JP5237688B2 - Golf club head - Google Patents

Description

  The present invention relates to a golf club head that can increase the degree of freedom in weight distribution design.

  In recent years, various golf club heads with a large head volume have been proposed along with improvements in manufacturing technology. Such a large club head has an advantage that the directionality of the hit ball is easy to be stable because a large sweet area and moment of inertia can be obtained.

  On the other hand, when the head volume is increased, the design freedom of the club head is reduced. That is, considering the swing balance, it is necessary to keep the club head weight below a certain value. Therefore, when the club head is increased in size within a limited weight, a weight margin (such as the weight of the weight member) that can be used to position the center of gravity of the head rearward is reduced.

  In order to eliminate the above drawbacks, it is conceivable to use, for example, a magnesium alloy having a small specific gravity for the face member or the head body. However, magnesium alloys have low strength and tend not to have sufficient durability.

  Related literature includes the following:

JP 2007-84915 A

  The present invention has been devised in view of the above circumstances, and a low specific gravity titanium alloy having a different composition is applied to a face member having a face for hitting a ball and a head body to which the face member is fixed. The main purpose is to provide a golf club head with a high degree of design freedom based on the use of each.

According to a first aspect of the present invention, there is provided a golf club head having a hollow structure including a face member having a face for hitting a ball and a head body having an opening on the front side to which the face member is fixed. The face member is made of a first titanium alloy, and the head body is made of a second titanium alloy having a composition different from that of the first titanium alloy, and the first titanium alloy and the first titanium alloy Each of the specific gravity G1 and G2 of the titanium alloy 2 is 4.35 to 4.38, and the elastic modulus (E1 / G1) per unit specific gravity of the first titanium alloy is 28.54 to 29.68 and The elastic modulus (E2 / G2) per unit specific gravity of the second titanium alloy is 24.14 to 25.17 .

  The invention according to claim 2 is the golf club head according to claim 1, wherein the elastic modulus E1 of the first titanium alloy is larger than the elastic modulus E2 of the second titanium alloy.

  The invention according to claim 3 is the golf club head according to claim 1 or 2, wherein the face member is made of a forged product or a press-formed product, and the head body is made of a cast product.

According to a fourth aspect of the present invention, the specific gravity G1 of the first titanium alloy is 4.37 to 4.38, and the specific gravity G2 of the second titanium alloy is 4.35 to 4.37. Item 4. The golf club head according to any one of Items 1 to 3.

A fifth aspect of the present invention is the golf club head according to any one of the first to fourth aspects , wherein the specific gravity G1 of the first titanium alloy is not less than the specific gravity G2 of the second titanium alloy .

  In the golf club head of the present invention, the face member is formed of a first titanium alloy, and the head body is formed of a second titanium alloy having a composition different from that of the first titanium alloy. Therefore, each of the face member and the head main body can be improved by using a titanium alloy having a composition corresponding to the required characteristics.

  Moreover, each specific gravity of a 1st titanium alloy and a 2nd titanium alloy is less than 4.42. Therefore, the club head of the present invention can reduce the weight of both the face member and the head main body and create a large weight margin for moving the center of gravity of the head. Therefore, according to the present invention, a golf club head having a high degree of freedom in weight distribution design is provided.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view of a golf club head 1 of the present embodiment, and FIG. 2 is an exploded perspective view thereof.

  In the figure, a golf club head (hereinafter sometimes simply referred to as “head” or “club head”) 1 includes a face portion 3 having a face 2 for hitting a ball on the front surface, and an upper edge 2 a of the face 2. The crown portion 4 that is continuous and forms the upper surface of the head, the sole portion 5 that is continuous with the lower edge 2b of the face 2 and forms the bottom surface of the head, and the crown portion 4 and the sole portion 5 are back from the toe side edge 2c of the face 2. A side portion 6 extending to the heel side edge 2d through the face BF and a hosel portion 7 having a shaft insertion hole 7a to which a shaft (not shown) is attached are provided, and in this embodiment, a hollow portion i is provided inside. The wood type is exemplified.

