JP2012010799A - Shaft for golf club - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shaft for a golf club that prevents a step from being generated on the inner circumferential face of the shaft and a taper from being changed on the inner circumferential side even if a reinforcement layer is formed in the inmost layer of the shaft, exhibits a desired reinforcement effect without significantly changing thickness of the reinforcement layer, and prevents anisotropy.SOLUTION: The shaft 12 for a golf club is formed by winding a fiber reinforced prepreg on a tapering core metal 20 in which an intermediate tapered part 28 gently inclined to a front tapered part 26 and a rear tapered part 30 is continuously arranged between them having a common central axis C on the axial front side. The reinforcement layer 74 is formed by winding a reinforcement prepreg 48 from the intermediate tapered part 28 to the rear tapered part of the core metal. An outside diameter adjusting region 74a is formed in the front part of the reinforcement layer positioned in the intermediate tapered part so that the taper of the outer circumferential face of the reinforcement layer is substantially the same as that of the front tapered part. A body layer 76 is wound around the outside of the front tapered part and the reinforcement layer.

Description

  The present invention relates to a golf club shaft formed of a fiber reinforced composite material.

  For example, the golf club shaft disclosed in Patent Document 1 discloses a tapered shaft whose outer diameter increases from the front end (head side) toward the rear end (grip side). The inner diameter from the rear end (grip side) of this shaft to 500 mm is constant, and a reinforcing layer is formed on the whole or part of the innermost layer at that position (range of 500 mm from the rear end of the shaft). At this time, the reinforcing layer forming portion of the mandrel around which the prepreg sheet is wound when producing the shaft is a straight that becomes relatively thin with respect to the taper shape by about the thickness of the reinforcing layer. When a prepreg sheet that forms a reinforcing layer is wound around the reinforcing layer forming portion of the mandrel, the prepreg sheet is wound in a state in which there is little taper change, so that it is difficult to generate a step on the outer peripheral surface of the shaft. The occurrence of winding defects is suppressed.

JP 2001-46566 A

In the technique disclosed in Patent Document 1, a reinforcing layer can be formed between the outer peripheral surface that gradually increases in diameter by the amount that the reinforcing layer forming portion of the mandrel does not increase in diameter and becomes thin as a straight. However, a step corresponding to the thickness of the reinforcing layer is generated at the end of the reinforcing layer, and winding failure is likely to occur. In addition, since the thickness of the reinforcing layer between the outer layer where the inner diameter gradually increases and the straight mandrel has changed, the reinforcing effect differs between the front and rear ends of the reinforcing layer, and the rigidity adjustment is complicated. It becomes.
In addition, when forming a reinforcing layer by the sheet winding method, a triangular sheet is wound from at least 0 ply to several plies from the leading end side to the trailing end side of the sheet forming the reinforcing layer. The winding number is different and anisotropy occurs in the circumferential direction. Therefore, when swinging the golf club, it may be difficult to perform a stable swing.

  The present invention has been made to solve such a problem, and even if the reinforcing layer is formed in the innermost layer of the shaft, the step generated inside the sheet wound around the outer side and the taper change can be reduced. Another object of the present invention is to provide a golf club shaft that can produce a desired reinforcing effect without greatly changing the thickness of the reinforcing layer, can hardly generate anisotropy as much as possible, and has good directivity. And

In order to solve the above-mentioned problem, according to the present invention, between the front taper portion on the axial front side having a common central axis and the rear taper portion on the rear side in the axial direction with respect to the front taper portion, these A shaft for a golf club formed by winding a fiber reinforced prepreg in which a reinforcing fiber is impregnated with a synthetic resin is wound around a tapered core bar in which an intermediate taper portion having a gentle slope with respect to the taper portion is continuously arranged. A reinforcing prepreg is wound from the intermediate taper portion to the rear taper portion of the metal core to form a reinforcing layer, and an outer diameter adjusting portion is formed at the front portion of the reinforcing layer located at the intermediate taper portion, thereby reinforcing the reinforcement. The taper of the outer peripheral surface of the layer is substantially the same as the taper of the front taper portion, and the main body layer is wound around the front taper portion and the reinforcing layer.
Moreover, it is preferable that the taper angle of the front taper portion and the taper angle of the rear taper portion are substantially the same.
The intermediate taper portion is preferably located 50% to 70% from the rear end of the entire shaft length L and has a width of 6% to 10% of the reinforcing layer.
Moreover, it is preferable that the fiber direction of the reinforcing fiber of the innermost body layer of the main body layer is inclined with respect to the axial length direction of the shaft.

