JPH10192464A - Shaft and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shaft having a sufficient torsional strength while ensuring constant torsional rigidity, bending rigidity and bending strength without increasing the weight, and a method of manufacturing such a shaft. SOLUTION: This shaft has an bias layer 1 250μm or less thick containing a fiber reinforced resin composite material reinforced by a reinforcing fiber having a reinforcing direction oblique to the shaft axial direction, an intermediate layer 2 150μm or less thick containing a fiber reinforce resin composite material reinforced by a reinforcing fiber having a reinforcing direction oblique by at least 30 deg. to the shaft axial direction, and a reinforcing directional bending strength higher than the reinforcing fiber of the bias layer 1, and a 0 layer 3 270μm or less thick containing a fiber reinforced composite material reinforced by a reinforcing fiber having a reinforcing direction laid along the shaft axial direction and a reinforcing directional bending rigidity lower than the reinforcing fiber of the intermediate layer 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lightweight and high-performance shaft for use in golf clubs, fishing rods, and the like, and a method for manufacturing the same.

[0002]

2. Description of the Related Art A golf club shaft made of a fiber-reinforced resin composite material generally has a direction along the axial direction of the golf club shaft (it does not need to coincide with the axial direction. (A direction that does not differ from the axial direction of the golf club shaft) and an oblique layer in which the reinforcing direction of the reinforcing fibers is oblique to the axial direction of the golf club shaft. Some have a layer in which the fibers are arranged in the circumferential direction of the golf club shaft. In a golf club shaft made of a fiber-reinforced resin composite material, the 0-degree layer mainly controls the bending characteristics of the shaft, and the oblique layer mainly controls the torsional characteristics of the shaft.

In general, in golf clubs, it is desired to reduce the weight of a golf club shaft in order to improve the flight distance of a ball. A golf club shaft made of a fiber-reinforced resin composite material is also required to be further reduced in weight, and it is general to reduce the weight mainly by reducing the thickness of the golf club shaft.

[0004] However, the torsional strength of a golf club shaft depends on a so-called oblique layer in which reinforcing fibers are obliquely formed in the axial direction of the shaft. Therefore, simply reducing the wall thickness may cause an excessive torsional force to act on the golf club shaft when the hitting position of the ball deviates significantly from the sweet spot of the golf club, thereby causing a risk of torsion breaking. There was a fear.

[0005] In carbon fiber reinforced composite materials generally used for golf club shafts, the bending stiffness tends to decrease as the bending strength increases, and the bending strength tends to decrease as the bending stiffness increases. When a material having high bending strength is used for a lightweight golf club shaft for the purpose of preventing torsional breakage, it may be difficult to secure the torsional rigidity required for a golf club. On the other hand, when the torsional stiffness of the golf club shaft is increased, the amount of rotation of the golf club head in the axial direction at impact is reduced, and the flying direction of the ball is stabilized. Is more advantageous,
Since the bending strength of the material used for the oblique layer is reduced, a problem may occur that the torsional strength of the golf club shaft itself is reduced.

As described above, in the conventional golf club shaft made of the fiber-reinforced resin composite material, it is difficult to secure a sufficient torsional strength while securing a constant torsional rigidity required for the golf club shaft. . This problem is particularly prominent in a thin golf club shaft, which has been a factor that hinders the weight reduction of the golf club shaft.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a shaft used for a lightweight golf club, a fishing rod, etc., while maintaining a constant torsional rigidity, bending rigidity and bending strength without increasing weight. An object of the present invention is to provide a shaft having a sufficient torsional strength and a method for manufacturing such a shaft.

[0008]

In order to achieve the above object, a shaft according to the present invention has a thickness including a fiber-reinforced resin composite material reinforced by reinforcing fibers whose reinforcing direction is oblique to an axial direction of the shaft. An oblique layer of 250 μm or less, and a reinforcing direction formed outside the oblique layer, the reinforcing direction of which is at least 30 degrees oblique to the axial direction of the shaft, and the bending strength in the reinforcing direction is higher than the reinforcing fibers of the oblique layer. An intermediate layer having a thickness of 150 μm or less including a fiber-reinforced resin composite material reinforced by a reinforcing fiber, and a reinforcing direction formed outside the intermediate layer along a shaft axis direction and a reinforcing direction higher than the reinforcing fibers of the intermediate layer. And a zero-degree layer having a thickness of 270 μm or less including a fiber-reinforced resin composite material reinforced by a reinforcing fiber having low bending rigidity.

In a preferred aspect of the present invention, the oblique layer comprises at least two layers having a thickness of 70 μm or less containing a fiber-reinforced resin composite material.

