Iron golf club head

Abstract

This iron golf club head (100) comprises a face part (10), a toe part (20), and a heel part (30). The face part (10) includes a first part (13), a second part (14) surrounding the first part (13), and a third part (15) surrounding the second part (14). In a face-back direction in which a face surface (11) and a back surface (12) face each other, the thickness of the first part (13) is greater than that of the second part (14). The second part (14) includes a first region (141), a second region (142), and a third region (143).

Description

iron golf club head

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

[0002] Iron golf club heads are required to have both high resilience and durability. To this end, it has been proposed to provide thin and thick portions on the face of an iron golf club head. In this case, high resilience due to the thin portions and durability due to the thick portions are both achieved. Japanese Patent No. 4298024 (Patent Document 1) describes an iron golf club head having thin and thick portions on the face.

[0003] Patent No. 4298024

[0004] The iron golf club head described in the above publication has a problem in that stress concentration occurs at the boundary between the thin-walled portion and the thick-walled portion.

[0005] The present invention has been made in view of the above-mentioned problems, and its object is to provide an iron golf club head that is capable of achieving both high resilience and durability while suppressing stress concentration.

[0006] The iron golf club head of the present invention includes a face portion having a face surface and a back surface, a toe portion continuous with the face portion, and a heel portion continuous with the face portion and facing the toe portion across the face portion. The face portion includes a first portion, a second portion surrounding the first portion, and a third portion surrounding the second portion. The first portion has a thickness greater than that of the second portion in a face-back direction in which the face surface and the back surface face each other. The first portion is configured flat on the back surface. The second portion includes a first region surrounding the first portion, a second region connected to the first region in a curvature continuation and surrounding the first region, and a third region connected to the second region in a curvature continuation and surrounding the second region. The thickness of the first region in the face-back direction gradually decreases from the first portion toward the second region, and the first region is curved in the face-back direction so as to protrude from the face surface toward the back surface. The second region gradually decreases in thickness in the face-back direction from the first region toward the third region, and is curved in the face-back direction so as to protrude from the back surface toward the face surface. The third region gradually increases in thickness in the face-back direction from the second region toward the third region, and is curved in the face-back direction so as to protrude from the back surface toward the face surface.

[0007] The iron golf club head of the present invention can achieve both high resilience and durability, and can also suppress stress concentration.

[0008] FIG. 3 is a front view schematically showing the configuration of an iron golf club head according to an embodiment. FIG. 4 is a rear view schematically showing the configuration of an iron golf club head according to an embodiment. FIG. 5 is a right side view schematically showing the configuration of an iron golf club head according to an embodiment. FIG. 6 is a cross-sectional perspective view taken along line IV-IV of FIG. 3. FIG. 7 is a cross-sectional perspective view taken along line V-V of FIG. 2. FIG. 8 is a cross-sectional perspective view taken along line VI-VI of FIG. 2. FIG. 9 is a perspective view schematically showing the back surface of the face portion of an iron golf club according to an embodiment. FIG. 10 is a rear view schematically showing the configuration of an iron golf club according to an embodiment.

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Unless otherwise specified, the same or corresponding parts in the following drawings will be designated by the same reference numerals, and the description thereof will not be repeated.

[0010] An iron golf club head 100 according to an embodiment will be described with reference to FIGS.

[0011] 1 and 2, the iron golf club head 100 according to the embodiment mainly includes a face portion 10, a toe portion 20, and a heel portion 30. The iron golf club head 100 also includes a top edge portion 40, a sole portion 50, a hosel portion 60, and a cavity wall portion 70.

[0012] The face portion 10 has a face surface 11 and a back surface 12. The face surface 11 is disposed on the front side of the face portion 10. The face surface 11 constitutes a ball-hitting surface. A plurality of scorelines 11a are provided on the face surface 11. Each of the plurality of scorelines 11a is provided continuously on the face surface 11.

[0013] Each of the plurality of scorelines 11a extends in a toe-heel direction in which the toe portion 20 and the heel portion 30 face each other. Each of the plurality of scorelines 11a is provided linearly in a direction crossing the face surface 11. The plurality of scorelines 11a are provided at intervals in a top-sole direction in which the top edge portion 40 and the sole portion 50 face each other. The plurality of scorelines 11a are provided at approximately equal intervals in a direction crossing the face surface 11.

[0014] The back surface 12 is located behind (on the back side of) the face surface 11. The back surface 12 is located on the opposite side to the face surface 11.

