JP2861447B2 - Tapered tubular body - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tapered tubular body made of a fiber-reinforced resin composite used for golf shafts and the like, and more particularly to a tubular body having improved torsional strength and / or reduced weight.

[0002]

2. Description of the Related Art The torsional strength of a tapered tubular body such as a golf shaft depends largely on a so-called oblique layer in which reinforcing fibers are obliquely oriented in the axial direction of the tubular body. More recently, the advent of highly elastic carbon fibers has made it possible to reduce the amount of carbon fibers used and to reduce the weight of the tubular body while maintaining a certain level of torsional rigidity.

[0003]

However, when the carbon fiber has a high modulus of elasticity, the strength as a composite material, particularly the compressive strength in the fiber direction, tends to decrease, so that the weight is reduced while maintaining the torsional strength of the shaft. Things have their own limits. Taking a golf shaft as an example, if the hitting position of the ball deviates greatly from the sweet spot of the club head on a shaft having insufficient torsional strength, an excessive torsional force is applied to the shaft, which may cause torsional breakage.

[0004]

The inventors of the present invention have made intensive studies to solve the above-mentioned problems. As a result, the golf shaft is usually tapered, and the torsional fracture of the shaft is caused by the tip of the shaft, that is, the torsion. What happens near the root of the head where the strength is the lowest, and even when the sweet spot is largely removed and the golf ball is hit, the torsional force applied to the shaft is almost constant regardless of the club and no extremely large force is generated Therefore, it has been noted that in order to improve the torsional rupture strength of the shaft, it is only necessary to reinforce the tip of the tubular body.

Focusing on the fact that a golf shaft is usually provided with a reinforcing layer at a tip portion having a small diameter, that is, a low torsional strength, in order to improve impact strength, the fiber orientation of this portion is adjusted with respect to the axial direction of the tubular body. By making the cross-section, the torsional rigidity can be increased in the cross section, and the stress applied to the high-elasticity carbon fibers used for the cross-section layer is partially borne by the cross-sectioned reinforcing layer. In other words, since the portion where the torsional strength of the shaft is smaller shifts to the larger diameter side by obliquely intersecting the reinforcing layer, the torsional breaking strength of the shaft can be dramatically increased, and the above problem is solved. That is, the present invention has been achieved. That is, an object of the present invention is to provide a shaft having a lighter weight and a torsion of the shaft below a certain level and having a necessary and sufficient strength. The object is a tapered tubular body made of a fiber-reinforced resin composite material, and the tubular body is reinforced on an oblique layer in which the reinforcing direction of the reinforcing fibers is oblique to the axial direction of the tubular body. In a tapered tubular body comprising at least two layers in which 0 ° layers in which the reinforcing direction of the fiber is the same as the axial direction of the tubular body are laminated, the reinforcing direction of the reinforcing fiber is set at the tip of the tubular body. A tapered tubular body characterized in that a reinforcing layer formed at an angle of at least 30 ° with respect to the axial direction is laminated on the oblique layer at the tip of the tubular body, and then a 0 ° layer is laminated. Easily achieved.

Hereinafter, the present invention will be described in detail. The reinforcing fiber used in the present invention is not particularly limited as long as it is a fiber having generally high characteristics such as aramid fiber and carbon fiber.
The form of the reinforcing fibers may be a unidirectional material aligned in one direction or a woven material. The ratio of the number of graticules of the woven material and the angle formed by the graticules are not particularly limited, but are usually 1: 1 and 90 °.

The resin to be used is not particularly limited as long as it can be used for ordinary fiber-reinforced resin composite materials, and specific examples thereof include epoxy resins. The tapered tubular body of the present invention is made of a fiber reinforced resin composite material, and the tubular body is reinforced on an oblique layer in which the reinforcing direction of the reinforcing fibers is oblique to the axial direction of the tubular body. It is composed of at least two layers in which 0 ° layers in which the reinforcing direction of the fibers is the same as the axial direction of the tubular body are laminated.

Here, the oblique layer is provided for the purpose of mainly imparting torsional characteristics to improve the torsional characteristics of a tubular body, for example, a shaft, in particular, to improve the torsional strength. In the present invention, in addition to simply providing such an oblique layer, in order to improve the impact strength of the distal end having a small diameter of the tubular body, between the oblique layer at the distal end of the tubular body and the 0 ° layer. It is characterized in that a reinforcing layer is provided.

The reinforcing layer is formed so that the reinforcing fibers are reinforced at an angle of at least 30 ° with respect to the axial direction of the tubular body in order to improve the torsional strength. If it is less than this range, it is difficult to obtain sufficient torsional strength and rigidity. In the present invention, the term “oblique” refers to a unidirectional reinforcing fiber reinforced resin body (prepreg body) such that the reinforcing fibers are reinforced in the opposite direction with respect to the tubular body axis direction. This means that the cut prepreg bodies forming a pair are overlapped and wound so that the reinforcing direction of the reinforcing fibers intersects the axial direction of the tubular body. For example, the fact that the reinforcing direction of the reinforcing fibers is oblique to 30 ° with respect to the axial direction of the tubular body means that
The direction of the reinforcing fiber of the prepreg body, that is, the reinforcing direction is + 30 ° and -30 °, respectively, so as to be paired,
This may be wound and formed.

In the case of a woven material, it is preferable that the direction of the warp is wound around ± 45 ° with respect to the axial direction of the shaft. The cutting shape of the prepreg or woven material forming a pair, the way of overlapping, the reinforcing fiber, resin and the amount of the prepreg or woven material are not limited, but the length to be reinforced is originally determined by the reinforcing layer. Even in the case where it does not exist, it is preferable to reinforce from the tip of the tapered tubular body to the cross-sectional position having the required torsional strength, and it is desirable that the length be equal to or less than half of the entire length. The number of winding plies is determined so as to satisfy a predetermined torsional strength. It is preferable from the viewpoint of workability that the pair of prepreg bodies be wound while being shifted by half the circumference of the cored bar.

