JPH06142239A - Golf club head - Google Patents

Abstract

PURPOSE:To enable a face body to elastically behave within the range of compressed deformation likely to appear due to collision with a ball, have rigidity approximately synchronized with the deformation of the ball and further to be sufficiently durable over a long term of use. CONSTITUTION:A recess 11a formed on the face section of a head body 11 is provided with a face body 13 having a double layer structure of an inner layer 14 made of a rubber type elastic body, and an outer layer 15 made of a fiber reinforced plastic with a Young's modulus larger than the inner layer 14. In this case, the external surface of the outer layer 15 is used as the face of a head. In addition, the value of the Young's modulus is changed, so that the outer layer 15 comes to have a smaller value near the Young's modulus of the inner layer 14 made of the rubber elastic body, according to an approach thereto.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a golf club head, and more particularly to a face structure which can extend a flight distance of a ball and is excellent in durability.

[0002]

2. Description of the Related Art In order to increase the initial velocity of a golf ball at the time of hitting the ball and increase the flight distance of the ball, it is important to make the coefficient of restitution between the ball and the club head as large as possible. It is desirable to deform in synchronization with the deformation of the ball. That is, when the mass of the golf ball is m _b , the mass of the club head is m _c , the rigidity of the ball is K _b, and the effective rigidity of the head face portion is K _c , the deformation of the head and the ball during collision The tuning condition of can be expressed by the following equation.

## EQU1 ## K _c = (m _c / m _b ) K _b On the other hand, E is the Young's modulus of the face body provided on the head face portion, t is its effective thickness, and A is the area in contact with the ball at the time of collision. Then,

## EQU2 ## Since E = (t / A) K _c , the Young's modulus E of the face body for satisfying the above tuning conditions must satisfy the following equation.

## EQU3 ## E = (t / A) (m _c / m _b ) K _b

In order to realize such tuning transformation,
It is necessary for the face body of the head to have rigidity that can be substantially synchronized with the ball within the range of compression deformation due to collision with the ball, and to have elastic behavior within the range of compression deformation due to collision with the ball.

An elastic body such as rubber is considered as a material satisfying such a tuning condition. For example, a face body of a head is formed by a rubber layer having a thickness T = 6.6 mm, and this rubber layer directly collides with a ball. In the case where the above-mentioned configuration is adopted, at least the Young's modulus E of the rubber is required to satisfy the above tuning condition.
Should be 5.0 × 10 ^{7 to} 8.0 × 10 ⁷ N / m ² . However, since the actual Young's modulus E of butadiene rubber is, for example, about 1.0 × 10 ^{7 to} 2.0 × 10 ⁷ N / m ² , the rubber layer alone does not satisfy the above conditions. Also,
When the ball is made to directly collide with the rubber layer, the wear resistance of the surface of the rubber layer is low, so that the face body is easily worn.

Therefore, the present applicant has fixed to the face portion of the head body a face body having a two-layer structure of an inner layer made of a rubber-like elastic body and an outer layer made of a fiber reinforced resin having a Young's modulus larger than that of the inner layer. I proposed a new golf club head. According to the face structure of the golf club head, the face body has elastic behavior within the range of compressive deformation that can occur due to collision with the ball, and has rigidity that is substantially in tune with the deformation of the ball. Is almost satisfied, and the flight distance of the ball is increased.
In addition, since the elastic body layer of this face body is protected by the fiber reinforced resin layer, the durability is improved as compared with the face body made of only an elastic body such as rubber.

[0006]

However, a large change in rigidity occurs at the interface between the fiber-reinforced resin layer using a general epoxy resin or carbon fiber or the like and the elastic body layer such as rubber. Large stress concentration is likely to occur. It is considered that such stress concentration is one of the causes for inducing interface delamination and delamination in the fiber reinforced resin layer.

Therefore, it is an object of the present invention that the face body behaves elastically within the range of compressive deformation due to the collision with the ball, and has a rigidity that is substantially in tune with the deformation of the ball, and the face body is long-term. It is an object of the present invention to provide a golf club head having durability that can be sufficiently used.

[0008]

The invention according to claim 1 is
To the face portion of the head body, a face body having a two-layer structure of an inner layer made of a rubber-like elastic body and an outer layer made of a highly rigid body having a Young's modulus larger than that of the rubber-like elastic body is fixed, and the surface of the outer layer is headed. In the golf club head having the face surface as described above, the Young's modulus of the outer layer changes in the thickness direction such that the Young's modulus of the outer layer decreases toward the inner layer and approaches the Young's modulus value of the inner layer.

