JPH11137741A - Manufacture of club head for golf - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a molding process, to reduce the manufacturing cost, and to stabilize the quality. SOLUTION: In the molding of a head made of a desired metal base material by a metal powder injection molding means, a head forming material 21 composed of a powder material of a metal base material for forming a head, is filled in a cavity 11 of a metal mold 10 having the shape of a desired head, simultaneously a material 22 for molding a weight body composed of a powder material of a different metal having a coefficient of thermal expansion same as that of the metal base material of the head where the weight body is to be formed, and having the specific gravity higher than that of the metal base material of the head, is filled by a two-color molding or the like, and a head green body 20 is injection molded. This head green body 20 is heated and sintered.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a golf club head by injection molding of a metal powder, and more particularly, to a method of forming a head made of a desired metal base material by devising the joining of a weight body. This simplifies the process to reduce the manufacturing cost and stabilize the quality.

[0002]

2. Description of the Related Art Conventionally, in manufacturing a golf club head of this kind, for example, an iron club head, a head made of a desired metal base material such as titanium (Ti) or a titanium alloy is formed by casting or forging. In addition, in order to improve the hitting characteristics such as lowering the center of gravity, expanding the sweet area by adjusting the depth of the center of gravity, and increasing the moment of inertia by allocating the peripheral weight, for example, a metal base is provided on the sole surface side of the head, etc. Some have a structure in which a weight body made of a dissimilar metal such as tungsten (W) having a higher specific gravity than a material is integrally joined.

[0003]

However, in such a method of manufacturing an iron club having a conventional structure, since the head is formed by casting or forging, the material density is 100%. It is difficult to manufacture enough to satisfy the excellent shot feeling and hitting sound, and because of the restrictions on the mold and manufacturing method, the degree of freedom such as the head shape and wall thickness is low, and the dimensions are small. Post-processing such as grinding and polishing for adjusting the precision and weight precision is required, and the production cost is high and the quality is not stabilized.

Conventionally, it is not possible to join and integrate different kinds of metals as a weight body at the same time as the head is formed, and it is impossible with current manufacturing techniques such as melting. At present, the joining is performed separately, which not only complicates the molding process and increases the manufacturing cost, but also includes a head made of titanium or a titanium alloy as a metal base material and tungsten. Joining with the weight body could not be performed well by welding or the like.

Further, conventionally, for example, Japanese Patent Laid-Open No. 6-23075
As disclosed in Japanese Unexamined Patent Publication, an invention has been proposed in which an iron club head is manufactured by metal powder injection molding means.

However, according to this prior art manufacturing method, when a head green body is injection-molded with a head molding material made of a powdered material of titanium or a titanium alloy, the head molding material is filled into a cavity of a molding die. Before performing the sintering of the head green body by heat treatment, a bulk material of a different metal having a high specific gravity, such as tungsten, pre-shaped as a weight body is installed in the cavity of the molding die. , The weight does not shrink,
Because the outer titanium or titanium alloy shrinks due to sintering,
Defects such as cracks and cracks are likely to occur at the boundaries between these joints, so that quality cannot be stabilized.

An object of the present invention is to simplify a molding process,
It is an object of the present invention to provide a method of manufacturing a golf club head capable of reducing manufacturing costs and stabilizing quality.

[0008]

In order to solve the above-mentioned problems, the present invention forms a head with a desired metal base material, and the head is made of a dissimilar metal having a higher specific gravity than the metal base material. In manufacturing a golf club head obtained by joining and integrating a weight body, a head molding material comprising a powder material of a metal base material forming the head in a cavity of a molding die having a predetermined head outer shape. At the same time, a head green body is injection-molded by filling a heavy body forming material comprising a powder material of a dissimilar metal forming the weight body by two-color molding or the like, and the head green body is subjected to heat treatment and sintered. It is characterized by becoming.

In this case, the weight forming material forming the weight has the same thermal expansion coefficient as that of the metal base material forming the head, or 0.8 to 1.2 times. If the dissimilar metal is composed of a powder raw material and the material for forming a weight body is a powder raw material having a thermal expansion coefficient close to ± 20% of the thermal expansion coefficient of the head metal base material, At the time of the heat treatment, it is possible to prevent the occurrence of cracks, cracks, and the like at the boundary portion of the joining portion as before due to the relationship between the heat shrinkage and the sintering shrinkage.

As the head metal base material, titanium or titanium alloy is preferably used, and as the dissimilar metal of the weight body, tungsten or tungsten alloy is preferably used.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. As shown in FIG. Golf club, for example, the head of an iron club.

The head 1 is made of a metal base material such as titanium or a titanium alloy and has a material density of 90% or more.
The hitting portion 2 and the hosel portion 3 set to less than 00% are integrally formed, and as shown in FIG. 2, the face surface 2a of the hitting portion 2 has a loft angle θ corresponding to each count, The back surface 2b side has a cavity shape formed by the formation of the concave portion 4, and the sole surface 2c side is formed to have a relatively wide and thick bulge.

A weight 5 is integrally buried and joined to the sole surface 2c side of the head 1, and the weight 5 is made of a metal base material such as titanium or a titanium alloy forming the head 1. Dissimilar metals having the same coefficient of thermal expansion or a coefficient of thermal expansion close to within ± 20% (a coefficient of thermal expansion of 0.8 to 1.2 times the coefficient of thermal expansion of the metal base material) and a higher specific gravity, for example, It is made of tungsten or a tungsten alloy.

