JP2004121402A - Golf club shaft - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a golf club shaft, especially in the lightweight golf club shaft, sufficiently enhancing strength properties in such a manner that hoop layers are disposed in a position to prevent buckling more effectively so that wrinkles are never generated on hoop layer sheets not to cause a lack in the designed number of winding and that irregularity of orientation angles caused by generation of fiber disorder never occurs not to decrease a bending strength, and that an operating efficiency when layering and winding the hoop layers is not obstructed. <P>SOLUTION: In the golf club shaft 1, from the innermost layer, a plus bias layer 2, a minus bias layer 3 and the hoop layers 4 are disposed and laminated in turn, and knitting layers 5 in which toe prepregs are knitted are disposed as the outer layers thereof. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a golf club shaft made of fiber reinforced resin that has sufficient compressive fracture strength against bending stress and is easy to manufacture.
[0002]
[Prior art]
A golf club shaft made of fiber reinforced resin is formed by laminating a fiber reinforced resin layer impregnated with a synthetic resin into a reinforced fiber on a mandrel, curing the synthetic resin by heating it, and then extracting the mandrel. doing.
Such a golf club shaft can be significantly reduced in weight compared to a metal golf club shaft and has a large degree of freedom in design such as being able to set torsional rigidity and bending rigidity relatively freely. in use.
[0003]
Conventionally, when a golf club shaft is formed using a so-called prepreg sheet in which a reinforcing fiber is impregnated with a synthetic resin, a straight prepreg in which the orientation angle of the reinforcing fiber is arranged substantially parallel to the shaft axis is wound. And a bias layer formed by winding a bias prepreg arranged so that the orientation angle of the reinforcing fiber intersects the shaft axis.
Recently, golf club shafts tend to be lighter. For example, in order to form a lightweight golf club shaft of 50 g or less, it is necessary to reduce the thickness of the fiber reinforced resin layer. As a result, the compressive fracture strength of the golf club shaft, that is, the fracture strength on the compression side caused by the bending load acting on the cylinder and flattening of the cross section is insufficient, which is a factor in reducing the bending strength. It was easy to break. That is, in the case of the light weight golf club shaft, the compression fracture strength is weakened by reducing the thickness. Therefore, when a bending stress is applied in the process of bending the golf club shaft, the compression fracture first occurs.
[0004]
Therefore, in the case of a lightweight golf club shaft, as a method for obtaining a sufficiently satisfactory bending strength, in addition to the configuration of the straight layer and the bias layer described above, in order to further increase the compressive fracture strength, A hoop layer formed by winding a hoop prepreg disposed so as to be substantially orthogonal is provided.
[0005]
[Problems to be solved by the invention]
Since the hoop layer has little contribution to various characteristics of the golf club shaft such as bending characteristics and torsion characteristics, a thin prepreg sheet is used. In order to wind such a hoop prepreg around a molding mandrel, when peeling the shape-retaining release paper bonded to the hoop prepreg, or when winding the peeled hoop prepreg around the mandrel Since the thickness of the prepreg is thin and the reinforcing fibers are arranged in a direction perpendicular to the molding winding direction, the working efficiency is at a low level compared to other sheets. When the work efficiency is reduced, wrinkles are generated in the sheet and the intended number of windings is insufficient, or fiber orientation is disturbed and the orientation angle varies, which may affect the winding state, If they occur, it may cause a decrease in bending strength due to manufacturing variations, and the possibility of insufficient bending strength in the case of a lightweight golf club shaft also appears.
[0006]
On the other hand, with emphasis on work efficiency, for example, as in the present invention, even when the hoop prepreg is bonded to the bias prepreg and laminated and wound, the hoop prepreg is placed on the inner layer side without limit. Since the diameter of the layer is small, the effect of suppressing the maximum axial stress generated by the flattening of the cross section is small, and as a result, the effect of preventing compression failure is small, so that the original effect of the hoop layer is sufficient. It will also lead to the fact that the effect on the strength performance is not fully demonstrated.
[0007]
Therefore, in the present invention, the position at which the hoop layer is disposed is disposed at a position where the effect of preventing further compression failure is obtained, and the work efficiency at the time of laminating and winding the hoop layer is not impaired. Provided is a golf club shaft in which the bending strength inherent to the golf club shaft can be stabilized and sufficiently satisfactory can be obtained by suppressing the variation to sufficiently exhibit the strength performance. For the purpose.
