JPH0663184A - Golf club head and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a golf club head for every of golfers including a beginner, a weak woman and an old man in accordance with his or her skill and force strength. CONSTITUTION:Slurry in which a material powder composed of two kinds of large and small particle size powders mixed together is dispersed in a water solution in which a binder is dissolved, is filled in a porous mold 1 so that the water content is absorbed into the porous mold while the mold is suitably rotated or swung so as to form a metal powder hollow compact 10 having a high density layer 13, on the surface side of a cavity 2, in which the small particle size powder 12 is mainly concentrated, and a low density layer 15 near to the center part of the molding in which the large particle size metal powder 14 is mainly concentrated, and having a density gradient such that the density of the large size particle powder is gradually increased from the high density layer 13 to the low density layer 15. Then, this compact 10 is sintered so as to produce a metal powder sintered compact having a density gradient such that the density is gradually decreased from the outer surface to the center of the compact. With this arrangement, a golf club head having a smooth and high strength surface, having a low specific weight and a low elastic modulus as a whole, and having a small weight and a stable ballistic path can be optionally manufactured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a golf club, and more particularly to a head structure and a manufacturing method thereof.

[0002]

2. Description of the Related Art The head of a conventional golf club is made by forging or precision casting (lost wax) of ferrous metal such as stainless steel.

The iron-based metal golf club head has a high elastic modulus of iron of about 20,000 kgf per square mm, and therefore the amount of elastic deformation of the face surface when hitting a ball is small.

Therefore, when the ball is hit, the time during which the ball is in contact with the face surface is short and the flight distance is long, but it is difficult to control the direction of the ball.

For this reason, various design considerations have been made by changing the shape of the groove provided on the face surface for hitting the ball and the position of the center of gravity, and the sweet spot is widened to provide a stable trajectory with a large spin and a large flight distance. Various attempts have been made to develop a head devised so as to obtain it.

[0006] Recently, various improvements in terms of materials have been studied, for example, the elastic modulus is 12000 per square mm.
Some heads made of non-ferrous metal, whose elastic modulus is much lower than that of iron such as beryllium copper alloy of about kgf, have been commercialized.

[0007]

However, in the case of iron, no matter how the design is improved, the elastic modulus of iron is basically high as described above, so that a beginner can enjoy a stable trajectory and a great flight distance. It's difficult to say.

In the case of the above-mentioned copper alloy, since the elastic coefficient is low, the trajectory is stable, but the flight distance cannot be obtained, and the mechanical strength is low, so that the ball striking surface is easily dented or scratched. Not practical.

More recently, golfers with weak powers such as women and old people are increasing, but in order to fully enjoy the flight distance with such golfers, the shaft should be lengthened to increase the head speed. Good.

In this case, if the shaft length is long, it is difficult for a beginner to hit the ball accurately by hitting the ball, so it is necessary to increase the head, but in the case of iron-based alloys, the specific gravity is 7.2 to 8. Since it is as high as 9, it becomes heavy and cannot be increased.

The present invention solves the above-mentioned drawbacks of the prior art and enables golf clubs such as beginners, women, and the elderly who have weak power to enjoy a sufficiently stable trajectory and flight distance, and also an inexpensive golf club head and its head. It is intended to provide a manufacturing method.

[0012]

That is, according to the present invention, a metal powder having a small particle size on the surface side is formed by molding a raw material powder, which is a mixture of metal powders having a large size and a small size, into a predetermined golf club head shape and then sintering the powder. A golf club characterized by being formed as a metal powder sintered body having a density gradient that forms a high-density layer in which a large amount of powder is distributed and becomes a low-density layer in which a large amount of metal powder having a large particle size is distributed toward the center. A slurry in which a raw material powder, which is a head and which is mixed with metal powders of two different sizes, is dispersed in water in which a binder is dissolved is poured into a porous mold through an injection port, and the injection port is sealed with this mold. It was mounted on a post-rotation oscillating device to allow the porous mold to absorb the water content in the slurry while rotating and / or oscillating, and the surface side of the powder was distributed with a large amount of metal powder with a small particle size and became denser toward the center Then, a metal powder compact having a density gradient such that a large amount of metal powder having a large particle size is distributed and having a low density is formed, and the metal powder compact is taken out from the porous mold and sintered to obtain the density gradient. A method for manufacturing a golf club head, which is characterized in that the metal powder sintered body is used.

