JP5542612B2 - Golf club shaft set and iron set - Google Patents

Description

  The present invention relates to a golf club shaft set and an iron set used for a golf club, for example.

For example, in Patent Document 1, as the length of the shaft increases, the length of the intermediate region is increased, and the tone is changed while the amount of change in bending rigidity is decreased, so that a function required according to the club number is obtained. Give to each club.
For example, in Patent Document 2, even if the golfer feels the bending of the shaft, the bending rigidity change amount of the portion where the shaft suddenly becomes softer, the longer the club is, the shorter the club is, and the club length is different. The shaft set has a bending stiffness distribution that allows easy swing timing.

JP-A-10-225537 JP 2010-154875 A

In the case of Patent Document 1, a plurality of different mandrels are prepared for adjusting the length of the intermediate region, and the outer diameter and inner diameter are adjusted (thickness adjustment) for adjusting the bending rigidity of the intermediate region. The variability tends to increase.
In the case of Patent Document 2, when this type of shaft is formed from a laminate of fiber reinforced resin prepregs, it is produced by combining various prepregs of fiber direction straight layer type, biased layer type, full length type, and auxiliary type shorter than the full length. doing. However, for each count, the combination of the full length type and the short auxiliary type tends to cause variations in manufacturing accuracy.

  The present invention has been made to solve such a problem, and in adjusting the bending rigidity, a golf club shaft set and an iron capable of simplifying a laminated structure and reducing variations in manufacturing accuracy. Is to provide a set.

In order to solve the above problems, according to the present invention, the front region of the axial front portion and the rear region of the rear portion in the axial direction, and a taper-shaped step difference taper toward the front portion in the axial direction between them. A shaft that is formed by winding a prepreg in which a reinforcing fiber is impregnated with a synthetic resin is wound around a tapered core metal having an intermediate region to be connected to each other, and a shaft whose overall length becomes shorter as the golf club count increases The shaft set for a golf club according to claim 1, wherein each of the numbered shafts has the step on the front region side of the core metal, and the outer surface of the intermediate region is flush with the outer surface of the intermediate region. a front region formed by a prepreg comprising a shaped portion to be a part-side outer diameter adjustment layer wound front region of the metal core, the step in the rear area side of the core metal Comb, a rear region formed by winding a prepreg comprising a peripheral surface of a shape portion to be the rear side outer diameter adjustment layer to the outer peripheral surface flush of the rear area of the central region in the rear region of the core metal , anda central region formed between said front region and said winding a prepreg on the outer peripheral front region and said rear region of said rear region with along the intermediate region of the core metal, the The bending stiffness of the front region and the rear region is set to be equal to or higher than the previous count as the golf club count increases, the bending stiffness of the middle region is set to be the same for each count, and The present invention is characterized in that a change in bending rigidity generated in the step is alleviated by a flush outer peripheral surface.
It is preferable that the weight of the rear region is made equal to or larger than that of the front count as the count of the golf club increases.
It is preferable that the front region and the rear region are formed by winding a plurality of prepregs, and at least one identical prepreg is used in adjacent counts.
At least one of the front region and the rear region has at least three reinforcing prepregs along the intermediate region of the core metal and separately from the prepreg wound around the outer periphery of the front region and the rear region. Is preferred.
As the prepreg in the front region, one having a fiber elastic modulus of 240 GPa to 400 GPa is used. The fiber elastic modulus increases as the count increases, and the difference in fiber elastic modulus between adjacent counts is in the range of 50 GPa to 110 GPa. The weight of the prepreg in the rear region is 100 g / m ² to 250 g / m ² , and the basis weight increases as the count increases, and the difference in basis weight between adjacent counts increases. Those in the range of 10 g / m ² to 60 g / m ² are preferably used.

According to the present invention, a prepreg is wound around the front region of the core metal to form a front region, and a prepreg is wound around the rear region of the core metal to form a rear region, along the middle region of the core metal and the front Since a shaft can be produced by winding a prepreg around the outer periphery of the front region and the rear region to form a middle region between the front region and the rear region, the laminate structure can be simplified when adjusting the bending rigidity. Variations in manufacturing accuracy can be reduced. In addition, the bending rigidity of the front region and the rear region is the same or higher as the golf club count increases, and the bending rigidity of the middle region is the same for each count. For this reason, the prepreg is wound around the outer periphery of the front region and the rear region, and the bending rigidity of the middle region formed between the front region and the rear region can be lowered as compared with the front region and the rear region. The middle region can be bent most easily during a swing, and the front region and the rear region can be made more difficult to bend than the middle region. In addition, since the configuration of the middle region is shared by each count, the golfer can obtain the same feeling in the middle region during the swing of the golf club (shaft).
Also, the weight of the rear region can be adjusted in the rear region by increasing the weight of the rear region to be the same as or larger than that of the front member as the golf club count increases.
By using at least one identical prepreg in the adjacent count, the feeling of swinging the golf club of that count is close to the sense of swinging the adjacent count golf club. Can provide a flow.
By having at least three reinforcing prepregs, the front region and the rear region can be effectively reinforced and the bending rigidity can be adjusted.
Further, the bending rigidity of the front region can be increased as the count increases by changing the fiber elastic modulus, and the bending rigidity of the rear region can be increased as the count increases by changing the basis weight.

Schematic which shows the golf club which concerns on 1st to 3rd embodiment. Schematic which shows the shaft for golf clubs concerning 1st to 3rd embodiment. BRIEF DESCRIPTION OF THE DRAWINGS Schematic which shows the core metal used when manufacturing the golf club shaft which concerns on 1st Embodiment, the shape of the prepreg sheet with respect to a metal core, the fiber direction of a reinforced fiber, and winding order. 1 is a schematic cross-sectional view of a state in which a prepreg sheet is wound around a core metal when manufacturing a golf club shaft according to a first embodiment. The graph which shows the bending rigidity with respect to the length from the front-end | tip for every count of the shaft for golf clubs concerning 1st Embodiment. Schematic which shows the core metal used when manufacturing the golf club shaft which concerns on 2nd Embodiment, the shape of the prepreg sheet with respect to a metal core, the fiber direction of a reinforced fiber, and winding order. Schematic which shows the core metal used when manufacturing the shaft for golf clubs concerning 3rd Embodiment, the shape of the prepreg sheet with respect to a metal core, the fiber direction of a reinforced fiber, and winding order.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
A first embodiment will be described with reference to FIGS.
Of the golf club sets, the iron set generally includes, for example, a 3 iron to a 9 iron, a pitching wedge, an approach wedge, a sand wedge, and the like. The iron set may include a first iron, a second iron, and other wedges.

