JP2007275552A - Golf club head and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a golf club head allowing to have a low center of gravity, and a manufacturing method thereof. <P>SOLUTION: The golf club head 1 comprises at least a head body 1A provided with: a face member 1B forming at least a part of a face part 3; a sole member 1C forming at least a part of a sole part 5; a face side opening part Of to which a face member 1b is fixed; and an opening part Os to which the sole member 1C is fixed, wherein a hollow part i is provided inside thereof. Each specific gravity of the face member 1B, the sole member 1C, and the head body 1A, ρf, ρs, ρm satisfy a relation of ρf≤ρm<ρs, and the sole member 1C has yield stress smaller than that of the body 1A. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a golf club head capable of lowering the center of gravity and a manufacturing method thereof.

  With the recent increase in the size of club heads, the weight that can be used for weight distribution design (hereinafter, such weight is sometimes referred to as “weight margin”) is reduced, and it is difficult to provide the center of gravity of the head at a desired position. It has become. In particular, a lower and deeper head center of gravity is required for the club head in order to improve the ball launching condition for the average golfer.

  Therefore, in recent years, it is composed of a head body having an outer shell shape and having a bottomed and dovetail recess in the sole portion, and a sole plate having a specific gravity greater than that of the head body fixed to the recess. A club head is proposed in Patent Document 1 below.

JP 2000-116826 A

  However, in the club head of Patent Document 1, since the concave portion provided in the sole portion of the head body has a bottom, this bottom portion cannot be replaced with a material having a large specific gravity. Further, since the face portion is formed integrally with the head body, the center of gravity of the head tends to be shallow. Therefore, the club head has room for further improvement in making the head center of gravity deeper and lower.

  The present invention has been devised in view of the above-described problems. In the inventions according to claims 1 to 4, the specific gravity of the face member, the sole member and the head body is specified, and the sole member is Main object of the present invention is to provide a golf club head capable of sufficiently reducing the center of gravity while ensuring the ease of mounting the sole member to the head body, based on being formed from a material having a yield stress smaller than that of the head body. It is said.

  Furthermore, in the inventions according to claims 5 to 7 of the present invention, there is provided a golf club head manufacturing method capable of manufacturing a head having a lower center of gravity as described above without damaging the head body or the like. The main purpose.

According to the first aspect of the present invention, the face member constituting at least part of the face part, the sole member forming at least part of the sole part, the opening on the face side to which the face member is fixed, and the A golf club head including a head body provided with at least a sole side opening to which a sole member is fixed, and having a hollow portion therein, the face member, the sole member, and the Each specific gravity ρf, ρs and ρm of the head body satisfies the relationship of the following formula (1), and the sole member has a yield stress smaller than that of the head body.
ρf ≦ ρm <ρs (1)

  According to a second aspect of the present invention, the sole member includes a main portion fitted into the inner peripheral surface of the opening on the sole side, and protrudes from the opening on the sole side on the hollow portion side, and on the sole side. The golf club head according to claim 1, wherein the golf club head is integrally provided with a peripheral portion of the opening and a retaining portion that is overlapped.

  The invention according to claim 3 is the golf club head according to claim 1 or 2, wherein a gap between the opening on the sole side and the sole member is brazed.

  The invention according to claim 4 is the golf club head according to claim 2, wherein a thickness tp of the peripheral edge portion of the opening on the sole side is equal to or greater than a thickness ts of the main portion of the sole member. .

  According to a fifth aspect of the present invention, there is provided a face portion having a face for hitting a ball, a crown portion connected to the upper edge of the face and forming the upper surface of the head, and a sole portion connecting to the lower edge of the face and forming the head bottom surface. A golf club head having a side portion extending between the crown portion and the sole portion, extending from the toe side edge of the face through the back face to the heel side edge, and having a hollow portion therein A head body provided with at least a crown-side opening provided in the crown portion and a sole-side opening provided in the sole portion, the sole side A main part fitted into the opening of the main part, and a convex part protruding in the thickness direction from the periphery of the main part on one surface of the main part, and having a greater specific gravity than the head body A step of preparing a sole member made of a metal material having a low yield stress, a step of arranging the sole member in an opening on the sole side of the head body with the convex portion facing the hollow portion, and opening on the crown side A caulking step in which the convex portion of the sole member is crushed from the hollow portion side by a pressing tool inserted through the portion, and the convex portion is plastically deformed so as to overlap with a peripheral edge portion of the opening portion on the sole side; And a step of fixing a crown member to the opening on the crown side after the caulking step.

  The invention according to claim 6 is the method for manufacturing a golf club head according to claim 5, further comprising a brazing step of brazing a gap between the main portion and the opening on the sole side after the caulking step. is there.

  According to a seventh aspect of the present invention, in the step of preparing the head body, a primary molded product of the head body in which the opening on the crown side is not provided or a temporary opening smaller than the opening is provided is cast. 7. The method of manufacturing a golf club head according to claim 5, further comprising a step of forming the opening on the crown side in the primary molded product by laser processing.

  In the first aspect of the present invention, the sole member has a specific gravity greater than that of the face member and the head body. For this reason, the center of gravity of the head can be lowered. Further, since the face member has a specific gravity equal to or smaller than that of the head main body, the center of gravity of the head can be located deeper. Further, since the sole member has a yield stress smaller than that of the head main body, it can be plastically deformed with a stress smaller than that of the head main body and can be easily attached to the opening on the sole side by caulking or the like.

  In the invention according to claim 5, the head body is provided with an opening on the crown side, and the projection provided in advance on the sole member by the pressing tool inserted through the opening on the crown side. It includes a caulking step of crushing from the hollow part side of the head and plastically deforming the convex part so as to overlap the peripheral part of the opening part on the sole side. For this reason, when the sole member is caulked and fixed to the opening, the crown or the like is not damaged.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
1 is a perspective view of a golf club head (hereinafter, simply referred to as “head” or “club head”) 1 according to the present embodiment in a reference state, FIG. 2 is a plan view thereof, and FIG. 3 is a bottom view thereof. FIG. 4 shows an enlarged sectional view taken along line XX in FIG.

