JP5748094B2 - Golf club shaft - Google Patents

Description

  The present invention relates to a golf club shaft.

  In golf clubs, the balance, that is, the position of the center of gravity as a club, can be cited as a major factor that determines the swing comfort and the ease of returning the head. The position of the center of gravity is generally adjusted by changing the weight of the golf club head or grip. However, it is difficult to perform sufficient balance adjustment only by adjusting the weight of the head and grip, and it is required to adjust the club balance by adjusting the center of gravity of the shaft.

  Regarding the adjustment of the center of gravity of the shaft, in Patent Document 1 (Japanese Patent No. 3691916), a step portion is formed at the tip of the mandrel, and a material having a heavy specific gravity, such as metal, is disposed in the step portion. It is disclosed to perform a balance adjustment. However, when such a step portion is formed, the metal layer is disposed in the innermost layer, and thus there is a problem that the metal layer is peeled off during use of the club. Further, when assembled as a club, standard lead is often inserted at the tip for balance adjustment. When the step portion is formed at the tip of the mandrel for the purpose of adjusting the center of gravity, there is a problem that the lead inner diameter of the shaft becomes too small to insert standard lead.

  As a technique that can solve such a problem, Patent Document 2 (Japanese Patent No. 3216728) can be cited. In Patent Document 2, a metal layer is formed in a layer other than the innermost layer and the outermost layer in order to prevent the problem of peeling and inner diameter. However, in this method, since the outer diameter changes, the bending rigidity value (EI) of the metal layer insertion portion changes, and there is a problem that it is not possible to purely adjust the balance.

  As described above, the mandrel has to be stepped and the bending stiffness value changes, which reduces the degree of freedom in adjustment during design, head selection, and club assembly, and the desired bending stiffness value cannot be obtained. Was left.

Japanese Patent No. 3691916 Japanese Patent No. 3216728

  An object of the present invention is to provide a golf shaft that can change only the center of gravity without changing the inner diameter and the bending rigidity value. This increases the degree of freedom of adjustment when designing the shaft, selecting the head, and assembling the club.

The above problems are solved by the following invention.
In a golf club shaft formed by laminating a plurality of fiber reinforced composite material layers having an angle layer and a straight layer, at least one of the angle layer and / or the straight layer is a plurality of prepregs satisfying the following [1] to [3] formed of a composite material layer made of, by weight per unit area of below lightweight unit 4 and the following parts by weight 3 1: golf shafts, characterized in that not less than 1.5.
[1] It has a weight part 3 in which a lightweight part 4 and metal powder are mixed ,
[2] The thickness of the light unit 4 and the parts 3 are substantially the same,
[3] the lightweight portion 4 and the elastic modulus of the weight part 3 are substantially the same.

  According to the golf club shaft of the present invention, only the weight distribution can be changed without changing the inner diameter and the bending rigidity value.

It is the schematic explanatory drawing which showed an example of embodiment of the shaft for golf clubs of this invention. It is the schematic explanatory drawing which showed the comparative example 1 of this invention. It is the schematic explanatory drawing which showed the comparative example 2 of this invention. It is the schematic explanatory drawing which showed the comparative example 3 of this invention. It is the schematic explanatory drawing which showed Example 2 of this invention. It is the schematic explanatory drawing which showed Example 3 of this invention. It is the schematic explanatory drawing which showed Example 4 of this invention.

  Hereinafter, the golf club shaft of the present invention will be described in detail. FIG. 1 shows an example of an embodiment of a golf club shaft of the present invention. FIG. 1 is a schematic view showing a laminated structure in Example 1 of the present invention.

  The shaft is obtained by sequentially winding prepreg around an iron core called a mandrel, and pulling out the mandrel 1 after heat curing. A mandrel 1 is wound with a bias layer 2 formed and bonded to ± 45 °, a composite straight layer 5 having a weight portion 3 formed on the tip side and a light weight portion 4 formed on the butt side, and a straight layer 6 sequentially. .