  Hereinafter, an example of a set of No. 3 iron to No. 9 iron will be mainly described. However, in the case of calling a set, it should be understood that the No. 1 iron, No. 2 iron, pitching wedge, approach wedge, sand wedge, etc. are appropriately included. is there. In addition, including the pitching wedge, approach wedge, sand wedge, etc., the shaft length L is longer and the loft angle α (see FIG. 1) is smaller, the count is smaller, and the shaft length is shorter and the loft angle α is larger. The golf club 10 and the shaft 12 are defined as being large. In addition, in the “adjacent count”, not only between counts (eg, No. 3 and No. 4, No. 4 and No. 5, such as No. n and (n + 1)), for example, a group of No. 3 and No. 4, for example, This includes the case where a plurality of counts have the same shaft structure, such as between the No. 5 and No. 6 groups.

  As shown in FIG. 1, each golf club 10 of an iron set has a hollow shaft (tubular body made of a fiber reinforced composite material) 12 made of a laminated body of fiber reinforced prepreg sheets, and the shaft 12 in the same manner as each count. The head 14 attached to the small diameter part of the tip (one end, TIP side) 12a (see FIG. 2) and the large diameter part of the rear end (the other end, BUTT side) 12b (see FIG. 2) of the shaft 12 Grip 16. The tip 12a of the shaft 12 shown in FIG. 1 is fixed in a state of being inserted into the hosel 14a of the head 14. In this embodiment, since the golf club set is formed as an iron set, for example, the head 14 and the grip 16 are preferably provided with the same decoration and the like at each count. Of course, it is also preferable that the shaft 12 has the same decoration or the like at each count.

  The loft angle α between the shaft 12 and the face 14b of the head 14 shown in FIG. 1 generally increases by 4 ° between 20 ° and 60 ° as the count increases. Further, the overall length of the shaft 12 is reduced from 0.5 inches (approximately 1.27 cm) as the count increases from, for example, the length L of the shaft 12 of the third iron from 39 inches (approximately 99 cm). As will be described later, the outer diameter of the tip 12a of the shaft 12 is constant regardless of the count because it uses a prepreg sheet having the same thickness, for example, about 9.00 mm to 10.00 mm, and the outer diameter of the rear end 12b will be described later. Since prepreg sheets having different thicknesses are used as described above, for example, the thickness is about 14.20 mm to about 16.50 mm. The outer peripheral surface of the shaft 12 is preferably formed in a tapered shape so as to have an inclination (taper angle) of about 8/1000 to 10/1000 with respect to the central axis C. When the shaft 12 is tapered, the golfer can easily grip the grip due to the grip diameter with respect to the tip diameter of the shaft 12, and the outer diameter can easily exert the grip force.

A cored bar (mandrel) 20 for producing the shaft 12 for each golf club 10 according to the present embodiment shown in FIG. 3 has a common shape for the iron set. The metal core 20 has a first taper portion 22, a second taper portion 24, a third taper portion 26, a fourth taper portion 28, and a fifth taper portion 30 in order from the front end 20a to the rear end 20b. And the straight portion 32, the tip 20a side is formed thinner than the rear end 20b side. Between the 1st taper part 22 and the 2nd taper part 24, between the 2nd taper part 24 and the 3rd taper part 26, between the 3rd taper part 26 and the 4th taper part 28, and the 4th taper part 28 Between the first taper portion 30 and the fifth taper portion 30, and between the fifth taper portion 30 and the straight portion 32, a circumferential displacement portion 23 serving as a boundary for changing the inclination of the outer peripheral surface of the cored bar 20, respectively. 25, 27, 29, and 31 are formed.
The cored bar 20 mainly includes a front region FM on the front end 20a side, a rear region (grip side region) BM on the rear end 20b side, and an intermediate region MM between the front region FM and the rear region BM. It can be divided into three.

Note that the second taper portion 24 has a substantially four times larger inclination than the first taper portion 22 (for example, an inclination of about 8/1000 to 9/1000). The fourth taper portion 28 is a taper that is short and loose (the inclination is small) with respect to the fifth taper portion 30. In other words, the fifth taper portion 30 is a long and steep taper (a large inclination) with respect to the fourth taper portion 28.
Moreover, it is preferable that the 3rd taper part 26 and the 5th taper part 30 are substantially the same inclination. This is because when the prepreg sheet having a certain thickness is placed on the fifth taper portion 30, the outer peripheral surface of the prepreg sheet and the outer peripheral surface of the third taper portion 26 are flush with each other. The inclinations of the third taper portion 26 and the fifth taper portion 30 are substantially the same as the inclination of the outer peripheral surface of the shaft 12 described above.

As shown in FIG. 2, the shaft 12 according to the present embodiment mainly has a front region (head side region) FS to which the head 14 is attached on the front end 12 a side and a grip 16 on the rear end 12 b side. It can be divided into a rear region (grip side region) BS and a middle region MS between the front region FS and the rear region BS.
The front region FS is in a range of about 200 mm to 250 mm from the tip 12 a when the tip 12 a of the shaft 12 is 0, and is preferably about 25% of the total length of the shaft 12. The middle region MS is in a range from about 200 mm to 250 mm to about 350 mm to 400 mm from the tip 12 a of the shaft 12, and is preferably about 25% of the total length of the shaft 12. The rear region BS is in the range of about 350 mm to 400 mm from the tip 12 a of the shaft 12 to about 1000 mm to 1100 mm, and is preferably about 50% of the total length of the shaft 12. That is, when the front end 12a of the shaft 12 is 0% and the rear end 12b is 100%, the front region FS is in a position from 0% to about 25%, and the middle region MS is in a position from about 25% to about 50%. In addition, the rear region BS is at a position of approximately 50% to 100%.

  The shaft 12 is a fiber-reinforced prepreg sheet in which reinforcing fibers are impregnated with a synthetic resin, and the first to third front reinforcing prepreg sheets 42, 44, 46, and the first to third rear reinforcing prepreg sheets 52, 54, 56, first to third main body prepreg sheets 62, 64, 66 and a fourth front reinforcing prepreg sheet 48 are wound around the cored bar 20.

  Carbon fibers are mainly used for the reinforcing fibers of each prepreg sheet, but various fibers such as metal fibers, glass fibers, and aramid fibers may be used. As the matrix resin (synthetic resin) to be impregnated into the reinforcing fiber, either a thermosetting resin or a thermoplastic resin may be used. If it is a thermosetting resin, for example, epoxy, pismaleimide, polyimide, phenol and the like are used. If it is a thermoplastic resin, polyether ether ketone (PEEK), polyether sulfone (PES), polyether imide (PEI), polyphenylene sulfide (PPS), polyamide (PA), polypropylene (PP), etc. are used.

