Golf club head and golf club

Abstract

To provide a golf club head capable of obtaining high repulsion in a face part, suppressing weight increase of the head, and lowering the center of gravity, in a well-balanced manner.SOLUTION: A golf club head 10 according to the present invention has a head body 10A in which a top part 20, a sole part 30, a toe part 40, a heel part 50, a shaft part 60, and a face part 70 are integrally formed of an iron material, wherein the sole part 30 has a sole region at a lower end of the face part 70 with a sole width of 4 mm or more, is welded with a high-density material 32 extending in a toe-heel direction and having a specific gravity of 16 or more at a rear end of the sole region, and wherein the height H of the head body is 52 mm or more, the height of the center of gravity is 17.0 mm or less, and the ratio of the low center of gravity is 32% or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a golf club, and more particularly to a golf club head suitable for an iron-type golf club. [Background technology]

[0002] Conventionally, it is known that the head of an iron-type golf club has a face member (face plate) that is separate from the head body, where the ball is hit, and that this is fixed around an opening formed in the head body by adhesive, welding, caulking, etc. In order to reduce the weight of such heads, it is known that the face member is made of lightweight metal such as titanium, titanium alloy, aluminum alloy, etc., as disclosed in Patent Documents 1 to 3, for example. These documents also disclose that a weight adjustment member is attached to the sole portion of the head body in order to lower the center of gravity of the head. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2020-81642 [Patent Document 2] Patent Publication No. 2005-125090 [Patent Document 3] Utility Model Registration No. 3152899 Summary of the Invention [Problem to be solved by the invention]

[0004] However, face plates made of the above-mentioned lightweight metal materials do not provide sufficient repulsion performance, limiting the improvement of flight distance. In particular, a structure is required around the periphery of the face plate to secure the face plate to the head body, which impedes repulsion and reduces flight distance performance.

[0005] The present invention has been made in response to the above-mentioned problems, and aims to provide a golf club head and a golf club that achieve a good balance between high resilience in the face, suppression of head weight, and a low center of gravity. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the present invention provides an iron-type golf club head having a head body in which a top portion, a sole portion, a toe portion, a heel portion, a hosel portion, and a face portion are integrally formed from an iron-based material, wherein the sole portion has a sole region at the lower end of the face portion with a sole width of 4 mm or more, and a high-specific-gravity material having a specific gravity of 16 or more that extends in the toe-heel direction and is welded to the rear end of the sole region, and the height of the head body is 52 mm or more, the height of the center of gravity is 17.0 mm or less, and the low center of gravity ratio is 32% or less.

[0007] The head body having the above-described configuration has a top portion, sole portion, toe portion, heel portion, hosel portion, and face portion integrally formed from a high-strength iron-based material. This allows for a thinner wall thickness compared to titanium alloys or aluminum alloys, and the use of this material in the face portion improves repulsion. Furthermore, rather than forming the face portion as a plate and fastening it to the head body, the face portion is integrated with the top portion, sole portion, toe portion, and heel portion into an L-shaped cross section. This eliminates the need for a structure for fastening the plate, thereby efficiently improving repulsion. In this case, while the head body is lighter due to the thinner face portion, the sole portion has a sole region at the lower end of the face portion with a sole width of 4 mm or more, and a high-specific-gravity material with a specific gravity of 16 or more is welded to the rear end of this sole region, extending in the toe-to-heel direction. This makes it possible to set the head body height to 52mm or more, the center of gravity height to 17.0mm or less, and the low center of gravity ratio to 32% or less, thereby achieving high repulsion while achieving a balanced low center of gravity and improving distance performance. [Effects of the Invention]

[0008] According to the present invention, a golf club head and a golf club are obtained that can obtain high repulsion in the face portion, and can suppress an increase in the weight of the head while achieving a low center of gravity in a well-balanced manner. [Brief explanation of the drawings]

