MULTI-PIECE GOLF BALL

摘要

An object of the present invention is to provide a golf ball showing a small ratio of a spin rate on driver shots to a spin rate on approach shots. The present invention provides a multi-piece golf ball comprising a spherical center, three or more envelope layers covering the spherical center, and a cover covering the envelope layers, wherein adjacent two envelope layers are formed so as to include a region composed of elements having a hitting deformation ratio of 30% or more, the hitting deformation ratio being obtained by analyzing a specified golf ball model by a finite element method; and the envelope layer which is radially outwardly positioned of the adjacent two envelope layers has a lowest hardness among all the envelope layers.

主权项

1. A multi-piece golf ball comprising a spherical center, three or more envelope layers covering the spherical center, and a cover covering the envelope layers, wherein
adjacent two envelope layers are formed so as to include a region composed of elements having a hitting deformation ratio of 30% or more, the hitting deformation ratio being obtained by analyzing a golf ball model described in Table 1 shown below by a finite element method; and the envelope layer which is radially outwardly positioned of the adjacent two envelope layers has a lowest hardness (Hs) among all the envelope layers.TABLE 1Distance (mm)Distance (%)Tensilefrom central pointfrom central pointHardnessmodulusPoisson'sDensityof golf ballof golf ball(Shore C)(MPa)ratio(g/cm3)Core 10-2.00mm 0%-9.4%70530.491.118Core 22.00-4.00mm 9.4%-18.7%72570.491.118Core 34.00-6.00mm18.7%-28.1%73640.491.118Core 46.00-8.00mm28.1%-37.5%74650.491.118Core 58.00-10.00mm37.5%-46.8%74650.491.118Core 610.00-12.00mm46.8%-56.2%74650.491.118Core 712.00-14.00mm56.2%-65.6%74650.491.118Core 814.00-16.00mm65.6%-74.9%77770.491.118Core 916.00-18.00mm74.9%-84.3%77770.491.118Core 1018.00-18.85mm84.3%-88.3%79880.491.118Core 1118.85-19.35mm88.3%-90.6%81970.491.118Core 1219.35-19.85mm90.6%-93.0%831080.491.118Intermediate19.85-20.85mm93.0%-97.7%942900.490.989layerCover20.85-21.35mm97.7%-100% 46160.491.101