JP2003102883A - Golf club shaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase a ball carry, increase the pliability and rigidity of a golf club shaft and obtain stability of the course of a struck ball and a good feeling associated with the striking of a ball. SOLUTION: On the shaft 1, the position 350 mm from the end 1a in which the shaft 1 is mounted is a point A, the position 400 mm from the end 1b in which the grip of the shaft 1 is attached is a point B, and the position 250 mm from the end 1b in which the grip of the shaft 1 is attached is a point C. The percent change of the outside diameter of the shaft between A and B is 10/1,000 or higher and 20/1,000 or lower, the flexural rigidity in the area M from the head-mounted end 1a to the point B is 3.00×10<6> kgf/mm<2> or lower, and the flexural rigidity of the area H from the point C to the grip-mounted end 1b is 5.00×10<6> kgf/mm<2> or higher.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a golf club shaft, and more specifically, it sets a rate of change in the outer diameter of the shaft and a rigidity distribution of the shaft to improve the flight distance, the directionality of a hit ball, and the feel at the time of hitting. is there.

[0002]

2. Description of the Related Art A conventional general golf club shaft is
The flexural rigidity is gradually increased from the head mounting side of the small diameter shaft to the grip mounting side of the large diameter shaft. Among these, since the shaft rigidity is proportional to the cube of the outer diameter, a shaft with a large taper change rate (outer diameter change rate) becomes a shaft with a soft tone on the head side and a hard hand side, and a shaft with a small taper change rate. Is a shaft with a hard head and a soft hand.

Since the head is easy to return and the ball is easily caught, the shaft having the above-mentioned tone is not easily sliced and has a good feeling, and the ball is easily raised, so that the flight distance is extended, and a general average golfer, especially a powerless one. Favorite by golfers.

However, when the rate of change of the outer diameter is increased to make the tone extremely extreme, the head becomes much easier to run, while the shaft is moved from the middle of the shaft to the end closer to the head side. The rigidity of the grip portion becomes too high, and it is difficult to feel the bending feeling of the entire shaft at the grip portion, and only the head mounting side portion of the shaft is largely deformed, which makes ball control difficult. Therefore, in the golf club shaft, various proposals have hitherto been made in order to achieve both the flight distance and the stability in the flight direction and to obtain a good feeling at the time of hitting.

For example, in Japanese Patent No. 2800000, a so-called Big having an outer diameter of a grip side end of 18 mm to 37 mm.
A shaft for a golf club, which is a Butt shaft, has been proposed in which a half of the entire shaft has a large-diameter portion to significantly reduce the kick point and which has an ultra-tone.

Further, in Japanese Patent Application Laid-Open No. 7-213658, the shaft length is set so that the central portion of the shaft has a flexible region having a length of 100 to 300 mm and a residual region having a bending rigidity of 50 N · m ² or more. A golf club shaft having a flexural rigidity changed accordingly has been proposed.

Further, in Japanese Unexamined Patent Publication No. 10-127838, there is a feature in that the bending-stiffness shaft has a maximum flexural rigidity set to four times or more the minimum value. And the shaft where
Two examples of shafts are disclosed in which a region where the bending rigidity increases at a rapid change rate is provided on the distal end side from the portion where the bending rigidity value is maximum.

[0008]

However, in the golf club shaft of Japanese Patent No. 2800000, although the head is easy to run, it is not possible to obtain a sufficient feeling of the shaft, so that the hitting direction is not stable, which is preferable. There is a problem that it is not possible to obtain a feeling shaft.

The golf club shaft disclosed in Japanese Unexamined Patent Publication No. 7-213658 has a low bending rigidity in a part of the shaft, which has a large manufacturing restriction and a timing change due to the abrupt change in rigidity. There is a problem that it is difficult and the feeling is bad, and that breakage due to stress concentration is likely to occur.

Further, the golf club shaft of Japanese Patent Laid-Open No. 10-127838 has a portion having the maximum bending rigidity on the tip side of the grip portion, and attention is paid to the ratio of the maximum value and the minimum value of the bending rigidity. However, the positions of the part corresponding to the minimum bending rigidity value and the part corresponding to the maximum bending rigidity value are not set by setting only the “head side” and the “grip side” of the shaft, respectively. The above problem cannot be solved only by limiting the ratio of the maximum value and the minimum value of the rigidity.

