JP2011212463A - Golf club shaft and golf club using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a golf club shaft including a torsional rigidity-retaining layer formed of a prepreg having high isotropy and securing sufficient torsional rigidity with the smaller number of plies of the smaller number of prepregs, and to obtain a golf club using it.SOLUTION: The golf club shaft includes the torsional rigidity-retaining layer formed of a thermosetting resin having reinforced fiber obliquely intersecting a longitudinal direction of a shaft. The torsional rigidity-retaining layer includes a prepreg set of a plurality of layers formed of the set of prepregs of three or more layers which are composed by impregnating the reinforced fiber with the thermosetting resin. At least the three layers of the prepreg in the prepreg set of the plurality of layers contain the reinforced fiber arranged in mutually different directions. The prepreg set of the plurality of layers is continually wound two or more times by stacking at least three layers of the prepregs.

Description

  The present invention relates to a golf club shaft (carbon shaft) and a golf club manufactured by winding and thermosetting a thermosetting resin prepreg (sheet).

  A prepreg is known as a sheet-like material obtained by impregnating reinforcing fibers (reinforcing fibers, carbon fibers, etc.) with an uncured thermosetting resin. In a golf club shaft, a plurality of prepregs are arranged on a mandrel having a tapered shaft. Is wound and heat-cured to form a tapered shaft.

  FIG. 10 is a conceptual diagram illustrating a typical configuration example of the golf club shaft 1 including a plurality of prepregs. The golf club shaft 1 is composed of a prepreg (90 ° (hoop) layer prepreg) having a fiber direction orthogonal to the longitudinal direction of the shaft in order from the lower layer, a compression rigidity (collapse rigidity) holding layer 2, and a fiber direction. Torsional rigidity holding layer 3 composed of a prepreg (an oblique (bias) prepreg, 45 ° layer prepreg) that is oblique to the longitudinal direction of the shaft, and a prepreg in which the fiber direction is parallel to the longitudinal direction of the shaft It has a bending rigidity holding layer 4 composed of (0 ° layer prepreg). The compression rigidity holding layer 2 and the torsional rigidity holding layer 3 may be interchanged. Since the prepreg constituting the compression rigidity holding layer 2 and the bending rigidity holding layer 4 has a single fiber direction, it is generally called a UD (UNI-DIRECTION) prepreg. Further, the torsional rigidity retaining layer 3 generally includes a pair of UD prepregs (45 ° layer, bias layer) whose fiber directions are symmetrical with respect to the longitudinal direction of the shaft (generally ± 45 ° with respect to the longitudinal direction). Plain woven fabric (biaxial woven fabric), triaxial woven fabric, plain woven fabric (biaxial woven fabric) prepreg impregnated with thermosetting resin, triaxial woven fabric prepreg, and twisted rigid retaining layer 3 The golf club shaft 1 included in the above has also been developed by the present applicant.

JP-A-9-131422 JP 2000-51413 A

  In such a golf club shaft 1, the fiber direction of the compression stiffness retaining layer 2 is limited to 90 °, and the fiber stiffness of the bending stiffness retaining layer 4 is limited to 0 °. On the other hand, the torsional rigidity retaining layer 3 has higher isotropicity (torsional strength regardless of direction) as the directions of the fibers contained therein are more diverse, and a feel close to that of a steel shaft can be obtained. It is believed that. This is the main reason why a plain woven fabric, a triaxial woven fabric, and a tetraaxial woven fabric are used for the torsional rigidity retaining layer 3. If the concept of “isotropic degree (frequency)” is used for the isotropic magnitude, the isotropic degree is in the order of a pair of bias layer prepreg, plain woven fabric prepreg, triaxial woven fabric layer prepreg, and tetraaxial woven fabric layer prepreg. It is thought to rise. Incidentally, the steel shaft has the highest degree of isotropicity.

