JP2000334073A - Golf club head and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a golf club of good appearance resembling popularly used golf club heads in shape and size, requiring less production steps by avoiding cutting process of the joint portion of constituents of the golf club head. SOLUTION: The head comprises a center core portion 1 (a first member) consisting of material of high specific gravity and a material of specific gravity lower than the core. An assemblage 4 of center core material 1 and a preformed wrapping member 2 is arranged in a cavity 6 of a die 5. A composition 10 comprising a binder consisting of agar and water, metal powders having specific gravity lower than the material used for core 1, and a kind of powder selected from ceramic powder and these mixture, are injected into the cavity 6 in the die 5. A green body is formed, from which water is eliminated and is subjected to sintering.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a solid metal head having a low center of gravity of a golf club using a metal powder injection molding method and a golf club head using this method. Is improved.

[0002]

2. Description of the Related Art In recent years, various types of golf clubs have been commercialized from new shapes and new materials. Under these circumstances, the trend of golf clubs having a head with a low center of gravity is remarkable. Golf club heads with a low center of gravity are widely used in irons and the like, and by lowering the center of gravity of the head, when a user hits the ball, the lower end of the face can easily be sunk into the ball below, so that the ball It is easy to get up and hit. Most of such golf club heads having a low center of gravity are solid metal heads, and are generally constituted by a core portion and a peripheral portion surrounding the core portion. The core portion is made of a metal having a high specific gravity, such as a tungsten copper alloy or tungsten, to have a low center of gravity. The peripheral portion is made of titanium, stainless steel or the like having a lower specific gravity than the material forming the core portion. By the way, in order to obtain a golf club head having a lower center of gravity, it is desirable that the above-mentioned peripheral portion is composed only of titanium having a lower specific gravity than stainless steel, but since titanium is difficult to process, a titanium plate is embedded in the face portion, and The part is made of easy-to-machine stainless steel.

[0003] In a conventional method of manufacturing a solid metal head having a low center of gravity, a method of embedding a core portion in a peripheral portion is shown in FIG.
As shown in FIG. 7, the peripheral portion 30 is divided into a part of the back face portion, a first peripheral member 31 serving as the face portion, and a second peripheral member 32 serving as the remaining portion of the back face portion. The core 33 is disposed between the first and second peripheral members 31, 32, and the first and second peripheral members 31, 3 are arranged.
8, a hole 35 for driving the core portion 33 into the peripheral portion 30 as shown in FIG. 8, and a driving method for driving the core portion 33 into the hole 35,
As shown in FIG. 9, a wide insertion opening 36 for inserting the core portion 33 in the peripheral portion 30 is formed, and after inserting the core portion 33 from the insertion hole 36, the peripheral portion 30 is swaged. A caulking method for narrowing the opening of the insertion port 36 or a casting method has been used.

[0004]

However, in the conventional method of manufacturing a solid golf club head, the welding method welds the peripheral members 31 and 32, so that the surface finish of the joint is not good and the joint is finished by grinding. Processing was required, the number of manufacturing steps increased, and productivity was poor.
Further, the metal head obtained by any of the driving method, the caulking method, and the casting method had an exposed central core, and was unsightly. Further, in the conventional manufacturing method of a golf club head, there is a golf club head having a large head shape, becoming a unique club and losing portability. Therefore, an object of the present invention is to eliminate the step of grinding the joints of the components of the golf club head, thereby reducing the number of manufacturing steps.
It is an object of the present invention to provide a method of manufacturing a golf club head having a good appearance and obtaining a golf club head having a shape and dimensions similar to those of a commonly used golf club head.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a solid golf club head having a first member made of a material having a high specific gravity and a second member made of a material having a lower specific gravity than the material forming the first member. The method of, metal, ceramic and a first member made of a kind of high specific gravity material selected from a mixture thereof, a metal having a lower specific gravity than the material forming the first member,
A wrapping member made of a kind of material selected from ceramic and a mixture thereof and wrapping the first member is separately molded in advance, and then the first member and the wrapping member are combined in a cavity of a mold. After arranging in a state, a molding binder consisting of agar and water, a metal powder having a lower specific gravity than the high specific gravity material used in the first member, a kind of powder selected from ceramic powder and a mixed powder thereof and A molding composition containing the compound is injected into a cavity of the mold to form a solid green body, and the green body is sintered after removing at least water from the green body. Solvable. In the method of manufacturing a golf club head having the above-described configuration, as the wrapping member, one having an opening for inserting the first member is used, and the opening of the wrapping member is closed by injection molding of the molding composition. Is preferable.

