JP2008173517A - Method for manufacturing golf club shaft - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for easily and inexpensively manufacturing a golf club shaft having appropriately high rigidity, producing a kick point at a suitable position, and convenient in use. <P>SOLUTION: According to this method for manufacturing a golf club shaft, fiber reinforced resin material is wound round a mandrel provided with a sloped part 16 increased in diameter toward one end part 14, and after the portion outside of the sloped part 15 is pressurized while a non-pressurizing area is provided in the sloped part 16, the non-pressurizing area is pressurized, and then heating/curing treatment is performed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a shaft of a golf club, and in particular, the rigidity of the hand portion is improved.

In golf clubs, weight reduction of the shaft is required to improve the head speed at the time of swing, but in addition, the feel at impact is improved by improving the bending rigidity of the hand portion. That is also required.
Therefore, Patent Documents 1 and 2 disclose a fiber reinforced resin shaft in which a member made of fiber reinforced resin is partially provided to adjust rigidity.
Further, Patent Document 3 describes a golf club shaft having an inclined portion having a diameter that increases toward the grip end, an inclination of 28/1000, a length of 254 mm, and an outer diameter of the grip end of 20.57 mm. In addition, there is described one having a quasi-inclined portion having an inclination gradient of 10.79 / 1000 on the tip side of the inclined portion.
Patent Document 4 includes a grip side taper portion, a head side small diameter portion, and an intermediate taper portion having a gradient of 2/1000 to 10/1000, a length of 200 to 600 mm, and a maximum outer diameter of 18 to 37 mm. A fiber reinforced resin golf club shaft is described.

However, in the golf club shafts in Patent Documents 1 and 2, since a separate member is provided, the manufacturing process becomes complicated, resulting in a significant increase in cost.
Further, Patent Document 5 discloses a fiber reinforced resin shaft in which a metal material layer is provided on a grip portion and rigidity is adjusted. However, even in this case, since the metal material layer is provided, the manufacturing process becomes complicated, accompanied by a significant increase in cost, and because the adhesion between the fiber reinforced resin and the metal is not high, the durability is low. Was expected.
Further, in the shaft described in Patent Document 3, since a straight portion having a length of about 150 mm is formed between the inclined portion and the quasi-inclined portion, the bending rigidity greatly changes in one shaft. There are two places on both ends of the straight portion. Therefore, the way the shaft bends differs depending on the golfer's swing speed and swinging method, which is inconvenient.
Further, in the shaft described in Patent Document 4, since a long equal-diameter portion is formed at the tip portion, the bending rigidity of the portion becomes low, the kick point becomes too high, and the usability is poor. .
Japanese Utility Model Publication No. 63-133261 Japanese Utility Model Publication No. 4-44968 US Pat. No. 3,614,101 Japanese Patent Laid-Open No. 9-299524 Utility Model Registration Gazette No. 2529041

  The present invention has been made in order to solve the above-mentioned problems, and has a reasonably high rigidity, a kick point is generated at an appropriate position, is easy to use, and can be easily and inexpensively manufactured as a golf club shaft. The purpose is to provide a manufacturing method.

The method for manufacturing a golf club shaft according to the present invention includes the step of winding a fiber reinforced resin material around a mandrel having an inclined portion having an enlarged diameter toward one end, and providing a non-pressurized region on the inclined portion, except for the inclined portion. After pressurizing, the non-pressurized region is pressurized, and thereafter, heating / curing treatment is performed.
In the method for manufacturing a golf club shaft of the present invention, a fiber reinforced resin material is applied to a mandrel having an inclined portion whose diameter is enlarged toward one end, and the fiber direction is 20 to 70 ° with respect to the longitudinal direction of the mandrel. An inner layer rolling step in which the mandrel is wound so as to have an angle, the mandrel is rotated on a rolling base of 30 to 40 ° C., and the fiber reinforced resin material is closely attached to the mandrel;
The fiber reinforced resin material is further wound on the mandrel around which the fiber reinforced resin material is wound so that the fiber direction is parallel to the longitudinal direction of the mandrel, and the mandrel is rotated on a rolling base at 20 to 25 ° C. An outer layer rolling step for closely adhering the fiber reinforcement;
It has a heating / curing treatment process for heating this,
In the inner layer rolling step and the outer layer rolling step, it is preferable to pressurize the non-pressurized region after pressurizing a portion other than the tilted portion while providing a non-pressurized region in the tilted portion.

