JP2007244423A - Golf club head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the lower center of gravity and the endurance without spoiling the endurance. <P>SOLUTION: The golf club head 1 has a face part 3 with a face 2 for hitting balls, a crown part 4 linked to the upper rim 2a of the face 2 while making the upper surface of the head and a hollow part i is provided inside. At least a part of the crown part 4 is provided with a composite wall part 9 including a metal wall part 9a with a thickness of 0.3-1.5 mm made of a metal material and a resin wall part 9b with a thickness of 0.1-0.5 mm made of a fiber-reinforced resin disposed on top of its outside. The fiber reinforced resin has reinforcing fibers with a tensile elasticity of 245-900 GPa while the resin content is 20-50%. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a golf club head that can improve durability and feel at impact while reducing the center of gravity.

  In recent years, various golf club heads have been proposed in which a metal material is mainly used and a part thereof is combined with a fiber reinforced resin. For example, Patent Document 1 below discloses a wood-type golf club head having a hollow structure in which a resin member made of fiber reinforced resin is fixed to a crown portion of a club head made of a metal material.

JP 2003-199848 A

  The inventors have made extensive studies to improve durability and feel at impact while further reducing the center of gravity of a golf club head including a portion in which a metal material and a fiber reinforced resin are superimposed on a crown portion. As a result, it was found that it is extremely effective not only to limit the thickness of the metal part and the resin part, but also to limit the tensile elastic modulus and resin content of the reinforcing fiber of the fiber reinforced resin to a certain range. .

  As described above, the main object of the present invention is to provide a golf club head that can satisfy a low center of gravity, durability, and feel at impact on a high level.

  The invention according to claim 1 of the present invention has 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 hollow portion is provided inside. A golf club head, wherein at least a part of the crown portion is arranged to overlap with a metal wall portion made of a metal material having a thickness of 0.3 to 1.5 mm, and to have a thickness of 0. A composite wall portion including a resin wall portion made of a fiber reinforced resin of 1 to 0.5 mm is provided, and the fiber reinforced resin has a tensile elastic modulus of 245 to 900 GPa and a resin content of 20 to 20 It is characterized by 50%.

  The invention according to claim 2 is the golf club head according to claim 1, wherein the composite wall portion has an area of 10% or more of the area of the crown portion.

  A third aspect of the present invention is the golf club head according to the first or second aspect, wherein the metal wall portion is provided over the entire crown portion.

  According to the first aspect of the present invention, at least a part of the crown portion is arranged to overlap with a metal wall portion made of a metal material having a thickness of 0.3 to 1.5 mm and to the outside of the metal wall portion, and the thickness is 0.00. A composite wall portion including a resin wall portion made of 1 to 0.5 mm fiber-reinforced resin is provided. Since such a metal wall portion has a small thickness, the weight can be reduced in the crown portion that forms the upper portion of the head, which helps lower the center of gravity of the head.

  Moreover, the fiber reinforced resin of the resin wall part is limited to a tensile elastic modulus of 245 to 900 GPa and a resin content of 20 to 50%. Therefore, the metal wall portion having a small thickness is effectively reinforced by the high tensile elastic modulus of the reinforcing fiber, and the strength of the crown portion is prevented from being lowered. In addition, the high resin content of the resin wall portion effectively absorbs the vibration of the metal wall portion, thereby improving the feel at impact.

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 of the present embodiment (hereinafter simply referred to as “head” or “club head”) placed in a reference state, FIG. 2 is a plan view thereof, and FIG. The AA expanded sectional view of each is shown.

  The club head 1 includes a face portion 3 having a face 2 which is a surface for hitting a ball, a crown portion 4 which is continuous with the upper edge 2a of the face 2 and forms an upper surface of the head 2, and a head which is continuous with the lower edge 2b of the face 2. A sole portion 5 forming a bottom surface, a side portion 6 extending between the crown portion 4 and the sole portion 5 from the toe side edge 2c of the face 2 through the back face to the heel side edge 2d, and the heel of the crown portion 4 And a neck portion 7 having a shaft insertion hole 7a into which a shaft (not shown) is inserted.

  Further, as shown in FIG. 3, the club head 1 has a hollow structure in which a hollow portion i is provided, and is preferably formed as 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 7 a is arranged in an arbitrary vertical plane VP and tilted at the lie angle with respect to the horizontal plane HP. At the same time, the face 2 is tilted with respect to the vertical plane VP at a loft angle (“real loft angle”, the same shall apply hereinafter) α to bring the head 1 into contact with the horizontal plane HP. Unless otherwise specified in the present specification, the head 1 is described as being in a reference state.

