Golf club shaft, golf club, and method for manufacturing golf club shaft

Abstract

A golf club shaft which is light in weight and at the same time exhibits an impact absorbing property at the time of impact by a golf ball to suppress vibration. The golf club shaft has a shaft body extending in the length direction, wherein the shaft body is composed of a composite material having a first member having a fiber reinforced plastic and a second member formed in direct contact with the first member in at least a part of the region of the first member and having a rubber material, the first member and the second member being integrated.

Description

Technical Field

[0001] The present invention relates to a golf club shaft made of a composite material having fiber-reinforced plastic and rubber materials, a golf club using the above-described golf club shaft, and a method for manufacturing the above-described golf club shaft. Background Technology

[0002] As materials for golf club shafts, steel and fiber-reinforced plastics (FRP) are used, considering both lightweight and strength. One proposed steel golf club shaft comprises a shaft body, a coating formed by chemically treating the outer and inner surfaces of the shaft body, a coating layer formed at least on the outer coating layer by electrodeposition, and a pigment layer coated on the coating layer and in which polarizing powder is dispersed (Patent Document 1).

[0003] In Patent Document 1, a pigment layer containing polarizing powder is formed on the coating layer formed by electrodeposition on the chemically treated film. Therefore, compared with the conventional golf club shaft formed by plating, it has excellent aesthetics, has rust prevention effect inside the shaft, and avoids the problem of increased weight of the golf club shaft due to plating, thus achieving lightweighting.

[0004] On the other hand, fiber-reinforced plastics (FRP) have been widely used in recent years as a material to replace steel for golf club shafts due to their combination of lightweight and high strength. For example, a golf club shaft made of carbon fiber reinforced plastic has been proposed, which is composed of a laminate of multiple resin-impregnated carbon fiber layers, wherein a resin layer formed of an epoxy resin composition is disposed between the layers of the resin-impregnated carbon fiber layers (Patent Document 2).

[0005] In Patent Document 2, by configuring an epoxy resin layer between the resin-impregnated fiber layers, the interlayer delamination of the resin-impregnated fiber layers is suppressed without reducing the elastic modulus of the golf club shaft made of fiber-reinforced plastic, thereby increasing the strength of the golf club shaft made of fiber-reinforced plastic.

[0006] On the other hand, golf clubs not only require lightweight and high strength, but also a clear feel (hitting sensation). To achieve this clear feel, the club shaft must possess shock-absorbing properties upon impact, thereby suppressing shaft vibration. For the golf club shafts in Patent Document 1 (made of steel) and Patent Document 2 (made of fiber-reinforced plastic layers and epoxy resin layers disposed between the fiber-reinforced plastic layers), there is room for improvement in suppressing shaft vibration upon impact to achieve a clear feel. (Existing technical literature) (Patent Documents)

[0007] Patent Document 1: Japanese Patent Application Publication No. 2010-246824 Patent Document 2: Japanese Patent Application Publication No. 2016-87460 Summary of the Invention The problem that the invention aims to solve

[0008] In view of the above, the object of the present invention is to provide a golf club shaft that is lightweight and has shock-absorbing properties to suppress vibration when a golf ball is hit, a golf club having the above-mentioned golf club shaft, and a method for manufacturing the above-mentioned golf club shaft. Methods for solving problems

