JP2003169861A - Golf ball - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a golf ball improved in carrying distance and aerodynamical symmetry. <P>SOLUTION: The golf ball is provided with five kinds of dimples from A to E. The E dimple is a specific laterally long dimple and the other dimples are circular dimples. The specific laterally long dimple satisfies conditions (I) and (II) in which a lengthwise dimension Lx is ≥1.4-fold average diameter D of the circular dimple and ≤3.0-fold (I), a crosswise dimension Ln is ≥0.75-fold average diameter D of the circular dimple, and the ratio of the number of the specific laterally long dimples to the total number of dimples is ≥2% and ≤12% (II). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a golf ball, and more particularly to improvement of a golf ball dimple.

[0002]

2. Description of the Related Art A golf ball has about 250 to 550 dimples on its surface. The role of the dimples is to promote the turbulent transition of the boundary layer by disturbing the flow of air around the golf ball during flight of the golf ball to cause turbulent flow separation (hereinafter also referred to as "dimple effect"). . By promoting the transition of turbulent flow, the separation point of air from the golf ball shifts rearward, the pressure resistance decreases, and the flight distance of the golf ball increases. In addition, the promotion of the turbulent flow transition promotes the difference in the separation points between the upper side and the lower side of the golf ball due to backspin, and the lift force acting on the golf ball is increased. A dimple that facilitates turbulent transition, that is, a dimple that can better disturb the flow of air, has excellent aerodynamic characteristics.

Generally, the contour shape of a dimple is circular, but in recent years, attempts have been made to improve the dimple shape intended to improve aerodynamic characteristics, and various golf balls having non-circular dimples have been proposed. For example, JP-A-6
Japanese Patent Publication No. 4-8982 discloses a golf ball in which 7% or more of all dimples have non-circular dimples. Japanese Unexamined Patent Publication No. 8-191905 discloses a golf ball in which the number of dimples having an oval contour is 20% or more of the total number of dimples. JP 2000-
Japanese Patent No. 185113 discloses a golf ball having dimples having an elliptical contour shape, a golf ball having dimples having an oval contour shape, and a golf ball having dimples having a teardrop shape. . The non-circular dimple has a higher dimple effect than the circular dimple.

[0004]

A major concern for golfers is playing a good score and flying a golf ball far.
Many golfers want a golf ball with excellent flight performance. No golf ball has yet been obtained that meets the requirements of golfers. There is still room for improvement regarding the contour shape of non-circular dimples.

On the other hand, another property required for a golf ball is that it has good aerodynamic symmetry.
The good aerodynamic symmetry means that the dependence of the trajectory on the position of the rotation axis of the backspin is small.
Since the non-circular dimple has a directional contour, it may impair the aerodynamic symmetry of the golf ball.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a golf ball excellent in flight distance and aerodynamic symmetry.

[0007]

The invention made to achieve the above object is characterized in that a large number of lateral dimples having a laterally long contour shape and circular dimples having a circular contour shape are provided on the surface. The golf ball has a ratio of the number of horizontally long dimples to the total number of dimples of 2% or more and 12% or less. Here, the specific horizontally long dimple means that the contour shape is horizontally long and satisfies the following (I) and (II). (I) The length dimension Lx is 1.4 times or more and 3.0 times or less of the average diameter D of the circular dimple. (II) The width dimension Ln is the average diameter D of the circular dimples.
0.75 times or more.

In this golf ball, a large flight distance and excellent aerodynamic symmetry are achieved by the synergistic effect of the specific laterally long dimples and the circular dimples.

Specific lateral oblong dimples preferable from the viewpoint of aerodynamic symmetry are: (1) the contour shape is an ellipse or an ellipse, and (2) the contour shape includes a combination of arcs having mutually different dimensions. (3) The contour shape includes a combination of elliptic arcs having mutually different dimensions,
And (4) the contour shape includes a combination of an arc and an elliptic arc.

Preferably, the contour shape of the specific laterally long dimple has no inwardly convex portion. This specific laterally long dimple has little adverse effect on aerodynamic symmetry.

