JPH0489071A - Wood club head for golf - Google Patents

Abstract

PURPOSE:To increase the flying distance of a ball by forming the face, back face and sole face of a head main body into a shell structure made of high- rigidity fiber-reinforced plastics(FRP), and forming the crown face with the FRP having the rigidity lower than that of the face, back face and sole face. CONSTITUTION:Most of a head main body 1, i.e., the face 2, back face 3, sole face 4, toe side face 6, heel side face 7 and hosel section 8 except the crown face 5, is formed into a shell structure filled with a filler material 12 such as foamed synthetic resin in a core section made of a high-rigidity FRP 11, and the crown face 5 is made of a low-rigidity FRP 13. When a ball is driven with a golf club with this head structure, the initial driving angle is made large, a large realistic ballistic locus with little flying-up is obtained, thereby the flying distance of the ball can be extended.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] This invention relates to a golf wood club head consisting of a head outer shell mainly made of fiber reinforced plastics (hereinafter abbreviated as FRP). By making the rigidity of the surface lower than that of the other face surfaces, back surface, and sole surface, the flight distance of the ball is increased.

``Prior Art'' Traditionally, this divine golf club head, like a wood club made of wood such as persimmon,
The entire head has a homogeneous and continuous solid structure, or the outer shell structure is hollow or has a core filled with a soft material such as foam, like a metal or FRP wood club.

In a wood club head with such a conventional structure,
The face of the head body (the front two ball-hitting surfaces facing the ball-hitting direction), the sole surface (bottom surface), the back surface (the rear surface facing the ball-hitting direction), the crown surface (-H surface), and the toe side (orthogonal to the ball-hitting direction). The heel side surface (the front surface facing the ball) and the heel side surface (the rear surface facing perpendicularly to the ball hitting direction) are continuously formed integrally, and in particular, the face surface has a predetermined loft angle depending on the club count, In order to improve the directionality due to the spin effect on the ball, a plurality of horizontal grooves are usually provided.

Furthermore, in order to increase the repulsive force against the ball when hitting the ball, some golf clubs have a configuration in which a separate hitting plate is attached to the sweet spot (point of impact) on the face surface.

[Problems to be Solved by the Invention] However, in the structure of the conventional golf wood club head described above, the face surface is set at a specific loft angle depending on the club count, so the larger the loft angle, the more the ball Although the advantageous hitting angle increases in order to extend the flight distance of the ball, the backspin applied to the ball also increases and the run (rolling of the ball after landing) decreases, which has the opposite effect on extending the flight distance of the ball. In particular, when the ball is hit by a headwind, the ball tends to fly up a lot, making it impossible to expect the ball to fly as far as the loft angle depending on the club count.

Therefore, in order to eliminate such defects in the golf club head with the conventional structure, the applicant first developed the 1999 wood club head.
An invention described in Japanese Patent Application No. 1-263647 filed on October 9, 2007 (hereinafter referred to as the "prior invention") has been proposed.

According to this prior invention, by configuring the crown surface of the head body made of FRP outer shell structure separately from thin sheet metal, it is possible to increase the flight distance of the ball even if the loft angle of the face surface is fixed. It is something that we have devised to make it possible.

[Objective of the Invention] The object of the present invention is to provide a wood club head for golf that is capable of further increasing the flight distance of the ball by improving the head outer shell structure of the earlier invention described above. It is in.

[Means to achieve the purpose] In order to achieve the above-mentioned object, this invention.

At least the face, back and sole surfaces of the head body have an outer shell structure made of highly rigid FRP, and the crown surface is formed of FRP which has a relatively lower rigidity than the face, back and sole surfaces. The structure is as follows.

[Components of the invention Hereinafter, the configuration of the present invention will be explained based on the drawings.

As shown in FIG. 3, reference numeral 1 in the figure is the head body of the golf wood club according to the present invention.

This head body 1 is composed of a face surface 2, a back surface 3, a sole surface 4, a crown surface 5, a toe surface 6, a heel surface 7, and a hosel portion 8 to which a shaft S is attached. Other aspects except 3.5.6.
7 has a curved surface with a large curvature of 1, and the hosel portion 8 has a substantially cylindrical shape.

As shown in FIGS. 1 and 2, the head body 1 includes a face surface 2 other than the crown surface 5, a back surface 3, a sole surface 4. The main parts of the toe side surface 6, heel side surface 7, and hosel part 8 are made of an outer shell structure in which a core made of highly rigid FRPII is filled with a filler 12 such as foamed synthetic resin. 5 is low rigidity FR
It is composed of P13.

