JP6996073B2 - Golf club shafts for tubular bodies and putters, and their manufacturing methods - Google Patents

Description

INDUSTRIAL APPLICABILITY The present invention can be used as a support member such as a stay of a rear-view mirror of an automobile or a motorcycle, or a reinforcing material such as a frame of a bicycle, and in particular, a tubular body that can be suitably used as a golf club shaft for putters. Regarding the manufacturing method.

Fiber reinforced resins, especially carbon fiber reinforced resins, are lightweight and have excellent strength properties, and therefore have been widely applied to structural members having various shapes such as automobiles, motorcycles, bicycles, and aircraft, and in particular, carbon. The tubular body made of fiber reinforced resin is widely used for sports and leisure applications such as golf club shafts and fishing rods. Especially for golf clubs such as woods and irons, the weight reduction of the golf club shaft used greatly contributes to the increase in swing speed, which contributes to the increase in the flight distance of the ball. The percentage of resin shafts used is very high.

On the other hand, among golf clubs, putters require more precise control over the target because the main purpose of their use is not to fly the ball far, but to put the ball in the cup. Therefore, as golf clubs suitable for each player, heads and golf club shafts of various shapes such as a large head with a shape called a mallet type and a long type with a long golf club shaft such as a belly putter. A putter composed of is being developed. For such putters, not only straight type but also golf club shafts such as bend type and double bend type that are partially bent are used. Therefore, golf club shafts for these putters have workability. Excellent steel golf club shafts are commonly used.

However, with the diversification of putter shapes, it is difficult to reduce the weight of conventional golf club shafts for steel putters due to their material, which further improves the operability of the putter and improves the length and balance of the putter. It is desired to apply a carbon fiber reinforced resin golf club shaft to a putter in order to make more flexible adjustments. However, it is difficult to obtain a locally bent shape such as a bend type or double bend type for a conventional golf club shaft for putter made of carbon fiber reinforced resin due to molding restrictions, so a putter with a straight type shaft is used. Was mostly applied.

Patent Document 1 and Patent Document 2 disclose a bent golf shaft for a putter, which is formed by bonding a bent tubular object formed of a fiber bundle made of a large number of single fibers with a thermosetting resin. There is. However, this manufacturing method is a golf club shaft molded by so-called filament winding, and although it is possible to mold a bent shape, it is not possible to sufficiently arrange fiber bundles in the longitudinal direction of the golf club shaft. Therefore, there is a problem that sufficient rigidity required for a golf club shaft for a putter cannot be obtained and sufficient weight reduction cannot be realized.

On the other hand, in Patent Document 3, a carbon fiber reinforced plastic golf club made of carbon fiber reinforced plastic capable of setting a swing balance close to that of a steel shaft by providing carbon fiber reinforced plastic layers in which carbon fibers are oriented in a predetermined direction in an inner layer and an outer layer. Shafts for putters are disclosed. However, although this shaft can obtain a shaft for golf club putters made of carbon fiber reinforced plastic equivalent to a conventional steel shaft, it is limited to a straight type golf club shaft, so a bend type golf club shaft is installed. It could not be applied to the putter head.

Japanese Unexamined Patent Publication No. 52-132933 Japanese Unexamined Patent Publication No. 54-16241 Japanese Unexamined Patent Publication No. 10-15130

The present invention has been made in view of such circumstances, and can be used as a support member such as a stay of a rear-view mirror of an automobile or a motorcycle, or a reinforcing material such as a frame of a bicycle, and in particular, as a golf club shaft for putters. It is an object of the present invention to provide a tubular body that can be suitably used and a method for producing the same.

As a result of diligent studies in view of the above problems, the present inventors have found that the above problems can be solved by the following inventions, and completed the present invention.

That is, the present invention has the following configuration.
The present invention has the following configurations.
[1] A tubular body having a laminated structure of a fiber-reinforced resin cured product layer, wherein the tubular body has a bent portion, and among the fiber-reinforced resin cured product layers in the longitudinal direction including the bent portion. In at least one layer, continuous fibers contained in the fiber-reinforced resin cured product layer are seamlessly arranged, and the fibers of the fiber-reinforced resin cured product layer are oriented at 80 ° to 100 ° with respect to the longitudinal direction. A tubular body in which the hoop layer is laminated on the outermost layer of the bent portion.
[2] The tubular body according to [1], wherein the fiber-reinforced resin cured product layer is a carbon fiber-reinforced resin layer.
[3] It is composed of the tubular body according to any one of [1] and [2], and is composed of a tip portion A and a main body portion B, and the tip portion A has the bent portion at at least one place. The main body B has a tapered or straight shape, and the main body B has a tapered or straight shape with substantially no bending in the longitudinal axis direction of the shaft, and the tip A and the main body have no joint. A golf club shaft for putters composed of part B.
[4] The golf club shaft for putter according to [3], wherein the hoop layer is arranged in a region corresponding to 200 mm from the head side end to the head side end of the shaft.
[ 5 ] When the angle of the bent portion of the tip portion A is θn (n is an integer), respectively.
135 ° ≤ θn <180 °
The golf club shaft for a putter according to [3] or [4] , which comprises the range of.

