JP2022063703A - Golf club head - Google Patents

Abstract

To provide a golf club head that can sufficiently enhance the strength and repulsion performance of a face part while reducing the weight of the face part.SOLUTION: A golf club head 1 according to an embodiment of the present invention comprises a hollow head body 10 comprising a face part 2. The face part 2 comprises a repulsion region 2a in which at least a first layer 11 and a second layer 12 are stacked. The first layer 11 includes a first resin matrix, and a plurality of first fibers having a density of 2.0 g/cm3 or lower, a tensile strength of 4.0 GP or higher, and a tensile elasticity modulus of 200 GPa or higher. The second layer 12 includes a second resin matrix, and a plurality of second fibers having a breaking elongation of 3.0% or higher, and a tensile strength of 2.5 GPa or higher. The second layer 12 is located at a foremost surface or a backmost surface of the face part 2. The ratio of the average thickness of the second layer 12 to the average thickness of the repulsion region 2a is 0.1 or higher and 0.2 or lower.SELECTED DRAWING: Figure 2

Description

The present invention relates to a golf club head.

A wood-type golf club head having a hollow head body is desired to be lightweight and have sufficient strength. Further, it is desired that the face portion of the golf club head has a large repulsive performance so as to increase the flight distance of the hit ball.

From this point of view, by reducing the average crystal grain size of the back side portion of the face center in the metal wood type golf club head, the strength of the back side portion of the face center is improved and the face portion is thinned. It has been proposed to improve the repulsive performance of the head (see JP-A-2003-144591).

Japanese Patent Application Laid-Open No. 2003-144591

The metal golf club head described in Patent Document 1 has a reduced average crystal grain size of a portion of the face portion where cracks are likely to occur so that a decrease in strength can be suppressed even if the face portion is thinned. be.

However, since the metal golf club head described in Patent Document 1 has improved resilience performance by thinning the face portion, there is a trade-off relationship between the strength of the face portion and the resilience performance. .. Therefore, according to the metal golf club head described in Patent Document 1, the repulsion performance can only be improved within an allowable range of thinning of the face portion. Further, since the metal golf club head described in Patent Document 1 increases the strength of the portion where tensile stress is likely to be applied at the time of impact of the hit ball, the bending of the face portion at the time of impact of the hit ball is rather hindered. There is a risk.

The present invention has been made based on such circumstances, and the subject of the present invention is golf capable of sufficiently increasing the strength and resilience performance of the face portion while reducing the weight of the face portion. To provide a club head.

The golf club head according to one aspect of the present invention is a golf club head including a hollow head body having a face portion, and the face portion has a repulsive region in which at least a first layer and a second layer are laminated. The first layer includes a first resin matrix and a plurality of first fibers having a density of 2.0 g / cm ³ or less, a tensile strength of 4.0 GPa or more, and a tensile elastic modulus of 200 GPa or more. Contains a second resin matrix and a plurality of second fibers having a breaking elongation of 3.0% or more and a tensile strength of 2.5 GPa or more, and the second layer is located on the foremost surface or the back surface of the face portion. The ratio of the average thickness of the second layer to the average thickness of the repulsion region is 0.1 or more and 0.2 or less.

The breaking elongation of the first fiber is BE1 [GPa], the tensile strength is TS1 [GPa], the density is D1 [g / cm ³ ], the tensile elastic modulus is TM1 [GPa], and the breaking elongation of the second fiber is BE2. When [GPa], the tensile strength is TS2 [GPa], the density is D2 [g / cm ³ ], and the tensile elastic modulus is TM2 [GPa], the following formulas 1 to 4 may be satisfied.
BE1 <BE2 ・ ・ ・ 1
TS1> TS2 ・ ・ ・ 2
D1 <D2 ・ ・ ・ 3
TM1> TM2 ・ ・ ・ 4

It is preferable that the tensile elastic modulus of the first fiber is 2.5 times or more the tensile elastic modulus of the second fiber, and the breaking elongation of the second fiber is twice or more the breaking elongation of the first fiber. ..

The repulsion region further includes a third layer laminated on the surface of the first layer opposite to the second layer, and the third layer has a third resin matrix and a breaking elongation of 3.0%. As described above, it contains a plurality of third fibers having a tensile strength of 2.5 GPa or more, the second layer is located on the backmost surface of the face portion, and the third layer is located on the frontmost surface of the face portion. The ratio of the average thickness of the third layer to the average thickness of the repulsion region is preferably 0.1 or more and 0.2 or less.