In the method for manufacturing a golf club shaft of the present invention, a fiber reinforced resin material is wound around a mandrel formed with an inclined portion whose diameter is enlarged toward one end, and a portion other than the inclined portion is provided while providing a non-pressurized region on the inclined portion. Can be manufactured easily and reliably by a method through a manufacturing process in which the non-pressurized region is pressurized and then subjected to heating / curing treatment.
In addition, in the case of a golf club shaft having a multi-layer structure, a fiber reinforced resin material is applied to a mandrel having an inclined portion whose diameter is enlarged toward one end, and the fiber direction is 20 to 70 with respect to the longitudinal direction of the mandrel. An inner layer rolling step in which the fiber reinforced resin material is closely attached to the mandrel by rolling the mandrel on a rolling base at 30 to 40 ° C., and the mandrel wound around the fiber reinforced resin material. Further, an outer layer rolling step in which the fiber reinforced resin material is further wound so that the fiber direction thereof is parallel to the longitudinal direction of the mandrel, and the mandrel is rotated on a rolling base at 20 to 25 ° C. to closely adhere the fiber reinforcing material, A heating / curing treatment step for heating this, and in the inner layer rolling step and the outer layer rolling step, a non-pressurized region is not provided in the inclined portion. A portion other than the al inclined portion after pressurizing, the non-pressurizing rigid golf club shaft by the method through the manufacturing process of pressurizing the area can be easily and reliably manufactured.

  In addition, the golf club shaft obtained by the manufacturing method of the present invention is easy to manufacture with a small number of necessary parts, while being lightweight and moderately hard with high rigidity at the hand, and excellent in strength balance, and A kick point is generated at an appropriate position, and a good impression is obtained at the time of hitting. Further, since the outer diameter of the grip portion is increased, unnecessary movement of the wrist during the swing is suppressed, and the directionality of the hit ball is improved. In particular, when the length of the inclined portion is 200 to 350 mm and the outer diameter of the grip end is 18 to 25 mm, these performances are improved. Furthermore, since the quasi-inclined portion having an inclination gradient of 4/1000 to 13/1000 is formed on the tip side of the inclined portion, the rigidity can be appropriately increased. In addition, the golf club head can be easily attached by forming an equal-diameter portion having a length of 40 to 125 mm at the tip portion.

In the golf club shaft of the present invention, as shown in FIG. 1, the grip portion 12 is formed with an inclined portion 16 that expands toward the grip end portion 14, and the inclined portion 16 and the inclined portion 16 are larger than the inclined portion 16. A bent portion 20 in which the inclination gradient changes is formed between the tip 18 side and a quasi-inclined portion 19 is formed continuously.
In the present invention, the inclination of the inclined portion 16 is 15 to 35/1000. More preferably, it is 20-30 / 1000. In the present invention, since the inclined portion 16 is formed, the rigidity of the shaft is improved. When the inclined gradient is less than 15/1000, sufficient rigidity is difficult to obtain, and is larger than 35/1000. It becomes too hard and becomes unsuitable as a golf club shaft.
The length L of the inclined portion needs to be 200 to 350 mm. This is because if the length L is less than 200 mm, the effect of improving rigidity is small, and if it is longer than 350 mm, the golf club shaft becomes too hard. If it is 240-300 mm, it is more preferable.

