TW201442763A - Golf ball - Google Patents

Abstract

The golf ball is provided with multiple first dimples (1) formed on the surface and multiple second dimples (2), which are formed on the surface around the multiple first dimples (1) and have a diameter smaller than the multiple first dimples (1). The ratio of the depth to the diameter for each of the multiple second dimples is 0.050 or more, and the ratio of the diameter of each of the multiple second dimples (2) with respect to the largest diameter (D1) of the multiple first dimples (1) is 0.21 to 0.41. It is thereby possible to obtain a golf ball with which extreme decreases in lift coefficient in the low speed range can be limited while improving lift coefficient in all speed ranges.

Description

golf

The present invention relates to golf balls, and more particularly to golf balls having dimples formed on their surfaces.

It is known that various dimples are formed on the surface of a golf ball for the purpose of improving flight performance. It is well known that a golf ball having a properly designed dimple can fly better than a golf ball having a smooth spherical surface without a dimple. Deliberately adjusting the resistance and lift in the flight of the golf ball by the number, shape, and plural combinations of dimples is well known to those of ordinary skill in the art to which the present invention pertains. For the purpose of improving the efficiency of the dimple, for example, the following proposals are made.

In the Japanese Patent Publication No. 62-192181 (Patent Document 1), a golf ball having a large dimple and a small dimple is disclosed. This golf ball is combined with a plurality of diameter dimples for the purpose of exerting dimple effects in various speed regions. However, the diameter ratio of the largest dimple to the smallest dimple of this golf ball is quite large and will not be fully effective in all speed domains in flight.

Japanese Laid-Open Patent Publication No. Hei No. 1-223979 (Patent Document 2) discloses a golf ball having a maximum dimple diameter divided by a minimum dimple diameter and having a range of 1.68 to 2.5. In this golf ball, dimples having almost no difference in diameter are arranged in the finely divided regions, improving flight symmetry. However, in this golf ball, due to The diameter of the dimples is almost indistinguishable, and the entire velocity range in flight is not fully effective, and the contribution of this golf ball to the increase in flight distance is not sufficient.

In Japanese Laid-Open Patent Publication No. 2007-190382 (Patent Document 3), a golf ball using a plurality of types of dimples having a maximum dimple and a minimum dimple diameter is disclosed. This golf ball optimizes the radius of curvature by combining the dimples having a large diameter ratio, and can obtain the surface occupancy of the dimples, so that an increase in the flying distance can be achieved. However, in this golf ball, since the change in the air force with the speed domain is not considered, the contribution to the flight distance increase is not sufficient.

[First technical literature] [Patent Literature]

[Patent Document 1] JP-A-62-192181

[Patent Document 2] Japanese Patent Publication No. 1-22979

[Patent Document 3] JP-A-2007-190382

For the average golfer, in order to achieve an increase in flight distance, high trajectory is preferred. In order to obtain a high trajectory, a dimple having a large lift coefficient is required. The smaller the depth and the volume of the dimple, and the larger the diameter of the dimple, the larger the lift coefficient, and the golf ball is easily raised. However, once the depth and volume of the dimple are reduced, there is a tendency that the lift coefficient in the low speed range of 30 m/s or less in the second half of the flight is extremely lowered. Thereby, there is a problem that the golf ball is easily lowered without extending the flight distance after the flying apex of the golf ball.

It is difficult to expose the golf ball disclosed in each of the above publications. The lift coefficient is increased in all speed ranges, and the extreme decrease in the lift coefficient in the low speed range is suppressed.

The present invention has been made in view of the above problems, and an object thereof is to provide a golf ball which can increase the lift coefficient in all speed ranges and can suppress an extreme decrease in the lift coefficient in the low speed range.

A golf ball according to one aspect of the present invention includes: a plurality of first dimples formed on a surface; and a plurality of second dimples formed around a plurality of first dimples in the surface and having less than a plurality of first dimples The diameter of the dimple. The ratio of the depth to the diameter of each of the plurality of second dimples is 0.050 or more, and the ratio of the diameter of each of the plurality of second dimples to the maximum diameter of the plurality of first dimples is 0.21 or more and 0.41 or less.

Under the careful study of the inventors, it was found that the ratio of the depth to diameter of each of the plurality of second dimples is 0.050 or more, and the diameter of each of the plurality of second dimples is the largest for the plurality of first dimples. When the ratio of the diameters is 0.21 or more and 0.41 or less, the lift coefficient is increased in all the speed ranges, and the extreme decrease in the lift coefficient in the low speed range can be suppressed.

Another golf ball of the present invention comprises: a plurality of first dimples formed on a surface; and a plurality of second dimples formed around the plurality of first dimples in the surface and having less than a plurality of first dimples The diameter of the dimple. The ratio of the depth to the diameter of each of the plurality of second dimples is 0.050 or more, and the respective diameters of the plurality of second dimples are 1.0 mm or more and 1.9 mm or less.

Under the careful study of the inventors, it was found that the ratio of the depth to the diameter of each of the plurality of second dimples is 0.050 or more, and the plurality of When the respective diameters of the two dimples are 1.0 mm or more and 1.9 mm or less, the lift coefficient is increased in all the speed ranges, and the extreme decrease in the lift coefficient in the low speed range can be suppressed.

In the golf ball described above, it is preferable that the number of the plurality of second dimples is 60 or more.