  The club head 1 of the present embodiment includes a face portion 3 having a face 2 which is a surface for hitting a ball, a crown portion 4 extending from the upper edge 2a of the face 2 to the back face BF side, and forming a head upper surface. A sole portion 5 that is continuous with the lower edge 2b of the face 2 and extends toward the back face BF to form the bottom surface of the head, and a connection between the crown portion 4 and the sole portion 5 and from a toe side edge 2c of the face 2 A side portion 6 that passes through the back face BF and extends to the heel side edge 2d, and a hosel portion 7 that is provided on the heel side of the crown portion 4 and has a shaft insertion hole 7a to which one end of a shaft (not shown) is attached. Have.

  As shown in FIG. 4, the club head 1 has a hollow structure in which a hollow portion i is provided, and is preferably a wood type such as a driver (# 1) or a fairway wood.

  As shown in FIG. 2, the reference state of the club head 1 is that the axial center line CL of the shaft insertion hole 7a is inclined at the lie angle with respect to the horizontal plane HP in an arbitrary vertical plane VP, and the face 2 is tilted with respect to the vertical plane VP by its loft angle (“real loft angle”, the same shall apply hereinafter) to bring the head 1 into contact with the horizontal plane HP. In the present specification, unless otherwise specified, the head 1 is described as being in a reference state.

  Further, as shown in FIG. 2, the head front-rear direction is a direction parallel to a straight line obtained by projecting a normal line N raised from the head center of gravity G to the face 2 onto the horizontal plane HP, and from a certain arbitrary position. Relatively, the face 2 side is the front (or front side), and the back face BF side is the rear (or rear side). The intersection SS between the normal N and the face 2 is defined as a sweet spot.

The club head 1 is preferably 350 cm ³ or more, more preferably it is desirable to have a 380 cm ³ or more by volume. Such a large volume is useful for deepening the moment of inertia and the center of gravity of the head 1. On the other hand, it is too the volume of the club head 1 is large, the increase in head weight, because of a problem such as deterioration and golf rule violation swing balance, preferably 460 cm ³ or less.

  The total weight of the club head 1 can be arbitrarily determined, but is preferably 180 g or more and 210 g or less. If the total weight of the club head 1 is too small, the weight of the head becomes difficult to be felt during the swing, so that the timing is difficult to take and the resilience performance tends to be lowered. On the contrary, if the total weight of the head becomes too large, the club cannot be completely shaken, and the flight distance and directionality of the hit ball tend to deteriorate.

  4 and 5, the club head 1 includes a head body 1A, a face member 1B constituting at least part of the face part 3, and a sole forming at least part of the sole part 5. A member 1 </ b> C and a crown member 1 </ b> D that forms a part of the crown portion 4 are configured. In FIG. 4, the head body 1A is colored for easy understanding.

  In the present embodiment, the four members 1A to 1D are preferably formed of different metal materials. This is particularly preferable in that a metal material having physical properties suitable for the performance required for each opening can be used at the position of each opening.

  As shown in FIGS. 4 and 5, the head body 1A includes a face-side opening Of that opens on the face 3 side, a sole-side opening Os that opens on the sole 4 side, and the crown. A crown-side opening Oc that opens on the part 4 side, a face edge 3A provided around the face-side opening in the face part 3, and a crown-side part 4 provided around the crown-side opening Oc. 4A, the sole edge 5A provided around the opening Os on the sole side in the sole part 5, the side part 6, and the hosel part 7.

  The openings Of, Os, and Oc are provided independently without being connected to each other. Each of the openings Of, Os, and Oc is closed by a face member 1B, a sole member 1C, and a crown member 1D fixed to the head main body 1A, whereby the club head 1 is made.

  In the present embodiment, the face-side opening Of, the sole-side opening Os, and the crown-side opening Oc are all contained in the face 3, the sole 5, and the crown 4. However, it goes without saying that any of the openings Of, Os, and Oc may be provided so as to protrude from the respective portions, and the contour shape thereof can be arbitrarily determined.

  The head main body 1A is preferably formed from, for example, one cast product (more specifically, a lost wax precision cast product) in which the respective parts are integrally formed in advance. Thereby, the productivity of the head 1 is improved. However, the head main body 1A may be made by forging or bending a rolled material, or may be made by joining two or more members.

  The face member 1B has a plate shape in the present embodiment, and is joined to the face-side opening Of by, for example, welding. Although various methods can be employed for the welding, laser welding that has very little thermal influence on the periphery of the welded portion is suitable. The face member 3 preferably includes at least the sweet spot SS, and more preferably occupies 60% or more, more preferably 70% or more of the area of the face 2. In the present embodiment, the face member 3 is formed by the face member 1B and the face edge portion 3A.

  The thickness tf of the face portion 3 is not particularly limited, but is preferably 2.0 mm or more, more preferably 2.5 mm or more, and further preferably 3.0 mm in order to ensure sufficient durability to withstand repeated hitting. The above is desirable. On the other hand, when the thickness tf of the face portion 3 is increased, the weight on the face side is increased and the center of gravity of the head tends to be shallow. Also, the moment of inertia tends to be small. From such a viewpoint, the thickness tf is preferably 4.0 mm or less, more preferably 3.5 mm or less, and still more preferably 3.3 mm or less. In the present embodiment, the thickness tf of the face portion 3 is shown to be substantially constant, but can be variously changed, for example, by reducing the thickness on the peripheral side.

  In this embodiment, the crown member 1D is formed in a plate shape having a smooth three-dimensional shape that is convex toward the outer surface of the head. In order to obtain a larger weight margin on the head upper side and to provide the head center of gravity G at a lower position, it is desirable to reduce the thickness tc of the crown member 1D as much as possible. From such a viewpoint, the thickness tc of the crown member 1D is preferably 1.0 mm or less, more preferably 0.75 mm or less, and further preferably 0.60 mm or less. On the other hand, if the thickness tc of the crown member 1D is too small, the durability of the crown portion 4 may be deteriorated. Therefore, it is preferably 0.30 mm or more, more preferably 0.35 mm or more.

