Golf club head

Abstract

To provide a golf club head that is improved in repulsion performance in a principal hitting position by reducing a sweet spot without impairing durability.SOLUTION: A golf club head 1 includes a face part 2. The face part 2 includes: a face 21 that is a surface for hitting a ball; and a face rear face 22 that is a surface on an opposite side thereto. The face part 2 includes a first thin wall region 24 formed by recessing the face rear face 22. The first thin wall region 24 is formed in a toe upper region A1 that is a region on an upper side from a sweet spot SS and on a toe side in a face front view when being viewed from a direction orthogonal to the face 21. The first thin wall region 24 is formed on an outside from a region A2 that is a 5 mm radius about the sweet spot SS. The first thin wall region 24 has an area having a certain ratio to an area of the toe upper region. The first thin wall region 24 is a single region having a closed outline. The outline is provided without hanging out of the toe upper region A1.SELECTED DRAWING: Figure 8

Description

Technical Field

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

Background Art

[0002] The following Patent Document 1 proposes an iron-type golf club head that can provide a good hitting feeling.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Golf club heads such as iron-type, fairway wood, or hybrid have many opportunities to hit a golf ball placed directly on the grass. For this reason, this type of golf club head tends to frequently hit the ball at a position about 15 mm upward from the lowermost end of the face.

[0005] On the other hand, in the face, the position where the repulsion is highest is near the sweet spot. However, in the case of the above-described golf club head, usually, the sweet spot is located at a position about 20 to 22 mm upward from the lowermost end of the face. For this reason, in this type of golf club head, the main hitting position and the position with high repulsion do not coincide, and thus there is room for further improvement in improving the flying distance of the hit ball.

[0006] The present invention has been devised in view of the above problems, and the main object is to provide a golf club head that can lower the sweet spot without impairing durability and improve the repulsion performance at the main hitting position.

Means for Solving the Problems

[0007] The present invention relates to a golf club head having a face portion, wherein the face portion has a face which is a surface for hitting a ball and a face back surface which is the opposite surface thereof, and a first thin-walled region is formed in the face portion by recessing the face back surface. In a front view of the face seen from a direction orthogonal to the face, the first thin-walled region is formed in an upper toe region which is a region above and on the toe side of the sweet spot, the first thin-walled region is formed outside a region having a radius of 5 mm centered on the sweet spot, and the area of the first thin-walled region is 15% to 70% of the area of the upper toe region.

[0008] In another aspect of the present invention, the thickness of the first thin-walled region may be in the range of 0.5 to 2.0 mm.

[0009] In another aspect of the present invention, the first thin-walled region may be formed outside a region having a radius of 10 mm centered on the sweet spot.

[0010] In another aspect of the present invention, the first thin-walled region may have the smallest thickness among the face portions.

[0011] In another aspect of the present invention, the face portion includes a face plate and a face receiving portion having a support surface that supports a peripheral portion of the face plate from behind the head. In the front view of the face, a part of the first thin-walled region overlaps the support surface, and the first thin-walled region may be separated from the support surface in the head front-rear direction.

[0012] In another aspect of the present invention, grooves extending in the toe-heel direction may be formed above and / or below the face back surface.

[0013] In another aspect of the present invention, the thickness of the portion of the face portion where the groove is provided may be larger than the thickness of the first thin-walled region.

[0014] In another aspect of the present invention, the groove may be spaced apart from the first thin-walled region.

[0015] In another aspect of the present invention, the toe side of the groove may communicate with the first thin-walled region.

[0016] In another aspect of the present invention, the face portion includes a face plate and a face receiving portion having a support surface that supports the peripheral edge of the face plate from behind the head. In the front view of the face, at least a part of the groove overlaps the support surface, and the groove may be spaced apart from the support surface in the head front-rear direction.

[0017] In another aspect of the present invention, the golf club head may be an iron-type golf club head.