Preferably, the contour shape of the specific laterally long dimple has no apex. This specific laterally long dimple has less adverse effect on aerodynamic symmetry.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, with reference to the drawings,
The present invention will be explained in detail based on the preferred embodiments.

FIG. 1 is a plan view showing a golf ball according to an embodiment of the present invention. Further, FIG. 2 is a front view thereof. The diameter of this golf ball is 40 mm or more 4
It is 5 mm or less, and particularly 42 mm or more and 44 mm or less.
The diameter is 42.67mm from the viewpoint of reducing the air resistance within the range that meets the standards of the US Golf Association (USGA).
It is preferably 42.80 mm or less. The weight of this golf ball is 40 g or more and 50 g or less, and particularly 44 g or more 4
It is 7 g or less. From the viewpoint of increasing the inertia within a range satisfying the standards of the American Golf Association, the mass is 45.00 g or more and 45.
It is preferably 93 g or less.

This golf ball has 156 A dimples, 84 B dimples, 84 C dimples, 18 D dimples, and 18 E dimples. The total number of dimples is 360.
In FIG. 1, types of dimples are indicated by symbols (A to E) for one unit obtained by dividing the spherical surface into six equal parts. The dimple pattern of this golf ball is obtained by spreading the dimple pattern of this unit on the entire spherical surface.

The A dimples, B dimples, C dimples and D dimples are circular dimples. The circular dimple is a dimple whose contour shape is a circle. In the present specification, the term “contour shape” means a shape when an edge, which is a boundary between a virtual spherical surface (a golf ball surface when it is assumed that no dimple exists) and the dimple, is seen from infinity. The diameter of the A dimple is 4.20 mm, and the diameter of the B dimple is 3.9.
0 mm, the diameter of the C dimple is 3.40 mm, and the diameter of the D dimple is 2.50 mm.

FIG. 3 (a) is a plan view showing the E dimples of the golf ball of FIG. 1, and FIG. 3 (b) is shown in FIG.
It is sectional drawing which followed the BB line of (a). As is apparent from FIG. 3, the contour shape of the E dimple has a major axis of 7.9.
It is an ellipse with a diameter of 0 mm and a minor axis of 3.30 mm. The E dimple is a horizontally long dimple, which will be described in detail later, and is also a specific horizontally long dimple.

Reference numeral S in FIG. 3A is a reference line segment. In this specification, "reference line segment"
The term means the longest line segment whose both ends are located on the contour line. Length Lx of this reference line segment S
Is the length dimension. Double arrow L in FIG.
Indicated by n is the widthwise dimension. The width direction dimension Ln is the width of the dimple in the direction orthogonal to the reference line segment S. In the case of a dimple in which the longest one of the line segments whose both ends are located on the contour line can be drawn,
Of these line segments, the one having the shortest dimension Ln in the width direction is the reference line segment S.

In the present specification, the term "horizontally long dimple" means a dimple having a lengthwise dimension Lx larger than a widthwise dimension Ln. A circular dimple or a dimple having a square contour is not a laterally long dimple because the length direction dimension Lx and the width direction dimension Ln are the same.
The horizontally long dimples do not include dimples on which three or more reference line segments can be drawn. A dimple having a regular triangular shape, a dimple having a regular pentagonal shape, a dimple having a regular hexagonal shape, etc. are not laterally long dimples because three or more reference line segments can be drawn.

In the present specification, "specific horizontal oblong dimples"
The term means a horizontally long dimple and also satisfies the following (I) and (II). (I) The length dimension Lx is 1.4 times or more and 3.0 times or less of the average diameter D of the circular dimple. (II) The width dimension Ln is the average diameter D of the circular dimples.
0.75 times or more.