A method of forming the composite straight layer 5 composed of the weight part 3 and the lightweight part 4 is as follows. First, the first requirement is that the light modulus 4 and the weight part 3 have substantially the same elastic modulus E expressed using the composite law of the following formula 1. The weight part 3 is obtained by mixing an additive of metal powder into the resin layer.
[Formula 1]

E: Prepreg modulus E _f: fiber tensile modulus E _m: Resin tensile modulus E _c: Additives Tensile modulus V _f: fiber volume content V _m: resin volume content V _c: Additives volume content

Here, “substantially the same” means a range in which the respective elastic moduli of the lightweight part 4 and the weight part 3 are not reversed by the metal powder or the like added to the weight part 3. For example, when fibers of prepregs TR350E125S and MR350E125S manufactured by Mitsubishi Rayon Co. are used, assuming that the tensile elastic modulus of TR350E125S is E _tr and the tensile elastic modulus of MR350E125S is E _mr , the following is obtained using Equation 1.

E _tr = 235 × 0.61 + 3 × 0.39 = 144.52 GPa
E _mr = 295 × 0.61 + 3 × 0.39 = 181.12 GPa
In the above example, the difference in tensile elastic modulus between the lightweight part 4 and the weight part 3 is 39.6 GPa. In this invention, when the difference of the lightweight part 4 and the weight part 3 is 36 GPa or less, it is set as substantially the same.

  In general, the grades of fibers are determined by their tensile elastic modulus, and are classified into high strength (low elasticity), medium elasticity, and high elasticity in ascending order, but TR350E125S is high strength (low elasticity) and MR350E125S is medium. Called elasticity.

<TR350E125S (Mitsubishi Rayon Co., Ltd.)>
E _f = 235 GPa
E _m: 3GPa
_Vf : 61%
V _m : 39%
E _c : 15 GPa
V _c : 0%

<MR350E125S (Mitsubishi Rayon Co., Ltd.)>
E _f = 295 GPa
E _m: 3GPa
_Vf : 61%
V _m : 39%
E _c : 15 GPa
V _c : 0%

  The above substantially identical conditions are specifically achieved by the combinations shown in Table 1.

As shown in Table 1, in order to make the lightweight part 4 and the weight part 3 closer to each other, it is preferable that each E _f is the same (composite straight layer candidate Nos. 4 to 6), and E _f and V _f are More preferably, they are the same. This is because the tensile modulus of the fiber has the greatest influence on the modulus of elasticity of the prepreg. In consideration of manufacturing tolerances, the difference in tensile elastic modulus between the lightweight part 4 and the weight part 3 is more preferably 10 GPa or less.

  The weight ratio between the lightweight part 4 and the weight part 3 is preferably 1: 1.5 or more, and more preferably 1: 2 or more. Usually, in order to change only the center of gravity without changing the weight, EI distribution, mandrel, etc., there is a method of increasing the number of windings at the front end of the bias layer and decreasing the number of windings at the rear end. However, the center of gravity movement amount in this case is less than 2% of the total length at the maximum. If the light weight part 4 and the weight part 3 have a weight difference of 1: 1.5 or more, this configuration can be adopted for the bias layer and the straight layer located 50% from the tip (see Example 3 described later). 1168 mm, about 55 g driver shaft) and can be adjusted over 2%. If it is 1: 2 or more, the range exceeding 2% can be adjusted by adopting this configuration only for the straight layer.

Examples of those satisfying 1: 1.5 or more include the following (see Table 2).
-Add metal particles (tungsten, gold, platinum, etc.) with a specific gravity of 18 or more to a volume ratio of 5% or more.

-Add metal particles (lead, silver, molybdenum, etc.) with a specific gravity of 10 or more to a volume ratio of 10% or more.

-Add metal particles having a specific gravity of 7 or more (copper, nickel, cobalt, iron, etc.) to a volume ratio of 15% or more.

Examples of those satisfying 1: 2 or more include the following (see Table 2).
・ Add metal particles with a specific gravity of 18 or more (tungsten, gold, platinum, etc.) at a volume ratio of 10% or more.

・ Add metal particles (lead, silver, molybdenum, etc.) with a specific gravity of 10 or more to a volume ratio of 15% or more.

  By forming 1: 2 or more, it is not necessary to arrange | position the weight part 3 in an innermost layer and an outermost layer, and the loss of the weight part 3 by peeling and grinding | polishing can be prevented.

  The lightweight part 4 and the weight part 3 are formed with substantially the same thickness. Here, “substantially the same” refers to a difference of 0.02 mm or less. This is not limited as long as the grades of the thickness of the prepreg that can be usually purchased can be determined to be the same level. Preferably it is 0.01 mm or less, More preferably, it is 0.005 mm or less which is within the range of a manufacturing error.

