JPH06114127A - Golf club head - Google Patents

Abstract

PURPOSE:To provide a golf club head capable of increasing the flying distance of a ball by increasing the coeffts. of repulsion of the ball and the club head. CONSTITUTION:A face body 14 to be mounted in a recess 11a formed on the face surface of a head body 11 is constituted of a rigid plate 15 housed in the recess and plural pieces of elastic bodies 16 disposed between the rigid plate and the inside base of the recess. The respective elastic bodies have a biconvex faced lens shape. The face body has the nonlinear elastic characteristics nearly satisfying the relation kb/kc=Mb/Mc with the same arbitrary load when the spring constants at the time of arbitrary loading of the golf ball and the face body are respectively designated as kb, kc and the mass respectively as Mb, Mc.

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 capable of extending a flight distance of a golf ball.

[0002]

2. Description of the Related Art In order to increase the initial velocity of a ball when hitting a ball and increase the flight distance of the ball, it is important to maximize the coefficient of restitution between the ball and the club head. It is desirable that the ball is deformed in synchronization with the deformation of the ball.

In order to realize such tuning transformation,
It is necessary that the face part of the head has a rigidity (spring constant) that is substantially in tune with the deformation of the ball within the range of the compressive deformation due to the collision with the ball, and has an elastic behavior within the range of the compressive deformation due to the collision with the ball Is. In order to synchronize the deformation of the head face part and the ball,
The spring constants of the ball and the head face are k
When b, kc and mass are Mb, Mc respectively, the spring constant of the head face part is

## EQU2 ## It is necessary to satisfy the relationship of kb / kc = Mb / Mc.

Therefore, the present applicant has filed Japanese Patent Application No. 4-13629.
No. 2 proposes a golf club head in which a face body having a rubber-like elastic plate and a fiber reinforced resin (FRP) surface layer covering the surface of the elastic plate is provided on the face portion of the head body. Since the face body of such a golf club head can perform elastic behavior within the range of compressive deformation that can occur due to collision with the ball, and has rigidity that is substantially in synchronization with the deformation of the ball, it increases the flight distance of the ball. It becomes possible.

However, while the elastic deformation of the ball at the time of hitting has a non-linear characteristic, the conventionally proposed composite face body of a rubber-like elastic body and an FRP surface layer has a substantially linear elastic characteristic. Therefore, the synchronous deformation of the face body and the ball is only approximate.

Therefore, when a composite face body having such linear elastic characteristics is used, its rigidity (spring constant) is desirably determined by the following method.

That is, the ball generally has a non-linear elastic characteristic as shown in FIG. In the figure, the vertical axis represents the load Pb applied to the ball, and the horizontal axis represents the deformation amount (compression amount) δb of the ball due to the load. When the club head hits the ball at a speed of v = 40 m / sec, if the ball contracts a maximum of about 5.67 mm, the amount of deformation δb = 5.67 m
The secant rigidity Kb of the ball at m is determined, and the rigidity kc of the face body (see FIG. 11B) is determined so as to satisfy the following equation 3 with respect to the secant rigidity Kb.

[Formula 3] Kb / kc = Mb / Mc

[0008]

The stiffness determining method described above is the best method when a face body having a linear elastic characteristic is used, but the face body has a linear elastic characteristic with respect to the non-linear elastic characteristic of the ball. Energy loss is inevitable because of the essential difference. Therefore, there is a limit in increasing the coefficient of restitution between the ball and the club head.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a golf club head which can solve the above-mentioned drawbacks and further increase the coefficient of restitution between the ball and the club head to increase the flight distance of the ball.

[0010]

In order to solve the above-mentioned problems, the present invention provides a golf club head having a face body mounted on the face surface of a head body, wherein the spring constant of the golf ball and the face body under an arbitrary load. Respectively k
When b, kc and mass are Mb, Mc respectively, the face body is

## EQU00004 ## A golf club head having a non-linear elastic characteristic that substantially satisfies the relationship of kb / kc = Mb / Mc.

In one aspect of the present invention, a face body is housed in a recess of the head main body, and a plurality of elastic members arranged between the rigid plate and the bottom surface of the head main body in the recess. And a body, and each elastic body has a biconvex lens shape.

