JPH0698953A - Golf club and its production - Google Patents

Abstract

PURPOSE:To improve strength, to facilitate process and to improve productivity by consisting the golf club of fiber reinforced thermoplastics, forming a shaft to a trumpet shape flaring outward at one end of the shaft and fixing the flared part to the inside wall of the hosel part of a head. CONSTITUTION:A cylindrical shaft perform 12 having the flared part 9 at one end is formed by using a fiber reinforced thermoplastic prepreg. Head parts 14 consisting of a face 4, a sole 5 and a crown 6 are formed by using the fiber reinforced thermoplastic prepreg. The shaft perform 12 and the head parts 14 are then inserted into hollow dies and the flared part 9 is disposed within the hosed part of the head parts 14. The shaft perform and the head parts are thereafter formed under heating while a pressure is applied outward from the inside of the shaft perform and the head parts 14. As a result, the strength and productivity of the golf club are improved.

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 a method for manufacturing the same, and preferably uses a fiber reinforced thermoplastic (FRTP) prepreg to form a hollow shaft preform having one end expanded and a schematic shape of a head. Form a hollow head part obtained by dividing the shaft into two or more parts, and insert these into a molding die to heat-mold while applying an internal pressure to expand one end of the shaft. Is to fix a golf club to the inner wall of the hosel part of the head to obtain a golf club having excellent strength and to improve the productivity in the production.

[0002]

2. Description of the Related Art In recent years, a golf club having a head and a shaft both made of carbon fiber reinforced plastic is known. As a manufacturing method of such a golf club, as shown in FIG. 12, a head portion 23 and a shaft portion 24, which are separately manufactured using carbon fiber reinforced plastic (CFRP), are bonded and integrated by an adhesive, A core body having a schematic shape and a core metal of a shaft portion are fitted, and a roving impregnated with a thermosetting resin is wound around the core body by a filament winding method, and the core bar is heat-cured and then the core metal is pulled out and molded. (Japanese Patent Laid-Open No. 2-128775) and the like have been proposed.

[0003]

However, in the above-mentioned manufacturing method, the shaft of the golf club is tapered, and the head portion 23 and the shaft portion 24 are bonded to each other in the middle of the shaft. The change in diameter of each bonded portion of the shaft portion 24 must be completely the same. Further, since this joint portion is formed by adhering high-rigidity materials together, the strength of the adhering portion will be insufficient unless they are adhered with high accuracy. Further, when a large stress is applied to such an adhesive portion, breakage easily occurs. In the above manufacturing method, since there is no adhesive portion, there is no power transmission loss, and it is also excellent in strength, but since this uses a thermosetting resin,
In the case of molding, a shape retainer such as a core is required,
There are problems in terms of workability and cost due to complicated steps such as a core forming step and a thermosetting step accompanied by a filament winding step.

The present invention has been made in view of the above circumstances, and is a golf club having excellent strength and a manufacturing method for manufacturing the golf club. The steps are simple, the productivity is good, and the cost is excellent. It is intended to provide a method for manufacturing a golf club.

[0005]

SUMMARY OF THE INVENTION The present invention preferably uses a fiber reinforced thermoplastic (FRTP) to form a cylindrical shaft preform whose one end is expanded outward and a schematic shape of a head. Form a hollow head part obtained by dividing it into two or more parts, and then insert the shaft preform and the head part into a hollow molding die, and at the same time, expand the diameter of the shaft preform to the head. It is placed in the hosel part of the part, and by heat-molding while applying pressure from the inside to the outside of the shaft preform and head parts, one end of the shaft is formed into a trumpet shape that expands outward. The golf club in which the expanded diameter portion is fixed to the inner wall of the hosel portion of the head is manufactured to solve the above problems.

The present invention will be described in detail below. FIG. 1 is an example of the golf club of the present invention, and FIG. 2 is a sectional view thereof. In the figure, reference numeral 1 is a shaft, 2 is a head, 3 is a hosel portion, 4 is a face surface, 5 is a sole, 6 is a crown,
Reference numeral 7 is a reinforcing member, 8 is a grip, and 9 is an enlarged diameter portion of the shaft 1.