In the golf ball described above, the ratio of the depth to the diameter of each of the plurality of second dimples is preferably 0.050 or more and 0.240 or less.

In the golf ball described above, the number of the plurality of second dimples is preferably 60 or more and 2,160 or less.

From the above, the inventors have found that the lift coefficient is increased in all the speed ranges, and the extreme decrease in the lift coefficient in the low speed range can be suppressed.

As described above, with the golf ball of the present invention, the lift coefficient is increased in all the speed ranges, and the extreme decrease in the lift coefficient in the low speed range can be suppressed.

1‧‧‧First dimple

2‧‧‧second dimple

3‧‧‧flat

11‧‧‧LL recess

12‧‧‧L dimple

13‧‧‧LS dimple

14‧‧‧M dimple

15‧‧‧S dimple

10‧‧‧nuclear

20‧‧ hood

A1‧‧‧The area of the first dimple

A2‧‧‧ area of the second dimple

B1‧‧‧Deep depth of the first dimple

B2‧‧‧Deep depth of the second dimple

D1‧‧‧ diameter of the first dimple

D2‧‧‧ diameter of the second dimple

V1‧‧‧ the volume of the first dimple

Volume of the second dimple of V2‧‧

Fig. 1 is a schematic front view showing a golf ball in an embodiment of the present invention.

Fig. 2 is an enlarged plan view showing a portion P of Fig. 1.

Fig. 3 is a cross-sectional view taken along line III-III of Fig. 1.

Fig. 4 is a schematic front view of a golf ball of a comparative example.

Fig. 5 is a schematic front view of the golf ball of the fourth embodiment.

Fig. 6 is a graph showing the relationship between the lift coefficient and the spin parameters of Comparative Example 1.

Fig. 7 is a graph showing the relationship between the lift coefficient and the spin parameters of Comparative Example 2.

Fig. 8 is a graph showing the relationship between the lift coefficient and the spin parameters of Comparative Example 3.

Fig. 9 is a graph showing the relationship between the lift coefficient and the spin parameters of Example 1.

Fig. 10 is a graph showing the relationship between the lift coefficient and the spin parameters of Example 2.

Fig. 11 is a graph showing the relationship between the lift coefficient and the spin parameter of Example 3.

Fig. 12 is a graph showing the relationship between the lift coefficient and the spin parameters of Example 4.

Fig. 13 is a graph showing the relationship between the lift coefficient and the spin parameters of Example 5.

Fig. 14 is a graph showing the relationship between the lift coefficient and the spin parameters of Example 6.

Fig. 15 is a view showing the relationship between the lift coefficient and the spin parameter of Example 7.

Fig. 16 is a graph showing the relationship between the lift coefficient and the spin parameters of Example 8.

Fig. 17 is a graph showing the relationship between the lift coefficient of the spin parameter of 0.1 and the depth/diameter of the second dimple in Examples 1 to 4 and Comparative Example 1.

Figure 18 is a graph showing the difference between the lift coefficient of the flow rate of 44 m/s and the lift coefficient of the flow rate of 28 m/s in the spin parameters of 0.1 and 4 and the depth/diameter of the second dimple in Examples 1 to 4 and Comparative Example 1. Diagram of the relationship.

Figure 19 is a graph showing the lift coefficients of the spin parameters of 0.1, the diameters of the respective dimples, and the plurality of first recesses of Examples 1, 5, and 7 and Comparative Examples 1 and 2. A plot of the relationship between the ratio of the maximum diameter of the litter.

Figure 20 is a graph showing the difference between the lift coefficient of the flow rate of 44 m/s at a spin parameter of 0.1 and the lift coefficient of a flow rate of 28 m/s, and the second dimple of Examples 1, 5, and 7 and Comparative Examples 1 and 2. A plot of the relationship of the respective diameters to the ratio of the maximum diameters of the plurality of first dimples.

Fig. 21 is a graph showing the relationship between the lift coefficient of the spin parameter of 0.1 and the ratio of the diameter of each of the second dimples to the maximum diameter of the plurality of first dimples in Examples 1 to 8 and Comparative Examples 1 to 3. Picture.

Fig. 22 is a graph showing the relationship between the lift coefficient of the spin parameter of 0.1 and the number of second dimples in Examples 1, 4, 6, 7, 8 and Comparative Example 1.

Figure 23 is a graph showing the difference between the lift coefficient of the flow rate of 44 m/s and the lift coefficient of the flow rate of 28 m/s in Examples 1, 4, 6, 7, 8 and Comparative Example 1, and the second concave. A diagram of the relationship between the number of nests.

Fig. 24 is a schematic cross-sectional view showing a golf ball according to an embodiment of the present invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

First, the configuration of a golf ball-related dimple pattern according to an embodiment of the present invention will be described.

The arrangement of the dimples formed on the surface of the golf ball is not particularly limited as long as good flight symmetry can be obtained. However, it is preferable to arrange the divided regions as an arrangement unit when the spherical surface is regarded as a regular polyhedron, for example, an icosahedron, a dodecahedron, an octahedron, or the like. A golf ball according to an embodiment of the present invention is divided when the spherical surface is regarded as an icosahedron The dimples formed in the triangular region are arranged as an arrangement unit.

Referring to Fig. 1, a golf ball according to an embodiment of the present invention has a plurality of first dimples 1, a plurality of second dimples 2, and a flat portion 3. A plurality of first dimples 1 and a plurality of second dimples 2 are respectively formed on the surface of the golf ball. The flat portion 3 is a portion where a plurality of first dimples 1 and a plurality of second dimples 2 are not formed.