For the first member, a molding composition containing a molding binder composed of agar and water and a kind of powder selected from a metal powder, a ceramic powder and a mixed powder thereof having a high specific gravity is used. It is preferable to mold it. The wrapping member, a molding binder consisting of agar and water, a metal powder having a lower specific gravity than the high specific gravity material used in the first member, a type of powder selected from ceramic powder and a mixed powder thereof. It is preferable to mold using the contained molding composition. Further, when injecting the molding composition into the cavity, it is preferable to inject from the side of the golf club head that will become the sole portion. Also,
As the agar contained in the molding binder, it is preferable to use an agar having an average molecular weight of 30,000 to 150,000, an agar concentration of 4% and a gel strength of 200 to 480 g / cm ² .

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG.
This will be described in detail with reference to FIGS. In the golf club head manufacturing method of the present invention, a molding composition as described below is suitably used. The molding composition used in the present invention includes a molding binder (hereinafter, a binder) composed of agar and water, and a kind of powder (hereinafter, a metal / ceramic) selected from a metal powder, a ceramic powder, and a mixed powder thereof. Powders). As the agar contained in the binder, it is preferable to use those having an average molecular weight of 30,000 to 150,000, an agar concentration of 4% and a gel strength of 200 to 480 g / cm ² .

Agar is a substance extracted from seaweed, which is generally called "agar". The main component is agarose, and the other impurities are collectively called agaropectin. Agar is soluble in warm water and its aqueous solution is 90-96.
It becomes a sol-like viscous liquid at a temperature of 35 ° C., and when cooled to a temperature of 35 to 45 ° C. or lower, it gels and contracts in volume to become an elastic fixed substance. The gel point and sol point are not significantly affected by the concentration of agar. The gel strength of agar when the agar powder is dissolved in water changes depending on the type of seaweed, the combination thereof, or the extraction method. When the average molecular weight of the agar contained in the binder is smaller than 30,000, the strength of the obtained green body is low, and the shape retention is deteriorated.
The dimensional stability of the sintered body deteriorates. On the other hand, if it is larger than 150,000, the decomposability deteriorates, the sintering density does not increase, and the mechanical strength decreases. The gel strength of agar is 200
g / cm ² less than the resulting green body strength is low,
The shape retention becomes poor, and the dimensional stability of the sintered body becomes poor. On the other hand, if it is more than 480 g / cm ² , the decomposability deteriorates, the sintering density does not increase, and the mechanical strength decreases.

[0009] The binder used in the present invention is obtained by dissolving agar in water.
15 to 35 parts of agar per part (parts by weight, hereinafter the same)
Preferably, 20 to 30 parts are dissolved. If the content of agar is less than 15 parts, the effect of binding the metal powder cannot be obtained, and if it exceeds 35 parts, the viscosity in the sol state becomes too high, and kneading becomes difficult. Also, in the binder,
Further, alcohols may be added. As the alcohols, one kind or a mixture of two or more kinds such as ethanol, methanol, isopropyl alcohol, and 2,3-dibromopropanol is used. The alcohols increase the gel strength of the agar in the gel state. When adding alcohols, add 100
It is preferable to use 5 to 30 parts of alcohols per part. If the alcohol content is less than 5 parts, the effect of increasing the gel strength is insufficient, and if it exceeds 30 parts, the gel strength starts to decrease.