[ 6 ] A prepreg consisting of a layer whose fiber direction is oriented at +30 to +70 ° with respect to the longitudinal direction of the tubular body and a layer whose fiber direction is oriented at -30 to -70 ° is wound around a mandrel and then heat-cured. To obtain a bias layer, a prepreg that forms a straight layer in which the fiber direction is aligned in the longitudinal direction of the tubular body is wound on the bias layer, a winding step, and a tape is spirally wound on the bias layer. After wrapping in a shape, the mandrel is removed to obtain a wrapping material, a step of obtaining a wrapping material, a step of heating the wrapping material to locally bend it, and a step of bending it, and heat curing while maintaining the locally bent state. The winding step is a step of winding the prepreg forming the auxiliary layer, and the auxiliary layer has 80 fibers of the fiber -reinforced resin with respect to the longitudinal direction of the tubular body. A method for producing a tubular body which is a hoop layer oriented at ° to 100 ° and has a bent portion in which a continuous fiber-reinforced resin cured product layer is laminated to bend the bias layer in the bending step.
[ 7 ] The method for producing a tubular body according to [ 6 ], wherein in the step of obtaining the bias layer, the prepreg is wound so as to seamlessly arrange fibers continuous in the longitudinal direction including the bent portion of the tubular body. ..
[ 8 ] The method for producing a tubular body according to [ 6 ] or [ 7 ], wherein the fiber reinforced resin is a carbon fiber reinforced resin.
[ 9 ] In the bending step, when bending one or more places of the tubular body, when the bending angle of the tubular body is set to θn (n is an integer), respectively.
135 ° ≤ θn <180 °
The method for producing a tubular body according to any one of [ 6 ] to [ 8 ], which is within the range of.
[ 10 ] The method for producing a tubular body according to any one of [ 6 ] to [ 9 ], wherein the matrix resin used for the prepreg is an epoxy resin.

According to the tubular body according to the present invention, since it has a bent portion and is lightweight and has high rigidity, it should be used as a support member such as a stay of a rearview mirror of an automobile or a motorcycle, or as a reinforcing material such as a frame of a bicycle. In particular, it can be suitably used as a golf club shaft for putters.
Further, according to the method for manufacturing a tubular body according to the present invention, it is possible to impart a bent portion to a tubular body on which a fiber-reinforced resin cured product layer in which fibers are continuous in the longitudinal direction is laminated, which has been difficult in the past. This is particularly suitable as a method for manufacturing a golf club shaft for putters.

It is a schematic explanatory drawing of the mandrel used in Examples 1 and 2 and Comparative Example 1. It is explanatory drawing which shows the cut shape of the prepreg used for manufacturing the shaft for the golf club for a putter in Examples 1 and 2 and the winding order around a mandrel. It is explanatory drawing which shows the cut shape of the prepreg used for manufacturing the shaft for the golf club for a putter in the comparative example 1, and the winding order around a mandrel. It is the schematic explanatory drawing of the mandrel used in Examples 3-4 and Comparative Example 2. It is explanatory drawing which shows the cut shape of the prepreg used for manufacturing the shaft for the golf club for a putter in Examples 3-4, and the winding order around a mandrel. It is explanatory drawing which shows the cut shape of the prepreg used for manufacturing the shaft for the golf club for a putter in the comparative example 2, and the winding order around a mandrel.

The tubular body of the present invention has a laminated structure of a fiber-reinforced resin cured product layer having a bent portion, and continuous fibers in the longitudinal direction of the tubular body including the bent portion are seamlessly arranged. It is possible to reduce the weight while ensuring sufficient strength and rigidity.

The above-mentioned fibers arranged in the tubular body of the present invention are not particularly limited, and carbon fibers, glass fibers, aramid fibers, silicon carbide fibers, alumina fibers, steel fibers and the like can be appropriately selected and used. However, carbon fiber is particularly preferable because it can achieve both improvement in strength and rigidity and weight reduction.

