US20180169480A1 - Golf ball - Google Patents

Golf ball Download PDF

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Publication number
US20180169480A1
US20180169480A1 US15/786,129 US201715786129A US2018169480A1 US 20180169480 A1 US20180169480 A1 US 20180169480A1 US 201715786129 A US201715786129 A US 201715786129A US 2018169480 A1 US2018169480 A1 US 2018169480A1
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Prior art keywords
point
axis
coordinates
golf ball
hardness
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Abandoned
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US15/786,129
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English (en)
Inventor
Hidetaka INOUE
Kazuya Kamino
Takahiro Sajima
Kohei Mimura
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Sumitomo Rubber Industries Ltd
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Dunlop Sports Co Ltd
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Assigned to DUNLOP SPORTS CO. LTD. reassignment DUNLOP SPORTS CO. LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: INOUE, HIDETAKA, KAMINO, KAZUYA, MIMURA, KOHEI, SAJIMA, TAKAHIRO
Assigned to SUMITOMO RUBBER INDUSTRIES, LTD. reassignment SUMITOMO RUBBER INDUSTRIES, LTD. MERGER (SEE DOCUMENT FOR DETAILS). Assignors: DUNLOP SPORTS CO. LTD.
Publication of US20180169480A1 publication Critical patent/US20180169480A1/en
Abandoned legal-status Critical Current

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    • A—HUMAN NECESSITIES
    • A63—SPORTS; GAMES; AMUSEMENTS
    • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
    • A63B37/00—Solid balls; Rigid hollow balls; Marbles
    • A63B37/0003—Golf balls
    • A63B37/007—Characteristics of the ball as a whole
    • A63B37/0072—Characteristics of the ball as a whole with a specified number of layers
    • A63B37/0075—Three piece balls, i.e. cover, intermediate layer and core
    • A—HUMAN NECESSITIES
    • A63—SPORTS; GAMES; AMUSEMENTS
    • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
    • A63B37/00—Solid balls; Rigid hollow balls; Marbles
    • A63B37/0003—Golf balls
    • A63B37/0004—Surface depressions or protrusions
    • A63B37/0006—Arrangement or layout of dimples
    • A—HUMAN NECESSITIES
    • A63—SPORTS; GAMES; AMUSEMENTS
    • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
    • A63B37/00—Solid balls; Rigid hollow balls; Marbles
    • A63B37/0003—Golf balls
    • A63B37/0004—Surface depressions or protrusions
    • A63B37/0007—Non-circular dimples
    • A—HUMAN NECESSITIES
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    • A63B37/00—Solid balls; Rigid hollow balls; Marbles
    • A63B37/0003—Golf balls
    • A63B37/0004—Surface depressions or protrusions
    • A63B37/0012—Dimple profile, i.e. cross-sectional view
    • A—HUMAN NECESSITIES
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    • A—HUMAN NECESSITIES
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    • A—HUMAN NECESSITIES
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    • A63B37/00221—Coatings, e.g. paint films; Markings characterised by the material
    • A—HUMAN NECESSITIES
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    • A—HUMAN NECESSITIES
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    • A—HUMAN NECESSITIES
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    • A63B37/0063—Hardness gradient
    • A—HUMAN NECESSITIES
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    • A—HUMAN NECESSITIES
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    • A—HUMAN NECESSITIES
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    • A63B37/00—Solid balls; Rigid hollow balls; Marbles
    • A63B37/0003—Golf balls
    • A63B37/007—Characteristics of the ball as a whole
    • A63B37/0072—Characteristics of the ball as a whole with a specified number of layers
    • A63B37/0076—Multi-piece balls, i.e. having two or more intermediate layers
    • A—HUMAN NECESSITIES
    • A63—SPORTS; GAMES; AMUSEMENTS
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    • A—HUMAN NECESSITIES
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    • A—HUMAN NECESSITIES
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    • A63B37/00922—Hardness distribution amongst different ball layers whereby hardness of the cover is lower than hardness of the intermediate layers
    • A—HUMAN NECESSITIES
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    • A63B37/0096—Spin rate
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    • A63B45/00—Apparatus or methods for manufacturing balls

Definitions

  • the present invention relates to golf balls. Specifically, the present invention relates to golf balls including a core, a mid layer, a cover, and dimples.
  • the face of a golf club has a loft angle.
  • backspin due to the loft angle occurs in the golf ball.
  • the golf ball flies with the backspin.
  • a backspin rate When a backspin rate is high, the run of the golf ball after landing is short. By using a golf ball having a high backspin rate, a golf player can cause the golf ball to stop at a target point. When a sidespin rate is high, the golf ball tends to curve. By using a golf ball having a high sidespin rate, a golf player can intentionally cause the golf ball to curve.
  • a golf ball to which backspin is easily provided has excellent controllability. Golf players particularly place importance on controllability upon approach shots.
  • the dimples disturb the air flow around the golf ball during flight to cause turbulent flow separation. This phenomenon is referred to as “turbulization”. Due to the turbulization, separation points of the air from the golf ball shift backwards leading to a reduction of drag. The turbulization promotes the displacement between the separation point on the upper side and the separation point on the lower side of the golf ball, which results from the backspin, thereby enhancing the lift force that acts upon the golf ball. The reduction of drag and the enhancement of lift force are referred to as a “dimple effect”. Excellent dimples efficiently disturb the air flow. The excellent dimples produce a long flight distance.
  • JPH4-109968 discloses a golf ball in which the dimple pattern of each hemisphere can be divided into six units.
  • JP2004-243124 discloses a golf ball in which the dimple pattern near each pole can be divided into four units and the dimple pattern near the equator can be divided into five units.
  • JP2011-10667 discloses a golf ball in which a parameter dependent on the shapes of dimples falls within a predetermined range.
  • An object of the present invention is to provide a golf ball having excellent flight performance and excellent controllability upon an approach shot.
  • a golf ball according to the present invention includes a core, a mid layer positioned outside the core, and a cover positioned outside the mid layer.
  • a Shore C hardness Hmc of the mid layer is greater than a Shore C hardness Hs at a surface of the core.
  • a Shore D hardness He of the cover is less than a Shore D hardness Hm of the mid layer.
  • the golf ball further includes a plurality of dimples on a surface thereof.
  • a minimum value of 15 peak values obtained by executing steps (a) to (h) for each of 15 axes Ax is not less than 95 mm, when spherical polar coordinates of a point that is located on a surface of a phantom sphere of the golf ball and has a latitude of ⁇ (degrees) and a longitude of ⁇ (degrees) are represented by ( ⁇ , ⁇ ), the 15 axes Ax being
  • a minimum value of 15 orders obtained by executing the steps (a) to (h) is not less than 27.
  • a maximum value of the 15 orders obtained by executing the steps (a) to (h) is not greater than 37.
  • An average of the 15 orders obtained by executing the steps (a) to (h) is not less than 30 and not greater than 34.
  • the dimple pattern of the golf ball according to the present invention has an excellent aerodynamic characteristic.
  • the golf ball has excellent flight performance. When the golf ball is hit with a short iron, the spin rate is high.
  • the golf ball has excellent controllability upon an approach shot. The golf ball achieves both desired flight performance and desired controllability.
  • an average of the 15 peak values obtained by executing the steps (a) to (h) is not less than 200 mm.
  • a total volume of the dimples is not less than 450 mm 3 and not greater than 750 mm 3 .
  • a difference DH in Shore C hardness between the surface and a central point of the core, a thickness Tm (mm) and the Shore D hardness Hm of the mid layer, a thickness Tc (mm) and the Shore D hardness He of the cover, and an amount of compressive deformation Sb (mm) of the golf ball satisfy the following mathematical formulas (i) and (ii).
  • a difference (Hmc ⁇ Hs) between the Shore C hardness Hmc of the mid layer and the Shore C hardness Hs at the surface of the core is not less than 5.
  • a difference (Hm ⁇ Hc) between the Shore D hardness Hm of the mid layer and the Shore D hardness He of the cover is not less than 20.
  • FIG. 1 is a schematic cross-sectional view of a golf ball according to an embodiment of the present invention
  • FIG. 2 is an enlarged front view of the golf ball in FIG. 1 ;
  • FIG. 3 is a plan view of the golf ball in FIG. 2 ;
  • FIG. 4 is a partially enlarged cross-sectional view of the golf ball in FIG. 1 ;
  • FIG. 5 is a schematic diagram for explaining an evaluation method for the golf ball in FIG. 2 ;
  • FIG. 6 is a schematic diagram for explaining the evaluation method for the golf ball in FIG. 2 ;
  • FIG. 7 is a schematic cross-sectional view for explaining the evaluation method for the golf ball in FIG. 2 ;
  • FIG. 8 is a schematic cross-sectional view for explaining the evaluation method for the golf ball in FIG. 2 ;
  • FIG. 9 is a graph showing an evaluation result of the golf ball in FIG. 2 ;
  • FIG. 10 is a graph showing another evaluation result of the golf ball in FIG. 2 ;
  • FIG. 11 is a schematic diagram for explaining the evaluation method for the golf ball in FIG. 2 ;
  • FIG. 12 is a schematic diagram for explaining the evaluation method for the golf ball in FIG. 2 ;
  • FIG. 13 is a schematic diagram for explaining the evaluation method for the golf ball in FIG. 2 ;
  • FIG. 14 is a schematic diagram for explaining the evaluation method for the golf ball in FIG. 2 ;
  • FIG. 15 is a schematic diagram for explaining the evaluation method for the golf ball in FIG. 2 ;
  • FIG. 16 is a schematic diagram for explaining the evaluation method for the golf ball in FIG. 2 ;
  • FIG. 17 is a schematic diagram for explaining the evaluation method for the golf ball in FIG. 2 ;
  • FIG. 18 is a schematic diagram for explaining the evaluation method for the golf ball in FIG. 2 ;
  • FIG. 19 is a schematic diagram for explaining the evaluation method for the golf ball in FIG. 2 ;
  • FIG. 20 is a schematic diagram for explaining the evaluation method for the golf ball in FIG. 2 ;
  • FIG. 21 is a schematic diagram for explaining the evaluation method for the golf ball in FIG. 2 ;
  • FIG. 22 is a schematic diagram for explaining the evaluation method for the golf ball in FIG. 2 ;
  • FIG. 23 is a schematic diagram for explaining the evaluation method for the golf ball in FIG. 2 ;
  • FIG. 24 is a schematic diagram for explaining the evaluation method for the golf ball in FIG. 2 ;
  • FIG. 25 is a front view of a golf ball according to Example 2 of the present invention.
  • FIG. 26 is a plan view of the golf ball in FIG. 25 ;
  • FIG. 27 is a front view of a golf ball according to Example 3 of the present invention.
  • FIG. 28 is a plan view of the golf ball in FIG. 27 ;
  • FIG. 29 is a front view of a golf ball according to Comparative Example 1;
  • FIG. 30 is a plan view of the golf ball in FIG. 29 ;
  • FIG. 31 is a front view of a golf ball according to Comparative Example 2.
  • FIG. 32 is a plan view of the golf ball in FIG. 31 ;
  • FIG. 33 is a front view of a golf ball according to Comparative Example 3.
  • FIG. 34 is a plan view of the golf ball in FIG. 33 ;
  • FIG. 35 is a front view of a golf ball according to Comparative Example 4.
  • FIG. 36 is a plan view of the golf ball in FIG. 35 .
  • a golf ball 2 shown in FIG. 1 includes a spherical core 4 , a mid layer 6 positioned outside the core 4 , and a cover 8 positioned outside the mid layer 6 .