The club head 1 is preferably 400 cm ³ or more, more preferably 425 cm ³ or more, still more preferably has a 450 cm ³ or more by volume. As a result, the moment of inertia of the head 1 is increased, the head blurring during a miss shot is minimized, and the directionality of the hit ball is improved. On the other hand, even if the volume of the club head 1 is too large, the club weight increases, and there is a possibility that, for example, the swing balance is deteriorated, the head speed is reduced, and the durability is reduced due to the thinning of each part of the head. From this point of view, the upper limit of the volume of the head 1 is preferably 470 cm ³ or less, more preferably 460 cm ³ or less. The head volume means the total volume surrounded by the outer surface of the head in a state where the shaft insertion hole 7a of the hosel portion 7 is filled.

  Further, in order not to significantly deteriorate the swing balance, the weight of the club head 1 is preferably 175 g or more, more preferably 180 g or more, further preferably 185 g or more, and preferably 210 g or less, more preferably 205 g or less. desirable.

  As shown in FIG. 2, the club head 1 of the present embodiment is composed of a face member 1A having the face 2 and a head body 1B having an opening O on the front side to which the face member 1A is fixed. .

  The face member 1A of the present embodiment includes a base 8 having the face 2 on the front surface, and a substantially cup integrally including an extension 9 extending from at least a part of each edge 2a to 2d of the face 2 to the rear of the head. It is formed in a shape. The base portion 8 and the extension portion 9 are not joined by welding, but are bent by press bending or forging.

  In the present embodiment, the base portion 8 forms a substantially entire area of the face portion 3. However, it may constitute a part of the face portion 3.

  Further, as shown in FIG. 3, the face portion 3 has, for example, a central portion 3A having a large thickness t1 (maximum thickness in this example) as a relative one, and surrounding the central portion 3A. And a thin-walled portion 3B having a thickness t2 (in this example, the minimum thickness) that extends in a ring shape and is smaller than the central portion 3A.

  The central portion 3A constitutes a face central region including at least the sweet spot SS. The sweet spot SS is a point where a normal N standing on the face 2 from the head center of gravity GH intersects the face 2. Such a face portion 3 sufficiently maintains the durability of the central portion 3A that frequently comes into contact with the ball and bends the thin portion 3B having a small thickness so that the spring effect of the head 1 is within the range of the golf regulations. Can be maximized. The thin portion 3B is useful for reducing the weight of the face portion 3 and increasing the depth of the center of gravity. In this specification, the depth of the center of gravity of the club head is the shaft axis center line CL (this is the shaft insertion hole in the reference state in which the head 1 is placed on the horizontal plane HP with the specified lie angle and loft angle. 7a can be used as a substitute for the horizontal distance L1 from the vertical plane VP to the leading edge Le and the horizontal distance L2 from the vertical plane VP to the head center of gravity GH.

  The thickness t1 of the central portion 3A is preferably 2.90 mm or more, more preferably 2.95 mm or more, still more preferably 3.00 mm or more, and the upper limit is preferably 3.50 mm or less, more preferably 3. 40 mm or less, more preferably 3.3 mm or less is desirable. When the thickness t1 is less than 2.90 mm, the coefficient of restitution of the head 1 tends to exceed the upper limit defined by the golf rules. Conversely, when the thickness t1 exceeds 3.50 mm, the weight of the face portion 3 increases. As a result, the depth of gravity tends to decrease.

  Further, the thickness t2 of the thin portion 3B is preferably 2.35 mm or more, more preferably 2.40 mm or more, and further preferably 2.50 mm or more, and the upper limit is preferably 2.70 mm or less, more preferably 2. 60 mm or less is desirable. When the thickness t2 is less than 2.35 mm, the durability of the face portion 2 is likely to be lowered. Conversely, when the thickness t2 is more than 2.70 mm, the spring effect of the club head 1 is excessively lowered and the flight distance is impaired. Absent.