Further, the shape of the tubular body of the present invention is not particularly limited, and a circular cross section, an elliptical shape, a triangular shape, a square shape, or the like can be appropriately selected, but a circular shape (cylindrical shape) is preferable from the viewpoint of strength. In particular, it can be suitably used as a golf shaft for putters.

Hereinafter, the tubular body of the present invention will be described by taking a golf club shaft for putter as an example.
The golf club shaft for putter, which is one of the embodiments of the tubular body of the present invention, is preferably made of carbon fiber reinforced resin, has a cylindrical shape, and has a straight shape or an outer diameter of a surface perpendicular to the axial direction. Has a tapered shape that increases from one end to the other end in the length direction, and includes, for example, one formed so that the outer diameters are the same from both ends to the diameter switching portion in the middle. Hereinafter, in the case of a tapered shape, the end portion on the side having a small outer diameter is referred to as a small diameter end portion, and the end portion on the side having a large outer diameter is referred to as a large diameter end portion. Further, the region from the small diameter end to the small diameter end to 200 mm is referred to as the tip portion A, the region from the small diameter end to 200 mm to the large diameter end is referred to as the main body portion B, and at least one tip portion A is locally bent. is doing.

In the above-mentioned golf club shaft for putter, the winding angle of the fiber with respect to the longitudinal direction of the tubular body is within the range of 30 to 70 °, and the bias layer having both forward and reverse directions and the winding angle of the fiber with respect to the longitudinal direction of the tubular body are -5 °. A golf club shaft for putters made of fiber-reinforced resin having a straight layer in the range of ~ + 5 °. In this golf club shaft for putter, a fiber reinforced resin layer (hereinafter, sometimes referred to as prepreg) in which a sheet-shaped reinforced fiber made by aligning the fibers in one direction is impregnated with a resin is used as a mandrel (core metal). It can be manufactured by a sheet wrapping method in which the fibers are wound a plurality of times, heated, cured, and molded.

A carbon fiber reinforced resin layer is preferably selected as the prepreg. As the carbon fibers used here, either PAN-based carbon fibers made from polyacrylonitrile fiber or pitch-based carbon fibers made from petroleum or coal pitch can be used, but they are bent. High-strength PAN-based carbon fiber is preferably used in order to sufficiently increase the strength of the portion. Further, glass fiber, aramid fiber, silicon carbide fiber, alumina fiber, steel fiber and the like may be used in combination with carbon fiber.

The matrix resin used for the above-mentioned prepreg is not particularly limited, but an epoxy resin is usually used. Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, glycidylamine type epoxy resin, isocyanate-modified epoxy resin or alicyclic type. Epoxy resin or the like can be used. These epoxy resins can be used from liquid to solid. Further, a single type of epoxy resin or two or more types of epoxy resins can be mixed and used.

In the putter golf club shaft of the present embodiment, for example, the region from the small diameter end to the small diameter end of the shaft to 200 mm is the tip portion A, and the region from the small diameter end to the large diameter end of the shaft is the main body portion B. The main body portion B has a tapered or straight cylindrical shape with substantially no bending in the longitudinal axis direction of the shaft, and the tip portion A has a tapered shape or a tapered shape in which at least one portion is locally bent. It has a straight cylindrical shape, and the tip portion A and the main body portion B are integrally molded with a prepreg without having a joint portion.

The tip portion A has a partially bent shape for adjusting a putter such as a face progression and a lie angle. By making the shape of the tip portion A the optimum shape for each putter, it is possible to manufacture a putter having excellent operability.

As described above, the golf club shaft for putters of the present embodiment is preferably made of a carbon fiber reinforced resin cured product layer. A prepreg in which reinforcing fibers are oriented at 30 ° to 70 ° with respect to the longitudinal direction of a golf club shaft for putter, a bias layer formed by laminating prepregs oriented at -30 ° to -70 °, and a length. It is preferable to have a straight layer formed from prepregs in which the reinforcing fibers are oriented at −5 ° to + 5 ° with respect to the direction. Further, it is important that the tip portion A and the main body portion B are integrally molded without being joined. If the tip portion A and the main body portion B are separately molded and joined, the structure becomes complicated and the weight becomes heavy at the joint portion, and sufficient strength cannot be obtained when the joint portion is joined with an adhesive or the like, which is not preferable. It is important that the golf club shaft for putters of the present embodiment is integrally molded with the tip portion A and the main body portion B with a prepreg.