  • the golf ball 2 has a plurality of dimples 10 on the surface thereof. Of the surface of the golf ball 2 , a part other than the dimples 10 is a land 12 .
  • the golf ball 2 includes a paint layer and a mark layer on the external side of the cover 8 although these layers are not shown in the drawing.
  • the golf ball 2 may include another layer between the core 4 and the mid layer 6 .
  • the golf ball 2 may include another layer between the mid layer 6 and the cover 8 .
  • the golf ball 2 preferably has a diameter of not less than 40 mm and not greater than 45 mm. From the viewpoint of conformity to the rules established by the United States Golf Association (USGA), the diameter is particularly preferably not less than 42.67 mm. In light of suppression of air resistance, the diameter is more preferably not greater than 44 mm and particularly preferably not greater than 42.80 mm.
  • the golf ball 2 preferably has a weight of not less than 40 g and not greater than 50 g. In light of attainment of great inertia, the weight is more preferably not less than 44 g and particularly preferably not less than 45.00 g. From the viewpoint of conformity to the rules established by the USGA, the weight is particularly preferably not greater than 45.93 g.
  • the core 4 is formed by crosslinking a rubber composition.
  • base rubbers for use in the rubber composition include polybutadienes, polyisoprenes, styrene-butadiene copolymers, ethylene-propylene-diene copolymers, and natural rubbers. In light of resilience performance, polybutadienes are preferable.
  • polybutadiene and another rubber are used in combination, it is preferred if the polybutadiene is a principal component.
  • the proportion of the polybutadiene to the entire base rubber is preferably not less than 50% by weight and particularly preferably not less than 80% by weight.
  • a polybutadiene in which the proportion of cis-1,4 bonds is not less than 80% is particularly preferable.
  • the rubber composition of the core 4 preferably includes a co-crosslinking agent.
  • co-crosslinking agents in light of resilience performance are monovalent or bivalent metal salts of an ⁇ , ⁇ -unsaturated carboxylic acid having 2 to 8 carbon atoms.
  • preferable co-crosslinking agents include zinc acrylate, magnesium acrylate, zinc methacrylate, and magnesium methacrylate. In light of resilience performance, zinc acrylate and zinc methacrylate are particularly preferable.
  • the rubber composition may include a metal oxide and an ⁇ , ⁇ -unsaturated carboxylic acid having 2 to 8 carbon atoms. They both react with each other in the rubber composition to obtain a salt.
  • the salt serves as a co-crosslinking agent.
  • preferable ⁇ , ⁇ -unsaturated carboxylic acids include acrylic acid and methacrylic acid.
  • preferable metal oxides include zinc oxide and magnesium oxide.
  • the amount of the co-crosslinking agent per 100 parts by weight of the base rubber is preferably not less than 10 parts by weight and particularly preferably not less than 15 parts by weight. In light of soft feel at impact, the amount is preferably not greater than 50 parts by weight and particularly preferably not greater than 45 parts by weight.
  • the rubber composition of the core 4 includes an organic peroxide.
  • the organic peroxide serves as a crosslinking initiator.
  • the organic peroxide contributes to the resilience performance of the golf ball 2 .
  • suitable organic peroxides include dicumyl peroxide, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, and di-t-butyl peroxide.
  • An organic peroxide with particularly high versatility is dicumyl peroxide.
  • the amount of the organic peroxide per 100 parts by weight of the base rubber is preferably not less than 0.1 parts by weight, more preferably not less than 0.3 parts by weight, and particularly preferably not less than 0.5 parts by weight. In light of soft feel at impact, the amount is preferably not greater than 3.0 parts by weight, more preferably not greater than 2.8 parts by weight, and particularly preferably not greater than 2.5 parts by weight.
  • the rubber composition of the core 4 includes an organic sulfur compound.
  • Organic sulfur compounds include naphthalenethiol compounds, benzenethiol compounds, and disulfide compounds.
  • naphthalenethiol compounds include 1-naphthalenethiol, 2-naphthalenethiol, 4-chloro-1-naphthalenethiol, 4-bromo-1-naphthalenethiol, 1-chloro-2-naphthalenethiol, l-bromo-2-naphthalenethiol, l-fluoro-2-naphthalenethiol, l-cyano-2-naphthalenethiol, and 1-acetyl-2-naphthalenethiol.
  • benzenethiol compounds include benzenethiol, 4-chlorobenzenethiol, 3-chlorobenzenethiol, 4-bromobenzenethiol, 3-bromobenzenethiol, 4-fluorobenzenethiol, 4-iodobenzenethiol, 2,5-dichlorobenzenethiol, 3,5-dichlorobenzenethiol, 2,6-dichlorobenzenethiol, 2,5-dibromobenzenethiol, 3,5-dibromobenzenethiol, 2-chloro-5-bromobenzenethiol, 2,4,6-trichlorobenzenethiol, 2,3,4,5,6-pentachlorobenzenethiol, 2,3,4,5,6-pentafluorobenzenethiol, 4-cyanobenzenethiol, 2-cyanobenzenethiol, 4-nitrobenzenethiol, and 2-
  • disulfide compounds include diphenyl disulfide, bis(4-chlorophenyl)disulfide, bis(3-chlorophenyl)disulfide, bis(4-bromophenyl)disulfide, bis(3-bromophenyl)disulfide, bis(4-fluorophenyl)disulfide, bis(4-iodophenyl)disulfide, bis(4-cyanophenyl)disulfide, bis(2,5-dichlorophenyl)disulfide, bis(3,5-dichlorophenyl)disulfide, bis(2,6-dichlorophenyl)disulfide, bis(2,5-dibromophenyl)disulfide, bis(3,5-dibromophenyl)disulfide, bis(2-chloro-5-bromophenyl)disulfide, bis(
  • the amount of the organic sulfur compound per 100 parts by weight of the base rubber is preferably not less than 0.1 parts by weight and particularly preferably not less than 0.2 parts by weight. In light of soft feel at impact, the amount is preferably not greater than 1.5 parts by weight, more preferably not greater than 1.0 parts by weight, and particularly preferably not greater than 0.8 parts by weight.
  • Two or more organic sulfur compounds may be used in combination. A naphthalenethiol compound and a disulfide compound are preferably used in combination.
  • the rubber composition of the core 4 includes a carboxylic acid or a carboxylate.
  • the core 4 including a carboxylic acid or a carboxylate has a low hardness around the central point thereof.
  • the core 4 has an outer-hard/inner-soft structure.
  • the spin rate is low.
  • the golf ball 2 having a low spin rate a large flight distance is obtained.
  • preferable carboxylic acids include benzoic acid.
  • preferable carboxylates include zinc octoate and zinc stearate.
  • the rubber composition particularly preferably includes benzoic acid.
  • the total amount of the carboxylic acid and the carboxylate per 100 parts by weight of the base rubber is preferably not less than 1 parts by weight and not greater than 20 parts by weight.
  • the rubber composition of the core 4 may include a filler for the purpose of specific gravity adjustment and the like.
  • suitable fillers include zinc oxide, barium sulfate, calcium carbonate, and magnesium carbonate.
  • the amount of the filler is determined as appropriate so that the intended specific gravity of the core 4 is accomplished.
  • the rubber composition may include various additives, such as sulfur, an anti-aging agent, a coloring agent, a plasticizer, a dispersant, and the like, in an adequate amount.
  • the rubber composition may include crosslinked rubber powder or synthetic resin powder.
  • the core 4 preferably has a diameter of not less than 38.0 mm.
  • the golf ball 2 including the core 4 having a diameter of not less than 38.0 mm has excellent resilience performance.
  • the diameter is more preferably not less than 38.5 mm and particularly preferably not less than 39.5 mm.
  • the diameter is preferably not greater than 41.0 mm and particularly preferably not greater than 40.5 mm.
  • the core 4 has a weight of preferably not less than 10 g and not greater than 40 g.
  • the temperature for crosslinking the core 4 is not lower than 140° C. and not higher than 180° C.
  • the time period for crosslinking the core 4 is not shorter than 10 minutes and not longer than 60 minutes.
  • the core 4 may include a center and an envelope layer.
  • the core 4 may have three or more layers.
  • the core 4 may have a rib on the surface thereof.
  • the core 4 may be hollow.
  • the difference DH between a hardness Hs at the surface of the core 4 and a hardness Ho at the central point of the core 4 is preferably not less than 15.
  • the core 4 in which the difference DH is not less than 15 has a so-called outer-hard/inner-soft structure.
  • an appropriate trajectory height and appropriate flight duration are required.
  • the run after landing is short.
  • the golf ball 2 that achieves a desired trajectory height and desired flight duration at a high launch angle the run after landing is long.
  • the golf ball 2 that achieves a desired trajectory height and desired flight duration at a high launch angle is preferable.
  • the core 4 having an outer-hard/inner-soft structure can contribute to a high launch angle and a low spin rate as described above.
  • the golf ball 2 including the core 4 has excellent flight performance.
  • the difference DH is preferably not less than 20 and particularly preferably not less than 25. In light of ease of producing the core 4 , the difference DH is preferably not greater than 50 and particularly preferably not greater than 45.
  • the central hardness Ho is preferably not less than 30, more preferably not less than 35, and particularly preferably not less than 40.
  • the hardness Ho is preferably not greater than 70, more preferably not greater than 65, and particularly preferably not greater than 60.
  • the hardness Ho is measured with a Shore C type hardness scale mounted to an automated hardness meter (trade name “digi test II” manufactured by Heinrich Bareiss für Anlagenbau GmbH).
  • the hardness scale is pressed against the central point of the cross-section of a hemisphere obtained by cutting the golf ball 2 .
  • the measurement is conducted in an environment of 23° C.
  • the surface hardness Hs is preferably not less than 70, more preferably not less than 72, and particularly preferably not less than 74. In light of durability of the golf ball 2 , the hardness Hs is preferably not greater than 90, more preferably not greater than 88, and particularly preferably not greater than 86.
  • the hardness Hs is measured with a Shore C type hardness scale mounted to an automated hardness meter (trade name “digi test II” manufactured by Heinrich Bareiss für Anlagenbau GmbH).
  • the hardness scale is pressed against the surface of the core 4 .
  • the measurement is conducted in an environment of 23° C.
  • the mid layer 6 is positioned between the core 4 and the cover 8 .
  • the mid layer 6 is formed from a thermoplastic resin composition.
  • the base polymer of the resin composition include ionomer resins, thermoplastic polyester elastomers, thermoplastic polyamide elastomers, thermoplastic polyurethane elastomers, thermoplastic polyolefin elastomers, and thermoplastic polystyrene elastomers.
  • Ionomer resins are particularly preferable. Ionomer resins are highly elastic.
  • the golf ball 2 that includes the mid layer 6 including an ionomer resin has excellent resilience performance.
  • an ionomer resin and another resin may be used in combination.
  • the ionomer resin is included as the principal component of the base polymer.
  • the proportion of the ionomer resin to the entire base polymer is preferably not less than 50% by weight, more preferably not less than 70% by weight, and particularly preferably not less than 85% by weight.
  • preferable ionomer resins include binary copolymers formed with an ⁇ -olefin and an ⁇ , ⁇ -unsaturated carboxylic acid having 3 to 8 carbon atoms.
  • a preferable binary copolymer includes 80% by weight or more but 90% by weight or less of an ⁇ -olefin, and 10% by weight or more but 20% by weight or less of an ⁇ , ⁇ -unsaturated carboxylic acid.
  • the binary copolymer has excellent resilience performance.