It is preferable that the average thickness of the second layer is equal to or larger than the average thickness of the third layer.

The breaking elongation of the first fiber is BE1 [GPa], the tensile strength is TS1 [GPa], the density is D1 [g / cm ³ ], the tensile elastic modulus is TM1 [GPa], and the breaking elongation of the third fiber is BE3. When [GPa], the tensile strength is TS3 [GPa], the density is D3 [g / cm ³ ], and the tensile elastic modulus is TM3 [GPa], the following formulas 5 to 8 may be satisfied.
BE1 <BE3 ・ ・ ・ 5
TS1> TS3 ・ ・ ・ 6
D1 <D3 ・ ・ ・ 7
TM1> TM3 ・ ・ ・ 8

The repulsion region may include a projection point that projects the center of gravity of the golf club head onto the front surface of the face portion.

It is preferable that the repulsion region includes at least a circle having a radius of 10 mm centered on the projection point.

The face portion has a peripheral region continuously provided around the repulsive region, the peripheral region has a single-layer structure composed of the first layer, and a boundary between the repulsive region and the peripheral region. It is preferable that the front surfaces and the back surfaces of the portions are flush with each other.

The face portion has a peripheral region continuously provided around the repulsive region, the peripheral region has a single-layer structure composed of the first layer, and the second layer is formed in the peripheral region. On the other hand, it is also preferable that the face portion protrudes in the thickness direction.

The golf club head according to another aspect of the present invention is a golf club head including a hollow head body having a face portion, wherein the face portion is a glass fiber reinforced plastic layer on both sides of a carbon fiber reinforced plastic layer. Has a laminated repulsive region.

In the present invention, the "front surface" means the surface on the side to be hit, and the "back surface" means the surface on the opposite side. "Tensile strength", "tensile modulus of elasticity", and "elongation at break" mean values obtained in accordance with JIS R7606: 2000. The "average thickness" means the average value of the thickness of any 10 points.

In the golf club head according to one aspect of the present invention, a second layer having excellent flexibility is arranged on the front surface or the back surface of the face portion where stress is likely to be applied at the time of impact of a hit ball. In the golf club head, the second layer is laminated on the first layer which is lightweight and has high strength, and the ratio of the average thickness of the second layer to the average thickness of the repulsion region is 0.1 or more. By setting the value to 2 or less, the strength and repulsion performance of the face portion can be sufficiently increased while reducing the weight of the face portion.

FIG. 1 is a schematic front view showing a golf club including a golf club head according to an embodiment of the present invention. FIG. 2 is a sectional view taken along line II-II of the golf club head of FIG. FIG. 3 is a partially enlarged view of the face portion of the golf club head of FIG. FIG. 4 is a schematic view showing the bending of the face portion at the time of impact of a hit ball. FIG. 5 is a schematic plan view showing the orientation direction of the first fiber of the first layer of the golf club head of FIG. 1. FIG. 6 is a schematic plan view showing the orientation direction of the second fiber of the second layer of the golf club head of FIG. 1. FIG. 7 is a cross-sectional view corresponding to FIG. 2 of a golf club head according to an embodiment different from that of the golf club head of FIG. FIG. 8 is a partially enlarged view of the face portion of the golf club head of FIG. 7. FIG. 9 is a schematic front view showing a golf club head according to an embodiment different from that of the golf club heads of FIGS. 1 and 7. FIG. 10 is a schematic cross-sectional view showing an example of a boundary portion between the repulsive region and the peripheral region of the golf club head of FIG. FIG. 11 is a schematic cross-sectional view showing a modified example of the boundary portion between the repulsive region and the peripheral region of the golf club head of FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. Regarding the numerical values described in the present specification, it is possible to arbitrarily combine the described upper limit value and the lower limit value. In the present specification, it is assumed that the numerical range from the upper limit value to the lower limit value that can be combined is described as a suitable range.

[First Embodiment]
<Golf club head>
As shown in FIG. 1, the golf club head 1 includes a hollow head body 10. The head body 10 is formed from a face portion 2, a crown portion 3 extending rearward from the upper edge of the face portion 2, a sole portion 4 extending rearward from the lower edge of the face portion 2, and a pair of left and right side edges of the face portion 2. A side portion 5 extending rearwardly and arranged between the crown portion 3 and the sole portion 4 is provided. The golf club head 1 is a wood type golf club head. The front surface of the face portion 2 constitutes the hitting surface of the golf club head 1.

