JP3139930B2 - Iron golf club head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an iron golf club head having a face constituting a striking surface and having a hollow portion formed therein.

[0002]

2. Description of the Related Art Various improvements have been made to golf club heads so that the flight distance of a ball after being hit can be increased during golf play. In particular, the iron type golf club head should be configured so that the flight distance of the ball can be extended as much as possible, like the wood type golf club head. However, a sufficient flight distance cannot be expected with conventional golf club heads, and further improvement has been desired.

Conventionally, golf clubs have generally been designed to increase the rigidity of the face portion of a club head, apply a large impact force to the ball when the ball is hit, and increase the coefficient of restitution to extend the flight distance of the ball. The head was designed. The golf club head was constructed based on the idea that the face portion having high rigidity hits the ball and gives a large impact force to the ball, thereby increasing the flight distance of the ball.

However, the present inventors have studied and found that the above-mentioned conventional idea has an error in its basic point. That is, if a large impact force is applied to the ball by increasing the rigidity of the face portion, the energy loss of the ball increases, and the flight distance of the ball cannot be extended much. in this way,
It is considered that one of the reasons why the flight distance of the ball could not be sufficiently increased in the past is that the erroneous idea that the rigidity of the face portion should be increased has become common sense.

[0005] In view of the above, the present applicant can significantly bend and elastically deform the face portion at the time of hitting the ball, thereby suppressing the amount of deformation of the ball, reducing the energy loss and extending the flight distance of the ball. A golf club head was proposed (Japanese Patent Application No. 5-80232). This configuration is not limited to wood-type golf club heads, but can be applied to iron-type golf club heads.However, the present inventor repeated various studies in order to commercialize iron golf club heads of this configuration. The following problems were found.

First, the present inventor manufactured an iron golf club head in which the inside hollow portion was sealed, and changed the thickness and material of the face portion so that the face portion was greatly bent and elastically deformed when hit with a ball. Set to. When the amount of concave deformation of the face portion when the golf club head hit the ball, that is, the amount of flexure thereof, was measured, it was not possible to obtain the amount of flexure as large as expected.

[0007] Then, the present inventor further examined the cause, and was able to clarify the following points. That is, in the iron golf club head described above, even if the thickness and the material of the face portion are set so that the face portion is easily bent and deformed, there is a limit in reducing the rigidity, and the face portion is not affected when the ball is hit. It cannot be sufficiently elastically deformed. Moreover, in the golf club head described above, it is difficult to increase the torsional rigidity of the head portion except for the face portion, so that the head portion except for the face portion is greatly twisted and deformed at the time of hitting the ball, thereby causing energy loss and causing a face loss. It was not possible to increase the amount of deflection of the part as desired.

[0008]

SUMMARY OF THE INVENTION The present invention has been made based on the above-mentioned novel recognition, and an object of the present invention is to provide a simple structure to greatly bend and elastically deform a face portion at the time of hitting a ball. Accordingly, it is an object of the present invention to provide an iron golf club head capable of reliably increasing the flight distance of a ball.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object, and the gist of the invention is
In the club head, the head body and the face
The head is formed separately and the weight distribution of the head is
The center of the back of the head is shifted to the side
To form an opening that is open to
High-strength mare with a thickness of 3 mm or less, having a kgf / mm ² or more
The face part made of zinc steel is welded to the head body.
Characterized by being joined by caulking or crimping
Ian Golf Club Head.

[0010]

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings, and the above-mentioned conventional problems will be more specifically clarified with reference to the drawings.

FIG. 1 is a vertical sectional view showing an iron golf club head 1 according to one embodiment of the present invention, and FIG. 2 is an external perspective view thereof. The club head 1 shown here has a face portion 2 and a main body portion 3 constituting a ball striking surface, and the main body portion 3 includes a top portion 4, a sole portion 5, a toe portion 13, a heel portion 14, and a back portion 6. It is configured. The iron golf club head 1 composed of such components has a hollow portion 7 formed therein. Also, the main body 3 has a shaft 8
Is integrally formed with the neck portion 9 for fixing the head to the head 1. Such a club head 1 is, for example, entirely made of metal.

