JP2004313781A - Fiber reinforced resin golf shaft and golf club - Google Patents

Abstract

[PROBLEMS] To maintain the ease of swinging up to the ball impact in a golf shaft, and without affecting the appearance of the golf shaft, the bending feeling and strength at the time of swinging, and the vibrations transmitted to the hand. To reduce discomfort.
A shaft includes a front end portion to which a head is attached, a rear end portion to which a grip is attached, and a central portion between the front end portion and the rear end portion. The outer diameter of the shaft gradually increases gradually from the front end to the rear end of the shaft, and the shaft has a tapered shape. The shaft includes a first portion having a substantially constant linear density and a second portion other than the first portion. The first portion is present in an amount of 30% or more of the entire length of the shaft, and the linear density of the first portion is equal to that of the second portion. Greater than density.
[Selection] Figure 12

Description

  The present invention relates to a golf shaft made of fiber reinforced resin (hereinafter referred to as FRP), and more specifically, it is possible to realize a golf club that is less uncomfortable with respect to vibration after hitting and is easy to swing. The present invention relates to a golf shaft and a golf club equipped with the golf shaft.

  The golf shaft is generally made of FRP using carbon fibers as reinforcing fibers. Examples of the method for producing an FRP golf shaft include a known sheet winding method and filament winding method, as well as a braiding method.

  In the sheet winding manufacturing method, a sheet-like prepreg formed by impregnating synthetic resin into parallel rovings is cut into a predetermined shape, and the prepreg is laminated on a mandrel so as to have designed characteristics. After curing, an FRP golf shaft is formed by extracting the mandrel. In the golf shaft formed by this manufacturing method, in order to realize the performance designed for the golf shaft, the performance of the prepreg, the orientation angle of the prepreg with respect to the shaft axis, and the thickness are designed. It is disposed over the entire length of the golf shaft.

  At this time, the thickness of the shaft cross section, that is, the number of prepregs, is made constant so that there is no anisotropy in the cross-sectional radial direction. In some cases, reinforcement may be partially applied to the front end portion on which the head is mounted and the rear end portion on the grip side. Therefore, except for the reinforced front end portion and rear end portion, the shaft is substantially equal in thickness, and the outer diameter of the golf shaft increases monotonically from the front end to the rear end. The linear density distribution along the direction increases almost monotonically from the front end to the rear end.

  In the filament winding manufacturing method, a fiber filament is wound around a mandrel for forming a shaft to form a shaft. When winding, the winding angle of the filament with respect to the shaft axis can be adjusted.

  In the braiding method, a shaft is formed by braiding a tow prepreg formed by impregnating a fiber tow with a resin. Golf shafts (brading shafts) produced by this method have been found in recent years, have a high degree of freedom in design of bending stiffness distribution and linear density distribution, and have good expression in both bending strength and torsion strength. .

Under these circumstances, in order to improve the ease of swinging, several patent applications have been filed that describe changing the linear density distribution relative to the normal linear density distribution of the shaft.
For example, Patent Document 1 discloses a shaft to which a mass body made of a balance weight is added. Patent Document 2 discloses a shaft that is given a partial bulge by abruptly changing the outer diameter and inner diameter of the shaft. Both publications aim at concentrating the linear density substantially at the center other than the front end and the rear end of the golf shaft.

  However, the above-described golf shaft has a great adverse effect on the appearance, bending feeling, and strength. That is, in the golf shaft in which the mass body described in Patent Document 1 is partially added, stress is concentrated at the joint between the mass body and the shaft during a swing, which causes a decrease in strength. In addition, the bending condition becomes distorted at the part to which the mass body is added.

  Moreover, in the golf shaft to which the partial bulge described in Patent Document 2 is given, the bending condition becomes distorted according to the amount of change in shape (secondary moment of cross section). In addition, the appearance is uncomfortable. Therefore, although it may be said that the prior art golf shaft is a golf shaft having an ideal mass distribution in theory, the appearance, the feeling of bending in the actual swing, durability, and ease of manufacture are considered. It ’s not satisfactory.

  Therefore, as described in Patent Document 3, with respect to the linear density of the shaft, a portion of 0.322 to 0.605 meters from the upper end of the grip (the club length is about 48% of the club length from the upper end of the grip). (30% range) with a line density of 20% higher than the other parts, and by introducing optimum club mass distribution conditions while considering the club length, improving the ease of swinging A golf club has been proposed that can increase the hit distance by a small amount of work.

  Further, as described in Patent Document 4, the inclination of the taper of the inner diameter is made smaller than the inclination of the taper of the outer diameter of the shaft, so that the linear density is substantially at the center other than the front and rear ends of the golf shaft. By concentrating the golf ball, a golf shaft capable of obtaining an optimum mass distribution without adversely affecting the appearance of the golf shaft and the bending feeling and strength at the time of swing has been proposed.

  Further, as described in Patent Document 5, in the braiding shaft, the orientation angle of the braided yarn of the braided layer with respect to the longitudinal axis of the shaft is appropriately changed according to the position of the longitudinal axis of the golf shaft. There has been proposed a golf shaft in which the linear density is generally concentrated at the central portion other than the front end portion and the rear end portion.

  Any change in the linear density distribution of the shaft to improve the ease of swinging is to concentrate the linear density at the substantially central portion of the golf shaft, and according to the three inventions described in Patent Documents 3 to 5. A golf shaft with an optimal mass distribution that satisfies the ease of swinging to the impact of hitting the ball and pursues ease of swinging without adversely affecting the appearance of the golf shaft, the bending feeling and strength at the time of swing. Is provided.

  However, there is a problem that such a golf shaft may be somewhat uncomfortable due to a hit feeling generated when it is hit off-center or when it is duffed (when the ball is hit) or vibrations transmitted to the hand. is there.

As the vibration mode after the impact, the mode in which the head and the grip become vibration nodes, and the mode in which the tip side is slightly anti-vibration from near the center of the shaft is dominant. In particular, in a shaft having a structure in which the mass becomes heavy just at the antinode of vibration, the vibration tends to be amplified, which is one of the causes of uncomfortable feeling.
Japanese Patent Laid-Open No. 7-163689 (paragraph number 0017, FIG. 3) Japanese Patent No. 2622428 (2 pages, FIG. 2) JP 2001-170232 A (paragraph number 0037, FIG. 3) Japanese Patent Laid-Open No. 2001-212273 (paragraph number 0010, FIG. 2) JP 2001-276288 A

  The object of the present invention is to maintain the ease of swinging until the ball impact, and also to give a sense of incongruity due to hit feeling and vibration transmitted to the hand without adversely affecting the appearance of the golf shaft, the bending feeling and strength at the time of swing. It is to provide a golf shaft with a small amount.

