Golf club shaft and golf club

Abstract

To provide a golf club shaft which is lightweight and suppresses the dispersion of a ball when hit. [Solution] The present invention has a shaft body formed by winding multiple prepreg sheets made of fiber-reinforced resin material in which reinforcing fibers are impregnated with synthetic resin, and a plain weave layer 30A made of plain weave prepreg sheets 30 in which spread yarns are woven at 0° and 90° to the axial direction of the shaft 10 is provided throughout the axial direction, and prepreg sheets 21, 22, 23 made of fiber-reinforced resin material and a prepreg sheet 33 made of fiber-reinforced resin material are wound on the inner and outer layer sides of the plain weave layer 30A.

Description

[Technical Field]

[0001] The present invention relates to a golf club shaft, and more particularly to a golf club shaft capable of suppressing ball dispersion when hit, and a golf club equipped with such a shaft. [Background technology]

[0002] Conventionally, shafts used in golf clubs are formed by winding multiple prepreg sheets, which are made of reinforcing fibers impregnated with synthetic resin, around a mandrel, heating the mandrel to harden the synthetic resin, and then removing the mandrel. Prepreg sheets with various configurations are used, taking into consideration the feel, strength, pattern, etc.

[0003] For example, Patent Document 1 discloses a golf club shaft that has a bias layer in which reinforcing fibers are arranged at an angle in the longitudinal direction of the shaft, a straight layer in which reinforcing fibers are arranged along the axial direction, and a reinforcing layer in which reinforcing fibers are knitted on the tip side. With this golf club shaft, the tip side where the head is attached is reinforced, preventing damage and improving impact resistance.

[0004] Patent Document 2 discloses a golf club shaft in which spread yarns are woven in a cross pattern, a prepreg sheet having a metal vapor-deposited surface is disposed on the prepreg sheet, and a glass fiber prepreg sheet is wound on top of the prepreg sheet. With this configuration, the brilliance of the metal is visible, thereby improving the appearance. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Jpn. Appl. KOKAI Publication No. 05-056167 [Patent Document 2] Patent Publication No. 2022-082042 Summary of the Invention [Problem to be solved by the invention]

[0006] The golf club shafts disclosed in the above-mentioned Patent Documents 1 and 2 are lightweight shafts, but do not fully consider the specific configuration and arrangement of prepreg sheets that suppress ball dispersion when hit.

[0007] SUMMARY OF THE INVENTION An object of the present invention is to provide a lightweight golf club shaft that reduces ball dispersion when hit, and a golf club having such a shaft. [Means for solving the problem]

[0008] This invention is a golf club shaft having a shaft body formed by winding multiple prepreg sheets made of fiber-reinforced resin material in which reinforcing fibers are impregnated with synthetic resin, characterized in that a plain weave layer made of plain weave prepreg sheets in which spread yarns are woven at 0° and 90° to the axial direction of the shaft is provided throughout the axial direction, and fiber-reinforced resin prepreg sheets are wound on the inner and outer layers of the plain weave layer.

[0009] The golf club shaft described above includes a plain weave layer formed by winding a spread yarn plain weave prepreg sheet in which reinforcing fibers made of spread yarns are woven in the 0° and 90° directions relative to the axial direction of the shaft. This spread yarn plain weave prepreg sheet is provided throughout the axial direction of the shaft, allowing the characteristics of the plain weave layer to be exhibited throughout the entire shaft, including the narrowed-diameter portion. A spread yarn plain weave prepreg sheet made of spread yarns reduces the amount of unevenness, allowing for a thinner wall. Even with a plain weave, the use of spread yarns, in particular, allows for an efficient increase in the amount of fibers in the 90° direction without increasing the sheet thickness or the amount of fibers in the 0° direction, thereby contributing to a lighter shaft. Furthermore, because prepreg sheets made of a fiber-reinforced resin material are wound on the inner and outer layers of such a plain weave layer, undulation and meandering of the spread yarns in a plain weave state during the winding process are suppressed, stabilizing flexibility and strength. Therefore, vibration and twisting of the molded shaft when hitting the ball are suppressed, and the directionality of the hit ball can be stabilized.