[0009] The key features of this invention are as follows. [1] A golf club shaft having a shaft body extending in the length direction, wherein, The main body of the pole is made of a composite material, which has a first component and a second component. The first component is made of fiber-reinforced plastic. The second component is formed by direct contact between at least a portion of the first component and the first component, and is made of rubber material. The first component and the second component are formed as one piece. [2] According to the golf club shaft of [1], a portion of the first component is in direct contact with the second component, and there is no clamping or adhesive component between the first component and the second component. [3] The golf club shaft according to [1] or [2], wherein the first component and the second component are sheet-like and the composite material has a laminated structure. [4] The golf club shaft according to [1] or [2], wherein the rubber material is at least one selected from the group consisting of nitrile rubber, fluororubber, butyl rubber, ethylene propylene diene rubber, hydrogenated nitrile rubber and silicone rubber. [5] The golf club shaft according to [1] or [2], wherein the rubber material is at least one selected from the group consisting of nitrile rubber, fluororubber and butyl rubber. [6] The golf club shaft according to [1] or [2], wherein the fiber-reinforced plastic is carbon fiber reinforced plastic. [7] According to the golf club shaft of [1] or [2], wherein the first component is a multilayer structure having a first fiber-reinforced plastic and a second fiber-reinforced plastic, the first fiber-reinforced plastic forming a first layer with a fiber orientation angle in a first direction, and the second fiber-reinforced plastic forming a second layer with a fiber orientation angle in a second direction different from the first direction. [8] The golf club shaft according to [1] or [2], wherein the outer surface of the composite material is the first component. [9] According to the golf club shaft described in [1] or [2], the main body of the shaft has, from the base end side to the front end side in the length direction, a first region in which the outer diameter of the shaft decreases relatively gently, a second region in which the outer diameter of the shaft decreases relatively sharply, and a third region in which the relative change in the outer diameter of the shaft is minimal.

[10] A golf club having a clubhead and grip mounted on the shaft of the golf club described in [1] or [2].

[11] A method for manufacturing a golf club shaft, comprising: The process of preparing a first precursor, wherein the first precursor is an uncured or semi-cured material obtained by containing resin in fibers; The process of obtaining the laminate involves directly laminating a second precursor having uncured rubber onto at least a portion of the prepared first precursor, thereby obtaining a laminate of the first precursor and the second precursor. The process of winding the obtained laminate onto the outer periphery of a mandrel; The process of obtaining the wound composite material involves heat-treating the laminate wound on the outer peripheral surface of the mandrel to obtain a first component having fiber-reinforced plastic by thermosetting the resin of the first precursor and a second component having rubber material by vulcanizing the unvulcanized rubber of the second precursor; the first component and the second component are then integrated to obtain the wound composite material. The process of pulling out the mandrel from the wound composite material.

[12] In the method of manufacturing a golf club shaft according to

[11] , the second precursor is directly laminated on the prepared first precursor without adhesive members, the second precursor having unvulcanized rubber incorporating a vulcanizing agent. Invention Effects

[0010] According to an embodiment of the golf club shaft of the present invention, the golf club shaft has a shaft body extending in the length direction of the golf club. The shaft body is made of a composite material, which includes: a first member having multiple layers of fiber-reinforced plastic, and a second member having a rubber material formed in direct contact with at least a portion of the first member. The first member and the second member are integrated, thereby the second member having vibration damping properties. Therefore, upon impact with a golf ball, the shaft body exerts impact absorption characteristics to suppress vibration of the golf club shaft. Thus, according to the embodiment of the golf club shaft of the present invention, a clear feel can be given to the golf club. Furthermore, according to the embodiment of the golf club shaft of the present invention, the composite material constituting the golf club shaft, by including a first member having multiple layers of fiber-reinforced plastic, possesses both lightweight and strength. Additionally, according to the embodiment of the golf club shaft of the present invention, by integrating the first member having multiple layers of fiber-reinforced plastic with the second member having a rubber material, delamination between the first member and the second member can be prevented.

[0011] According to an embodiment of the golf club shaft of the present invention, by having a portion of the first member, which is stacked in multiple layers, in direct contact with the second member, and without any adhesive members sandwiched between the first member and the second member, uneven adhesion caused by adhesive members is prevented, thereby reliably preventing peeling between the first member and the second member.

[0012] According to an embodiment of the golf club shaft of the present invention, by using at least one rubber material selected from the group consisting of nitrile rubber, fluororubber, butyl rubber, ethylene propylene diene rubber, hydrogenated nitrile rubber and silicone rubber, a tight fit is obtained between the first component and the second component, thereby preventing peeling.

[0013] According to an embodiment of the golf club shaft of the present invention, by using at least one rubber material selected from the group consisting of nitrile rubber, fluororubber, and butyl rubber, a reliable seal is obtained between the first component and the second component, thereby reliably preventing peeling.