Table 1 below shows the fiber direction of the reinforcing fiber with respect to the core 20 of each prepreg sheet constituting the shaft 12.

  As shown in Table 1, for example, the first to third front reinforcing sheets 42, 44, 46 and the first to third rear reinforcing sheets 52, 54, 56 are each in the fiber direction in the axial direction of the cored bar 20. Is arranged. That is, the first to third front reinforcing sheets 42, 44, 46 and the first to third rear reinforcing sheets 52, 54, 56 are axial length fibers in which the fiber direction is arranged in the axial length direction of the cored bar 20. Layers are used to reinforce and adjust bending stiffness. Similarly to the first to third front reinforcing sheets 42, 44 and 46, the fourth front reinforcing sheet 48 also forms an axial length direction fiber layer in which the fiber direction is arranged in the axial length direction of the core metal 20, and Used for adjustment of diameter, reinforcement and bending rigidity.

The first and second main body sheets 62 and 64 form an inclined fiber layer that is inclined with respect to the axial length direction of the cored bar 20 and is used for adjusting torsional rigidity. In the first main body sheet 62, the reinforcing fibers are inclined with respect to the axial direction, for example, + (plus) 30 degrees to 50 degrees (particularly preferably +45 degrees), and the second main body sheet 64 has the reinforcing fibers with respect to the axial direction. For example, the inclination is − (minus) 30 to 50 degrees (particularly preferably −45 degrees). The 3rd main body sheet | seat 66 forms the axial length direction fiber layer which distributes a fiber direction to the axial length direction of the metal core 20, and is used for adjustment of bending rigidity.
The first and second main body sheets 62 and 64 have a resin amount (fiber content) of 20 to 40 wt% and a tensile elastic modulus of 10 to 400 GPa. As the third main body sheet 66, one having a resin amount (fiber content) of 20 to 40 wt% and a tensile elastic modulus of 10 to 400 GPa is used. However, in the present embodiment, the first to third main body sheets 62, 64, 66 are the same from the 3rd iron to the 9th iron regardless of the count.

Accordingly, the front region FS of the shaft 12 includes first to third front reinforcing prepreg sheets 42, 44, 46, first to third main body prepreg sheets 62, 64, 66, and a fourth front portion. The reinforcing prepreg sheet 48 is formed corresponding to the front region FM of the cored bar 20. The rear region BS of the shaft 12 corresponds to the rear region BM of the cored bar 20 by the first to third rear reinforcing prepreg sheets 52, 54, 56 and the first to third main body prepreg sheets 62, 64, 66. Formed. The middle region MS of the shaft 12 is formed by the first to third main body prepreg sheets 62, 64, 66 corresponding to the intermediate region MM of the cored bar 20.
A prepreg is wound around the front region FM of the core metal 20 to form the front region FS, and a prepreg is wound around the rear region BM of the core metal 20 to form the rear region BS, along the intermediate region MM of the core metal 20. At the same time, the shaft 12 can be produced by winding the prepreg around the outer periphery of the front region FS and the rear region BS to form the middle region MS between the front region FS and the rear region BS. For this reason, when adjusting the bending rigidity of the shaft 12, it is possible to simplify the laminated structure and reduce variations in manufacturing accuracy.

As the first to third front reinforcing sheets 42, 44, and 46 used in the front region FS of each count shaft 12, prepreg sheets having compositions F1 to F3 in Table 2 are appropriately used. The prepreg sheets F1 to F3 in Table 2 have the same basis weight and sheet thickness (or may be substantially the same), and have different fiber elastic moduli. The fiber elastic modulus of F2 is, for example, 50 GPa greater than F1, and F3 is, for example, 110 GPa greater than F2. However, the difference in fiber elastic modulus can be set as appropriate. That is, the difference in fiber elastic modulus between F1 and F2 may be greater than 50 GPa, such as 60 GPa, or may be as small as 40 GPa. The difference in the fiber elastic modulus between F2 and F3 is the same.

As the first to third rear reinforcing sheets 52, 54 and 56 used in the rear region BS of each count shaft 12, prepreg sheets having the compositions B1 to B5 in Table 3 are appropriately used. The prepreg sheets B1 to B4 in Table 3 have the same fiber elastic modulus (or may be substantially the same), and differ in basis weight and sheet thickness. In addition, the fiber elastic modulus of the reinforcing fiber of B5 is larger than the fiber elastic modulus of the reinforcing fiber of B1 to B4. Further, the basis weight and the sheet thickness are B2 larger than B1, B3 larger than B2, B4 larger than B3, and B5 larger than B4, respectively.

  The first to third front reinforcing sheets 42, 44, 46, the first to third rear reinforcing sheets 52, 54, 56, the first to third main body sheets 62, 64, 66, the fourth Each of the front reinforcing sheets 48 has a constant thickness.

  As shown in FIG. 3, the first front reinforcing sheet 42 is wound around the first tapered portion 22 of the core metal 20 and the front portion of the second tapered portion 24. The second and third front reinforcing sheets 44 and 46 are arranged in such a manner that the tips of the second and third front reinforcing sheets 44 and 46 are aligned with the tips of the first front reinforcing sheet 42. It is wound around the outer periphery of. At this time, the second and third front reinforcing sheets 44 and 46 are wound around the outer periphery of the first tapered portion 22 and the second tapered portion 24 of the cored bar 20. Therefore, as shown in FIG. 4, the first front reinforcing layer 72 is formed on the tip (one end) 20 a side of the cored bar 20.

At this time, the outer peripheral surface of the first front reinforcing layer 72 is substantially flush with the outer peripheral surface of the third tapered portion 26 of the cored bar 20.
The first to third front reinforcing sheets 42, 44, 46 shown in FIG. 3 have substantially triangular portions 42a, 44a, 46a, respectively. As shown in FIG. 4, these substantially triangular portions 42 a, 44 a, 46 a are wound around the second taper portion 24 of the core metal 20, and the outer peripheral surface of the third taper portion 26 and the first front reinforcing layer 72. An outer diameter adjusting layer (front side outer diameter adjusting region) 72a is formed so as to be substantially flush with the outer peripheral surface. The outer diameter adjusting layer 72a has a length in the axial length direction (width in the axial length direction) that is smaller than the total length L of the shaft 12, for example, about 4% to 6%. For this reason, the presence of anisotropy generated in the circumferential direction of the shaft 12 by the substantially triangular portions 42a, 44a, 46a can be suppressed.