  In order to solve the above-mentioned problems, according to the invention of claim 1, a front end portion to which the head is mounted and reinforced, a rear end portion to which the grip is mounted, and a center between the front end portion and the rear end portion And a fiber reinforced resin golf shaft having a tapered shape in which the outer diameter of the shaft gradually increases gradually from the front end to the rear end of the shaft. The golf shaft includes a first portion having a substantially constant linear density and a second portion other than the first portion, and the first portion is present at 30% or more of the entire length of the shaft, and the linear density of the first portion is the second. It is set larger than the linear density of the part.

According to a second aspect of the present invention, in the golf shaft according to the first aspect, the first portion exists from a central portion to a rear end.
According to a third aspect of the present invention, in the golf shaft according to the first aspect, the first portion extends from the central portion to the rear end.

  According to a fourth aspect of the present invention, there is provided a front end portion to which the head is mounted and reinforced, a rear end portion to which the grip is mounted, and a central portion between the front end portion and the rear end portion, and the outer diameter of the shaft is the front end. A golf shaft made of fiber reinforced resin having a taper shape that gradually increases from the rear end to the rear end, and the linear density of the remaining portion excluding approximately 30% of the total length of the shaft from the front end of the shaft is the gist. .

  The invention of claim 5 comprises a front end portion to which the head is attached and reinforced, a rear end portion to which the grip is attached, and a central portion between the front end portion and the rear end portion, and the outer diameter of the shaft is In a fiber reinforced resin golf shaft having a tapered shape that gradually increases gradually from the front end to the rear end of the shaft, the gist thereof is that the linear density is substantially constant over the entire length of the shaft.

According to a sixth aspect of the present invention, in the golf shaft according to the first aspect, when the first portion approximates the linear density data to the linear expression f (x) = ax + b by the least square method, the inclination a
a ≦ ± 0.000010 [(kg / m) / mm]
The difference is that the deviation of the line density data from the approximate straight line data is within ± 0.002 (kg / m).

  According to a seventh aspect of the present invention, in the golf shaft according to the first aspect, the golf shaft includes a prepreg sheet and a braided layer disposed on the prepreg sheet, and the minimum value of the linear density distribution in the prepreg sheet is small. This is because the orientation angle of the braid of the braid layer is increased at the existing position.

  The invention according to claim 8 is the golf shaft according to claim 1, wherein the golf shaft has a braid layer made of braided yarns, and the taper ratio of the inner diameter of the braid layer is 0.007 to 0.010. If the length of the first portion where the linear density of the shaft is substantially constant is x (mm), the pair angle with respect to the distance from the shaft tip in the first portion changes linearly, and the first portion The difference Δθ (°) in the set angle obtained by subtracting the set angle of the braid at the end on the shaft front end from the set angle of the set yarn at the end on the rear end side of the shaft from −0.03x to −0.05x Range.

  The invention according to claim 9 is the golf shaft according to claim 1, wherein the golf shaft has a braided layer made of braided yarn, and the taper ratio of the inner diameter of the braided layer is 0.004 to 0.006. If the length of the first portion where the linear density of the shaft is substantially constant is x (mm), the pair angle with respect to the distance from the shaft tip in the first portion changes linearly, and the first portion The difference Δθ (°) in the set angle obtained by subtracting the set angle of the braid at the end on the shaft front end from the set angle of the set yarn at the end on the rear end side of the shaft from −0.01x to −0.03x Range.

  The invention of claim 10 includes a front end portion including a front end, a rear end portion including a rear end, and a central portion between the front end portion and the rear end portion, and a golf shaft made of fiber reinforced resin, and the shaft thereof In a golf club having a head attached to the front end of the shaft and a grip attached to the rear end of the shaft, the shaft has an outer diameter that gradually increases from the front end to the rear end, and has a linear density The first portion is substantially constant and the other second portion, the first portion is present at 30% or more of the entire length of the shaft, and the linear density of the first portion is larger than the linear density of the second portion. The gist is a golf club.

According to an eleventh aspect of the present invention, in the golf club according to the tenth aspect, the first portion exists from the central portion to the rear end of the shaft.
According to a twelfth aspect of the present invention, in the golf club according to the tenth aspect, the first portion extends from the central portion to the rear end of the shaft.

  The invention of claim 13 includes a front end portion including a front end, a rear end portion including a rear end, and a central portion between the front end portion and the rear end portion, and a golf shaft made of fiber reinforced resin, and the shaft thereof In a golf club having a head attached to the front end of the shaft and a grip attached to the rear end of the shaft, the linear density of the remaining portion excluding approximately 30% of the total length of the shaft from the front end of the shaft is substantially constant. The gist of a golf club.

  The invention of claim 14 is provided with a front end portion including a front end, a rear end portion including a rear end, and a central portion between the front end portion and the rear end portion, and a golf shaft made of fiber reinforced resin, and the shaft A golf club having a head attached to the front end portion of the golf club and a grip attached to the rear end portion of the shaft has a linear density substantially constant over the entire length of the shaft.

  According to the present invention, while maintaining ease of swinging until the ball impact, and without adversely affecting the appearance of the golf shaft, the bending feeling and strength at the time of swinging, a sense of incongruity due to a hit feeling or vibration transmitted to the hand A golf shaft with less is provided.

Hereinafter, the present invention will be described in detail with reference to the drawings and preferred embodiments of the present invention.
FIG. 1 is a schematic view showing a golf club. The golf club 1 includes a head 2, a shaft 3, and a grip 4. The shaft 3 includes a front end portion 5 to which the head 2 is attached and reinforced, a rear end portion 7 to which the grip 4 is attached, and a central portion 6 between the front end portion 5 and the rear end portion 7. The outer diameter of the shaft 3 generally increases gradually from the front end 8 to the rear end 9.

  Generally, in a plurality of golf clubs constituting a golf club set, when a golfer lifts each golf club, it feels almost the same weight for each club, for example, the specifications of each club, for example, the upper end of the weight and grip The distance from the center of gravity to the club is set. In such a golf club, in order to improve the ease of swinging, as described in detail in Patent Document 3, it is effective to shorten the equivalent single pendulum length of the club. In addition, the magnitude of the moment of inertia of the club with the upper end of the grip as the base affects the sensation of feeling during swing, such as “heavy and light to swing” and “easy to swing”. This is one of the easy parameters to give. Generally, when the moment of inertia is small, the club swings and the club feels light. The present invention focuses on these two parameters, that is, the equivalent single pendulum length of the club and the moment of inertia of the club.

