JP4651442B2 - Golf club head - Google Patents

Description

  The present invention relates to a golf club head, and more particularly to a hollow wood type golf club head.

  In wood-type golf clubs, flight distance and controllability are important. It is known that the flying distance and controllability of a ball are greatly influenced by the moment of inertia and the depth of the center of gravity about the center of gravity of the golf club head. The moment of inertia and the depth of the center of gravity increase in relation to the volume when the mass of the golf club head is constant and the mass distribution is constant. In the wood type golf club head, in order to increase the volume, a hollow type made of only a metal material such as a titanium alloy has become the mainstream and has become larger.

  Certainly, the hollow type golf club head made of only a metal material has a larger volume than the solid type golf club head represented by the previous Persimmon golf club head. The spot is enlarged and the bend of the hit ball is also reduced.

However, since the above-described metal material has a large specific gravity, the volume of the hollow portion of the golf club head is increased while suppressing an increase in mass, thereby improving the moment of inertia of the entire golf club head and increasing the depth of the center of gravity. There are limits to this.
Therefore, in the following Patent Document 1, by configuring a hollow golf club head with a fiber reinforced resin material (preferably a carbon fiber reinforced resin material) having a large specific strength (tensile strength / specific gravity), an increase in mass is suppressed, In addition, it has been proposed to further increase the size of the golf club head while ensuring strength.
JP 2000-51405 A

However, a golf club head made of a fiber reinforced resin material is not sufficient in terms of hitting sound and scratch resistance compared to a golf club head made of titanium alloy.
Therefore, there is a method of improving the hitting sound and scratch resistance by bonding a metal to the fiber reinforced resin material, but in that case, the bonding strength between the fiber reinforced resin material member and the metal material member becomes a problem. In particular, it has been difficult to stably maintain strength around the face where the impact is most applied.

  An object of the present invention is to solve the above problems. That is, it is an object of the present invention to increase the volume of the hollow portion while suppressing an increase in mass and realize an increase in the moment of inertia and / or an increase in the depth of the center of gravity in a hollow golf club head. An object of the present invention is to provide a golf club head having sufficient performance in terms of scratch resistance and strength.

As a result of various studies on the method for joining the fiber reinforced resin material member and the metal material member, the present inventors have found that the edge portion of the fiber reinforced resin material member has an adhesive layer on the outer surface of the metal material member. If the adhesive layer is exposed thickly between the end face of the fiber reinforced resin material member and the metal material member in the joint portion that adheres, the adhesive layer may crack when an external force is applied. There was a problem that, when an attempt was made to prevent the occurrence of cracks by reducing the thickness of the adhesive layer, there was a case where peeling occurred between both members when an external force was applied. As a result of intensive studies to solve such problems, the present invention has been completed.
That is, the golf club head of the present invention is a hollow golf club head having a joint portion in which the edge portion of the fiber reinforced resin material member is bonded and integrated to the outside of the metal material member via the adhesive layer, The thickness of the adhesive layer is 0.05 to 1 mm, the thickness of the adhesive layer at the joint is increasing inward from the edge of the fiber-reinforced resin material member , and The thickness at the thinnest part is 0.05 to 0.5 mm .

According to the present invention, a hollow golf club head excellent in bonding strength between a metal material member and a fiber reinforced resin material member can be obtained. That is, even when an external force is applied, cracks and peeling do not occur at the joint between the metal material member and the fiber reinforced resin material member, and the durability is excellent.
Therefore, the golf club head of the present invention is excellent in strength and has good hitting sound and scratch resistance. In addition, since the fiber reinforced resin material member has a large specific strength, it is possible to increase the volume of the hollow portion while suppressing an increase in mass, realizing a larger moment of inertia and a greater depth of the center of gravity, A golf club head suitable for a driver or the like having a very small bend and a small flight distance loss can be obtained.

The present invention will be described in detail below.
1 to 6 show a first embodiment of a golf club head according to the present invention. FIG. 1 is a front view, FIG. 2 is a top view, and FIG. 3 is a right side view as viewed from the right side in FIG. 4 is a bottom view, FIG. 5 is a left side view seen from the left side in FIG. 1, and FIG. 6 is a cross-sectional view taken along the line AA in FIG.
The golf club head is roughly divided into a face 1, a sole 2, a crown 3, and a neck 4. In the example shown in FIGS. 1 to 6, the face 1, the sole 2, and the neck 4 are formed of a metal material, and the crown 3 is formed of a fiber reinforced resin material. In the figure, reference numeral 11 denotes a metal material member having a shape in which the face 1, sole 2 and neck 4 of the hollow golf club are integrated, and reference numeral 12 denotes a fiber reinforced resin material member forming the crown 3.