According to this invention, since the taper angle of the outer peripheral surface of the reinforcing layer can be made substantially the same as the taper angle of the front taper portion of the core metal, when the main body layer is wound around these, It is possible to prevent a step from being formed on the outer periphery. Further, the inner circumference of the shaft is formed by forming the outer diameter adjustment portion of the reinforcing layer at the outer circumference position of the intermediate taper portion of the core bar, so that the inner circumference surface of the shaft corresponding to the outer circumference of the intermediate taper portion becomes the intermediate taper portion. It can approach the outer peripheral surface of an adjacent front taper part. And since the main body layer can be wound directly on the outside of the front taper portion of the core metal, when arranging the fiber direction of the reinforcing fiber in the axial length direction, of course, the reinforcing fiber in the direction deviating from the axial length direction. Even when the fiber direction is arranged, the meandering of the reinforcing fibers can be suppressed.
By making the taper angle of the front taper portion substantially the same as the taper angle of the rear taper portion, the thickness of the reinforcing layer outside the rear taper portion can be made substantially constant. And the outer diameter taper of the part which laminated | stacked the reinforcement layer becomes substantially the same as the taper of a metal core, and since there is no level | step difference in laminating | stacking a main body layer, a main body layer can be laminated | stacked easily.
By setting the intermediate taper portion to the front side (head side) of the shaft length direction center of the shaft, the rigidity on the grip side can be increased, the head side can be bent more easily than the grip side, and the hitting ball can be raised easily. . Further, since the intermediate taper portion has only an axial width of about 6% to 10% of the reinforcing layer, the occurrence of anisotropy with respect to the shaft can be suppressed.
By inclining the fiber direction of the reinforcing fibers in the innermost layer of the main body layer with respect to the axial direction, the torsional rigidity can be enhanced. Also, generally, when laminating a prepreg material having a fiber direction of reinforcing fibers in a direction inclined with respect to the axial direction of the core metal, winding is performed rather than laminating a prepreg material having a fiber direction of reinforcing fibers in the axial direction. Although it is difficult, even when the prepreg material having the fiber direction of the reinforcing fiber in the direction inclined with respect to the axial direction of the core metal is laminated by directly winding the innermost layer of the main body layer around the core metal Can be wound. Further, as described above, since the prepreg is wound directly around the core metal, meandering of the reinforcing fiber can be suppressed.

Schematic which shows the golf club which concerns on 1st and 2nd embodiment. Schematic which shows the shaft for golf clubs concerning 1st and 2nd 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. 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. The schematic sectional drawing of the state which wound the prepreg sheet | seat around the metal core when manufacturing the shaft for golf clubs concerning 2nd Embodiment.

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.

  As shown in FIG. 1, a golf club 10 includes a hollow shaft (tubular body made of a fiber-reinforced composite material) 12 made of a laminate of fiber-reinforced prepreg sheets, and a tip (one end) 12a of the shaft 12 (see FIG. 2). The head 14 is attached to the narrow-diameter portion, and the grip 16 made of, for example, rubber or leather is attached to the large-diameter portion of the rear end (the other end) 12b (see FIG. 2) of the shaft 12. 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.

  The golf club shaft 12 is used, for example, for an iron shaft having an overall length L of about 850 mm to 1100 mm. The outer diameter of the front end 12a of the shaft 12 is about 4.0 mm to 6.0 mm, and the outer diameter of the rear end 12b of the shaft 12 is about 14.5 mm to 16.5 mm. The outer peripheral surface of the shaft 12 has an inclination (taper angle) of about 6/1000 to 10/1000 with respect to the central axis C, and is particularly tapered so as to have an inclination of 8/1000. preferable. That is, this is an outer diameter at which the golfer can easily grip the grip due to the relationship of the grip diameter with respect to the tip diameter of the shaft 12 and can easily exert the grip force.

As shown in FIG. 3, a mandrel 20 for producing the shaft 12 according to this embodiment has a first taper portion 22 and a second taper in order from the front end 20a to the rear end 20b. A portion 24, a third taper portion (front taper portion) 26, a fourth taper portion (intermediate taper portion) 28, a fifth taper portion (rear taper portion) 30, and a straight portion 32.
That is, between the first taper portion 22 and the second taper portion 24, between the second taper portion 24 and the third taper portion 26, between the third taper portion 26 and the fourth taper portion 28, and the fourth taper. Between the portion 28 and the fifth taper portion 30, and between the fifth taper portion 30 and the straight portion 32, a circumferential displacement portion serving as a boundary for changing the inclination of the outer peripheral surface of the cored bar 20, respectively. 23, 25, 27, 29, and 31 are formed.

Table 1 below shows the inclination (taper angle) of each tapered portion with respect to the central axis C of the core metal 20 and each tapered portion (adjacent displacement portions 23, 25, 27, 29, 31) with respect to the total length L of the shaft 12. (Between length). For example, the first tapered portion 22 has an inclination of about 8.5 / 1000 to 9.5 / 1000 with respect to the central axis C, and has a length of 16% to 25% with respect to the total length L of the shaft 12. Have. The first taper portion 22 preferably has an inclination of about 8.9 / 1000 with respect to the central axis C, and the first taper portion 22 is within 20% of the total length L of the shaft 12 from the tip 12a. Although it is particularly preferable to have a length, this is appropriately set according to the length of the hosel 14a of the head 14.

The second taper portion 24 is approximately four times larger in inclination than the first taper portion 22. The fourth taper portion (intermediate taper portion) 28 is a taper that is short and loose (small in inclination) with respect to the fifth taper portion (rear 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 (front 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.
For example, when the fifth taper portion 30 is located at 50% of the total length of the shaft 12, the total length of the first taper portion 22 and the third taper portion 26 is 32 with respect to the total length of the shaft 12. % To 42% is preferable. For example, the length of the first and second front reinforcing layers 72 and 80 described later formed on the outer periphery of the first tapered portion 22 of the core metal 20 is set to the length of the hosel 14a of the head 14. Or the length of only the first and second main body layers 76 and 78, which will be described later, formed on the outer periphery of the third taper portion 26 of the core metal 20 is adjusted to bend when the golf club 10 swings. This is to appropriately set the desired range.