The reinforcing layer of the present invention is inclined at least 30 ° with respect to the axial direction of the tubular body, but if it is smaller than 30 °, it is difficult to exhibit sufficient characteristics in terms of reinforcing torsion characteristics. Yes, not preferred, usually 30-45 °,
Preferably, the angle should be 35 to 45 °. Although the reinforcing fibers used in the reinforcing layer does not necessarily need to be high modulus, preferably tensile modulus 30t / mm ² or more, more preferably better to use one of 35~70t / mm ^2, the tubular body When twisted with a predetermined force, the amount and orientation angle of the prepreg used in the reinforcing layer may be determined so that the strain generated in the oblique layer is not more than the allowable strain of the high-performance fiber. However, when the elastic modulus of the reinforcing fiber is extremely low compared to the elasticity of the oblique layer, and when there is a restriction that the tip diameter is almost constant like a golf shaft, the torsional rigidity of the oblique reinforcing layer is reduced. The effect of improving the torsional strength of the shaft cannot be expected because it is small, which is not preferable.

A heat-shrinkable tape is wrapped around a tubular laminate obtained by winding the oblique reinforcing layer determined by such a method around the tip of the tubular body in a desired lamination order, and is necessary for curing the matrix resin in a heating furnace. After curing at an appropriate temperature, the core is removed and the desired tubular body is obtained.

[0013]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist.

Examples 1 to 3 and Comparative Examples 1 to 4 The high elasticity of a pitch-based carbon fiber "Dialead" K137 carbon fiber (elastic modulus 65 ton / mm ² ) as an oblique layer of a golf shaft was manufactured by Mitsubishi Kasei Corporation. A unidirectional drawing prepreg “HYEJ16M65D” (manufactured by Kasei Fiberlight Co., Ltd.) using yarn as a reinforcing fiber was used, and a layer in which the fiber drawing direction was aligned with the shaft axis direction (hereinafter referred to as a 0 ° layer). prepreg "HYEJ15" align carbon fiber pulling elastic modulus 23t / mm ² in (Chemical fiber light Co.). prepreg aligned carbon fibers pulling elastic modulus 23t / mm ² as a reinforcing layer using the "HYEJ12" (ibid)
And a carbon fiber aligned prepreg “HYEJ14M40” having an elastic modulus of 40 t / mm ² (same as above) and an elastic modulus of 30 t / mm ²
mm ² carbon prepreg “HYEJ14M3”
0. The prepreg “H” was used as the shaft oblique layer.
Further, the prepreg body of +40 degrees and -40 degrees is added to the entire length of the shaft so that the direction of the drawn fiber of YEJ16M65D "is +40 degrees and -40 degrees with respect to the center axis of the cored bar.
Two pairs of prepreg bodies cut into a trapezoidal shape so as to form a ply are overlapped by being shifted by half the circumference of the core metal, and wound as a prepreg laminated body around the core metal. The prepreg was cut into a triangular shape so that the fiber direction was +40 degrees and −40 degrees with respect to the central axis of the cored bar, and it was cut and wound into a triangular shape so that the width and length of each ply were 3 ply and 275 mm at the tip of the shaft. Further, a prepreg “HYEJ15” as a 0-degree layer was cut into a trapezoid so as to have three plies over the entire length of the shaft, wound, and formed by a conventional method.

As a comparative example, the oblique layer and the 0-degree layer were made exactly the same as those of the embodiment, and only the orientation direction of the reinforcing fibers of the reinforcing layer was changed to obtain a shaft having normal orientation directions of 0 degree and ± 20 degrees. It was molded and subjected to a test. The shaft weight, torsion angle, torsional strength, and impact strength of these shafts were measured and compared. Table 1 shows the relationship between the lamination structure and the shaft characteristics.

Example 4 Instead of the prepreg “HYEJ12” used in Example 1, a woven prepreg “HMF322 / 48AIC” was used, and the direction of the woven fabric weft system was ± 4 with respect to the mandrel axis.
A shaft was formed and subjected to a test in the same manner as in Example 1 except that the shaft was wound at 5 °. Table 1 shows the results. In addition, workability during winding was also improved due to the flexibility of the woven prepreg.

[0017]

[Table 1]

[0018]

According to the present invention, since the reinforcing layer for orienting the reinforcing fibers in the axial direction of the tubular body is obliquely arranged in the axial direction, the reinforcing member can be reinforced without substantially changing the weight of the tapered tubular body. When a force is applied, it is possible to prevent torsional breakage that usually occurs in a small diameter portion. Further, according to the present invention, since the torsional rigidity is increased with respect to the tip of the tubular body having a large torsion, the torsion angle of the shaft, which is an important characteristic of the shaft, can be reduced.
^{Use of two} or more can greatly reduce the torsion angle.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-193686 (JP, A) JP-A-2-291879 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) A63B 53/10 B29C 70/06 B29K 105: 10 B29L 31:52

Claims (1)

(57) [Claims] 1. A tapered tubular body made of a fiber-reinforced resin composite material, wherein the tubular body is reinforced on an oblique layer in which a reinforcing direction of reinforcing fibers is oblique to an axial direction of the tubular body. In a tapered tubular body comprising at least two layers in which 0 ° layers in which the reinforcing direction of the fiber is the same as the axial direction of the tubular body are laminated, the reinforcing direction of the reinforcing fiber is set at the tip of the tubular body. A reinforcing layer formed at an angle of at least 30 ° with respect to the axial direction of the tubular body, on the oblique layer at the tip of the tubular body, and then a 0 ° layer is stacked.