The first dimple 1 may be formed by a dimple group having a different diameter, or may be formed by a dimple having a single diameter. In the case of combining dimples having a plurality of diameters, it is preferred to combine two or more types of dimples. When eight or more dimples are combined, a uniform alignment is not obtained, and the appearance is deteriorated. Further, the diameter of the first dimple 1 is preferably 2.5 mm or more and 6.5 mm or less. The diameter of the dimple having the largest diameter of the first dimple 1 is preferably 3.8 mm or more and 6.5 mm or less, more preferably 4.2 mm or more and 6 mm or less, and particularly preferably 4.5 mm or more and 5.5 mm or less. Excessive dimples can impede the freedom of the dimple configuration, while too small dimples are difficult to obtain a higher lift coefficient.

A golf ball according to an embodiment of the present invention is an LL dimple 11 , an L dimple 12 , an LS dimple 13 , an M dimple 14 , and an S dimple 15 having a size order of diameter as the first dimple 1 . A plurality of second dimples 2 are formed around the plurality of first dimples 1 and formed over the entire golf ball. The plurality of second dimples 2 are substantially regularly arranged. The plurality of second dimples 2 are different depending on the sphere of the spherical surface of the golf ball. The plurality of second dimples 2 are of a smaller diameter than the plurality of first dimples 1.

Here, the diameter of the plurality of second dimples 2 is preferably 0.5 mm or more and 2.0 mm or less, more preferably 0.8 mm or more and 2.0 mm or less, and particularly preferably 1.0 mm. Above, 1.9mm or less. If the diameter is less than 0.5mm, it will not be effective in the high-speed area or the low-speed area; if the diameter is larger than 2.0mm, it will affect the lift coefficient of the high-speed area, and these diameters are used to maintain the lift coefficient in the high-speed range and suppress A significant reduction in the lift coefficient in the low speed range is not suitable for the purpose of the second dimple 2.

The number of the second dimples 2 is preferably 60 or more, even if it is, for example, 1350. Further, the number of the second dimples 2 may be 2,160. The number of 2,160 as the second dimples 2 is the maximum number of the first dimples 1 within the aforementioned conditions and the second dimples 2 are formed around the first dimples 1 as the design limit. The number.

Referring to FIGS. 1 and 2, the first dimple 1 and the second dimple 2 of the golf ball according to an embodiment of the present invention are each formed in a circular shape in plan view.

Referring to Figures 1 to 3, in the section through the deepest portion of the dimple and the center of the golf ball, when the connecting line is drawn in the dimple section line, the joint between the connecting line and the cross-hatching line is called a dimple. edge. The distance between the above connecting line and the deepest part of the dimple is the depth of the dimple. The above connecting line distance between the above contacts is the diameter of the dimple. The area of the plane of the circle formed by the above contacts is the area of the dimples. The range enclosed by the plane and the dimple surface of the circle to which the contacts are connected is the volume of the dimple.

The diameter D1 of the first dimple 1 is the distance between the above-mentioned connecting line and the joint between both ends of the dimple line. The diameter D1 of the first dimple 1 is the diameter of the plane of the circle formed by the edge of the first dimple 1. The area A1 of the first dimple 1 is the area of the plane of the circle formed by the edge of the first dimple 1.

Although not shown, the LL dimples 11, the L dimples 12, the LS dimples 13, Both the M dimples 14 and the S dimples 15 have respective diameters. In other words, the LL dimple 11 has a diameter DLL, the L dimple 12 has a diameter DL, the LS dimple 13 has a diameter DLS, the M dimple 14 has a diameter DM, and the S dimple 15 has a diameter DS.

Regarding all the LL dimples 11, the total area of the area of the circle formed by the edge of the LL dimple 11 is a total area ALL. For example, the LL dimple 11 has a diameter DLL of 4.70 mm and a total area ALL of 2604 mm ² . Further, the number of LL dimples 11 is 150. The ratio of the total area ALL to the total plane area (total area) of the first dimple 1 and the second dimple 2 is 57.2% or more and 62.0% or less.

Regarding all of the L dimples 12, the total area of the area of the plane of the circle formed by the edge of the L dimple 12 is the total area AL. For example, the L dimple 12 has a diameter DL of 4.27 mm and a total area AL of 344 mm ² . Further, the number of L dimples 12 is 24. The ratio of the total area AL to the area of all the planes of the first dimple 1 and the second dimple 2 is 7.5% or more and 8.2% or less.

Regarding all of the LS dimples 13, the total area of the area of the circle formed by the edges of the LS dimples 13 is the total area ALS. For example, the LS dimple 13 has a diameter DLS of 4.06 mm and a total area ALS of 934 mm ² . Further, the number of LS dimples 13 is 72. The ratio of the total area ALS to the area of all the planes of the first dimple 1 and the second dimple 2 is 20.5% or more and 22.2% or less.

Regarding all of the M dimples 14, the total area of the area of the circle formed by the edge of the M dimple 14 is a total area AM. For example, the M dimple 14 has a diameter DM of 3.80 mm and a total area AM of 159 mm ² . Further, the number of M dimples 14 is 14. The ratio of the total area AM to the area of all the planes of the first dimple 1 and the second dimple 2 is 3.5% or more and 3.8% or less.