The shaft 12 is a fiber-reinforced prepreg sheet in which a reinforcing fiber is impregnated with a synthetic resin, and includes first to third front reinforcing sheets 42, 44, 46, a rear reinforcing sheet 48, and first to third main bodies. It is formed by winding the sheets 50, 52, 54 and the fourth front reinforcing sheet 56 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 2 below shows the fiber direction of the reinforcing fibers and the thickness of the prepreg sheet with respect to the core 20 of each prepreg sheet constituting the shaft 12.

As shown in Table 2, for example, the first to third front reinforcing sheets 42, 44, and 46 each have a fiber direction in the axial direction of the core bar 20, and have a thickness of 0.10 mm to 0.30 mm. Degree. That is, the first to third front reinforcing sheets 42, 44, 46 form an axial length direction fiber layer in which the fiber direction is arranged in the axial length direction of the cored bar 20, and are used for adjusting the bending rigidity. The first to third front reinforcing sheets 42, 44, 46 have a resin amount (fiber content) of 20 to 40 wt% and a tensile elastic modulus of 10 to 400 GPa.
Similarly to the first to third front reinforcing sheets 42, 44, 46, the fourth front reinforcing sheet 56 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 is bent. Used for stiffness adjustment. The fourth front reinforcing sheet 56 has a resin amount (fiber content) of 20 to 40 wt% and a tensile elastic modulus of 10 to 400 GPa.

  The rear reinforcing sheet 48 is formed so that a knitted sheet (here, when the sheet is formed into a cylindrical shape, the axial length direction and all directions in the inclination direction (including the circumferential direction) with respect to the axial length direction can be reinforced with one sheet. It is preferable to use various sheets or prepreg sheets having fiber directions in the axial direction and the circumferential direction, respectively. It is also preferable to use a prepreg sheet or the like in which reinforcing fibers are knitted in a direction of ± 45 degrees, for example. In this case, the rigidity is adjusted by winding about 0.95 to 1 ply around the metal core 20 on the rear side of the substantially triangular portion 48a of the thick sheet (rear reinforcing sheet 48) of 0.15 mm or more. It is easy to perform and can reduce anisotropy.

The first and second main body sheets 50 and 52 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 50, the reinforcing fibers are inclined with respect to the axial length direction, for example, + (plus) 30 degrees to 50 degrees (particularly preferably +45 degrees), and the second main body sheet 52 has the reinforcing fibers in the axial length direction. For example, the inclination is − (minus) 30 to 50 degrees (particularly preferably −45 degrees). The first and second main body sheets 50 and 52 have a resin amount (fiber content) of 20 to 40 wt% and a tensile elastic modulus of 10 to 400 GPa.
The 3rd main body sheet | seat 54 forms the axial direction direction fiber layer which distributes a fiber direction in the axial direction of the metal core 20, and is used for adjustment of bending rigidity. The third main body sheet 54 has a resin amount (fiber content) of 20 to 40 wt% and a tensile elastic modulus of 10 to 400 GPa.
The first to third front reinforcing sheets 42, 44, 46, the rear reinforcing sheet 48, the first to third main body sheets 50, 52, 54, and the fourth front reinforcing sheet 56 are each constant thickness. Is used.

  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. For this reason, the 1st front part reinforcement layer 72 is formed in the front-end | tip (one end) 20a side of the metal core 20. As shown in FIG.

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 taper portion (front taper portion) 26 of the core metal 20.
The first front reinforcing sheet 42 shown in FIG. 3 has a substantially triangular portion 42a, and the second and third front reinforcing sheets 44 and 46 have substantially rectangular portions 44a and 46a. The substantially triangular portion 42a and the substantially rectangular portions 44a and 46a are wound around the second taper portion 24 of the metal core 20, and the outer peripheral surface of the third taper portion (front taper portion) 26 and the first front reinforcing layer. An outer diameter adjusting layer (outer diameter adjusting portion) 72a that is substantially flush with the outer peripheral surface of 72 is formed.
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 tapered portion (front tapered 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. The thickness of the first front reinforcing layer 72 of the shaft 12 at the outer position of the displacement portion 23 between the two taper portions 22 and 24 is gradually reduced toward the rear end side, so that the second and third taper portions 24 are formed. , 26, the thickness of the first front reinforcing layer 72 of the shaft 12 at the outer position of the displacement portion 25 is substantially zero. The thinning here does not reduce the thickness of the first to third front reinforcing sheets 42, 44, 46 itself, but the substantially triangular portion 42 a, the substantially rectangular portion of each sheet 42, 44, 46. By winding 44a and 46a around the second taper portion 24 of the core bar 20, the same state as that gradually reduced is achieved.
Therefore, the outer diameter adjusting layer 72a can prevent a steep step from occurring on the inner peripheral side of the shaft 12, and can prevent a sudden intensity change in the direction along the axial direction of the shaft 12. In other words, the outer diameter adjusting layer 72 a has a rigidity between a portion of the shaft 12 corresponding to the outer peripheral position of the first tapered portion 22 and a portion corresponding to the outer peripheral position of the third tapered portion (front tapered portion) 26. The difference can be changed more slowly than when there is a steep step.

As shown in FIG. 3, the rear reinforcing sheet 48 has a constant thickness and is wound around the fourth taper portion (intermediate taper portion) 28 and the fifth taper portion (rear taper portion) 30. 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 taper portion (front taper portion) 26 of the cored bar 20.