Alternatively, a water-soluble polymer may be added to a binder consisting of agar and water or a binder consisting of agar, water and alcohols. Examples of the water-soluble polymer include polyethylene glycol, polyvinyl alcohol, carboxymethyl cellulose and the like, with polyethylene glycol being preferred. This water-soluble polymer gives viscosity to the binder gel,
Improve the flowability of the injection material during injection molding and improve the separation of the binder and metal powder. When a water-soluble polymer is added, water-soluble polymer 5 is added to 100 parts of water.
Preferably, 10 parts are used. If the amount of the water-soluble polymer is less than 5 parts, the effect of addition cannot be obtained. If the amount exceeds 10 parts, the viscosity of the sol increases, which is inconvenient.

If necessary, benzoic acid, sodium benzoate, formic acid, etc. as preservatives, stearic acid, erucic acid, metal soap dispersants of higher fatty acids, surfactants, etc. as lubricants at the time of injection molding may be used. Can be added. Further, sodium borate for increasing the viscosity of the sol and the strength of the gel in the aqueous agar solution may be added.

The binder used in the present invention is prepared by adding agar, and if necessary, alcohols, water-soluble polymers and other additives to warm water heated to 90 to 96 ° C., preferably at a temperature of 100 to 120. ° C, vapor pressure 1.0 ~
It can be prepared by well stirring, mixing and dissolving under a pressure of 2.0 atm.

In the present invention, the metal powder used as a raw material is an iron, stainless steel or other steel obtained by a gas atomization method, a water atomization method, a high-pressure water atomization method or the like, an average particle size of nickel, tungsten copper alloy, tungsten or the like. Diameter 1 to 200 μm, preferably 100 μm
In the following, more preferably, spherical or true spherical fine powder having a size of 20 μm or less, which is surface-treated with a coupling agent described below is preferable. Also, a core portion (first member) described later.
When preparing a molding composition for molding, as the metal powder, tungsten copper alloy, tungsten,
A high specific gravity metal powder such as nickel having a specific gravity in the range of 14 to 19 is used, and a tungsten powder is particularly preferably used.

Further, a molding composition for molding a wrapping member for wrapping the core portion (composition composition for the wrapping member), and a portion other than the core portion and the wrapping member (a hosel portion and a face) Part), when preparing a molding composition for molding (third molding composition), as the metal powder, titanium, titanium alloy, iron, steel such as stainless steel, aluminum alloy and the like When a metal powder having a lower specific gravity than the high specific gravity metal powder used for the core is used, and when tungsten is used as the material forming the core, titanium is preferably used. Used. Metal powders having an average particle size smaller than 1 μm are not preferred because they are difficult to produce and the production cost is high. On the other hand, if the average particle size is larger than 200 μm, the binder and the metal powder may be separated by the shearing force during injection molding, and molding may not be performed. The low specific gravity powders used in the molding composition of the wrapping member and the third molding composition may be of the same type or different types, and the characteristics of the desired golf club head Is appropriately selected and used.

The coupling agent hydrolyzes to form a hydroxyl group, and has both a group capable of interacting with the metal powder and an organic functional group capable of interacting with the polysaccharide in the binder. Include an amino group (—NH ₂ ), a sulfo group (—SO ₃ H), and an amide group (—N
A titanate-based coupling agent or a silane coupling agent having at least one of HCO-) and a hydroxyl group (-OH) is preferably used. As the titanate-based coupling agent, for example, isopropyl- represented by the following chemical formula (1) is used.
Trianthranyl titanate, isopropyl-tri (N-aminoethyl-aminoethyl) titanate represented by the following chemical formula (2), tetraisopropyl-di (dilauryl phosphite) titanate represented by the following chemical formula (3), and the following chemical formula (4) 4-aminobenzenesulfonyl-
Dodecylbenzenesulfonyl-oxyacetate titanate; Examples of the silane coupling agent include γ- (2-aminoethyl) aminopropyltrimethoxysilane represented by the following chemical formula (5).

[0016]

Embedded image

[0017]

Embedded image

The amount of the coupling agent added is preferably 0.5 to 3% per unit volume of the metal powder. If the amount of the coupling agent is less than this, the effect of addition cannot be obtained, and if it is more than this, the effect of addition does not change.