The average diameter D is calculated by averaging the diameters of all circular dimples. For example, N1 circular dimples having a diameter of D1, N2 circular dimples having a diameter of D2, and N3 having a diameter of D3.
The average diameter D of each circular dimple is calculated by the following mathematical formula. D = (D1 × N1 + D2 × N2 + D3 × N3) / (N1
+ N2 + N3)

In the case of the specific laterally long dimple, the lengthwise dimension L
Since x is larger than the widthwise dimension Ln, the dimple effect of disturbing the flow of air is large. From this viewpoint, it is preferable to provide the specific laterally long dimples whose length dimension Lx is 1.16 times or more, further 1.25 times or more, and particularly 2.0 times or more of the width dimension Ln. If the lengthwise dimension Lx is too large with respect to the widthwise dimension Ln, the directionality of the contour shape is increased, and the aerodynamic symmetry of the golf ball may be impaired. From this viewpoint, the lengthwise dimension L
x is 10.0 times the width direction dimension Ln or less, and further 5.0
It is preferable that the specific laterally long dimples having a length not more than twice, especially not more than 3.0 times are provided.

In the case of the specific laterally long dimple, the lengthwise dimension L
Since x is 1.4 times or more the average diameter D of the circular dimples, the dimple effect of disturbing the air flow is large. From this viewpoint, it is preferable to provide the specific laterally long dimples whose lengthwise dimension Lx is 1.5 times or more, and particularly 1.7 times or more, the average diameter D of the circular dimples.
Since the lengthwise dimension Lx of the specific laterally long dimple is set to 3.0 times or less of the average diameter D of the circular dimple,
The good aerodynamic symmetry and appearance of the golf ball is maintained. From these viewpoints, it is preferable to provide the specific laterally elongated dimples whose lengthwise dimension Lx is 2.9 times or less, more preferably 2.8 times or less, and particularly 2.0 times or less of the average diameter D of the circular dimples. .

In the case of the specific laterally long dimple, the width direction dimension Ln
Is 0.75 times or more the average diameter D of the circular dimples, so that the dimple effect of disturbing the air flow is large. From this viewpoint, it is preferable to provide the specific laterally long dimples having the width dimension Ln of 0.80 times or more, and particularly 0.84 times or more of the average diameter D of the circular dimples.

The ratio Rs of the number of specific laterally long dimples to the total number of dimples is set to 2% or more and 12% or less. If this ratio Rs is less than the above range, the dimple effect obtained as the entire golf bow may be insufficient. From this viewpoint, the ratio Rs is more preferably 3% or more, and particularly preferably 4% or more. If the ratio Rs exceeds the above range, the aerodynamic symmetry of the golf ball may be impaired. From this viewpoint, the ratio Rs is more preferably 10% or less, and particularly preferably 7% or less.

The depth F of the specific laterally long dimple is
It is preferably 0.10 mm or more and 0.60 mm or less. Depth F
Within this range, the effect of the specific laterally long dimple that disturbs the air flow is promoted. From this viewpoint, the lower limit of the depth F is more preferably 0.15 mm,
20 mm is particularly preferred. For the same reason, the upper limit of the depth F is more preferably 0.55 mm, particularly preferably 0.50 mm. The depth F is the distance between the phantom spherical surface (indicated by the chain double-dashed line in FIG. 3B) and the deepest part of the dimple, as indicated by the double-headed arrow in FIG. 3B. Is.

Although the golf balls shown in FIGS. 1 and 2 have a single type of specific laterally long dimples (that is, an E dimple having an elliptical contour shape), two or more types of specific laterally long dimples are formed. It may be formed. Usually 1
One or more and four or less types, and particularly one or more and three or less types of specific laterally long dimples are formed. When two or more types of specific laterally long dimples are formed, the ratio Rs of the total number of them to the total number of dimples is set within the above range.

Although only the circular dimples and the specific laterally long dimples are formed in the golf ball shown in FIGS. 1 and 2, other types of dimples may be formed together. Other types of dimples are non-circular but not oblong (for example, regular pentagonal dimples),
And a dimple that is a horizontally long dimple but is not a specific horizontally long dimple. Even when other types of dimples are formed together, the ratio Rc of the number of circular dimples to the total number of dimples is 50% or more, further 70% or more, and particularly 85% or more from the viewpoint of aerodynamic symmetry. Preferably.