Advantages of the Invention

[0018] By adopting the above configuration, the golf club head of the present invention can lower the sweet spot without impairing durability and improve the repulsion performance at the main hitting position.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Mode for Carrying Out the Invention

[0020] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Several embodiments disclosed below are not intended to be limited in any way. Furthermore, the disclosed embodiments can be used alone or in various combinations. Furthermore, throughout this specification, the same or common elements are given the same reference numerals, and duplicate explanations are omitted.

[0021] FIGS. 1 to 4 are, respectively, a front view, a rear view, a cross-sectional view taken along the line III-III of FIG. 1, and an exploded perspective view of a golf club head (hereinafter, sometimes simply referred to as "head") 1 of the present embodiment. The present invention can be preferably implemented in a head that has many opportunities to strike a golf ball placed directly on the grass. In the present embodiment, an iron-type golf club head is exemplified as such a head. In other forms, the head 1 may be configured as, for example, a fairway wood or a utility.

[0022] The head 1 includes, for example, a face part 2, a top 3, a sole 4, a toe 5, a heel 6, and a hosel 7.

[0023] The face portion 2 has a face 21 which is a surface for hitting a ball, and a face back surface 22 which is the surface on the opposite side thereof. On the face 21, a plurality of face lines 8 (see FIG. 5) are formed for the purpose of increasing the friction with the ball. The face lines 8 are grooves extending in the toe-heel direction. In the drawings other than FIG. 5, the face lines 8 are omitted.

[0024] [Reference state] In FIGS. 1 to 4, the head 1 is in a reference state. In this specification, the "reference state" of the head 1 means that, as conceptually shown in FIG. 5, the face lines 8 formed on the face 21 of the head 1 are parallel to the horizontal plane HP, and the head 1 is placed on the horizontal plane HP. In the reference state, the central axis CL (the axis of the club shaft) of the hosel 7 of the head 1 is arranged within the reference vertical plane VP. The reference vertical plane VP is a plane perpendicular to the horizontal plane HP. In this reference state, the face lines 8 are parallel to both the horizontal plane H and the reference vertical plane VP. Also, in FIG. 5, α represents the lie angle and β represents the loft angle, respectively. In this specification and the claims, unless otherwise specifically mentioned, the head 1 is assumed to be in the reference state, and the configuration of each part is described.

[0025] [Each direction of the head] Referring to FIG. 5, the front side of the head 1 means the side of the face 21 in the reference state. The rear side or the back side of the head 1 means the side opposite to the face 21. Also, the head front-rear direction is the direction of the x-axis orthogonal to the reference vertical plane VP in FIG. 5. Also, the toe-heel direction of the head 1 is the direction of the horizontal y-axis orthogonal to the head front-rear direction. The up-down direction of the head 1 is the direction of the z-axis orthogonal to both the x-axis and the y-axis, and the "upper side" and "lower side" of the head 1 correspond to the "upper side" and "lower side" in the reference state, respectively.

[0026] [Structure of each part of the head] As shown in FIGS. 1 and 3, face 21 includes a sweet spot SS. The sweet spot SS is the intersection of the normal line N drawn from the head center of gravity CG to the face 21 and the face 21, as shown in FIG. 3. The sweet spot SS is one of the hitting points with excellent repulsion.

[0027] In the case of the iron-type head 1 of the present embodiment, the face 21 is formed of a flat surface. Therefore, in the case of an iron-type head, the face portion 2 is a portion having such a flat face 21 as the front face.

[0028] On the other hand, when the head 1 is a fairway wood or a hybrid, the face 21 can be formed of a curved surface having, for example, a roll and / or a bulge. In this case, the face portion 2 is a portion surrounded by the periphery of the face 21. In this specification, the periphery of the face 21 is defined as follows. First, as shown in FIG. 6(A), each cross section s1, s2, s3... including the normal line N connecting the head center of gravity CG and the sweet spot SS is specified. Then, as shown in FIG. 6(B), in each of the cross sections s1, s2, s3..., a position Pe where the radius of curvature r of the contour line Lf on the outer side of the head becomes 200 mm for the first time from the sweet spot SS side toward the outside of the face is obtained, and the connection of these positions Pe is defined as the periphery E of the face 21.