The laminated structure of the tip A of the putter golf club shaft of the present embodiment is a hoop formed from a prepreg having reinforcing fibers oriented at 80 ° to 100 ° with respect to the longitudinal direction of the putter golf club shaft in the outermost layer. Having a layer is a more preferred form. The tip portion A needs to be bent locally, but if the straight layer or the bias layer is arranged in the outermost layer at that time, the reinforcing fibers in the outermost layer may be broken or bent. It may be difficult to secure sufficient strength due to the nature. On the other hand, by arranging a hoop layer composed of prepregs in which reinforcing fibers are oriented at 80 ° to 100 ° in the outermost layer, it is possible to suppress the occurrence of such a problem, and golf for putters having higher strength can be suppressed. It becomes possible to obtain a club shaft.

Further, in the tip portion A of the golf club shaft for putter of the present embodiment, the angle formed by the intersection of the axis of the shaft on the large diameter end side from the bent portion and the axis of the shaft on the small diameter end side from the bent portion is θn, respectively. When (n is an integer)
135 ° ≤ θn <180 °
It is preferably in the range of. This is because by setting this angle to 135 ° or more, the reinforcing fibers are less likely to break or the shaft is less likely to be crushed during shaft manufacturing, and the productivity of the shaft tends to be improved. More preferably
145 ° ≤ θn <180 °
Within this range, it is possible to sufficiently suppress a decrease in strength due to bending of the reinforcing fibers.

When the weight of the putter golf club shaft of the present embodiment is G (g) and the distance (mm) from the small diameter end to the large diameter end of the shaft is L,
0.03 ≤ G / L ≤ 0.15
It is preferably in the range of. When the G / L is smaller than 0.03, the amount of the cured fiber resin layer tends to be too small, so that the rigidity may not be sufficient or the strength may not be sufficient, and the G / L is 0. If it is larger than 15, the rigidity of the shaft becomes too high, which makes it difficult to manufacture the shaft, and the total weight of the putter becomes too heavy, which may impair operability. More preferably
0.04 ≤ G / L ≤ 0.13
Within this range, it is possible to achieve both sufficient rigidity and strength as a golf club shaft for putters and high operability.

The tubular body in which the continuous fiber-reinforced resin cured product layers of the present invention are laminated has a layer in which the fiber direction is oriented at +30 to +70 ° with respect to the longitudinal direction of the tubular body and a layer having a fiber direction of −30 to −70 °. A step of winding a prepreg consisting of a layer oriented in the direction of a mandrel and then heat-curing to obtain a bias layer, and a step of winding a prepreg forming a straight layer in which the fiber directions are aligned in the longitudinal direction of the tubular body. A process of spirally winding the tape from above and then removing the mandrel to obtain a wound object, a process of heating the wound object to locally bend it, and a process of heating and curing while maintaining the locally bent state. It can be manufactured by passing through.

This manufacturing method can be suitably adopted for manufacturing a tubular body made of the carbon fiber reinforced resin cured product layer described above, and is a method suitable for manufacturing a tubular body having the cylindrical shape described above, and the bent portion described above. It is particularly suitable as a method for manufacturing a golf club for putters having the above.

In the above method for producing a tubular body, first, a tubular fiber-reinforced resin cured product having a bias layer is formed as an inner layer of the tubular body. This makes it possible to suppress damage to the inner layer when the mandrel is removed later, and deformation and breakage of the tubular body when the tubular body is heated and locally bent.
This cured product preferably consists of only a bias layer, and is preferably formed as an innermost layer.

Further, in order to stabilize the shape of the cured product having the bias layer and make the curing of the entire cured product uniform, in the step of winding the prepreg around the mandrel and then heat-curing the prepreg, after winding the prepreg, from above. It is preferable to wind the tape in a spiral shape and then heat-cure it, and then remove the tape after heat-curing.
The tape used here can be appropriately selected depending on the type of the cured resin and the curing conditions. For example, when an epoxy resin having a curing temperature of 130 to 140 ° C. is used as the matrix resin of the fiber reinforced resin layer. A shrink film made of polypropylene having a width of 2 to 3 cm can be used.

In the above method for manufacturing a tubular body, a prepreg forming a straight layer in which fibers are aligned in the longitudinal direction of the tubular body is wound on a cured product of a tubular fiber reinforced resin having a bias layer.

