is placed in the reference state.

[0013] Also, with reference to Figure 4, the front side of the head 1 refers to the side of the face front surface 21. The rear or back side of the head 1 refers to the side of the face back surface 22. The front-to-rear direction of the head in Figure 4 is the direction of the x-axis, which is perpendicular to the reference vertical plane VP. The toe-heel direction of the head 1 is the direction of the horizontal y-axis, which is perpendicular to the front-to-rear direction of the head. The up-down direction of the head 1 is the direction of the z-axis, which is perpendicular to both the x-axis and y-axis. The "upper side" and "lower side" of the head 1 correspond to the "upper side" and "lower side" in the reference state, respectively.

[0014] 1 to 3, the head 1 includes a face portion 2. The face portion 2 includes a face front surface 21 which is the surface that strikes the ball, a face back surface 22 which is the surface opposite thereto, and a face center FC.

[0015] In this specification, the face center FC is defined as the central position of the face height (indicated by symbol H1 in FIGS. 6 and 7 ), which is the vertical dimension of the face front surface 21, at the central position C in the toe-heel direction of the face front surface 21, as shown in FIG. 1. In addition, in this specification, the central position C in the toe-heel direction of the face front surface 21 is defined as the central position in the toe-heel direction between the end point 8a of the face line 8 located at the most toe side and the end point 8b of the face line 8 located at the most heel side, as shown in FIG. 1. However, in the case of a head 1 in which the face line 8 extends beyond the highest position P1 of the top 3 to the vicinity of the toe 5, as shown in FIG. 5 , the central position in the toe-heel direction between the position 8c located 18 mm toward the heel from the most toe-side end of the face front surface 21 and the end point 8b of the face line 8 located at the most heel side is defined as the central position C in the toe-heel direction of the face front surface 21.

[0016] A plurality of face lines 8 are formed on the front face surface 21 in order to increase friction with the ball. Except for the face lines 8, the front face surface 21 is essentially formed as a flat surface. The face lines 8 in this embodiment are, for example, narrow grooves extending linearly in the toe-heel direction. The face lines 8 are formed in the main hitting area intended for the head 1. Note that the face lines 8 are omitted in some of the drawings.

[0017] The head 1 of this embodiment also includes a top 3, a sole 4, a toe 5, a heel 6, and a hosel .

[0018] 3, the top 3 extends from the upper edge of the face front surface 21 to the rear of the head 1 and constitutes the upper surface of the head 1. The sole 4 extends from the lower edge of the face front surface 21 to the rear of the head 1 and constitutes the lower surface of the head 1.

[0019] As shown in FIG. 1 , the toe 5 is the end portion of the head 1 that is farthest from the hosel 7 in the toe-heel direction, and smoothly connects the top 3 and the sole 4. The heel 6 is the end portion of the head 1 that is located on the opposite side from the toe 5 in the toe-heel direction, and the hosel 7 is connected to it.

[0020] 1, the hosel 7 has a shaft insertion hole 7a for receiving a club shaft (not shown). A central axis CL of the hosel 7 is defined by the central axis of the shaft insertion hole 7a.

[0021] 3, the head 1 of this embodiment is formed by joining a face plate 30 and a frame portion 40 that supports the face plate 30. The face plate 30 and the frame portion 40 are fixed to each other by various methods, such as welding, screwing, or caulking.

[0022] The face plate 30 includes, for example, a front face surface 21 and a back face surface 22, which will be described later.

[0023] As shown in FIG. 2, the frame portion 40 of this embodiment includes a top side frame 41, a sole side frame 42, a toe side frame 43, and a heel side frame 44.

[0024] The top-side frame 41 extends in the toe-heel direction along the top 3. The sole-side frame 42 extends in the toe-heel direction along the sole 4. The toe-side frame 43 and the heel-side frame 44 are formed on the toe 5 and the heel 6, respectively, and connect the top-side frame 41 and the sole-side frame 42. The frame portion 40 of this embodiment is formed in an annular shape so as to continuously support the outer peripheral edge of the face back surface 22. Furthermore, each of these frames 41, 42, and 43 has an outer peripheral surface exposed to the outer peripheral surface of the head.