  Further, the face portion 3 of the present embodiment is provided with a thickness transition portion 3C connecting the portions 3A and 3B by smoothly changing the thickness between the central portion 3A and the thin portion 3B. As a result, the stress concentration at the boundary portion between the central portion 3A and the thin portion 3B is alleviated, which helps to further improve the durability of the face portion 3.

  As shown in FIG. 2, the extension portion 9 of this embodiment includes a crown-side extension portion 9 a that forms the front side portion of the crown portion 4, and a sole-side extension portion 9 b that forms the front side portion of the sole portion 5. A toe-side extension 9c that forms a toe-side front side of the side part 5 and a heel-side extension 9d that forms a heel-side front side of the side part 5; It is formed continuously. However, the heel side of the extension portion 9 may be cut out in a concave shape in accordance with the shaft insertion portion 7.

  The head body 1B includes a crown main portion 4a that constitutes a main portion of the crown portion 4, a sole main portion 5a that constitutes a main portion of the sole portion 5, and a space between the crown main portion 4a and the sole main portion 5a. The side main portion 6a that forms the joint and the main portion of the side portion 6 and the hosel portion 7 are integrally provided, and an opening portion O to which the face member 1A is joined is formed on the front side thereof.

  As shown in FIG. 3, the thickness t3 of the crown main portion 4a, the thickness t4 of the sole main portion 5a, and the thickness t5 of the side main portion 6a are not particularly limited, but are small. If it is too large, the durability of the head main body 1B tends to be lowered. Conversely, if it is too large, the head weight increases, and the degree of freedom in weight distribution design tends to be impaired. From such a viewpoint, the thicknesses t3, t4, and t5 are preferably 0.65 mm or more, more preferably 0.70 mm or more, and the upper limit is preferably 1.2 mm or less, more preferably 1. 1 mm or less is desirable.

  Further, as shown in FIG. 3, a weight member 20 is fixed to the head main body 1B of the present embodiment on the sole main portion 5a and / or the side main portion 6a on the rear side of the head.

  The weight member 20 is made of, for example, a high specific gravity metal material, and is integrated with the head main body 1B by an adhesive or screwing. Such a weight member 20 is useful for increasing the depth of the center of gravity of the head and improving the directionality of the hit ball. The specific gravity of the weight member 20 is not particularly limited as long as it is larger than the specific gravity G2 of the head main body 1B, but is preferably 8.0 or more, more preferably 10.0 or more. The upper limit of specific gravity is not particularly defined, but is preferably 20.0 or less from the viewpoint of material acquisition cost and the like.

  As a specific material of the weight member 20, for example, a copper alloy, a nickel alloy, brass, lead, stainless steel, tungsten, a tungsten alloy, or the like is desirable, and one or more of these can be used in combination.

  Further, as shown in FIG. 3, the club head 1 of the present embodiment is manufactured by welding a face member 1A and a head main body 1B. When the face member 1A includes the extension portion 9 as in the present embodiment, the weld joint portion J (which has an effect as a weight) between the face member 1A and the head body 1B is on the rear side of the head. Formed. This serves to increase the depth of the center of gravity of the head and does not excessively increase the rigidity of the face portion 4. Accordingly, it is possible to prevent a decrease in the spring effect of the club head.

  In order to effectively exhibit the above-described action, the club head 1 is held at a predetermined lie angle α and loft angle (real loft angle) and is grounded to the horizontal plane HP, so that the extension portion 9 extends in the longitudinal direction of the head. The length D is preferably 7 mm or more, more preferably 10 mm or more, and further preferably 15 mm or more. On the other hand, even if the length D of the extension portion 9 is too large, it becomes difficult to form the face member 1A by plastic working such as forging or pressing, and the productivity may be reduced. From such a viewpoint, the length D of the extension 9 is preferably 30 mm or less, particularly preferably 28 mm or less, and further preferably 25 mm or less.

  In the present embodiment, the face member 1A is made of a first titanium alloy, while the head body 1B is made of a second titanium alloy having a composition different from that of the first titanium alloy. Moreover, each specific gravity G1, G2 of a 1st titanium alloy and a 2nd titanium alloy is less than 4.42.

