Abstract: A golf ball 2 includes a core 4, a mid layer 6, and a cover 8. A difference DH in hardness between a surface and a central point of the core 4, a thickness Tm and a hardness Hm of the mid layer 6, a thickness Tc and a hardness Hc of the cover 8, and an amount of compressive deformation Sb of the golf ball 2 meet the following mathematical formulas (DH*Hm)/(Hc*Tc)>80 and ((Sb*Tc)/(Hc*Hm*Tm))*1000>0.75. A hardness Hc of the cover 8 is equal to or less than 40. A material of the cover 8 is a resin composition. The resin composition includes a polyurethane (A) and a polyrotaxane (B).

Abstract: A golf ball 2 includes a core 4, a mid layer 6, and a cover 8. A difference DH in hardness between a surface and a central point of the core 4, a thickness Tm and a hardness Hm of the mid layer 6, a thickness Tc and a hardness Hc of the cover 8, and an amount of compressive deformation Sb of the golf ball 2 meet the following mathematical formulas. (DH*Hm)/(Hc*c)>80 ((Sb*c)/(Hc*Hm*Tm))*1000>0.75 The golf ball 2 further includes a plurality of small dimples each having an area of less than 8.0 mm2 and a plurality of large dimples each having an area of equal to or greater than 8.0 mm2.

Abstract: An object of the present invention is to provide a golf ball showing an increased spin rate on approach shots under a wet condition while maintaining a spin rate on approach shots under a dry condition. The present invention provides a golf ball comprising a golf ball body and a paint film formed on a surface of the golf ball body, wherein the paint film has a multi-layered construction composed of two or more layers, and a difference (Min?Mout) between a 10% elastic modulus (Min) of an innermost layer of the paint film and a 10% elastic modulus (Mout) of an outermost layer of the paint film is 25 kgf/cm2 or more.

Abstract: An object of the present invention is to provide a golf ball traveling a great distance on driver shots. The present invention provides a golf ball comprising a spherical core including an inner layer and an outer layer, wherein a difference (HX+1?HX?1) between a hardness (HX+1) at a point outwardly away in a radial direction from a boundary between the inner layer and the outer layer of the spherical core by 1 mm and a hardness (HX?1) at a point inwardly away in the radial direction from the boundary between the inner layer and the outer layer of the spherical core by 1 mm is 0 or more in Shore C hardness, a surface hardness (HX+Y) of the spherical core is more than 70 in Shore C hardness, an angle ? of a hardness gradient of the inner layer is 0° or more, a difference (???) between the angle ? and an angle ? of a hardness gradient of the outer layer is 0° or more, and the intermediate layer has a highest hardness among the constituent members of the golf ball.

Abstract: An object of the present invention is to provide a golf ball traveling a great distance on driver shots.

Abstract: A golf ball 2 includes a core 4, a mid layer 6, a cover 8 and a paint layer 10. The core 4 includes a center 12 and an envelope layer 14. The golf ball 2 satisfies the following mathematical formulas. In the mathematical formulas, Hm represents a Shore D hardness of the mid layer, Hc represents a Shore D hardness of the cover, and Hb represents a Shore D hardness of the surface of the golf ball. The golf ball 2 has a large number of dimples 16 on a surface thereof. The number of planes that can divide a pattern of the dimples so that divided patterns are mirror symmetry to each other is one.

Abstract: A device is provided with an obtaining unit, a specifying unit, and a determination unit. The obtaining unit obtains measurement data in which the golfer has performed a test-hit of at least one number of a golf club for each type of golf club from among the multiple types of golf clubs. The specifying unit specifies a relationship of correspondence between a loft angle and a flight-distance for each type of golf club based on the measurement data. The determination unit determines, based on the relationship of correspondence, a type of golf club having a large flight-distance with respect to a loft angle as a best-match type, which is a type of golf club best matched to the golfer.

