JP4403084B2 - Golf club head - Google Patents

Description

  The present invention relates to a golf club head composed of a head shell made of a metal material and a resin member made of a fiber reinforced resin.

  Conventionally, as shown in FIG. 13, a head shell b made of a metal material and provided with an opening d in the crown, for example, and a resin member c made of a fiber reinforced resin disposed in the opening d A so-called composite golf club head “a” is proposed (see, for example, Patent Document 1 below). The fiber reinforced resin has a smaller specific gravity than a metal material, and thus helps to reduce the weight. The reduced weight can be consumed, for example, to increase the size of the head, or can be distributed to the side portion of the head, such as the toe or heel, or the back face. Therefore, such a composite head has an advantage that the degree of freedom in weight distribution design is high.

  The resin member c is formed, for example, by stacking a plurality of prepregs that have been cut into a predetermined shape and molding the prepreg into a predetermined shape under heat and pressure.

JP-A-2003-250933

  By the way, many golfers in recent years expect the golf club head to improve the flight distance of the hit ball. For this reason, the resilience performance of the head is important, but the conventional composite head has room for further improvement with respect to the resilience performance.

  The present invention has been devised in view of the above-described problems, and is useful for achieving high resilience by relatively reducing the rigidity of the resin member in the longitudinal direction of the head and thus increasing the flight distance. The object is to provide a golf club head.

The invention according to claim 1 of the present invention is made of a metal material, and includes a head shell portion provided with an opening in at least one of a crown portion and a sole portion, and a fiber reinforced resin disposed in the opening portion. A golf club head having a hollow portion provided therein, wherein the resin member is formed using a plurality of prepregs having a size capable of closing the opening, and In the prepreg, the fibers are substantially zero with respect to the head longitudinal direction line, which is a direction along a perpendicular line from the center of gravity of the head to the face surface in a plan view in a reference state where the prepreg is grounded to a horizontal plane at a specified lie angle and loft angle. At least one 0 ° prepreg having an angle of ° and at least two 90 ° prepregs in which the fibers form an angle of substantially 90 ° with respect to the head longitudinal direction line. , And at least one cross prepreg fibers are woven in a direction intersecting, yet the number of the 90 ° direction prepreg, wherein is larger than the number of 0 ° direction prepreg, of 0 ° direction prepreg The 90 ° direction prepreg is arranged outside, and the cross prepreg is used as the outermost layer, and the absolute value of the angle θ of the cross prepreg fiber with respect to the head longitudinal direction line is 30 ° or more and 60 ° or less . A golf club head characterized by that.

  The invention according to claim 2 is characterized in that the elastic modulus of the fibers of the 0 ° prepreg is substantially the same as the elastic modulus of the fibers of the 90 ° prepreg. Head.

  The invention according to claim 3 is characterized in that the basis weight of the fibers of the 0 ° direction prepreg is substantially the same as the basis weight of the fibers of the 90 ° direction prepreg. Golf club head.

  According to a fourth aspect of the present invention, in the golf club head according to the first to third aspects, the elastic modulus of the fiber of the 0 ° direction prepreg is smaller than the elastic modulus of the fiber of the 90 ° direction prepreg. is there.

The invention according to claim 5 is characterized in that when the product of the basis weight of one prepreg fiber and the elastic modulus of the fiber is a stiffness index GP, the total value GP0 of the stiffness index of the 0 ° direction prepreg, The golf club head according to any one of claims 1 to 4 , wherein a ratio GP0 / GP90 to a total value GP90 of the stiffness index of the 90 ° direction prepreg is 0.2 or more and 0.6 or less .

  According to a sixth aspect of the present invention, in the resin member, the difference (N90-N0) between the number N90 of the 90 [deg.] Prepreg and the number N0 of the 0 [deg.] Prepreg is 2 to 4 sheets. A golf club head according to any one of claims 1 to 5.

According to a seventh aspect of the present invention, in the head shell portion, the opening is provided only in the crown portion, and the resin member forms a part of the crown portion. The ratio (S1 / S) between the area S1 of the opening provided in the portion and the area S surrounded by the head outline is 0.5 or more and 0.8 or less . Golf club head.

The invention according to claim 8 includes a head shell portion made of a metal material and provided with an opening in at least one of a crown portion or a sole portion, and a fiber reinforced resin member disposed in the opening, A golf club head having a hollow portion therein, wherein the resin member is formed by using a plurality of prepregs having a size capable of closing the opening, and the prepreg is a specified lie. The fiber makes at least an angle of 0 ° with respect to the head longitudinal direction line, which is a direction along a perpendicular line from the center of gravity of the head to the face surface in a plan view in a reference state in which a ground surface is grounded at an angle and a loft angle. Including one 0 ° prepreg and at least one 90 ° prepreg in which the fibers form an angle of substantially 90 ° with respect to the head longitudinal direction line, When the product of the fiber basis weight and the fiber modulus of elasticity of the prepreg and stiffness index GP, the total value GP0 the stiffness index of the 0 ° direction prepreg, the total value of the stiffness index of the 90 ° direction prepreg GP90 The ratio GP0 / GP90 of the golf club head is 0.2 or more and 0.6 or less .