  Further, as shown in FIG. 2, the head longitudinal direction is defined as a direction Fb 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. Relative to each other, the face 2 side is the front (or front side), and the back face BF side is the back (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.

  As is clear from FIG. 3 and FIG. 4 which is an enlarged view of the X portion, a composite wall portion 9 is provided on at least a part of the crown portion 4.

  The composite wall portion 9 has a metal wall portion 9a made of a metal material and having a thickness ta of 0.3 to 1.5 mm, and a thickness tb made of a fiber reinforced resin and arranged on the outside thereof. It is comprised with the resin wall part 9b of 0.1-0.5 mm.

  In the present embodiment, the metal wall portion 9 a is provided in the entire area of the crown portion 4. That is, the aspect in which the crown portion 4 is completely closed by the metal wall portion 9a and no opening or the like is provided is shown. Such a crown portion 4 is preferable in that high durability can be exhibited. However, it goes without saying that an opening may be provided in the metal wall 9a.

  The composite wall portion 9 can greatly reduce the weight of the crown portion 4 that forms the upper portion of the head by the very small metal wall portion 9a having a thickness ta of 0.3 to 1.5 mm, and thus lower the center of gravity G of the head. Can be positioned. In addition, since the metal wall portion 9a having such a small thickness ta is reinforced by the resin wall portion 9b made of a fiber reinforced resin placed on the outer side of the metal wall portion 9a, the metal wall portion 9a exhibits sufficient strength. Both weight reduction and durability can be achieved. In addition, when the resin wall part 9b is overlapped on the inner side (hollow part i side) of the metal wall part 9a, the resin wall part 9b is prevented from resonating in the hollow part i, resulting in an unsounding hitting sound that is not preferred by golfers. Therefore, it cannot be adopted.

  Here, when the thickness ta of the metal wall portion 9a is larger than 1.5 mm, the effect of reducing the weight of the upper portion of the head is reduced. From such a viewpoint, the thickness ta is preferably 1.3 mm or less, more preferably 1.2 mm or less, and still more preferably 1.0 mm or less. On the other hand, since the crown portion 4 is connected to 2a at the upper edge of the face 2 and forms the upper portion of the head, if the thickness ta of the metal wall portion 9a becomes excessively small, the strength of the crown portion 4 is lowered and durability is increased. There is a tendency to get worse. From such a viewpoint, the thickness ta of the metal wall portion 9a needs to be at least 0.3 mm or more, preferably 0.4 mm or more, more preferably 0.5 mm or more.

  The metal material for forming the metal wall portion 9a is not particularly limited. For example, a material having sufficient strength such as stainless steel, maraging steel, titanium, titanium alloy, aluminum alloy, magnesium alloy, or amorphous alloy, particularly Pure titanium, titanium alloy, aluminum alloy or magnesium alloy having high strength is desirable. Similarly, other parts of the club head 1, that is, the face portion 3, the sole portion 4, the side portion 6, the hosel portion 7, and the like can be made of a metal material. Needless to say, two or more kinds of metal materials may be used for the other portions as well as the metal wall portion 9a.

  Further, the resin wall portion 9b is formed with a thickness tb of 0.1 to 0.5 mm in order to effectively reinforce the metal wall portion 9a and at the same time reduce its own weight. That is, when the thickness tb of the resin wall portion 9b is less than 0.1 mm, the reinforcing effect of the metal wall portion 9a cannot be sufficiently obtained. On the other hand, when the thickness tb exceeds 0.5 mm, the effect of reducing the weight at the top of the head tends to decrease. In particular, the sum (tb + ta) of the thickness tb of the resin wall portion 9b and the thickness ta of the metal wall portion 9a is preferably 0.6 mm or more, more preferably 0.7 mm or more. Preferably it is 1.2 mm or less, more preferably 1.1 mm or less.

The thicknesses ta and tb are average thicknesses weighted by the areas, taking into account the areas of the respective thicknesses. For example, the thickness ta of the metal wall portion 9a can be calculated by the following formula.
ta = Σ (tai · Si) / ΣSi (i = 1, 2,...)
Here, tai is an actual thickness of an arbitrary region i of the metal wall portion 9a, and Si is an area of the region i occupied by the actual thickness tai.

  The fiber reinforced resin of the resin wall 9b is a composite material composed of reinforcing fibers and a matrix resin, and has a specific gravity of 1.5 or less, for example, and is smaller than the specific gravity of the metal material of the metal wall 9a. . Therefore, the club head 1 of the present invention can obtain a greater weight reduction effect in the crown portion 4. The reduced weight is distributed, for example, to an appropriate position of the club head 1 so that the position of the center of gravity and the moment of inertia are optimally adjusted, and the degree of freedom in designing the weight distribution is improved.

