JPH11262546A - Racket frame - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a light racket with good flexibility on hitting a ball and excellent strength by forming at least a part of the outer shell layer constituting the racket frame made of a fiber-reinforced resin by a fiber-reinforced resin reinforced by carbon fiber with specific tensile elasticity. SOLUTION: In the racket frame comprising a ball hitting part formed of a gut strings network face, a grip part and a shaft part to connect the ball hitting part and the grip part, all parts of ball hitting part, shaft part, and grip part are formed of fiber reinforced resin reinforced by carbon fiber with 230 GPa of tensile elasticity and carbon fiber with 54 GPa of tensile elasticity. That is, the outer layer 6 made of fiber reinforced resin placed on the periphery of a core material 5 is formed by sandwiching a fiber reinforced resin layer 8 reinforced by a carbon fiber with 54 GPa of tensile elasticity between two fiber reinforced layers 7 reinforced by carbon fiber with 230 GPa of tensile elasticity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a racket frame molded from a fiber reinforced resin.

[0002]

2. Description of the Related Art Conventionally, racket frames have been formed using materials such as wood and metal. However, at present, various characteristics such as toughness, rigidity and repulsion required for racket frames are satisfied. In addition, since there is a large degree of freedom in designing such that a required shape can be easily obtained, a racket frame made of fiber reinforced resin has come to occupy the mainstream. Usually, this type of racket frame is, as shown in FIG.
It has a structure comprising a solid or hollow core material 13 and an outer shell layer 14 made of a fiber-reinforced resin disposed around the core material 13, and the outer shell layer 14 generally has a tensile modulus of 230 to
It is formed by appropriately laminating a reinforcing fiber layer 15 mainly composed of 400 GPa carbon fiber or glass fiber.

[0003]

However, such a racket frame, particularly a racket frame formed using conventional carbon fibers, has the characteristics of being lightweight and having excellent specific strength. Due to its high rigidity, it is difficult to express the necessity as a racket frame, and there is a problem that the resilience and feeling at the time of hitting the ball cannot be satisfied. This drawback can be alleviated to some extent by using glass fiber having a lower tensile modulus than the above-mentioned carbon fiber, but glass fiber has a drawback that its specific strength is inferior to carbon fiber, and it is practically used as a racket frame. In order to ensure sufficient strength, a large amount of glass fiber must be used, and since the specific gravity of the glass fiber itself is large, the weight and balance of the racket frame are significantly increased, and the feel when hitting the ball is increased. There was a problem that had an adverse effect.

In view of the above-mentioned drawbacks of the prior art, an object of the present invention is to provide a racket frame which is not only excellent in hitting at the time of hitting a ball but also is lightweight and has excellent strength.

[0005]

In order to achieve the above object, the present invention has the following arrangement. That is, in the racket frame according to claim 1 of the present invention, at least a part of the outer shell layer constituting the racket frame made of a fiber-reinforced resin is made of a fiber-reinforced resin having a tensile modulus of elasticity of 60 GPa or less. The racket frame is characterized by being constituted.

A racket frame according to a second aspect is characterized in that the carbon fiber having a tensile modulus of 60 GPa or less is used in combination with a reinforcing fiber having a tensile modulus of 70 to 400 GPa. , Claim 3
The racket frame according to item 1, wherein the tensile elastic modulus is 60.
A carbon fiber of GPa or less is used at a position where a shaft portion of a racket frame is formed.

Thus, in the racket frame of the present invention, all parts of the racket frame, that is, all parts constituting the hitting part, the shaft part, and the grip part of the racket frame have a tensile modulus of elasticity of 60 GPa or less. The racket frame is composed of a carbon fiber having a tensile modulus of 60 GPa or less and a tensile modulus of 70 to 40.
If the racket frame is made of fiber reinforced resin reinforced with 0 GPa reinforcing fiber, and only the shaft portion of the racket frame has a tensile modulus of elasticity of only carbon fiber reinforced with carbon fiber of 60 GPa or less, or has a tensile elasticity. Carbon fiber with a modulus of 60 GPa or less and a tensile modulus of 70 to 40
It is composed of a fiber reinforced resin reinforced with a reinforcing fiber of 0 GPa, and the other parts have a tensile elasticity of 70 to 400 GP.
It may be composed of the reinforcing fiber a.