The diameter of the circular dimples is set to 2.0 mm or more and 6.0 mm or less, further 2.4 mm or more and 5.5 mm or less, and particularly 2.4 mm or more and 5.0 mm or less. The depth F of the circular dimples is 0.08 mm or more and 0.
35 mm or less, more preferably 0.10 mm or more and 0.30 mm
Below, in particular, it is set to 0.13 mm or more and 0.28 mm or less. The diameter of a circular dimple is the diameter of a circle that is the contour shape of this circular dimple.

From the viewpoint of improving flight distance, it is preferable to form a plurality of types of circular dimples having different diameters or depths F from each other. The number of types of circular dimples is usually 2 or more 1
It is set to 0 or less. The difference in diameter means that the diameter difference is 0.15 mm or more. Dimples of the same type by design but having slightly different diameters due to processing errors are dimples of the same type. The depths F differ from each other means that the depths F differ from each other by 0.005 mm or more. Dimples of the same type by design but having a slightly different depth F due to processing errors are dimples of the same type.

The total number of dimples is preferably 250 or more and 500 or less. If the total number of dimples is less than the above range, the occupation ratio of the dimple area to the surface area of the phantom sphere may be smaller than an appropriate value, and the flight distance may be reduced. From this viewpoint, the total number of dimples is more preferably 280 or more, and particularly preferably 300 or more. When the total number of dimples exceeds the above range, individual dimples become small, which may reduce the flight distance. From this perspective,
The total number of dimples is more preferably 440 or less and 390
The number of pieces or less is particularly preferable.

The total dimple volume is 430 mm^ThreeSince
Top 650 mm^ThreeThe following are preferred. If the sum is less than the above range
If so, the trajectory will be a hop and the flight distance will be insufficient.
There is a risk. From this viewpoint, the total is 440 mm.^Threethat's all
Is more preferable, 450 mm ^ThreeThe above is particularly preferable. Total
If the sum exceeds the above range, the trajectory will be low and the flight distance will be poor.
May be sufficient. From this point of view, the total is 620
mm^ThreeThe following is more preferable, 600 mm^ThreeThe following are especially good
Good The dimple volume is the ball spherical surface and the dimple.
It means the volume of the portion surrounded by the pull surface.

The surface area occupation ratio Y of the dimples is preferably 65% or more and 90% or less. If the surface area occupation ratio Y is less than the above range, the flight performance of the golf ball may be insufficient due to the sparse dimples. From this viewpoint, the surface area occupation ratio Y is more preferably 70% or more,
75% or more is particularly preferable. If the surface area occupation ratio Y exceeds the above range, it becomes difficult to arrange the dimples. From this viewpoint, the surface area occupation ratio Y is more preferably 88% or less,
5% or less is particularly preferable. The surface area occupation ratio Y is the ratio of the total sum of the dimple areas to the area of the virtual spherical surface.

The dimension Lx in the length direction, the dimension Ln in the width direction, the average diameter D, the depth F, the dimple volume, etc. are obtained by actually measuring the golf ball. A golf ball generally has a coating layer on its surface, and it may be difficult to measure the dimensions accurately due to the influence of the coating layer. In the present invention, the golf ball before coating may be actually measured,
The dimensions of the mold may be measured.

FIG. 4 is a plan view showing a specific laterally long dimple 1 formed on a golf ball according to another embodiment of the present invention. Also in this golf ball, circular dimples are formed together with the specific laterally long dimples 1.
The ratio of the number of the specific laterally long dimples 1 to the total number of dimples is 2% or more and 12% or less. The contour shape of the specific horizontally long dimple 1 is an ellipse. An oval is a shape similar to a track on an athletic field, and is a shape in which two semicircles 3 are connected by two parallel line segments 5.

FIG. 5 is a plan view showing a specific laterally long dimple 7 formed on a golf ball according to another embodiment of the present invention. Also in this golf ball, circular dimples are formed together with the specific laterally long dimples 7. The ratio of the number of the specific laterally long dimples 7 to the total number of dimples is 2% or more and 12% or less. The contour shape of the specific horizontally long dimple 7 is formed by a combination of an arc 9 and an elliptic arc 11 (a part of an ellipse). The arc 9 is a semi-circle and the elliptical arc 11 is a semi-ellipse. The diameter of the arc 9 is equal to the minor axis of the elliptical arc 11. This specific horizontal oblong dimple 7 is referred to as “tear shape (tear drop type)” by those skilled in the art.