Note that 9 in the figure is a face plate made of hardened FRP, ceramics, etc., embedded in the face surface 2 of the head main body 1.

That is, the highly rigid FRPII constituting the main body part of the head body 1 may be used as a weave or knitting form of reinforcing fibers, such as roving, plain weave cloth, twill cloth, bias cloth, etc., or in combination of two or more of them. death,
In addition, the types of fiber materials used include carbon, glass, silica, boron, aromatic polyamide, etc.
A material for FRP molding, in which the reinforcing fibers are suitably impregnated with a matrix synthetic resin such as epoxy resin, unsaturated polyester resin, or epoxy acrylate resin. It is obtained by hardening and molding the material by heat and pressure, and its elastic modulus is in the range of 100-250 GPa, preferably 150-250 GPa, and its thickness is set in the range of 4 to 12 mm, although it varies on each side. This is what is being done.

On the other hand, the low-rigidity FRPl 3 constituting the crown surface 5 of the head body 1 uses polyester fibers such as polyethylene terephthalate or organic fibers such as aliphatic polyamide or polyvinyl acetate as reinforcing fibers,
It is obtained by hardening and molding raw material for FRP molding by hot pressure, in which such fibers are suitably impregnated with a matrix synthetic resin such as epoxy resin, unsaturated polyester resin, or epoxy acrylate resin.
Its elastic modulus is 2-10 GPa, preferably 3-5
It is set within the range of GPa.

Furthermore, a high-rigidity FRPl2 as the main body part of the head body 1 and a low-rigidity FRPl as the crown surface 5 are also included.
At the boundary with 3, as shown in Figure 3, for example,
Both types of FRP materials are mixed together.

Next, the means for molding the golf club head according to the present invention by injection molding will be explained based on FIGS. 4 to 8.

A core 23 formed in advance from a low melting point alloy that can be eluted to approximately approximate the shape of the head core is placed in a cavity of a mold 20 consisting of a pair of left and right split molds 21 and 22. At this time, the temperature of the mold 20 is preferably set higher than the curing temperature of the uncured synthetic resin of the raw material for FRP molding, and lower than the melting temperature of the core 23.

The core 23 has a holding hole 24 in its center that extends upward from the bottom side corresponding to the head sole side. By inserting the tip opening 25a of the feed tube 25 for feeding green material for FRP molding, the core 23 is clamped into the mold hole 20a in the mold clamping state through the feed tube 25. It is positioned and held so that a gap A corresponding to the thickness distribution of the head shell is formed between the outer peripheral surface and the inner peripheral wall surface of the cavity of the mold 20 (see FIG. 4).

At this time, a portion of the mold 20 or the core 23 corresponding to the head ball hitting surface, back surface, sole surface, etc.
A face plate 9 made of hardened FRP, ceramics, etc., and weight members, etc., as needed, are arranged in a temporarily fixed state.

In this state, using the feed tube 25 of the raw material for FRP molding protruding outside the mold 20 as a cylinder, the other face surface of the head body 1 except the crown surface 5 is pressed by the piston body 26. 2. First FRP molding raw material 3 for molding the back surface 3, sole surface 4, toe side surface 6, heel side surface 7, and the main body of the head outer shell of the hosel portion 8.
1 is introduced into the gap A (see FIG. 5).

Next, after feeding the first FRP molding raw material 31, the second FRP molding raw material 32 to be molded into the crown surface 5 of the head body 1 is moved into the gap A by the pushing action of the piston body 26. This is done by supplying the material to a container and subjecting it to hardening and molding (see Fig. 6).

After the head outer shell molded body 40 is cured and molded, the head outer shell molded body 40 is taken out from the mold 20 and placed in a high-temperature air chamber (not shown) to raise the temperature, melting the core 23 and forming the mold. It is eluted to the outside through the hole 20a.

Furthermore, after the core 23 is eluted and removed, if necessary, the core is filled through the hole 41 formed in the sole surface equivalent part 40a of the head outer shell molded body 40 by pulling out and removing the feeding cylinder 25. The head body 1 as shown in FIG. 1 is formed by filling an unfoamed synthetic resin liquid 42 as a material and foaming and hardening it.

[Function] Next, the action of the golf club head of the present invention having the above-mentioned configuration due to its behavior when hitting a ball will be explained in detail with reference to FIGS. 7 and 8.

