JP2000325511A - Shaft for golf club and golf club using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shaft for golf clubs which can increase the degree of freedom in the design of a head weight. SOLUTION: This shaft 1 for golf clubs of an inner hosel type is constituted by inserting its front end T into a shaft mounting hole formed at the hosel of the club head and mounting a grip at its rear end B. The shaft 1 includes an equal diameter part 2 which has a substantially constant outside diameter Da and extends from the front end T to the rear end B side, a first tapered part 3 which is continuous with the equal diameter part 2 and is gradually decreased in the outside diameter toward the rear end side and a second tapered part 3 which is continuous with the first equal diameter part 2 and is gradually increased in the outside diameter toward the rear end side. The outside diameter Da of the equal diameter part 2 is set at 9.0 to 15.0 mm.

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 capable of increasing the degree of freedom in designing the weight of a head and a golf club using the shaft.

[0002]

2. Description of the Related Art In recent years, golf clubs have been developed to improve ease of hitting. For example, the shaft has been made longer, the head has been made larger and lighter, and the center of gravity has been lowered to make it easier to raise the ball. And so on. In order to lower the center of gravity of the head, weight distribution design such as distributing the weight of the head to the sole becomes important. As shown in FIG. 10A, a hosel d having a mounting hole e for mounting a shaft c is usually formed on the head b so as to protrude upward (inner hosel type). Reducing the weight of the hosel d is useful for lowering the center of gravity of the head b.

To reduce the weight of the hosel of the head, a so-called over hosel type golf club has been proposed. In this golf club, as shown in FIG. 10B, a hosel d of a head b is connected to a stepped pin f.
This is inserted into the hollow portion of the shaft c and bonded and integrated. For this reason, it is possible to reduce the size of the hosel d.

[0004]

However, even in the above-mentioned over hosel type golf club, in order to increase the adhesive strength between the hosel and the shaft and to prevent the head from coming off, the length of the pin f must be reduced. Since it needs to be large, a sufficiently low center of gravity cannot be expected. Japanese Patent Laid-Open No. Hei 9-173516 has proposed a shaft for a golf club of such an over hosel type.
However, such a shaft is required to have sufficient strength to prevent breakage of the pin f or the like having a reduced diameter, and in particular, the bending rigidity and the torsional rigidity of the shaft tip attached to the hosel become excessive. Average golfers tend to lose flight distance.

The present invention has been devised in view of such a situation, and is based on an inner hosel type golf club shaft having a tip inserted into a shaft mounting hole formed in a hosel of a club head. Based on the provision of an equi-diameter portion that extends from the rear end side to a substantially constant and large outer diameter, even if the hosel is shortened, the mounting hole and a sufficient bonding area can be secured and the bonding strength can be maintained, In addition, it is an object of the present invention to provide a golf club shaft and a golf club using the same, which can increase the degree of freedom in the head weight distribution design using the reduced hosel weight.

[0006]

According to a first aspect of the present invention, there is provided an inner hosel type golf having a tip inserted into a shaft mounting hole formed in a hosel of a club head and a grip attached to a rear end. A club shaft, having a substantially constant outer diameter extending from the front end to the rear end side and an equal diameter section connected to the equal diameter section and having an outer diameter gradually decreasing toward the rear end side. 1 and a second tapered portion connected to the first tapered portion and having an outer diameter gradually increasing toward the rear end side, and the outer diameter of the equal diameter portion is 9.0. -15.0 mm.

The equal-diameter portion has an axial length of 50.0 mm.
It is preferable that the diameter is equal to or less than 100.0 mm.
It is desirable to be reinforced with a fiber-reinforced resin containing a reinforcing fiber having a tensile modulus of 15000 kgf / mm ² or less.