According to another aspect of the present invention, two elastic plates housed in the recess of the head body, a rigid plate disposed on the surface of the elastic plate on the opening side of the recess, and both elastic plates. And a plurality of rigid bodies disposed between them, each rigid body having a biconvex lens shape.

In still another aspect of the present invention, the face body includes two elastic plates housed in the recess of the head body, and a rigid plate disposed on the surface of the elastic plate on the opening side of the recess. , And a plurality of rigid bodies arranged between both elastic plates, and each rigid body has a biconvex lens shape.

In still another aspect of the present invention, the face body has two rigid plates housed in the recess of the head main body, and a plurality of elastic bodies arranged between the rigid plates.
Each elastic body is partially composed of a coil spring having a different coil pitch or winding diameter.

[0015]

In the golf club head having the above-described structure, the face body has a non-linear elastic characteristic that substantially satisfies the condition of the equation 4 for an arbitrary same load, so that the face body is substantially ideal during the deformation process of the ball at the time of hitting the ball. Tuned and transformed
Since the energy loss becomes very small, the coefficient of restitution between the ball and the club head increases, and the flight distance of the ball increases.

[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.

1 and 2 show an embodiment of the present invention. FIG. 1 is a partially sectional side view of a golf club head, and FIG. 2 is a partially cutaway front view of a head. Referring to these figures, the club head 10 has a hollow main body 11 made of metal such as stainless steel or light alloy, or fiber-reinforced resin, fiber-reinforced metal, or the like, and a head body 11.
And a neck portion 12 formed integrally with the heel end of the golf club, and a shaft mounting hole 12a for inserting the club shaft 13 is formed in the neck portion 12.

A recess 11 is formed in the face portion of the head body 11.
a is formed, and a face body 14 having a non-linear elastic characteristic described later is inserted in this recess. Here, the face body 14 is made of, for example, a rigid body plate 15 made of carbon fiber reinforced resin, and a plurality of face bodies 14 (here 6
Individual rubber-like elastic bodies 16 and each elastic body 16 has a biconvex lens shape. The rigid plate 15 is fixed to the elastic body 16, but is slidably fitted in the recess 11 a of the head body 11.

The face body 14 is a golf ball 17
When the spring constants of the face body 14 under an arbitrary load are kb and kc and the masses are Mb and Mc, respectively, as shown in FIG.

## EQU5 ## It has a non-linear elastic characteristic that substantially satisfies the relationship of kb / kc = Mb / Mc.

Next, a method of manufacturing the elastic body 16 used for the face body 14 having such characteristics will be described with reference to FIGS.

FIG. 3 shows the relationship between the golf ball 17 and the half body 16a of the elastic body 16 when hitting a ball. In this embodiment, the half-split body 16a has a curved surface with a radius r and has a thickness t. Head 10 is ball 1 with load Pc
When the deformation amount of the half body 16a of the elastic body 16 when it collides with 7 is δc, the contact area A with the inner bottom surface of the recess 11a of the head body 11 or the back surface of the rigid body 15 when the deformation amount δc is

[Equation 6] Can be expressed as Therefore, when the Young's modulus of the half-split body 16a is E, the relationship between the load Pc and the deformation amount δc is

[Equation 7]

[Equation 8] Can be expressed as

On the other hand, the load Pb applied to the golf ball 17
According to the experiment, the relationship between the

[Equation 9] Since the Pb = 460δb ^2, and differentiating this,

[Equation 10] Becomes

The condition under which the deformations of the face body 14 and the golf ball 17 are perfectly synchronized is that the relation of the above equation 5 is satisfied with respect to an arbitrary same load. Therefore, in the above equation 5, Mb = 46 g and Mc = 200 g. Then, kc = 4.3 kb.
Therefore, if the load applied to the face body 14 is Pc and the deformation amount of the face body 14 is δc,

[Equation 11] It becomes a relationship.