[0014] In an embodiment of the method for manufacturing a golf club shaft according to the present invention, a second precursor having uncured rubber is directly laminated onto at least a portion of an uncured or semi-cured material obtained by containing resin in fibers, i.e., a first precursor, to obtain a laminate. The laminate is then heat-treated to obtain a first component having fiber-reinforced plastic by heat-curing the resin in the first precursor and a second component having rubber material by vulcanizing the uncured rubber in the second precursor, and the first and second components are integrated. That is, by heat-treating the laminate, the uncured or semi-cured material obtained by containing resin in fibers, i.e., the prepreg, is heat-cured, thereby vulcanizing the uncured rubber, simultaneously obtaining fiber-reinforced plastic and vulcanized rubber material, and integrating the obtained fiber-reinforced plastic and vulcanized rubber material.

[0015] Therefore, according to an embodiment of the method for manufacturing a golf club shaft according to the present invention, when bonding the first component having fiber-reinforced plastic and the second component having rubber material, the adhesive coating process itself is not required, nor is uniform coating of the adhesive necessary. As can be seen from the above, the manufacturing method of the present invention can prevent the complexity of the manufacturing process of the composite material of fiber-reinforced plastic and rubber material, and can simplify the manufacturing of the golf club shaft. Furthermore, according to an embodiment of the method for manufacturing a golf club shaft according to the present invention, by heat-treating the laminate, a first component having fiber-reinforced plastic is obtained by thermosetting the resin of the first precursor, and a second component having rubber material is obtained by vulcanizing the unvulcanized rubber of the second precursor. Furthermore, by integrating the first component and the second component, a composite material of fiber-reinforced plastic and rubber material that prevents delamination between the first component and the second component can be prepared. As a result, a golf club shaft that is lightweight and has high strength, and exhibits shock absorption properties to suppress vibration upon impact with a golf ball, can be manufactured.

[0016] According to an embodiment of the method for manufacturing a golf club shaft of the present invention, by directly laminating the second precursor having unvulcanized rubber on the first precursor without via an adhesive member, uneven bonding caused by the adhesive member can be prevented, and thus peeling between the first and second components can be reliably prevented. Attached Figure Description

[0017] Figure 1 This is a schematic diagram showing a side view of a golf club having the shaft according to an embodiment of the present invention. Figure 2 This is a schematic diagram illustrating a portion of an embodiment of a composite material that constitutes the shaft body of a golf club shaft according to an embodiment of the present invention. Figure 3 This is a schematic diagram showing an outline of the front of the front end of the golf club shaft according to an embodiment of the present invention. Figure 4 This is a graph showing the vibration test results of the golf club shaft of the embodiment and the golf club shaft of the comparative example. Detailed Implementation

[0018] The golf club shaft of the present invention will now be described in detail. Figure 1 This is a schematic diagram showing a side view of a golf club having the shaft according to an embodiment of the present invention. Figure 2 This is a schematic diagram illustrating an embodiment of a composite material that constitutes the shaft body of a golf club shaft according to an embodiment of the present invention. Figure 3 This is a schematic diagram showing an outline of the front of the front end of the golf club shaft according to an embodiment of the present invention.

[0019] like Figure 1 As shown, the golf club 50 has a club shaft 100 extending along its length, a club head 200 mounted on the front end side (chip side) of the club shaft 100, and a grip 300 mounted on the base end side (butt side) of the club shaft 100.

[0020] The golf club shaft 100 has a shaft body 110 extending along its length. The shaft body 110 is a hollow cylindrical component. The golf club shaft 100 is configured such that the outer diameter of the shaft body 110 decreases with a predetermined taper from the base end side (thick end side) towards the tip end side (narrow end side).

[0021] like Figure 2As shown, the shaft body 110 is composed of a composite material 1 of fiber-reinforced plastic and rubber material. The composite material has a first member 10 of fiber-reinforced plastic and a second member 20 of rubber material formed in direct contact with at least a portion of the first member 10. The first member 10 and the second member 20 are integrally formed. By integrating the first member 10 and the second member 20, the composite material 1 constituting the shaft body 110 forms a joint 30 that joins the first member 10 to the second member 20, thus integrating the first member 10 and the second member 20. The composite material 1 is integrated while at least a portion of the first member 10 is in direct contact with the second member 20. Furthermore, in the composite material 1 constituting the shaft body 110, the first member 10 of fiber-reinforced plastic is arranged on both sides of the second member 20 of rubber material. Therefore, the second member 20 of rubber material is sandwiched between the first member 10 of fiber-reinforced plastic.