According to a second aspect of the present invention, in the golf club head having the above-mentioned structure, the Young's modulus of the inner layer changes in the thickness direction so as to increase toward the outer layer.

According to a third aspect of the present invention, the head body has a three-layer structure in which a face portion of the head body is sandwiched on both sides of an inner layer made of a rubber-like elastic body with an outer layer made of a highly rigid body having a Young's modulus larger than that of the inner layer. In a golf club head having a face body fixed and one of the outer layers having a head face surface, the Young's modulus of the both outer layers becomes smaller toward the inner layer and approaches the Young's modulus value of the inner layer. It is characterized by changing to.

According to a fourth aspect of the present invention, in the golf club head having each of the above structures, the outer layer is made of a fiber-reinforced resin in which fiber layers are laminated.

[0012]

In the golf club head according to the present invention, the inner layer made of the rubber-like elastic material can exhibit elastic behavior within the range of compressive deformation due to collision with the ball. In addition, since the surface of the inner layer made of a rubber-like elastic body is covered with the outer layer made of a high-rigidity body having a Young's modulus larger than that of the elastic body, the inner layer of the elastic body has a wider range than in the case of directly colliding with the ball. This results in compressive deformation, and as a result, even if the Young's modulus E of the rubber-like elastic body itself is about 1.0 × 10 ^{7 to} 2.0 × 10 ⁷ N / m ² , the above tuning condition can be sufficiently satisfied. Become. Therefore, the coefficient of restitution with the ball is increased and the flight distance of the ball can be extended. In addition, the Young's modulus of the outer layer decreases from the outer side of the face toward the inner layer, and changes in the thickness direction so as to approach the Young's modulus value of the inner layer. The face body is less likely to be destroyed due to concentration. Therefore, the durability of the face body is enhanced.

In the golf club head according to the second aspect, the Young's modulus of the inner layer made of the rubber-like elastic body changes in the thickness direction so as to increase toward the outer layer made of the high rigidity body. It is possible to suppress the change in the rigidity of the interface between the inner layer and the outer layer to be small while suppressing the change in Young's modulus to be small.

In the golf club head of the third aspect, the outer layer of the high-rigidity body on the face side functions similarly to the outer layer of the face body of the first aspect, and the outer layer of the high-rigidity body on the other side functions as the face body. It plays the role of increasing the adhesion to the head body. The Young's modulus of the high-rigidity outer layer on both sides of the inner layer made of a rubber-like elastic body decreases as it approaches the inner layer, and changes in the thickness direction to approach the Young's modulus value of the inner layer. The change in the rigidity of the interface becomes small, and the face body is less likely to be broken due to stress concentration. Therefore, the durability of the face body is enhanced.

In the golf club head according to the present invention, since the outer layer is made of a fiber reinforced resin in which fiber layers are laminated, high rigidity can be obtained by changing the type of fibers, the arrangement density, or the resin material for each layer. The Young's modulus of the outer layer can be easily changed in the thickness direction.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. In the drawings, the same constituent members are designated by the same reference numerals, and duplicate description will be omitted.

FIGS. 1 to 4 show a first embodiment of the present invention. FIG. 1 is a partially cutaway perspective view of a golf club head, and FIG. 2 is a partially longitudinal sectional side view of a head. 3 is a partial horizontal cross-sectional plan view of the head, FIG. 4 (a) is an enlarged cross-sectional view of an essential part schematically showing the layer structure of the face body, and FIG. 4 (b) is a schematic diagram of Young's modulus E of each layer of the face body. It is a graph shown.

First, referring to FIGS. 1 and 2,
The club head 10 is integrally connected to the heel end of the head body 11 having a hollow structure, which is made of metal such as stainless steel or light alloy, or fiber reinforced resin, fiber reinforced metal, or ceramics. Neck 1
2 and a club shaft (not shown) is connected to the neck portion 12. In the recess 11a formed in the face portion of the head body 11, for example, a rubber-like elastic inner layer 14 made of a thermosetting rubber such as butadiene, and an elastic inner layer adhered to the surface of the elastic inner layer 14 are formed. Also, a face body 13 having a high-rigidity outer layer 15 having a large Young's modulus is provided so as to fill the recess 11a,
The surface of the outer layer 15 constitutes the face surface of the head 10. The face body 13 is backed up (rigidly supported) by the inner bottom wall 11b of the face portion of the head body 11.

