JPH0966128A - Manufacture of hollow shaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing efficiently a hollow shaft which is suitable for a manufacture of a golf shaft having an S-like curve, and which is inexpensive and excellent in the quality. SOLUTION: In a method of manufacturing a hollow shaft having a curved part at its front end, comprises the steps of joining a straight pipe member 14 to be formed into the curved part, to an end part 11a of a first straight core member 11, inserting a second core member 12 in a pipe member 14, winding a prepreg sheet onto the first core member 11 and the pipe member 14, lapping thus wound prepreg sheet, removing the second core member 12, compressing and baking the prepreg sheet fused to the first core member 11 and the pipe member 14 within molding dies, curing the pipe member 14 in a predetermined shape, and removing the first core member 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a hollow shaft having a curved portion at its tip, and more particularly to a golf shaft having an S-shaped curved portion at its tip.

[0002]

2. Description of the Related Art For example, in the golf club shown in FIG. 13, a gentle S-shaped curved portion 1a is formed at the tip of a shaft 1.
And the putter head 2 is fixed to the end of the curved portion 1a. Conventionally, this type of golf shaft has been manufactured by, for example, a so-called internal pressure manufacturing method. In this internal pressure manufacturing method,
A prepreg sheet is wound around a core material (core metal), and the wound prepreg sheet is molded while being supported by the core material. After molding, the core material used is decoreed from the golf shaft as a product.

In the conventional internal pressure manufacturing method,
A silicon tube into which high-pressure compressed air is injected has been used as a core material for a prepreg sheet to form the curved portion 1a of the shaft 1. By pressurizing the silicon tube from the inside, the strength as the core material can be secured and the silicon tube can be deformed along the S-shape of the molding die during molding. That is, an S-shaped curved shape is obtained by molding by using a partially flexible silicon tube core material for the curved portion 1a.

[0004]

However, in the conventional method for manufacturing a golf shaft by the internal pressure manufacturing method, the silicon tube used as a part of the core material is fatigued if it is used at most a few times, so that it is disposable. It was. Thus, the disposable use of the silicone tube is extremely uneconomical. Moreover, in addition to the molding die, equipment for sending high-pressure compressed air to the silicon tube is required, so that the cost of the equipment is large.

In view of the above situation, the present invention is particularly suitable for manufacturing a golf shaft having an S-shaped curved portion, and provides a method for manufacturing a hollow shaft which is low in cost and can efficiently obtain a product of excellent quality. The purpose is to do.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies on such problems, and as a result,
Instead of the silicon tube used in the conventional manufacturing method,
By using a carbon or metal pipe material corresponding to the S-shaped curved portion, it was found that this pipe material acts as a core material, and the present invention has been completed based on this finding.

That is, the present invention is (1) a method of manufacturing a hollow shaft having a curved portion, wherein a linear pipe material for forming the curved portion is joined to an end portion of a linear core material. A step of winding a prepreg sheet around the core material and the pipe material, wrapping the wrapped prepreg sheet, and pressing and bending the prepreg sheet adhered to the core material and the pipe material in a molding die. And a step of decoreing the core material, and a method of manufacturing a hollow shaft.

(2) A method of manufacturing a hollow shaft having a curved portion, wherein a linear pipe material for forming the curved portion is joined to an end portion of the linear first core member. At the same time, a step of inserting a second core material into the pipe material, a step of winding a prepreg sheet around the first core material and the pipe material, and wrapping the wound prepreg sheet; Decoreing the material,
A step of pressing and bending the prepreg sheet adhered to the first core material and the pipe material in a molding die, and firing.
And a step of decoreing the first core material.

(3) In the pipe material, a prepreg sheet made of a carbon fiber material is wound around a linear third core material such that the fiber direction of the prepreg sheet is inclined with respect to the third core material. The method for producing a hollow shaft according to the above (2) is formed by decoreing the third core material from a prepreg sheet formed into a pipe shape by the winding.

Further, (4) is a method of manufacturing a hollow shaft having a curved portion, wherein the end of the linear core member is
A step of joining a linear metal pipe material to form the curved portion, a step of winding a prepreg sheet around the core material and the pipe material, and wrapping the wound prepreg sheet, the core material and the pipe A method for manufacturing a hollow shaft comprises a step of pressurizing and bending the prepreg sheet adhered to a material in a molding die, and a step of decoreing the core material.