  As described above, not only one of the face member 1A and the head main body 1B but also a titanium club having a very small specific gravity G1 and G2 as compared with the conventional one is used to easily reduce the weight of a large club head. it can. Therefore, the club head 1 of this embodiment can create a large weight margin for moving the center of gravity of the head to an arbitrary position, and can increase the degree of freedom of weight distribution design.

In particular, both the specific gravity G1 of the first titanium alloy and the specific gravity G2 of the second titanium alloy need to be formed at 4.35 to 4.38 . As a result, a larger weight margin can be secured. Further, the specific gravity G2 of gravity G1 and the second titanium alloy of the first titanium alloy, as both small preferable bur is 4.30 or more in consideration of the prior art such as the current titanium alloy practical . When either one of the specific gravity G1 or G2 is 4.42 or more, a sufficient weight margin cannot be produced while maintaining a large head volume.

  The specific gravity G1 of the first titanium alloy and the specific gravity G2 of the second titanium alloy may be the same or different. In general, the ratio (G1 / G2) between the specific gravity G1 of the first titanium alloy and the specific gravity G2 of the second titanium alloy is preferably about 0.98 to 1.02.

  In the club head 1 of the present embodiment, both the face member 1A and the head main body 1B are made of a titanium alloy, so that both can be easily joined by welding. For this reason, productivity improves. In particular, the head 1 of the present embodiment shows a two-piece structure that is substantially manufactured by the two members 1A and 1B. Such a head 1 is preferable in that the number of joints (welding) can be reduced and the productivity can be further improved.

  Further, in the club head 1 of this embodiment, the face member 1A and the head main body 1B can be improved in characteristics by using a titanium alloy having a composition corresponding to the required characteristics.

  For example, the club head 1 that is enlarged as in the present embodiment has a large spring effect, and its value tends to easily exceed the upper limit defined by the golf rules. In order to reduce the spring effect of the club head 1, it is effective to increase the thickness of the face member 1A. However, this method increases the weight of the club head and reduces the degree of freedom in designing the weight distribution.

  In the present embodiment, a first titanium alloy having a higher elastic modulus than the head body 1B is used for the face member 1A. Thereby, without increasing the thickness of the face portion 3 (that is, without increasing the weight of the face member 1A), the deflection of the face portion 3 at the time of hitting the ball is suppressed, and the spring effect is brought into the golf rules. Can be reduced. Further, it is also preferable that the durability of the face portion 3 can be improved by using a highly elastic first titanium alloy for the face member 1A.

  From the above viewpoint, the ratio (E1 / E2) between the elastic modulus E1 of the first titanium alloy and the elastic modulus E2 of the second titanium alloy is preferably 1.05 or more, more preferably 1.07. As described above, more preferably 1.10 or more. On the other hand, when the elastic modulus ratio (E1 / E2) is increased, there is a possibility that an excessive decrease in the spring effect or a decrease in the durability of the head body 1B may occur. Further, stress concentration at the interface of the joint between the first titanium alloy and the second titanium alloy may occur. From such a viewpoint, the elastic modulus ratio (E1 / E2) is preferably 1.40 or less, more preferably less than 1.37, and still more preferably less than 1.35.

  More specifically, the elastic modulus E1 of the first titanium alloy is preferably 110 GPa or more, more preferably 115 GPa or more, and still more preferably 118 GPa or more. That is, when the elastic modulus E1 is less than 110 GPa, the spring effect is greatly developed and the golf rules may be violated. On the other hand, if the elastic modulus E1 of the first titanium alloy is too large, the spring effect may be significantly reduced, and the flight distance may be impaired. From such a viewpoint, the elastic modulus E1 of the first titanium alloy is preferably 140 GPa or less, more preferably 137 GPa or less, and still more preferably 135 GPa or less.