When ball B is hit with the golf club having the head structure according to the present invention, as shown by the solid line in FIG. As a result, the flight distance of the ball B can be greatly extended, and since the backspin of the ball B is small after falling onto the ground G, a large run can be obtained. Note that the dotted line shown in FIG. 9 indicates the trajectory of the trajectory of the head of the conventional structure.

Such behavior of the ball B can be understood from the measurement results of how backspin is applied to the ball B when the ball is hit, which will be described below.

That is, first, so that the rotational state of ball B is known,
Draw several lines on the circumferential surface of ball B to serve as landmarks, like longitude lines on a globe.

Then, by illuminating this ball B with a strobe that flashes continuously at a time interval of, for example, 2 milliseconds, and photographing the ball B at the time of hitting the ball, it is possible to take a photograph of the ball B immediately after the ball B starts flying due to the impact of the club head. The rotational speed of the ball can be quantitatively measured.

According to these measurement results, the ball B is attached to the head body 1.
Flight distance 200 m immediately after leaving face 2 of
The rotation angle of the ball during the movement of m was 29.0° in the conventional head made entirely of wood, but was reduced to 21.5° in the head of the present invention.

In this case, the direction of rotation of the ball B is such that the moving speed of the lower surface of the ball B is greater than the moving speed of the upper surface of the ball B, which is called "backspin". It is something.

Incidentally, although the behavior of the above-mentioned golf club head according to the present invention when hitting a ball has not been fully elucidated, it is presumed that the behavior shown in FIG. 8 occurs.

Figure 8 shows the behavior at the time of impact. When the ball B is hit with the face 2, the crown surface (shaded area) 5 curves upward, as shown by the two-dot broken line in Figure 8. and elastically deforms, and the face surface 2 rotates so as to be tilted rearward by an angle θ with its bottom point a as the rotation axis, returning to the original fixed loft angle θ. is added to and becomes larger (θ.10). Then, in accordance with the angle change of the face surface 2 at the time of hitting the ball, the ball B in contact with the face surface 2 receives a rotational force in a direction such that the ball B rolls downwardly of the face surface 2 due to a gear effect. This reduces the backspin of ball B.

[Embodiment] In this invention, the core of the head body 1 is filled with a filler 12 such as foamed synthetic resin, but a hollow structure may also be used.2 In addition, in molding such a head body 1, In addition to the above-mentioned stepwise injection molding method of raw material for FRP molding, there is also a resin injection method in which reinforcing fibers are selectively placed together with a core in a mold and then filled with matrix resin, or a crown of the head body is used. The main body of the head outer shell other than the face 5, the back surface 3, the sole surface 4, the toe side 6, the heel side 7 and the hosel portion 8, and the crown surface outer shell are separately molded. A possible method is to fit this crown surface outer shell part into the main body part of the head outer shell, or to use a hand lay-up method in which raw materials for FRP molding are manually stacked.

[Effects of the Invention] As is clear from the above description, the present invention has the crown surface of the head body mainly composed of a high-rigidity FRP outer shell structure formed of low-rigidity FRP. By making it rotate backwards, elastic energy can be stored in the crown area, and the loft angle of the face surface increases at the time of release, resulting in a larger initial launch angle and a gear effect that causes the ball to move backward. The amount of spin is reduced, the ball can achieve an ideal long trajectory with little soaring, and the flight distance of the ball can be significantly extended.

Furthermore, since the backspin of the ball is reduced by this, it is possible to provide a wood club head for golf that has excellent effects such as being able to obtain a large run after falling to the ground.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing one embodiment of a golf wood club head according to the present invention, FIG. 2 is a cross-sectional view taken along the line ■-■ in FIG. 1, and FIG. Figures 4 to 6 are explanatory diagrams showing the molding process of the wood club head, Figure 7 is an explanatory diagram comparing the trajectory of the ball when hit with a conventional ball, and Figure 8 is the same. FIG. 3 is an explanatory diagram showing the behavior of a club head when hitting a ball. 1...Head body, 2...Face surface, 3...Back surface, 4...
Sole surface, 5... Crown surface, 6... Toe side, 7... Heel side, 8... Hosel part, 11... High rigidity FRP, 13... Low rigidity FRP. 20/- 5th

Claims (1)

[Claims] (1) A golf club characterized in that at least the main parts of the face, back, and sole of the head body have an outer shell structure made of high-rigidity FRP, and the crown surface is formed of low-rigidity FRP. Wood club head.