JP2009060983A - Golf club shaft - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the torque and to enhance the strength of a golf club shaft while retaining the lightness and restraining the increase of the flex of the golf club shaft. <P>SOLUTION: The golf club shaft has at least six prepreg layers of the full length layers disposed in the full length of the shaft, and at least two sets of bias-set layers with inner/outer bias layers crossing reinforced fiber layered as the full length layers. When one half on the inner side of the shaft of the full length layers are divided as inner layer parts and the other half on the outer side of the shaft as outer layer parts, the outer bias layer of at least one set of the bias layers is disposed in the outer layer parts, and the inner bias layer of at least another set of the bias layers is disposed in the inner layer parts. A hoop layer is disposed in contact with the bias layer in the outer layer parts, and a straight layer is disposed as the outermost full length layer in the outer layer parts. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a golf club shaft, and more particularly, to improve the strength, directionality, and flight distance of a lightweight golf club shaft.

  In recent years, golf club shafts and heads have been reduced in weight in order to improve the flight distance of the hit ball. Therefore, the material of golf club shafts is mainly made of fiber reinforced resin made of laminated prepreg impregnated with reinforcing fibers such as carbon, which is lightweight, high in specific strength and high rigidity, from steel, which has been the mainstream in the past. ing.

  In the golf club shaft made of fiber reinforced resin laminated with the prepreg, the bias layer in which the orientation angle of the reinforcing fiber is inclined with respect to the shaft axis affects the torque. Therefore, since the straight layer in which the orientation angles of the reinforcing fibers are substantially parallel affects the flex, the arrangement in the outer layer portion of the shaft is generally used.

It is common practice to reduce the weight of the shaft by reducing the volume (weight per unit area and number of layers) of the prepreg, but this method has a problem in that it tends to cause a decrease in strength and increases torque and flex. is there.
That is, the head speed is generally increased by reducing the weight of the shaft, but when the torque is large, the return of the head is delayed, which is a major cause of deterioration in directionality. On the other hand, when the flex is large, the shaft is soft, so that it bends too much, resulting in energy loss and hindering an increase in flight distance.

As a method for reducing the torque, an increase in the basis weight of the bias layer that affects the torque or an increase in the elasticity of the fiber type is generally used.
As a method for reducing the flex, generally, the resin weight per unit area of the straight layer that affects the flex is increased, or the fiber type is made highly elastic.
However, an increase in the basis weight of the resin of the prepreg is contrary to weight reduction, and increasing the elasticity of the fiber type has a problem in that the strength is lowered when the tensile elastic modulus of the fiber exceeds 30 t / mm ² .
Thus, it is a problem to obtain a desired flex and torque while maintaining light weight and strength.

  Regarding this type of problem, in Japanese Patent Application Laid-Open No. 2003-180890 (Patent Document 1), by arranging a bias layer of ± 20 ° to 65 ° in the middle portion of the shaft, vibration absorption is maintained while maintaining light weight. It has been proposed to improve the directionality. However, in this case, the addition of a bias layer is contrary to weight reduction, and there is room for improvement because bending strength and crushing strength are liable to be reduced compared to the case where a bias layer is disposed instead of a straight layer or a hoop layer.

In JP-A-2004-305332 (Patent Document 2), the inner layer of the shaft is formed of a bias layer having a fiber orientation angle of ± 35 ° to 55 °, the outer layer of the shaft is formed of a straight layer, and It has been proposed to form a bias layer having a fiber orientation angle of ± 5 ° to 30 ° on at least a part of the outermost layer.
Accordingly, the torsional rigidity can be increased by the inner bias layer, the bending rigidity can be increased by the outer straight layer, the deformation amount of the fiber can be reduced by the outermost bias layer, and the bending strength can be increased. However, the outermost layer is polished in relation to the coating, and the bias layer is polished, so that there is a possibility that the desired strength and torque may not provide sufficient performance.

JP 2003-180890 A JP 2004-305332 A

  The present invention has been made in view of the above problems, and it is an object of the present invention to provide a golf club shaft that has light weight, has a desired flex and torque in a well-balanced manner, and has excellent flight distance, hitting directionality, and strength. .

In order to solve the above problems, the present invention provides a golf club shaft comprising a laminate of prepregs,
Comprising at least six full-length layers consisting of the prepregs arranged over the entire length of the shaft,
As the full length layer, the orientation angle θ ° with respect to the shaft axis of the reinforcing fiber is in the range of ± 25 ° or more and ± 65 ° or less, and one bias layer in which the orientation angle is + θ ° and one layer that is −θ °. And at least two bias set layers that are laminated as inner and outer bias layers so that the reinforcing fibers cross each other.
If the half of the inner circumferential side of the shaft is divided into the inner layer portion and the outer half of the shaft outer circumferential portion is divided into the outer layer portion, the outer bias layer of at least one pair of the bias set layers is arranged in the outer layer portion. On the other hand, the inner bias layer of at least one other bias set layer is disposed in the inner layer portion,
Further, a hoop layer whose orientation angle with respect to the shaft axis of the reinforcing fiber is within a range of ± 80 ° or more and 90 ° or less is disposed in contact with the bias layer of the outer layer portion, and
The outermost full length layer of the outer layer portion is a golf club shaft characterized in that the orientation angle of the reinforcing fiber with respect to the shaft axis is in the range of 0 ° to ± 10 °.

The number of laminated prepregs is a count of one circumferential layer of one prepreg as one layer.
Further, when the number of the full length layers is an even number, the half is divided into an inner layer portion and an outer layer portion, but in the case of an odd number, an intermediate layer is set as an intermediate layer portion, and half of the intermediate layer portion is excluded from the inner layer portion. Part and outer layer part.

As described above, out of at least two bias set layers, the outer bias layer of one set of bias set layers is disposed in the outer layer portion, while the inner bias layer of the other one set of bias set layers is It arrange | positions in the said inner layer part.
Specifically, in one set of bias set layers, both the outer bias layer and the inner bias layer are disposed in the outer layer portion, the outer bias layer is disposed in the outer layer portion, and the inner bias layer is the middle layer portion or the inner layer portion. There are three patterns in the case of arranging in the section.
Further, in another set of bias set layers, both the outer bias layer and the inner bias layer are arranged in the inner layer portion, the inner bias layer is arranged in the inner layer portion, and the outer bias layer is in the middle layer portion or the outer layer portion. There are three patterns when arranged in
Any pattern may be used, but as described above, at least the outer bias layer of one bias set layer is positioned in the outer layer portion, and the inner bias layer of the other bias set layer is positioned in the inner layer portion, thereby forming a stacked configuration. Balance layers are arranged in a well-balanced manner on the inner and outer peripheral sides of the shaft.