Of the edge portions of the fiber reinforced resin material member 12, the boundary portion 12a with the face 1 and the boundary portion 12b with the neck 4 are bonded onto the outer surface of the edge portion of the metal material member 11, as shown in FIG. The edge part of the fiber reinforced resin material member 12 is bonded and integrated through the agent layer 13. The joint portion in which the edge portion of the fiber reinforced resin material member 12 is bonded to the outside of the metal material member 11 in this manner is hereinafter referred to as an outer joint portion 15.
On the other hand, the boundary portion 12c with the sole 2 among the edge portions of the fiber reinforced resin material member 12 is formed on the inner surface of the edge portion of the metal material member 11 via the adhesive layer 14 of the fiber reinforced resin material member 12. The edge portion is bonded and integrated. The joint portion in which the end edge portion of the fiber reinforced resin material member 12 is bonded to the inside of the metal material member 11 in this manner is hereinafter referred to as an inner joint portion 16.

<Fiber-reinforced resin material member>
Examples of the fiber reinforced resin material constituting the fiber reinforced resin material member 12 include a matrix resin such as an epoxy resin, an unsaturated polyester resin, a vinyl ester resin, or the like on a reinforcing fiber such as carbon fiber, glass fiber, aramid fiber, or polyester fiber. And fiber reinforced resin impregnated with. In terms of strength, it is preferable to use carbon fibers as reinforcing fibers. The matrix resin is preferably an epoxy resin from the viewpoint of strength and moldability.

The fiber reinforced resin material member 12 is preferably formed by molding a laminate in which sheet-like intermediate materials (prepregs) are laminated. In addition, in the laminate, an intermediate material (prepreg) in which the orientation directions of the reinforcing fibers are different from 0 °, 90 °, −45 °, and 45 ° is combined, or an intermediate material of 0 °, 60 °, and −60 ° is combined. For example, a pseudo-isotropic laminated structure is preferable because a balanced strength can be obtained.
In particular, in a golf club head, it is preferable to use a combination of intermediate materials in which carbon fibers are oriented in two orthogonal directions (0 °, 90 °) in order to ensure substantially sufficient impact resistance. As such an orthogonal bi-directionally oriented carbon fiber, an orthogonal bi-directional woven fabric can be used in addition to a 0 °, 90 ° laminate or ± 45 ° laminate of carbon fibers oriented in one direction.
For example, the use of carbon fiber bidirectional reinforced epoxy resin with an epoxy resin as the matrix resin, the specific strength (tensile strength (unit; kg / ^mm 2) / specific gravity) of the fiber-reinforced resin material 35~60kg / mm ² Obtainable.

<Metal material members>
Examples of the metal material constituting the metal material member 11 include a titanium alloy, an aluminum high strength alloy, and stainless steel. In terms of volume and weight required for the golf club head, titanium alloy is preferable for driver wood, and stainless steel is preferable for fairway wood in terms of balance between strength and specific gravity.
The thickness of the metal material member 11 is preferably 0.5 mm or more, more preferably about 1.0 to 2.0 mm, in order to obtain good strength while suppressing an increase in mass. In particular, the thickness of the metal material member 11 constituting the face 1 is preferably 1.5 mm or more, and more preferably about 2.0 to 4.0 mm.

In the outer joint portion 15 and the inner joint portion 16, the surface (edge portion) of the metal material member 11 in the region (edge portion) in contact with the adhesive layers 13 and 14 is the outer surface at the outer joint portion 15 and the inner surface at the inner joint portion 16. It is preferable that the metal surface is degreased with methyl ethyl ketone or acetone and the metal surface roughness (Ra) is 1 to 20.
Moreover, in the area | region (edge edge part) which contacts the adhesive bond layers 13 and 14 on the metal material member 11, you may provide a recessed part partially, and can aim at the retainability improvement of an adhesive agent by this. In this case, the depth of the recess is preferably 0.05 to 0.5 mm. If it is less than 0.05 mm, the adhesive retainability improving effect cannot be sufficiently obtained. If the thickness exceeds 0.5 mm, particularly when bonding is performed using a mold at the outer joint, it is difficult to apply pressure in the direction in which the fiber reinforced resin material member 12 is pressed against the outer mold from the inside of the hollow portion. The surface smoothness of the reinforced resin material member 12 is likely to be affected.

