JP2000102626A - Golf ball - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase carry by dint of enhancing a dimple effect which disturbs flow of air and improving an aerodynamic characteristic by arranging dimples closely so as not to generate specific numbers of land parts whose areas are relatively large among the land parts, i.e., parts except for the dimples on a surface of a golf ball. SOLUTION: A spherical surface of a golf ball whose total of dimples 1 are set to, for example, 432 and diameters of the dimples 1 are set from 4.30 mm to 2.70 mm and areas of the dimples 1 are set from 14.5 mm2 to 5.7 mm2 is divided into, for example, 20 pieces of units. A rectangle 10 whose short side's size is more than 0.4 mm and area is more than 0.8 mm2 which is indicated by painting in black is provided in one of the units. Excellent dimple effect can be obtained by setting the land parts which can from rectangles to no more than 40 portions on the whole surface of sphere of the golf ball when the above processes are done on the golf ball without a large circle passage which does not cross with the dimples completely on a parting line which is formed when the golf ball is formed.

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 a golf ball in which the arrangement of dimples is improved and the dimples are densely arranged to improve flight performance.

[0002]

2. Description of the Related Art Generally, 280 to 540 dimples are provided on the surface of a golf ball. The role of the dimples is to improve the aerodynamic characteristics of the golf ball during flight of the golf ball by disturbing the flow of air, thereby extending the flight distance.

[0003] In view of the role of the dimples, it can be said that the closer the dimples are arranged on the surface of the golf ball, the greater the effect of disturbing the flow of air and the longer the flight distance. From this point of view, various proposals have been made on dimple arrangement methods. For example, the present applicant also discloses in Japanese Patent Application Laid-Open No. 62-192181 that a new dimple having an area equal to or larger than the average area of one dimple is formed on a land portion (land portion) which is a portion other than the dimple on the surface of the golf ball. A golf ball formed in an impossible size is proposed.

That is, the area of the land portion between the dimples is reduced, in other words, the dimples are densely arranged to enhance the aerodynamic characteristics. Although the golf ball is commercially available from the present applicant, due to its excellent flight performance,
It has become popular among many golfers.

[0005]

However, there is a very large demand for the golfer's flight distance.
In particular, in recent years, as the number of female golfers having lower muscular strength than men has rapidly increased, golf balls having a longer flight distance have been desired. The present invention has been made in view of the above circumstances, and is described in Japanese Patent Application Laid-Open No. 62-192181.
(U.S. Pat. No. 4,813,677) aims to improve the arrangement of dimples proposed in U.S. Pat.

[0006]

That is, the present invention reduces the area of a land portion surrounded by dimples that are further adjacent to the golf ball described above. While the land portion is not formed, the present invention also limits the land portion having a small area of about 1/5 or less than the average area of the dimple to 40 places or less on the entire surface of the golf ball,
The area of the remaining land is further reduced, and the dimples are densely arranged.

More specifically, the present invention relates to a golf ball having a dimple and a land portion other than the dimple on the surface, wherein the land portion having a relatively large area among the land portions satisfying the following conditions is used. A golf ball characterized in that dimples are densely arranged so that only 40 or less positions are formed on the surface of the golf ball. That is, a land portion that can form a rectangle that satisfies the above three conditions, has a short side of 0.4 mm or more in length, an area of 0.8 mm ² or more, and does not include some or all of the dimples inside. Is limited to 40 places or less, and the other lands are lands having areas smaller than the above conditions. Most of the lands limited to 40 places or less have a short side of 0.4 mm and an area approximating to 0.8 mm ² which satisfies the above-mentioned conditions. The size is set to be equal to or smaller than a size that cannot form a dimple having a new area larger than the average area.

There are a plurality of land portions satisfying the above-mentioned conditions, and the plurality of land portions may be continuous or partially overlapped. Also included in the present invention,
The number of lands is counted as one.

[0009] Further, a great circle path without dimples is formed on a parting line which is a joining portion of a pair of upper and lower mold halves during molding of a golf ball. Therefore, there are many land portions that satisfy the above conditions near the great circle passage. In the present invention, lands where a rectangle that meets the above condition and intersects with the great circle passage are not counted.