  The manufacturing method of such a thin crown member 1D is not particularly limited. Therefore, any of a rolled material, a cast product, or a forged product may be used. However, in order to reduce the stress concentration, it is desirable that the thickness of the crown member 1D is substantially constant. On the other hand, cast products are likely to contain structural defects and pinholes due to shrinkage cavities and the like, and there are many difficulties in making parts of uniform thickness. Forged products also tend to have thickness variations. From such a viewpoint, a rolled material is most desirable in order to achieve both the small thickness and strength of the crown member 1D.

  The crown member 1D is joined to the crown-side opening Oc of the head body 1A by welding. In particular, laser welding is desirable to fix such a thin crown member 1D to the head body 1A (described later).

  The sole member 1C has a plate shape in the present embodiment, and is fixed to the opening Os on the sole side of the head main body 1A by caulking. Here, “caulking” means that both members are joined by plastic deformation of one or both of the two members to be joined, using frictional force and / or mechanical engagement between the two members. This refers to the process of fixing together. Such caulking is preferable in that both members can be joined even if the head body 1A is a metal that cannot be welded.

In the club head 1 of this embodiment, the specific gravity ρf of the face member 1B, the specific gravity ρs of the sole member 1C, and the specific gravity ρm of the head body 1A satisfy the relationship of the following formula (1). Further, it is desirable that the specific gravity ρc of the crown member 1D and the specific gravity ρs of the sole member 1C satisfy the relationship of the following formula (2).
ρf ≦ ρm <ρs (1)
ρc <ρs (2)

  In this way, by using the material having the largest specific gravity for the sole member 1C arranged on the bottom surface side of the head, the head center of gravity G can be provided at a lower position. The flight distance can be increased. Specifically, since the height of the sweet spot SS is lowered, it is easy to hit the ball above the sweet spot SS. As a result, the back spin amount of the ball is reduced and the launch angle is increased by the vertical gear effect. Thereby, an ideal parabolic trajectory that does not blow up is obtained, and the flight distance increases.

  Further, by reducing the specific gravity of the face member 1B, the head main body 1A, and the crown member 1D, a large weight margin can be twisted out from the face portion 3, the crown portion 4, and / or the side portion 6. These weights are further arranged on the sole portion or the like, so that the center of gravity can be further lowered. Further, since the face member 1B has a specific gravity equal to or smaller than that of the head main body 1A, the head center of gravity can be located deeper. In particular, ρf <ρm is desirable. If ρf> ρm, the center of gravity of the head becomes shallow, which is not preferable.

  In addition, since the sole member 1C is disposed in the opening portion Os that penetrates the head through the inside and outside, a larger material of the sole portion 5 can be replaced with the sole member 1C having a large specific gravity. Therefore, the lowering of the center of gravity is promoted more effectively.

  Here, the specific value ρs of the sole member 1C is not particularly limited as long as it is larger than that of other members. However, in order to further promote the lowering of the center of gravity of the club head, it is preferably 6.0 or more. Preferably it is 6.5 or more, more preferably 7.0 or more. On the other hand, if the specific gravity ρs is too large, the head weight may be excessively increased and the swing balance may be impaired. For this reason, the specific gravity ρs is preferably 10.0 or less.

  Further, the specific gravity ρf of the face member 1B is not particularly limited, but if it is too large, the head gravity center G tends to the face side, and the gravity center depth may be reduced. On the other hand, if the specific gravity ρf of the face member 1B is too small, the material strength tends to be lowered, and the durability of the head may be deteriorated. From such a viewpoint, the specific gravity ρf of the face member 1B is preferably 4.30 to 4.50.

  Further, the specific gravity ρm of the head body 1A is not particularly limited. However, since the head body 1A is the largest component in the club head 1, if the specific gravity ρm is too large, the head weight increases and it is difficult to increase the head volume. On the other hand, if the specific gravity ρm of the head main body 1A is too small, the material strength is liable to decrease, and the durability of the head may be deteriorated. From such a viewpoint, the specific gravity ρm of the head main body 1A is preferably 4.40 to 4.55.

  Further, the specific gravity ρc of the metal material constituting the crown member 1D is not particularly limited, but is preferably 4.0 or more, more preferably 4.4 or more, in order to reduce the weight of the upper portion of the head. Is preferably 5.0 or less, more preferably 4.8 or less.

  The ratio of each specific gravity is not particularly limited. For example, the ratio (ρs / ρm) between the specific gravity ρs of the sole member 1C and the specific gravity ρm of the head body 1A is preferably 1.50 or more, more preferably 1.75. The above is desirable, and the upper limit is preferably 2.25 or less, more preferably 2.10 or less. When the ratio (ρs / ρm) is less than 1.50, if an attempt is made to distribute more weight to the sole side, the thickness of the sole member 1C increases, and the weight is also distributed to the inside of the head, thereby reducing the center of gravity. Tend to be less effective. On the other hand, when the ratio (ρs / ρm) exceeds 2.25, for example, when the specific gravity of the sole member 1C is large, workability may be deteriorated and caulking or the like may be difficult.

  Further, the ratio (ρs / ρf) between the specific gravity ρs of the sole member 1C and the specific gravity ρf of the face member 1B is preferably 1.47 or more, more preferably 1.55 or more, and the upper limit is preferably 2.30 or less, more preferably 2.15 or less is desirable. When the ratio (ρs / ρm) is less than 1.47, the effect of lowering the center of gravity tends to be small as described above. On the other hand, when the ratio (ρs / ρf) exceeds 2.30, the specific gravity of the sole member 1C is excessively increased and the workability tends to be deteriorated.

  The ratio (ρm / ρf) between the specific gravity ρm of the head body 1A and the specific gravity ρf of the face member 1B is preferably 1.00 or more, more preferably 1.01 or more, and the upper limit is preferably 1.05 or less, more preferably 1.03 or less is desirable. When the ratio (ρm / ρf) is less than 1.00, the center of gravity of the head becomes shallow, and the directionality of the hit ball tends to deteriorate. Moreover, when the physical properties of currently known materials are taken into consideration, those having the ratio (ρm / ρf) exceeding 1.05 tend not to be suitable for practical use.

