Golf club shaft

Abstract

The object of the present invention is to provide a golf club shaft that is lightweight but exhibits good durability and can suppress a decrease in flex. The golf club shaft according to the present invention has a mass in the range of 30 g to 60 g. This shaft also exhibits a flex in the range of 8 kg to 20 kg. Furthermore, when a head is attached to the tip of a shaft weighing less than 45 g and a golf ball is hit with the head at a head speed of 38 m / s, the shaft has a durability of 1200 or more strokes, and when a head is attached to the tip of a shaft weighing 45 g or more and a golf ball is hit with the head at a head speed of 44 m / s, the shaft has a durability of 1800 or more strokes.

Description

[Technical field]

[0001] The present invention relates to a shaft for a golf club. [Background technology]

[0002] In recent years, golf club shafts have become lighter in order to improve the distance a ball can fly, and various shaft weight reduction techniques have been proposed in the past (see, for example, JP 2009-229444 A and JP 2012-130533 A). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-229444 A [Patent Document 2] JP 2012-130533 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, when the shaft is made lighter, not only does the durability of the shaft decrease, but the flexibility also decreases (i.e., the shaft becomes more flexible). The object of the present invention is to provide a golf club shaft that is light in weight but has good durability and can suppress the decrease in flexibility. [Means for solving the problem]

[0005] The shaft of the golf club according to the first aspect of the present invention has a mass in the range of 30g to 60g. This shaft also exhibits a flex in the range of 8kg to 20kg. When a head is attached to the tip of a shaft weighing less than 45g and a golf ball is hit with the head at a head speed of 38m / s, the shaft has a durability of 1200 strokes or more, and when a head is attached to the tip of a shaft weighing 45g or more and a golf ball is hit with the head at a head speed of 44m / s, the shaft has a durability of 1800 strokes or more. The length of this shaft is preferably 1170±2mm.

[0006] Therefore, although the shaft is lightweight, it is possible to exhibit good durability and to suppress a decrease in flex.

[0007] A golf club shaft according to a second aspect of the present invention is the golf club shaft according to the first aspect, and is formed by laminating a first prepreg, a second prepreg and an outermost prepreg. The first prepreg has a thickness of 20 g / m 2 More than 100g / m 2 The first prepreg includes a first fiber within the following range. The first prepreg is wound continuously for two or more turns so that the orientation angle of the first fiber is within the range of 80° to 100°. The second prepreg includes a second fiber. The second fiber has a fiber elastic modulus within the range of 350 GPa to 800 GPa. The second prepreg is wound adjacent to the first prepreg on the outside of the first prepreg so that the orientation angle of the second fiber is within the range of ±30° to ±40°. The outermost prepreg includes a third fiber. The third fiber has a fiber breaking elongation within the range of 1.5% to 3.0%. The outermost prepreg is wound outside the second prepreg so that the orientation angle of the third fiber is within the range of -5° to 5°. Another prepreg may be provided between the second prepreg and the outermost prepreg depending on the purpose. In addition, the orientation angle is determined based on the axis of the shaft, that is, the axis of the shaft is set to 0°.

[0008] Therefore, this shaft can be manufactured using conventional prepreg lamination techniques.

[0009] A golf club shaft according to a third aspect of the present invention is the golf club shaft according to the second aspect, further comprising a decorative layer. The decorative layer is made of at least one of paint, print, fabric and a unidirectional fiber sheet. In this case, the decorative layer is the outermost layer of the golf club shaft in terms of layout, but is a completely different layer in terms of function. In addition, the decorative layer is preferably made of a prepreg using fibers with a fiber breaking elongation in the range of 1.5% to 3.0%.

[0010] This allows the shaft to have a distinctive design. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The shaft of the golf club according to the embodiment of the present invention is a so-called lightweight shaft, and when the length is 1170±2 mm, the shaft has a mass within the range of 30 g to 60 g. The mass is preferably within the range of 30 g to 55 g, more preferably within the range of 30 g to 50 g, even more preferably within the range of 30 g to 45 g, and particularly preferably within the range of 30 g to 40 g. However, some golf players may prefer a higher mass.