  • Examples of other preferable ionomer resins include ternary copolymers formed with: an ⁇ -olefin; an ⁇ , ⁇ -unsaturated carboxylic acid having 3 to 8 carbon atoms; and an ⁇ , ⁇ -unsaturated carboxylate ester having 2 to 22 carbon atoms.
  • a preferable ternary copolymer includes 70% by weight or more but 85% by weight or less of an ⁇ -olefin, 5% by weight or more but 30% by weight or less of an ⁇ , ⁇ -unsaturated carboxylic acid, and 1% by weight or more but 25% by weight or less of an ⁇ , ⁇ -unsaturated carboxylate ester.
  • the ternary copolymer has excellent resilience performance.
  • preferable ⁇ -olefins are ethylene and propylene, while preferable ⁇ , ⁇ -unsaturated carboxylic acids are acrylic acid and methacrylic acid.
  • a particularly preferable ionomer resin is a copolymer formed with ethylene and acrylic acid.
  • Another particularly preferable ionomer resin is a copolymer formed with ethylene and methacrylic acid.
  • some of the carboxyl groups are neutralized with metal ions.
  • metal ions for use in neutralization include sodium ion, potassium ion, lithium ion, zinc ion, calcium ion, magnesium ion, aluminum ion, and neodymium ion.
  • the neutralization may be carried out with two or more types of metal ions.
  • Particularly suitable metal ions in light of resilience performance and durability of the golf ball 2 are sodium ion, zinc ion, lithium ion, and magnesium ion.
  • ionomer resins include trade names “Himilan 1555”, “Himilan 1557”, “Himilan 1605”, “Himilan 1706”, “Himilan 1707”, “Himilan 1856”, “Himilan 1855”, “Himilan AM7311”, “Himilan AM7315”, “Himilan AM7317”, “Himilan AM7329”, and “Himilan AM7337”, manufactured by Du Pont-MITSUI POLYCHEMICALS Co., Ltd.; trade names “Surlyn 6120”, “Surlyn 6910”, “Surlyn 7930”, “Surlyn 7940”, “Surlyn 8140”, “Surlyn 8150”, “Surlyn 8940”, “Surlyn 8945”, “Surlyn 9120”, “Surlyn 9150”, “Surlyn 9910”, “Surlyn 9945”, “Surlyn AD8546”, “HPF1000”, and “HPF2000”, manufactured by E.I.
  • IOTEK 7010 du Pont de Nemours and Company
  • IOTEK 7030 trade names “IOTEK 7510”, “IOTEK 7520”, “IOTEK 8000”, and “IOTEK 8030”, manufactured by ExxonMobil Chemical Corporation.
  • Two or more ionomer resins may be used in combination.
  • the resin composition of the mid layer 6 may include a styrene block-containing thermoplastic elastomer.
  • the styrene block-containing thermoplastic elastomer includes a polystyrene block as a hard segment, and a soft segment.
  • a typical soft segment is a diene block.
  • Examples of compounds for the diene block include butadiene, isoprene, 1,3-pentadiene, and 2,3-dimethyl-1,3-butadiene. Butadiene and isoprene are preferable. Two or more compounds may be used in combination.
  • styrene block-containing thermoplastic elastomers examples include styrene-butadiene-styrene block copolymers (SBS), styrene-isoprene-styrene block copolymers (SIS), styrene-isoprene-butadiene-styrene block copolymers (SIBS), hydrogenated SBS, hydrogenated SIS, and hydrogenated SIBS.
  • hydrogenated SBS include styrene-ethylene-butylene-styrene block copolymers (SEBS).
  • hydrogenated SIS examples include styrene-ethylene-propylene-styrene block copolymers (SEPS).
  • SIBS styrene-ethylene-ethylene-propylene-styrene block copolymers
  • the content of the styrene component in the styrene block-containing thermoplastic elastomer is preferably not less than 10% by weight, more preferably not less than 12% by weight, and particularly preferably not less than 15% by weight.
  • the content is preferably not greater than 50% by weight, more preferably not greater than 47% by weight, and particularly preferably not greater than 45% by weight.
  • styrene block-containing thermoplastic elastomers include an alloy of an olefin and one or more members selected from the group consisting of SBS, SIS, SIBS, SEBS, SEPS, and SEEPS.
  • the olefin component in the alloy is presumed to contribute to improvement of compatibility with another base polymer.
  • the alloy can contribute to the resilience performance of the golf ball 2 .
  • An olefin having 2 to 10 carbon atoms is preferable.
  • suitable olefins include ethylene, propylene, butene, and pentene. Ethylene and propylene are particularly preferable.
  • polymer alloys include trade names “RABALON T3221C”, “RABALON T3339C”, “RABALON SJ4400N”, “RABALON SJ5400N”, “RABALON SJ6400N”, “RABALON SJ7400N”, “RABALON SJ8400N”, “RABALON SJ9400N”, and “RABALON SR04”, manufactured by Mitsubishi Chemical Corporation.
  • styrene block-containing thermoplastic elastomers include trade name “Epofriend A1010” manufactured by Daicel Chemical Industries, Ltd., and trade name “SEPTON HG-252” manufactured by Kuraray Co., Ltd.
  • the proportion of the styrene block-containing thermoplastic elastomer to the entire base polymer is preferably not less than 1% by weight and particularly preferably not less than 2% by weight. In light of spin suppression, this proportion is preferably not greater than 20% by weight, more preferably not greater than 15% by weight, and particularly preferably not greater than 10% by weight.
  • the resin composition of the mid layer 6 may include a filler for the purpose of specific gravity adjustment and the like.
  • suitable fillers include zinc oxide, barium sulfate, calcium carbonate, and magnesium carbonate.
  • the resin composition may include powder of a metal with a high specific gravity. Specific examples of metals with a high specific gravity include tungsten and molybdenum. The amount of the filler is determined as appropriate so that the intended specific gravity of the mid layer 6 is accomplished.
  • the resin composition may include a coloring agent, crosslinked rubber powder, or synthetic resin powder. When the hue of the golf ball 2 is white, a typical coloring agent is titanium dioxide.
  • the mid layer 6 preferably has a hardness Hm of not less than 54. With the golf ball 2 including the mid layer 6 having a hardness Hm of not less than 54, a spin rate upon a shot with a driver is reduced.
  • the mid layer 6 can contribute to the flight performance of the golf ball 2 .
  • the hardness Hm is more preferably not less than 57 and particularly preferably not less than 60.
  • the hardness Hm is preferably not greater than 80, more preferably not greater than 75, and particularly preferably not greater than 72.
  • the hardness Hm of the mid layer 6 is measured according to the standards of “ASTM-D 2240-68”.
  • the hardness Hm is measured with a Shore D type hardness scale mounted to an automated hardness meter (trade name “digi test II” manufactured by Heinrich Bareiss für Anlagen GmbH).
  • a sheet that is formed by hot press is formed from the same material as that of the mid layer 6 , and has a thickness of about 2 mm is used. Prior to the measurement, a sheet is kept at 23° C. for two weeks. At the measurement, three sheets are stacked.
  • the mid layer 6 has a Shore C hardness Hmc of preferably not less than 83, more preferably not less than 86, and particularly preferably not less than 90.
  • the hardness Hmc is preferably not greater than 95.
  • the Shore C hardness Hmc of the mid layer 6 is measured with a Shore C type hardness scale mounted to an automated hardness meter (trade name “digi test II” manufactured by Heinrich Bareiss für Anlagenbau GmbH).
  • a sheet that is formed by hot press is formed from the same material as that of the mid layer 6 , and has a thickness of about 2 mm is used. Prior to the measurement, a sheet is kept at 23° C. for two weeks. At the measurement, three sheets are stacked.
  • the mid layer 6 preferably has a thickness Tm of not less than 0.3 mm and not greater than 2.5 mm.
  • the thickness Tm is more preferably not less than 0.5 mm and particularly preferably not less than 0.8 mm.
  • the thickness Tm is more preferably not greater than 2.0 mm and particularly preferably not greater than 1.8 mm. The thickness Tm is measured at a position immediately below the land 12 .
  • the golf ball 2 may include two or more mid layers 6 positioned between the core 4 and the cover 8 .
  • each mid layer 6 preferably has a thickness within the above range.
  • the cover 8 is the outermost layer except the mark layer and the paint layer.
  • the cover 8 is formed from a resin composition.
  • the base polymer of the resin composition include polyurethanes, ionomer resins, polyesters, polyamides, polyolefins, and polystyrenes.
  • a preferable base polymer in light of controllability upon an approach shot is a polyurethane.
  • the proportion of the polyurethane to the entire base resin is preferably not less than 50% by weight, more preferably not less than 60% by weight, and particularly preferably not less than 70% by weight.
  • the resin composition of the cover 8 may include a thermoplastic polyurethane or may include a thermosetting polyurethane.
  • the thermoplastic polyurethane is preferable.
  • the thermoplastic polyurethane includes a polyurethane component as a hard segment, and a polyester component or a polyether component as a soft segment.
  • the thermoplastic polyurethane is flexible.
  • the cover 8 in which the polyurethane is used has excellent scuff resistance.
  • the thermoplastic polyurethane has a urethane bond within the molecule.
  • the urethane bond can be formed by reacting a polyol with a polyisocyanate.
  • the polyol as a material for the urethane bond, has a plurality of hydroxyl groups. Low-molecular-weight polyols and high-molecular-weight polyols can be used.
  • low-molecular-weight polyols examples include diols, triols, tetraols, and hexaols.
  • diols include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, dipropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2,3-dimethyl-2,3-butanediol, neopentyl glycol, pentanediol, hexanediol, heptanediol, octanediol, and 1,6-cyclohexanedimethylol.
  • triols include glycerin, trimethylol propane, and hexanetriol.
  • tetraols include pentaerythritol and sorbitol.
  • high-molecular-weight polyols examples include polyether polyols such as polyoxyethylene glycol (PEG), polyoxypropylene glycol (PPG), and polytetramethylene ether glycol (PTMG); condensed polyester polyols such as polyethylene adipate (PEA), polybutylene adipate (PBA), and polyhexamethylene adipate (PHMA); lactone polyester polyols such as poly- ⁇ -caprolactone (PCL); polycarbonate polyols such as polyhexamethylene carbonate; and acrylic polyols. Two or more polyols may be used in combination.
  • PEG polyoxyethylene glycol
  • PPG polyoxypropylene glycol
  • PTMG polytetramethylene ether glycol
  • condensed polyester polyols such as polyethylene adipate (PEA), polybutylene adipate (PBA), and polyhexamethylene adipate (PHMA)
  • lactone polyester polyols such as
  • the high-molecular-weight polyol has a number average molecular weight of preferably not less than 400 and more preferably not less than 1000.
  • the number average molecular weight is preferably not greater than 10000.
  • polyisocyanates as a material for the urethane bond, include aromatic diisocyanates, alicyclic diisocyanates, and aliphatic diisocyanates. Two or more types of diisocyanates may be used in combination.
  • aromatic diisocyanates examples include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4′-diphenylmethane diisocyanate (MDI), 1,5-naphthylene diisocyanate (NDI), 3,3′-bitolylene-4,4′-diisocyanate (TODI), xylylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), and paraphenylene diisocyanate (PPDI).
  • MDI 1,5-naphthylene diisocyanate
  • TODI 3,3′-bitolylene-4,4′-diisocyanate
  • XDI xylylene diisocyanate
  • TMXDI tetramethylxylylene diisocyanate
  • PPDI paraphenylene diisocyanate
  • aliphatic diisocyanates is
  • alicyclic diisocyanates examples include 4,4′-dicyclohexylmethane diisocyanate (H 12 MDI), 1,3-bis(isocyanatemethyl)cyclohexane (H 6 XDI), isophorone diisocyanate (IPDI), and trans-1,4-cyclohexane diisocyanate (CHDI). 4,4′-dicyclohexylmethane diisocyanate is preferable.