Further, the golf club shaft is formed by inserting the equal diameter portion of the golf club shaft into a shaft mounting hole of the hosel, and attaching a grip to the rear end of the golf club shaft to form a golf club. Can. At this time, the equal-diameter portion includes an adhesive portion bonded to the shaft mounting hole via an adhesive, and a protruding portion protruding from the shaft mounting hole, and has an axial length of 21. It is preferable that the length is in the range of 5 to 36.0 mm, and the length of the protruding portion in the axial direction is in the range of 20 to 50 mm.

In the case of a wood type golf club,
The constant diameter portion has an outer diameter of 9.0 to 13.0 mm, and an axial length of the bonding portion is 25.0 to 36.0 mm,
Moreover, it is desirable that the length of the protruding portion in the axial direction is 20 to 50 mm. On the other hand, when the iron-type golf club is used, the outer diameter of the equal diameter portion is 10.0 to 15.0 mm.
And the length of the bonding portion in the axial direction is 21.5 to 3
2.0 mm, and the axial length of the protruding portion is 2 mm.
It is desirable to set it to 0 to 50 mm.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an overall plan view of a golf club shaft (hereinafter, may be simply referred to as a “shaft”) 1 of the present embodiment, and FIG. 2 (b) is an XX end view of FIG. 2 (a), and FIG. 2 (c) is a YY, ZZ end view of FIG. 2 (a).

The shaft 1 of this embodiment has a tip T shown in FIG.
As shown in FIG. 1, an inner hosel type golf club shaft to be inserted into a shaft mounting hole 10 formed in a hosel 9 of a club head H.
It is set to about 38 to 1270 mm. Also shaft 1
As shown in FIGS. 1 and 2, includes an equal diameter portion 2, a first taper portion 3, and a second taper portion 4. In the present embodiment, the equal diameter portion 2, the first taper portion 3, An example in which the hollow shaft 1 is constituted by the second tapered portion 4 is illustrated.

The constant diameter portion 2 has a substantially constant outer diameter Da.
To extend from the front end T to the rear end B side. In addition, a large outer diameter Da of 9.0 to 15.0 mm is employed for the equal diameter portion 2.
The equal diameter portion 2 having such a large outer diameter can secure a sufficient bonding area even if the hosel 9 of the club head H is shortened, for example. Therefore, such a shaft 1 can make it possible to shorten the hosel 9 of the club head H while preventing the head from coming off. Note that the reduced weight of the hosel 9 can be further distributed to other portions of the club head H, for example, a sole portion to reduce the center of gravity, so that the degree of freedom in head weight distribution design can be further increased.

Here, the outer diameter Da of the constant diameter portion 2 is 9.0 mm.
If it is less than this, it will be difficult to secure the same bonding area as before while shortening the hosel 9, and conversely, if the outer diameter Da of the equal diameter portion 2 exceeds 15.0 mm, The weight tends to be excessively increased, so that the club balance becomes large and it becomes difficult to swing, and in addition, uncomfortable feeling at the time of holding and breakage of the shaft are likely to occur. From such a viewpoint, it is desirable that the outer diameter Da of the equal diameter portion 2 be 10.0 to 12.5 mm. It is sufficient that the constant diameter portion 2 has an outer diameter that is “substantially” constant. For example, a manufacturing error or the like can be allowed.

If the axial length La of the equal diameter portion 2 is too short, the shaft may be broken. On the other hand, if the length La is too long, the weight at the tip of the shaft increases, and the balance is deteriorated. Is more likely to occur. From such a viewpoint, for example, the axial length La of the equal-diameter portion 2 is preferably 50 to 100 mm, and more preferably 65 to 85 mm.

The first tapered portion 3 is continuous with the constant diameter portion 2 and has an outer diameter gradually reduced toward the rear end B, and the second tapered portion 4 is formed of the first tapered portion 4. And the outer diameter gradually increases toward the rear end B side. Since the first tapered portion 3 and the second tapered portion 4 are provided on the rear end B side of the equal diameter portion 2 as described above, a constricted portion is formed.
It is possible to effectively reduce an increase in rigidity of the distal end portion of the shaft due to the large outer diameter equal diameter portion 2. Accordingly, it is possible to prevent the rigidity of the distal end portion of the shaft 1 from becoming excessively large, and to suppress, for example, loss of a flight distance and difficulty in raising a ball.