Regarding all of the S dimples 15, the total area AS is the sum of the areas of the planes of the circles formed by the edges of the S dimples 15. For example, the S dimple 15 has a diameter DS of 2.78 mm and a total area AS of 73 mm ² . Further, the number of S dimples 15 is twelve. The ratio of the total area AS to the area of all the planes of the first dimple 1 and the second dimple 2 is 1.6% or more and 1.7% or less.

The diameter D2 of the second dimple 2 is the distance between the above-mentioned connecting line and the joint of both ends of the dimple line. The diameter D2 of the second dimple 2 is the diameter of the plane of the circle formed by the edge of the second dimple 2. The area A2 of the second dimple 2 is the area of the plane of the circle formed by the edge of the second dimple 2.

Regarding all of the second dimples 2, the total area A2 is the total area A20. For example, the diameter D2 of the second dimple 2 is 1.04 mm or more and 1.87 mm or less, and the total area A20 is 90 mm ² or more and 440 mm ² or less. Further, the number of the second dimples 2 is 60 or more and 294 or less. The ratio of the total area A20 to the area (total area) of all the planes of the first dimple 1 and the second dimple 2 is 0.021 (2.1%) or more and 0.097 (9.7%) or less.

The diameter D2 of the second dimple 2 is, for example, 1.04 mm or more and 1.87 mm or less; the diameter DLL of the LL dimple 11 may be, for example, 4.70 mm. Therefore, the ratio of the diameter D2 of the second dimple 2 to the maximum diameter of the plurality of first dimples 1 (the diameter DLL of the LL dimple 11) is 0.22 or more and 0.40 or less.

Referring to FIG. 3, the depth B1 of the first dimple 1 is the maximum distance between the surface of the first dimple 1 and the plane of the circle formed by the edge of the first dimple 1. The volume V1 of the first dimple 1 is the volume of the space surrounded by the surface of the first dimple 1 and the plane of the circle formed by the edge portion of the first dimple 1.

The depth BLL of the LL dimple 11 is, for example, 0.148 mm. Regarding all of the LL dimples 11, the total volume VLL is the sum of the volume of the space enclosed by the surface of the LL dimple 11 and the circular plane formed by the edge of the LL dimple 11. For example, the total volume VLL is 209 mm ³ . Further, the ratio of the total volume VLL to the total volume of the first dimple 1 and the second dimple 2 is 55.9% or more and 59.2% or less.

The depth BL of the L dimple 12 is, for example, 0.178 mm. With respect to all of the L dimples 12, the total volume VL is the sum of the volume of the space enclosed by the surface of the L dimple 12 and the plane formed by the edge of the L dimple 12. For example, the total volume VL is 31 mm ³ . Further, the ratio of the total volume VL to the total volume of the first dimple 1 and the second dimple 2 is 8.3% or more and 8.8% or less.

The depth BLS of the LS dimple 13 is, for example, 0.184 mm. Regarding all of the LS dimples 13, the sum of the volume of the space enclosed by the surface of the LS dimple 13 and the plane formed by the edge of the LS dimple 13 is the total volume VLS. For example, the total volume VLS is 86 mm ³ . Further, the ratio of the total volume VLS to the total volume of the first dimple 1 and the second dimple 2 is 23.1% or more and 24.5% or less.

The depth BM of the M dimple 14 is, for example, 0.194 mm. Regarding all of the M dimples 14, the total volume VM is the sum of the volume of the space surrounded by the surface of the M dimple 14 and the plane formed by the edge of the M dimple 14. For example, the total volume VM is 16 mm ³ . Further, the ratio of the total volume VM to the total volume of the first dimple 1 and the second dimple 2 is 4.2% or more and 4.4% or less.

The depth BS of the S dimple 15 is, for example, 0.122 mm. Regarding all of the S dimples 15, the total volume VS is the sum of the volume of the space surrounded by the surface of the S dimple 15 and the plane formed by the circle formed by the edge of the S dimple 15. For example, the total volume VS is 4 mm ³ . Further, the ratio of the total volume VS to the total volume of the first dimple 1 and the second dimple 2 is 1.2% or more and 1.3% or less.

Also, the depth B2 of the second dimple 2 is the maximum distance between the surface of the second dimple 2 and the plane of the circle formed by the edge of the second dimple 2.

The volume V2 of the second dimple 2 is the volume of the space enclosed by the surface of the second dimple 2 and the plane of the circle formed by the edge of the second dimple 2.

The depth B2 of the second dimple 2 is, for example, 0.070 mm or more and 0.249 mm or less. The ratio of the depth B2 of each of the plurality of second dimples 2 to the diameter D2 is 0.051 or more and 0.239 or less. Regarding all of the second dimples 2, the total volume V2 is a total volume V20. For example, the total volume V20 or more of 6mm ^3, 27mm ³ or less. Further, the number of the second dimples 2 is 60 or more and 292 or less. The ratio of the total volume V20 to the total volume (total volume) of the first dimple 1 and the second dimple 2 is 0.018 (1.8%) or more and 0.073 (7.3%) or less.

The ratio of the total area of the plurality of first dimples 1 and the plurality of second dimples 2 to the total area of the imaginary spheres in which the first dimple 1 and the second dimple 2 are not formed is 0.734 (73.4%) or more and 0.795 ( 79.5%) below. Further, the ratio of the total volume of the plurality of first dimples 1 and the plurality of second dimples 2 to the total volume (volume) of the imaginary spheres in which the first dimple 1 and the second dimple 2 are not formed is 0.0086 (0.86%) Above, below 0.0092 (0.92%).

