Golf club shaft and golf club

Abstract

To provide a golf club shaft and golf club capable of meeting both requirements of reducing a shaft weight and maintaining shaft strength.SOLUTION: A golf club shaft is formed by winding and thermally curing a plurality of layers of prepreg made of reinforced fibers impregnated with thermosetting resin. The prepreg includes 0° prepreg whose fiber direction is parallel to a longitudinal direction of the shaft, 90° prepreg whose fiber direction is orthogonal to the longitudinal direction of the shaft, and a bias prepreg whose fiber direction is inclined with respect to a shaft longitudinal direction, where a mass ratio of the 90° prepreg to the bias prepreg is 1.0 or more, and a mass ratio of the 0° prepreg to the bias prepreg is 2.6 or more.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a golf club shaft and a golf club using the same. [Background technology]

[0002] 2. Description of the Related Art In place of steel golf club shafts, golf club shafts made of FRP (Fiber Reinforced Plastics) are widely used. The FRP is made by winding multiple layers of prepreg, which is made of reinforcing fibers such as carbon fibers impregnated with thermosetting resin, and then heat-curing the layers.

[0003] The prepregs used include 0° prepregs, whose fiber direction is approximately parallel to the longitudinal direction of the shaft, 90° prepregs, whose fiber direction is approximately perpendicular to the longitudinal direction of the shaft, and bias prepregs, whose fiber direction is inclined at approximately 45° to the longitudinal direction of the shaft.

[0004] Conventionally, efforts have been made to develop golf club shafts that can meet the requirements for both light weight and strength by combining prepregs with different fiber directions. However, when the weight of a golf club shaft is reduced, it becomes difficult to maintain its strength, and therefore there is a demand for a golf club shaft that can maintain the required strength while still being lighter. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 9-131422 [Patent Document 2] JP 2000-51413 A Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a golf club shaft and a golf club that can meet both requirements for reducing the weight of the shaft and maintaining the strength of the shaft. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention provides a golf club shaft formed by winding and heat-curing multiple layers of prepregs in which reinforcing fibers are impregnated with a thermosetting resin, wherein the prepregs include a 0° prepreg whose fiber direction is parallel to the longitudinal direction of the shaft, a 90° prepreg whose fiber direction is perpendicular to the longitudinal direction of the shaft, and a bias prepreg whose fiber direction is inclined with respect to the longitudinal direction of the shaft, and wherein the mass ratio of the 90° prepreg to the bias prepreg is 1.0 or more, and the mass ratio of the 0° prepreg to the bias prepreg is 2.6 or more. The present invention also provides a golf club comprising the above golf club shaft, a club head and a grip attached thereto. Effect of the Invention

[0008] According to the present invention, it is possible to provide a golf club shaft and a golf club that can meet the requirements for both reducing the weight of the shaft and maintaining the strength of the shaft. [Brief description of the drawings]