Further, if necessary, a prepreg forming an auxiliary layer can also be wound.
As the auxiliary layer, the above-mentioned straight layer or bias layer can be adopted, but the above-mentioned hoop layer can be preferably adopted, and by providing this at the bent portion of the tubular body, the strength of this portion can be adopted. Can be improved. In particular, when this tubular body is used as a golf shaft for a putter, it is preferable to form the hoop layer in a region corresponding to 200 mm from the head side end to the head side end of the shaft.
After winding the prepreg forming the straight layer and the auxiliary layer described above, the same tape as described above is spirally wound on the prepreg forming the bias layer, and then the mandrel is removed to obtain a wound object.

The bent portion of the wound object is bent while being locally heated to obtain a desired shape. The heating temperature at this time is preferably in a range of a temperature equal to or higher than the temperature at which the uncured resin of the wound prepreg softens and a temperature lower than the temperature at which the resin starts to cure. In addition, it is preferable to bend as slowly as possible in order to avoid damage to the reinforcing fibers as much as possible.
In this bending step, a part of the bias layer that has already been cured may be damaged, but the effect of this on the physical properties of the finally obtained bent portion of the tubular body is practically negligible. Is.

The position of the bent portion can be appropriately selected depending on the intended use of the obtained tubular body, but when this tubular body is used for a golf shaft for a putter, it is 200 mm from the head side end to the head side end of the shaft. It is preferable to bend the region corresponding to.

The angle of the bent portion can be appropriately selected depending on the intended use of the obtained tubular body, but when this tubular body is used for a golf shaft for a putter, the head side end to the head side end of the shaft is used. When bending one or more of the regions corresponding to 200 mm from the ground, when the bending angle is θn (n is an integer), respectively.
135 ° ≤ θn <180 °
It is preferable that the range is within the range of.
This is because by setting this angle to 135 ° or more, the reinforcing fibers are less likely to break or the shaft is less likely to be crushed during shaft manufacturing, and the productivity of the shaft tends to be improved.
More preferably
145 ° ≤ θn <180 °
Within this range, it is possible to sufficiently suppress a decrease in strength due to bending of the reinforcing fibers.

After forming the bent portion at a specific portion as described above, the tubular body of the present invention can be obtained by heating at the curing temperature of the resin while maintaining the bent state. It is also preferable to use a mold or a fixing jig in order to maintain the bent state. By using a mold or a fixing jig, a more accurate bent tubular body can be obtained.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples.

(Example 1)
A mandrel 10 (made of iron) having the shape shown in FIG. 1 was prepared. The mandrel 10 has an overall length L13, and its outer diameter gradually increases linearly from the small diameter end P11 to the position (switching point) P12 of the length L11, and the length L12 from the switching point P12. It is made of an iron cylinder having a constant outer diameter up to the large diameter end P13. The specific outer diameter, length, and taper degree of each part of the mandrel 10 according to this embodiment are as follows.

The outer diameter of the small diameter end P11 is 3.85 mm, the outer diameter of the switching point P12 is 13.75 mm, and the outer diameter from the switching point P12 to the large diameter end P13 is the same, and the outer diameter is 13.75 mm. The length L11 from the small diameter end P11 to the switching point P12 is 900 mm, and the length L12 from the switching point P12 to the large diameter end P13 is 600 mm. The total length L13 of the mandrel 10 is 1500 mm. Further, the taper degree from the small diameter end P11 to the switching point P12 is 11.00 / 1000.

Of the prepregs (patterns 1 to 10) cut into the shape shown in FIG. 2, pattern 1 is wound around the mandrel 10, and a 20 mm wide polypropylene shrinkage tape is wound around the mandrel 10 at a pitch of 2 mm, and then heated and cured. I let you. In pattern 1, the prepreg in which the carbon fiber (CF) is oriented at + 45 ° with respect to the axial direction of the mandrel and the prepreg oriented at −45 ° are substantially offset by half with respect to the mandrel 10. It is a stack of two sheets.
The materials of the prepregs 1 to 6 in FIG. 2 are shown in Table 1, and the sizes of the prepreg parts of the patterns 1 to 10 are shown in Table 2.

The region around which the prepreg is wound in the mandrel 10 is from 225 mm as measured from the small diameter end of the mandrel to a position of 985 mm toward the large diameter end. Pattern 1 using prepreg 1 is wrapped around a mandrel 10, and a 20 mm wide polypropylene shrinkage tape is wrapped around it at a pitch of 2 mm. The cured shaft was removed from the mandrel 10 by allowing it to cool naturally until, and the shrinkage tape was peeled off.

