JP5326484B2 - Manufacturing method of shaft for golf club - Google Patents

Description

  The present invention relates to a method for manufacturing a golf club shaft, and more specifically, even if the surface of a tapered cylindrical laminate formed by braiding base fibers by a braiding method is polished after curing, the strength is reduced. It is related with the manufacturing method of the shaft for golf clubs which can suppress shaft bending and can prevent shaft breakage.

  As a method for manufacturing a golf club shaft, a sheet winding method and a braiding method are known (see, for example, Patent Document 1). In the sheet winding method, a prepreg sheet in which a large number of base fibers impregnated with a resin material are juxtaposed in one direction is wound around a mandrel to form a tapered tubular laminate. In the braiding method, base fibers are braided on a mandrel at a symmetrical orientation angle with respect to the shaft axis direction to form a braided layer, and a plurality of the braided layers are laminated to form a tapered cylindrical laminate.

  In both production methods, after the laminate is molded, the resin material impregnated in the base fiber is cured, and then the surface of the cured laminate is subjected to post-processing steps such as shaft frequency adjustment and painting. For polishing. Next, the surface of the polished laminate is painted to complete the shaft.

By the way, in the braiding method, since the braided layer of the laminate is configured so that the base fiber is knitted up and down, the base fiber is not polished by polishing even if the amount of polishing is less than that of the laminate of the sheet winding method. There was a problem that it was easy to disconnect. In particular, since the tip portion having a relatively small diameter in the laminate has a relatively low strength, the breakage of the base fiber is a major factor that causes the manufactured shaft to be broken. Therefore, when the braiding method is used, there is a need for a method that can prevent shaft breakage by suppressing a decrease in strength even if the surface of the cured tapered cylindrical laminate is polished.
JP 2002-177424 A

  An object of the present invention is to provide a golf club capable of preventing shaft breakage by suppressing a decrease in strength even when the surface of a tapered cylindrical laminate formed by braiding base fibers by a braiding method is polished after curing. It is in providing the manufacturing method of a shaft.

In order to achieve the above object, a golf club shaft manufacturing method according to the present invention includes a cylindrical braided layer formed by braiding base fibers impregnated with a resin material at a predetermined orientation angle with respect to the shaft axial direction. After laminating a plurality of layers, a tapered tubular laminate was formed by a braiding process, and then the impregnated resin material was cured by heating the laminate, and then the surface of the cured laminate was polished. Later, in the golf club shaft manufacturing method in which a post-processing step is performed , when forming the tapered cylindrical laminate, the outermost braided layer of the laminate with respect to at least the tip region of the laminate, When a protective material is inserted between the outermost layer and the braided layer on the inner circumferential side, and the laminate is heated, the protective material is cured and integrated with the laminate, and the surface of the laminate is polished. When protecting Region was inserted in the laminate substantially polished until protective material so as to polish only the outermost layer and the protective material, the uneven surface of the stack of braided layers of the inner peripheral side than the protective member The convex portion is left as it is, and the concave portion is filled with a protective material to smooth the surface of the laminate.

  In the present invention, the protective material can be covered only within a range of 300 mm from the tip of the laminate. A prepreg sheet in which a large number of base fibers impregnated with a resin material are juxtaposed in one direction can also be used as a protective material. The thickness of the protective material is, for example, 0.05 mm or more and 1.0 mm or less.

  According to the present invention, a tapered tubular laminate formed by laminating a plurality of tubular braid layers formed by braiding base fibers impregnated with a resin material at a predetermined orientation angle with respect to the shaft axial direction. Provide a protective material on the inner surface of the laminate or the outermost braided layer of the laminate for at least the tip area of the body, and cure it before performing post-treatment steps such as painting. When polishing the surface of the laminated body, the area covered with the protective material is substantially smoothed by polishing only the protective material, or the area where the protective material is inserted is substantially protective material. Because the surface is smoothed by polishing, the tip of the braided structure that has a relatively small diameter in which the strength is likely to decrease even with a small amount of polishing is protected by a protective material. . As a result, the strength of the front end portion of the laminated body does not decrease from that of the original laminated body by polishing, so that a shaft that is not easily broken can be obtained.

  A method for manufacturing a golf club shaft (hereinafter referred to as shaft 1) of the present invention will be described based on the embodiments shown in the drawings.

  First, in order to mold the laminate 2 illustrated in FIGS. 1 and 2, a resin material is used so as to cover the outer peripheral surface of the mandrel whose diameter is increased from one end in the longitudinal direction to the other end using a braiding device. A plurality of impregnated base fibers 3 are braided at a predetermined orientation angle a with respect to the shaft axial direction of the shaft 1 to be manufactured (that is, the axial direction of the mandrel) and wound to form a cylindrical first braided layer 2a. Form. Similarly, the second braided layer 2b is formed on the outer peripheral surface of the first braided layer 2a, and the third braided layer 2c is similarly formed on the outer peripheral surface of the second braided layer 2b. In this manner, the plurality of braided layers 2a to 2c are coaxially stacked with the shaft axis CL as the center, thereby forming the tapered cylindrical stacked body 2.