The reason why the FRTP is used in the present invention is that the preformed article formed by heating can be reshaped by reheating. For example, in the case where a preformed body divided into two parts is re-formed and integrated, the reinforcing fiber is fluidized in the thermoplastic resin forming the pre-formed body by reheating the pre-formed body, and the reinforced fiber is formed at the joint portion. Since they are homogenized and rearranged, there is an advantage that they can be joined and integrated with excellent strength without using an adhesive, are easy to handle, and can be easily applied to machining.

The FRTP used in the present invention comprises a reinforcing fiber and a thermoplastic resin. Examples of the thermoplastic resin include polyamide, polybutylene terephthalate, polyoxymethylene (acetal resin) polycarbonate, modified polyphenylene sulfide and the like. Engineering plastic, especially its heat distortion temperature (ASTM
It is preferable that the D648, 18.6 kg / cm ² ) is 140 ° C or less. These may be used alone or as a blended polymer of two or more kinds.

As the reinforcing fiber used in the present invention, carbon fiber, aramid fiber, glass fiber and the like are used, and these may be used alone or in combination of two or more kinds. As the form of the reinforcing fiber, roving in which a large number of filaments are arranged in one direction is mainly used, but roving cloth or the like can be used in addition to this.

F composed of this reinforcing fiber and a thermoplastic resin
The RTP prepreg may be in the form of a sheet, a tape, or the like. When wound around a core metal, a tape is preferable, and when it is formed by deep drawing, a sheet is preferable. The prepreg is manufactured by, for example, a method in which a powdery thermoplastic resin is sprinkled on a reinforcing fiber and then heated and melted to impregnate it, a method in which the thermoplastic resin is made into a filament, and the filament is roving together with the reinforcing fiber, or a film The thermoplastic resin and the reinforcing fibers in a cross shape are alternately laminated and pressurized and heated. The volume of reinforcing fiber in the prepreg is 40% by volume.
It is preferably about 80%.

A shaft preform is formed using such a prepreg. First, as shown in FIG. 3, a sheet-shaped prepreg 10 is heated and softened and wound around a cored bar 11. The cored bar 11 is a tapered rod-shaped body made of metal or the like. The winding direction of the prepreg 10 is prepreg 1
The angle between the arranging direction of the reinforcing fibers in 0 and the axial direction of the cored bar 11 is 0 to 90 degrees, that is, the fiber direction is appropriately determined in the range from parallel to the axial direction of the cored bar 11 to orthogonal. To be The number of layers of the prepreg 10 is a plurality of layers so as to have a desired thickness, and the fiber direction can be changed within the above range for each winding layer. Also, the prepreg 10
As a method of winding, the tape-shaped prepreg is wound in a spiral shape by changing the angle for each winding layer.

Then, a heat-resistant non-adhesive tape such as a polyimide tape is wound around the prepreg 10 on the core metal 11 while applying tension and tightened, and then the tape is housed in a heating furnace or the like and heated to a temperature not lower than the melting temperature of the thermoplastic resin. The prepreg 10 is heated and melted, and the respective layers of the prepreg 10 are melt-bonded and integrated. After cooling, the heat-resistant non-adhesive tape is taken out, and the cored bar 11 is taken out to obtain a tapered hollow cylindrical body.

Further, as shown in FIG. 4, the tip end portion on the small diameter side of this hollow cylindrical body is expanded to form a trumpet-shaped expanded portion 9 to obtain a shaft preform 12. The diameter expansion of this tip can be performed by inserting a heated diameter expansion jig 13 into the tip of the hollow cylindrical body and deforming it by heating. Further, it is preferable that the enlarged diameter portion 9 is slightly smaller than the hosel portion 3 of the head 2 and that the diameter change thereof is similar to the diameter change of the hosel portion 3.