In the invention according to claim 9, the value of the stiffness index GP0 is 15000 (GPa · g / m ² ) or more and 30000 (GPa · g / m ² ) or less. Golf club head.

In the invention described in claim 10, the value of the stiffness index GP90 is 30000 (GPa · g / m ² ) or more and 90000 (GPa · g / m ² ) or less. The golf club head.

In the golf club head according to claim 1 or 8 , the resin member is formed using a plurality of prepregs, and the fibers are oriented at an angle of substantially 90 ° with respect to the head longitudinal direction line. The rigidity of the resin member in the front-rear direction of the head can be increased by setting the number of the directional prepregs to be larger than the number of 0-degree prepregs in which the fibers are oriented at an angle of substantially 90 degrees with respect to the head longitudinal direction line. It is relatively lower than the rigidity in the direction perpendicular to it. For this reason, the resilience performance of the head is improved by relatively increasing the amount of deflection in the front-rear direction of the resin member disposed on the crown portion or the sole portion at the time of hitting. Thereby, the flight distance of a hit ball can be increased.

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 (hereinafter, simply referred to as “head”) 1 according to the present embodiment in a reference state in which the golf club head 1 is grounded to a horizontal plane as a specified lie angle and loft angle, and FIG. 3 is an AA enlarged sectional view of FIG. 2, and FIG. 4 is an exploded perspective view of the head.

  The head 1 of the present embodiment includes a face portion 3 having a face surface 2 that is a surface for hitting a ball, a crown portion 4 that is continuous with the face portion 3 and forms the top surface of the head, and a bottom surface of the head that is continuous with the face portion 3 and forms the head bottom surface. A sole portion 5, a side portion 6 that extends between the crown portion 4 and the sole portion 5, extends from the toe 3 a of the face portion 3 to the heel 3 b through the back face, and is provided on the heel side of the crown portion 4. Further, a wood type driver such as a hollow driver (# 1) or a fairway wood having a neck portion 7 to which one end of a shaft (not shown) is attached and a hollow portion i provided therein is illustrated. .

  The head 1 is formed using a head shell M made of a metal material and a resin member FR made of a fiber reinforced resin.

  The resin member FR of the present embodiment is exemplified by a resin member FR1 on the crown side that constitutes a part of the crown portion 4. The resin member FR1 on the crown side is a composite material of a matrix resin and a fiber that is a reinforcing material thereof, and has a lower specific gravity than a metal material. Therefore, by constituting a part of the crown portion 4 with the resin member FR, a relatively large weight reduction effect can be obtained on the head upper side. The reduced weight is consumed, for example, for increasing the size of the head shell M, as described above, and can be adjusted to the center of gravity and the moment of inertia by being allocated to the appropriate position of the head shell M. Increase the degree. Further, as in this embodiment, when the resin member FR is provided in the crown portion, it is effective to set the head center of gravity lower.

  The matrix resin is not particularly limited, and examples thereof include thermosetting resins such as epoxy resins and phenol resins, and thermoplastic resins such as nylon resins and polycarbonate resins. The former matrix resin is preferable because it is inexpensive, has good adhesion to fibers, and has a relatively short molding time. Also, the fiber as the reinforcing material is not particularly limited. For example, organic fiber such as carbon fiber, glass fiber, aramid fiber or polyphenylenebenzoxazole resin fiber (PBO fiber), metal fiber such as amorphous fiber or titanium fiber, and the like are used. Carbon fibers having a low specific gravity and a high tensile strength are particularly suitable.

Further, the elastic modulus of the fiber is not particularly limited, but if it is too small, the rigidity of the resin member FR cannot be ensured and the durability tends to decrease. Conversely, if it is too large, the cost increases and the tensile strength tends to decrease. There is. From such a viewpoint, the elastic modulus of the fiber is 50 GPa or more, more preferably 100 GPa or more, further preferably 150 GPa or more, particularly preferably 200 GPa or more, and the upper limit is preferably 450 GPa or less, more preferably 350 GPa or less. . The elastic modulus of the fiber is a tensile elastic modulus, which is a value measured according to “Carbon Fiber Test Method” of JIS R7601. When two or more kinds of fibers are included, the elastic modulus of each fiber is an average elastic modulus calculated by weighting the weight ratio, as represented by the following formula (1).
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.)

  The head shell M is provided with an opening in at least one of the crown 4 or the sole 5, and in this embodiment, the opening O1 is provided in the crown 4 as shown in FIG. Are illustrated. That is, the head shell portion M includes the crown portion 10 that joins the face portion 3, the sole portion 5, the side portion 6, the neck portion 7 and the crown side resin member FR1 and forms the periphery of the opening portion O1. Composed. The head shell M may be formed integrally from the beginning, for example, by casting or the like, or after being formed into two or more parts by a processing method such as forging, casting, pressing or rolling, these are welded. It can also be formed by integrally joining, for example. In the present embodiment, as shown in FIG. 2, the opening O1 has a contour shape including the head gravity center G in a plan view of the reference state.

