JPH0592053A - Wood golf club head - Google Patents

Abstract

PURPOSE:To improve durability, productivity and molding accuracy and to prevent the generation of blow holes in a thick part by using a thermoplastic resin for which specific reinforcing fiber lengths are used and which contains the fibers at a specific content as a blank material and molding a club head body by injection molding. CONSTITUTION:An outside shell 2 of the club head is molded by injection molding using the thermoplastic resin for which about 1/4 to 1/2 inch long reinforcing fiber lengths are used and which contains the fibers at 20 to 30vol.% in a volumetric rate as the blank material. A core material 3 is formed by packing a syntactic foam, etc., into a hollow part 4 of the club head body 1 and providing a sole plate 5 and a shaft hole. The club head body 1 having the durability equal to and higher than the durability of the club head body formed by compression molding is produced with high productivity and high molding accuracy in this way. The generation of the blow holes in the thick parts is obviated.

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 in which long fibers are contained in a thermoplastic resin and integrally molded by injection molding.

[0002]

2. Description of the Related Art Conventionally, as a method for manufacturing a golf club head mainly made of fiber reinforced plastic, there are a compression molding method in which a thermosetting resin is used and an injection molding method in which a thermoplastic resin is used. Has been done. The molding method by the compression molding method is used as a material form, such as bulk molding compound (BMC), sheet molding compound (SMC), prepreg, or a combination thereof, and the reinforcing fiber is carbon fiber or glass. Fibers, aromatic polyamide fibers, etc. are used.

The shape of the reinforcing fiber is bulk or
Generally 1/5 for molding compounds
Inch length to 1/2 inch length is used, and in case of sheet molding compound, 1/2 inch length to 1 inch length cut fiber is used, and in the case of prepreg, long fiber woven fabric ( Aya weave, satin weave, etc.) are used.

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

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

[0006]

As described above, the reasons why the compression molding method is more frequently used than the injection molding method are as follows. (a) .The injection molding method is superior to the compression molding method in terms of productivity and molding accuracy. However, in this injection molding method, the length of the reinforcing fiber is shorter than that in the case of the compression molding method. ,
Moreover, since the fiber content is low, the impact strength is weak and there is a problem in durability as a club head. (b). In designing the thickness of the club head in order to secure the impact resistance, etc., a large number of cavities are likely to occur in a thick portion of about 10 mm or more, which causes the durability of the club head to deteriorate. It was

For this reason, the compression molding method has been the mainstream 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. However, the injection molding method could not become the 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 conventional problems. By using an injection molding method, productivity and molding accuracy are improved, and no cavities are formed in the thick portion. It is an object of the present invention to provide a wood golf club head capable of producing a club head having durability equal to or higher than that obtained by the compression molding method.

[0009]

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

[0010]

The present invention is constructed as described above and uses reinforcing fibers (approximately 1/4 inch length to 1/2 inch length) having a longer fiber length than the conventional injection molding material, 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 that of the case.

[0011]

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

In the embodiment of the present invention, as compared with the conventional material for injection molding, the reinforcing fiber having a long fiber length (approximately 1/4) is used.
(Inch length to 1/2 inch length), and the club head body 1 is formed by injection molding using a thermoplastic resin having a fiber content of 20 vol% to 30 vol% as a volume ratio. No. 1 has high productivity, good molding accuracy, and can manufacture a club head body 1 having durability equal to or higher than that of compression molding.

Next, Examples 1 and 2 of the club head body 1 of the present invention and Comparative Examples 1 and 2 of the conventional injection molding and compression molding club heads will be compared and the following will be described. This will be explained in the table.

[0014] As is clear from Table 1, when Example 1 and Example 2 are compared with Comparative Example 1 and Comparative Example 2 in terms of bending strength, tensile strength and Izod impact strength, Example 1 of the present invention
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% as a volume ratio. It was possible to obtain a clearly higher strength than in the cases of 1 and Comparative Example 2.

[0015] Injection molding machine used: mold clamping force 150 ton, injection capacity 25
0 cc, vertical type. In addition, as a result of cutting the molded club head main body 1 and examining the generation state of cavities in the thick portion, no cavities were observed in the thick portion exceeding 10 mm. Next, when a reinforcing fiber having a long fiber length (approximately 1/4 inch length to 1/2 inch length) is used, and a thermoplastic resin containing a fiber content rate of 20 vol% to 30 vol% is used as a material The evaluation test results of the hit ball durability will be described.

Wood Golf Club Driver (Count #
After molding the club head of 1), it is used as a driver for a wood golf club by a conventional method. Using a swing robot, a lead-containing special golf ball (weight 70g) was alternately hit with a club head toe and heel 100 strokes at a head speed of 40m / Sec. By comparing the damage of the club head, The following hit ball durability (index) could be evaluated. [Distribution of Fiber Length in Molded Product] At the level of visually observing the molded product of the club head main body, 70% or more of the original length (1/2 inch length) was retained.

It should be noted that the material of the present invention does not preferably contain an internal mold release agent used in conventional injection molding pellets, and it is necessary to mix no mold release agent at all or to keep it to a minimum. .. The reason for this is that when the club head is assembled into a golf club, the club shaft is inserted into the neck portion of the club head and fixed with an adhesive. This is because there is a risk of peeling. Also, when the sole plate is fixed after being molded, it causes a trouble due to defective adhesion.

[0018]

As described above, the present invention is a thermoplastic resin in which the reinforcing fiber length is approximately 1/4 inch length to 1/2 inch length and the fiber content is 20 vol% to 30 vol% in volume ratio. Since the club head main body is molded by injection molding using as a material, productivity and molding accuracy can be improved, and no cavities occur in the thick portion of the club head main body. There is an effect that a club head having durability equal to or higher than that can be manufactured.

[Brief description of 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 body.

[Explanation of symbols]

1 Club Head Main Body 2 Club Head Outer Shell 3 Core 4 Hollow 5 Sole Plate 6 Shaft Hole

Claims (1)

[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 length to 1/2 inch length,
A wood golf club head characterized in that a club head body is formed by injection molding using a thermoplastic resin having a fiber content of 20 vol% to 30 vol% as a volume ratio.