  • thermoplastic polyurethane examples include trade names “Elastollan NY80A”, “Elastollan NY82A”, “Elastollan NY84A”, “Elastollan NY85A”, “Elastollan NY88A”, “Elastollan NY90A”, “Elastollan NY95A”, “Elastollan NY97A”, “Elastollan NY585”, and “Elastollan KP016N”, manufactured by BASF Japan Ltd.; and trade names “RESAMINE P4585LS” and “RESAMINE PS62490”, manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.
  • the resin composition of the cover 8 may include a coloring agent, a filler, a dispersant, an antioxidant, an ultraviolet absorber, a light stabilizer, a fluorescent material, a fluorescent brightener, and the like in an adequate amount.
  • a typical coloring agent is titanium dioxide.
  • the cover 8 has a Shore D hardness He of preferably not less than 15, more preferably not less than 18, and particularly preferably not less than 20.
  • the hardness He is preferably not greater than 40, more preferably not greater than 36, and particularly preferably not greater than 33.
  • the hardness He of the cover 8 is measured according to the standards of “ASTM-D 2240-68”.
  • the hardness He is measured with a Shore D type hardness scale mounted to an automated hardness meter (trade name “digi test II” manufactured by Heinrich Bareiss für Anlagen GmbH).
  • a sheet that is formed by hot press is formed from the same material as that of the cover 8 , and has a thickness of about 2 mm is used. Prior to the measurement, a sheet is kept at 23° C. for two weeks. At the measurement, three sheets are stacked.
  • the cover 8 has a thickness Tc of preferably not less than 0.1 mm, more preferably not less than 0.3 mm, and particularly preferably not less than 0.4 mm.
  • the thickness Tc is preferably not greater than 2.0 mm, more preferably not greater than 1.5 mm, and particularly preferably not greater than 1.0 mm. The thickness Tc is measured at a position immediately below the land 12 .
  • the cover 8 For forming the cover 8 , known methods such as injection molding, compression molding, and the like can be used. When forming the cover 8 , the dimples 10 are formed by pimples formed on the cavity face of a mold.
  • the golf ball 2 may include a reinforcing layer between the mid layer 6 and the cover 8 .
  • the reinforcing layer firmly adheres to the mid layer 6 and also to the cover 8 .
  • the reinforcing layer suppresses separation of the mid layer 6 from the cover 8 .
  • the reinforcing layer is formed from a resin composition. Examples of a preferable base polymer of the reinforcing layer include two-component curing type epoxy resins and two-component curing type urethane resins.
  • the golf ball 2 preferably has an amount of compressive deformation Sb of not less than 2.0 mm and not greater than 3.8 mm.
  • the golf ball 2 having an amount of compressive deformation Sb of not less than 2.0 mm has excellent controllability upon an approach shot.
  • the amount of compressive deformation Sb is preferably not less than 2.2 mm and particularly preferably not less than 2.3 mm.
  • the golf ball 2 having an amount of compressive deformation Sb of not greater than 3.8 mm has excellent flight performance upon a shot with a driver.
  • the amount of compressive deformation Sb is more preferably not greater than 3.5 mm and particularly preferably not greater than 3.2 mm.
  • a YAMADA type compression tester For measurement of the amount of compressive deformation Sb, a YAMADA type compression tester is used. In the tester, the golf ball 2 is placed on a hard plate made of metal. Next, a cylinder made of metal gradually descends toward the golf ball 2 . The golf ball 2 , squeezed between the bottom face of the cylinder and the hard plate, becomes deformed. A migration distance of the cylinder, starting from the state in which an initial load of 98 N is applied to the golf ball 2 up to the state in which a final load of 1274 N is applied thereto, is measured. A moving speed of the cylinder until the initial load is applied is 0.83 mm/s. A moving speed of the cylinder after the initial load is applied until the final load is applied is 1.67 mm/s.
  • the Shore C hardness Hmc of the mid layer 6 is greater than the Shore C hardness Hs at the surface of the core 4 .
  • the sphere consisting of the core 4 and the mid layer 6 has an outer-hard/inner-soft structure.
  • spin is suppressed.
  • a high launch angle is obtained.
  • the sphere has excellent flight performance.
  • the difference (Hmc ⁇ Hs) between the hardness Hmc and the hardness Hs is preferably not less than 5, more preferably not less than 8, and particularly preferably not less than 10.
  • the difference (Hmc ⁇ Hs) is preferably not greater than 30, more preferably not greater than 25, and particularly preferably not greater than 20.
  • the Shore D hardness He of the cover 8 is less than the Shore D hardness Hm of the mid layer 6 .
  • a high spin rate is obtained.
  • the golf ball 2 has excellent controllability upon an approach shot.
  • the difference (Hm ⁇ Hc) between the hardness Hm and the hardness He is preferably not less than 20, more preferably not less than 25, and particularly preferably not less than 30.
  • the difference (Hm ⁇ Hc) is preferably not greater than 50, more preferably not greater than 45, and particularly preferably not greater than 42.
  • V 1 ( DH*Hm )/( Hc*Tc )
  • the golf ball 2 satisfies the following mathematical formula (i).
  • the value V 1 correlates with the spin rate upon a shot with a driver.
  • the golf ball 2 that satisfies the mathematical formula (i)
  • the spin upon a shot with a driver is suppressed.
  • the golf ball 2 has excellent flight performance upon a short with a driver.
  • the value V 1 is more preferably not less than 100 and particularly preferably not less than 105. In light of feel at impact, the value V 1 is preferably not greater than 140.
  • a value V 2 calculated by the following mathematical formula exceeds 0.60.
  • V 2 (( Sb*Tc )/( Hc*Hm*Tm ))*1000)
  • the golf ball 2 satisfies the following mathematical formula (ii).
  • the value V 2 correlates with the feel at impact upon a shot with a driver.
  • the golf ball 2 that satisfies the mathematical formula (ii)
  • soft feel at impact is obtained upon a shot with a driver.
  • the value V 2 is more preferably not less than 0.70 and particularly preferably not less than 0.80. In light of flight performance, the value V 2 is preferably not greater than 1.20.
  • each dimple 10 is circular.
  • the golf ball 2 has dimples A each having a diameter of 4.40 mm; dimples B each having a diameter of 4.30 mm; dimples C each having a diameter of 4.15 mm; dimples D each having a diameter of 3.90 mm; and dimples E each having a diameter of 3.00 mm.
  • the number of types of the dimples 10 is five.
  • the golf ball 2 may have non-circular dimples instead of the circular dimples 10 or together with the circular dimples 10 .
  • the number of the dimples A is 60; the number of the dimples B is 158; the number of the dimples C is 72; the number of the dimples D is 36; and the number of the dimples E is 12.
  • the total number of the dimples 10 is 338. A dimple pattern is formed by these dimples 10 and the land 12 .
  • FIG. 4 shows a cross section of the golf ball 2 along a plane passing through the central point of the dimple 10 and the central point of the golf ball 2 .
  • the top-to-bottom direction is the depth direction of the dimple 10 .
  • a chain double-dashed line 14 indicates a phantom sphere 14 .
  • the surface of the phantom sphere 14 is the surface of the golf ball 2 when it is postulated that no dimple 10 exists.
  • the diameter of the phantom sphere 14 is equal to the diameter of the golf ball 2 .
  • the dimple 10 is recessed from the surface of the phantom sphere 14 .
  • the land 12 coincides with the surface of the phantom sphere 14 .
  • the cross-sectional shape of each dimple 10 is substantially a circular arc. The curvature radius of this circular arc is shown by reference character CR in FIG. 4 .
  • an arrow Dm indicates the diameter of the dimple 10 .
  • the diameter Dm is the distance between two tangent points Ed appearing on a tangent line Tg that is drawn tangent to the far opposite ends of the dimple 10 .
  • Each tangent point Ed is also the edge of the dimple 10 .
  • the edge Ed defines the contour of the dimple 10 .
  • the diameter Dm of each dimple 10 is preferably not less than 2.0 mm and not greater than 6.0 mm.
  • the dimple 10 having a diameter Dm of not less than 2.0 mm contributes to turbulization.
  • the golf ball 2 having the dimples 10 has excellent flight performance. From this viewpoint, the diameter Dm is more preferably not less than 2.5 mm and particularly preferably not less than 2.8 mm.
  • the dimple 10 having a diameter Dm of not greater than 6.0 mm does not impair a fundamental feature of the golf ball 2 being substantially a sphere. From this viewpoint, the diameter Dm is more preferably not greater than 5.5 mm and particularly preferably not greater than 5.0 mm.
  • a circular dimple 10 having the same area as that of the non-circular dimple is assumed.
  • the diameter of the assumed circular dimple 10 can be regarded as the diameter of the non-circular dimple.
  • a double ended arrow Dp 1 indicates a first depth of the dimple 10 .
  • the first depth Dp 1 is the distance between the deepest part of the dimple 10 and the surface of the phantom sphere 14 .
  • a double ended arrow Dp 2 indicates a second depth of the dimple 10 .
  • the second depth Dp 2 is the distance between the deepest part of the dimple 10 and the tangent line Tg.
  • the first depth Dp 1 of each dimple 10 is preferably not less than 0.10 mm, more preferably not less than 0.13 mm, and particularly preferably not less than 0.15 mm. In light of suppression of dropping of the golf ball 2 during flight, the first depth Dp 1 is preferably not greater than 0.65 mm, more preferably not greater than 0.60 mm, and particularly preferably not greater than 0.55 mm.
  • the area S of the dimple 10 is the area of a region surrounded by the contour line of the dimple 10 when the central point of the golf ball 2 is viewed at infinity. In the case of a circular dimple 10 , the area S is calculated by the following mathematical formula.
  • each dimple A is 15.20 mm 2 ; the area of each dimple B is 14.52 mm 2 ; the area of each dimple C is 13.53 mm 2 ; the area of each dimple D is 11.95 mm 2 ; and the area of each dimple E is 7.07 mm 2 .
  • the ratio of the sum of the areas S of all the dimples 10 relative to the surface area of the phantom sphere 14 is referred to as an occupation ratio.
  • the occupation ratio is preferably not less than 78%, more preferably not less than 80%, and particularly preferably not less than 82%.
  • the occupation ratio is preferably not greater than 95%.
  • the total area of the dimples 10 is 4695.4 mm 2 .
  • the surface area of the phantom sphere 14 of the golf ball 2 is 5728 mm 2 , so that the occupation ratio is 82.0%.
  • the total number N of the dimples 10 is preferably not less than 250, more preferably not less than 280, and particularly preferably not less than 300. From the viewpoint that each dimple 10 can contribute to turbulization, the total number N of the dimples 10 is preferably not greater than 450, more preferably not greater than 400, and particularly preferably not greater than 380.
  • the “volume V of the dimple” means the volume of a portion surrounded by the surface of the phantom sphere 14 and the surface of the dimple 10 .
  • the total volume TV of the dimples 10 is preferably not less than 450 mm 3 and not greater than 750 mm 3 .
  • the total volume TV is more preferably not less than 480 mm 3 and particularly preferably not less than 500 mm 3 .
  • the total volume TV is more preferably not greater than 730 mm 3 and particularly preferably not greater than 710 mm 3 .
  • the golf ball 2 according to the present invention has an excellent aerodynamic characteristic.
  • the following steps (a) to (h) are executed:
  • FIG. 5 is a schematic diagram for explaining this evaluation method.