  In a normal shaft, the bias layer that is often arranged on the center side (that is, the inner layer side) is divided, and as described above, the golf club shaft of the present invention is arranged in a balanced manner in the inner layer portion and the outer layer portion. With this laminated structure, it is possible to reduce the torque value without increasing the flex while maintaining the light weight, and it is possible to improve the hitting direction and the flight distance.

Further, the inner bias layer and the outer bias layer constituting the bias set layer contribute to the improvement of the bending strength as the angle of the reinforcing fiber with respect to the shaft axis is smaller, and contribute to the improvement of the crushing strength as it is larger. In the present invention, the shaft strength is improved in a well-balanced manner by changing / adjusting the fiber angle of the bias layer within a range of ± 25 ° to 65 °.
The orientation angle of the reinforcing fibers of the bias layer is within the range of ± 25 ° or more and 65 ° or less because when the orientation angle is less than ± 25 ° or greater than ± 65 °, it deviates from the shaft twisting direction, so that a desired torque is obtained. This is because it is not obtained and the hitting directionality cannot be improved.
The bias layer may be laminated by laminating a prepreg having an orientation angle of + θ ° and a prepreg having −θ °, or by laminating one and then winding the other. You may laminate.

In the shaft of the present invention, the hoop layer is disposed in contact with the bias layer disposed in the outer layer portion. The hoop layer with the reinforcing fiber in the direction substantially orthogonal to the shaft axis has a cross-sectional deformation suppressing performance, and improves the crushing rigidity and crushing strength without changing the flex, resulting in an improvement in the three-point bending strength. Has characteristics.
The hoop layer is disposed in contact with the bias layer disposed in the outer layer portion, and the bias layer in contact with the hoop layer may be an outer bias layer in the bias set layer or an inner bias layer. However, in order to more effectively exhibit the cross-section deformation suppressing performance by the hoop layer, it is most preferable that the hoop layer is disposed in contact with the outer peripheral surface of the outer bias layer among the bias set layers disposed in the outer layer portion.
Thus, by arranging the hoop layer in contact with the bias layer arranged in the outer layer portion, the cross-sectional deformation suppressing performance of the hoop layer can suppress the cross-sectional deformation in the torsional direction, and the torque is more effectively reduced. It is possible to further improve the hitting directionality.

  Furthermore, in the shaft of the present invention, since the straight layer is arranged in the outermost full length layer of the outer layer portion, the bias layer is not affected by polishing, and sufficient performance in strength and torque is exhibited. Can do.

  The shaft of the present invention has a laminated structure in which the bias set layer, the hoop layer, and the straight layer are arranged as described above, so that even a lightweight shaft has excellent strength, and a desired flex and torque are set in a balanced manner. The hitting distance and directionality can be improved. In addition, the combination of fiber angles can improve the strength while maintaining the reduced torque.

The weight of the shaft is preferably 50 g or more and 70 g or less.
The reason for this is that if the weight is less than 50 g, the center of gravity of the shaft is on the head side. Therefore, when adjusting the club balance, it can be adjusted only to a heavy balance. This is because the speed does not increase and the flight distance decreases.

The prepreg used for the hoop layer preferably has a tensile elastic modulus of the reinforcing fiber of 30 t / mm ^{2 to} 80 t / mm ² and a resin content of 30% to 40%.
Are you tensile modulus of the reinforcing fibers hoop layer and 30~80t / mm ² is, 30t / mm not obtained the required cross-sectional deformation suppressing performance is less than ^2, it exceeds 80t / mm ^2, the elasticity of the fibers This is because it becomes too strong and it becomes difficult to adhere to the laminate.
The “tensile modulus” is measured in accordance with JIS R7601: 1986 “Carbon fiber test method”.
Also, the resin content of the hoop layer is set to 30% or more and 40% or less because if less than 30%, the lamination adhesive strength of the hoop layer decreases, and if it exceeds 40%, the hoop layer becomes too thick and the weight increases. Due to inviting.

When the orientation angle of the reinforcing fibers of the bias set layer in the inner layer portion is ± θ1 ° and the orientation angle of the reinforcing fibers of the bias set layer in the outer layer portion is ± θ2 °, θ2 / θ1 is in the range of 1 to 2 It is preferable to be within.
Thus, by setting the fiber angle ratio θ2 / θ1 of the inner and outer bias set layers, the strength can be improved according to the weight or thickness of the shaft. That is, θ2 / θ1 is set to 1 or more and 2 or less. If it is less than 1, the flex value can be maintained, but the bending strength also decreases as the strength in the crushing direction decreases. Although it can be maintained, the flex becomes too large, resulting in a decrease in flight distance due to energy loss.
The lower limit of θ2 / θ1 is more preferably 1.2 or more, further 1.3 or more, and the upper limit is preferably 1.8 or less, more preferably 1.5 or less.

The fiber angle θ1 of the bias set layer of the inner layer portion is preferably 25 ° or more and 50 ° or less, more preferably 25 ° or more and 45 ° or less, particularly 25 ° or more and 40 ° or less, because the bending strength is improved as the smaller one. Is preferred.
As the fiber angle θ2 of the bias set layer of the outer layer portion is larger, the strength in the crushing direction is improved, and in the light shaft with a thin wall thickness, the bending strength is improved with the strength in the crushing direction. Or less, more preferably 45 ° to 65 °, particularly preferably 50 ° to 65 °.

The ratio T2 / T1 of the total thickness T1 of the bias set layer in the inner layer portion and the total thickness T2 of the bias set layer in the outer layer portion is preferably in the range of 1 to 1.4.
This makes it possible to reduce the torque while maintaining the shaft strength.
That is, the thickness ratio T2 / T1 is set to 1 or more and 1.4 or less because if it is less than 1, the effect of lowering the torque is small, and the directionality is not improved. Although it is a difficult shaft, the straight layer is relatively disposed inward, resulting in an increase in flex and a decrease in strength. Preferably, the lower limit of T2 / T1 is 1.1 or more.

  When the number of the full length layers is an odd number, it is preferable that an intermediate layer is an intermediate layer portion and a straight layer is disposed as the intermediate layer portion. When the straight layer is disposed as the middle layer in this manner, the increase in flex can be suppressed and the torque can be reduced.

  Examples of the resin used for the prepreg include a thermosetting resin and a thermoplastic resin. From the viewpoint of strength and rigidity, a thermosetting resin is preferable, and an epoxy resin is particularly preferable.

Examples of the thermosetting resin include epoxy resins, unsaturated polyester resins, phenol resins, melamine resins, urea resins, diallyl phthalate resins, polyurethane resins, polyimide resins, silicon resins, and the like.
As thermoplastic resins, polyamide resins, saturated polyester resins, polycarbonate resins, ABS resins, polyvinyl chloride resins, polyacetal resins, polystyrene resins, polyethylene resins, polyvinyl acetate resins, AS resins, methacrylic resins , Polypropylene resin, fluorine resin and the like.