[0022] like Figure 2 As shown, in the joint 30 where the first member 10 and the second member 20 directly contact each other, there is no adhesive or other bonding component between the first member 10 and the second member 20. In the composite material 1, it is sufficient that at least a portion of the first member 10 is integrated with the second member 20 while in direct contact with it, and it is sufficient that at least a portion of the second member 20 is integrated with the first member 10 while in direct contact with it.

[0023] In composite material 1, the entire surface of the first member 10, which is opposite to the second member 20, is bonded to the second member 20 in direct contact with it. Similarly, the entire surface of the second member 20, which is opposite to the first member 10, is bonded to the first member 10 in direct contact with it. Therefore, in composite material 1, there are no clamping adhesive members in the entire joint 30 where the first member 10 and the second member 20 are opposite.

[0024] In the material constituting the main body 110, namely composite material 1, a portion of the surface portion of the fiber-reinforced plastic constituting the first member 10 and a portion of the matrix thereon enter the surface portion of the rubber material constituting the second member 20 and a portion of the surface portion of the rubber material constituting the second member 20 enter the surface portion of the fiber-reinforced plastic constituting the first member 10 and a portion thereon. Thus, the first member 10 and the second member 20 are joined to form a joint 30, and the first member 10 and the second member 20 are integrated. That is, in the joint 30 of composite material 1, the first member 10 provides an anchoring effect to the second member 20, and the second member 20 provides an anchoring effect to the first member 10, thereby integrating the first member 10 and the second member 20.

[0025] Regarding the shape of the composite material 1 constituting the main body 110, both the first component 10 and the second component 20 are sheet-like. Therefore, the composite material 1 has a sheet-like laminated structure.

[0026] Composite material 1 is a composite material of fiber-reinforced plastic and rubber material, comprising: a first component 10 having fiber-reinforced plastic, and a second component 20 having rubber material that is in direct contact with the first component 10 on at least a portion of its surface. The first component 10 and the second component 20 are integrated through the aforementioned anchoring effect, thereby preventing peeling between the first component 10 having fiber-reinforced plastic and the second component 20 having rubber material. Because the shaft body 110 is composed of the aforementioned composite material 1, the second component 20 having rubber material in the composite material 1 possesses vibration damping properties. Therefore, upon impact with a golf ball, the shaft body 110 exhibits impact absorption characteristics, suppressing the vibration of the golf club shaft 100. Thus, according to the embodiment of the golf club shaft 100 of the present invention, a clear feel can be given to the golf club 50. Furthermore, according to the embodiment of the golf club shaft 100 of the present invention, the composite material 1 constituting the shaft body 110 prevents peeling between the first component 10 and the second component 20 by firmly integrating the first component 10 having fiber-reinforced plastic and the second component 20 having rubber material.

[0027] Furthermore, in composite material 1, the first member 10 and the second member 20 are in direct contact throughout the entire joint 30, and no adhesive member is sandwiched between the first member 10 and the second member 20, thereby preventing uneven adhesion caused by adhesive members and thus reliably preventing peeling between the first member 10 and the second member 20.

[0028] Examples of fiber-reinforced plastics constituting the first component 10 include carbon fiber reinforced plastic (CFRP), glass fiber reinforced plastic (GFRP), aramid fiber reinforced plastic (AFRP), and cellulose fiber reinforced plastic. Among these, carbon fiber reinforced plastic is preferred from the perspective of possessing both lightweight and high strength suitable for a golf club shaft 100. The matrix resin of the fiber-reinforced plastic is not particularly limited in its composition. Specifically, thermosetting resins such as epoxy resin, phenolic resin, cyanate ester resin, vinyl ester resin, and unsaturated polyester resin can be used. The fiber-reinforced plastic constituting the first component 10 is a component formed by heat-curing an uncured (or semi-cured) thermosetting prepreg, which is an intermediate material obtained by impregnating the fibers with a matrix resin.