Since the elastic body 16 has a shape in which two half-divided bodies 16a each having a thickness t are combined, if n elastic bodies 16 are arranged, one elastic body 16 is obtained from the equation (7). Is

[Equation 12] Therefore, in the total n elastic bodies 16 in the face body 14,

[Equation 13]

[Equation 14] Becomes Therefore, by substituting Equation 10 and Equation 13 into Equation 11,

[Equation 15] Becomes Here, since Pb = Pc, Equation 9 and Equation 1
From 4,

[Equation 16] Therefore,

[Equation 17] Becomes Further substituting equation 17 into equation 16,

[Equation 18] Therefore,

[Formula 19] Here, if you square both sides of Equation 19,

[Equation 20] Becomes Here, r = 20 mm, E = 140 N / mm ² , t =
If it is 3 mm, n = 5.8 from the equation 20, so that the required number of elastic bodies 16 is 6. Also, FIG.
On the other hand, as shown in (a), a half-divided body 16 having a thickness t = 3 mm
The diameter d1 of a is 21 mm, but in order to allow the head body 11 to be housed in the recess 11a, the outer edge that has little influence on deformation is removed, and as shown in FIG. d2
It is preferable to use the elastic body 16 of 15 mm.

The elastic body 16 may be formed by adhering two half-split bodies 16a together, but may be integrally formed.

In the golf club head having the above structure, the face body 14 has a non-linear elastic characteristic that substantially satisfies the tuning condition of the above equation 5 for an arbitrary same load. Since the body 14 undergoes an almost ideal entrainment deformation and the energy loss is very small, the ball 17 and the club head 10
The coefficient of repulsion with respect to increases, and the flight distance of the ball 17 increases. Also, the deformation amount δ of the ball 17 at the time of impact
When b is, for example, about 5.67 mm, the deformation amount δc of the elastic body 16 in the face body 14 is about 1.32 mm. At this time, the strain εε of the elastic body 16 is 1.32 / 6.00 = 0.22, which is within the elastic range of the elastic material such as rubber. Therefore, the elastic body 16 behaves elastically within the range of compressive deformation due to impact, and can be deformed to satisfy the tuning condition of the above equation 5.

FIG. 6 shows another embodiment of the present invention. In this embodiment, the face body 14 is the head body 1.
Two rubber-like elastic plates 1 housed in the recess 11a
8 and 19 and a plurality of rigid bodies 20 arranged between the elastic plates 18 and 19 along the face surface, and each rigid body 20 has a biconvex lens shape having a convex curved surface having substantially the same curvature as the golf ball. I am doing it. The rigid body 20 can be made of a metal such as iron, aluminum, or titanium, or glass, plastic, or the like. Further, a rigid plate 21 made of, for example, carbon fiber reinforced resin or metal is fixed to the surface of the elastic plate 18 on the opening side of the recess 11a. The rigid plate 21 serves to disperse the load applied to the elastic plate 18 at the time of impact and protects the surface of the elastic plate 18, so that it helps prevent scratches on the surface of the face body 14 and improve durability.

Also in this embodiment, the elastic plates 18, 19 are
By Young's modulus E = 140 N / mm ² , thickness t = 3 mm, the rigid body 20 has the same size and shape as the elastic body 16, and the same number of rigid bodies 20 are used. The face member 14 that satisfies the condition 5 can be obtained, and the same effect as that of the above-described embodiment can be obtained.

FIG. 7 shows a face body according to another embodiment of the present invention. The face body 14 has a plurality of rubber-like elastic bodies 24 arranged between two rigid bodies 22 and 23, and each elastic body 24 has a plano-convex lens shape having a convex curved surface. In the case of this embodiment, the same effect can be obtained by forming the elastic body 24 with an elastic material that is harder than the elastic body 16 of the embodiment shown in FIGS.

FIG. 8 shows a face body in still another embodiment of the present invention. This face body 14 is 2
A plurality of coil springs 27 as elastic bodies are arranged between two rigid bodies 25 and 26.
No. 7 has a non-linear elastic characteristic by, for example, making the coil pitch interval between both end portions 27a and 27b smaller than the coil pitch interval between the central portions 27c. Therefore, as schematically shown in FIG. 9, when the deformation amount δc of the coil spring 27 is small, the entire coil spring 27 acts as a spring, but the deformation amount δc becomes large and the end portions 27a and 27b of the coil spring 27 are If the coils contact each other, that part will not function as a spring,
The spring constant (rigidity) of the coil spring 27 changes. Therefore, by using such a coil spring 27, it is possible to obtain the same effect as that of the embodiment shown in FIGS. 1 and 2.