In order to reinforce the metal wall portion 9a more effectively, a reinforcing fiber having a tensile elastic modulus of 245 to 900 GPa is used for the fiber reinforced resin of the resin wall portion 9b. Here, the tensile elastic modulus of the reinforcing fiber is measured in accordance with “Carbon Fiber Test Method” of JIS R7601. When two or more kinds of fibers are contained, the average elastic modulus calculated by weighting the average elastic modulus of each fiber by its weight ratio is represented by the following formula. .
Average elastic modulus = Σ (Ei · Vi) / ΣVi (i = 1, 2,...)
(Here, Ei is the elastic modulus of the fiber i, and Vi is the total weight of the fiber i.)

  When the tensile elastic modulus of the reinforcing fiber is less than 245 GPa, sufficient rigidity cannot be ensured for the resin wall portion 9b, and the reinforcing effect of the metal wall portion 9a having a small thickness ta tends not to be obtained. From such a viewpoint, the tensile elastic modulus of the reinforcing fiber is preferably 300 GPa or more, more preferably 370 GPa or more. On the other hand, when the tensile elastic modulus of the reinforcing fiber exceeds 900 GPa, there is a tendency that practical strength cannot be obtained, for example, the tensile strength is lowered. From such a viewpoint, the tensile elastic modulus of the reinforcing fiber is preferably 850 GPa or less, more preferably 800 GPa or less.

  Examples of such reinforcing fibers include carbon fibers, glass fibers, aramid fibers, boron fibers, aromatic polyamide fibers, aromatic polyester fibers, ultra high molecular polyethylene fibers, polyphenylene benzoxazole resin fibers (PBO fibers), amorphous fibers, or One or more of titanium fibers and the like can be used, and carbon fibers having a low specific gravity and a high tensile strength are particularly preferable.

  As the matrix resin, for example, a thermosetting resin or a thermoplastic resin is used. Examples of the thermosetting resin include the epoxy resin, unsaturated polyester resin, phenol resin, melamine resin, urea resin, diallyl phthalate resin, polyurethane resin, polyimide resin, or silicon resin. In particular, an epoxy resin is desirable from the viewpoint of strength and rigidity. Examples of the thermoplastic resin include polyamide resin, saturated polyester resin, polycarbonate resin, ABS resin, polyvinyl chloride resin, polyacetal resin, polystyrene resin, polyethylene resin, polyvinyl acetate resin, AS resin. A methacrylic resin, a polypropylene resin or a fluororesin can be employed.

  The resin wall portion 9b of the present invention has a resin content of 20 to 50%. In the present specification, the “resin content” is the weight ratio of the resin to the total weight of the fiber reinforced resin. The weight of the resin can be obtained by chemically decomposing and removing only the resin from the fiber reinforced resin to be measured, taking out only the fiber, and subtracting the total weight of the fiber from the previously measured weight of the fiber reinforced resin. it can. In order to chemically remove the resin from the fiber reinforced resin, for example, a heated nitric acid solution is used. For example, in order to chemically remove the resin from the prepreg before molding, for example, methyl ethyl ketone is used.

  Such a resin wall portion 9b can effectively absorb the vibration of the metal wall portion 9a stacked on the inside due to its high resin content, thereby improving the feel at impact. On the other hand, since the entire area of the hollow portion i is surrounded by a metal material, the sound at the time of hitting the ball is good and the hitting sound is not deteriorated. Here, when the resin content of the resin wall portion 9b is less than 20%, the amount of the resin is reduced, and the vibration of the metal wall portion 9a cannot be effectively absorbed, and as a result, improvement in the feel at impact cannot be expected. On the other hand, when the resin content of the resin wall 9b exceeds 50%, the specific gravity of the fiber reinforced resin of the resin wall 9b increases, and as a result, the effect of reducing the weight of the upper portion of the head decreases. From such a viewpoint, the resin content is more preferably 25% or more, further preferably 30% or more, and the upper limit is more preferably 45% or less, and still more preferably 40% or less.

  The composite wall 9 may be provided on at least a part of the crown 4, but preferably has an area Sh that is 10% or more of the area Sc of the crown 4. When the area Sh of the composite wall portion 9 is less than 10% of the area Sc of the crown portion 4, there is a tendency that the composite wall portion 9 cannot sufficiently reduce the weight and feel at hitting the crown portion 4. From such a viewpoint, the area Sh of the composite wall portion 9 is preferably 30% or more, more preferably 50% or more, particularly preferably 70% or more of the area Sc of the crown portion 4.