[0025] As can be seen from Fig. 3, the head 1 of this embodiment has a face plate 30 fixed to the front surface of a frame portion 40. In this embodiment, the joint between the frame portion 40 and the face plate 30 is fixed by welding from the outer circumferential surface side of the head. The welded joint E can be formed, for example, at a depth of about 1.0 to 1.5 mm from the outer circumferential surface of the head.

[0026] Furthermore, the head 1 of this embodiment has a void space extending in the vertical direction of the head, i.e., a pocket-like cavity, formed between the face back surface 22 of the face plate 30 and the frame portion 40. In such a cavity-back head 1, more weight is distributed to the periphery of the face portion 2, increasing the moment of inertia around the center of gravity of the head. Therefore, the head 1 of this embodiment can suppress undesirable rotational movement of the face portion 2 even when the ball is struck at a position outside the sweet spot on the front face 21. This helps stabilize the directionality of the hit ball.

[0027] Fig. 6 shows a rear view of the face plate 30 before it is fixed to the frame portion 40. Fig. 7 shows a cross-sectional view taken along line VII-VII in Fig. 6. As shown in Figs. 6 and 7, the face plate 30 of this embodiment is formed in a plate shape having a reference thickness T, and includes a face front surface 21, a face back surface 22, and an outer peripheral surface 31 extending therebetween.

[0028] The reference thickness T refers to the thickness of the thickest portion of the face plate 30. The face plate 30 of this embodiment has a substantially constant reference thickness T, except for a thin portion, which will be described below. From the viewpoint of maintaining the durability of the face plate 30, this reference thickness T is preferably 2.0 mm or more, more preferably 2.3 mm or more, and even more preferably 2.5 mm or more, and is preferably 3.0 mm or less, more preferably 2.9 mm or less, and even more preferably 2.8 mm or less.

[0029] The outer peripheral surface 31 of the face plate 30 forms the front portion of the head of each of the top 3, sole 4, and toe 5, and is exposed on the outer peripheral surface of the head. In this embodiment, the heel side of the outer peripheral surface 31 is defined as a heel side surface 6a that extends vertically. The heel side surface 6a abuts against the frame portion 40 and is not exposed to the outside of the head. In FIG. 6, the deepest part of the joint E between the face plate 30 and the frame portion 40 is shown by a virtual line.

[0030] A central thin portion 50, a sole-side thin portion 60, and a sole-side rib 70 are formed on the face rear surface 22 of the face plate 30.

[0031] The central thin portion 50 of this embodiment is a recess formed on the back surface 22 side of the face. As a result, the central thin portion 50 is formed with a thickness tc that is smaller than the reference thickness T of the face plate 30.

[0032] The central thin portion 50 extends in the toe-heel direction and the head up-down direction, and has, for example, a contour shape that follows the contour shape of the outer peripheral surface 31 of the face plate 30. In this embodiment, the central thin portion 50 occupies the largest area among the thin portions formed on the face back surface 22. In a preferred embodiment, in a front view of the face back surface 22, the area of ​​the central thin portion 50 is 15% or more, more preferably 25% or more, and is preferably 60% or less, more preferably 50% or less of the total area of ​​the face back surface 22.

[0033] The central thin portion 50 is formed at a position including the face center FC in a front perspective view of the face back surface 22.

[0034] The sole-side thin portion 60 is a recess formed on the side of the face back surface 22. As a result, the sole-side thin portion 60 is formed with a thickness ts that is smaller than the reference thickness T of the face plate 30.

[0035] The sole-side thin portion 60 extends in the toe-heel direction on the side of the sole 4 (i.e., below) the central thin portion 50. In this example, the sole-side thin portion 60 is formed in the shape of a long, narrow groove in the toe-heel direction, and extends at an angle of ±5° or less with respect to the toe-heel direction. In this embodiment, one sole-side thin portion 60 is formed below the central thin portion 50. The sole-side thin portion 60 extends, for example, to cross a central position C in the toe-heel direction of the face front surface 21.

