JP3104034B2 - Wood golf club head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wood golf club head, and more particularly to a wood golf club head formed by injection molding by incorporating long fibers into a thermoplastic resin.

[0002]

2. Description of the Related Art Conventionally, as a method of manufacturing a golf club head mainly composed of fiber reinforced plastic, a compression molding method using a thermosetting resin and an injection molding method using a thermoplastic resin are known. Is being done. The molding method by the compression molding method is such that bulk molding compound (BMC), sheet molding compound (SMC), and prepreg are used alone or in combination as a material form, and carbon fibers, glass, and the like are used as reinforcing fibers. Fibers, aromatic polyamide fibers and the like are used.

[0003] The shape of the reinforcing fiber is bulk bulk
In the case of molding compounds, generally 1/5
Inch length to 1/2 inch length is used. In the case of a sheet molding compound, 1/2 inch length to 1 inch length cut fiber is used. In the case of prepreg, woven fabric of long fiber is used. Aya weave, satin weave, etc.) are used.

As the matrix resin, a thermosetting resin such as an epoxy resin, a polyester resin, a vinyl ester resin or the like is used, and the content of the fibers is generally 30 vol% to 40 vol% in the case of bulk molding compound.
vol%, in the case of a sheet molding compound, it is generally 30 vol% to 40 vol%. In the molding method by the injection molding method, a pellet-like material is used as a material form, and a carbon fiber, a glass fiber, an aromatic polyamide fiber or the like is used as a reinforcing fiber. As the shape of the reinforcing fiber, chopped fiber having a length of about 1/10 inch is used, and as the matrix resin, a thermoplastic resin such as ABS or polycarbonate is used. The fiber content is 5 to 18% by volume.

As described above, there are two conventional molding methods, a compression molding method and an injection molding method. As a current molding method, a golf club head is generally molded by a compression molding method.

[0006]

As described above, the reason why the compression molding method is used more frequently than the injection molding method is as follows. (a) .The injection molding method is superior to the compression molding method in terms of productivity and molding accuracy, but in this injection molding method, the material used is shorter in the reinforcing fiber length than in the compression molding method. ,
In addition, since the fiber content is low, the impact strength is low, and there is a problem in durability as a club head. (b) In the wall thickness design for ensuring the impact resistance of the club head and the like, a large amount of nests are apt to be generated in the wall thickness portion of about 10 mm or more, which causes the durability of the club head to decrease. Was.

For the above reasons, the compression molding method has been dominant in the past, but as described above, it is inferior to the injection molding method in terms of productivity and molding accuracy, and a shift to the injection molding method is desired. Despite this, the injection molding method could not become mainstream. The conventional thermoplastic resin for injection molding has a low impact strength, and has a problem in durability as a club head.

The present invention has been devised in view of such a conventional problem. By using an injection molding method, productivity and molding accuracy are improved, and nests are not generated even in a thick portion. It is an object of the present invention to provide a wood golf club head capable of manufacturing a club head having a durability equal to or higher than that obtained by a compression molding method.

[0009]

In order to achieve the above object, the present invention uses a reinforcing fiber having a length of about 1/4 inch to 1/2 inch and a fiber content of 20 vol% to 30 vol.
The gist is that a club head body is molded by injection molding using a thermoplastic resin containing l%.

[0010]

According to the present invention, a reinforcing fiber having a longer fiber length (approximately 1/4 inch to 1/2 inch long) than the conventional injection molding material is used, and By molding the club head main body by injection molding using a thermoplastic resin containing a fiber content of 20 vol% to 30 vol% in volume ratio, the club head main body has high productivity, good molding accuracy, and compression molding It is possible to manufacture a club head body having durability equal to or higher than the case.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a front view of a club head body 1 of a wood golf club formed by injection molding, and FIG.
FIG. 3 is a sectional view taken along the line AA of FIG.
FIG. 2 shows a bottom view of 2 in which the reinforcing fiber length is approximately 1/4 inch to 1/2 inch long, and the fiber content is 20% by volume.
The outer shell of a club head molded from a thermoplastic resin containing vol% to 30 vol%, 3 is a core body such as a syntactic foam filled in a hollow portion 4 of a club head body 1, 5.
Denotes a sole plate, and 6 denotes a shaft hole.