  The metal material forming the head shell M is not particularly limited. For example, stainless steel, maraging steel, titanium, titanium alloy, aluminum alloy, magnesium alloy, or amorphous alloy can be used. A titanium alloy, aluminum alloy or magnesium alloy having a large thickness is desirable. Further, the head shell M may be formed using not only one kind of metal material but also two or more kinds of metal materials. In this example, a titanium alloy is employed for the head shell M.

  As shown in FIGS. 3 to 4, the crown edge portion 10 of the head shell portion M forms an outer surface portion of the crown portion 4 and, in this embodiment, a crown surface portion 10 a that extends annularly around the opening O <b> 1. And a receiving portion 10b whose surface has a step from the crown surface portion 10a and is recessed toward the hollow portion i. The receiving portion 10b can hold the inner surface side and the peripheral portion of the crown-side resin member FR1. Further, the receiving portion 10b absorbs the thickness of the crown-side resin member FR1 by the step, and helps to finish the crown surface portion 10a and the crown-side resin member FR1 flush with each other.

  The receiving portion 10b is bonded to the crown side resin member FR1. The receiving portion 10b of the present embodiment is provided in an annular shape continuously around the entire circumference around the opening O1, but may be partially interrupted. As a preferred embodiment, the receiving portion 10b is desirably formed with a length of 50% or more of the opening length L along the opening O1, more preferably 60% or more, and even more preferably 70% or more. As a result, a sufficient bonding area between the crown-side resin member FR1 and the head shell M is ensured, which is useful for obtaining a larger adhesive strength.

  Also, the width Wa of the receiving portion 10b measured in the direction perpendicular to the edge of the opening O1 is not particularly limited, but if it is too small, the bonding area between the head shell M and the resin member FR1 on the crown side becomes small, so that the bonding strength is high. On the contrary, if it is too large, the area of the opening O1 cannot be sufficiently secured and the weight reduction effect may be reduced. From such a viewpoint, the width Wa is desirably 5 mm or more, more preferably 10 mm or more, and the upper limit is 30 mm or less, more preferably 20 mm or less, and particularly preferably 15 mm or less. Note that the width Wa of the receiving portion 10b may be constant or may be changed.

  The resin member FR1 on the crown side is exemplified by one that forms part of the crown portion 4 in the present embodiment. In other words, the crown-side resin member FR1 does not need to form the entire crown portion 4, and may constitute at least a part thereof. However, if the area of the resin member FR1 on the crown side (in other words, the opening O1) is too small, there is a tendency that a sufficient weight reduction effect cannot be obtained in the head 1. Therefore, in the plan view of the reference state shown in FIG. 2, the ratio (S1 / S) between the area S1 of the opening O1 provided in the crown portion 4 and the area S surrounded by the head outline is preferably Is preferably 0.5 or more, more preferably 0.6 or more, and the upper limit is, for example, 0.9 or less, preferably 0.8 or less. Such a preferable numerical range can be similarly applied to the case where the resin member FR is directed to the sole portion.

  In the present embodiment, the resin member FR is formed using a plurality of prepregs 11 having a size capable of closing the opening O1. FIG. 5 illustrates the prepreg 11 as a plan view, and FIG. 6 illustrates the laminated body P of the prepreg 11 used for the resin member FR in an exploded manner. The prepreg 11 includes a unidirectional prepreg 12 shown in FIGS. 1A and 1B and a single cross prepreg 13 shown in FIG.

  In the unidirectional prepreg 12 of this embodiment, as shown in FIG. 5A, at least one sheet having front and rear fibers fl oriented substantially at 0 ° with respect to the head longitudinal line BL. As shown in FIG. 5B, at least one 90 ° having a 0 ° direction prepreg 12A and transverse fibers ft oriented at an angle of substantially 90 ° with respect to the head longitudinal direction line BL. Only the directional prepreg 12B is used, and other prepregs are not included. Each of the prepregs 12A to 12B has a size capable of covering the opening O1.

  In the present embodiment, the 0 ° prepreg 12A and the 90 ° prepreg 12B are exemplified by carbon fibers having the same elastic modulus impregnated in the same resin material with the same basis weight. Such prepregs 12A and 12B are formed by, for example, a cutting die or the like so that the angles of the fibers f (referred to simply as the fibers f when collectively referred to) from the long and wide prepreg sheet base are 0 ° and 90 °, respectively. Can be easily prepared by punching with Therefore, the 0 ° prepreg 12A and the 90 ° prepreg 12B can be prepared from one type of prepreg sheet substrate, which is preferable in terms of good productivity. The outline shape of each prepreg can be appropriately limited according to the opening O1, for example.

  As a result of various experiments to improve the resilience performance in the composite head, the inventors have made the number of 90 ° -direction prepregs 12B larger than the number of 0 ° -direction prepregs 12A in the unidirectional prepreg 12. It has been found that the resin member FR can be greatly bent in the front-rear direction of the head at the time of hitting the ball while maintaining the overall strength of the resin member FR at a level where there is no practical problem. The restoring force of the bending of the resin member FR in the head longitudinal direction is applied to the ball as a repulsive force when the ball is hit back. Thereby, the coefficient of restitution of the head 1 is increased and the flight distance of the hit ball is improved. Based on such knowledge, the unidirectional prepreg 12 of the present embodiment is used in such a manner that the number of 90 ° direction prepregs is larger than the number of 0 ° direction prepregs.

