JP2010246823A - Method for manufacturing golf club shaft made of fiber-reinforced resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a golf club shaft made of a fiber-reinforced resin without losing fundamental properties for the shaft, which is excellent in designability as well. <P>SOLUTION: The method for manufacturing the golf club shaft made of the fiber-reinforced resin, wherein the shaft includes: layers formed by winding reinforced-fiber prepregs (21-23, 25-27) in which a plurality of reinforced fibers are arranged in one direction and impregnated with the resin; and layers formed by winding at least one layer of multi-axial fabrics (24) are wound. In molding, at least one of the prepregs (21-23, 25-27) to have the multi-axial fabrics (24) laminated is previously laminated with the multi-axial fabric (24) to become integrated. After the lamination, the integrated piece is wound around a mandrel (10) and shaped. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a golf club shaft comprising a fiber reinforced resin layer.

  The golf club shaft is the most important performance required to increase the flight distance and stabilize the directionality in the game of golf. In recent years, the importance of the design has also increased. In the background, conventional golf clubs have been manufactured and sold as a golf club head, shaft, and grip as one body, but since each of them has been selected as one's preference and assembled as a golf club, “custom-made” has progressed, It is mentioned that the tendency to request differentiation in the appearance of golf clubs has increased.

  The most widely used technique for improving the design of a golf club shaft is to differentiate it by painting. Conventionally, it was painted in a single color such as black, but in order to improve the design, it is differentiated from other shafts by applying two or more colors using gradation, etc., and also by applying multicolor printing. In recent years, shafts have become mainstream.

  However, such differentiation by painting, it is necessary to paint several layers to give a change in color, the process becomes longer, the weight of the shaft by painting, the outer diameter becomes thicker, etc. The problem is that it has a considerable influence on the performance of the shaft.

  On the other hand, in patent document 1 (Unexamined-Japanese-Patent No. 2002-191735), the low elastic fiber resin layer which arrange | positions a metal wire layer on the surface layer of the golf club shaft which consists of a fiber reinforced resin layer, and can see through on it. A method for manufacturing a golf club shaft is disclosed.

  According to Patent Document 1, a golf club shaft having a three-dimensional depth and excellent in design can be manufactured. Certainly, according to this method, it is possible to manufacture a golf club shaft having a three-dimensional depth, which is excellent in design, so there is no need for complicated coating, and it is possible to prevent an increase in weight due to coating. Since the specific gravity of the metal wire layer is larger than that of the reinforced resin layer, the weight increases due to the provision of the metal wire layer, and depending on the type of the metal wire, the metal wire itself is too rigid and difficult to wind. Have a problem.

  On the other hand, for example, in Patent Document 2 (Japanese Patent Laid-Open No. 7-241359) and Patent Document 3 (Japanese Patent Laid-Open No. 2006-61473), as a part of the shaft material, the weft is in a direction perpendicular to the axis of the shaft material. It is disclosed that a triaxial woven fabric layer whose direction and inclined yarn are inclined with respect to a coaxial line is used in combination with a normal fiber reinforced resin layer.

  In Patent Document 2, a triaxial fabric portion is provided in a fixed length portion on the butt side of a shaft material by interposing a triaxial fabric layer between an inner layer prepreg and an outer layer prepreg, and the innermost layer on the tip side of the shaft material. In addition, a tip reinforcing layer having a higher bending rigidity than that of the intermediate portion is provided as a tip reinforcing portion, and cutting is performed with different cutting lengths at the tip of the triaxial fabric portion and the tip reinforcing portion. Proposes to manufacture golf club shafts with different tone.

  Further, according to Patent Document 3, a thermosetting resin torsional rigidity holding layer including carbon fibers obliquely crossed in the longitudinal direction of the shaft, and a thermosetting resin including carbon fibers aligned parallel to the longitudinal direction. The torsional rigidity retaining layer is formed of a prepreg obtained by impregnating a plain woven fabric with a thermosetting resin so that the warp and the weft are obliquely crossed in the longitudinal direction of the shaft. A plain woven fabric layer 11 wound and cured in a straight line, and a triaxial woven fabric layer 12 in which a triaxial fabric is wound and cured on the shaft so that the weft is parallel or perpendicular to the longitudinal direction of the shaft. . Thereby, the flight distance and the direction stability are good and a satisfactory flight distance can be secured, and the golf club shaft can be provided which is excellent in hitting and particularly suitable for an iron club including a putter.

