JP2016007443A - Iron golf club head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve repulsion performance without lowering durability performance.SOLUTION: An iron golf club comprises a face member 11 including a face F, and a head body 10 to which the face member 11 is fitted. The face member 11 includes the face F, a back plane 17 as a plane in the opposite side thereof, and the thickness from the face F to the back plane 17. The face member 11 includes a first part 20 in an outer peripheral side where the back plane 17 comes into contact with a face fitting part 15 and supported thereby, and a second part 21 without coming into contact with the face fitting part 15. The second part 21 includes a main portion 22 having the thickness smaller than that of the first part 20 and extending in parallel with the face F, and a sub part 23, the thickness of which gradually decreases from the first part 20 toward the main portion 22 between the main portion 22 and the first part 20.

Description

  The present invention relates to an iron type golf club head having improved resilience performance without reducing durability performance.

  Conventionally, iron-type golf club heads having excellent hitting ball resilience performance have been proposed. For example, an iron type golf club head including a face member and a head body having a face mounting portion to which the face member is attached is known. The face member includes a first portion that contacts the face mounting portion, and a second portion that is surrounded by the first portion and is not in contact with the face mounting portion, and the second portion has a smaller thickness than the first portion. have. In such a head, when the ball is hit, the second portion can freely bend toward the back side of the head, so that a large resilience performance can be obtained.

  However, although the above-described head has excellent resilience performance, there is a problem that cracks and the like are easily generated between the first portion and the second portion, and durability performance is low.

JP 2012-65803 A

  The present invention has been devised in view of the above circumstances, and provides an iron type golf club head with improved resilience performance without lowering durability performance based on improving the shape of the face member. The main purpose is to do.

  The present invention is an iron-type golf club head including a face member having a face which is a surface for hitting a ball, and a head body having a face mounting portion to which the face member is attached, It has a front surface forming a face, a back surface as an opposite surface, and a thickness from the front surface to the back surface, and the back surface of the face member is supported in contact with the face mounting portion. A first portion and a second portion surrounded by the first portion and not in contact with the face mounting portion, the second portion being smaller in thickness than the first portion and parallel to the face A main part having the back surface that extends, and a sub part in which the thickness gradually decreases from the first part toward the main part between the main part and the first part. Featuring There.

  In the iron type golf club head according to the present invention, it is desirable that the sub-portion is tapered from the first portion toward the main portion in a head cross section including a perpendicular line extending from the center of gravity of the head to the face.

  In the iron type golf club head according to the present invention, it is preferable that the back surface of the sub part extends at an angle of 35 to 60 ° with respect to the thickness direction of the face member.

  In the iron type golf club head according to the present invention, it is desirable that the face member has a difference between a thickness of the first portion and a thickness of the main portion of the second portion of 0.3 to 1.0 mm.

  In the iron type golf club head according to the present invention, in the cross section of the head including a perpendicular line from the center of gravity of the head to the face, the sub part has a length of 0.3 to 1.0 mm along the face. It is desirable.

  In the iron type golf club head according to the present invention, the main portion of the face member includes a first main portion and a second main portion formed on the inner side and having a thickness smaller than that of the first main portion. It is desirable that

  In the iron type golf club head according to the present invention, in the cross section of the head including a perpendicular line extending from the center of gravity of the head to the face, the sub part has a chamfered arc at a corner part formed by the first part and the main part. It is desirable to include.

  You may comprise the iron-type golf club set provided with the iron-type golf club head concerning the said invention. In this case, the iron type golf club set includes iron type golf clubs of at least two counts having different loft angles, and the sub part in the head of the iron type golf club is in the head of the golf club having the smaller number It is preferable that the set is an iron type golf club set formed on the top side and the sole side of the face member.

  In the iron-type golf club set of the present invention, the sub-portion may be formed only on the sole side of the face member in a golf club head having a larger count.

  The iron type golf club head of the present invention includes a face member having a face which is a surface for hitting a ball, and a head body having a face mounting portion to which the face member is attached. The face member has a face, a back surface opposite to the face, and a thickness from the face to the back surface. The face member includes a first portion on the outer peripheral side whose back surface is supported by being in contact with the face mounting portion, and a second portion that is surrounded by the first portion and is not in contact with the face mounting portion. Such a second portion provides a large resilience performance in order to ensure a region where the face member can bend freely behind the head when the ball is hit.