(Face part)
As shown in FIGS. 2 and 3, the face portion 2 has a repulsion region 2a in which at least the first layer 11 and the second layer 12 are laminated. The repulsion region 2a has a first layer 11, a second layer 12 laminated on the first layer 11, and a third layer 13 laminated on the surface of the first layer 11 opposite to the second layer 12. .. The second layer 12 is located on the backmost surface of the face portion 2. The third layer 13 is located on the foremost surface of the face portion 2. The repulsion region 2a is a three-layer structure in which the second layer 12, the first layer 11, and the third layer 13 are laminated in this order from the back surface side to the front surface side.

In the repulsion region 2a, the required strength is maintained and the weight of the face portion 2 is reduced, while the repulsive force of the face portion 2 is increased to increase the flight distance of the hit ball. The function of the repulsion region 2a will be described with reference to FIG.

From the viewpoint of increasing the repulsive force of the face portion 2, it is preferable to improve the flexibility of the face portion 2. However, there is usually a trade-off relationship between the improvement of the flexibility of the face portion 2 and the strength of the face portion 2. Therefore, it is required to improve the flexibility of the face portion 2 within a range in which the face portion 2 can maintain the required strength. From this point of view, the present inventor has diligently studied a configuration that effectively enhances the flexibility of the face portion 2 while maintaining the strength of the face portion 2. As shown in FIG. 4, the present inventor applies compressive stress to the hitting portion P1 on the front side of the face portion 2 when the hitting ball B is impacted by the face portion 2, and the hitting portion P1 of the face portion 2 Attention was paid to the fact that tensile stress is applied to the back surface side portion P2 facing the surface. Further, the present inventor has focused on the formation of an intermediate portion P3 in the face portion 2 between the striking portion P1 and the back surface side portion P2, to which stress is relatively difficult to be applied. As a result, the present inventor makes the portion where stress is hard to be applied at the time of impact of the hit ball B bear the function of reducing the weight and improving the strength of the face portion 2, and causes the portion where stress is easily applied to bear the function of improving the flexibility. Therefore, it was found that the repulsive force of the face portion 2 can be increased and the flight distance of the hit ball can be increased while maintaining the strength of the face portion 2 and reducing the weight of the face portion 2. That is, in the repulsion region 2a, the first layer 11 is a layer that mainly contributes to the weight reduction and the improvement of the strength of the face portion 2, and the second layer 12 and the third layer 13 are mainly the flexibility of the face portion 2. It is a layer that contributes to improvement.

The repulsion region 2a includes a region that comes into contact with the hit ball at the time of impact of the hit ball. In FIGS. 1 to 3, the repulsion region 2a is provided over the entire region of the face portion 2. That is, the face portion 2 is composed of the repulsion region 2a.

(1st layer)
As shown in FIG. 5, the first layer 11 includes a first resin matrix 11a and a plurality of first fibers 11b. Examples of the first fiber 11b include carbon fiber. The first layer 11 is, for example, a carbon fiber reinforced plastic layer (CFRP layer) containing a plurality of carbon fibers in the first resin matrix 11a. Examples of the main component of the first resin matrix 11a include thermosetting resins such as epoxy resins and unsaturated polyesters, and thermoplastic resins such as polyolefins and polyamides. Examples of the first fiber 11b include PAN-based and pitch-based fibers. The first layer 11 may contain fibers other than the first fiber 11b. However, from the viewpoint of controlling the physical properties of the first layer 11, it is preferable that the first layer 11 does not contain any fibers other than the first fiber 11b.

The first fiber 11b has a density of 2.0 g / cm ³ or less, a tensile strength (tensile strength in the longitudinal direction) of 4.0 GPa or more, and a tensile elastic modulus (tensile modulus in the longitudinal direction) of 200 GPa or more. When the density of the first fiber 11b is not more than the upper limit and the tensile strength and the tensile elastic modulus are not more than the lower limit, the weight reduction of the face portion 2 is promoted and the strength of the repulsion region 2a is increased.

The upper limit of the density of the first fiber 11b is 2.0 g / cm ³ as described above, preferably 1.9 g / cm ³ . If the density exceeds the upper limit, the weight reduction of the face portion 2 may not be sufficiently promoted. On the other hand, the lower limit of the density is not particularly limited, but is preferably 1.3 g / cm ³ and 1.5 g / cm from the viewpoint of suppressing the strength of the first fiber 11b from becoming insufficient. cm ³ is more preferred.