Incidentally, in this pattern 1, the prepreg forming the bias layer in which the carbon fibers (CF) are oriented at + 45 ° with respect to the axial direction of the mandrel and the prepreg forming the bias layer oriented at −45 ° are thick. The diameter side end is shifted by 22 mm (y11) and the small diameter side end is shifted by 10 mm (x11), and the layers are overlapped.

After heat curing, the mandrel 10 was removed and the polypropylene shrinkage tape was peeled off to obtain a premolded shaft. Then, the pre-molded shaft is inserted into the mandrel 10 again, patterns 2 to 10 are wound around the pre-molded shaft in order, 20 mm wide polypropylene shrinkage tape is wound around the pre-molded shaft at a pitch of 2 mm, and then the mandrel 10 is wound again. I pulled it out. Pattern 10 corresponds to a hoop layer in which the winding angle of the reinforcing fiber with respect to the main shaft of the mandrel 10 is 90 °, and patterns 2 to 9 correspond to a straight layer in which the winding angle of the reinforcing fiber is 0 ° with respect to the main shaft of the mandrel 10. do.

The shaft was carefully bent so as to have a desired shape while being heated with a dryer on the tip portion A of the uncured shaft from which the mandrel 10 was extracted, and the shaft was heat-cured while being careful not to change the shape. If too much heat is applied when bending the shaft, the fluidity of the resin will increase and the curing reaction will start. Therefore, the work was carried out with careful attention to how to heat it. Then, after heat curing, the polypropylene shrinkage tape was peeled off, and then 10 mm from the small diameter end portion and 10 mm from the large diameter end portion were cut and polished so that the surface became smooth.

In the two prepregs of the pattern 1 in this embodiment, the winding angle of the reinforcing fibers with respect to the main axis of the mandrel 10 is 45 °, and a bias layer is formed in both forward and reverse directions, and the pattern 10 is with respect to the main axis of the mandrel 10. The reinforcing fibers form a hoop layer having a winding angle of 90 °, and patterns 2 to 9 form a straight layer having a winding angle of the reinforcing fibers of 0 ° with respect to the main axis of the mandrel 10.

Table 4 shows the mass G of the obtained shaft, the total length L, and the outer diameters at positions 10 mm from the small diameter end and 25 mm from the large diameter end. Further, in this embodiment, bending is performed at two points of 60 mm and 125 mm from the small diameter end portion, the respective angles are set to θ1 and θ2, and the respective values are shown in Table 4.

[Installation of golf club head and grip]
A commercially available putter head (mass 374 g) was attached to the small diameter end of the golf club shaft for putter of the example with an acrylic resin adhesive. Further, the large diameter end of the shaft was cut by 90 mm, and a commercially available rubber grip was attached with double-sided tape to prepare the golf club of the example. Table 5 shows the results of measuring the mass, club length, and balance of the putter golf club of this example.

(Example 2)
A shaft was produced in the same manner as in Example 1 except that the shaft was bent at the tip A of the uncured shaft from which the mandrel 10 was pulled out so that θ1 and θ2 became 130 ° while warming with a dryer. Although the shaft was crushed in the bending process, Table 4 shows the mass G of the obtained shaft, the total length L, the outer diameter at the position of 10 mm from the small diameter end and 25 mm from the large diameter end. Table 5 shows the results of producing a golf club for putters in the same manner as in Example 1 and measuring the mass, club length, and balance.

(Comparative Example 1)
Of the prepregs (patterns 1 and 2) cut into the shape shown in FIG. 3, pattern 1 is wound around the mandrel 10, and a 20 mm wide polypropylene shrinkage tape is wound around the mandrel 10 at a pitch of 2 mm to heat and cure. After peeling off the shrinking tape, the evaluation was carried out in the same manner as in Example 1 except that the pattern 2 shown in FIG. 3 was wound. Although the obtained tubular body had the desired shape, it had insufficient rigidity and did not have sufficient functions as a golf shaft for putters.

As is clear from the results in Table 5, the carbon fiber reinforced resin putter golf club shaft having the bent portion obtained in Examples 1 and 2 can have the same shape as the steel putter golf club. Moreover, since the weight can be reduced, it is possible to obtain a golf club for putters according to the application.