FIG. 6A is a plan view showing a specific laterally long dimple 13 formed on a golf ball according to still another embodiment of the present invention. Also in this golf ball, circular dimples are formed together with the specific laterally long dimples 13. The ratio of the number of the specific laterally long dimples 13 to the total number of dimples is 2% or more and 12% or less.
The contour shape of the specific horizontally long dimple 13 is the first arc 1
5 and the second circular arc 17 are formed.
The dimensions of the first circular arc 15 and the second circular arc 17 are different from each other. The first arc 15 is a semicircle. The second circular arc 17 is a part of a circle having a larger diameter than the first circular arc 15. A vertex 19 is formed at a connection point between the first circular arc 15 and the second circular arc 17.

FIG. 6B is a plan view showing a specific laterally long dimple 21 formed on a golf ball according to still another embodiment of the present invention. Also in this golf ball, a circular dimple is formed together with the specific laterally long dimple 21. The ratio of the number of the specific laterally long dimples 21 to the total number of dimples is 2% or more and 12% or less.
The contour shape of the specific laterally long dimple 21 is formed by a combination of an arc 23 and an elliptic arc 25. Arc 2
3 is a semicircle. The diameter of the arc 23 is smaller than the minor axis of the elliptical arc 25. A vertex 27 is formed at a connecting point of the arc 23 and the elliptic arc 25.

FIG. 7A is a plan view showing a specific laterally long dimple 29 formed on a golf ball according to another embodiment of the present invention. Also in this golf ball, circular dimples are formed together with the specific horizontally long dimples 29. The ratio of the number of the specific laterally long dimples 29 to the total number of dimples is 2% or more and 12% or less.
The contour shape of the specific horizontally long dimple 29 is the first arc 3
1 and the second arc 33 are formed.
The dimensions of the first arc 31 and the second arc 33 are different from each other. The first arc 31 is a semicircle. The second arc 33 is a part of a circle having a diameter larger than that of the first arc 31. A vertex 35 is formed at a connection point between the first arc 31 and the second arc 33. The contour shape of the specific laterally long dimple 29 is inwardly convex in the vicinity of the apex 35.

FIG. 7B is a plan view showing the specific laterally long dimples 37 formed on the golf ball according to another embodiment of the present invention. Also in this golf ball, a circular dimple is formed together with the specific laterally long dimple 37. The ratio of the number of the specific laterally long dimples 37 to the total number of dimples is 2% or more and 12% or less.
The contour shape of the specific horizontally long dimple 37 is formed by a combination of an arc 39 and an elliptic arc 41. Arc 3
9 is a semicircle. A vertex 43 is formed at a connection point between the arc 39 and the elliptic arc 41. The contour shape of the specific laterally long dimple 37 is inwardly convex in the vicinity of the apex 43.

FIG. 8A is a plan view showing a specific laterally long dimple 45 formed on a golf ball according to another embodiment of the present invention. Also in this golf ball, circular dimples are formed together with the specific laterally long dimples 45. The ratio of the number of the specific laterally long dimples 45 to the total number of dimples is 2% or more and 12% or less.
The contour shape of the specific horizontally long dimple 45 is a rectangle. The specific laterally long dimple 45 has four vertices 47. Two reference line segments S can be drawn on the specific laterally long dimple 45.

FIG. 8B is a plan view showing the specific laterally long dimples 49 formed on the golf ball according to another embodiment of the present invention. Also in this golf ball, circular dimples are formed together with the specific laterally long dimples 49. The ratio of the number of the specific laterally long dimples 49 to the total number of dimples is 2% or more and 12% or less.
The contour shape of the specific horizontally long dimple 49 is a fan shape. The central angle of the sector is less than 60 °. The specific laterally long dimple 49 has three vertices 51. The specific laterally long dimples 49 have an infinite number of longest line segments whose both ends are located on the contour line. Among these line segments, the number of reference line segments S (that is, the one having the shortest width-direction dimension Ln) is two. The reference line segment S coincides with the radius line.