[0009] [Figure 1] 1 is an exploded perspective view showing a schematic configuration of a golf club shaft according to an embodiment of the present invention; [Diagram 2] FIG. 1 is a diagram showing a first embodiment (Example 1) of a laminated structure of prepregs for a golf club shaft according to one embodiment of the present invention. [Diagram 3] FIG. 4 is a diagram showing a second aspect (Example 2) of the laminated structure of the prepreg of the golf club shaft according to one embodiment of the present invention. [Figure 4]FIG. 4 is a diagram showing a third aspect (Example 3) of the laminated structure of the prepreg of the golf club shaft according to one embodiment of the present invention. [Diagram 5] FIG. 11 is a diagram showing a fourth aspect (Example 4) of the laminated structure of the prepreg of the golf club shaft according to one embodiment of the present invention. [Figure 6] 1 is a diagram showing fifth, sixth and seventh aspects (Examples 5, 6 and 7) of the laminated structure of the prepreg of the golf club shaft according to one embodiment of the present invention. FIG. [Figure 7] 13 is a diagram showing an eighth embodiment and a ninth embodiment (Example 8 and Example 9) of the laminated structure of the prepreg of the golf club shaft according to one embodiment of the present invention. FIG. [Figure 8] FIG. 13 is a diagram showing a tenth embodiment (Example 10) of the laminated structure of the prepreg of the golf club shaft according to one embodiment of the present invention. [Figure 9] FIG. 11 is a diagram showing an eleventh embodiment (Example 11) of the laminated structure of the prepreg of the golf club shaft according to one embodiment of the present invention. [Figure 10] FIG. 2 is a diagram showing a laminated structure of prepregs of a golf club shaft of Comparative Example 1. [Figure 11] FIG. 13 is a diagram showing a laminated structure of prepregs of a golf club shaft of Comparative Example 2. [Figure 12] FIG. 13 is a diagram showing the laminated structure of the prepregs of the golf club shafts of Comparative Examples 3 and 4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] An embodiment of the present invention will be described. Aspect 1 of this embodiment is a golf club shaft formed by winding and heat-curing multiple layers of prepregs in which reinforcing fibers are impregnated with a thermosetting resin, wherein the prepregs include a 0° prepreg whose fiber direction is parallel to the longitudinal direction of the shaft, a 90° prepreg whose fiber direction is perpendicular to the longitudinal direction of the shaft, and a bias prepreg whose fiber direction is inclined with respect to the longitudinal direction of the shaft, and wherein the mass ratio of the 90° prepreg to the bias prepreg is 1.0 or more and the mass ratio of the 0° prepreg to the bias prepreg is 2.6 or more.

[0011] Aspect 2 of this embodiment is the golf club shaft of Aspect 1 above, characterized in that the mass ratio of the 90° prepreg to the bias prepreg is 1.5 or more.

[0012] Aspect 3 of this embodiment is the golf club shaft according to Aspect 1 or 2 above, characterized in that the mass ratio of the 0° prepreg to the bias prepreg is 3.0 or more.

[0013] Aspect 4 of this embodiment is a golf club shaft in any one of Aspects 1 to 3 above, characterized in that the total weight of the golf club shaft is 27 g or less.

[0014] A fifth aspect of this embodiment is a golf club comprising a golf club shaft according to any one of the first to fourth aspects, a club head and a grip attached thereto.

[0015] FIG. 1 is an exploded perspective view showing a schematic configuration of a golf club shaft 1 according to this embodiment, FIGS. 2 to 9 are views showing first to eleventh aspects of the prepreg laminate structure of the golf club shaft 1 according to this embodiment, and FIGS. 10 to 12 are views showing the prepreg laminate structures of the golf club shafts of Comparative Examples 1 to 4.

[0016] 2 to 12, "angle (°)" indicates the angle of the reinforcing fibers in each prepreg with respect to the longitudinal direction of the shaft (0°, 45°, or 90° in this embodiment). In the shape of each prepreg shown in Figs. 2 to 12, the left side of the drawing is the small diameter end (head side end, tip side) of the golf club shaft, and the right side is the large diameter end (grip side end, base end) of the golf club shaft.

[0017] The golf club shaft 1 according to this embodiment is made by winding multiple layers of prepreg in which reinforcing fibers are impregnated with a thermosetting resin and then heat curing the prepreg. As the reinforcing fibers, various materials such as carbon fibers, alumina fibers, aramid fibers, glass fibers, Tyranno fibers, carbon silicate fibers, and amorphous fibers can be used. As the thermosetting resin, various materials such as epoxy resins, unsaturated polyester resins, phenolic resins, vinyl ester resins, and PEEK resins can be used.

[0018] The golf club shaft 1 has a tapered shape in which the diameter gradually increases from the small diameter side at the tip to the large diameter side at the grip side. A club head (not shown) is attached to the small diameter end 11 of the golf club shaft 1, and a grip (not shown) is attached to the large diameter end 12 of the golf club shaft 1.

[0019] The prepregs include a 0° prepreg 21 in which the fiber direction of the reinforcing fibers is parallel to the longitudinal direction of the shaft, a 90° prepreg 22 in which the fiber direction of the reinforcing fibers is perpendicular to the longitudinal direction of the shaft, and a bias prepreg 23 in which the fiber direction of the reinforcing fibers is inclined with respect to the longitudinal direction of the shaft (see Figure 1).