  By the way, the multiaxial woven fabric made of carbon fiber as described above is soft and flexible when it is wrapped around a mandrel or the like, so that the orientation angle of the fiber is likely to be shifted, and it is difficult to wind it alone. . If the fiber direction is deviated, desired rigidity and strength cannot be exhibited. Furthermore, for example, when a glass fiber reinforced layer is provided in the outermost layer so that the multiaxial woven fabric in the inner layer can be seen through, the fiber direction is disturbed as described above, and the characteristic three-dimensional woven fabric of the folded multiaxial woven fabric has The structure is broken, and it is visually impaired.

  In addition, since the multiaxial fabric has a void portion in its structure, voids are formed when it is formed on the shaft, which may reduce the mechanical strength of the shaft.

  In general, reinforcing fiber fabrics have high draping properties, so that they can be easily wound around a tubular body. However, as described above, the texture is likely to shift, and when a multiaxial fabric is used for the outermost layer, the texture is reduced during polishing. Since it was shaved, it had a problem that it was difficult to adopt it in terms of strength and design.

JP 2002-191735 A JP-A-7-241359 JP 2006-61473 A

  The present invention has been made in view of the above circumstances, and there is provided a method for producing a golf club shaft made of fiber reinforced resin having excellent design properties without impairing the basic performance of the golf club shaft. It is intended to provide.

When the multiaxial woven fabric is applied to the golf club shaft, as described above, the multiaxial woven fabric is too soft and the orientation angle of the reinforcing fibers is disturbed, making it difficult to produce a high quality golf club shaft.
In order to solve this problem, the present invention employs the following configuration.
Namely, a shaft for a fiber reinforced resin golf club comprising a layer formed by winding a prepreg sheet in which a plurality of reinforcing fibers are aligned in one direction and impregnated with a resin, and a layer formed by winding one or more multiaxial fabrics. In this manufacturing method, the multiaxial woven fabric and the reinforcing fiber prepreg are preliminarily bonded and integrated, and this is wound around a mandrel and molded.

  It is preferable to use a carbon fiber prepreg or a glass fiber prepreg as the reinforcing fiber prepreg to be pre-adhered to the multiaxial fabric, and preferably the resin content of the reinforcing fiber prepreg to be pre-adhered to the multiaxial fabric is 30% by weight or more. . Normally, a multiaxial fabric is pre-adhered to a carbon fiber prepreg and wound in a tubular shape. However, when particularly emphasizing design, the multiaxial fabric is pre-adhered to the glass fiber prepreg and the glass fiber prepreg is the outermost layer. Wrap like so.

  According to the method for manufacturing a fiber reinforced resin golf club shaft of the present invention, when a multiaxial woven fabric is wound into a tubular shape, the multiaxial woven fabric is wound on the other reinforcing fiber prepreg in advance and then integrated together. It can be easily wound without disturbing the orientation of the reinforcing fibers to be constituted. In addition, because it can be wound without disturbing the orientation of the reinforcing fiber in this way, high designability can be realized in the fiber reinforced resin layer derived from the three-dimensional structure peculiar to multiaxial fabrics, and a complicated coating Excellent design appearance can be obtained without having to In addition, since the multiaxial fabric has multi-directional fibers, a high-quality golf club shaft can be produced without impairing the basic performance of the golf club shaft.

  When the multiaxial woven fabric is preliminarily bonded to the reinforcing fiber prepreg, it is usually difficult for the multiaxial woven fabric to stick to the reinforcing fiber prepreg to be preliminarily bonded. Therefore, it is preferable to increase the resin content of the reinforcing fiber prepreg. The resin content is preferably 30% or more, more preferably 33% or more. By affixing a multiaxial woven fabric to the reinforcing fiber prepreg having such a resin content, the resin is surely impregnated into the multiaxial woven fabric during the molding process, and voids are not formed in the multiaxial woven fabric layer when the shaft is completed. Can do.