FIG. 8C is a plan view showing the specific laterally long dimples 53 formed on the golf ball according to still another embodiment of the present invention. Also in this golf ball, circular dimples are formed together with the specific laterally long dimples 53. The ratio of the number of the specific laterally long dimples 53 to the total number of dimples is 2% or more and 12% or less.
The contour shape of the specific laterally long dimple 53 is composed of four line segments 55. The specific horizontally long dimple 53 has three vertices 57 that are convex outward and one vertex 59 that is convex inward.
It has and.

Also in each of the golf balls shown in FIGS. 3 to 8, (I) the lengthwise dimension Lx is 1.4 times or more and 3.0 times or less of the average diameter D of the circular dimples, and (II ) The widthwise dimension Ln is the average diameter D of the circular dimples.
Since these golf balls have been achieved at 0.75 times or more, the flight distance and aerodynamic symmetry are excellent.

The specific laterally long dimples shown in each of FIGS. 3 to 7 correspond to any of the following (1) to (4). (1) The contour shape is an ellipse or an ellipse. (2) The contour shape is formed only by a combination of arcs having different dimensions. (3) The contour shape is formed only by a combination of elliptic arcs having different dimensions. (4) The contour shape is composed only of a combination of an arc and an elliptic arc. The contour shape of these specific oblong dimples is smooth,
Therefore, there is little adverse effect on the aerodynamic symmetry.

None of the specific laterally elongated dimples shown in FIGS. 3 to 6 has a portion that is convex inward. The contour shape of these specific laterally long dimples has little directionality. Therefore, it has less adverse effect on aerodynamic symmetry.

None of the specific laterally long dimples shown in FIGS. 3 to 5 has an apex (contacts are excluded). The contour shape of these specific laterally long dimples has particularly little directionality. Therefore, the adverse effect on the aerodynamic symmetry is particularly small.

[0047]

EXAMPLES The effects of the present invention will be clarified below based on Examples, but the present invention should not be construed in a limited way based on the description of the Examples.

[Example 1] An example in which an ionomer resin composition was injected around a core made of solid rubber to form a cover, and a dimple pattern having a plan view of Fig. 1 and a front view of Fig. 2 was provided. A golf ball of No. 1 was obtained. The outer diameter of the ball was 42.74 mm ± 0.03 mm, the compression was 85 ± 2, and the total volume of the dimples was 550.9 mm ³ . Details of dimple specifications,
It is shown in Table 1 below.

Examples 2 to 6 and Comparative Examples 1 to 5 Examples 2 to 6 were carried out in the same manner as Example 1 except that the molding die was changed to the dimple specifications shown in Tables 1 and 2 below.
And golf balls of Comparative Examples 1 to 5 were obtained. The table numbers of the plan view and front view of each golf ball are shown in Table 3 below.

[0050]

[Table 1]

[0051]

[Table 2]

[Flying Distance Test] Forty golf balls of each Example and each Comparative Example were prepared and kept at 23 ° C. On the other hand, a driver (W1) equipped with a metal head was attached to a swing robot manufactured by Golf Laboratories, so that the head speed was about 49 m / s, the launch angle was about 11 °, and the rotation speed of the backspin was about 3000 rpm. Adjusted machine conditions. Then, the golf ball was hit and the flight distance (the distance from the launch point to the drop point) was measured. Of the 40 golf balls, 20 were hit with poles and the other 20 were hit with seams. With pole striking, it is assumed that the great circle on the surface of the golf ball that corresponds to the parting line of the mold for the golf ball is the equator of the globe, and when the plane including the equator is the equator, the rotation axis of the backspin is It is a striking method that exists on the equatorial plane. Seam striking is a striking method in which the rotation axis of the backspin is a straight line connecting the North Pole and the South Pole. The wind during the test was approximately 0.5 m / s or less. The average value of the flight distance is shown in Table 3 below.

[0053]

[Table 3]

In Table 3, the golf ball of each example has a larger flight distance than the golf balls of each comparative example.
Moreover, in the golf balls of the respective examples, the difference in flight distance between the pole hitting and the seam hitting is small. From this evaluation result, the superiority of the present invention is clear.