  • FIG. 5 shows the phantom sphere 14 of the golf ball 2 .
  • reference character NP represents a north pole.
  • the north pole NP corresponds to the top of a cavity face formed by an upper mold half for molding the golf ball 2 .
  • Reference character SP represents a south pole.
  • the south pole SP corresponds to the deepest part of a cavity face formed by a lower mold half for molding the golf ball 2 .
  • Reference character Eq represents an equator.
  • the phantom sphere 14 can be divided into a northern hemisphere NH and a southern hemisphere SH by the equator Eq.
  • the latitude of the north pole NP is 90° (degrees).
  • the latitude ⁇ of the equator Eq is zero.
  • the latitude of the south pole SP is ⁇ 90°.
  • the counterclockwise direction when the phantom sphere 14 is seen from the north pole NP is a positive direction of longitude ⁇ .
  • the minimum value of ⁇ is zero.
  • the maximum value of ⁇ is 360°.
  • the spherical polar coordinates of a point present on the surface of the phantom sphere 14 are represented by ( ⁇ , ⁇ ). In FIG. 5 , a point (0, 0) is located in the front.
  • reference character Loa represents a first longitude line.
  • the longitude ⁇ of the first longitude line Loa is 0° and also 360°.
  • the phantom sphere 14 has numerous longitude lines.
  • a longitude line that contains the maximum number of dimples 10 that centrally intersect the longitude line is defined as the first longitude line Loa.
  • the longitude line passes through the area center of gravity of the dimple 10 .
  • a first axis Ax 1 is assumed.
  • the first axis Ax 1 passes through a point Pn 1 and a point Ps 1 .
  • the point Pn 1 and the point Ps 1 are present on the surface of the phantom sphere 14 .
  • the point Pn 1 is present on the northern hemisphere NH.
  • the coordinates of the point Pn 1 are (75, 270).
  • the point Ps 1 is present on the southern hemisphere SH.
  • the coordinates of the point Ps 1 are ( ⁇ 75, 90).
  • the first axis Ax 1 is tilted relative to the earth axis. The angle of the tilt is 15°.
  • the earth axis is a line passing through the north pole NP and the south pole SP.
  • a first great circle GC 1 that is present on the surface of the phantom sphere 14 of the golf ball 2 is assumed.
  • the first axis Ax 1 is orthogonal to the first great circle GC 1 .
  • the first axis Ax 1 is orthogonal to the plane including the first great circle GC 1 .
  • the first great circle GC 1 is tilted relative to the equator Eq. The angle of the tilt is 15°.
  • the great circle is a circle that is present on the surface of the phantom sphere 14 and has a diameter equal to the diameter of the phantom sphere 14 .
  • the golf ball 2 rotates about the first axis Ax 1 . During this rotation, the circumferential speed of the first great circle GC 1 is high. Therefore, the surface roughness of the golf ball 2 at and near the first great circle GC 1 greatly influences the flight performance of the golf ball 2 .
  • FIG. 6 shows these small circles C 1 and C 2 .
  • Each small circle is parallel to the first great circle GC 1 .
  • FIG. 7 schematically shows a partial cross section of the golf ball 2 in FIG. 6 .
  • FIG. 7 shows a cross-section passing through the center O of the golf ball 2 .
  • the right-left direction in FIG. 7 is the direction of the first axis Ax 1 .
  • the absolute value of the central angle between the small circle C 1 and the first great circle GC 1 is 30°.
  • the absolute value of the central angle between the small circle C 2 and the first great circle GC 1 is also 30°.
  • the golf ball 2 is divided at the small circles C 1 and C 2 , and of the surface of the golf ball 2 , a region sandwiched between the small circles C 1 and C 2 is defined. Since the circumferential speed of the first great circle GC 1 is high, the dimples 10 present in this region greatly influence the aerodynamic characteristic of the golf ball 2 .
  • a point P( ⁇ ) is the point that is located on the surface of the golf ball 2 and of which the central angle with the first great circle GC 1 is ⁇ ° (degrees).
  • a point F( ⁇ ) is the foot of a perpendicular line Pe( ⁇ ) that extends downward from the point P( ⁇ ) to the first axis Ax 1 .
  • An arrow L 1 ( ⁇ ) represents the length of the perpendicular line Pe( ⁇ ). In other words, the length L 1 ( ⁇ ) is the distance between the point P( ⁇ ) and the first axis Ax 1 . For one cross section, the lengths L 1 ( ⁇ ) are calculated at 21 points P( ⁇ ).
  • the lengths L 1 ( ⁇ ) are calculated at angles ⁇ of ⁇ 30 ⁇ , ⁇ 27°, ⁇ 24°, ⁇ 21°, ⁇ 18°, ⁇ 15°, ⁇ 12°, ⁇ 9°, ⁇ 6°, ⁇ 3°, 0°, 3°, 6°, 9°, 12°, 15°, 18°, 21°, 24°, 27°, and 30°.
  • the 21 lengths L 1 ( ⁇ ) are summed, thereby obtaining a total length L 2 (mm).
  • the total length L 2 is a parameter dependent on the surface shape in the cross section shown in FIG. 7 .
  • FIG. 8 shows a partial cross section of the golf ball 2 .
  • a direction perpendicular to the surface of the sheet is the direction of the first axis Ax 1 .
  • reference character ⁇ represents a rotation angle of the golf ball 2 .
  • the rotation angles ⁇ are set at an interval of an angle of 0.25°.
  • the total length L 2 is calculated.
  • 1440 total lengths L 2 are obtained along the rotation direction.
  • These total lengths L 2 are a data constellation calculated through one rotation of the golf ball 2 . This data constellation is calculated on the basis of 30240 lengths L 1 .
  • FIG. 9 shows a graph plotting the data constellation, for the first axis Ax 1 , of the golf ball 2 shown in FIGS. 2 and 3 .
  • the horizontal axis represents the rotation angle ⁇
  • the vertical axis represents the total length L 2 .
  • the above mathematical formula is a combination of two trigonometric functions having different periods.
  • a n and b n are Fourier coefficients.
  • the magnitude of each component to be combined is determined depending on these Fourier coefficients.
  • Each coefficient is represented by the following mathematical formula.
  • N is the total number of pieces of data of the data constellation
  • F k is the kth value in the data constellation.
  • the spectrum is represented by the following mathematical formula.
  • FIG. 10 shows a graph plotting the transformed data constellation.
  • the horizontal axis represents an order
  • the vertical axis represents an amplitude.
  • the maximum peak is determined.
  • the peak value Pd 1 of the maximum peak and the order Fd 1 of the maximum peak are determined.
  • the peak value Pd 1 and the order Fd 1 are numeric values representing the aerodynamic characteristic during rotation about the first axis Ax 1 .
  • the peak value Pd 1 is 270.2 mm
  • the order Fd 1 is 33.
  • FIG. 11 also shows the phantom sphere 14 of the golf ball 2 .
  • FIG. 11 shows the equator Eq and the longitude line Loa having a longitude ⁇ of zero.
  • the point (0, 0) is located in the front.
  • reference character Ax 2 represents a second axis.
  • the second axis Ax 2 passes through a point Pn 2 and a point Ps 2 .
  • the point Pn 2 and the point Ps 2 are present on the surface of the phantom sphere 14 .
  • the coordinates of the point Pn 2 are (60, 270).
  • the coordinates of the point Ps 2 are ( ⁇ 60, 90).
  • the second axis Ax 2 is tilted relative to the earth axis. The angle of the tilt is 30°.
  • FIG. 11 shows a second great circle GC 2 that is present on the surface of the phantom sphere 14 of the golf ball 2 and to which the second axis Ax 2 is orthogonal.
  • the second great circle GC 2 is tilted relative to the equator Eq.
  • the angle of the tilt is 30°.
  • an aerodynamic characteristic is evaluated by the same method as that for rotation about the first axis Ax 1 .
  • two small circles C 1 and C 2 are assumed.
  • the absolute value of the central angle between the small circle C 1 and the second great circle GC 2 is 30°.
  • the absolute value of the central angle between the small circle C 2 and the second great circle GC 2 is also 30°.
  • 1440 total lengths L 2 are calculated.
  • a data constellation for the second axis Ax 2 is calculated. Fourier transformation is performed on this data constellation, thereby obtaining a transformed data constellation.
  • the peak value Pd 2 of the maximum peak and the order Fd 2 of the maximum peak are determined.
  • the peak value Pd 2 and the order Fd 2 are numeric values representing the aerodynamic characteristic during rotation about the second axis Ax 2 .
  • the peak value Pd 2 is 177.9 mm
  • the order Fd 2 is 37.
  • FIG. 12 also shows the phantom sphere 14 of the golf ball 2 .
  • FIG. 12 shows the equator Eq and the longitude line Loa having a longitude 1 of zero.
  • the point (0, 0) is located in the front.
  • reference character Ax 3 represents a third axis.
  • the third axis Ax 3 passes through a point Pn 3 and a point Ps 3 .
  • the point Pn 3 and the point Ps 3 are present on the surface of the phantom sphere 14 .
  • the coordinates of the point Pn 3 are (45, 270).
  • the coordinates of the point Ps 3 are ( ⁇ 45, 90).
  • the third axis Ax 3 is tilted relative to the earth axis. The angle of the tilt is 45°.
  • FIG. 12 shows a third great circle GC 3 that is present on the surface of the phantom sphere 14 of the golf ball 2 and to which the third axis Ax 3 is orthogonal.
  • the third great circle GC 3 is tilted relative to the equator Eq. The angle of the tilt is 45°.
  • an aerodynamic characteristic is evaluated by the same method as that for rotation about the first axis Ax 1 .
  • two small circles C 1 and C 2 are assumed.
  • the absolute value of the central angle between the small circle C 1 and the third great circle GC 3 is 30°.
  • the absolute value of the central angle between the small circle C 2 and the third great circle GC 3 is also 30°.
  • 1440 total lengths L 2 are calculated.
  • a data constellation for the third axis Ax 3 is calculated. Fourier transformation is performed on this data constellation, thereby obtaining a transformed data constellation.
  • the peak value Pd 3 of the maximum peak and the order Fd 3 of the maximum peak are determined.
  • the peak value Pd 3 and the order Fd 3 are numeric values representing the aerodynamic characteristic during rotation about the third axis Ax 3 .
  • the peak value Pd 3 is 150.2 mm
  • the order Fd 3 is 37.
  • FIG. 13 also shows the phantom sphere 14 of the golf ball 2 .
  • FIG. 13 shows the equator Eq and the longitude line Loa having a longitude ⁇ of zero.
  • the point (0, 0) is located in the front.
  • reference character Ax 4 represents a fourth axis.
  • the fourth axis Ax 4 passes through a point Pn 4 and a point Ps 4 .
  • the point Pn 4 and the point Ps 4 are present on the surface of the phantom sphere 14 .
  • the coordinates of the point Pn 4 are (30, 270).
  • the coordinates of the point Ps 4 are ( ⁇ 30, 90).
  • the fourth axis Ax 4 is tilted relative to the earth axis. The angle of the tilt is 60°.
  • FIG. 13 shows a fourth great circle GC 4 that is present on the surface of the phantom sphere 14 of the golf ball 2 and to which the fourth axis Ax 4 is orthogonal.
  • the fourth great circle GC 4 is tilted relative to the equator Eq. The angle of the tilt is 60°.
  • an aerodynamic characteristic is evaluated by the same method as that for rotation about the first axis Ax 1 .
  • two small circles C 1 and C 2 are assumed.
  • the absolute value of the central angle between the small circle C 1 and the fourth great circle GC 4 is 30°.
