Golf ball

Abstract

The present invention provides a golf ball that achieves a satisfactorily long carry distance when hit with a driver and that accurately generates a desirable amount of backspin in an approach shot. The golf ball of the present invention has a spherical main part, a plurality of ribs formed on the surface of the main part, an interlayer that is placed in depressions surrounded by the ribs and has a hardness greater than that of the ribs, an inner cover that covers the interlayer, and an outer cover that covers the inner cover and has a hardness lower than the inner cover.

Description

BACKGROUND OF THE INVENTION[0001](1) Field of the Invention[0002]The present invention relates to a multi-layered golf ball.[0003](2) Description of the Related Art[0004]Recently, several kinds of golf balls exhibiting both high rebound resilience and a soft feel when hit have been proposed. One example of such a golf ball is a multi-layered golf ball in which the ball is composed of a plurality of layers. For example, WO2005 / 089883 (Patent Document 1: Domestic re-publication of PCT international application) discloses a golf ball having ribs provided on the surface of a spherical main part, and an interlayer formed in the depressions surrounded by the ribs. By setting the hardness of the interlayer higher than that of the ribs, the golf ball described above achieves the following effects. When a golf club comes into contact with a golf ball, usually the ball is deformed in the circumferential direction due to friction generated between the ball and the clubface. When the deformed b...

AI Technical Summary

Benefits of technology

[0009]In this structure, because the hardness of the ribs is lower than that of the interlayer, the ribs deform to a greater degree than the interlayer when hit. The ribs are not mere protrusions but are structured so as to form walls surrounding the interlayer, and therefore when the ribs are returning to their original condition, the force of the entire wall strongly acts on the interlayer from the perimeter of the interlayer, and this increases the force opposing the backspin. As a result, a significantly longer carry distance can be achieved. This effect is particularly remarkable when the ball is hit by a driver, etc., which is designed to attain a long carry distance.

[0010]Because the inner cover is provided between the interlayer and the outer cover, direct transmission of the striking force to the interlayer and the ribs can be prevented in an approach shot, such as one performed using an iron, in which the deformation of the ball is small. As a result, the increase of the force opposing the backspin can be prevented. Therefore, the golf ball of the present invention achieves a long carry distance by reducing the amount of backspin when hit by a driver. Furthermore, the golf ball of the present invention can be accurately stopped by the application of backspin when it is hit by an iron.

[0011]Because the hardness of the outer cover is lower than that of the inner cover, a soft feeling can be obtained when hit. Furthermore, because this structure can increase the deformation of the outer cover, the backspin effect can be increased when hit by an iron. Because the hardness of the inner cover is greater than that of the outer cover in this embodiment, even though the outer cover has a soft feeling when hit, a high rebound resilience can be attained by the inner cover. This achieves a longer carry distance. The rebound resilience can be increased by setting the Shore D hardness of the inner cover, for example, to 55 to 70. A soft feeling when hit can be obtained by setting the Shore D hardness of the outer cover to 54 to 60.

[0012]In the golf ball described above, the inner cover can be made harder than the interlayer. This makes the hardness of the inner portion in the radical direction lower than that of the inner cover, reducing the hitting hardness attributable to the inner cover.

[0013]In the golf ball described above, the total thickness of the inner cover and the outer cover can be 1.9 mm or more. The deformation of the ball in an approach shot using a wedge may sometimes reach about 2.0 mm. Having the total thickness of the inner cover and the outer cover 1.9 mm or more makes it difficult for the hitting impact to be transmitted to the interlayer and ribs when making an approach shot using a wedge. This makes it possible to effectively reduce the backspin-canceling effect of the ribs. Therefore, the ball can be accurately stopped in an approach shot using a wedge. Furthermore, having such a total thickness can also improve the durability of the ball.

[0014]In the golf ball described above, the hardness of the main part can be made the same as that of the ribs by forming the main part and the ribs as a unit. In this structure, the hardness of the interlayer is not only greater than that of the ribs but is also greater than that of the main part, so the amount of spin can be reduced to obtain a longer carry distance.

Problems solved by technology

However, it has a drawback when it is hit with an iron in an approach shot.

In an approach shot, it is important to stop the ball by using backspin; however, the ball cannot be accurately stopped when the force opposing the backspin is increased as described above.

Images