[0009] [Figure 1] 1A and 1B are diagrams showing an embodiment of a golf club head according to the present invention, in which (a) is a front view of the head, (b) is a view of the head from the toe side, and (c) is a view of the head from the sole side. [Figure 2] FIG. 2 is a rear view of the head shown in FIG. 1. [Figure 3] FIG. 2 is a perspective view of the head shown in FIG. 1 as seen from the back side above. [Figure 4] 2 is a perspective view of the head shown in FIG. 1 as seen from the lower back side. [Figure 5] FIG. 2 is a bottom view of the head shown in FIG. 1. [Figure 6] FIG. 2 is an exploded perspective view of the components of the head shown in FIG. 1. [Figure 7] 10A and 10B are diagrams showing the face portion with the high-density material and nameplate removed, in which FIG. 10A is a perspective view seen from the upper back side, and FIG. 10B is a perspective view seen from the lower back side. [Figure 8] (a) is a diagram showing the head shown in Figure 2 with the nameplate removed, (b) is a cross-sectional view taken along line AA in Figure (a), and (c) is a cross-sectional view taken along line BB, which corresponds to the center of the scoreline in Figure (a). [Figure 9] FIG. 8(b) is a cross-sectional view taken along line BB in FIG. 8(a), illustrating the dimensional relationship. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of a golf club head (hereinafter also referred to as a head) according to the present invention will be described with reference to FIGS.

[0011] The golf club 1 to which the head 10 according to this embodiment is attached is an iron type, and is configured such that the tip of the shaft 5 is fitted into and fixed to a hosel portion 60 integrally formed with the head body 10A. The head 10 is set so that, when the golf club 1 is held with respect to a reference horizontal plane P, a predetermined loft angle α is formed between a vertical plane P1 including an axis X of the fixed shaft 5 and a face surface 70a of a face portion 70 of the head body 10A according to the club number (see FIG. 9). The shaft 5 may be made of steel or fiber reinforced plastic (FRP).

[0012] The head body 10A includes a top portion 20, a sole portion 30, a toe portion 40, a heel portion 50, a hosel portion 60, and a face portion 70, which are integrally formed from an iron-based material. The iron-based material is an iron-based material other than pure iron, such as a high-strength SUS (stainless steel alloy) or chromium-ribdenum steel, which has a high specific gravity (specifically, a specific gravity of 7.6 to 7.9). The present invention is characterized in that it does not use a conventional material with a low specific gravity, such as a titanium alloy or an aluminum alloy.

[0013] Although the above-mentioned iron-based materials have a higher specific gravity than titanium alloys or aluminum alloys, they have high strength, and their high strength allows them to be thinned to achieve weight reduction. In particular, when the face portion 70 is formed from an iron-based material, its high strength allows it to be thinned, which makes it possible to achieve a good balance between weight reduction and improved resilience through this thinning. Furthermore, the face portion 70 of the present invention is not formed as a plate and attached to the head body, but is instead integrated with the top portion 20, sole portion 30, toe portion 40, and heel portion 50 (having an L-shaped cross section) as shown in FIGS. 8(c) and 9. This eliminates the need for a structure for attaching plates as in the past, making it possible to efficiently improve resilience and reduce weight.

[0014] The integrated head body 10A as described above can be formed by casting, forging, etc. Furthermore, by integrating each part of the head body with an iron-based material in this way, it is possible to form a cavity structure (pocket cavity structure), which not only improves the flight distance but also stabilizes the directionality.

[0015] The top portion 20, sole portion 30, toe portion 40, and heel portion 50 of the head body 10A extend rearward along the periphery of the face portion . In this embodiment, the top portion 20 includes an extension portion 20a extending toward the back side and a bent portion 20b whose tip end is bent downward. The sole portion 30 includes a sole extension portion (also simply referred to as an extension portion) 30a extending toward the back side and a rising portion 30b whose tip end on the back side is bent upward. Similarly, the toe portion 40 and heel portion 50 also include extension portions 40a, 50a extending toward the back side and a bent portion 40b whose tip end is bent inward. Note that the heel side does not necessarily have to be formed because it has sufficient rigidity (see FIG. 8(b)).