[0010] However, the present applicant has filed Japanese Patent Application No. 2-337564.
It is possible to create a golf ball having no great circle path at all by the method proposed in the above item, and in such a golf ball, a rectangle corresponding to the above condition can be formed on the entire spherical surface of the golf ball. It is desirable that the number of land portions is 40 or less.

Although the shape of the land is defined as a rectangle, it is not strictly a rectangle because the surface of the golf ball is a curved surface, and thus the sides are curved. However, in the present invention, these are also assumed to be approximately rectangular.

[Operation] The diameter of the dimple is usually 2.50.
mm to 4.50 mm, so that the minimum area of a normal dimple is approximately 5 mm ² . Therefore, the above 4
0 land portion of the area 0.8mm ^2, which is limited to places is,
It is 1/5 or less of the minimum dimple area, which is an extremely small area. The lands that can form a rectangle having this small area are limited to 40 places or less, and the areas of the lands surrounded by many other dimples are set to be smaller, so that the dimples are arranged extremely densely. .

The land portion, especially a smooth land portion capable of forming a rectangle satisfying the above-mentioned conditions, reduces the effect of disturbing the air flow during flight, and reduces the number of lands and increases the size. Since the area of many lands is small enough not to weaken the dimple effect, dimples having the effect of disturbing the flow of air are densely arranged, so that aerodynamic characteristics during flight can be improved, It is possible to dramatically increase the flight distance.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments shown in the drawings. As examples of the present invention, golf balls of the first and second examples having the dimple specifications shown in Table 1 were produced.

[0015]

[Table 1]

FIGS. 1 and 2 show the golf ball of the first embodiment.
1 is a front view, and FIG. 2 is a plan view. The go
The ruff ball has a total of 432 dimples,
Pull 1 has five types of A, B, C, D and E as shown in Table 1.
The diameter of these dimples 1 is 4.30 mm to 2.70.
mm range and the area is 14.5mm²~ 5.7mm
²The other specifications are as shown in Table 1.

FIG. 2 divides the spherical surface of the golf ball of the first embodiment into 20 units, and shows only one of them. In this one unit, a rectangle 10 filled in black in the figure has a short side of 0.4 in length.
mm, the area is 0.8 mm ² or more, and the shape is a rectangle that does not include dimples inside. The rectangle has a short side of 0.7 mm and an area of 1.9 mm ² . Therefore, it is naturally smaller than the area of the dimple A having the area of 14.5 mm ² , that is, about 1/7.

As shown in FIG. 2, the above-mentioned rectangle 10 can be formed in one unit, and only one land portion 2 corresponding to the condition that a land portion having an area equal to or greater than the dimple of the average area cannot be formed. The dimples 1 are arranged so as to exist. Since the 20 units have the same dimple arrangement, there are 20 lands 2 on the entire ball surface of the golf ball. The land portion 3 between the other dimples 1 is a land portion having a smaller area, which does not correspond to the condition of the land portion 2.

The rectangle that does not include a part or all of the dimple is the rectangle 10 shown in FIG. On the other hand, the rectangle including a part of the dimple therein is, for example, a rectangle 10 ′ as shown in FIG. The rectangle including all the dimples therein is, for example, a rectangle 10 ″ as shown in FIG.

In the present invention, as shown in FIG. 6, a rectangle 10 having a short side length of 0.4 mm or more, an area of 0.8 mm ² or more, and not including some or all of the dimples.
Are also counted as one location where two or more lands can be formed. Furthermore, the land portions 2 where the rectangles 10 shown in FIG. 7 overlap each other are also counted as one place. Also in the land portion 2, the dimple having an area larger than the dimple having the average area is smaller than a size that cannot be formed.

In the golf ball of the first embodiment, since a dimple cannot be formed on a parting line formed at the time of molding, there is a great circle passage 5 which does not intersect the dimple at all. Accordingly, there are many lands 2 near the great circle passage 5 where a rectangle corresponding to the above condition exists, but in the present invention, the land where a rectangle intersecting the great circle passage 5 is formed is counted. I haven't.