[0029] like Figure 2As shown, in composite material 1, the first component 10 is a multilayer structure having a first fiber-reinforced plastic layer 11 (11-1) with a fiber orientation angle in a first direction and a second fiber-reinforced plastic layer 11 (11-2) with a fiber orientation angle in a second direction different from the first direction. By forming the first component 10 into a multilayer fiber-reinforced plastic structure with different fiber orientation angles, the overall strength of the first component 10 in the planar direction is improved. It should be noted that... Figure 2 For ease of explanation, the first component 10 is described as a multi-layer structure consisting of two fiber-reinforced plastic layers 11. However, from the perspective of balancing the lightweight and strength of the golf club shaft 100, it can also be a multi-layer structure with three or more fiber-reinforced plastic layers 11. In the case of a multi-layer structure with three or more fiber-reinforced plastic layers 11, in addition to the first and second fiber-reinforced plastic layers 11, fiber-reinforced plastic layers 11 with different fiber orientation angles can be further provided, such as a third fiber-reinforced plastic layer 11 with a fiber orientation angle different from both the first and second directions, or a fourth fiber-reinforced plastic layer 11 with a fiber orientation angle different from the first, second, and third directions. Furthermore, depending on the need and from the perspective of the lightweight of the golf club shaft 100, the first component 10 can also be a structure consisting of a single fiber-reinforced plastic layer 11.

[0030] Examples of rubber materials used in the second component 20, which constitutes the main shock-absorbing component of the shaft body 110, include acrylonitrile-butadiene rubber (NBR), fluororubber (FKM), butyl rubber (IIR), ethylene propylene diene rubber (EPDM), hydrogenated nitrile butadiene rubber (HNBR), silicone rubber, urethane rubber, acrylic rubber (ACM), isoprene rubber (IR), styrene rubber (SBR), butadiene rubber (BR), ethylene propylene rubber (EPM), chloroprene rubber (CR), chlorinated polyethylene, and natural rubber (NR). These rubber materials can be used alone or in combination of two or more. The rubber material constituting the second component 20 is a component formed by vulcanizing unvulcanized rubber through heat treatment or other methods.

[0031] Among these rubber materials, nitrile rubber, fluororubber, butyl rubber, ethylene propylene diene rubber, hydrogenated nitrile rubber, and silicone rubber are preferred from the perspective of achieving a tight seal between the first component 10 and the second component 20, thereby giving the shaft body 110 excellent strength. Nitrile rubber, fluororubber, and butyl rubber are particularly preferred from the perspective of reliably achieving a tight seal between the first component 10 and the second component 20, thereby reliably giving the shaft body 110 excellent strength.

[0032] It should be noted that, in addition to rubber material, vulcanizing agent is also included in the second component 20. Furthermore, depending on the usage conditions of the main body 110, in addition to the rubber material containing vulcanizing agent, various additives such as antioxidants, processing aids, tackifiers, vulcanization accelerators, fillers, plasticizers, and vulcanization accelerators may also be added as needed.

[0033] The specific laminated structure of the first member 10 and the second member 20 in the composite material 1 constituting the shaft body 110 will be described. The composite material 1 constituting the shaft body 110 has a laminated structure in which at least the outer surface of the composite material 1, which forms the main surface, is provided with the first member 10. That is, the outer surface of the shaft body 110 is the first member 10 of the composite material 1, which is made of fiber-reinforced plastic. The layer of the second member 20, which is made of rubber material, is, for example, between the layers of the first member 10, which is made of fiber-reinforced plastic. The layer of the second member 20, which is made of rubber material, can be a single layer or multiple layers, or layers of the first member 10, which are composed of single or multiple layers of fiber-reinforced plastic 11, can be further sandwiched between the layers of the second member 20. The number of layers of the first member 10, the number of layers of fiber-reinforced plastic 11, and the number of layers of the second member 20 in the composite material 1 can be appropriately selected according to the usage conditions of the shaft body 110 and the required performance. However, the second component 20 is preferably not disposed on the outermost or innermost layer of the main body 110, but rather disposed between the layers of the first component 10.