The outer diameter adjusting layer 72a is formed between the inner peripheral surface of the shaft 12 at the outer side of the displacement portion 23 between the first and second taper portions 22 and 24 and the displacement portion 25 between the second and third taper portions 24 and 26. The inner peripheral surface of the shaft 12 at the outer position is continuously made smooth. At this time, the outer peripheral surface of the third taper portion 26 of the cored bar 20 and the outer peripheral surface of the first front reinforcing layer 72 of the shaft 12 are formed substantially flush with each other, so the first and second tapered portions 22 and 24 are formed. The thickness of the first front reinforcing layer 72 of the shaft 12 at the outer position of the intermediate displacement portion 23 is gradually reduced toward the rear end side, so that the displacement portion between the second and third taper portions 24, 26 is obtained. The thickness of the first front reinforcing layer 72 of the shaft 12 at the outer position of 25 is substantially zero. The thinning here does not reduce the thickness of the first to third front reinforcing sheets 42, 44, 46 themselves, but the substantially triangular portions 42 a, 44 a, 46 a of the respective sheets 42, 44, 46. By winding the wire around the second taper portion 24 of the cored bar 20, the same state as that gradually reduced is achieved.
Therefore, the outer diameter adjusting layer 72a can prevent a sudden step on the inner peripheral surface of the shaft 12 to reduce the change in the inner diameter of the shaft 12, and can also cause a rapid intensity change in the direction along the axial direction of the shaft 12. Can be prevented. In other words, the outer diameter adjustment layer 72a has a steep difference in rigidity between the portion of the shaft 12 corresponding to the outer peripheral position of the first tapered portion 22 and the portion corresponding to the outer peripheral position of the third tapered portion 26. It can be changed more slowly than the case where the outer diameter adjusting layer 72a is not present.

As shown in FIG. 3, the first to third rear reinforcing sheets 52, 54, 56 are wound around the fourth tapered portion 28 and the fifth tapered portion 30. The first rear reinforcing sheet 52 is wound around the fourth taper portion 28 and the fifth taper portion 30 of the cored bar 20. The second and third rear reinforcing sheets 54 and 56 are arranged on the outer periphery of the first rear reinforcing sheet 52 with the rear ends of the second and third rear reinforcing sheets 54 and 56 aligned with the rear ends of the first rear reinforcing sheet 52. Wound around. At this time, the second and third rear reinforcing sheets 54 and 56 are wound around the outer periphery of the fourth tapered portion 28 and the fifth tapered portion 30 of the cored bar 20. Therefore, as shown in FIG. 4, a rear reinforcing layer 74 is formed on the outer peripheral surfaces of the fourth tapered portion 28 and the fifth tapered portion 30.
At this time, the outer peripheral surfaces of the first front reinforcing layer 72 and the rear reinforcing layer 74 are substantially flush with the outer peripheral surface of the third tapered portion 26 of the core metal 20.

  The first to third rear reinforcing sheets 52, 54, and 56 shown in FIG. 3 have substantially triangular portions 52a, 54a, and 56a, respectively. As shown in FIG. 4, these substantially triangular portions 52a, 54a, and 56a are wound around the fourth taper portion 28, and the outer peripheral surface of the third taper portion 26 of the cored bar 20, the fourth taper portion 28, and the fifth taper portion. An outer diameter adjusting layer (rear side outer diameter adjusting region) 74a is formed so as to be flush with the outer peripheral surface of the rear reinforcing layer 74 of the shaft 12 wound around the tapered portion 30. The outer diameter adjustment layer 74a has a length in the axial length direction (a width in the axial length direction) that is smaller than the total length L of the shaft 12, for example, about 4% to 6%. For this reason, the presence of anisotropy generated in the circumferential direction of the shaft 12 by the substantially triangular portions 52a, 54a, and 56a can be suppressed.

The outer diameter adjusting layer 74a has an inner peripheral surface of the shaft 12 outside the displacement portion 27 between the third and fourth taper portions 26, 28 and a displacement portion 29 between the fourth and fifth taper portions 28, 30. The inner peripheral surface of the shaft 12 at the outer position is continuously made smooth. At this time, since the outer peripheral surface of the third taper portion 26 of the cored bar 20 and the outer peripheral surface of the rear reinforcing layer 74 of the shaft 12 are formed substantially flush with each other, the displacement portion between the fourth and fifth taper portions 28 and 30 is formed. 29, the thickness of the rear reinforcing layer 74 of the shaft 12 at the outer position of the shaft 12 is gradually reduced toward the distal end, and the shaft 12 outside the displacement portion 27 between the third and fourth taper portions 26, 28 is reduced. The thickness of the rear reinforcing layer 74 is substantially zero. Note that the thickness reduction here does not reduce the thickness of the first to third rear reinforcing sheets 52, 54, and 56 themselves, and the substantially triangular portions 52a, 54a, and 56a of the sheets 52, 54, and 56 are cored. By winding on the fourth taper portion 28 of the gold 20, the same state as that gradually reduced is achieved.
Therefore, the outer diameter adjusting layer 74a can prevent a steep step on the inner peripheral surface of the shaft 12, and can prevent a sudden strength change in the direction along the axial direction of the shaft 12. That is, the outer diameter adjustment layer 74a has a steep difference in rigidity between the portion of the shaft 12 corresponding to the outer peripheral position of the third tapered portion 26 and the portion corresponding to the outer peripheral position of the fifth tapered portion 30. It can be changed more slowly than when it has (when the outer diameter adjusting layer 74a is not present).

The first main body sheet 62 is wound around the outer periphery of the first to third front reinforcing sheets 42, 44, 46 and the first to third rear reinforcing sheets 52, 54, 56. For this reason, as shown in FIG. 3, the first main body sheet 62 is directly wound around the cored bar 20 only in the third tapered portion 26.
At this time, since the fiber direction of the reinforcing fibers of the first main body sheet 62 is inclined with respect to the central axis C (axial length direction) of the cored bar 20, the fiber direction of the reinforcing fibers is set in the axial direction of the cored bar 20. Since winding is more difficult than laminating the prepreg material, the first main body sheet 62 can be directly wound around the third taper portion 26 of the core metal 20 having hardness. The reinforcing fiber meanders on the outer periphery of the third taper portion 26 can be wound more firmly than the first main body sheet 62 on the prepreg sheet (the first front reinforcing layer 72 and the rear reinforcing layer 74). The amount can be reduced.
Thus, the strength of the shaft 12 can be stabilized because the prepreg sheet having reinforcing fibers is wound directly on the outer periphery of the third taper portion 26 of the core metal 20 in the direction inclined with respect to the axial length direction. it can. The same applies to a case where a prepreg sheet having reinforcing fibers is wound in a circumferential direction orthogonal to the axial length direction as a direction inclined with respect to the axial length direction.