  The second part has a thickness that is smaller than the first part and extends in parallel with the face, and the thickness gradually decreases from the first part toward the main part between the main part and the first part. And a sub part. Such a sub-portion can prevent stress concentration between the first portion and the second portion. Therefore, the iron type golf club head of the present invention has excellent durability performance and resilience performance.

It is a front view of the standard state of the iron type golf club head of one embodiment of the present invention. It is a rear view of FIG. It is the sectional view on the AA line of FIG. 1 is an exploded perspective view of an iron type golf club head of an embodiment. FIG. 4 is a partially enlarged view of the sole side in FIG. 3. It is sectional drawing by the side of the sole of the face member of other embodiment of this invention. It is sectional drawing by the side of the sole of the face member of further another embodiment of this invention. (A) is sectional drawing of the iron type golf club head which shows embodiment of a comparative example, (b) is an enlarged view at the sole side of the face member of (a).

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a front view of a reference state of an iron type golf club head 1 of the present embodiment. FIG. 2 shows a rear view of FIG. FIG. 3 shows a cross-sectional view taken along line AA of FIG. FIG. 4 is an exploded perspective view of the iron type golf club head 1 before assembly.

  In the present specification, the reference state of an iron type golf club head (hereinafter sometimes simply referred to as “head”) 1 is the lie angle α and loft angle β defined by the head 1 (see FIG. 3 for the loft angle β). It is in a state where it is placed on the horizontal plane HP. In the present specification, the head 1 is assumed to be in a reference state unless otherwise specified. “The specified lie angle” and “the specified loft angle” mean the lie angle and the loft angle defined for the head 1.

  The lie angle α and the loft angle β of the head 1 are not particularly limited. Typically, the lie angle α may be determined in a range of, for example, 50 to 70 degrees, and the loft angle β may be determined in a range of, for example, 15 to 70 degrees.

  As shown in FIGS. 1 and 2, the head 1 of the present embodiment includes a head base 2 and a hosel portion 3.

  The head substrate 2 is partitioned by a face F, a face back surface 4, and a head outer peripheral surface 5.

  The face F is a surface for hitting a ball. The face F is a portion formed substantially in a single plane except for the impact area marking 6. As the impact area marking 6, for example, a groove is typically adopted, but a punch mark or the like may be used. The face F has a sweet spot SS that is an intersection of a perpendicular drawn from the head center of gravity G to the face F.

  As shown in FIG. 2, the face back surface 4 is a surface opposite to the face F. A cavity C is formed in the face back surface 4 of the present embodiment.

  As shown in FIG. 3, the head outer peripheral surface 5 connects the face F and the face back surface 4. As shown in FIG. 1, the head outer peripheral surface 5 includes a top 7, a sole 8 and a toe surface 9.

  The top 7 extends rearward from the upper edge of the face F so as to form the upper surface of the head. With respect to the front-rear direction of the head, the face side is the front and the back side is the rear. Regarding the vertical direction of the head, the direction close to the horizontal plane HP is the lower side, and the direction away from the horizontal plane is the upper side.

  The sole 8 extends rearward from the lower edge of the face F so as to form the bottom surface of the head.

  The toe surface 9 connects the top 7 and the sole 8. The toe surface 9 is formed in an arc shape that is convex toward the toe side.

  The upper edge of the face F includes a toe side high point P1, which is the uppermost position, and a heel side low point P2, which is the lowermost position. When a vertical plane VP1 passing through the toe side high point P1 and perpendicular to the face F and a vertical plane VP2 passing through the heel side low point P2 and perpendicular to the face F are defined, the top 7 Of these, on the upper surface side of the head, the portion extends between the vertical surface VP1 on the toe side and the vertical surface VP2 on the heel side. The sole 8 is a portion of the head outer peripheral surface 5 that extends between the toe-side vertical surface VP1 and the heel-side vertical surface VP2 on the head bottom surface side.