As described above, the lower limit of the tensile strength of the first fiber 11b is 4.0 GPa, more preferably 4.5 GPa. If the tensile strength does not reach the lower limit, the durability against the impact of a hit ball or the like may be insufficient. On the other hand, the upper limit of the tensile strength is not particularly limited, but 10.0 GPa is preferable, and 8.0 GPa is more preferable, from the viewpoint that the density and the tensile elastic modulus can be easily controlled within a desired range.

The lower limit of the tensile elastic modulus of the first fiber 11b is 200 GPa as described above, preferably 240 GPa. If the tensile modulus does not reach the lower limit, the durability against the impact of a hit ball may be insufficient. On the other hand, the upper limit of the tensile elastic modulus is not particularly limited, but is preferably 400 GPa and more preferably 350 GPa from the viewpoint of suppressing insufficient flexibility of the repulsive region 2a.

The lower limit of the breaking elongation of the first fiber 11b is preferably 1.2%, more preferably 1.5%. On the other hand, the upper limit of the elongation at break is preferably 3.0%, more preferably 2.5%. If the breaking elongation does not reach the lower limit, the durability against the impact of a hit ball or the like may be insufficient. On the contrary, if the breaking elongation exceeds the upper limit, the strength of the first layer 11 may be insufficient.

As shown in FIG. 5, it is preferable that the plurality of first fibers 11b are arranged so as to intersect each other in a plan view. More specifically, it is preferable that the plurality of first fibers 11b are arranged in a grid pattern in a plan view. According to this configuration, while increasing the strength of the repulsion region 2a, it is easy to suppress the anisotropy of the deflection of the repulsion region 2a and increase the repulsion force.

(2nd layer)
As shown in FIG. 6, the second layer 12 includes a second resin matrix 12a and a plurality of second fibers 12b. Examples of the second fiber 12b include glass fiber. The second layer 12 is, for example, a glass fiber reinforced plastic layer (GFRP layer) containing a plurality of glass fibers in the second resin matrix 12a. Examples of the main component of the second resin matrix 12a include thermosetting resins such as epoxy resins and unsaturated polyesters, and thermoplastic resins such as polyolefins and polyamides. The second layer 12 may contain fibers other than the second fiber 12b. However, from the viewpoint of controlling the physical properties of the second layer 12, it is preferable that the second layer 12 does not contain any fibers other than the second fiber 12b.

The second fiber 12b has a breaking elongation of 3.0% or more and a tensile strength (tensile strength in the longitudinal direction) of 2.5 GPa or more. The second fiber 12b enhances the flexibility of the repulsion region 2a by having the breaking elongation and the tensile strength at least the above lower limit.

As described above, the lower limit of the breaking elongation of the second fiber 12b is 3.0%, more preferably 4.0%. If the breaking elongation is less than the lower limit, the flexibility of the repulsion region 2a may not be sufficiently improved. On the other hand, the upper limit of the elongation at break is not particularly limited, but is preferably 6.5% and more preferably 5.5% from the viewpoint of easily increasing the repulsive force due to bending.

The lower limit of the tensile strength of the second fiber 12b is 2.5 GPa as described above, preferably 2.8 GPa. If the tensile strength does not reach the lower limit, the durability against the impact of a hit ball or the like may be insufficient. On the other hand, the upper limit of the tensile strength is not particularly limited, but is preferably 4.0 GPa and more preferably 3.5 GPa from the viewpoint of easily controlling the elongation at break within a desired range.

As the upper limit of the density of the second fiber 12b, 3.5 g / cm ³ is preferable, and 3.0 g / cm ³ is more preferable. If the density exceeds the upper limit, the weight reduction of the face portion 2 may not be sufficiently promoted. On the other hand, the lower limit of the density is not particularly limited, but is preferably 1.5 g / cm ³ and 2.0 g / cm from the viewpoint of suppressing the strength of the second fiber 12b from becoming insufficient. cm ³ is more preferred.

As the lower limit of the tensile elastic modulus of the second fiber 12b, 40 GPa is preferable, and 60 GPa is more preferable. On the other hand, as the upper limit of the tensile elastic modulus, 120 GPa is preferable, and 100 GPa is more preferable. If the tensile modulus does not reach the lower limit, the durability against the impact of a hit ball may be insufficient. On the contrary, if the tensile elastic modulus exceeds the upper limit, the flexibility of the repulsive region 2a may be insufficient.