Next, a structure of a golf ball according to an embodiment of the present invention will be described.

Referring to Fig. 24, the golf ball has a spherical core 10 and a cover 20. However, one or more intermediate layers may be provided between the core 10 and the cover 20. Further, on the surface of the cover 20, a plurality of dimples are formed. This golf ball has a coating layer and a marking layer at the outer side of the cover 20, but these layers are omitted in the drawings.

The shape of the core 10 is generally spherical, and for example, a protrusion that equally divides the surface of the spherical core 10 may be provided, or a recess that is evenly distributed may be provided. In the case where the ridges are provided, it is preferable that the concave portion divided by the ridges is filled by a plurality of layers of the surrounding layer or a single layer of the surrounding layer covering each of the concave portions, and the core 10 and the surrounding layer are formed. The shape of the formed body is spherical. In the case where the concave portion is provided, it is preferable that the concave portion is filled with the outer layer material covering the core 10 to be formed into a spherical shape.

The diameter of the golf ball is required to be 42.67 mm or more according to the regulations (refer to R&A and USGA). However, in consideration of aerodynamic characteristics and the like, the spherical diameter is preferably as small as possible, for example, 42.7 to 43.7 mm. The weight is also required to be 45.93g or less according to the rules. The weight is preferably as heavy as possible in consideration of aerodynamic characteristics, etc., and can be formed to be 45.2 g to 45.93 g or less.

The core 10 is formed into a spherical shape and formed of a rubber composition. The diameter of the core 10 is preferably 35.0 mm to 41.0 mm, and particularly preferably 38.5 mm to 40.0 mm. If the core 10 is small, the rebound performance will decrease. If the core 10 is too large, the thickness of the cover 20 covering the core 10 will be too small to deteriorate the durability, and the ball will be soft and the rebound performance will be degraded.

The core 10 can be produced from a known rubber composition prepared by blending a base rubber, a crosslinked material, a metal salt of an unsaturated carboxylic acid, a filler, and the like. As the base rubber, natural rubber, polyisoprene rubber, styrene-butadiene rubber, EPDM, or the like can be used, but it is particularly preferable to use at least 40% or more, preferably 80% or more, for cis. 4-bonded high cis polybutadiene.

As the crosslinking agent, for example, an organic peroxide such as dicumyl peroxide or a third butyl peroxide can be used, and particularly preferably diisopropyl oxide is used. benzene.

As the metal salt of the unsaturated carboxylic acid, a metal salt of a monovalent or divalent unsaturated carboxylic acid having a carbon number of 3 to 8 such as acrylic acid or methacrylic acid is preferably used, and it is particularly preferable to use a zinc acrylate to improve the ball. The rebound performance.

As the filler, those which are usually mixed in the core can be used, and for example, zinc oxide, barium sulfate, calcium carbonate or the like can be used. Further, an organic sulfur compound, an anti-aging agent or a peptizing agent may be mixed as needed.

Further, as the material constituting the core 10, other known elastomers may be used in addition to the rubber composition described above.

The cover 20 is constructed of an elastomer. A dimple is formed on the surface thereof. The layer thickness of the cover 20 is preferably from 0.3 mm to 2.5 mm, particularly preferably from 0.8 mm to 1.8 mm.

As the material of the cover 20, for example, an ionic polymer resin, a thermoplastic elastomer containing a styrene block, a thermoplastic polyester elastomer, a thermoplastic and a thermosetting polyurethane elastomer, a thermoplastic polyamide elastomer, and a thermoplastic polyolefin elastomer. These materials can be used singly or in combination of two or more.

A particularly preferred substrate polymer is an ionic polymer resin. Preferred examples of the ionic polymer resin include a binary polymer of an α-olefin and an α,β-unsaturated carboxylic acid having 3 or more and 8 or less carbon atoms. A preferred binary polymer comprises an α-olefin having a mass percentage of 80% or more and a mass percentage of 90% or less, and an α,β-unsaturated carboxylic acid having a mass percentage of 10% or more and a mass percentage of 20% or less. This binary polymer is excellent in rebound performance. Preferred other ionic polymer resins include α-olefins and α,β-unsaturated carboxylic acids having 3 or less carbon atoms, 8 or more, and α,β-unsaturated carboxylic acid esters having 2 or more carbon atoms and 22 or less carbon atoms. Polymer. A preferred terpolymer comprises 70% by mass or more and 85% by mass or less The α-olefin, an α,β-unsaturated carboxylic acid having a mass percentage of 5% or more and a mass percentage of 30% or less, and an α,β-unsaturated carboxylic acid ester having a mass percentage of 1% or more and a mass percentage of 25% or less. This terpolymer is excellent in rebound performance. Among the binary polymer and the terpolymer, the preferred α-olefin is ethylene and propylene, and preferably the α, β-unsaturated carboxylic acid is acrylic acid and methacrylic acid. A particularly preferred ionic polymer resin is a copolymer of ethylene and acrylic acid or methacrylic acid.

Among the binary polymers and the terpolymers, a part of the carboxyl groups are neutralized by the metal ions. Metal ions used for neutralization are, for example, sodium ions, potassium ions, lithium ions, zinc ions, calcium ions, magnesium ions, aluminum ions, and barium ions. Neutralization can also be carried out with two or more metal ions. From the viewpoint of the rebound performance and durability of golf balls, the most excellent metal ions are sodium ions, zinc ions, and magnesium ions.