On the other hand, a head part is formed. 5 to 7 show examples of the shape of the head part 14,
The head part 14 shown in FIG.
It is obtained by dividing and has a face surface 4, a sole 5 and a crown 6, respectively. 6A and 6B are obtained by dividing the schematic shape of the head 2 into two parts, one having a face surface 4 and a sole 5, and one having a crown 6. What is shown in FIG. 7 is obtained by dividing the schematic shape of the head 2 into two, and has a shape having a face surface 4, a part of the sole 5 and a part of the crown 6, and a part of the sole 5. It has a shape having a part of the crown 6.

First, a sheet-shaped prepreg 15 having a desired thickness is prepared. The prepreg 15 can be formed by alternately stacking a plurality of film-shaped thermoplastic resins and sheet-shaped reinforcing fibers so as to have a desired thickness and pressurizing and heating.

Next, as shown in FIG. 8, the prepreg 15 is used to mold the head part 14 by deep drawing. The shape of the head part 14 molded here is a hollow shape obtained by dividing the schematic shape of the head 2 into preferably two or more parts, and is a shape that does not have an inverse tapered shape and can be molded by deep drawing. The face surface 4 serving as a ball striking surface has a folded-back portion 4a of at least 5 mm or more around the face surface 4 for strength against a hit ball and for facilitating molding by deep drawing. A shape or a shape in which the face surface 4 and the sole 5 are continuous is preferable. Further, as shown in FIG. 9 as an example of the overlapping portion L, an overlapping portion L is formed at the joint portion between the head parts 14 and the size of the overlapping portion L is the overlapping portion in the direction perpendicular to the joint surface. The width W of the head part 14 is equal to or larger than the thickness of the head part 14. Further, a through hole for pressurizing the inside of the head 2 is provided at an arbitrary position of the head part 14. This through hole can be provided in the sole 5, for example. The outer size of the head part 14 molded here is smaller than the desired outer size of the golf club head 2, and the difference is preferably about 0.5 mm. Next, as shown in FIG. 10, the end portion of the prepreg 15 molded by deep drawing is cut off to obtain the head 2 part 14.

The shaft preform 12 and the head 2 part 14 thus obtained are mounted in a mold 16 as shown in FIG.

The molding die 16 is a hollow body having the shape of a golf club on the inner surface, and a through hole 17 is provided at an arbitrary position on the inner wall forming the head portion, and a pressurizing medium is introduced into the head portion through the through hole 17. Then, the inside of the head can be pressurized. The through hole 17 can be provided at the position of the sole 5, for example. The tip of the molding die 16 forming the shaft portion is opened, and a pressurizing medium can be introduced into the shaft portion from this opening portion 18 to pressurize the inside of the shaft portion. Further, the entire molding die 16 is housed in a vacuum heating device (not shown).

A shaft preform 12 and a head part 14 are mounted in the molding die 16 as shown in FIG. At this time, the expanded diameter portion 9 of the shaft preform 12
Is placed in the hosel part 3 of the head part 14, and a cover tube 19 made of silicone resin or the like is inserted inside the shaft preform 12, and one end of the cover tube 19 is provided with the opening 18 of the molding die 16. It is inserted and connected to a pressure device (not shown), and the other end is sealed by a sealing member 20 such as silicone rubber. Further, a cover balloon 21 made of a silicone resin or the like is inserted inside the head part 14, and the mouth portion 2 of the cover balloon 21 is inserted.
2 is a through hole 17 of the head part 14 and the molding die 16.
And is connected to a pressure device (not shown). The thickness of the cover tube 19 and the cover balloon 21 is 0.0
5 to 2 mm can be used, preferably 0.2
The thing of ~ 1 mm is used.

At this time, a tape-shaped reinforcing member 7 made of the same material as the prepreg 15 used for forming the head part 14 is wound around the hosel portion 3 of the head part 14 for one or more turns. It is also possible to reinforce the part 3.

