golf ball

Abstract

The aim is to provide a golf ball with a novel surface that can increase flight distance by improving aerodynamic performance through dimples compared to conventional balls. [Solution] The present invention provides a golf ball comprising a plurality of dimples and a land area surrounded by the plurality of dimples, wherein the land area is composed of a plurality of land area pieces, one land area piece having a shape having at least three vertices, and including a land area piece of a specific shape in which the land area piece is substantially point-contacting and connected to another adjacent land area piece at the vertices, and the outer edge of the land area piece of the specific shape is composed of a plurality of edge elements, and the proportion of the number of land area pieces of a unique shape in which all of the edge elements are formed by a predetermined curve is adjusted to a predetermined range of the total number of land area pieces constituting the land area.

Description

Technical Field

[0001] The present invention relates to a golf ball having a land portion and a large number of dimples formed on the ball surface.

Background Art

[0002] In a golf ball, in order for the hit ball to obtain a large flight distance, it is well known that high resilience inherent in the ball itself and reduction of air resistance during flight by dimples arranged on the ball surface are important. For the purpose of reducing air resistance, various methods have been proposed to arrange dimples on the ball surface as densely and evenly as possible.

[0003] Normally, the design of dimples on a golf ball takes a method of arranging dimples of one or a plurality of predetermined shapes on the ball surface. However, in the method of arranging dimples of such a predetermined shape, when the surface occupancy rate of the dimples becomes very high, since the surface of the golf ball is spherical, it becomes difficult to arrange the dimples evenly, and there are portions where the gaps between the dimples become wide or narrow, and the gaps between the dimples often become non-uniform. If the gaps between the dimples are non-uniform, there is a possibility that the aerodynamic performance of the golf ball is extremely poor even if the surface occupancy rate of the dimples is high.

[0004] For example, Patent Document 1 (Japanese Patent Application Laid-Open No. 2004-105200) describes forming ridge-shaped protrusions on the surface of a golf ball, which is completely different from the conventional concept of forming a large number of dimples on the surface of a golf ball. By forming ridge-shaped protrusions in this way, it is described that the occupancy rate of the portion without protrusions, which corresponds to the surface occupancy rate of conventional dimples, can be easily increased, and the aerodynamic performance can be improved.

[0005] Furthermore, Patent Document 2 (Japanese Patent Publication No. 2011-031043) proposes a golf ball comprising a plurality of dimples and a land area surrounded by the plurality of dimples, wherein the land area has a shape having at least one vertex, the land area substantially touches at points with at least two or more adjacent land areas, and the area of ​​the land area is within a predetermined range. In other words, by making the shape of the land area a specific shape, the above golf ball can maintain a uniform gap between dimples even if the surface coverage of the dimples is high, thereby improving aerodynamic performance and increasing flight distance.

[0006] However, there is a need for a golf ball with a novel surface shape combining land area and dimples that can further improve aerodynamic performance through dimples compared to the golf ball proposed above, and potentially increase flight distance. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2004-105200 [Patent Document 2] Japanese Patent Publication No. 2011-031043 [Overview of the project] [Problems that the invention aims to solve]

[0008] This invention has been made in view of the above circumstances, and aims to provide a golf ball with a novel surface that can increase flight distance by improving aerodynamic performance through dimples compared to conventional balls. [Means for solving the problem]

[0009] The inventors of this invention conducted diligent studies to achieve the above objectives. As a result, instead of focusing on the dimples themselves, they focused on the shape of the land portion on the outer surface of the ball to increase the surface coverage of the dimples, and by optimizing this shape, they completed the present invention. Specifically, they created a land portion with a specific shape, having at least three vertices in the shape of the land portion piece, which is the smallest unit of the land portion on the outer surface of the ball, and at these vertices, it is substantially connected to other adjacent land portions by point contact. Furthermore, they found that the above problems of the present invention can be solved by adjusting the shape of the outer edge of the land portion pieces so that the proportion of land portions with a unique shape, in which all of the edge elements forming the outer edge of this land portion are formed with curves of 0.40 or 0.35 or less, is 30% or more or 20% or more of the total number of land portions constituting the land portion, in order to finish the edge elements with low curvature curves. This led to the creation of the present invention.