<Adhesive layer>
The thickness of the adhesive layer 13 in the inner joint portion 16 is preferably in the range of 0.05 to 1 mm, more preferably in the range of 0.1 to 0.5 mm. If the thickness is less than the above range, the adhesive layer 13 is likely to have thickness unevenness, resulting in a decrease in adhesive strength, and easy peeling.
If it is thicker than the above range, the adhesive layer 13 is liable to cause a reduction in rigidity, and cracks are likely to occur. Also, the outflow of the adhesive resin (adhesive) is likely to occur.

The adhesive layer 13 in the outer joint portion 15 has a thickness in the range of 0.05 to 1 mm. Thereby, stable adhesive strength can be obtained. If the thickness is less than 0.05 mm, uneven thickness of the adhesive layer 13 is likely to occur. As a result, the adhesive strength is reduced and peeling is likely to occur. If it exceeds 1 mm, the rigidity of the adhesive layer 13 is likely to decrease, and cracks and the like are likely to occur. Also, the outflow of the adhesive resin (adhesive) is likely to occur.
The adhesive layer 13 in the outer joint 15 is configured such that its thickness increases inward from the edge of the fiber reinforced resin material member 12. The thickness at the thinnest part of the adhesive layer 13 (the edge of the fiber reinforced resin material member 12) is preferably 0.05 to 0.5 mm, and more preferably 0.05 to 0.2 mm. It is.
According to this configuration, high bonding strength can be obtained, peeling can be prevented, and occurrence of cracks in the adhesive resin layer due to impact at the edge of the fiber reinforced resin material member 12 can be suppressed. For example, an edge portion of the fiber reinforced resin material member 12 exists in the vicinity of a corner that forms a boundary between the face 1 and the crown 3, and the surface coating of this portion is performed on both the metal material member 11 and the fiber reinforced resin material member 12. It is effective when straddling.

  Specifically, for example, as shown in FIG. 12, the thickness of the adhesive layer 13 is configured to gradually increase from the edge of the fiber reinforced resin material member 12 inward (indicated by an arrow in the figure). It is preferable to do. In these drawings, the fiber reinforced resin material member 12 is composed of a laminate of sheet materials, specifically, a laminate in which sheet-like prepregs are laminated.

Alternatively, as shown in FIG. 14, the fiber reinforced resin material member 12 is made of a laminate of sheet materials, and the number of sheets laminated in the outer joint portion 15 is the end from the inside of the fiber reinforced resin material member 12. A configuration that gradually increases toward the edge (indicated by an arrow in the figure) is also preferable. The adhesive layer 13 in the example of this figure is thicker stepwise from the edge of the fiber reinforced resin material member 12 inward.
Alternatively, by forming the configuration shown in FIGS. 12 and 14 using a fiber reinforced resin material member 12 ′ made of a laminate of uncured sheet materials and curing the fiber reinforced resin material while applying pressure, FIG. As shown in FIG. 15, it is also preferable that the end portion of the fiber reinforced resin material member 12 is compressed to reduce the thickness of each layer. The thickness of the adhesive layer 13 in the configuration of FIGS. 13 and 15 gradually increases inward from the edge of the fiber reinforced resin material member 12.

  The material of the adhesive layer 13 may be a liquid adhesive. However, if application spots or thickness spots of the liquid adhesive are generated, the adhesive strength is reduced. Therefore, it is necessary to pay sufficient attention at the time of application so that they do not occur. Examples of the liquid adhesive include a product name manufactured by 3M Corporation; Scotch Weld 2214 and the like.

Alternatively, an adhesive previously formed into a film can be preferably used. Since the adhesive in the form of a film has a uniform thickness, it is difficult for unevenness in thickness to occur, and a stable adhesive strength can be obtained by adhering with a predetermined adhesive pressure.
Examples of the resin constituting the film adhesive include an epoxy resin, a polyester resin, and an acrylic resin, and an epoxy resin is preferable in terms of adhesive strength. More preferably, the epoxy resin composition contains an epoxy resin component, a curing agent component, and an elastomer component. Examples of the elastomer component include Carboxy-Terminated Butadiene Acrylonitrile Copolymer (CTBN).