  The lightweight portion 4 and the weight portion 3 are integrated by fixing the end portions with a tape or the like before winding to obtain a composite straight layer 5. Further, the composite straight layer 5 does not necessarily have to be integrated as described above, and the light weight portion 4 may be wound after the weight portion 3 is wound. In this case, it is desirable to provide a gap of 1-5 mm between 3 and 4. When there is no gap, there is an overlapping portion between 3 and 4, causing a decrease in strength.

Hereinafter, specific examples of the prepreg that can be used in the golf club shaft of the present invention will be listed, but the invention is not limited thereto.
A: TR350C075S
(Tensile modulus 235 GPa, thickness 0.062 mm, manufactured by Mitsubishi Rayon Co., Ltd.)
B: TR350C100S
(Tensile modulus 235 GPa, thickness 0.083 mm, manufactured by Mitsubishi Rayon Co., Ltd.)
C: TR350C125S
(Tensile modulus 235 GPa, thickness 0.103 mm, manufactured by Mitsubishi Rayon Co., Ltd.)
D: TR350C150S
(Tensile modulus 235 GPa, thickness 0.145 mm, manufactured by Mitsubishi Rayon Co., Ltd.)
E: TR350C175S
(Tensile modulus 235 GPa, thickness 0.168 mm, manufactured by Mitsubishi Rayon Co., Ltd.)
F: TR350J050
(Tensile modulus 235 GPa, thickness 0.05 mm, manufactured by Mitsubishi Rayon Co., Ltd.)
G: TR350E100R
(Tensile modulus 235 GPa, thickness 0.095 mm, manufactured by Mitsubishi Rayon Co., Ltd.)
H: TR350E125S
(Tensile modulus 235 GPa, thickness 0.113 mm, manufactured by Mitsubishi Rayon Co., Ltd.)
I: TR350E150S
(Tensile modulus 235 GPa, thickness 0.156 mm, manufactured by Mitsubishi Rayon Co., Ltd.)
J: MRX350C075R
(Tensile elastic modulus 295 GPa, thickness 0.063 mm, manufactured by Mitsubishi Rayon Co., Ltd.)
K: MRX350C100R
(Tensile elastic modulus 295 GPa, thickness 0.084 mm, manufactured by Mitsubishi Rayon Co., Ltd.)
L: MRX350C125R
(Tensile elastic modulus 295 GPa, thickness 0.106 mm, manufactured by Mitsubishi Rayon Co., Ltd.)
M: MRX350C150S
(Tensile elastic modulus 295 GPa, thickness 0.127 mm, manufactured by Mitsubishi Rayon Co., Ltd.)
N: MR350K020S
(Tensile elastic modulus 295 GPa, thickness 0.020 mm, manufactured by Mitsubishi Rayon Co., Ltd.)
O: MR350J050S
(Tensile elastic modulus 295 GPa, thickness 0.050 mm, manufactured by Mitsubishi Rayon Co., Ltd.)
P: HRX35C075S
(Tensile elastic modulus 390 GPa, thickness 0.057 mm, manufactured by Mitsubishi Rayon Co., Ltd.)
Q: E1026C-10N
(Tensile elastic modulus: 98 GPa, thickness: 0.099 mm, manufactured by Nippon Graphite Fiber Co., Ltd.)
R: E052AA-10N
(Tensile modulus 49 GPa, thickness 0.109 mm, manufactured by Nippon Graphite Fiber Co., Ltd.)
S: Pre-preg for part by weight 3 (selected from Table 1 and Table 2 above)

  Examples of the material of the shaft include a fiber reinforced resin in which a matrix resin such as an epoxy resin is reinforced with fibers such as carbon fiber, glass fiber, aramid fiber, boron fiber, silicon carbide fiber, alumina fiber, and steel fiber. .

  Further, the shaft can be manufactured by, for example, sheet wrap molding, filament winding molding, inner shape or the like.

  The shape of the mandrel 1 wound around the prepreg is not particularly limited, but those having no stepped portion can exhibit the characteristics of the present technology.

  Table 3 below shows the shaft characteristics of Examples and Comparative Examples prepared by appropriately selecting the materials described above. The material, the number of layers, and the presence or absence of other reinforcing layers can be appropriately selected by the designer, and are not limited to the examples. In addition, the full length, weight, etc. of a shaft are not limited to an Example.