The surface treatment method of the metal powder includes a wet treatment method,
There are two dry processing methods. In the wet treatment method, untreated metal powder is added to a dispersion of a coupling agent in a large amount of water, followed by stirring. Then, after leaving at room temperature for about 10 to 30 minutes, it is heated and dried at a temperature of about 105 ° C. for 10 hours or more to obtain a surface-treated metal powder. In the dry treatment method, the coupling agent is gradually added while the untreated metal powder is stirred at a high speed by a high-speed mixer such as a Henschel mixer (trade name), and further heated to a temperature of 60 to 80 ° C. At a high speed of about 1500 rpm
This is a method of obtaining a surface-treated metal powder by stirring for about 10 minutes. This method can be preferably used particularly when the average particle diameter of the raw metal powder is relatively large, about 10 to 200 μm.

When the metal powder is subjected to the above-described surface treatment with the coupling agent, the affinity between the metal powder and the binder is improved through the coupling agent, and thus the wettability between the metal powder and the binder is improved. , And the adhesion is significantly improved. In particular, when the particle size of the metal powder is as large as 10 μm or more, the effect of improving the adhesiveness between the metal powder and the binder is great, and metal injection molding using large metal powder having a particle size of about 200 μm becomes possible. Further, since the affinity between the metal powder and the binder is increased, it is possible to reduce the mixing ratio of the binder in the molding composition and increase the mixing amount of the metal powder. Therefore, the sintering density of the obtained compact can be increased, and the accuracy after sintering can also be improved.

In the present invention, as the ceramic powder used as a raw material, oxides, borides, nitrides, silicides and carbides of various metals, non-metals or mixtures thereof, and mixtures thereof are used. Also,
When preparing a molding composition (molding composition for the core portion) for molding the core portion (first member), a ceramic powder having a high specific gravity among the above ceramic powders is used. Can be Further, a molding composition for molding a wrapping member for wrapping the core portion (composition for molding the wrapping member) and a molding composition for molding portions other than the core portion and the wrapping member. When a product (third molding composition) is prepared, a ceramic powder having a lower specific gravity than the high specific gravity ceramic powder used for the core is used.

In order to perform molding, first, a kind of powder selected from a metal powder, a ceramic powder and a mixed powder thereof is added to the binder and kneaded to obtain a molding composition. The face part and hosel part are molded by the MIM method by using, before the molding composition is injected into the cavity of the mold, the powder is added to the binder in advance, kneaded, and granulated. Pellets are used. Also, the core and the wrapping member
Although it can be molded by the M method, in that case, before injecting the molding composition for the core portion and the molding composition for the wrapping member into the core portion molding die and the wrapping member molding die, A powder obtained by adding the above powder to the above binder, kneading, granulating, and pelletizing is used.

In the kneading, a kneading apparatus is used at a temperature of 100 to 120 ° C. and a vapor pressure of 1.0 to 2.0 at.
By performing kneading while pressurizing to m, kneading properties can be improved. If the temperature during kneading is lower than 100 ° C., the effect of improving kneading properties cannot be obtained, and if it is higher than 120 ° C., agar is gradually decomposed and gelling ability is lost, which is not preferable. If the pressure during kneading is lower than 1.0 atm, the effect of improving kneading properties cannot be obtained, and the vapor pressure is 2.0 a.
If it is higher than tm, agar is gradually decomposed and loses its gelling ability, which is not preferable. By performing the kneading of the metal / ceramic powder and the binder at a high temperature and in a pressurized state, the kneading property can be improved, and the mixing ratio of the metal / ceramic powder to the binder can be increased. Accordingly, the sintering density of the golf club head can be increased, and the mechanical strength can be improved.