The cover 20 can be formed by a known method such as an injection molding method, a compression molding method, or a die casting method. When the cover is formed, a dimple is usually formed on the surface of the cover. After forming, trimming, cleaning, polishing, painting, and label printing are performed as needed to complete the golf ball.

Next, the effect of the golf ball in one embodiment of the present invention will be described.

Through intensive research by the inventors, it was found that the ratio of the depth to the diameter D2 of each of the plurality of second dimples 2 is 0.050 or more, and the diameter D2 of each of the plurality of second dimples 2 is the largest for the plurality of first dimples 1. The ratio of the diameter (diameter DLL of the LL dimple 11) is 0.21 or more and 0.41 or less, and the lift coefficient is increased in all the speed ranges, and the extreme decrease in the lift coefficient in the low speed range can be suppressed.

Moreover, the inventors have discovered that each of the plurality of second dimples 2 The ratio of the depth to the diameter D2 is 0.050 or more, and the diameter D2 of each of the plurality of second dimples 2 is 1.0 mm or more and 1.9 mm or less, and the lift coefficient is increased in all the speed ranges, and the lift coefficient in the low speed range can be suppressed. Extremely lower.

In the golf ball according to an embodiment of the present invention, the number of the plurality of second dimples is 60 or more. Thereby, it is found that the lift coefficient is increased in all the speed ranges, and the extreme decrease in the lift coefficient in the low speed range can be suppressed.

In the golf ball according to the embodiment of the present invention, the ratio of the depth to the diameter of each of the plurality of second dimples is 0.050 or more and 0.240 or less.

In the golf ball according to the embodiment of the present invention, the number of the plurality of second dimples is 60 or more and 2,160 or less.

[Examples]

Hereinafter, an embodiment of the present invention will be described. In addition, the same or equivalent components as those described above are denoted by the same reference numerals, and the description is not repeated unless otherwise specified.

【Table 2】

Referring to Tables 1 and 2, Examples 1 to 8 are examples of the present invention, and Comparative Examples 1 to 3 are comparative examples with respect to the present invention. Examples 1 to 8 and Comparative Examples 1 to 3 have the configurations shown in Table 1.

Referring to FIG. 4, the golf ball of Comparative Example 1 has no second dimple. Further, the golf ball of the first embodiment has the same configuration as that of the configuration shown in Fig. 1. The golf balls of Examples 2 and 3 were shallower in depth than the first embodiment.

Referring to Fig. 5, the golf ball of the fourth embodiment is compared with the first embodiment, and the number of the second dimples 2 is large. Therefore, in the golf ball of the fourth embodiment, the arrangement of the second dimples 2 is different from that of the first embodiment.

Further, in the golf ball of Comparative Example 2, the diameter of the second dimple 2 was smaller as compared with Examples 1 to 8. On the other hand, in the golf ball of Comparative Example 3, the diameter of the second dimple 2 was larger than that of Examples 1 to 8.

Further, the golf ball of the fifth embodiment has a smaller diameter of the second dimple 2 and a deeper depth of the second dimple than the other embodiments. Then, the ratio of the depth to the diameter of the second dimple is larger. Also, the ratio of the diameter of the second dimple (the diameter of the SS dimple) to the maximum diameter of the plurality of first dimples (the diameter of the LL dimple) (SS diameter / LL diameter) is changed as compared with other embodiments. small.

Compared with the first embodiment, the golf ball of the sixth embodiment has a smaller number of the second dimples 2 and is one-half the number of the first embodiment.

The golf ball of Embodiment 7 has a larger diameter of the second dimple 2 than the other embodiments. Then, next to Embodiment 3, the ratio of the depth to the diameter of the second dimple 2 becomes smaller. Also, compared to other embodiments, the diameter of the second dimple (the diameter of the SS dimple) is the maximum diameter of the plurality of first dimples (the straightness of the LL dimple) The ratio of the diameter (SS diameter / LL diameter) is large.

In the golf ball of the eighth embodiment, the number of the second dimples 2 is smaller than that of the first and sixth embodiments, and is one third of the number of the first embodiment.

As shown in Table 1, the diameter of the second dimple (SS dimple) (1.04 mm or more, 1.87 mm or less) has a ratio of the maximum diameter (diameter of the LL dimple) of 4.70 mm of the plurality of first dimples to 0.22 mm or more. , 0.40 or less. Further, the diameter of the second dimple (SS dimple) is 1.04 mm or more and 1.87 mm or less. If the diameter of the second dimple (SS dimple) is 1.0 mm or more and 1.9 mm or less, the same effect as in the present embodiment is achieved.

Next, the relationship between the speed of the balls, the lift coefficient CL, and the spin parameter Sp of Examples 1 to 8 and Comparative Examples 1 to 3 will be described. Further, the spin parameter Sp is defined by the following formula (1). The spin parameter is expressed as the peripheral speed/speed.

Sp=πdN/U (1)

The symbol of the formula (1) will be described. d is the diameter (m), N is the rotational speed (rps), and U is the velocity of the ball (m/s). For example, when the speed of the ball (ball speed) is 60 m/s and the rotation speed is 2700 rpm, the spin parameter Sp ≒ 0.1.