  The reinforcing fiber used in the prepreg is preferably a carbon fiber because it has a small specific gravity and a high elastic modulus and strength, but in addition, a fiber generally used as a high-performance reinforcing fiber is used. Examples thereof include graphite fiber, aramid fiber, silicon carbide fiber, alumina fiber, boron fiber, and glass fiber.

  As described above, according to the present invention, the bias layer that affects the torque is not increased, but is divided into the inner layer portion and the outer layer portion in a well-balanced manner, and the straight layer is arranged in the outermost full length layer. By suppressing the increase in weight and maintaining the strength and flex, the torque can be reduced. Further, the hoop layer is disposed in contact with the outer bias set layer, whereby the hoop layer has a cross section. The deformation suppression performance can contribute to the torque reduction and the cross-sectional deformation in the torsional direction is suppressed, so that the torque can be further effectively reduced. Therefore, it is possible to obtain a golf shaft having a good balance of lightness, excellent strength, excellent flight distance and directionality.

  In addition, by changing and adjusting the fiber angle of the bias layer within the range of ± 25 ° to 65 °, the bending strength and crushing strength can be increased and decreased while maintaining low torque, so the desired torque and shaft strength are balanced. Can get well.

Further, by setting the ratio θ2 / θ1 between the fiber angle θ1 ° of the inner bias set layer and the fiber angle θ2 ° of the outer bias set layer to 1 or more and 2 or less, the desired crushing strength and the desired flex can be obtained in a balanced manner. be able to.
Further, by setting the ratio T2 / T1 of the thickness T1 of the inner bias set layer and the thickness T2 of the outer bias set layer to 1 or more and 1.4 or less, a torque reduction effect and a desired flex can be obtained in a balanced manner. Can do.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 3 show a shaft 10 for a golf club according to a first embodiment of the present invention.

The shaft 10 is composed of a tapered long tubular body made of a laminate of the prepregs 21 to 32 shown in FIG. 2, and the eight layers of the prepregs 22, 23, and 25 to 30 of the prepregs 21 to 32 are the entire length of the shaft. The full length layer (1-8) arrange | positioned in is formed.
As shown in FIG. 1, a head 13 is attached to the head-side tip 11 on the small-diameter side of the shaft 10, and a grip 14 is attached to the grip-side rear end 12 on the large-diameter side. In the present embodiment, the total length of the shaft 10 is 1195 mm, and the shaft weight is 63 g.

  As shown in FIG. 2, the shaft 10 is made of polyethylene or polyethylene terephthalate after the prepregs 21 to 32 are wound around the mandrel 20 one by one by the sheet winding method in the order of the prepregs 21 to 32, and then laminated. Lapping is performed while applying pressure with a tape such as the like, and this is heated and pressed in an oven to cure the resin and integrally molded, and then the mandrel 20 is pulled out to manufacture the shaft 10. The shaft surface is polished and then cut at both ends and painted.

The prepregs 21 to 32 constituting the shaft 10 are all impregnated with reinforced fibers F21 to F32 made of carbon fibers and impregnated with epoxy resin, and the resin content is 25% except for the prepreg of the hoop layer, The prepreg of the hoop layer is 30% to 40%. The tensile elastic modulus of the reinforcing fibers F21 to F32 is 30 t / mm ² .

Specifically, the prepreg 21 is partially disposed at the head-side tip, has a length of 197 mm, and the reinforcing fiber F21 has an orientation angle of 0 ° with respect to the shaft axis.
Both the prepregs 22 and 23 are arranged along the entire length of the shaft, the reinforcing fiber F22 has an orientation angle of −45 ° with respect to the shaft axis, and the reinforcing fiber F23 has an orientation angle of + 45 ° with respect to the shaft axis. Yes. The two fiber-reinforced prepregs 22 and 23 are wound in a state of being overlapped and bonded so that the reinforcing fibers F22 and F23 cross each other, thereby forming a bias set layer A1 on the inner layer side described later.
The prepreg 24 is partially disposed at the head-side tip, has a length of 267 mm, and the reinforcing fiber F24 has an orientation angle of 0 ° with respect to the shaft axis, forming a straight layer.
Both the prepregs 25 and 26 are arranged along the entire length of the shaft, and the reinforcing fibers F25 and 26 form a straight layer with an orientation angle of 0 ° with respect to the shaft axis.
Both the prepregs 27 and 28 are disposed along the entire length of the shaft, the reinforcing fiber F27 has an orientation angle of −45 ° with respect to the shaft axis, and the reinforcing fiber F28 has an orientation angle of + 45 ° with respect to the shaft axis. Yes. The two fiber-reinforced prepregs 27 and 28 are wound in a state where the two reinforcing fibers F27 and F28 are overlapped and bonded so as to cross each other, thereby forming a bias set layer A2 on the outer layer side described later.
The prepreg 29 is disposed over the entire length of the shaft, and the reinforcing fiber F29 forms an hoop layer B with an orientation angle of 90 ° with respect to the shaft axis.
The prepreg 30 is disposed over the entire length of the shaft, and the reinforcing fibers F30 form an outermost straight layer C described later with an orientation angle of 0 ° with respect to the shaft axis.
The prepreg 31 is partially disposed at the head-side tip, has a length of 217 mm, and the reinforcing fiber F31 has an orientation angle of 0 ° with respect to the shaft axis.
The prepreg 32 is partially disposed at the head-side tip, has a length of 167 mm, and the reinforcing fiber F32 has an orientation angle of 0 ° with respect to the shaft axis.

As described above, the shaft 10 includes a total of eight full-length layers including the prepregs 22, 23, 25, 26, 27, 28, 29, and 30.
Specifically, as shown in FIG. 3, the inner layer portion I composed of the four full length layers 22, 23, 25, and 26 on the inner peripheral side of the shaft, and the full length layers 27, 28, 29, 30, and 31 on the outer peripheral side four layers. The inner layer side bias set layer A1 formed by the prepregs 22 and 23 is disposed in the inner layer portion I. In the bias set layer A1 in the inner layer portion, the prepreg 22 is an inner bias layer, and the prepreg 23 is an outer bias layer.
On the other hand, the bias set layer A2 on the outer layer side formed by the prepregs 27 and 28 is disposed in the outer layer portion II. In the bias set layer A2 of the outer layer portion, the prepreg 27 serves as an inner layer side bias layer, and the prepreg 28 serves as an outer layer side bias layer.