[0012] This shaft also exhibits a flex within the range of 8 kg or more and 20 kg or less. The preferred range of this flex varies depending on the mass range. When the mass of the shaft is within the range of 30 g or more and 38 g or less, the flex is preferably within the range of 8 kg or more and 10.4 kg or less, when the mass of the shaft is within the range of more than 38 g and 43 g or less, the flex is preferably within the range of 10.5 kg or more and 11.9 kg or less, when the mass of the shaft is within the range of more than 43 g and 49 g or less, the flex is preferably within the range of 12 kg or more and 15.4 kg or less, and when the mass of the shaft is within the range of more than 49 g and 60 g or less, the flex is preferably within the range of 15.5 kg or more and 20 kg or less.

[0013] This shaft also exhibits symmetric torque characteristics that comply with Golf Association regulations.

[0014] In addition, when a head is attached to the tip of a shaft weighing less than 45g and a golf ball is hit with the head at a head speed of 38 m / s, the shaft has a durability of 1200 times or more, and when a head is attached to the tip of a shaft weighing 45g or more and a golf ball is hit with the head at a head speed of 44 m / s, the shaft has a durability of 1800 times or more. In addition, when the mass of the shaft is less than 45g, the durability is preferably 1800 times or more. In addition, in the embodiment of the present invention, the "durability of the shaft" refers to the number of times that no damage such as microcracks is observed on the shaft surface when the shaft surface is observed with an optical microscope after hitting a golf ball with a golf club equipped with the shaft. In addition, the above-mentioned durability is measured by test hitting with a robot with high repeatability such as Golf Shot Robo 3DX manufactured by Miyamae Co., Ltd. The head used in the measurement is Taylormade M1 460 or an equivalent product (e.g., a head having a titanium face and weighing about 200g). It should be noted that in this durability test, the golf balls were heel-hit, so the effect of the head face material was relatively small. The golf balls were Acushnet's Titleist Pro V1 or equivalent (a commercially available ball of about 45.93 g that conforms to the golf rules and has the same hardness as the Titleist Pro V1).

[0015] The shaft of the golf club according to the embodiment of the present invention is formed by laminating a first prepreg, a second prepreg, and an outermost prepreg. In addition, in manufacturing the shaft according to the embodiment of the present invention, a prepreg having a resin content of 20 mass % or less is not used. Each of the above-mentioned prepregs will be described in detail below. In addition, the fiber orientation angle is specified in the description of each prepreg, and this orientation angle is determined based on the axis of the shaft. In other words, the axis of the shaft is set to 0°.

[0016] The first prepreg is 20g / m 2 More than 100g / m 2The first prepreg contains the first fibers in the following range. 2 More than 90g / m 2 It is preferable that the first fibers are contained within the following range: 20 g / m 2 More than 80g / m 2 It is more preferable that the first fibers are contained within the following range: 20 g / m 2 More than 70g / m 2 It is more preferable that the first fibers are contained within the following range: 20 g / m 2 More than 60g / m 2 It is more preferable that the first fibers are contained within the following range: 20 g / m 2 More than 50g / m 2 It is more preferable that the first fibers are contained within the following range: 20 g / m 2 More than 40g / m 2 It is particularly preferable that the first fibers are contained within the following range. The first fibers are preferably carbon fibers. The first prepreg also contains a resin such as an epoxy resin, but the resin may be a resin that has been used in the past. The first prepreg is wound continuously for two or more turns so that the orientation angle of the first fibers is within a range of 80° to 100°. The orientation angle is preferably within a range of 85° to 95°. The first prepreg is preferably a uni-directional prepreg, that is, a prepreg in which the first fibers are aligned in one direction.

