JP2020146139A - Golf club shaft - Google Patents

Abstract

To obtain a golf club which easily enables a hit ball to fly in a desired direction, and enables the hit golf ball to attain sufficient distance.SOLUTION: A shaft 10 is set in such a way that a full length is 940-1,168 mm, an external diameter of a tip 12 is 10.0-11.5 mm, an external diameter of a bat 14 is 15-16 mm, a weight thereof is 50 g or less, and a shaft torque is 3.5°-5.5°. A ratio of a bending rigidity value of the shaft 10 and a ratio of a twist rigidity value thereof at a position of 1/2 of a full length L of the shaft 10 to a bending rigidity value and twist rigidity value at the end of the bat are each 0.4 or less, and s 0.5 or more. Furthermore, between an average bending rigidity value EI400 and an average twist rigidity value GIp400 in a 400 mm position from a distal end of the tip 12 to the bat 14, and an average bending rigidity value EIall, and an average twist rigidity value GIpall of the whole shaft 10, EI400/EIall of 0.60-0.75, and GIp400/GIpall of 0.60 or more are satisfied.SELECTED DRAWING: Figure 1

Description

The present invention relates to a golf club shaft for providing a head and a grip to obtain a golf club.

As a shaft for golf clubs (hereinafter, also simply referred to as "shaft"), for example, a shaft disclosed in Patent Document 1 is known. In this shaft, the weight is reduced while increasing the outer diameter over the entire axis direction (total length). According to a golf club obtained by using such a shaft, the directionality of the hit ball is improved due to the large torsional rigidity of the shaft, and the swing speed is increased due to the light weight, so that the flight distance of the ball is increased. Is expected to be longer.

Japanese Unexamined Patent Publication No. 11-319170

When the outer diameter of the shaft is increased over the entire length as described in Patent Document 1, the outer diameter of the bat is inevitably also increased. Along with this, the outer diameter of the grip provided on the bat also increases. For this reason, there is a concern that the movement of the hand of the player holding the grip is restricted. When such a situation occurs, it becomes difficult to make an accurate and fast swing, and thus the directionality and flight distance of the ball become unsatisfactory.

Further, in a shaft having a large outer diameter, not only the torsional rigidity but also the bending rigidity becomes large, so that the tip side may not be sufficiently bent. In this case, the trajectory of the ball becomes low, which causes a decrease in the flight distance. Moreover, with a shaft having a large outer diameter, the bending rigidity from the central portion to the bat increases, so that the player feels hardness when swinging. That is, the feeling is lowered.

The present invention has been made to solve the above-mentioned problems, and the golf has a good directionality of the hit ball, can avoid a decrease in the feeling at the time of swing, and has a sufficient flight distance. It is an object of the present invention to provide a shaft for a golf club from which a club can be obtained.

In order to achieve the above object, according to one embodiment of the present invention, in a golf club shaft composed of a fiber reinforced resin layer and having an outer diameter increasing from the tip to the bat, the bat is formed from the tip of the tip. The total length up to the tip of the is 940 to 1168 mm,
The outer diameter of the tip is 10.0 to 11.5 mm.
The outer diameter of the bat is 15 to 16 mm.
Moreover, the weight is 50 g or less, the shaft torque is 3.5 ° to 5.5 °, and the shaft torque is 3.5 ° to 5.5 °.
The ratio of the flexural rigidity value at the position of 1/2 of the total length to the bending rigidity value of the end of the bat, and the ratio of the torsional rigidity value at the position of 1/2 of the total length to the torsional rigidity value of the end of the bat , 0.4 or less and 0.5 or more, respectively.
Further, the average flexural rigidity value from the tip of the tip to the position 400 mm toward the bat is EI ₄₀₀ , the average torsional rigidity value is GI _p400 , and the overall average bending rigidity value of the golf club shaft is EI _all , average. When the torsional rigidity value is GI _pall , a shaft for a golf club that simultaneously satisfies the following equations (1) and (2) is provided.
0.60 ≤ EI ₄₀₀ / EI _all ≤ 0.75 ... (1)
GI _p400 / GI _pall ≧ 0.60… (2)

According to the present invention, the outer diameter of the tip is set to be large and the shaft torque is set to be small as compared with a general golf club shaft, and a lightweight golf club shaft is configured. Moreover, since the EI ₄₀₀ / EI _all is in the range of 0.60 to 0.75, the golf club shaft exhibits good flexibility. In other words, it bends enough. Therefore, the launch angle when the ball is hit becomes large. Therefore, it is avoided that the trajectory is lowered and the flight distance is increased.