[0010] The present invention is also characterized by a golf club having the shaft configured as described above. Golf clubs include iron types, wood types (drivers, fairway woods, utilities), putters, etc. [Effects of the Invention]

[0011] According to the present invention, it is possible to obtain a lightweight golf club shaft that reduces the variation in ball strikes, and a golf club having such a shaft. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a diagram showing an example of a golf club and an example of a pattern of a prepreg sheet that constitutes the shaft of the golf club. [Figure 2] Cross-sectional view of the shaft. [Figure 3] Enlarged view of Figure 2. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of a golf club shaft (also referred to as a shaft) and a golf club will be described with reference to the accompanying drawings. FIG. 1 shows an example of a golf club and an example of a pattern of a prepreg sheet that constitutes the shaft of the golf club, FIG. 2 is a cross-sectional view of the shaft, and FIG. 3 is an enlarged view of FIG.

[0014] The golf club 1 according to this embodiment is configured by attaching a head 80 to the tip of a shaft 10 and attaching a grip 90 to the base end of the shaft 10. The head 80 shown in the figure is a wood type, but it can be applied to various types of golf clubs, such as utility types, iron types, and putter types.

[0015] A hosel portion 81 into which the tip of the shaft 10 is fitted and secured is integrally formed on the crown portion of the head 80, and the tip of the shaft 10 is fitted and secured in the opening of the hosel portion 81. In FIG. 1, the symbol P1 indicates the upper end position of the hosel 81, and the symbol P2 indicates the wing opening of the grip 90.

[0016] As is well known, the shaft 10 is formed by winding a plurality of prepreg sheets made of a fiber-reinforced resin material, such as carbon fiber, glass fiber, or aramid fiber, impregnated with a thermoplastic resin or a thermosetting resin, around a core (omitted in FIG. 1 ), and then undergoing well-known processes such as heating and core removal. In the following description, the prepreg sheet wound from the tip to the butt end of the shaft 10 will be referred to as the main body sheet (main body). This main body sheet not only refers to the portion wound from the tip edge to the high end edge of the shaft 10, but also includes the portion excluding the portion to which the grip of the shaft is attached and / or the portion to which the hosel of the head is attached. The main body sheet constitutes the main layer that forms the entire length L of the shaft.

[0017] Main body sheets (prepreg sheets) 21, 22, and 23 are sequentially wound around a core bar (not shown). These main body sheets 21, 22, and 23 constitute the inner main body layer 20A that is wound on the inner layer side of the shaft, and have an axial length corresponding to the overall length L of the shaft 10. Alternatively, these main body sheets 21, 22, and 23 may be wound around a core bar, heated, removed from the core, and cut off the ends as necessary to form them into the above-mentioned length L.

[0018] The main body sheet 21, which is the innermost layer of the main body sheets, is formed by laminating together a first oblique sheet in which the reinforcing fibers are oriented at +45° to the axial direction and a second oblique sheet in which the reinforcing fibers are oriented at -45° to the axial direction. This main body sheet 21 is cut so that it is wound with 2 to 3 plies at the distal end and 1 to 2 plies at the proximal end (preferably, an integer number of plies, rather than an odd number such as 1.5 plies, and a slight over-ply is set to prevent gaps at the circumferential edges). In this case, the number of plies may be increased or decreased depending on the thickness of the sheet. That is, for thin sheets, multiple layers may be used, and for thick sheets, fewer layers may be used (the same applies to the main body sheets below).

[0019] The main body sheet 22 to be wound on top of it is cut so that the reinforcing fibers are aligned in the axial direction and wound with 1 to 1.05 plies at the tip end and 1 to 1.05 plies at the base end. The main body sheet 23 to be wound on top of the main body sheet 22 is cut so that the reinforcing fibers are aligned in the axial direction and wound with 1 to 1.05 plies at the tip end and 1 to 1.05 plies at the base end. Since gaps at the edge of the wound main body sheets 22 and 23 are undesirable in appearance, it is preferable to set them so that there is a slight over-ply.

[0020] Among the main body sheets wound on the inner layer side, the main body sheets 22 and 23, in which the reinforcing fibers are aligned in the axial direction, contribute to improving bending rigidity. Furthermore, the main body sheet 21, in which the reinforcing fibers are oriented in the cross direction, contributes to improving torsional rigidity. In this case, the most effective way to improve torsional rigidity is to orient the reinforcing fibers at an angle of ±45°, but the angle of inclination is not limited to ±45°.

[0021] The main body sheet forming the inner main body layer 20A may be one in which reinforcing fibers are aligned in the circumferential direction. Such a main body sheet contributes to improving the crushing strength. Regarding the winding position of such a main body sheet in which reinforcing fibers are aligned in the circumferential direction, it is preferable to wind it on the inside in consideration of winding workability. Furthermore, if the crushing strength is sufficiently ensured by the thickness, it may not be wound. Conversely, if the crushing strength is insufficient, two or more plies may be wound. Furthermore, it may be wound in a manner that distributes, for example, one ply at a time in the thickness direction.