[0017] The second prepreg includes a second fiber. The second fiber is preferably a carbon fiber. The second prepreg also includes a resin such as an epoxy resin, but the resin may be a resin that has been used in the past. The second fiber has a fiber elastic modulus in the range of 350 GPa to 800 GPa. The fiber elastic modulus depends on the performance of the target shaft, but is preferably in the range of 350 GPa to 800 GPa, more preferably in the range of 350 GPa to 700 GPa, even more preferably in the range of 350 GPa to 600 GPa, and particularly preferably in the range of 350 GPa to 500 GPa. The second fiber has a fiber breaking elongation in the range of 0.7% to less than 1.5%, more preferably in the range of 0.8% to less than 1.5%, even more preferably in the range of 1.0% to less than 1.5%, and particularly preferably in the range of 1.2% to less than 1.5%. The second prepreg is wound adjacent to the first prepreg on the outside thereof so that the orientation angle of the second fibers is within a range of ±30° to ±40°. In order to suppress a decrease in flex, the orientation angle is preferably within a range of ±30° to ±35°, and in order to suppress a decrease in torque, the orientation angle is preferably within a range of ±35° to ±40°. In addition, the second prepreg is preferably a uni-directional prepreg, that is, a prepreg in which the second fibers are aligned in one direction.

[0018] The outermost prepreg includes a third fiber. The third fiber is preferably a carbon fiber, and more preferably a PAN-based carbon fiber. The outermost prepreg also includes a resin such as an epoxy resin, but the resin may be a resin that has been used in the past. The third fiber has a fiber breaking elongation in the range of 1.5% to 3.0%. The fiber breaking elongation is preferably in the range of 1.8% to 3.0%, more preferably in the range of 2.0% to 3.0%, even more preferably in the range of 2.1% to 3.0%, even more preferably in the range of 2.2% to 3.0%, and particularly preferably in the range of 2.5% to 3.0%. The third fiber has a fiber elastic modulus in the range of 230 GPa to less than 350 GPa, more preferably in the range of 290 GPa to 350 GPa, and even more preferably in the range of 320 GPa to 350 GPa. This outermost prepreg is wound on the outside of the second prepreg so that the orientation angle of the third fibers is within a range of -5° to 5°. The outermost prepreg may be a UD prepreg (Uni-Directional prepreg, a prepreg in which carbon fibers are aligned in one direction) or a woven prepreg. When the outermost prepreg is a woven prepreg, the orientation angle of the fibers perpendicular to the third fibers is within a range of 85° to 95°.

[0019] In addition, in the shaft according to the embodiment of the present invention, the outermost prepreg may be given a decorative finish such as painting or a wrapping film, or a decorative layer made of at least one of a woven fabric and a unidirectional fiber sheet may be formed on the outermost prepreg.

[0020] The above-described prepreg laminated structure makes it possible to distribute the apparent stiffness in the longitudinal direction while maintaining good torque performance of the shaft, and in turn makes it possible to produce a shaft that is lightweight, has high initial stiffness, and exhibits good durability. EXAMPLES