In addition, it is preferable that the film-form adhesive includes a base material made of a nonwoven fabric or a woven fabric because the handleability and adhesive retention of the film-form adhesive are improved. Further, when stress is applied to the cured adhesive layer 13, even if a minute crack occurs, the progress of the crack can be suppressed, so that the breaking strength of the adhesive layer 13 can be improved. .
Polyester fiber, nylon fiber, aramid fiber, acrylic fiber, glass fiber, and the like can be used as the material for the nonwoven fabric and woven fabric used for the adhesive layer 13, but the material is not limited to this.

In particular, it is known that golf club heads receive a load of about 1 ton in 5 10000 seconds when hitting a ball. In order to obtain a golf club head having durability to withstand this impact, it is preferable to use an adhesive having a shear adhesive strength of 15 MPa or more as an adhesive to be used. The shear bond strength is more preferably 20 MPa or more. The upper limit of the shear bond strength is not particularly limited, but is practically about 45 MPa.
Here, the “shear adhesive strength” in the claims and the specification of the present invention is a value obtained by measurement according to Federal Specification MMM-A-132B (1 April 1994).
An example of an adhesive having a shear bond strength of 15 MPa or more includes a product name; NB-101 manufactured by Newport Adhesive Co., Ltd.

<Manufacturing method>
The metal material member 11 is preferably formed in advance by casting, forging, or the like.
The outer joint portion 15 can be manufactured by (1) a method in which the inner surface of the pre-cured fiber reinforced resin material member 12 and the outer surface of the metal material member 11 are bonded and integrated through the adhesive layer 13, or (2) An uncured fiber reinforced resin material member 12 ′ may be formed on the outer surface of the metal material member 11 through an adhesive layer 13 and cured by simultaneously curing the fiber reinforced resin material.

In the method (1), for example, as shown in FIGS. 12 and 14, the thickness of each sheet material constituting the fiber reinforced resin material member 12 is uniform in the outer joint portion 15. Suitable for forming a configuration.
For example, as shown in FIG. 13 and FIG. 15, the method (2) described above is performed by using a sheet material constituting the fiber reinforced resin material member 12 at the edge of the fiber reinforced resin material member 12 of the outer joint 15. It is suitable for forming a structure that is more densely compressed than the portion.

  Specifically, the configuration shown in FIG. 13 can be formed as follows. That is, in the method (2), the uncured fiber reinforced resin material member 12 ′ and the metal material member 11 are overlapped via the adhesive layer 13, and the uncured fiber reinforced resin material member 12 ′ When the metal material member 11 is pressed in the direction in which the metal material member 11 approaches each other and the two are bonded together and the fiber reinforced resin material is cured, the pressing force increases from the inside of the fiber reinforced resin material member 12 toward the edge. Create a pressure gradient. In this way, even if the thickness of the adhesive layer 13 before curing is uniform, the thickness of the adhesive layer 13 after curing is set to the end of the fiber reinforced resin material member 12 as shown in FIG. It can be gradually increased inward from the edge. Further, in the outer joint 15 after curing, the thickness of the fiber reinforced resin material member 12 becomes thinner toward the end edge of the fiber reinforced resin material member 12. The fiber content increases as the value approaches, and as a result, the crack resistance strength of the edge portion is further improved.

Specifically, the configuration shown in FIG. 15 can be formed as follows. That is, when the uncured fiber reinforced resin material member 12 ′ is manufactured by laminating the sheet materials, a plurality of strip-shaped sheet materials having different widths along the edge are stepped on the edge of the inner surface. The sheet material is laminated so that the number of the sheet material is increased as it is closer to the edge of the fiber reinforced resin material member 12 ′. Then, the inner surface of the fiber reinforced resin material member 12 ′ is overlaid on the metal material member 11 with the adhesive layer 13 interposed therebetween. A cross section in this state is shown in FIG. 14, for example. Then, while pressing the uncured fiber reinforced resin material member 12 ′ and the metal material member 11 in a direction approaching each other, the fiber reinforced resin material is cured at the same time as bonding them together. In this way, as shown in FIG. 15, the thickness of the adhesive layer 13 in the outer joint 15 is configured to increase inward from the edge of the fiber reinforced resin material member 12. Can do.
Further, according to such a configuration, the fiber content in the fiber reinforced resin material member 12 is larger in the outer joint portion 15 after curing, the closer to the edge portion of the fiber reinforced resin material member 12, the resistance of the edge portion. The crack strength is further improved.
In the example of FIG. 15, a plurality of belt-like sheet materials are laminated on the inner surface of the fiber reinforced resin material member 12, but these may be laminated on the outer surface, and the fiber reinforced resin material member 12 that is a laminate. It may be provided as an intermediate layer.

