JP2528596Y2 - Golf club carbon shaft - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carbon shaft for a golf club, and more particularly to a carbon shaft for a golf club in which the strength of a lightweight shaft against impact or bending is improved.

[0002]

2. Description of the Related Art Conventionally, a golf club carbon shaft, particularly a lightweight shaft, formed by a generally used sheet winding method has a bias layer 1 in which reinforcing fibers are inclined with respect to the longitudinal direction of the shaft as shown in FIG. Are laminated inside a plurality of layers (six layers) so that the orientation angles of the reinforcing fibers intersect each other, and a plurality of straight layers 2 (two layers) in which the reinforcing fibers are parallel to the longitudinal direction of the shaft are laminated outside the layers. ing.

In order to prevent buckling breakage due to bending moment, surface pressure or the like, a hoop layer 3 in which reinforcing fibers are substantially perpendicular to the longitudinal direction of the shaft intersects reinforcing fibers of the bias layer 1 with each other. A plurality of layers (two layers) are interposed between each two layers.

[0004]

Problems to be Solved by the Invention A hoop layer 3 used for a golf club carbon shaft having the above-described structure.
Since hardly affects the characteristics such as the rigidity of the shaft, an ultra-thin prepreg is used to minimize an increase in weight. Therefore, it is desirable that the hoop layer 3 is disposed at a position where the amount of the hoop layer 3 is minimized and the effect of preventing buckling breakage is greatest.

[0005] The maximum axial stress σ [kg / m in so-called bending buckling due to the bending load acting on the cylinder and the cross section being flattened
m ² ] is σ = M / (Πa ² h). Here, M is the bending moment [kg · mm], and a is the inner diameter of the cylinder [m
m] and h indicate the thickness [mm] of the cylinder. When only the hoop layer is considered, h is constant, and as a, that is, the diameter at which the hoop layer is located increases, the maximum axial stress σ when the same bending moment acts is reduced.

The material outside the hoop layer and its structure are the same,
If the material and the strength of the hoop layer are the same, the effect of preventing the buckling of buckling by placing the hoop layer more outside becomes large. Therefore, in the above-described conventional example, the hoop layer 3 is interposed between the bias layers 1 forming the inside, and as is apparent from the above equation, the hoop layer 3 efficiently reduces buckling breakage due to bending moment and the like. It is hard to say that the hoop layer 3 is well prevented, and since the hoop layer 3 is arranged in two layers, it is hard to say that the usage amount of the hoop layer 3 is kept to a minimum.

The present invention has been devised in view of such conventional problems, and effectively prevents buckling breakage when a bending moment or surface pressure is applied, and minimizes the amount of hoop layer used. Carbon shaft for golf clubs,
In particular, it aims to provide a lightweight shaft.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a bias layer group in which the orientation angles of reinforcing fibers intersect with each other, and the reinforcing fibers are arranged in parallel to the longitudinal direction of the shaft. In a golf club carbon shaft comprising a straight layer group arranged and a hoop layer in which reinforcing fibers are arranged in a direction substantially perpendicular to the longitudinal direction of the shaft , the straight layer group is laminated outside the bias layer group. And counting the hoop layer from the outermost layer
The hoop layer is disposed between straight layers within the third layer.
The orientation angle of the reinforcing fibers of the shaft in the longitudinal direction of the shaft.
The point is that the angle is set to 90 ± 10 degrees .

[0009]

The present invention is configured as described above, and a straight layer group is laminated outside the bias layer group, and the hoop layer is formed.
Between the straight layers within the third layer counting from the outermost layer
And the orientation angle of the reinforcing fibers of the hoop layer is determined by
By setting the angle to 90 ± 10 degrees with respect to the longitudinal direction of the shaft, even if the hoop layer has the same thickness and rigidity,
It can be used extremely efficiently and can effectively prevent buckling fracture when a bending moment or surface pressure is applied.

Further, only one hoop layer, which hardly affects the characteristics such as the rigidity of the shaft, is disposed, and the amount of the hoop layer can be minimized.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a cross-sectional explanatory perspective view showing a main portion of a golf club carbon shaft of the present invention formed by a sheet winding method, and a bias layer 11 in which reinforcing fibers are inclined in the shaft longitudinal direction inside,
Six layers of the reinforcing fibers are stacked so as to cross each other, and three layers of the straight fibers 12 parallel to the longitudinal direction of the shaft are stacked outside the reinforcing fibers.

A hoop layer 13 in which the reinforcing fibers are substantially perpendicular to the longitudinal direction of the shaft has only one layer between the outermost layer of the straight layer 12 and the lower layer adjacent thereto (the first layer counted from the outermost layer). It is arranged sandwiched. The position where the hoop layer 13 is laminated is preferably within the third layer counted from the outermost layer, and the orientation angle of the reinforcing fiber of the hoop layer 13 is 90 ± 10 with respect to the longitudinal direction of the shaft.
Degree is preferred.

[0013] The hoop layer 13 is counted three times from the outermost layer.
The hoop layer 13 is arranged within the layer to increase the diameter of the hoop layer 13 from the viewpoint of preventing buckling.
It is effective that the hoop layer 13 and the straight layer 12 are biased when the third or more layers are formed because the number of stacked straight layers 12 is limited. The layers are stacked between the layers 11 or between the bias layers 11.