In an embodiment of the present invention, a reinforcing fiber having a longer fiber length (approximately 1/4) than a conventional material for injection molding.
Inch length to 1/2 inch length), and a club head body 1 is formed by injection molding using a thermoplastic resin having a fiber content of 20 vol% to 30 vol% in volume ratio as a raw material. 1 can produce a club head body 1 having high productivity, good molding accuracy, and durability equal to or higher than that of compression molding.

Next, a comparison is made between Examples 1 and 2 of the club head main body 1 of the present invention and Comparative Examples 1 and 2 of the club head by the conventional injection molding method and compression molding method. This will be described in a table.

[0014] As is clear from Table 1, when Examples 1 and 2 and Comparative Examples 1 and 2 are compared in terms of bending strength, tensile strength, and Izod impact strength, Example 1 of the present invention was obtained.
And as in Example 2, a reinforcing fiber having a long fiber length (approximately 1 /
Comparative example in which the club head body 1 is molded by injection molding using a thermoplastic resin having a fiber content of 20 vol% to 30 vol% in volume ratio of 4 inch to 1/2 inch long). Clearly higher strength could be obtained compared to the case of Comparative Example 1 and Comparative Example 2.

[0015] Injection molding machine used: mold clamping force 150 ton, injection capacity 25
0 cc, vertical type. Further, the molded club head body 1 was cut, and the occurrence of nests in the thick portions was examined. As a result, no nests were found in the thick portions exceeding 10 mm. Next, when a reinforcing fiber having a long fiber length (approximately 1/4 inch to 1/2 inch long) is used and a thermoplastic resin containing a fiber content of 20 vol% to 30 vol% by volume is molded as a material. The test results of the evaluation of hit ball durability will be described.

Wood golf club driver (count #)
After molding the club head of 1), a wood golf club driver is formed by a conventional method. By using a swing robot to hit a special leaded golf ball (weight 70g) repeatedly at a head speed of 40m / Sec by alternately hitting the toe and heel of the club head 100 times, and comparing the damage of the club head, The following hitting ball durability (index) could be evaluated. [Distribution of Fiber Length in Molded Product] The molded product of the club head body was baked and visually observed, and the original length (1/2 inch length) was maintained at 70% or more.

In the material of the present invention, it is not preferable to mix the internal release agent used in the conventional pellets for injection molding, and it is necessary to mix no release agent or to minimize it even if mixed. . The reason for this is that when assembling the club head into a golf club, the club shaft is inserted into the neck of the club head and fixed via an adhesive. This is because there is a risk of peeling. Also, in the case where the sole plate is fixed after being formed, it also causes trouble due to poor bonding.

[0018]

According to the present invention, there is provided a thermoplastic resin having a reinforcing fiber length of about 1/4 inch to 1/2 inch and a fiber content of 20 to 30 vol% by volume. Since the club head body is molded by injection molding using the material as a raw material, productivity and molding accuracy can be improved, and no nests occur in the thick part of the club head body, and when the conventional compression molding method is used. There is an effect that a club head having the same or higher durability can be manufactured.

[Brief description of the drawings]

FIG. 1 is a front view of a club head body formed by injection molding.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a bottom view of the club head main body.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Club head main body 2 Club head outer shell 3 Core body 4 Hollow part 5 Sole plate 6 Shaft hole

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) A63B 53/04 B29C 45/00

Claims (1)

(57) [Claims] 1. A wood golf club head formed by injection molding using a thermoplastic resin as a raw material, wherein a reinforcing fiber length is approximately 1/4 inch to 1/2 inch.
A wood golf club head characterized in that a club head body is molded by injection molding using a thermoplastic resin having a fiber content of 20 to 30 vol% in volume ratio.