[0016] According to the above-described configuration, extensions 20a, 30a, 40a, and 50a are formed around the periphery of the face portion 70, extending toward the back side, and the tip ends of these extensions are bent toward the center, so that the head main body 10A has a cavity structure that is open to the rear side of the face portion 70. This improves the flexibility of the entire face portion, and increases the moment of inertia, making it possible to improve the flight distance and stabilize the directionality.

[0017] The above-described cavity structure is configured by forming extensions 20a, 40a, 50a in the top portion 20, toe portion 40, and heel portion 50, respectively, and also forming a sole extension (sole region) 30a in the sole portion 30, with bent portions 20b, 40b formed in the extensions 20a, 40a. In this case, the bent portions 20b, 40b and the rising portion 30b of the sole portion, which are configured from an iron-based material, are preferably formed within the following ranges to ensure rigidity that can withstand the impact of a hitting ball and to avoid increasing the weight of the head.

[0018] Here, a preferred range of the width of the frame (wall thickness of the bent portion and the rising portion) for forming the cavity structure will be described with reference to Figures 8 and 9. Note that although the chamfered portion is excluded here, it may be included. The width W1 of the bent portion 20b of the top portion 20 when viewed from the back side (frame width at the outer periphery) is preferably set to 2.5 mm to 3.5 mm, and the length L1 of the extension portion 20a is preferably set to 5.5 mm to 8.0 mm. The width W2 in the left-right direction of the bent portion 40b when the toe portion 40 is viewed from the back side (frame width as the outer periphery) is preferably set to 2.5 mm to 5.0 mm. Furthermore, the vertical width W3 of the sole portion 30 (frame width which is the outer periphery) may be 2.0 mm or more, and if a raised portion 30b as described below is formed, it is preferable that the vertical width (frame width) W3 be set to 2.0 mm to 5.0 mm.

[0019] As shown in Fig. 1, the head main body 10A has a shape in which the height of the face portion 70 increases from the heel side to the toe side, and a face surface 70a of the face portion 70, which has a similar shape, has a plurality of scorelines 71 formed in parallel along the toe-heel direction. As shown in Fig. 1, when the head main body 10A is viewed from the front, the area in which the scorelines 71 are formed is the actual ball-striking surface 70a' of the face portion 70. It is preferable that this ball-striking surface 70a' be subjected to various types of surface roughening treatment.

[0020] Because the face portion 70 is made of a high-strength iron-based material, it can be thinned, even when aluminum alloys (specific gravity: 2.6-2.8) or titanium alloys (specific gravity: 4.4-4.5) are not strong enough. Specifically, while the lightweight metals described above require a thickness of approximately 2.4 mm to maintain strength, the iron-based material of the present invention can be thinned to 2.2 mm or less, preferably within the range of 1.5 mm to 2.0 mm, to achieve high repulsion, thereby enabling overall weight reduction. In this case, the thickness of the face portion 70 may be uniform across the entire surface, or may vary depending on the position, taking into account factors such as a low center of gravity and flexibility.

[0021] 8 and 9, the face portion 70 of this embodiment is formed with a rib 73 that is partially thickened along the toe-heel direction on the back surface of the top side in the height direction. In this case, the thickness of the face portion 70 is preferably formed so that the thickness T1 above the rib 73 (top side) is thinner than the thickness T2 below the rib 73 (sole side). Specifically, in this embodiment, the thickness T1 is set to 1.5 mm±0.5 mm, the thickness of the rib 73 is set to 2.4 mm±0.5 mm, and the thickness T2 is set to 2.0 mm±0.5 mm, and the top side is formed thinner with the rib 73 as the boundary.