[0010] Therefore, the present invention provides the following golf ball. 1. A golf ball comprising a plurality of dimples and a land area surrounded by the plurality of dimples, wherein the land area is composed of a plurality of land area pieces, each land area piece having a shape with at least three vertices, and including a land area piece of a specific shape in which the land area piece is substantially connected to another adjacent land area piece by a point at the vertices, and the outer edge of the land area piece of the specific shape is composed of a plurality of edge elements, and the proportion of land area pieces of a unique shape in which all of the edge elements are formed by a curve with a curvature of 0.40 or less is 30% or more of the total number of land area pieces constituting the land area. 2. The golf ball as described in item 1 above, wherein the proportion of land segments with a unique shape in which all of the above edge elements are formed by curves with a curvature of 0.40 or less is 50% or more of the total number of land segments constituting the land. 3. A golf ball comprising a plurality of dimples and a land area surrounded by the plurality of dimples, wherein the land area is composed of a plurality of land area pieces, each land area piece having a shape with at least three vertices, and including a land area piece of a specific shape in which the land area piece is substantially connected to another adjacent land area piece by a point at the vertices, and the outer edge of the land area piece of the specific shape is composed of a plurality of edge elements, and the proportion of land area pieces of a unique shape in which all of the edge elements are formed by a curve with a curvature of 0.35 or less is 20% or more of the total number of land area pieces constituting the land area. 4. The golf ball as described in item 3 above, wherein the proportion of land segments with a unique shape in which all of the above edge elements are formed by curves with a curvature of 0.35 or less is 30% or more of the total number of land segments constituting the land. 5. The periphery of the land portion having the above-mentioned unique shape is composed of six curved edge elements, as described in 1 or 3 above. 6. The golf ball according to 1 or 3 above, wherein the land portion is formed by connecting 4,000 or more curved edge elements. 7. The golf ball according to item 1 or 3 above, wherein the proportion of edge elements with a curvature of 0.40 or less among the curved edge elements forming the above land portion is 70% or more. 8. A golf ball as described in 1 or 3 above, having eight or more circular dimples. 9. A golf ball as described in item 1 or 3 above, wherein the proportion of circular dimples to the total number of dimples is 10% or less. 10. The total volume of dimples beneath the plane surrounded by the outer edge of the dimples is 300-600 mm². 3 The golf ball described in item 1 or 3 above, which is one of the following: 11. The golf ball described in 1 or 3 above, wherein the land portion consists of three or more pieces of different sizes or shapes. 12. A golf ball as described in item 1 or 3 above, having 200 to 500 dimples. 13. A golf ball as described in 1 or 3 above, wherein the dimple area coverage ratio is 60-95%. [Effects of the Invention]

[0011] The golf ball of the present invention can improve the aerodynamic performance by dimples and increase the flight distance more than conventional ones, and exhibits a novel ball appearance.

Brief Description of the Drawings

[0012] [Figure 1] It is a schematic view showing the golf balls of Examples 1 to 3 which are embodiments of the present invention. [Figure 2] FIG. 2(A) shows a partially enlarged view showing the ball surface of FIG. 1, and (B) is a schematic view showing only the land portion in FIG. 2(A). [Figure 3] It is a schematic view showing the golf ball of Comparative Example 2. [Figure 4] FIG. 4(A) shows a partially enlarged view showing the ball surface of FIGS. 3 and 5, and (B) is a schematic view showing only the land portion in FIG. 4(A). [Figure 5] It is a schematic view showing the golf ball of Comparative Example 3. [Figure 6] It is a schematic view showing the golf ball of Comparative Example 1. [Figure 7] It is a partially enlarged view showing the ball surface of FIG. 6. [Figure 8] FIG. 8(A) is a schematic perspective view of the injection mold (lower mold) of Example 1, and (B) is a schematic plan view of the mold seen from above. [Figure 9] FIG. 9(A) is a schematic enlarged view of the vicinity of the parting line of the mold of FIG. 8, and (B) is a schematic view showing the shape of the opening of the gate portion.

Mode for Carrying Out the Invention

[0013] Hereinafter, the present invention will be described in more detail. The golf ball of the present invention comprises a plurality of dimples and a land area surrounded by the plurality of dimples. This land area refers to the portion of the ball surface in which no dimples are formed. The boundary line between the land area and the dimples corresponds to the outer edge of the land area or the outer edge of the dimples, and in the present invention, this is referred to as the edge or edge element.

[0014] The above-mentioned land portion is composed of numerous land portion pieces. For example, Figure 1 shows a plan view of a golf ball according to Embodiments 1 to 3 of the present invention, which has numerous dimples D and a land portion L. Figure 2(A) is an enlarged view of region T, and shows that numerous land portion pieces 10, which are the smallest units of the land portion L, are formed therein. That is, six land portion pieces 10 are formed around one dimple D. As a result, the outer edge of the dimple D has a shape that is approximately dodecagonal. The sides between the vertices of this approximately dodecagon are not straight but curved.