  The outer peripheral surface of the third tapered portion 26 and the outer peripheral surface of the first front reinforcing layer 72 and the outer peripheral surface of the third tapered portion 26 and the outer peripheral surface of the rear reinforcing layer 74 are substantially flush. Therefore, they have substantially the same taper angle. Since the first main body sheet 62 having a constant thickness is wound around the outer periphery, the outer peripheral surface of the first main body sheet 62 also has substantially the same taper angle as the outer peripheral surface of the shaft 12. At this time, there is no step between the outer peripheral surface of the third tapered portion 26 and the outer peripheral surface of the first front reinforcing layer 72 and between the outer peripheral surface of the third tapered portion 26 and the outer peripheral surface of the rear reinforcing layer 74. Therefore, when winding the 1st main body sheet | seat 62, it can wind easily (lamination | stack).

Then, the second main body sheet 64 having a constant thickness is wound around the outer periphery of the first main body sheet 62, and the first main body sheet 62 and the second main body sheet 64 form the first main body layer 76. For this reason, the outer peripheral surface of the first main body layer 76 has substantially the same taper angle as the outer peripheral surface of the shaft 12.
Further, since the fiber directions of the reinforcing fibers of the first main body sheet 62 and the second main body sheet 64 are shifted, for example, by substantially equal angles in opposite directions with respect to the axial length direction, the torsional rigidity of the shaft 12 is exhibited well. be able to.

A second main body layer 78 is formed by winding a third main body sheet 66 having a constant thickness around the outer periphery of the first main body layer 76. The outer peripheral surface of the second main body layer 78 forms the outer peripheral surface of the shaft 12 and has a constant taper angle with respect to the central axis C of the cored bar 20.
At this time, since the fiber direction of the reinforcing fibers of the third main body sheet 66 is the axial length direction, the bending rigidity of the shaft 12 can be satisfactorily exhibited even in the middle region MS.

  The fourth front reinforcing sheet 48 is aligned with the tips of the first to third front reinforcing sheets 42, 44, 46 and the first to third main body sheets 62, 64, 66. In this state, it is wound around the outer periphery of the third main body sheet 66. For this reason, a second front reinforcing layer 80 is formed on the outer periphery of the distal end portion of the second main body layer 78 by the fourth front reinforcing sheet 48.

  Then, in the same manner as in normal molding, from the outside of the second main body layer 78 and the second front reinforcing layer 80, it is clamped and molded by taping, the core bar 20 and the shaft 12 are heat-cured, the core bar 20 is removed, and the taping tape is removed. The golf club shaft 12 can be obtained by removal, polishing, or the like.

As shown in FIG. 4, first to third front reinforcing sheets 42 are disposed at positions corresponding to the outer circumferences of the first tapered portion 22 and the second tapered portion 24 of the cored bar 20 removed from the inside of the shaft 12. A first front reinforcing layer 72 is formed by 44 and 46. Further, a second front reinforcing layer 80 is formed by the fourth front reinforcing sheet 48. That is, the front region FS of the shaft 12 includes not only the third main body sheet 66 of the second main body layer 78 but also the first front reinforcing layer 72 and the second front reinforcing member having the fiber direction of the reinforcing fibers in the axial length direction. As shown in FIG. 5, the layer 80 has a higher resistance to bending than the middle region MS that resists bending with the third main body sheet 66 alone.
Note that the front region FS has higher bending rigidity on the tip 12a side (TIP side) of the shaft 12 than at a position (BUTT side) close to the middle region MS. This is because the taper angle of the first taper portion 22 of the metal core 20 is small, so that the outer diameters of the first to third front reinforcing sheets 42, 44, 46 wound around the outside of the first taper portion 22 are small. In addition to a small increase in flexural rigidity even when it is increased, when the substantially triangular fourth front reinforcing sheet 48 is wound outside the third main body sheet 56, the winding area on the front end 12a side is reduced. This is because it is larger than the winding area on the end 12b side.
Further, the outer diameter is adjusted by the fourth front reinforcing sheet 48. For this reason, even if the golf club 10 is swung in a state where the tips (first front reinforcing layer 72 and second front reinforcing layer 80) 12a of the shaft 12 are inserted and fixed in the hosel 14a of the head 14, The shaft 12 can be maintained in a good state.

  A rear reinforcing layer 74 is formed by first to third rear reinforcing sheets 52, 54, 56 at positions corresponding to the outer circumferences of the fourth tapered portion 28 and the fifth tapered portion 30 of the cored bar 20. That is, the rear region BS of the shaft 12 is not only the third main body sheet 66 of the second main body layer 78 but also the rear reinforcing layer 74 having the fiber direction of the reinforcing fibers in the axial length direction, as shown in FIG. Bending resistance is strengthened more than the middle region MS that opposes bending rigidity with only the three main body sheet 66.

The rear reinforcing layer 74 has a higher bending rigidity on the rear end 12b side (BUTT side) of the shaft 12 than on a position (TIP side) close to the middle region MS. This is because the bending rigidity is increased by increasing the outer diameters of the first to third rear reinforcing sheets 52, 54, and 56 wound around the fifth tapered portion 30 of the core metal 20. Appears.
Similarly, the middle region MS has higher bending rigidity on the rear end 12b side of the shaft 12 than on the front end 12a side. This shows the effect that the bending rigidity is increased by increasing the outer diameter of the third main body sheet 66 wound around the third tapered portion 26 of the cored bar 20.

As described above, in the present embodiment, the third main body sheet 66 is used in common for the front region FS, the rear region BS, and the middle region MS that specify the bending rigidity of the shaft 12, and in the front region FS, the third body sheet 66 is used. In addition to the third main body sheet 66, the first to fourth front reinforcing sheets 42, 44, 46, and 48 are added to the third main body sheet 66 in the rear region BS, and to the first to third rear reinforcing sheets 52, 54, and 56. Is used. For this reason, the front region FS and the rear region BS have higher bending rigidity than the middle region MS.
Therefore, the rigidity on the grip 16 side is formed higher by the rear region BS (rear reinforcing layer 74) than the portion adjacent to the tip side (the middle region MS). Therefore, when the golf club 10 is swung, the grip 16 side is more rigid than the middle region MS, so that the golf club 10 can be easily controlled and adjacent to the front end side of the rear region BS. Since the middle area MS to be bent can be bent as compared with the grip 16 side, the hitting ball can be easily raised.
Further, the rigidity on the head 14 side is formed higher by the front region FS (front reinforcing layer 72) than the portion adjacent to the rear end side (the middle region MS). For this reason, when the golf club 10 is swung, the head 14 side of the golf club 10 is more rigid than the middle region MS, so that the orientation of the head 14 of the golf club 10 can be stabilized and the hit ball can be easily controlled. can do.