[0034] For the pole body 110 made of composite material 1 with the outer surface of the first component 10 and a second component 20 of rubber material sandwiched between the layers of the first component 10, the deformation amount that leads to fracture due to deflection and bending is increased, and the deformation resistance of the pole body 110 is improved. In addition, for the pole body 110 made of composite material 1 with the outer surface of the first component 10 and a second component 20 sandwiched between the layers of the first component 10, the vibration damping is improved.

[0035] The shaft body 110 has three regions, namely a first region, a second region, and a third region, extending from the base end towards the front end along its length. In the first region, the outer diameter of the shaft body 110 decreases relatively gently from the base end towards the front end along its length. In the second region, the outer diameter of the shaft body 110 decreases relatively sharply from the base end towards the front end along its length. In the third region, the relative change in the outer diameter of the shaft body 110 along its length is minimal. The shaft body 110 is approximately straight, for example. A grip 300 is mounted on the outer circumferential surface of the first region of the shaft body 110.

[0036] Next, the manufacturing method of the golf club shaft of the present invention will be described. The golf club shaft of the present invention uses the above-described composite material 1 of fiber-reinforced plastic and rubber material as the material, the composite material 1 having: a first component 10 having fiber-reinforced plastic and a second component 20 having rubber material formed in direct contact with the first component 10, the first component 10 and the second component 20 being integral.

[0037] The method for manufacturing a golf club shaft of the present invention comprises: (1) a step of preparing a first precursor, wherein the first precursor is an uncured or semi-cured material obtained by containing resin in fibers; (2) a step of obtaining a laminate, wherein a second precursor having uncured rubber is directly laminated on at least a portion of the prepared first precursor to obtain a laminate of the first precursor and the second precursor; (3) a step of winding the obtained laminate onto the outer peripheral surface of a mandrel; (4) a step of obtaining a wound composite material 1, wherein the laminate wound on the outer peripheral surface of the mandrel together with the mandrel is heat-treated to obtain a first component 10 having fiber-reinforced plastic by heat curing the resin of the first precursor and a second component 20 having rubber material by curing the uncured rubber of the second precursor, thereby integrating the first component 10 and the second component 20 to obtain the wound composite material 1; and (5) a step of pulling the mandrel out of the wound composite material 1. The above-described method for manufacturing the golf club shaft of the present invention is known as the flat wire winding forming method.

[0038] (1) The process of preparing an uncured or semi-cured material, i.e., the first precursor, by containing resin in fibers. This is a process for preparing a prepreg (i.e., the first precursor), which is an uncured or semi-cured material made by containing a resin such as a thermosetting resin with reinforcing fibers such as carbon fibers. A single-layer prepreg can be used as the first precursor, or a laminated prepreg made by stacking multiple prepregs can be used. The number of layers of the prepreg can be appropriately selected based on the usage conditions of the golf club shaft, the required performance, etc.

[0039] (2) The process of directly laminating a second precursor having uncured rubber onto a first precursor to obtain a laminate. This process involves laminating a second precursor, having uncured rubber, onto the surface of a (laminated) prepreg, which serves as a first precursor, to obtain a laminated body. In this process, the second precursor, having uncured rubber, is directly laminated onto the first precursor without any adhesive members. When laminating the second precursor onto the first precursor, the laminated body of the first and second precursors may, as needed, be subjected to processes such as stamping. The laminated body obtained in this process is a precursor for a composite material.

[0040] (3) The process of winding the obtained laminated material onto the outer periphery of the mandrel. Prepare a mandrel with an outer diameter shape having a relatively gentle conical surface for forming the first region, a relatively sharp conical surface for forming the second region, and a portion with minimal relative variation for forming the third region. Next, a laminate on which the second precursor is deposited on the first precursor is wound around the outer circumferential surface of the mandrel.