Here, the axial length Lb of the first tapered portion 3
Is too small, the outer diameter of the tapered portion changes sharply in order to moderately reduce the bending stiffness at the tip of the shaft 1, or breakage due to the concentration of impact stress at the time of hitting the ball occurs, and further, surface polishing There are problems such as impairing workability of processing. Conversely, if the length Lb in the axial direction of the first tapered portion 3 is too large, the bending rigidity of the shaft may be increased, and there is a problem that a sense of incongruity occurs when holding the shaft. From such a viewpoint, for example, the axial length Lb of the first tapered portion 3 is preferably 20 to 150 mm, more preferably 30 to 100 mm, and still more preferably 40 to 100 mm.
mm is desirable.

In the present embodiment, an example is shown in which the axial length Lb of the first tapered portion 3 is smaller than the axial length La of the constant diameter portion 2. Further, the first taper portion 3 is illustrated as an example in which the outer diameter changes small at a constant rate in the axial direction. However, examples of the “outer diameter gradually decreasing toward the rear end side” include those in which the rate of change in the outer diameter is non-constant, in addition to those in which the outer diameter changes at a constant rate.

As shown in FIG. 3, the first tapered portion 3
Of the first taper portion 3 with the axial length Lb,
Of the maximum radius Rm and the minimum radius Rs of the tapered portion 3 (R
m−Rs) and {(Rm−Rs) / Lb}. If the gradient of the first tapered portion 3 is too small, the weight of the distal end side of the shaft 1 tends to be too large, making it difficult to swing, and the above-mentioned rigidity relaxing effect of the distal end portion of the shaft 1 is insufficient. Becomes Conversely, if the gradient is too large, the change in the outer diameter tends to be sharp, which may lead to stress concentration and breakage. From such a viewpoint, the gradient of the first tapered portion 3 is preferably 1/1.
000 to 1/10, more preferably 5/100
It is desirable to set in the range of 0 to 5/100.

In this embodiment, the second tapered portion 4 is connected to the first tapered portion 3 and extends to the rear end B of the shaft 1. However, the present invention is not limited to this, and another constant diameter portion or a tapered portion having another gradient may be provided on the rear end side of the second tapered portion 4.

Such a second tapered portion 4 has, for example, a gradient of 1 (specified similarly to the first tapered portion 3).
It is preferably set to about / 1000 to 15/1000. In the present example, the second tapered portion 4 has an outer diameter that changes greatly at a constant rate in the axial direction. However, similarly to the first tapered portion 3, the present invention also includes those having a variation rate of the outer diameter that is not constant. Also, the rear end B of the shaft 1
Is formed to be larger than the outer diameter Da of the equal diameter portion 2, but this value can be determined as appropriate. Preferably, the outer diameter of the rear end B of the shaft is 10 to
It is desirable to set it to 30 mm.

Such a golf club shaft 1 comprises:
For example, it can be manufactured by laminating sheet-shaped prepregs obtained by impregnating a thermosetting resin into reinforcing fibers aligned in parallel. For example, after winding such a prepreg around a mandrel to obtain a cylindrical laminate, the laminate is once de-centered from the mandrel, and an inflatable bladder or the like is inserted into the hollow portion of the laminate, and the pressure is reduced. By pressing the laminate against the inner surface of the mold while applying heat, the shaft 1 having the above-described shape can be formed.

A so-called tape wrapping method in which a prepreg is wound around a mandrel to obtain a laminate, a tape is wound and cured, and then the mandrel is pulled out and molded. The bundle may be formed by directly winding the bundle around a mandrel to obtain a laminate, a so-called “filament winding method” or the like. After molding, the surface of the shaft may be polished, painted, or the like as appropriate.