The inner joint portion 16 overlaps the end portion of the uncured fiber reinforced resin material member 12 ′ on the inner surface of the metal material member 11 with the adhesive layer 14 interposed therebetween, so that the fiber reinforced resin material is cured and the two members are bonded. It is preferable to form by the method of performing simultaneously. In this case, as shown in FIG. 6, it is preferable to chamfer (chamfer) the end face of the metal material member 11 in the inner joint portion 16. Thereby, while making the adhesion area of an end surface large, the fiber bending of the prepreg (intermediate material) which comprises the fiber reinforced resin material member 12 is relieve | moderated, stress concentration can be reduced and intensity | strength improvement can be aimed at.
As the material of the adhesive layer 14, the same material as that of the adhesive layer 13 described above can be used.

  The golf club head of the present embodiment can be manufactured, for example, by the method (2) as follows. Hereinafter, although the case where a carbon fiber bidirectional reinforcement epoxy resin is used as the fiber reinforced resin material member 12 will be described as an example, the present invention is not limited thereto.

The metal material member 11 is molded in advance, and the fiber reinforced resin material member 12 cuts the required number of carbon fiber bi-directional reinforced epoxy resin intermediate materials (prepreg) into a crown shape.
A film-form adhesive for forming the adhesive layer 13 of the outer joint 15 and the adhesive layer 14 of the inner joint 16 is cut into a required shape, and the outer joint of the outer surface of the metal material member 11 is cut. 15 and a region constituting the inner joint 16 of the inner surface of the metal material member 11. And the edge part of the said prepreg is piled up on this adhesive agent.
Subsequently, after inserting a bag made of natural rubber or the like into the hollow portion of the golf club head from the shaft mounting hole in the neck or the hole provided in the metal material member 11 as appropriate, the golf club head is placed in the female mold. Set and clamp.

  Next, the mold is placed in a heating furnace, and when heated, pressurized air is pressed into the bag to cure the prepreg (intermediate material) while pressing it toward the mold. By forming the portion 15 and the inner joint portion 16, a golf club head is obtained. In particular, the outer joint 15 is provided with a movable pressurizing part inside the female mold or movable pressurizing the entire upper and lower molds so that sufficient pressure is applied to the prepreg (intermediate material) during bonding. It is preferable to provide a mechanism.

7 to 11 show a golf club head according to a second embodiment of the present invention. FIG. 7 is a front view, FIG. 8 is a top view, and FIG. 9 is a right side view seen from the right side in FIG. 10 is a bottom view, and FIG. 11 is a left side view seen from the left side in FIG.
In the figure, reference numeral 21 denotes a metal material member having a shape in which the parts of the face 1 and the neck 4 of the hollow golf club head are integrated, and reference numeral 22 is a fiber reinforcement having a shape in which the parts of the sole 2 and the crown 3 are integrated. The resin material member is shown.
In this embodiment, the end edges of the fiber reinforced resin material member 22 are all bonded and integrated on the outer surface of the metal material member 21 via an adhesive layer to form an outer joint portion.

The present embodiment can be manufactured in the same manner using the same material as the first embodiment except that the shape of the metal material member 21 and the shape of the fiber reinforced resin material member 22 are different from each other.
In the present invention, it is arbitrary which portion of the hollow golf club head is made of a metal material, but from the viewpoint of the hitting sound, the face 1 is preferably made of a metal material. From the viewpoint of scratch resistance, the sole 2 is preferably made of a metal material.
Further, a part of the hollow golf club head can be made of a material other than the metal material member and the fiber reinforced resin material member, but it is made of a metal material as in the first and second embodiments. It is preferable that the entire remaining portion is made of a fiber reinforced resin material.