[0029] As shown in FIG. 3, the top 3 extends from the upper edge of the face 21 to the rear of the head 1 so as to constitute, for example, the upper surface portion of the head 1. The top 3 may be called a crown or "upper part of the head".

[0030] The sole 4 extends from the lower edge of the face 21 to the rear of the head 1 so as to form the lower surface portion of the head 1. The sole 4 may be referred to as the "lower part of the head". In the present embodiment, a back wall portion 10 is further provided behind the sole 4. The back wall portion 10 extends from a position separated rearward from the back surface 22 of the face toward the upper head side. Thereby, a pocket-shaped cavity i is formed behind the face portion 2 of the head 1 in the present embodiment. The back wall portion 10 helps to form the head center of gravity CG lower and deeper.

[0031] The toe 5 is the end portion farthest from the hosel 7 in the toe-heel direction of the head 1, and smoothly connects between the top 3 and the sole 4. The heel 6 is the end portion located on the opposite side of the toe 5 in the toe-heel direction of the head 1, and the hosel 7 is connected thereto.

[0032] The hosel 7 is configured, for example, in a cylindrical shape, and has a shaft insertion hole 7a for receiving a club shaft (not shown) as shown in FIG. 1. The central axis CL of the hosel 7 is defined by the central axis of the shaft insertion hole 7a.

[0033] As shown in FIG. 4, the head 1 of the present embodiment is configured by joining, for example, a face plate 100 and a head body 200.

[0034] In the present embodiment, the face plate 100 and the head body 200 are made of different metal materials. For the face plate 100, for example, a metal material having high strength is suitable, and for example, titanium, titanium alloy, stainless steel, maraging steel, etc. can be adopted. For the head body 200, for example, stainless steel, carbon steel for mechanical structures, etc. are suitable.

[0035] The face plate 100 of the present embodiment has a plate shape and has a front surface 101, a back surface 102, and side surfaces 103.

[0036] In this embodiment, the front surface 101 of the face plate 100 can constitute the main part of the face 21.

[0037] In this embodiment, the back surface 102 of the face plate 100 constitutes the main part of the face back surface 22.

[0038] In this embodiment, the side surface 103 of the face plate 100 has, for example, a side surface 103a on the toe 3 side, a side surface 103b on the sole 4 side, a side surface 103c on the toe 5 side, and a side surface 103d on the heel 6 side.

[0039] In a preferred aspect, among the side surfaces 103 of the face plate 100, at least one, preferably a plurality, and more preferably all of the side surface 103a on the toe 3 side, the side surface 103b on the sole 4 side, and the side surface 103c on the toe 5 side are formed so as to be exposed on the outer surface of the head. In this embodiment, as shown in FIGS. 1 and 3, the side surface 103a on the toe 3 side, the side surface 103b on the sole 4 side, and the side surface 103c on the toe 5 side of the face plate 100 are exposed on the outer surface of the head so as to constitute the front side portions of the toe 3, the sole 4, and the toe 5 of the head, respectively. Such a face plate 100 forms a wider range of the face 21 and helps to provide high repulsion performance.

[0040] As shown in FIG. 4, the head body 200 includes, for example, a heel 6, a hosel 7, a back wall portion 10, and a face receiving portion 201.

[0041] The face receiving portion 201 is formed in an annular shape so as to define, for example, an opening O penetrating in the head front-rear direction, and includes a top side receiving portion 201a, a sole side receiving portion 201b, a toe side receiving portion 201c, and a heel side receiving portion 201d. The top side receiving portion 201a, the sole side receiving portion 201b, and the toe side receiving portion 201c form the rear portions of the top 3, the sole 4, and the toe 5 of the head 1, respectively. These receiving portions distribute a large weight to the peripheral side of the face portion 2 and help to increase the moment of inertia of the head 1.