  The hosel part 3 is cylindrical. The hosel portion 3 is provided on the heel side of the head base 2. The hosel portion 3 has a shaft insertion hole 3a having a bottom. A shaft (not shown) is attached to the shaft insertion hole 3a. When obtaining the head 1 in the reference state, the shaft center line CL of the shaft insertion hole 3a may be used as the shaft center line of the shaft.

  The head 1 of this embodiment includes a head main body 10 and a face member 11 attached to the head main body 10 as constituent members.

  The head main body 10 of the present embodiment is configured by joining a face receiving portion 12 and a weight member 13. However, the head body 10 is not limited to such an embodiment, and may be an integrally molded product.

  As shown in FIG. 4, the face receiving portion 12 of the present embodiment extends in an annular shape so as to define an opening O penetrating in the front-rear direction.

  The face receiving portion 12 includes, for example, a top portion frame 12a, a sole portion frame 12b, a toe portion frame 12c, and a heel portion frame 12d.

  The top part frame 12 a forms the top 7.

  The sole portion frame 12b partially forms the sole 8. In order to distribute more mass to the lower part of the head, it is desirable that the sole frame 12b is formed to have the largest width in the front-rear direction of the head. The sole frame 12b is formed with a concave groove 14 extending in the toe-heel direction by cutting out the sole 8.

  The toe part frame 12 c connects the top part frame 12 a and the sole part frame 12 b on the toe side to form a toe surface 9.

  The heel part frame 12d connects the top part frame 12a and the sole part frame 12b on the heel side. The heel part frame 12d is configured by a flat surface in which a heel side end face 12h extends vertically. However, a part of the groove 14 may be formed on the end surface 12h, or a recess (not shown) may be formed separately from the groove 14. This recess is formed so as not to be visually recognized after the head 1 is assembled.

  The face receiving portion 12 includes a face attaching portion 15 to which the face member 11 is attached on the front side. The face mounting portion 15 of the present embodiment is continuous in an annular shape along the opening O.

  As shown in FIG. 3, the face attachment portion 15 includes an inward surface 15 a facing the center side of the head 1 and a forward surface 15 b facing the face side. On the inward surface 15a, for example, a convex portion 19 for restricting the movement of the face member 11 is formed on the front side thereof. The convex portion 19 protrudes toward the center side of the head 1. In a preferred embodiment, the convex portion 19 is formed in an annular shape along the inward surface 15a. A part of the outer peripheral surface of the face member 11 is firmly held in the space between the convex portion 19 and the forward-facing surface 15b in a retaining state. Such a convex portion 19 can be formed by, for example, so-called “caulking” in which, after the face member 11 is mounted on the face attachment portion 15, a part of the face attachment portion 15 is crushed and plastically deformed.

  In the present embodiment, the face member 11 is fixed to the face mounting portion 15 by the above-described caulking. As another embodiment, the face member 11 may be fixed to the face attachment portion 15 by a joining means such as adhesion, press-fitting, welding, brazing, or screwing. When the face member 11 is fixed to the face attachment portion 15, the opening O is closed.

  The face receiving portion 12 is preferably made of a material having a large specific gravity. As a result, more mass is distributed around the face F, and the sweet area is expanded. For the face receiving portion 12, for example, stainless steel, maraging steel, Ni-based alloy or soft iron is suitable.

  As shown in FIG. 4, the weight member 13 has a first weight portion 13A and a second weight portion 13B. In the present embodiment, the first weight portion 13A and the second weight portion 13B are integrally formed.

  The weight member 13 is preferably made of a material having a specific gravity greater than that of the face receiving portion 12. As the weight member 13, for example, one type or two or more types of metal materials such as stainless steel, tungsten, tungsten alloy, copper alloy, and nickel alloy are suitable. A tungsten nickel alloy is employed for the weight member 13 of the present embodiment.

  The first weight portion 13A extends the sole 8 in the toe-heel direction. The first weight portion 13A is exposed on the bottom surface of the head so as to constitute a part of the sole 8. The second weight part 13 </ b> B constitutes the hosel part 3. Therefore, the weight member 13 continuously distributes a large amount of mass at the bottom of the head 1 in the toe-heel direction, and in particular distributes a large amount of mass on the heel side.