  In the present invention, the equivalent single pendulum length of the club is set at the upper end of the club grip according to the actual swing analysis. The upper end of the grip substantially corresponds to the rear end 9 of the shaft 3.

The equivalent single pendulum length Lp (m) with the upper end of the grip as the rotation axis is the moment of inertia I (kgm ² ) around the upper end of the grip, the distance from the club mass Mc (kg) and the center of gravity G of the club from the upper end of the grip It is a value divided by R (m), and is expressed by the following equation (1).
Lp = I / (Mc · R) (1)
Next, the inertia moment I around the upper end of the club grip was determined from the inertia characteristics of each part of the club.

I = Igh + Igs + Igg + Mh · (R−Lc) ² + Ms · (R−Rs) ² + Mg · (R−Rg) ² + Mc · R ² (2)
In the formula, Mh (kg): head mass Ms (kg): shaft mass Mg (kg): grip mass Mc = Mh + Ms + Mg: club mass (kg)
Lc (m): Club length Rg (m): Distance from the upper end of the grip to the center of gravity of the grip Rs (m): Distance from the grip insertion end (the rear end 9 of the shaft) to the center of gravity of the shaft Igh ( kgm ² ): Moment of inertia of the head around the axis perpendicular to the longitudinal direction of the shaft passing through the center of gravity of the head (inertia moment around the center of gravity of the head)
Igs (kgm ² ): The moment of inertia of the shaft around the axis perpendicular to the longitudinal direction of the shaft passing through the center of gravity of the shaft (the moment of inertia around the center of gravity of the shaft)
Igg (kgm ² ): Inertia moment of grip around an axis perpendicular to the longitudinal direction of the shaft (or longitudinal direction of the grip) passing through the center of gravity of the grip (inertia moment around the center of gravity of the grip)
It is.

The present invention is characterized in that the linear density, which is the mass per unit length in the longitudinal direction of the shaft, is set so as to reduce both of the above two parameters.
The relationship between the linear density along the longitudinal direction of the shaft, the equivalent single pendulum length Lp, and the moment of inertia I was analyzed as follows.

  2 and 3 show the linear density distribution of the shaft in Analysis Example 1-6 of the present invention and the shaft in one comparative analysis example. The shaft mass Ms in Analysis Example 1-6 and Comparative Analysis Example was 0.055 kg. The vertical axis represents the linear density (kg / m), and the horizontal axis represents the position (mm) from the tip of the shaft.

  The shaft of the comparative analysis example shows a typical linear density distribution of the shaft of the sheet winding manufacturing method, and the linear density distribution is directed toward the grip end (rear end) except for the front end portion that is attached to the head and is reinforced. It is increasing monotonously. In other words, the linear density on the head side and grip side is large, and there is a minimum value as characteristic of the sheet winding method.

  Table 1 shows various physical properties of the single shaft of each analysis example. In the comparative analysis example, since the linear density at the front end side and the rear end side is large, the inertia moment of the shaft around the axis perpendicular to the longitudinal direction of the shaft passing through the center of gravity of the shaft (inertia moment around the center of gravity of the shaft) Igs is comparative analysis. You can see that it is the largest in the example.

表２は、各解析例でのヘッド質量Ｍｈを０．１９４±０．００１（ｋｇ），グリップ質量Ｍｇを０．０４５ｋｇ，クラブ長さＬｃを４５インチ（１１４３ｍｍ），Ｍｃ・ Ｒ＝０．２５９ｋｇｍとした時のグリップの上端回りの慣性モーメントＩと相当単振子長Ｌｐを示す。

Table 2 shows that the head mass Mh in each analysis example is 0.194 ± 0.001 (kg), the grip mass Mg is 0.045 kg, the club length Lc is 45 inches (1143 mm), Mc · R = 0.259 kgm Is the moment of inertia I around the upper end of the grip and the equivalent simple pendulum length Lp.

  The values of the moment of inertia I and the equivalent simple pendulum length Lp in Analysis Example 1-6 of the present invention are both smaller than those in the comparative analysis example.

以上の解析から、グリップ上端回りの慣性モーメントＩとシャフトの相当単振子長Ｌｐをいずれも小さくするには、シャフトの線密度が、シャフト全長の一定範囲にわたって、特に後端側において、略一定となるようにシャフトを構成すればよいことがわかる。

From the above analysis, in order to reduce both the moment of inertia I around the upper end of the grip and the equivalent simple pendulum length Lp of the shaft, the linear density of the shaft is substantially constant over a certain range of the entire length of the shaft, particularly on the rear end side. It can be seen that the shaft should be configured as follows.

  The portion where the linear density of the shaft is substantially constant needs to be 30% or more of the total length of the shaft (analysis examples 1-4, 5 and 6). More preferably, the substantially constant portion is present at 30% or more of the entire shaft length from the central portion to the rear end (all analysis examples 1-4, 5, and 6). More preferably, the substantially constant portion extends from the central portion to the rear end (analysis examples 1, 2, 5, and 6).

  In another aspect, the portion where the linear density of the shaft is substantially constant extends over a portion excluding approximately 30% of the entire shaft length from the tip (analysis examples 5 and 6). More preferably, the substantially constant portion is substantially the entire length of the shaft (analysis example 5).

  Usually, the shaft can be manufactured by a sheet winding method alone. However, in order to construct a linear density distribution shaft according to the present invention in the sheet winding method, the shaft does not become an integer at any position in the longitudinal direction, that is, it does not cover the entire circumference of the shaft, or the number of laminations is partially The hardness varies in the circumferential direction of the shaft. This is likely to affect the quality of the shaft itself. For this reason, the braiding method, the filament winding method, and the manufacturing method combining the sheet winding method and the braiding method are preferable, except for the sheet winding method alone.

The following summarizes the ideas in the combined manufacturing method of the sheet winding method and the braiding method.
In the portion manufactured by the sheet winding method, as shown in the comparative analysis examples of FIGS. 2 and 3, the minimum value of the linear density distribution of the shaft exists within the range of about 100 to 400 mm where the reinforcing portion at the tip does not exist. . That is, the characteristic of the linear density distribution decreases from the front end of the shaft to the position of the minimum value, and generally increases monotonically from the position of the minimum value to the rear end of the shaft. Therefore, it is necessary to add mass to the portion where the minimum value exists.