In this embodiment, as shown in FIG.
Is formed separately from the main body 3, and the face 2 is fitted to the edge of the face side window hole 10 of the main body 3 as shown in FIGS. 1 and 2, and these are welded or welded. And the head 1 are integrally fixed by caulking or the like. As described above, instead of forming the main body 3 and the face 2 as separate members and fixing them to each other, they may be formed in advance as an integral molded product.

The above-mentioned iron golf club is swung in the direction of arrow A as shown in FIG.
The player hits and hits the ball 11 indicated by the dashed line to fly the ball. At this time, as described above,
Conventionally, iron golf clubs generally used are configured to increase the rigidity of the face portion and apply a large impact force to the ball. That is,
When the ball hits the face portion, the thickness of the face portion is set to be large so that the amount of concave deformation of the face portion is as small as possible.

On the other hand, in the iron golf club head 1 shown in FIG. 1, the face portion 2 is configured so as to be greatly recessed and deformed when the ball 11 is hit, as shown by a chain line. That is, the face portion 2 is largely elastically deformed, contrary to the conventionally known iron golf club head. This point is described in Japanese Patent Application No. 5-80.
There is no difference from the specification disclosed in the specification of Japanese Patent No. 232, and according to this configuration, it is possible to greatly increase the flight distance of the ball as described below.

The face portion 2 starts to hit the ball 11, and then the face portion 2 is greatly concavely deformed as shown in FIG. 1, and while the face portion 2 is elastically restored, the striking force is applied to the ball 11 by the strain energy accumulated therein. Is caused to fly, and the amount of deflection when the face portion 2 is maximally recessed is defined as δ. At this time, in the iron golf club head 1 shown in FIG.
And then the ball 11 is again
Is longer than when the amount of deflection is small as in the conventional face portion.

Here, assuming that the ball is hit under the same conditions by the iron golf club head 1 shown in FIG. 1 and the iron golf club head conventionally used generally, the ball hits the face portion, and The impulse to leave is equal to each other. However, as described above, since the club head 1 shown in FIG. 1 is in contact with the ball 11 for a longer time than in the related art, the impact force exerted on the ball 11 by the face portion 2 is smaller than in the related art. The impulse is represented by the product of the contact time between the ball and the face portion and the impact force. Therefore, the longer the contact time, the smaller the impact force.

As described above, when the face portion 2 is largely elastically deformed as shown in FIG. 1, the impact force applied to the ball 11 is reduced, and the amount of deformation of the ball 11 can be kept small. Conventionally, since the amount of concave deformation of the face portion was reduced, the impact force applied to the ball was very large, and the ball was largely elastically deformed. However, in the club head 1 shown in FIG. Since the impact force that the ball 11 receives from the face portion 2 is small, the deformation amount of the ball 11 can be significantly reduced as compared with the related art.

On the other hand, the ball 11 deformed as shown in FIG.
Is returned to the original spherical shape due to its elasticity while contacting the face portion 2 and then is compressed and deformed in a direction orthogonal to the direction shown in FIG. 1, but from the state shown in FIG. When returning to the above, a hysteresis phenomenon is accompanied.

The hysteresis due to the viscoelasticity of the ball 11 increases as the maximum deformation increases.
Therefore, if the ball receives a large impact force from the face portion and undergoes a large compressive deformation as in the prior art, the hysteresis loss when the ball returns to the original form becomes extremely large, resulting in a large energy loss. As a result, the coefficient of restitution of the ball is reduced, and the speed of the ball that has left the face portion is reduced, so that the ball cannot fly far.

On the other hand, in the iron golf club head 1 shown in FIG. 1, the face portion 2 is largely elastically deformed, whereby the amount of deformation of the ball 11 can be kept small. The hysteresis loss when returning to the spherical shape is extremely small, and the energy loss is reduced. By suppressing the deformation of the ball 11, the hysteresis loss can be effectively reduced. For this reason, the coefficient of restitution of the ball 11 is much higher than in the past, so that the speed of the ball 11 that has left the face portion 2 can be increased, and its flight distance can be greatly increased.