In this reference embodiment , the cylindrical layered body 2 is formed by laminating three layers of the first braided layer 2a, the second braided layer 2b, and the third braided layer 2c. Is set. Similarly, an appropriate number of base fibers 3 is set. An appropriate angle is also set for the orientation angle a of the base fiber 3. The orientation angle a is, for example, about 10 ° to 45 °.

  Examples of the base fiber 3 include carbon fiber, aramid fiber, metal fiber, glass fiber, and boron fiber. As a resin material to be impregnated into the base fiber 3, a thermosetting resin such as an epoxy resin or an unsaturated polyester resin is used.

  After the tapered cylindrical laminate 2 is formed, at least a tip portion of the surface of the laminate 2 is covered with the protective material 4 as illustrated in FIGS. Since the laminated body 2 (braided layers 2a to 2c) is configured so that the base fiber 3 is knitted up and down, the surface is uneven to some extent.

  Next, the resin material impregnated by heating the laminate 2 is cured. When the laminate 2 is heated, the protective material 4 is cured and integrated with the laminate 2.

  Although the protective material 4 can be coated on the entire surface of the laminate 2, there are disadvantages such as high cost and heavy weight. Therefore, it is only necessary to coat the region of the front end portion of the laminate 2. The tip of the laminate 2 is a region that has a relatively small diameter and is likely to be broken by a ball impact when it becomes the shaft 1 due to insufficient strength. For example, the range of 300 mm from the tip of the laminate 2 is the tip of the laminate 2. Therefore, the protective material 4 can be covered only on the surface within a range of 300 mm from the tip of the laminate 2.

  Examples of the protective material 4 include a prepreg sheet in which a large number of base fibers impregnated with a resin material are arranged in one direction. In addition, as the protective material 4, a member that is cured by heating and can be integrated with the laminate 2 can be used. Since the protective material 4 only needs to protect the laminated body 2 and prevent disconnection of the base fiber 3 during polishing as will be described later, it is not necessary to have high strength like a reinforcing member.

  Next, after the laminate 2 and the protective material 4 are cured and integrated, for example, the uneven surface of the cured laminate 2 is polished for a post-processing step such as frequency adjustment or painting. In this polishing, the region covered with the protective material 4 is substantially polished only by the protective material 4 so as not to polish the laminate 2 (base material fiber 3), as illustrated in FIG. Smooth. In FIG. 4, the dotted lines indicate the surfaces of the laminate 2 and the protective material 4 before polishing. Therefore, the convex part of the surface of the laminated body 2 of the area | region covered with the protective material 4 remains as it is, and a recessed part will be in the state filled with the hardened protective material 4. FIG.

  In the laminated body 2, a region having a somewhat large diameter (a region other than the tip portion) can be smoothed by slightly polishing the laminated body 2 (base fiber 3). This is because such a relatively large-diameter region can ensure sufficient strength, so that the manufactured shaft 1 does not break.

  After the surface of the laminate 2 is polished and smoothed, a post-treatment process is performed. Examples of the post-treatment process include surface coating. By applying a paint to the surface of the polished laminate 2, the shaft 1 having the outermost layer as illustrated in FIG. 5 covered with the paint layer 5 can be obtained.

As described above, in the reference embodiment of the present invention , even if the polishing amount is small, the base fiber 3 is disconnected, and the strength of the braided structure 2 is easily reduced. The part is protected by the protective material 4. Therefore, even if it grind | polished at the front-end | tip part of the laminated body 2, the disconnection of the base fiber 3 does not arise, and intensity | strength does not fall rather than the original laminated body 2. FIG. Therefore, it is possible to obtain the shaft 1 which is less likely to be broken while suppressing the strength reduction due to polishing while using the braiding method.

The protective material 4 is not only provided on the surface of the laminate 2 as in the above reference embodiment , but also the outermost braided layer of the laminate 2 and the braided layer on the inner peripheral side from the outermost layer as in the present invention. It can also be inserted between the two. In this case, when the tapered cylindrical laminate 2 is formed, the outermost braided layer of the laminate 2 and the innermost layer from the outermost layer with respect to at least the tip end region of the laminate 2. When the protective material 4 is inserted between the braided layers and the laminated body 2 is heated, the protective material 4 is cured and integrated with the laminated body 2. When the surface of the laminate 2 is polished, the region in which the protective material 4 is inserted is substantially polished up to the protective material 4 so as to be smooth.

For example, when the laminate 2 has a three-layer structure of the first braided layer 2a, the second braided layer 2b, and the third braided layer 2c, the third braided layer 2c and the second braided layer are exemplified as shown in FIG. The protective material 4 is inserted between 2b. When the surface of the laminate 2 is polished, only the third braided layer 2c and the protective material 4 are polished, and the braided layer (second braided layer 2b) on the inner peripheral side of the protective material 4 is polished. Finish the surface smoothly without having to.