[0022] As described above, by providing the rib 73 along the toe-heel direction on the back surface of the face portion 70, the rib 73 can suppress deflection, and the peak of the deflection in the vertical direction of the face portion can be shifted toward the sole side compared to a configuration without the rib. In other words, it is possible to move the peak of deflection closer to the lower position where the ball is actually hit. In addition, by making the thickness below the rib 73 thicker than the upper side (T2>T1), a lower center of gravity can be achieved, making it easier to hit the ball at the lower center of gravity position (the position of the perpendicular line drawn from the low center of gravity G to the face portion; near the sweet spot S), and improving the flexibility at that hitting position.

[0023] Furthermore, since the rear side of the face portion 70 has a cavity structure as described above, the face portion as a whole has a flexible structure, which improves the flight distance, increases the moment of inertia, and stabilizes the directionality.

[0024] A nameplate 80 bearing information such as a product number, product name, and brand name, as well as decorations, may be attached to the rear surface of the face portion 70 as needed. In this embodiment, the nameplate 80 is integrally formed from a lightweight material such as aluminum alloy or resin, or from a nickel thin film, for example. The nameplate 80 includes a plate-shaped main body 81 having substantially the same shape as the face portion 70, and a decorative portion 82 having a design such as unevenness, which is formed on the exposed surface of the main body 81. The nameplate 80 configured in this manner can be integrally attached to the rear surface of the face portion 70 by adhesive or the like.

[0025] The sole portion 30 has a rearward-extending sole region 30a (the region where the top-side surface is exposed, also referred to as a sole extension) that is bent from the lower end of the face portion 70 toward the back side. If this sole region 30a is too short, the repulsive force at the face portion decreases, so it is sufficient that a sole width L2 of 4 mm or more, preferably 6 mm or more, is ensured. However, if the sole width L2 is too long, the overall sole width becomes wide, which makes the sole appear to protrude when the player sets up the club, making it difficult to set up, or making it impossible to place a large amount of high-specific-gravity material in the region close to the ground. Therefore, the upper limit of the sole width L2 is preferably set to 25 mm or less.

[0026] In this embodiment, in order to improve the resilience of the sole region 30a, particularly in the region below the face portion, it is preferable that the thickness T3 shown in Fig. 9 is formed to be equal to or less than the thickness of the lower end of the face portion 70, and is set to 1.0 mm to 2.5 mm. In this case, it is preferable that the upper limit of the thickness T3 of the sole region 30a is set to be equal to or less than the thickness T2 of the lower end of the face portion 70, thereby reducing the weight of the sole region as well, so that the high-specific-gravity material 32 is welded to the rear end portion 30d as described below, thereby reducing the weight of the head body, lowering the center of gravity, and increasing the depth of the center of gravity.

[0027] As described above, the head structure with an L-shaped cross section made of an iron-based material can increase the repulsion of the face portion 70, but the formation of the sole region (blank region) 30a in the sole portion 30 makes it difficult to lower the center of gravity G. For this reason, a high-specific-gravity material 32 with a specific gravity of 16 or more is welded to the rear end of the sole region 30a to efficiently lower the center of gravity of the head main body. The high-specific-gravity material 32 of this embodiment has a main body 32A that extends in the toe-heel direction and has a predetermined sole width on the back side, a toe-side rising portion 32c that rises upward on both sides of the main body 32A, and a heel-side rising portion 32d.

[0028] The reason why the specific gravity of the high specific gravity material 32 is set to 16 or more is to efficiently reduce the weight of the head body and lower the center of gravity even when an iron-based material is used. Also, compared to the weights (for example, tungsten with a specific gravity of less than 10) that have conventionally been used in heads to lower the center of gravity, this is to efficiently lower the height of the center of gravity (reducing the low center of gravity ratio and lowering the center of gravity of the head body) without increasing the volume. The material of the high specific gravity material 32 is not limited, but it is possible to use a tungsten alloy with a specific gravity of 16 or more that can be welded to the rear end 30d of the sole region 30a.