  In addition, the titanium alloy has a correlation between the elastic modulus and the tensile strength, and when the elastic modulus decreases, the tensile strength tends to decrease. For this reason, in order to ensure sufficient head durability with a titanium alloy having a low elastic modulus, it is necessary to increase the thickness of each part, but this is not preferable because it impairs the degree of freedom in weight distribution design. Therefore, the elastic modulus E2 of the second titanium alloy constituting the head body 1B is preferably 95 GPa or more, more preferably 100 GPa or more, and further preferably 105 GPa or more.

  On the other hand, if the elastic modulus E2 of the second titanium alloy is increased, the spring effect of the club head 1 may be excessively reduced and the flight distance of the hit ball may be impaired as in the case of the face member 1A. From such a viewpoint, the elastic modulus E2 of the second titanium alloy is preferably 120 GPa or less, more preferably 117 GPa or less, and still more preferably 115 GPa or less.

  In this specification, the elastic modulus of the titanium alloy is an elastic deformation region of a stress-strain curve measured according to “Metal material tensile test piece” of JIS Z2201 and “Metal material tensile test method” of Z2241. It shall be calculated from The speed of the crosshead of the tensile tester is 1.0 mm / min.

The elastic modulus (E1 / G1) per unit specific gravity of the first titanium alloy needs to be set to 28.54 GPa or more. When the elastic modulus per unit density (E1 / G1) is less than 27.0GPa, while maintaining the required strength, Ru coma Nandea of the weight of the face member 1A. Conversely, the elastic modulus per unit density (E1 / G1) is useful in weight reduction of the larger the face member 1A, than you deteriorated durability becomes brittle titanium alloy itself, 29.68 GPa or less Needs to be set to

From the same viewpoint, the elastic modulus per unit density of the second titanium alloy (E2 / G2) is, 24.14 GPa or higher, or needs to be set below 25.17 GPa.

As the first titanium alloy and the second titanium alloy having the low specific gravity as described above, the following are preferable.
Ti-8Al-1V-1Mo (specific gravity 4.37, elastic modulus 110 GPa)
Ti-7Al-2V (specific gravity 4.35, elastic modulus 110 GPa)
Ti-7.5Al-2V (specific gravity 4.35, elastic modulus 105 GPa)
Ti-8Al-1V (specific gravity 4.34, elastic modulus 100 GPa)
Ti-8Al-2V (specific gravity 4.35, elastic modulus 105 GPa)
Ti-8Al-1V-1Mo-0.15C (specific gravity 4.37, elastic modulus 118 GPa)
Ti-5.5Al-1Fe (specific gravity 4.38, elastic modulus 125 GPa)
On the other hand, Ti-6Al-4V is well known as a typical titanium alloy having a specific gravity of 4.42 or more.

  Further, the weight W1 of the substantially cup-shaped face member 1A as in the present embodiment is preferably 75 g or less, more preferably 72 g or less, and even more preferably 70 g or less, due to the twisting of the weight margin and the large depth of the center of gravity. Is desirable. On the other hand, if the weight W1 becomes excessively small, the face member 1A is forced to be miniaturized, and there is a tendency that it is difficult to perform a reliable hitting. .

  The weight W2 of the head body 1B joined to the substantially cup-shaped face member 1A is determined in consideration of the design of the center of gravity while maintaining the durability of the club head, but is preferably 110 g or more, more preferably 115 g or more. More preferably, 120 g or more is desirable. On the other hand, if the weight W2 is too large, there is a risk that the swing balance will deteriorate due to the increase in the weight of the club head 1 and it will be difficult to twist out the weight margin, so it is preferably 155 g or less, more preferably less than 150 g. Preferably less than 145 g is desired.

  Further, in order to effectively move the center of gravity of the head, the weight W3 of the weight member 20 is preferably 3 g or more, more preferably 5 g or more, and further preferably 8 g or more. On the other hand, if the weight W3 becomes excessively large, the weight of the club head 1 increases and the swing balance may be deteriorated. Therefore, it is preferably 20 g or less, more preferably less than 18 g, and still more preferably less than 15 g.