[0015] Furthermore, as shown in Figures 2(A) and (B), the land segment 10 has a tridentate shape (a shape with three radial extensions spaced approximately 120 degrees apart), and each radially extending portion gradually narrows outward, with a pointed tip. This pointed portion is the vertex 1a, meaning that one land segment 10 has three vertices 10b, and at these vertices, it substantially touches another adjacent land segment at a single point. In addition, the outer edge of one land segment 10 consists of six edge elements 10a. In other words, the land segment takes on the tridentate shape described above by the connection of these six edge elements.

[0016] Furthermore, in this invention, the shape of the land segment is not limited to the three-pronged shape described above. For example, any shape having at least three vertices, such as a Y-shape, T-shape, or star shape, and where adjacent land segments are substantially connected at points at these vertices, is acceptable. In addition, the land segment is not limited to just one type, but two or more types with different sizes or shapes can be used.

[0017] In the present invention, it is preferable that the edge elements of the land portion are formed with a curve of curvature of 0.40 or less. In the present invention, by using a curve with a curvature of 0.40 or less as the edge element, the novelty of the ball surface (appearance) and the optimal shape for aerodynamic performance are configured, thereby increasing the flight distance. The curvature of the edge element is preferably 0.40 or less, more preferably 0.35 or less, and even more preferably 0.30 or less. In this way, the curvature of each edge element is set to be as small as described above in order to avoid as much as possible shapes that create air resistance on the inner circumferential side surface (edge) of the dimple.

[0018] The proportion of land segments in which all of the above edge elements are formed with a curve of curvature 0.40 or less is preferably 30% or more, more preferably 40% or more, and even more preferably 50% or more, of the total number of land segments constituting the land.

[0019] Furthermore, the proportion of land segments in which all of the above-mentioned edge elements are formed with a curve of 0.35 or less is preferably 20% or more, and more preferably 30% or more, of the total number of land segments constituting the land.

[0020] Furthermore, in this invention, it is preferable that the total number of curves forming the edge elements is 4000 or more. And, among the curved edge elements forming the land portion, the proportion of edge elements with a curvature of 0.40 or less is preferably 70% or more, and more preferably 75% or more. By increasing the proportion of curves with a predetermined curvature or less in this way, air resistance on the ball surface can be reduced, thereby further increasing the flight distance.

[0021] The area of ​​the land portion 10 is 0.05 mm². 2 Preferably, it should be 0.5 mm or more, and more preferably 0.5 mm 2 More preferably 0.62 mm 2 The above is the limit, and the upper limit is 16.0 mm. 2 The following is preferable, and more preferably 8.5 mm 2 More preferably 1.65 mm2 The following applies:

[0022] The length of the outer circumference of the land portion 10 is preferably 1.6 mm or more, more preferably 4.0 mm or more, and the upper limit is preferably 19.4 mm or less, more preferably 9.9 mm or less.

[0023] The outer circumference length of dimple D is preferably 3.2 mm or more, more preferably 6.3 mm or more, and the upper limit is preferably 38.8 mm or less, more preferably 19.8 mm or less. By setting the outer circumference length of the dimple within the above range, the aerodynamic performance can be improved by designing the land portion in the manner described above.

[0024] The surface of the land area L forms the spherical surface of a golf ball, and the surface of the dimple D is indented from a hypothetical sphere assuming there are no dimples on the surface of the golf ball, and has a smooth curved shape from the boundary with the land area L toward the center of the dimple, where the dimple is deepest.

[0025] The present invention is not particularly limited in terms of the depth of the dimple D, but the depth at the center, which is the deepest position, is preferably 0.05 mm or more, more preferably 0.10 mm or more, and the upper limit is preferably 0.45 mm or less, more preferably 0.35 mm or less.

[0026] In this way, by arranging land pieces having a predetermined shape on a golf ball to design dimples on the ball's surface, and by arranging multiple land pieces so that adjacent land pieces touch at virtually points, it is possible to increase the proportion of the dimple surface area on the virtual spherical surface of the golf ball, i.e., the surface coverage ratio of the dimples, while maintaining uniform gaps between the dimples. Consequently, the aerodynamic performance of the golf ball is significantly improved, resulting in longer flight distances. Furthermore, the surface coverage ratio of the dimples can be easily controlled by changing the shape of the land pieces.