  As shown in FIGS. 3 and 4, the shape of the first weight portion 13 </ b> A substantially matches the shape of the concave groove 14. Accordingly, the first weight portion 13A is uniquely positioned by being inserted into the groove 14.

  In this embodiment, the upper surface 13a of the first weight portion 13A extends in a plurality of steps (stepwise) toward the toe side. Such a first weight portion 13A can distribute more mass to the toe side.

  The second weight portion 13B includes, as the hosel portion 3, an outer surface 13b that constitutes the outer surface of the head 1, and a contact surface 13c that extends vertically. The contact surface 13c is formed so as to face the heel side end surface 12h of the heel portion frame 12d when the first weight portion 13A is inserted into the concave groove 14. Thereafter, for example, the face receiving portion 12 and the hosel portion 3 are fixed by welding or the like.

  The face member 11 includes a front surface 16, a back surface 17, and an outer peripheral surface 18.

  The front surface 16 of the face member 11 is a surface constituting the face F, and is a surface visually recognized when the head 1 is viewed from the front. The front face 16 of the face member 11 of the present embodiment constitutes a main part of the face F as a preferred aspect. The front surface 16 of the face member 11 preferably has an area of 60% or more, more preferably 70% or more of the total area of the face F. As shown in FIG. 1, the front surface 16 of the face member 11 is provided with an impact area marking 6 such as a groove or a punch mark. The front surface 16 substantially constitutes one plane except for the impact area marking 6.

  As shown in FIG. 3, the back surface 17 of the face member 11 is a surface opposite to the front surface 16 of the face member 11. In other words, the back surface 17 of the face member 11 is a surface that is visible when the face member 11 alone is viewed from the opposite side of the front surface 16. The back surface 17 of the present embodiment is configured to include several different surfaces. Thereby, the face member 11 has different thicknesses. In FIG. 3, the thickness at a certain position of the face member 11 is representatively represented by the symbol “T”. The thickness T of the face member 11 is measured at a position excluding the impact area marking 6 (shown in FIG. 1) (or assuming that there is no impact area marking 6).

  The outer peripheral surface 18 of the face member 11 is a surface connecting the front surface 16 and the back surface 17 and is continuous in an annular shape. The outer peripheral surface 18 of the face member 11 of the present embodiment is formed in a substantially stepped cross section so that a flange portion 27 protruding outward from the head is provided on the back surface 17 side. The flange portion 27 is held in a space between the convex portion 19 of the face mounting portion 15 and the forward facing surface 15b.

  As shown in FIG. 4, the outer peripheral surface 18 includes a top portion surface 18a, a sole portion surface 18b, a toe portion surface 18c, and a heel portion surface 18d.

  The top portion surface 18 a extends substantially parallel to the top 7. The sole surface 18b extends substantially parallel to the sole 8. The toe portion surface 18 c extends substantially parallel to the toe surface 9. The heel portion surface 18d is formed, for example, on the toe side of the heel side vertical surface VP2 (shown in FIG. 1) and extends substantially vertically between the top portion surface 18a and the sole portion surface 18b.

  In order to improve the resilience performance, for example, a titanium alloy having a low specific gravity and a high strength is preferably used for the face member 11.

  FIG. 5 is a partially enlarged view of the sole side in FIG. 3 and corresponds to a partial cross-sectional view of the head 1 including a perpendicular line extending from the head center of gravity G (shown in FIG. 3) to the face F. As shown in FIG. 5, the face member 11 includes a first portion 20 and a second portion 21.

  The first portion 20 of the face member 11 means a portion of the face member 11 where the back surface 17 is supported by being in contact with the face mounting portion 15. The first portion 20 of the present embodiment is provided on the outer peripheral surface 18 side of the face member 11, and is preferably provided in an annular shape along the outer peripheral surface 18 of the face member 11. The first portion 20 is also supported by being in contact with the inward surface 15 a of the face attachment portion 15. By such a first portion 20, the face member 11 is firmly fixed to the face mounting portion 15.

  The first portion 20 of the present embodiment is formed with a substantially constant thickness T1 except for the flange portion 27 provided for caulking. In order to improve the durability performance at the joint portion between the face member 11 and the face attachment portion 15, the thickness T1 of the first portion 20 is preferably 2.5 to 4.0 mm.