According to the first and second embodiments, a golf club head having excellent bonding strength between the metal material member and the fiber reinforced resin material member and good hitting sound and scratch resistance can be obtained. In addition, since a fiber reinforced resin material member having a high specific strength is used, it is possible to increase the volume of the hollow portion while suppressing an increase in mass, realizing a larger moment of inertia and a greater depth of the center of gravity, It is possible to realize a golf club head suitable for a driver or the like that has a very small bend and a small flight distance loss.
In particular, the configuration of the first embodiment is advantageous not only in terms of the face but also in terms of scratch resistance in the sole, and the configuration of the second embodiment is advantageous in terms of moment of inertia and depth of the center of gravity.

For example, in the first or second embodiment, a titanium alloy is used as the metal material, and a carbon fiber bi-directionally reinforced epoxy resin having a carbon fiber content of 50% by volume and a specific strength of 35 kg / mm ² is used as the fiber reinforced resin material. When a hollow golf club head having a volume of 400 cc and a mass of 190 g is produced using an adhesive in the form of a film as an adhesive, the moment of inertia is 4 × 10 ⁻⁴ kg · m ² , and the moment of inertia is sufficiently large. Can be applied to the golf club head, and the depth of the center of gravity can be set sufficiently large. And since adhesion | attachment shall have sufficient intensity | strength, there is no possibility of destruction of the golf club head by the impact at the time of a hit | damage.
In addition to the carbon fiber bidirectionally reinforced epoxy resin, the specific strength has a value of 30 kg / mm ² or more, and although it is expensive, a carbon fiber reinforced carbon composite material can be used for the golf club head of the present invention. (C / C composite).

As described above, the golf club head of the present invention has a volume of 300 cc or more and can increase the moment of inertia and the depth of the center of gravity as compared with the conventional one. Preferably, the value of the moment of inertia is 4 × 10 ⁻⁴ kg. · ^m is ² or more. Therefore, even when the ball is hit slightly off the sweet spot on the face of the golf club head, the bending of the ball is small, and the decrease in the flight distance due to the bending of the ball can be reduced. It is also possible to provide a balance weight for adjusting the center of gravity.
According to the present invention, a golf club head having a mass of 200 g or less, preferably 170 to 195 g, and a volume of 300 to 500 cc, preferably 350 to 460 cc can be obtained.

Hereinafter, the effect of this invention is explained in full detail.
When the moment of inertia is increased and the depth of the center of gravity is increased, the golf club head has a smaller bend of the hit ball, thereby reducing the flight distance.
In order to increase the moment of inertia of the golf club head and the depth of the center of gravity, there is a method of increasing the size of the golf club head, but when the size of the golf club head is increased, the mass of the golf club head is also increased. And swinging becomes difficult.
Since the golf club head of the present invention has a hollow structure, it is suitable for increasing the volume without increasing the mass.

In fact, it is said that the upper limit of the mass of the golf club head is 200 g. Therefore, suppose that the golf club head mass is 200 g, the volume that is an index indicating the size of the golf club head is 300 cc, and the moment of inertia that is another index indicating the size of the golf club head is 3 × 10 ⁻⁴ kg · m. ^If a large hollow golf club head such as ² is made of only a metal material such as a titanium alloy, an aluminum high-strength alloy, and stainless steel, the thickness of the golf club head must be reduced. There is a risk of destruction by the impact of.
Further, when a hollow golf club head having a larger size and an inertia moment of 4 × 10 ⁻⁴ kg · m ² is to be produced using only the above metal material, the thickness of the face portion or the like is 1 mm or less. It has been experimentally confirmed that there is a risk of actual damage when hit.

The reason why it is difficult to increase the moment of inertia in such a hollow golf club head made of only the above metal material is considered to be that these metal materials have large specific gravity and small specific strength (tensile strength / specific gravity).
Actually, these metal materials have a specific strength of 14 to 20 kg / mm ² , and in a golf club head made of only a metal material having such a specific strength, the upper limit of the moment of inertia is 3 × 10 ⁻⁴ kg · m. ² or so. Therefore, it is very difficult to increase the size (volume) of the golf club head made only of a metal material to increase the moment of inertia beyond this. Even if only the shape of the moment of inertia is large, the depth of the center of gravity is small. As a result, the degree of freedom of the center of gravity position is almost lost, and the optimum center of gravity position design cannot be performed.