Further, (5), the hollow shaft resides in the method for producing a hollow shaft according to any one of the above (1) to (4), which is a golf shaft having an S-shaped curved portion at its tip.

[0012]

The present invention is preferably applied to the manufacture of a golf shaft having an S-shaped curved portion at its tip. As a basic step of this manufacturing method, a prepreg sheet is wound around a core material, and this is molded. A linear carbon or metal pipe material for forming a curved portion is joined to the end of the linear core material, and a predetermined prepreg sheet is wound around these. The pipe material is thinly formed of carbon or a metal material and has a certain rigidity and an appropriate flexibility, and therefore acts as a core material around which the prepreg sheet is wound. The pipe material itself also serves as a constituent member of the finally formed golf shaft, so that the strength of the golf shaft can be improved.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of a method for manufacturing a hollow shaft according to the present invention will be described below with reference to FIGS. In this embodiment, the present invention is applied to the manufacture of a hollow shaft having a curved portion, for example, a golf shaft 1 having an S-shaped curved portion 1a at the tip shown in FIG.

In the method of the present invention, as shown in FIG. 1, a linear first core member 11 substantially corresponding to the straight portion of the golf shaft 1 and a second core member 12 substantially corresponding to the curved portion 1a. To use. End 11a of the first core material 11
A linear pipe material 14 (see FIG. 4) for forming the curved portion 1a is joined to the first core material 13. The third core material 13 is used to form the pipe material 14. These core materials 11,
12 and 13 are made of iron.

The outer diameter of the end 11a of the core 11 and the outer diameter of the second core 12 are the same, and the outer diameter of the third core 13 is slightly larger (about 0.1 mm). ) Is set. Thereby, as will be described later, it is possible to facilitate insertion of the end portion 11a of the first core material 11 and the second core material 12 into the pipe material 14. Here, first, the pipe material 14
The prepreg sheet 14a for forming the is wound around the third core 13 as shown in FIG. The prepreg sheet 14a is preferably a thin sheet made of carbon fiber impregnated with resin.

The prepreg sheet 14a is attached to the third core 13
It is preferable to incline the direction of the carbon fiber with respect to the axial direction of the third core material 13 when winding it on the. Such an angle allows proper bending after firing. The prepreg sheet 14a wound around the third core 13 is then wrapped with a wrapping tape. Then, the wrapped material is fired at a predetermined temperature, and then the third core 13
Is decoreed.

Further, the pipe material 14 is obtained by peeling off the wrapping tape and cutting it to a predetermined length. The length of the pipe material 14 is cut so as to be slightly shorter than that of the second core material 12. Pipe material 1 thus obtained
4 is fitted into the end portion 11a of the core material 11, and the pipe material 14
The second core material 12 is inserted therein. By thus joining the first core material 11, the second core material 12, and the pipe material 14 to each other, the linear core body 10 as shown in FIG. 4 is configured.

Next, as shown in FIG. 5, a prepreg sheet for forming the entire golf shaft 1 is wound around a predetermined region of the core body 10 around the first core material 11 and the pipe material 14. In this case, the carbon fiber prepreg sheet 15a forming the bias layer 15 of the golf shaft 1 and the carbon fiber prepreg sheet 16a forming the straight layer 16 are sequentially wound. In the bias layer 15 and the straight layer 16, the directions of the carbon fibers intersect each other or coincide with the axial direction of the core 10.

The bias layer 15 and the straight layer 16 are composed of
In addition, several plies (layers) are formed. As shown in FIG. 6, the prepreg sheets 15a and 16a wound around the core 10 are then wrapped with a wrapping tape. Then, as shown in FIG. 7, the second core material 12 is decoreed from the wrapped material. Next, the first core material 11 and the pipe material 14 to which the prepreg sheets 15a and 16a are adhered are put into a predetermined molding die.