Further, the end of the inclined portion on the diameter expansion side, that is, the grip end 14 needs to have an outer diameter of 18 to 25 mm. If it is thinner than 18 mm, the effect of improving the rigidity is small, and if it is thicker than 25 mm, it becomes too hard as a shaft for a golf club and it becomes difficult to grip. More preferably, it is 20-23 mm.
Further, it is necessary that a quasi-inclined portion 19 having an inclination gradient of 4/1000 to 13/1000 is formed on the tip side of the inclined portion 16. More preferably, the slope of the quasi-inclined portion 19 is 7 to 10/1000. If the slope is less than 4/1000, the rigidity of the quasi-slope part becomes extremely low, and the kick point becomes too high, which is not preferable as a golf club shaft. Further, if the slope is larger than 13/1000, the rigidity in the vicinity of the bent portion 20 becomes too high, which is not preferable as a golf club shaft.
Furthermore, the length of the quasi-inclined portion is desirably 50 to 80% with respect to the entire length of the shaft, and more preferably 60 to 75%. If it is less than 50%, an equal diameter portion is formed on the narrow diameter side or the large diameter side of the quasi-inclined portion, and when the equal diameter portion is formed on the small diameter side, the constant diameter portion is formed long at the tip portion. Therefore, the bending rigidity of the portion becomes low and the kick point becomes too high, which is not preferable as a shaft for a golf club. When formed on the large diameter side, there are many places where the bending rigidity greatly changes in the shaft. It tends to be a shaft that is hard to hit the ball. If it is longer than 80%, a sufficiently long inclined portion may not be formed.

Further, the kick point needs to be at a position of 40 to 46% from the narrow end with respect to the entire length of the shaft. It is more preferable if it is 41 to 45%. If it is less than 40%, the bending rigidity of the small diameter portion becomes too low and the strength is lowered. If it exceeds 46%, a ball with a high trajectory cannot be hit and a long flight distance is difficult to obtain.
In the golf club shaft of the present invention, it is desirable that an equal-diameter portion 22 having a constant thickness is formed at the tip portion to which the golf club head is attached. This is because the tip portion is inserted into the hosel portion of the golf club head to attach the golf club head. The attachment is performed by appropriately cutting the equal-diameter portion 22, so that the length S of the equal-diameter portion 22 is preferably 40 to 125 mm in order to cope with the processing.

As a material for the golf club shaft, a generally used material can be applied, and a material made of a metal material or a composite material is desirable.
Examples of the metal material include super tough steel, martensite steel, medium carbon 5% Cr steel, α + β type titanium alloy, β type titanium alloy and the like.
Examples of the composite material include fiber reinforcements such as various fiber reinforced metals and fiber reinforced resins.
Examples of the fiber of such a fiber reinforcing material include carbon fiber, glass fiber, aramid fiber, and inorganic fiber. Examples of the fiber form include unidirectional material, woven fabric, and non-woven fabric. Two or more kinds of union materials may be used.
Examples of the fiber reinforced metal matrix include aluminum and iron. Examples of the fiber reinforced resin matrix include unsaturated polyester resins, thermosetting resins such as vinyl ester resins and epoxy resins, and thermal resins such as acrylic resins and polyamide resins. A plastic resin is mentioned.
Among these fiber reinforcing materials, a carbon fiber reinforced epoxy resin material is preferable because it is lightweight and has high strength.

In addition, the shaft is not limited to a single layer structure, and in particular when a fiber reinforced resin material is used, it is desirable to have a multiple layer structure.
In the case of a multi-layer configuration made of a fiber reinforced resin material, the fiber direction of at least one of the layers is parallel to the longitudinal direction of the shaft, and the fiber direction of the other layers is 20 to 70 with respect to the longitudinal direction of the shaft. It is desirable to have an angle of °. Thus, the rigidity of the shaft at the time of a swing can be improved more by setting it as the shaft made from the fiber reinforced resin of the multi-layer structure from which the orientation direction of a fiber differs.