[0036] The sole-side rib 70 extends in the toe-heel direction between the central thin portion 50 and the sole-side thin portion 60. The thickness of the sole-side rib 70 is greater than the thicknesses tc and ts of the central thin portion 50 and the sole-side thin portion 60, respectively. The sole-side rib 70 in this embodiment is formed to have a thickness equal to the standard thickness T, but may be formed to have a thickness smaller than the standard thickness T.

[0037] 7 is a longitudinal cross-sectional view of the head (a longitudinal cross-sectional view of the face plate 30) that passes through the face center FC and is perpendicular to the face front surface 21 and the horizontal plane HP. As shown in FIG. 7, the width W1 of the sole-side thin portion 60 measured parallel to the face front surface 21 is larger than the width W2 of the sole-side rib 70 measured parallel to the face front surface 21.

[0038] The operation of the head 1 of this embodiment configured as above is as follows. A central thin portion 50 is provided on the back side of the main hitting area of ​​the face front surface 21, and a sole-side thin portion 60 is further provided below the central thin portion 50. These thin portions 50 and 60 allow the face plate 30 to bend significantly when hitting a ball. Such a face plate 30 expands the high-rebound area of ​​the face portion 2.

[0039] A sole-side rib 70 having a specified width W2 is interposed between the central thin portion 50 and the sole-side thin portion 60. Such a sole-side rib 70 appropriately absorbs the impact force when the ball is struck and transmits it to the sole-side thin portion 60. This reduces stress acting on the sole-side thin portion 60 of the face plate 30 and the position below it. Furthermore, because the width W1 of the sole-side thin portion 60 is formed larger than the width W2 of the sole-side rib 70, stress acting on the sole side of the face plate 30 is dispersed by deformation of the sole-side thin portion 60, eliminating local stress concentration at the joint E and the like. Furthermore, because the width W1 of the sole-side thin portion 60 is relatively small, the deflection of the face plate 30 when the ball is struck is not impaired, and a decrease in resilience performance is suppressed.

[0040] If the width W2 of the sole-side rib 70 is greater than the width W1 of the sole-side thin portion 60, the rigidity of the sole-side rib 70 and the area below it will be excessively increased. As a result, the impact force at the time of hitting the ball is transmitted to below the sole-side thin portion 60 via the sole-side rib 70 without being sufficiently absorbed. This is undesirable because it leads to local stress concentration at the joint E and the like.

[0041] The above-described relationship of width W1>W2 may be satisfied in the longitudinal section of the head shown in FIG. 7, but it is desirable that the relationship be satisfied within a range of 5 mm, further 10 mm, or further 15 mm on the toe side and heel side, centered on the longitudinal section of the head shown in FIG. 7.

[0042] From the viewpoint of further enhancing the stress dispersion effect on the sole 4 side when hitting a ball and more reliably suppressing a decrease in resilience performance, the ratio W1 / W2 of the width W1 of the sole-side thin portion 60 to the width W2 of the sole-side rib 70 is preferably 1.1 or more, and more preferably 1.3 or more. On the other hand, if the ratio W1 / W2 is excessively large, the above-mentioned function of the sole-side rib 70 may be impaired. From this viewpoint, the ratio W1 / W2 is preferably 3.0 or less, and more preferably 2.5 or less.

[0043] To further enhance the effect of dispersing stress on the sole side when hitting a ball, the width W1 of the sole-side thin portion 60 is preferably 3.8 mm or more, more preferably 4.1 mm or more, and even more preferably 4.4 mm or more. There is no particular upper limit to the width W1 of the sole-side thin portion 60, but it is set to, for example, 7.5 mm or less, preferably 7.0 mm or less, and more preferably 6.5 mm or less.

[0044] To more reliably prevent a decrease in resilience performance, the width W2 of the sole-side rib 70 is preferably 3.5 mm or less, more preferably 3.4 mm or less, and even more preferably 3.3 mm or less. There is no particular lower limit to the width W2 of the sole-side rib 70, but if it is too small, the durability of the head 1 may deteriorate, so the width W2 is preferably 1.0 mm or more, more preferably 1.5 mm or more, and even more preferably 2.0 mm or more.