[0010] A preferred embodiment of the present invention is characterized in that the shaft weight is 40 g or less per 1 m of length.

In a preferred aspect of the present invention, the oblique layer includes a fiber-reinforced resin composite material having a bending elastic modulus in a fiber reinforcing direction of 200 GPa or more.

In a preferred aspect of the present invention, the 0-degree layer contains a fiber-reinforced resin composite material using carbon fibers or metal fibers as reinforcing fibers. .

[0013] Further, according to the method of manufacturing a shaft of the present invention, the mandrel preferably includes a fiber reinforced resin composite material reinforced by a reinforcing fiber whose reinforcing direction is oblique to the axial direction of the mandrel. A cross layer is formed, and the reinforcing direction is at least 30 degrees oblique to the axial direction of the mandrel and the bending strength in the reinforcing direction is higher than the reinforcing fiber of the cross layer. Forming an intermediate layer having a thickness of 150 μm or less containing a reinforced fiber reinforced resin composite material, and bending outside the intermediate layer along the axial direction of the mandrel in a reinforcing direction more than the reinforcing fibers of the intermediate layer. It is characterized in that a 0-degree layer having a thickness of 270 μm or less including a fiber-reinforced resin composite material reinforced by reinforcing fibers having low rigidity is formed.

According to a preferred aspect of the present invention, at least one of the oblique layer, the intermediate layer, and the zero-degree layer is formed by any one of a sheet winding method, a filament winding method, and a tape winding method. It is characterized by being formed by the above.

The reinforcing fiber used in the present invention is not limited as long as it is a fiber such as glass fiber, aramid fiber, carbon fiber, and metal fiber. However, as a molded product, carbon fiber having excellent mechanical properties is used. It is desirable to use fibers. As the carbon fibers, polyacrylonitrile-based or pitch-based carbon fibers can be used.

The form of the reinforcing fibers may be a unidirectional material aligned in one direction or a woven material. The ratio of the number of weft lines of the woven material and the angle formed by the weft lines are particularly important. It is not limited. In the case where a woven material is used, the direction of reinforcement in which the number of fibers is large among the meridians and wefts is determined as the main reinforcement direction.

Further, the matrix resin of the fiber-reinforced resin composite material used in the present invention is not limited as long as it is used for a general fiber-reinforced resin composite material. Specifically, an epoxy resin or the like can be used, but a single resin material or a combination of two or more resin materials can be used as the matrix resin.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. As shown in FIG. 1, the shaft of the present embodiment is a shaft made of a reinforcing fiber and a matrix resin, and is a fiber-reinforced resin composite material reinforced by a reinforcing fiber whose reinforcing direction is oblique to the axial direction of the shaft. An oblique layer 1 having a thickness of 250 μm or less and a reinforcing layer formed outside the oblique layer 1, the reinforcing direction of which is oblique at least 30 degrees with respect to the axial direction of the shaft.
Thickness 150 including a fiber reinforced resin composite material reinforced by a reinforcing fiber having a higher bending strength in the reinforcing direction than the reinforcing fiber
an intermediate layer 2 having a thickness of not more than μm,
A fiber having a thickness of 270 μm or less including a fiber-reinforced resin composite material reinforced by a reinforcing fiber whose bending direction is lower in the reinforcing direction than the reinforcing fiber of the intermediate layer 2 along the shaft axis direction.
And a third layer.

In the present embodiment, since the intermediate layer 2 is disposed mainly for the purpose of improving the torsional strength, the use of a material having a higher bending strength than that of the oblique layer 1 is used for improving the torsional strength. It is preferred in that respect. Usually, the bending strength required for the material used as the intermediate layer 2 is sufficient as long as it is equal to or higher than the bending strength of the material used for the oblique layer 1, but preferably, it is used for the oblique layer 1. Desirably, it is at least 10% higher than the bending strength of the material.

The material used for the intermediate layer 2 is 0
It is preferable to use a material having a higher bending rigidity than the material used for the outer layer 3 from the viewpoint of maintaining the bending rigidity required for the shaft. Usually, the bending stiffness required for the material used for the intermediate layer 2 is sufficient as long as it is equal to or greater than the bending stiffness of the material used for the 0-degree layer 3. Since they are arranged obliquely at 30 degrees, it is desirable that the bending rigidity of the material used for the 0-degree layer 3 is at least 20% higher than that of the material used for the layers.
Generally, the orientation angle of the intermediate layer 2 is used in the range of 30 degrees to 45 degrees. As the orientation angle of the intermediate layer 2 increases, it is desirable to use a material having a large bending rigidity for the intermediate layer 2. .