  However, another problem is that the thickness (weight) of the torsional rigidity retaining layer 3 is limited. As long as the thickness is limited, a device for securing sufficient torsional rigidity with a smaller number of plies (number of windings) of a smaller prepreg is necessary. In other words, there is a need for a structure that can provide higher torsional rigidity when the same number of different or similar prepregs are used.

  The present invention has been made on the basis of the above-mentioned problem awareness, and the prepreg constituting the torsional rigidity retaining layer is highly isotropic, and can secure sufficient torsional rigidity with a smaller number of plies of fewer prepregs. An object is to obtain a club shaft and a golf club using the same.

  In the present invention, the conventional torsional rigidity retaining layer is formed by first winding a specific prepreg in which the oblique direction of the fiber with respect to the longitudinal direction of the golf club shaft is wound, and then winding a prepreg in another fiber direction thereon. If the prepregs with different fiber directions are overlapped in advance, and the prepregs are wound twice or more continuously in a state where they are stacked, when the stacked prepregs are viewed as one prepreg, etc. On the other hand, when each prepreg is viewed as one prepreg, prepregs in different fiber directions are positioned on the front and back of the prepreg over two rotations (circumferences). This is based on the viewpoint that it is possible to suppress misalignment between the layers (displacement between the fibers of each prepreg after heat curing), and thus to increase the torsional rigidity.

That is, the golf club shaft of the present invention is a golf club shaft having a thermosetting resin torsional rigidity holding layer provided with reinforcing fibers oblique to the longitudinal direction of the shaft. A multi-layer set prepreg in which at least three layers of prepregs impregnated with a thermosetting resin are included, and at least three prepregs in the multi-layer set prepreg include reinforcing fibers in different directions The multi-layer set prepreg is characterized in that it is wound twice or more continuously in a state where the prepreg of at least three layers is overlapped.
In the present specification, the “reinforcing fiber” means various fibers such as an alumina fiber, an aramid fiber, a Tyranno fiber, an amorphous fiber, and a glass fiber in addition to the carbon fiber.

  In the multi-layer set prepreg, three layers of UD prepregs obtained by impregnating a reinforcing fiber having a fiber direction aligned in one direction with a thermosetting resin can be included.

  Two of the three UD prepregs can be a pair of inclined UD prepregs whose fiber directions are symmetrical with respect to the longitudinal direction of the shaft.

  The remaining one of the three layers of UD prepregs may be a UD prepreg whose fiber direction is orthogonal to the longitudinal direction of the shaft.

  Alternatively, the remaining one of the three UD prepregs may be a UD prepreg whose fiber direction is parallel to the shaft longitudinal direction.

  The golf club of the present invention is a golf club in which a club head and a grip are mounted on the golf club shaft having the above configuration.

  According to the present invention, the prepreg constituting the torsional rigidity retaining layer is highly isotropic, and a golf club shaft capable of ensuring sufficient torsional rigidity with a smaller number of plies of a smaller number of prepregs and a golf club using the same are obtained. be able to.

1 is a schematic cross-sectional view orthogonal to a longitudinal direction, showing a first embodiment of a golf club shaft according to the present invention. It is a top view of a triaxial fabric. It is sectional drawing which follows the III-III line of FIG. It is a notional plan view of a UD prepreg composed of two UD prepregs in which the direction of reinforcing fibers is symmetrical with respect to the longitudinal direction of the shaft. It is a cross-sectional schematic diagram which shows 2nd Embodiment of the golf club shaft by this invention and orthogonal to a longitudinal direction. It is a cross-sectional schematic diagram which shows 3rd Embodiment of the golf club shaft by this invention and orthogonal to a longitudinal direction. It is a top view of a plain woven fabric. It is sectional drawing of a plain woven fabric. It is a top view of a 4-axis fabric. It is a model perspective view which shows the structural example of the conventional general golf club shaft.

  Embodiments of a golf club shaft according to the present invention will be described below with reference to the drawings. In the present specification, “isotropic” means torsional strength regardless of the direction of the golf club shaft.