[0041] (4) Process for obtaining the wound composite material 1 In the process of obtaining the wound composite material 1, while the laminate containing the first precursor and the second precursor is wound around the outer periphery of the mandrel, a heat-shrinkable tape or the like is spirally wound relative to the length direction, and the laminate is subjected to heat treatment. By heat treatment of the laminate, the resin of the first precursor is thermocured, and fiber-reinforced plastic is formed from the prepreg, resulting in a first component 10 having fiber-reinforced plastic. The uncured rubber of the second precursor is vulcanized, resulting in a second component 20 having rubber material. The first component 10 and the second component 20 are then integrated to obtain the wound composite material 1. That is, in the process of obtaining the wound composite material 1, by heat treatment of the laminate containing the first precursor and the second precursor, the uncured or semi-cured material, i.e., the prepreg, which contains resin in the fibers, is thermocured, and the uncured rubber is vulcanized, simultaneously obtaining fiber-reinforced plastic and vulcanized rubber material, and then integrating the obtained fiber-reinforced plastic and vulcanized rubber material. When fiber-reinforced plastic is formed from prepreg, a portion of the resin constituting the first precursor enters into the uncured rubber constituting the second precursor, and when the uncured rubber is vulcanized to form a rubber material, a portion of the uncured rubber constituting the second precursor enters into the resin constituting the first precursor. Through the interaction of the first and second precursors described above, the first component 10 and the second component 20 are joined to form a joint 30, thereby integrating the first component 10 and the second component 20. As a result, a joint 30 is formed in which a portion of the matrix resin on and near the surface of the fiber-reinforced plastic constituting the first component 10 enters into and near the surface of the rubber material constituting the second component 20, and a portion of the surface of and near the rubber material constituting the second component 20 enters into and near the surface of the fiber-reinforced plastic constituting the first component 10. This wound composite material 1 becomes a golf club shaft 100.

[0042] As a method for heat-treating a laminate of the first precursor and the second precursor, suitable heat treatment conditions for the first precursor can be appropriately selected.

[0043] (5) The process of pulling out the mandrel By pulling the mandrel out of the wound composite material 1, the mandrel can be removed from the composite material 1, thereby enabling the manufacture of the golf club shaft 100 of the present invention.

[0044] According to an embodiment of the golf club shaft manufacturing method of the present invention, when integrating the first component 10 having fiber-reinforced plastic and the second component 20 having rubber material, the adhesive coating process itself is not required, and therefore, uniform adhesive coating is also not required. As can be seen from the above, the manufacturing process of the composite material 1 of fiber-reinforced plastic and rubber material can be prevented from becoming complicated, and the manufacturing of the golf club shaft 100 can be simplified. Furthermore, in the golf club shaft manufacturing method of the present invention, by heat-treating the laminate of the first precursor and the second precursor, a first component 10 having fiber-reinforced plastic is obtained by thermosetting the resin of the first precursor, and a second component 20 having rubber material is obtained by vulcanizing the unvulcanized rubber of the second precursor, and the first component 10 and the second component 20 are firmly integrated, thus enabling the preparation of a composite material 1 of fiber-reinforced plastic and rubber material that prevents peeling between the first component 10 having fiber-reinforced plastic and the second component 20 having rubber material. As a result, it is possible to manufacture a golf club shaft 100 that is lightweight and high-strength, and that suppresses vibration by absorbing impact when a golf ball is hit.

[0045] Furthermore, according to an embodiment of the golf club shaft manufacturing method of the present invention, by directly laminating uncured rubber on the first precursor without via an adhesive member, uneven bonding caused by the adhesive member can be prevented, thereby preventing peeling between the first member 10 and the second member 20. Example

[0046] Next, embodiments of the golf club shaft of the present invention will be described, but the golf club shaft of the present invention is not limited to the following embodiments. It should be noted that... Figure 4 This is a graph showing the vibration test results of the golf club shaft of the embodiment and the golf club shaft of the comparative example.

[0047] <Example> A prepreg, a semi-cured material obtained by incorporating thermosetting resin into carbon fibers, is used as the first precursor. Uncured nitrile rubber is laminated onto the first precursor as the second precursor. Then, the first precursor is laminated onto the second precursor, thus preparing a laminate (a laminate of the first and second precursors) with layers of the second precursor sandwiched between the layers of the first precursor. The resulting laminate is wound around the outer circumference of a mandrel and heat-treated at 130°C for 90 minutes to obtain a composite material integrating a first component with fiber-reinforced plastic and a second component with rubber material. The mandrel is then pulled out from the wound composite material to manufacture a golf club shaft made of the composite material.

[0048] <Comparative Example> Instead of golf club shafts made of composite materials, steel golf club shafts are used.