[0027] The surface coverage of the dimples is preferably 60% or more, and more preferably 70% or more. By setting the surface coverage of the dimples to 60% or more, air resistance can be reduced. On the other hand, the surface coverage of the dimples is preferably 95% or less. Specifically, the surface coverage of the dimples refers to the ratio (SR value) of the total dimple area, defined by the plane edges surrounded by the edges of the dimples, to the ball surface area assuming that no dimples exist.

[0028] The total number of land segments formed on the surface of the golf ball is preferably 434 or more, and more preferably 540 or more. On the other hand, the total number of land segments 12 is preferably 864 or less, and more preferably 756 or less. By setting the total number of land segments within this range, the surface coverage ratio of the dimples on the ball surface can be designed to fall within the above preferred range.

[0029] The total number of dimples formed on the surface of a ball is usually between 200 and 500, but this is determined by the total number of land segments and the relationship between the land segments and the dimples. For example, if the total number of land segments is 434, and 6 land segments form one dimple, the total number of dimples will be 218. Similarly, if 6 land segments form one dimple, then with a total of 540 land segments, the total number of dimples will be 272; with a total of 756 land segments, the total number of dimples will be 380; and with a total of 864 land segments, the total number of dimples will be 434.

[0030] Regarding the shape of the dimples, typically, due to the arrangement of the land fragments described above, the majority will be non-circular dimples, but circular dimples can also be formed. When circular dimples are present, it is preferable that there be 8 or more circular dimples, and more preferably 10 or more. Furthermore, it is preferable that the proportion of circular dimples to the total number of dimples be 10% or less, and more preferably 5% or less. Thus, the dimples formed on the surface of the golf ball according to the present invention are not limited to non-circular dimples, but can also include circular dimples.

[0031] Furthermore, the total volume of the dimples refers to the sum of the volumes of each dimple formed in a single ball, below the plane surrounded by the edges of the dimples. While there are no particular limitations on this total dimple volume, it is preferably 300-600 mm². 3 It is preferable that this be the case. By adjusting within the above range, the ball trajectory after hitting with the driver (W#1) can be optimized and stabilized to achieve the desired distance.

[0032] The internal structure of a golf ball can be that of a one-piece ball, or a multi-piece golf ball such as a two-piece or three-piece golf ball. In particular, the dimples of the present invention can be used more effectively on low-spin multi-piece golf balls. When a ball is struck with a golf club designed for long distances, such as a driver (W#1) or a long iron, an appropriate balance between the lift and drag of the ball is necessary to increase the distance, improve wind resistance, and achieve a longer roll. This balance between the lift and drag of the ball depends on the structure of the ball, the rubber and resin materials used, and especially on the shape, area, and total number of land pieces used, as well as the surface coverage of the dimples.

[0033] The golf ball of the present invention can be manufactured using a mold. For the creation of such a mold, a method can be used in which 3D CAD or CAM is used to directly carve the entire surface shape in three dimensions from a reversal master mold, or a method can be used to directly carve the cavity portion of the molding die in three dimensions. By designing the mold so that the parting line passes through the land portion of the golf ball surface, finishing (trimming) can be facilitated. Furthermore, to evenly distribute the land portion pieces across the spherical surface of the golf ball, it is preferable to utilize arrangement methods such as polyhedra (icosahedron, dodecahedron, octahedron, etc.) or 3-fold or 5-fold symmetry. [Examples]

[0034] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0035] [Examples 1-3, Comparative Examples 1-3] After preparing the core composition using a rubber compound mainly composed of polybutadiene as shown in Table 1 below, a core with a diameter of 37.6 mm was produced by vulcanization at 155°C for 20 minutes.

[0036] [Table 1]

[0037] Details regarding the core formulation mentioned above are as follows: • Polybutadiene rubber: Product name "BR730" (manufactured by ENEOS Material Co., Ltd.) • Zinc acrylate: Product name "ZN-DA85S" (manufactured by Nippon Shokubai Co., Ltd.) • Zinc stearate: Product name "Zinc Stearate GP" (manufactured by NOF Corporation) • Organic peroxide: Dicumyl peroxide, trade name "Perkmyl D" (manufactured by NOF Corporation) • Anti-aging agent: Product name "Nocrack MB" (manufactured by Ouchi Shinko Chemical Industry Co., Ltd.) • Zinc oxide: Product name "Zinc Oxide 3 Types" (manufactured by Sakai Chemical Co., Ltd.) • Pentachlorothiophenol zinc salt: Manufactured by ZHEJIANG SHOU&FU CHEM Co., Ltd.