  When designability is important, placing the glass fiber prepreg on the outermost layer not only allows the inner multiaxial fabric to be seen through, but also damages the multiaxial fabric during polishing after molding. As a golf club shaft, high quality is guaranteed and the design is excellent.

  Hereinafter, with reference to the drawings, the configuration and operational effects of the present invention will be specifically described with preferred embodiments.

It is explanatory drawing which shows the cutting shape of the prepreg which shows 1st Example of the shaft for golf clubs of this invention, and the winding order to a mandrel. It is a schematic explanatory drawing of a mandrel. It is explanatory drawing which shows the cutting shape of the prepreg which shows 2nd Example of the shaft for golf clubs of this invention, and the winding order to a mandrel. It is an organization chart of the 4-axis textile which shows an example of the multiaxial textile used for the above-mentioned example.

  The golf club shaft manufacturing method of the present invention is for a golf club comprising a plurality of fiber reinforced resin layers which are sequentially wound and laminated around a mandrel with a plurality of prepregs having a predetermined cut shape and dimensions. Manufacture shaft. For example, the first to seventh wound sheets having a cut shape and dimensions as shown in FIG. 1 are sequentially wound around a predetermined position in the axial direction of the mandrel, and then heat-cured to form a plurality of fiber reinforced resin layers. A golf club shaft is manufactured.

  According to FIG. 1, the reinforcing fibers of the fiber reinforced resin layer have two prepregs 21 oriented in a direction of ± 45 ° with respect to the shaft axis direction at a small diameter end of 9 mm so as to deviate from the outer circumference of the mandrel 10, The first wrapping sheet in which the respective prepregs are bonded together is wound around the mandrel 10 with the large diameter end shifted by 21 mm, and a bias layer is formed in the innermost layer. A second reinforcing sheet composed of one prepreg 22 oriented in the axial direction is wound around the end of the shaft with a length of 300 mm to form a tip reinforcing layer. Next, a third wrapping sheet composed of a single prepreg 23 in which the reinforcing fibers of the fiber reinforced resin layer are substantially oriented in the shaft axial direction is wound over the entire shaft length (1165 mm) to form a first straight layer.

  After the first straight layer is formed, a 4-axis fabric (multi-axis fabric) 24 is wound as a fourth winding sheet. As shown in FIG. 4, the four-axis woven fabric 24 is composed of warp yarns 24a and weft yarns 24b crossing 90 °, and first and second diagonal yarns 24c and 24d arranged facing + 45 ° and −45 ° directions. This is a woven fabric having four yarns as constituent yarns. In this specification, a 4-axis woven fabric is taken as an example of a multi-axial woven fabric. However, for example, a triaxial woven fabric described in Patent Documents 2 and 3 or a multi-axial woven fabric higher than that can be used. . The yarn used in these woven fabrics can be a flat yarn composed of a large number of filaments having a small fineness and parallel fiber directions in order to prevent the crimp height from increasing at the intersection of the yarns.

Since the multiaxial fabric having such a structure is soft and the yarns are easily displaced from each other, it is difficult to wind the yarn directly around a tube.
Therefore, in the present invention, the four-axis fabric 24 is bonded in advance to another reinforcing fiber prepreg in a sheet state. In this way, the four-axis woven fabric bonded to the reinforcing fiber prepreg has no inter-fiber deviation, the orientation of the woven fabric is stable without changing its orientation angle, and if it is wound together with the reinforcing fiber prepreg bonded to the mandrel 10, a stable woven fabric is obtained. It can be easily wound while maintaining the structure.

  According to the example of FIG. 1, one prepreg 25 which is a fifth wound sheet in which the reinforcing fibers of the fiber reinforced resin layer constituting the second straight layer of the four-axis fabric 24 are substantially oriented in the shaft axis direction. Are pasted together in advance. At this time, when the resin content of the prepreg 25 is equal to the resin content of the other prepregs, the resin of the prepreg 25 is not easily penetrated into the four-axis woven fabric having a three-dimensional structure. The resin content of the prepreg 25 that is the counterpart is made larger than the resin content of other prepregs. The resin content is 30% or more, preferably 33% or more. The four-axis woven fabric 24 thus bonded together with the prepreg 25 constituting the second straight layer is wound around the surface of the first straight layer to form a four-axis woven fabric layer and a second straight layer.