[0042] The face receiving portion 201 also has a support surface 202 that supports the peripheral edge portion 100e of the face plate 100 from behind the head. The support surface 202 of the present embodiment is formed in an annular shape so as to connect the top side receiving portion 201a, the sole side receiving portion 201b, the toe side receiving portion 201c, and the heel side receiving portion 201d. Note that the face plate 100 and the head body 200 are fixed by various joining methods such as welding, brazing, caulking, etc., so that the support surface 202 and the face back surface 22 are in contact with each other.

[0043] As described above, the face portion 2 of the head 1 of the present embodiment is configured as a composite of the face plate 100 and the face receiving portion 201. However, the head 1 of the present invention is not limited to such a mode. As another mode, the head 1 of the present invention may have a one-piece structure integrally formed by casting, forging, or the like.

[0044] FIG. 7 is a cross-sectional view taken along line VII-VII of FIG. 1. As shown in FIGS. 1 and 7, a first thin-walled region 24 is formed in the face portion 2 by recessing the face back surface 22. The first thin-walled region 24 of the present embodiment is formed by recessing the back surface 102 of the face plate 100.

[0045] The first thin-walled region 24 includes, for example, a portion having a wall thickness t1. This wall thickness t1 is relatively small among the face portion 2. The wall thickness t1 of the first thin-walled region 24 of the present embodiment is formed to be the smallest in the wall thickness distribution of the face portion 2.

[0046] [First Embodiment] FIG. 8 is a front view of the face as viewed from a direction orthogonal to the face 21. As shown in FIG. 8, the first thin-walled region 24 of the first embodiment is formed in the upper toe region A1, which is a region above and on the toe side of the sweet spot SS. The upper toe region A1 is a region above the horizontal line L1 passing through the sweet spot SS and on the toe 5 side of the vertical line L2 passing through the sweet spot SS and orthogonal to the horizontal line L1 in the front view of the face.

[0047] The first thin-walled region 24 of this embodiment is a single region having a closed contour, and a case is shown where this contour is provided without protruding from the upper region A1 of the club head. In other forms, the first thin-walled region 24 may protrude from the upper region A1 of the club head.

[0048] Also, in the face front view, the first thin-walled region 24 is formed outside a region A2 with a radius of 5 mm centered on the sweet spot SS. In other words, the first thin-walled region 24 does not enter the region A2. Therefore, the region A2 is formed with a wall thickness greater than the wall thickness t1 of the first thin-walled region 24.

[0049] Furthermore, in the face front view, the area of the first thin-walled region 24 is set to be 15% to 70% of the area of the upper region A1 of the club head. Here, the area of the upper region A1 of the club head is the area of the region surrounded by the straight lines L1, L2, and the head contour in the face front view.

[0050] [Operation of this Embodiment] Since the first thin-walled region 24 is formed in the upper region A1 of the club head of this embodiment, the weight above the sweet spot SS is reduced, and thus a lower sweet spot SS can be provided. Therefore, the club head 1 of this embodiment has improved repulsion performance when hitting the ball at a relatively low position on the face 21. That is, the repulsion performance at the main hitting positions of club heads such as iron type, fairway wood, and hybrid is improved, and the flying distance of the hit ball is increased. In a preferred aspect, by adjusting the area and / or wall thickness of the first thin-walled region 24, the sweet spot SS can be located in the range of 19 to 21 mm from the horizontal plane HP.

[0051] In addition, the inventors examined the stress distribution on the face during ball striking for an iron-type head. The ball striking position was set at 15 mm above the lowermost end of the face and at the center in the toe-heel direction of the face. The results are shown in FIG. 9, where the stress is represented by the shade of color. Also, FIG. 9 is a diagram of the face portion viewed from the back side. As is clear from FIG. 9, the largest stress occurs at the striking position S1, but in the above-mentioned upper toe region A1, only a very small stress occurs and it hardly bends.

[0052] In the head 1 of the present embodiment, by forming the first thin-wall region 24 in the upper toe region A1, the upper toe region A1 is configured to be easily bent. Therefore, the head 1 of the present embodiment can expand the bending region of the face 21 and further improve the repulsion by promoting the bending of the upper toe region A1, which has hardly bent until now, during ball striking. Also, by providing the first thin-wall region 24, the face 21 becomes more easily deflected even when the ball is struck above the sweet spot SS, so the repulsion performance of the upper hitting point is also enhanced, and as a result, the high-repulsion area can also be expanded.