In this state, the inside of the vacuum heating device is evacuated to reduce the pressure between the preform 12 of the shaft and the gap between the head part 14 and the forming die 16. Further, a pressurized medium is introduced into the cover tube 19 and the cover balloon 21 to apply an internal pressure and heat. The pressurizing medium at this time may be a gas such as air or nitrogen gas, but may be a liquid such as oil.

By this heating, the shaft preform 1
2 and the head part 14 are brought into a molten state again and are pressurized from the inside to the outside by exhaust and pressurization, so that the radial dimension is expanded and the shape of the inner surface of the molding die is formed. Shaft 1 is shaped in a curved shape
The expanded diameter portion 9 is fixedly integrated with the inner wall of the hosel portion 3 of the head 2. At this time, at the same time, the reinforcing fibers in the shaft preform 12 and the head part 14 are also subjected to a radially outward force, and likewise tend to spread and become in a tension state without looseness. If the mold 16 is cooled while maintaining this pressurized state, the reinforcing fibers will be fixed in the thermoplastic resin of the matrix in a tense state.

This pressurizing and heating condition is a temperature of 250 to 28.
The temperature is 0 ° C., the pressure is 8 to 15 kg / cm ² , and the time is about 10 to 30 minutes, but it is not limited to this range, and it depends on the type of thermoplastic resin to be used, the size of the shaft 1, the amount of reinforcing fibers, etc. Can be changed as appropriate. The degree of pressure reduction in the gap between the shaft preform 12 and the head part 14 and the forming die 16 may be about 0.01 to 1 mmHg. Further, after the pressure is reduced, a preliminary pressure of about 1 to 3 kg / cm ² is applied to raise the temperature, and then the internal pressure is increased to perform pressure molding.

After the molding die 16 is cooled to about 50 to 80 ° C., the pressurized state is released and the cover tube 1 is released.
By removing 9 and the cover balloon 21 and removing the mold 16, a golf club-shaped molded body is obtained. A golf club is made by attaching grips 8, a sole plate and the like to the molded body through usual polishing and painting steps.

In the above manufacturing process, the shaft preform 15
The cover tube 19 and the cover balloon 21 are used to apply the internal pressure to the head part 14, and the reason is that when the cover tube 19 and the cover balloon 21 are integrated, they are used as the shaft end portion. This is because the cover balloon 21 cannot pass through the small-diameter portion of the shaft 1 and cannot be pulled out when trying to pull it out. Therefore, if the cover tube 19 and the cover balloon 21 can be pulled out from the end of the shaft 1, it is not necessary to use them as two separate parts. In this case, the head part 14 and the head part of the molding die 16 are penetrated. It is not necessary to form the hole 17.

[0026]

Example First, a shaft preform 12 was formed. As the core metal 11, a steel bar having an outer diameter of the large diameter portion of 11.9 mm, an outer diameter of the small diameter portion of 3.9 mm and a length of 1460 mm was prepared.

Further, a sheet-shaped prepreg 10 was prepared. Carbon fiber roving was impregnated with polycarbonate to prepare a prepreg sheet 10 for the first layer. The prepreg sheet 10 has a trapezoidal shape having an upper bottom of 44.3 mm, a lower bottom of 114 mm, and a height of 1193 mm, and has a fiber amount of 14.
1 g (50% by volume), the fiber direction of this layer and the core metal 11
The angle with respect to the axial direction of was set to +45 degrees. Similarly, a prepreg sheet 10 for the second layer was prepared, and the angle between the fiber direction of this layer and the axial direction of the core metal was −45 degrees. Also, the third
The prepreg sheet 10 for layers has a trapezoidal shape with an upper bottom of 85 mm, a lower bottom of 198 mm, and a height of 1163 mm, and the fiber amount is 24.
The weight was 7 g (50% by volume), and the angle between the fiber direction of this layer and the axial direction of the cored bar was 0 degree.