  After forming the four-axis fabric layer and the second straight layer, after winding one prepreg 26, which is a sixth wound sheet in which the reinforcing fibers of the fiber-reinforced resin layer are substantially oriented in the shaft axis direction, A prepreg 27 which is a seventh winding sheet cut into a right triangle shape is wound around the tip end side of the shaft to form an outer diameter adjusting layer. After forming this outer diameter adjusting layer, it is wound and fixed with a polypropylene tape, and heat-cured in a heating furnace (not shown) to produce a golf club shaft composed of a plurality of fiber reinforced resin layers. The winding order of the outer diameter adjusting layer and the tip reinforcing layer does not have to be the order shown in FIG. 1, and can be arbitrarily determined according to the performance of the club. Further, the outer diameter adjusting layer made of a straight layer and the tip reinforcing layer are wound around the head side end portion of the shaft, but this step can be omitted, or two or more layers between a plurality of prepreg layers to be wound. You can also intervene.

  According to the illustrated example, the number of straight layers is three, but the number of layers is arbitrary, and is determined as appropriate according to the required performance as a golf club. In the present embodiment, the four-axis fabric 24 is interposed between the first and second straight layers. However, the position of the four-axis fabric 24 is arbitrary, and the three-dimensional structure of the four-axis fabric 24 is provided. In the case where importance is attached to the design properties depending on the prepreg, it is preferable to arrange a prepreg capable of seeing through the inside in the outermost layer and arrange the four-axis woven fabric 24 in the inner layer as described later.

As the matrix resin constituting the prepreg used in the method for manufacturing a golf club shaft of the present invention, a thermoplastic resin or a thermosetting resin can be used, but a thermosetting resin is preferably used.
As the thermoplastic resin, polyamide resins, polyacrylate resins, polystyrene resins, polyethylene resins, and mixed resins thereof can be used. On the other hand, as thermosetting resins, epoxy resins, unsaturated polyester resins, phenol resins, urea resins, melamine resins, diallyl phthalate resins, urethane resins, polyimide resins, and mixed resins thereof are used. Can be used. Among these, epoxy resins are most preferably used because they have a low cure shrinkage and high rigidity and toughness.

The fibers constituting the fiber reinforced resin layer used in the method for manufacturing a golf club shaft of the present invention include inorganic fibers such as metal fibers, boron fibers, carbon fibers, glass fibers, and ceramic fibers, aramid fibers, and other high fibers. A strong synthetic fiber or the like can be used. Inorganic fibers are preferably used because of their light weight and high strength. Among these, carbon fiber is optimal because it is excellent in specific strength and specific rigidity. Furthermore, when emphasizing the design, it is preferable to use glass fibers in consideration of the subsequent polishing treatment for the outermost layer.
These fibers can be used alone or in combination. Further, the length of the fibers such as long fibers, short fibers, and mixed fibers thereof is not particularly specified. However, the fibers constituting the four-axis fabric 24 are preferably long fibers.

  Usually, in a method for producing a golf club shaft composed of a fiber reinforced resin layer, the length is adjusted by cutting the small diameter end and the large diameter end after heat curing. The length after this cut is set to be the target length. For example, as shown in FIG. 1, when trying to obtain a golf club shaft having a total length of 1,165 mm, when cutting a small diameter end part by 11 mm and cutting a large diameter end part by 11 mm, the molding shaft length is set to Set to 1,143 mm.

  The material of the mandrel 10 is not particularly limited as long as it is made of metal, but is preferably made of iron from the viewpoint of easy processing such as taper and excellent durability. As shown in FIG. 1, the prepregs 21 to 23, 25 to 27, and the four-axis fabric 24 are wound around the mandrel 10. However, when the fiber reinforced resin layer is removed from the mandrel 10 after heat curing, demolding is easy. It is preferable to apply a release agent to the mandrel 10 in advance.

