JP3343485B2 - Golf club shaft and golf club manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a golf club shaft and a method for manufacturing a golf club .

[0002]

2. Description of the Related Art A golf club shaft of an over hosel type (hereinafter, simply referred to as a shaft) and a golf club head (hereinafter, also simply referred to as a head) are connected by connecting a shaft and a club to a hosel of the shaft. It is performed by inserting it into the inside of the unit and fixing it with an adhesive. In a golf club having an over hosel type shaft, as described above, since the connecting body that connects the shaft and the head is inserted inside the hosel portion of the shaft, at the moment of hitting the golf ball with the golf club, etc. Therefore, a large force is applied to the hosel portion of the shaft from the center to the outside. Therefore, it is important that the hosel portion of the shaft and the connector are firmly adhered to each other so as not to cause interfacial peeling even if the ball is repeatedly hit.
A torsional bond strength of kgf · cm or more is required. On the other hand, a fiber reinforced resin (FRP) shaft is formed by sequentially laminating a release agent layer, an adhesive layer, and a fiber reinforced thermosetting resin layer (thermosetting FRP layer) on the outer peripheral surface of a mandrel, and then heating. The thermosetting FRP layer is cured to form an FRP hollow tube, and then the mandrel is pulled out of the hollow tube. In the method of manufacturing the shaft, the release layer agent is required to pull out the mandrel from the hollow tube, and if the release agent layer is not provided, the mandrel can be smoothly pulled out from the hollow tube. Can not be done. Further, in the method for manufacturing the shaft, the adhesive layer is used for fixing the thermosetting FRP layer to the mandrel, and without this adhesive layer, the thermosetting FRP formed on the adhesive layer is used. It becomes difficult to form the layer easily and with good stability. In the method of manufacturing the shaft, after the mandrel is pulled out of the hollow tube, the adhesive layer and the release agent layer remain on the inner peripheral surface of the hollow tube. When the shaft thus obtained is used as an inner hosel type shaft in which the hosel portion is inserted into a pipe-shaped connection body attached to the club head, the outer peripheral surface of the hosel portion is a connection body. It is easy to adhere both firmly because it is adhered to the inner peripheral surface of the, but when used as an over hosel type shaft, the adhesive strength between the hosel part and the connecting body is a problem Become. That is, in this case, since the connector is inserted into the inside of the shaft and is bonded between the inner surface of the shaft and the outer surface of the connector, whether the release agent remains on the inner peripheral surface of the shaft, Even if the release agent does not remain, if the inner peripheral surface of the shaft is not formed on a rough surface, the adhesive strength becomes insufficient, and the head is displaced in the circumferential direction of the shaft upon repeated hitting, Problems such as the head falling off the shaft occur.

[0003]