Table 4 shows the first to third front reinforcing sheets 42, 44, and 46 and the first to third rear reinforcing sheets 52, 54, which are used for the shaft 12 for each of the iron numbers from the third iron to the ninth iron. 56 combinations are shown.

As shown in Table 4, for example, in the case of a No. 3 iron, the first to third front reinforcing sheets 42, 44, and 46 have the same basis weight and sheet thickness among F1 to F3 shown in Table 2. F1 having the lowest fiber elastic modulus is used. For the first to third rear reinforcing sheets 52, 54, and 56, B1 having a basis weight and a sheet thickness of B1 to B5 shown in Table 3 is used.
For example, in the case of a 4 iron, the first front reinforcing sheet 42 is F2 among F1 to F3 shown in Table 2, and the second and third front reinforcing sheets 44 and 46 are from F1 shown in Table 2. Of F3, F1 is used. That is, one of the first to third front reinforcing sheets 42, 44, and 46 is changed to change the bending rigidity of the front region FS between the third iron and the fourth iron.
On the other hand, B2 of B1 to B5 shown in Table 3 is used for the first and second rear reinforcing sheets 52 and 54, and B1 of B1 to B5 shown in Table 3 is used for the third rear reinforcing sheet 56. . That is, two of the first to third rear reinforcing sheets 52, 54, and 56 are changed to change the bending rigidity of the rear region BS between the third iron and the fourth iron.

  Then, the front reinforcing sheets 42, 44, and 46 are sequentially changed one by one as the count goes up, and the rear reinforcing sheets 52, 54, and 56 are changed two by two in order, whereby the core bar 20 having the same size and the same shape is changed. Can be used to make the shaft 12 of each count. In the present embodiment, since the cored bar 20 having the same size and the same shape from the 3rd iron to the 9th iron is used, variations in manufacturing accuracy can be suppressed.

  And, as shown in Table 4, in the rear count adjacent to the front count, one of the first to third front reinforcing prepreg sheets 42, 44, 46 is changed, one of which is a fiber The elastic modulus is increased. Further, in the rear count adjacent to the front count, two of the first to third rear reinforcing prepreg sheets 52, 54, 56 are changed to increase the basis weight of the two sheets, The thickness is increased. That is, the front area FS of the shaft 12 has a larger fiber elastic modulus as it is closer to the inner side, and the rear area BS has a smaller basis weight as it is closer to the outer side. For this reason, in the front area FS, a difference in bending rigidity is given by the fiber elastic modulus, and in the rear area BS, a difference is given in weight in addition to the bending rigidity by the basis weight and the sheet thickness. In addition, the front region FS and the rear region BS of the shaft 12 use at least one identical prepreg sheet (having the same number of layers, axial length, and material) between adjacent counts. For this reason, the difference in feeling when the golfer swings can be set as appropriate between adjacent counts (the difference can be increased or decreased depending on the prepreg sheet to be selected), and different characteristics can be set between adjacent counts.

  In the present embodiment, characteristics as shown in FIG. 5 are obtained from the shaft for the 3 iron to the shaft for the 9 iron. The horizontal axis in FIG. 5 indicates the position from the tip 12a of the shaft 12, and the vertical axis indicates the bending rigidity (EI) of the shaft 12.

The bending rigidity of the front region FS and the rear region BS is the same or higher as the golf club 10 has a larger count. By using the prepreg sheet shown in Table 4, the shaft 12 according to the present embodiment can soften the front region FS and the rear region BS with an appropriate rigidity difference as the number is lower (the number is smaller) as shown in FIG. The shafts 12 in the front region FS and the rear region BS can be hardened with an appropriate rigidity difference as the count is higher (the count is larger). Bending stiffness of the front region FS is about the range, for example, from 16N · ^{m 2} of 60N · ^{m 2,} the bending stiffness of the rear region BS is approximately ranging from, for example 28N · ^{m 2} of 160 N · ^{m 2.} In the front region FS at a position of 100 mm from the tip 12a of the shaft 12 in FIG. 5, there is a difference of about 2N · m ² to 3N · m ² with respect to the adjacent count. Further, in the rear area BS in position 800mm from the front end 12a of the shaft 12 in FIG. 5, there is a difference of about ranging from relative to adjacent count e.g. 6N · ^{m 2} of 8N · ^{m 2.}
The rear region BS has a larger amount of increase in flexural rigidity (increase rate) than the front region FS. Further, as shown in FIG. 5, the bending rigidity is relatively higher on the rear end 12b side (rear region BS) than on the front end 12a side (front region FS) of the shaft 12. For this reason, when the golf club 10 is swung, the golf club 10 having high bending rigidity can be reliably controlled on the grip 16 side (rear end side), and the front portion (front end side) is on the grip 16 side (hand side). Since it bends more, a hitting ball can be made easy to go up.

On the other hand, the middle region MS of the shaft 12 uses the first to third main body sheets 62, 64, 66 having the same composition from the 3rd iron to the 9th iron. For this reason, the bending rigidity (ease of bending) and the axial length of the middle region MS are not different for each count. However, although the bending rigidity of the middle region MS depends on manufacturing accuracy, for example, an error of about ± 0.5 N · m ² can be sufficiently allowed.
As described above, since the middle region MS of the shaft 12 is shared by the respective iron numbers, the bending (softness) in the middle region MS when the golf club 10 is swung can be made the same. Therefore, the feel (for example, flexibility and softness) given to the golfer by the middle region MS during the swing can be made substantially the same.
Since the middle region MS is formed between the front region FS and the rear region BS by winding the prepreg around the outer periphery of the front region FS and the rear region BS, the bending rigidity of the middle region MS is set to the front portion. It can be made lower than the region FS and the rear region BS, and the middle region MS of the shaft 12 can be most easily bent during the swing, and the front region FS and the rear region BS can be made more difficult to bend than the middle region MS. Further, by making the middle region MS of the shaft 12 the region having the lowest bending rigidity of the shaft 12, the middle region MS and the rear region BS can be more reliably between the front region FS and the middle region MS. It is possible to easily recognize the difference in bending stiffness between the two.