The material used for the intermediate layer 2 has a thickness of 150 μm or less so as not to cause a significant increase in the weight of the shaft, but is extremely thin compared to the thickness of the shaft. In such a case, the improvement of the torsional strength by inserting the intermediate layer 2 cannot be expected, which is not preferable. In the shaft made of the fiber-reinforced resin composite material of this embodiment, since the thickness of the 0-degree layer 3 is 270 μm or less and the thickness of the oblique layer 1 is 250 μm or less, the thickness of the intermediate layer 2 is 60 μm. １５０150 μm is desirable.

The material used for the intermediate layer 2 needs to have the reinforcing fibers reinforced diagonally at least 30 degrees with respect to the axial direction of the shaft. Below this range, the bending rigidity, bending strength and torsional rigidity of the shaft are hardly impaired, but the torsional strength is somewhat inferior.
On the other hand, if the reinforcing direction of the reinforcing fibers is in the range of 30 to 90 degrees with respect to the axial direction of the shaft, it is desired to improve the torsional strength by disposing the intermediate layer 2.

The material used for the intermediate layer 2 is such that the stress generated in the intermediate layer 2 when the shaft is twisted with a predetermined force is less than the allowable stress of the reinforcing fibers used for the intermediate layer 2. In addition, the rigidity and thickness of the intermediate layer 2 and the reinforcing direction of the reinforcing fibers are determined so that the stress generated in the oblique layer 1 is equal to or less than the allowable stress of the reinforcing fibers used in the oblique layer 1. Good.

The present invention has a great effect on a lightweight golf club shaft having a shaft weight of 45 g or less per meter in length. In the lightweight golf club shaft as described above, since the fiber reinforced resin composite material that can be used for the 0-degree layer and the oblique layer is reduced, it is necessary to adjust the intermediate strength to optimize both the torsional rigidity and the torsional strength. The role of layers becomes important.

The present invention has a great effect in a golf club shaft using a carbon fiber reinforced resin composite material having a bending elastic modulus in the fiber reinforcement direction of 200 GPa or more in the oblique layer. As described above, in a carbon fiber reinforced resin composite material generally used for a golf club shaft, since the bending strength tends to decrease with an increase in bending stiffness, the bending elastic modulus is 200 GPa or more. In the golf club shaft using the carbon fiber reinforced composite material having a low ratio in the oblique layer, the bending strength of the oblique layer is reduced, so that when the torque is applied to both ends of the golf club shaft by applying a torque of 300 Nm or more, the twist is performed. Torsional failure may occur in the oblique layer. The bending elastic modulus in the fiber reinforcement direction of the oblique layer is 200 GPa
The role of the intermediate layer is important for improving the torsional strength of the golf club shaft using the above carbon fiber reinforced resin composite material and preventing torsional breakage. In addition,
In a preferred embodiment, the oblique layer is formed by stacking two or more layers having a thickness of 70 μm or less.

The cross layer is provided to impart torsional characteristics (torsional rigidity, torsional strength) of the shaft. In the present invention, not only the cross layer is provided but also a certain torsion layer. In order to secure both rigidity and torsional strength, the bending strength is higher than that of the
The intermediate layer having a higher bending rigidity than the first layer and having a thickness of 150 μm or less and being oblique at least 30 degrees is laminated.

In order to manufacture a shaft made of the fiber reinforced resin composite material of the present invention, a prepreg is wound around a mandrel having the same taper as the conventionally known shaft inside diameter from the innermost layer to the outermost layer in order. , Wrapping tee
A method of winding and forming a sheet (sheet winding method), a filament winding method, a tape winding method, and the like can be used.

[0028]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist. The measurement of tensile elastic modulus and tensile strength of the carbon fiber described below is based on JIS-R7
The value obtained according to the method shown in JIS-K7071 is used for the measurement of each property of the prepreg.

As an oblique layer of the shaft, a carbon fiber A manufactured by Toray Industries, Inc. (tensile elastic modulus in the reinforcing fiber direction: 476 GP)
a, a unidirectional prepreg A obtained by impregnating epoxy resin into a sheet in which tensile strength in the reinforcing fiber direction: 3920 MPa) is arranged in parallel and in a sheet form. The prepreg A has a matrix resin content of 27% by weight. Bending rigidity of prepreg A in the reinforcing fiber direction is 240G
Pa, the bending strength in the reinforcing fiber direction was 1270 MPa, and the thickness was 52 μm.