Here, the molding die 100 used in this embodiment is composed of an upper die 101 and a lower die 102 as shown in FIG. 8, for example. Mold 100 for molding
Has a cavity 100a corresponding to the straight portion of the golf shaft 1 and the curved portion 1a. As shown in FIG. 9, the prepreg sheets 15a and 16a wound around the first core material 11 and the pipe material 14 are pressure-curved in the molding die 100 and are fired at a predetermined temperature in an electric furnace. To be done.

As described above, since the second core material 12 has already been decoreed from the pipe material 14, the rigidity of this portion is relatively small. By firing using the molding die 100, the pipe material 14 and the prepreg sheets 15a and 16a around the pipe material 14 are appropriately curved and molded, whereby the curved portion 1a of the golf shaft 1 can be formed.
After firing, the molding die 100 is released, and the core body 10 to which the prepreg sheets 15a and 16a are adhered is completely taken out of the molding die 100.

Next, the core material 11 is decoreed from the core body 10, the wrapping tape is peeled off and cut into a predetermined length, and the golf shaft 1 as a product as shown in FIG.
Is obtained. This golf shaft 1 has a bias layer 15
And the curved portion 1 having a laminated structure of the straight layer 16
In a, the carbon pipe material 14 is integrated inside. By using the pipe material 14 as a part of the golf shaft 1 as described above, it is possible to save the labor of extracting the pipe material 14 and to remarkably improve the strength of the S-shaped curved portion 1a.

11 and 12 show a second embodiment of the method for manufacturing a hollow shaft according to the present invention. Second
In the embodiment, the present invention is applied to the manufacture of the golf shaft 1 having the S-shaped curved portion 1a at the tip, and the straight core 21 and the curved portion 1a substantially corresponding to the straight portion of the golf shaft 1 are almost the same. The corresponding metal (copper or brass) pipe material 22 is used. The structure of the core member 21 is almost the same as that of the first core member 11 in the first embodiment, and the linear pipe member 22 for forming the curved portion 1a is joined to the end portion 21a thereof. (See Figure 12).

The outer diameter of the joint portion between the core material 21 and the pipe material 22 is the same, and the inner diameter of the pipe material 22 is the core material 21.
Is set to have the same diameter as the outer diameter of the end 21a. Core material 21
By joining the pipe material 22 to each other, as shown in FIG.
Such a linear core body 20 is formed. Next, the core body 2
The prepreg sheet (which is substantially the same as the above-mentioned prepreg sheets 15a and 16a) for forming the entire golf shaft 1 is wound around a predetermined area around the core material 21 and the pipe material 22 at 0.

In this case, if a large number of small holes are formed in the pipe material 22 or a large number of grooves are formed on the surface thereof,
When the prepreg sheet is wound, the prepreg sheet can be easily wound due to friction, and the adhesion between the prepreg after firing and the pipe material 22 can be improved. In addition,
Similar effects can be obtained by subjecting the pipe material 22 to appropriate knurling. The prepreg sheet wound around the core body 20 is then wrapped with a wrapping tape.

The following steps are performed in substantially the same manner as in the case of the first embodiment. That is, after lapping, it is put into a predetermined molding die (see FIG. 8), pressurized in the molding die, and baked at a predetermined temperature in an electric furnace. In this case as well, the pipe material 22 and the prepreg sheet around the pipe material 22 are appropriately curved and formed, whereby the curved portion 1a of the golf shaft 1 can be formed. In particular, in the second embodiment, the pipe material 22 is made of a thin metal, so that the rigidity of the portion is relatively small, but on the other hand, the core material sufficient for winding the prepreg sheet is used. Also has a moderate strength as. Therefore, it is not necessary to separately use a core material for the pipe material 22,
Therefore, it is possible to omit the step of decentering the second core material 12 before inserting the mold as in the first embodiment.

Although the preferred embodiment of the present invention has been described, various modifications can be made without departing from the scope of the present invention. For example, in addition to the case of a golf shaft as a hollow shaft to be manufactured by the method of the present invention, it can be effectively applied to a shaft of this type having a plurality of layered structures. It is possible to obtain the same operational effect as.