The breaking elongation of the first fiber 11b is BE1 [GPa], the tensile strength is TS1 [GPa], the density is D1 [g / cm ³ ], the tensile elasticity is TM1 [GPa], and the breaking elongation of the second fiber 12b is BE2. When [GPa], the tensile strength is TS2 [GPa], the density is D2 [g / cm ³ ], and the tensile elasticity is TM2 [GPa], it is preferable to satisfy the following formulas 1 to 4.
BE1 <BE2 ・ ・ ・ 1
TS1> TS2 ・ ・ ・ 2
D1 <D2 ・ ・ ・ 3
TM1> TM2 ・ ・ ・ 4

By satisfying the above formulas 1 to 4, the golf club head 1 can easily increase the repulsive force of the repulsive region 2a by the second layer 12 while reducing the weight and improving the strength of the face portion 2 by the first layer 11. .. As a result, it is easy to increase the flight distance of the hit ball while maintaining the strength of the face portion 2 and reducing the weight of the face portion 2.

The tensile elastic modulus TM1 of the first fiber 11b is preferably 2.5 times or more, more preferably 3.0 times or more, the tensile elastic modulus TM2 of the second fiber 12b. Further, the breaking elongation BE2 of the second fiber 12b is preferably twice or more, more preferably 2.1 times or more, of the breaking elongation BE1 of the first fiber 11b. By controlling the tensile elastic modulus and the elongation at break of the first fiber 11b and the second fiber 12b in this way, the strength of the face portion 2 is improved by the first layer 11, and the repulsion region 2a is formed by the second layer 12. It is easy to increase the repulsive force of. As a result, it is easy to increase the flight distance of the hit ball while maintaining the strength of the face portion 2.

As shown in FIG. 6, it is preferable that the plurality of second fibers 12b are arranged so as to intersect each other in a plan view. More specifically, it is preferable that the plurality of second fibers 12b are arranged in a grid pattern in a plan view. According to this configuration, while increasing the strength of the repulsion region 2a, it is easy to suppress the anisotropy of the deflection of the repulsion region 2a and increase the repulsion force.

As shown in FIG. 3, the lower limit of the ratio (T2 / T1) of the average thickness T2 of the second layer 12 to the average thickness T1 of the repulsion region 2a is 0.1, preferably 0.12. On the other hand, the upper limit of the average thickness ratio (T2 / T1) is 0.2, preferably 0.18. If the ratio of the average thickness (T2 / T1) is not less than the lower limit, the flexibility of the portion where stress is likely to be applied at the time of impact of the hit ball cannot be sufficiently increased, and the flight distance of the hit ball is sufficiently increased. May not be possible. On the contrary, if the ratio of the average thickness (T2 / T1) exceeds the upper limit, the strength of the face portion 2 may be insufficient.

The average thickness T2 of the second layer 12 is preferably equal to or higher than the average thickness T3 of the third layer 13. At the time of impact of the hit ball, the face portion 2 bends in a convex bowl shape from the front side to the back side, so that the back side portion tends to have a larger amount of deformation. Therefore, by setting the average thickness T2 of the second layer 12 to be equal to or larger than the average thickness T3 of the third layer 13, the repulsive force of the repulsive region 2a can be easily increased.

(Third layer)
The third layer 13 includes a third resin matrix and a plurality of third fibers. Examples of the main component of the third resin matrix include the above-mentioned synthetic resin exemplified as the main component of the second resin matrix 12a. Examples of the third fiber include glass fiber. The main component of the third resin matrix may be different from the main component of the second resin matrix 12a, and the third fiber may be different from the second fiber 12b. However, the main component of the third resin matrix is preferably the same as the main component of the second resin matrix 12a, and the third fiber is preferably the same as the second fiber 12b. The third layer 13 is, for example, a GFRP layer containing a plurality of glass fibers in the third resin matrix. The third layer 13 may contain fibers other than the third fiber. However, from the viewpoint of controlling the physical properties of the third layer 13, it is preferable that the third layer 13 does not contain fibers other than the third fiber.

The third fiber has a breaking elongation of 3.0% or more and a tensile strength (tensile strength in the longitudinal direction) of 2.5 GPa or more. As shown in FIG. 3, the lower limit of the ratio (T3 / T1) of the average thickness T3 of the third layer 13 to the average thickness T1 of the repulsion region 2a is preferably 0.1, more preferably 0.12. On the other hand, as the upper limit of the average thickness ratio (T3 / T1), 0.2 is preferable, and 0.18 is more preferable. In the repulsion region 2a, the second layer 12 is located on the backmost surface of the face portion 2, the third layer 13 is located on the frontmost surface of the face portion 2, and the second layer 12 is located between the second layer 12 and the third layer 13. By arranging the 1st layer 11, the strength of the face portion 2 is maintained, the weight of the face portion 2 is reduced, and the flexibility of the face portion 2 is effectively increased to facilitate the flight distance of the hit ball. You can definitely make it bigger.