SUMMARY OF THE INVENTION The present invention provides an over hosel type shaft which can be firmly adhered to a connecting member connecting the shaft and the head, a golf club having the shaft, and a method of manufacturing the same. Is the task.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have completed the present invention. That is, according to the present invention, after the fiber-reinforced thermosetting resin layer formed on the outer peripheral surface of the mandrel is thermoset to form a fiber-reinforced resin hollow tube, the step of removing the mandrel from the hollow tube In the method for manufacturing a golf club shaft comprising: (i) a rough surface imparting layer having a large number of irregularities on the resin layer side surface between the outer peripheral surface of at least the small diameter side tip portion of the mandrel and the resin layer. (Ii) removing the roughening layer from the hollow tube having a roughening layer on the inner circumferential surface after removing the mandrel, wherein the inner circumferential surface of the hosel portion is roughened. including a are formed on the surface
A method of manufacturing an over hosel type golf club shaft, characterized in that (ii) is performed after (i) . Further, according to the present invention, after the fiber-reinforced thermosetting resin layer formed on the outer peripheral surface of the mandrel is thermoset to form a fiber-reinforced resin hollow tube, a step of removing the mandrel from the hollow tube (I) a step of forming a release agent layer over the entire length of the outer peripheral surface of the mandrel, (ii) with respect to the outer peripheral surface of the mandrel on which the release agent layer is formed, Forming an adhesive layer over the entire length thereof, and (iii) forming a roughened surface providing layer having a large number of irregularities on the outer surface with respect to the outer peripheral surface of the tip portion on the small diameter side of the mandrel on which the adhesive layer has been formed. (Iv) a step of forming a second release agent layer on the roughening layer, (v) forming the release agent layer, the adhesive layer, the roughening layer and the second release agent layer A fiber-reinforced thermosetting resin layer is formed over the entire length of the outer surface of the mandrel (Vi) heat curing the resin layer to form a fiber reinforced resin hollow tube, (vii) removing a mandrel from the hollow tube, (viii) removing the mandrel Removing, from the hollow tube, the rough surface imparting layer and the second release agent layer present on the inner peripheral surface of the tip portion on the smaller diameter side in this order, the inner peripheral surface of the hosel portion is roughened. The present invention provides a method for manufacturing an over hosel type golf club shaft. Furthermore, according to the present invention, after the fiber-reinforced thermosetting resin layer formed on the outer peripheral surface of the mandrel is heat-cured to form a fiber-reinforced resin hollow tube, the step of removing the mandrel from the hollow tube (I) a step of forming a release agent layer over the entire length of the outer peripheral surface of the mandrel, (ii) with respect to the outer peripheral surface of the mandrel on which the release agent layer is formed, A step of forming an adhesive layer over the entire length thereof, (iii) a hardly-adhesive roughening layer having a large number of irregularities on an outer surface thereof with respect to an outer peripheral surface of a tip portion on a small diameter side of the mandrel on which the adhesive layer is formed. (Iv) forming a fiber-reinforced thermosetting resin layer over the entire length of the outer peripheral surface of the mandrel on which the release agent layer, the adhesive layer, and the roughening layer are formed; The resin layer is cured by heat and the fiber reinforced resin hollow tube Forming; (vi) removing the mandrel from the hollow tube; (vii) from the hollow tube from which the mandrel has been removed, a rough surface imparting layer present on the inner peripheral surface of the tip portion on the small diameter side thereof Are performed in this order, and a method of manufacturing an over-hosel type golf club shaft having a rough inner surface of a hosel portion is provided. Furthermore, according to the present invention, after the fiber-reinforced thermosetting resin layer formed on the outer peripheral surface of the mandrel is thermoset to form a fiber-reinforced resin hollow tube, the mandrel is removed from the hollow tube. A method of manufacturing a golf club shaft including the steps of: (i) forming a release agent layer on the outer peripheral surface of the mandrel over the entire length thereof; (ii) forming a release agent layer on the outer peripheral surface of the mandrel on which the release agent layer is formed. Forming an adhesive layer on the portion excluding the small-diameter tip portion, (iii) forming an adhesive layer on the outer peripheral surface of the small-diameter tip portion of the mandrel on which the adhesive layer has been formed, and further thereon. A step of forming a roughening layer made of a release film having a large number of irregularities on the surface thereof, (iv) the release agent layer, the adhesive layer and the outer peripheral surface of the mandrel on which the roughening layer is formed. Form a fiber-reinforced thermosetting resin layer over its entire length (V) thermally curing the resin layer to form a fiber-reinforced resin hollow tube, (vi) removing a mandrel from the hollow tube, (vii) after removing the mandrel Removing the rough surface-imparting layer present on the inner peripheral surface of the small-diameter end portion from the hollow tube in this order, wherein the inner peripheral surface of the hosel portion is formed in a rough surface. A method of manufacturing a golf club shaft of the type is provided. Still further, according to the present invention, a connecting body for connecting a golf club shaft and a golf club head is inserted into the tip side end portion of the shaft, and the shaft is used for bonding and fixing via an adhesive. A method for manufacturing a golf club, comprising using a golf club shaft obtained by any one of the above-described methods.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The shaft of the present invention is an over hosel type shaft, wherein at least the inner peripheral surface of the hosel portion of the shaft is formed as a rough surface. FIG. 1 is an explanatory cross-sectional view of an example of an FRP hollow tube formed on an outer peripheral surface of a small-diameter end portion (a mandrel portion including a hosel portion of a shaft) of a mandrel. In FIG. 1, 1 indicates the outer peripheral surface of the mandrel, 2 indicates a release agent layer formed thereon, 3 indicates an adhesive layer formed thereon, and 4 indicates a formed thereon. 5 shows a roughening layer and FRP formed thereon.
Show layers. The release agent layer 2 is a layer for facilitating removal of the mandrel when pulling out and removing the mandrel from the FRP hollow tube. The release agent layer 2 can be formed using a conventionally known release agent, for example, a wax-based or silicon-based release agent. The thickness of the release agent layer 2 is usually 1
To 30 μm, preferably 3 to 10 μm. The adhesive layer 3 is a layer that allows the rough surface imparting layer 4 formed thereon to be easily and stably formed on the outer peripheral surface of the mandrel. Since the release agent layer 2 has a large slip property, it is not easy to directly form the roughening layer 4 thereon.
When the adhesive layer 3 is provided, the surface of the adhesive layer has a low slip property, and the formation of the roughened layer 4 is facilitated. The adhesive layer can be formed using, for example, a phenol-based adhesive. The thickness of the adhesive layer is usually 3 to 100 μm, preferably 5 to 3 μm.
0 μm. The adhesive layer 3 can be formed by applying a liquid adhesive on the surface of the release agent layer 2 and drying it. When a release film is used as the roughening layer, the film may be formed in advance. The film can be formed by winding the film so that the adhesive layer thereof comes into contact with the release agent layer 2. In this case, the adhesive layer formed on the film surface needs to be maintained in a semi-solid state having adhesiveness or tackiness.