  Further, the joining by the caulking between the sole member 1C and the head main body 1A can be performed by various methods. Preferably, as shown in FIG. 6 which is a partially enlarged view of FIG. 4, the sole member 1C includes a main portion 8 fitted into the inner peripheral surface 12 of the opening portion Os on the sole side, and the main portion 8 on the hollow portion i side. It is desirable to integrally include a retaining portion 9 that protrudes from the sole-side opening Os and overlaps with the peripheral edge 10 of the sole-side opening Os.

  The main portion 8 is preferably fitted in a so-called press-fit state on the inner peripheral surface 12 of the opening Os on the sole side. The press-fitted state is a state in which the outer peripheral surface 8e of the main portion 8 is subjected to compressive stress from the inner peripheral surface 12 of the sole-side opening Os. In addition, after caulking, a gap between the main portion 8 and the opening Os on the sole side may be filled with an adhesive or a hard solder. As a result, the joint between the two becomes more reliable, and the appearance of the club head 1 is improved by filling the gap. In this embodiment, the gap is substantially filled with hard solder (this will be described later).

  In the present embodiment, the main portion 8 includes a front side portion 8a that forms the front side thereof, and a rear side portion 8b that is provided on the rear side and has a thickness ts2 that is greater than the thickness ts1 of the front side portion 8a. Since the main portion 8 can position the center of gravity behind the intermediate position of the length in the front-rear direction of the head, a deeper head center of gravity G can be provided. Further, it is desirable that the front side portion 8a and the rear side portion 8b are connected by an inclined portion 8c whose thickness changes smoothly. As a result, a significant rigidity step is prevented from being formed at the boundary portion between the front side portion 8a and the rear side portion 8b, and stress concentration on the portion is effectively prevented.

  In the present embodiment, the thickness of the main portion 8 changes substantially in two steps from ts1 to ts2, but this may be changed in three steps or more, and continuously. Can also change. In these aspects, since the amount of deformation of the thickness per unit length of the main portion 8 can be made smaller, a rigid step is less likely to occur, which is more advantageous in terms of durability.

  The retaining portion 9 is bent from the main portion 8 so as to fall into the peripheral portion 10 of the opening Os on the sole side due to plastic deformation, and closely overlaps the inner surface of the peripheral portion 10. In addition, it is sufficient that the retaining portion 9 is provided in at least a part of the opening Os on the sole side, but it is preferable that the retaining portion 9 is provided in a substantially annular shape along the opening Os. Here, “substantially annular” means that the retaining portion 9 is completely continuous around the opening Os, and the total length along the opening Os of the retaining portion 9 is the sole-side opening Os. At least 70% or more. Furthermore, the protruding length E from the inner peripheral surface 12 of the opening Os on the sole side of the retaining portion 9 is preferably 2.0 mm or more, more preferably 2.5 mm or more.

  In the above-described joining, the sole member 1C is separated from the friction force between the main portion 8 and the inner peripheral surface 12 of the sole-side opening Os and the sole-side opening Os on the hollow portion i side of the head 1. Due to the synergistic effect of the protrusion and the engagement by the retaining portion 9 that overlaps the peripheral edge portion 10 of the opening Os on the sole side, a very high coupling strength can be obtained in the head longitudinal direction and the vertical direction. Accordingly, it is possible to effectively prevent the sole member 1C from falling off the head main body 1A.

  In order to realize such joining by caulking, a material having a yield stress smaller than that of the head body is used for the sole member 1C. For this reason, the above-mentioned joining state can be easily obtained by plastically deforming the sole member 1C while suppressing plastic deformation or the like of the head main body 1A to a minimum (or none). This suppresses damage to the head main body 1A, and can prevent rework and increase in defective products. This contributes to improvement in productivity of the club head 1.

  Here, the specific value of the yield stress σs of the sole member 1C is not particularly limited, but if it is too small, the durability of the sole portion 5 tends to be lowered when the club head is used, and conversely, if it is too large, the joining work by caulking Tend to make it difficult. From such a viewpoint, the yield stress σs of the sole member 1C is preferably 260 MPa or more, more preferably 300 MPa or more, further preferably 350 MPa or more, and the upper limit is preferably 700 MPa or less, more preferably 650 MPa or less. More preferably, it is 600 MPa or less.

Here, the “yield stress” is a so-called 0.2% proof stress, and is specifically determined according to “Metal material tensile test piece” of JIS Z2201 and “Metal material tensile test method” of Z2241. Specifically, first, a tensile test was performed using the No. 13B test piece described in JIS Z2201, and the crosshead speed was 1.0 mm / min, and a relationship line between the load and the amount (%) of the test piece extended. Ask for a figure. And the proof stress σ _0.2 when the permanent elongation is 0.2% is the same as that of JIS Z2241. (4) Obtained by the offset method defined in (a).

  Further, the value of the yield stress σm of the head main body 1A is not particularly limited, but if it is too small, the durability of the entire head tends to be lowered when the club head is used. From such a viewpoint, the yield stress σm is preferably 700 MPa or more, more preferably 750 MPa or more. On the other hand, if the yield stress σm of the head main body 1A is too large, casting becomes difficult, and cracks or the like are likely to occur during bending or drawing, so 1000 MPa or less, more preferably 950 MPa or less is desirable.

  The ratio (σm / σs) between the yield stress σm of the head body 1 and the yield stress σs of the sole member 1C is preferably 1.20 or more, more preferably 1.40 or more. When the ratio (σm / σs) is less than 1.20, both yield stresses approach each other, so that the head main body 1A is likely to be plastically deformed when the sole member 1C is plastically deformed. This is not preferable because it causes a decrease in bonding strength and damage to the head body. On the other hand, if the ratio (σm / σs) is too large, for example, σs becomes too small, and the sole member 1C may be deformed by an external force or an impact during play. From such a viewpoint, the ratio (σm / σs) is preferably 3.30 or less, more preferably 3.00 or less.