[0053] Regarding the vicinity of the sweet spot SS, since there is a possibility of actual hitting, the first thin-wall region 24 is formed outside the region A2 with a radius of 5 mm centered on the sweet spot SS. Thereby, the above-mentioned action can be exhibited without deteriorating the durability of the face portion 2. In order to more surely suppress the deterioration of the durability of the face portion 2, the first thin-wall region 24 is preferably outside the region A3 with a radius of 10 mm centered on the sweet spot SS, and more preferably outside the region A4 with a radius of 15 mm.

[0054] In addition, since the area of the first thin-wall region 24 is set to be 15% to 70% of the area of the upper part region A1 of the club head, the upper part region A1 of the club head achieves both durability and a large deflection during ball impact. That is, when the area of the first thin-wall region 24 is less than 15% of the area of the upper part region A1, the deflection of the upper part region A1 of the club head during ball impact cannot be obtained sufficiently, and as a result, it tends to be difficult to obtain a low sweet spot SS and an increased effect of a high-rebound area. Conversely, when the area of the first thin-wall region 24 exceeds 70% of the area of the upper part region A1, the durability of the face portion 2 may deteriorate. In order to achieve these various performances in a higher dimension, the area of the first thin-wall region 24 is preferably 20% or more, more preferably 25% or more of the area of the upper part region A1, while it may be preferably 60% or less, more preferably 50% or less.

[0055] [Thickness of the face portion] In the present embodiment, although the wall thickness t1 of the first thin-wall region 24 is not particularly limited, in order not to impair the durability, it is, for example, 0.5 mm or more, preferably 1.0 mm or more, and more preferably 1.2 mm or more. Also, the wall thickness t1 of the first thin-wall region 24 is, for example, 2.0 mm or less, preferably 1.8 mm or less, and more preferably 1.6 mm or less in order to further enhance the effect of making the upper part region A1 of the club head more easily deflect while lowering the sweet spot SS.

[0056] The reference wall thickness t2 of the face portion 2 (in the present embodiment, it is the maximum wall thickness t2 of the face plate 100, and the same applies hereinafter) is not particularly limited, but in order to more surely suppress the deterioration of the durability, it is preferably larger than the wall thickness t1, and may be, for example, 1.0 mm or more, preferably 1.5 mm or more, and more preferably 1.8 mm or more. Also, the wall thickness t2 of the face portion 2 may be, for example, 3.0 mm or less, preferably 2.5 mm or less, and more preferably 2.2 mm or less in order to make it more easily deflect.

[0057] [Aspect of the first thin-wall region] As shown in FIG. 8, the first thin-wall region 24 may be provided to extend widely on the outer peripheral side of the face 21 in order to make the upper region A1 of the club head more effectively bendable. For example, in the front view of the face shown in FIG. 8, a part of the first thin-wall region 24 may be formed so as to overlap the support surface 202 of the head body 200.

[0058] On the other hand, FIG. 10 is a cross-sectional view taken along the line X-X of FIG. 8. As shown in FIG. 10, the first thin-wall region 24 overlapping the support surface 202 is preferably separated from the support surface 202 in the head front-rear direction. In such a mode, the first thin-wall region 24 that is easily bendable during ball striking can be extended to the outer peripheral side of the face 21 without being restricted by the support surface 202, and thus it is preferable in that the face 21 can be configured to be more easily bendable.

[0059] [Second Embodiment] FIG. 11 shows a front view of the face of the second embodiment. As shown in FIG. 11, in the head 1 of this embodiment, grooves 26 extending in the toe-heel direction are further formed above and / or below the back surface 102 (shown in FIG. 4) of the face plate 100 as the face back surface 22.

[0060] In this embodiment, the groove 26 includes a top-side groove 26a and a sole-side groove 26b, but only either one of them may be provided.