As the reinforcing fiber of the prepreg, various ones can be adopted. For example, in addition to carbon fiber and glass fiber, boron, titanium, tungsten, stainless steel,
Examples thereof include metal fibers made of copper, alumina, and the like, and aramid fibers, and one or more of these can be used. Examples of the thermosetting resin constituting the prepreg include an epoxy resin, an unsaturated polyester resin, a phenol resin, and a vinyl ester resin, and one or more of these resins can be used.

The shaft 1 of the present embodiment is, for example, manufactured by using prepregs S1 to S11 as shown in FIG. The prepreg of the present example is an elongated main prepreg Sa substantially constituting the entire length of the shaft,
And a small-piece-shaped auxiliary prepreg Sb laminated on the tip portion of the shaft.

A plurality of main prepregs Sa, in this example, S
1 to S6, which are cut in a rectangular or trapezoidal shape in advance. These are sequentially wound around the mandrel from the upper side in the figure. Such a main prepreg Sa has, for example, a tensile modulus of elasticity of 24000.
Those containing reinforcing fibers made of PAN-based carbon fibers of kgf / mm ² or more are preferable. Thereby, the shaft 1
The basic bending stiffness and the like can be obtained.

FIG. 4 shows the directions of the reinforcing fibers F of the prepregs Sa and Sb by chain lines. The main prepreg Sa of the present example has reinforcing fibers F arranged at an angle of 30 to 60 ° with respect to the axial direction of the shaft (S1, S1).
2) Includes those in which the reinforcing fibers F are arranged along the axial direction of the shaft (S3, S5, S6) and those in which the reinforcing fibers F are arranged along the circumferential direction of the shaft (S4). By including a variety of reinforcing fibers having different orientations, the bending rigidity, durability, and tear resistance of the shaft can be improved.

The auxiliary prepreg Sb includes a plurality of sheets, in this example, five sheets S7 to S11. In this example, the auxiliary prepreg Sb is cut in a triangular or trapezoidal shape in advance. Such an auxiliary prepreg Sb has, for example, a tensile modulus of 15000 kgf / mm ² or less, preferably 5000 to 5000 kgf / mm ^2.
It is desirable to include 10,000 kgf / mm ² of reinforcing fibers. As such reinforcing fibers, pitch-based carbon fibers or glass fibers are preferable.

By using such a main prepreg Sa and an auxiliary prepreg Sb, at least the equal-diameter portion 2 of the shaft 1 is reinforced by a fiber-reinforced resin containing a reinforcing fiber having a tensile modulus of 15000 kgf / mm ² or less. . FIG.
(B) illustrates a cut end face of XX of the equal diameter portion 2. The equal-diameter portion 2 includes a main portion P1 formed of a main prepreg Sa, and an auxiliary portion P2 disposed outside the main portion P1 and formed of an auxiliary prepreg Sb including the reinforcing fiber having a low elastic modulus. On the other hand, in this example, the first,
The second taper portions 3 and 4 are formed by the main portion P1 substantially formed of the main prepreg Sa, and have a smaller thickness than the equal diameter portion 2 as an example. .
In this example, the reinforcing fibers F of the auxiliary prepreg Sb are all oriented in the axial direction of the shaft 1.

The relatively low-elasticity reinforcing fibers disposed in the equal-diameter portion 2 prevent the tip portion of the shaft 1 from excessively increasing the rigidity, and reduce the thickness of the equal-diameter portion 2 to other portions. (First
The taper portion 3 and the second taper portion 4) can also be increased, and the durability and tear characteristics of the shaft can be suitably improved. The thickness of each part such as the equal diameter part 2, the first taper part 3, and the second taper part 4 may be substantially uniform as shown in an exaggerated manner in FIG. In order to facilitate the pulling out of the mandrel, for example, as shown in an exaggerated manner in FIG. 2B, the equal diameter portion 2 and the first tapered portion 3 have substantially the same inner diameter, or FIG. As shown in an exaggerated manner, the inner diameter can be gradually increased toward the rear end side.