  In the outer layer portion II, the hoop layer B formed of the prepreg 29 is disposed in contact with the outer peripheral surface of the outer bias layer 28 of the bias set layer A2 of the outer layer portion. Moreover, the prepreg 30 is arrange | positioned as mentioned above in the outermost full length layer of the outer layer part II, and it is set as the outermost full length straight layer C. As shown in FIG.

The orientation angle of the reinforcing fibers of the bias set layer A1 of the inner layer portion I is ± 45 ° is ± 45 °, and the orientation angle of the reinforcing fibers of the bias set layer A2 of the outer layer portion II is ± 45 °. .
Therefore, θ2 / θ1 is 1.

  The total thickness (T1) of the bias set layer A1 in the inner layer portion I and the total thickness (T2) of the bias set layer A2 in the outer layer portion II are both 0.290 mm.

  The shaft 10 having the above-described configuration does not increase the number of bias layers or the prepreg weight per unit area that affects the torque. Instead of the full-length bias layer, which is conventionally disposed only in the shaft inner layer portion, as the inner layer portion I. The bias set layer A1 is arranged, and the bias set layer A2 is arranged in the outer layer part II to be divided. Thus, since it arranges with good balance not only in the inner layer part I but also in the outer layer part II, it becomes possible to reduce the torque without increasing the shaft weight and maintaining the flex and strength. .

  Further, since the hoop layer B is disposed in contact with the outer peripheral surface of the prepreg 28 of the outer bias layer of the bias set layer A2 of the outer layer portion II, the cross-section deformation suppressing performance of the hoop layer B is effectively exhibited. As a result, the strength of the hoop layer B can be improved, and the cross-sectional deformation suppression performance of the hoop layer B can be contributed to the torque reduction performance of the bias set layer A2 of the outer layer portion II that greatly affects the torque. Can be made.

  Furthermore, since the straight layer C made of the prepreg 30 is disposed as the outermost full length layer, the bias set layer A2 of the outer layer part II is not affected by the polishing required for the painting, and the torque reduction effect Can be fully demonstrated.

As a result, it is possible to realize a shaft that is lightweight and has excellent strength, flight distance, and directionality.
Furthermore, the orientation angles of the reinforcing fibers F22, F23, F27, and F28 of the bias set layers A1 and A2 in the inner and outer layers are all + 45 ° or −45 °, and are within a range of ± 25 ° to 65 °. Therefore, the torque reduction effect can be sufficiently exhibited, and the shaft strength in the bending direction and the crushing direction can be increased in a well-balanced manner.

Further, the ratio θ2 / θ1 of the orientation angles of the reinforcing fibers F27 and F28 of the bias set layer A2 of the outer layer II to the orientation angles of the reinforcing fibers F22 and F23 of the bias set layer A1 of the inner layer portion I is 1, and is 1-2. Therefore, the shaft strength can be increased while suppressing an increase in flex.
Further, the ratio T2 / T1 of the thickness T2 of the bias set layer A2 of the outer layer part II to the thickness T1 of the bias set layer A1 of the inner layer part I is 1, which is within the range of 1 to 1.4, so that the flex is increased. The torque can be reduced in a well-balanced manner while suppressing the above.

Furthermore, the hoop layer B has a tensile elastic modulus of the reinforcing fiber F29 of 30 t / mm ² and a resin content of 37.5%. Realized in a well-balanced manner.

FIG. 4 shows a second embodiment of the present invention.
In the present embodiment, the prepreg 33 serving as the hoop layer B is disposed in contact with the inner peripheral surface of the prepreg 27 constituting the inner bias layer of the bias set layer A2 of the outer layer portion II. Further, the prepreg 30 constituting the straight layer C of the outermost full length layer is disposed on the outer peripheral surface of the prepreg 28 constituting the outer bias layer of the bias set layer A2.

That is, the winding order of the prepreg in the manufacturing process is as follows. First, the prepregs 21 to 26 are sequentially laminated from the inside, and then the prepreg 33 with an orientation angle of 90 ° with respect to the shaft axis of the reinforcing fiber F33 is wound to form the hoop layer B. Next, the prepregs 27 and 28 are wound to form the bias set layer A2, and then the prepregs 30 to 32 are sequentially laminated. Thus, a total of eight full length layers 1 to 8 are formed by the prepregs 22, 23, 25, 26, 33, 27, 28, 30.
Other configurations are the same as those of the first embodiment, and the same reference numerals are given and description thereof is omitted.

  Also in the present embodiment, since the hoop layer B is disposed in contact with the bias set layer A2 of the outer layer part II that greatly affects the torque, the cross-sectional deformation suppression performance of the hoop layer B is effectively contributed to the torque reduction. be able to.

FIG. 5 shows a third embodiment of the present invention.
In the shaft of this embodiment, the prepregs 22, 23, 25, 27, 28, 29, 34, and 30 form a total length of 8 layers.
Of the bias set layer A2 composed of the prepregs 27 and 28, the prepreg 28 serving as the outer bias layer is disposed in the outer layer portion II, while the prepreg 27 serving as the inner bias layer is disposed in the inner layer portion I. That is, in the bias set layer A2, the inner bias layer is disposed in the inner layer portion, the outer bias layer is disposed in the outer layer portion, and the inner layer portion and the outer layer portion are separately disposed.
Further, a bias set layer A1 composed of the prepregs 22 and 23 is disposed in the inner layer portion I.
In the inner layer portion I, a prepreg 25 serving as a straight layer is disposed as a full length layer on the outer periphery of the prepreg 23 serving as an outer bias layer of the bias set layer A1, and a bias set layer A2 is disposed on the outer periphery of the prepreg 25. .
In the outer layer portion II, a prepreg 29 to be a hoop layer B is disposed on the outer periphery of the prepreg 28 of the outer bias layer of the bias set layer A2. Between the hoop layer B and the outermost full length straight layer C made of the prepreg 30, a full length straight layer made of the prepreg 34 having an orientation angle of 0 ° with respect to the shaft axis of the reinforcing fiber F 34 is arranged.

That is, the winding order of the prepreg in the manufacturing process is as follows. First, the prepregs 21 to 25 are sequentially laminated from the inside, then the prepregs 27 and 28 are wound to form the bias set layer A2, and then the prepreg 29 is wound to form the hoop layer B. Then, the prepreg 30 is wound next to the prepreg 34 to form the outermost full length straight layer C, and finally, the prepregs 31 and 32 are sequentially stacked on the head side tip.
Other configurations are the same as those of the first embodiment, and the description thereof will be omitted by assigning the same reference numerals.