[0022] A reinforcing sheet 25, in which reinforcing fibers are aligned in the axial direction, is wound around the tip region of the shaft 10 (the tip side where the head is attached). The reinforcing sheet 25 may be wound within a range of 200 mm or less from the tip position, taking into consideration the location where the head is attached. The reinforcing sheet 25 may be wound in the innermost layer, intermediate layer, or outermost layer, as shown in the figure, or may be wound at multiple positions in the thickness direction (in this embodiment, a reinforcing sheet 27 is also wound around the outermost layer). Furthermore, the reinforcing fibers used in the reinforcing sheets 25 and 27 are oriented in the axial direction, but may also be oriented in the circumferential direction or woven in a cross pattern. The reinforcing sheets 25 and 27 may be omitted.

[0023] A reinforcing sheet 26, made of reinforcing fibers aligned in the circumferential direction, is wound around the rear end region of the shaft (the rear end side where the grip 90 is attached). Taking into account the length of the grip to be attached, the reinforcing sheet 26 may be wound up to a range of 310 mm or less from the rear end position. The reinforcing sheet 26 may be wound in the innermost layer, intermediate layer, or outermost layer, as shown in the figure, or may be wound at multiple positions in the thickness direction. Furthermore, the reinforcing fibers of the reinforcing sheet 26 are oriented in the circumferential direction to improve crush strength, but they may also be oriented in the axial direction or woven in a cross pattern. The reinforcing sheet 26 may be omitted.

[0024] On the outer layer side of the main body sheet 23, a plain weave prepreg sheet (open fiber plain weave prepreg sheet) 30 in which spread fiber yarns are woven in a cross shape is wound. As is well known, the spread yarn is formed by thinly and uniformly spreading thousands to tens of thousands of carbon fiber bundles, and as an example, when a spread yarn plain weave prepreg sheet made by weaving these into a plain weave is compared with a plain weave prepreg sheet made by weaving conventional carbon fiber bundles into a plain weave, the spread yarn has the following characteristics: it is thin, light, has less unevenness, and has a small fiber angle (the oblique angle formed when two fibers (warp and weft) in different directions cross each other). Therefore, compared to general prepreg sheets, the spread yarn has the characteristics of being excellent in resin impregnation and less susceptible to delamination, and contributing to lighter weight and thinner shafts.

[0025] By winding the spread yarn plain weave prepreg sheet 30, a plain weave layer 30A made of plain woven spread yarns is formed. The spread yarn plain weave prepreg sheet 30 is wound over the entire length of the shaft in the axial direction, and the plain weave layer 30A is provided continuously without interruption over the axial direction of the shaft body. In this case, the present invention also includes a case where the plain weave layer 30A is provided continuously over the entire axial direction except for at least the grip portion and the hosel portion.

[0026] Therefore, the plain weave layer 30A formed by winding the spread yarn plain weave prepreg sheet 30 can exhibit the characteristics of the plain weave layer over the entire length of the shaft, including the narrowed diameter portion. In this embodiment, the plain weave layer 30A is wound over the entire length of the shaft, excluding the grip portion, and is cut so that there are 1 to 1.05 plies on the tip end side and 1 to 1.05 plies on the base end side.

[0027] In this embodiment, the spread yarns are cross-woven at angles of 0° and 90° to the axial direction and are impregnated with resin to form a spread yarn plain weave prepreg sheet 30. A plain weave prepreg sheet made of spread yarns has good resin impregnation properties, making it difficult for delamination to occur, and the synthetic resin and reinforcing fibers are evenly dispersed, improving strength. When such a spread yarn plain weave prepreg sheet is wound, the amount of unevenness is reduced, allowing for a thinner wall. That is, since the thickness can be made thinner and lighter than that of a general prepreg sheet, it is preferable to use a thickness H of 0.03 mm or more and 0.1 mm or less. The basis weight is 40 to 80 g / m 2 This makes it possible to reduce the weight while maintaining the required strength.

[0028] Furthermore, by using plain weave spread yarns, it is possible to efficiently increase the amount of fibers in the 90° direction without increasing the thickness of the sheet or the amount of fibers in the 0° direction, which contributes to reducing the weight of the shaft.