Therefore, in the part produced by the braiding method, the braid angle of the braiding method is increased as much as possible around the position where the above-mentioned minimum value exists, and the overlap between the fiber bundles is increased, thereby making the braided layer The thickness of the fiber bundle is set so as to increase, the assembly angle is reduced toward the grip side, and the overlap between the fiber bundles is reduced. The ratio of reducing the set angle is as follows.
-When the taper ratio (described later) of the inner diameter of the braided layer is relatively large, such as about 0.007 to 0.010, the length of the first portion that makes the linear density of the shaft substantially constant is x (mm). The braiding angle with respect to the distance from the shaft front end at the first portion is linearly changed, and the braiding yarn at the end on the shaft front end side from the braiding angle of the first portion at the rear end side of the shaft. The set angle difference Δθ (°) obtained by subtracting the set angle may be set in a range from −0.03x to −0.05x.

That is, in the state where the taper ratio is applied, in the case where the first portion that makes the linear density of the shaft substantially constant is 1000 mm, −0.03 × 1000 = −30 (°) and −0.05 × 1000 Based on the calculation of = −50 °, the difference Δθ (°) between the set angles may be set in the range of −30 ° to −50 °. Further, when the portion where the linear density of the shaft is substantially constant is set to 800 mm, the difference Δθ in the set angle may be set in the range of −24 ° to −40 ° based on the same calculation.
・ When the taper ratio of the inner diameter of the braided layer is relatively small, about 0.004 to 0.006, the length of the portion where the linear density of the shaft is substantially constant is x (mm). The set angle of the set angle is obtained by linearly changing the set angle with respect to the distance from the shaft tip and subtracting the set angle of the set yarn at the end on the shaft front end from the set angle of the set yarn at the end on the rear end side of the shaft of the portion. The difference Δθ (°) may be set in a range from −0.01x to −0.03x.

  That is, when the portion where the linear density of the shaft is substantially constant is set to 1000 mm, the set angle difference Δθ may be set to −10 ° to −30 °. When the portion where the linear density of the shaft is substantially constant is set to 800 mm, the set angle difference Δθ may be set in the range of −8 ° to −24 °.

  The taper ratio of the inner diameter of the braided layer, that is, the taper of the outer diameter of the mandrel (when the braided layer is wound directly on the mandrel) or the shaft (when there is a sheet on the mandrel) before braiding the braided layer The ratio δ is the outer diameter of the mandrel or shaft at the first position along the longitudinal axis of the shaft, d1 (mm), and the outer diameter of the mandrel or shaft at the second position on the tip side of the shaft from the first position. Is a value represented by δ = (d1−d2) / Δ, where d2 (mm) (d1> d2) and the distance between the first position and the second position is Δ (mm). .

When the sheet winding method and the braiding method were combined, a method for making the linear density distribution of the shaft almost constant was sought.
FIG. 4 shows the linear density distribution of the sheet portion from the front end to the rear end of 20 types of shafts. The used mandrel has an outer diameter of 14.0 mm at a position (first position) 1000 mm from the tip (second position), and the outer diameter taper ratio (taper diameter of the shaft inner diameter) is 0.004, 0.00 mm, respectively. 005, 0.006, 0.007, and 0.008. The thickness increment Δt of the shaft sheet portion was 0.25 mm, 0.50 mm, 0.75 mm, and 1.00 mm over the entire length. It can be seen that the linear density distribution increases almost linearly and monotonically as the mandrel diameter increases from the front end to the rear end.

FIG. 5 shows the linear density distribution of the braided layer from the front end to the rear end of 15 types of shafts. The outer diameter of the mandrel and the taper ratio of the outer diameter (shaft ratio of the shaft inner diameter) were the same as in the example of FIG.
As a braided layer, UT500 (trade name of Toho Tenax Co., Ltd., 12,000 single fibers converged on yarn, fiber fineness of 1230 g / km, resin content about 35%) A total of 16 yarns were used, 8 for each of the left and right braids.

  The braiding angle between the leading end and the trailing end of the braiding yarn (1000 mm from the leading end) can be from 50 ° to 10 °, 50 ° to 30 °, or 30 ° to 10 °, from the shaft tip, for several examples. Each pair angle with respect to the distance was changed to be linear. That is, the difference Δθ in the combination angle obtained by subtracting the combination angle of the combination yarn at the tip from the combination angle of the combination yarn at the rear end is, for example, 10 in the example in which the combination angle is changed from 10 ° at the rear end to 50 ° at the front end. -50 ° = -40 °. In the example of 30 ° to 50 °, the set angle difference Δθ is −20 °, and in the example of 10 ° to 30 °, the set angle difference Δθ is −20 °. It can be seen that, unlike the shaft of FIG. 4, the linear density distribution decreases as the mandrel diameter increases from the tip (tip) to the rear end (butt).

6 is a linear density distribution when the linear density of the sheet portion of FIG. 4 and the linear density of the braided layer of FIG. 5 (a diagram of the linear density distribution when the braiding angle is changed) are simply added. . In some cases, there is an example in which the linear density distribution decreases toward the rear end side, but in almost all examples, the portion from the tip to 1000 mm, or 30% or more (about 300 mm or more) of the entire shaft length. Until the linear density distribution is constant, that is, the slope a when the linear density data is approximated to the linear expression f (x) = ax + b by the least square method,
a ≦ ± 0.000010 [(kg / m) / mm]
It turns out that it is.

From the above consideration, the following facts were found.
-At least one of the case where the taper ratio of the inner diameter of the braided layer is relatively large such as 0.007 and 0.008 and the case where the thickness increment of the sheet portion is relatively large such as 0.75 mm and 1.00 mm In this case, the linear density distribution may be made constant as follows. That is, when the length of the first portion that makes the linear density of the shaft substantially constant is x (mm), the set angle with respect to the distance from the shaft tip in the first portion is changed linearly, and the first portion The difference Δθ (°) in the set angle obtained by subtracting the set angle of the braid at the end on the shaft front end from the set angle of the set yarn at the end on the rear end side of the shaft from −0.03x to −0.05x Should be in the range.
・ When the taper ratio of the inner diameter of the braided layer is relatively small as 0.004, 0.005, and 0.006, and when the thickness increase of the sheet portion is relatively small as 0.25 mm and 0.50 mm In at least one of the cases, the linear density distribution may be made constant as follows. That is, when the length of the first portion that makes the linear density of the shaft substantially constant is x (mm), the set angle with respect to the distance from the shaft tip in the first portion is changed linearly, and the first portion The difference Δθ (°) in the set angle obtained by subtracting the set angle of the braid at the end on the shaft front end from the set angle of the set yarn at the end on the rear end side of the shaft from −0.01x to −0.03x Should be in the range.

