JP2005176960A - Golf club shaft - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a golf club shaft to be hardly crushed or broken, with sufficient durability and flexibility and excellent feeling for a user in using the shaft. <P>SOLUTION: The golf club shaft comprises a bias layer consisting of prepreg sheets 20 and 22 whose direction of fiber orientation is inclined to the axis of the shaft, a straight layer consisting of a prepreg sheet 24 whose direction of fiber orientation is along the axis, a hoop layer consisting of a prepreg sheet 26 whose direction of fiber orientation orthogonally crosses the axis of the shaft disposed in the range at least 70% from the batting side of the shaft, and a reinforcing layer consisting of prepreg sheets 28 and 30 disposed on the tip side of the shaft. The layers are formed in the order, and the maximum value of the flexural rigidity of the shaft is set in the range from 30 to 70 Nm<SP>2</SP>. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a golf club shaft composed of a plurality of fiber reinforced resin layers.

  In recent years, many golf club shafts composed of a plurality of fiber reinforced resin (FRP) layers have been used. Such a golf club shaft is excellent in strength, has a high degree of freedom in designing weight, bending rigidity, kick point, and the like, and can provide a golf club that widely meets the needs of golfers.

  A golf club shaft made of a fiber reinforced resin layer is a so-called sheet in which, for example, a reinforced fiber such as carbon fiber is oriented in one direction, impregnated with an epoxy resin or the like to form a prepreg sheet, and the sheet is wound a plurality of times. Manufactured by winding method.

  In this case, each layer formed from the prepreg sheet includes two sets of bias layers in which the fiber orientation directions are inclined with respect to the shaft axis, and a straight layer in which the fiber orientation directions are set parallel to the shaft axis. Generally, it is configured by combining. In particular, for lightweight shafts, there are prepreg sheets with low resin content or those with a small number of windings of the prepreg sheet. In order to ensure the strength of the shaft, in addition to the bias layer and straight layer In this case, a hoop layer in which the fiber orientation direction is substantially orthogonal to the axis of the shaft has been proposed (see Patent Documents 1 to 3).

Japanese Utility Model Publication No. 5-13473. JP-A-9-140840 Japanese Patent Laid-Open No. 11-19257

  However, in each of the above prior arts, although an effect of improving the crushing strength of the shaft by arranging the hoop layer is expected, consideration is given to characteristics other than the crushing strength, such as durability and flexibility. There is a concern that other properties required for the shaft are sacrificed.

  The present invention has been made in view of the above-described problems, and does not cause crushing or cracking of the shaft, has sufficient durability and flexibility, and has a very good feeling when used. The purpose is to provide.

The golf club shaft of the present invention is a golf club shaft composed of a plurality of fiber reinforced resin layers.
A hoop layer that is at least 70% in range from the butt side end of the shaft to the tip side, is disposed in the outermost layer on the butt side, and the fiber orientation direction is set substantially orthogonal to the shaft axis;
A reinforcing layer disposed on the tip side of the shaft;
The maximum value of the bending rigidity of the shaft is set in the range of 30 to 70 Nm ² .

According to the present invention, the strength of the shaft is improved by disposing the hoop layer, while the resin content and thickness of each fiber reinforced resin layer are adjusted, and the maximum bending rigidity value of the shaft is set to 30 to 70 Nm. ^By setting it in the range of ² , the durability of the shaft can be ensured and the flexibility can be improved, and the feeling of the golf club using this shaft can be made extremely good.

  FIG. 1 shows a wood-type golf club 12 using the golf club shaft 10 of the present embodiment. The golf club shaft 10 is configured to be gradually reduced in diameter from the butt end side where the grip 14 is mounted to the tip end side where the head 16 is mounted.

  As shown in FIG. 2, the golf club shaft 10 is formed by winding prepreg sheets 20, 22, 24, 26, 28, and 30 made of fiber reinforced resin sequentially from the inside around a mandrel 18 formed in a tapered shape. After heat-curing, the mandrel 18 is extracted and finished by a so-called sheet winding method. The prepreg sheets 20, 22, 24, 26, and 28 and 30 are formed by impregnating a reinforcing fiber such as carbon fiber with a thermosetting resin such as an epoxy resin.