By the way, the metal powder injection molding method is a method of granulating a kneaded material obtained by adding a binder such as water wax or resin to a fine metal powder material of, for example, 1 to 600 μm, preferably about 1 to 100 μm. Granulating and pelletizing with a machine, supplying the pelletized molding material to an injection molding machine, fluidizing, and injecting and filling into a cavity of a molding die having a desired outer shape of a molded product. By molding a head green body having a desired product shape, heat treating the head green body to remove the binder, and sintering the head brown body after removing the binder to form a molded product. It is.

In this case, the head green body refers to a form in which the metal powder, binder, and moisture after injection molding are easily deformed and are in an unstable state, and the head brown body refers to the head green body. A form in which the body is heated and dried to remove water and is in a shape stable state.

That is, in order to manufacture the above-described head 1, as shown in FIG. 3, a titanium or titanium alloy or the like forming the head 1 is formed in a cavity 11 of a molding die 10 having a desired head outer shape. At the same time as the filling of the head forming material 21 composed of the powder raw material of the metal base material, the weight forming material 22 composed of the powder raw material of a dissimilar metal such as tungsten or a tungsten alloy forming the weight 5 is filled. Head green body 20 by two-color molding etc.
Is injection molded.

Next, the head green body 20 is subjected to a heat treatment, and after sintering after removing the binder, FIG.
And a completed product of the head 1 as shown in FIG.

In this case, in order to enhance the sinterability of the head green body 20, a powder having a small particle diameter is usually used as a powder raw material for the head molding material 21. As the raw material cost increases as the particle size becomes smaller, for example, a large particle size powder having a particle size of 100 μm or more is mixed with a small particle size powder having a particle size ratio of about 1/7 to the large particle size powder. If used, it is possible to fill the gaps between the large particle size powders with the small particle size powder, so that the sinterability of the head green body 20 during heat treatment is not reduced, thereby reducing the cost of the powder raw material. The cost of the whole head can be reduced by the down.

Moreover, the molded head 1 has a porous structure containing ultra-fine bubbles therein, and the material density thereof can be easily controlled in the range of 90% or more and less than 100%. Therefore, at the time of hitting the ball, the elastic wave generated in the hitting portion is scattered by the minute microbubbles, interferes and is attenuated, whereby a hitting sound having a soft hitting feeling and a high clear tone can be obtained.

In the above-described embodiment, titanium (Ti) or a titanium alloy is used as a metal base material for forming the head 1 and tungsten (W) or a dissimilar metal such as a tungsten alloy is used as the weight 5. For example, iron (Fe) or an iron alloy or stainless steel (SUS) is preferably used as a metal base material of the head 1, and nickel (Ni) or a nickel alloy, a die steel, a high-speed steel or a super-hard alloy is preferably used as the weight body 5 of a different metal. Used for

Although the golf club has been described using an iron club as an example, the present invention can be applied to a wood club, a putter club, and the like.

[0022]

As is apparent from the above description, according to the present invention, when a head is manufactured by means of metal powder injection molding, the head is formed in a cavity of a molding die having a predetermined head outer shape. At the same time as filling the head molding material composed of the powder raw material of the metal base material, the heavy body molding material composed of the powdered material of the dissimilar metal having a higher specific gravity than the metal base material of the head is filled as a weight body by two-color molding or the like. Since the head green body is injection-molded and heat-treated to the head green body, the joining of the weight body can be performed simultaneously with the head molding in one step.
Since the molding process can be simplified, the manufacturing cost can be reduced, and the degree of freedom of the head shape and thickness is increased, and post-processing such as grinding and polishing as before is required. The dimensional accuracy and the weight accuracy can be improved without performing.

Further, the material for molding the weight body has the same thermal expansion coefficient as the metal base material of the head, or a thermal expansion coefficient of 0.8 to 1.2 times the thermal expansion coefficient of the metal base material (within ± 20%). Since it is made of a powdered material of a dissimilar metal having a similar thermal expansion coefficient), it is possible to prevent the occurrence of defects such as cracks and cracks at the boundary between the joints due to the thermal contraction of the weight during conventional heat treatment. It can maintain the quality stabilization.

Further, since the head is manufactured by means of metal powder injection molding, it is easy to manufacture an alloy having a head shape which cannot be obtained by using a conventional ingot.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an iron club head as an embodiment manufactured by a method of manufacturing a golf club head according to the present invention.

FIG. 2 is a sectional view of the same.

FIG. 3 is an explanatory view showing a head molding state by the same metal powder injection molding means.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Head, 2 ... Hitting part, 2a ... Face surface, 2b ... Back surface, 2c ... Sole surface, 3 ... Hosel part, 5 ... Weight body, 10. ··· Molding die, 11: cavity, 20: head green body, 21: head molding material, 22: heavy body molding material.

Claims (4)

[Claims] 1. A method of manufacturing a golf club head in which a head is formed from a desired metal base material, and a weight body made of a dissimilar metal having a higher specific gravity than the metal base material is joined to and integrated with the head. Filling a cavity of a molding die having a predetermined head outer shape with a head molding material composed of a powder raw material of a metal base material forming the head, and at the same time, using a powder raw material of a dissimilar metal forming the weight body A method of manufacturing a golf club head, characterized by filling a material for molding a heavy body into a head green body, injection molding the head green body, and subjecting the head green body to heat treatment and sintering. 2. A material for forming a weight body is made of a powdered material of a dissimilar metal having a thermal expansion coefficient of 0.8 to 1.2 times the thermal expansion coefficient of a metal base material forming a head. The method of manufacturing a golf club head according to claim 1. 3. The golf club head manufacturing method according to claim 1, wherein titanium or a titanium alloy is used as a metal base material for forming the head. 4. The golf club head manufacturing method according to claim 1, wherein tungsten or a tungsten alloy is used as the dissimilar metal forming the weight body.