(Embodiment 1)
FIG. 1 is a schematic cross-sectional view of a golf club shaft 10 according to a first embodiment of the present invention. As is well known, the golf club shaft 10 is formed in a tapered cylindrical shape having an outer diameter that gradually increases from the small diameter side toward the large diameter side, and a club head is attached to the small diameter side end. A grip is attached to the end portion on the large diameter side, but illustration thereof is omitted.

  Similar to the conventional product of FIG. 10, this golf club shaft 10 includes, in order from the lower layer (inner side), a compression rigidity (collapse rigidity) holding layer 11, a torsion rigidity holding layer 20, a bending rigidity holding layer 12, and a decorative layer (polishing layer). , Bending rigidity holding layer) 13. In FIG. 1, the thicknesses and steps of these layers 11, 20, 12, and 13 are exaggerated for easy understanding of the present embodiment. In FIG. 1, the layers 11, 20, 12, and 13 are drawn so that there is a gap in the vicinity of the winding start end position, but this gap is filled with a thermosetting resin during heat curing. Further, the feature of the present embodiment is the configuration of the torsional rigidity holding layer 20, and the compression rigidity holding layer 11 and the bending rigidity holding layer 12 have the same structure as that of the conventional product in FIG. Therefore, the cross-sectional shape is omitted. In general, the compressive rigidity retaining layer 11 is composed of a 90 ° UD prepreg whose fiber direction is oriented in a direction perpendicular to the longitudinal direction of the shaft, and the bending rigidity retaining layer 12 is formed such that the fiber direction is the longitudinal direction of the shaft. It consists of a 0 ° UD prepreg in parallel. The number of plies of the prepregs of the compression rigidity holding layer 11 and the bending rigidity holding layer 12 is set according to the specifications required for the shaft in consideration of the properties of the reinforcing fibers contained and the properties of the thermosetting resin to be impregnated. . A decorative layer (polishing layer, bending stiffness retaining layer) 13 positioned at the outermost layer of the golf club shaft 10 is composed of a UD prepreg having a 0 ° layer whose fiber direction is parallel to the longitudinal direction of the shaft. By polishing the shaft, the bending rigidity of the shaft is adjusted, and the appearance of the shaft is improved. The compression rigidity holding layer 11, the torsional rigidity holding layer 20, the bending rigidity holding layer 12, and the decorative layer 13 of the present embodiment are all full length layers over the entire length of the golf club shaft 10. A short prepreg may be wound around the small diameter portion at the tip and / or the large diameter portion at hand as necessary (according to a conventional method).

  The torsional rigidity retaining layer 20 is formed by continuously winding a multi-layer set prepreg 30 in which a triaxial woven prepreg 31 and a UD prepreg 32 are overlapped twice. That is, the triaxial woven prepreg 31 and the UD prepreg 32 are preliminarily overlapped to form a multi-layer set prepreg 30 and wound on the compression rigidity holding layer 11 wound on a conical mandrel. A prepreg of the bending rigidity holding layer 12 is wound on the multi-layer set prepreg 30 and is heat-cured according to a conventional method to form the golf club shaft 10. As is well known, the prepregs of the compression rigidity holding layer 11 and the bending rigidity holding layer 12, the triaxial woven prepreg 31 and the UD prepreg 32 have a flat trapezoidal shape so that the total length becomes an integer ply when wound on a mandrel. It is common.

  2 and 3 are conceptual diagrams of the triaxial fabric 3 included in the triaxial fabric prepreg 31. FIG. The triaxial woven fabric 3 has a first warp 3b and a second warp 3c obliquely intersecting with the weft 3a, and these wefts 3a, warps 3b and 3c form a regular hexagonal gap 3P. The structure is woven alternately through the top and bottom of the yarn. The angle θ formed by each yarn is ideally 120 °. Since the triaxial woven fabric has pseudo-isotropic properties, it is less likely to be deformed or displaced by itself than the UD prepreg. Further, when winding the triaxial woven prepreg 31, for example, the weft 3a can be wound in the longitudinal direction of the shaft or orthogonally, but even if there is a deviation in the direction, the length of the shaft is always Reinforcing fibers inclined with respect to the direction will be included.