  FIG. 4 is an exploded perspective view of a golf club head according to another embodiment of the present invention. The club head 1 of this embodiment includes a face member 1A and a head body 1B, and the face member 1A includes a substantially flat plate that does not have the extension 9. Further, the face member 1A has a contour shape slightly smaller than the peripheral edges 2a to 2e of the face 2, for example. Preferably, the aspect in which the face member 1A occupies 60% or more of the total area of the face 2, more preferably 70% or more, and further preferably 80% or more is preferable.

  Further, in the case of such a substantially flat face member 1A, the weight W1 is preferably about 35 to 60 g. Similarly, in the case of the head body 1B joined to the flat face member 1A, the weight W2 is preferably about 120 to 165 g.

  FIG. 5 is an exploded perspective view of a golf club head 1 according to another embodiment of the present invention. The club head 1 of this embodiment has a three-piece structure including the substantially cup-shaped face member 1A, the head main body 1B, and the crown member 1C. The head main body 1B has a crown peripheral edge 4a1 that forms the periphery of the opening O2 on the crown side provided on the upper surface of the head, the sole main part 5a, the side main part 6, and the hosel part 7. And an opening O in which the face member 1A is disposed. Each part of the head main body 1B of this embodiment is also integrally formed in advance by lost wax precision casting.

  In the present embodiment, the crown member 1C is formed of a third titanium alloy different from the first and second titanium alloys. The third titanium alloy desirably has a higher specific gravity than, for example, the first and second titanium alloys. Thereby, the crown member 1 </ b> C helps to bring the center of gravity of the head toward the rear.

  Although the embodiments of the club head 1 of the present invention have been described above, it goes without saying that the present invention is not limited to the above embodiments and can be implemented in various modes.

In order to confirm the effect of the present invention, wood-type golf club heads were prototyped based on the specifications shown in Table 1, and the following performances were tested. The common specifications for each club head are as follows.
Head volume: 460cm ³
Lie angle 57.5 degrees Real loft angle: 12.0 ° Weight member: Tungsten alloy with a specific gravity of 19.0 In each club head, the thickness of the face member and the head body is changed, and the position of the weight member and The moment of inertia was adjusted by changing the weight.
The test method is as follows.

<Depth of center of gravity>
The linear distance between the head center of gravity GH and the sweet spot SS was measured.

<Inertia moment>
The moment of inertia around the vertical axis passing through the center of gravity of the club head (left and right) and the moment of inertia around the horizontal axis in the toe-heel direction passing through the center of gravity of the club head were measured. The larger the value, the better.
Table 1 shows the test results.

1 is a perspective view of a golf club head showing an embodiment of the present invention. It is the exploded view. FIG. It is a disassembled perspective view of the golf club head which shows other embodiment of this invention. It is a disassembled perspective view of the golf club head which shows other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Golf club head 1A Face member 1B Head main body 1C Crown member 2 Face 3 Face part 4 Crown part 5 Sole part 6 Side part 7 Hosel part

Claims (4)

A golf club head having a hollow structure including a face member having a face for hitting a ball, and a head body having an opening on the front side to which the face member is fixed,
The face member is formed of a first titanium alloy, and the head body is formed of a second titanium alloy having a composition different from that of the first titanium alloy , and the specific gravity of the first titanium alloy G1 is 4.37 to 4.38, and the specific gravity G2 of the second titanium alloy is 4.35 to 4.37 ,
The elastic modulus (E1 / G1) per unit specific gravity of the first titanium alloy is 28.54 to 29.68, and the elastic modulus (E2 / G2) per unit specific gravity of the second titanium alloy is 24.14 to A golf club head, which is 25.17.   The golf club head according to claim 1, wherein an elastic modulus E1 of the first titanium alloy is larger than an elastic modulus E2 of the second titanium alloy.   3. The golf club head according to claim 1, wherein the face member is made of a forged product or a press-formed product, and the head body is made of a cast product. 4. The golf club head according to claim 1, wherein a specific gravity G <b> 1 of the first titanium alloy is larger than a specific gravity G <b> 2 of the second titanium alloy.

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