(Example 3)
A mandrel 11 (made of iron) having the shape shown in FIG. 4 was prepared. The mandrel 11 has an overall length L25, and its outer diameter gradually increases linearly from the small diameter end P21 to the position (first switching point) P22 of the length L21, and the length from the switching point P22. The outer diameter linearly increases up to the position (second switching point) P23 of L22, and the outer diameter linearly increases from the switching point P23 to the position (third switching point) P24 of the length L23. From the switching point P24 to the large diameter end P25 of length L24, the outer diameter thereof is constant, and it is made of an iron cylindrical body. The specific outer diameter, length, and taper degree of each part of the mandrel 11 according to this embodiment are as follows.

The outer diameter of the small diameter end P21 is 3.10 mm, the outer diameter of the first switching point P22 is 3.30 mm, the outer diameter of the second switching point P23 is 8.00 mm, and the outer diameter of the third switching point P24 is 10.50 mm. The switching point P24 to the large diameter end P25 have the same outer diameter, and the outer diameter is 10.50 mm. The length L21 from the small diameter end P21 to the first switching point P22 is 300 mm, the length L22 from the first switching point P22 to the second switching point P23 is 450 mm, and the length from the second switching point P23 to the third switching point P24. The length L23 is 100 mm, and the length L24 from the switching point P24 to the large diameter end P25 is 550 mm. The total length L25 of the mandrel 11 is 1400 mm. The taper degree from the small diameter end P21 to the first switching point P22 is 0.67 / 1000, the taper degree from the first switching point P22 to the second switching point P23 is 10.44 / 1000, and the taper degree is 10.44 / 1000, and the second switching point P23. The degree of taper from to the third switching point P24 is 25.00 / 1000.

Of the prepregs (patterns 1 to 8) cut into the shape shown in FIG. 5, pattern 1 and pattern 2 are wound around the mandrel 11, and a 20 mm wide polypropylene shrinkage tape is wound on the mandrel 11 at a pitch of 2 mm. It was heated and cured. In pattern 1 and pattern 2, the prepreg in which the carbon fibers (CF) are oriented at + 45 ° with respect to the axial direction of the mandrel and the prepreg in which the carbon fibers (CF) are oriented at −45 ° are substantially offset by half with respect to the mandrel 10. It is a stack of two sheets in this way.
The materials of the prepregs 4, 7 and 8 in FIG. 5 are shown in Table 1, and the sizes of the prepreg parts of the patterns 1 to 8 are shown in Table 3.

Further, the region around which the prepreg is wound in the mandrel 11 is set to a position from 150 mm measured from the small diameter end of the mandrel to a position of 985 mm toward the large diameter end. Wrap pattern 1 using prepreg 4 around mandrel 11, wrap pattern 2 using prepreg 7 on it, wrap 20 mm wide polypropylene shrinkage tape on it at a pitch of 2 mm, and then put it in a heating furnace. After heating and holding at 135 ° C. for 2 hours, the mandrel was naturally cooled to room temperature, the cured shaft was removed from the mandrel 11, and the shrinkage tape was peeled off.

After heat curing, the mandrel 11 was removed and the polypropylene shrinkage tape was peeled off to obtain a premolded shaft. Then, the pre-molded shaft is inserted into the mandrel 11 again, patterns 3 to 8 are wound around the pre-molded shaft in order, 20 mm wide polypropylene shrinkage tape is wound around the pre-molded shaft at a pitch of 2 mm, and then the mandrel 11 is wound again. I pulled it out. Pattern 8 corresponds to a hoop layer in which the winding angle of the reinforcing fiber with respect to the main shaft of the mandrel 11 is 90 °, and patterns 3 to 7 correspond to a straight layer in which the winding angle of the reinforcing fiber is 0 ° with respect to the main shaft of the mandrel 11. do.

Table 4 shows the mass G of the obtained shaft, the total length L, and the outer diameters at positions 10 mm from the small diameter end and 25 mm from the large diameter end. Further, in this embodiment, bending is performed at two points of 60 mm and 125 mm from the small diameter end portion, the respective angles are set to θ1 and θ2, and the respective values are shown in Table 4.

[Installation of golf club head and grip]
A commercially available putter head (mass 374 g) was attached to the small diameter end of the golf club shaft for putter of this embodiment with an acrylic resin adhesive. Further, the large diameter end of the shaft was cut by 90 mm, and a commercially available rubber grip was attached with double-sided tape to prepare the golf club of the example. Table 5 shows the results of measuring the mass, club length, and balance of the putter golf club of this example.

(Example 4)
A shaft was manufactured in the same manner as in Example 3 except that the shaft was bent so that θ1 became 130 ° while warming with a dryer at the tip A portion of the uncured shaft from which the mandrel 11 was extracted. Since the rigidity of the shaft is very high, the bent portion returns to an angle of 130 ° or more after heat curing, and distortion occurs in areas other than the bent portion. However, as in Example 3, a golf club for putters. Was able to be produced.