The present invention has been made in view of the above problems, and aims to increase the flight distance of a ball and to achieve both a feeling of warp and a firm feeling of the entire shaft and a high hitting direction stability and a good hit feeling. It is an object to provide the obtained golf club shaft.

[0012]

In order to solve the above-mentioned problems, according to the present invention, on the shaft axis, a position of 350 mm from the head mounting side end of the shaft is point A, and a position of 400 mm from the grip mounting side end of the shaft. B point, the point 250mm from the grip mounting side end of the shaft is C point,
Shaft outer diameter change rate between AB is 10/1000 or more 20
/ 1000 or less, and the bending rigidity of the region from the head mounting side end of the shaft to the point B is 3.00 × 1
0 ⁶ kgf · mm ² or less, and the bending rigidity of the region from the point C to the end of the shaft on which the grip is attached is 5.00
There is provided a golf club shaft having a characteristic of × 10 ⁶ kgf · mm ² or more.

That is, the bending rigidity of the golf club shaft on the proximal side is high and the bending rigidity on the head side is low, and
By setting the outer diameter change rate from near the middle of the shaft to the head direction as described above, the head is easy to run, the head speed increases, the flight distance increases and at the same time, the feeling of bending and firmness are compatible, It is possible to provide a well-balanced golf club shaft that provides stable control and further provides a good feel when hitting a ball.

The rate of change in outer diameter between AB of the above golf club shaft is set to 10/1000 or more and 20/1000 or less. When it is less than 10/1000, the head side is felt to be harder than the hand and a good tone shaft can be obtained. No, 20
If it is larger than / 1000, the shaft becomes an extreme toning shaft, so the head side is greatly deformed and the running speed becomes faster, while it is difficult to feel the bending of the entire shaft at hand, and the shot feeling and ball control deteriorate. . In addition,
The outer diameter change rate between AB is preferably 10/1000.
18/1000 or less, more preferably 10/10
00 or more and 15/1000 or less, optimal range is 11/100
The range of 0 or more and 15/1000 or less is preferable. The rate of change in outer diameter between AB is calculated by (outer diameter at point B-outer diameter at point A) / (distance between AB).

Regarding the rate of change in outer diameter other than between AB,
Outer diameter change rate from the head mounting side end to point A is 0-10 /
1000 is preferable, and the outer shape change rate from the grip attachment side end to the point B is preferably 1/1000 to 10/1000. As a result, a good feeling and shaft strength can be realized, and the grip can be easily grasped.
Further, there may be a region where the outer diameter change rate is 0, there may be an outer diameter inflection point, or the outer diameter change rate may be constant.

Further, the bending rigidity of the region from the head mounting side end of the shaft to the point B is 3.00 × 10 ⁶ kgf · mm.
By setting the number to ² or less, it is possible to sufficiently bend even the intermediate portion of the shaft and obtain a good feeling of smoothness. On the contrary, if the bending rigidity of the area is larger than 3.00 × 10 ⁶ kgf · mm ² , the shaft is not sufficiently bent and the movement of the head is difficult to transmit, making it difficult to control the ball and the ball hitting direction is not stable. . The range of the preferable bending rigidity in the region from the head mounting side end of the shaft to the point B is 0.50 × 10 ⁶ kgf · mm ² or more and 3.00 × 10 ^6.
kgf · mm ² or less, 1.00 × 10 ⁶ kgf ·
More preferably, it is not less than mm ^{2 and not} more than 3.00 × 10 ⁶ kgf · mm ² . This is 0.50 × 10 ⁶ kgf ·
This is because if it is less than mm ² , the shaft becomes too soft, the flight direction is not stable, and it is difficult to set the timing.

Further, the grip mounting of the shaft from the point C
Flexural rigidity of the area up to the side edge is 5.00 × 10⁶kgf
mm^TwoBy the above, deformation of the grip is suppressed
It is possible to obtain a firm sense of stability when hitting the ball.
It On the contrary, the bending rigidity of the area is 5.00 × 10.⁶kgf
・ Mm^TwoIf you make it smaller, you can not get a firm feeling
You can't make a bold swing because it doesn't exist. In addition,
Preferable area from point C to the end of the shaft where the grip is attached
The range of new bending rigidity is 5.00 x 10⁶kgf · mm^Two
9.00 x 10 or more⁶kgf · mm^TwoBelow, 5.
00 x 10⁶kgf · mm^Two7.00 x 10 or more⁶kg
f · mm ^TwoThe following is more preferable. This is 9.
00 x 10⁶kgf · mm^TwoEven if it is larger, the rigidity
If the effect caused by increasing it decreases,
In addition, the weight will be increased.