Moreover, since the GI _p400 / GI _pall is 0.60 or more, it becomes easy for the player to fly the hit ball in a desired direction. That is, the directionality of the ball is good. Further, since the bending rigidity of the central portion in the length direction is small, it is possible to prevent the player from feeling stiff during the swing.

For the above reasons, when hitting a ball with a golf club obtained by using this golf club shaft, it is avoided that the trajectory is lowered due to a large launch angle, and as a result, the flight distance is increased. .. In addition, it is easy to fly the ball in the direction intended by the player (the directionality is good). In addition, the feeling is prevented from deteriorating.

It is a schematic whole side view of the shaft for a golf club which concerns on embodiment of this invention. It is a developed view which showed the prepreg sheet (fiber reinforced resin material) which constitutes the shaft for a golf club of FIG. These are various physical property values of the shafts of Examples 1 to 4 before and after cutting. It is an evaluation result of various tests of the golf club obtained by using the shaft of Examples and Comparative Examples 1 to 4.

Hereinafter, preferred embodiments of the golf club shaft according to the present invention will be given and will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic overall side view of a shaft 10 (a shaft for a golf club) according to the present embodiment. One end of the shaft 10 is a tip 12 and the other end is a butt 14. As shown by a virtual line in FIG. 1, a head 16 is attached to the tip 12 and a grip 18 is attached to the bat 14. This constitutes a golf club.

A hosel is provided on the head 16, and the tip 12 is inserted and fixed in the hosel. As a result, the head 16 is attached to the shaft 10. The head 16 may be an iron crab head, a wood crab head, or a utility head. Further, by appropriately setting the total length L of the shaft 10, it can be used as a wood club for a driver or the like, or as a utility club.

The shaft 10 is composed of, for example, a hollow cylinder whose outer diameter gradually increases as it goes from the tip 12 to the butt 14. The outer diameter of the tip 12 is set to 10.0 to 11.5 mm. The outer diameter (10.0 to 11.5 mm) of the tip 12 in the present embodiment is larger than that of the tip in a general shaft.

On the other hand, the outer diameter of the bat 14 is set within the range of 15 to 16 mm. The outer diameter of the bat 14 is set larger than that of the tip 12.

The length from the tip of the tip 12 to the tip of the butt 14, in other words, the total length L along the axial direction of the shaft 10 is set to 940 to 1168 mm, preferably 940 to 1105 mm. In particular, the shaft 10 having a total length L in the range of 940 to 1105 mm is suitable as a shaft for a utility club.

Further, the mass of the shaft 10 is set to 50 g or less. That is, the mass of the shaft 10 is smaller than that of a general shaft. Further, the shaft torque of the shaft 10 is set to 3.5 ° to 5.5 °. Here, the shaft torque positions and fixes the butt 14 of the shaft 10, and attaches a rod member having a length of 1 foot to the chip 12 extending in a direction orthogonal to the shaft 10, and in this state, the rod member of the rod member. It is defined as the rotation angle when twisted with a 1-pound weight attached to the tip. That is, the smaller the shaft torque value, the greater the torsional rigidity.

As described above, the shaft 10 is lightweight even though the outer diameter of the tip 12 is large and the shaft torque is small as compared with the conventional technique.

Here, in the shaft 10, the bending rigidity at the position halved of the total length L (in other words, the intermediate position in the longitudinal direction of the shaft 10) is EI _center , the torsional rigidity is GI _pcenter , and the bending rigidity at the tip of the butt 14 is EI. _Assuming that the _butt and the torsional rigidity are GI _pbutts , the flexural rigidity ratios EI _center / EI _butt and the torsional rigidity GI _pcenter / GI _pbutt are 0.4 or less and 0.5 or more, respectively. By setting the flexural rigidity of the shaft 10 at the intermediate position in the longitudinal direction to be small in this way, it is possible to feel the flexibility when the player swings the golf club configured including the shaft 10. That is, the feeling at the time of swing becomes good.