[0045] It is desirable that the thickness ts of the sole-side thin portion 60 be smaller than the thickness tc of the central thin portion 50. This configuration maintains the strength near the center of the face, thereby maintaining the durability of the head 1, while further expanding the high-repulsion area of ​​the face portion 2.

[0046] The thickness ts of the sole side thin portion 60 is not particularly limited, but from the viewpoint of achieving both durability and a high-rebound area, it is preferably 0.9 mm or more, more preferably 1.0 mm or more, and even more preferably 1.1 mm or more, and is preferably 1.5 mm or less, more preferably 1.4 mm or less, and even more preferably 1.3 mm or less.

[0047] The thickness tc of the central thin portion 50 is not particularly limited, but from the viewpoint of achieving both durability and a high-resilience area, it is preferably 1.5 mm or more, more preferably 1.6 mm or more, and even more preferably 1.7 mm or more, and is preferably 2.5 mm or less, more preferably 2.4 mm or less, and even more preferably 2.3 mm or less.

[0048] The ratio tc / ts of the thickness ts of the sole-side thin portion 60 to the thickness tc of the central thin portion 50 is preferably in the range of 1.2 to 3.0, for example, which allows a good balance between the durability of the head 1 and the effect of expanding the high-resilience area.

[0049] In addition, when the thicknesses tc and ts of the sole-side thin portion 60 and / or the central thin portion 50 change, the application of the above-mentioned provisions is determined as the average thickness weighted by the occupied area in each thin portion.

[0050] The thickness tc of the central thin portion 50 may be constant, but is preferably formed so as to become thinner, for example, from the toe 5 side toward the heel 6 side. In this embodiment, the thickness tc of the central thin portion 50 becomes continuously thinner from the toe 5 side toward the heel 6 side. This configuration relatively improves the resilience performance on the heel 6 side in the region of the central thin portion 50. Empirically, the main impact position of average golfers tends to be more distributed slightly toward the heel 6 side than the face center FC. Therefore, by relatively improving the resilience performance on the heel 6 side in the central thin portion 50, the flight distance of the ball can be further improved.

[0051] In this embodiment, as shown in FIG. 7, in a longitudinal section of the head passing through the face center FC and perpendicular to the face front surface 21 and the horizontal plane HP, when the face height parallel to the face front surface 21 is H1 and the distance parallel to the face front surface 21 from the face center FC to the width center position of the sole-side rib 70 is H2, the ratio H2 / H1 is 0.20 to 0.41.

[0052] Thus, by setting the ratio H2 / H1 in the range of 0.20 to 0.41, the above-mentioned effect is more effectively exhibited. That is, when the ratio H2 / H1 is 0.20 or more, the position of the sole-side rib 70 is not excessively close to the face center FC, and the effect of expanding the high-repulsion area can be sufficiently achieved. Furthermore, by keeping the ratio H2 / H1 at 0.41 or less, the position of the sole-side rib 70 is not excessively close to the sole 4. As a result, stress concentration on the sole side of the face plate 30 when hitting a ball can be more reliably suppressed.

[0053] In order to expand the high-resilience area while maintaining the durability of the head 1, the ratio H2 / H1 is more preferably 0.25 or more, even more preferably 0.30 or more, and more preferably 0.40 or less, even more preferably 0.39 or less.

[0054] The sole-side thin portion 60 is desirably formed, for example, in the toe-heel direction within a face line forming range in which the face line 8 is formed. In other words, the sole-side thin portion 60 is desirably formed so as to be contained between an end point 8a of the face line 8 located closest to the toe side and an end point 8b of the face line 8 located closest to the heel side in the toe-heel direction.

[0055] Fig. 8 is a partially enlarged view of the sole 4 side of Fig. 7. As shown in Fig. 8, the sole-side thin portion 60 of this embodiment is a groove-shaped recess, and includes a bottom surface 61, side surfaces 62, 62, and arcuate surfaces 63, 63 that smoothly connect these surfaces.