[0013]

The present invention is constructed as described above, and since the surface is a high-density layer made of metal powder having a small particle size, it is smooth and has high mechanical strength, and there is no problem as a ball striking surface. Since the density gradient is such that it becomes a high-density layer made of metal powder having a large particle size, the overall elastic modulus and specific gravity decrease.

Furthermore, since the degree of density gradient can be controlled by changing the particle size and the amount of the metal powder having a large particle size to be mixed as the raw material powder, the overall density and specific gravity can be changed quite freely.

As a result, even when an iron-based alloy such as stainless steel is used, the overall elastic modulus is low and a stable trajectory can be obtained even for beginners. Further, a large head with a wide sweet spot can be used for a long shaft. You can create a club that meets the demands of golfers, such that even a golfer with a weak force can get a great flight distance.

Moreover, since a particularly expensive device is not used for manufacturing such a head and a lot of man-hours are not required, the manufacturing cost is low.

[0017]

Embodiments of the present invention will now be described with reference to the drawings.

First, a porous mold 1 having a cavity 2 and an injection port 3 communicating with the cavity 2 as shown in FIG. 1 is prepared.

The porous mold 1 is formed as a porous ceramic mold or a gypsum mold containing silicon dioxide-alumina as a main component, and these molds divide a master model of the product shape into two parts with a parting line as a boundary. A ceramic or gypsum slurry is cast and then fired to form a split die.

The slurry 4 is injected into the cavity 2 through the injection port 3 of the porous mold 1 in which the respective molds divided as described above are combined, and casting is performed.

The slurry 4 is obtained by adding about 15 to 17% by volume of water to the raw material powder and about 0.2 to 1.0% of ammonium alginate as a binder and mixing them.

The raw material powder is stainless steel alloy SUS31.
6 L of an extremely small powder having an average particle size of 9 μm and an extremely large powder having an average particle size of about 50 to 100 μm are mixed in a volume of about 1: 1 to 1: 2.

In the mixing of the raw material powders, when the average particle size of the metal powder having a large particle size is increased and the mixing amount is increased, the elastic modulus and the specific gravity of the finally formed and formed sintered body are lowered, so that it is required. These are appropriately changed in consideration of the elastic modulus and the specific gravity.

If the slurry 4 is completely injected into the cavity 2 of the porous mold 1, as shown in FIG. 2, the injection port 3 is made of the same porous material as that of the mold 1 to form the plug 5. Is fitted and sealed, and is housed and fixed in the holder 7 of the rotary rocking device 6 as shown in FIG.

Thereafter, in order to separate the large and small metal powders in the slurry 4 from each other into a state in which the particle size is inclined, the holder 7 is rotated by the motor 8 about the horizontal axis, or as shown in FIG. , Is oscillated up and down by the motor 9 about the axis in the vertical direction, or oscillated while being rotated again.

The movement for rotating and / or swinging the holder 7 needs to be performed according to a program according to the casting condition which has been determined in advance by experiments.

The reason for the ease of particle size inclination when the large and small metal powders in the slurry 4 are separated is that the slurry 4 is different in particle size and compounding ratio of the large and small metal powders, the kind and amount of the binder, and the water content. This is because it varies depending on the mixing conditions of itself and the casting conditions such as the water absorption of the porous mold 1.

The drive of the motors 8 and 9 is controlled by a program determined according to the casting conditions, and the rotation speed of the holder 7 is changed, the swing speed and angle are changed, or the movement is stopped appropriately. However, when the holder 7 is rotated and / or oscillated, a large amount of the metal powder having a small particle size in the slurry 4 easily gathers on the surface side of the cavity 2 toward the center, so that the metal powder having a large particle size is generated. It will be a lot of people.