Also in this embodiment, the bias set layer A1 formed by the prepregs 22 and 23 is disposed in the inner layer portion I, and the prepreg 28 of the outer bias layer of the bias set layer A2 formed by the prepregs 27 and 28 is the outer layer portion II. The bias layer is distributed in the inner layer portion I and the outer layer portion II.
Further, the hoop layer B is disposed in contact with the outer peripheral surface of the outer bias layer of the bias set layer A2 located in the outer layer part II, and the outermost peripheral straight layer C is provided. Thereby, torque can be effectively reduced in a balanced manner while suppressing an increase in weight and an increase in flex.

FIG. 6 shows a fourth embodiment of the present invention.
In this embodiment, a total of nine full length layers are provided by the prepregs 22, 23, 25, 26, 35, 27, 28, 29, and 30. Of these nine full-length layers, the four layers on the shaft center side are the inner layer portion I, the outer peripheral side four layers are the outer layer portion II, and the intermediate prepreg 35 is the middle layer portion III.
The prepreg 35 of the middle layer portion III is a prepreg that forms a straight layer in which the orientation angle of the reinforcing fiber F35 with respect to the shaft axis direction is 0 °.

  A bias set layer A1 composed of prepregs 22 and 23 is disposed in the inner layer portion I, and a bias set layer A2 composed of prepregs 27 and 28 is disposed in the outer layer portion II, and the bias set layer A2 of the outer layer portion II is disposed. A prepreg 29 to be the hoop layer B is disposed in contact with the outer peripheral surface of the prepreg 28 of the outer bias layer, and a prepreg 30 to be the straight layer C of the outermost full length layer is disposed on the outer peripheral surface of the prepreg 29. As a result, the torque can be reduced while minimizing the increase in flex.

(Example)
Hereinafter, Examples 1 to 13 and Comparative Examples 1 to 7 of the golf club shaft of the present invention will be described in detail.
As shown in Table 1 and Table 2 below, Examples 1 to 13 shown in Table 1 are all provided with 8 full length layers 1 to 8, and Comparative Examples 1 to 3 shown in Table 2 are 7 full length layers. It was set as the layer, and Comparative Examples 4-7 was made into 8 layers.
All the bias layers were ± 45 °, the hoop layer was 90 °, and the straight layer was 0 °.
Examples 1 to 13 and Comparative Examples 1 to 7 having different hoop layer presence or absence or hoop layer laminating position, bias layer laminating position, and thickness were produced, forward flex, torque, three-point bending strength, crushing The strength was measured, and the results are shown in Tables 1 and 2.

Each of Examples 1 to 13 and Comparative Examples 1 to 7 was prepared by a sheet winding manufacturing method using a prepreg manufactured by Mitsubishi Rayon Co., Ltd., which was impregnated with a carbon fiber as a reinforcing fiber and an epoxy resin. The same as one embodiment. Table 1 shows only the full length layers 1 to 8 (1 to 7).
In Examples 1 to 13 and Comparative Examples 1 to 7, the shaft length was 1195 mm, and the shaft weight and shaft balance of each Example and Comparative Example were set as shown in Table 1.

(Example 1)
The laminated structure of the prepreg is the same as that of the second embodiment, and the bias set layer A1 is disposed in the inner layer portion I, the bias set layer A2 is disposed in the outer layer portion II, and is brought into contact with the inner peripheral side of the bias set layer A2. The hoop layer B was disposed. A straight layer having a fiber angle of 0 ° was formed on the outermost full length layer. The fiber angle ratio θ2 / θ1 of the bias set layers A1 and A2 was set to 1.
For the full length layers 1, 2, 6, and 7, a product number “MR350C-175S” having a fiber tensile elastic modulus of 30 t / mm ² , a resin content of 25%, and a thickness of 0.145 mm was used. For the full length layers 3, 4, and 8, a product number “MR350C-150S” having a fiber tensile modulus of 30 t / mm ² , a resin content of 25%, and a thickness of 0.124 mm was used. For the full length layer 5 forming the hoop layer B, a product number “MR350C-025S” having a fiber tensile elastic modulus of 30 t / mm ² , a resin content of 37.5% and a thickness of 0.021 mm was used.
The inner layer bias set layer A1 had a thickness T1 of 0.290 mm, the outer layer bias set layer A2 had a thickness T2 of 0.290 mm, and T2 / T1 was set to 1. The thickness of the inner straight layer consisting of the full length layers 3 and 4 was 0.248 mm, and the thickness of the outer straight layer 8 consisting of the full length layer 8 was 0.124 mm.

(Example 2)
The laminated structure of the prepreg is the same as that of the first embodiment, the bias set layer A1 is disposed in the inner layer portion I, the bias set layer A2 is disposed in the outer layer portion II, and the outer periphery of the outer bias layer of the bias set layer A2 is in contact with it. The hoop layer B was arranged. Further, a straight layer having a fiber angle of 0 ° was disposed on the outermost full length layer 8. The fiber angle ratio θ2 / θ1 of the bias set layers A1 and A2 was set to 1.
The prepreg type used for each of the straight layer, the bias set layers A1 and A2, and the hoop layer B was the same as that of the first example.
The thickness T1 of the bias set layer A1 was 0.290 mm, the thickness T2 of the bias set layer A2 was 0.290 mm, and T2 / T1 was set to 1. Further, the thickness of the inner straight layer consisting of the full length layers 3 and 4 was 0.248 mm, and the thickness of the outer straight layer consisting of the full length layer 8 was 0.124 mm.

(Example 3)
The thickness ratio T2 / T1 of the bias set layers A1 and A2 of the inner layer portion and the outer layer portion was changed.
That is, the product number “MR350C-150S” having a fiber tensile elastic modulus of 30 t / mm ² , a resin content of 25%, and a thickness of 0.124 mm was used for the bias set layer A1 in the inner layer portion. For the bias set layer A2 in the outer layer part, a product number “MR350C-100S” having a fiber tensile modulus of 30 t / mm ² , a resin content of 25% and a thickness of 0.083 mm was used for two rounds.
Thus, the thickness T1 of the bias set layer A1 was set to 0.248 mm, the thickness T2 of the bias set layer A2 was set to 0.352 mm, and T2 / T1 was set to 1.42.
The other prepreg types used and the laminated structure of the prepreg were the same as those in Example 2.

Example 4
The thickness ratio T2 / T1 of the bias set layers A1 and A2 of the inner layer portion and the outer layer portion was changed.
That is, the product number “MR350C-100S” having a fiber tensile elastic modulus of 30 t / mm ² , a resin content of 25%, and a thickness of 0.083 mm was used for the inner layer bias set layer A1 for two rounds. For the bias set layer A2 of the outer layer portion, a product number “MR350C-150S” having a fiber tensile elastic modulus of 30 t / mm ² , a resin content of 25%, and a thickness of 0.124 mm was used.
Thus, the thickness T1 of the bias set layer A1 was set to 0.352 mm, the thickness T2 of the bias set layer A2 was set to 0.248 mm, and T2 / T1 was set to 0.70.
The other prepreg types used and the laminated structure of the prepreg were the same as those in Example 2.