[0038] Next, using an injection molding die, an intermediate layer with a thickness of 1.30 mm and a Shore D hardness of "50" was formed around the core surface by injection molding with the intermediate layer resin material shown in Table 2. Then, using an injection molding die having numerous dimple-forming protrusions within the cavity, a cover (outermost layer) with a thickness of 1.25 mm and a Shore D hardness of "62" was formed around the intermediate layer-covered sphere by injection molding with the cover (outermost layer) resin material shown in Table 2.

[0039] [Table 2]

[0040] The details of the ingredients listed in the table above are as follows: • "HPF1000" manufactured by THE DOW CHEMICAL COMPANY • "AM7318" Ionomer resin manufactured by Mitsui Dow Polychemicals. • "AM7327" Ionomer resin manufactured by Mitsui Dow Polychemicals. • Titanium dioxide manufactured by Sakai Chemical Industry Co., Ltd.

[0041] Dimples and land areas in each example As described above, dimples and land fragments of a predetermined shape were formed on the surface of the cover by injecting the resin material of the cover using an injection molding die having numerous protrusions for dimple formation within the cavity. Details are shown in Table 1. In Table 1, a photograph of dimple No. 1 is shown in Figure 1, a photograph of No. 2 is shown in Figure 3, a photograph of No. 3 is shown in Figure 5, and a photograph of No. 4 is shown in Figure 6.

[0042] The measurement conditions and methods for the radius of curvature of the edge elements of the land portion formed on the ball surface in each example are as follows. The curvature of each curve was calculated by analyzing six or more curves (edge ​​elements) that make up the shape of the land portion of the ball surface. Each curve constituting the shape of the land portion was divided into sections by 20 equal plots, and the curvature of the curve was calculated for each section, determining the maximum and minimum curvature per curve. For circular dimples, the land portion (land portion) sandwiched between each dimple was individually specified, and the maximum and minimum curvature of the arc of each dimple was calculated. This curvature was calculated using either a method of analyzing each curve on the drawing using a computer, or a method of using the equation of the curves constituting the land portion based on the measured dimple shape. The number of curves with a maximum curvature of 0.4 or less was counted, and the ratio to the total number of curves constituting the land portion was calculated.

[0043] Figure 8 shows the injection molding die used in Example 1. Figure 8(A) is a schematic perspective view of the injection molding die (lower die) of Example 1, and Figure 8(B) is a schematic plan view of the die as seen from above. As shown in these figures, the die 30 has a hemispherical cavity 31 having corresponding dimple-forming protrusions 31a, 31b with a large number of non-circular dimples and a small number of circular dimples, and the parting line (dividing surface) PL of the die is not straight but has an uneven or wave-like shape. In addition, six gate portions 32 are provided along the parting line of the die to allow the resin material of the cover to flow into the cavity.

[0044] Furthermore, Figure 9(A) is an enlarged view of the area near the perdin line of the above-mentioned mold, and a gate portion 32 is formed in the area enclosed by the circular dotted line. The shape of the opening of this gate portion 32 is an elongated, non-circular shape, as shown in Figure 9(B).

[0045] The flight of the golf ball (W#1) in each example was evaluated using the method described below. The results are shown in Table 1.

[0046] Flight evaluation (W#1, HS50m / s) A golf hitting robot will be fitted with a driver club and hit the ball at a head speed (HS) of 50 m / s. The spin rate and total distance will be measured. The club used will be a Bridgestone Sports "TourB XD-5 Driver (2017 model)" (loft angle 9.5°), and will be evaluated according to the following criteria. 〔Judgment criteria〕 ◎ ··· The total compared to Comparative Example 1 is +3.2m or more. ○ ··· The total compared to Comparative Example 1 is +2.0m or more and less than +3.2m. △ ··· The total compared to Comparative Example 1 is +0.8m or more and less than +2.0m. × ··· The total compared to Comparative Example 1 is less than +0.8m.

[0047] Flight evaluation (W#1, HS45m / s) A golf hitting robot equipped with a driver club will be used to measure spin rate and total distance when hitting the ball at a head speed (HS) of 45 m / s. The club used will be the same as described above. 〔Judgment criteria〕 ◎ ··· The total compared to Comparative Example 1 is +3.2m or more. ○ ··· The total compared to Comparative Example 1 is +2.0m or more and less than +3.2m. △ ··· The total compared to Comparative Example 1 is +0.8m or more and less than +2.0m. × ··· The total compared to Comparative Example 1 is less than +0.8m.