FIG. 6 illustrates a golf club G using the shaft 1 described above. The golf club G includes the shaft 1, the club head H, and a grip (not shown).
And In the present embodiment, the golf club G is, for example, a wood-type golf club WG, and includes a crown part 5, a side part 6, a sole part 7, and a hosel 9 protruding from the crown part 5 on the heel side of the crown part 5. Having.

The hosel 9 has a shaft mounting hole 10.
Are formed. The shaft mounting hole 10 extends from the outer end 9a of the hosel 9 to the inside of the head H by penetrating through the hosel 9 and the support portion 11 connected to the hosel and extending to the inside of the head. .
Further, the inner diameter of the shaft mounting hole 10 is formed, for example, slightly larger than the outer diameter Da of the equal diameter portion 2 of the shaft 1. The equal-diameter portion 2 of the shaft 1 is inserted into the shaft mounting hole 10 and integrated with an adhesive.

In the golf club G of the present embodiment, an equal diameter portion 2 of the shaft 1 is bonded to the shaft mounting hole 10 via an adhesive, and an outer portion of the head H from the shaft mounting hole 10. A preferred embodiment including the protruding portion 2b that protrudes is illustrated.

Since the shaft 1 is provided with the large-diameter portion 2 having a large outer diameter at the tip end T as described above, the axial length La1 of the bonding portion 2a can be reduced while maintaining the bonding area at the same level as the conventional one. In other words, it is possible to reduce the length of the hosel 9,
The weight of the club head H can be reduced. Also hosel 9
Can be distributed to the sole portion 7 and the like, and the center of gravity of the club head H can be further reduced. In this example, even when the head volume of the wood-type club head H is 300 cc or more, as shown in FIG. 9, a leg perpendicular to the face from the center of gravity GP of the head is used as a sweet spot SS, and this sweet spotpot is used. The height h can be designed to be smaller than 32 mm.

In the case of a wood type golf club WG,
Generally, the flight distance performance tends to be regarded as important, so that the distal end portion of the shaft 1 needs to have an appropriate softness (bending feeling). In addition, since there are many opportunities to hit the ball by teeing up and the swing tends to be blown out, it acts on the bonding portion between the shaft 1 and the head H as compared with an iron type golf club which hits the grass surface by so-called down blow. The impact is small. From such a viewpoint, in the case of the wood type golf club WG, the outer diameter Da of the equal diameter portion 2 is, for example, 9.0 to 13.0 mm, more preferably 9.5 to 12.0 mm, and the above range. It is particularly preferable to set the diameter to the smaller diameter side.

If the length La1 of the bonding portion 2a in the axial direction is too small, an unbalanced load or the like acts on the tip T of the shaft 1, which may cause not only breakage of the tip but also dropout of the head. If the axial length La1 of the bonding portion 2a is too large, the hosel 9 of the club head H is inevitably long, which tends to hinder the design flexibility of the head. From such a viewpoint, for example, the axial length La1 of the bonding portion 2a is preferably 21.5 to 36.0 mm, more preferably 25.0 to 36.0 mm, and still more preferably 25.0 to 36.0 mm.
It is desirable to be 7.0 to 34.0 mm.

The axial length L of the protruding portion 2b
If a2 is too small, the rigidity of the distal end of the shaft 1 may be reduced and breakage may occur.
If the axial length Lb2 is too large, the player tends to feel uncomfortable when the club G is held. From such a viewpoint, the axial length La2 of the protruding portion 2b is, for example, 20 to 50 mm,
More preferably, it is desirable to set it to 20 to 30 mm.
The total length L of the shaft is preferably 1016 to 1270 mm.

FIG. 7 illustrates an iron type golf club IG using the shaft 1 of the present embodiment. The iron type golf club IG also includes the hosel 9 including the shaft 1, the club head H, and a grip (not shown), and protruding from the heel side of the head H. In the case of the iron-type golf club IG, the directionality and the stability of the flight distance tend to be more important than the flight distance performance as compared with the wood-type golf club. Moderate hardness (firm feeling) is required. From such a viewpoint, in the case of the iron type golf club IG, the outer diameter Da of the equal diameter portion 2 is, for example, 1
0.0-15.0 mm, more preferably 11.0-13.
It is particularly preferable to set 5 mm to the larger diameter side within the above range.