The second portion 21 of the face member 11 means a portion of the face member 11 that is surrounded by the first portion 20 but is not in contact with the face attachment portion 15. In FIG. 5, for easy understanding, a boundary J <b> 1 between the first portion 20 and the second portion 21 is indicated by a virtual line. Since the second portion 21 can freely bend toward the rear of the head when the ball is hit, it provides excellent resilience performance.

  The second part 21 has a main part 22 and a sub part 23. The main portion 22 is a portion having a back surface 17 extending in parallel with the face F with a thickness T2 smaller than the thickness T1 of the first portion 20. Such a main portion 22 increases the amount of bending of the face member 11 when the ball is hit, and further improves the resilience performance.

  The main portion 22 of this embodiment includes a thin portion 24 and a thick portion 25 having a thickness larger than that of the thin portion 24. The thin portion 24 of the present embodiment is formed with a constant thickness T2a. The thickness T2a is the smallest among the face members 11. The thin portion 24 occupies the largest area in the face member 11. Such a thin-walled portion 24 is useful for providing greater deflection to the face member 11 when a ball is hit. The thick portion 25 of the present embodiment is provided on the outer peripheral side of the head 1 with respect to the thin portion 24. In FIG. 5, a boundary J <b> 2 between the thin portion 24 and the thick portion 25 is indicated by an imaginary line. However, the main portion 22 may have a single thickness continuously.

  Further, the thin portion 24 and the thick portion 25 are connected in a stepped shape via a face Fa perpendicular to the face F. Such a thin portion 24 and a thick portion 25 improve the resilience performance and durability performance of the face member 11 in a well-balanced manner. About the difference in thickness (T2b-T2a) between the thin portion 24 and the thick portion 25, if the thickness is excessively large, the durability of the face member 11 may be lowered. It is said.

  The sub portion 23 is a portion of the second portion 21 that gradually decreases in thickness from the first portion 20 toward the main portion 22 between the main portion 22 and the first portion 20. In FIG. 5, a boundary J3 between the sub part 23 and the main part 22 is indicated by an imaginary line. The sub part 23 can prevent stress concentration between the first part 20 and the main part 22. Therefore, the durability performance of the face member 11 is improved. When the face member 11 and the head main body 10 are fixed by caulking as in the present embodiment, the sub-portion 23 can effectively relieve stress concentration due to the load during the caulking process.

  The sub portion 23 of the present embodiment has a tapered shape in which the thickness gradually decreases from the first portion 20 toward the main portion 22. Therefore, when the face member 11 is attached to the face attaching portion 15 by caulking as in the present embodiment, the durability is particularly effective. That is, since the sub part 23 is tapered, the thickness from the caulking part to the taper part is secured. Thereby, the strength of the face member 11 is increased and the durability is improved.

  In the cross section as shown in FIG. 5, the back surface of the sub-portion 23 desirably extends at an angle θ of 35 to 60 ° with respect to the thickness direction of the face member 11, for example. When the angle θ of the sub portion 23 is less than 35 °, stress concentration between the first portion 20 and the main portion 22 cannot be effectively prevented, and the durability performance may be deteriorated. When the angle θ of the sub-part 23 exceeds 60 °, the area of the main part 22 becomes small, and the resilience performance may be reduced. The angle θ of the sub part 23 is more preferably 40 to 55 °.

  The change in the thickness of the sub-portion 23 (in this embodiment, the difference between the thickness T1 of the first portion 20 and the thickness T2b of the thick portion 25 of the main portion 22 (T1-T2b)) is preferably 0.3 to 1.0 mm. When the change in the thickness of the sub-part 23 (T1-T2b) is less than 0.3 mm, the second part 21 comes into contact with the forward-facing surface 15b when hitting the ball, and the resilience performance may be deteriorated. When the change in the thickness of the sub-portion 23 (T1-T2b) exceeds 1.0 mm, the thickness T2 of the second portion 21 becomes small, and the durability performance of the face member 11 may be deteriorated.