A specific example of a shaft manufactured only by the braiding manufacturing method and a shaft manufactured by a combination of the sheet winding manufacturing method and the braiding manufacturing method is shown.
Mandrel to be used: length 1450mm, diameter 4.00mmφ on the small diameter side, diameter 13.65mmφ on the large diameter side (or 14.00mmφ)
Braiding yarn to be used: The following roving yarn consisting of a carbon fiber bundle preliminarily impregnated with a one-component modified epoxy resin (1) UT500-12K (trade name of roving yarn from Nippon Oil Co., Ltd.) The number of single fibers is 12,000, the fineness of the fibers is 1230 g / km, the resin content is about 35%, and the tensile modulus is 240 GPa.
(2) T700-6K (trade name of roving yarn of Toray Industries, Inc.) The number of converged single fibers is 6000, the fineness of the fibers is 615 g / km, the resin content is about 35%, and the tensile elastic modulus is 240 GPa.
(3) M40J-12K (trade name of roving yarn of Toray Industries, Inc.) The number of converged single fibers is 12,000, the fineness of the fibers is 692 g / km, the resin content is about 35%, and the tensile elastic modulus is 400 GPa.

  The reinforcing fiber in the sheet portion was carbon fiber. A prepreg sheet (resin content Rc = 20 to 30%, wall thickness 0.05 to 0.2 mm) having a tensile elastic modulus of 240 GPa, 300 GPa, 400 GPa, and 460 GPa and made of a semi-cured carbon fiber impregnated with an epoxy resin. Thick ones) were used. The hoop sheet in which the reinforcing fibers are wound in the circumferential direction has a thickness of about 0.05 to 0.10 mm in consideration of workability and the like.

  FIG. 7 is a schematic diagram for explaining a manufacturing method of an embodiment of a shaft manufactured by a braiding manufacturing method. The rod-like member M in FIG. 7 is a mandrel used for manufacturing a shaft. The right side of the figure corresponds to the small-diameter side end portion (shaft tip side) of the mandrel, and the left side is the large-diameter side end portion (shaft rear end Side). The shaft of this example is almost the same as the shaft of the analysis example 5 of the present invention described above.

  The shaft manufactured by the manufacturing method of FIG. 7 has four braid layers. Of the four braided layers, the first inner layer close to the mandrel M is composed of eight left and right braided yarns (M40J-12K) having symmetrical orientation angles with respect to the longitudinal axis of the shaft, as shown in FIG. Thus, the orientation angle of the braid varies from ± 40 ° to ± 50 ° along the longitudinal axis of the shaft from the front end to the rear end of the shaft. The second inner layer is located outside the first inner layer, and is composed of eight left and right braids (UT500-12K) each having an orientation angle symmetrical to the longitudinal axis of the shaft. It is constant at ± 30 ° over the entire length.

  Next, the first outer layer is positioned outside the second inner layer, and eight left and right braids (T700-6K) having an orientation angle symmetrical with respect to the longitudinal axis of the shaft and the longitudinal axis of the shaft. It consists of 8 central yarns (T700-6K) with an orientation angle of + 0 °. The second outer layer is composed of the same braiding yarn as that of the first outer layer, although the orientation angle of the left and right braiding yarns is different from that of the first outer layer.

  The orientation angle of the first outer layer braid is ± 45 ° along the longitudinal axis of the shaft at a position 300 mm from the tip, and ± 10 ° along the longitudinal axis of the shaft at the rear end, ie, 1143 mm from the tip. And Δθ is −35 ° in an interval of about 800 mm.

  The orientation angle of the second outer layer braid is ± 20 ° along the longitudinal axis of the shaft at a position 300 mm from the tip, and ± 10 along the longitudinal axis of the shaft at the rear end, ie, 1143 mm from the tip. And Δθ is −10 ° in an interval of about 800 mm.

By finishing the outermost layer by polishing, a shaft having a desired linear density distribution can be easily finished.
FIG. 8 shows a manufacturing method of an embodiment of a shaft (shaft according to Embodiment 3 of the present invention) finished by a braiding method after winding a reinforcing piece S of a prepreg sheet around a portion of the mandrel M corresponding to the tip of the shaft. FIG. The shaft manufactured by the manufacturing method of FIG. 8 has two prepreg sheets and four assembled layers. The prepreg sheet to be used is two bias sheets wound so that the carbon fibers are inclined with respect to the longitudinal direction of the shaft. Among them, the inclination angle of the fibers of one sheet S is symmetrical with respect to the inclination angle of the fibers of the other sheet and the longitudinal axis of the shaft. The structure of the braid layer arranged on the prepreg sheet is as shown in FIG. The sheet S of FIG. 8 is a bias sheet, but it may be a straight sheet in which the braid is oriented in a direction of 0 ° with respect to the longitudinal axis of the shaft.

The shaft shown in FIG. 8 has four braid layers.
Of the four braided layers, the first inner layer close to the mandrel M is composed of eight left and right braided yarns (M40J-12) having symmetrical orientation angles with respect to the longitudinal axis of the shaft, as shown in FIG. Thus, the orientation angle of the braid varies from ± 40 ° to ± 50 ° along the longitudinal axis of the shaft from the front end to the rear end of the shaft.

  The second inner layer is located on the outside of the first inner layer and is composed of eight left and right braids (T700-6K) each having an orientation angle symmetrical to the longitudinal axis of the shaft. Constant at ± 30 ° over the entire length of the shaft.

  Next, the first outer layer is positioned outside the second inner layer, and eight left and right braids (T700-6K) having an orientation angle symmetrical with respect to the longitudinal axis of the shaft and the longitudinal axis of the shaft. It consists of eight central threads (T700-6K) having an orientation angle of + 0 °. The second outer layer is composed of the same type of braid as the first outer layer, although the orientation angle of the left and right braids is different from that of the first outer layer.