The rear reinforcing sheet 48 shown in FIG. 3 has a substantially triangular portion 48a. The substantially triangular portion 48a is wound around the fourth taper portion (intermediate taper portion) 28, and the outer peripheral surface of the third taper portion (front taper portion) 26 of the core metal 20, the fourth taper portion 28 and the fifth taper portion. An outer diameter adjusting layer (outer diameter adjusting portion) 74 a 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 (rear tapered portion) 30.
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 (front taper portion) 26 of the core metal 20 and the outer peripheral surface of the rear reinforcing layer 74 of the shaft 12 are formed substantially flush, the fourth and fifth taper portions 28 are formed. 30, the thickness of the rear reinforcing layer 74 of the shaft 12 at the outer side of the displacement portion 29 between the third and fourth taper portions 26, 28 is gradually reduced toward the distal end, and the displacement portion 27 between the third and fourth taper portions 26, 28 is reduced. The thickness of the rear reinforcing layer 74 of the shaft 12 on the outside is substantially zero. The thinning here does not reduce the thickness of the rear reinforcing sheet 48 itself, but gradually reduces the thickness by winding the substantially triangular portion 48a of the sheet 48 around the fourth tapered portion 28 of the core metal 20. It will be in the same state as the state.
Therefore, the outer diameter adjusting layer 74a can prevent a steep step on the inner peripheral side 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 74 a is a portion of the shaft 12 corresponding to the outer peripheral position of the third tapered portion (front tapered portion) 26 and a portion corresponding to the outer peripheral position of the fifth tapered portion (rear tapered portion) 30. And the rigidity difference between the two can be changed gradually.

As shown in Table 1, the length of the fourth taper portion (intermediate taper portion) 28, that is, the axial length of the outer diameter adjusting layer 74 a of the rear reinforcing layer 74 is equal to the total length L of the shaft 12. In contrast, the axial width is preferably about 4% to 6% or about 6% to 10% with respect to the rear reinforcing layer 74. The axial length of the outer diameter adjusting layer 74a of the rear reinforcing layer 74 is about 4% to 6% with respect to the total length L of the shaft 12, or more than about 6% to 10% with respect to the rear reinforcing layer 74. When it is large (long), anisotropy is likely to occur in the shaft 12 due to the triangular sheet (substantially triangular part 48a) of the rear reinforcing sheet 48. On the other hand, when the ratio is small (short), it is almost as if a step is formed by the fourth taper portion 28 that is continuous with the third taper portion (front taper portion) 26 and the fifth taper portion (rear taper portion) 30. The same state occurs, and the rigidity difference between positions adjacent to each other in the axial direction of the shaft 12 changes too rapidly.
The same applies to the outer diameter adjusting layer 72a of the first front reinforcing layer 72.

The first main body sheet 50 is wound around the outer periphery of the first to third front reinforcing sheets 42, 44, 46 and the rear reinforcing sheet 48. For this reason, as shown in FIG. 3, the first main body sheet 50 is directly wound around the cored bar 20 only by the third taper portion (front taper portion) 26.
At this time, since the fiber direction of the reinforcing fiber of the first main body sheet 50 is inclined with respect to the central axis C (axial length direction) of the cored bar 20, the fiber direction of the reinforcing fiber 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 50 can be wound directly around the third taper portion 26 of the core metal 20 having hardness. The reinforced fiber meandering around the outer periphery of the third taper portion 26 can be wound more firmly than the first main body sheet 50 on the prepreg sheet (the first front reinforcing layer 72 and the rear reinforcing layer 74). The amount can be reduced. As will be described later, the position corresponding to the outer periphery of the third taper portion 26 is 50% or more in front of the total length L of the shaft 12 (front side from half), and this position has a relatively small diameter and low rigidity. This position is a position that has a great influence on the control of the head 14 and the ease of rising of the hit ball due to bending, but the meandering of the reinforcing fibers at that position can be reduced. Therefore, the shaft 12 can obtain a desired stable strength.
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 50 having a constant thickness is wound around the outer periphery, the outer peripheral surface of the first main body sheet 50 is also substantially the same taper angle as the outer peripheral surface of the shaft 12 (as described above, for example, about 6/1000 To an inclination of about 10/1000). 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 50, it can wind easily (lamination).

Then, the second main body sheet 52 having a constant thickness is wound around the outer periphery of the first main body sheet 50, and the first main body sheet 50 and the second main body sheet 52 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 (as described above, for example, an inclination of about 6/1000 to 10/1000).
In addition, the first main body sheet 50 and the second main body sheet 52 exhibit the torsional rigidity of the shaft 12 satisfactorily because the fiber directions of the reinforcing fibers are shifted, for example, by substantially equal angles in opposite directions with respect to the axial direction. be able to.

A second main body layer 78 is formed by winding a third main body sheet 54 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 is the outer peripheral surface of the shaft 12 and has a constant taper angle with respect to the central axis C of the core metal 20 (as described above, for example, about 6/1000 to 10/1000 or so. Slope).
At this time, since the fiber direction of the reinforcing fibers of the third main body sheet 54 is the axial length direction, the bending rigidity of the shaft 12 can be satisfactorily exhibited.

  The fourth front reinforcing sheet 56 is aligned with the tips of the first to third front reinforcing sheets 42, 44, 46 and the first to third main body sheets 50, 52, 54. In this state, it is wound around the outer periphery of the third main body sheet 54. Therefore, 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 56.