The rough surface imparting layer 4 is a layer formed on a rough surface having a large number of irregularities on its outer surface (FRP layer side surface), and is provided on the inner surface of the FRP layer 5 on its upper surface. It is used to form irregularities corresponding to a number of irregularities formed on the outer surface of the layer. That is, by pressurizing and thermosetting the thermosetting FRP layer on the roughening layer 4, a large number of irregularities are formed on the inner peripheral surface of the FRP layer (the contact surface with the roughening layer). Thus, it is possible to obtain an FRP hollow tube having a rough inner peripheral surface. Roughening layer 4
Has at least a surface layer thereof made of a poorly-adhesive material (a releasable material) and is weakly and releasably adhered to the FRP layer 5. Examples of the poorly-adhesive material include fluorine-containing resins such as polytetrafluoroethylene, polyvinylidene fluoride, and tetrafluoroethylene / olefin copolymer, as well as polyethylene terephthalate resin, polyimide resin, and polyphenylene sulfide resin. The roughening layer 4 is formed of a roughened film, a nonwoven fabric, a woven fabric,
It can be composed of a knitted cloth or the like. The thickness of the rough surface imparting layer 4 is not particularly limited, but is usually 5 to 100 μm, preferably 8 to 50 μm.

The FRP layer 5 is made of a thermosetting material of a fiber-reinforced thermosetting resin, and forms an FRP hollow tube. The thickness of the FRP layer 5 is not particularly limited, but is usually 1 to 9 mm,
Preferably it is 1.5 to 8 mm. In the fiber-reinforced thermosetting resin that provides the FRP layer 5, as the fiber, various fibers such as glass fiber, carbon fiber, Kevlar fiber, boron fiber, metal fiber, and ceramic fiber, and combinations of these fibers are used. Preferably, carbon fibers are used. Further, as the thermosetting resin, any one can be used as long as it gives a cured product having high mechanical strength, but preferably, a thermosetting epoxy resin composition mainly composed of an epoxy resin is used. Is used.