(Example 5)
The thickness ratio T2 / T1 of the bias set layers A1 and A2 of the inner layer portion and the outer layer portion was changed.
That is, the product number “MR350C-125S” having a fiber tensile elastic modulus of 30 t / mm ² , a resin content of 25%, and a thickness of 0.103 mm was used for the bias set layer A1 of the inner layer portion. For the bias set layer A2 of the outer layer part, a product number “MR350C-125S” having a fiber tensile elastic modulus of 30 t / mm ² , a resin content of 25% and a thickness of 0.103 mm was used for two rounds.
Thus, the thickness T1 of the bias set layer A1 was set to 0.206 mm, the thickness T2 of the bias set layer A2 was set to 0.412 mm, and T2 / T1 was set to 2.
The other prepreg types used and the laminated structure of the prepreg were the same as those in Example 2.

(Example 6)
The thickness ratio T2 / T1 of the bias set layers A1 and A2 of the inner layer portion and the outer layer portion was changed.
That is, the product number “MR350C-100S” having a fiber tensile elastic modulus of 30 t / mm ² , a resin content of 25%, and a thickness of 0.083 mm was used for the inner layer bias set layer A1 for two rounds. For the bias set layer A2 in the outer layer portion, a product number “MR350C-125S” having a fiber tensile elastic modulus of 30 t / mm ² , a resin content of 25%, and a thickness of 0.103 mm was used.
Thereby, the thickness T1 of the bias set layer A1 was set to 0.352 mm, the thickness T2 of the bias set layer A2 was set to 0.412 mm, and T2 / T1 was set to 1.17.
The other prepreg types used and the laminated structure of the prepreg were the same as those in Example 2.

(Example 7)
The fiber angles of the bias set layers A1 and A2 in the inner layer portion and the outer layer portion were changed. That is, the fiber angles of the inner layer bias set layer A1 and the outer layer bias set layer A2 were both ± 30 °.
The type of prepreg used and the laminated structure of the prepreg were the same as those in Example 2.

(Example 8)
The fiber angles of the bias set layers A1 and A2 in the inner layer portion and the outer layer portion were changed. That is, the fiber angles of the bias set layer A1 in the inner layer portion and the bias set layer A2 in the outer layer portion were both ± 60 °. The type of prepreg used and the laminated structure of the prepreg were the same as those in Example 2.

Example 9
The fiber angle ratio θ2 / θ1 of the bias set layers A1 and A2 of the inner layer portion and the outer layer portion was changed. That is, the fiber angle θ1 of the bias set layer A1 in the inner layer portion was ± 30 °, the fiber angle θ2 of the bias set layer A2 in the outer layer portion was ± 60 °, and the fiber angle ratio θ2 / θ1 was 2. The type of prepreg used and the laminated structure of the prepreg were the same as those in Example 2.

(Example 10)
The fiber angle ratio θ2 / θ1 of the bias set layers A1 and A2 of the inner layer portion and the outer layer portion was changed. That is, the fiber angle θ1 of the bias set layer A1 in the inner layer portion was ± 30 °, the fiber angle θ2 of the bias set layer A2 in the outer layer portion was ± 45 °, and the fiber angle ratio θ2 / θ1 was 1.50. The type of prepreg used and the laminated structure of the prepreg were the same as those in Example 2.

(Example 11)
The fiber angle ratio θ2 / θ1 of the bias set layers A1 and A2 of the inner layer portion and the outer layer portion was changed. That is, the fiber angle θ1 of the bias set layer A1 in the inner layer portion was ± 45 °, the fiber angle θ2 of the bias set layer A2 in the outer layer portion was ± 60 °, and the fiber angle ratio θ2 / θ1 was 1.33. The type of prepreg used and the laminated structure of the prepreg were the same as those in Example 2.

Example 12
Among the full length layers 1 to 8, the laminated structure of the inner layer portion I was changed.
That is, as shown in FIG. 7, in the inner layer portion I, a straight layer having a fiber angle of 0 ° is disposed on the innermost full length layer 1, and a bias set layer A1 of the inner layer portion is disposed on the outer full length layers 2 and 3. The outer full length layer 4 is a straight layer, and the bias set layer A1 in the inner layer portion is sandwiched between the two straight layers.
The laminated structure of the prepreg of the outer layer part II was the same as in Example 2. The prepreg types used for the straight layer, the bias set layers A1 and A2, and the hoop layer B were also the same as those in Example 2.

(Example 13)
The laminated structure of the prepreg was the same as that of the third embodiment. That is, while the straight layer of the inner layer portion I is reduced by one layer, the straight layer of the outer layer portion II is increased by one layer, and the outer layer 5 of the bias set layer A2 of the outer layer portion is disposed in the outer layer portion II. 4 is arranged in the inner layer part I.
Specifically, an inner layer bias set layer A1 with a fiber angle of ± 45 ° was formed on the full length layers 1 and 2 in order from the inner peripheral side, and a straight layer with a fiber angle of 0 ° was formed on the full length layer 3. A bias set layer A2 having a fiber angle of ± 45 ° is formed on the full length layers 4 and 5, a hoop layer B having a fiber angle of 90 ° is formed on the full length layer 6, and a straight layer having a fiber angle of 0 ° is formed on the full length layers 7 and 8. Formed.
The prepreg type used for each of the straight layer, the bias set layers A1 and A2, and the hoop layer B was the same as that in Example 2.
The thickness T1 of the bias set layer A1 in the inner layer portion was 0.290 mm, the thickness T2 of the bias set layer A2 was 0.290 mm, and T2 / T1 was set to 1. The thickness of the inner straight layer consisting of the full length layer 3 was 0.124 mm, and the thickness of the outer straight layer consisting of the full length layers 7 and 8 was 0.248 mm.

(Comparative Example 1)
The bias set layers A1 and A2 were not divided into the inner layer portion and the outer layer portion, but were arranged so as to overlap the inner layer side, and no hoop layer was formed.
That is, as shown in FIG. 8, the laminated structure of the prepreg is a fiber angle of ± 45 ° 2 in the total length layers 1 to 4 forming the middle layer portion III from the inner layer portion I of the total length layers 1 to 7 of the total seven layers. A set of bias set layers A1 and A2 were arranged, and all of the full length layers 5 to 7 forming the outer layer portion II were straight layers having a fiber angle of 0 °.
The prepreg type used was a product number “TR350C-175S” having a fiber tensile elastic modulus of 24 t / mm ² , a resin content of 25%, and a thickness of 0.146 mm for the full length straight layer 5. The product number “MR350C-150S” having a fiber tensile elastic modulus of 30 t / mm ² , a resin content of 25%, and a thickness of 0.124 mm is used. The full length bias layers 1 to 4 have a fiber tensile elastic modulus of 30 t / mm ² and a resin content. A product number “MR350C-175S” having a rate of 25% and a thickness of 0.145 mm was used.
The two sets of bias set layers A1 and A2 were both 0.290 mm in thickness. The outermost straight layer made of the full length layers 6 and 7 had a thickness of 0.248 mm, and the inner straight layer made of the full length layer 5 had a thickness of 0.146 mm.