The fiber reinforced resin material is a material having a high specific strength. In particular, as a material having a specific strength of 30 kg / mm ² or more, a carbon fiber reinforced resin material is suitable, and an inertia moment of 4 × 10 ⁻⁴ kg · m ² can be achieved. Thereby, the flight distance and controllability can be improved by increasing the moment of inertia and also increasing the depth of the center of gravity. However, a golf club head made of a fiber reinforced resin material is not sufficient in hitting sound and scratch resistance as compared with the current golf club head made of titanium alloy.
According to the present invention, by replacing a part of a golf club head made of a fiber reinforced resin material with a metal material, performance such as a hitting sound and scratch resistance is improved, and the characteristics of both the metal material and the fiber reinforced resin material are improved. In addition, a golf club head having excellent performance can be obtained. That is, the hitting sound and scratch resistance are improved in the metal material portion, and the use of the fiber reinforced resin material makes it lighter and stronger, and can increase both the moment of inertia and the depth of the center of gravity.

  Hereinafter, the present invention will be described in more detail using examples, but the present invention is not limited to these examples.

Example 1
A metal material member 11 having the configuration shown in FIG. 1 was prepared. The metal material member 11 is made of a titanium alloy, and has a face, a sole, and a neck integrated. Hereinafter, it is simply referred to as a titanium member.
On the other hand, after cutting a prepreg [Mitsubishi Rayon Co., Ltd., product name: Pyrofil TR350H175 (resin content 35 mass%)] into a crown shape, four layers are laminated alternately so that the fiber orientation direction becomes 0/90 °. Then, an intermediate material (prepreg) forming a fiber reinforced resin material member was prepared. Hereinafter, it is simply referred to as an intermediate material. Of the inner surface of the intermediate material, on the crown face side region having a width of 15 mm to be bonded to the titanium member, that is, on the crown face side region to be bonded to the titanium member, the width of 10 mm, 7 mm, A 4 mm strip-shaped prepreg [Pyrofil TR1120 350GMP (resin content: 40% by mass) manufactured by Mitsubishi Rayon Co., Ltd.] was superposed in a step shape.

Separately, NB-101 (product name, shear bond strength 30 MPa, thickness 0.3 mm) manufactured by Newport Adhesive Co., Ltd. was prepared as an adhesive in the form of a film.
And the adhesive agent of the film form was laminated | stacked on the area | region which comprises the outer side junction part of the inner surface of the said intermediate material, and the area | region which comprises the inner side junction part of the outer surface of the said intermediate material.
After that, a nylon bag for applying an internal pressure through a hole provided in the sole of the titanium member is disposed, and the edge portion of the intermediate material laminated with the adhesive in the form of the film and the edge portion of the titanium member are temporarily connected. They were stacked and placed in a split female mold for molding and clamped. For mold clamping, a movable part was used and a load of 1 ton (1000 kg) was applied.

Next, this female mold was heated and heated under the conditions of a temperature of 120 ° C. and a time of 2 hours, and at the same time, pressurized air having a pressure of 3 kgf / cm ² (about 294 × 10 ³ Pa) was injected into the nylon bag. After curing, the mold was opened to obtain the desired golf club head.

The obtained golf club head had a mass of 190 g, a volume of 400 cc, a moment of inertia of 4.0 × 10 ⁻⁴ kg · m ² , and a center of gravity depth of 38 mm. After the golf club head was painted, a golf club shaft was attached to obtain a golf club.
This golf club was attached to a swing robot, and it was not damaged even if it was repeatedly hit 1000 times at a head speed of 48 m / sec.
Also, when this golf club was subjected to a field test with a swing robot at a head speed of 40 m / sec, it was confirmed that the ball was falling in a range of several meters at the landing point 200 m away from the tee shot point. It was.
Also in the test by the tester, scratches generated on the golf club head usually appear in the titanium alloy, and the feel of the hitting sound was closer to that of a golf club head made of a metal material.
In other words, the golf club head of the present embodiment has a very small hitting curve compared to the conventional one, no reduction in flight distance due to this, and the performance close to that of a titanium alloy golf club head in hitting sound and scratch resistance. It was something that had both.
When the golf club head after the test was cut and observed in cross section, as shown in FIG. 15, the thickness of the adhesive layer gradually increased inward from the edge of the fiber reinforced resin material member at the outer joint portion. An increase was confirmed. In the cross section of the outer joint portion, the thickness at the thinnest part of the adhesive layer was 0.1 mm, and the thickness at the thickest part was 0.2 mm.