[0029] In this embodiment, the high-specific-gravity material 32 is configured such that the front portion of the main body 32A is welded to the rear end 30d of the sole region 30a, forming a curved sole surface that is flush with the underside of the sole region 30a (see FIGS. 4, 5, 8(c), and 9). In this case, it is preferable to form a rising portion 30b on the rear end side of the sole region 30a that rises toward the back. By forming such a rising portion 30b, the welded area between the front portion of the main body 32A of the high-specific-gravity material 32 and the rear end 30d can be increased, thereby increasing the weld strength.

[0030] The shape of the rising portion 30b can be configured to have an inclined surface 30e that extends in the toe-heel direction and gradually rises toward the back side, as shown in Figures 8(c) and 9, but the shape is not particularly limited. For example, the welded portion between the rear end portion 30d and the main body 32A of the high-specific-gravity material 32 can be modified as appropriate, such as by forming a joining structure with concave and convex portions to increase the welded area.

[0031] In this embodiment, a step portion 32a extending in the toe-heel direction is formed on the front side of the main body 32A of the high-specific-gravity material 32, and each of the right-angled surfaces forming the step portion 32a is placed on the upper surface portion 30f of the rising portion 30b and is brought into contact with the rear end portion 30d, thereby ensuring a welding area (it is not necessary to weld up to the upper surface portion 30f).

[0032] The shape of the high-specific-gravity material 32 is not particularly limited, but it is preferable that when welded, it is approximately flush with the underside (exposed surface) of the sole region 30a and has a curved shape that gradually rises toward the back side (see Figures 8(c) and 9(c)). In this way, by welding the high-specific-gravity material 32 directly to the head body (sole region 30a) without using another member, the welding process is simplified and the weight and position of the high-specific-gravity material for lowering the center of gravity are stabilized. Also, by making the sole surface of the head flat and curved, it is possible to achieve a configuration that makes it easier to swing through.

[0033] The high specific gravity material 32 only needs to weigh 85 g or more, and is preferably placed at a position that is 13.5% or less of the head height H. The high specific gravity material 32 used in this embodiment has a specific gravity of approximately 17. In this way, by using 85g or more of high specific gravity material with a specific gravity of 17 or more and arranging it in an area of ​​13.5% or less of head height H, it becomes possible to achieve a center of gravity height of 17.0mm or less and a low center of gravity ratio of 32% or less in an iron head with a loft angle of 40° or less, which requires distance performance, making it easier to achieve a low center of gravity compared to the same configuration equipped with the above-mentioned conventional weight (tungsten with a specific gravity of less than 10). Note that it is sufficient for head height H to be 52mm or more, and it is preferable that the high specific gravity material 32 be 130g or less so that the head does not become too heavy.

[0034] As described above, the high-specific-gravity material 32 of this embodiment rises from both ends in the toe-heel direction on the sole side, and rises to the middle regions in the height direction of the toe portion 40 and the heel portion 50, respectively, and is formed so as to be flush with the surfaces of the toe portion 40 and the heel portion 50 (see FIGS. 2 to 4). The rising portion 32c on the toe portion 40 side gradually becomes thinner and is integrally fastened to a recess in the back surface of the toe portion 40. The rising portion 32d on the heel portion 50 side gradually becomes thinner and is integrally fastened to a recess in the back surface of the heel portion 50.

[0035] In this way, by forming the rising portions 32c, 32d on both sides of the high specific gravity material 32, it is possible to improve the moment of inertia of the head main body and also to increase the welding strength to the head main body.