  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 56. That is, the resistance to bending rigidity is enhanced by the first front reinforcing layer 72 and the second front reinforcing layer 80 having the fiber direction of the reinforcing fibers in the axial direction. 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 the rear reinforcing sheet 48 at positions corresponding to the outer circumferences of the fourth tapered portion (intermediate tapered portion) 28 and the fifth tapered portion (rear tapered portion) 30 of the removed cored bar 20. Yes. At this time, since the rear reinforcing layer 74 is formed of a knitted sheet, the bending rigidity, torsional rigidity, crushing rigidity, etc. of the shaft 12 are reinforced.
On the other hand, only the first and second main body layers 76 and 78 exist in a portion adjacent to the front end side with respect to the rear reinforcing layer 74 of the shaft 12, and no rear reinforcing layer exists. Therefore, this portion is formed more easily than the portion on the rear end side of the shaft 12 in which the rear reinforcing layer 74 is disposed in addition to the first and second main body layers 76 and 78.
In particular, the portions of only the first and second main body layers 76 and 78 are formed at positions of 50% to 70% with respect to the total length L from the rear end 12b of the shaft 12. That is, only the first and second main body layers 76 and 78 are disposed on the front side of 50% of the entire length L of the shaft 12.
Therefore, when the golf club 10 is swung, the golf club 10 having high rigidity can be reliably controlled on the grip 16 side (rear end side), and the front portion (front end side) is more than the grip 16 side (hand side). Since it bends, it can make a hitting ball easy to go up.
Further, the outer diameter adjusting layer 74 a of the rear reinforcing layer 74 has an axial length direction length (axial length direction width) that is about 4% to 6% smaller than the entire length L of the shaft 12. For this reason, the presence of anisotropy occurring in the shaft 12 can be suppressed.

As described above, when the golf club 10 in which the head 14 and the grip 16 are fixed to the shaft 12 according to this embodiment is used, the portion on the grip 16 side adjacent to the front end side by having the rear reinforcing layer 74. It is formed higher than this layer. For this reason, when the golf club 10 is swung, the grip 16 side is provided with rigidity so that the golf club 10 can be easily controlled, and a portion adjacent to the front end side of the rear reinforcing layer 74 is gripped. It is possible to easily raise the hit ball by bending it compared to the 16 side.
Further, since the third taper portion (front taper portion) 26 and the fifth taper portion (rear taper portion) 30 have substantially the same inclination, the thickness of the rear reinforcement sheet 48 constituting the rear reinforcement layer 74 is constant. And efficient reinforcement can be performed.

  Next, a second embodiment will be described with reference to FIGS. This embodiment is a modification of the first embodiment.

As shown in FIG. 5, the metal core 120 according to this embodiment has a first taper portion 122, a second taper portion 124, and a third taper portion (first taper) in order from the front end 120a to the rear end 120b. Front taper portion 126, fourth taper portion (first intermediate taper portion) 128, fifth taper portion (first rear taper portion) 130, sixth taper portion 132, and seventh taper portion (second taper portion). It includes a front taper portion 134, an eighth taper portion (second intermediate taper portion) 136, a ninth taper portion (second rear taper portion) 138, and a straight portion 140.
That is, between the first taper portion 122 and the second taper portion 124, between the second taper portion 124 and the third taper portion (first front taper portion) 126, and between the third taper portion 126 and the fourth taper portion. (First intermediate taper portion) 128, between the fourth taper portion 128 and the fifth taper portion (first rear taper portion) 130, between the fifth taper portion 130 and the sixth taper portion 132, Between the sixth taper portion 132 and the seventh taper portion (second front taper portion) 134, between the seventh taper portion 134 and the eighth taper portion (second intermediate taper portion) 136, and between the eighth taper portion 136 and Between the ninth taper portion (second rear taper portion) 138 and between the ninth taper portion 138 and the straight portion 140, an annular displacement portion for changing the inclination of the outer peripheral surface of the cored bar 20, respectively. 123, 125, 127, 129, 131, 133, 135, 29,177 is formed.

Table 3 below shows the inclination (taper angle) of each taper portion with respect to the central axis C of the cored bar 120 and each taper portion (adjacent displacement portions 123, 125, 127, 129, 131) with respect to the total length L of the shaft 112. , 133, 135, 137, 139).

The metal core 120 of this embodiment is different from the metal core 20 of the first embodiment in the third taper portion (first front taper portion) 126, the fourth taper portion (first intermediate taper portion) 128, and the fifth. A taper portion (first rear taper portion) 130 is added. That is, the 1st taper part 122 and the 2nd taper part 124 of the metal core 120 of this embodiment are respectively corresponded to the 1st taper part 22 and the 2nd taper part 24 of the metal core 20 of 1st Embodiment. Further, the seventh taper portion (second front taper portion) 134, the eighth taper portion (second intermediate taper portion) 136, and the ninth taper portion (second rear taper portion) 138 of the metal core 120 of this embodiment are as follows. These correspond to the third taper part (front taper part) 26, the fourth taper part (intermediate taper part) 28, and the fifth taper part (rear taper part) 30 of the cored bar 20 of the first embodiment.
Therefore, the first taper part 122, the second taper part 124, the seventh taper part (second front taper part) 134, the eighth taper part (second intermediate taper part) 136 of the cored bar 120 of this embodiment, The main description of the ninth taper portion (second rear taper portion) 138 is omitted.