The mixing ratio of the metal / ceramic powder and the binder is such that the ratio of the metal / ceramic powder in the molding composition is 35 to 70% by volume, preferably 40 to 6%.
0% by volume, more preferably 55% by volume. In addition, during kneading, it is preferable to add the metal / ceramic powder in several portions. If the proportion of the metal / ceramic powder is less than 35% by volume, the sintered density of the golf club head obtained after sintering becomes low, so that it is not preferable.
% Or more by volume is more preferable. If the ratio of the metal / ceramic powder exceeds 70% by volume, it becomes difficult to uniformly knead the powder, and to obtain a good kneaded state, the volume is more preferably 65% by volume or less.

After the molding composition is prepared, as shown in FIG. 1, a core (first member) 1 made of a material having a high specific gravity of a solid metal head, and a core having a specific gravity lower than that of the core 1 A wrapping member 2 made of a material and wrapping the core portion 1 is separately formed in advance. The shape of the wrapping member 2 is roughly the shape of a portion excluding the hosel portion and the face portion of the golf club head, and the surface on the side to be the face portion has a housing for housing the center core portion 1. A concave portion 2a is formed, and a concave portion (not shown) that is a concave portion called a cavity is formed on the surface on the side that becomes the back face portion. The wrapping member 2 is such that the core 1 is exposed from the opening when the core 1 is fitted through the opening of the storage recess 2a.

Here, as a method for molding the core portion 1, the composition for molding the core portion is injection-molded into a cavity of a mold (not shown) for molding the core portion. Here, the injection temperature is set to 80 ° C. or higher for keeping the binder in a sol state. Next, the core part 1 in the mold is cooled to room temperature,
The binder is in a gel state and its shape is maintained. Thereafter, when the mold is released, the core portion 1 is obtained. On the other hand, as a method of molding the wrapping member 2, the molding composition for the wrapping member is injection-molded into a cavity of a wrapping member molding die (not shown). The injection temperature here is
The binder is kept at 80 ° C. or higher to maintain the sol state. Next, the wrapping member 2 in the mold is cooled to room temperature,
The binder is in a gel state and its shape is maintained. Thereafter, when the mold is released, the wrapping member 2 is obtained. The core portion 1 and the wrapping member 2 are made of a molding binder containing the above-mentioned molding binder composed of agar and water and a kind of powder selected from a metal powder, a ceramic powder and a mixed powder thereof. It may be formed by a method other than the injection molding method using the composition.

Next, as shown in FIGS. 2 and 3, a mold (combination) 4 in which the core portion 1 is fitted and fitted into the storage recess 2 a of the wrapping member 2 is arranged in a mold 5. The mold 5 used here has a cavity 6 in which the shape of the outer shape of the golf club head is previously hollowed inside. The combination 4 is arranged inside the cavity 6, and at this time, a gap 7 is provided between the combination 4 and the cavity 6. That is, there is a gap 7 around the combination 4 arranged in the cavity 6. The sizes of the core 1, the enclosing member 2, the cavity 6, and the gap 7 are appropriately determined in consideration of the size of the completed club head, the size and thickness of the first member, and the like.

Next, the third molding composition 10 is injection-molded into the gap 7 in the cavity 6 by using an injection device or the like, and the molding composition 10 exposes the core portion 1 of the enclosing member 2. A solid green body is obtained by covering the opening and forming a portion to be a face portion and a hosel portion. The mold 5 at the time of the injection molding here is 35-35 so that the binder of the third molding composition 10 keeps the sol state.
It is heated to about 50 ° C. Here, the molding composition 10
When injecting into the cavity 6, it is preferable to inject from the gate 9 formed on the part to be the sole part of the golf club head, and more preferably to the part to be the sole part and the part to be the face part It is preferable to inject from a position near the side.

Next, by cooling the mold 5 to a temperature of 30 ° C. or less, the binder of the third molding composition 10 becomes a gel, and the shape of the green body is maintained.
FIG. 4 is a view showing an injection streamline 10a when the third molding composition 10 is injected to form portions to be the hosel portion and the face portion of the golf club head. In addition,
The trajectory of the injection streamline 10a when forming the hosel portion and the face portion of the golf club head shown in FIG. 4 is an example, and the position of the streamline differs depending on the injection molding conditions. Thereafter, after removing the green body from the mold 5, the green body is debindered, and water derived from the binder,
Removes alcohol, agar, and some water-soluble polymers. During this removal, it is also possible to remove only water and shift to sintering.