  • the absolute value of the central angle between the small circle C 2 and the fourth great circle GC 4 is also 30°.
  • 1440 total lengths L 2 are calculated.
  • a data constellation for the fourth axis Ax 4 is calculated. Fourier transformation is performed on this data constellation, thereby obtaining a transformed data constellation.
  • the peak value Pd 4 of the maximum peak and the order Fd 4 of the maximum peak are determined.
  • the peak value Pd 4 and the order Fd 4 are numeric values representing the aerodynamic characteristic during rotation about the fourth axis Ax 4 .
  • the peak value Pd 4 is 316.4 mm
  • the order Fd 4 is 34.
  • FIG. 14 also shows the phantom sphere 14 of the golf ball 2 .
  • FIG. 14 shows the equator Eq and the longitude line Loa having a longitude ⁇ of zero.
  • the point (0, 0) is located in the front.
  • reference character Ax 5 represents a fifth axis.
  • the fifth axis Ax 5 passes through a point Pn 5 and a point Ps 5 .
  • the point Pn 5 and the point Ps 5 are present on the surface of the phantom sphere 14 .
  • the coordinates of the point Pn 5 are (15, 270).
  • the coordinates of the point Ps 5 are ( ⁇ 15, 90).
  • the fifth axis Ax 5 is tilted relative to the earth axis. The angle of the tilt is 75°.
  • FIG. 14 shows a fifth great circle GC 5 that is present on the surface of the phantom sphere 14 of the golf ball 2 and to which the fifth axis Ax 5 is orthogonal.
  • the fifth great circle GC 5 is tilted relative to the equator Eq. The angle of the tilt is 75°.
  • an aerodynamic characteristic is evaluated by the same method as that for rotation about the first axis Ax 1 .
  • two small circles C 1 and C 2 are assumed.
  • the absolute value of the central angle between the small circle C 1 and the fifth great circle GC 5 is 30°.
  • the absolute value of the central angle between the small circle C 2 and the fifth great circle GC 5 is also 30°.
  • 1440 total lengths L 2 are calculated.
  • a data constellation for the fifth axis Ax 5 is calculated. Fourier transformation is performed on this data constellation, thereby obtaining a transformed data constellation.
  • the peak value Pd 5 of the maximum peak and the order Fd 5 of the maximum peak are determined.
  • the peak value Pd 5 and the order Fd 5 are numeric values representing the aerodynamic characteristic during rotation about the fifth axis Ax 5 .
  • the peak value Pd 5 is 190.0 mm
  • the order Fd 5 is 27.
  • FIG. 15 also shows the phantom sphere 14 of the golf ball 2 .
  • FIG. 15 shows the equator Eq and a longitude line Lob having a longitude ⁇ of 90°.
  • a point (0, 90) is located in the front.
  • reference character Ax 6 represents a sixth axis.
  • the sixth axis Ax 6 passes through a point Pn 6 and a point Ps 6 .
  • the point Pn 6 and the point Ps 6 are present on the surface of the phantom sphere 14 .
  • the coordinates of the point Pn 6 are (75, 0).
  • the coordinates of the point Ps 6 are ( ⁇ 75, 180).
  • the sixth axis Ax 6 is tilted relative to the earth axis. The angle of the tilt is 150.
  • FIG. 15 shows a sixth great circle GC 6 that is present on the surface of the phantom sphere 14 of the golf ball 2 and to which the sixth axis Ax 6 is orthogonal.
  • the sixth great circle GC 6 is tilted relative to the equator Eq. The angle of the tilt is 15°.
  • an aerodynamic characteristic is evaluated by the same method as that for rotation about the first axis Ax 1 .
  • two small circles C 1 and C 2 are assumed.
  • the absolute value of the central angle between the small circle C 1 and the sixth great circle GC 6 is 30°.
  • the absolute value of the central angle between the small circle C 2 and the sixth great circle GC 6 is also 30°.
  • 1440 total lengths L 2 are calculated.
  • a data constellation for the sixth axis Ax 6 is calculated. Fourier transformation is performed on this data constellation, thereby obtaining a transformed data constellation.
  • the peak value Pd 6 of the maximum peak and the order Fd 6 of the maximum peak are determined.
  • the peak value Pd 6 and the order Fd 6 are numeric values representing the aerodynamic characteristic during rotation about the sixth axis Ax 6 .
  • the peak value Pd 6 is 270.2 mm, and the order Fd 6 is 33.
  • FIG. 16 also shows the phantom sphere 14 of the golf ball 2 .
  • FIG. 16 shows the equator Eq and the longitude line Lob having a longitude ⁇ of 90°.
  • the point (0, 90) is located in the front.
  • reference character Ax 7 represents a seventh axis.
  • the seventh axis Ax 7 passes through a point Pn 7 and a point Ps 7 .
  • the point Pn 7 and the point Ps 7 are present on the surface of the phantom sphere 14 .
  • the coordinates of the point Pn 7 are (60, 0).
  • the coordinates of the point Ps 7 are ( ⁇ 60, 180).
  • the seventh axis Ax 7 is tilted relative to the earth axis. The angle of the tilt is 30°.
  • FIG. 16 shows a seventh great circle GC 7 that is present on the surface of the phantom sphere 14 of the golf ball 2 and to which the seventh axis Ax 7 is orthogonal.
  • the seventh great circle GC 7 is tilted relative to the equator Eq.
  • the angle of the tilt is 30°.
  • an aerodynamic characteristic is evaluated by the same method as that for rotation about the first axis Ax 1 .
  • two small circles C 1 and C 2 are assumed.
  • the absolute value of the central angle between the small circle C 1 and the seventh great circle GC 7 is 30°.
  • the absolute value of the central angle between the small circle C 2 and the seventh great circle GC 7 is also 30°.
  • 1440 total lengths L 2 are calculated.
  • a data constellation for the seventh axis Ax 7 is calculated. Fourier transformation is performed on this data constellation, thereby obtaining a transformed data constellation.
  • the peak value Pd 7 of the maximum peak and the order Fd 7 of the maximum peak are determined.
  • the peak value Pd 7 and the order Fd 7 are numeric values representing the aerodynamic characteristic during rotation about the seventh axis Ax 7 .
  • the peak value Pd 7 is 177.9 mm
  • the order Fd 7 is 37.
  • FIG. 17 also shows the phantom sphere 14 of the golf ball 2 .
  • FIG. 17 shows the equator Eq and the longitude line Lob having a longitude of 90°.
  • the point (0, 90) is located in the front.
  • reference character Ax 8 represents an eighth axis.
  • the eighth axis Ax 8 passes through a point Pn 8 and a point Ps 8 .
  • the point Pn 8 and the point Ps 8 are present on the surface of the phantom sphere 14 .
  • the coordinates of the point Pn 8 are (45, 0).
  • the coordinates of the point Ps 8 are ( ⁇ 45, 180).
  • the eighth axis Ax 8 is tilted relative to the earth axis. The angle of the tilt is 45°.
  • FIG. 17 shows an eighth great circle GC 8 that is present on the surface of the phantom sphere 14 of the golf ball 2 and to which the eighth axis Ax 8 is orthogonal.
  • the eighth great circle GC 8 is tilted relative to the equator Eq. The angle of the tilt is 45°.
  • an aerodynamic characteristic is evaluated by the same method as that for rotation about the first axis Ax 1 .
  • two small circles C 1 and C 2 are assumed.
  • the absolute value of the central angle between the small circle C 1 and the eighth great circle GC 8 is 30°.
  • the absolute value of the central angle between the small circle C 2 and the eighth great circle GC 8 is also 30°.
  • 1440 total lengths L 2 are calculated.
  • a data constellation for the eighth axis Ax 8 is calculated. Fourier transformation is performed on this data constellation, thereby obtaining a transformed data constellation.
  • the peak value Pd 8 of the maximum peak and the order Fd 8 of the maximum peak are determined.
  • the peak value Pd 8 and the order Fd 8 are numeric values representing the aerodynamic characteristic during rotation about the eighth axis Ax 8 .
  • the peak value Pd 8 is 150.2 mm
  • the order Fd 8 is 37.
  • FIG. 18 also shows the phantom sphere 14 of the golf ball 2 .
  • FIG. 18 shows the equator Eq and the longitude line Lob having a longitude ⁇ of 90°.
  • the point (0, 90) is located in the front.
  • reference character Ax 9 represents a ninth axis.
  • the ninth axis Ax 9 passes through a point Pn 9 and a point Ps 9 .
  • the point Pn 9 and the point Ps 9 are present on the surface of the phantom sphere 14 .
  • the coordinates of the point Pn 9 are (30, 0).
  • the coordinates of the point Ps 9 are ( ⁇ 30, 180).
  • the ninth axis Ax 9 is tilted relative to the earth axis. The angle of the tilt is 60°.
  • FIG. 18 shows a ninth great circle GC 9 that is present on the surface of the phantom sphere 14 of the golf ball 2 and to which the ninth axis Ax 9 is orthogonal.
  • the ninth great circle GC 9 is tilted relative to the equator Eq. The angle of the tilt is 60°.
  • an aerodynamic characteristic is evaluated by the same method as that for rotation about the first axis Ax 1 .
  • two small circles C 1 and C 2 are assumed.
  • the absolute value of the central angle between the small circle C 1 and the ninth great circle GC 9 is 30°.
  • the absolute value of the central angle between the small circle C 2 and the ninth great circle GC 9 is also 30°.
  • 1440 total lengths L 2 are calculated.
  • a data constellation for the ninth axis Ax 9 is calculated. Fourier transformation is performed on this data constellation, thereby obtaining a transformed data constellation.
  • the peak value Pd 9 of the maximum peak and the order Fd 9 of the maximum peak are determined.
  • the peak value Pd 9 and the order Fd 9 are numeric values representing the aerodynamic characteristic during rotation about the ninth axis Ax 9 .
  • the peak value Pd 9 is 316.4 mm
  • the order Fd 9 is 34.
  • FIG. 19 also shows the phantom sphere 14 of the golf ball 2 .
  • FIG. 19 shows the equator Eq and the longitude line Lob having a longitude ⁇ of 90°.
  • the point (0, 90) is located in the front.
  • reference character Ax 10 represents a tenth axis.
  • the tenth axis Ax 10 passes through a point Pn 10 and a point Ps 10 .
  • the point Pn 10 and the point Ps 10 are present on the surface of the phantom sphere 14 .
  • the coordinates of the point Pn 10 are (15, 0).
  • the coordinates of the point Ps 10 are ( ⁇ 15, 180).
  • the tenth axis Ax 10 is tilted relative to the earth axis. The angle of the tilt is 75°.
  • FIG. 19 shows a tenth great circle GC 10 that is present on the surface of the phantom sphere 14 of the golf ball 2 and to which the tenth axis Ax 10 is orthogonal.
  • the tenth great circle GC 10 is tilted relative to the equator Eq. The angle of the tilt is 75°.
  • an aerodynamic characteristic is evaluated by the same method as that for rotation about the first axis Ax 1 .
  • two small circles C 1 and C 2 are assumed.
  • the absolute value of the central angle between the small circle C 1 and the tenth great circle GC 10 is 30°.
  • the absolute value of the central angle between the small circle C 2 and the tenth great circle GC 10 is also 30°.
  • 1440 total lengths L 2 are calculated. In other words, a data constellation for the tenth axis Ax 10 is calculated.
  • the peak value Pd 10 of the maximum peak and the order Fd 10 of the maximum peak are determined.
  • the peak value Pd 10 and the order Fd 10 are numeric values representing the aerodynamic characteristic during rotation about the tenth axis Ax 10 .
