JPH0511887Y2 - - Google Patents

Description

[Detailed explanation of the idea]

[Technical Field] The present invention relates to an FRP reinforced golf club shaft. [Prior Art] Various golf club shafts are known that have a surrounding resin layer (FRP layer) reinforced with carbon fibers wound around a shaft core material using a filament winding method. In this case, carbon fiber is very expensive, so it can be produced as cheaply as possible,
Furthermore, a structure with excellent strength is also desired. According to Japanese Patent Publication No. 52-26794, the reinforcing fibers have a winding angle (orientation angle) of 45° or less at the narrowest diameter part, and the winding angle decreases continuously toward the thicker diameter part. A golf club shaft reinforced with an FRP layer is shown. Although this golf club shaft is satisfactory in terms of mechanical strength, it has the disadvantage of being expensive in actual manufacture. In other words, in the case of this golf club shaft, the winding angle decreases toward the larger diameter portion, but in the case of filament winding molding, the FRP layer thickness tends to increase as the winding angle increases. Therefore, the grip side
The thickness of the FRP layer becomes smaller, and the tip side (tip side)
There is a problem that the thickness of FRP becomes too large. Therefore, in the case of this golf shaft, in order to adjust the thickness of the FRP layer along the shaft axis direction so that the tip side has an appropriate bend in the final finishing process, the thickness of the FRP layer on the tip side must be adjusted by a certain amount. It becomes necessary to partially cut and remove it. As a result, the number of cut portions of the fiber increases, resulting in a large amount of wasted fiber, and the disadvantages remain that the strength on the chip side is reduced. [Objective] The present invention aims to overcome the above-mentioned drawbacks found in the prior art. [Structure] According to the present invention, the golf club shaft includes an inner resin layer and an outer resin layer reinforced with wound fibers, and the inner resin layer has a fiber winding angle of 25 to 40 degrees at its widest diameter part. and the fiber winding angle of the outer resin layer is
The fiber winding angle of the inner resin layer at its narrowest diameter is in the range of 20 to 40 degrees, the fiber winding angle of the inner resin layer is in the range of 10 to 20 degrees, and the fiber winding angle of the outer resin layer is in the range of 5 to 15 degrees, and each inner resin layer and a golf club shaft characterized in that the fiber winding angle of the outer resin layer continuously decreases from the widest diameter portion to the thinnest diameter portion. Next, the golf club shaft of the present invention will be explained with reference to the drawings. FIG. 1 is an explanatory cross-sectional view of the golf club shaft of the present invention. The reinforcing fibers in this FRP layer are wound using the filament winding method, and the winding angle of the fibers is an angle with respect to the shaft axis direction, and the angle becomes smaller as it goes to the narrower diameter part. The angle of the widest diameter part is 40° or less. That is, the second
As shown in the figure, the winding angle a of the fiber at the thickest diameter part is
40° or less, the angle a is larger than the winding angle b of the fibers at the thinnest diameter portion, and the orientation angle of the intermediate fibers gradually increases from the thinnest diameter portion to the thickest diameter portion. . The preferred fiber winding angle a is 20 to 40
degree, and the winding angle b is 5 to 20 degrees. Further, in the present invention, the reinforcing fiber wound layer has a two-layer structure (inner layer and outer layer) with two types of winding angle ranges. The winding angles in the inner layer and outer layer are set as shown in Table 1.

〔effect〕

The golf club shaft of the present invention is made by winding reinforcing fibers impregnated with a thermosetting resin such as epoxy resin on a core material using the filament winding method, as described above, to create a fiber layer, and then taping the entire structure. After fixation, the core material is removed, and the resulting cured product is polished to a predetermined outer diameter. In the present invention, as mentioned above, the winding angle of the wound fiber layer becomes smaller as it goes toward the narrowest diameter part of the shaft. Since the thickness of the FRP layer increases as it goes toward the smaller diameter portion, the thickness of the FRP layer obtained by heating and curing will not become too large than necessary at the narrow diameter portion. For example, in the case of a normal golf club shaft, FRP at the widest diameter part
The thickness of the layer is approximately 1.2 mm, and the thickness of the FRP layer at the narrowest diameter portion is approximately 2.5 mm. Therefore, such FRP
When polishing a shaft with layers to smoothly adjust the FRP layer thickness to approximately 1.0 mm at the widest diameter and approximately 2.0 mm at the narrowest diameter, it is necessary to , it is only necessary to remove about 0.5 mm, which makes it possible to relatively avoid cutting the reinforcing fibers and obtain a shaft with excellent strength. On the other hand, contrary to the present invention, the winding angle of the fiber becomes smaller as it goes toward the thickest diameter part, and the FRP layer thickness at the thickest diameter part is reduced to approximately
When set to 1.2mm, the FRP layer thickness at the smallest diameter part will be approximately 3.0mm, and by polishing, the thickness of the FRP layer at the smallest diameter part will be approximately 3.0mm.
In order to adjust the FRP layer thickness to about 2.0 mm, which is the same as above, it is necessary to remove about 1.0 mm at the narrowest diameter part.
In this case, a considerable portion of the reinforcing fibers must be cut. Next, the weight of the golf club shaft of the present invention before polishing will be shown in comparison with that of a conventional product. The outer diameter of the thinnest part (tip side diameter) of the core metal used was 3.8 mm, and the outer diameter of the thickest part (grip side diameter):
It is a straight tapered tube with dimensions of 14.0 mm.

[Table] As described above, the golf shaft of the present invention:
The weight before polishing is reduced, and therefore the amount of polishing is reduced during polishing, and the amount of fibers removed by polishing is also necessarily reduced. In addition, since the winding angles of the inner and outer layers are defined as described above, the large diameter side (grip side) of the golf club shaft has appropriate bending rigidity, and the small diameter side (tip side) has sufficient torsional rigidity. This is the bending stiffness and bending strength. Therefore, the golf club shaft of the present invention is not only economically superior but also superior in strength.

[Brief explanation of the drawing]

FIG. 1 is an explanatory cross-sectional view of the golf club shaft of the present invention, and FIG. 2 is an explanatory view showing the fiber winding angle when fibers are wound around the shaft core material.

Claims (1)

[Scope of utility model registration request] A golf club shaft comprising an inner resin layer and an outer resin layer reinforced with wound fibers, wherein the inner resin layer has a fiber winding angle of 25 to 40 degrees and the outer resin layer has a fiber winding angle of 25 to 40 degrees at its widest diameter part. The fiber winding angle of the inner resin layer is 10 to 20 degrees and the fiber winding angle of the outer resin layer is 5 degrees.
~15 degrees, and is characterized in that the fiber winding angle of each inner resin layer and outer resin layer continuously decreases from the thickest diameter part to the thinnest diameter part. golf club shaft.