(Comparative Example 2)
The bias set layers A1 and A2 were not divided into the inner layer portion I and the outer layer portion II, but were arranged on the outer layer side, and the hoop layer was not formed.
That is, as shown in FIG. 9, the laminated structure of the prepreg is such that all of the total length layers 1 to 3 forming the inner layer portion I among the total length layers 1 to 7 of the total seven layers are straight layers having a fiber angle of 0 °, Two pairs of bias set layers A1 and A2 having a fiber angle of ± 45 ° were arranged on the full length layers 4 to 7 forming the part III to the outer layer part II.
As the prepreg type used, a product number “TR350C-175S” having a fiber tensile elastic modulus of 24 t / mm ² , a resin content of 25%, and a thickness of 0.146 mm was used for the innermost full length straight layer 4. For the full length straight layers 2 and 3, a product number “MR350C-150S” having a fiber tensile elastic modulus of 30 t / mm ² , a resin content of 25% and a thickness of 0.124 mm was used. For the other full length bias layers 4 to 7, a product number “MR350C-175S” having a fiber tensile modulus of 30 t / mm ² , a resin content of 25%, and a thickness of 0.145 mm was used.
The two sets of bias set layers A1 and A2 were both 0.290 mm in thickness. Further, the inner straight layer made of the full length layer 1 had a thickness of 0.146 mm, and the straight layer made of the full length layers 2 and 3 had a thickness of 0.248 mm.

(Comparative Example 3)
The bias set layers A1 and A2 were divided and arranged in the inner layer portion I and the outer layer portion II, but no hoop layer was provided.
That is, as shown in FIG. 10, the laminated structure of the prepreg is such that an inner bias set layer A1 having a fiber angle of ± 45 ° is arranged on the full length layers 1 and 2 out of the total length layers 1 to 7, and the total length The layers 3 and 4 are straight layers with a fiber angle of 0 °, the bias layer A2 of the outer layer portion with a fiber angle of ± 45 ° is disposed on the full length layers 5 and 6, and the outermost full length layer 7 is a straight layer with a fiber angle of 0 °. It was.
As the prepreg used, a product number “TR350C-175S” having a fiber tensile elastic modulus of 24 t / mm ² , a resin content of 25%, and a thickness of 0.146 mm was used for the full length straight layer 3. For the other full length layers 4 and 7, a product number “MR350C-150S” having a fiber tensile modulus of 30 t / mm ² , a resin content of 25%, and a thickness of 0.124 mm was used. For the other full length bias layers 1, 2, 5, and 6, a product number “MR350C-175S” having a fiber tensile modulus of elasticity of 30 t / mm ² , a resin content of 25%, and a thickness of 0.145 mm was used.
The two sets of bias set layers A1 and A2 were both 0.290 mm in thickness. Further, the inner straight layer made of the full length layers 3 and 4 had a thickness of 0.270 mm, and the outermost straight layer made of the full length layer 7 had a thickness of 0.124 mm.

(Comparative Example 4)
The bias set layers A1 and A2 were divided and arranged in an inner layer portion I and an outer layer portion II, and the hoop layer B was placed in contact with the inner bias set layer A1.
That is, as shown in FIG. 11, the prepreg laminated structure is arranged with the bias set layer A1 of the inner layer portion having a fiber angle of ± 45 ° in the full length layers 1 and 2 out of the total length layers 1 to 8 in total, A hoop layer B having a fiber angle of 90 ° was arranged on the outer full length layer 3 and the full length layers 4 and 5 were straight layers having a fiber angle of 0 °. The full length layers 6 and 7 formed an outer layer bias set layer A2 with a fiber angle of ± 45 °, and the outermost full length layer 8 was a straight layer with a fiber angle of 0 °.
The prepreg type used for each of the straight layer, the bias set layers A1 and A2, and the hoop layer B was the same as in Example 1.
The two sets of bias set layers A1 and A2 were both 0.290 mm in thickness. Further, the inner straight layer composed of the full length layers 4 and 5 had a thickness of 0.248 mm, and the outermost straight layer composed of the full length layer 8 had a thickness of 0.124 mm.

(Comparative Example 5)
Although the laminated structure of the prepreg was the same as that of Example 2, the fiber angles of the bias set layers A1 and A2 of the inner layer portion and the outer layer portion were both ± 15 ° and were excluded from the orientation angle of the bias layer of the present invention. Other configurations and types of prepreg used were also the same as those in Example 2.

(Comparative Example 6)
Although the laminated structure of the prepreg was the same as that of Example 2, the fiber angles of the bias set layers A1 and A2 of the inner layer portion and the outer layer portion were both set to ± 75 ° and excluded from the orientation angle of the bias layer of the present invention. Other configurations and types of prepreg used were also the same as those in Example 2.

(Comparative Example 7)
The prepreg laminated structure was the same as in Example 2, but the fiber angle of the bias set layer A1 in the inner layer portion was ± 15 °, the fiber angle of the bias set layer A2 in the outer layer portion was ± 75 °, and the fiber angle ratio θ2 / Θ1 was set to 5. Other configurations and types of prepreg used were also the same as those in Example 2.

(Measurement of forward flex)
The forward flex is an index of the hardness on the grip side (hand side) of the shaft, and as shown in FIG. 12, the position 799 mm from the head-side tip 11 is a fulcrum P1, and the grip-side rear end 12 from this fulcrum P1. This position is obtained by measuring the amount of deflection of the head-side tip 11 by suspending a weight W1 of 2.7 kg from the head-side tip 11 at a position 64 mm from the position 140 mm closer to the fixing point P2.

(Torque measurement)
As shown in FIG. 13, the torque (deg) is fixed at a position 40 mm from the head-side tip 11 of the shaft 10, and is 136.3 N · cm (13.9 kgf · cm) at a point 865 mm from the head-side tip 11. ) And the twist angle at that time was measured.