The straight layer 12 and the bias layer 11
This is because, if it is arranged between the bias layers 11, the concentration of shear stress due to the difference in rigidity is likely to occur at the interlayer interface, and if it is arranged between the bias layers 11, the same result as the conventional example will be obtained. In addition, the reinforcing fiber orientation angle of the hoop layer 13 being 90 ± 10 degrees with respect to the longitudinal direction of the shaft means that if there is an opening of 10 degrees or more, the reinforcing fibers will be inclined in the longitudinal direction of the shaft, and the bias layer 11 This is because the same operation as the hoop layer 13 in which the reinforcing fibers are orthogonal to the longitudinal direction of the shaft cannot be sufficiently achieved.

However, naturally, the hoop layer 13
Are not strictly limited to the above values. Next, the implemented impact strength test will be described. Using a prepreg sheet in which carbon fibers are impregnated with epoxy resin, a bias layer in which reinforcing fibers are inclined in the longitudinal direction of the shaft is laminated on the inner side, and six layers are laminated so that the reinforcing fibers cross each other. A carbon shaft in which three straight layers parallel to the longitudinal direction are laminated (no hoop layer), a carbon shaft in which one hoop layer is laminated between the straight layers of the carbon shaft (invention shown in FIG. 1), and the hoop A total of three kinds of carbon shafts each having one hoop layer laminated every two layers between the bias layers of the carbon shaft without layers (a conventional example in which two hoop layers were laminated) were subjected to an impact strength test.

However, the thickness of all hoop layers is 0.024 m
m, the outer diameter of the carbon shaft is shifted to the above three types of carbon shafts by shifting the winding position, and a prototype is manufactured under the same conditions except for the strength in the conventional shaft evaluation method except for all the characteristics. The weight difference due to the difference in the number of layers is about 0.5
g or less. The measurement conditions are such that the above-mentioned three types of carbon shafts are cut every 60 mm from the head side of the club, and the impact strength at the intermediate point is measured with a commercially available Izod impact tester.

The measurement results are as shown in the graph of FIG. Here, the horizontal axis represents the distance [mm] of the carbon shaft from the club head side, and the vertical axis represents impact energy [kgf · cm]. As can be seen from the graph of FIG. 2, the carbon shaft for golf clubs of the present invention is 5 [kg] in comparison with the conventional carbon shaft for golf clubs.
f · cm] or more, and it can be said that the impact strength is remarkably improved.

The above three types of carbon shafts are
Cut every 0mm, and set 100mm between spans, JIS
A three-point bending strength test was performed according to K6911 . The measurement results were as shown in the graph of FIG. However,
The horizontal axis indicates the distance [mm] of the carbon shaft from the club head side, and the vertical axis indicates the bending load [kgf].

As can be seen from the graph of FIG. 3, the golf club carbon shaft of the present invention having only one hoop layer exhibits almost the same bending strength as a conventional golf club carbon shaft having two hoop layers. Despite the reduction in the hoop layer, it can be said that the golf club carbon shaft of the present invention has sufficient bending strength.

[0020]

As described above, the carbon shaft for a golf club of the present invention, particularly the lightweight shaft, uses reinforcing fibers.
Arrange in a direction substantially perpendicular to the longitudinal direction of the shaft
Hoop layer, straight within the third layer counting from the outermost layer
Disposed between the layers, the orientation of the reinforcing fibers of the hoop layer
Angle set to 90 ± 10 degrees with respect to the longitudinal direction of the shaft
The following excellent effects are achieved by doing
It is. . Even if the hoop layer has the same thickness and rigidity,
The bending layer and the surface pressure can be arranged very effectively
Prevents buckling failure due to force, etc.
Strength can be improved. . Also, it hardly affects characteristics such as shaft rigidity.
With only one hoop layer and reduce the amount of hoop layer used.
Minimizing the weight increase can be prevented. . In addition, the hoop layer is the third layer or more counted from the outermost layer.
Arrangement between the straight layers inside is to prevent buckling
Effective for increasing the diameter of the hoop layer from
Yes, and hoop between the straight layer and the bias layer
Prevents the layers from locating and shears due to the difference in rigidity at the interlayer interface.
Concentration of shear stress can be prevented. . The orientation angle of the reinforcing fibers in the hoop layer is
By setting to 90 ± 10 degrees to the longitudinal direction,
Prevents reinforcing fibers from tilting in the longitudinal direction of the shaft
Can be used effectively as a hoop layer
I can do it.

[Brief description of the drawings]

FIG. 1 is a cross-sectional explanatory perspective view showing a main portion of a golf club carbon shaft of the present invention.

FIG. 2 is a graph showing the measurement results of the impact strength test of the present invention.

FIG. 3 is a graph showing the measurement results of a three-point bending strength test of the present invention.

FIG. 4 is a cross-sectional explanatory perspective view showing a main part of a conventional golf club carbon shaft.

[Explanation of symbols]

1,11 Bias layer 2,12 Straight layer 3,13 Hoop layer

Claims (1)

(57) [Scope of request for utility model registration] 1. A bias layer group in which the orientation angles of reinforcing fibers intersect each other, a straight layer group in which reinforcing fibers are arranged in parallel to the longitudinal direction of the shaft, in Shaft for golf club comprising a hoop layers arranged in a direction substantially perpendicular to the direction, the straight layer group are laminated on the outer side of the bias layer groups, the hoop layer, three layers counted from the outermost layer Within the eyes
A reinforcing fiber provided in the hoop layer and disposed between the
The orientation angle of the fiber is 90 ± 10 with respect to the longitudinal direction of the shaft.
A carbon shaft for golf clubs, characterized in that the shaft is set at a predetermined temperature.