The golf club shaft manufacturing method of the present invention is the following method.
First, a mandrel having a predetermined shape and size in which an inclined portion whose diameter is enlarged toward one end is formed, a shaft material, for example, a fiber reinforced resin material cut into a predetermined dimension (for example, a fiber having a shape shown in FIG. 6). The reinforced resin material 38) is wound along and rolled on the rolling table to improve the tightening of the fiber reinforced resin material. The shape of the shaft is determined according to the outer shape of the mandrel, and in order to set the inclination of the inclined portion of the shaft to 15 to 35/1000, a mandrel having an inclined portion with an inclination of 10 to 40/1000 correspondingly is used. Use. Similarly, in order to set the inclination gradient of the quasi-inclined portion to 4 to 13/1000, a mandrel having an inclined portion having an inclination gradient of 4 to 16/1000 is used.
Then, after the glass cloth prepreg for preventing furnace dropping is wound around the grip portion, it is hung in the heating furnace to heat and cure the fiber reinforced resin material. Thereafter, the mandrel is extracted and polished and painted as necessary to produce a golf club shaft made of fiber reinforced resin.
Further, the outer diameter of the tip can be made equal by adjusting the number of layers or thickness of the fiber reinforced resin material wound around the mandrel. For example, by winding a triangular fiber reinforced resin material 40 as shown in FIG. 7 around the tip, the thickness can be made constant by increasing the number of layers along the tip.
A golf club is manufactured by attaching a golf club head and a grip to the obtained golf club shaft.

At this time, in the rolling process of rolling on the rolling table, in the golf club shaft having the bent portion of the present invention, an elastic receiving table 24 made of butyl rubber or the like is mounted on the rolling table 32 as shown in FIGS. The mandrel 30 is rotated while being pressed, and the mandrel 30 is pressed while rotating, pressurizing between the tip 18 and the bent portion 20 or in the vicinity of the bent portion 20 of the inclined portion 16, and applying a non-pressurized region 34 to the inclined portion 16 Next, as shown in FIGS. 2 and 4, the mandrel 30 is pressed against the elastic receiving bases 26 and 28 placed on the rolling base 32 while being rotated, and the inclined portion 16 and the bent portion 20 are pressed. It is desirable to apply an inclined portion pressurizing process that pressurizes the vicinity of the tip 18 and the vicinity of the tip 18 and pressurizes at least the non-pressurized region 34 that has not been subjected to the pressurizing process in the small diameter portion pressurizing process.
In this way, after pressurizing the portion other than the inclined portion first, the inclined portion is pressurized, so that the portion occupying a large proportion of the entire shaft is first firmly wound, and the strain generated at that time is inclined. The shaft having a bent portion can be manufactured by improving the overall tightening of the fiber reinforced resin material 36 while suppressing the generation of wrinkles.
3 is a side sectional view when the mandrel 30 is turned to the point A in FIG. 2, and FIG. 4 is a side sectional view when the mandrel 30 is turned to the point B in FIG.

Furthermore, when manufacturing a shaft made of fiber reinforced resin having at least two layers of an inner layer and an outer layer having different fiber orientation directions, first, as an inner layer rolling step, a fiber reinforced resin material is placed on a mandrel and the fiber direction is mandrel. The mandrel is wound on a rolling table at 30 to 40 ° C. so as to have an angle of 20 to 70 ° with respect to the longitudinal direction.
Next, as the outer layer rolling step, the fiber reinforced resin material is further wound around the mandrel wound with the fiber reinforced resin material in the inner layer forming step so that the fiber direction is parallel to the longitudinal direction of the mandrel, and the mandrel is 20 to 20 It is desirable to roll on a 25 ° C. rolling table.
Here, in the rolling process of the fiber reinforced resin material in which the fiber direction has an angle of 20 to 70 ° with respect to the longitudinal direction of the mandrel, a large resistance is generated due to the orientation direction. By setting it to -40 degreeC, a fiber reinforced resin material can be made more flexible, and it can make it easy to follow the shape of a mandrel. Further, in the rolling process of the fiber reinforced resin material in which the fiber direction is parallel to the longitudinal direction of the mandrel, the surface tack of the fiber reinforced resin material is reduced by setting the temperature of the rolling table to 20 to 25 ° C. Can be reduced, and the generation of voids can be suppressed.
As described above, the fiber reinforced resin material whose fiber direction is at an angle with respect to the longitudinal direction of the mandrel is used as the inner layer, and the fiber reinforced resin material whose fiber direction is parallel to the longitudinal direction of the mandrel is used as the outer layer. In addition, a fiber reinforced resin material whose fiber direction is parallel to the longitudinal direction of the mandrel can be used as an inner layer, and a fiber reinforced resin material whose fiber direction has an angle with respect to the longitudinal direction of the mandrel can be used as an outer layer. The bending rigidity of the shaft can be increased by using a fiber reinforced resin material parallel to the longitudinal direction of the mandrel as an outer layer.