In a FRP hollow tube having a laminated structure shown in FIG. 1 having a cross-sectional structure of a hollow tube formed on the outer peripheral surface of the distal end portion on the small diameter side of the mandrel, the mandrel outer peripheral surface 1 is separated from the mold. The adhesive strength with the agent layer 2 is the smallest. Therefore, when pulling out the mandrel from the FRP hollow tube having such a laminated structure, separation occurs between the outer peripheral surface 1 of the mandrel and the release agent layer 2, and the release agent layer 2 adheres to the inner peripheral surface. Having agent layer 3 and roughening layer 4
The hollow tube 5 made is obtained. In this hollow tube 5, the F
As described above, since the RP layer 5 and the rough surface-imparting layer 4 are weakly adhered so that they can be peeled off, the outer surface of the FRP layer 5 is pulled by pulling the rough surface-imparting layer 4 to the outside. In addition, the roughening layer 4 can be peeled and removed together with the adhesive layer 3 and the release agent layer 2. In this way, an FRP hollow tube as a shaft raw tube is obtained.

In the FRP hollow tube having the structure shown in FIG. 1, when at least the outer peripheral surface of the mandrel is made of a release material such as a fluorine-containing resin,
The release agent layer 2 can be omitted.

Next, a method of manufacturing the over hosel type shaft of the present invention will be described in detail. First, the outer surface of the mandrel is applied to the release agent layer (first
(Release agent layer). This release agent layer can be formed according to a conventionally known method. In this case, for example, a wax-based or silicon-based release agent is used. The thickness of the release agent layer is 1 to 30 μm.
m, preferably 3 to 10 μm. Next, an adhesive layer is formed on the entire outer peripheral surface of the mandrel on which the release agent is formed. The formation of the adhesive can be performed according to a conventionally known method. In this case, examples of the adhesive include a phenol resin, an epoxy resin, a phenol resin prepreg, and an epoxy resin prepreg. The thickness of the adhesive layer is 3 to 100 μm, preferably 5 to 30 μm.

Next, a roughening layer is formed on the adhesive layer. The roughening layer may be formed over the entire length of the mandrel, but is preferably formed at the small diameter tip of the mandrel. In this case, the small-diameter tip portion of the mandrel is a portion corresponding to the hosel portion of the shaft or a portion including the hosel portion of the shaft, and is usually directed from the small-diameter tip of the mandrel to the large-diameter tip of the mandrel. The distance is about 1 to 20 cm, preferably about 2 to 10 cm. The roughening layer is a layer having a large number of irregularities on its outer surface (FRP layer side surface), and is used for bonding a roughened resin film, abrasive paper, abrasive cloth, nonwoven fabric, woven fabric, knitted fabric, etc. It can be formed by winding on the agent layer. Also,
This roughening layer can also be formed by applying a paint containing a large amount of solid particles. Examples of the resin film having a roughened outer surface include a resin film in which a large amount of solid particles are contained to make the surface uneven, a resin film in which the surface is sandblasted, a film in which the surface is embossed, and a surface in which the surface is chemically treated. Examples thereof include a resin film etched with a chemical, a resin film having a coating film containing a large amount of solid particles formed on the surface. In this case, as the resin film, a heat-resistant film that does not melt at a curing temperature at the time of curing the subsequent thermosetting FRP layer, for example, a fluororesin film, polyester, polyamide, polypropylene, etc. A film obtained by thermosetting a curable resin film can be used. The thickness of the roughening layer is not particularly limited, but is usually 5 to 100 μm, preferably 8 to 50 μm.

Next, a release agent layer (second release agent layer) is formed on the roughening layer. The formation of the second release agent layer can be performed in the same manner as the formation of the first release agent layer. The thickness of the second release agent layer is 1 to 30 μm, preferably 3 to 10 μm.

Next, after the formation of the second release agent layer, a thermosetting FRP layer is formed over the entire length of the mandrel.
The thermosetting FRP layer can be formed by a conventionally known method. For example, this layer can be formed by a filament winding method or a sheet winding method. Filament winding method (FW method)
Is a method of winding a filament impregnated with a thermosetting resin composition on a mandrel, and the sheet winding method (SW method) is a method of impregnating and semi-curing a prepreg formed by impregnating a thermosetting resin composition. This is a method of winding on a mandrel. The thickness of the thermosetting FRP layer is not particularly limited, but is usually about 1 to 9 mm, preferably about 1.5 to 8 mm.