  Further, as in the present embodiment, in the head 1 in which the resin member FR is provided only in the crown portion 4, the deflection in the head longitudinal direction is relatively larger in the crown portion 4 than in the sole portion 5. For this reason, the face surface 2 tilts backward at the impact of the ball and the apparent loft angle increases. This helps to increase the launch angle of the ball. In addition, a so-called longitudinal gear effect is generated on the ball due to an increase in the loft angle of the face surface 2 at the time of impact. This serves to reduce the amount of backspin of the ball, and as a result, to obtain a preferable trajectory suitable for improving the flight distance with a high launch angle and low backspin with less blow-up. In this sense, it can be said that the resin member FR is preferably provided only in the crown portion 4 and not provided in the sole portion 5.

  The “head longitudinal direction line BL” is a direction specified in a plan view (FIG. 2) in a reference state in which the head 1 is grounded to the horizontal plane HP at a specified lie angle and loft angle (real loft angle). The direction is a direction along a perpendicular line N extending from the center of gravity G of the head to the face surface 2. Further, the fiber fl in the front-rear direction does not have to be strictly 0 ° with respect to the head front-rear direction line BL, and is −10 ° to + 10 ° (ie, ± 10 °) with respect to the head front-rear direction BL. More preferably, a variation of −5 ° to + 5 ° (that is, ± 5 °) can be included. Similarly, the lateral fibers ft are 80 ° to 110 ° (ie, ± 10 ° variation), more preferably 85 ° to 95 ° (ie, ± 5 ° variation) with respect to the head longitudinal direction BL. Including things.

  Further, in the unidirectional prepreg 12, the difference (N90-N0) between the number N90 of the 90 ° prepreg 12B and the number N0 of the 0 ° prepreg 12A is not particularly limited, but if the value is too small in the resin member FR. It becomes difficult to ensure a large amount of head deflection in the front-rear direction, which tends to reduce the effect of high resilience, and conversely, if it is too large, the rigidity of the resin member FR in the head front-rear direction tends to be significantly reduced and durability is impaired. There is. From such a viewpoint, the difference in the number of sheets (N90-N0) is preferably 1 to 4, more preferably 2 to 4, and further preferably 2 to 3. In this example, N90 is set to 3, N0 is set to 1, and accordingly (N90-N0) is set to 2.

  Further, preferably, as shown in FIG. 6, it is desirable that the 90 ° prepreg 12B is disposed outside the 0 ° prepreg 12A, that is, the 0 ° prepreg 12A is sandwiched between the 90 ° prepregs 12B. This is because the 90 ° -direction prepreg 12B having a large number of used sheets is arranged outside of the 0 ° -direction prepreg 12A having a small number of used sheets, thereby uniformizing the rigidity balance in the thickness direction of the resin member FR and deforming at the time of hitting. This is useful for exerting favorable durability against stress.

  The total number of unidirectional prepregs 12 can be appropriately changed according to the elastic modulus of the fiber and the like, and is not particularly limited. However, if the total number is too small, the rigidity of the resin member tends to be excessively decreased, and conversely, it is too large. However, the rigidity is excessively increased and it is difficult to bend, and the weight is also easily increased. From such a viewpoint, for example, when using carbon fiber, the total number is preferably 4 or more, more preferably 5 or more, and the upper limit is preferably 8 or less, more preferably 7 or less is desirable. In this example, an example in which four unidirectional prepregs 12 are used is shown in FIG.

  In this embodiment, the 0 ° direction prepreg 12A and the 90 ° direction prepreg 12B are both examples in which the fiber f having the same elastic modulus is used. For example, the elastic modulus of the fiber fl of the 0 ° direction prepreg 12A is The elastic modulus of the fiber ft of the 90 ° -direction prepreg 12B can be made smaller. In this embodiment, since the rigidity of the resin member FR in the head front-rear direction can be further reduced, the resin member FR can be bent more greatly and high resilience can be expected.

In this case, if the elastic modulus of the fiber fl in the front-rear direction of the 0 ° direction prepreg 12A is too small, the basic rigidity may be lowered and the durability may be impaired. From such a viewpoint, the elastic modulus of the fiber fl in the front-rear direction is preferably 245 GPa or less, more preferably 150 GPa or less, still more preferably 100 GPa or less, and the lower limit is preferably 50 GPa or more. Further, even if the difference between the elastic modulus E0 of the fiber fl in the front-rear direction and the elastic modulus E90 of the fiber ft in the lateral direction is too large, a large shear force is likely to be generated at the interface between the prepreg layers. Therefore, the elastic modulus ratio (E0 / E90) is preferably 0.50 or more, more preferably 0.60 or more, still more preferably 0.70 or more, and the upper limit is preferably 0.95 or less. More preferably, it is 0.90 or less, and more preferably 0.85 or less. In the present embodiment, the prepreg 12A in the 0 ° direction is used as a single sheet. However, in the case of a plurality of sheets, the effect can be obtained by reducing the elastic modulus of at least one of the fibers. It is preferable to reduce the elastic modulus of all the number of fibers f.