The reason why the point A is set at 350 mm from the end of the shaft on which the head is attached is that the beginning of the stable taper region is in this vicinity because the tip (head side) straight portion is provided. The point B is located 400 mm from the end of the shaft on which the grip is attached because the deformation of the shaft during swing is most affected by the range of 250 mm to 400 mm from the end of the shaft on which the grip is attached. C point 25 from the end of the shaft where the grip is attached
The position of 0 mm is about 25 from the grip mounting side end.
The reason is that the range up to 0 mm is in the grip, and the feeling is firmly affected.

Further, the outer diameter (diameter) of the head mounting side end of the shaft is 8.0 mm or more and 10.5 mm or less, preferably 8.5 mm or more and 9.5 mm or less, and the outer diameter of the grip mounting side end is set. It is 14.5 mm or more and 16.5 mm or less, preferably 15.0 mm or more and 16.0 mm or less. With this, the outer diameter of the grip does not become too thick while the outer diameter change rate between AB is set within the above range, so that the grip does not feel uncomfortable to grip. Specifically, the reason why the outer diameter of the head mounting side end is set in the above range is that if it is smaller than 8.0 mm, the neck is likely to be broken and the controllability is likely to be deteriorated. On the other hand, if it is larger than 10.5 mm, it is difficult to set the rate of change in the outer diameter of the shaft, and the rigidity value on the head side becomes too high, which makes the design difficult. The reason why the outer diameter of the grip mounting side end is set in the above range is that if the diameter is smaller than 14.5 mm, it is difficult to set the rate of change of the outer diameter of the shaft and it is easy to grip. On the other hand, if it is larger than 16.5 mm, the grip portion becomes too thick and it is difficult to grip.

The length of the shaft is 800 mm or more 1
200 mm or less, preferably 1000 mm or more 1170
It is good that it is less than or equal to mm. The above range is 8
This is because if it is smaller than 00 mm, the distance between AB is short and the effect of the present invention is hard to be exhibited. On the other hand, if it is larger than 1200 mm, the distance between AB is too long and the effect of the present invention is difficult to be exhibited.

The value of the forward flex, which is an index of hardness on the grip mounting side (hand side) of the shaft, is 80 mm or more and 1
It is 60 mm or less, preferably 90 mm or more and 150 mm or less. The above range is set because, if it is smaller than the above range, the shaft is too hard to form a shaft, the flight distance cannot be obtained, and the feel is bad (hard). On the other hand, if it is larger than the above range, it is too soft and the directionality is apt to deteriorate, and it becomes difficult to set timing.

The value of the reverse flex, which is an index of the hardness of the shaft on the head mounting side, is preferably 60 mm or more and 160 mm or less, and more preferably 80 mm or more and 150 mm or less for the same reason as the above-mentioned forward flex. .

It is preferable that the shaft is made of a fiber reinforced resin which is a hollow pipe-shaped laminated body in which fiber reinforced prepregs are laminated. This makes it possible to realize strength and high rigidity while being lightweight. Specifically, a straight layer in which the fiber direction of the reinforcing fiber of the fiber reinforced prepreg is parallel to the shaft axis direction, an angle layer angled with respect to the shaft axis direction, or a hoop layer perpendicular to the shaft axis direction is appropriately combined. Can be configured. Further, the bending rigidity value of the shaft can be set by appropriately adjusting the fiber direction / tensile elastic modulus of the reinforcing fibers of the fiber-reinforced prepreg, the shape / thickness / arrangement position of the fiber-reinforced prepreg, the number of layers, the number of windings, and the like. .

In the region from the position where the distance from the grip side end of the shaft is 200 mm or more and 400 mm or less to the grip side end, the tensile elastic modulus of the reinforcing fiber is 40 to.
It is preferable that one or more layers of the fiber-reinforced prepreg having nf / mm ² or more are laminated. In this way, by winding the grip side reinforcement layer to increase bending rigidity, it is possible to increase the rigidity without making the outer diameter of the grip part too thick, so that the grip feels good without causing a feeling of strangeness. In addition, the rigidity can be changed without increasing the weight of the shaft. The fiber reinforced prepreg has one or more layers, preferably two or more layers. The region around which the reinforcing layer is wound is preferably at least 200 mm or more and at most 400 mm or less from the grip side end of the shaft so as not to impair the rigidity distribution of the present invention. The thickness of the prepreg
Similar effects can be obtained by appropriately changing the tensile modulus and the number of windings.