[0049] Vibration test For the golf club shafts of the embodiments and comparative examples, both ends were treated as free ends, and sensors were installed on the upper part to cause vibration of the lower part for vibration testing. The results of the vibration tests are shown below. Figure 4 .

[0050] like Figure 4 As shown, in the embodiment using a golf club shaft made of a composite material integrally formed of a first component of fiber-reinforced plastic and a second component of rubber material, it is evident that the golf club shaft exhibits shock absorption characteristics. Therefore, upon impact with a golf ball, it suppresses vibration by absorbing shock, and the golf club provides a clear feel upon impact. In the comparative example using a steel golf club shaft, it is evident that the golf club shaft does not fully utilize its shock absorption characteristics. Therefore, upon impact with a golf ball, it does not exhibit shock absorption characteristics, and the golf club does not provide a clear feel upon impact. Industrial availability

[0051] The golf club shafts and clubs of the present invention are of great value to golfers, for example, in providing golf club shafts and clubs that are lightweight, strong, and provide a clear (realistic) feel on the ball. Symbol Explanation

[0052] 1 Composite material; 10 First component; 11 Fiber-reinforced plastic layer; 20 Second component; 100 Golf shaft; 110 Shaft body.

Claims

1. A golf club shaft having a shaft body extending in the longitudinal direction, wherein, The main body of the pole is made of a composite material, which has a first component and a second component. The first component is made of fiber-reinforced plastic, and the second component is formed by direct contact between at least a portion of the first component and the first component, and is made of rubber material. The first component and the second component are integrally formed. The shaft body has, from the base end to the front end along the length direction, the following regions in sequence: a first region where the outer diameter of the shaft decreases relatively gently, a second region where the outer diameter of the shaft decreases relatively sharply, and a third region where the relative change in the outer diameter of the shaft is minimal.

2. The golf club shaft according to claim 1, wherein, A portion of the first component is in direct contact with the second component, and there is no adhesive component between the first component and the second component.

3. The golf club shaft according to claim 1 or 2, wherein, The first component and the second component are sheet-like, and the composite material has a laminated structure.

4. The golf club shaft according to claim 1 or 2, wherein, The rubber material is selected from at least one of the following groups: nitrile rubber, fluororubber, butyl rubber, ethylene propylene diene rubber, hydrogenated nitrile rubber, and silicone rubber.

5. The golf club shaft according to claim 1 or 2, wherein, The rubber material is at least one selected from the group consisting of nitrile rubber, fluororubber, and butyl rubber.

6. The golf club shaft according to claim 1 or 2, wherein, The fiber-reinforced plastic is a carbon fiber-reinforced plastic.

7. The golf club shaft according to claim 1 or 2, wherein, The first component is a multilayer structure having the first fiber-reinforced plastic and the second fiber-reinforced plastic, wherein the first fiber-reinforced plastic forms a first layer with a fiber orientation angle in a first direction, and the second fiber-reinforced plastic forms a second layer with a fiber orientation angle in a second direction different from the first direction.

8. The golf club shaft according to claim 1 or 2, wherein, The outer surface of the composite material is the first component.

9. A golf club having a clubhead and a grip mounted on the shaft of a golf club as described in claim 1 or 2.

10. A method for manufacturing a golf club shaft, comprising the following steps: The process of preparing a first precursor, wherein the first precursor is an uncured or semi-cured material obtained by containing resin in fibers; The process of obtaining the laminate involves directly laminating a second precursor having uncured rubber onto at least a portion of the prepared first precursor, thereby obtaining a laminate of the first precursor and the second precursor. The process of winding the obtained laminate onto the outer circumferential surface of the mandrel; The process of obtaining the wound composite material involves heating the laminate wound on the outer peripheral surface of the mandrel to obtain a first component having fiber-reinforced plastic by thermosetting the resin of the first precursor and a second component having rubber material by vulcanizing the unvulcanized rubber of the second precursor, and integrating the first component and the second component to obtain the wound composite material. and The process of pulling the mandrel out of the wound composite material.

11. The method for manufacturing a golf club shaft according to claim 10, wherein, The second precursor, having uncured rubber incorporating a vulcanizing agent, is directly laminated onto the prepared first precursor without via an adhesive member.

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