The axial length La1 of the bonding portion 2a is preferably 21.5 to 36.0 mm, more preferably 21.5 to 32.0 mm, and further preferably 23.
It is desirable to set it to 5 to 29.5 mm, and the axial length La2 of the protruding portion 2b is, for example, 20 to 50 mm, more preferably 20 to 30 like a wood type golf club.
mm is desirable. In this case, the total length L of the shaft is preferably 838 to 1016 mm.

[0039]

EXAMPLES In order to confirm the effects of the present invention, a plurality of shafts were prototyped according to the specifications shown in Table 1, and a wood-type club head was fixed to the shafts with an adhesive, and the torque of the bonded portion was adjusted. Tests were conducted on breaking strength, durability, ease of holding, ease of swing, and the like. The prepreg used for the shaft is generally based on the one shown in FIG. 4 (the numerical values are in mm and the auxiliary prepregs S8 to S11 have the same shape). The main prepreg is composed of PAN-based carbon fiber as a reinforcing fiber, The prepreg used was a pitch-based carbon fiber. In addition, the thickness of the equal diameter portion of each shaft is 1.
5 to 5.0 mm, thickness of the first tapered portion is 0.7 to 5.0
mm, and the thickness of the second tapered portion was 0.7 to 1.0 mm.

The club head has a different sweet spot height due to a difference in the length of the shaft mounting hole (length of the hosel) of the head, and the specifications are shown in Table 2. Further, by changing the shape and thickness of the head, changes in head weight and head volume due to the difference in the length of the shaft mounting hole of each club head are eliminated. As shown in FIG. 9, the sweet spot height was measured as the vertical height h of the sweet spot SS, which is a leg of a perpendicular line standing from the center of gravity GP of the head to the face. The test method is as follows.

<Torque Breaking Strength Test> As shown in FIG. 8, the club head H of the test club G is fixed immovably with the first jig M1 and 50 mm from the rear end of the shaft 1 from which the grip is removed. Is gripped by the second jig M2, and the second jig M2 is twisted around the center line of the shaft 1 with a torque of 20 (N · m) to separate the bonded portion between the shaft 1 and the head. And so on. Those that came off (including destruction) were evaluated as x, and those that did not come out were evaluated as o.

<Durability> A test club was attached to a swing robot (manufactured by Miyamae) and the head speed was 50 m /
If the ball is hit 3,000 times in s, and there is no damage such as "head dropout" or "shaft breakage" during that time, "○". If damage occurs, the number of hits up to that point is divided by 3000. And it was indicated by an index multiplied by 100. In order to secure the strength required in actual use by an actual golfer, 200
0 times or more (67 or more in index), more preferably 25
It is desirable to be able to withstand hits of 00 or more (83 or more in the index).

<Feeling Test> The golfer's feeling was examined for ease of swinging and holding feeling. Table 1 shows the test results, and Table 2 shows the specifications of the club head.

[0044]

[Table 1]

[0045]

[Table 2]

As a result of the test, the club according to the embodiment has the torque breaking strength and durability enough to withstand practical use, and maintains the feeling at the time of holding it at the same level as before, while maintaining the feeling of the bonded portion. It was confirmed that the axial length could be reduced (the hosel was shortened), and that the sweet spot height of the head was reduced. In Examples 1 and 5, the shaft was bent around the protruding portion in the durability test. This is probably because the length La2 of the protruding portion was small. Further, in Example 4 and Comparative Example 2, it is considered that the head came off due to the decrease in the bonding area. Further, in Comparative Example 2, the shaft was broken around the protruding portion in the torque breakdown test.