The lift coefficient CL is an air force measuring device disclosed in Japanese Patent No. 4982148, which blows a golf ball that rotates in the wind direction, and calculates three components (resistance, lift, side force) of the generated aerodynamic force. The spin parameters can be changed in a timely manner by adjusting the flow rate of the blowing wind and the number of revolutions of the golf ball. Further, the measurement of the lift coefficient can be performed by using a method of measuring the orbit by infrared rays and calculating the track based on the track, a golf ballistic measuring instrument represented by TrackMan manufactured by TrackMan, and the like.

The initial speed of the golf ball when flying out, the average value of the average man is At about 60 m/s, the average value of a male professional golfer is about 70 m/s. On the other hand, such as "Mingwei Zhangsi, Gou Tianwu, Xiayuan Renzhi, "Aerodynamic Measurement and Flight Experiment of Golf Balls Rotating at High Speed in the Same Airflow", 2004, Proceedings of the Japan Society of Mechanical Engineers, Series B, Volume 70, No. 698, pp. 2371-2377", in the flow rate of 35~80m/s, there is no Reynolds number in the lift coefficient and the drag coefficient, that is, the speed dependence. The initial velocity of the golf ball when flying out depends only on the spin parameter. The experiment conducted in this embodiment is at most 44 m/s, but if a predetermined number of revolutions is obtained, the aerodynamic characteristics in the flow rate range to a flow rate of 80 m/s can be grasped.

Referring to FIGS. 6 to 8, in the golf balls of Comparative Examples 1 and 2, the fluctuation of the ball speed lift coefficient CL is large. Specifically, the fluctuation of the lift coefficient CL is large at a ball speed of 30 m/s or less. Further, in Comparative Example 3, the fluctuation of the lift coefficient CL is not large, but the overall lift coefficient CL is small.

Referring to FIGS. 9 to 16, in Examples 1 to 8, the fluctuation of the lift coefficient CL by the ball speed was small as compared with Comparative Examples 1 and 2. In particular, in the first, second, and fourth embodiments, the fluctuation of the lift coefficient CL by the ball speed becomes extremely small.

Next, the relationship between the lift coefficient CL and the depth/diameter of the second dimple will be described.

Referring to Fig. 17, in the case where the spin parameter Sp is 0.1 and the speed U of the ball is 44 m/s and 28 m/s, the speeds U of the balls are 44 m/s in comparison with the comparative example 1 in the examples 1 to 4. The lift coefficient CL is equal, and the lift coefficient CL is larger at 28 m/s. In particular, in the first, second, and fourth embodiments, the lift coefficient CL can be increased in the low speed range in which the speed U of the ball is 28 m/s.

In addition, referring to Fig. 18, the difference in lift coefficient CL at 44 m/s and 28 m/s shown in Fig. 17 is discussed, and it is shown that Examples 1 to 4 are compared with Comparative Example 1. The difference in lift coefficient CL is small. That is, in the first to fourth embodiments, as compared with the comparative example 1, it was shown that the extreme reduction of the lift coefficient CL can be suppressed in the low speed range in which the velocity U of the ball is 28 m/s. Further, in Examples 1, 2, and 4 in which the ratio of the depth to the diameter of the second dimple is large, compared with Comparative Example 1, it is shown that the speed U of the ball is 28 m/s in the low speed region. The ground is suppressed from the extreme reduction of the lift coefficient CL. Therefore, in the respective depth-to-diameter ratios of the plurality of second dimples 2 of the embodiments 1 to 4, it is shown that the extreme of the lift coefficient CL can be largely suppressed in the low velocity region where the velocity U of the ball is 28 m/s. The reduction.

Next, the relationship between the lift coefficient CL and the ratio of the respective diameters of the second dimples to the maximum diameters of the plurality of first dimples (the ratio of the diameters) will be described.

Referring to FIG. 19, in the case where the spin parameter Sp is 0.1 and the speed U of the ball is 44 m/s and 28 m/s, the speeds of the balls are compared in the comparison of the examples 1, 5, and 7 with the comparative examples 1 and 2. The lift coefficient CL is equal to 44 m/s, and the lift coefficient CL is larger at 28 m/s.

In addition, referring to Fig. 20, the difference in lift coefficient CL at 44 m/s and 28 m/s shown in Fig. 19 is discussed, and the lift coefficients CL are shown in comparison with Examples 1, 5, and 7 and Comparative Examples 1 and 2. The difference is small. That is, in Examples 1, 5, and 7, compared with Comparative Examples 1 and 2, it was shown that the extreme reduction of the lift coefficient CL can be suppressed even in the low speed range in which the velocity U of the ball is 28 m/s. Therefore, in the ratio of the diameters of the first, fifth, and seventh embodiments, it is shown that the extreme decrease in the lift coefficient CL can be suppressed even in the low speed range in which the velocity U of the ball is 28 m/s.

Referring to FIG. 21, in the case where the spin parameter Sp is 0.1 and the velocity U of the ball is 44 m/s, the examples 1 to 8 and the comparative examples 1 and 2 are compared with the comparative example 3. The value of the lift coefficient CL is large at a speed U of 44 m/s. That is, Comparative Example 3 is compared with Examples 1 to 8 and Comparative Examples 1 and 2, and shows that the value of the lift coefficient CL is small in the case where the velocity U of the ball is 44 m/s. Therefore, in the first to eighth embodiments, it is shown that the value of the lift coefficient CL does not decrease in the case where the speed U of the ball is 44 m/s. Further, in the diameter of the second dimple shown in Comparative Example 3, the value of the lift coefficient CL was lowered in the case where the velocity U of the ball was 44 m/s.