[0020] In the golf club shaft 1 according to the present embodiment, the mass ratio of the 90° prepreg 22 to the bias prepreg 23 is 1.0 or more, preferably 1.5 or more, and particularly preferably 1.5 to 2.1. The mass ratio of the 0° prepreg 21 to the bias prepreg 23 is 2.6 or more, preferably 3.0 or more, and particularly preferably 3.0 to 4.2. When the mass ratio of the 90° prepreg 22 to the 0° prepreg 21 is within the above range, the strength of the golf club shaft 1 can be maintained even if the weight of the golf club shaft 1 is reduced. Note that in FIG. 1, the 0° prepreg 21, the 90° prepreg 22, and the bias prepreg 23 are shown as if they were each composed of one layer, but this is a schematic diagram for explaining the laminated structure of the golf club shaft 1, and the present invention is not limited to this embodiment. As described below, the golf club shaft 1 according to this embodiment may be formed by winding and laminating a plurality of 0° prepregs 21, a plurality of 90° prepregs 22, and a plurality of bias prepregs 23 (see FIGS. 2 to 9). Therefore, in this embodiment, the mass of the 0° prepreg 21, the mass of the 90° prepreg 22, and the mass of the bias prepreg 23 mean the total mass of the plurality of 0° prepregs 21, the total mass of the plurality of 90° prepregs 22, and the total mass of the plurality of bias prepregs 23, respectively, and the above mass ratio may be calculated using these total masses.

[0021] The laminated structure of each prepreg in the golf club shaft 1 according to this embodiment is not particularly limited as long as the above mass ratio is satisfied. For example, a first aspect of the laminated structure may be one in which a pair of bias prepregs P11, P12, a 0° prepreg P13 for reinforcing a tip end, a 90° prepreg P14 for reinforcing a base end, a triangular 0° prepreg (reinforcing prepreg) P15, a 90° prepreg P16, a 0° prepreg P17, a 90° prepreg P18, and a 0° prepreg P19 are wound and laminated in this order from the inner layer side (lower layer side) to the outer layer side (upper layer side) (see FIG. 2).

[0022] As a second aspect of the above laminated structure, for example, a pair of bias prepregs P21, P22, a 0° prepreg P23 for tip reinforcement, a 0° prepreg P24 for base reinforcement, a 90° prepreg P25, a 0° prepreg P26, a 90° prepreg P27, a 0° prepreg P28, and a triangular 0° prepreg (reinforcing prepreg) P29 are wound and laminated in order from the inner layer side (lower layer side) to the outer layer side (upper layer side) (see Figure 3).

[0023] As a third aspect of the above laminated structure, for example, a pair of bias prepregs P31, P32, a 0° prepreg P33 for tip reinforcement, a triangular 0° prepreg (reinforcing prepreg) P34, a 0° prepreg P35, a 90° prepreg P36, a 0° prepreg P37, a 90° prepreg P38, and a 90° prepreg P39 may be wound and laminated in this order from the inner layer side (lower layer side) to the outer layer side (upper layer side) (see Figure 4).

[0024] An example of a fourth aspect of the above laminated structure may be a laminate formed by winding and laminating, in order from the inner layer side (lower layer side) to the outer layer side (upper layer side), a 90° prepreg P41, a pair of bias prepregs P42, P43, a 0° prepreg P44 for tip reinforcement, a triangular 0° prepreg (reinforcing prepreg) P45, a 0° prepreg P46, a 0° prepreg P47, a 90° prepreg P48, and a 90° prepreg P49 (see Figure 5).

[0025] The fifth, sixth and seventh aspects of the laminated structure may be, for example, a laminate of a 90° prepreg P51, a pair of bias prepregs P52 and P53, a 0° prepreg P54 for reinforcing a tip end, a triangular 0° prepreg (reinforcing prepreg) P55, a 0° prepreg P56, a 90° prepreg P57, a 0° prepreg P58, a 90° prepreg P59 and a 90° prepreg P50, wound and laminated in this order from the inner layer side (lower layer side) to the outer layer side (upper layer side) (see FIG. 6). Note that the fifth to seventh aspects are such that the mass ratios of the 0° prepreg and the 90° prepreg to the bias prepreg are made different from each other by adjusting the dimensions of at least one of the wound and laminated prepregs (see Examples 5 to 7 in Table 1 below).