[0015] The toe portion 20 is a portion that connects the top edge portion 40 on the side away from the hosel portion 60 to the sole portion 50. The toe portion 20 is continuous with the face portion 10. The heel portion 30 is a portion that extends from the lower end of the hosel portion 60 to the sole portion 50. The heel portion 30 is continuous with the face portion 10. The heel portion 30 faces the toe portion 20 with the face portion 10 in between.

[0016] The top edge portion 40 is a portion that constitutes the upper edge of the iron golf club head 100, extending from the hosel portion 60 to the toe portion 20. The sole portion 50 is a portion that constitutes the bottom of the iron golf club head 100. The hosel portion 60 is connected to the heel portion 30. The hosel portion 60 is a portion to which a shaft is connected. The hosel portion 60 includes a region that is bent when adjusting the lie angle and loft angle.

[0017] The face portion 10 and the hosel portion 60 are made of the same material. The material of the face portion 10 and the hosel portion 60 is chrome molybdenum steel or nickel chrome molybdenum steel. The material of the face portion 10 and the hosel portion 60 is preferably nickel chrome molybdenum steel. The face portion 10 other than the face surface 11 of the iron golf club head 100 according to the embodiment is made of the same material as the face surface 11, but may be made of a different material from the face surface 11.

[0018] The face portion 10 and the hosel portion 60 may be formed by casting or forging. For example, the iron golf club head 100 according to the embodiment has a one-piece casting structure.

[0019] The difference in hardness between the face portion 10 and the hosel portion 60 is a Vickers hardness (HV) of 200 or more. The hardness of the face portion 10 is higher than the hardness of the hosel portion 60. The hardness of the face portion 10 is the hardness near the scoreline center of the face portion 10. The Vickers hardness is a value measured at a point 1 mm away from the face surface. The hardness of the hosel portion 60 is the hardness at a point approximately 30 mm away from the hosel end. The Vickers hardness is a value measured at a point 2 mm away from the surface of the hosel portion 60.

[0020] 2 and 3 , the cavity wall portion 70 surrounds the periphery of the back surface 12. The cavity wall portion 70 is configured to extend along the toe portion 20, the heel portion 30, the top edge portion 40, and the sole portion 50. The cavity wall portion 70 defines a cavity 80. The cavity 80 is surrounded by the cavity wall portion 70.

[0021] As shown in FIGS. 4 to 7, the face portion 10 includes a first portion 13, a second portion 14, and a third portion 15.

[0022] The first portion 13 is configured flat on the back surface 12. The thickness of the first portion 13 is uniform. The thickness of the first portion 13 in the face-back direction, in which the face surface 11 and the back surface 12 face each other, is greater than that of the second portion 14. The thickness of the first portion 13 in the face-back direction, in which the face surface 11 and the back surface 12 face each other, may be greater than that of the third portion 15. The sweet spot SS of the face portion 10 is located, for example, in the first portion 13. The center of the first portion 13 is located, for example, closer to the toe portion 20 than the scoreline center. The lower edge of the first portion 13 is located 15 mm or more closer to the top edge portion 40 from the leading edge in the top-sole direction. In the height direction, at least one of the fifth and sixth scorelines from the leading edge passes through the first portion 13. In the horizontal direction, the first portion 13 is included within a range of ±5 mm from the scoreline center.

[0023] The second portion 14 surrounds the first portion 13. The second portion 14 surrounds the entire periphery of the first portion 13. The second portion 14 is configured to have a curved surface on the back surface 12. The second portion 14 includes a first region 141, a second region 142, and a third region 143. The first region 141 surrounds the first portion 13. The first region 141 surrounds the entire periphery of the first portion 13.

[0024] The second region 142 is connected to the first region 141 in a curvature continuous manner. In other words, the curvatures at the end points of the curves of the first region 141 and the second region 142 are the same. The second region 142 surrounds the first region 141. The second region 142 surrounds the entire periphery of the first region 141.

[0025] The third region 143 is connected to the second region 142 in a curvature continuous manner. In other words, the curvatures at the end points of the curves of the second region 142 and the third region 143 are the same. The third region 143 surrounds the second region. The third region 143 surrounds the entire periphery of the second region 142.

[0026] The third portion 15 surrounds the second portion 14. The third portion 15 surrounds the entire periphery of the second portion 14. The third portion 15 is configured to be flat on the back surface 12. The thickness of the third portion 15 is uniform. In this embodiment, the thickness of the third portion 15 is thinner than the thickness of the first portion 13.