Abstract: This method simulates a run which is a distance between a landing point and a final arriving point using an initial condition of a hit ball and an actually measured falling condition. Preferably, the initial condition includes initial side spin. Preferably, the falling condition is a falling velocity. Preferably, a calculation formula of the run is a quadratic function having the initial condition and the falling condition as variables. Preferably, when the run is defined as Dr (yard); a target direction component of the falling velocity is defined as Vx (m/s); a vertical direction component of the falling velocity is defined as Vy (m/s); and the initial side spin is defined as S (rpm), the run is calculated according to the following formula: Dr=Ci×Vx2?C2×Vx+C3×Vy2+C4×Vy?Cs×S+C6.

Abstract: An object of the present invention is to provide a golf ball traveling a great distance on driver shots. The present invention provides a golf ball comprising a spherical core including an inner layer and an outer layer, wherein a difference (HX+1?HX?1) between a hardness (HX+1) at a point outwardly away in a radial direction from a boundary between the inner layer and the outer layer of the spherical core by 1 mm and a hardness (HX?1) at a point inwardly away in the radial direction from the boundary between the inner layer and the outer layer of the spherical core by 1 mm is 0 or more in Shore C hardness, a surface hardness (HX+Y) of the spherical core is more than 70 in Shore C hardness, an angle ? of a hardness gradient of the inner layer is 0° or more, and a difference (???) between the angle ? and an angle ? of a hardness gradient of the outer layer is 0° or more.

Abstract: An object of the present invention is to provide a golf ball traveling a great flight distance on driver shots and an excellent shot feeling. The present invention provides a golf ball comprising a spherical core, an intermediate layer covering the spherical core, and a cover covering the intermediate layer, wherein a material hardness (Hm) of a resin composition constituting the intermediate layer ranges from 65 to 80 in Shore D hardness, a material hardness (Hc) of a resin composition constituting the cover ranges from 57 to 72 in Shore D hardness, a hardness difference (Hm?Hc) between the material hardness (Hm) and the material hardness (Hc) is more than 0, and the intermediate layer has a surface hardness satisfying a hardness difference (HmsC?HmsD) between a hardness thereof shown in Shore C hardness (HmsC) and a hardness thereof shown in Shore D hardness (HmsD) of 27 or less.

Abstract: A measuring apparatus 10 for a golf club 34 includes: a club camera 20 capable of photographing the golf club; a control part 30 capable of controlling a timing at which the golf club is photographed; and three sensors capable of detecting passage of the golf club 34. The three sensors are defined as a first sensor S1, a second sensor S2, and a third sensor S3 in this order from a point close to a position of a golf ball. When a club speed calculated based on the passage of the golf club detected by the second sensor S2 and the third sensor S3 is equal to or greater than a predetermined threshold value, the control part generates a trigger signal for starting to photograph the golf club. The measuring apparatus 10 can effectively suppress erroneous generation of the trigger signal.

Abstract: A golf ball 2 includes a core 4, a mid layer 6, a cover 8 and a paint layer 10. The core 4 includes a center 12 and an envelope layer 14. The golf ball 2 satisfies the following mathematical formulas. In the mathematical formulas, Tm represents a thickness of the mid layer, Tcmin represents a minimum thickness of the cover, Tcmax represents a maximum thickness of the cover, and Tp represents a thickness of the paint layer. The golf ball 2 has a large number of dimples 16 on a surface thereof. The number of planes that can divide a pattern of the dimples so that divided patterns are mirror symmetry to each other is one. Tm>Tcmax?Tcmin>Tp (Tcmas?Tcmin)?0.15 mm 0.15?(Tp/Tcmin)?0.

Abstract: A golf ball 2 includes a core 4, a mid layer 6, a cover 8 and a paint layer 10. The core 4 includes a center 12 and an envelope layer 14. The golf ball 2 satisfies the following mathematical formulas. In the mathematical formulas, Hm represents a Shore D hardness of the mid layer, Hc represents a Shore D hardness of the cover, and Hb represents a Shore D hardness of the surface of the golf ball. The golf ball 2 has a large number of dimples 16 on a surface thereof. The number of planes that can divide a pattern of the dimples so that divided patterns are mirror symmetry to each other is one.