The ball 11 flying away from the face portion 2 vibrates while being alternately deformed in the direction shown in FIG. 1 and the direction orthogonal thereto. If the amount of deformation of the ball 11 is small as shown in FIG. 1, the amplitude of the vibration during flight also becomes small, so that the energy loss of the ball 11 due to this vibration also decreases, thereby also increasing the flight distance of the ball 11. It becomes possible. If the ball is greatly deformed when hitting the face portion as in the prior art, the ball vibrates violently during the flight, thereby increasing the energy loss of the ball and reducing its flight distance. .

As described above, in order to extend the flight distance of the ball, the structure itself in which the face portion 2 is largely elastically deformed at the time of hitting the ball is disclosed in Japanese Patent Application No. 5-8023.
There is no difference from that disclosed in No. 2. However, as described above, if only the conventionally proposed configuration is used,
Even if the thickness of the face portion is reduced so that the face portion can be sufficiently bent and deformed at the time of hitting the ball, it is difficult to elastically deform the face portion at the time of the actual hitting of the ball. That is, as shown in FIG. 5, in the case of the iron golf club head 1a in which the hollow portion 7a defined by the face portion 2a and the main body portion 3a is completely sealed, the face portion 2a is easily bent and deformed. Even if the thickness is set small, it is difficult to lower the rigidity of the face portion 2a, and the face portion 2a is not sufficiently bent and deformed at the time of hitting a ball. The cause is that the back surface 6a shown in FIG. 5 increases the rigidity of the face 2a.

Therefore, in the iron golf club head 1 of the present embodiment, as shown in FIG. 4, an opening for opening the hollow portion 7 inside to the outside is formed at the center of the back portion 6 of the head 1. 12 are formed. As described above, the shell structure in which the back surface portion facing the face portion 2 is open can reduce the rigidity of the face portion 2, and by setting the thickness and the material as described later,
When the ball is hit, the face portion 2 can be largely bent and elastically deformed as shown by a chain line in FIG.
Can effectively extend the flight distance. This has been confirmed by numerous experiments.

Further, by forming the opening 12 in the back surface 6, the weight of the opening 12 can be shifted to the peripheral portion of the main body 3, whereby the face portion can be shifted without changing the weight of the head 1. 2, the torsional rigidity of the head portion, that is, the main body portion 3 can be increased. That is, assuming that the total weight of the head 1 shown in FIG. 1 is equal to the total weight of the head 1a shown in FIG. 5, by forming the opening 12 as in the head 1 shown in FIG. When the opening is not formed, the weight thereof can be transferred to the peripheral portion of the main body 3, thereby increasing the torsional rigidity of the head 1. As described above, when the main body 3 excluding the face portion 2 is greatly twisted and deformed at the time of hitting the ball, a large energy loss occurs, and thus the amount of deflection of the face portion 2 cannot be increased. However, in the configuration shown in FIGS. 1 to 4, by forming the opening 12, the torsional rigidity of the main body 3 can be increased, and when the ball 11 is hit,
The torsional deformation of the main body 3 can be effectively suppressed. As a result, when the ball is hit, the face portion 2 can be largely recessed and deformed as described above, and the flight distance of the ball 11 can be extended without any trouble. The opening 12 is the face 2
The opening 12 allows the ideal iron golf club head 1 to be formed while reducing the rigidity of the golf club head and increasing the torsional rigidity of the main body 3.

If the opening 12 is formed in the center of the back portion 6, the center of gravity of the golf club head 1 can be lowered, whereby the ball 11 after hitting can be raised greatly, and The flying distance increasing effect can be further enhanced. In addition, the formation of the opening 12 shifts the weight distribution of the golf club head 1 toward the periphery thereof, so that the moment of inertia of the head 1 can be increased and the directionality of the ball can be improved.