[0048] Flight evaluation (W#1, HS40m / s) A golf hitting robot equipped with a driver club will be used to measure spin rate and total distance when hitting the ball at a head speed (HS) of 45 m / s. The club used will be the same as described above. 〔Judgment criteria〕 ◎ ··· The total compared to Comparative Example 1 is +3.2m or more. ○ ··· The total compared to Comparative Example 1 is +2.0m or more and less than +3.2m. △ ··· The total compared to Comparative Example 1 is +0.8m or more and less than +2.0m. × ··· The total compared to Comparative Example 1 is less than +0.8m.

[0049] [Table 3]

[0050] As shown in the results in Table 1, the golf balls of Comparative Examples 1 to 3 are inferior to the present invention (example) in the following respects. Comparative Example 1 is a golf ball consisting only of conventional circular dimples, and its flight distance is significantly inferior to that of each embodiment under all conditions. Comparative Example 2, although the ball surface contains a unique three-pronged land portion within the land portion, has a very small proportion of these land portions where all edge elements are formed with a curve of curvature 0.40 or less. As a result, the flight distance under all conditions is significantly inferior to that of each embodiment. Comparative Example 3, although the ball surface contains a unique three-pronged land portion within the land portion, has a small proportion of these land portions where all of the edge elements are formed with a curve of 0.40 or less or 0.35 or less. As a result, the flight distance under HS50m / s and HS45m / s conditions is significantly inferior to that of the respective embodiments. [Explanation of symbols]

[0051] 1 golf ball L Land D-dimple 10 land piece 10a Edge element 10b Vertex of the continental portion

Claims

1. A golf ball comprising a plurality of dimples and a land area surrounded by the plurality of dimples, wherein the land area is composed of a plurality of land area pieces, each land area piece having a shape with at least three vertices, and including a land area piece of a specific shape in which the land area piece is substantially connected to another adjacent land area piece by a point at the vertices, and the outer edge of the land area piece of the specific shape is composed of a plurality of edge elements, and the proportion of land area pieces of a unique shape in which all of the edge elements are formed by a curve with a curvature of 0.40 or less is 30% or more of the total number of land area pieces constituting the land area.

2. The golf ball according to claim 1, wherein the proportion of the number of land segments with a unique shape in which all of the above edge elements are formed by curves with a curvature of 0.40 or less is 50% or more of the total number of land segments constituting the land.

3. A golf ball comprising a plurality of dimples and a land area surrounded by the plurality of dimples, wherein the land area is composed of a plurality of land area pieces, each land area piece having a shape with at least three vertices, and including a land area piece of a specific shape in which the land area piece is substantially point-contacting and connected to another adjacent land area piece at the vertices, and the outer edge of the land area piece of the specific shape is composed of a plurality of edge elements, and the proportion of land area pieces of a unique shape in which all of the edge elements are formed by a curve with a curvature of 0.35 or less is 20% or more of the total number of land area pieces constituting the land area.

4. The golf ball according to claim 3, wherein the proportion of the number of land segments with a unique shape in which all of the above edge elements are formed with a curve of curvature of 0.35 or less is 30% or more of the total number of land segments constituting the land.

5. The golf ball according to claim 1 or 3, wherein the peripheral edge of the uniquely shaped land portion is composed of six curved edge elements.

6. The golf ball according to claim 1 or 3, wherein the above land portion is formed by connecting 4,000 or more curved edge elements.

7. The golf ball according to claim 1 or 3, wherein, among the curved edge elements forming the above-mentioned land portion, the proportion of edge elements with a curvature of 0.40 or less is 70% or more.

8. A golf ball according to claim 1 or 3, having eight or more circular dimples.

9. The golf ball according to claim 1 or 3, wherein the proportion of circular dimples to the total number of dimples is 10% or less.

10. The total volume of dimples beneath the plane surrounded by the outer edge of the dimples is 300-600 mm². 3 The golf ball according to claim 1 or 3, wherein the following applies:

11. The golf ball according to claim 1 or 3, wherein three or more land pieces of different sizes or shapes are used.

12. A golf ball according to claim 1 or 3, wherein the number of dimples is 200 to 500.

13. A golf ball according to claim 1 or 3, wherein the area coverage ratio of the dimples is 60 to 95%.

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