Next, the relationship between the lift coefficient CL and the number of the second dimples will be described.

Referring to FIG. 22, in the case where the spin parameter Sp is 0.1 and the speed U of the ball is 44 m/s and 28 m/s, Examples 1, 4, 6, 7, and 8 are compared with Comparative Example 1, in the ball. The lift coefficient CL is equal to the speed U of 44 m/s, and the lift coefficient CL is larger at 28 m/s.

In addition, referring to Fig. 23, the difference in lift coefficient CL at 44 m/s and 28 m/s shown in Fig. 22 is discussed, and the lift coefficients of Examples 1, 4, 6, 7, and 8 are compared with Comparative Example 1. The difference in CL is small. That is, in Examples 1, 4, 6, 7, and 8, compared with Comparative Example 1, it was shown that the extreme reduction of the lift coefficient CL can be suppressed even in the low speed range in which the velocity U of the ball is 28 m/s. Therefore, in the number of the second dimples of the first, fourth, sixth, seventh, and eighth embodiments, it is shown that the extreme decrease in the lift coefficient CL can be suppressed even in the low speed range in which the velocity U of the ball is 28 m/s.

By the above, as in the embodiments 1 to 8, the ratio of the depth to the diameter of each of the plurality of second dimples 2 is 0.050 or more, and the respective diameters of the plurality of second dimples are the largest for the plurality of first dimples. The ratio of the diameters is 0.21 or more and 0.41 or less, and it is found that the lift coefficient is increased in all the speed ranges, and the extreme decrease in the lift coefficient in the low speed range can be suppressed. In addition, by a plurality of second dimples Each of the diameters is 1.0 mm or more and 1.9 mm or less, and it is found that the lift coefficient is increased in all the speed ranges, and the extreme decrease in the lift coefficient in the low speed range can be suppressed.

Next, the flight distances of Comparative Examples 1 to 3 and Examples 1 to 8 were measured by simulation.

Referring to Table 2, the flight distance is compared with the condition 1 corresponding to the hitting condition of the male professional player, the condition 2 corresponding to the hitting condition of the female professional player, and the condition 3 corresponding to the hitting condition of the general amateur player. Condition 1 was set to an initial velocity of 78 m/s, a knock-out angle of 12 degrees, and a spin amount of 2,200 rpm. Condition 2 was set to an initial velocity of 65 m/s, a knockout angle of 15 degrees, and a spin amount of 2,500 rpm. Condition 3 was set to an initial velocity of 60 m/s, an ejection angle of 12 degrees, and a spin amount of 2,800 rpm. However, the spin axis is a pure vertical rotation that is set to be untilted.

The flight distance is the distance from the striking position to the horizontal drop again after the submarine conditions are substituted and the air temperature is 24° C., the humidity is 50%, the atmospheric pressure, and the air is not flying. In addition, the golf ball used is 45.6g in mass, 4.28mm in diameter, and has a moment of inertia of 8.1×10 ^-6 kg. m ² , the dimples have the shapes of Comparative Examples 1 to 3 and Examples 1 to 8.

The air characteristics used in calculating the flight distance are the lift coefficient characteristics shown in Figures 6-16. In addition, the drag coefficient characteristic is a characteristic that uses common. The position after flying out is calculated using the method described in paragraphs 0032 to 0092 of Japanese Patent No. 3825359.

In any of the conditions 1 to 3, the flying distances of the examples 1 to 8 were larger than those of the comparative examples 1 to 3. Thereby, it can be confirmed that the embodiments 1 to 8 can improve the flight distance performance.

The embodiments and examples disclosed herein are illustrative in all respects and should not be construed as limiting. The scope of the present invention is defined by the scope of the claims, and the scope of the claims is intended to be

[Industrial availability]

The invention may be particularly advantageous for use in golf balls having dimples formed on the surface.

1‧‧‧First dimple

2‧‧‧second dimple

3‧‧‧flat

11‧‧‧LL recess

12‧‧‧L dimple

13‧‧‧LS dimple

14‧‧‧M dimple

15‧‧‧S dimple

Claims (5)

A golf ball comprising: a plurality of first dimples formed on a surface; and a plurality of second dimples formed around the plurality of first dimples in the surface and having a plurality of first dimples smaller than the plurality of first dimples a diameter; wherein a ratio of depth to diameter of each of the plurality of second dimples is 0.050 or more; and a ratio of a diameter of each of the plurality of second dimples to a maximum diameter of the plurality of first dimples is 0.21 Above, below 0.41. A golf ball comprising: a plurality of first dimples formed on a surface; and a plurality of second dimples formed around the plurality of first dimples in the surface and having a plurality of first dimples smaller than the plurality of first dimples The diameter of each of the plurality of second dimples is 0.0550 or more in diameter; and each of the plurality of second dimples has a diameter of 1.0 mm or more and 1.9 mm or less. The golf ball according to claim 1 or 2, wherein the number of the plurality of second dimples is 60 or more. The golf ball according to claim 1 or 2, wherein the ratio of the depth to the diameter of each of the plurality of second dimples is 0.050 or more and 0.240 or less. The golf ball according to claim 1 or 2, wherein the number of the plurality of second dimples is 60 or more and 2160 or less.