  In the golf club shaft manufacturing method of the present invention, first, a bias layer comprising a prepreg 21 in which reinforcing fibers of a fiber reinforced resin layer are oriented in a direction of ± 30 ° to ± 60 ° with respect to the shaft axial direction is provided on the mandrel 10. Wrap. The reinforcing fiber used for the prepreg 21 is optimal because the carbon fiber is excellent in specific strength and specific rigidity. Here, the bias layer constituting the first layer is substantially composed of two layers, and these two layers are pasted in advance by shifting substantially half a circumference in the circumferential direction of the shaft. For example, when the outer periphery of the small-diameter end of the shaft is 20 mm and the outer periphery of the large-diameter end is 40 mm, the prepreg 27 is shifted from the prepreg 26 with respect to the small-diameter end of the shaft. It means 10 mm and the large diameter end side is pasted by 20 mm.

  In order to partially strengthen the golf club shaft and improve the rigidity, a tip reinforcing layer having the shape shown in the second winding sheet in FIG. 1 can be wound next to the bias layer. May be. The reinforcing reinforcing fiber used in this reinforcing layer is also optimal because carbon fiber is excellent in specific strength and specific rigidity.

  Next, the first straight layer made of the prepreg 23 in which the reinforcing fibers of the fiber reinforced resin layer are substantially oriented in the shaft axial direction is wound. The 4-axis fabric 24 is wound around the surface of the first straight layer.

  Here, if the four-axis woven fabric 24 is to be handled alone, the woven fabric is too flexible, and the warp yarn 24a, the weft yarn 24b, and the diagonal yarns 24c, 24d are easily displaced from each other at each texture, and the texture is broken. The beauty of 4-axis fabric is lost. Therefore, in the illustrated example, before the four-axis fabric 24 is wound, the four-axis fabric 24 is attached in advance to the second straight layer made of the prepreg 25 as an upper layer. As a result, the four-axis woven fabric 24 is integrated with the second straight layer, and the woven form of the highly flexible one is stabilized and can be easily wound without breaking the weave. Here, although the 4-axis fabric 24 is affixed in advance to the second straight layer, it may be affixed in advance to the first straight layer. In addition, the winding position of the four-axis fabric 24 is not limited to the example illustrated in FIG. 1, and may be interposed between the second straight layer and the third straight layer, for example, and is not limited to the illustrated example. However, when the four-axis fabric 24 is attached to the prepreg, the resin content of the normal prepreg hardly impregnates the resin into the four-axis fabric 24 and the adhesive strength is weak. Therefore, in the present invention, the resin content of the prepreg to which the four-axis fabric 24 is attached in advance is set to 30% by weight or higher, which is higher than the normal resin content.

  The total number of fibers in one fiber bundle of reinforcing fibers used for the four-axis fabric 24 is preferably 1,000 to 12,000 filaments. If it is less than 1,000 filaments, the woven fabric structure becomes too small, and if it is more than 12,000 filaments, the woven fabric structure becomes too large and the design is impaired. The most preferable appearance of the golf club is 1,000 to 6,000 filaments.

Weight per unit area of the four-axis fabric, depending on the reinforcing fiber density used, reinforcing fiber is 30g / m ² ~250g / m ² in the case of carbon fibers, 10 g in the case the reinforcing fiber is an aramid fiber / M ^{2 to} 100 g / m ² is preferable.

When the reinforcing fiber is carbon fiber, if it is larger than 250 g / m ² , the bending of the reinforcing fiber forming the woven fabric and the reinforcing fiber of the straight layer wound around the outer layer of the four-axis woven fabric becomes large, and the smoothness of the shaft surface is only impaired. However, it is not preferable because the strength as the reinforcing fiber is lowered and the drape property after pre-adhering to the prepreg is also impaired. On the other hand, if it is less than 30 g / m ² , the gap of the woven fabric becomes large, and the reinforcing effect and design properties are impaired, which is not preferable.

  The fiber bundle of reinforcing fibers used is preferably composed of 1,000 to 12,000 filaments, and the width of the fiber bundle is preferably 1 mm to 5 mm. If it is smaller than 1 mm, it is not preferable because the void of the woven fabric becomes too large, and the smoothness reinforcing effect and design properties of the surface are impaired. If it is larger than 5 mm, the lattice-like pattern becomes too large and the design properties are inferior. . The most preferable appearance of the golf club is 1 mm to 3 mm.

  As the reinforcing fibers used in the four-axis fabric 24, inorganic fibers such as metal fibers, boron fibers, carbon fibers, glass fibers, and ceramic fibers, aramid fibers, and other high-strength synthetic fibers can be used. Inorganic fibers are preferably used because of their light weight and high strength. Among these, carbon fiber is optimal because it is excellent in specific strength and specific rigidity.