  The shaft 112 according to this embodiment includes first to third front reinforcing sheets 152, 154, 156, an intermediate reinforcing sheet 158, a rear reinforcing sheet 160, and first to third main body sheets 162, 164. 166 and a fourth front reinforcing sheet 168. These first to third front reinforcing sheets 152, 154, 156, intermediate reinforcing sheet 158, rear reinforcing sheet 160, first to third main body sheets 162, 164, 166, and fourth front reinforcing sheet 168 are A prepreg sheet having a constant thickness is used.

Table 4 below shows the fiber direction of the reinforcing fiber and the thickness of the prepreg sheet with respect to the cored bar 120 of each prepreg sheet constituting the shaft 112.

The first to third front reinforcing sheets 152, 154, and 156 and the fourth front reinforcing sheet 168 shown in Table 4 are the first to third front reinforcing sheets 42, 44, and 46 of the first embodiment. 4 The same prepreg sheet as the front reinforcing sheet 56 is used. As the rear reinforcing sheet 160, a prepreg sheet similar to the rear reinforcing sheet 48 of the first embodiment is used. As the first to third main body sheets 162, 164, and 166, prepreg sheets similar to the first to third main body sheets 50, 52, and 54 of the first embodiment are used.
In this embodiment, the intermediate reinforcing sheet 158 is a laminate of a prepreg sheet having a fiber direction of reinforcing fibers in the axial direction and a prepreg sheet having a fiber direction in the circumferential direction inclined by 90 degrees with respect to the axial direction. Is used. A prepreg sheet having a fiber direction in the circumferential direction is used for adjusting the crushing rigidity.

  As shown in FIG. 6, the first front reinforcing layer 172 is formed on the tip (one end) 120 a side of the cored bar 120 by the first to third front reinforcing sheets 152, 154, 156. The substantially triangular portion 152a of the first front reinforcing sheet 152 shown in FIG. 5 and the second and third front reinforcing sheets 154 and 156 are substantially square-shaped portions 154a and 156a, so that the outer diameter adjusting layer of the first embodiment is formed. An outer diameter adjusting layer 172a corresponding to 72a is formed. Therefore, the outer peripheral surface of the first front reinforcing layer 172 is substantially flush with the outer peripheral surface of the third taper portion (first front taper portion) 126 of the cored bar 120.

As shown in FIG. 5, the rear reinforcing sheet 160 is wound around the eighth taper portion (second intermediate taper portion) 136 and the ninth taper portion (second rear taper portion) 138. Therefore, as shown in FIG. 6, a rear reinforcing layer 176 is formed on the outer peripheral surfaces of the eighth tapered portion 136 and the ninth tapered portion 138.
At this time, an outer diameter adjusting layer 176a (corresponding to the outer diameter adjusting layer 74a of the first embodiment) is formed by the substantially triangular portion 160a (corresponding to the substantially triangular portion 48a of the first embodiment) of the rear reinforcing sheet 160. is doing. For this reason, the outer peripheral surface of the rear reinforcing layer 176 of the shaft 112 is substantially flush with the outer peripheral surface of the seventh tapered portion (second front tapered portion) 134 of the cored bar 120.

As shown in FIG. 5, the intermediate reinforcing sheet 158 is wound around the fourth taper portion (first intermediate taper portion) 128, the fifth taper portion (first rear taper portion) 130, and the sixth taper portion 132. Therefore, as shown in FIG. 6, an intermediate reinforcing layer 174 is formed on the outer peripheral surfaces of the fourth taper portion 128, the fifth taper portion 130, and the sixth taper portion 132.
At this time, the outer peripheral surface of the intermediate reinforcing layer 174 is substantially the same as the outer peripheral surface of the third taper portion (first front taper portion) 126 and the seventh taper portion (second front taper portion) 134 of the core metal 120. It is the same.

The intermediate reinforcing sheet 158 shown in FIG. 5 has substantially triangular portions 158a and 158b.
The substantially triangular portion 158 a on the front side of the intermediate reinforcing sheet 158 is wound around the fourth taper portion (first intermediate taper portion) 128 of the core metal 120, and the third taper portion (front taper portion) 126 of the core metal 120 is wound. It is used to make the outer peripheral surface flush with the outer peripheral surface of the intermediate reinforcing layer 174 wound around the fourth taper portion 128 and the fifth taper portion (rear taper portion) 130. That is, the substantially triangular portion 158a forms the outer diameter adjustment layer 174a.

A substantially triangular portion 158b on the rear side of the intermediate reinforcing sheet 158 is wound around the sixth taper portion 132 of the core metal 120, and the outer peripheral surface of the seventh taper portion (second front taper portion) 134 of the core metal 120; It is used to make the outer peripheral surface of the intermediate reinforcing layer 174 wound around the fifth taper portion 130 and the sixth taper portion 132 flush with each other. That is, the substantially triangular portion 158b forms the outer diameter adjustment layer 174b.
The outer diameter adjustment layer 174a is reduced in thickness as it approaches the displacement portion 127 of the core metal 120, and the thickness becomes substantially zero at the displacement portion 127, and the outer diameter adjustment layer 174b is reduced as it approaches the displacement portion 133 of the core metal 120. The thickness becomes substantially zero at the displacement portion 133. Note that the thinning here does not reduce the thickness of the intermediate reinforcing sheet 158 itself, and the substantially triangular portions 158a and 158b of the sheet 158 are respectively formed on the fourth taper portion 128 and the sixth taper portion 132 of the core metal 120. The same state as the state where the thickness is gradually reduced by winding.