Although the embodiment shown in the drawings has been described above, the present invention is not limited to the above-described embodiment. For example, as a modification of the embodiment shown in FIG. Alternatively, as a modification of the embodiment shown in FIG. 6, a rigid body may be integrally molded with the elastic plate to be embedded in the elastic plate. Further, one of the two rigid plates in the embodiments shown in FIGS. 7 and 8 may be formed by the bottom wall portion of the recess formed in the face surface of the head body. Furthermore, FIG.
10 (a) or (b) in place of the coil spring 27 shown in FIG.
Even if a coiled coil spring 28 or a barrel coiled spring 29 having a partially different winding diameter is used, the same effect can be obtained.

[0032]

As is apparent from the above description, according to the present invention, the face body has a non-linear elastic characteristic that substantially satisfies the condition of synchronous deformation with the ball under an arbitrary same load. During the deformation process, the face body undergoes an almost ideal tuned deformation, and the energy loss becomes very small, so that the coefficient of restitution between the ball and the club head increases. Therefore, it is possible to provide a golf club head capable of increasing the flight distance of the ball.

[Brief description of drawings]

FIG. 1 is a partial vertical cross-sectional side view of a golf club head showing an embodiment of the present invention.

FIG. 2 is a partially cutaway front view of the club head shown in FIG.

FIG. 3 is a diagram for explaining a tuning condition of an elastic body and a ball in the embodiment shown in FIGS. 1 and 2.

FIG. 4 is a diagram showing a dimension setting example of the elastic body of the embodiment shown in FIGS. 1 and 2;

FIG. 5 is a graph showing the relationship between the spring constant (rigidity) of the face body and the spring constant (rigidity) of the ball of the golf club head according to the present invention.

FIG. 6 is a partial vertical cross-sectional side view of a golf club head showing another embodiment of the present invention.

FIG. 7 is a side view showing the structure of a face body according to another embodiment of the present invention.

FIG. 8 is a side view showing the structure of a face body according to still another embodiment of the present invention.

9 is a graph illustrating the relationship between the deformation amount and the deformation state of the face body shown in FIG.

FIG. 10A is a cross-sectional view showing an example of an hourglass coil spring as a modified example that can be replaced with the coil spring of the embodiment of FIG.
(b) is sectional drawing which shows the example of a barrel-shaped coil spring.

FIG. 11A is a graph for explaining the relationship between the deformation at impact of a golf ball and the secant rigidity, and FIG. 11B is a graph showing the deformation and rigidity at impact of a conventional face body having a linear elastic characteristic. It is a figure which shows a relationship.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 golf club head 11 head body 11a recess 14 face body 15 rigid plate 16 biconvex lens-shaped elastic body 16a half-divided body 17 golf ball 18, 19 elastic plate 20 biconvex lens-shaped rigid body 21 rigid plate 22, 23 rigid plate 24 plano-convex lens Elastic body 25,26 rigid plate 27 coil spring

Claims (5)

[Claims] 1. A golf club head having a face body mounted in a recess formed in the face surface of a head body,
Assuming that the spring constants of the golf ball and the face body under an arbitrary load are kb and kc, and the masses are Mb and Mc, respectively, the face body is given by the following equation: kb / kc = Mb / A golf club head having a non-linear elastic characteristic that substantially satisfies the relationship of Mc. 2. A face body has a rigid plate housed in the recess of the head body, and a plurality of elastic bodies arranged between the hard plate and the bottom surface of the face body of the head body in the recess.
The golf club head according to claim 1, wherein each elastic body has a biconvex lens shape. 3. A face body is provided between two elastic plates housed in a recess of the head body, a rigid plate disposed on the surface of the elastic plate on the opening side of the recess, and between the elastic plates. 2. The golf club head according to claim 1, further comprising a plurality of rigid bodies, each rigid body having a biconvex lens shape. 4. The face body has two rigid plates housed in the recess of the head body and a plurality of elastic bodies arranged between the rigid plates, each elastic body having a plano-convex lens shape. The golf club head according to claim 1, wherein: 5. The face body has two rigid plates housed in the recess of the head body, and a plurality of elastic bodies disposed between the rigid plates, each elastic body partially having a coil pitch. The golf club head according to claim 1, wherein the golf club head is made of a coil spring having a different winding diameter.