[0029] It should be noted that the spread yarn plain weave prepreg sheet 30 may be one in which the spread yarns are woven in a cross shape, and may have some deviation from 0° or 90° with respect to the axial length direction of the shaft (for example, an error of about ±5° is acceptable). Furthermore, the above-described spread yarn plain weave prepreg sheet 30 can be modified as appropriate, for example, oriented at ±45° other than 0° or 90°, and the weaving method can be plain weave, satin weave, twill weave, or the like.

[0030] A prepreg sheet made of a fiber reinforced resin material is wound around the surface side (outer layer side) of the spread yarn plain weave prepreg sheet 30. In this embodiment, a glass fiber prepreg sheet 33 is used, and the glass fiber prepreg sheet 33 forms an outer main body layer (glass fiber layer) 33A on the outer layer side of the spread yarn plain weave prepreg sheet 30. Therefore, a prepreg sheet constituting the inner main body layer 20A is wound around the inner layer side of the plain weave layer 30A made of the spread yarn plain weave prepreg sheet 30, and a prepreg sheet constituting the outer main body layer 33A is wound around the outer layer side.

[0031] That is, plain weave layer 30A made of spread yarn plain weave prepreg sheet 30 is interposed between inner main body layer 20A and outer main body layer 33A formed by winding a fiber reinforced resin material.

[0032] The glass fiber prepreg sheet 33 is made of woven glass fibers, but may be unidirectionally aligned glass fibers (also called a UD sheet in which the reinforcing fibers are unidirectionally aligned) or a stack of UD sheets with reinforcing fibers oriented in different directions. Furthermore, any material that prevents the plain weave layer 30A from meandering or displacing may be used instead of glass fiber, and carbon fiber may also be used.

[0033] The main body sheet constituting the outer main body layer is cut so that it is wound with 2.00 to 2.05 plies at the tip end and 2.00 to 2.05 plies at the base end. In addition, to prevent deformation when hitting the ball, it is preferable to wind a UD sheet with carbon fibers aligned in the axial direction to improve bending rigidity.

[0034] As described above, since the prepreg sheets made of fiber reinforced resin material are wound on the inner and outer layer sides of the plain weave layer 30A made of spread yarns, undulation and meandering of the plain weave spread yarns during the winding operation are suppressed, and flexibility and strength are stabilized. Therefore, vibration and twisting of the molded shaft when hitting a ball are suppressed, and the directionality of the hit ball can be stabilized.

[0035] In general, since the prepreg sheet in the outer layer than the fibrillated yarn plain weave prepreg sheet 30 is polished, if the layer outside it (glass fiber layer 33A in this embodiment) has a tendency to be thick, it will not be polished up to the plain weave layer 30A, that is, it is possible to suppress the impairment of the effect of the plain weave sheet. Further, regarding the layer outside the fibrillated yarn plain weave prepreg sheet 30 (glass fiber layer 33A), by making its thickness H < H1, it becomes difficult for the fibrillated yarn plain weave prepreg sheet 30 to curl up, and a stable winding state can be brought about.

[0036] Specifically, the glass fiber layer (the layer outside the plain weave layer) 33A has a thickness H1 in the range of 1 to 4 times, preferably 2 to 3 times, with respect to the thickness H of the plain weave layer 30A formed by the plain weave prepreg sheet. By doing so, the undulation and meandering of the fibrillated yarn in the plain weave state are effectively suppressed, a stable winding state is obtained, and the stabilization of strength can be achieved.

[0037] In this embodiment, as shown in FIG. 1, for the glass fiber prepreg sheet 33, the edge 33c of the glass fiber prepreg sheet 33C cut at the central position in the axial direction of the shaft abuts against the edge 33d of the carbon fiber prepreg sheet 33D having carbon fibers, or is somewhat overlapped and integrated in the axial length direction to form the main body sheet.

[0038] That is, by winding UD prepreg sheets inside and outside the plain weave layer 30A and forming at least the tip side (the head side where hitting the ball is made) from the center of the shaft body with carbon fibers, it is possible to effectively suppress the variation in weight and the variation in vibration frequency and suppress the variation in hitting the ball.

[0039] Next, between a golf club using a shaft provided with the plain weave layer made of the above-described fibrillated yarn and a golf club using a shaft without using the fibrillated yarn, the results of a hitting test conducted with a robot tester regarding the variation in hitting the ball are shown in Table 1 below. The two golf clubs used had heads with the exact same configuration (wood clubs), and the shafts were prepared with one equipped with a plain woven layer made of spread fiber yarn, and the other equipped with a main body layer made of normal carbon fiber instead of spread fiber yarn, with the same specifications for overall length, overall weight, swing balance, etc. In addition, the balls used, hitting position, head speed, etc. were all hit under the same conditions, and the degree of variation in the carry position (ball landing position) of each of the four hit balls was shown in Table 1 below.