  In the prepreg sheet 20, the orientation direction of the reinforcing fibers 20 a is inclined at + 45 ° with respect to the axis of the golf club shaft 10, and the entire length of the golf club shaft 10 is wound around the outer periphery of the mandrel 18. A two-ply bias layer is formed.

  In the prepreg sheet 22, the orientation direction of the reinforcing fibers 22 a is inclined by −45 ° with respect to the axis of the golf club shaft 10, and the prepreg sheet 22 is wound around the prepreg sheet 20 twice so that the golf club shaft 10 A two-ply bias layer covering the entire length is formed.

  In the prepreg sheet 24, the orientation direction of the reinforcing fibers 24 a is set in the axial direction of the golf club shaft 10, and the prepreg sheet 24 covers the entire length of the golf club shaft 10 by being wound twice on the prepreg sheet 22. Form a straight layer of ply.

  In the prepreg sheet 26, the orientation direction of the reinforcing fibers 26 a is set in a direction substantially orthogonal to the axial direction of the golf club shaft 10, and at least 70% from the butt side end portion to the tip side end portion of the golf club shaft 10. The range is covered, and a one-ply hoop layer is formed by being wound around the prepreg sheet 24 once.

  In the prepreg sheet 28, the orientation direction of the reinforcing fibers 28 a is set in the axial direction of the golf club shaft 10, and the prepreg sheet 28 is wound twice in a predetermined range from the tip side end portion of the golf club shaft 10. Form a ply reinforcement layer. This reinforcing layer compensates for insufficient strength on the tip side of the golf club shaft 10.

  The prepreg sheet 30 formed in a substantially triangular shape has the orientation direction of the reinforcing fibers 30a set in the axial direction of the golf club shaft 10, and is wound around the tip side inserted into the hosel for seven turns. , Forming a reinforcement layer of up to 7 plies. This reinforcing layer, together with the prepreg sheet 28, compensates for insufficient strength on the tip side of the golf club shaft 10, and adjusts the diameter of the golf club shaft 10 inserted into the hosel.

  Here, the surface of the hoop layer formed from the prepreg sheet 26 is not polished. Accordingly, the reinforcing fiber 26a is not broken by the polishing process, and high strength is maintained. Further, the hoop layer prevents the shaft from being crushed or cracked. The hoop layer is formed from a prepreg sheet 26 having carbon fiber, glass fiber or the like as a reinforcing fiber, a resin content such as an epoxy resin of 20 to 50% by weight, and a thickness of 0.01 to 0.05 mm. Since such a prepreg sheet 26 is rich in flexibility and can be easily wound, workability is good. If the resin content is less than 20% by weight, the reinforcing fiber content increases and the rigidity becomes high, so that winding becomes difficult. If the resin content is more than 50% by weight, it is difficult to reduce the weight of the golf club shaft 10. Furthermore, when the thickness is made thicker than 0.05 mm, it is difficult to reduce the weight of the golf club shaft 10.

  The reinforcing layer formed from the prepreg sheet 28 may be disposed in a portion where the hoop layer formed from the prepreg sheet 26 is not present, but the reinforcing layer and the hoop layer may be disposed so as to overlap each other. . Therefore, the hoop layer can be disposed so as to cover the entire length of the golf club shaft 10.

  The bias layer and the straight layer are made of carbon fiber, glass fiber, or the like as reinforced fibers, and the prepreg sheets 20, 22 and 24 having a resin content such as epoxy resin of 15 to 25% by weight and a thickness of 0.04 to 0.09 mm. Formed from. Even in the case of the prepreg sheets 20, 22, and 24 having a resin content smaller than that of the prepreg sheet 26 used for the hoop layer, the workability of winding is greatly reduced by setting the resin content to 15% by weight or more. In addition, the weight of the golf club shaft 10 can be reduced by setting the resin content to 25% by weight or less. If the thicknesses of the prepreg sheets 20, 22 and 24 are less than 0.04 mm, the number of windings must be increased in order to obtain sufficient strength, and workability is reduced accordingly. If the thickness is greater than 0.09 mm, the step between the winding start and the winding end of the prepreg sheets 20, 22, and 24 becomes large, and the strength decreases due to stress concentration at that portion.