In this embodiment, the rubber-like elastic inner layer 14 is made of butadiene rubber, and the high-rigidity outer layer 15 is made of fiber reinforced resin in which fiber layers are laminated. The preformed face body 13 can be inserted into the recess 11a of the head body 11, and the rubber-like elastic inner layer 14 can be fixed to the inner bottom surface of the recess 11a with an adhesive or the like. The face body 13 may be integrally formed with the head body 11 by integrally molding the rubber-like elastic inner layer 14 and the high-rigidity outer layer 15 in 11a.

For simplification of the description, in FIG. 4 (a), the high-rigidity outer layer 1 attached to the rubber-like elastic inner layer 14 is shown.
Although 5 is shown as a three-layer structure of the fiber reinforced resin layers 15a to 15c, it is actually preferable to have a multilayer structure. (B) of the figure schematically shows the Young's modulus E of each layer shown in the (a) of the figure. In this way, by changing the Young's modulus E of each layer of the high-rigidity outer layer 15 in the thickness direction, the Young's modulus of the high-rigidity outer layer 15 is reduced toward the rubber-like elastic inner layer 14 and the rubber-like elastic inner layer 14 is reduced. It is changed in the thickness direction so as to approach the Young's modulus value.

As a method of changing the Young's modulus of the high-rigidity outer layer 15 made of fiber reinforced resin in the thickness direction, for example, carbon fiber is used for the resin layer on the surface side and glass is used for the resin layer on the elastic body layer side. The method of changing the reinforcing fiber used for each layer to one having a different Young's modulus, such as the method of using fibers and changing the mixing ratio of carbon fiber and glass fiber for the resin layer of the intermediate layer, and the resin material of each layer has Young's modulus There is a method of changing to a different one, or a method of combining them. According to these methods, the Young's modulus of the high-rigidity outer layer 15 can be easily changed in the thickness direction.

In the golf club head constructed as described above, the rubber-like elastic inner layer 14 of the face body 13 can exhibit elastic behavior within the range of compressive deformation due to collision with the ball. Further, since the high-rigidity outer layer 15 having a Young's modulus larger than that of the elastic body layer is applied to the surface of the elastic body layer 14, the elastic body layer 14 is compressed in a wider range as compared with the case of directly colliding with the ball. It will be transformed, and as a result,
Young's modulus E of the elastic body layer itself is 1.0 × 10 ^{7 to} 2.0 × 10 ⁷ N
Even if it is about / m ² , the above tuning condition can be sufficiently satisfied. Therefore, the coefficient of restitution with the ball is increased and the flight distance of the ball can be extended. Also,
The Young's modulus of the high-rigidity outer layer 15 attached to the surface of the elastic inner layer 14 is calculated from the surface side of the face body 13 to the elastic inner layer 1
4, it becomes smaller as it approaches 4, and changes in the thickness direction so as to approach the Young's modulus value of the elastic body layer 14, so that the change in rigidity at the interface between the elastic body layer 14 and the highly rigid outer layer 15 becomes small, and the stress concentration causes The face body 13 is less likely to be destroyed. Therefore, the durability of the face body 13 is enhanced.

5 and 6 show a second embodiment of the present invention. In this embodiment, as shown in FIG.
The face body 13 provided in the recess 11a of the face portion of the head body 11 sandwiches both sides of the rubber-like elastic inner layer 14 with the high-rigidity outer layers 15 and 16 made of fiber reinforced resin.
It has a layered structure, and one outer layer 15 forms the face surface of the head 10. For simplification of explanation, FIG.
In (a), the high-rigidity outer layer 15 on the outer surface side of the face body
Is shown as a three-layer structure of the fiber reinforced resin layers 15a to 15c, and the highly rigid outer layer 16 on the inner face side of the face is shown as a two-layer structure of the fiber reinforced resin layers 16a and 16b. It is preferable that both 15 and 16 are constructed in multiple layers. Since the rubber-like elastic inner layer 14 is fixed to the inner bottom surface of the recess 11 of the head main body 11 via the high-rigidity outer layer 16, the fixing strength between the head main body 11 and the face body 13 is increased. The elastic inner layer 14 and the both high-rigidity outer layers 15 and 16 can be made of the same material as in the first embodiment.

As shown in FIG. 6B, in this second embodiment, as with the high-rigidity outer layer 15 on the front surface side of the face body 13, the Young's modulus of the high-rigidity outer layer 16 on the back surface side of the face body 13 is the same. The coefficient decreases as it approaches the rubber-like elastic body layer 14, and changes in the thickness direction so as to approach the Young's modulus value of the rubber-like elastic body layer 14, so that the rubber-like elastic body layer 14 and the high-rigidity outer layer 16 are separated from each other. It is possible to reduce the change in the rigidity of the interface and prevent layer separation and interface separation due to stress concentration.