After the formation of the thermosetting FRP layer, the mandrel on which the thermosetting FRP layer has been formed is heated in a heating furnace to cure the thermosetting FRP layer by a conventional method. In this case, prior to the heating, the thermosetting FR
In order to stably fix the P layer on the mandrel and efficiently cure the thermosetting FRP layer, it is preferable to tape a heat-resistant resin film on the layer. By curing the thermosetting FRP layer, an FRP hollow tube is formed on the outer peripheral surface of the mandrel. By pulling out the mandrel from this hollow tube, the FRP hollow tube from which the mandrel has been removed is formed. Get. The thus obtained FRP hollow tube has a first release agent layer on its inner peripheral surface,
It has an adhesive layer, a roughening layer and a second release agent layer. Next, after removing this rough surface providing layer together with the first release agent layer and the adhesive layer, the second release agent layer remaining on the inner peripheral surface of the hollow tube is removed, and an FRP hollow as a shaft tube is removed. Get the tube. In the hollow tube made of FRP, the inner peripheral surface of the portion corresponding to the hosel portion is formed with a rough surface corresponding to the outer shape of the roughened layer. When the roughening layer is a film, the roughening layer can be removed by pulling the film to the outside of the hollow tube. Moreover, it can also be performed by a physical method or a chemical method. As a physical method, there is a method of performing frictional force using a brush or the like, and as a chemical method, there is a method of dissolving and swelling and removing using an organic solvent or the like. The removal of the second release agent layer can also be performed by the physical method or the chemical method.

When a roughening layer is formed on a mandrel, the roughening layer may be formed of FR formed after heating.
It is preferably a hard-to-adhesive layer (release layer) that is weakly and releasably adhered to the inner peripheral surface of the P hollow tube. Such a poorly-adhesive rough surface-imparting layer can be formed using a film of which at least the surface layer is made of the following hardly-adhesive polymer material. (1) Fluorine-containing resin such as polytetrafluoroethylene, polyvinylidene fluoride, tetrafluoroethylene / olefin copolymer, etc. (2) Polyethylene terephthalate resin (3) Polyimide resin (4) Polyphenylene sulfide resin (5) Methylpentene polymer

When the hardly-adhesive roughening layer is formed,
A hard-to-adhesive film (release film) having one surface formed on the pressure-sensitive adhesive surface and the other surface formed as a rough surface, and the pressure-sensitive adhesive surface is provided on a mandrel with a release agent It is preferable to form by winding so as to be in contact with the adhesive layer formed through the layer. By forming the hardly-adhesive roughening layer in this manner, the hardly-adhesive roughening layer can be easily and stably formed. Further, when forming the poorly-adhesive roughened layer in this manner, the adhesive layer on the lower surface of the roughened layer is omitted because the lower surface of the film is formed on the pressure-sensitive adhesive surface. Even if it is omitted, the hardly-adhesive film can be easily and stably wound on the release agent layer.

[0017] of the present invention, the at least the hosel
In a shaft having a rough surface formed by using a rough surface providing layer on the peripheral surface, the roughness of the rough surface is not particularly limited, but the center line average roughness according to JIS B 0601 is as follows.
0.2 μm or more is preferable , and 0.4 to 1 is more preferable.
00 μm, more preferably 0.8 to 50 μm.
The FRP hollow tube obtained as described above is cut into a predetermined length, and the outer surface is polished to form a shaft.