Each shaft 12 has a lower bending rigidity value in the front region FS, the middle region MS, and the rear region BS as the number is lower (for example, the third iron), and the bending rigidity value is higher as the number is higher (for example, the ninth iron). The difference is big. For this reason, the higher the number of the bending rigidity value, the higher the number of the shaft 12 should be harder at the time of swinging. However, the bending rigidity value of the middle region MS (about 25% to about 50% of the total length of the shaft 12) Since it is substantially the same regardless of the count, the higher the count, the easier it is to feel the bending (softness) of the middle region MS of the shaft 12 during the swing.
On the other hand, the shaft 12 should be softer at the lower count at the time of swing, but the bending rigidity difference becomes smaller as the shift from the higher count to the lower count is performed. Can be difficult to feel. For this reason, it is easier to feel the softness of the middle region MS during the swing as the higher count, and the softness of the middle region MS is less likely to be felt during the swing as the lower count, so At the swing timing, the low count shaft 12 can be brought close to the high count swing timing. Therefore, according to the present embodiment, it is possible to provide a golf club set (shaft set) that is easy to swing at the same timing. That is, the characteristics of the shaft 12 can be set based on a certain flow.
Since the middle region MS has a smaller bending rigidity value than the other regions (the front region FS and the rear region BS), the bending of the shaft 12 is most easily felt in the middle region MS, and the swing timing is easily adjusted.

  Accordingly, the higher the numbered shaft 12, the harder the shaft 12 is to bend, and the direction of the head 14 can be stabilized at the time of hitting the ball, but the swing can be performed with the low numbered shaft 12 approaching the feeling of swinging. . Further, the lower the count, the softer the shaft 12, the face 14b of the head 14 can easily face upward, the launch angle can be increased, and the hitting ball can be lifted easily. Swing can be performed in the state.

In this embodiment, it is preferable that the length L of each shaft 12 is adjusted by cutting the rear region BS. Therefore, by adjusting the weight on the rear end side instead of on the front end side of the shaft 12, the flow of the center of gravity can be easily set for each count.
Of course, the length L of the shaft 12 may be adjusted by cutting both the front region FS and the rear region BS, or only the front region FS. However, the length adjustment is the same for each count (for example, if the rear area BS is cut with a 3 iron, the rear area BS is similarly cut with a 4 to 9 iron) It is preferable from the viewpoint of aligning the characteristics (flow) of the shaft 12.

As described above, according to the present embodiment, it is easy to raise the hit ball during the swing of the golf club 10 by using the shaft 12 having the middle region MS whose bending rigidity is lower than that of the front region FS and the rear region BS. The golf club 10 in which the orientation of the head 14 is stabilized can be provided.
The shaft 12 according to the present embodiment has the middle region MS having the same bending rigidity from the 3rd iron to the 9th iron, and the front region FS in the front and the rear region BS in the rear thereof are both softer as the number is smaller. doing. For this reason, the smaller the count, the easier the face 14b of the head 14 faces upward, the launch angle can be increased, and the hit ball can be raised easily. On the other hand, the larger the number, the harder it is and the direction of the face 14b of the head 14 can be stabilized at the time of hitting, so that the direction of the hitting ball can be made more stable.
Further, since the bending rigidity of the middle region MS is made common regardless of the count, when the golf club 10 is swung, the feeling transmitted from the middle region MS to the golfer's hand can always be in the same state.

In addition, if the difference in the fiber elastic modulus used for the prepreg sheets 42, 44, and 46 used in the front region FS of the shaft 12 is increased between adjacent counts, the shaft 12 having greatly different characteristics can be obtained, and the fiber elastic modulus If the difference is reduced between adjacent counts, the characteristics can be made closer between adjacent counts.
Similarly, if the basis weight used for the prepreg sheets 52, 54, and 56 used for the rear region BS and the difference in sheet thickness are increased between adjacent counts, a shaft 12 having greatly different characteristics can be obtained, and the basis weight, If the difference in sheet thickness is reduced between adjacent counts, the characteristics can be made closer between adjacent counts.

  Next, a second embodiment will be described with reference to FIG. This embodiment is a modification of the first embodiment, and the same members as those described in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The shaft 12 of each of the count golf clubs 10 described in the first embodiment has three reinforcing prepregs in both the front region FS and the rear region BS, whereas in the present embodiment shown in FIG. The shaft 12 of each count golf club 10 has one reinforcing prepreg for both the front region FS and the rear region BS.

  For example, as the reinforcing prepreg sheet 42 in the front region FS, a material having a higher fiber elastic modulus is used for the 4th iron than for the 3rd iron. At this time, the basis weight and the sheet thickness are preferably substantially the same. This relationship is the same for 4 irons, 5 irons, 5 irons and 6 irons,..., 8 irons and 9 irons. For this reason, the bending rigidity of the front region FS of the shaft 12 increases as the count increases. Since the basis weight and the sheet thickness are substantially the same for each count, the weight change of the front region FS can be kept low.

  For example, as the reinforcing prepreg sheet 52 in the rear region BS, a sheet having a larger basis weight and a larger sheet thickness is used for the fourth iron than for the third iron. At this time, it is preferable that the fiber elastic modulus is substantially the same. This relationship is the same for 4 irons, 5 irons, 5 irons and 6 irons,..., 8 irons and 9 irons. For this reason, the bending rigidity of the rear region BS of the shaft 12 increases as the count increases, and the weight of the rear region BS increases. Therefore, the weight adjustment of the shaft 12 can be performed in the rear region BS.

  In the present embodiment, the front region FS and the rear region BS have been described as an example using one reinforcing prepreg sheet 42, 52 in which the fiber direction is the axial length direction, but the fiber direction is axial in the front region FS. The shaft 12 may be formed by using a plurality of reinforcing prepreg sheets such as three in the long direction and using one reinforcing prepreg sheet whose fiber direction is the axial direction in the rear region BS. Further, a shaft using a single reinforcing prepreg sheet whose fiber direction is the axial length direction in the front region FS and a plurality of reinforcing prepreg sheets such as three whose fiber direction is the axial direction is used in the rear region BS. 12 may be formed. When the shaft 12 is formed by using a plurality of reinforcing prepreg sheets, when one or two of the adjacent prepreg sheets are produced, if the number of the prepreg sheets is large, the bending rigidity is high. When the count is small, the one with low bending rigidity is used.

Therefore, the middle region MS has the same bending rigidity regardless of the count, and the bending stiffness is increased as the number is increased in the front region FS and the rear region BS, thereby obtaining a common flexibility in the middle region MS. No. 3, No. 4, No. 4, No. 5, ..., No. 8, No. 9 Iron can be made difficult to bend during swing.
On the other hand, as described in the first embodiment, the middle region MS makes it easier to feel the softness at the time of swing as the higher count, and the softness at the time of the swing is less likely to be felt as the lower count. It is possible to provide a golf club set (shaft set) that is easy to swing at this timing.