  These outer diameter adjusting layers 174a and 174b can prevent a steep step from occurring on the inner peripheral side of the shaft 112 and can prevent a sudden change in strength. That is, the outer diameter adjusting layer 174a includes a portion of the shaft 112 corresponding to the outer peripheral position of the third tapered portion (first front tapered portion) 26 and the outer peripheral position of the fifth tapered portion (first rear tapered portion) 130. The rigidity difference with the part corresponding to can be moderated. The outer diameter adjusting layer 174b includes a portion of the shaft 112 corresponding to the outer peripheral position of the fifth tapered portion (first rear tapered portion) 130 and the outer peripheral position of the seventh tapered portion (second front tapered portion) 134. The rigidity difference with the part corresponding to can be moderated.

  As shown in Table 3, the lengths of the fourth taper portion (first intermediate taper portion) 128 and the eighth taper portion (second intermediate taper portion) 136, that is, the outer diameter adjustment of the intermediate reinforcing layer 174 are adjusted. The axial length of the layer 174a and the axial length of the outer diameter adjusting layer 176a of the rear reinforcing layer 176 are about 4% to 6% with respect to the total length L of the shaft 112, respectively, or the intermediate reinforcing layer 174 and the rear reinforcing layer. An axial width of about 6% to 10% with respect to the layer 176 is preferred. If the ratio is larger (longer) than this, anisotropy tends to occur due to the triangular sheets (substantially triangular portions 158a and 160a) of the intermediate reinforcing sheet 158 and the rear reinforcing sheet 160. On the other hand, when the ratio is small (short), a step is formed by the fourth taper portion 128 that is continuous with the third taper portion (first front taper portion) 126 and the fifth taper portion (first rear taper portion) 130. The step is formed by the eighth tapered portion 136 that is continuous with the seventh tapered portion (second front tapered portion) 134 and the ninth tapered portion (second rear tapered portion) 138. As a result, the difference in stiffness between adjacent positions in the axial direction of the shaft 112 changes too rapidly.

The first main body sheet 162 is wound around the outer periphery of the first to third front reinforcing sheets 152, 154, 156, the intermediate reinforcing sheet 158, and the rear reinforcing sheet 160. Therefore, as shown in FIG. 5, the first main body sheet 162 is directly wound around the cored bar 120 because the third taper portion (first front taper portion) 126 and the seventh taper portion (second front portion). Part taper part) 134.
At this time, the meandering amount of the reinforcing fiber on the outer periphery of the third taper portion 126 and the seventh taper portion 134 can be reduced. Therefore, the shaft 112 can obtain a desired stable strength.
Then, the second main body sheet 164 is wound around the outer periphery of the first main body sheet 162, and the first main body sheet 162 and the second main body sheet 164 form the first main body layer 178.
Further, the second main body layer 180 is formed by the third main body sheet 166 on the outer periphery of the first main body layer 178. Therefore, the outer peripheral surface of the second main body layer 180 has a certain taper angle with respect to the central axis C of the cored bar 20 (as described above, for example, an inclination of about 6/1000 to about 10/1000).

  The fourth front reinforcing sheet 168 is aligned with the tips of the first to third front reinforcing sheets 152, 154, 156 and the first to third main body sheets 162, 164, 166. And wound around the outer periphery of the third main body sheet 166. For this reason, the second front reinforcing layer 182 is formed by the fourth front reinforcing sheet 168.

Then, in the same manner as in the normal molding, from the outside of the second main body layer 180 and the second front reinforcing layer 182, clamping and molding are performed by taping, the core bar 120 and the shaft 112 are heat-cured, the core bar 120 is removed, and the taping tape is removed. The golf club shaft 112 can be obtained by removal, polishing, or the like.
Even if the golf club 10 is swung with the tips (the first front reinforcing layer 172 and the second front reinforcing layer 182) of the shaft 112 inserted into the hosel 14a of the head 14 and fixed, the shaft 112 is not moved. It can be maintained in a good state.

  An intermediate reinforcing layer 174 is formed by an intermediate reinforcing sheet 158 at positions corresponding to the outer circumferences of the fourth to sixth tapered portions 128, 130, 132 of the core metal 120 removed from the shaft 112, and the eighth and ninth tapered portions 136, 136 are formed. A rear reinforcing layer 176 is formed by a rear reinforcing sheet 160 at a position corresponding to the outer periphery of 138. At this time, the intermediate reinforcing layer 174 and the rear reinforcing layer 176 use prepreg sheets 158 and 160 having a constant thickness, so that the outer peripheral surfaces of the intermediate reinforcing layer 174 and the rear reinforcing layer 176, the third tapered portion 126, and the seventh Since the outer peripheral surface of the tapered portion 134 can be substantially flush with the step, it is possible to prevent a difference in strength between the intermediate reinforcing layer 174 and the rear reinforcing layer 176 from occurring.