  As shown in FIG. 4, the UD prepreg 32 includes two inclined UD prepregs 32 a and 32 b in which the direction of the reinforcing fiber is symmetric with respect to the longitudinal direction of the shaft. The inclination direction of the reinforcing fibers contained in the inclined UD prepregs 32a and 32b with respect to the longitudinal direction of the shaft is generally 30 ° to 60 °, but is not limited thereto.

  Here, when only the triaxial woven fabric prepreg 31 is wound a plurality of times, the triaxial woven fabric prepregs come into contact with each other, but the triaxial woven fabric prepreg is formed by weaving yarns in three directions and has unevenness. Therefore, a gap is easily generated between the layers. On the other hand, as in this embodiment, when the triaxial woven prepreg 31 and the UD prepreg 32 are laminated to form a multi-layer set prepreg 30, unevenness generated between the layers is reduced, and thus the thermosetting resin of the prepreg is cured. In some cases, the displacement between the layers of the triaxial woven prepreg 31 and the UD prepreg 32 (deviation between fibers) can be made extremely difficult to occur. Moreover, since the triaxial fabric prepreg 31 and the UD prepreg 32 include reinforcing fibers in different directions, mutual twist deformation can be suppressed.

  Further, since the triaxial woven prepreg 31 and the UD prepreg 32 (32a, 32b) having different fiber directions are not wound as separate layers, they are wound as one set layer, so that one multi-layer set prepreg 30 is provided. As a result, the isotropic property of the golf club shaft 10 can be increased. That is, when the triaxial woven prepreg 31 and the UD prepreg 32 (32a, 32b) are wound as separate layers, the isotropic property of the golf club shaft 10 is merely a simple addition of the isotropic property of each prepreg. However, if the triaxial woven prepreg 31 and the UD prepreg 32 (32a, 32b) are continuously wound in an overlapping state, the prepreg to be used is exactly the same, but each prepreg has a simple isotropic addition. High isotropy that greatly exceeds the combination is expressed. Thereby, the golf club shaft 10 having a hit feeling close to that of a highly isotropic steel shaft can be obtained.

  In addition, when the multi-layer set prepreg 30 is viewed as one prepreg of the triaxial woven prepreg 31 and the UD prepreg 32 (32a, 32b), the front and back of each prepreg are separated over two rotations (circumferences). Since the prepregs in the fiber direction are positioned, displacement between layers of each prepreg (shift between fibers of each prepreg after heat curing) can be suppressed, and thus torsional rigidity can be increased. That is, as a result of the triaxial woven prepreg 31 and the UD prepreg 32 (32a, 32b) that are adjacent to each other being pressed against each other to restrict movement, it is possible to suppress torsional rigidity (displacement between fibers) and increase torsional rigidity. .