  Further, the face member 1B needs to have sufficient durability so as not to be damaged even when the ball is repeatedly hit. From such a viewpoint, the yield stress σf of the metal material used for the face member 1B is preferably 1000 MPa or more, more preferably 1100 MPa or more. On the other hand, if the yield stress of the face member 1B is too large, the plastic workability may deteriorate. In addition, since a material having a large yield stress tends to have a high specific gravity, when the face member 1B is formed with a predetermined thickness, the weight on the face side increases and the degree of freedom in designing the center of gravity tends to deteriorate. Therefore, it is preferably 1300 MPa or less, more preferably 1250 MPa or less.

  The ratio (σf / σm) between the yield stress σf of the face member 1B and the yield stress σm of the head body 1A is preferably 1.00 or more, more preferably 1.10 or more, and the upper limit is set. , Preferably 1.75 or less, more preferably 1.65 or less. When the ratio (σf / σm) is less than 1.00, the durability of the face portion 3 is likely to decrease. Conversely, when the ratio (σf / σm) exceeds 1.75, the durability of the head body 1A is low. There is a tendency to decrease.

  Further, the ratio (σf / σs) between the yield stress σf of the face member 1B and the yield stress σs of the sole member 1C is preferably 1.15 or more, more preferably 1.50 or more, and the upper limit is set. , Preferably 4.30 or less, more preferably 3.50 or less. When the ratio (σf / σs) is less than 1.15, the durability of the face portion 3 is likely to deteriorate. Conversely, when the ratio (σf / σs) exceeds 4.30, the strength of the sole member 1C is relatively high. Therefore, the sole member 1C is likely to be deformed or damaged.

  As a metal material suitable for the sole member 1C satisfying the above-described yield stress σs and specific gravity ρs, preferably stainless steel, especially SUS630 (yield stress: 800 MPa, specific gravity: 7.80), SUS255 (yield stress: 550 MPa, specific gravity). SUS431 (yield stress: 410 MPa, specific gravity: 7.73) or SUS304 (yield stress: 300 MPa, specific gravity: 7.93).

  In addition to stainless steel, for example, a Mn-based damping alloy having a large specific gravity and excellent damping properties is desirable. Such an alloy absorbs the vibration of the sole portion 5 at the time of hitting the ball and is useful for giving the golfer a soft feel with little vibration.

  The Mn-based damping alloy contains the most Mn (manganese) among the alloy constituent elements and can exhibit damping characteristics. Such a damping alloy is easily twinned when a load is applied from the outside. Twins can be easily moved, their width increases with increasing load, and new twins are generated elsewhere. Due to the generation and movement of twins in such a Mn-based damping alloy, the kinetic energy is changed to thermal energy, and vibration is absorbed. The twins disappear when the load is removed, and the Mn-based damping alloy can return to an unloaded state.

As the damping characteristic, for example, the logarithmic attenuation rate (δ) is desirably 0.21 or more. This is because if the logarithmic attenuation factor is less than 0.21, a practical vibration damping effect cannot be obtained. Particularly preferably, the logarithmic decay rate is 0.25 or more, more preferably 0.35 or more, and the upper limit is not particularly restricted, but from the viewpoint of material availability, cost, etc. It can be determined as 90 or less, and further 0.70 or less. In the present specification, the logarithmic decay rate is a value measured by a central excitation method using a thin plate sample having a thickness of 1 mm, a width of 10 mm, and a length of 160 mm, and the measurement condition is that the amplitude distortion is 5 × 10 at room temperature. ^-4 .

  The Mn-based damping alloy preferably includes, for example, Cu: 17 to 27 wt%, Ni: 2 to 8 wt%, Fe: 1 to 3 wt%, with the balance being Mn and inevitable impurities. Such an alloy is preferable in that it has high vibration damping action, plastic deformation ease and high strength. Further, the alloy having the above composition can be easily cut, cast, hot-worked, cold-worked, welded and pressed, and thus is preferable in that it has excellent workability as the sole member 1C. However, it goes without saying that alloys of other compositions can be adopted as long as they are Mn-based damping alloys that can exhibit a vibration damping action. For example, an Fe—Al alloy (for example, Fe-7.5 to 8.5Al), a Ni—Ti alloy, an Al—Zn alloy, or the like can also be employed.

  Further, as the metal material constituting the head body 1A, for example, pure titanium (yield stress: 500 MPa, specific gravity: 4.51) or a titanium alloy is suitable. In particular, as titanium alloys, Ti-6Al-4V (yield stress: 900 MPa, specific gravity: 4.42), Ti-Fe-O (for example, “KS100” manufactured by Kobe Steel, Ltd., yield stress: 600 MPa, specific gravity: 4.51) or Ti—Fe—O—Si (for example, “KS120SI” manufactured by Kobe Titanium Co., Ltd., yield stress: 750 MPa, specific gravity: 4.51) is preferable.

  The metal material constituting the face member 1B is preferably a titanium alloy, particularly Ti-5.5Al-1Fe (yield stress: 1000 MPa, specific gravity: 4.38) or Ti-6Al-4V (yield stress: 900 MPa). , Specific gravity: 4.42) and the like are desirable. In addition, various things, such as a forging material, a casting material, or a rolling material, are employable as a titanium alloy.

  Further, as the metal material constituting the crown member 1D, a titanium alloy is desirable, and Ti-15V-3Cr-3Al-3Sn (yield stress: 1200 MPa, specific gravity 4.76) is particularly preferable.

  A method for manufacturing the club head 1 configured as described above will be described. In the present embodiment, first, a step of preparing the head main body 1A, the sole member 1C, the face member 1B, and the crown member 1D is performed.

  As shown in FIG. 5, the head main body 1 </ b> A of the present embodiment is provided with a crown-side opening Oc, a sole-side opening Os, and a face-side opening Of.