As the intermediate layer of the shaft, carbon fiber B manufactured by Toray Industries, Inc. (tensile elastic modulus in the reinforcing fiber direction: 378 GP)
a, a unidirectional prepreg B obtained by impregnating epoxy resin into a sheet in which the tensile strength in the reinforcing fiber direction: 4410 MPa) is arranged in parallel and in a sheet form. The matrix resin content of this prepreg B is 37% by weight. Bending rigidity of prepreg B in the direction of reinforcing fiber is 195G
Pa, the bending strength in the reinforcing fiber direction was 1520 MPa, and the thickness was 48 μm.

As the 0-degree layer of the shaft, carbon fiber C manufactured by Toray Industries, Inc. (tensile elastic modulus in the direction of the reinforcing fiber: 230 GP)
a, a unidirectional prepreg C obtained by impregnating epoxy resin into a sheet in which tensile strength in the reinforcing fiber direction: 4900 MPa) is arranged in parallel and in a sheet form. The matrix resin content of this prepreg C is 30% by weight. Bending rigidity of prepreg C in the reinforcing fiber direction is 120G
Pa, the bending strength in the reinforcing fiber direction was 1670 MPa, and the thickness was 123 μm.

Example 1 As shown in FIG. 2, an oblique layer 1 was placed on a release-treated stainless steel mandrel having a tip outer diameter of 6.5 mm, a taper of 6.0 / 1000, and a length of 1100 mm. The prepreg A is wound for a total of two turns so that the fiber direction is +40 degrees and -40 degrees with respect to the core metal axis direction, and the prepreg B is formed as an intermediate layer around the prepreg B with the fiber direction relative to the core metal axis direction. Wrap a total of 2 turns so that it becomes +45 degrees and -45 degrees, and further outside, prepreg C as 0 degree layer
Was wound for a total of two turns so that the fiber direction coincided with the mandrel axis. Thereafter, methods known to those skilled in the art include wrapping tape winding, heat curing in a curing oven,
The lapping tape was removed and the outer periphery was polished to obtain a shaft.

With respect to this shaft, the torque when the shaft was broken was 54 Nm, and the torsion angle at that time was 1
It was 2.6 degrees. Therefore, when the torsional strength generally used for a golf club shaft was obtained by the following equation (1), it was 680 Nm.

Golf club torsional strength (Nm degrees) = torque at break (Nm) × torsional angle at break (degrees) (1) The shaft weight was 38 g.

Example 2 As in Example 1, prepreg A was wound as an oblique layer for a total of two turns so that the fiber direction was +40 degrees and −40 degrees with respect to the axial direction of the cored bar. As the intermediate layer, the prepreg B has a fiber direction of +35 degrees with respect to the core metal axis direction,
In addition, wrapping was performed for a total of two turns so as to form a 0-degree layer around the prepreg C so that the fiber direction coincided with the mandrel axis. Thereafter, molding was performed in the same manner as in Example 1 to obtain a shaft.

With respect to this shaft, the torque at break was 50 Nm, and the torsion angle at that time was 12.9.
Degree. Therefore, the torsional strength using the equation (1) in the same manner as in Example 1 was 645 Nm.
The shaft weight was 38 g.

Comparative Example 1 In the same manner as in Example 1, prepreg A was wound as an oblique layer for a total of two turns so that the fiber direction was +40 degrees and −40 degrees with respect to the core metal axis direction. Prepreg C was wound as a 0-degree layer for a total of two turns so that the fiber direction coincided with the mandrel axis. Thereafter, molding was performed in the same manner as in Example 1 to obtain a shaft.

With respect to this shaft, the torque at break was 38 Nm, and the torsion angle at that time was 15.6 degrees. Therefore, the torsional strength using the equation (1) in the same manner as in Example 1 was 592 Nm. The shaft weight was 34 g.

Comparative Example 2 In the same manner as in Example 1, prepreg A was wound as an oblique layer for a total of two turns so that the fiber direction was +40 degrees and −40 degrees with respect to the axial direction of the cored bar. As the intermediate layer, the prepreg B has a fiber direction of +25 degrees with respect to the core metal axis direction,
And -25 degrees, and a prepreg C was further wound on the outer side as a 0-degree layer for a total of two turns so that the fiber direction coincided with the mandrel axis. Thereafter, molding was performed in the same manner as in Example 1 to obtain a shaft.

With respect to this shaft, the torque at break was 40 Nm, and the torsion angle at that time was 14.0 degrees. Therefore, the torsional strength using equation (1) in the same manner as in Example 1 was 560 Nm. The shaft weight was 38 g.