  Here, the area Sc of the crown portion 4 is, as shown in FIG. 2, to the horizontal plane HP in a region surrounded by the upper edge 2 a of the face 2 and the outline 6 a of the side portion 6 in the plan view in the reference state. And the hosel part 7 is also included. Similarly, the area of the composite wall portion 9 is also the area projected on the horizontal plane HP.

  Further, as shown in FIGS. 2 and 3, the resin wall portion 9b is preferably provided at a small distance A from the upper edge 2a of the face 2 to the rear of the head. At the time of a miss shot or the like, the upper edge 2a of the face 2 has an opportunity to come into contact with the ball. Therefore, if the front edge 11 of the resin wall portion 9b is located at this portion, the ball directly collides with the front edge 11 to cause damage such as cracks or cracks in the resin wall portion 9b, or even resin There is a possibility that the wall 9b may be peeled off from the metal wall 9a at an early stage. From such a viewpoint, as shown in FIG. 3, the distance A in the head longitudinal direction between the upper edge 2a of the face 2 and the front edge 11 of the resin wall portion 9b is preferably 5 mm or more, more preferably 8 mm. Although it is set above, it is desirable. Thereby, durability of the resin wall part 9b can be improved over a long period of time. If the distance A is too large, the area of the composite wall portion 9 tends to be small. Therefore, it is preferably 30 mm or less, more preferably 20 mm or less, more preferably 15 mm or less.

  In this specification, the “upper edge 2a of the face 2” refers to an edge when it can be clearly identified by an edge or the like, but when it cannot be clearly identified, FIG. As shown in FIG. 5B, in each of the cross-sectional views of the planes P1, P2, and P3 including the sweet spot SS of the head 1 and the center of gravity G of the head, the curvature of the face contour line Lf as shown in FIG. The radius r is obtained in order from the sweet spot SS upward, and the position at which the radius becomes 200 mm for the first time is determined as the upper edge 2a.

  In the club head 1 as described above, for example, as shown in FIG. 6, a head main body 1M made of a metal material and a resin wall portion 9b made of a fiber reinforced resin are separately prepared. For example, it is manufactured by fixing with an adhesive.

  The head main body 1A is formed by appropriately joining two or more parts prepared by casting, forging, pressing or the like, for example.

  The resin wall portion 9b can also be formed by various methods. For example, as shown in FIG. 6, a laminated body in which a plurality of (two in this example) prepreg sheets 20 and 21 are laminated is a mold. It can be made by molding and curing to a desired shape by applying a predetermined temperature and pressure. And the formed resin wall part 9b is fixed on the metal wall part 9a of the crown part 4 using an adhesive agent.

  When the plurality of prepreg sheets 20 and 21 are used, it is desirable to laminate the reinforcing fibers f with different orientation angles θ with respect to the head longitudinal direction Fb. FIG. 7 shows a developed view of the laminated state of the prepreg sheets 20 and 21 forming the resin wall portion 9b. In the present embodiment, the two prepreg sheets P1 are overlapped so that the reinforcing fiber f forms an angle θ of about 45 ° with respect to the head longitudinal direction Fb and crosses each other. Note that the angle θ of the reinforcing fiber f with respect to the head front-rear direction Fb is measured with reference to the reinforcing fiber f projected on the horizontal plane HP.

  Such a resin wall portion 9b is allowed to be deformed by a force in the longitudinal direction of the head generated in the crown portion 4 at the time of hitting a ball, so that the large deformation in which the intersecting reinforcing fibers f form a pantograph shape is allowed. As a result, it can exhibit a high impact absorbing effect. Further, the angle θ is not limited to 45 °. For example, it is possible to intersect with the head longitudinal direction Fb by a combination of 0 ° and 90 °. However, the angle θ is preferably in the range of 30 to 60 °, more preferably 40 to 50 ° in the sense of more reliably mitigating impact upon hitting.

  Moreover, when the resin wall part 9b is formed using the prepreg sheet | seats 20 and 21 of multiple layers, the prepreg sheet | seat which comprises the head outer surface is set to the resin content rate of the inner side prepreg sheet | seat 20 adhere | attached with the metal wall part 9a. It is desirable that the resin content is greater than 21. That is, the inner prepreg sheet 20 having a large resin content can exhibit good adhesion to the metal wall portion 9a and a good vibration absorbing effect, while the outer prepreg sheet 21 having a large proportion of reinforcing fibers causes distortion. It is possible to more effectively reinforce the head outer surface side of the crown portion 4 that tends to increase.