Since the intermediate reinforcing layer 174 has the fiber direction of the reinforcing fiber in the axial length direction and the circumferential direction, the bending rigidity and the crushing rigidity are enhanced. Further, since the rear reinforcing layer 176 is formed of a knitted sheet, the bending rigidity, torsional rigidity, crushing rigidity and the like of the shaft 112 are enhanced.
On the other hand, only the first and second main body layers 178 and 180 exist in a portion between the intermediate reinforcing layer 174 and the rear reinforcing layer 176 of the shaft 112 and a portion in front of the intermediate reinforcing layer 174 (tip side). There is no layer. Therefore, a portion between the intermediate reinforcing layer 174 and the rear reinforcing layer 176 and a portion on the front side (front end side) of the intermediate reinforcing layer 174 include the intermediate reinforcing layer in addition to the first and second main body layers 178 and 180. 174 and the rear reinforcing layer 176 are more easily bent than the portion of the shaft 112 on which the rear reinforcing layer 176 is disposed.

Note that the rear reinforcing layer 74 of the shaft 12 of the first embodiment is preferably in the range of 50% to 70% from the rear end with respect to the total length L of the shaft 12, but in the shaft 112 of this embodiment, The total length of the intermediate reinforcing layer 174 and the rear reinforcing layer 176 is preferably in the range of 50% to 70% with respect to the total length L of the shaft 112. The axial length of the intermediate reinforcing layer 174 is preferably about 25% to 35% with respect to the total length L of the shaft 112, and the axial length of the rear reinforcing layer 176 is the total length of the shaft 112. It is preferable that it is about 25% to 35% with respect to L. The axial length of the intermediate reinforcing layer 174 may be longer than the axial length of the rear reinforcing layer 176, or vice versa.
Further, the third taper portion (first front taper portion) 126 and the seventh taper portion (second front taper portion) 134 of the shaft 112 are within a range of 12% to 25% with respect to the total length L of the shaft 112, respectively. Preferably there is.

  For example, when the total length of the intermediate reinforcing layer 174 and the rear reinforcing layer 176 is 50% with respect to the total length L of the shaft 112, the first taper portion 122 and the third taper portion (first front taper portion). It is preferable that the total length of 126 and the seventh tapered portion (second front tapered portion) 134 is 32% to 42% with respect to the entire length of the shaft 112.

When the third taper portion 126 of the metal core 120 is made as long as possible, the seventh taper portion 134 is shortened, so that the rigidity of the shaft 112 on the grip 16 side is maintained and the head 14 side of the shaft 112 is moved to the grip 16 side. It can be made easier to bend as compared. That is, it becomes easy to raise the hit ball.
Further, when the seventh tapered portion 134 is made as long as possible, the third tapered portion 126 is shortened, so that the rigidity on the grip 16 side is lower than the former, but the grip 16 side is also easily bent in addition to the head 14 side. Therefore, it is easy to raise the hit ball. Even in this case, if the rigidity of the rear reinforcing layer 176 is adjusted to be higher than that of the intermediate reinforcing layer 174, the shaft 112 is bent on the head 14 side while maintaining controllability on the grip 16 side, and the ball is hit. Can be easily raised.
In this embodiment, the case where one intermediate reinforcing layer 174 is formed has been described. However, two or more intermediate reinforcing layers 174 may be provided.

  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 described. Including implementation.

  C: central axis, L: shaft length, 10 ... golf club, 12 ... shaft, 12a ... tip, 12b ... rear end, 14 ... head, 14a ... hosel, 16 ... grip, 20 ... cored bar, 20a ... tip, 20b ... rear end, 22 ... first taper part, 24 ... second taper part, 26 ... third taper part (front taper part), 28 ... fourth taper part (intermediate taper part), 30 ... fifth taper part ( Rear taper part), 32 ... straight part, 23, 25, 27, 29, 31 ... displacement part, 42 ... first front reinforcing sheet, 44 ... second front reinforcing sheet, 46 ... third front reinforcing sheet, 48 ... rear reinforcing sheet, 48a ... substantially triangular portion, 50, 52, 54 ... main body sheet, 56 ... fourth front reinforcing sheet, 72 ... first front reinforcing layer, 72a ... outer diameter adjusting layer, 74 ... rear part Reinforcing layer, 74a ... outer diameter adjusting layer, 76 ... first body layer, 8 ... second body layer, 80 ... second front reinforcing layer.

Claims (4)

Between the front taper portion on the front side in the axial direction having a common central axis and the rear taper portion on the rear side in the axial direction with respect to the front taper portion, an intermediate taper portion having a gentle gradient with respect to these taper portions is provided. A golf club shaft formed by winding a fiber-reinforced prepreg in which a reinforcing fiber is impregnated with a synthetic resin with respect to a continuously disposed tapered cored bar,
A reinforcing prepreg is wound from the intermediate taper portion of the metal core to the rear taper portion to form a reinforcing layer, and an outer diameter adjusting portion is formed at the front portion of the reinforcing layer located at the intermediate taper portion, The taper of the outer peripheral surface of the reinforcing layer is substantially the same as the taper of the front taper part,
A golf club shaft comprising a main body layer wound around the front taper portion and the reinforcing layer.   2. The golf club shaft according to claim 1, wherein a taper angle of the front taper portion and a taper angle of the rear taper portion are substantially the same.   The said intermediate taper part is located in 50% to 70% from the rear end of the shaft full length L, and has a width of 6% to 10% of the reinforcing layer. Golf club shaft.   The fiber direction of the reinforcing fiber of the innermost main body layer among the main body layers is inclined with respect to the axial length direction of the shaft. Golf club shaft.

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