The position of the kick point in the following examples etc. was measured as follows.
As shown in FIG. 10, the small-diameter end portion 44 is bent by applying a compressive force along the axial direction of the shaft 42 from the small-diameter end portion 44 and the large-diameter end portion 46 to the shaft 42 as a sample. When the length (x) in which the distance between the large-diameter end portion 46 is shortened becomes 20 mm, the mark (M) is marked at the most displaced position, and then the applied force is released and recovered. Then, the length (K) from the small diameter end portion 44 to the mark (M) was measured, and divided by the shaft length (N) to obtain a ratio, which was set as the position of the kick point.

[Example]
A golf club shaft was manufactured as follows.
For production, a mandrel having an inflection point having an outer diameter of 5.3 mm at one end (thin end) and an outer diameter of 21.5 mm at the other end (thick end) was used. Between the bending point and the thick end, the slope is 21/1000, and between the bending point and the narrow end, the slope is 10/1000.
After applying a mold release agent to this mandrel, a fiber reinforced resin material obtained by cutting a fiber reinforced resin (fiber basis weight: 125 g / m @ 2) impregnated with an epoxy resin into carbon fibers to a predetermined size, the fiber direction of the carbon fiber is mandrel. The laminates were wound around a mandrel so as to be + 45 ° and −45 ° with respect to the longitudinal direction.
Then, a glass fiber cloth prepreg for preventing furnace dropping was wound around the grip portion so as to protrude 30 mm from the mandrel.

And the fiber reinforced resin material was pressed on the mandrel using the rolling stand which set the surface temperature to 35 degreeC. At this time, as shown in FIGS. 2 and 3, the mandrel 30 is pressed against the elastic pedestal 24 made of butyl rubber placed on the rolling table 32 while rotating, and the tip 18 is provided with the non-pressurized region 34 provided on the inclined portion 16. Between the bent portion 20 and the vicinity of the bent portion 20 of the inclined portion 16 was pressed to improve the tightening of the fiber reinforced resin material 36.
Subsequently, as shown in FIGS. 2 and 4, the mandrel 30 is pressed against the elastic pedestals 26 and 28 made of butyl rubber placed on the rolling table 32 while rotating, and the inclined portion 16 including the non-pressurized region 34, The vicinity of the bent portion 20 and the vicinity of the tip 18 were pressurized to improve the tightening of the fiber reinforced resin material 36.
The elastic cradle 26 is a flat plate having a thickness of 3 mm, and the elastic cradles 24 and 28 are obtained by superposing two flat plates having a thickness of 3 mm. In FIG. 2, the lengths a = 250 and b = 200. C = 200, d = 250, e = 30, and f = 200 mm.

Next, a fiber reinforced resin material obtained by cutting a fiber reinforced resin (fiber basis weight: 150 g / m 2) obtained by impregnating an epoxy resin with a carbon fiber onto a mandrel around which the fiber reinforced resin material is wound to a predetermined size is used as the carbon fiber. Was wound so that the fiber direction was parallel to the longitudinal direction of the mandrel.
And using the rolling stand which set surface temperature to 22 degreeC, the fiber reinforced resin material was pressed on the mandrel similarly to the above.
Further, the triangular fiber reinforced resin material 40 shown in FIG. 7 was further wound around the tip portion so that the amount of wrapping increased with the tip, and the outer diameter of the tip portion was adjusted to be constant.
Furthermore, a polypropylene tape for maintaining the shape was wound on these at a pitch of 2.5 mm and hung in a heating furnace at 140 ° C. for 120 minutes to heat and cure the fiber reinforced resin material.
Thereafter, the polypropylene tape was peeled off, and the mandrel was extracted. Then, the golf club shaft having a two-layer structure made of carbon fiber reinforced resin was manufactured by performing necessary cutting and polishing treatments.