[0061] The top-side groove 26a extends in the toe-heel direction above the sweet spot SS. The sole-side groove 26b extends in the toe-heel direction below the sweet spot SS. Both grooves 26a and 26b extend across the vertical line L2 along the contour of the face 21. Further, the toe sides of the top-side groove 26a and the sole-side groove 26b have closed ends and are configured to be separated from the first thin-wall region 24.

[0062] FIG. 12 is a cross-sectional view taken along line XII-XII of FIG. 10. As shown in FIG. 12, the portion of the face portion 2 where the groove 26 is provided is thinned and has a wall thickness t3. This wall thickness t3 is smaller than the reference wall thickness t2 of the face portion 2. Therefore, in the head 1 of this embodiment, when hitting a ball, the upper and / or lower portions of the face 21 are more likely to bend, so that the high-rebound area is further enlarged.

[0063] In a preferred embodiment, as shown in FIG. 11, the groove 26 may be provided so as to be located more on the outer peripheral side of the face 21 in order to bend the face portion 2 more. For example, in the front view of the face in FIG. 11, a part of the groove 26 (the groove 26b on the sole side in this embodiment) may be formed so as to overlap the support surface 202 of the head body 200.

[0064] On the other hand, as shown in FIG. 12, the groove 26 (the groove 26b on the sole side in this example) that overlaps the support surface 202 is preferably separated from the support surface 202 in the head front-rear direction. In such an embodiment, the portion of the groove 26 that is likely to bend during ball hitting can be positioned on the outer peripheral side of the face 21 without being restricted by the support surface 202, and thus, it is preferable in that the face 21 can be configured to be more likely to bend.

[0065] The wall thickness t3 of the portion where the groove 26 is provided is not particularly limited, but from the viewpoint of ensuring the durability of the face portion 2, for example, it is preferably in the range of 1.50 to 2.0 mm. In particular, the wall thickness t3 of the groove 26 is preferably larger than the wall thickness t1 of the first thinned region 24. That is, the wall thickness of the face portion 2 is preferably set as t1 < t3 < t2.

[0066] The width w (shown in FIG. 12) of the groove 26 is, for example, 0.5 mm or more, preferably 1.0 mm or more, and more preferably 1.5 mm or more. However, from the viewpoint of maintaining the durability of the face portion 2, for example, it is 3.0 mm or less, preferably 2.5 mm or less, and more preferably 2.0 mm or less.

[0067] In the second embodiment, when there is a groove 26 away from the first thin region 24 and a part of this groove 26 extends within the upper toe region A1, the "area of the first thin region 24" is defined as the total area of the first thin region 24 and the groove 26 within the upper toe region A1.

[0068] [Third Embodiment] FIG. 13 shows a front face view of the third embodiment. As shown in FIG. 13, in the head 1 of the third embodiment as well, grooves 26 extending in the toe - heel direction are formed above and / or below the back surface 102 (shown in FIG. 4) of the face plate 100 as the face back surface 22. However, in the third embodiment, the toe sides of the top - side groove 26a and the sole - side groove 26b are different from the second embodiment in that they communicate with the first thin region 24. Such an aspect is preferable in that the first thin region 24 and the groove 26 can cooperate to make the face 21 more easily bendable.

[0069] In the third embodiment, when there is a groove 26 communicating with the first thin region 24 and a part of this groove 26 extends within the upper toe region A1, the "area of the first thin region 24" is defined as the total area of the first thin region 24 and the groove 26 within the upper toe region A1.

[0070] As described above in detail for the embodiments of the present invention, the present invention is not limited to the above - described specific disclosure, and various modifications can be made and implemented within the scope of the technical idea described in the claims. [Examples]

[0071] To confirm the effects of the present invention, more detailed examples of the present invention will be described. However, the present invention is not to be construed as being limited to these examples.