There are various methods for removing the binder.
Remove water and alcohols at ~ 150 ° C and add 200
Heating to ~ 400 ° C to thermally decompose and remove part of the agar and water-soluble polymer, or freeze-drying or vacuum-drying the green body, and keeping most of the water while keeping the binder in a gel state A method of removing alcohols and then heating to remove agar and a part of the water-soluble polymer is preferable, and the latter method is particularly preferable in that cracking and cracking of the green body can be prevented. Further, it is desirable that the debinding is performed in a vacuum or an inert gas atmosphere to prevent oxidation of the metal powder. By this binder removal, the water content of the green body becomes 0.01 to 0.1% by weight. The brown body obtained by removing the binder from the green body can be easily subjected to processing such as grinding for removing burrs and the like.

Next, the decolorized brown body is heated in a heating furnace and sintered to obtain a solid golf club head having a desired shape. The heating is performed by raising the temperature to about 1100 to 1500 ° C. in a vacuum or an inert gas atmosphere. Next, as shown in FIG. 5, the golf club head is gradually cooled and released from the mold, and as shown in FIG. 5, a core 1 made of a material having a high specific gravity selected from metals, ceramics, and a mixture thereof. Thus, a solid golf club head having the second member 15 made of one kind of material selected from metals, ceramics, and mixtures thereof having a lower specific gravity than the material of (1) is obtained. The second member 15 is a portion other than the core portion 1 and is a portion (a hosel portion and a face portion) formed by using the wrapping member 2 and the third molding composition 10. In FIG. 5, reference numeral 20 denotes a hosel part, 21
Is a back face portion, 22 is a face portion, 23 is a sole portion, and 24 is a concave portion 24 called a cavity formed in the back face portion 21.

In the golf club head obtained as described above, the opening of the enclosing member 2 is selected from the low specific gravity metals, ceramics and mixtures thereof contained in the third molding composition 10. The core 1 is not exposed because it is covered with a kind of material. The hosel portion 20 and the face portion 22 of the golf club head obtained as described above have a flow direction of the third molding composition 10 by injection for closing the opening of the wrapping member 2 as shown in FIG. The trajectory of the streamline 10a along the line remains. The trajectory of the streamline 10a of the hosel portion 20 is a spiral streak, and the trajectory of the streamline 10a at the corner of the face portion 22 is a short streak. The trajectory of the streamline 10a of the hosel part 20 and the face part 22 shown in FIG. 6 is an example, and the position where the trajectory of the streamline is left differs depending on the injection molding conditions.

In the method of manufacturing the golf club head according to the embodiment, a combination 4 of the core portion 1 and the wrapping member 2 separately formed in advance is arranged in the cavity 6 of the mold 5 and a third molding composition is formed. The object 10 can be manufactured into a solid green body by injection molding in the cavity 6 of the mold 5 and sintering after removing at least water from the green body. Further, only by injection-molding the molding composition 10 into the cavity 6 of the mold in which the combination 4 is disposed, the portion (the hosel portion 20 and the face portion 22) formed by the molding composition 10 is wrapped. Since the member 2 can be integrally formed to form the second member 15 around the core portion 1, the peripheral members around the core portion as in the conventional golf club head manufacturing method can be formed by welding or surrounding. There is no need for a step of finishing the joint of the members by grinding. Further, in the golf club head obtained in the present embodiment, since the center portion 1 is surrounded by the second member 15, it is not exposed to the outside and has a good appearance. Furthermore, since the golf club head obtained in the present embodiment can keep the sole width W at about 21 mm or less, the head shape becomes large as obtained by a conventional golf club head manufacturing method. Without
It is portable.