[0027] In a cross section in the toe-heel direction, the first region 141 gradually decreases in thickness in the face-back direction from the first portion 13 toward the second region 142, and is curved so as to protrude from the face surface 11 toward the back surface 12 in the face-back direction. Note that the cross section is a surface obtained by cutting the first portion 13 along a line passing through approximately the center of the first portion 13. The center of curvature of the first region 141 is located on the opposite side of the surface of the second portion 14 from the center of curvature of the second region 142. Also in the top-sole direction, the first region 141 gradually decreases in thickness in the face-back direction from the first portion 13 toward the second region 142, and is curved so as to protrude from the face surface 11 toward the back surface 12 in the face-back direction. The center of curvature of the first region 141 is located on the opposite side of the surface of the second portion 14 from the center of curvature of the second region 142.

[0028] The second region 142 has a thickness that gradually decreases in the face-back direction from the first region 141 toward the third region 143, and is curved in the face-back direction so as to protrude from the back surface 12 toward the face surface 11. The center of curvature of the second region 142 is located on the opposite side of the surface of the second part 14 from the center of curvature of the first region 141.

[0029] The third region 143 gradually increases in thickness in the face-back direction from the second region 142 toward the third part 15, and is curved in the face-back direction so as to protrude from the back surface 12 toward the face surface 11. The center of curvature of the third region 143 is located on the same side as the center of curvature of the second region 142 with respect to the surface of the second part 14.

[0030] The second portion 14 gradually becomes thinner from the third portion 15 toward the first portion 13, reaching its thinnest point, and then gradually thickens from the thinnest point, with the first portion 13 and the second portion 14 being connected while maintaining a continuous curvature. An elliptical shape obtained by collecting the thinnest points in any cross section cut by a line segment passing through the approximate center of the first portion 13 is located so as to surround the entire circumference of the second region 142. The first region 141, the second region 142, and the third region 143 do not have any portions with a constant gradient. The average gradient of the first region 141 and the second region 142 is gentler than the average gradient of the third region 143.

[0031] The thickness of the second portion 14 changes continuously in any cross section cut by a line segment passing through approximately the center of the first portion 13. There is no portion in the second portion 14 where the same thickness continues, for example, in the toe-heel direction or the top-sole direction. The thickness of the second portion 14 is not symmetrical with respect to the first portion 13.

[0032] When viewed from the back surface 12, the first portion 13 and the second portion 14 are each configured as an ellipse having a major axis. That is, the first portion 13 and the second portion 14 are each configured as an ellipse having a major axis in a planar view. The major axis of the ellipse is inclined with respect to each of the plurality of scorelines 11a. That is, when the back surface 12 is projected onto the face surface 11, the major axis of the ellipse is inclined with respect to each of the plurality of scorelines 11a. The major axis of the ellipse is inclined, for example, by 10 degrees with respect to each of the plurality of scorelines 11a.

[0033] The thickness of the first portion 13 is, for example, 2.4 mm. The thickness of the second portion 14 at its thinnest point, which is the connection point between the second region 142 and the third region 143, is, for example, 1.2 mm. The thickness of the third portion 15 is, for example, 1.7 mm.

[0034] 2 and 8, an iron golf club 200 according to an embodiment will be described. The iron golf club 200 is configured by combining the iron golf club head 100 with a shaft 201 and a grip 202. The shaft 201 and the grip 202 may be well-known shafts and grips.

[0035] 8, an iron golf club 200 according to the embodiment includes the iron golf club head 100 according to the embodiment, a shaft 201, and a grip 202. The iron golf club head 100 is attached to the shaft 201. The grip 202 is attached to the shaft 201.

[0036] 2 and 8, specifically, the shaft 201 has one end and the other end. The iron golf club head 100 is attached to one end of the shaft 201. The shaft 201 is attached to a hosel portion 60 of the iron golf club head 100. One end of the shaft 201 is inserted into the hosel portion 60. The grip 202 is attached to the other end of the shaft 201. The other end of the shaft 201 is inserted into the grip 202.

[0037] Next, the effects of the embodiment will be described. In the iron golf club head 100 according to the embodiment, the first portion 13 has a thickness in the face-back direction that is greater than that of the second portion 14. Therefore, the first portion 13 can enhance durability, and the second portion 14 can enhance high resilience. Therefore, it is possible to achieve both high resilience and durability.