The breaking elongation of the third fiber can be in the same range as the breaking elongation of the second fiber 12b. The tensile strength of the third fiber can be in the same range as the tensile strength of the second fiber 12b. The density of the third fiber can be in the same range as the density of the second fiber 12b. The tensile elastic modulus of the third fiber can be in the same range as the tensile elastic modulus of the second fiber 12b.

The breaking elongation of the first fiber 11b is BE1 [GPa], the tensile strength is TS1 [GPa], the density is D1 [g / cm ³ ], the tensile elasticity is TM1 [GPa], and the breaking elongation of the third fiber is BE3. When [GPa], the tensile strength is TS3 [GPa], the density is D3 [g / cm ³ ], and the tensile elasticity is TM3 [GPa], it is preferable to satisfy the following formulas 5 to 8.
BE1 <BE3 ・ ・ ・ 5
TS1> TS3 ・ ・ ・ 6
D1 <D3 ・ ・ ・ 7
TM1> TM3 ・ ・ ・ 8

By satisfying the above formulas 5 to 8, the golf club head 1 can easily increase the repulsive force of the repulsive region 2a by the third layer 13 while reducing the weight and improving the strength of the face portion 2 by the first layer 11. .. As a result, it is easy to increase the flight distance of the hit ball while maintaining the strength of the face portion 2 and reducing the weight of the face portion 2.

The tensile elastic modulus TM1 of the first fiber 11b is preferably 2.5 times or more, more preferably 3.0 times or more, the tensile elastic modulus TM3 of the third fiber. Further, the breaking elongation BE3 of the third fiber is preferably twice or more, more preferably 2.1 times or more, more preferably 2.1 times or more the breaking elongation BE1 of the first fiber 11b.

It is preferable that the plurality of third fibers are arranged so as to intersect each other in a plan view. More specifically, it is preferable that the plurality of third fibers are arranged in a grid pattern in a plan view.

The first layer 11 is preferably a CFRP layer, and the second layer 12 and the third layer 13 are preferably GFRP layers. That is, it is preferable that the face portion 2 has a repulsive region 2a in which GFRP layers are laminated on both sides of the CFRP layer. Further, in this configuration, it is preferable that the GFRP layer is located on the frontmost surface and the backmost surface of the face portion 2. In the golf club head 1, the first layer 11 is a CFRP layer, and the second layer 12 and the third layer 13 are GFRP layers, so that the breaking elongation, tensile strength, density, tensile elastic modulus, etc. of each layer can be easily improved. And it can be controlled reliably. As a result, the golf club head 1 tends to increase the flight distance of the hit ball while maintaining the strength of the face portion 2 and reducing the weight of the face portion 2.

<Advantage>
The golf club head 1 has a second layer 12 having excellent flexibility arranged on the backmost surface of the face portion 2 where stress is likely to be applied at the time of impact of a hit ball. In the golf club head 1, the second layer 12 is laminated on the first layer 11 which is lightweight and has high strength, and the ratio of the average thickness T2 of the second layer 12 to the average thickness T1 of the repulsion region 2a (T2 /). By setting T1) to 0.1 or more and 0.2 or less, the strength and resilience performance of the face portion 2 can be sufficiently increased while reducing the weight of the face portion 2.

[Second Embodiment]
<Golf club head>
The golf club head 21 of FIG. 7 includes a hollow head body 30 having a face portion 32. The face portion 32 has a repulsion region 32a in which the first layer 11 and the second layer 12 are laminated. As shown in FIG. 8, the repulsion region 32a is a two-layer structure of the first layer 11 and the second layer 12. The second layer 12 is located on the backmost surface of the face portion 32. The ratio (T2 / T1) of the average thickness T2 of the second layer 12 to the average thickness T1 of the repulsion region 32a is the ratio of the second layer 12 to the average thickness T1 of the repulsion region 2a of the golf club head 1 of FIG. It can be the same as the ratio of the average thickness T2.