Also, since a binder comprising low gel strength, low molecular weight agar and water is used as a binder contained in the molding composition, the binder has good thermal decomposability, and therefore has a good Has less residual carbon and oxygen than before, and the mechanical strength of the obtained golf club head is improved. Also, since the binder has good decomposability, a high sintering density can be obtained. Furthermore, when injecting the third molding composition 10 into the cavity, a golf club head having excellent mechanical strength can be manufactured by injecting the third molding composition 10 from the side to be the sole portion 23 of the golf club head. Therefore, according to the golf club head manufacturing method of the present embodiment, the manufacturing process can be reduced by eliminating the step of grinding the joints of the components of the golf club head, and the appearance is good, the mechanical strength is excellent, and the shape is excellent. A solid golf club head having dimensions and dimensions similar to those of a commonly used golf club head can be manufactured.

The golf club head obtained by the method of manufacturing a golf club head according to the present embodiment does not have an exposed core portion, has a good appearance, has excellent mechanical strength, and has good shape and dimensions. It is similar to a golf club head normally used, and has versatility. In addition, the core 1 is made of tungsten, and the wrapping member 2 is used.
By using titanium as a, by using titanium as a low specific gravity powder of the third molding composition 10,
A golf club head including the core portion 1 made of tungsten and the second member 15 (back face portion 21, face portion 22, and hosel portion 20) made of titanium is obtained. This golf club head has an advantage that the center of gravity is lower, the lower end of the face can easily be sunk into the ball when the user hits the ball, and the hitting performance is further improved. In the above embodiment,
I explained the case of manufacturing iron heads,
The present invention is also applicable to a golf club head having a low center of gravity in which a weight member such as a putter head is embedded.

[0036]

As described above, in the method of manufacturing a golf club head according to the present invention, the first member and the wrapping member separately formed in advance are arranged in the cavity of the mold in a state where they are combined.
Molding composition containing a molding binder composed of agar and water, and a kind of powder selected from a metal powder having a lower specific gravity than the material having a higher specific gravity used in the first member, a ceramic powder, and a mixed powder thereof. The object is injection molded into the cavity of the mold to form a solid green body, and after sintering after removing at least water from the green body, a grinding step of a joint portion of the components of the golf club head is performed. Thus, the manufacturing process can be reduced, and a solid golf club head having good appearance, excellent mechanical strength, and shape and dimensions similar to those of a golf club head generally used can be manufactured.

The binder contained in the molding composition has an average molecular weight of 30,000 to 150,000.
0, the gel strength is 200-480 g / cm at 4% agar concentration
By using the agar of ² and water, the binder has good thermal decomposability, so that the residual carbon and oxygen after sintering are smaller than before, and the mechanical strength of the obtained golf club head is lower. improves. Also, since the binder has good decomposability, a high sintering density can be obtained.
Further, when injecting the molding composition into the cavity,
A golf club head having excellent mechanical strength can be manufactured by injecting the golf club head from a portion to be a sole portion of the golf club head.

The golf club head obtained by the method of manufacturing a golf club head according to the present invention does not expose the first member, has good appearance, has excellent mechanical strength, and has good shape and dimensions. It is similar to a golf club head normally used, and has versatility. Further, by using a material made of tungsten as the first member (core portion), using a material made of titanium as the wrapping member, and using titanium as a powder having a low specific gravity of the molding composition to be injected, the material is made of tungsten. A golf club head comprising a first member made of titanium and a second member made of titanium (a back face, a face portion, and a hosel portion) is obtained, and the golf club head thus obtained is
Since the center of gravity is lower, even a beginner has the advantage that the lower end of the face can be easily sunk into the lower part of the ball when hitting the ball, the ball can be easily lifted, and the ease of hitting can be further improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a core portion (first member) and a wrapping member used in a method of manufacturing a golf club head according to an embodiment of the present invention.

FIG. 2 is an explanatory view of one process of the manufacturing method according to the embodiment of the present invention, in which a core portion and a wrapping member are combined and arranged in a cavity of a mold.

FIG. 3 is a sectional view taken along line III-III of FIG. 2;

FIG. 4 is a view showing an injection streamline when a molding composition is injected to form a hosel portion and a face portion of a golf club head in the embodiment of the present invention.