  In this embodiment, the prepreg 11 constituting the resin member FR uses one or a plurality of (one in this example) cross prepregs 13 as prepregs other than the unidirectional prepreg 12. Since the cross prepreg 13 is woven in the direction in which the fibers f intersect, for example, when the prepreg 13 is stretched by applying pressure from one surface of the prepreg, it is easy to obtain uniform and uniform elongation. This is useful for smoothly deforming the prepreg along the mold cavity when the resin member FR is molded by the internal pressure molding method described later. Therefore, it is desirable to arrange one or two cross prepregs 13 on the outermost side of the laminated body of unidirectional prepregs 12. In addition to this, the cross prepreg 13 can also be used for the innermost layer.

  When the cross prepreg 13 is used, the absolute value of the angle θ of the fiber f with respect to the head front-rear direction line BL is preferably 30 ° or more, more preferably 40 ° or more. If the angle θ is less than 30 °, the rigidity of the resin member FR in the front-rear direction of the head tends to increase, and the resilience performance tends to decrease. Since the cross prepreg 13 of this example is woven with the fibers f crossing each other at 90 °, the upper limit of the angle θ is preferably 60 ° or less, more preferably 50 ° or less.

As another embodiment, when the resin member FR includes at least one 0 ° -direction prepreg 12A and at least one 90 ° -direction prepreg 12B, the basis weight of fibers of one prepreg (g / m ² ) and the modulus of elasticity (GPa) of the fiber is the stiffness index GP, the total stiffness value GP0 of the 0 ° -direction prepreg is obtained from the total value GP90 of the stiffness index of the 90 ° -direction prepreg. It is effective to set a smaller value. When two or more kinds of fibers having different elastic moduli are included in one prepreg, the average elastic modulus is used as the elastic modulus. Also in this embodiment, as in the above-described embodiment, the resin member FR has a rigidity in the front-rear direction of the head that is smaller than a rigidity in the lateral direction perpendicular thereto, and greatly deflects the resin member FR in the front-rear direction of the head when hitting a ball. Thus, the coefficient of restitution of the head 1 can be increased.

Here, in order to make the action more reliable, the ratio of the stiffness index ( GP0 / GP90 ) is preferably 0.9 or less, more preferably 0.8 or less, and even more preferably 0.6 or less. . On the other hand, if the ratio (GP0 / GP90) is too small, the rigidity of the resin member FR in the front-rear direction of the head tends to be remarkably lowered and the durability tends to be impaired. From such a viewpoint, the lower limit of the ratio (GP0 / G90) is preferably 0.1 or more, more preferably 0.2 or more, and further preferably 0.3 or more.

Further, the value of the stiffness index GP0 regarding the fiber fl in the front-rear direction is not particularly limited, but if it is too small, the durability of the resin member FR tends to decrease, and conversely if it is too large, the restitution coefficient of the head 1 is reduced. It is difficult to raise enough. From such a viewpoint, the stiffness index GP0 is preferably 10,000 (GPa · g / m ² ) or more, more preferably 15000 (GPa · g / m ² ) or more, and even more preferably 17000 (GPa · g / m ^2). The upper limit is preferably 40000 (GPa · g / m ² ) or less, more preferably 35000 (GPa · g / m ² ) or less, and even more preferably 30000 (GPa · g / m ² ) or less. desirable.

Further, the value of the stiffness index GP90 regarding the fiber ft in the lateral direction is not particularly limited, but if it is too small, the durability of the resin member FR tends to be lowered, and conversely if it is too large, the restitution coefficient of the head 1 is reduced. It is difficult to raise enough. From such a viewpoint, the value of the stiffness index GP90 is preferably 20000 (GPa · g / m ² ) or more, more preferably 30000 (GPa · g / m ² ) or more, and further preferably 34000 (GPa · g / m ² ). m ² ) or more is desirable, and the upper limit is preferably 150,000 (GPa · g / m ² ) or less, more preferably 100,000 (GPa · g / m ² ) or less, and further preferably 90000 (GPa · g / m ² ). The following is desirable.

Further, in each prepreg 11, the basis weight of the fiber f (yarn basis weight) is not particularly limited, but if it is too small, it is necessary to increase the number of prepregs in order to obtain the required strength, and productivity and cost are likely to increase. On the other hand, if it is too large, molding becomes difficult and the defect rate tends to increase. From such a viewpoint, the basis weight of the fiber f of the prepreg 11 is preferably 20 (g / m ² ) or more, more preferably 30 (g / m ² ) or more, and further preferably 40 (g / m ² ). Above, particularly preferably 55 (g / m ² ) or more is desirable, and the upper limit is preferably 200 (g / m ² ) or less, more preferably 150 (g / m ² ) or less, and still more preferably 125 (g / m ² ). g / m ² ) or less is desirable.