The obtained golf club shaft is as shown in FIG. 1, the total length (S + M + L) is 1145 mm, the length L of the inclined portion 16 is 245 mm, the length S of the equidiameter portion 22 is 75 mm, and it is bent from the tip 18. The length to the portion 20 (S + M) is 900 mm, the length m of the quasi-inclined portion 19 is 825 mm (72% with respect to the total shaft length), the outer diameter of the grip end 14 is 20 mm, and the slope of the inclined portion 16 is 21 / 1000, and the slope of the semi-inclined portion 19 was 10/1000. The kick point was 42% from the narrow end.
A golf club was manufactured by attaching a golf club head and a grip to the shaft.
When this golf club was used for trial hitting, a good evaluation with a very rigid feeling was obtained.

Further, for this golf club shaft, the rigidity value was determined for each distance from the tip (tip). The results are shown in FIG.
As is apparent from FIG. 5, it can be seen that the bending portion has a very high bending rigidity. A shaft for a golf club having such a rigidity distribution is very easy to use.

[Reference Example 1]
As a mandrel, the outer diameter of one end (thin end) is 4.6 mm, the outer diameter of the other end (thick end) is 13.5 mm, and the slope between the bending point and the thick end is 5/1000, and the bending point and the thin end are narrow. A golf club shaft was manufactured in the same manner as in the above-described example by using a slope with an inclination of 8/1000 between the ends.
The obtained golf club shaft has an outer diameter of the grip end 14 of 15.3 mm, a length of the inclined portion 16 of 265 mm, an inclination of the inclined portion 16 of 5/1000, and a length of the equal-diameter portion 22 of 75 mm. The inclination gradient in the quasi-inclined portion 19 was 8/1000. The kick point was 43% from the narrow end.
A golf club was manufactured by attaching a golf club head and a grip to a shaft having a small inclination of the inclined portion. When this golf club was used for a test shot, an unfavorable evaluation of a soft impression was obtained.

[Reference Example 2]
As a mandrel, the outer diameter at one end (narrow end) is 4.8 mm, the outer diameter at a position 700 mm from the narrow end is 6.2 mm, and the outer diameter at a position 234 mm (934 mm from the narrow end) is 21 A golf club shaft was manufactured in the same manner as in the above example, using a golf ball having an outer diameter of 22.8 mm at a position (thick end) of 400 mm from that position.
The obtained golf club shaft has an outer diameter of the grip end 14 of 25 mm, an outer diameter of 300 mm from the grip end 24 mm, and an outer diameter of 8.5 mm at a position 543 mm from the grip end. The outer diameter of the tip of the diameter is 8.5 mm, the slope gradient of the portion from the grip end to 300 mm toward the tip of the narrow diameter is 3.3 / 1000, and the diameter is 300 mm from the grip end. The slope gradient of the portion up to the position of 234 mm toward the distal end of the diameter was 63.8 / 1000, and the length of the equal diameter portion on the narrow distal end side was 600 mm. The kick point was 47% from the narrow end. The rigidity distribution of this shaft is shown in FIG.
A golf club was manufactured by attaching a golf club head and a grip to the shaft.
When this golf club was used for trial hitting, the grip portion had a small slope and the grip portion had a long outer diameter for a long time. Since the equal diameter portion is too long, the rigidity of the small diameter portion is low, the rigidity balance as a whole is poor, and the ball cannot be hit well at the time of hitting.