[0018] The shaft of the present invention is used as an over hosel type shaft. When this shaft is connected to the head, a connecting body for connecting the head and the shaft is inserted into the inside of the hosel portion of the shaft and bonded. Immobilize. In this case, the connecting body may be of a type in which one end thereof is integrally mounted on the head in advance, or a connecting body mounting hole (communication hole in the pipe) formed in the head.
And may be of a type that is bonded and fixed. In the case of a connecting body whose one end is integrally attached to the head in advance, an adhesive is applied to the outer peripheral surface of the connecting body, and inserted into the hosel portion of the shaft to be bonded and fixed. On the other hand, in the case of a connection body independent of the head, in which the connection body is not attached to the head in advance, an adhesive is applied to the outer peripheral surface of the connection body, and one end of the connection body is attached to the connection body mounting hole of the head. Is inserted by a predetermined depth (length) and fixed by bonding, and the remaining portion of the connected body is inserted into the hosel portion of the shaft to be fixed by bonding. The material of the connecting body may be a material having a large mechanical strength,
Metal, FRP, or the like is used. Further, the connecting body can be a rod, a hollow tube, or the like. It is preferable to use the connecting body having a rough outer surface. Also,
In the case of a head having no connecting body attached in advance and having only an insertion hole for the connecting body, it is preferable to roughen the inner peripheral surface of the insertion hole. As the adhesive for bonding and fixing the shaft and the connecting body, any adhesive can be used as long as it provides high adhesive strength, but a liquid epoxy resin adhesive is generally used. . This material gives a high adhesive strength by being interposed in a liquid state between the outer peripheral surface of the connecting body and the inner peripheral surface of the shaft and curing at room temperature or under heating. The shaft of the present invention in which the connecting body is inserted into the inner surface of the hosel portion and bonded using a liquid epoxy adhesive has a high bonding strength, and the torsional bonding strength reaches 300 kgf · cm or more.

[0019]

Next, the present invention will be described in more detail with reference to examples.

REFERENCE EXAMPLE 1 A wax based on the entire length of a mandrel having an outer diameter of 8.50 mm at the tip end on the tip side, an outer diameter of 12.5 mm at the tip end on the pad side (grip side) and a total length of 1450 mm, and a parallel tip end of 100 mm. After uniformly applying the release agent, a phenolic adhesive was uniformly applied over the entire mandrel. A carbon fiber impregnated with an epoxy resin is wound on the pretreated mandrel so as to obtain a fiber layer having a three-layer structure, and then heated and cured. Then, the mandrel is removed, and the FRP hollow tube is removed. Obtained. Further, the release agent layer and the adhesive layer were completely removed from the inner diameter side of the hollow tube over about 100 mm, and the inside was roughened by sandblasting so that the FRP layer was roughened. Further, the outer surface of the hollow tube was polished to a prescribed shape. In this manner, the FR whose inner surface on the small diameter side is roughened (center line average roughness: 20.0 μm)
A P hollow tube was obtained. A connecting body of a head having a connecting body for connecting the head and the shaft was inserted into the inside of the small-diameter end of the hollow tube, and was fixed by bonding with a cold-setting epoxy resin, and the torsional bond strength was measured to be 350 kgf · cm. Thus, an over hosel type shaft having an adhesive strength of 3 mm was obtained.

Example 1 A wax release agent was applied to the entire length of a mandrel having an outer diameter of 8.50 mm at the tip end on the tip side, an outer diameter of 12.5 mm at the tip end on the pad side, and a total length of 1450 mm, and a parallel tip end of 100 mm. After uniform application, a phenolic adhesive was uniformly applied over the entire mandrel. Approximately 80 mm in the longitudinal direction at the narrow end of the pretreated mandrel
A film of polyvinylidene fluoride having irregularities on the surface having a length of was attached on the circumference. The carbon fiber impregnated with the epoxy resin was wound thereon so as to obtain a fiber layer having a three-layer structure, and then heated and cured, and then the mandrel was removed to obtain a hollow FRP tube. Further, after removing the polyvinylidene fluoride film present on the inner surface at the tip portion on the small diameter side from the hollow tube, the outer surface of the hollow tube was polished. In this way, an FRP hollow tube with a roughened inner surface (center line average roughness: 3.0 μm) at the tip portion on the smaller diameter side was obtained. A connecting body of a head having a connecting body for connecting the head and the shaft was inserted into the inside of the small-diameter end of the hollow tube, and was fixed by bonding with a cold-setting epoxy resin, and the torsional bond strength was measured to be 350 kgf · cm. Thus, an over hosel type shaft having an adhesive strength of 3 mm was obtained.