In the present invention, in the golf ball without the great circle passage 5, the lands 2 capable of forming a rectangle satisfying the above conditions are counted on the entire ball surface of the golf ball, and the number of the lands 2 is 40. It is as follows.

Of the dimple specifications shown in Table 1 above, the diameter is the distance between the two contact points a and b of the common tangent line L drawn at both ends of the dimple 1 shown in FIG. The length of a line segment from L to the deepest part of the dimple, which is the distance between points c and d in the figure. The area is the area of the circle with the above diameter, and the volume is the volume of the hatched portion in the figure,
The total volume is the sum of the volumes of all dimples.

FIGS. 9 and 10 show a golf ball according to a second embodiment of the present invention. FIG. 9 is a front view, and FIG. 10 is a plan view. The dimple specifications of the golf ball are also shown in Table 1 above.
The total number of dimples is 420, A,
B set, C, D, equipped with five dimples 1 E, the dimples first diameter is set in the range of 4.30Mm～2.80Mm, area in the range of 14.5mm ² ~6.2mm ² are doing.

FIG. 10 shows one unit of the golf ball surface divided into 20 units, similar to FIG. 2 of the first embodiment, and the short side included in each unit. The rectangle 10 having a length of 0.4 mm or more and an area of 0.8 mm ² or more and having no dimples therein is shown in black. As shown in the figure, there are 1.6 lands 2 that can form the above-described rectangle in one unit.

That is, the 1.6 land portions 2 are 2
One point indicated by -a, one-half point indicated by 2-b,
1/10 points indicated by c, total (1 + 1/2 + 1/10)
The above is 1.6 places. Thus, since there are 1.6 places in one unit, there are 32 lands 2 on the entire surface of the ball of the golf ball. The lengths and areas of the short sides of the lands 2-a to 2-c are as shown in Table 2 below.

Table 2 Length and Area of Short Side of Land Part Length of Short Side (mm) Area (mm ² ) Land 2-a 0.4 0.8 Land 2-b 1.0 2.2 Land Part 2-c 1.0 2.2

In order to confirm the effects of the golf ball of the present invention, golf balls of first to fourth comparative examples having dimple specifications shown in Table 1 were prepared.

The golf ball of the first comparative example is a golf ball having 432 total dimples.
The plan view is shown in FIG. FIG. 12 shows FIG.
10, the length of the short side of one of the 20 divided units is 0.4 mm or more, the area is 0.8 mm ² or more, and no dimple is contained inside. The rectangle 10 is shown in black.
As shown in the drawing, in the golf ball of the first comparative example, there are four land portions 2 that can form the rectangle 10 in one unit.
There are two places (2 + 1 / 2.4).

That is, two lands 2-x completely included in one unit, four lands 2-y which halves an adjacent unit, and a total of four lands 2-y in one unit. The land portion 2 is provided. Thus, there are 80 golf ball surfaces as a whole. As described above, in the golf ball of the first comparative example, there are approximately four times as many lands as those described above in the first embodiment of the present invention, and approximately twice as many lands as in the second embodiment.
The dimple pattern of the golf ball of the first comparative example is the same as the golf ball of the fourth example described in Japanese Patent Application Laid-Open No. Sho 62-192181.

The golf ball of the second comparative example is a golf ball having a total of 420 dimples. FIG.
A plan view is shown in FIG. FIG. 14 shows the golf ball surface 2
0 to the length of the shorter side included in one unit of the divided unit is 0.4mm or more, the area is not less 0.8 mm ² or more, shows a rectangular 10 free of dimples therein. As shown in the figure, lands 2 where the above-described rectangle 10 can be formed are formed in 9.1 places (6 + 1/2) in one unit.
6 + 1/10) exists.

That is, six land portions 2-x completely included in one unit, six land portions 2-y half-split with the adjacent unit, and a land portion 2- 1/10 of a rectangle exist. z is one place, and there are a total of 9.1 places. Therefore, one land portion 2 is formed on the entire surface of the golf ball.
There are 82. Therefore, there are approximately nine times as many land portions as in the first embodiment of the present invention, and approximately six times as many as in the second embodiment. The dimple pattern of the golf ball of the second comparative example is described in Japanese Patent Application Laid-Open No. 62-19218.
It is the same as the golf ball of the third embodiment of No. 1.