Hereinafter, specific examples will be described.
<Example 1>
In this example, as the composite straight layer, No. 1 in Table 1 was used. 1 was employed, and W5 in Table 2 was employed as the additive metal powder. As the prepreg for part by weight 3, fiber: 235 GPa made by Mitsubishi Rayon TR30, resin: # 350, additive: tungsten powder was used. As the prepreg for the lightweight part 4, fiber: 235GPa Mitsubishi Rayon TR30, resin: # 350 was used. The EI value of the manufactured shaft was measured by the following method.
<Measurement method of EI value>
The shaft is supported at two points with a fulcrum distance of 300 mm so that the measurement position is at the center, a load of 200 N is applied to the measurement position, and the bending deflection amount E at the distance L (mm) from the small diameter end to the measurement position (Mm) was measured, and the EI value was determined by the following formula (2).
[Formula 2]

（ただし、式中、Ｆは測定位置にかける荷重（Ｎ）であり、Ｄは支点間距離（ｍｍ）であある。）
その結果、ＥＩ分布が変わることなく重量分布のみ変化していることが分かった（表３参照）。

(Wherein, F is the load (N) applied to the measurement position, and D is the distance between support points (mm).)
As a result, it was found that only the weight distribution was changed without changing the EI distribution (see Table 3).

  The weight part 3 is not limited to this, and a fiber having a higher tensile elastic modulus may be used, and Vf may be reduced to match the elastic modulus of the light weight part 4. Even if Vf is increased by using a low fiber, the elastic modulus E of the lightweight part 4 and the heavy part 3 may be substantially the same as when the composite rule is used.

<Comparative Example 1>
In Comparative Example 1, a single straight layer 7 was used instead of the composite straight 5 in Example 1, and No. 1 in Table 1 was used. 1 was employed, and W10 in Table 2 was employed as the additive metal powder. The EI value was measured in the same manner as in Example 1. The results are shown in Table 3.

<Comparative Example 2>
A comparative example 2 is shown in FIG. Like patent document 1, the level | step-difference part 8 is formed in the front-end | tip of the mandrel 1, and the weight part 33 is provided in the level | step-difference part. It can be seen that the inner diameter has changed and that the EI has also changed (Table 1-Candidate 1, Table 2-Pb15).

<Comparative Example 3>
FIG. 4 shows Comparative Example 3. As in Patent Document 2, a weight portion 33 is provided inside the angle layer 2 and the single straight layer 7. It can be seen that the outer diameter has changed and the EI has changed (Table 1-Candidate 1, Table 2-W10).

<Example 2>
Example 2 is shown in FIG. The weight part 33 is used on the butt side. By forming in this way, the center of gravity can be arranged on the bat side. When assembling a long club, such a structure is advantageous when a shaft having a bat center of gravity is required (Table 1-Candidate 5 and Table 2-Pb15). Of course, the weight part 3 and the lightweight part 4 may be formed in an angle layer.

<Example 3>
Example 3 is shown in FIG. By using the composite angle layer 9, a larger change in weight distribution can be applied (Table 1-Candidate 4 and Table 2-W5).

<Example 4>
Example 4 is shown in FIG. Even if the composite straight layer is partially used as in this embodiment, the effect is exhibited. For this reason, a desired weight distribution can be obtained without changing the EI distribution. In the figure, it is arranged from the bat, but it may be arranged from the chip (Table 1-Candidate 6, Table 2-W10).

DESCRIPTION OF SYMBOLS 1 Mandrel 2 Bias layer 3 Weight part 4 Light weight part 5 Composite straight layer 6 Straight layer 7 Single straight layer 8 Step part 9 Composite angle layer

Claims (3)

In a golf club shaft formed by laminating a plurality of fiber reinforced composite material layers having an angle layer and a straight layer, at least one of the angle layer and / or the straight layer is a plurality of prepregs satisfying the following [1] to [3] formed of a composite material layer made of, by weight per unit area of below lightweight unit 4 and the following parts by weight 3 1: golf shafts, characterized in that not less than 1.5.
[1] It has a weight part 3 in which a lightweight part 4 and metal powder are mixed ,
[2] The thickness of the light unit 4 and the parts 3 are substantially the same,
[3] the lightweight portion 4 and the elastic modulus of the weight part 3 are substantially the same. The golf shaft according to claim 1, wherein the weight part 3 is any part of the chip side. The golf shaft according to claim 1, wherein the weight portion 3 is any part of the bat side.

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