[0056] In this embodiment, the bottom surface 61 is formed as a plane extending substantially parallel to the face front surface 21. The side surface 62 is formed as a plane substantially perpendicular to the face front surface 21. Here, the expression "substantially" above means that manufacturing errors are allowed, and specifically, an error of ±5° from a reference plane is allowed.

[0057] The arcuate surface 63 preferably has a radius of curvature r1 of 1.0 to 2.0 mm. When hitting a ball, stress tends to concentrate at the corner where the bottom surface 61 and side surface 62 of the sole-side thin portion 60 intersect, but by providing the arcuate surface 63 with the above-mentioned radius of curvature r1, the stress concentration at the corner of the sole-side thin portion 60 is alleviated, and ultimately the durability of the face portion 2 is further improved.

[0058] If the radius of curvature r1 of the arcuate surface 63 is less than 1.0 mm, the above-mentioned stress concentration relief effect may not be sufficiently achieved. Conversely, if the radius of curvature r1 of the arcuate surface 63 is more than 2.0 mm, the arcuate surface 63 may tend to suppress the deflection of the sole-side thin portion 60, which may hinder improvement in resilience performance.

[0059] Similarly, the central thin portion 50 of this embodiment includes a bottom surface 51, a side surface 52 surrounding the bottom surface 51, and an arcuate surface 53 smoothly connecting these surfaces.

[0060] In this embodiment, the bottom surface 51 is formed as a plane extending substantially parallel to the face front surface 21. The pair of side surfaces 52 are formed as planes substantially perpendicular to the face front surface 21. The word "substantially" is used here for the reasons described above.

[0061] Arc surface 53 preferably has a radius of curvature r2 of 1.0 to 2.0 mm. When hitting a ball, stress tends to concentrate at the corner where bottom surface 51 and side surface 52 of central thin portion 50 intersect, but by providing arc surface 53 with the above-mentioned radius of curvature r2, stress concentration at the corner of central thin portion 50 is alleviated, and ultimately the durability of face portion 2 is further improved.

[0062] Returning to FIG. 6, the face plate 30 of this embodiment further has a toe-side thin portion 80 and / or a top-side thin portion 90 formed on the back surface 22 of the face.

[0063] The toe-side thin portion 80 is a recess formed on the face back surface 22 side. As a result, the toe-side thin portion 80 is formed with a thickness te (not shown) that is smaller than the reference thickness T of the face plate 30.

[0064] The toe-side thin portion 80 is disposed on the toe 5 side at a distance from the central thin portion 50. In this embodiment, the toe-side thin portion 80 extends so as to curve in an arc along the contour of the toe 5 side of the face plate 30. Such a toe-side thin portion 80 makes the toe side of the face portion 2 more flexible, and thus helps to expand the high-repulsion area toward the toe side.

[0065] In this embodiment, the thickness te of the toe-side thin portion 80 is smaller than the thickness tc of the central thin portion 50. When formed in this manner, the stress on the toe 5 side of the face portion 2 that occurs when hitting a ball is reduced, maintaining the durability of the head 1, while also allowing the high-repulsion area of ​​the face portion 2 to extend toward the toe 5.

[0066] The top-side thin portion 90 is a recess formed on the face back surface 22 side. As a result, the top-side thin portion 90 is formed with a thickness tt that is smaller than the reference thickness T of the face plate 30.

[0067] The top-side thin portion 90 is disposed on the top 3 side at a distance from the central thin portion 50. In this embodiment, the top-side thin portion 90 extends along the contour of the top 3 side of the face plate 30. Such a top-side thin portion 90 makes the top 3 side of the face portion 2 more flexible, and thus helps to expand the high-repulsion area toward the top 3 side.

[0068] In this embodiment, the thickness tt of the top-side thin portion 90 is smaller than the thickness tc of the central thin portion 50. When formed in this manner, the stress on the top 3 side of the face portion 2 that occurs when hitting a ball is reduced, maintaining the durability of the head, while also allowing the high-repulsion area of ​​the face portion 2 to extend toward the top 3 side.

[0069] In a preferred embodiment, the thickness te of the toe-side thin portion 80 may be smaller than the thickness tt of the top-side thin portion 90. In such an embodiment, the high-rebound area of ​​the face portion 2 can be expanded in the toe-heel direction.