[Means for Solving the Problems]
[0008]
In order to achieve the above object, the invention according to claim 1 is a golf club shaft in which a fiber reinforced resin layer formed by impregnating a reinforced fiber with a synthetic resin is laminated, and the orientation angle of the reinforced fiber is defined as a shaft axis. A golf club shaft having a hoop layer disposed outside the bias layer arranged so as to intersect with the bias layer so that the orientation angle of the reinforcing fibers is substantially perpendicular to the shaft axis adjacent to the bias layer.
[0009]
According to a second aspect of the present invention, in the golf club shaft according to the first aspect, the hoop layer is at least one round with respect to the circumferential direction of the shaft and is wound approximately an integral number of times. .
[0010]
A third aspect of the present invention is the golf club shaft according to the first or second aspect, wherein the hoop sheet is disposed over the entire length in the shaft axial direction of the golf club shaft.
[0011]
A fourth aspect of the present invention is the golf club shaft according to the first or second aspect, wherein the hoop sheet is partially disposed in a shaft axial direction of the golf club shaft.
[0012]
According to a fifth aspect of the present invention, in the golf club shaft according to the first, second, third, or fourth aspect, a yarn made of a bundle of reinforcing fibers impregnated with a resin is braided outside the hoop layer. A golf club shaft having a braided layer.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on preferred embodiments shown in the drawings. FIG. 1 is a partially explanatory perspective view illustrating the configuration of a golf club shaft 1 as one embodiment according to the present invention. FIG. 2 is a development view of a prepreg sheet used for the golf club shaft 1.
[0014]
The golf club shaft shown in FIG. 1 is a golf club shaft 1 formed by laminating a fiber reinforced resin layer, and the fiber reinforced resin layer includes a fiber reinforced prepreg sheet obtained by impregnating a reinforced fiber with a synthetic resin. The + bias layer 2 is arranged with the orientation angle of the reinforcing fibers oriented in the + direction with respect to the shaft axis, and the − bias layer 3 is arranged with the orientation angle symmetrical to the + bias layer 2 with respect to the shaft axis. The hoop layer 4 arranged so as to be substantially orthogonal to the shaft axis is sequentially laminated.
[0015]
Each of the layers 2 to 4 is composed of a prepreg sheet in which reinforcing fibers are aligned in one direction and impregnated with a molding synthetic resin, and carbon fibers are used as the reinforcing fibers.
The + bias layer 2 has the carbon fiber orientation angle of the prepreg sheet in the range of + 35 ° to + 55 ° with respect to the shaft axis, and the −bias layer 3 has the carbon fiber orientation angle of the shaft axis. In contrast, bias prepregs having a range of −35 ° to −55 ° are arranged so as to cross each other. The hoop layer 4 is arranged as a hoop prepreg in which the orientation angle of the carbon fiber is in the range of 90 ° ± 10 ° with respect to the shaft axis.
As shown in FIG. 2, when the golf club shaft 1 is wound around the mandrel 6 when the bias prepreg 20 and the bias prepreg 30 are bonded to each other so that the reinforcing fibers cross each other and shifted by a half circumference, After the hoop prepreg 40 is pasted to the outside of the bias sheet 30 by a half turn, these are wound around the mandrel 6 in order, laminated, wrapped with a wrapping tape, heated and cured, and then the surface wrapping tape is peeled off. Molded as a club shaft.
[0016]
The maximum axial stress generated when a bending load is applied to the cylinder and the cross-section is flattened decreases as the diameter at which the hoop layer is located increases. In other words, the effect of preventing compressive fracture is increased by disposing the hoop layer on the outer side, and by providing a hoop layer on the outer side and adjacent to the bias layer as in the present invention, sufficient compressive fracture strength can be obtained. Thus, a lightweight golf club shaft can be obtained.
[0017]
Further, when the prepreg sheet is wound, the bias prepreg 20 and the bias prepreg 30 are bonded to each other so that the reinforcing fibers cross each other and are shifted by a half circumference, and when the prepreg sheet is wound around the mandrel, the bias prepreg is turned outside. In the hoop prepreg 40 in which the reinforcing fibers are arranged in a direction substantially perpendicular to the shaft axis direction, the work is wound around the mandrel while the hoop sheet 4 is bonded to the outer side of the hoop sheet 4 while being shifted by a half turn. Since it is wound integrally with the prepreg 30, the releasability of the release paper is improved, and the forming and winding work is facilitated without causing fiber disturbance, and the resin content or the prepreg thickness, that is, the work efficiency is affected. Stable work efficiency can be obtained without being affected by the physical properties of the prepreg that is It is.