Reference Example 2 A wax-based release agent was applied to the entire length of a mandrel having an outer diameter of 8.50 mm at the tip end on the tip side, an outer diameter of 12.5 mm at the tip end on the pad side, and a total length of 1450 mm, and a parallel tip end of 100 mm. After uniform application, a phenolic adhesive was uniformly applied over the entire mandrel. Approximately 100 m in the longitudinal direction at the narrow end of the pretreated mandrel
m with a mean particle size of 1 on the phenolic adhesive
A mixture of a 00 μm inorganic filler was further uniformly applied. 3 carbon fibers impregnated with epoxy resin
After winding so as to obtain a layered fiber layer, the fiber layer was heated and cured, and then the mandrel was removed to obtain an FRP hollow tube. Further, the tip portion on the small diameter side of the hollow tube is immersed in a strong alkaline solution for 2 hours, and a release agent layer present inside the hollow tube,
The adhesive layer and the adhesive + inorganic filler layer were removed and washed with water. Further, the outer surface of the hollow tube was polished to a prescribed shape. Thus, an FRP hollow tube in which the inner surface of the tip portion on the smaller diameter side was roughened (center line average roughness: 10.0 μm) was obtained. A connecting body of a head having a connecting body for connecting the head and the shaft was inserted into the inside of the small-diameter end of the hollow tube, and was fixed by bonding with a cold-setting epoxy resin, and the torsional bond strength was measured to be 350 kgf · cm. Thus, an over hosel type shaft having an adhesive strength of 3 mm was obtained.

COMPARATIVE EXAMPLE 1 A wax-based release agent was applied to the entire length of a mandrel having an outer diameter of 8.50 mm at the tip end on the tip side, an outer diameter of 12.5 mm at the tip end on the pad side, and a total length of 1450 mm, and a parallel tip end of 100 mm. After uniform application, a phenolic adhesive was uniformly applied over the entire mandrel. A carbon fiber impregnated with an epoxy resin is wound around the pretreated mandrel so as to obtain a three-layered fiber layer, and then heated and cured, and then the mandrel is removed. Obtained. Inside the small-diameter end of the hollow tube, a head connecting body having a connecting body for connecting the head and the shaft was inserted, and was adhesively fixed with a cold-setting epoxy resin.
The torsional bond strength was only about 50 kgf · cm, and the head was displaced from the shaft in the circumferential direction or the head fell off the shaft upon repeated hitting as a golf club.

In the over hosel type shaft of the present invention, the inner peripheral surface of the hosel portion of the shaft is previously mandrel.
The head and shaft are firmly fixed by inserting the connector attached to the head into the hosel part and bonding and fixing it, since the rough surface is formed by the roughening layer formed between the metal and the FRP layer. Give a bonded golf club. The torsional bond strength between the head and the shaft in the golf club thus obtained is usually 300 kgf.
・ It reaches more than cm. According to the method of manufacturing a shaft according to the present invention, it is possible to industrially manufacture a shaft in which the inner peripheral surface of the tip portion on the tip side is formed as a rough surface.

[Brief description of the drawings]

FIG. 1 is an explanatory cross-sectional view of an example of an FRP hollow tube formed on an outer peripheral surface of a small-diameter end portion of a mandrel.

[Explanation of symbols]

 1 outer peripheral surface of mandrel 2 release agent layer 3 adhesive layer 4 roughening layer 5 FRP layer

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) A63B 53/10

Claims (5)