[0026] As the eighth and ninth aspects of the above laminate structure, for example, a pair of bias prepregs P61, P62, a 0° prepreg P63 for tip reinforcement, a 0° prepreg P64, a 90° prepreg P65, a 0° prepreg P66, a triangular 0° prepreg (reinforcing prepreg) P67, a 90° prepreg P68, and a 0° prepreg P69 may be wound and laminated in this order from the inner layer side (lower layer side) to the outer layer side (upper layer side) (see Figure 7).

[0027] An example of the tenth aspect of the above laminate structure may be a laminate structure in which, in order from the inner layer side (lower layer side) to the outer layer side (upper layer side), a 90° prepreg P71, a pair of bias prepregs P72, P73, a 90° prepreg P74, a 0° prepreg P75 for tip reinforcement, a triangular 0° prepreg (reinforcing prepreg) P76, a 0° prepreg P77, a 0° prepreg P78, a 90° prepreg P79, and a 90° prepreg P70 are wound and laminated (see Figure 8).

[0028] An eleventh aspect of the above laminate structure may be, for example, a laminate formed by winding and laminating, in order from the inner layer side (lower layer side) to the outer layer side (upper layer side), a bias prepreg P81 for base end reinforcing, a pair of bias prepregs P82, P83, a 0° prepreg P84 for tip end reinforcing, a triangular 0° prepreg (reinforcing prepreg) P85, a 0° prepreg P86, a 90° prepreg P87, a 0° prepreg P88, a 90° prepreg P89, and a 90° prepreg P80 (see Figure 9).

[0029] In the golf club shaft 1 according to this embodiment, the number of turns (number of plies) of each prepreg in the laminated structure may be appropriately set so that the mass ratio of the 90° prepreg 22 and the mass ratio of the 0° prepreg 21 to the bias prepreg 23 are within a predetermined range. For example, the number of turns (number of plies) of each prepreg may be at least one turn (one ply), and the numbers of turns (number of plies) of all the prepregs in the laminated structure may be the same, or the number of turns (number of plies) of at least one prepreg may be different.

[0030] The total weight of the golf club shaft 1 according to this embodiment may be, for example, 27 g or less, and is preferably 26.5 g or less. According to this embodiment, even if the total weight of the golf club shaft 1 is 27 g or less, the strength of the golf club shaft 1 can be maintained. Note that the total weight of the golf club shaft 1 in this embodiment refers to the weight of the golf club shaft 1 having the above-mentioned laminated structure in which a plurality of prepregs are wound and laminated, and which has been subjected to a paint treatment.

[0031] The golf club shaft 1 according to this embodiment can be manufactured by winding each prepreg around a tapered rod-shaped mandrel (rod-shaped core metal) in order from the inner layer side (lower layer side) to the outer layer side (upper layer side) according to the above-mentioned laminated structure, heat-curing them, and then pulling out the rod-shaped mandrel. The golf club shaft 1 manufactured in this manner may be subjected to a painting treatment.

[0032] The fiber directions of the 90° prepreg and the base end reinforcing 90° prepreg in the first to eleventh aspects of the above laminate structure are perpendicular to the shaft longitudinal direction of the golf club shaft 1. The fiber directions of the pair of bias prepregs and the base end reinforcing bias prepreg are inclined at 40 to 50°, preferably 45°, with respect to the shaft longitudinal direction of the golf club shaft 1. The fiber directions of the 0° prepreg, the tip end reinforcing 0° prepreg, the base end reinforcing 0° prepreg and the triangular 0° prepreg are parallel to the shaft longitudinal direction of the golf club shaft 1.