  In order to effectively exhibit the above-described action, the length La along the face F of the sub-part 23 is preferably 0.3 to 1.0 mm. When the length La of the sub part 23 is less than 0.3 mm, there is a possibility that sufficient relaxation of stress concentration cannot be obtained. When the length La of the sub part 23 exceeds 1.0 mm, the resilience performance of the head 1 may be deteriorated. The length La is the length in the head section.

  The position where the sub part 23 is provided is not particularly limited. For example, when the first portion 20 is formed in an annular shape as in the present embodiment, the sub-portion 23 can be provided at an arbitrary position between the first portion 20 and the main portion 22. For example, the sub part 23 may be formed continuously in an annular shape. When the sub-portion 23 is provided in a non-annular shape, for example, it may be provided in the vicinity of at least one of the top portion surface 18a, the toe portion surface 18c, and the heel portion surface 18d of the face member 11. Furthermore, in a preferable aspect, it is provided in the sole part side and / or the top part side which are easy to receive big force at the time of impact.

  FIG. 6 shows a sectional view of a portion of the face member 11 on the sole 8 side as still another embodiment of the sub-portion 23. 6 corresponds to a partial cross-sectional view of the head 1 including a perpendicular line extending from the head center of gravity G (shown in FIG. 3) to the face F. FIG. As shown in FIG. 6, the back surface of the sub-portion 23 includes an arc R at a corner portion 26 formed by the first portion 20 and the main portion 22. The sub-part 23 having such a configuration also effectively reduces the stress concentration between the first part 20 and the main part 22 and improves the durability of the face member 11. The arc R of the present embodiment extends so as to protrude toward the face F side. The arc R may be formed by a plurality of arcs. The parts not shown in FIG. 6 are the same as those of the embodiment of FIGS.

  FIG. 7 shows a sectional view of a portion of the face member 11 on the sole 8 side as still another embodiment of the sub-portion 23. 7 corresponds to a partial cross-sectional view of the head 1 including a perpendicular line extending from the head center of gravity G (shown in FIG. 3) to the face F. FIG. As shown in FIG. 7, in this embodiment, the back surface of the sub part 23 includes an arc part Ra and a straight part Sa. The arc portion Ra includes a first arc R1 on the first portion 20 side and a second arc R2 on the main portion 22 side. The straight line portion Sa connects the first arc R1 and the second arc R2. The first arc R1 and the second arc R2 are preferably connected smoothly by a straight line or a curve. The parts not shown in FIG. 7 are the same as in the previous embodiment.

  Further, the sub-part 23 may be formed in, for example, a bent tapered shape (not shown) in which straight lines with different angles θ are combined.

  For example, a golf club set may be configured in the iron type golf club of the above embodiment. In this case, the golf club set includes at least two iron type golf clubs having different loft angles. Although not shown, in the iron type golf club head, the above-described sub-part 23 is formed on both the top 7 side and the sole 8 side of the face member 11 in the smaller golf club head. Generally, in a golf club with a small count, the coefficient of restitution tends to be small. Therefore, there is a tendency that the difference in the flight distance is less likely to occur between the counts of golf clubs with smaller counts. On the other hand, by forming the sub-portion 23 in this way, a difference in flight distance between counts is easily generated.

  Similarly, in the iron-type golf club of the above-described embodiment, the above-described golf club set is configured. Further, in the head of the golf club having the larger count, the auxiliary portion 23 is only on the sole 8 side of the face member 11. It may be formed. By configuring the iron-type golf club set in this way, it is possible to easily make a difference in flight distance between counts.

  As mentioned above, although embodiment of this invention was described in detail, this invention is not limited to said specific embodiment, It implements by changing into various aspects.

A club head having the basic structure shown in FIGS. 1 to 4 was prototyped based on the specifications shown in Table 1, and the resilience performance and durability performance of each sample head were tested. The shape of the head of the comparative example is as shown in FIGS. 8 (a) and 8 (b). The main common specifications and test methods for each head are as follows.
Head: No. 6 iron lie angle α: 61.5 °
Loft angle β: 27 °
Material of weight member: Tungsten alloy (specific gravity: 9.5)
Material of face member: Titanium alloy (specific gravity: 4.38)
Material of face receiving part: SUS630 (specific gravity: 7.78)
Length Lb in the face direction of the flange portion (shown in FIG. 5): 0.5 mm
Flange thickness Ta (shown in FIG. 5): 2.05 mm
Length L1 of the first portion in the face direction (shown in FIG. 5): 2.0 mm
The test method is as follows.