(Example 2)
The golf club head was molded in the same manner as in Example 1 except that the material in the form of a film was FM73M (product name, shear bonding strength 30 MPa, thickness 0.1 mm) manufactured by Cytec Fiberlight. Got a golf club head.
In an endurance test with a head speed of 48 m / sec, it was found that sufficient strength was obtained.
When the golf club head after the test was cut and observed in cross section, as shown in FIG. 15, the thickness of the adhesive layer gradually increased inward from the edge of the fiber reinforced resin material member at the outer joint portion. An increase was confirmed. In the cross section of the outer joint portion, the thickness at the thinnest part of the adhesive layer was 0.1 mm, and the thickness at the thickest part was 0.2 mm.

(Comparative Example 1)
The golf club head was molded in the same manner as in Example 1 except that EPC030-320 (product name, shear bond strength 10 MPa, thickness 0.02 mm) manufactured by Nitto Boseki Co., Ltd. was used as the film-form adhesive. Got a golf club head.
In the durability test at a head speed of 48 m / second, it was found that peeling occurred on the joint surface between the titanium member and the fiber reinforced resin material member, and there was a problem in durability.
When the golf club head after the test was cut and observed in cross section, as shown in FIG. 15, the thickness of the adhesive layer gradually increased inward from the edge of the fiber reinforced resin material member at the outer joint portion. It was confirmed that the thickness increased , but in the cross section of the outer joint portion, the thickness at the thinnest part of the adhesive layer was 0.01 mm, and the thickness at the thickest part was 0.03 mm.

(Comparative Example 2)
The golf club head was molded in the same manner as in Example 1 except that the belt-shaped prepreg was not laminated on the area constituting the outer joint portion of the inner surface of the intermediate material (laminated four sheets) to obtain a golf club head. .
From the appearance, it was confirmed that the adhesive layer was exposed thickly at the end of the face crown. After the coating, in a durability test with a head speed of 48 m / sec, it was found that cracks occurred at the joint between the titanium member and the fiber reinforced resin material member, and there was a problem in durability.
When the golf club head after the test was cut and observed in cross section, the thickness of the adhesive layer in the outer joint portion was such that the end edge portion of the fiber reinforced resin material member was the same as the end edge portion of the inner metal member. It was confirmed that the thickness was thicker than the joined part.

1 is a front view showing a first embodiment of a golf club head of the present invention. 1 is a top view showing a first embodiment of a golf club head of the present invention. 1 is a right side view showing a first embodiment of a golf club head of the present invention. 1 is a bottom view showing a first embodiment of a golf club head of the present invention. 1 is a left side view showing a golf club head according to a first embodiment of the present invention. 1 is a cross-sectional view showing a first embodiment of a golf club head of the present invention. It is a front view which shows 2nd Embodiment of the golf club head of this invention. It is a top view which shows 2nd Embodiment of the golf club head of this invention. It is a right view which shows 2nd Embodiment of the golf club head of this invention. It is a bottom view which shows 2nd Embodiment of the golf club head of this invention. It is a left view which shows 2nd Embodiment of the golf club head of this invention. It is sectional drawing which expands and shows the example of the junction part concerning the golf club head of this invention. It is sectional drawing which expands and shows the example of the junction part concerning the golf club head of this invention. It is sectional drawing which expands and shows the example of the junction part concerning the golf club head of this invention. It is sectional drawing which expands and shows the example of the junction part concerning the golf club head of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Face 2 Sole 3 Crown 4 Neck 11, 21 Metal material member 12, 22 Fiber reinforced resin material member 13, 14 Adhesive layer 15 Outer joint 16 Inner joint

Claims (3)

A hollow golf club head having a joint in which an edge portion of a fiber reinforced resin material member is bonded and integrated to the outside of a metal material member via an adhesive layer,
The adhesive layer has a thickness of 0.05 to 1 mm;
The thickness of the adhesive layer in the joint is increased inward from the edge of the fiber reinforced resin material member , and the thickness at the thinnest part is 0.05 to 0.5 mm. A golf club head. The fiber reinforced resin material member is a laminate of sheet materials,
The golf club head according to claim 1, wherein the number of laminated sheet materials at the joint portion increases from the inside to the edge of the fiber reinforced resin material member.   The fiber reinforced resin material member is a laminate of sheet materials, and the fiber content in the fiber reinforced resin material member at the joint increases from the inside of the fiber reinforced resin material member toward the edge. The golf club head according to claim 1.

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