Further, in the above-described embodiment, the prepreg has been shown to relatively reduce the rigidity of the resin member FR in the head front-rear direction. However, the present invention is not limited to such an embodiment. For example, the relative relationship between the front and rear fibers fl and the lateral fibers ft remaining in the cured resin member FR may be regulated by the following parameters (a) to (c).
(A) Total weight of fibers contained in unit volume of resin member (b) Sum of elastic modulus contained in unit volume of resin member (c) Product of total weight of fibers of resin member and average elastic modulus

  Regarding the parameter (a), it is effective that the resin member FR is set so that the total weight wl of the fibers fl in the front-rear direction is smaller than the total weight wt of the fibers ft in the lateral direction per unit volume. is there. Here, the unit volume of the resin member FR is the volume of the unit region including the entire thickness of the resin member (the same applies hereinafter). This is useful for reducing the longitudinal rigidity of the resin member FR when the specific gravity and elastic modulus of the fibers fl and ft are approximate.

  Regarding the parameter (b), it is effective that the resin member FR is set such that the sum of the elastic moduli of the fibers fl in the front-rear direction is smaller than the sum of the fibers ft in the transverse direction per unit volume. It is. Accordingly, the resin member FR can have a rigidity in the front-rear direction of the head smaller than a rigidity in the lateral direction perpendicular to the head. In addition, the sum total of the elasticity modulus of the said fiber literally adds all the elasticity modulus of the fiber contained in the said unit volume.

  With respect to the parameter (c), the resin member FR has a product (Wl × El) of the total weight Wl of the fibers fl in the front-rear direction and the average elastic modulus El (Wl × El). It is effective to set it smaller than the product (Wt × Et) of the average elastic modulus Et. The average elastic modulus of the fiber is as described above.

  By restricting at least one of the parameters (a), (b) and / or (c), the resin member FR has a rigidity in the front-rear direction of the head and a rigidity in the lateral direction perpendicular thereto. The resin member FR can be greatly bent in the front-rear direction of the head at the time of hitting and the coefficient of restitution of the head 1 can be increased. Needless to say, each parameter can be easily adjusted by adjusting the number of the 0 ° prepreg 12A and the 90 ° prepreg 12B, the elastic modulus and / or the basis weight of the fiber.

  The resin member FR as described above can be molded by various methods. For example, the prepreg 11 composed of a plurality of sheets can be stacked and a resin member FR having a desired shape can be formed by applying heat and pressure in a mold, for example. Then, the molded resin member FR is integrally fixed to the receiving portion 10b of the opening O1 using, for example, an adhesive.

  Moreover, the resin member FR can also be molded using a so-called internal pressure molding method, for example, as shown in FIG. In the internal pressure molding method, as shown in FIG. 7A, first, the laminate P of the plurality of prepregs 11 is arranged in the opening O1 of the head shell M so as to cover the opening O1. Thus, the head base 1A is preliminarily formed. At this time, the prepreg fibers are arranged at a predetermined angle with respect to the head longitudinal direction. Further, for example, a thermosetting adhesive or a resin primer is applied in advance between the prepreg laminate P and the receiving portion 10b, thereby preventing misalignment of both members in the head base 1A and molding. Helps increase accuracy.

  The preformed head base 1A is put into a mold 20 including, for example, a pair of separable upper mold 20a and lower mold 20b. Preliminary molding can be performed, for example, in a state where the head shell M is mounted in advance on the lower mold 20b. Further, it is desirable to provide the head shell portion M with a through hole 22 that communicates with the hollow portion i in advance. In this example, although the through-hole 22 is shown, for example, provided in the side part 6, it is not limited to this mode. Then, the bladder B is inserted into the hollow portion i from the through hole 22. The bladder B is configured to be able to expand and contract by entering and exiting a pressurized fluid.

  Thereafter, as shown in FIG. 7B, an internal pressure molding process is performed in which the mold 20 is heated and the bladder B is expanded and deformed in the hollow portion i. Thereby, the laminate P of the prepreg sheet that has received the heat and the pressure from the bladder B is deformed along the cavity C of the upper mold 20a and is molded into a desired crown-side resin member FR1, and its peripheral edge The part is integrally bonded to the receiving part 10b. After forming the prepreg, the bladder B is contracted and taken out from the through hole 22. Further, the through hole 22 can be closed later by a badge, a cover or the like with a product name or a decorative pattern of the head.

  When using the internal pressure molding method, for example, as shown in FIGS. 8 and 9A, an auxiliary prepreg 15 is provided on the inner surface 10bi facing the hollow portion of the receiving portion 10b in the opening O1 of the head shell M. It is desirable to paste in advance. The auxiliary prepreg 15 is attached to the inner surface 10bi of the receiving portion 10b with a protruding portion 15b protruding from the edge of the opening O1 to the opening O1 side. The auxiliary prepreg 15 is provided, for example, in at least a part of the periphery of the opening O1, and it is preferable that the auxiliary prepreg 15 is continuously attached in an annular shape around the opening O1.