[0033] The 90° prepreg, the pair of bias prepregs and the 0° prepreg are made up of full length layers spanning the entire length of the golf club shaft 1, and are formed into a trapezoidal shape that narrows from the large diameter end (grip side end, base end) to the small diameter end (head side end, tip end) so that when wound around a rod-shaped mandrel M, the number of turns is the same along the entire length of the golf club shaft 1.

[0034] The pair of reinforcing bias prepregs and the 0° prepreg for tip reinforcement are wound only around the vicinity (part of the longitudinal direction) of the small diameter end (tip) of the golf club shaft 1 to reinforce the vicinity (part of the longitudinal direction) of the small diameter end (tip) of the golf club shaft 1. The triangular 0° prepreg is intended to make the small diameter end (tip) of the golf club shaft 1 a straight section that corresponds to the hosel diameter of the club head (not shown).

[0035] According to the golf club shaft 1 of this embodiment, the mass ratio of the 90° prepreg to the bias prepreg is 1.0 or more, and the mass ratio of the 0° prepreg to the bias prepreg is 2.6 or more, so that the strength of the golf club shaft 1 can be maintained even if the golf club shaft 1 is made lighter.

[0036] The above-described embodiments are described for the purpose of facilitating understanding of the present invention, and are not described for the purpose of limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design modifications and equivalents that fall within the technical scope of the present invention. EXAMPLES

[0037] The present invention will be described in more detail below by way of examples, but the present invention is not limited to the following examples and test examples.

[0038] [Example 1] Three-point bending strength test A three-point bending strength test was conducted on the golf club shafts 1 of the above first to eleventh embodiments (see Examples 1 to 11, Figs. 2 to 9) and the golf club shafts of Comparative Examples 1 to 4 (see Figs. 10 to 12). The three-point bending strength test was conducted by applying loads to positions 90 mm (T-90), 175 mm (T-175), and 525 mm (T-525) from the tip of the shaft and a position 175 mm (B-175) from the butt of the shaft, and measuring the load when the shaft broke. The results are shown in Table 1.

[0039] [Table 1]

[0040] In the three-point bending strength test, if the bending strength at each position (T-90, T-175, T-525, B-175) is 300N or more, it can be evaluated as having sufficient strength. As is clear from the results shown in Table 1 above, the golf club shafts 1 of Examples 1 to 11 can be evaluated as having sufficient strength while being lighter than the golf club shaft of Comparative Example 1. On the other hand, the golf club shafts of Comparative Examples 2 to 4 can be evaluated as having insufficient strength, particularly at the positions T-175, T-525, and B-175. From these results, it was found that the strength of the golf club shaft can be maintained even if the weight of the golf club shaft is reduced by setting the mass ratio of the 90° prepreg to the bias prepreg to 1.0 or more, preferably 1.5 or more, and the mass ratio of the 0° prepreg to the bias prepreg to 2.6 or more, preferably 3.0 or more. [Explanation of symbols]

[0041] 1. Golf club shaft 21…0° prepreg 22…90° prepreg 23...Bias prepreg

Claims

1. A golf club shaft made by winding multiple layers of prepreg in which reinforcement fibers are impregnated with a thermosetting resin and then heat-curing the layers, The prepregs include a 0° prepreg whose fiber direction is parallel to the longitudinal direction of the shaft, a 90° prepreg whose fiber direction is perpendicular to the longitudinal direction of the shaft, and a bias prepreg whose fiber direction is inclined with respect to the longitudinal direction of the shaft, The mass ratio of the 90° prepreg to the bias prepreg is 1.0 or more, A golf club shaft, wherein a mass ratio of the 0° prepreg to the bias prepreg is 2.6 or more.

2. 2. The golf club shaft according to claim 1, wherein a mass ratio of the 90° prepreg to the bias prepreg is 1.5 or more.

3. 3. The golf club shaft according to claim 1, wherein a mass ratio of the 0° prepreg to the bias prepreg is 3.0 or more.

4. 3. The golf club shaft according to claim 1, wherein the total weight of the golf club shaft is 27 g or less.

5. 3. A golf club comprising the golf club shaft according to claim 1, a club head and a grip attached to the golf club shaft.

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