FIG. 7 shows a modification of the rubber-like elastic inner layer 14 of the first embodiment described above. The Young's modulus of the rubber-like elastic inner layer 14 changes in the thickness direction such that it is large on the high rigidity outer layer side and small on the face inner surface side. As a method for obtaining such a Young's modulus distribution in the thickness direction, a method of mixing reinforcing fine particles, short fibers, etc. in a rubber material and changing the distribution in the thickness direction by utilizing centrifugal force during molding, It is possible to use a method of making a difference in curing temperature in the thickness direction of the rubber material during rubber molding, a method of utilizing a difference in specific gravity of the rubber material, or the like.

When the rubber-like elastic inner layer 14 having the Young's modulus changed in the thickness direction as described above is applied to the rubber-like elastic inner layer 14 of the face body 13 of the first embodiment, the inside of the high-rigidity outer layer 15 is formed. It is possible to reduce the change in the rigidity of the interface between the elastic inner layer 14 and the highly rigid outer layer 15 while suppressing the change in the Young's modulus in the thickness direction.

Although the embodiments shown in the drawings have been described above, the present invention is not limited to the embodiments described above,
Various modifications can be made to each component within the scope of the invention described in the claims. For example, the high-rigidity outer layer 15 may be made of any material other than the fiber-reinforced resin as long as the material has a Young's modulus larger than that of the rubber-like elastic inner layer. Further, as a modified example of the second embodiment, it is possible to use one in which the Young's modulus of the rubber-like elastic body layer is increased from the central portion in the thickness direction toward both surfaces. Further, the face body 13 may be one in which the outer peripheral edge of the high-rigidity outer layer 15 is protected by surrounding the outer peripheral edge of the high-rigidity outer layer 15 with a metal ring fitted into the recess 11a. Further, it goes without saying that the present invention can be applied to heads such as iron clubs and putters as well as wood clubs.

[0028]

As is apparent from the above description, according to the present invention, the face body behaves elastically within the range of compressive deformation that can be caused by the collision with the ball, and is substantially synchronized with the deformation of the ball. Since the golf club head has rigidity, the flight distance of the ball can be extended by effectively utilizing the collision energy, and a golf club head having excellent durability of the face body can be provided.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of a golf club head showing a first embodiment of the present invention.

FIG. 2 is a partial vertical cross-sectional side view of the head shown in FIG.

FIG. 3 is a partial cross-sectional plan view of the head shown in FIG.

4A is an enlarged cross-sectional view of an essential part schematically showing the layer structure of the face body of the head shown in FIG. 1, and FIG. 4B is a graph showing the Young's modulus of each layer.

FIG. 5 is a partial vertical cross-sectional side view of a golf club head showing a second embodiment of the present invention.

6A is an enlarged cross-sectional view of an essential part schematically showing the layer structure of the face body of the head shown in FIG. 5, and FIG. 6B is a graph showing the Young's modulus of each layer.

FIG. 7 (a) is a cross-sectional view of an essential part showing a modified example of the rubber-like elastic inner layer used in the face body of the first embodiment of the present invention, and FIG. 7 (b) is a graph showing change distribution of Young's modulus thereof.

[Explanation of symbols]

 11 Head Main Body 11a Recess 13 Face Body 14 Rubber Elastic Inner Layer 15 High Rigid Outer Layer 16 High Rigid Outer Layer

Claims (4)

[Claims] 1. A face body having a two-layer structure comprising an inner layer made of a rubber-like elastic body and an outer layer made of a highly rigid body having a Young's modulus larger than that of the rubber-like elastic body is fixed to the face portion of the head body. In a golf club head in which the surface of the outer layer is a head face surface, the Young's modulus of the outer layer changes in the thickness direction so as to decrease toward the inner layer and approach the Young's modulus value of the inner layer. And a golf club head. 2. The golf club head, wherein the Young's modulus of the inner layer changes in the thickness direction so that the Young's modulus of the inner layer increases as the inner layer approaches the outer layer. 3. A face body having a three-layer structure is fixed to a face portion of a head body by sandwiching both surfaces of an inner layer made of a rubber-like elastic body with an outer layer made of a highly rigid body having a Young's modulus larger than that of the inner layer, In a golf club head in which the surface of one of the outer layers is a head face surface, the Young's moduli of the both outer layers are changed in the thickness direction so that the Young's moduli of the outer layers decrease as they approach the inner layer and approach the Young's modulus of the inner layer. A golf club head characterized by. 4. The golf club head according to claim 1, wherein the outer layer is made of fiber reinforced resin in which fiber layers are laminated.