By the way, in the iron golf club head 1 described above, in order to increase the amount of deflection δ of the face portion 2 at the time of hitting a ball, the thickness t (FIG. 1) is made as small as possible so that it can be greatly bent and deformed. Need to be However, if this thickness is made too small,
When the ball is hit, the face portion 2 may be plastically deformed. From such a viewpoint, the face portion 2 of the golf club head 1 shown in FIGS. 1 to 4 is set to have a thickness of 3 mm or less, and the face portion 2 has a thickness of 120 kgf / mm.
It is composed of a high-strength material that exhibits ^two or more bending strengths. If the face portion 2 is made of a material having high strength in this way, even if the thickness t is set to 3 mm or less,
This can prevent plastic deformation. In addition, by setting the thickness t to be thin as described above, the face portion 2 can be largely elastically bent and deformed at the time of hitting a ball, and a large amount of deflection δ can be obtained.

As the above-mentioned high-strength material, it is advantageous to use, for example, high-tensile steel, particularly maraging steel. The use of maraging steel can prevent plastic deformation of the maraging steel even if the thickness is extremely thin, 3 mm or less.

The bending strength of high-strength materials currently used for general structural members is generally 260 to 270 kg.
f / mm ² , and therefore the face 2
However, it is preferable that the material be formed of a material having a bending strength of this value at the maximum, but if a material having a higher bending strength is developed in the future, it can be used, of course.

The lower limit of the thickness t of the face portion 2 can be set to an appropriate value of 3 mm or less depending on the material used for the material. However, even when the impact force applied to the face portion 2 is particularly large, the lower limit is set. In order to prevent plastic deformation, the thickness t may be set to a minimum of 0.5 mm. However, the thickness t can also be made smaller than the above-described value depending on the material used, the usage conditions of the golf club, and the like.

When the face portion 2 and the main body portion 3 are integrally formed in advance, the main body portion 3 is also made of the above-described high-strength material. However, as in this embodiment, the face portion 2 and the main body portion 3 are formed by separate members. When configuring, the main body 3 can be configured by selecting an appropriate material including the high-strength material described above. For example, in addition to metals such as stainless steel and aluminum alloy, the main body 3 can be made of synthetic resin.

According to the iron golf club head of the present invention , the face portion can be largely bent and elastically deformed at the time of hitting the ball, so that the deformation of the ball is suppressed, the energy loss is reduced, and the flight distance of the ball is increased. Can be stretched. Plastic deformation of the face portion can also be prevented.
Also , since an opening is formed in the back surface, the rigidity of the face portion can be reduced, the torsional rigidity of the head portion other than the face portion can be increased, and the amount of deflection of the face portion at the time of impact can be increased. The effect described above can be obtained more reliably. Furthermore, by the opening formed in the back part,
It is possible to lower the center of gravity of the iron golf club head, so that the ball can be raised higher. Moreover, by increasing the moment of inertia of the head,
It is also possible to improve the directionality of the ball.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of the iron golf club head of one embodiment of the present invention, taken along line II in FIG.

FIG. 2 is a perspective view of the iron golf club head shown in FIG. 1;

FIG. 3 is a perspective view showing a state before a face portion is fixed to a main body portion.

FIG. 4 is a view of the iron golf club head shown in FIG. 1 as viewed from a back side.

FIG. 5 is a cross-sectional view similar to FIG. 1, showing an iron golf club head having no opening in the back part.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Iron golf club head 2 Face part 6 Back part 7 Hollow part 12 Opening t Thickness

──────────────────────────────────────────────────の Continued on the front page (72) Inventor Takeo Futada 288 Matsuhidai, Matsudo-shi, Chiba Prefecture Maruman Golf Co., Ltd. Matsudo Plant (72) Inventor Hideaki Kuroda 288 Matsuhidai, Matsudo-shi, Chiba Maruman Golf Co., Ltd. Matsudo Plant (56) References JP-A-6-343723 (JP, A) JP-A-6-86842 (JP, A) JP-A-63-270069 (JP, A) JP-A-56-6471 (JP, U) Kaihei 1-176467 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) A63B 53/00

Claims (1)

(57) [Claims] 1. An iron golf club head,
The head body and the face part are formed separately, and the head
The weight distribution is shifted to the periphery of the head.
An opening to the outside is formed in the center of the back of the head
And, further, the wall thickness having a flexural strength 120 kgf / mm ² or more
Face part made of high strength maraging steel of 3mm or less
To the head body by welding or caulking.
An iron golf club head characterized by being formed.