JPH08141121A - Manufacture of golf shaft - Google Patents

Abstract

PURPOSE: To enhance material yields by reducing the amount of polishing during a polishing process in which an outer shape is finished, in a method for manufacturing a golf shaft using filament winding method. CONSTITUTION: A bundle of resin-impregnated long fibers is wound around a core by filament winding method to form a long-fiber reinforcement layer 2, and a half-set resin film is wound onto the long-fiber reinforcement layer 2 to form a resin layer 1, and after the resin is set and the core is drawn out, the outermost resin layer 1 or part of the resin layer 1 and the long-fiber reinforcement layer 2 are polished.

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 golf shaft made of fiber reinforced plastic.

[0002]

2. Description of the Related Art With the advent of a fiber reinforced plastic (hereinafter, abbreviated as FRP) golf shaft (hereinafter, abbreviated as a shaft) mainly using carbon fibers, the weight can be reduced as compared with a conventional metal shaft, Moreover, the degree of freedom in designing the shaft rigidity has expanded. And the FRP shaft is now
It is manufactured by a filament winding method (hereinafter abbreviated as FW method) and a sheet winding method (hereinafter abbreviated as SW method). The FW method is a method in which a long fiber bundle impregnated with a resin is wound around a cored bar, the resin is cured in a curing furnace, and then the outer shape is polished. On the other hand, in the SW method, long fibers aligned in one direction are impregnated with a resin, and a semi-cured sheet-like prepreg is wound around a core bar, and then FW
This is a method similar to the method.

[0003]

By the way, the FW method is
Compared with the SW method, the winding angle of the fiber can be arbitrarily changed in the longitudinal direction of the shaft by the computer-controlled FW winding machine, so that the degree of freedom in designing the rigidity distribution is large and the fiber orientation angle is axially symmetric. Moreover, since the wall thickness in the circumferential direction is uniform, there is little variation in the flex and bending natural frequencies. However, on the other hand, the small diameter side of the shaft,
Since the same amount of long fiber bundles are wound on both the large diameter side, the thin diameter side becomes thicker, and the unevenness of the surface is unavoidable.
It has a disadvantage that the yield of materials is poor because the amount of polishing is large in surface finishing. Carbon fibers are generally expensive, and the FW method makes it difficult to reduce the material cost of the shaft because the material yield is low.

The present invention is intended to provide a method for manufacturing a golf shaft which can improve the material yield by reducing the polishing amount even in the FW method.

[0005]

According to the present invention, a long fiber bundle impregnated with a resin is wound around a core metal by a filament winding method to form a long fiber reinforcing material layer, and a semi-cured resin is semi-cured on the long fiber reinforcing material layer. After forming a resin layer by winding the resin film in the state, after curing the resin and pulling out the core metal, a golf shaft of the outermost resin layer or the resin layer and a part of the long fiber reinforcement layer is polished. It relates to a manufacturing method. In the present invention, as the fiber forming the long fiber reinforcement material layer,
Carbon fiber, glass fiber, ceramic fiber and the like are available, but carbon fiber is usually used.

The FW method is generally a wet method in which a long fiber bundle is impregnated with an epoxy resin which is liquid at room temperature and wound around a core metal as it is. By this method, a long fiber reinforcing material layer is provided and a resin film is formed thereon. Wrap around. In this case, since the fibers are wound around the cored bar under tension, excess resin oozes out on the surface of the long fiber reinforcing material layer and stays between the fibers and the resin film. When the shafts that have been wound are piled up due to the influence, the stagnant resin may be liquid and thus the outer shape may be deformed, and if cured as it is, unevenness may remain on the surface. It is preferable to use a tow prepreg obtained by impregnating a long fiber bundle with a resin in a semi-cured state and winding it around a core metal, because the resin does not seep out and the surface is not deformed even after winding the resin film.

The resin film may be made of any material as long as it adheres well to the long fiber reinforcing material layer. However, epoxy resin is most preferable because the same material ensures adhesive strength. After forming the resin layer, completely cure the resin in a curing oven,
The core metal may be removed from the mold and polished to a predetermined size. The outer shape depends on the type of shaft and cannot be generally stated, but only the outermost resin layer or part of the long fiber reinforcement layer is polished, but the polishing amount of the long fiber reinforcement layer is reduced as much as possible. The core metal shape, the fiber winding angle, and the number of reciprocations are set as described above.

[0008]

In general, in the FW method, a large number of long fiber bundles must be wound in order to obtain the polishing amount. However, according to the method of the present invention, predetermined performance (flex, torsion, weight, etc.)
Is ensured and wound to such an extent that a predetermined outer diameter is reached, and the polishing allowance for removing irregularities on the surface is supplemented with a resin layer. This method reduces the amount of reinforcing fibers discarded in the polishing process.

[0009]

EXAMPLES Next, examples will be described, but the present invention is not limited to these examples. Example According to the FW method, a carbon fiber bundle (Toray-made Torayca T700S) was impregnated with a predetermined core metal and epoxy resin was impregnated into a semi-cured tow prepreg (resin content 30% by weight). 26 reciprocating windings to form a long fiber reinforcement layer, and then a thickness of 50 μm on the long fiber reinforcement layer.
Epoxy resin film (manufactured by Hitachi Chemical Co., Ltd., AS
-3000) was wound to have a wall thickness of 0.2 mm to form a resin layer. After that, the resin was heat-cured in a curing oven, the cored bar was pulled out, and only the resin layer was outer diameter polished to have a predetermined size. FIG. 1 shows a vertical sectional view thereof. In the figure,
Reference numeral 2 is a long fiber reinforcing material layer of carbon fiber, and 1 is a resin layer of an epoxy resin film. The number of reciprocations and the shape of the cored bar were determined so that only the resin layer 1 could be polished.

Comparative Example A carbon fiber bundle of the same type as that of the example was wound 32 reciprocations at a winding angle of 25 degrees by the wet FW method. The tension applied to the fiber was adjusted so that the resin content was the same as in the example. After that, the resin was heat-cured, the core metal was pulled out, and the outer diameter was ground to the same size as that of the example.

Table 1 shows the flexes, torsions, weights, and yields of carbon fibers used for the shafts of Examples and Comparative Examples. The flex, the torsion, and the weight were the same in both the example and the comparative example, but when the carbon fiber used was set to 100, the example could reduce by 84% and 84%.

[0012]

[Table 1]

[0013]

According to the present invention, even in the FW method, the polishing amount can be reduced to improve the yield of reinforcing fibers and reduce the material cost.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a golf shaft according to an embodiment of the present invention.

[Explanation of symbols]

 1 ... Resin layer 2 ... Long fiber reinforcement layer

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Claims (3)

[Claims] 1. A long-fiber bundle impregnated with a resin is wound around a core metal by a filament winding method to form a long-fiber reinforcing material layer, and a semi-cured resin film is wound on the long-fiber reinforcing material layer to form a resin. A method for producing a golf shaft, comprising forming a layer, curing the resin, pulling out the core metal, and then polishing the outermost resin layer or the resin layer and a part of the long fiber reinforcing material layer. 2. The production of a golf shaft according to claim 1, wherein the long fiber reinforcement material layer is obtained by winding a tow prepreg obtained by impregnating a long fiber bundle with a resin into a semi-cured state, around a core metal by a filament winding method. Method. 3. The golf shaft manufacturing method according to claim 1, wherein the resin film is an epoxy resin film.