  Next, examples of the present invention will be described.

  Table 1 shows the material and the number of constituent layers of each layer constituting Examples 1 and 2 of the golf club shaft of the present invention, and the material and the number of constituent layers of each layer constituting Comparative Examples 1 to 3. The bias layer is formed from prepreg sheets 20 and 22, the straight layer is formed from prepreg sheet 24, the hoop layer is formed from prepreg sheet 26, and the reinforcing layer is formed from prepreg sheets 28 and 30. To do. Note that Comparative Example 2 does not have a hoop layer.

  Table 2 shows the range of the hoop layer, the weight of the shaft, the characteristics of the shaft, and the characteristics of the golf club using each shaft in Examples 1 and 2 and Comparative Examples 1 to 3. In Example 1, the reinforcing layer formed from the prepreg sheet 28 is in a range of 21% from the tip end portion of the shaft.

  In Table 2, the SG bending strength is a value measured by a three-point bending test defined by the SG standard of the Product Safety Association, and T is a load point at a position 90 mm from the tip side end of the shaft. The left and right positions are 75 mm as fulcrums, A is 175 mm from the tip end of the shaft, B is 525 mm from the tip end of the shaft, and C is from the butt end of the shaft. The 175 mm position is a load point, and the left and right 75 mm positions of each load point are fulcrums. The bending strength is measured when a bending load is applied in a direction perpendicular to the shaft axis.

FIG. 3 shows the bending stiffness value EI at each position of the shaft having the configuration of Example 1 and Comparative Example 3. The bending stiffness value EI is defined as the load load W, the span between fulcrums L, and the shaft deflection amount y in the three-point bending stiffness test.
^{EI = W · L 3/48} · y
The rigidity value obtained as

  Table 3 shows the results of an actual hit test using a swing robot device for a golf club using a shaft having the configuration of Example 1 and Comparative Example 3.

  In this case, the golf club shafts 10 of Examples 1 and 2 passed the three-point bending test (SG pass / fail: ◯), and as a result of performing an actual hitting test with a golf club using this shaft, it was easy to swing. Was evaluated as being good. In addition, the determination of SG pass / fail determines that the SG bending strength at the load point position T is 800 N or more and the bending strength at the load point positions A, B, and C is 400 N or more as pass (◯). . On the other hand, the golf club using the shaft of Comparative Example 3 was evaluated as bad in terms of ease of swinging.

  Further, when a golf club using the shaft of Example 1 was mounted on a swing robot apparatus and an actual hit test was performed, a better result than Comparative Example 3 was obtained in the head speed, the initial ball speed, and the carry. In addition, about spin amount, Example 1 is smaller than the comparative example 3, Therefore, it is assumed that the trajectory which a golfer desires is easy to be obtained.

  Furthermore, as shown in FIG. 3, it is understood that the rigidity of the shaft of Example 1 is smaller than the rigidity of the shaft of Comparative Example 3 at any part of the shaft, and therefore a golf club shaft 10 that can be easily bent is obtained. The

This is a golf club using the golf club shaft of the present embodiment. It is explanatory drawing of each prepreg sheet | seat which comprises the golf club shaft of this embodiment. It is comparison explanatory drawing of the rigidity distribution of the golf club shaft of an Example and the golf club shaft of a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Golf club shaft 12 ... Golf club 20, 22, 24, 26, 28, 30 ... Prepreg sheet

Claims (2)

In a golf club shaft composed of a plurality of fiber reinforced resin layers,
A hoop layer that is at least 70% in range from the butt side end of the shaft to the tip side, is disposed in the outermost layer on the butt side, and the fiber orientation direction is set substantially orthogonal to the shaft axis;
A reinforcing layer disposed on the tip side of the shaft;
And a maximum value of the bending rigidity of the shaft is set in a range of 30 to 70 Nm ² . The golf club shaft according to claim 1,
The hoop layer is formed from a prepreg sheet having a resin content of 20 to 50% by weight and a thickness of 0.01 to 0.05 mm.
The golf club shaft, wherein the fiber reinforced resin layer excluding the hoop layer and the reinforcing layer is formed of a prepreg sheet having a resin content of 15 to 25% by weight and a thickness of 0.04 to 0.09 mm.

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