  The elastic modulus of the reinforcing fiber used for the four-axis fabric 24 is not particularly limited, but is preferably a carbon fiber of 240 GPa or more. If it is less than 240 GPa, sufficient rigidity as a golf club shaft cannot be obtained, and reinforcement is required, resulting in problems such as an increase in weight. If the elastic modulus of the reinforcing fiber is greater than 400 GPa, the tensile strength of the fiber is low, and the woven fabric itself has too high rigidity, so that the drapeability of the prepreg is impaired. It is preferable to set it as 400 GPa.

  In the illustrated example, a four-axis woven fabric 24 is used. However, this woven fabric is not limited to four axes, and may be, for example, three axes or six axes. Since the constituent yarns can be oriented in the shaft axial direction, the direction orthogonal to the axial direction, and the oblique direction to the axial direction, the bending and crushing rigidity of the shaft can be improved.

  In order to adjust the outer diameter of the small-diameter end of the golf club shaft, a reinforcing layer shaped like the second and seventh wrapping sheets in FIG. 1 may be wound first, in the middle, or last. These may be one or more. In addition, there is no restriction | limiting in the reinforcement fiber used for the prepreg of these reinforcement layers, However, Since carbon fiber is excellent in specific strength and specific rigidity, it is optimal.

  When emphasizing the design as a golf club, as described above, a prepreg made of glass fiber reinforced resin is wound around the outermost layer. The form of the glass fiber used for the prepreg in this case may be any of a woven fabric, a non-woven fabric, and a state aligned in one direction. As the matrix resin, a thermoplastic resin or a thermosetting resin can be used, but a thermosetting resin is preferably used, and an epoxy resin is particularly preferable because of its high properties such as adhesive strength and heat resistance and high transparency. It is.

  Although there is no restriction | limiting in particular about the thickness of the prepreg which consists of glass fiber reinforced resin of the outermost layer, The thickness of the glass fiber reinforced resin layer after winding needs to be 30 micrometers-100 micrometers. The shaft of a fiber reinforced resin golf club is polished to remove surface irregularities and adjust flex after heat molding. Therefore, when the thickness of the glass fiber reinforced resin layer after winding is smaller than 30 μm, the multiaxial fabric layer is polished together with the glass fiber reinforced resin layer at the time of polishing, or the unevenness of the multiaxial fabric layer remains and the surface smoothness is left. There are problems such as damage. Further, if the thickness of the glass fiber reinforced resin layer after winding is larger than 100 μm, the specific gravity of the glass fiber is heavy, and therefore there is a problem that the weight of the golf club shaft becomes heavy, which is not preferable. When the glass fiber reinforced resin layer is wound to have a thickness of 30 μm to 100 μm, these problems are solved, and a golf club shaft excellent in surface smoothness and design can be obtained.

  According to the method for manufacturing a golf club shaft according to the embodiment of the present invention described above, the multi-axis woven fabric has a high design and can be wound without yarn misalignment. In addition to improving the basic performance of the golf shaft, it is possible to manufacture a golf club shaft having excellent design characteristics without the need for complicated coating as in the prior art.

Next, the present invention will be described more specifically based on examples.
Table 1 shows the material (prepreg) of the golf club shaft produced in Examples 1 to 4 and Comparative Example 1. Moreover, the material of the 4-axis fabric used in Examples 1 to 4 and Comparative Example 1 is shown below.
<Materials used for 4-axis fabric>
Carbon fiber 4-axis fabric Fibers used (both longitudinal, lateral and diagonal): Carbon fiber tow (elastic modulus 240 GPa, 1,000 fibres)
Lament)
Number of drives: 8 vertical / inch
8 horizontal / inch
Diagonal 5.6 / inch
Thickness: 0.165mm
Weight: 73g / m ²
The materials used in the examples, the frequency of the golf club shaft, and the measurement of the twist angle are as follows.
(Materials used)
・ Prepreg

<Measurement of shaft frequency>
A 196 g weight imitating the head was mounted on the shaft for the golf club, and the position from the tip of the shaft on the large diameter side to 180 mm was fixed to a commercially available golf club vibration meter at an air pressure of 300 KPa. . The natural frequency of the golf club shaft was measured by applying vibration to the attached weight part by hand.