(Measurement of 3-point bending strength)
Three-point bending strength is the breaking strength determined by the Product Safety Association. As shown in FIG. 14, the shaft 10 was supported at three points, a load F was applied from above, and a load value (peak value) when the shaft 10 was broken was measured. The measurement points were 175 mm position (point A), 525 mm position (point B), and 993 mm position (point C) from the head-side tip 11 of the shaft 10. The span of the support point 51 was 300 mm. (The illustration shows an example of A point measurement)

(Measurement of crushing strength)
Using a universal compression tester, test pieces having a length of about 10 mm centered on the 10 mm position, 100 mm position, 200 mm position, and 300 mm position from the grip side rear end 12 of the shaft 10 are subjected to a compression test. Showed power.

As can be seen from Table 1, when Comparative Example 3 in which the bias layer is divided and arranged in the inner layer part I and the outer layer part II is compared with Comparative Examples 1 and 2 in which the bias layer is not divided, the comparative example 3 is more flexible. It was confirmed that the torque could be reduced in a well-balanced manner without increasing it and without reducing the strength.
Furthermore, when Examples 1 and 2 in which the bias layer is divided and the hoop layer B is formed in contact with the bias layer are compared with Comparative Example 3 in which the hoop layer is not provided, Examples 1 and 2 are more It was confirmed that the torque could be reduced and the strength increased without increasing the flex. This is considered due to the fact that the deformation in the twisting direction is effectively suppressed by the cross-sectional deformation suppressing performance of the hoop layer B.

When comparing the first and second embodiments in which the hoop layer B is disposed adjacent to the bias set layer A2 in the outer layer portion and the comparative example 4 in which the hoop layer B is disposed adjacent to the bias set layer A1 in the inner layer portion, the first and second embodiments are compared. It was confirmed that the torque can effectively reduce the torque.
Further, when Example 2 in which the hoop layer B is disposed adjacent to the outer side of the bias set layer A2 in the outer layer portion is compared with Example 1 in which the hoop layer B is disposed adjacent to the inner side, it is found that Example 2 can further reduce the torque. It was.

  When Examples 2 to 6 having different thickness ratios T2 / T1 of the bias set layers A1 and A2 of the inner layer part and the outer layer part are compared, Examples 2, 3, and 6 having a thickness ratio of 1 to 1.4 are compared. Although the result of No. 1 was good, the effect of lowering torque was weakened in Example 4 less than 1, and in Example 5 exceeding 1.4, the flex was increased and the strength was also lowered.

When Examples 7 to 11 and Comparative Examples 5 and 6 having different fiber angles of the bias set layers A1 and A2 are compared, Examples 7 to 11 in the fiber angle range of ± 25 ° to 65 ° show torque, flex, and strength. However, Comparative Examples 5 and 6 having a fiber angle outside the range of ± 25 ° to 65 ° could not effectively reduce the torque.
Furthermore, it was confirmed that when the fiber angle of the bias set layers A1 and A2 was decreased, the strength at the shaft tip side was improved, and when the fiber angle was increased, the strength at the grip side was improved.

  From the result of Comparative Example 7, it was confirmed that when the fiber angle ratio θ2 / θ1 of the bias set layers A1 and A2 of the inner layer portion and the outer layer portion is larger than 2, the flex increases and the torque cannot be reduced.

1 is a schematic view of a golf club shaft according to a first embodiment of the present invention. It is a figure which shows the laminated structure of the prepreg of the golf club shaft shown in FIG. It is the BB sectional view taken on the line of FIG. It is a figure which shows the prepreg laminated structure of 2nd Embodiment. It is a figure which shows the prepreg laminated structure of 3rd Embodiment. It is a figure which shows the prepreg laminated structure of 4th Embodiment. 6 is a view showing a prepreg laminated configuration of Example 12. FIG. 3 is a view showing a prepreg laminated configuration of Comparative Example 1. FIG. 5 is a view showing a prepreg laminated configuration of Comparative Example 2. FIG. 6 is a view showing a prepreg laminated configuration of Comparative Example 3. FIG. 6 is a view showing a prepreg laminated structure of Comparative Example 4. FIG. It is a figure which shows the measuring method of a forward type flex. It is a figure which shows the measuring method of a torque. It is a figure which shows the measuring method of three-point bending strength.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Shaft 21-35 Fiber reinforced prepreg 41-49 Full length layer A1 Inner bias set layer A2 Outer bias set layer B Hoop layer C Outermost full length straight layer I Inner layer part II Outer layer part III Middle layer part 1-8 Full length layer in a table | surface

Claims (5)

A golf club shaft made of a prepreg laminate,
Comprising at least six full-length layers consisting of the prepregs arranged over the entire length of the shaft,
As the full length layer, the orientation angle θ ° with respect to the shaft axis of the reinforcing fiber is in the range of ± 25 ° or more and ± 65 ° or less, and one bias layer in which the orientation angle is + θ ° and one layer that is −θ °. And at least two bias set layers that are laminated as inner and outer bias layers so that the reinforcing fibers cross each other.
If the half of the inner circumferential side of the shaft is divided into the inner layer portion and the outer half of the shaft outer circumferential portion is divided into the outer layer portion, the outer bias layer of at least one pair of the bias set layers is arranged in the outer layer portion. On the other hand, the inner bias layer of at least one other bias set layer is disposed in the inner layer portion,
Further, a hoop layer whose orientation angle with respect to the shaft axis of the reinforcing fiber is within a range of ± 80 ° or more and 90 ° or less is disposed in contact with the bias layer of the outer layer portion, and
The outermost full length layer of the outer layer portion is a golf club shaft characterized in that the orientation angle of the reinforcing fiber with respect to the shaft axis is in the range of 0 ° to ± 10 °. The weight of the shaft is 50 g or more and 70 g or less,
^2. The golf club shaft according to claim 1, wherein the prepreg used in the hoop layer has a tensile elastic modulus of reinforcing fiber of 30 t / mm ² or more and 80 t / mm ² or less and a resin content of 30% or more and 40% or less. .   When the orientation angle of the reinforcing fiber of the bias set layer of the inner layer portion is ± θ1 ° and the orientation angle of the reinforcing fiber of the bias set layer of the outer layer portion is ± θ2 °, θ2 / θ1 is in the range of 1 to 2 The golf club shaft according to claim 1 or claim 2.   The ratio T2 / T1 between the total thickness T1 of the bias set layer in the inner layer portion and the total thickness T2 of the bias set layer in the outer layer portion is 1 or more and 1.4 or less. The golf club shaft according to claim 1.   The total number of the full length layers is an odd number, an intermediate layer is an intermediate layer portion, and a straight layer in which an orientation angle with respect to the shaft axis of the reinforcing fiber is within a range of 0 ° to ± 10 ° is disposed as the intermediate layer portion. The golf club shaft according to any one of claims 1 to 4, wherein the golf club shaft is provided.

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