Next, a plurality of shafts were prototyped according to the specifications based on Table 3, and an iron-type club head was fixed to the shafts with an adhesive, and the torque rupture strength, durability, and ease of holding of the bonded portion were determined. A test similar to the above was conducted for ease of swinging. The prepreg used for the shaft was a PAN-based carbon fiber as a reinforcing fiber for the main prepreg, and the auxiliary prepreg was a pitch-based carbon fiber.
In addition, each shaft has a thickness of 2.5 to 4.2 m at the same diameter.
m, the thickness of the first tapered portion was 1.0 to 2.5 mm, and the thickness of the second tapered portion was 0.7 to 1.0 mm.

In the club head, the sweet spot height changes due to the difference in the length of the shaft mounting hole (length of the hosel) of the head, and the specifications are shown in Table 4. Further, by changing the shape and thickness of the head, changes in head weight and head volume due to the difference in the length of the shaft mounting hole of each club head are eliminated. Table 3 shows the test results, and Table 4 shows the specifications of the club head.

[0049]

[Table 3]

[0050]

[Table 4]

As a result of the test, the club of the example had sufficient torque breaking strength and durability enough to withstand practical use, and while maintaining the feeling when held, it was almost the same as before. This makes it possible to reduce the axial length of the bonding portion. Thereby, the sweet spot height of the head can be reduced.

Next, for the wood-type golf club and the iron-type golf club using the shaft of the present embodiment, only the outer diameter of the equal-diameter portion is changed. ) Was examined for iron type. The test contents are as follows.

<Flight Distance Performance> A test club (wood type) was attached to a swing robot (manufactured by Miyama), and five balls were hit at a head speed of 45 m / s, and the flight distance (carry + run) was measured. The average value was measured. When the flight distance in the second embodiment is X, the flight distance is Was evaluated.

<Directional Performance> A test robot (iron type) was attached to a swing robot (Miyamae Co., Ltd.), and five balls were hit at a head speed of 37 m / s. Those within “以内” were evaluated within ± 3 to 6 yards as “△” and others were evaluated as “×”. Tables 5 and 6 show the test results.

[0055]

[Table 5]

[0056]

[Table 6]

As a result of the test, it can be confirmed that in the case of the wood type, the flight distance performance and the durability are improved in a well-balanced manner when the outer diameter Da of the equal diameter portion is in the range of 9.0 to 13.0 mm. In the case of the iron type, the outer diameter Da of the equal diameter portion is 10.
It can be confirmed that the directional performance is improved in the range of 0 to 15.0 mm, more preferably 11 to 13.5 mm.

[0058]

As described above, in the golf club shaft of the present invention and the golf club using the same, the tip of the shaft inserted into the shaft mounting hole formed in the hosel of the club head. However, even if the hosel is shortened by having a substantially constant outer diameter and an equal diameter portion extending from the front end to the rear end side and having a large outer diameter of 9.0 to 15.0 mm. It is possible to secure a sufficient bonding area. Therefore, such a shaft or golf club can shorten the hosel of the club head while preventing the head from coming off, so that the reduced weight of the hosel can be distributed to other parts of the club head. The degree of freedom in the weight distribution design of the head can be further increased.

A first tapered portion connected to the large-diameter equal-diameter portion and having an outer diameter gradually decreasing toward the rear end;
By including a second taper portion connected to the first taper portion and having an outer diameter gradually increasing toward the rear end side, the rigidity of the shaft is increased by a large-diameter equal-diameter portion. 2
And the rigidity of the tip end of the shaft is effectively prevented from becoming excessive, and for example, the loss of the flight distance is suppressed.

The axial length of the equal diameter portion is 50.0 to
When it is restricted to the range of 100.0 mm, the strength or balance of the shaft can be improved more reliably and optimally while suppressing the increase in weight of the shaft. Further, by reinforcing the equal-diameter portion of the shaft with a fiber-reinforced resin sheet containing reinforcing fibers having a tensile modulus of 15000 kgf / mm ² or less, the thickness of the shaft can be reduced without excessively increasing the rigidity of the tip portion of the shaft. Can be increased, which helps to improve the durability and the like of the shaft.