[0040] [Table 1]

[0041] The ball surrounded by the small oval is the position where the ball fell when hit with a shaft using a spread yarn plain weave prepreg sheet, and the ball surrounded by the large oval is the position where the ball fell when hit with a shaft not using the spread yarn plain weave prepreg sheet. As can be seen from this trial hitting test, by using spread yarn and prepreg sheets made of a fiber reinforced resin material on the inner and outer layer sides thereof, the behavior of the shaft is stabilized, and the result that a golf club with reduced deviation of the impact point and loss of impact when hitting the ball and suppressed variation in hit balls can be obtained is obtained.

[0042] Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and can be modified in various ways.

[0043] By providing the above-mentioned spread yarn plain weave prepreg sheet continuously over the entire axial direction of the shaft, particularly over the axial length of the shaft body, it is possible to stabilize the flexibility and strength of the entire shaft. As a result, the molded shaft is suppressed from vibration and twisting when hitting a ball, and the direction of the hit ball can be stabilized. In this case, by providing the plain weave layer 30A made of the spread yarn plain weave prepreg sheet 30 over at least the range from the upper end P1 of the hosel 81 of the head to the wing opening P2 of the grip 90 when the head 80 and the grip 90 are attached to the shaft 10, it is possible to efficiently suppress vibration and twisting when hitting a ball while reducing the amount of spread yarn plain weave prepreg sheet used.

[0044] The present invention also requires that a prepreg sheet made of a plain woven spread fiber prepreg sheet be sandwiched between prepreg sheets made of a fiber-reinforced resin material, and that the arrangement of the reinforcing fibers, thickness, number of windings, etc. of each prepreg sheet be appropriately modified. [Explanation of symbols]

[0045] 1. Golf club 10 shaft 20A main body layer 21, 22, 23 Main seat 30 Spread yarn plain weave prepreg sheet (plain weave prepreg sheet) 30A plain weave layer 33 Glass fiber prepreg sheet 33A Glass fiber layer 80 head 90 Grip

Claims

1. A golf club shaft having a shaft body formed by winding a plurality of prepreg sheets made of a fiber-reinforced resin material in which reinforcing fibers are impregnated with a synthetic resin, a plain weave layer made of a plain weave prepreg sheet in which spread yarns are woven in directions of 0° and 90° with respect to the axial direction of the shaft is provided over the entire axial area, A prepreg sheet made of a fiber reinforced resin material is wound on the inner layer side and the outer layer side of the plain weave layer. Golf club shaft.

2. 2. The golf club shaft according to claim 1, wherein the plain weave layer made of the plain weave prepreg sheet is provided continuously along the axial length of the shaft body.

3. 2. The golf club shaft according to claim 1, wherein the plain weave layer made of the plain weave prepreg sheet is provided over at least the range from the upper end of the hosel of the head to the wing opening of the grip when the head and the grip are attached to the shaft.

4. 2. The golf club shaft according to claim 1, wherein an outer UD (unidirectional fiber) prepreg sheet having reinforcing fibers aligned in a direction parallel to the axial direction of the shaft is wound around the outer layer side of the plain woven prepreg sheet.

5. 5. The golf club shaft according to claim 4, wherein the outer UD prepreg sheet is made of carbon fiber at least in a portion closer to the tip end than the center of the shaft body.

6. An inner UD prepreg sheet, in which reinforcing fibers are aligned in a direction parallel to the axial direction of the shaft, is wound on the inner layer side of the plain woven prepreg sheet, 5. The golf club shaft according to claim 4, wherein the plain woven layer is sandwiched between an inner layer made of the inner UD prepreg sheet and an outer layer made of the outer UD prepreg sheet.

7. 2. The golf club shaft according to claim 1, wherein a glass fiber prepreg sheet made by weaving glass fibers is provided on the outer layer side of the plain woven prepreg sheet, closer to the grip side than the center of the shaft body.

8. The thickness of the plain woven prepreg sheet is 0.03 mm or more and 0.1 mm or less, and the weight per unit area is 40 to 80 g / m 2 2. The golf club shaft according to claim 1, wherein:

9. A golf club comprising the golf club shaft according to any one of claims 1 to 8.

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