As the resin used for the fiber reinforced resin,
Thermosetting resins and thermoplastic resins are mentioned, and these can be used alone or in combination. A thermosetting resin is preferable from the viewpoint of strength and rigidity, and an epoxy resin is particularly preferable. In addition to epoxy resins, examples of thermosetting resins include unsaturated polyester resins (vinyl ester resins). Further, examples of the thermoplastic resin include polyamide resin and saturated polyester resin.

As the reinforcing fibers used in the fiber-reinforced resin, fibers generally used as high-performance reinforcing fibers can be used. In addition to carbon fibers, for example, glass fibers, graphite fibers, aramid fibers, silicon carbide fibers, alumina fibers, boron fibers, aromatic polyamide fibers, aromatic polyester fibers, ultra-high molecular weight polyethylene fibers, etc. may be mentioned. Moreover, you may use a metal fiber. Carbon fiber is preferable because it is lightweight and has high strength. These reinforcing fibers may be long fibers or short fibers, and two or more kinds of these fibers may be mixed and used. The shape and arrangement of the reinforcing fibers are not limited, and for example, any shape and arrangement such as a single direction, a random direction, a sheet shape, a mat shape, a woven (cloth) shape, and a braided shape can be used.

The shaft may be made of a metal shaft (steel shaft) instead of the fiber reinforced resin. When the shaft is made of metal, the rigidity distribution and the like can be appropriately changed by adjusting the outer diameter distribution and the wall thickness distribution of the shaft.

Further, the golf club shaft of the present invention is
It can be applied to all kinds of golf clubs such as wood type clubs, iron type clubs and putters.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIGS. 1 to 4 show a golf club shaft according to a first embodiment of the present invention.
It is made of a laminated body of fiber reinforced prepregs, has a hollow pipe shape having a hollow portion, and has a head 2 on the small diameter end side of the shaft 1.
Is attached, and the grip 3 is attached to the large diameter end side. The shaft 1 has a tapered shape in which the diameter is linearly expanded from the head mounting side to the grip mounting side.

Outer diameter D of the head mounting side end 1a of the shaft 1
1 is 9.0 mm, and the outer diameter D2 of the grip mounting side end 1b
Is 16.1 mm. Further, on the shaft axis i, 350 m from the head mounting side end 1a of the shaft 1
A position separated by m, point 1 on the grip mounting side of shaft 1
Position B 400 mm away from point b, also shaft 1
At a position 250 mm away from the grip mounting side end 1b of C
And the rate of change in outer diameter between AB is 11/1000. The total length of the shaft is 1150 mm and the weight of the shaft is 54 grams.

The shaft 1 is manufactured by a sheet winding method in which the prepregs 11 to 18 shown in FIG. 3 are sequentially wound around a mandrel (not shown) from the inside.
The prepregs 11 to 18 are fiber reinforced prepregs in which carbon fibers are reinforced fibers and matrix resin is epoxy resin.

The prepregs 11 and 12 are made of the reinforcing fiber F.
11, F12 is inclined 45 degrees to the shaft axis,
The tensile elastic modulus of the reinforcing fiber is 30 tonf / mm ² , a bias layer for increasing the torsional rigidity is formed, the prepreg length is 1170 mm, and the mandrel is on the head side 4.
It is designed to be wound twice and twice on the grip side. The prepreg 13 is a rear end reinforcing layer that is wound around the portion where the grip is attached, and has a tensile elastic modulus of 40 tons.
It is set to nf / mm ² and is wound twice. The prepreg 13 is 350 m from the grip side end 1b so that the reinforcing fiber F13 is parallel to the shaft axis.
The straight layer is wound in the range of m to enhance the bending rigidity in the vicinity of the grip mounting portion. The length of the long side is 350 mm and the length of the short side is 200 in the shaft axis direction.
mm. Each of the prepregs 14 to 16 is wound once, the reinforcing fibers F14 to F16 are parallel to the shaft axis, and the tensile elastic modulus of the reinforcing fibers is 30 tonf /
mm ² , the prepreg length is 1170 mm, and a straight layer that enhances bending rigidity is configured. The prepregs 17 and 18 are short lengths that reinforce the head mounting portion and increase rigidity. The major side is wound 4 times, the tensile elastic modulus of the reinforcing fiber is 24 tonf / mm ² , and the prepreg length is 25.
It is set to 0 mm, and the reinforcing fibers F17 and F18 form a straight layer that is parallel to the shaft axis.