  The orientation angle of the braiding yarn in the first outer layer is ± 45 ° along the longitudinal axis of the shaft at a position 300 mm from the tip, and along the longitudinal axis of the shaft at the rear end (position of 1143 mm from the tip). ± 10 °, and Δθ is −35 ° in an interval of about 800 mm. The orientation angle of the braid in the second outer layer is ± 20 ° along the shaft longitudinal axis at a position 300 mm from the tip, and the shaft longitudinal axis at the rear end (position 1143 mm from the tip). Is ± 10 °, and Δθ is −10 ° in an interval of about 800 mm.

  FIGS. 9 and 10 show examples of shafts wound by prepreg sheets corresponding to a ratio of 20 to 50% of the total mass of the shaft, and then finished by the braiding method (shafts of Examples 1 and 2 of the present invention, respectively). It is the schematic explaining the manufacturing method.

  The shaft manufactured by the manufacturing method of FIG. 9 has two prepreg sheets S and three assembly layers. The inner prepreg sheet is a hoop sheet in which reinforcing fibers are wound in the circumferential direction, and the outer sheet wound around the mandrel M at the shaft tip is a straight sheet in which reinforcing fibers are arranged in parallel with the longitudinal axis of the shaft. The structure of the braid layer arranged on the prepreg sheet is as shown in FIG.

Specifically, the shaft shown in FIG. 9 has three braid layers.
Of the three braided layers, the inner layer close to the inner prepreg sheet is composed of 8 left and right braided yarns (M40J-12K) each having a symmetrical orientation angle with respect to the longitudinal axis of the shaft, as shown in FIG. In addition, the orientation angle of the braid varies from ± 45 ° to ± 50 ° along the longitudinal axis of the shaft from the front end to the rear end of the shaft.

  The first outer layer is located outside the inner layer and has eight right and left braids (T700-6K) having an orientation angle symmetrical to the longitudinal axis of the shaft, and + 0 ° with respect to the longitudinal axis of the shaft. It consists of eight central yarns (T700-6K) having an orientation angle. The second outer layer is composed of the same type and number of braids as the first outer layer, although the orientation angle of the left and right braids is different from that of the first outer layer.

  The orientation angle of the braided yarn in the first outer layer is ± 45 ° along the longitudinal axis of the shaft at a position 300 mm from the front end, and ±± along the longitudinal axis of the shaft at the rear end (position at 1143 mm from the front end). 10 °, and Δθ is −35 ° in an interval of about 800 mm. Further, the orientation angle of the braided yarn in the second outer layer is ± 20 ° along the shaft longitudinal axis at a position 300 mm from the tip, and along the shaft longitudinal axis at the rear end (position 1143 mm from the tip). ± 10 ° and Δθ is −10 ° in a section of about 800 mm.

  The shaft manufactured by the manufacturing method of FIG. 10 has three prepreg sheets S and three assembly layers. The two inner prepreg sheets are bias sheets in which the inclination angles of the fibers of the sheet are symmetrical with respect to the longitudinal axis of the shaft. The outer sheet wound around the mandrel M at the front end of the shaft is a straight sheet in which reinforcing fibers are arranged in parallel with the longitudinal axis of the shaft. The structure of the braid layer arranged on the prepreg sheet is as shown in FIG.

Specifically, the shaft shown in FIG. 10 has three braid layers.
Of the three braided layers, the inner layer close to the inner prepreg sheet is composed of 8 left and right braided yarns (M40J-12K) each having a symmetrical orientation angle with respect to the longitudinal axis of the shaft, as shown in FIG. Further, the braid has an orientation angle of ± 45 ° along the longitudinal axis of the shaft at a position of 300 mm from the tip of the shaft, and ± 10 along the longitudinal axis of the shaft at the rear end (position of 1143 mm from the leading end). The orientation angle is .degree., And .DELTA..theta. Is -35.degree. In a section of about 800 mm from 300 mm to 1143 mm from the tip.

  The first outer layer is located outside the inner layer and has eight right and left braids (T700-6K) having an orientation angle symmetrical to the longitudinal axis of the shaft, and + 0 ° with respect to the longitudinal axis of the shaft. It consists of eight central yarns (T700-6K) having an orientation angle. The second outer layer is composed of the same type and number of braids as the first outer layer, although the orientation angle of the left and right braids is different from that of the first outer layer.

  The orientation angle of the braided yarn in the first outer layer is ± 45 ° along the longitudinal axis of the shaft at a position 300 mm from the front end, and ±± along the longitudinal axis of the shaft at the rear end (position at 1143 mm from the front end). 10 °, and Δθ is −35 ° in an interval of about 800 mm. Further, the orientation angle of the braided yarn in the second outer layer is ± 20 ° along the shaft longitudinal axis at a position 300 mm from the tip, and along the shaft longitudinal axis at the rear end (position 1143 mm from the tip). ± 10 ° and Δθ is −10 ° in a section of about 800 mm.

  FIG. 11 shows a manufacturing method of a shaft example (shaft according to the fourth embodiment of the present invention) finished by a braiding method after winding a prepreg sheet corresponding to a proportion of 50 to 70% of the total mass of the shaft around the mandrel M. It is a schematic diagram to explain. The shaft manufactured by the manufacturing method of FIG. 11 has five prepreg sheets S and two assembled layers. The five prepreg sheets consist of a hoop layer, two bias layers in which the inclination angles of the fibers of the sheet are symmetrical with respect to the longitudinal axis of the shaft, a straight layer, and a straight end portion Is a layer. The structure of the braid layer arranged on the prepreg sheet is as shown in FIG.

Specifically, the shaft shown in FIG. 11 has two braid layers.
Of the two braided layers, the first outer layer is located outside the inner layer of the prepreg sheet and has eight left and right braided yarns (T700-6K) each having an orientation angle symmetrical to the longitudinal axis of the shaft. And eight central threads (T700-6K) having an orientation angle of + 0 ° with respect to the longitudinal axis of the shaft. The second outer layer is composed of the same type and number of braids as the first outer layer, although the orientation angle of the left and right braids is different from that of the first outer layer.

  The orientation angle of the braid in the first outer layer is ± 35 ° along the longitudinal axis of the shaft at a position 300 mm from the tip, and ±± along the longitudinal axis of the shaft at the rear end (position of 1143 mm from the tip). 10 °, and Δθ is −25 ° in an interval of about 800 mm. Further, the orientation angle of the braided yarn in the second outer layer is ± 25 ° along the longitudinal axis of the shaft at a position 300 mm from the tip, and along the longitudinal axis of the shaft at the rear end (position of 1143 mm from the tip). ± 10 ° and Δθ is −15 ° in an interval of about 800 mm.