When the above-mentioned rotation and / or rocking motion is continued, the water content in the slurry 4 is absorbed by the porous mold 1, and as shown in FIG. 5, the water content is absorbed and the volume is reduced. A powder compact 10 having a cavity 11 at the center is formed.

Further, as shown in the partially enlarged view of FIG. 5, this powder compact 10 has a large amount of small-diameter metal powder 12 gathered on the surface side of the cavity 2 to form a high-density layer 13, and as it goes toward the center side. The low-density layer 15 in which a large amount of the large-diameter metal powder 14 is collected has a density gradient.

Powder compact 1 formed as described above
When 0 is sintered after the porous mold 1 is divided and taken out,
A head of a golf club is manufactured as a metal powder sintered body having a density that is high on the surface and decreases toward the center.

Sintering of the molded body 10 is carried out according to a conventional method. When the metal powder is stainless steel, the temperature is raised to 500 ° C. at a heating rate of about 30 ° C./hour in a nitrogen atmosphere, and the temperature is maintained for about 3 hours to remove the metal. Binder treatment, then 0.001 to
It is performed by heating at 1250 ° C. for about 2 hours in a vacuum of about rr.

[0033]

EFFECTS OF THE INVENTION The present invention has the above-described structure and operation. Since the surface is a high-density layer in which a large amount of small iron-based metal powders are distributed, a strong, smooth, and good hitting surface can be obtained. Has been formed.

Further, a low-density layer having a lower density is formed from the surface side formed by the high-density layer toward the center, and the central portion is hollow, so that the specific gravity is about 5 as a whole. , Elastic modulus is 1 per 1 mm2
Approximately 300 kgf, which is considerably lower than that of iron even though it is a powder sintered body of iron-based metal.

Further, the specific gravity and elastic modulus are changed by changing the particle size and the compounding amount of the metal powder having a larger average particle size in the raw material powder to change the density of the low density layer or changing the water content in the slurry. It can be adjusted freely by changing the size of the central cavity.

As a result, it is possible to provide a head with a large and wide sweet spot and a stable trajectory for golfers with weak power such as beginners, women and old people, and for all golfers. Therefore, it is possible to freely provide the optimum head according to the degree of skill and strength of the skill.

[Brief description of drawings]

FIG. 1 shows the state of injection of slurry into a porous mold,

FIG. 2 shows a state where the slurry has been injected into the porous mold,

FIG. 3 shows a rotation state of the rotary oscillating device,

FIG. 4 is a swing state of the rotary swing device,

FIG. 5 shows a state of forming a metal powder compact.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Porous type 2 Cavity 4 Slurry 6 Rotating rocking device 10 Metal powder compact 11 Cavity 12 Small diameter metal powder 13 High density layer 14 Large diameter metal powder 15 Low density layer

Claims (2)

[Claims] 1. A high-density layer on the surface side of which a large amount of small-sized metal powder is distributed is formed by molding a raw material powder, which is a mixture of large- and small-sized metal powders, into a predetermined golf club head shape and then sintered. A golf club head, characterized in that the golf club head is formed as a metal powder sintered body having a density gradient that forms a low density layer in which a large amount of metal powder having a large particle size is distributed toward the center. 2. A slurry in which a raw material powder obtained by mixing metal powders of two different sizes, large and small, is dispersed in water in which a binder is dissolved is poured into a porous mold through an injection port, and the mold is sealed after the injection port is sealed. Although it was attached to a rotary rocking device and was allowed to rotate and / or rock while moving, water in the slurry was absorbed into the porous mold, and a large amount of metal powder with a small particle size was distributed on the surface side and the density became high toward the center. Then, a metal powder compact having a density gradient such that a large amount of metal powder having a large particle size is distributed and having a low density is formed, and the metal powder compact is taken out from the porous mold and sintered to obtain the density gradient. A method for producing a golf club head, which is characterized in that a metal powder sintered body is provided.