In particular, when the entire racket frame is made of a fiber-reinforced resin reinforced only with carbon fibers having a tensile elasticity of 60 GPa or less, a conventional carbon fiber (having a tensile elasticity of 230 GPa or less) is used. Compared to a racket frame made of fiber reinforced resin reinforced with carbon fiber, the weight and strength are almost the same, but the amount of deflection can be increased by about 30%, so that soft tennis (also referred to as soft tennis) This is suitable for obtaining a racket frame requiring a relatively large bending, such as a racket frame for ()). In the case where only the shaft portion of the racket frame is made of a fiber reinforced resin having a tensile elasticity of 60 GPa or less reinforced with carbon fiber, the waist portion of the racket that needs appropriate bending is sufficiently unnecessary. A racket having a high strength can be realized.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to preferred embodiments described in detail with reference to the drawings. FIG. 1 is a front view of a racket frame of the present embodiment, FIG. 2 is an enlarged end view of the racket frame taken along the line AA, and FIG. 3 is an explanatory view showing a method of manufacturing the racket frame of the present embodiment. FIG. 4 is an enlarged end view of a racket frame according to another embodiment. As shown in FIG. 1, the racket frame 1 of the present embodiment has a hitting portion 2 on which a gut is stretched to form a net surface.
And an open throat shape composed of two left and right shaft portions 3 connecting the hitting portion 2 and the grip portion 4, and the entire racket frame 1, that is, the hitting portion 2 and the shaft portion 3 and all parts of the grip portion 4 are made of a fiber reinforced resin reinforced with carbon fibers having a tensile modulus of 230 GPa and carbon fibers having a tensile modulus of 54 GPa.

That is, the racket frame 1 of the present embodiment
As shown in FIG. 2, the outer shell layer 6 made of fiber reinforced resin disposed around the core material 5 has a tensile modulus of 230 GPa.
A fiber reinforced resin layer 7 reinforced with carbon fiber and a fiber reinforced resin layer 8 reinforced with carbon fiber having a tensile modulus of 54 GPa, wherein the fiber reinforced resin layer 8 is One layer is interposed between the seven layers.

As shown in FIG. 3, the racket frame 1 having the above-described structure has a tensile elasticity of 230 GPa around a nylon tube 9 formed in a length necessary for molding the racket frame 1 in advance. Prepregs 10a, 10b, 10c, 10d, 1 using carbon fibers as reinforcing fibers
0e and a prepreg 11 having carbon fiber having a tensile modulus of 54 GPa as a reinforcing fiber are laminated and wound to form a racket frame molded body 12, and then the racket frame molded body 12 is placed in a mold. After the mold is clamped, the tube 9 is formed by injecting compressed air into the tube 9 to heat and cure the tube 9 while expanding the tube.

The physical properties of the molded racket frame 1 of the present embodiment were subjected to a frame bending test, and the breaking strength and the amount of deflection were measured, and compared with those of the conventional racket frame. As a conventional product, one prepared by replacing the prepreg 11 with the prepreg 10 was prepared. As a result, the racket frame 1 obtained by the present example had the breaking strength not much different from that of the conventional product, but the amount of flexure was about 20% larger than that of the conventional product, and the rigidity was reduced without lowering the strength. The racket frame was completed.

In the above embodiment, the tensile modulus is 60 G
Although the configuration is such that the carbon fiber of Pa or less is used for the entire portion of the racket frame 1, the carbon fiber can be locally used in any portion where the racket frame is desired to bend. In this case, it is possible to adopt a configuration in which only the portion where bending is desired is constituted only by the carbon fiber, or a portion of the reinforcing fibers constituting the portion is replaced with the carbon fiber. Further, in addition to the configuration in which the carbon fibers are arranged around the entire outer shell layer 6 as in the above-described embodiment, the configuration is such that the carbon fibers are partially arranged in the outer shell layer 6 as shown in FIG. You can also.

[0014]

As described above, according to the present invention, at least a part of the outer shell layer of the racket frame has a tensile modulus of 60.
Because it is composed of a fiber reinforced resin reinforced with carbon fibers having excellent specific strength and low elasticity of GPa or less,
The required strength of the racket frame can be sufficiently secured, and the racket frame can be easily bent. Moreover, since the carbon fiber has a lower specific gravity than glass fiber, it is possible to provide a lightweight racket frame that can be easily swinged out without increasing the weight of the racket frame.

[Brief description of the drawings]

FIG. 1 is a front view of a racket frame according to the present embodiment.

FIG. 2 is an enlarged end view taken along the line AA of the racket frame of the embodiment.

FIG. 3 is an explanatory view of a method of manufacturing the racket frame of the embodiment.

FIG. 4 shows a racket frame A according to another embodiment.
-A line part enlarged end view.

FIG. 5 is an explanatory diagram of a configuration of a conventional racket frame.

[Explanation of symbols]

 Reference Signs List 1 racket frame 2 hitting part 3 shaft part 4 grip part 5 core material 6 outer shell layer 7 fiber reinforced resin layer 8 fiber reinforced resin layer 9 tube 10a prepreg 10b prepreg 10c prepreg 10d prepreg 10e prepreg 11 prepreg 12 racket frame molded body 13 core Material 14 Outer shell layer 15 Reinforcing fiber layer

Claims (3)

[Claims] At least a part of a shell layer constituting a racket frame made of fiber reinforced resin has a tensile modulus of elasticity of 60.
A racket frame comprising a fiber reinforced resin reinforced by a carbon fiber of GPa or less. 2. The racket frame according to claim 1, wherein the carbon fiber having a tensile modulus of 60 GPa or less is used in combination with a reinforcing fiber having a tensile modulus of 70 to 400 GPa. 3. The racket frame according to claim 1, wherein the carbon fiber having a tensile modulus of elasticity of 60 GPa or less is used at a position where a shaft portion of the racket frame is formed.