[0036] In addition, in the head main body of this embodiment, a decorative member 85 is attached to the upper surface 32g of the high-specific-gravity material 32. By attaching such a decorative member 85, the lower side of the nameplate 80, particularly the inner surface of the sole region 30a, the welded portion between the rising portion 30b and the high-specific-gravity material 32, the inside of the cavity, and even the sense of step can be concealed, thereby enhancing the design. For this reason, the decorative member 85 can be designed in various ways, such as by coloring the surface or by making easily visible portions uneven (for example, by forming adjacent protrusions 85a, 85b). Furthermore, the decorative member 85 preferably has a lower specific gravity than the constituent material (iron-based material) of the main body member so as not to raise the center of gravity of the head 10. For example, the decorative member 85 is preferably made of a light metal (such as an aluminum alloy) or a resin (such as an ABS resin).

[0037] Next, the results of verifying the specific configuration examples of the head described above will be explained. The heads prepared for the test were made of the same iron-based material, and multiple heads were created with different loft angles (20°, 24°, 31°) for the face portion but the rest of the head having the same shape. Then, a high-specific-gravity material (tungsten alloy) 32 with a specific gravity of 17 was welded to the raised portion 30b of each head, and the results of the center of gravity height and low center of gravity ratio were tested. Furthermore, as a comparative example, a head with a substantially identical head structure but with a loft angle of 25° for the face portion was created with a normal weight (tungsten with a specific gravity of less than 10) welded thereto.

[0038] The position of the center of gravity G of each head was measured in a state in which the head main body 10A including the hosel portion 60, the high-specific-gravity material 32, the nameplate 80, and the decorative member 85 were included. In addition, for each head shown in Table 1 below, the center of gravity height H1 means the height from the ground to the center of gravity G when the golf club is in address position (see FIG. 8). The address position here means a state in which the axis X (see FIG. 9) of the hosel portion 60 is vertical when viewed from the toe side, and is placed at a lie angle set for each model (score line 71 is horizontal) when viewed from the front. The low center of gravity ratio is calculated by dividing the center of gravity height H1 by the head height H. Here, the head height H refers to the height from the reference horizontal plane P, which is the ground, to the highest point of the face portion 70 (excluding the hosel portion) in the address position shown in Fig. 1. Therefore, a lower center of gravity ratio means that a lower center of gravity has been achieved.

[0039] The measurement results are shown below. [Table 1]

[0040] The head height H was 52 mm or more for all loft angles. In this case, a head with a high specific gravity material 32 welded and a loft angle of 31° or less achieved a center of gravity height H1 of 17.0 mm or less and a low center of gravity ratio of 32% or less. However, a head with a normal weight (tungsten with a specific gravity of less than 10) welded, when set to a loft angle of 25°, would have a higher center of gravity height and a lower center of gravity ratio than the head structure of the present invention with a loft angle of 31°. In other words, with a conventional welded weight structure, it is predicted that the center of gravity height and the lower center of gravity ratio would become even higher when the loft angle is set to 25° or more, and even if a head structure such as the one of the present invention is adopted, it would be impossible to achieve high resilience and a low center of gravity design.

[0041] In this case, to facilitate a low center of gravity design such as that of the present invention, it is not preferable to dispose the high specific gravity material 32 at a high position. For the three loft angles described above (20°, 24°, and 31°), the shape and volume are secured so that the center of gravity height of the welded high specific gravity material 32 (the center of gravity height of the high specific gravity material 32 alone when in the address position) is 6.27 mm, 6.76 mm, and 5.55 mm (7.0 mm or less), respectively. Such high specific gravity material prevents the center of gravity height H1 of the head from becoming too high (when a weight body is attached to a conventional general head, the center of gravity height of the weight body is not taken into consideration, and is set to 7.5 mm or more).

[0042] Furthermore, the head body 10A to which the high specific gravity material 32 of this embodiment is welded is configured so that the sole angle β is in the range of −2° to 6°. Here, the sole angle β is defined as the angle between the tangent line La of the sole surface at the center Ca of the effective sole width Wa and the reference horizontal plane P (ground surface) in a plane defined by including the center line (SL) perpendicular to the scoreline at the center of the scoreline 71 in the toe-heel direction shown in Figure 1. In this case, the effective sole width Wa is the area that is expected to actually contact the ground at the center of the sole portion 30, and in Figures 1(b) and 1(c), it is defined as the width from the leading edge PL to the contact point Pt on the back side of the sole surface.