[0070] The thickness te of the toe-side thin portion 80 is not particularly limited, but in order to expand the high-rebound area in the toe-heel direction while maintaining the durability of the face portion 2, it is preferably 0.6 mm or more, more preferably 0.7 mm or more, even more preferably 0.8 mm or more, and is preferably 1.3 mm or less, more preferably 1.2 mm or less, even more preferably 1.1 mm or less.

[0071] The thickness tt of the top-side thin portion 90 is not particularly limited, but in order to expand the high-rebound area in the vertical direction while maintaining the durability of the face portion 2, it is preferably 1.1 mm or more, more preferably 1.2 mm or more, even more preferably 1.3 mm or more, and is preferably 1.8 mm or less, more preferably 1.7 mm or less, even more preferably 1.6 mm or less.

[0072] [Other embodiments] 9 and 10 show yet another embodiment of the present disclosure. FIG. 9 is a rear view of the face plate 30 (i.e., a view of the face rear surface 22 viewed from a direction perpendicular to the face front surface 21). FIG. 10 is a cross-sectional view taken along line XX in FIG. 9. As shown in FIGS. 9 and 10, this embodiment differs from the previous embodiment in that the face plate 30 has a plurality of (two in this example) sole-side thin portions 60, 60 formed at intervals in the vertical direction of the head. This embodiment, like the previous embodiment, also achieves the effect of reducing stress on the sole 4 side of the face portion 2 generated when hitting a ball, thereby maintaining the durability of the head 1, while also expanding the high-repulsion area of ​​the face portion 2 in the vertical direction.

[0073] In this embodiment, the width W1 of the above-mentioned sole-side thin portion 60 measured parallel to the face front surface 21 is defined as the total width obtained by adding up the widths W1a and W1b of all of the sole-side thin portions 60, 60. The width W2 of the sole-side rib 70 is defined as the width of the rib portion extending in the toe-heel direction between the central thin portion 50 and the single sole-side thin portion 60 closest to the central thin portion 50 (i.e., the upper sole-side thin portion 60).

[0074] 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 idea described in the claims. [Example]

[0075] More specific, non-limiting examples of the present disclosure are described below. A computer simulation model of an iron-type golf club head with the basic structure shown in Figures 1 to 10 was designed based on the specifications in Table 1. In each model, the face plate and frame were integrated with the frame within a range of 1.5 mm from the outer periphery of the face plate to the inside of the head in order to reproduce a state of fastening by welding. The back surface shape of each face plate is as shown in Figures 11(A) to 11(D).

[0076] Next, calculations were performed on durability and resilience performance using each model. Durability was evaluated based on the results of an impact simulation in which a ball was impacted with the center of the face of each model. The impact simulation output the stress at the face center and the maximum stress generated on the sole side of the face. The results are expressed as an index, with the stress value of Comparative Example 1 being 100, and the smaller the number, the better.

[0077] The resilience performance was evaluated by the COR value. COR stands for Coefficient of Restitution and was calculated in accordance with the "Interim Procedure for Measuring the Coefficient of Restitution of an Iron Clubhead Relative to a Baseline Plate Revision 1.3 January 1, 2006" prescribed by the USGA (United States Golf Association). In this example, the COR was calculated at 5-mm intervals in a range of 15 mm above the face center, 5 mm below the face center, and 30 mm in the toe-heel direction from the face center when viewed from the front of the face.

[0078] Table 1 shows the specifications and durability calculation results of the golf club head models of the examples and comparative examples. Also, Figures 12(A) to 12(C) are diagrams showing the stress distribution acting on the face plate at the moment when the maximum stress was generated in the impact simulation for the representative examples of Comparative Example 2, Example 1, and Example 2.

[0079] [Table 1]

[0080] As is clear from Table 1, the stress at the face center of the head was reduced by approximately 8% or more in the example compared to the comparative example. Also, the maximum stress generated on the sole side of the face was reduced by approximately 25% or more in the example compared to the comparative example.