[0018]
In the present invention, the hoop layer 4 is preferably wound by an integer number of one or more layers. Since the hoop layer 4 is intended to improve the circular tube compression characteristics of the golf club shaft, in order to develop a sufficient compressive fracture strength, the shaft cross-section exceeds at least one turn and is approximately an integer number of turns. It is desirable to become. When it is less than one round, a sufficient effect for flattening the cross section cannot be obtained. When the number is less than one round, the ratio of the strength effect to the mass is small, resulting in an excessive mass increase, which is not preferable.
[0019]
Further, the hoop layer can be partially arranged as shown in FIG. 3 in addition to being arranged over the entire length of the shaft as shown in FIG. In the tip end side of the shaft, that is, in the range where the outer diameter is small, the hoop layer is less likely to be flattened because the cross section is difficult to flatten. It is also possible to arrange from the center to the grip end.
[0020]
The present invention provides a golf club shaft having a structure in which a hoop layer is laminated on the outer side of a bias layer as described above, and the orientation angle of the reinforcing fibers is further outside the fiber reinforced resin layer having such a structure. In addition to a golf club shaft in which a straight layer made of a straight sheet that is substantially parallel to the shaft axis is arranged, as shown in FIG. 1, a yarn made of a bundle of reinforcing fibers impregnated with resin is braided. The same effect can be obtained as a golf club shaft in which the assembled braid layer 5 is disposed outside.
[0021]
【Example】
FIG. 4 shows an example of a golf club shaft using a prepreg sheet and a braided layer as an example.
This golf club shaft 1 has a + bias layer 2, a -bias layer 3 and a hoop layer 4 arranged in order from the innermost layer and laminated, and a braided layer 5 in which a tow prepreg is braided is arranged on the outer layer. Yes. This braided layer 5 is made of carbon fiber tow prepreg, and the tow prepreg is gradually changed from the front end to the rear end so as to have an orientation angle of about 50 degrees to about 30 degrees with respect to the shaft 7. A biaxial braid layer 8 braided over the entire length of 8 braids, and 8 braids arranged by gradually changing the orientation angle with respect to the shaft 7 from about 30-40 degrees to about 10 degrees. The biaxial braid layer 9 is braided over the entire length, and the shaft axis 2 is gradually changed from the front end to the rear end so that the orientation angle is about 20 to 30 degrees to about 10 degrees. A triaxial braided layer 10 braided with 16 braids and eight central yarns arranged at approximately 0 degrees with respect to the shaft 2 and about 20-30 degrees with respect to the shaft 2 from about 10 degrees. A set arranged with gradually changing the orientation angle of the range The 16 was formed by braid layer 11 of the two axes was braided.
[0022]
Specifically, as the bias layers 2 and 3, a prepreg was obtained by impregnating a carbon fiber having a tensile elastic modulus of 390 GPa as a reinforcing fiber with a synthetic resin so that the resin content was 25 wt%. The thickness of the prepreg is 0.103 mm. As the hoop layer 4, a prepreg was obtained by impregnating a carbon fiber having a tensile elastic modulus of 300 GPa as a reinforcing fiber with a synthetic resin so that the resin content was 30 wt%. The prepreg thickness is 0.028 mm. The orientation angles of the reinforcing fibers of the bias layers 2 and 3 are + 45 ° and −45 ° with respect to the shaft axial direction.
[0023]
The braided layer 5 converges 6000 to 12000 carbon fibers having 300 tex to 800 tex as reinforcing fibers and a tensile elastic modulus of 240 GPa to 480 GPa so that the resin content of the molding resin is 30 wt% or more and 45 wt% or less. A tow prepreg was used. As the molding resin, those similar to the synthetic resins conventionally used for FRP molded products can be used. For example, thermosetting resins such as epoxy resin, polyester resin, phenol resin, polypropylene resin, polyether ether, etc. A thermoplastic resin such as a ketone resin, ABS resin, or nylon resin can be used, but an epoxy resin is preferably used.
[0024]
FIG. 5 is a view showing the configuration of a golf club shaft of a comparative example. The materials and configurations used are the same except that the hoop layer 4, + bias layer 2, and −bias layer 3 are sequentially arranged from the innermost layer. The laminated structure is the same as that of the example.