Reinforcing fibers included in the prepreg constituting the compression rigidity holding layer 11 and the bending rigidity holding layer 12, and the triaxial woven prepreg 31 and the UD prepreg 32, in addition to carbon fibers, alumina fibers, aramid fibers, tyrano fibers, amorphous Fiber, glass fiber, or the like can be used. That is, the type of yarn is not basically limited.
The thickness of the yarn is preferably 3K (1K is 1000 filaments) or less. If it exceeds 3K, the prepreg becomes too thick, and there is a possibility that a sufficient fiber density (the number of driven wires) cannot be ensured, and the workability around the mandrel may be deteriorated.
As the resin impregnated into the reinforcing fiber, basically any resin can be used. For example, an epoxy resin, an unsaturated polyester resin, a phenol resin, a vinyl ester resin, a peak resin, or the like can be used.
The thickness of the prepreg is preferably 0.02 to 0.25 mm for a UD prepreg, and preferably 0.06 to 0.30 mm for a woven prepreg. If the thickness of the UD prepreg (woven fabric prepreg) is less than 0.02 mm (0.06 mm), it is difficult to obtain good rigidity. If the thickness exceeds 0.25 mm (0.30 mm), the length of the shaft increases. There is a risk of variation in rigidity.
The weight of the prepreg is preferably 400 g / m ² or less. If it exceeds 400 g / m ² , it becomes too thick and it is difficult to wind it around a mandrel.
The resin amount of the prepreg is preferably 20 to 50% by weight for the UD prepreg, and preferably 30 to 60% by weight for the woven prepreg. If the resin amount of the UD prepreg (textile prepreg) is less than 20% by weight (30% by weight), the resin amount is too small to produce a good shaft, and if it exceeds 50% by weight (60% by weight) If the shaft has the same weight, sufficient torsional rigidity may not be exhibited.

  The number of windings of the multi-layer set prepreg 30 in the illustrated example is “2”, but it should be “2” or more based on the performance required for the shaft in consideration of the physical properties of the reinforcing fiber and the thermosetting resin. Can do.

(Embodiment 2)
FIG. 5 is a schematic cross-sectional view of a golf club shaft 40 according to the second embodiment of the present invention. In this embodiment, two two-turn, multi-layer set prepregs 30 described in FIGS. 1 to 4 are provided (two torsional rigidity retaining layers 20 are provided), and the winding directions are opposite to each other. (If one is clockwise, the other is counterclockwise). According to the golf club shaft 40 thus configured, the directionality due to winding can be eliminated, and further, deformation and displacement between the layers in the circumferential direction can be more reliably prevented. That is, the uniformity of the torsional rigidity retaining layer 20 in the circumferential direction is increased, the strength is increased, and the appearance is improved.

(Embodiment 3)
FIG. 6 is a schematic cross-sectional view of a golf club shaft 50 according to the third embodiment of the present invention. In this embodiment, a multi-layer set prepreg 60 is prepared by laminating a plain woven fabric (biaxial woven fabric) prepreg 41 and a UD prepreg 32 in which a plain woven fabric (biaxial woven fabric) is impregnated with a thermosetting resin. The prepreg 60 is continuously wound twice on the multi-layer set prepreg 30 described with reference to FIG. 1 and in the opposite direction to the multi-layer set prepreg 30.

  7 and 8 are conceptual diagrams of the plain woven fabric 4 included in the plain woven fabric prepreg 41. FIG. The plain woven fabric 4 has a structure in which wefts 4a and warps 4b orthogonal to each other are woven, and the wefts 4a and warps 4b are wound so as to form an ideal 45 ° with respect to the longitudinal direction of the shaft. Since the mandrel is conical, the angle between the weft 4a and the warp 4b and the longitudinal direction of the shaft may slightly deviate from 45 ° depending on the winding mode, but the angle between the weft 4a and the warp 4b is 90 °. Because it is stable.

  Instead of the triaxial woven prepreg 31 or the plain woven prepreg 41 of the above embodiment, a tetraaxial woven prepreg obtained by impregnating a tetraaxial woven fabric with a thermosetting resin may be used. FIG. 9 shows the four-axis woven fabric 5 included in the four-axis woven fabric prepreg. The vertical axis thread 5a parallel to the longitudinal direction of the shaft, the horizontal axis thread 5b orthogonal to the vertical axis thread 5a, and the vertical axis thread 5a. And oblique shaft yarns 5c and 5d that obliquely intersect at an angle (for example, 45 ° and −45 °) with respect to the horizontal shaft yarn 5b. The shaft yarns 5c and 5d are woven alternately above and below the yarn. A pentagonal gap 5P is formed between the vertical axis thread 5a, the horizontal axis thread 5b, and the oblique axis threads 5c and 5d. By impregnating such a four-axis fabric 5 with an uncured thermosetting resin, a four-axis fabric prepreg is obtained. The angle at which the vertical axis thread 5a (horizontal axis thread 5b) and the oblique axis thread 5c (5d) intersect is not limited.