  • the peak value Pd 10 is 190.0 mm
  • the order Fd 10 is 27.
  • FIG. 20 also shows the phantom sphere 14 of the golf ball 2 .
  • FIG. 20 shows the equator Eq and a longitude line Loc having a longitude of 180°.
  • a point (0, 180) is located in the front.
  • reference character Ax 11 represents an eleventh axis.
  • the eleventh axis Ax 11 passes through a point Pn 11 and a point Ps 11 .
  • the point Pn 11 and the point Ps 11 are present on the surface of the phantom sphere 14 .
  • the coordinates of the point Pn 11 are (75, 90).
  • the coordinates of the point Ps 11 are ( ⁇ 75, 270).
  • the eleventh axis Ax 11 is tilted relative to the earth axis. The angle of the tilt is 15°.
  • FIG. 20 shows an eleventh great circle GC 11 that is present on the surface of the phantom sphere 14 of the golf ball 2 and to which the eleventh axis Ax 11 is orthogonal.
  • the eleventh great circle GC 11 is tilted relative to the equator Eq. The angle of the tilt is 15°.
  • an aerodynamic characteristic is evaluated by the same method as that for rotation about the first axis Ax 1 .
  • two small circles C 1 and C 2 are assumed.
  • the absolute value of the central angle between the small circle C 1 and the eleventh great circle GC 11 is 30°.
  • the absolute value of the central angle between the small circle C 2 and the eleventh great circle GC 11 is also 30°.
  • 1440 total lengths L 2 are calculated. In other words, a data constellation for the eleventh axis Ax 11 is calculated.
  • the peak value Pd 11 of the maximum peak and the order Fd 11 of the maximum peak are determined.
  • the peak value Pd 11 and the order Fd 11 are numeric values representing the aerodynamic characteristic during rotation about the eleventh axis Ax 11 .
  • the peak value Pd 11 is 270.2 mm, and the order Fd 11 is 33.
  • FIG. 21 also shows the phantom sphere 14 of the golf ball 2 .
  • FIG. 21 shows the equator Eq and the longitude line Loc having a longitude of 180°.
  • the point (0, 180) is located in the front.
  • reference character Ax 12 represents a twelfth axis.
  • the twelfth axis Ax 12 passes through a point Pn 12 and a point Ps 12 .
  • the point Pn 12 and the point Ps 12 are present on the surface of the phantom sphere 14 .
  • the coordinates of the point Pn 12 are (60, 90).
  • the coordinates of the point Ps 12 are ( ⁇ 60, 270).
  • the twelfth axis Ax 12 is tilted relative to the earth axis. The angle of the tilt is 30°.
  • FIG. 21 shows a twelfth great circle GC 12 that is present on the surface of the phantom sphere 14 of the golf ball 2 and to which the twelfth axis Ax 12 is orthogonal.
  • the twelfth great circle GC 12 is tilted relative to the equator Eq. The angle of the tilt is 30°.
  • an aerodynamic characteristic is evaluated by the same method as that for rotation about the first axis Ax 1 .
  • two small circles C 1 and C 2 are assumed.
  • the absolute value of the central angle between the small circle C 1 and the twelfth great circle GC 12 is 30°.
  • the absolute value of the central angle between the small circle C 2 and the twelfth great circle GC 12 is also 30°.
  • 1440 total lengths L 2 are calculated. In other words, a data constellation for the twelfth axis Ax 12 is calculated.
  • the peak value Pd 12 of the maximum peak and the order Fd 12 of the maximum peak are determined.
  • the peak value Pd 12 and the order Fd 12 are numeric values representing the aerodynamic characteristic during rotation about the twelfth axis Ax 12 .
  • the peak value Pd 12 is 177.9 mm
  • the order Fd 12 is 37.
  • FIG. 22 also shows the phantom sphere 14 of the golf ball 2 .
  • FIG. 22 shows the equator Eq and the longitude line Loc having a longitude p of 180°.
  • the point (0, 180) is located in the front.
  • reference character Ax 13 represents a thirteenth axis.
  • the thirteenth axis Ax 13 passes through a point Pn 13 and a point Ps 13 .
  • the point Pn 13 and the point Ps 13 are present on the surface of the phantom sphere 14 .
  • the coordinates of the point Pn 13 are (45, 90).
  • the coordinates of the point Ps 13 are ( ⁇ 45, 270).
  • the thirteenth axis Ax 13 is tilted relative to the earth axis. The angle of the tilt is 45°.
  • FIG. 22 shows a thirteenth great circle GC 13 that is present on the surface of the phantom sphere 14 of the golf ball 2 and to which the thirteenth axis Ax 13 is orthogonal.
  • the thirteenth great circle GC 13 is tilted relative to the equator Eq. The angle of the tilt is 45°.
  • an aerodynamic characteristic is evaluated by the same method as that for rotation about the first axis Ax 1 .
  • two small circles C 1 and C 2 are assumed.
  • the absolute value of the central angle between the small circle C 1 and the thirteenth great circle GC 13 is 30°.
  • the absolute value of the central angle between the small circle C 2 and the thirteenth great circle GC 13 is also 30°.
  • 1440 total lengths L 2 are calculated. In other words, a data constellation for the thirteenth axis Ax 13 is calculated.
  • the peak value Pd 13 of the maximum peak and the order Fd 13 of the maximum peak are determined.
  • the peak value Pd 13 and the order Fd 13 are numeric values representing the aerodynamic characteristic during rotation about the thirteenth axis Ax 13 .
  • the peak value Pd 13 is 150.2 mm
  • the order Fd 13 is 37.
  • FIG. 23 also shows the phantom sphere 14 of the golf ball 2 .
  • FIG. 23 shows the equator Eq and the longitude line Loc having a longitude ⁇ of 180°.
  • the point (0, 180) is located in the front.
  • reference character Ax 14 represents a fourteenth axis.
  • the fourteenth axis Ax 14 passes through a point Pn 14 and a point Ps 14 .
  • the point Pn 14 and the point Ps 14 are present on the surface of the phantom sphere 14 .
  • the coordinates of the point Pn 14 are (30, 90).
  • the coordinates of the point Ps 14 are ( ⁇ 30, 270).
  • the fourteenth axis Ax 14 is tilted relative to the earth axis. The angle of the tilt is 60°.
  • FIG. 23 shows a fourteenth great circle GC 14 that is present on the surface of the phantom sphere 14 of the golf ball 2 and to which the fourteenth axis Ax 14 is orthogonal.
  • the fourteenth great circle GC 14 is tilted relative to the equator Eq. The angle of the tilt is 60°.
  • an aerodynamic characteristic is evaluated by the same method as that for rotation about the first axis Ax 1 .
  • two small circles C 1 and C 2 are assumed.
  • the absolute value of the central angle between the small circle C 1 and the fourteenth great circle GC 14 is 30°.
  • the absolute value of the central angle between the small circle C 2 and the fourteenth great circle GC 14 is also 30°.
  • 1440 total lengths L 2 are calculated. In other words, a data constellation for the fourteenth axis Ax 14 is calculated.
  • the peak value Pd 14 of the maximum peak and the order Fd 14 of the maximum peak are determined.
  • the peak value Pd 14 and the order Fd 14 are numeric values representing the aerodynamic characteristic during rotation about the fourteenth axis Ax 14 .
  • the peak value Pd 14 is 316.4 mm
  • the order Fd 14 is 34.
  • FIG. 24 also shows the phantom sphere 14 of the golf ball 2 .
  • FIG. 24 shows the equator Eq and the longitude line Loc having a longitude ⁇ of 180°.
  • the point (0, 180) is located in the front.
  • reference character Ax 15 represents a fifteenth axis.
  • the fifteenth axis Ax 15 passes through a point Pn 15 and a point Ps 15 .
  • the point Pn 15 and the point Ps 15 are present on the surface of the phantom sphere 14 .
  • the coordinates of the point Pn 15 are (15, 90).
  • the coordinates of the point Ps 15 are ( ⁇ 15, 270).
  • the fifteenth axis Ax 15 is tilted relative to the earth axis. The angle of the tilt is 75°.
  • FIG. 24 shows a fifteenth great circle GC 15 that is present on the surface of the phantom sphere 14 of the golf ball 2 and to which the fifteenth axis Ax 15 is orthogonal.
  • the fifteenth great circle GC 15 is tilted relative to the equator Eq. The angle of the tilt is 75°.
  • an aerodynamic characteristic is evaluated by the same method as that for rotation about the first axis Ax 1 .
  • two small circles C 1 and C 2 are assumed.
  • the absolute value of the central angle between the small circle C 1 and the fifteenth great circle GC 15 is 30°.
  • the absolute value of the central angle between the small circle C 2 and the fifteenth great circle GC 15 is also 30°.
  • 1440 total lengths L 2 are calculated. In other words, a data constellation for the fifteenth axis Ax 15 is calculated.
  • the peak value Pd 15 of the maximum peak and the order Fd 15 of the maximum peak are determined.
  • the peak value Pd 15 and the order Fd 15 are numeric values representing the aerodynamic characteristic during rotation about the fifteenth axis Ax 15 .
  • the peak value Pd 15 is 190.0 mm
  • the order Fd 15 is 27.
  • the minimums among the 15 peak values (Pd 1 to Pd 15 ) are Pd 3 , Pd 8 , and Pd 13 .
  • the minimum value of the peak value Pd is 150.2 mm.
  • the minimum value is preferably not less than 95 mm.
  • the minimum value of the peak value Pd is more preferably not less than 120 mm and particularly preferably not less than 140 mm.
  • the maximums among the 15 peak values (Pd 1 to Pd 15 ) are Pd 4 , Pd 9 , and Pd 14 .
  • the maximum value of the peak value Pd is 316.4 mm. According to the findings by the present inventor, the maximum value is preferably not greater than 500 mm.
  • the golf ball 2 in which the maximum value is not greater than 500 mm has an excellent aerodynamic characteristic.
  • the golf ball 2 has a large flight distance. From this viewpoint, the maximum value of the peak value Pd is more preferably not greater than 400 mm and particularly preferably not greater than 330 mm.
  • the average of the 15 peak values (Pd 1 to Pd 15 ) is preferably not less than 200 mm.
  • the golf ball 2 in which the average is not less than 200 mm has an excellent aerodynamic characteristic.
  • the golf ball 2 has a large flight distance.
  • the average is more preferably not less than 210 mm and particularly preferably not less than 220 mm.
  • the average is preferably not greater than 300 mm and particularly preferably not greater than 230 mm. In the present embodiment, the average is 220.9 mm.
  • the minimums among the 15 orders (Fd 1 to Fd 15 ) are Fd 5 , Fd 10 , and Fd 15 .
  • the minimum value of the order Fd is 27. According to the findings by the present inventor, the minimum value is preferably not less than 27.
  • the golf ball 2 in which the minimum value is not less than 27 has an excellent aerodynamic characteristic.
  • the golf ball 2 has a large flight distance.
  • the maximums among the 15 orders (Fd 1 to Fd 15 ) are Fd 2 , Fd 3 , Fd 7 , Fd 8 , Fd 12 , and Fd 13 .
  • the maximum value of the order Fd is 37. According to the findings by the present inventor, the maximum value is preferably not greater than 37.
  • the golf ball 2 in which the maximum value is not greater than 37 has an excellent aerodynamic characteristic.
  • the golf ball 2 has a large flight distance.
  • the average of the 15 orders is preferably not less than 30 and not greater than 34.
  • the golf ball 2 in which the average falls within this range has an excellent aerodynamic characteristic.
  • the golf ball 2 has a large flight distance. In the present embodiment, the average is 33.6.