[0081] 12(A) , Comparative Example 2 (in which the width of the sole-side rib is greater than the width of the sole-side thin portion) has a darker hue over a wide area, surrounded by dashed lines, in the face center, the sole-side end of the face plate, and the heel side of the sole-side rib. This indicates that high stress is occurring over a wide area. In contrast, in Examples 1 and 2, the area corresponding to the dashed line area in Comparative Example 2 has a slightly lighter hue and a smaller area, confirming that stress is reduced.

[0082] As representative examples of resilience performance, Tables 2 to 4 show COR distribution charts for Comparative Example 2 and Examples 1 and 2. In Tables 2 to 4, the upper row shows the COR value, and the lower row shows the COR retention rate at each position when the maximum COR is set to 100 (the higher the number, the better). The horizontal axis of each table represents the distance from the center of the face in the toe-heel direction, with + representing the heel side and - representing the toe side. The vertical axis of each table represents the distance from the center of the face in the up-down direction, with + representing the top side and - representing the sole side.

[0083] [Table 2]

[0084] [Table 3]

[0085] [Table 4]

[0086] As is clear from Tables 2 to 4, it was confirmed that the high-repulsion area was expanded in the Examples. A more detailed analysis follows. First, we focus on the COR retention in the area ±5 mm above and below, and ±10 mm to the left and right of the face center, which is the area with a high probability of impact with a ball when hitting a ball placed on the ground. In the Comparative Example, the average COR retention in this area was 91.5%, while in Examples 1 and 2, it was 91.8% and 91.9%, respectively, which were higher than the Comparative Example. It was also confirmed that the difference between the maximum and minimum COR retention within this area was more than two percentage points smaller in Examples 1 and 2 than in the Comparative Example. If we assume that the repulsion performance is directly linked to the flight distance when the ball spin and launch angle are the same, it is estimated that the variation in flight distance in Examples 1 and 2 is improved by more than three yards compared to the Comparative Example. Furthermore, when focusing on the area ±5 mm from the center of the face, which is an area where advanced golfers are particularly likely to hit the ball, the COR maintenance rate of Example 1 is 97.9%, which is thought to show an even more significant performance difference compared to the comparative example.

[0087] [Note] The present disclosure includes the following aspects.

[0088] [Disclosure 1] A golf club head, In a standard state where the club is placed on a horizontal plane with a specified lie angle and loft angle, the club has a face portion and a sole, the face portion includes a face front surface that is a surface for striking a ball, a face back surface, and a face center; a central thin portion, one or more sole-side thin portions extending in a toe-heel direction on the sole side of the central thin portion, and a sole-side rib extending in a toe-heel direction between the central thin portion and the sole-side thin portion closest to the central thin portion, In a head longitudinal section that passes through the face center and is perpendicular to the face front surface and the horizontal plane, a width W1 of the sole-side thin portion measured parallel to the face front surface is larger than a width W2 of the sole-side rib measured parallel to the face front surface. Golf club head. [Disclosure 2] The golf club head according to Disclosure 1, wherein the ratio W1 / W2 of the widths W1 and W2 is 1.1 or greater. [Disclosure 3] The golf club head according to Disclosure 1 or 2, wherein the width W1 of the sole-side thin portion is 3.8 mm or more. [Disclosure 4] The golf club head according to any one of Disclosures 1 to 3, wherein the width W2 of the sole-side rib is 3.5 mm or less. [Disclosure 5] The golf club head according to any one of Disclosures 1 to 4, wherein the thickness of the sole-side thin portion is smaller than the thickness of the central thin portion. [Disclosure 6] A golf club head according to any one of Disclosures 1 to 5, wherein, in the head longitudinal section, when the face height parallel to the face front surface is H1 and the distance parallel to the face front surface from the face center to the width center position of the sole-side rib is H2, the ratio H2 / H1 is 0.20 to 0.41. [Disclosure 7] A face line extending in a toe-heel direction is formed on the front of the face, The golf club head according to any one of Disclosures 1 to 6, wherein the sole-side thin portion is formed within a face line forming range in which the face line is formed in the toe-heel direction. [Disclosure 8] The golf club head according to any one of Disclosures 1 to 7, wherein the thickness of the central thin portion is formed to become thinner from the toe side toward the heel side. [Disclosure 9] A golf club head according to any one of Disclosures 1 to 8, wherein the sole-side thin portion includes a bottom surface, a side surface, and an arcuate surface smoothly connecting these surfaces, and the arcuate surface has a radius of curvature of 1.0 to 2.0 mm. [Disclosure 10] A golf club head according to any one of Disclosures 1 to 9, wherein the thickness of the central thin portion is 1.5 to 2.5 mm, the thickness of the sole side thin portion is 0.9 to 1.5 mm, and the thickness of the sole side rib is 2.0 to 3.0 mm. [Disclosure 11] The golf club head according to any one of Disclosures 1 to 10, which is an iron type. [Explanation of symbols]

