Golf club head

Abstract

A golf club having an increased moment of inertia and improved ball-hitting directionality is provided. A metal hollow golf club head comprises: a face portion; a crown portion; and a sole portion, and when the golf club has a lie angle of 60° with its club head volume being within 470 cm³, a moment of inertia about the axial line centered on the plumb line passing through the golf club head center of gravity is 5000 to 6000 g-cm². In order to increase the moment of inertia, the thickness of the center portion of the crown portion is reduced by chemical etching, and a mass, including the portion of mass reduction, is positioned in the sole portion on the side of the toe portion; moreover, the separation distance from the center of gravity to the mass is increased.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to a golf club head with improved ball-hitting directionality, and more specifically, relates to a golf club head having a large moment of inertia and improved stability of direction of a hit ball.[0003]2. Description of the Related Art[0004]Various improvements have been made to golf clubs, to extend flight distances, and to enable stable hitting of the ball. Flight distances directly affect scores, and so through improvements so as to broaden the effective range (“sweet” area) of the striking point on a golf club head (hereafter also simply called a “head”), improvements in the position of the effective area, improvements in the material of the face surface, and similar, the probabilistic ball flight distance has been extended; consequently scores have improved, and players using such heads have found them beneficial. Moreover, in order to improve scores, golf clubs have been sought for w...

AI Technical Summary

Benefits of technology

[0034]As explained in detail above, a golf club of this invention employs a hollow golf club head, the materials comprised by which are in essence all metals; under the constraints that the head volume be 470 cm3 or less (including a tolerance of 10 cm3), that the head mass be 210 g or less, and that the head characteristic time (CT value) related to the restitution characteristic be 257 μs or less (including a tolerance of 18 μs), a method and conditions were discovered for obtaining a golf club head for which the moment of inertia about the axial line centered on the plu

Problems solved by technology

There is a trend toward larger heads, but the masses of the constituent parts of a head adds up, and the swing balance, which is a criterion for ease of swinging of a club, becomes heavy.

As a result, head masses have in the prior art been no greater than approximately 210 g. That is, given the configuration of the prior art, although heads have tended to increase in size the total mass has been limited, and so excess mass to control the position of the center of gravity, or in other words, excess mass to increase the moment of inertia has in the prior art been limited to approximately 10 g, due to the constraint that the total mass should not be increased.

Further, the hosel portion connected to the shaft is positioned on one end of the face portion, and the weight of this portion is also relatively great.

Due to such constraints, it is extremely difficult to increase

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