  • the golf ball 2 is evaluated by the 15 peak values Pd and the 15 orders Fd based on the 15 axes Ax.
  • the aerodynamic characteristic of the golf ball 2 can be objectively evaluated.
  • a rubber composition B was obtained by kneading 100 parts by weight of a high-cis polybutadiene (trade name “BR-730”, manufactured by JSR Corporation), 29.5 parts by weight of zinc diacrylate, 5 parts by weight of zinc oxide, an appropriate amount of barium sulfate, 0.9 parts by weight of dicumyl peroxide, 0.3 parts by weight of pentabromo diphenyl disulfide, 0.1 parts by weight of 2-naphthalenethiol, and 2.0 parts by weight of benzoic acid.
  • the rubber composition B was placed into a mold including upper and lower mold halves each having a hemispherical cavity, and heated at 150° C. for 20 minutes to obtain a core with a diameter of 39.7 mm.
  • a resin composition M1 was obtained by kneading 47 parts by weight of an ionomer resin (the aforementioned “Himilan 1605”), 50 parts by weight of another ionomer resin (the aforementioned “Himilan AM7329”), 3 parts by weight of a styrene block-containing thermoplastic elastomer (the aforementioned “RABALON T3221C”), and 4 parts by weight of titanium dioxide with a twin-screw kneading extruder.
  • the core was covered with the resin composition M1 by injection molding to form a mid layer with a thickness of 1.0 mm.
  • a paint composition (trade name “POLIN 750LE”, manufactured by SHINTO PAINT CO., LTD.) including a two-component curing type epoxy resin as a base polymer was prepared.
  • the base material liquid of this paint composition includes 30 parts by weight of a bisphenol A type epoxy resin and 70 parts by weight of a solvent.
  • the curing agent liquid of this paint composition includes 40 parts by weight of a modified polyamide amine, 55 parts by weight of a solvent, and 5 parts by weight of titanium dioxide.
  • the weight ratio of the base material liquid to the curing agent liquid is 1/1.
  • This paint composition was applied to the surface of the mid layer with a spray gun, and kept at 23° C. for 12 hours to obtain a reinforcing layer with a thickness of 10 ⁇ m.
  • a resin composition C1 was obtained by kneading 100 parts by weight of a thermoplastic polyurethane elastomer (the aforementioned “Elastollan NY80A”), 0.2 parts by weight of a light stabilizer (trade name “TINUVIN 770”), and 4 parts by weight of titanium dioxide with a twin-screw kneading extruder.
  • Half shells were obtained from the resin composition C1 by compression molding. The sphere consisting of the core, the mid layer, and the reinforcing layer was covered with two of these half shells.
  • FIG. 2 is a plan view of the golf ball
  • FIG. 3 is a front view of the golf ball.
  • Examples 4 to 8 were obtained in the same manner as Example 1, except the specifications of the core, the mid layer, and the cover were as shown in Table 12 below.
  • the specifications of the core are shown in detail in Table 1 below.
  • the specifications of the mid layer are shown in detail in Table 2 below.
  • the specifications of the cover are shown in detail in Table 3 below.
  • a rubber composition A was obtained by kneading 100 parts by weight of a high-cis polybutadiene (the aforementioned “BR-730”), 35 parts by weight of magnesium acrylate, 28 parts by weight of methacrylic acid, an appropriate amount of barium sulfate, and 1.3 parts by weight of dicumyl peroxide.
  • the rubber composition A was placed into a mold including upper and lower mold halves each having a hemispherical cavity, and heated at 160° C. for 20 minutes to obtain a center with a diameter of 15.0 mm. The amount of barium sulfate was adjusted such that a center having a predetermined weight was obtained.
  • a rubber composition C was obtained by kneading 100 parts by weight of a high-cis polybutadiene (the aforementioned “BR-730”), 33.0 parts by weight of zinc diacrylate, 5 parts by weight of zinc oxide, an appropriate amount of barium sulfate, 0.9 parts by weight of dicumyl peroxide, and 0.3 parts by weight of pentabromo diphenyl disulfide.
  • Half shells were formed from the rubber composition C. The center was covered with two of the half shells. The center and the half shells were placed into a mold including upper and lower mold halves each having a hemispherical cavity, and heated at 160° C. for 20 minutes to obtain a core with a diameter of 39.7 mm. The amount of barium sulfate was adjusted such that a core having a predetermined weight was obtained.
  • a resin composition M1 was obtained by kneading 47 parts by weight of an ionomer resin (the aforementioned “Himilan 1605”), 50 parts by weight of another ionomer resin (the aforementioned “Himilan AM7329”), 3 parts by weight of a styrene block-containing thermoplastic elastomer (the aforementioned “RABALON T3221C”), and 4 parts by weight of titanium dioxide with a twin-screw kneading extruder.
  • the core was covered with the resin composition M1 by injection molding to form a mid layer with a thickness of 1.0 mm.
  • a paint composition (trade name “POLIN 750LE”, manufactured by SHINTO PAINT CO., LTD.) including a two-component curing type epoxy resin as a base polymer was prepared.
  • the base material liquid of this paint composition includes 30 parts by weight of a bisphenol A type epoxy resin and 70 parts by weight of a solvent.
  • the curing agent liquid of this paint composition includes 40 parts by weight of a modified polyamide amine, 55 parts by weight of a solvent, and 5 parts by weight of titanium dioxide.
  • the weight ratio of the base material liquid to the curing agent liquid is 1/1.
  • This paint composition was applied to the surface of the mid layer with a spray gun, and kept at 23° C. for 12 hours to obtain a reinforcing layer with a thickness of 10 ⁇ m.
  • a resin composition C1 was obtained by kneading 100 parts by weight of a thermoplastic polyurethane elastomer (the aforementioned “Elastollan NY80A”), 0.2 parts by weight of a light stabilizer (trade name “TINUVIN 770”), and 4 parts by weight of titanium dioxide with a twin-screw kneading extruder.
  • Half shells were obtained from the resin composition C1 by compression molding. The sphere consisting of the core, the mid layer, and the reinforcing layer was covered with two of these half shells.
  • a clear paint including a two-component curing type polyurethane as a base material was applied to this cover to obtain a golf ball of Example 9 with a diameter of about 42.7 mm and a weight of about 45.6 g.
  • Dimple specifications I of the golf ball are shown in detail in Tables 4, 6, and 8 below.
  • a golf ball of Comparative Example 12 was obtained in the same manner as Example 9, except the specifications of the dimples were as shown in Table 14 below.
  • the specifications of the dimples are shown in detail in Tables 5, 7, and 9 below.
  • a driver (trade name “SRIXON Z-TX”, manufactured by DUNLOP SPORTS CO. LTD., shaft hardness: X, loft angle: 8.5°) was attached to a swing machine manufactured by Golf Laboratories, Inc.
  • a golf ball was hit under a condition of a head speed of 50 m/sec, and the ball speed, the spin rate, and the flight distance were measured.
  • the flight distance is the distance between the point at the hit and the point at which the ball stopped.
  • Tables 10 to 14 The average value of data obtained from 12 measurements is shown in Tables 10 to 14 below.
  • a sand wedge (trade name “XXIO”, manufactured by DUNLOP SPORTS CO. LTD., shaft hardness: R, loft angle: 56°) was attached to a swing machine manufactured by Golf Laboratories, Inc. A golf ball was hit under a condition of a head speed of 21 m/sec, and the spin rate was measured. The average value of data obtained from 12 measurements is shown in Tables 10 to 14 below.
  • the golf ball of each Example has excellent flight performance upon a shot with a driver and excellent controllability upon an approach shot. From the results of evaluation, advantages of the present invention are clear.
  • the golf ball according to the present invention is suitable for, for example, playing golf on golf courses and practicing at driving ranges.
  • the above descriptions are merely illustrative examples, and various modifications can be made without departing from the principles of the present invention.

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Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030100387A1 (en) * 2001-09-05 2003-05-29 Akira Kato Multi-piece solid golf ball
US6659889B2 (en) * 2001-07-27 2003-12-09 Bridgestone Sports Co., Ltd. Golf ball
US20040009831A1 (en) * 2002-07-12 2004-01-15 Keiji Ohama Multi-piece solid golf ball
US6679791B2 (en) * 2000-06-26 2004-01-20 Bridgestone Sports Co., Ltd. Golf ball
US7090592B2 (en) * 2004-05-04 2006-08-15 Bridgestone Sports Co., Ltd. Multi-piece solid golf ball
US20060252579A1 (en) * 2005-05-04 2006-11-09 Bridgestone Sports Co., Ltd. Three-piece solid golf ball
US7841954B2 (en) * 2001-10-05 2010-11-30 Sri Sports Limited Multi-piece solid golf ball
US20100326175A1 (en) * 2009-06-30 2010-12-30 Hyoungchol Kim Golf ball
US20110034274A1 (en) * 2009-08-05 2011-02-10 Takahiro Sajima Golf ball
US20120004053A1 (en) * 2010-06-30 2012-01-05 Hyoungchol Kim Designing method for dimple pattern of golf ball
US20120322584A1 (en) * 2011-06-17 2012-12-20 Bridgestone Sports Co., Ltd. Method for arranging dimples on golf ball surface
US20140171222A1 (en) * 2012-12-17 2014-06-19 Bridgestone Sports Co., Ltd Multi-piece solid golf ball
US20140171221A1 (en) * 2012-12-17 2014-06-19 Bridgestone Sports Co., Ltd. Multi-piece solid golf ball

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6478628B2 (ja) * 2014-12-26 2019-03-06 住友ゴム工業株式会社 ゴルフボール及びその製造方法。
JP6442279B2 (ja) * 2014-12-26 2018-12-19 住友ゴム工業株式会社 ゴルフボール
JP6819265B2 (ja) * 2016-12-14 2021-01-27 住友ゴム工業株式会社 ゴルフボール

Patent Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6679791B2 (en) * 2000-06-26 2004-01-20 Bridgestone Sports Co., Ltd. Golf ball
US6659889B2 (en) * 2001-07-27 2003-12-09 Bridgestone Sports Co., Ltd. Golf ball
US20030100387A1 (en) * 2001-09-05 2003-05-29 Akira Kato Multi-piece solid golf ball
US7841954B2 (en) * 2001-10-05 2010-11-30 Sri Sports Limited Multi-piece solid golf ball
US20040009831A1 (en) * 2002-07-12 2004-01-15 Keiji Ohama Multi-piece solid golf ball
US7090592B2 (en) * 2004-05-04 2006-08-15 Bridgestone Sports Co., Ltd. Multi-piece solid golf ball
US20060252579A1 (en) * 2005-05-04 2006-11-09 Bridgestone Sports Co., Ltd. Three-piece solid golf ball
US20100326175A1 (en) * 2009-06-30 2010-12-30 Hyoungchol Kim Golf ball
US20110034274A1 (en) * 2009-08-05 2011-02-10 Takahiro Sajima Golf ball
US20120004053A1 (en) * 2010-06-30 2012-01-05 Hyoungchol Kim Designing method for dimple pattern of golf ball
US20120322584A1 (en) * 2011-06-17 2012-12-20 Bridgestone Sports Co., Ltd. Method for arranging dimples on golf ball surface
US20140171222A1 (en) * 2012-12-17 2014-06-19 Bridgestone Sports Co., Ltd Multi-piece solid golf ball
US20140171221A1 (en) * 2012-12-17 2014-06-19 Bridgestone Sports Co., Ltd. Multi-piece solid golf ball

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Rick White, Hardness Conversion, uploaded 7/25/18, Thermal Tech Equipment, 1 page *

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