Further, as shown in FIG. 1, the average bending rigidity value from the tip of the tip 12 to the position 400 mm toward the butt 14 is EI ₄₀₀ , the average torsional rigidity value is GI _p400 , and the overall average bending rigidity value of the shaft 10 is set. When EI _all and the average torsional rigidity value are GI _pall , EI ₄₀₀ / EI _all is 0.60 or more and 0.75 or less, and GI _p400 / GI _pall is 0.60 or more on the shaft 10. That is, the following equations (1) and (2) are satisfied at the same time.
0.60 ≤ EI ₄₀₀ / EI _all ≤ 0.75 ... (1)
GI _p400 / GI _pall ≧ 0.60… (2)

As described above, in the present embodiment, not only the partial bending rigidity value on the chip 12 side is set small and the torsional rigidity value is increased, but also the bending rigidity value and the torsional rigidity value are distributed over the entire shaft 10. As a result, the ratio of the partial average rigidity value on the chip 12 side to the overall average rigidity value is appropriately set. Then, based on the fact that the EI ₄₀₀ / EI _all is 0.60 or more and 0.75 or less, the shaft 10 is sufficiently bent. Therefore, it is avoided that the trajectory of the hit ball is lowered. Further, since the GI _p400 / GI _pall is 0.60 or more, it becomes easy to fly the hit ball in the direction intended by the player. In other words, the direction of the ball is good.

Such a shaft 10 can be obtained, for example, by forming a fiber reinforced resin layer from a plurality of prepreg sheets (fiber reinforced resin materials) as shown in FIG. Typical examples of the reinforcing fibers and the matrix resin of the prepreg sheet include carbon fibers and thermosetting epoxy resins, respectively.

The shaft 10 includes a first full-length bias layer and a second full-length bias layer formed by winding prepreg sheets 20a and 20b as a fiber-reinforced resin layer extending (over the entire length) from the tip of the tip 12 to the tip of the butt 14. It includes a first full length straight layer and a second full length straight layer formed by winding prepreg sheets 22a and 22b. In the prepreg sheets 20a and 20b forming the first full-length bias layer and the second full-length bias layer, the orientation direction of the reinforcing fibers is inclined with respect to the axial direction of the shaft 10. The diagonal lines in FIG. 2 indicate the orientation direction of the reinforcing fibers, and the same applies to other prepreg sheets.

FIG. 2 illustrates a case where the tilt angle of the prepreg sheet 20a is + 45 ° and the tilt angle of the prepreg sheet 20b is −45 °, but the tilt angle is not particularly limited to this, for example, ±. It can be set to an appropriate angle within the range of 25 ° to ± 65 °.

On the other hand, in the prepreg sheets 22a and 22b forming the first full-length straight layer and the second full-length straight layer, the reinforcing fibers are oriented along the axial direction of the shaft 10. That is, the orientation direction of the reinforcing fibers is substantially parallel to the axial direction of the shaft 10. For convenience of explanation, the inclination angle of the reinforcing fibers with respect to the axial direction of the shaft 10 at this time is expressed as 0 °.

As described above, the first and second full length bias layers and the first and second full length straight layers are all layers extending from the tip of the tip 12 to the tip of the butt 14. Then, in the first and second full length bias layers, the reinforcing fibers are oriented in a direction inclined with respect to the axial direction of the shaft 10, while in the first and second full length straight layers, the reinforcing fibers are oriented in the shaft 10. It is oriented along the axial direction.

The winding order of the first and second full length bias layers and the first and second full length straight layers is not particularly limited, but for example, the first full length bias layer, the second full length bias layer, and the first. The 1st full length straight layer and the 2nd full length straight layer can be in this order from the inside. The full-length straight layer may be the outer peripheral side of the full-length bias layer.

In this case, the shaft 10 further includes a full-length hoop layer as a fiber-reinforced resin layer over the entire length. The full-length hoop layer is, for example, the outermost layer located outside the first and second full-length straight layers. In the prepreg sheet 24 forming the full-length hoop layer, the reinforcing fibers are oriented in a direction substantially orthogonal to the axial direction of the shaft 10. For convenience of explanation, the inclination angle of the reinforcing fibers with respect to the axial direction of the shaft 10 at this time is expressed as 90 °.