The golf club head 21 can have the same configuration as the golf club head 1 of FIG. 1 except that the repulsion region 32a does not have a third layer laminated on the front surface of the first layer 11. That is, the specific configuration of the first layer 11 can be the same as that of the first layer 11 of the golf club head 1 of FIG. 1, and the specific configuration of the second layer 12 is that of the golf club head 1 of FIG. It can be the same as the second layer 12. In the golf club head 21, it is preferable that the first layer 11 is a CFRP layer and the second layer 12 is a GFRP layer.

<Advantage>
In the golf club head 21, the repulsion region 32a is a laminated body of the first layer 11 and the second layer 12. Since the second layer 12 of the golf club head 21 is located at the rearmost surface of the face portion 32 where stress is likely to be applied at the time of impact of a hit ball, the weight of the face portion 32 is reduced and the face portion 32 is divided. The strength and resilience performance can be sufficiently enhanced.

[Third Embodiment]
<Golf club head>
The golf club head 41 of FIG. 9 has a face portion 52 having a repulsion region 52a and a peripheral region 52b continuously provided around the repulsion region 52a. The repulsion region 52a can be a laminated body of the first layer 11 and the second layer 12, similarly to the repulsion region 32a of the golf club head 21 of FIG. 7. Further, the repulsion region 52a can be a three-layer structure of the first layer 11, the second layer 12, and the third layer 13, similarly to the repulsion region 2a of the golf club head 1 of FIG. The peripheral region 52b can have a single-phase structure composed of the first layer 11.

The repulsion region 52a includes a projection point G in which the center of gravity of the golf club head 41 is projected onto the front surface of the face portion 52. By providing the repulsive region 52a so that the golf club head 41 can easily include the hitting portion of the hit ball, the repulsive force of the face portion 52 can be increased and the flight distance of the hit ball can be increased. Further, the golf club head 41 is likely to promote weight reduction of the face portion 52 by providing a peripheral region 52b around the repulsion region 52a.

The repulsion region 52a preferably includes a circle C having a radius of at least 10 mm centered on the projection point G. More specifically, it is preferable that the repulsion region 52a includes a virtual circle having a radius of 10 mm drawn on the front surface of the face portion 52 with the projection point G as the center. The contact area with the hit ball on the front surface of the face portion 52 at the time of impact of the hit ball is usually a circle with a radius of about 10 mm. Therefore, since the repulsion region 52a includes the circle C, the flexibility of the contact portion with the hit ball can be increased and the flight distance of the hit ball can be easily and surely increased.

As shown in FIG. 10, it is preferable that the front surfaces and the back surfaces of the boundary portion between the repulsion region 52a and the peripheral region 52b are flush with each other. According to this configuration, it is easy to reduce the weight of the face portion 52 by reducing the thickness of the repulsion region 52a.

On the other hand, as shown in FIG. 11, it is also preferable that the second layer 12 projects in the thickness direction of the face portion 52 with respect to the peripheral region 52b. According to this configuration, the strength of the face portion 52 can be easily and surely increased. Further, by using a relatively lightweight CFRP layer as the first layer 11, it is possible to suppress an increase in the weight of the face portion 52.

<Advantage>
The golf club head 41 can sufficiently increase the strength and repulsion performance of the face portion 52 while reducing the weight of the face portion 52.

[Other embodiments]
The embodiments do not limit the configuration of the present invention. Accordingly, the embodiments may be omitted, replaced or added to components of each of the embodiments based on the description and common sense of the art, all of which are construed as belonging to the scope of the present invention. Should be.

For example, when the repulsion region is a two-layer structure of the first layer and the second layer, the second layer may be located on the foremost surface of the face portion. Since the two layers of the golf club head are located on the foremost surface of the face portion, the flexibility of the portion where compressive stress is likely to be applied at the time of impact of the hit ball can be increased, and the flight distance of the hit ball can be increased.

As long as it has a predetermined elongation at break and tensile strength, the same fiber as the first fiber can be used as the second fiber and the third fiber.

When the repulsion region is a three-layer structure consisting of the first layer, the second layer located on the backmost surface of the face portion, and the third layer located on the frontmost surface of the face portion, the second layer. It is also possible to make the average thickness of the layers smaller than the average thickness of the third layer. Also with this configuration, it is possible to sufficiently increase the strength and resilience performance of the face portion while reducing the weight of the face portion.

As described above, the golf club head according to one aspect of the present invention is suitable for increasing the flight distance of a hit ball while reducing the weight and maintaining the required strength.