  As shown in FIG. 5, the sole member 1 </ b> C includes the main portion 8 that can be fitted into the opening Os on the sole side of the head body 1 </ b> A, and one main surface (upper surface in FIG. 5) of the main portion 8. It is prepared as what has the convex part 13 which protrudes in the thickness direction from the periphery of the part 8. FIG. Further, in this embodiment, the convex portion 13 is continuously provided in an annular shape around the main portion 8. Further, as shown in FIG. 7, the convex portion 13 has an outer peripheral surface 13 a that rises substantially vertically upwards flush with the main portion 8, while an inner peripheral surface 13 b of the convex portion 13 is It consists of the inclined surface which inclines to the outer peripheral surface 13a side. Thereby, the convex part 13 makes a cross-sectional substantially taper shape.

  Next, as shown in FIG. 7A, the sole member 1C is disposed in the sole-side opening Os of the head body 1A so that the convex portion 13 faces the hollow portion i of the head 1. Is done. In this embodiment, the main portion 8 is formed to be slightly smaller than the opening portion Os on the sole side, and therefore can be fitted into the opening portion Os as shown in FIG. Further, as shown in FIG. 7A, the head main body 1A in which the sole member 1C is fitted is supported by the lower mold M1 on the outer surface of the sole portion.

  Next, as shown in FIG. 7B, the convex portion 13 of the sole member 1C is hollowed out by the pressing tool M2 inserted from the top of the head through the opening Oc (not shown) on the crown side. By crushing from the part i side, the convex part 13 is plastically deformed so as to overlap the peripheral part 10 of the opening part Os on the sole side, and a caulking step for forming the retaining part 9 is performed.

  In the present embodiment, the pressing tool M2 has a substantially flat pressing surface, but the convex portion 13 has a tapered shape inclined toward the outer peripheral surface 13a side as described above. For this reason, by pressing the convex portion 13 almost vertically from the top with the pressing tool M2, the convex portion 13 can be easily plastically deformed so as to fall down in the direction of protruding from the opening Os. Thereby, the retaining portion 9 can be reliably formed. In order to promote such deformation of the convex portion 13, it is also preferable to provide a slit 25 in the convex portion 13 as shown in FIG. 5.

  Further, when the convex portion 13 is pressed, a compressive force acts on the peripheral portion of the main portion 8. As a result, the main portion 8 is expanded in diameter and is closely press-fitted into the inner peripheral surface 12 of the opening Os on the sole side.

  In order to perform such caulking more smoothly, as shown in FIG. 2, it is provided so that the opening Os on the sole side fits in the opening contour projected from the opening Oc on the crown side on the sole 5. It is desirable that

  Here, as shown in FIG. 6, in the head main body 1A, if the thickness tp of the peripheral edge portion 10 of the opening Os on the sole side is too small, the peripheral edge portion 10 may be greatly deformed by stress during caulking. is there. For this reason, the thickness tp of the peripheral edge portion 10 is preferably 1.5 mm or more, more preferably 2.0 mm or more. On the other hand, in order to give a larger weight to the sole member 1C, the thickness tp of the peripheral edge portion 10 is preferably suppressed to 3.0 mm or less. In the present embodiment, it is desirable that the peripheral edge portion 10 has a width that is at least the protruding length E of the retaining portion 9.

  Further, the maximum thickness ts of the main portion 8 of the sole member 1C is not particularly limited, but if it is too small, a sufficient weight cannot be given to the sole member 1C. From such a viewpoint, the thickness ts is preferably 0.8 mm or more. On the other hand, even if the thickness ts is too large, the head weight tends to be excessively increased. Therefore, the thickness is preferably 4.0 mm or less, more preferably 3.0 mm or less, and further preferably 2.0 mm or less.

  Note that the thickness tp of the peripheral edge 10 is preferably equal to or greater than the thickness ts of the main portion 8 of the sole member 1C. That is, the ratio (tp / ts) between the thicknesses tp and ts is preferably 1.0 or more, more preferably 1.5 or more, and still more preferably 1.6 or more. Thereby, damage to the peripheral edge 10 of the opening Os on the sole side during caulking can be maintained. From the viewpoint of reducing the weight of the head main body 1A, the ratio (tp / ts) is preferably 2.5 or less, more preferably 2.0 or less.

  In the manufacturing method of the present embodiment, the sole member 1C is sandwiched between the pressing tool M2 inserted into the hollow portion i from the opening Oc on the crown side and the lower mold M1 located on the outer surface side of the sole portion 5. Can be transformed. For this reason, since the load during caulking does not act on the crown portion 4 at all, damage to the head main body 1A is more reliably reduced. On the other hand, in the thing of the said patent document 1, when pressing a sole plate into a recessed part, since the pushing force from a sole part side must be received by the crown part of the head main body distribute | arranged in the metal mold | die. The crown part is deformed during the press-fitting, or the crown part must be thickened to prevent this.

  In the present embodiment, after the caulking step, a brazing step of brazing the gap between the main portion 8 and the opening Os on the sole side is performed. Sufficient bonding strength can be obtained by the caulking. However, a small gap may remain between the sole-side opening Os and the sole member 1C. If the gap is left as it is, foreign matter may enter the hollow portion i of the head 1 from there, and it is preferable that the gap is brazed from the head outer surface side.

  Here, brazing is a kind of brazing, and melts a filler material having a melting point lower than that of the base material (so-called “hard brazing”) without melting the base material, and then capillaries. This means that bonding is performed by spreading this in the gap between the bonding surfaces using the phenomenon. In order to firmly fix the brazing material in the gap, prior to the caulking step, the head body 1A and the sole member 1C are pre-treated in advance to remove rust, oxides, oils and dirt on the surface.

  After the caulking step, for example, the head main body 1A is held upside down, and a paste-like or powdery brazing material is stacked along the boundary portion between the sole member 1C and the sole-side opening Os. The head body 1A on which the brazing material is stacked is heated in a furnace. As a result, only the brazing material is melted and flows into the gap between the sole-side opening Os and the sole member 1C. Then, the brazing material can be cured in the gap by taking out the head body 1A from the furnace and cooling it.