The fiber reinforced resin layer on the chip 12 side is provided at one end of the first and second full length bias layers and the first and second full length straight layers in order to increase the outer diameter of the chip 12 and the torsional rigidity. Further included is a chip reinforcement layer. The chip reinforcing layer forms the chip 12 together with one ends of the first and second full length bias layers and the first and second full length straight layers.

The chip reinforcing layers include a first chip reinforcing bias layer and a second chip reinforcing bias layer formed by winding prepreg sheets 26a and 26b, and a first chip reinforcing straight layer and a second chip formed by winding prepreg sheets 28a and 28b. It is composed of a reinforcing straight layer and a chip reinforcing hoop layer formed by winding a prepreg sheet 30.

In the prepreg sheets 26a and 26b (first and second tip reinforcing bias layers), the reinforcing fibers are oriented in a direction inclined with respect to the axial direction of the shaft 10. On the other hand, in the prepreg sheets 28a and 28b (first and second tip reinforcing straight layers), the reinforcing fibers are oriented substantially parallel to the axial direction of the shaft 10, and the inclination angle is 0 °. Further, in the prepreg sheet 30 forming the tip reinforcing hoop layer, the reinforcing fibers are oriented in a direction substantially orthogonal to the axial direction of the shaft 10. That is, the inclination angle is 90 °.

When the tip reinforcing layer is configured to include the first and second tip reinforcing bias layers, the first and second tip reinforcing straight layers, and the tip reinforcing hoop layers as described above, for example, the first and second tip reinforcements are formed. The bias layer may be inside the first and second full length bias layers, and the first and second tip reinforcing straight layers and the tip reinforcing hoop layers may be surrounded by the outer periphery of the full length hoop layer in this order.

The shaft 10 further includes a butt reinforcing straight layer (butt reinforcing layer) formed by winding the prepreg sheet 32. The butt reinforcing straight layer covers the parts of the first and second full length bias layers and the first and second full length straight layers other than the parts covered by the chip reinforcing layer, and the ends thereof are the first and second full length biases. The bat 14 is formed with the layers and the ends of the first and second full length straight layers. That is, the butt reinforcing straight layer does not overlap with any of the first and second chip reinforcing bias layers, the first and second chip reinforcing straight layers, and the chip reinforcing hoop layers, which are the chip reinforcing layers. Further, the butt reinforcing straight layer is inserted between the second full length straight layer and the full length hoop layer, for example.

The bending rigidity of the tip 12 and the butt 14 is appropriately adjusted by the tip reinforcing layer and the butt reinforcing straight layer. In the above, as the butt reinforcing layer, a butt reinforcing straight layer in which the reinforcing fibers are oriented along the axial direction of the shaft 10 is adopted, but the present invention is not particularly limited to this, and the reinforcing fibers are the shaft 10. A butt reinforcing hoop layer inclined with respect to the axial direction may be adopted.

As described above, in the present embodiment, in the fiber reinforced resin layer, the prepreg sheets 20a, 20b, 22a, 22b, 24, 26a, 26b, 28a, 28b, 30, 32 are wound with a predetermined number of plies. It is formed by combining a plurality of layers such as a full-length bias layer, a full-length straight layer, a chip reinforcing layer, and a butt reinforcing layer. In this case, the materials of the prepreg sheets 20a, 20b, 22a, 22b, 24, 26a, 26b, 28a, 28b, 30, 32, the orientation direction of the reinforcing fibers, the winding position, the winding order, the number of windings, etc. are appropriately set. By doing so, the physical properties of the shaft 10 become as described above. In other words, by combining the plurality of layers, it becomes easy to obtain the shaft 10 having the above-mentioned physical properties.

For example, the shaft 10 winds the above-mentioned prepreg sheets 26a, 26b, 20a, 20b, 22a, 22b, 32, 24, 28a, 30, 28b around the mandrel in this order from the inner peripheral side, pressurizes and pressurizes the shaft 10. It can be produced by heating and curing. After that, the mandrel is pulled out from the shaft 10. The shaft 10 having the above-mentioned physical properties can be obtained by appropriately setting the type of the prepreg sheet, the orientation direction of the reinforcing fibers, the winding position, the winding order, the number of windings, and the like.