[Reference Example 3]
As a mandrel, the outer diameter at one end (narrow end) is 5.6 mm, the outer diameter at a position 775 mm from the narrow end is 13.9 mm, the outer diameter at a position 950 mm from the narrow end is 13.9 mm, and the outer diameter is 1250 mm from the narrow end A golf club shaft was manufactured in the same manner as in the above-described example, using a portion (thick end) having an outer diameter of 21.7 mm.
The obtained golf club shaft has an outer diameter of the grip end 14 of 21 mm, an outer diameter of 15 mm at a position of 235 mm from the grip end, an outer diameter of 15 mm at a position of 410 mm from the grip end, and a small-diameter tip. The outer diameter of the part is 8.5 mm, the slope gradient of the part between the grip end and the narrow end part to 235 mm is 25.5 / 1000, and the narrow end from the position of 235 mm from the grip end The portion with a constant diameter of up to 175 mm toward the portion is an equal diameter portion, and the slope gradient of the portion between the position of 410 mm from the grip end to 695 mm toward the small diameter end is 9.4 / 1000. The length of the equal diameter portion on the side was 40 mm. The kick point was 41% from the narrow end.
The rigidity distribution of this shaft is shown in FIG.
A golf club was manufactured by attaching a golf club head and a grip to the shaft.
When this golf club was used for trial hitting, it was evaluated that it was a club that was not easy to use because of its unstable ballistic trajectory because the degree of deflection of the shaft varied greatly depending on the amount of force during swing.

It is a side view which shows an example of the shaft for golf clubs manufactured with the manufacturing method of this invention. It is a top view which shows one process of the manufacturing method of the shaft for golf clubs of this invention. It is a sectional side view which shows one process of the manufacturing method of the shaft for golf clubs of this invention. It is a sectional side view which shows one process of the manufacturing method of the shaft for golf clubs of this invention. It is a graph which shows the intensity | strength change for every position in the shaft for golf clubs of a present Example. It is a top view which shows an example of a fiber reinforced resin material. It is a top view which shows an example of a fiber reinforced resin material. 5 is a graph showing the rigidity at each position in the golf club shaft of Reference Example 2. 10 is a graph showing the rigidity at each position in the golf club shaft of Reference Example 3. It is a side view for demonstrating the measuring method of a kick point.

Explanation of symbols

12 Grip part 14 Grip end part 16 Inclined part 18 Tip 19 Quasi-inclined part 20 Bent part 22 Equal diameter part 30 Mandrel 32 Rolling base 34 Non-pressurized area 36 Fiber reinforced resin material 38 Fiber reinforced resin material 40 Fiber reinforced resin material 42 Shaft 44 Small diameter end 46 Large diameter end

Claims (2)

  A fiber reinforced resin material is wrapped around a mandrel having an inclined portion whose diameter is expanded toward one end, and a portion other than the inclined portion is pressurized while providing a non-pressurized region on the inclined portion. A method for manufacturing a shaft for a golf club, characterized by applying pressure and then subjecting to heating and curing. It is a manufacturing method of the shaft for golf clubs of Claim 1, Comprising:
A fiber reinforced resin material is wound around a mandrel having an inclined portion whose diameter is expanded toward one end so that the fiber direction has an angle of 20 to 70 ° with respect to the longitudinal direction of the mandrel. An inner layer rolling process in which the fiber-reinforced resin material is closely attached to the mandrel by rolling on a rolling base at ℃;
The fiber reinforced resin material is further wound on the mandrel around which the fiber reinforced resin material is wound so that the fiber direction is parallel to the longitudinal direction of the mandrel, and the mandrel is rotated on a rolling base at 20 to 25 ° C. An outer layer rolling step for closely adhering the fiber reinforcement;
It has a heating / curing treatment process for heating this,
A golf club shaft characterized in that, during the inner layer rolling step and the outer layer rolling step, the non-pressurized region is pressurized after pressurizing a portion other than the inclined portion while providing a non-pressurized region in the inclined portion. Production method.

Images