1, 21, 41 Golf club head 2, 32, 52 Face part 2a, 32a, 52a Repulsion area 3 Crown part 4 Sole part 5 Side part 10, 30 Head body 11 First layer 11a First resin matrix 11b First fiber 12 2nd layer 12a 2nd resin matrix 12b 2nd fiber 13 3rd layer 52b Peripheral area B Hitting ball C Circle with a radius of 10 mm drawn on the front surface of the face portion G Projection point P1 in which the center of gravity of the golf club head is projected onto the front surface of the face portion. Hitting part P2 Back side part P3 Intermediate part T1 Average thickness of repulsion area T2 Average thickness of second layer T3 Average thickness of third layer

Claims (11)

A golf club head having a hollow head body having a face portion.
The face portion has a repulsive region in which at least the first layer and the second layer are laminated.
The first layer contains a first resin matrix and a plurality of first fibers having a density of 2.0 g / cm ³ or less, a tensile strength of 4.0 GPa or more, and a tensile elastic modulus of 200 GPa or more.
The second layer contains a second resin matrix and a plurality of second fibers having a breaking elongation of 3.0% or more and a tensile strength of 2.5 GPa or more.
The second layer is located on the frontmost surface or the backmost surface of the face portion, and the ratio of the average thickness of the second layer to the average thickness of the repulsion region is 0.1 or more and 0.2 or less. Golf club head. The breaking elongation of the first fiber is BE1 [GPa], the tensile strength is TS1 [GPa], the density is D1 [g / cm ³ ], the tensile elasticity is TM1 [GPa], and the breaking elongation of the second fiber is BE2. The golf club head according to claim 1, wherein when [GPa], the tensile strength is TS2 [GPa], the density is D2 [g / cm ³ ], and the tensile elasticity is TM2 [GPa], the following formulas 1 to 4 are satisfied. ..
BE1 <BE2 ・ ・ ・ 1
TS1> TS2 ・ ・ ・ 2
D1 <D2 ・ ・ ・ 3
TM1> TM2 ・ ・ ・ 4 A claim that the tensile elastic modulus of the first fiber is 2.5 times or more the tensile elastic modulus of the second fiber, and the breaking elongation of the second fiber is twice or more the breaking elongation of the first fiber. 1 or the golf club head according to claim 2. The repulsion region further comprises a third layer laminated on the surface of the first layer opposite to the second layer.
The third layer contains a third resin matrix and a plurality of third fibers having a breaking elongation of 3.0% or more and a tensile strength of 2.5 GPa or more.
The second layer is located on the backmost surface of the face portion, and the third layer is located on the frontmost surface of the face portion, and the average thickness of the third layer is relative to the average thickness of the repulsion region. The golf club head according to claim 1, claim 2 or claim 3, wherein the ratio is 0.1 or more and 0.2 or less. The golf club head according to claim 4, wherein the average thickness of the second layer is equal to or larger than the average thickness of the third layer. The breaking elongation of the first fiber is BE1 [GPa], the tensile strength is TS1 [GPa], the density is D1 [g / cm ³ ], the tensile elasticity is TM1 [GPa], and the breaking elongation of the third fiber is BE3. [GPa], claim 4 or claim 5 satisfying the following formulas 5 to 8 when the tensile strength is TS3 [GPa], the density is D3 [g / cm ³ ], and the tensile elasticity is TM3 [GPa]. Golf club head.
BE1 <BE3 ・ ・ ・ 5
TS1> TS3 ・ ・ ・ 6
D1 <D3 ・ ・ ・ 7
TM1> TM3 ・ ・ ・ 8 The golf club head according to any one of claims 1 to 6, wherein the repulsion region includes a projection point in which the center of gravity of the golf club head is projected onto the front surface of the face portion. The golf club head according to claim 7, wherein the repulsion region includes a circle having a radius of at least 10 mm centered on the projection point. The face portion has a peripheral region continuously provided around the repulsive region.
The peripheral region is a single-layer structure composed of the first layer.
The golf club head according to any one of claims 1 to 8, wherein the front surfaces and the back surfaces of the boundary portion between the repulsion region and the peripheral region are flush with each other. The face portion has a peripheral region continuously provided around the repulsive region.
The peripheral region is a single-layer structure composed of the first layer.
The golf club head according to any one of claims 1 to 8, wherein the second layer projects from the peripheral region in the thickness direction of the face portion. A golf club head having a hollow head body having a face portion.
A golf club head in which the face portion has a repulsive region in which glass fiber reinforced plastic layers are laminated on both sides of the carbon fiber reinforced plastic layer.

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