  Further, in the head main body 1A of the present embodiment, a concave portion 10 is formed in which the resin wall portion 9b is disposed, that is, the metal wall portion 9a of the crown portion 4 is recessed in a step shape. The recess 10 preferably includes a front-side recess 10a that can be blinded at least without exposing the front edge 11 of the resin wall 9b to the outside. As a result, it is possible to more reliably prevent the ball from coming into direct contact with the front edge 11 of the resin wall portion 9b, so that peeling of the resin wall portion 9b can be suppressed over a long period of time. However, it goes without saying that the resin wall portion 9b may be fixed to the head main body 1M without forming such a recess 10.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and can be applied to, for example, iron-type, utility-type, and putter-type golf club heads having a hollow structure.

A wood-type driver head having a head volume of 450 cm ³ was manufactured on the basis of the specifications shown in FIG. 1 and Table 1. The head main body and the resin wall were formed as shown in FIG. The head main body was formed by integrally joining a face plate made of Ti-15V-3Cr-3Al-3Sn and the remainder made of pure titanium by CO2 carbon dioxide laser welding.

  The resin wall portions of Examples 1 to 4 and Comparative Examples 1 to 4 were both formed by molding and curing a laminate of two prepreg sheets with a mold. The angles θ of the reinforcing fibers with respect to the longitudinal direction of the head were + 45 ° and −45 °. Moreover, the resin wall part of Example 5 was formed by shape-hardening the laminated body of eight prepreg sheets with a metal mold | die. The angles θ of the reinforcing fibers with respect to the front-rear direction of the head were + 45 ° and −45 °, and these were alternately arranged.

Further, the metal wall portion and the resin wall portion were fixed using a modified epoxy resin adhesive (“EW2010” manufactured by Sumitomo 3M Limited).
The test method is as follows.

<Height of center of gravity>
The height SH of the sweet spot point from the horizontal plane was measured. Smaller is better.

<Durability>
A 45-inch wood-type club was prototyped by attaching a shaft (carbon shaft MP-300 manufactured by SRI Sports) and a grip to each test head. Then, these were attached to a swing robot, and a test of hitting a golf ball (“DDH TOUR SPECIAL” manufactured by SRI Sports) at a head speed of 54 m / s and a sweet spot position was performed. In the evaluation, the number of hit balls until the head was broken was measured. 3000 balls without damage were regarded as acceptable (indicated by “◯”), and the others were indicated by “x”.

<Hit sound>
Twenty golf golf players tried the golf balls (same as above) five by one, evaluated the pitch of the hitting sound by a five-point method with the feeling of each golfer, and showed the average score. The larger the value, the higher the sound and the more the sound is preferred by the golfer.

<Hit feel>
Twenty general golfers (handicap 15 to 25) try the above golf balls (same as above) 5 balls at a time, and evaluate the magnitude of the impact transmitted to the hand by the feeling of each golfer by the 5-point method, These average points are shown. The larger the value, the better the impact transmitted to the hand.
Table 1 shows the test results.

  As a result of the test, the head of the example has a low center of gravity, and is excellent in durability and hitting sound, and a significant effect was confirmed as compared with the comparative example.

It is a perspective view of the standard state of the head which shows the embodiment of the present invention. FIG. It is the AA sectional view. It is the X section enlarged view of FIG. 2A and 2B are diagrams illustrating an upper edge of a face, in which FIG. 1A is a front view of a club head, and FIG. It is a disassembled perspective view of a club head. It is an expanded view of the laminated | stacked prepreg sheet | seat.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Golf club head 2 Face 3 Face part 4 Crown part 5 Sole part 6 Side part 7 Neck part 9 Composite wall part 9a Metal wall part 9b Resin wall part 1M Head main body

Claims (3)

A golf club head having a face portion having a face for hitting a ball, a crown portion connected to an upper edge of the face and forming an upper surface of the head, and a hollow portion provided therein.
At least a part of the crown part has a metal wall part made of a metal material having a thickness of 0.3 to 1.5 mm, and a fiber having a thickness of 0.1 to 0.5 mm arranged on the outside of the metal wall part. A composite wall portion including a resin wall portion made of reinforced resin is provided,
The fiber reinforced resin has a tensile elastic modulus of 245 to 900 GPa and a resin content of 20 to 50%.   The golf club head according to claim 1, wherein the composite wall portion has an area of 10% or more of the area of the crown portion.   The golf club head according to claim 1, wherein the metal wall portion is provided in the entire area of the crown portion.

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