By configuring the shaft 1 as described above,
As shown in the flexural rigidity value distribution (EI distribution) of FIG. 4, the flexural rigidity of the region M from the head mounting side end 1a of the shaft 1 to the point B is 3.00 × 10 ⁶ kgf · mm ² (3.00 k
gf · m ² ) or less, and the bending rigidity of the region H from the point C to the grip mounting side end 1b of the shaft 1 is 5.0.
It becomes 0 × 10 ⁶ kgf · mm ² (5.00 kgf · m ² ) or more, and the shaft 1 becomes an appropriate tone shaft.

Therefore, the ball is easy to go up without slicing, the flight distance is extended, and the stability in the flight direction is good. Further, since the bending rigidity of the head mounting side end 1a is low from the point B, the shaft 1 becomes sufficient from the middle portion, and a soft feel at impact can be obtained. Further, since the bending rigidity is increased from the point C to the grip mounting side end 1b, the deformation of the grip 3 is suppressed, the stability at the time of hitting the ball is good, a bold swing is possible, and the reinforcing layer is wound. By increasing the rigidity, it is possible to suppress an increase in weight and the grip 3 from becoming too thick. In addition, since a sufficient dimension is secured for the outer diameter D1 of the head mounting side end 1a, sufficient strength can be obtained, shaft breakage can be prevented, and the outer diameter D of one grip mounting side end 1b can be prevented.
Since the size of 2 is suppressed, it can be gripped without any discomfort.

Hereinafter, examples and comparative examples of the present invention will be described in detail. In order to confirm the above, first, each item value is set as shown in Table 1 below, and Example 1 of the present invention is set.
.About.4 and Comparative Examples 1 to 4 were produced.

[0036]

[Table 1]

(Example 1) A shaft having the same structure as that of the first embodiment was used. Toray M30S is used for prepregs 11 and 12, and Toray M40 is used for prepreg 13.
J was used, M30S manufactured by Toray was used for the prepregs 14 to 16, and T700S manufactured by Toray was used for the prepregs 17 and 18.

(Examples 2 to 4) The basic structure of the prepreg is the same as that of the first embodiment, but the mandrel, prepreg material, etc. are appropriately selected so that the set values shown in Table 1 are obtained.
Each golf club shaft was obtained by designing. In Example 2, the rear end reinforcing layer is YS manufactured by Nippon Graphite Fiber Co., Ltd.
-80 In Example 3, YS manufactured by Nippon Graphite Fiber Co., Ltd.
-60 In Example 4, M50J manufactured by Toray Industries, Inc. was used. The flexural rigidity (EI) distribution was set by the mandrel taper and the rear end reinforcing layer.

(Comparative Examples 1 to 4) The basic structure of the prepreg is the same as that of the first embodiment, but the mandrel, the material of the prepreg, etc. are appropriately selected so that the set values shown in Table 1 are obtained.
Each golf club shaft was obtained by designing. The rear end reinforcing layer was M30J manufactured by Toray in Comparative Example 1, M46J manufactured by Toray in Comparative Example 2, T40S manufactured by Toray in Comparative Example 3, and M40J manufactured by Toray in Comparative Example 4. The flexural rigidity (EI) distribution was set by the mandrel taper and the rear end reinforcing layer.

For each of the above Examples and Comparative Examples, the bending stiffness values at the points A, B, C and the grip side (BUTT) end, and the bending stiffness values from the head side end to the point B (hereinafter referred to as "head"). Abbreviated as "side rigidity value") is 3.00 x 1
0 ⁶ kgf · mm ² (3.00 kgf · m ² ) or less (hereinafter abbreviated as “reference range”), “O” or “X”, C
The bending rigidity value from the point to the end on the grip side (hereinafter abbreviated as “grip side rigidity value”) is 5.00 × 10 ⁶ kgf · mm ²
It was determined by measuring whether or not “◯”, which is (5.00 kgf · m ² ) or more (hereinafter abbreviated as “reference range”), and “x”. Further, flex and tone ratio were determined by the methods described below.