[0089] 1 golf club head 2 Face section 4 Sole 5 Tou 6 Heel 8. Face Line 21 Front of face 22 Back of face 50 Central thin section 51 bottom 52 Side 53 Arc Surface 60 Thin part of sole 61 bottom 62 Side 63 Arc Surface 70 Sole side rib FC face center HP horizontal plane

Claims

1. A golf club head, In a standard state where the club is placed on a horizontal plane with a specified lie angle and loft angle, the club has a face portion and a sole, the face portion includes a face front surface that is a surface for striking a ball, a face back surface, and a face center, A face line extending in a toe-heel direction is formed on the front surface of the face, a central thin portion; one or more sole-side thin portions extending in a toe-heel direction on the sole side of the central thin portion; and a sole-side rib extending in a toe-heel direction between the central thin portion and the sole-side thin portion closest to the central thin portion, the face center is a middle position of a face height, which is a vertical dimension of the face front surface, at a central position of the face front surface in a toe-heel direction, The central position of the face front surface in the toe-heel direction is the central position in the toe-heel direction between the end point of the face line located closest to the toe side and the end point of the face line located closest to the heel side, or, in the case of a head in which the face line extends beyond the highest position of the top to the vicinity of the toe, the central position in the toe-heel direction is the central position between a position of the face front surface that is spaced 18 mm from the end closest to the toe side toward the heel side and the end point of the face line located closest to the heel side. In a head longitudinal section that passes through the face center and is perpendicular to the face front surface and the horizontal plane, a width W1 of the sole-side thin portion measured parallel to the face front surface is larger than a width W2 of the sole-side rib measured parallel to the face front surface, The thickness of the central thin portion is formed to become thinner from the toe side toward the heel side. Golf club head.

2. 2. The golf club head according to claim 1, wherein a ratio W1 / W2 of the widths W1 and W2 is 1.1 or greater.

3. 3. The golf club head according to claim 1, wherein the width W1 of the sole-side thin portion is 3.8 mm or more.

4. 4. The golf club head according to claim 1, wherein the width W2 of the sole-side rib is 3.5 mm or less.

5. 5. The golf club head according to claim 1, wherein the thickness of the sole-side thin portion is smaller than the thickness of the central thin portion.

6. 6. The golf club head according to claim 1, wherein, in the longitudinal section of the head, when a face height parallel to the front surface of the face is H1 and a distance parallel to the front surface of the face from the center of the face to a width center position of the sole-side rib is H2, a ratio H2 / H1 is 0.20 to 0.

41.

7. A golf club head as described in any one of claims 1 to 6, wherein the sole-side thin portion is formed within a face line forming range in which the face line is formed in the toe-heel direction.

8. 8. The golf club head according to claim 1, wherein the sole-side thin portion includes a bottom surface, a side surface, and an arcuate surface smoothly connecting these surfaces, and the arcuate surface has a radius of curvature of 1.0 to 2.0 mm.

9. 9. The golf club head according to claim 1, wherein the thickness of the central thin portion is 1.5 to 2.5 mm, the thickness of the sole side thin portion is 0.9 to 1.5 mm, and the thickness of the sole side rib is 2.0 to 3.0 mm.

10. 10. The golf club head according to claim 1, which is an iron type.

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