The core metal 11 was heated to 300.degree. Then
The prepreg sheet 10 is arranged on a surface plate heated to about 180 to 200 ° C., and on the prepreg sheet 10,
The core metal 11 was rolled, and the prepreg sheet 10 for the first layer, the second layer, and the third layer was sequentially wound around the core metal 11.

From above, a polyimide tape is further wound under tension, heated under pressure to melt and integrate the prepreg sheet 10 forming each layer, and after cooling, the polyimide tape and core metal 11 are removed. A hollow cylinder was obtained. Further, a heated diameter-expanding jig 13 was inserted into the tip of this hollow cylindrical body to form the diameter-expanded portion 9, and a shaft preform 12 was obtained. The outer diameter of the expanded diameter portion 9 is slightly smaller than the inner diameter of the hosel portion 3, and the difference is 0.3 mm.

On the other hand, the head part 14 was formed. First, a sheet-shaped prepreg 15 was prepared. 7 pieces of polycarbonate film and carbon fiber cloth (CF
Cross 8HS, 396g / m ² ) 7 sheets are alternately stacked, 2
Heated to 00 ° C. While maintaining this temperature, pressure was applied intermittently to homogenize the resin and remove bubbles. This pressurizing operation was performed 8 times at a pressure of 30 kg / cm ² , and the operating time was 16 minutes. Then, the prepreg sheet 1 is further heated to 250 ° C. and, while maintaining this temperature, continuously pressurized at a pressure of 15 kg / cm ² for 20 minutes.
5 was formed.

Using the prepreg sheet 15 thus obtained,
The head part 14 was molded by deep drawing. The shape of the head part 14 is a shape obtained by dividing the schematic shape of the head 2 into three parts, each having a face surface 4, a sole 5, and a crown 6. At this time, the shape of the head part 14 having the face surface 4 is such that a 5 mm folded portion 4a is formed around the head part 14.
And a head part 14 having a sole 5
A through hole was provided in the. The outer size of the head part 14 is smaller than the outer size of the golf club head 2, that is, the inner size of the mold 16 used in the final molding, and the difference is 0.5 mm. First, the prepreg sheet 15 is placed in a mold having the shape of the head part 14, and 180
After left at 6 ° C. for 6 minutes to soften the prepreg sheet 15, pressing was performed for 2 minutes while maintaining this temperature. The end part of the obtained molded product was cut off and the shape was adjusted to obtain a head part 14.

The shaft preform 12 and the head part 14 thus obtained were mounted on the forming die 16. At this time, the expanded diameter portion of the shaft preform 12 is arranged in the hosel portion 3 of the head part 14, and a 0.5 mm-thick silicone tube 19 is inserted into the shaft preform 12 and one end thereof is opened. The part 18 was inserted and connected to a pressure device, and the other end was sealed with silicone rubber 20. In addition, a silicone balloon 21 having a thickness of 0.5 mm is inserted into the head part 14 and the mouth 22 thereof has a through hole 1
7 was inserted and connected to a pressurizing device.

The mold 16 was placed in a vacuum heating device, and the inside of the vacuum heating device was depressurized to -700 mmHg. Then, nitrogen gas is introduced into the silicone tube 19 and the silicone balloon 21 to apply a preliminary pressure, and the internal pressure of the shaft preform 12 and the head part 14 is reduced to 3%.
It was set to kg / cm ² . The temperature inside the vacuum heating device was raised to 270 ° C. Further, nitrogen gas was introduced into the silicone tube 19 and the silicone balloon 21 to adjust the internal pressure to 10 kg / cm ² , and this state was left for 20 minutes.
After that, the vacuum state was broken, the mold 16 was taken out of the vacuum heating device, and it was cooled. Mold mold 16 temperature is about 80
When the temperature reached ℃, the pressurizing state was released, the mold 16 was released from the mold, and the silicone tube 19 and the silicone balloon 21 were removed to obtain a golf club-shaped molded body.

The molded body thus obtained was subjected to usual polishing and painting steps, and then a grip 8, a sole plate and the like were attached to obtain a golf club.