In the above embodiment, the multi-layer set prepreg is composed of a combination of a triaxial woven prepreg and a UD prepreg, a combination of a plain woven prepreg and a UD prepreg, or a combination of a four-axis woven prepreg and a UD prepreg. In the present invention, basically, reinforcing fibers in different directions may be included in the plurality of prepregs in the multi-layer set prepreg. Examples of possible prepreg combinations are shown in Table 1.

  Even if a multi-layer set prepreg is constituted by any combination, the prepreg used is completely the same as compared to the case where each prepreg is wound as a separate layer, but the prepreg used has a simple isotropic property. High isotropy that greatly exceeds the addition is expressed. In addition, as a result of the prepregs adjacent to each other being pressed against each other to restrict the movement, the displacement between layers (the displacement between fibers) can be suppressed, and the torsional rigidity can be increased.

  Further, the multi-layer set prepreg includes a 0 ° layer UD prepreg whose fiber direction is parallel to the longitudinal direction of the shaft, and a 90 ° layer UD prepreg whose fiber direction is perpendicular to the longitudinal direction of the shaft. Thus, the torsional rigidity holding layer can be given rigidity against compression (crushing) and bending.

  In the above embodiment, the compression rigidity holding layer 11, the torsion rigidity holding layer 20, the bending rigidity holding layer 12 and the decorative layer 13 are arranged in order from the lower layer (inner side). Has a degree of freedom. For example, the arrangement of the compression rigidity holding layer 11 and the torsion rigidity holding layer 20 is changed, and the torsion rigidity holding layer 20, the compression rigidity holding layer 11, the bending rigidity holding layer 12 and the decorative layer 13 are arranged in order from the lower layer (inner side). May be.

10 40 50 Golf club shaft 11 Compression rigidity (collapse rigidity) retaining layer 12 Bending rigidity retaining layer 13 Cosmetic layer (polishing layer, bending rigidity retaining layer)
20 Torsional rigidity retaining layer 30 60 Multi-layer set prepreg 31 Triaxial fabric prepreg 32 UD prepreg 32a 32b Inclined UD prepreg 3 Triaxial fabric 41 Plain woven fabric (biaxial woven fabric) Prepreg 4 Plain woven fabric (biaxial woven fabric)
5 Four-axis fabric

Claims (6)

In a golf club shaft having a torsional rigidity holding layer of a thermosetting resin provided with reinforcing fibers oblique to the longitudinal direction of the shaft,
The torsional rigidity holding layer includes a multi-layer set prepreg in which at least three prepregs obtained by impregnating a reinforcing fiber with a thermosetting resin are included,
The prepreg of at least three layers in the multi-layer set prepreg includes reinforcing fibers in different directions, and the multi-layer set prepreg is continuous with the at least three layers of prepreg being stacked. A golf club shaft characterized by being wound two or more times. The golf club shaft according to claim 1,
A golf club shaft in which the multi-layer set prepreg includes three layers of a UD prepreg in which a reinforcing fiber having a fiber direction aligned in one direction is impregnated with a thermosetting resin. The golf club shaft according to claim 2,
Two of the three UD prepregs are golf club shafts comprising a pair of inclined UD prepregs with symmetrical fiber directions with respect to the shaft longitudinal direction. The golf club shaft according to claim 3,
The remaining one of the three UD prepregs is a golf club shaft made of a UD prepreg whose fiber direction is perpendicular to the longitudinal direction of the shaft. The golf club shaft according to claim 3,
The remaining one of the three UD prepregs is a golf club shaft made of a UD prepreg whose fiber direction is parallel to the longitudinal direction of the shaft.   6. A golf club having a club head and a grip mounted on the golf club shaft according to claim 1.

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