[0043] The sole angle β that is most advantageous for lowering the height H1 of the center of gravity is 0°. However, there is a sole angle that is suitable for each user, and it is generally a positive angle (the angle at which the leading edge PL is separated from the ground as shown in Figure 1(b)). In this case, if a low center of gravity is achieved by using high-specific-gravity material 32 welded to the back side, and the repulsion is increased to improve the flight distance, it is preferable to set the sole angle β in the range of -2° to 6°. In other words, it is not necessary to set the sole angle β to a large value (6° to 12°) like that of a wedge-type golf club head that stops the ball at close range.

[0044] However, if the sole angle β is set too large, the leading edge PL in Figure 1(b) will be separated from the ground, the head body 10A will be separated from the ground, and the center of gravity of the head will be raised, so it is preferable to set the sole angle β to 6° or less as described above. On the other hand, if the sole angle β is set too small, Pt in Figure 1(c) will be separated from the ground, the high-specific-gravity material 32 welded to the back side will be separated from the ground, and the center of gravity of the head will be raised, so it is preferable to set the sole angle β to -2° or more as described above.

[0045] Furthermore, when making an ideal swing (a state in which the ball is hit cleanly such as with a down blow or a horizontal blow), the surface of the above-mentioned high-specific-gravity material 32 is curved so as to rise toward the back side, and by setting the sole angle β to 6° or less, it is possible to prevent the high-specific-gravity material 32 from touching the ground, and even if the high-specific-gravity material 32 is welded directly to the rear end of the sole region, no direct impact from the ground is applied.

[0046] Furthermore, the width of the high specific gravity material 32 as viewed from the butt end (butt end width W4 shown in FIG. 8(c)) is preferably set to 3.0 mm to 5.0 mm. The reason for setting it in this range is that if it is thinner than 3.0 mm, it will give the impression of being significantly different from the face width configuration of a normal cavity structure iron, which may cause the user to feel uneasy. On the other hand, if it is thicker than 5.0 mm, the thickness will increase, inevitably resulting in more high specific gravity material being arranged in the upper part, making it difficult to achieve a low center of gravity.

[0047] According to a golf club equipped with the above-described head (head body), the following effects can be obtained. As described above, by using an iron-based material for the head body 10A, including the hosel portion 60, and forming the entire head body 10A with an L-shaped cross section, it is possible to thin the face portion 70 (down to about 1.5 mm) while maintaining the strength to withstand impact, and this thinning makes it possible to achieve a good balance between improved resilience (improved distance) and weight reduction. In addition, by welding the high-specific-gravity material 32 with a specific gravity of 17 or more to the rear end of the sole region 30a, it is possible to achieve a low center of gravity while maintaining high resilience.

[0048] The head structure described above was tested using a robot testing machine to verify the ball's initial velocity, launch angle, spin rate, trajectory height, and carry, with the results shown in Table 2 below. In this test, two golf clubs were prepared, each with an identical L-shaped head body made of iron-based material with a loft angle of 25° and a shaft of the same structure. One of the golf clubs had tungsten with a specific gravity of 17 welded to its head body (referred to as the new structure), while the other had tungsten with a specific gravity of 9.3 welded to its head body, as in conventional technology (referred to as the comparative structure).

[0049] [Table 2]

[0050] Typically, the face of a golf club head can be made higher in initial velocity if the center of gravity is lowered, even if the thickness and coefficient of restitution remain the same. The head body 10A of this embodiment, which has a new structure, has an L-shaped, low center of gravity, which increases initial velocity without increasing the coefficient of restitution. Furthermore, the lower center of gravity increases the launch angle, resulting in a high trajectory and a reduced amount of spin (backspin). That is, when hitting the ball, the head rotates in a direction that reduces the loft angle due to impact, resulting in a certain amount of backspin. However, lowering the center of gravity of the head body reduces the amount of backspin, making it possible to transfer energy to the ball without loss (improving distance).