[0072] An iron-type golf club head (Example) having the basic structure shown in FIGS. 1 to 4 was prototyped based on the specifications in Table 1, and their performance was tested (Example). Also, for comparison, a golf club head outside the present invention (Comparative Example) was similarly tested. Comparative Example 1 has a face plate with a constant thickness (thickness t2). The main common specifications are as follows. Gauge: I#6 Head weight: 260 g Thickness t1 of the first thin-walled region: 1.55 mm Reference thickness t2 of the face plate: 2.10 mm For the head having a groove, the thickness t3 of that part: 1.65 mm Width w of the groove: 2 mm

[0073] As the bounce performance, the COR was calculated by computer simulation. COR means the coefficient of restitution and was calculated based on the "Interim Procedure for Measuring the Coefficient of Restitution of an Iron Clubhead Relative to a Baseline Plate Revision 1.3 January 1, 2006" defined by the USGA (United States Golf Association). The larger the COR value, the better the bounce of the face at the measurement position can be evaluated. The COR values were calculated at two locations: the position of the sweet spot (SS position) and the position 15 mm above from the lowermost end of the face and at the intermediate position in the toe-heel direction (lower hitting position).

[0074] In addition, as for durability, actual hitting tests were conducted. In this test, an iron-type golf club (total length: 38 inches) was prototyped by attaching the same FRP club shaft to each golf club head, and these were attached to a swing robot. The golf balls were hit with each club after adjusting so that the head speed became 39 m / s, and the number of hits until damage occurred to the face part was measured (maximum 10,000 hits). The measurement was performed visually every 100 ball hits. The results indicate that the greater the numerical value, the better the durability. In the case where no damage occurred, it is indicated as "no damage". The results of the test are shown in Table 1.

[0075]

Table 1

[0076] As a result of the test, it was confirmed that the head of the example has a lower sweet spot position and an improved COR at the downswing position without sacrificing durability.

Explanation of Signs

[0077] 1 Golf club head 2 Face part 5 Toe 6 Heel 21 Face 22 Back surface of face 24 First thin-wall region 26 Groove 100 Face plate 100e Peripheral part of face plate 102 Back surface of face plate 200 Head body 201 Face receiving part 202 Support surface A1 Upper region of toe SS Sweet spot

Claims

1. A golf club head having a face portion, The face portion has a face which is a surface for striking a ball, and a face back surface which is an opposite surface thereof, A first thin-walled region is formed in the face portion by recessing the back surface of the face, In a face front view seen from a direction perpendicular to the face, The first thin region is formed in a toe upper region that is a region above the sweet spot and on the toe side, The first thin-walled region is formed outside a region having a radius of 5 mm centered on the sweet spot, The area of ​​the first thin region is 15% to 70% of the area of ​​the toe upper region; the first thin region is a region having a closed contour; The contour is provided without extending beyond the toe upper region. Golf club head.

2. 2. The golf club head according to claim 1, wherein the thickness of the first thin region is in the range of 0.5 to 2.0 mm.

3. 3. The golf club head according to claim 1, wherein the first thin region is formed outside a region having a radius of 10 mm centered on the sweet spot.

4. 4. The golf club head according to claim 1, wherein the first thin region has the smallest thickness in the face portion.

5. The face portion includes a face plate and a face receiving portion having a support surface that supports a peripheral portion of the face plate from a rear of the head, In a front view of the face, a portion of the first thin-walled region overlaps the support surface, 5. The golf club head according to claim 1, wherein the first thin region is spaced apart from the support surface in the front-rear direction of the head.

6. 6. The golf club head according to claim 1, wherein a groove extending in a toe-heel direction is formed on the upper side and / or the lower side of the back surface of the face.

7. 7. The golf club head according to claim 6, wherein a thickness of the portion of the face where the groove is provided is greater than a thickness of the first thin region.

8. 8. The golf club head according to claim 6, wherein the groove is spaced apart from the first thin region.

9. The face portion includes a face plate and a face receiving portion having a support surface that supports a peripheral portion of the face plate from a rear of the head, In a front view of the face, at least a portion of the groove overlaps the support surface; 9. The golf club head according to claim 6, wherein the groove is spaced apart from the support surface in the front-rear direction of the head.

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

Images