  FIG. 12 shows the linear density distribution of the shaft of Example 1-4 of the present invention and the linear density distribution of the shafts of Comparative Examples 1 and 2. The vertical axis represents the linear density (kg / m), and the horizontal axis represents the position (mm) from the tip of the shaft. The linear density distribution of the shaft of Example 1-4 changes continuously along the longitudinal axis of the shaft, that is, smoothly. The shaft mass Ms of Example 1-3 and Comparative Example 1 is 0.065 kg, and the shaft mass Ms of Example 4 and Comparative Example 2 is 0.050 kg. The shafts of Comparative Examples 1 and 2 are shafts produced by a sheet winding method.

The first part whose linear density is “substantially constant” is a part in which the slope “a” is expressed by the following expression when linear density data is approximated to the linear expression f (x) = ax + b by the method of least squares. Point.
a ≦ ± 0.000010 [(kg / m) / mm]
The deviation of the linear density data from the approximate straight line data is preferably within ± 0.002 (kg / m).

  If the magnitude of the inclination “a” deviates from the above range, the moment of inertia I and the equivalent simple pendulum length Lp increase, or the desired first moment Mc · R that satisfies the above-described equation (1) is provided. In addition, there is a possibility that the combination of the head, the shaft and the grip cannot be obtained.

  Table 3 shows various physical properties of the shafts of Examples 1-4 and Comparative Examples 1 and 2 of the present invention. It can be seen that the moment of inertia Ig around the center of gravity of the shaft is the largest in Comparative Example 1.

表４は、本発明の実施例１−４と比較例１，２のグリップの上端回りの慣性モーメントＩと相当単振子長Ｌｐを示す。実施例１−３と比較例１については、ヘッド質量Ｍｈを０．１９５±０．００１（ｋｇ），グリップ質量Ｍｇを０．０５０ｋｇ，クラブ長さＬｃを４５インチ（１１４３ｍｍ），Ｍｃ・ Ｒ＝０．２６６ｋｇｍとした。また、実施例４と比較例２については、ヘッド質量Ｍｈを０．１９２（ｋｇ），グリップ質量Ｍｇを０．０４２ｋｇ，クラブ長さＬｃを４５インチ（１１４３ｍｍ），Ｍｃ・ Ｒ＝０．２５５ｋｇｍとした。

Table 4 shows the moment of inertia I around the upper end of the grips of Examples 1-4 and Comparative Examples 1 and 2 of the present invention and the equivalent simple pendulum length Lp. For Example 1-3 and Comparative Example 1, the head mass Mh is 0.195 ± 0.001 (kg), the grip mass Mg is 0.050 kg, the club length Lc is 45 inches (1143 mm), Mc · R = It was 0.266 kgm. For Example 4 and Comparative Example 2, the head mass Mh is 0.192 (kg), the grip mass Mg is 0.042 kg, the club length Lc is 45 inches (1143 mm), and Mc · R = 0.255 kgm. did.

  In all of Examples 1-4 of the present invention, the values of the moment of inertia I and the equivalent simple pendulum length Lp are both smaller than the values in the comparative example.

実施例１，２，３と比較例１のシャフトを備えたクラブの４本の試打評価（表５、テストＡ）及び、実施例４，比較例２のシャフトを備えたクラブの２本の試打評価（表５、テストＢ）を、２名のプロゴルファー及び５名の上級から中級レベルのアマチュアゴルファーによって実施した。評価方法は５段階評価で、比較例１，２のクラブの得点をすべて「３」とし、７名の試打者からの回答の得点の平均を、そのクラブの得点とした。

Four trial hit evaluations of the clubs with the shafts of Examples 1, 2, 3 and Comparative Example 1 (Table 5, Test A) and two trial hits of the clubs with the shafts of Example 4 and Comparative Example 2 The evaluation (Table 5, Test B) was conducted by 2 professional golfers and 5 senior to intermediate level amateur golfers. The evaluation method was a five-level evaluation. The scores of the clubs of Comparative Examples 1 and 2 were all “3”, and the average of the scores of responses from seven test hitters was the score of the club.

  The results are shown in Table 5. It can be seen that most golfers can experience “easy to swing” and “easy timing” in the clubs having the shafts of Examples 1 to 4.

本発明の実施形態のゴルフシャフトによれば以下に表す効果がある。
・シャフトの組物層の組糸の配向角度を、所望の線密度を満たすように変化させている。このため、好適なグリップの上端回りの慣性モーメントＩと相当単振子長Ｌｐを得ることができる。従って、スイングし易さを維持しつつ、ゴルフシャフトの外観、スイング時のしなり感や強度に悪影響を及ぼすことなく、打感や手に伝わる振動による違和感を少なくすることができる。
・シャフトの外径が先端から後端にかけて概ね漸次増加するテーパ形状を有する。このため、シャフトの外観、スイング時のしなり感や強度が良好である。
・シャフトの線密度がシャフトの長手方向軸に沿って連続的に変化している。このため、シャフトにかかる応力が集中することはなく、シャフトの外観、スイング時のしなり感や強度がやはり良好である。

The golf shaft according to the embodiment of the present invention has the following effects.
The orientation angle of the braiding yarn of the shaft braiding layer is changed so as to satisfy a desired linear density. For this reason, a suitable moment of inertia I around the upper end of the grip and an equivalent simple pendulum length Lp can be obtained. Therefore, while maintaining the ease of swinging, it is possible to reduce the sense of incongruity due to the hit feeling and vibration transmitted to the hand without adversely affecting the appearance of the golf shaft, the bending feeling and strength at the time of swing.
The outer diameter of the shaft has a tapered shape that gradually increases gradually from the front end to the rear end. For this reason, the appearance of the shaft, the bending feeling and the strength at the time of swing are good.
-The linear density of the shaft is continuously changing along the longitudinal axis of the shaft. For this reason, the stress applied to the shaft is not concentrated, and the appearance of the shaft, the bending feeling and the strength at the time of swing are still good.

The embodiment of the present invention can be modified as follows, for example.
-It is good also considering the reinforced fiber used for a prepreg sheet or a braided layer as fibers other than a carbon fiber.
-As for the linear density of a shaft, if the part where linear density is substantially constant exists 30% or more of a shaft full length, there may be a discontinuous part.
-The butt portion of the shaft to which the grip is attached may have a certain diameter.
The shaft may be formed by any of a sheet winding method, a filament winding method, and a braiding method in addition to a combination of a sheet winding method and a braiding method.