The prepreg sheets 26a, 26b, 20a, 20b, 22a, 22b, 32, 24, 28a, 30, 28b shown in FIG. 2 have a predetermined number of plies so that the upper side of FIG. 2 is the inner side and the lower side is the outer side. The shaft 10 was obtained by winding it around a mandrel, pressurizing and heating it, and then separating it from the mandrel. That is, the shaft 10 includes a first and second chip reinforcing bias layer, a first and second full length bias layer, a first and second full length straight layer, a butt reinforcing straight layer, a full length hoop layer, and a first chip reinforcing straight layer. The chip reinforcing hoop layer and the second chip reinforcing straight layer are provided in this order from the inside.

The shaft 10 obtained as described above had a total length of 1080 mm, an outer diameter of the tip 12 of 11.0 mm, an outer diameter of the butt 14 of 15.3 mm, a mass of 43 g, and a shaft torque of 5.1 °. .. Further, the bending rigidity EI _center at the position of 1/2 (middle of the total length L) of the total length L, and torsional rigidity GI _{P center,} the bending rigidity EI _butt at the tip of the bat 14, when the torsional rigidity and _GI pbutt, EI _center / EI _butt and GI _pcenter / GI _pbutt are 0.34 and 0.56, respectively, and the ratio of average flexural rigidity (EI ₄₀₀ / EI _all ) is 0.68 and the ratio of average torsional rigidity (EI ₄₀₀ / EI _all ) is 0.68. GI _p400 / GI _pall ) was 0.66.

The shaft 10 is cut from the tip on the side where the chip reinforcing straight layer is formed to 25.4 mm toward the side where the butt reinforcing straight layer is formed, while the tip reinforcing layer is cut from the tip on the side where the butt reinforcing straight layer is formed. It was cut up to 54.6 mm toward the formed side to make the length 1000 mm. At this time, the outer diameter of the tip 12, the outer diameter of the butt 14, the mass, the shaft torque, the EI ₄₀₀ / EI _all , and the GI _p400 / GI _pall are 11.0 mm, 15.3 mm, 39.8 g, and 4.6, respectively. °, 0.70, 0.70. This is an example.

That is, before and after cutting, the shaft 10 of the embodiment has a total length L within the range of 940 to 1168 mm, the outer diameter of the chip 12 within the range of 10.0 to 11.5 mm, and the outer diameter of the butt 14 within the range of 15 to 16 mm. Within the range, weight is 50 g or less, shaft torque is within the range of 3.5 ° to 5.5 °, EI ₄₀₀ / EI _all is within the range of 0.60 to _0.75 , GI _p400 / GI _pall is 0.60. That is all.

On the other hand, the outer diameters of the chips before and after cutting are both 11.5 mm, the shaft torques before and after cutting are 3.0 ° and 2.7 °, respectively, and the EI ₄₀₀ / EI _all before and after cutting are 0.58 and 0. A shaft of 61 was produced. This is referred to as Comparative Example 1.

The outer diameters of the chips before and after cutting are both 9.0 mm, the EI ₄₀₀ / EI _all before and after cutting are 0.53 and 0.56, respectively, and the GI _p400 / GI _pall before and after cutting are 0.46 and 0.50, respectively. A shaft was produced. This is referred to as Comparative Example 2.

Further, a shaft having an outer diameter of 11.5 mm before and after cutting, a shaft torque of 3.2 ° and 2.9 ° before and after cutting, and an EI ₄₀₀ / EI _all of 0.88 before and after cutting were produced. did. This is referred to as Comparative Example 3.

Then, a shaft having an outer diameter of the tip before and after cutting of 9.0 mm was produced. This is referred to as Comparative Example 4.

The physical properties of the shaft 10 of the above examples and the shafts of Comparative Examples 1 to 4 before and after cutting are collectively shown in FIG.

A utility head having a loft angle of 21 ° is attached to the tip of each of the cut shafts 10 of Examples and the cut shafts of Comparative Examples 1 to 4, and a grip is attached to the bat to attach a golf club. Made. Using this golf club, a tester hit five balls, measured the initial velocity, launch angle, and flight distance of the balls, and determined the deviation from the target direction and the variation in the left-right direction. In addition, the tester swung and evaluated the feeling at that time.