[0028]

As described above, according to the present invention, by using a pipe material made of carbon or metal which can act as a core material in shaft molding, a high quality product can be obtained in a relatively simple process. be able to. That is, for example, since the pipe material itself constitutes a part of the product, it is not necessary to pull it out on the way unlike the conventional manufacturing method, and the strength of the final product is improved. Further, since no special equipment other than the molding die is required, there is an advantage that a low cost product can be realized.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration example of a core material used in a first embodiment of the present invention.

FIG. 2 is a diagram showing a manufacturing process of the pipe material according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a manufacturing process of the pipe material according to the first embodiment of the present invention.

FIG. 4 is a diagram showing a core body according to the first embodiment of the present invention.

FIG. 5 is a diagram showing a step of winding a prepreg sheet around a core body according to the first embodiment of the present invention.

FIG. 6 is a diagram showing a state in which a prepreg sheet is wound around a core body according to the first embodiment of the present invention.

FIG. 7 is a diagram showing a state in which a second core material according to the first embodiment of the present invention is decoreed.

FIG. 8 is a diagram showing a structural example of a molding die used in the method of the present invention.

FIG. 9 is a diagram showing a molding process in the molding die according to the first embodiment of the present invention.

FIG. 10 is a view showing the shaft at the final stage of molding in the first embodiment of the present invention.

FIG. 11 is a diagram showing a configuration example of a core material used in the second embodiment of the present invention.

FIG. 12 is a diagram showing a core body according to a second embodiment of the present invention.

FIG. 13 is a schematic configuration diagram of a conventional golf shaft.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Golf shaft 1a ... Curved part 10 ... Core body 11 ... 1st core material 12 ... 2nd core material 13 ... 3rd core material 14 ... Pipe material 14a ... Pre-preg sheet 15 ... Bias layer 16 ... Straight layer 100 ... Mold 100a ... Cavity

[Procedure amendment]

[Submission date] October 6, 1995

[Procedure amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0025

[Correction method] Change

[Correction contents]

In this case, if a large number of small holes are formed in the pipe material 22 or a large number of grooves are formed on the surface thereof,
Guests can be easily wound by friction in winding the prepreg sheet, prepreg sea after firing
It is possible to improve the adhesion between the bets and the pipe member 22.
The same effect can be obtained by subjecting the pipe material 22 to appropriate knurling. The prepreg sheet wound around the core body 20 is then wrapped with a wrapping tape.

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Claims (5)

[Claims] 1. A method of manufacturing a hollow shaft having a curved portion, comprising: joining a linear pipe material for forming the curved portion to an end portion of the linear core material; Winding a prepreg sheet around the pipe material, wrapping the wrapped prepreg sheet, and bending the prepreg sheet adhered to the core material and the pipe material by pressurizing and bending in a molding die, And a step of decoreing the core material. 2. A method of manufacturing a hollow shaft having a curved portion, wherein a straight pipe material for forming the curved portion is joined to an end portion of a straight first core material, and the pipe is formed. Inserting a second core material into the material, winding a prepreg sheet around the first core material and the pipe material, and wrapping the wound prepreg sheet, and decoreing the second core material And a step of firing the prepreg sheet adhered to the first core material and the pipe material by pressurizing and bending the prepreg sheet in a molding die, and a step of decoreing the first core material. A method for manufacturing a hollow shaft, comprising: 3. The pipe material is formed by winding a prepreg sheet made of a carbon fiber material around a linear third core material such that the fiber direction of the prepreg sheet is inclined with respect to the third core material.
The hollow shaft manufacturing method according to claim 2, wherein the hollow core shaft is formed by decoreing the third core material from a prepreg sheet formed into a pipe shape by the winding. 4. A method of manufacturing a hollow shaft having a curved portion, the method comprising: joining a linear metal pipe material for forming the curved portion to an end portion of the linear core material; A step of winding a prepreg sheet around the core material and the pipe material, and wrapping the wrapped prepreg sheet; and a step of bending the prepreg sheet adhered to the core material and the pipe material under pressure in a molding die and firing the prepreg sheet. And a step of decoreing the core material, the method of manufacturing a hollow shaft. 5. The method of manufacturing a hollow shaft according to claim 1, wherein the hollow shaft is a golf shaft having an S-shaped curved portion at a tip thereof.