<Rebound performance>
U. S. G. A. The coefficient of restitution was calculated according to the Procedure for Measuring the Velocity Ratio of a Club Head for Conformance to Rule 4-1e, Revision 2 (February 8, 1999). However, in addition to the sweet spot of the face, the ball collision position is the top side position, the toe side position, and the heel side position separated by 10 mm along the face from the sweet spot to the top side, sole side, toe side, and heel side. A total of 5 locations. The result is a value obtained by setting the average value of five locations tested in Comparative Example 1 to 100. The larger the value, the better the resilience performance.

<Durability>
A carbon shaft (MP-600, Flex S) manufactured by Dunlop Sports Co., Ltd. was attached to each test head, and a 37.5 inch iron type golf club was prototyped. These were attached to a swing robot manufactured by Miyamae Co., Ltd., and a golf ball was hit at a head speed of 50 m / s, and the number of hits until the face member was damaged (the upper limit was 10,000 shots) was measured. The presence or absence of breakage was performed by observing the occurrence of cracks between the first part and the second part of the face member with the naked eye. The greater the number of hits, the better the durability performance.
The test results are shown in Table 1.

  As a result of the test, as shown in FIG. 3, the head of the example in which the thickness of the sub part gradually decreases from the first part toward the main part is more durable than the head of the comparative example of FIG. It was confirmed that the resilience performance was improved while maintaining the property. In Example 2, although the durability performance is slightly lowered, the result is that the quality of the golf club head is sufficiently satisfied.

DESCRIPTION OF SYMBOLS 1 Iron type golf club head 10 Head main body 11 Face member 17 Back surface 15 Face attaching part 20 1st part 21 2nd part 22 Main part 23 Sub part F Face

Claims (9)

An iron-type golf club head including a face member having a face that hits a ball, and a head body having a face mounting portion to which the face member is mounted,
The face member has a front surface forming the face, a back surface opposite to the front surface, and a thickness from the front surface to the back surface,
The face member is
A first portion supported by the back surface in contact with the face mounting portion;
A second part surrounded by the first part and not in contact with the face mounting part,
The second part is
A main portion having the back surface extending in parallel with the face with a thickness smaller than the first portion;
An iron-type golf club head comprising a sub-portion having a gradually decreasing thickness from the first portion toward the main portion between the main portion and the first portion. . In the cross section of the head including the perpendicular line from the center of gravity of the head to the face,
The iron-type golf club head according to claim 1, wherein the sub-portion is tapered from the first portion toward the main portion.   3. The iron type golf club head according to claim 1, wherein the back surface of the sub part extends at an angle of 35 to 60 ° with respect to the thickness direction of the face member.   4. The iron type golf club according to claim 1, wherein the face member has a difference between a thickness of the first portion and a thickness of the main portion of the second portion of 0.3 to 1.0 mm. 5. head. In the cross section of the head including the perpendicular line from the center of gravity of the head to the face,
The iron type golf club head according to claim 1, wherein the sub part has a length of 0.3 to 1.0 mm along the face.   The main part of the face member includes a first main part and a second main part formed inside thereof and having a thickness smaller than that of the first main part. The described iron-type golf club head. In the cross section of the head including the perpendicular line from the center of gravity of the head to the face,
The iron-type golf club head according to claim 1, wherein the sub-portion includes a chamfered arc at a corner portion formed by the first portion and the main portion. An iron type golf club set including the iron type golf club head according to claim 1,
The iron type golf club set includes an iron type golf club of at least two counts having different loft angles,
In the iron-type golf club head, the sub-portion is
An iron-type golf club set formed on the top side and the sole side of the face member in a golf club head having a smaller count. The iron type golf club set according to claim 8, further comprising:
An iron-type golf club set in which the sub-portion is formed only on the sole side of the face member in the golf club head having a larger count.

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