The results are summarized in FIG. Regarding the deviation with respect to the target direction, the average value of 5 times is shown as + (plus) when moving to the right with respect to the target direction and-(minus) when moving to the left. The variation in the left-right direction is the distance between the time when the ball flies to the rightmost and the time when the ball flies to the leftmost of the five hits.

From FIG. 4, it can be seen that in the golf club using the shaft 10 of the embodiment, the launch angle is large, and as a result, the flight distance is large, and the ball can be hit in the target direction with little variation in the left-right direction. Moreover, the feeling at the time of swing is evaluated to be superior (good, ○) to that of a general golf club.

On the other hand, first, in the golf club using the shaft of Comparative Example 1, the feeling at the time of swing is equivalent to that of a general golf club (usually Δ). Further, in the golf club using the shafts of Comparative Examples 2 to 4, the deviation from the target direction is large. This means that it is not easy for the player to fly the ball in the desired direction.

Further, the golf clubs using the shafts of Comparative Examples 3 and 4 all have a small launch angle, and therefore the flight distance is small. In addition, the feeling at the time of swing was inferior (poor, ×) and normal (Δ) as compared with general golf clubs, respectively.

From the above results, it is clear that the golf club using the shaft 10 of the embodiment has a good ball directionality and a sufficient flight distance can be obtained.

10 ... Golf club shaft 12 ... Chip 14 ... Bat 16 ... Head 18 ... Grips 20a, 20b, 22a, 22b, 24, 26a, 26b, 28a, 28b, 30, 32 ... Prepreg seat

Claims (5)

In a golf club shaft, which consists of a fiber reinforced resin layer and whose outer diameter increases from the tip to the bat.
The total length from the tip of the tip to the tip of the bat is 940 to 1168 mm.
The outer diameter of the tip is 10.0 to 11.5 mm.
The outer diameter of the bat is 15 to 16 mm.
Moreover, the weight is 50 g or less, the shaft torque is 3.5 ° to 5.5 °, and the shaft torque is 3.5 ° to 5.5 °.
The ratio of the flexural rigidity value at the position of 1/2 of the total length to the bending rigidity value of the end of the bat, and the ratio of the torsional rigidity value at the position of 1/2 of the total length to the torsional rigidity value of the end of the bat , 0.4 or less and 0.5 or more, respectively.
Further, the average flexural rigidity value from the tip of the tip to the position 400 mm toward the bat is EI ₄₀₀ , the average torsional rigidity value is GI _p400 , and the overall average bending rigidity value of the golf club shaft is EI _all . when the torsional rigidity value _{GI pall,} the following equation (1), a shaft for a golf club that satisfies simultaneously (2).
0.60 ≤ EI ₄₀₀ / EI _all ≤ 0.75 ... (1)
_{GI p400 / GI pall ≧ 0.60 ...} (2) In the shaft according to claim 1,
The fiber reinforced resin layer is at least
A full-length bias layer extending from the tip of the tip to the tip of the bat and in which the reinforcing fibers are oriented in a direction inclined with respect to the axial direction of the golf club shaft.
A full-length straight layer extending from the tip of the tip to the tip of the bat and having reinforcing fibers oriented along the axial direction of the golf club shaft.
The chip reinforcing layer forming the chip and
A butt reinforcing layer provided on a portion of the full length bias layer and the full length straight layer other than the portion where the tip reinforcing layer is provided to form the butt,
Shafts for golf clubs including. In the shaft according to claim 2,
In the bat reinforcing layer, a golf club shaft in which reinforcing fibers are oriented along the axial direction of the golf club shaft. In the shaft according to claim 2 or 3.
The chip reinforcing layer is
A tip reinforcing bias layer in which the reinforcing fibers are oriented in a direction in which the reinforcing fibers are inclined with respect to the axial direction of the golf club shaft,
A chip reinforcing straight layer in which the reinforcing fibers are oriented along the axial direction of the golf club shaft, and
A chip reinforcing hoop layer in which the reinforcing fibers are oriented in a direction substantially orthogonal to the axial direction of the golf club shaft, and
Shafts for golf clubs including. In the shaft according to any one of claims 2 to 4.
Golf including a full-length hoop layer in which the fiber-reinforced resin layer extends from the tip of the tip to the tip of the bat and the reinforcing fibers are oriented in a direction substantially orthogonal to the axial direction of the golf club shaft. Club shaft.

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