FIG. 5 is a perspective view showing a golf club head obtained by an embodiment of the manufacturing method of the present invention.

FIG. 6 is a view showing a locus of streamlines along a flow direction of a molding composition possessed by a hosel portion and a face portion of a golf club head obtained by an embodiment of the manufacturing method of the present invention.

FIG. 7 is a view showing an example of a method of embedding a core portion in a peripheral portion in a conventional method of manufacturing a solid metal head having a low center of gravity.

FIG. 8 is a view showing another example of a method of embedding a core portion in a peripheral portion in a conventional method of manufacturing a solid metal head having a low center of gravity.

FIG. 9 is a view showing another example of a method of embedding a core portion in a peripheral portion in a conventional method of manufacturing a solid metal head having a low center of gravity.

[Explanation of symbols]

Reference numeral 1: core part (first member), 2: wrapping member, 2a ...
Storage recess, 4 combination, 5 mold, 6 cavity, 7 gap, 9 gate, 10 molding composition, 10a flow Line 15, 15 second member, 20 hosel part, 21 back face part, 22 face part, 23 sole part, 24 concave part (cavity), W
... Sole width.

Claims (9)

[Claims] 1. A method for manufacturing a solid golf club head comprising: a first member made of a material having a high specific gravity; and a second member made of a material having a lower specific gravity than the material forming the first member. A first member made of a material having a high specific gravity selected from ceramics and a mixture thereof, and a metal having a lower specific gravity than the material forming the first member, made of a material selected from a ceramic and a mixture thereof, A wrapping member for wrapping the first member is separately formed in advance, and then the first member and the wrapping member are arranged in a cavity of a mold in a state where the first member and the wrapping member are aligned, and then a molding binder made of agar and water is formed. A molding composition containing a metal powder having a lower specific gravity than the material having a high specific gravity used for the first member, a ceramic powder, and a powder selected from a mixture thereof. The solid green body by injection molding into the tee, preparation of the golf club head, characterized in that the sintered after removing at least water from the green body. 2. The method according to claim 1, wherein the wrapping member has an opening through which the first member is inserted, and the opening of the wrapping member is closed by injection molding of the molding composition. The manufacturing method of the golf club head described in the above. 3. The method according to claim 1, wherein the molding composition comprises a molding binder comprising agar and water and a powder selected from a metal powder, a ceramic powder, and a mixed powder thereof having a high specific gravity. The method for manufacturing a golf club head according to claim 1, wherein the member is formed. 4. A molding binder comprising agar and water, and a kind of powder selected from a metal powder, a ceramic powder and a mixed powder thereof having a lower specific gravity than the high specific gravity material used for the first member. The method for manufacturing a golf club head according to any one of claims 1 to 3, wherein the enclosing member is molded using a molding composition contained therein. 5. The golf club according to claim 1, wherein when the molding composition is injected into the cavity, the injection is performed from the side of a sole portion of the golf club head. Head manufacturing method. 6. The agar contained in the molding binder has an average molecular weight of 30,000 to 150,000,
6. The golf club head manufacturing method according to claim 1, wherein a gel strength of 200 to 480 g / cm ² at an agar concentration of 4% is used. 7. A first member manufactured by the method of manufacturing a golf club head according to claim 1, wherein the first member is made of a material having a high specific gravity selected from metals, ceramics, and mixtures thereof. A golf club head comprising: a second member made of a material selected from metals, ceramics, and mixtures thereof having a lower specific gravity than the material forming the first member. 8. A wrapping member having the first member and an opening for inserting the first member, wherein the first member is inserted into the opening of the wrapping member, and the opening is the first member. 8. The golf club head according to claim 7, wherein the golf club head is closed with a material selected from metals, ceramics, and mixtures thereof having a lower specific gravity than the high specific gravity material used for the member. 9. The golf club head according to claim 8, having a streamline along a flow direction of the molding composition by injection for closing an opening of the enclosing member.