[0035]

As described above, the golf club of the present invention is made of fiber reinforced thermoplastic, one end of the shaft is formed in the shape of a trumpet that expands outward, and the expanded portion of the head is formed. It is fixed to the inner wall of the hosel part. Therefore, structurally, the shaft does not come off from the head, and the shaft is integrated without using an adhesive, so that it has excellent strength.

Further, the golf club manufacturing method of the present invention uses a fiber reinforced thermoplastic, and a cylindrical shaft preform whose one end is expanded outwardly,
A hollow head part obtained by dividing the schematic shape of the head into preferably two or more parts is formed, and then the shaft preform and the head part are inserted into a hollow mold and the shaft preform is formed. The diametrically expanded portion is placed in the hosel part of the head part, and the shaft preform and the head part are heated and formed while applying pressure from the inside to the outside. Therefore, since FRTP is used, by reheating the preform, the reinforcing fibers are in a fluidized state in the thermoplastic resin forming the preform, and the reinforcing fibers are homogenized and rearranged at the joint portion, so that the bonding is performed. It can be joined and integrated with excellent strength without using an agent, is easy to handle, and can be easily applied to machining. Further, the reinforcing fibers existing in the thermoplastic resin as the matrix can be molded in a tension state without looseness, and an excellent reinforcing effect by the reinforcing fibers can be obtained. Furthermore, since head parts can be formed by using FRTP and these can be joined and integrated, it is possible to form a core, wrap roving around it by the filament winding method, or perform sheet patchwork. Without, it is possible to easily form a head having a desired shape.

Further, the golf club can be manufactured by inserting the separately molded shaft preform and the head part into the molding die and integrating them by the pressure heating process, so that the process is simple, Since it can be easily made into a line and productivity can be improved, the cost is also excellent.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a golf club of the present invention.

2 is a cross-sectional view of the golf club shown in FIG.

FIG. 3 is an explanatory diagram of a step of winding a prepreg around a mandrel in an example of the manufacturing method of the present invention.

FIG. 4 is an explanatory diagram of a process of forming a diameter-enlarged portion in an example of the manufacturing method of the present invention.

FIG. 5 is a perspective view showing an example of the shape of the head part of the manufacturing method of the present invention.

FIG. 6 is a perspective view showing an example of the shape of the head part of the manufacturing method of the present invention.

FIG. 7 is a perspective view showing an example of the shape of the head part of the manufacturing method of the present invention.

FIG. 8 is an explanatory diagram of a deep drawing step of forming a head part in an example of the manufacturing method of the present invention.

FIG. 9 is an explanatory diagram of an overlapping portion of head parts in an example of the manufacturing method of the present invention.

FIG. 10 is an explanatory diagram of a trimming process for forming a head part by an example of the manufacturing method of the present invention.

FIG. 11 is an explanatory view showing a state in which a shaft preform and a head part are inserted into a molding die in an example of the manufacturing method of the present invention.

FIG. 12 is a cross-sectional view showing an example of a conventional golf club.

[Explanation of symbols]

1 ... Shaft, 2 ... Head, 3 ... Hosel part, 9 ... Expanded part, 10 ... Prepreg (shaft), 12 ... Shaft preform, 14 ... Head parts, 15 ... Prepreg (head), 16 ... Mold

Claims (2)

[Claims] 1. A fiber reinforced thermoplastic material, wherein one end of the shaft is formed into a trumpet shape that expands outward, and the expanded part is fixed to the inner wall of the hosel part of the head. A golf club to do. 2. A fiber-reinforced thermoplastic prepreg is used to form a cylindrical shaft preform whose one end expands outward and a hollow head part having a general shape of the head. Insert these shaft preforms and head parts into the hollow mold, and arrange the expanded part of the shaft preforms inside the hosel part of the head parts so that the shaft preforms and head parts are A method for manufacturing a golf club, which comprises heat-molding while applying a pressure to one side.