(57) [Claims] 1. A golf comprising a step of thermally curing a fiber-reinforced thermosetting resin layer formed on an outer peripheral surface of a mandrel to form a fiber-reinforced resin hollow tube, and then removing the mandrel from the hollow tube. In the method for manufacturing a club shaft, (i) forming a roughened surface providing layer having a large number of irregularities on the resin layer side surface between the outer peripheral surface of at least the small diameter side tip portion of the mandrel and the resin layer. (Ii) removing the roughening layer from the hollow tube having the roughening layer on the inner peripheral surface after removing the mandrel, and performing (ii) after (i). A method of manufacturing an over hosel type golf club shaft, wherein an inner peripheral surface of a hosel portion is formed rough. 2. A golf method comprising the steps of: thermally curing a fiber-reinforced thermosetting resin layer formed on the outer peripheral surface of a mandrel to form a fiber-reinforced resin hollow tube; and removing the mandrel from the hollow tube. In the method of manufacturing a club shaft, (i) a step of forming a release agent layer over the entire length of the outer peripheral surface of the mandrel, (ii) a step of forming a release agent layer over the entire length of the outer peripheral surface of the mandrel on which the release agent layer is formed. A step of forming an adhesive layer, (iii) a step of forming a roughened surface imparting layer having a large number of irregularities on the outer surface with respect to the outer peripheral surface of the narrow end portion of the mandrel on which the adhesive layer is formed, (iv) A) forming a second release agent layer on the roughening layer; (v) outer periphery of the mandrel on which the release agent layer, the adhesive layer, the roughening layer and the second release agent layer are formed. A step of forming a fiber-reinforced thermosetting resin layer over the entire length of the surface, (vi) a step of thermally curing the resin layer to form a fiber-reinforced resin hollow tube, (vii) a step of removing a mandrel from the hollow tube, and (viii) a hollow tube after removing the mandrel. Removing the roughening layer and the second mold release agent layer present on the inner peripheral surface of the tip portion on the narrower diameter side in this order. Manufacturing method of an over hosel type golf club shaft. 3. A golf method comprising the steps of thermally curing a fiber-reinforced thermosetting resin layer formed on the outer peripheral surface of a mandrel to form a fiber-reinforced resin hollow tube, and then removing the mandrel from the hollow tube. In the method of manufacturing a club shaft, (i) a step of forming a release agent layer over the entire length of the outer peripheral surface of the mandrel, (ii) a step of forming a release agent layer over the entire length of the outer peripheral surface of the mandrel on which the release agent layer is formed. A step of forming an adhesive layer, and (iii) a step of forming a hardly-adhesive roughened layer having a large number of irregularities on the outer surface thereof with respect to the outer peripheral surface of the tip portion on the small diameter side of the mandrel on which the adhesive layer is formed. (Iv) a step of forming a fiber-reinforced thermosetting resin layer over the entire length of the outer peripheral surface of the mandrel on which the release agent layer, the adhesive layer and the roughening layer are formed, and (v) forming the resin layer. Thermosetting to form fiber reinforced resin hollow tube (Vi) removing the mandrel from the hollow tube, (vii) removing the rough surface-imparting layer present on the inner peripheral surface of the small-diameter end portion from the hollow tube after removing the mandrel. to process, the method of manufacturing a golf club shaft of the over hosel type hosel inner peripheral surface is formed on the rough surface, characterized in that it is carried out in the this order. 4. A golf comprising a step of thermally curing a fiber-reinforced thermosetting resin layer formed on an outer peripheral surface of a mandrel to form a fiber-reinforced resin hollow tube, and removing the mandrel from the hollow tube. In the method of manufacturing a club shaft, (i) a step of forming a release agent layer on the entire outer peripheral surface of the mandrel, and (ii) a smaller diameter side with respect to the outer peripheral surface of the mandrel on which the release agent layer is formed. Forming an adhesive layer on the portion excluding the tip portion, (iii) forming an adhesive layer on the outer peripheral surface of the small-diameter side tip portion of the mandrel on which the adhesive layer has been formed, and further thereon, on the surface Forming a roughening layer comprising a release film having a large number of irregularities, (iv) the release agent layer, the adhesive layer and the outer peripheral surface of the mandrel on which the roughening layer is formed, over the entire length thereof. Forming a fiber-reinforced thermosetting resin layer, (v) Heat curing the resin layer to form a fiber reinforced resin hollow tube, (vi) removing a mandrel from the hollow tube, and (vii) removing the mandrel from the hollow tube after removing the mandrel. A step of removing a rough surface imparting layer present on the inner peripheral surface of the radial end portion, in this order, manufacturing a golf club shaft of an over hosel type having an inner peripheral surface of a hosel part formed with a rough surface. Method. 5. A method for manufacturing a golf club, wherein a connecting member for connecting a golf club shaft and a golf club head is inserted into a tip end portion of the shaft and bonded and fixed via an adhesive. Claim 1
4. A method for manufacturing a golf club, comprising using a golf club shaft obtained from the method for manufacturing a golf club shaft according to any one of 4.