  Next, as shown in FIG. 9 (B), the prepreg laminate P is attached to the receiving portion 10b so as to cover the opening O1, as in the case described above. In this case, for example, the protruding portion of the auxiliary prepreg 15 15b may be temporarily bonded to the inner surface of the prepreg laminate P. Then, as shown in FIG. 9C, by performing internal pressure molding with the mold 20, the peripheral portion of the resin member FR has an outer piece portion 16a extending from the outer surface side of the receiving portion 10b, and the receiving portion 10b. It can be formed as a bifurcated portion 16 having an inner piece portion 16b extending on the inner surface side. As described above, when the composite head is manufactured, the resin member FR and the head shell portion can be formed in a simple procedure by including the step of previously arranging the auxiliary prepreg 15 having the protruding portion 15b on the inner surface side of the receiving portion 10b. This is useful for manufacturing the head 1 having a strong bonding strength by increasing the bonding area with M.

  Since the auxiliary prepreg 15 needs to be deformed flexibly in contact with the bladder B, the elastic modulus of the fiber f is desirably 245 GPa or less, more preferably 200 GP or less, and even more preferably 150 GPa or less. 50 GPa or more is desirable. The angle of the fibers f of the auxiliary prepreg 15 is not particularly limited, but is preferably about 30 to 60 ° with respect to the head longitudinal direction line BL.

  The resin parts of the prepreg 11 are integrated with each other by various moldings as described above. However, since the fiber f remains, it is sufficiently possible to specify the number of prepregs and the angle of each fiber from the completed head 1. This is the same when, for example, two 90 ° -direction prepregs 12B overlap. In addition, since the resin member FR is generally curved, the angle of the fiber f of each prepreg is obtained by projecting on the horizontal plane HP.

The head 1 of this embodiment can be reduced in weight by using the resin member FR. Accordingly, preferably the volume of the head 200 cm ³ or more, more preferably 300 cm ³ or more, more preferably may be formed of a 380 cm ³ or more. Thereby, the sense of security when it is set can be increased, and the sweet area and the moment of inertia can be increased. Although the upper limit of the volume of the head is not particularly restricted, for example, 500 cm ³ or less is desirable, and when a rule-based restriction of R & A and the USGA good suppressed to 470 cm ³ or less. Although not particularly limited, preferably, in the reference state, a moment of inertia of 2000 (g · cm ² ) around the vertical axis passing through the center of gravity of the head is more than 2000, more preferably more than 3000 (g · cm ² ), still more preferably 3500 ( g · cm ² ) or more is desirable. In the reference state, it is desirable that the moment of inertia around the horizontal axis in the toe and heel directions passing through the center of gravity of the head is 1500 (g · cm ² ) or more, more preferably 2000 (g · cm ² ) or more.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and can be applied to, for example, iron-type, utility-type, and putter-type golf club heads having a hollow structure. . Moreover, in the said embodiment, although the resin member which consists of fiber reinforced resin showed the aspect which consists of the resin member FR1 by the side of a crown, as FIG. 10 shows, for example, a part of opening O1 of the head shell part M is shown. Needless to say, it may be provided across the crown portion 4 and the side portion 6 on the back face side. Further, as shown in FIG. 11, the head 1 is provided with an opening O2 in the sole portion 5 in place of the crown-side resin member FR1 or together with the crown-side resin member FR1, and the sole-side resin member FR2 is provided there. It can also be provided. In the latter embodiment, the moment of inertia about the vertical axis of the head can be further increased.

In order to confirm the effect of the present invention, a wood-type driver head having a head volume of 420 cm ³ was manufactured on the basis of the specifications shown in FIGS. The ratio (S1 / S) between the area S1 of the opening and the head area S was 0.7. About a head shell part and a resin member, it was set as the shape shown by FIGS. Further, the prepregs (excluding auxiliary prepregs) constituting the resin member were based on FIGS. 12 (A) to (C). In the figure, the left side shows the inside of the head, and the right side shows the outside of the head. The angles of the fibers of each prepreg are as shown in the figure and Table 1. The fibers of the prepreg are all carbon fibers.

The head shell portion was integrally cast using Ti-6Al-4V in order to eliminate variations, and then the opening portion was subjected to NC processing to unify the shape. In Example 6, two 10 mm-wide auxiliary prepreg sheets as shown in FIG. 9 were overlapped in advance on the head shell to form a 10 mm protrusion. Then, a composite head was prototyped through a preliminary molding process and an internal pressure molding process, and each head was tested for a coefficient of restitution and durability. The resin member was finished with a thickness of substantially 0.8 mm after molding.
The test method is as follows.

<Restitution coefficient>
U. S. G. A. The coefficient of restitution was calculated in accordance with the Procedure for Measureing the Velocity Ratio of a Club Head for Conformance to Rule 4-1e, Revision 2 (February 8, 1999). The larger the value, the better.

<Durability>
Each test head is mounted on a carbon shaft MP-200 made by SRI Sports to make a 45-inch wood club, and this is attached to a swing robot (Shot Robo 4) made by Miyamae, with a head speed of 51 m / s, A golf ball was hit at the face center position, and the number of hits until the head was damaged (the upper limit was set at 5000) was measured. The larger the value, the better. Table 1 shows the test results.

  As a result of the test, it was confirmed that the head of the example was highly repelled without impairing the durability. Therefore, the head of the present invention can increase the flight distance of the hit ball.