[0051] The iron-type golf club and its head according to the present invention have been described above, but the structure and appearance of the present invention can be modified as appropriate as long as the head body is constructed using a high-strength iron-based material, the face portion is made thinner than conventional light metal materials, and a high-specific-gravity material with a specific gravity of 17 or more is welded to the rear end of the sole portion. [Explanation of symbols]

[0052] 1. Golf club 10 Head (Golf Club Head) 10A head body 20 Top Section 30 Sole 30a sole area 32 High specific gravity materials 40 Toe 50 heel 60 Hosel part 70 Face

Claims

1. An iron-type golf club head having a head body in which a top portion, a sole portion, a toe portion, a heel portion, a hosel portion, and a face portion are integrally formed from an iron-based material, When the golf club having the iron-type golf club head attached thereto is in an address posture such that the axis X of the hosel portion is vertical when viewed from the toe side and forms a set lie angle with respect to a reference horizontal plane P when viewed from the front, The height of the head body from the reference horizontal plane P to the highest point when viewed from the front is defined as H, The height of the center of gravity from the reference horizontal plane P to the center of gravity when viewed from the front is H1, The height H1 of the center of gravity / the height H of the head body is a low center of gravity ratio. The sole width of the sole region of the sole portion bent from the lower end of the face portion toward the back side is L2, When defined as the sole portion has a sole region at a lower end of the face portion and a sole width L2 of 4 mm or more, and a high-specific-gravity material extending in a toe-heel direction and having a specific gravity of 16 or more is welded to a rear end of the sole region; the height H of the head body is 52 mm or more, the height H1 of the center of gravity is 17.0 mm or less, and the low center of gravity ratio H1 / H is 32% or less; a thickness of a lower end region of the face portion is 2.2 mm or less, and the sole region is formed integrally with the face portion and bent toward a back side, the thickness of the sole region being equal to or less than the thickness of the lower end region of the face portion; The iron-type golf club head is characterized in that the high specific gravity material weighs 85 g or more and is disposed in a portion of the head that is 13.5% or less of the head height H.

2. An iron-type golf club head as described in Claim 1, characterized in that the high-density material extends from both ends of the sole side in the toe-heel direction to the intermediate regions of the toe and heel portions, respectively.

3. The back side of the face portion has a cavity structure, 2. The iron-type golf club head according to claim 1, wherein the frame width of the top portion when viewed from the back side is set to 2.5 mm to 3.5 mm, the frame width of the toe portion when viewed from the back side is set to 2.5 mm to 5.0 mm, and the frame width of the sole portion is set to 2.0 mm to 5.0 mm.

4. An iron-type golf club head as described in Claim 1, characterized in that a rising portion that rises as it transitions to the back is formed on the rear end side of the sole region.

5. The high-specific-gravity material is directly welded to the rear end of the sole region, In the address posture, When the angle formed by a tangent line La of the sole surface at the center Ca of the effective sole width Wa and a reference horizontal plane P is defined as a sole angle β within a plane including a center line (SL) perpendicular to the score line at the center in the toe-heel direction of the score line formed on the face surface of the face portion, 5. The iron-type golf club head according to claim 4, wherein the sole angle β is set to a range of −2° to 6°.

6. An iron-type golf club head as described in Claim 1, characterized in that a rib extending in the toe-heel direction is formed in the middle of the back surface of the face portion, and the area below the rib is thick and the area above the rib is thin.

7. An iron-type golf club head as described in claim 1, characterized in that a decorative member having a lower specific gravity than the main body member is fixed to the upper surface of the high specific gravity material.

8. A golf club equipped with an iron-type golf club head according to any one of claims 1 to 7.

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