  Here, since the titanium alloy is a highly active metal, brazing is preferably performed in an atmosphere of an inert gas or vacuum. Further, as the furnace, a high-frequency induction brazing furnace or the like that can locally heat only the brazing part and minimize the influence of heat on other parts is particularly desirable.

  The brazing material is not particularly limited, but when brazing a titanium alloy and stainless steel as in the present embodiment, silver brazing, aluminum brazing, or titanium brazing can be employed. However, since the aluminum solder has a slightly lower melting point, for example, the brazing material may be dissolved again by frictional heat such as a polishing process at the time of head finishing. In addition, titanium brazing has a drawback that workability is somewhat poor. From this point of view, silver brazing is particularly desirable for the brazing material.

  The silver solder is not particularly limited, but preferably Ag-15Cu, Ag-7.5Cu-0.2Li, Ag-20Cu-2Ni-0.4Li, Ag-28Cu-0.2Li, Ag-22Cu-17Zn. -5Sn, Ag-3Li, Ag-27Cu-5Ti, and the like are preferable.

  In order to further increase the bonding strength by brazing, it is particularly desirable to include a step of cleaning the brazed surface using a flux. As such flux, borides such as borax, boric acid, boron, fluoride or chloride are used. Prior to the placement of the brazing material, the flux is preliminarily deposited on the brazing portion, and by heating the flux, the flux can flow into the gap between the sole-side opening Os and the sole member 1C to clean the brazing surface. Thereafter, a brazing material can be put on the brazing portion cleaned with the flux and heated. Further, the flux can be placed in the brazing portion together with the brazing material, and can be dissolved together with the brazing material.

  Next, after the sole member 1C is joined to the head main body 1A, a step of fixing the face member 1B and the crown member 1D to the head main body 1A is performed. In this embodiment, these are joined by laser welding. Laser welding can supply very high density energy to a very small area, so that it can be welded in a shorter time than other welding methods. In particular, even a very thin small crown member 1D having a thickness tc of 0.6 mm or less can be welded to the head main body 1A with minimal thermal influence on the periphery of the joint, such as tissue transformation or thermal deformation. This is preferable.

  For the laser welding, for example, a carbon dioxide laser using carbon dioxide or a YAG (yttrium, aluminum, garnet) laser is suitable. In particular, a YAG laser is preferable because a laser with high output and high density energy density can be easily obtained.

  Further, in order to perform such laser welding with high accuracy, the head main body 1A is made to have an opening on the crown side, as shown in FIG. 8 and FIG. It can also be prepared by casting as a primary molded product 1Am of the head body not provided with Oc, and precisely forming the crown-side opening Oc by laser processing in the crown.

  The primary molded product 1Am is not provided with the opening Oc on the crown side. However, the positioning guide member 15 for positioning the crown member 1D and the finish of the crown portion surrounded by the guide member 15 are provided. A receiving portion 4b having an outer surface substantially recessed from the surface 4a by the thickness tc of the crown member 1D is provided. Other structures are substantially the same.

  The guide member 15 is a ridge protruding at a small height from the finished surface 4a. In this embodiment, the guide member 15 continuously extends along the contour line of the outer peripheral edge of the crown member 1D. Therefore, the guide member 15 is useful for positioning the crown member 1D on the head body 1A. Since the guide member 15 is later removed by machining such as polishing, the height is preferably about 0.5 to 1.0 mm.

  Further, in the laser processing, as shown in FIG. 9A, the laser beam LB is sequentially irradiated along a position separating a predetermined distance RW from the guide member 15 inward. As a result, as shown in FIG. 9B, the receiving portion 4b is pierced leaving only the receiving piece 16 having a small width RW. As a result, an opening Oc on the crown side and a receiving piece 16 having a width RW surrounding the periphery are formed. The width RW of the receiving piece 16 is preferably 1 mm or less, particularly about 0.3 to 0.8 mm in order to reduce the weight at the crown portion. The receiving piece 16 having such a very small width RW cannot obtain an accurate shape by casting due to the problem of molten metal flow, but by performing laser processing (cutting) after casting as in this embodiment, The narrow receiving portion 10b can be formed with high accuracy together with the opening Oc on the crown side.

  In the above-described embodiment, the primary molded product 1Am of the head main body is not provided with any opening at the crown, but, for example, as shown by the phantom line in FIG. May be provided with a small temporary opening Om. This aspect is preferable in that less material is discarded when the opening Oc is pierced.

  Thereafter, as shown in FIG. 10A, the crown member 1D is fitted into the region surrounded by the guide member 15 of the head main body 1A, and the inner surface and the peripheral portion of the crown member 1D are arranged on the receiving piece 16. Held on.

  Next, as shown in FIG. 10B, a minute gap between the outer peripheral edge of the crown member 1D and the guide member 15 is joined from the outer surface side of the head 1 by laser welding. In this embodiment, a crown member 1D having a small thickness tc is used in order to reduce the weight of the crown portion 4. However, since laser welding can radiate high-density thermal energy at a pinpoint in a very small range. Thus, welding can be performed in a short time, and as a result, the head body 1A can be reliably joined while minimizing thermal effects such as transformation and deformation of the surrounding tissue of the crown member 1D.

  Further, in laser welding, very deep penetration is obtained locally, so that a deep joining bead 19 reaching the receiving piece 16 is obtained as shown in FIG. As a result, higher bonding strength can be obtained while minimizing the surrounding thermal damage.

  11 and 12 show still another embodiment of the present invention. In this embodiment, the face member 1B integrally includes a base 20 that forms a substantially entire area of the face 2 and an extension 21 that extends from at least a part of the edges 2a to 2d of the face 2 to the back face BF side. It is formed in a substantially cup shape. Such a face member 1B is preferable in that it can provide a joint with the head main body 1A on the back face side, and can further improve resilience and durability.

  As described above, the embodiment of the present invention has been described by taking the wood type golf club head as an example. However, the present invention is not limited to such an aspect, and any utility type or It is applied to various golf club heads such as putter type.