[0021] 1. Making the carbon shaft Carbon fiber with elasticity of 294GPa is used at 25g / m 2 The first UD prepreg (Uni-Directional prepreg, a prepreg in which carbon fibers are aligned in one direction) containing the carbon fibers was wound around a metal mandrel two times in succession so that the orientation angle of the carbon fibers was 90°. The orientation angle here refers to the angle that the carbon fibers make with respect to the axis of the mandrel, and ultimately becomes the angle with respect to the axis of the shaft. Next, carbon fibers exhibiting elasticity of 475 GPa and elongation at break of 0.8% were wound at 75 g / m 2 The second UD prepreg was then wrapped around the top of the first UD prepreg twice, with the carbon fiber orientation angle alternately at +35° / -35°. Then, 125 g / m2 of carbon fiber having an elasticity of 377 GPa and a breaking elongation of 1.2% was wound around the top of the first UD prepreg. 2 The third UD prepreg containing 100 g / m2 of carbon fiber exhibiting an elasticity of 377 GPa and an elongation at break of 1.2% was wound once around the upper side of the second UD prepreg so that the orientation angle of the carbon fiber was 0°. 2 The fourth UD prepreg containing 125 g / m2 of carbon fiber exhibiting an elasticity of 294 GPa and an elongation at break of 2.0% was then wound around the fourth UD prepreg so that the orientation angle of the carbon fiber was 0°. 2 The fifth UD prepreg (corresponding to the "outermost prepreg" in claim 2 of the claims) containing the above-mentioned carbon fibers was wound around the upper side of the fourth UD prepreg one turn at a time so that the orientation angle of the carbon fibers was 0°. Then, as a decorative layer, a carbon fiber fabric made of carbon fibers exhibiting an elasticity of 230 GPa was wound around the upper side of the fifth prepreg one turn so that the orientation angle of the carbon fibers in the carbon fiber fabric was 0° / 90°, and the laminated prepreg was vacuum sealed with a bagging film. The laminated prepreg in this state was cured in an autoclave to obtain the desired carbon shaft. The resin constituting each prepreg was the same type of epoxy resin cured at 130°C. The length of this carbon shaft was 1170 mm.

[0022] 2. Measurement of the physical properties of carbon shafts (1) Mass measurement The mass of the above-mentioned carbon shaft was measured using a weighing machine and was found to be 48.5 g.

[0023] (2) Flex measurement The flex of the above carbon shaft was measured using an Auditor Golf Shaft Profiler in accordance with golf standards, and the flex of the carbon shaft was 15.3 kg.

[0024] (3) Torque measurement When the torque of the above carbon shaft was measured using an Auditor Digital Shaft Torque Meter in accordance with golf standards, the torque of the carbon shaft was 6.7°.

[0025] (4) Durability test A golf club was assembled by attaching a Taylormade M1 460 to the tip of the above-mentioned carbon shaft, and the golf club was attached to a Golf Shot Robo 3DX made by Miyamae Co., Ltd., and the head was hit with a Titleist Pro V1 golf ball made by Acushnet Co., Ltd. at a head speed of 44 m / s by heel-hitting 1,800 times using the Golf Shot Robo 3DX. After that, the entire surface of the carbon shaft was observed with an optical microscope, and no defects including microcracks were found. EXAMPLES

[0026] The target carbon shaft was produced according to the method described in “1. Production of carbon shaft” in Example 1, except that the fifth UD prepreg in Example 1 was replaced with a UD prepreg having carbon fibers exhibiting an elasticity of 324 GPa and an elongation at break of 2.0%, and no decorative layer was provided.

[0027] The various physical properties of the above-mentioned carbon shaft were measured according to the various measuring methods described in "2. Measurement of physical properties of carbon shaft" in Example 1, and the mass was 48.5 g, the flex was 16.9 kg, and the torque was 7.3°. In addition, after hitting a golf ball 1800 times under the same conditions as those shown in Example 1, the entire surface of the shaft was observed under a microscope, and no defects including microcracks were found on the entire surface of the shaft. EXAMPLES

[0028] A target carbon shaft was produced according to the method described in “1. Production of carbon shaft” in Example 1, except that the third UD prepreg and the fourth UD prepreg in Example 1 were replaced with prepregs having carbon fibers exhibiting an elasticity of 294 GPa and an elongation at break of 2.0%.