[0038] The second region 142 is connected to the first region 141 in a curvature-continuous manner. The third region 143 is connected to the second region 142 in a curvature-continuous manner. The first region 141 gradually decreases in thickness in the face-back direction from the first portion 13 toward the second region 142 and curves to protrude from the face surface 11 toward the back surface 12 in the face-back direction. The second region 142 gradually decreases in thickness in the face-back direction from the first region 141 toward the third region 143 and curves to protrude from the back surface 12 toward the face surface 11 in the face-back direction. The third region 143 gradually increases in thickness in the face-back direction from the second region 142 toward the third portion 15 and curves to protrude from the back surface 12 toward the face surface 11 in the face-back direction. This allows the thickness of the second region 14 to change smoothly. Therefore, stress concentration at the boundary between the first portion 13 and the second portion 14 and at the second portion 14 can be suppressed. Furthermore, since stress concentration can be suppressed, the thickness of the second portion 14 can be reduced, thereby increasing the coefficient of restitution on off-center shots.

[0039] According to the iron golf club head 100 according to the embodiment, the thickness of the second portion 14 changes continuously in any cross section taken along a line segment passing through approximately the center of the first portion 13. Therefore, the thickness of the second portion 14 does not change discontinuously in any cross section taken along a line segment passing through approximately the center of the first portion 13. Therefore, stress concentration in the second portion 14 can be suppressed.

[0040] According to the iron golf club head 100 of this embodiment, the major axes of the elliptical shapes of the first portion 13 and the second portion 14 are inclined with respect to each of the scorelines 11a. This reduces the area where the thinnest point of the second portion 14 overlaps with each of the scorelines 11a. This increases durability. Furthermore, although the thickness is thin at the scorelines 11a, stress concentration can be suppressed, thereby suppressing cracks at the scorelines 11a.

[0041] According to the iron golf club head 100 according to the embodiment, the face portion 10 and the hosel portion 60 are made of the same material. Therefore, the face portion 10 and the hosel portion 60 can be manufactured in the same process.

[0042] In the iron golf club head 100 according to the embodiment, the material of the face portion 10 and the hosel portion 60 is nickel chrome molybdenum steel. This makes the face portion 10 harder, thereby improving durability, and allows the face portion 10 to be designed thinner, thereby improving high repulsion.

[0043] The iron golf club 200 according to the embodiment includes the iron golf club head 100 according to the embodiment. Therefore, it is possible to provide the iron golf club 200 that can achieve both high resilience and durability and suppress stress concentration.

[0044] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0045] 10 face portion, 11 face surface, 11a score line, 12 back surface, 13 first portion, 14 second portion, 15 third portion, 20 toe portion, 30 heel portion, 40 top edge portion, 50 sole portion, 60 hosel portion, 70 cavity wall portion, 80 cavity, 100 iron golf club head, 141 first region, 142 second region, 143 third region, 200 iron golf club.

Claims

1. A golf club comprising: a face portion having a face surface and a back surface; a toe portion continuous with the face portion; and a heel portion continuous with the face portion and facing the toe portion with the face portion in between; the face portion including a first portion, a second portion surrounding the first portion, and a third portion surrounding the second portion; the first portion has a thickness in a face-back direction in which the face surface and the back surface face each other that is greater than that of the second portion; the first portion is configured flat on the back surface; the second portion includes a first region surrounding the first portion, a second region connected to the first region in a curvature-continuous manner and surrounding the first region, and a third region connected to the second region in a curvature-continuous manner and surrounding the second region; the thickness of the first region in the face-back direction gradually decreases from the first portion toward the second region, and the first region is curved in the face-back direction so as to protrude from the face surface toward the back surface; an iron golf club head, wherein the second region has a thickness in the face-back direction gradually decreasing from the first region toward the third region and is curved so as to protrude from the back surface toward the face surface in the face-back direction; and the third region has a thickness in the face-back direction gradually increasing from the second region toward the third region and is curved so as to protrude from the back surface toward the face surface in the face-back direction.

2. The iron golf club head according to claim 1, wherein the thickness of said second portion varies continuously in any cross section taken along a line passing through the approximate center of said first portion.

3. An iron golf club head according to claim 2, wherein a plurality of score lines are provided on the face surface, each of the plurality of score lines extending in a toe-heel direction, and when viewed from the back surface, the first portion and the second portion are each configured in an elliptical shape having a major axis, and the major axis of the elliptical shape is inclined with respect to each of the plurality of score lines.

4. The iron golf club head according to any one of claims 1 to 3, further comprising a hosel portion connected to said heel portion, wherein said face portion and said hosel portion are made of the same material.

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