It is a perspective view of the standard state of the head which shows the embodiment of the present invention. FIG. It is AA sectional drawing of FIG. It is a disassembled perspective view of a head. It is a top view which shows an example of a prepreg. It is a disassembled perspective view which illustrates the laminated body of a prepreg. (A), (B) is sectional drawing explaining the internal pressure forming method. It is a top view of the head shell which shows other embodiments of an internal pressure molding method. (A)-(C) is a fragmentary sectional view showing other embodiments of an internal pressure forming method. (A), (B) is the top view of the head which shows other embodiment of this invention, and the rear view seen from the back face side. It is the rear view seen from the back face side of the head which shows other embodiments of the present invention. (A)-(C) is an expanded view which decomposes | disassembles and shows the laminated body of the prepreg of an Example and a comparative example. It is a perspective view of the conventional head.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Golf club head 2 Face surface 3 Face part 4 Crown part 5 Sole part 6 Side part 7 Neck part 10 Crown edge part 11 Prepreg 12 One-way prepreg 12A 0 degree direction prepreg 12B 90 degree direction prepreg 13 Cross prepreg FR Resin member FR1 Crown Resin member on the side

Claims (10)

A head shell part made of a metal material and including an opening provided in at least one of the crown part and the sole part, and a resin member made of a fiber reinforced resin disposed in the opening part, and a hollow part provided therein A golf club head,
The resin member is formed using a plurality of prepregs having a size capable of closing the opening.
The prepreg is substantially free of fibers with respect to the head longitudinal direction line, which is a direction along a perpendicular line from the center of gravity of the head to the face surface in a plan view in a reference state where the prepreg is grounded to a horizontal plane at a specified lie angle and loft angle. At least one 0 ° prepreg with an angle of 0 ° to
At least two 90 ° -direction prepregs in which the fibers make an angle of substantially 90 ° with respect to the head longitudinal direction line;
Including at least one cross prepreg woven in a direction in which the fibers intersect ,
Moreover, the number of the 90 ° direction prepregs is larger than the number of the 0 ° direction prepregs ,
90 ° direction prepreg is arranged inside and outside the 0 ° direction prepreg,
2. The golf club head according to claim 1, wherein the cross prepreg is used as an outermost layer, and an absolute value of an angle θ of the cross prepreg fibers with respect to a head longitudinal direction line is 30 ° or more and 60 ° or less .   The golf club head according to claim 1, wherein the elastic modulus of the fiber of the 0 ° direction prepreg is substantially the same as the elastic modulus of the fiber of the 90 ° direction prepreg.   3. The golf club head according to claim 1, wherein the basis weight of the fibers of the 0 ° direction prepreg is substantially the same as the basis weight of the fibers of the 90 ° direction prepreg.   4. The golf club head according to claim 1, wherein the elastic modulus of the fibers of the 0 ° direction prepreg is smaller than the elastic modulus of the fibers of the 90 ° direction prepreg. When the product of the basis weight of one prepreg fiber and the elastic modulus of the fiber is defined as the stiffness index GP, the total value GP0 of the 0 ° prepreg stiffness index and the sum of the 90 ° prepreg stiffness index The golf club head according to any one of claims 1 to 4, wherein a ratio GP0 / GP90 to the value GP90 is not less than 0.2 and not more than 0.6 .   6. The resin member according to claim 1, wherein a difference (N90-N0) between the number N90 of the 90 [deg.] Prepregs and the number N0 of the 0 [deg.] Prepregs is 2 to 4. A golf club head according to claim 1. The head shell portion has the opening provided only in the crown portion, and the resin member forms a part of the crown portion,
The ratio (S1 / S) of the area S1 of the opening provided in the crown portion to the area S surrounded by the head outline in the reference state plan view is 0.5 or more and 0.8 or less. The golf club head according to any one of 1 to 6. A golf club made of a metal material and including a head shell portion provided with an opening in at least one of a crown portion and a sole portion, and a fiber reinforced resin member disposed in the opening portion, and a hollow portion provided therein A club head,
The resin member is formed using a plurality of prepregs having a size capable of closing the opening.
The prepreg is substantially free of fibers with respect to the head longitudinal direction line, which is a direction along a perpendicular line from the center of gravity of the head to the face surface in a plan view in a reference state where the prepreg is grounded to a horizontal plane at a specified lie angle and loft angle. At least one 0 ° prepreg with an angle of 0 ° to
Including at least one 90 ° prepreg in which the fibers form an angle of substantially 90 ° with respect to the head longitudinal direction line;
When the product of the basis weight of one prepreg fiber and the elastic modulus of the fiber is defined as the stiffness index GP, the total value GP0 of the 0 ° prepreg stiffness index and the sum of the 90 ° prepreg stiffness index A golf club head characterized in that the ratio GP0 / GP90 to the value GP90 is not less than 0.2 and not more than 0.6 . 9. The golf club head according to claim 5, wherein a value of the stiffness index GP0 is 15000 (GPa · g / m ² ) or more and 30000 (GPa · g / m ² ) or less . 10. The golf club head according to claim 5, wherein the value of the stiffness index GP90 is 30000 (GPa · g / m ² ) or more and 90000 (GPa · g / m ² ) or less .

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