(Comparative Example 2)
Of the prepregs (patterns 1 to 3) cut into the shape shown in FIG. 6, pattern 1 and pattern 2 are wound around the mandrel 11, and a 20 mm wide polypropylene shrinkage tape is wound around the mandrel 11 at a pitch of 2 mm and heated. After curing and peeling off the shrinking tape, the evaluation was carried out in the same manner as in Example 3 except that the pattern 3 shown in FIG. 6 was wound. Although the desired shape was obtained, the rigidity was insufficient and the golf shaft for a putter did not have a sufficient function.

Since the tubular body of the present invention has a bent portion and is lightweight and has high rigidity, it can be used as a support member such as a stay of a rearview mirror of an automobile or a motorcycle, or as a reinforcing material such as a frame of a bicycle. In particular, it can be suitably used as a golf club shaft for putters.
Further, the method for manufacturing a tubular body of the present invention makes it possible to impart a bent portion to a tubular body on which a fiber-reinforced resin cured product layer in which fibers are continuous in the longitudinal direction is laminated, which has been difficult in the past. In particular, it can be suitably used as a method for manufacturing a golf club shaft for putters.

10 mandrel 11 mandrel

Claims (10)

A tubular body having a laminated structure of a fiber-reinforced resin cured product layer.
The tubular body has a bend and
In at least one layer of the fiber-reinforced resin cured product layer in the longitudinal direction including the bent portion, continuous fibers contained in the fiber-reinforced resin cured product layer are seamlessly arranged.
A tubular body in which a hoop layer in which the fibers of the fiber-reinforced resin cured product layer are oriented at an angle of 80 ° to 100 ° with respect to the longitudinal direction is laminated on the outermost layer of the bent portion. The tubular body according to claim 1, wherein the fiber-reinforced resin cured product layer is a carbon fiber-reinforced resin layer. It is composed of the tubular body according to any one of claims 1 or 2.
It consists of a tip part A and a main body part B.
The tip portion A has a tapered or straight shape having the bent portion at at least one position.
The main body B has a tapered or straight shape with substantially no bending in the longitudinal axis direction of the shaft.
A golf club shaft for a putter composed of the tip portion A and the main body portion B having no joint portion. The golf club shaft for a putter according to claim 3, wherein the hoop layer is arranged in a region corresponding to 200 mm from the head side end to the head side end of the shaft. When the angle of the bent portion of the tip portion A is θn (n is an integer), respectively.
135 ° ≤ θn <180 °
The golf club shaft for a putter according to claim 3 or 4 , which comprises the range of. A prepreg consisting of a layer whose fiber direction is oriented at + 30 to + 70 ° with respect to the longitudinal direction of the tubular body and a layer whose fiber direction is oriented at -30 to -70 ° is wound around a mandrel and then heat-cured to form a bias layer. And the process of obtaining the bias layer,
A winding step of winding a prepreg on the bias layer to form a straight layer whose fiber directions are aligned in the longitudinal direction of the tubular body.
After wrapping the tape in a spiral shape from above, the mandrel is removed to obtain the wrapping material, the process of obtaining the wrapping material, and
The process of heating the wound object and locally bending it, and bending it,
It has a process of heat-curing and heat-curing while maintaining a locally bent state.
The winding step is a step of winding the prepreg forming the auxiliary layer as well.
The auxiliary layer is a hoop layer in which the fibers of the fiber reinforced resin are oriented at 80 ° to 100 ° with respect to the longitudinal direction of the tubular body.
A method for producing a tubular body having a bent portion in which a continuous fiber-reinforced resin cured product layer is laminated, which bends the bias layer in the bending step. The method for manufacturing a tubular body according to claim 6 , wherein in the step of obtaining the bias layer, the prepreg is wound so as to seamlessly arrange fibers continuous in the longitudinal direction including the bent portion of the tubular body. The method for producing a tubular body according to claim 6 or 7 , wherein the fiber reinforced resin is a carbon fiber reinforced resin. In the bending step, when bending one or more places of the tubular body, when the bending angle of the tubular body is set to θn (n is an integer), respectively.
135 ° ≤ θn <180 °
The method for producing a tubular body according to any one of claims 6 to 8 , wherein the tubular body is manufactured within the range of. The method for producing a tubular body according to any one of claims 6 to 9 , wherein the matrix resin used for the prepreg is an epoxy resin.

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