Based on the specifications shown in Table 1, wood type driver heads having a head volume of 435 cm ³ and a head weight of 195.0 g were made as prototypes, and various performances were evaluated. In addition, Examples 1, 3 and 4 have the basic shapes shown in FIGS. 1 to 5, and Example 2 has the basic shapes shown in FIGS. Comparative Example 1 was a club head that was based on Example 2 but did not have an opening on the sole side. Comparative Example 2 was based on Examples 1, 3 and 4, but was a club head having no opening on the sole side and no opening on the crown side. In all cases, the thickness tf of the face portion was unified to 3.2 mm.

In each of the heads of the examples, the head main body, the face member, and the crown member were joined by carbon dioxide laser welding. Moreover, after the sole member was caulked with a pressing tool inserted from the opening on the crown side, a brazing process using silver brazing was performed. The head body was provided with an opening on the crown side by laser processing the primary molded product.
The items evaluated are as follows.

<Height of center of gravity>
The center of gravity of the club head was measured by measuring the height of the sweet spot from the horizontal plane.

<Depth of center of gravity>
The depth of the center of gravity represents the depth of the center of gravity of the head. The length x1 of the normal line drawn from the center of gravity of the head to the vertical plane in the reference state and the length in the head longitudinal direction from the vertical plane to the forefront position of the face ( Measured as the sum of (face progression) x2.

<Inertia moment>
The moment of inertia of the head was measured using MOMENT OF INERTIA MEASURING INSTRUMENT MODEL NO.005-002 manufactured by INERTIA DYNAMICS Inc. The left and right moments of inertia are moments of inertia around the vertical axis passing through the center of gravity of the head. The vertical moment of inertia is the moment of inertia about a horizontal axis that passes through the center of gravity of the head and is parallel to the horizontal plane and the vertical plane VP.

<Hit feeling>
Each golf club made 10 trial shots of the same golf ball with 5 golfers, 5 points with good hit feeling (soft with little impact), 1 point with bad hit feeling (impact feels hard and hard) The average value was shown by the 5-point method. The larger the value, the better.

<Durability>
Each head is mounted on a carbon shaft V-25 (hardness: X) made by SRI Sports, and a 45-inch wood-type golf club is prototyped. This is attached to a swing robot made by Miyamae and head speed is 54 m / s. Adjusted and evaluated by a test that hits the golf ball continuously at the sweet spot position. Then, the head was observed with the naked eye every 500 shots, and the number of hits in which the head was damaged was displayed.

<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). The larger the numerical value, the better. However, in order to satisfy the golf rules, it is necessary to be less than 0.830.
Table 1 shows the test results.

  As a result of the test, it was confirmed that the head of the example achieved a low center of gravity without impairing durability.

It is a perspective view of the standard state of the head which shows the embodiment of the present invention. FIG. It is the bottom view. It is XX sectional drawing of FIG. It is a disassembled perspective view of a head. It is the elements on larger scale of FIG. (A), (B) is a fragmentary sectional view explaining a caulking process. It is a perspective view which illustrates the primary molded product of a head main body. (A), (B) is a fragmentary sectional view explaining the process of forming the opening part by the side of a crown. (A)-(C) are the fragmentary sectional views explaining the process of welding a crown member to the opening part by the side of a crown. It is a perspective view of the head which shows other embodiment of this invention. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Golf club head 1A Head main body 1B Face member 1C Sole member 1D Crown member 2 Face 3 Face part 4 Crown part 5 Sole part 6 Side part 7 Neck part 8 Sole member main part 9 Sole member retaining part 13 Convex part Of Face-side opening Os Sole-side opening Oc Crown-side opening M2 Press

Claims (7)

A face member constituting at least a part of the face part,
A sole member that forms at least a part of the sole portion; and a head body provided with at least a face-side opening to which the face member is fixed and a sole-side opening to which the sole member is fixed. And a golf club head provided with a hollow portion therein,
The specific gravity ρf, ρs, and ρm of the face member, the sole member, and the head body satisfy the relationship of the following formula (1),
The golf club head according to claim 1, wherein the sole member has a yield stress smaller than that of the head body.
ρf ≦ ρm <ρs (1)   The sole member includes a main portion fitted into the inner peripheral surface of the opening on the sole side, and a detachment that protrudes from the opening on the sole side on the hollow portion side and overlaps with a peripheral portion of the opening on the sole side. The golf club head according to claim 1, wherein the golf club head is integrally provided with a stopper.   The golf club head according to claim 1, wherein a gap between the sole side opening and the sole member is brazed.   The golf club head according to claim 2, wherein a thickness tp of the peripheral portion of the opening on the sole side is equal to or greater than a thickness ts of the main portion of the sole member. A face portion having a face for hitting a ball;
A crown portion connected to the upper edge of the face and forming the upper surface of the head;
A sole portion that is connected to the lower edge of the face and forms the bottom of the head;
A golf club head having a side portion extending between the crown portion and the sole portion, extending from a toe side edge of the face through a back face to a heel side edge, and having a hollow portion therein A method of manufacturing comprising:
Preparing a head body provided with at least a crown-side opening provided in the crown and a sole-side opening provided in the sole;
A main portion fitted into the opening on the sole side, and a convex portion projecting in the thickness direction from the periphery of the main portion on one surface of the main portion, and having a specific gravity greater than that of the head body; Preparing a sole member made of a metal material having a low yield stress;
Disposing the sole member in an opening on the sole side of the head body with the convex portion facing the hollow portion;
With the pressing tool inserted through the opening on the crown side, the convex portion of the sole member is crushed from the hollow portion side, and the convex portion is plasticized so as to overlap the peripheral edge of the opening on the sole side. A caulking process to deform,
A method of manufacturing a golf club head, comprising a step of fixing a crown member to an opening on the crown side after the caulking step.   The golf club head manufacturing method according to claim 5, further comprising a brazing step of brazing a gap between the main portion and the opening on the sole side after the caulking step. The step of preparing the head main body is a step of molding a primary molded product of the head main body provided with a temporary opening which is not provided with the opening on the crown side or smaller than the opening by casting,
The method of manufacturing a golf club head according to claim 5, further comprising: forming the crown side opening in the primary molded product by laser processing.

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