[0055]

As described above, the golf ball of the present invention is excellent in both flight distance and aerodynamic symmetry. This golf ball can contribute to improving the golfer's score.

[Brief description of drawings]

FIG. 1 is a plan view showing a golf ball according to an embodiment of the present invention.

FIG. 2 is a front view showing the golf ball of FIG.

3 (a) is a plan view showing E dimples of the golf ball of FIG. 1, and FIG. 3 (b) is a sectional view taken along line BB of FIG. 3 (a). .

FIG. 4 is a plan view showing specific laterally long dimples formed on a golf ball according to another embodiment of the present invention.

FIG. 5 is a plan view showing specific laterally long dimples formed on a golf ball according to another embodiment of the present invention.

6 (a) and 6 (b) are plan views showing specific laterally long dimples formed on a golf ball according to another embodiment of the present invention.

7 (a) and 7 (b) are plan views showing specific laterally long dimples formed on a golf ball according to still another embodiment of the present invention.

8 (a), 8 (b) and 8 (c) are plan views showing specific laterally long dimples formed on a golf ball according to still another embodiment of the present invention. .

FIG. 9 is a plan view showing a golf ball according to a second embodiment of the present invention.

FIG. 10 is a front view showing the golf ball of FIG. 9.

FIG. 11 is a plan view showing a golf ball according to a third embodiment of the present invention.

FIG. 12 is a front view showing the golf ball of FIG. 11.

FIG. 13 is a plan view showing a golf ball according to a fourth embodiment of the present invention.

FIG. 14 is a front view showing the golf ball of FIG. 13.

FIG. 15 is a plan view showing a golf ball according to Embodiment 5 of the present invention.

FIG. 16 is a front view showing the golf ball of FIG. 15.

FIG. 17 is a plan view showing a golf ball according to Example 6 of the present invention.

FIG. 18 is a front view showing the golf ball of FIG. 17.

FIG. 19 is a plan view showing a golf ball according to Comparative Example 1 of the present invention.

FIG. 20 is a front view showing the golf ball of FIG. 19.

FIG. 21 is a plan view showing a golf ball according to Comparative Example 2 of the present invention.

22 is a front view showing the golf ball of FIG. 21. FIG.

FIG. 23 is a plan view showing a golf ball according to Comparative Example 3 of the present invention.

FIG. 24 is a front view showing the golf ball of FIG. 23.

FIG. 25 is a plan view showing a golf ball according to Comparative Example 4 of the present invention.

FIG. 26 is a front view showing the golf ball of FIG. 25.

FIG. 27 is a plan view showing a golf ball according to Comparative Example 5 of the present invention.

28 is a front view showing the golf ball of FIG. 27. FIG.

[Explanation of symbols]

A ... A dimple B ... B dimple C ... C dimple D ... D dimple E ... E dimple (specific horizontal oblong dimple) S ... reference line segment Lx ... longitudinal dimension Ln ... Width direction dimension 1, 7, 13, 21, 29, 37, 45, 49, 53 ... Specific laterally long dimple

Claims (5)

[Claims] 1. A horizontal dimple having a laterally long contour shape and a large number of circular dimples having a circular contour shape are provided on the surface, and the lateral dimple satisfies the following (I) and (II). A golf ball in which the ratio of the number of certain specific oblong dimples to the total number of dimples is 2% or more and 12% or less. (I) The length dimension Lx is 1.4 times or more and 3.0 times or less of the average diameter D of the circular dimple. (II) The width dimension Ln is the average diameter D of the circular dimples.
0.75 times or more. 2. The golf ball according to claim 1, wherein the contour shape of the specific horizontally long dimple is an ellipse or an ellipse. 3. The contour shape of the specific laterally long dimples,
The golf ball according to claim 1, comprising a combination of arcs having different dimensions, a combination of elliptical arcs having different dimensions, or a combination of arcs and elliptic arcs. 4. The golf ball according to claim 1, wherein the contour shape of the specific horizontally long dimple has no inwardly convex portion. 5. The golf ball according to claim 1, wherein the contour shape of the specific laterally long dimple has no apex.