Comparative Example 3 In the same manner as in Example 1, prepreg A was wound as an oblique layer for a total of two turns so that the fiber direction was +40 degrees and −40 degrees with respect to the core metal axis direction, and was wrapped around the outside. As an intermediate layer, the prepreg A has a fiber direction of +45 degrees with respect to the core metal axis direction,
And a wrap around the prepreg C as a 0-degree layer for a total of two wraps so that the fiber direction coincides with the mandrel axis. Thereafter, molding was performed in the same manner as in Example 1 to obtain a shaft.

With respect to this shaft, the torque at break was 42 Nm, and the torsion angle at that time was 11.8 degrees. Therefore, the torsional strength using equation (1) in the same manner as in Example 1 was 496 Nm. The shaft weight was 38 g.

Comparative Example 4 In the same manner as in Example 1, prepreg A was wound as an oblique layer for a total of two turns so that the fiber direction was +40 degrees and −40 degrees with respect to the core metal axis direction. As an intermediate layer, the prepreg C has a fiber direction of +45 degrees with respect to the core metal axis direction,
And a wrap around the prepreg C as a 0-degree layer for a total of two wraps so that the fiber direction coincides with the mandrel axis. Thereafter, molding was performed in the same manner as in Example 1 to obtain a shaft.

With respect to this shaft, the torque at break was 22 Nm, and the torsion angle at that time was 15.1 degrees. Therefore, the torsional strength using equation (1) in the same manner as in Example 1 was 332 Nm. The shaft weight was 37 g.

The following table summarizes the above results.

[0046]

[Table 1]

[0047]

According to the golf club shaft of the present invention, since a material having higher strength and a thinner thickness than that of the oblique layer is disposed on the oblique layer as an intermediate layer, the torsional breakage can be achieved without substantially changing the torsion angle and the shaft weight. Can be prevented. Furthermore, since the shaft itself is lightweight, it can be used for a lightweight golf club that requires an increased flight distance.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a shaft according to the present invention.

FIG. 2 is an explanatory view showing a method of winding a prepreg on a shaft in the present invention.

[Explanation of symbols]

 1: Oblique layer 2: Middle layer 3: 0 degree layer

Claims (7)

[Claims] 1. An oblique layer having a thickness of 250 μm or less containing a fiber-reinforced resin composite material reinforced by a reinforcing fiber whose oblique direction is oblique to the shaft axis direction, and formed outside the oblique layer. A thickness of 150 μm or less including a fiber-reinforced resin composite material reinforced by a reinforcing fiber whose reinforcing direction is oblique at least 30 degrees with respect to the axial direction of the shaft and whose bending strength in the reinforcing direction is higher than that of the reinforcing fibers of the oblique layer. An intermediate layer, and a fiber-reinforced resin composite material formed outside the intermediate layer and reinforced by a reinforcing fiber whose reinforcing direction is along the shaft axis direction and has lower bending rigidity in the reinforcing direction than the reinforcing fibers of the intermediate layer. A shaft comprising: a 0-degree layer having a thickness of 270 μm or less. 2. The shaft according to claim 1, wherein the oblique layer comprises at least two or more layers containing a fiber-reinforced resin composite material and having a thickness of 70 μm or less. 3. The shaft according to claim 1, wherein the weight of the shaft is 40 g or less per 1 m of length. 4. The shaft according to claim 1, wherein the oblique layer includes a fiber-reinforced resin composite material having a bending elastic modulus in a fiber reinforcement direction of 200 GPa or more. 5. The shaft according to claim 1, wherein said 0-degree layer contains a fiber-reinforced resin composite material using carbon fibers or metal fibers as reinforcing fibers. 6. An oblique layer having a thickness of 250 μm or less including a fiber-reinforced resin composite material reinforced by a reinforcing fiber whose reinforcing direction is oblique to an axial direction of the mandrel is formed on the mandrel. Outside the layer, a fiber reinforced resin composite material reinforced by a reinforcing fiber whose reinforcing direction is oblique at least 30 degrees with respect to the axial direction of the mandrel and has a higher bending strength in the reinforcing direction than the reinforcing fibers of the oblique layer. Including thickness 150
μm or less of an intermediate layer, a fiber reinforced resin reinforced by a reinforcing fiber whose bending direction is lower than the reinforcing fiber of the intermediate layer along the axial direction of the mandrel outside the intermediate layer. A method for manufacturing a shaft, comprising forming a 0-degree layer having a thickness of 270 μm or less containing a composite material. 7. The method according to claim 1, wherein at least one of the oblique layer, the intermediate layer and the 0-degree layer is formed by any one of a sheet winding method, a filament winding method and a tape winding method. Claim 6
3. The method for producing a shaft according to 1.