1 is a schematic diagram showing a golf club. The graph which shows the linear density distribution of the shaft of the analysis example 1-4 of this invention, and the shaft of a comparative analysis example. The graph which shows the linear density distribution of the shaft of the analysis examples 5 and 6 of this invention, and the shaft of a comparative analysis example. The graph which shows the linear density distribution from the front-end | tip of the sheet | seat part of the shaft in the Example of this invention to a rear end. The graph which shows the linear density distribution from the front-end | tip of the assembly layer of the shaft in the Example of this invention to a rear end. The graph which shows the linear density distribution which integrated the linear density distribution shown in FIG. 4, and the linear density distribution shown in FIG. Schematic explaining the manufacturing method of the Example of the shaft manufactured by the braiding manufacturing method. The schematic diagram explaining the manufacturing method of the Example of the shaft finished by the braiding manufacturing method, after winding the reinforcement piece of a prepreg sheet to the part corresponding to the front-end | tip part of the shaft of a mandrel. The schematic diagram explaining the manufacturing method of the Example of the shaft finished by the braiding manufacturing method, after winding the prepreg sheet for the ratio of 20-50% of the total mass of the shaft. FIG. 7 is a schematic diagram for explaining a manufacturing method of another embodiment of the shaft different from that of FIG. 6 after winding a prepreg sheet for a ratio of 20 to 50% of the total mass of the shaft and finishing by a braiding method. The schematic diagram explaining the manufacturing method of the Example of the shaft finished by the braiding manufacturing method after winding the prepreg sheet for the ratio of 50-70% of the total mass of the shaft. The graph which shows the linear density distribution of the shaft of Example 1-4 of this invention, and the linear density distribution of the shaft of the comparative examples 1 and 2. FIG.

Explanation of symbols

2 ... head, 3 ... shaft, 4 ... grip, 5 ... tip, 6 ... center, 7 ... rear end, 8 ... shaft tip, 9 ... shaft rear end.

Claims (14)

Consists of a tip part to which the head is attached, a rear end part to which the grip is attached, and a central part between the tip part and the rear end part, and the outer diameter of the shaft gradually increases gradually from the tip to the rear end of the shaft. In a fiber reinforced resin golf shaft having a tapered shape,
A first portion having a substantially constant linear density and a second portion other than the first portion, wherein the first portion is present at 30% or more of the entire shaft length, and the linear density of the first portion is greater than the linear density of the second portion. Also great golf shaft. The golf shaft according to claim 1, wherein the first portion exists from a center portion to a rear end. The golf shaft according to claim 1, wherein the first portion extends from a central portion to a rear end. Consists of a front end to which the head is mounted and reinforced, a rear end to which the grip is mounted, and a central portion between the front and rear ends. The outer diameter of the shaft gradually increases gradually from the front to the rear. In a fiber reinforced resin golf shaft having a tapered shape,
A golf shaft in which the linear density of the remaining portion excluding approximately 30% of the total length of the shaft from the tip of the shaft is substantially constant. It consists of a front end to which the head is mounted and reinforced, a rear end to which the grip is mounted, and a central portion between the front and rear ends. The outer diameter of the shaft extends from the front end to the rear end of the shaft. In the golf shaft made of fiber reinforced resin having a tapered shape that gradually increases gradually,
A golf shaft whose linear density is substantially constant over the entire length of the shaft. When the linear density data is approximated to the linear expression f (x) = ax + b by the least square method, the slope a of the first part is
a ≦ ± 0.000010 [(kg / m) / mm]
The golf shaft according to claim 1, wherein the deviation of the line density data with respect to the approximate straight line data is within ± 0.002 (kg / m). The golf shaft has a prepreg sheet and a braid layer arranged on the prepreg sheet, and the braid layer orientation angle of the braid layer is increased at a position where the minimum value of the linear density distribution in the prepreg sheet exists. The golf shaft according to claim 1, comprising: The golf shaft has a braided layer composed of braided yarns, and the length of the first portion that makes the linear density of the shaft substantially constant when the taper ratio of the inner diameter of the braided layer is 0.007 to 0.010. X (mm), the set angle of the first portion with respect to the distance from the shaft tip changes linearly, and the set end of the shaft from the set angle of the set yarn at the end of the first portion on the rear end side of the shaft 2. The golf shaft according to claim 1, wherein the difference Δθ (°) in the braid angle obtained by subtracting the braid angle of the braid at the end on the side is in the range of −0.03x to −0.05x. The golf shaft has a braided layer made of braided yarn, and the length of the first portion that makes the linear density of the shaft substantially constant when the taper ratio of the inner diameter of the braided layer is 0.004 to 0.006. X (mm), the set angle of the first portion with respect to the distance from the shaft tip changes linearly, and the set end of the shaft from the set angle of the set yarn at the end of the first portion on the rear end side of the shaft 2. The golf shaft according to claim 1, wherein the difference Δθ (°) in the braid angle obtained by subtracting the braid angle of the braid at the end on the side is in the range of −0.01x to −0.03x. A golf shaft made of fiber-reinforced resin and a front end portion including the rear end portion including a front end, a rear end portion including a rear end, and a central portion between the front end portion and the rear end portion, and attached to the front end portion of the shaft In a golf club having a head and a grip attached to the rear end of the shaft,
The shaft includes a first portion having an outer diameter that gradually increases from the front end to the rear end, and a linear density that is substantially constant, and a second portion other than the first portion, and the first portion is the entire length of the shaft. A golf club that is present in an amount of 30% or more and the linear density of the first part is greater than the linear density of the second part. The golf club according to claim 10, wherein the first portion exists from a center portion to a rear end of the shaft. The golf club according to claim 10, wherein the first portion extends from the central portion to the rear end of the shaft. A golf shaft made of fiber-reinforced resin and a front end portion including the rear end portion including a front end, a rear end portion including a rear end, and a central portion between the front end portion and the rear end portion, and attached to the front end portion of the shaft In a golf club having a head and a grip attached to the rear end of the shaft,
A golf club in which the linear density of the remaining portion excluding approximately 30% of the total length of the shaft from the tip of the shaft is substantially constant. A golf shaft made of fiber-reinforced resin and a front end portion including the rear end portion including a front end, a rear end portion including a rear end, and a central portion between the front end portion and the rear end portion, and attached to the front end portion of the shaft In a golf club having a head and a grip attached to the rear end of the shaft,
A golf club whose linear density is substantially constant over the entire length of the shaft.

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