[0029] The various physical properties of the above-mentioned carbon shaft were measured according to the various measuring methods described in "2. Measurement of physical properties of carbon shaft" in Example 1, and the mass was 47.6 g, the flex was 10.9 kg, and the torque was 6.8°. In addition, after hitting a golf ball 1800 times under the same conditions as those shown in Example 1, the entire surface of the shaft was observed under a microscope, and no defects including microcracks were found on the entire surface of the shaft. EXAMPLES

[0030] The target carbon shaft was produced according to the method described in "1. Production of carbon shaft" in Example 1, except that the decorative layer in Example 1 was replaced with a prepreg having a carbon fiber fabric made of carbon fibers exhibiting an elasticity of 294 GPa and an elongation at break of 2.0%.

[0031] The various physical properties of the above-mentioned carbon shaft were measured according to the various measuring methods described in "2. Measurement of physical properties of carbon shaft" in Example 1, and the mass was 48.8 g, the flex was 15.1 kg, and the torque was 6.8°. In addition, after hitting a golf ball 1800 times under the same conditions as those shown in Example 1, the entire surface of the shaft was observed under a microscope, and no defects including microcracks were found on the entire surface of the shaft. EXAMPLES

[0032] The third UD prepreg in Example 1 was made of 75 g / m2 carbon fiber exhibiting elasticity of 377 GPa and breaking elongation of 1.2%. 2 The fourth and fifth UD prepregs were replaced with prepregs containing 75 g / m2 carbon fiber exhibiting an elasticity of 294 GPa and a breaking elongation of 2.0%. 2 The target carbon shaft was produced according to the method described in "1. Production of carbon shaft" in Example 1, except that the prepreg containing was replaced with a carbon fiber fabric made of carbon fibers exhibiting an elasticity of 294 GPa, and the decorative layer was replaced with a carbon fiber fabric made of carbon fibers exhibiting an elasticity of 294 GPa.

[0033] According to the various measuring methods described in "2. Measurement of physical properties of carbon shaft" in Example 1, various physical properties of the carbon shaft were measured, and the mass was 38.4g, the flex was 10.3kg, and the torque was 8.0°. In addition, a Taylormade M1 460 was attached to the tip of the carbon shaft to assemble a golf club, and the golf club was attached to a Golf Shot Robo 3DX made by Miyamae Co., Ltd., and the head was hit with a Titleist Pro V1 golf ball made by Acushnet Co., Ltd. at a head speed of 38m / s by the Golf Shot Robo 3DX, hitting the heel of the head 1200 times. The entire surface of the carbon shaft was observed with an optical microscope, and no defects including microcracks were confirmed. EXAMPLES

[0034] Carbon fiber with elasticity of 294GPa is used at 25g / m 2The first UD prepreg containing 75 g / m2 of carbon fiber was wound around a metal mandrel twice in succession so that the orientation angle of the carbon fiber was 90°. 2 The second UD prepreg was then wrapped around the top of the first UD prepreg twice, with the carbon fiber orientation angle alternately at +35° / -35°. Then, 150 g / m2 of carbon fiber exhibiting elasticity of 294 GPa and elongation at break of 2.0% was wound around the top of the first UD prepreg. 2 The third UD prepreg containing 150 g / m2 of carbon fiber exhibiting an elasticity of 294 GPaGPa and a breaking elongation of 2.0% was wound once around the upper side of the second UD prepreg so that the orientation angle of the carbon fiber was 0°. 2 The fourth UD prepreg containing 125 g / m2 of carbon fiber exhibiting an elasticity of 294 GPa and an elongation at break of 2.0% was then wound around the fourth UD prepreg so that the orientation angle of the carbon fiber was 0°. 2 The fifth UD prepreg (corresponding to the "outermost prepreg" in claim 2 of the claims) containing the above-mentioned carbon fibers was wound around the upper side of the fourth UD prepreg one turn at a time so that the orientation angle of the carbon fibers was 0°. Then, as a decorative layer, a carbon fiber fabric made of carbon fibers exhibiting an elasticity of 294 GPa was wound around the upper side of the fifth prepreg one turn so that the orientation angle of the carbon fibers in the carbon fiber fabric was 0° / 90°, and the laminated prepreg was vacuum sealed with a bagging film. The laminated prepreg in this state was cured in an autoclave to obtain the desired carbon shaft. The resin constituting each prepreg was the same type of epoxy resin cured at 130°C. The length of this carbon shaft was 1170 mm.