When the unevenness of the outermost braided layer (third braided layer 2c) of the laminate 2 is large, the outermost braided layer can also be used as a margin for polishing. Also in this case, the tip of the laminate 2 is protected by the protective material 4 during the surface polishing, as in the previous reference embodiment . Therefore, even if the front end portion of the laminate 2 is polished, the disconnection of the base fiber 3 can be minimized, and the strength reduction can be suppressed with respect to the original laminate 2. Therefore, it is possible to obtain the shaft 1 which is less likely to be broken while suppressing the strength reduction due to polishing while using the braiding method.

  In the present invention, the thickness of the protective material 4 when the surface of the laminate 2 is coated is preferably set to 0.05 mm or more and 1.0 mm or less. This is because when the thickness of the protective material 4 is less than 0.05 mm, it is difficult to smooth the surface while preventing the base fiber 3 from being disconnected when polishing the surface of the uneven laminate 2. . On the other hand, if the thickness of the protective material 4 exceeds 1.0 mm, the amount of polishing increases, which causes a reduction in manufacturing efficiency.

Five types of shafts ( reference examples and comparative examples 1 to 3) were prepared by laminating five cylindrical braided layers and using a braiding method. For each shaft, the orientation angle of the base fiber from the inner peripheral side is 45 ° (first layer), 45 ° (second layer), 20 ° (third layer), 20 ° (fourth layer), 20 °. As shown in Table 1, the (fifth layer) was specified so that only the presence / absence of coating of the protective material and the presence / absence of shaft surface polishing differed from the outermost layer (fifth layer). As the protective material, a large number of prepreg sheets (thickness 0.125 mm) arranged in parallel in one direction of the base fiber impregnated with the resin material were used. The position where the protective material is coated is in a range of 100 mm from the tip of the shaft.

That is, the reference example is obtained by polishing the surface of Comparative Example 1 until it is smooth, and Comparative Example 2 is obtained by polishing the surface of Comparative Example 3 until it is smooth.

  With respect to these four types of shafts, a range of 40 mm from the tip was fixed in a cantilever state by a fixing jig, a load was applied to a position 190 mm from the tip, and the bending length was 150 mm, and a bending test was performed. The results are shown in Table 1. The numerical values of bending strength in Table 1 are average values of three test samples (n = 3), respectively.

From the results in Table 1, the reference example in which the outermost layer was coated with a protective material and the surface was polished had a slight decrease in bending strength compared to Comparative Example 1 in which the surface was not polished, and the outermost layer was protected with a protective material. It can be seen that Comparative Example 2 in which the surface is polished without coating has a significantly lower bending strength than Comparative Example 3 in which the surface is not polished. Thus, it can be seen that the protective material coated on the shaft surface is very effective in preventing a reduction in the bending strength of the shaft due to surface polishing.

It is a front view which illustrates the tapered cylindrical laminated body which coat | covered the protective material on the surface. It is AA sectional drawing of FIG. FIG. 2 is a longitudinal half sectional view schematically enlarging and illustrating a periphery of a distal end portion of the tapered cylindrical laminate of FIG. 1. FIG. 4 is a longitudinal half sectional view schematically exemplifying a state after polishing the surface of the laminated body of FIG. 3. FIG. 5 is a longitudinal half sectional view schematically exemplifying a shaft completed by applying a coating to the surface of the laminate of FIG. 4. It is a longitudinal half sectional view which expands and illustrates typically the front-end | tip part periphery of the tapered cylindrical laminated body which inserted the protective material.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shaft 2 Laminated body 2a 1st braided layer 2b 2nd braided layer 2c 3rd braided layer 3 Base fiber 4 Protective material 5 Paint layer

Claims (4)

  A plurality of tubular braid layers formed by braiding base fibers impregnated with a resin material at a predetermined orientation angle with respect to the shaft axis direction are laminated, and a tapered tubular laminate is formed by a braiding method. Then, in the golf club shaft manufacturing method in which the resin material impregnated by heating the laminated body is cured, and then the surface of the cured laminated body is polished, a post-treatment process is performed. When forming the cylindrical laminate, a protective material is provided between the outermost braided layer and the innermost braided layer from the outermost layer with respect to at least the tip region of the laminate. When the laminate is heated and the laminate is heated, the protective material is cured and integrated with the laminate, and when the surface of the laminate is polished, the region where the protective material is inserted is the most part of the laminate. Only polish the outer layer and protective material Polish up to the protective material qualitatively, leave the projections on the uneven surface of the laminate consisting of the braided layer on the inner circumference side of the protective material, and leave the concave portions filled with the protective material. Of manufacturing a golf club shaft that smoothens the surface of the golf club. The golf club shaft manufacturing method according to claim 1 , wherein the protective material is covered only within a range of 300 mm from the tip of the laminate. The golf club shaft manufacturing method according to claim 1 , wherein the protective material is a prepreg sheet in which a large number of base fibers impregnated with a resin material are arranged in one direction. The method for manufacturing a golf club shaft according to any one of claims 1 to 3 , wherein the protective material has a thickness of 0.05 mm to 1.0 mm.

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