<Torsion angle>
The golf club shaft for wood is located from the shaft narrow end to 50 mm from the shaft narrow end, and from 1035 mm from the shaft narrow end to 1,067 mm from the shaft narrow end. The torsion angle when a torque of 138.5 kgf · mm was applied to the shaft was measured.
The materials shown in Table 2 were prepared for the wound prepreg sheets.

<Mandrel>
A mandrel 10 (made of iron) having the shape shown in FIG. 2 was prepared. The mandrel 10 has an overall length L3, the outer diameter of which gradually increases linearly from the narrow end P1 to the position (switching point) P2 of the length L1, and from the switching point P2 to the length L2. It consists of an iron cylinder whose outer diameter is constant up to the large diameter end P3. The specific outer diameter, length, and taper degree of each part of the mandrel 10 according to the present embodiment are as follows.

  The outer diameter of the small diameter end P1 is 5.00 mm, the outer diameter of the switching point P2 is 13.50 mm, the same outer diameter from the switching point P2 to the large diameter end P3, and the outer diameter is 13.50 mm. The length L1 from the small diameter end P1 to the switching point P2 is 1,000 mm, and the length L2 from the switching point P2 to the large diameter end P3 is 500 mm. The overall length L3 of the mandrel 10 is 1,500 mm. Further, the taper degree from the narrow end P1 to the switching point P2 is 8.50 / 1000.

<Cutting and winding of prepreg>
The 1st-7th winding sheet | seat was cut out to each prepreg (including 4 axis | shaft fabric) 21-27 shown in FIG.

  The first layer is formed by cutting the two prepregs 21 and 21 made of the first wrapping sheet into + 45 ° and −45 ° with respect to the longitudinal axis direction of the shaft, and shifting the prepregs 21 and 21 so that they substantially deviate from each other. A bias layer was formed by bonding using a fusing press. The size was adjusted as shown in FIG.

  The prepreg 22 cut out from the second wound sheet of the second layer has fibers oriented in the longitudinal axis direction of the shaft, and was adjusted to the size shown in FIG. 1 to obtain a tip reinforcing layer.

  The prepreg 23 cut out from the third wound sheet of the third layer has fibers oriented in the longitudinal axis direction of the shaft, has a total length of 1,165 mm, and is adjusted to the size shown in FIG. A straight layer was obtained.

  The fourth layer is a carbon fiber four-axis fabric 24 cut out of the fourth wound sheet, and the second axis is made of a prepreg 25 formed by cutting out the fifth wound sheet of the fifth layer. The straight layer was bonded using a fusing press to obtain fourth and fifth polymer layers of a four-axis fabric and a straight layer.

  The prepreg 26 obtained by cutting out the sixth wound sheet of the sixth layer has fibers oriented in the longitudinal direction of the shaft, and is adjusted to the size shown in FIG. 1 to form a sixth straight layer.

  In the prepreg 26 obtained by cutting the sixth wound sheet as the seventh layer, the fibers are oriented in the longitudinal axis direction of the shaft, and adjusted to the size shown in FIG.

  The prepregs (including a four-axis woven fabric) 21 to 27 cut into respective dimensional shapes were wound around the mandrel 10 in order. For winding, 100 mm from the small-diameter end of the mandrel was used as the winding end. The 4-axis fabric 24 was wound after being bonded to the prepreg 25 constituting the second straight layer. Winding at this time is easy, the portion where the prepreg at the small-diameter end of the shaft is bent greatly is not loose, the texture of the four-axis fabric 24 is not broken, and intersects the warp and weft yarns 24a, 24b and 90 °. The two diagonal threads 24c and 24d could be wound without any deviation.

  Subsequently, a heat-shrinkable polypropylene tape (not shown) having a thickness of 20 μm and a width of 30 mm was wound and fixed at a winding pitch of 2 mm to obtain a shaft base tube formed on the mandrel 10.