  Next, a third embodiment will be described with reference to FIG. This embodiment is a modification of the first and second embodiments.

The cored bar 120 shown in FIG. 7 differs from the cored bar 20 of the first and second embodiments in the length of the intermediate region MM and the rear region BM.
In the first embodiment shown in FIG. 3, the length of the front region FS of the shaft 12 is about 25% of the total length of the core metal 20, and the length of the middle region MS is about 25% of the total length of the core metal 20, It has been described that the length ratio of the rear region BM (the fourth taper portion 28 and the fifth taper portion 30) is approximately 50%.
On the other hand, as shown in FIG. 7, the cored bar 120 of the present embodiment has a length ratio of the intermediate region MM (third tapered portion 126) of about 35%, and a rear region BM (fourth tapered portion). This is an example in which the length ratio of 128 and the fifth taper portion 130) is about 40%. For this reason, the shaft 12 manufactured using the core metal 120 also has a length ratio of the front area FS of about 25%, a length ratio of the rear area BS of about 40%, and the length of the middle area MS. The ratio is about 35%. That is, when the front end 12a of the shaft 12 is 0% and the rear end 12b is 100%, the front region FS is a position from 0% to about 25%, and the middle region MS is a position from about 25% to about 60%. In addition, the rear region BS is at a position of approximately 60% to 100%.

Therefore, when the shaft 12 is manufactured using the core bar 120 according to the present embodiment, the middle region MS becomes longer in accordance with the length ratio of the intermediate region MM of the core bar 120, and the rear region BS is behind the core bar 120. It becomes shorter according to the length ratio of the region BM. Also in this case, the bending rigidity common to the middle region MS is obtained by increasing the bending rigidity as the number of the front region FS and the rear region BS is increased in the middle region MS of the shaft 12 regardless of the number. It is possible to make the 4th iron from the 3rd, the 5th iron from the 4th,...
On the other hand, as described in the first embodiment, the front end 12a side (head 14 side) and the rear end of the shaft 12 are provided by the middle region MS provided in the range of about 25% to about 60% from the front end 12a side of the shaft 12. The bending rigidity on the 12b side (grip 16 side) can be maintained in a state in which a tendency similar to the state shown in FIG. 5 is obtained. For this reason, the front region FS and the rear region BS having higher bending stiffness than the middle region MS can be produced in the same manner as described in the first embodiment while producing the middle region MS having low bending stiffness. Therefore, while obtaining a sense of bending in the middle region MS, it is easier to feel the softness during the swing as the higher count, and the softness during the swing is less likely to be felt as the lower count. Therefore, it is possible to provide a golf club set (shaft set) that is easy to swing at the same timing.

  Although several embodiments have been specifically described so far with reference to the drawings, the present invention is not limited to the above-described embodiments, and all the embodiments performed without departing from the scope of the invention are not limited thereto. Including.

  DESCRIPTION OF SYMBOLS 10 ... Golf club, 12 ... Shaft, 12a ... Tip, 12b ... Rear end, FS ... Front region, BS ... Rear region, MS ... Middle region, 14 ... Head, 14a ... Hosel, 14b ... Face, 16 ... Grip, 20 ... core metal, 20a ... tip, 20b ... rear end, 22, 24, 26, 28, 30 ... taper part, 23, 25, 27, 29, 31 ... displacement part, 32 ... straight part, FM ... front region, BM ... rear region, MM ... middle region, 42 ... first front reinforcing sheet, 44 ... second front reinforcing sheet, 46 ... third front reinforcing sheet, 42a, 44a, 46a ... substantially triangular portion, 48 ... Fourth front reinforcing sheet, 52 ... first rear reinforcing sheet, 54 ... second rear reinforcing sheet, 56 ... third rear reinforcing sheet, 52a, 54a, 56a ... substantially triangular portion, 62 ... first body prepreg sheet, 64 ... No. Main body prepreg sheet, 66 ... third main body prepreg sheet, 72 ... first front reinforcing layer, 72a ... outer diameter adjusting layer, 74 ... rear reinforcing layer, 74a ... outer diameter adjusting layer, 76 ... main body layer, 78 ... main body Layer, 80 ... second front reinforcement layer.

Claims (6)

A tapered cored bar having a front region of an axial front portion, a rear region of an axial rear portion, and an intermediate region connected to each other by a taper-shaped step tapered toward the axial front portion. A shaft set for a golf club that is formed by winding a prepreg impregnated with a synthetic resin into a reinforcing fiber and has a shaft for each golf club count that has a length that decreases as the count of the golf club increases.
Each count shaft is
A prepreg including a shape portion that forms a front-side outer diameter adjusting layer that eliminates the step on the front region side of the core metal and is flush with the outer peripheral surface of the intermediate region from the outer peripheral surface of the front region. A front region formed by winding around a front region;
A prepreg including a shape portion that forms a rear-side outer diameter adjusting layer that eliminates the step on the rear region side of the core bar and makes the outer peripheral surface of the rear region flush with the outer peripheral surface of the middle region. A rear region formed by winding around a rear region;
A middle region that is formed between the front region and the rear region by winding a prepreg along the outer region of the front region and the rear region along the intermediate region of the core metal ,
Comprising
The bending stiffness of the front region and the rear region is set to be equal to or higher than the previous count as the golf club count increases, and the bending stiffness of the middle region is set to be the same for each count, and The shaft set characterized by relieving a change in bending rigidity generated at the step by the flush outer peripheral surface.   2. The shaft set according to claim 1, wherein the weight of the rear region is the same as or larger than that of the front count as the count of the golf club increases.   3. The front region and the rear region are formed by winding a plurality of prepregs, and at least one identical prepreg is used in adjacent counts. The shaft set described in 1.   At least one of the front region and the rear region has at least three reinforcing prepregs along the intermediate region of the core metal and separately from the prepreg wound around the outer periphery of the front region and the rear region. The shaft set according to any one of claims 1 to 3, wherein the shaft set is provided. As the prepreg in the front region, one having a fiber elastic modulus of 240 GPa to 400 GPa is used. The fiber elastic modulus increases as the count increases, and the difference in fiber elastic modulus between adjacent counts is in the range of 50 GPa to 110 GPa. Things are used,
As the prepreg in the rear region, those having a basis weight of 100 g / m ² to 250 g / m ² are used. The basis weight increases as the count increases, and the difference in basis weight between adjacent counts starts from 10 g / m ^2. The shaft set according to any one of claims 1 to 4, wherein a shaft in a range of 60 g / m ² is used.   An iron set in which a head and a grip are attached to each shaft of the shaft set according to any one of claims 1 to 5.

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