[0025]
FIG. 6 is a graph showing the results of a three-point bending test of the golf club shafts of the present example and the comparative example. In this graph, the horizontal axis indicates the name of the part of the golf club shaft, and the vertical axis indicates the maximum point load when the golf club shaft is broken. Further, point A in FIG. 6 is a position that is approximately ¼ of the total length from the tip a of the golf club shaft shown in FIG. 7, point B is a position that corresponds to approximately the center of the total length of the golf club shaft, point C Indicates a position of approximately ¼ of the total length from the rear end c of the golf club shaft. The three-point bending test was performed for the points A, B, and C with reference to the three-point bending test method indicated in the SG (Product Safety Association) standard.
[0026]
As shown in FIG. 6, it can be seen that the value of the golf club shaft of the example exceeds the value of the golf club shaft of the comparative example at any of the points A, B, and C at the maximum point load.
[0027]
More specifically, the effect of providing a hoop layer to prevent compression failure is greater at the shaft large diameter side, that is, at points B and C, while at point A, the effect is small. In the case of aiming, it is also an effective design means that the hoop layer is removed within a range of about ¼ to ３ of the entire length from the tip a to partially dispose.
[0028]
【The invention's effect】
Since this invention is comprised as mentioned above, there exists an effect described below.
That is, the effect of preventing compression failure is increased by arranging the hoop layer on the outer side, and a lightweight golf club shaft made of fiber reinforced resin having sufficient compression failure strength by molding the golf club shaft as described above. Is obtained. Regarding the number of windings of the hoop layer, at least one round in the cross section of the shaft and approximately an integer number of windings, the increase in mass due to the arrangement of the hoop layer is minimized, and more sufficient a compression fracture strength is obtained. A lightweight golf club shaft made of fiber-reinforced resin is obtained.
[0029]
Further, since the hoop prepreg is wound integrally with the bias prepreg, the release paper is improved in peelability, and the winding operation is facilitated without causing fiber disturbance, and the resin content, or the prepreg thickness, That is, since the stable work efficiency can be obtained without being affected by the prepreg physical property values that affect the work efficiency, the degree of freedom in design is increased.
When further reducing the weight, it is possible to reduce the weight by removing the hoop layer and placing it partially within the range of about 1/3 of the shaft tip side, which has a relatively small effect on preventing compression failure. It becomes.
[Brief description of the drawings]
FIG. 1 is a partially explanatory perspective view illustrating a configuration of a golf club shaft 1. FIG.
FIG. 2 is a development view of a prepreg sheet used for the golf club shaft 1;
FIG. 3 is another development view of the prepreg sheet used for the golf club shaft 1;
FIG. 4 is a partial explanatory perspective view illustrating a specific configuration of the golf club shaft 1;
FIG. 5 is a partial explanatory perspective view illustrating a specific configuration of a golf club shaft of a comparative example.
FIG. 6 is a graph showing the test results of three-point bending and test and cantilever bending strength of golf shafts of examples and comparative examples.
FIG. 7 is an overall explanatory view of a golf club shaft.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Golf shaft 2 Bias layer 3 Bias layer 4 Hoop layer 5 Assembly layer 6 Mandrel 7 Shaft shaft 8 Assembly layer 9 Assembly layer 10 Assembly layer 11 Assembly layer 20 Bias prepreg 30 Bias prepreg 40 Hoop prepreg a Tip c After end

Claims (5)

A golf club shaft in which a fiber reinforced resin layer obtained by impregnating a reinforced fiber with a synthetic resin is laminated, wherein the bias is disposed outside a bias layer arranged so that the orientation angle of the reinforced fiber intersects the shaft axis. A golf club shaft comprising a hoop layer disposed adjacent to the layer so that the orientation angle of the reinforcing fibers is substantially perpendicular to the shaft axis. 2. The golf club shaft according to claim 1, wherein the hoop layer is wound at least one round and approximately an integer number of times in the circumferential direction of the shaft. The golf club shaft according to claim 1, wherein the hoop layer is disposed over the entire length in the shaft axial direction of the golf club shaft. The golf club shaft according to claim 1, wherein the hoop layer is partially disposed in a shaft axial direction of the golf shaft. 5. The golf according to claim 1, further comprising a braided layer formed by braiding yarns made of a bundle of reinforcing fibers impregnated with a resin outside the hoop layer. Club shaft.

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