  The shaft base tube was put in a curing furnace and heated at 145 ° C. for 2 hours to cure the resin of the prepreg, and then the polypropylene tape and the mandrel 10 were removed. Both ends of the obtained golf club shaft base tube were cut by 11 mm to a total length of 1143 mm. Further, the obtained golf club shaft tube before polishing was polished with a polishing machine so that the outer diameter of the small diameter end was 8.5 mm and the shaft frequency was 245 cpm. Got the shaft. The golf club shaft after polishing had a weight of 53 g and a twist angle of 6 °.

  Further, when the shaft was cut at a position 100 mm from the small-diameter end and a position 100 mm from the large-diameter end of the golf club shaft, the cross-section was polished and observed at 100 times using an optical microscope. Some voids were observed in the shaft fabric layer.

Comparative Example 1

  The same prepreg and carbon fiber 4-axis woven fabric as in Example 1 were cut out with the same dimensions. The first straight layer was sequentially wound from the bias layer to the same position on the same mandrel as in Example 1. Furthermore, when trying to wrap the carbon fiber 4-axis fabric alone on the first straight layer, the direction of the fibers of the 4-axis fabric was disturbed and could not be wound well.

  The prepreg and carbon fiber 4-axis fabric shown in Table 2 were cut out with the dimensions shown in FIG. The second straight layer and the carbon fiber 4-axis woven fabric were bonded together in the same manner as in Example 1. Further, molding and polishing were performed in the same manner as in Example 1 to obtain a golf club shaft having a tip outer diameter of 8.5 mm, a vibration frequency of 245 cpm, a weight of 53 g, and a twist angle of 6.0 °.

  When the cross section of the obtained shaft was observed at the same position as in Example 1, slight voids were observed in the 4-axis fabric layer.

  The prepreg and carbon fiber 4-axis fabric shown in Table 2 were cut out with the dimensions shown in FIG. The second straight layer and the carbon fiber 4-axis woven fabric were bonded together in the same manner as in Example 1. Further, molding and polishing were performed in the same manner as in Example 1 to obtain a golf club shaft having a tip outer diameter of 8.5 mm, a vibration frequency of 245 cpm, a weight of 53 g, and a twist angle of 6.0 °.

  When the cross section of the obtained shaft was observed at the same position as in Example 1, no void was observed in the 4-axis fabric layer.

  The prepreg and carbon fiber 4-axis fabric shown in Table 2 were cut out with the dimensions shown in FIG. The protective layer, which is the seventh winding layer, and the carbon fiber 4-axis fabric were bonded together in the same manner as in Example 1. Further, molding and polishing were performed in the same manner as in Example 1 to obtain a golf club shaft having a tip outer diameter of 8.5 mm, a vibration frequency of 245 cpm, a weight of 53 g, and a twist angle of 6.0 °.

  When the cross section of the obtained shaft was observed at the same position as in Example 1, no void was found in the 4-axis fabric layer, and transparent clear coating was applied to the outer surface of the shaft. A golf club shaft with a high design property that can be recognized is obtained.

10 Mandrel 24 4-axis fabric (multi-axis fabric)
24a Warp 24b Weft
24c, 24d diagonal threads 21-23, 25-27 prepreg

Claims (4)

For a golf club made of fiber reinforced resin, comprising a layer formed by winding a reinforcing fiber prepreg in which a plurality of reinforcing fibers are aligned in one direction and impregnated with a resin, and a layer formed by winding one or more multiaxial fabrics A method of manufacturing a shaft,
A method for manufacturing a shaft for a golf club made of fiber reinforced resin, wherein a multiaxial woven fabric and a reinforced fiber prepreg are pre-bonded and integrated, and wound and molded on a mandrel.   The method for producing a fiber-reinforced resin golf club shaft according to claim 1, wherein the reinforcing fiber prepreg preliminarily bonded to the multiaxial fabric is a carbon fiber prepreg.   The method for producing a shaft for a fiber reinforced resin golf club according to claim 1, wherein the reinforcing fiber prepreg preliminarily bonded to the multiaxial fabric is a glass fiber prepreg, and the glass fiber prepreg is arranged in an outermost layer.   The method for producing a fiber-reinforced resin golf club shaft according to any one of claims 1 to 3, wherein the resin content of the reinforcing fiber prepreg preliminarily bonded to the multiaxial fabric is 30% by weight or more.

Images