Abstract: A golf ball 2 includes a core 4, an envelope layer 6 positioned outside the core 4, a mid layer 8 positioned outside the envelope layer 6, and a cover 10 positioned outside the mid layer 8. The core 4 includes a spherical center 12 and a core outer layer 14 positioned outside the center 12. The center 12 has a diameter of 1 mm or greater and 15 mm or less. The difference (H4?H3) between the JIS-C hardness H4 of the core 4 at its surface and the JIS-C hardness H3 of the core outer layer 14 at its innermost portion is equal to or greater than 10. The cover 10 has a Shore D hardness H7 less than 40. The Shore D hardnesses H5, H6 and H7 of the envelope layer 6, the mid layer 8, and the cover 10 satisfy that H5>H6?H7.

Abstract: A device is provided with an obtaining unit, a specifying unit, and a determination unit. The obtaining unit obtains measurement data in which the golfer has performed a test-hit of at least one number of a golf club for each type of golf club from among the multiple types of golf clubs. The specifying unit specifies a relationship of correspondence between a loft angle and a flight-distance for each type of golf club based on the measurement data. The determination unit determines, based on the relationship of correspondence, a type of golf club having a large flight-distance with respect to a loft angle as a best-match type, which is a type of golf club best matched to the golfer.

Abstract: The object of the present invention is to provide a golf ball that satisfies both of the flight distance at the shot with a driver, a long iron, and a middle iron and the controllability at the approach shot with a short iron and is also excellent in the abrasion resistance of the cover.

Abstract: A swing analysis apparatus 10 for a golf club includes a club camera 20 continuously photographing a behavior of a golf club 34, a ball camera 22 continuously photographing a behavior of a golf ball 36, and an information processor 32. The club camera 20 is positioned in front of a golf player. A straight line C passes through a center of a lens of the club camera 22 and a center of the golf ball 36. An angle ?c between the straight line C and a vertical line Z is 10 degrees or greater and 20 degrees or less. The information processor 32 measures a synchronized club behavior value from synchronized club image data. The information processor 32 measures a synchronized ball behavior value from synchronized ball image data. The information processor 32 stores the synchronized club behavior value and the synchronized ball behavior value.

Abstract: A plurality of golf clubs having mutually different flex point rates of a shaft is prepared. A subject hits a golf ball with one reference club included in the golf clubs. A face angle of the golf club immediately before hitting is measured by an apparatus 10. A recommended flex point rate P is calculated by substituting, into the following mathematical expression, the face angle Q and the flex point rate R of the reference club: P=0.8648·Q+R?5.033 A golf club having a shaft whose difference between the flex point rate and the recommended flex point rate P is within a predetermined range is selected as a recommended club. The subject hits a golf ball with the recommended club. The apparatus 10 measures a speed, a launch angle, a backspin speed, a sidespin speed, and a deflection angle of the golf ball.

Abstract: The present invention is directed to a golf ball having a center, an envelope layer, an intermediate layer and a cover, wherein the intermediate layer has a thickness less than 1.2 mm, the envelope layer has a hardness Hs of 60 or more, the intermediate layer has a hardness Hm from 40 to 60, and the cover has a hardness Hc less than 40 in Shore D hardness, and the hardness Hs, Hm and Hc satisfy a following mathematical expression: Hs>Hm>Hc, and the intermediate layer composition has a flexural modulus from 150 MPa to 450 MPa, a maximum loss factor (tan ?) between ?20° C. and 0° C. of 0.08 or less, a rebound resilience of 55% or more.

Abstract: A golf ball 2 includes a spherical core 4, an envelope layer 6 positioned outside the core 4, a mid layer 8 positioned outside the envelope layer 6, a reinforcing layer 10 positioned outside the mid layer 8, and a cover 12 positioned outside the reinforcing layer 10. The mid layer 8 has a thickness Tm less than 1.0 mm. The envelope layer 6 has a Shore D hardness Hs of 60 or greater. The mid layer 8 has a Shore D hardness Hm of 50 or greater and 65 or less. The cover 12 has a Shore D hardness Hc less than 40. The golf ball 2 satisfies that Hs>Hm>Hc. The principal components of the base materials of the envelope layer 6, the mid layer 8 and the cover 12 are an ionomer resin, an ionomer resin and a thermoplastic polyurethane elastomer, respectively.