[0035] According to the various measuring methods described in "2. Measurement of physical properties of carbon shaft" in Example 1, various physical properties of the carbon shaft were measured, and the mass was 60.0 g, the flex was 19.0 kg, and the torque was 5.3°. In addition, a Taylormade M1 460 was attached to the tip of the carbon shaft to assemble a golf club, and the golf club was attached to a Golf Shot Robo 3DX made by Miyamae Co., Ltd., and the head was hit with a Titleist Pro V1 golf ball made by Acushnet Co., Ltd. at a head speed of 46 m / s by the Golf Shot Robo 3DX, hitting the heel of the head 1800 times. The entire surface of the carbon shaft was observed with an optical microscope, and no defects including microcracks were confirmed.

[0036] Comparative Example 1 The target carbon shaft was produced according to the method described in “1. Production of carbon shaft” in Example 1, except that the first prepreg in Example 3 was wound around the mandrel once, and after winding the second prepreg, the first prepreg was again wound around the mandrel once.

[0037] The various physical properties of the carbon shaft were measured according to the various measuring methods described in "2. Measurement of physical properties of carbon shaft" in Example 1, and the weight was 47.7 g, the flex was 11.1 kg, and the torque was 6.9°. In addition, when golf balls were continuously hit under the same conditions as those shown in Example 1, the shaft broke before the number of hits reached 1800.

[0038] Comparative Example 2 A target carbon shaft was produced in accordance with the method described in “1. Production of carbon shaft” in Example 1, except that the third UD prepreg, the fourth UD prepreg and the fifth UD prepreg in Example 1 were replaced with UD prepregs having carbon fibers exhibiting an elasticity of 377 GPa and an elongation at break of 1.2%.

[0039] The various physical properties of the carbon shaft were measured according to the various measuring methods described in "2. Measurement of physical properties of carbon shaft" in Example 1, and the weight was 48.8 g, the flex was 15.7 kg, and the torque was 6.7°. In addition, when golf balls were continuously hit under the same conditions as those shown in Example 1, the shaft broke before the number of hits reached 1800. [Industrial Applicability]

[0040] The golf club shaft according to the present invention is lightweight, but exhibits good durability and is capable of suppressing a decrease in flex, thereby making it possible for the user to achieve a greater distance in hitting the ball.

Claims

1. A first prepreg including first fibers in the range of 20 g / m2 to 100 g / m2, the first fibers being wound continuously for two or more turns so that the orientation angle of the first fibers is in the range of 80° to 100°; A second prepreg includes second fibers having a fiber elastic modulus in the range of 350 GPa to 800 GPa, and is wound adjacent to the first prepreg on the outside of the first prepreg so that the orientation angle of the second fibers is in the range of ±30° to ±40°; an outermost prepreg including third fibers having a fiber breaking elongation in the range of 1.5% to 3.0%, the outermost prepreg being wound on the outside of the second prepreg such that the orientation angle of the third fibers is in the range of -5° to 5°; It is formed by stacking Golf club shaft.

2. The device further comprises a decorative layer comprising at least one of a woven fabric and a unidirectional fiber sheet.

2. The shaft for a golf club according to claim 1.

3. Having a mass within the range of 30 g or more and 60 g or less, It indicates a flex in the range of 8kg to 20kg. When the head is attached to the tip side and hits a golf ball with a head speed of 38 m / s, the durability is 1200 or more when the head is less than 45 g, and when the head is attached to the tip side and hits a golf ball with a head speed of 44 m / s, the durability is 1800 or more when the head is attached to the tip side and hits a golf ball with a head speed of 44 m / s.

3. A shaft for a golf club according to claim 1 or 2.