The equal-diameter portion is formed so as to have a head portion by restricting the length in the axial direction of the bonding portion bonded to the shaft mounting hole of the hosel via an adhesive and the protruding portion protruding from the shaft mounting hole. The hosel can be shortened while improving the adhesion of the shaft, and the breakage of the shaft can be reliably prevented.

Also, by appropriately setting the outer diameter Da of the equal diameter portion in accordance with each of the wood type and iron type golf clubs, in the wood type golf club, the bending feeling of the tip portion of the shaft is ensured. In the case of an iron-type golf club, the sense of firmness at the tip of the shaft can be ensured and the directionality of the hit ball can be stabilized.

[Brief description of the drawings]

FIG. 1 is an overall plan view of a shaft showing an embodiment of the present invention.

2 (a) is a partially enlarged view of the tip side, FIG. 2 (b) is an XX end view thereof, and FIG. 2 (c) is a YY and ZZ end view thereof.

FIG. 3 is a partial plan view of a shaft illustrating a gradient of a tapered portion.

FIG. 4 is a plan view illustrating a prepreg.

FIGS. 5A to 5C are schematic sectional views of a shaft.

FIG. 6 is a partial sectional view of a wood type golf club.

FIG. 7 is a partial sectional view of an iron type golf club.

FIG. 8 is a diagram illustrating a torque fracture strength test of a golf club.

FIG. 9 is a diagram illustrating a sweet spot height.

FIG. 10 is a front view of the iron type golf club,
(A) shows an inner hosel type and (b) shows an over hosel type.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shaft 2 Equal diameter part 3 1st taper part 4 2nd taper part 5 Crown part 6 Side part 7 Sole part 9 Horsel 10 Shaft mounting hole G Golf club H Club head

Claims (7)

[Claims] An inner hosel type golf club shaft having a tip inserted into a shaft mounting hole formed in a hosel of a club head and a grip attached to a rear end, wherein the shaft has a substantially constant outer diameter. An equal diameter portion extending from the front end to the rear end side, a first tapered portion connected to the equal diameter portion and having an outer diameter gradually decreasing toward the rear end side, and connected to the first tapered portion and outside A shaft for a golf club, comprising: a second tapered portion having a diameter gradually increasing toward a rear end side; and an outer diameter of the equal diameter portion is 9.0 to 15.0 mm. 2. The equal-diameter portion has an axial length of 50.0 to 1
2. The golf club shaft according to claim 1, wherein the diameter is 00.0 mm. 3. The equal diameter portion has a tensile modulus of 15,000 kg.
3. The golf club shaft according to claim 1, wherein the shaft is reinforced with a fiber reinforced resin containing a reinforcing fiber of f / mm ² or less. 4. The golf club shaft according to claim 1, wherein the equal diameter portion is inserted into and adhered to a shaft mounting hole of the hosel, and is attached to the rear end of the golf club shaft. A golf club with a grip attached. 5. The constant diameter portion includes an adhesive portion bonded to the shaft mounting hole via an adhesive, and a protruding portion protruding from the shaft mounting hole, and has a length in the axial direction of the bonding portion. 21.5 to 36.0 mm, and the axial length of the protruding portion is 20 to 50 mm
The golf club according to claim 4, wherein: 6. The equal diameter portion has an outer diameter of 9.0 to 13.0 mm.
And the axial length of the bonding portion is 25.0 to 3
6.0 mm, and the protruding portion has an axial length of 2 mm.
The wood-type golf club according to claim 5, wherein the thickness is 0 to 50 mm. 7. The equal diameter portion has an outer diameter of 10.0 to 15.0.
mm, and the axial length of the bonding portion is 21.5 to 3
2.0 mm, and the axial length of the protruding portion is 2 mm.
6. The iron-type golf club according to claim 5, wherein the diameter is 0 to 50 mm.