(Measurement of EI (Flexural Rigidity) Value) As shown in FIG.
The measurement was performed with the shaft 1 as a boundary. The EI value was calculated by the following formula. Determine the measurement point and perform TIP from the measurement point
Side and the BUTT side respectively support points separated from each other by (L (distance between fulcrums) / 2) from below, and set the shaft 1 to the jig 62A so that the measurement point is below the indenter 61 of the universal testing machine 60. 6
Placed on top of 2B. The distance between the jigs 62A and 62B (distance between fulcrums) was 200 mm. The curvature of the tip of the indenter 61 is R10 mm, and the curvature of the tip of the jigs 62A and 62B is R2 m.
m. The indenter 61 was lowered at a test speed of 5 mm / min so that the shaft 1 was bounded. Load load is 20 kg
The movement of the indenter 61 was completed at the time point when f was reached, and the boundary amount of the shaft 1 at that time was measured. EI (kg · mm ² ) = (load load × (distance between fulcrums) ³ ) / (48 × border amount) The measured value was converted to kg · m ² .

Further, FIG. 6 shows Examples 1 to 4 and Comparative Example 1
Bending rigidity value distributions (EI distributions) of 4 to 4 are shown in the graph together with the distance from the end on the head mounting side.

(Measurement Method of Flex) The above-mentioned forward flex is an index of hardness on the grip side (hand side) of the shaft, and was measured at a position of W45 inches. Figure 7
As shown in (A), a position 799 mm from the tip is set as a fulcrum P1, and from this fulcrum P1 to a point 140 from the grip end A.
The position of mm is the fixed point P2, and 64 from the head mounting end D
It is obtained by suspending a 2.7 kg weight W1 at a position of mm and measuring the amount of deflection of the head attachment end D. The reverse flex is an index of the hardness of the shaft on which the head is mounted, and as shown in FIG.
Is set as a fulcrum P1 ', and a position 140 mm from the fulcrum P1' to the head mounting side is a fixed point P2 ', and a 1.3 kg weight W2 is hung at a position 798 mm from the head mounting end D, and a grip mounting end is formed. It is obtained by measuring the amount of deflection of A.

(Calculation method of tone rate) The tone (%) is
Reverse flex / (Forward flex + Reverse flex)
It is calculated by × 100 and represents the tone ratio. The higher the tone rate, the better the tone.

(Feeling Test) Next, a 46-inch driver club was assembled using the golf club shafts of Examples 1 to 4 and Comparative Examples 1 to 4, and a "flexibility" was obtained.
An evaluation of "firm feeling" and "overall preference" and an actual hit test regarding flight distance were conducted. The results are shown in Table 2 below. In this actual hitting test, eight golfers scored each item with the following 5-point perfect score, and Table 2 shows the average of the scored results of all the golfers. Flexibility: Large 5 → 1 Small Firm feeling: Large 5 → 1 Small Overall preference: Like 5 → 1 Dislike 8 golfers hit 5 balls each
The average value of all flight distances is shown.

[0046]

[Table 2]

As can be seen from the EI value distribution graph shown in Table 1 and FIG. 6, in each of Examples 1 to 4, both the head-side rigidity value and the grip-side rigidity value are within the reference range, and the outside of the shaft is used. Diameter change rate is also 11/1000 (1.1E-
02) was within the specified range. On the other hand, in Comparative Examples 1 to 4, except for Comparative Example 4, at least one of the head-side rigidity value and the grip-side rigidity value is outside the reference range. For Comparative Example 4, the outer diameter change rate between AB was 7.
It is as small as 8/1000 (7.8E-03) and has the lowest tone rate. In particular, the outer diameter change rate is 8.3 / 1000 of Comparative Example 1.
Along with (8.3E-03), the shaft had a hand condition of less than 10/1000.

Therefore, as can be seen from the results of the actual hit test in Table 2, in Examples 1 to 4, the evaluations of "flexibility" and "firmness" are high, the flight distance is large, and "comprehensive preference" is given. Was also high.

On the other hand, Comparative Example 1 in which both the head-side rigidity value and the grip-side rigidity value are outside the reference range and the rate of change in outer diameter between AB is also the lowest evaluation, and the flight distance was not extended. In addition, Comparative Example 2 in which only the stiffness value on the head side is outside the reference range has a particularly low “flexing feeling”, and Comparative Example 3 in which only the rigidity value on the grip side is outside the reference range has a particularly “firm feeling”. In the example, the flight distance did not increase. From this result,
If both the stiffness value on the head side and the stiffness value on the grip side are not within the standard range, both "flexibility" and "firmness" are achieved,
Moreover, it was confirmed that it is difficult to extend the flight distance. Further, in Comparative Example 4 in which both the head-side rigidity value and the grip-side rigidity value are within the reference range, but the outer diameter change rate between AB is less than 10/1000, both "flexibility" and "firm feeling" are obtained. It was low, and the flight distance was the shortest.

From these results, in addition to the fact that both the head-side rigidity value and the grip-side rigidity value are within the reference range, if the outside diameter change rate between AB is not within the specified range, "flexibility" and " I was able to confirm that it had a solid effect "and that it had a bad effect on flight distance.

[0051]

As is apparent from the above description, in the golf club shaft of the present invention, between the points A separated by 350 mm from the head mounting side end and the point B separated by 400 mm from the grip mounting side, among the shafts. Focusing on the outside diameter change rate of the area,
Since it is set within the range of 0 or less, it is possible to obtain an appropriate tone and secure a flight distance. Further, the bending rigidity value from the point B to the head mounting side end is 3.00 × 10 ⁶ kgf
· Mm ² or less, by the flexural rigidity of 250mm regions from the grip mounting side end to distribute the stiffness value bent such that 5.00 × ¹⁰ 6 kgf · mm ² or more, without enough from the shaft intermediate portion In addition to providing a good feel, a firm and stable feeling is obtained at the grip portion, and a well-balanced and good shot feeling can be obtained as a whole.

Further, the outer diameter of the head mounting side end is 8.0 m.
By setting the outer diameter of the grip mounting side end to 14.5 mm or more and 16.5 mm or less, the outer diameter change rate is set in the above range, but the head side of the shaft becomes too thin. Therefore, it is possible to prevent the shaft from easily breaking, and to prevent the grip side of the shaft from becoming too thick, which makes the golf club shaft uncomfortable to grip, so that a golf club shaft having a good feeling can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic view of a golf club using a golf club shaft according to a first embodiment of the present invention.

FIG. 2 is an external view of the golf club shaft of the first embodiment.

FIG. 3 is a diagram showing a prepreg that constitutes the golf club shaft of the first embodiment.

FIG. 4 is a diagram showing a flexural rigidity value distribution of the golf club shaft of the first embodiment.

FIG. 5 is a diagram showing a method of measuring a bending rigidity value of a shaft.

FIG. 6 is a diagram showing distributions of flexural rigidity values of shafts of Examples and Comparative Examples.

FIG. 7A is a diagram showing a forward flex measurement method, and FIG. 7B is a diagram showing a reverse flex measurement method.

[Explanation of symbols] 1 shaft 1a Head mounting side end 1b Grip mounting side end 2 heads 3 grip

Claims (3)

[Claims] 1. On the shaft axis, a position 350 mm from the head mounting side end of the shaft is point A, a position 400 mm from the grip mounting side end of the shaft is point B, and a position 250 mm from the grip mounting side end of the shaft is C. The shaft outer diameter change rate between AB is 10/1000 or more 20
/ 1000 or less, and the bending rigidity of the region from the head mounting side end of the shaft to the point B is 3.00 × 1
0 ⁶ kgf · mm ² or less, and the bending rigidity of the region from the point C to the end of the shaft on which the grip is attached is 5.00
A golf club shaft having a density of × 10 ⁶ kgf · mm ² or more. 2. The outer diameter of the head mounting side end of the shaft is 8.0 mm or more and 10.5 mm or less, and the grip mounting side end of the shaft is 14.5 mm or more and 16.5 mm or less. Golf club shaft. 3. The shaft is made of a fiber reinforced resin consisting of a laminate of fiber reinforced prepregs, and the reinforcing fiber is provided in a region from a position where the distance from the grip side of the shaft is 200 mm or more and 400 mm or less to the grip side end. Has a tensile elastic modulus of 40 tonf / mm ²
The golf club shaft according to claim 1 or 2, wherein one or more layers of the fiber-reinforced prepreg as described above are laminated.