Since the golf balls of the first comparative example and the second comparative example are the golf balls according to the above-mentioned Japanese Patent Application Laid-Open No. 62-192181, they have land portions capable of forming dimples having an area larger than the average area of the dimples. Not
In other words, the golf ball has dimples arranged very densely. However, the number of lands that can form the above-mentioned rectangle is several times or more as compared with the golf balls of the first and second embodiments of the present invention. It cannot be said that the golf ball has the arrangement.

The golf ball of the third comparative example is a golf ball having a total of 392 dimples. FIG.
A plan view is shown in FIG. In FIG. 16, the length of the short side included in one of the units obtained by dividing the surface of the golf ball into 20 pieces is 0.4 mm or more, the area is 0.8 mm ² or more,
Inside, a rectangle 10 not including a dimple is shown. As shown in FIG.
0 can be formed at 11 places (10 + 1/2 ·).
2) Exists.

That is, there are 10 land portions 2-x completely included in one unit, and two land portions 2-y that half overlap with an adjacent unit, and a total of 11 land portions exist. Accordingly, 220 lands 2 satisfying the above conditions exist on the entire golf ball surface. As described above, the number of the land portions 2 of the golf ball of the third comparative example is 11 times as large as that of the first embodiment of the present invention and about 7 times that of the second embodiment. The dimple pattern of the golf ball of the third comparative example is a pattern that has been used for golf balls since ancient times, and is a pattern that is still frequently used.

The golf ball of the fourth comparative example is a golf ball having a total of 408 dimples. FIG.
A plan view is shown in FIG. FIG. 18 shows a rectangle 10 having a short side length of 0.4 mm or more, an area of 0.8 mm ² or more, and no dimple inside, which is included in one unit of the golf ball surface divided into 12 parts. Is shown. As shown in the figure, there are five land portions (4 + 1 / 2.2) where the rectangle 10 can be formed in one unit.

That is, there are four lands 2-x completely included in one unit, and two lands 2-y which halves an adjacent unit, and there are a total of five lands. Therefore, on the entire golf ball surface, the land portion 2 corresponding to the above condition has a size of 5 × 12 = 60 = 60.
There are two places. As described above, the golf ball of the fourth comparative example has the smallest total number of land portions 2 as compared with the golf balls of the first to third comparative examples.

The land portion of the first comparative example shown in FIG.
The land portion of the second comparative example shown in FIG.
The length and area of the short side of the land portion of the comparative example and the land portion of the fourth comparative example shown in FIG. 18 are as shown in Table 3 below.

Table 3 Length and Area of Short Side of Land Part Length of Short Side (mm) Area (mm ² ) First Comparative Example Land 2-a 0.7 1.6 Land 2-b 0.8 1.8 Land part 2-c 0.7 1.6 Land part 2-d 0.7 1.6 Land part 2-e 0.7 1.6 Land part 2-f 0.9 2.0 Second comparison Example Land part 2-a 1.1 2.9 Land part 2-b 0.6 1.5 Land part 2-c 1.1 1.5 Land part 2-d 0.7 2.0 Land part 2-e 1.1 1.5 Land part 2-f 0.7 2.0 Land part 2-g 0.6 1.5 Land part 2-h 1.1 2.9 Land part 2-i 0.6 1.5 Land part 2-j 1.1 1.5 Land part 2-k 0.6 1.5 Land part 2-l 1.1 1.5 Land part 2-m 0.7 2.0 Third comparative example Land part 2-a 0.6 1 5 Land 2-b 0.6 1.6 Land 2-c 0.5 1.4 Land 2-d 0.6 1.6 Land 2-e 0.6 1.7 Land 2-f 0.6 1.5 Land part 2-g 0.6 1.6 Land part 2-h 0.6 1.5 Land part 2-i 0.6 1.5 Land part 2-j 0.6 1.6 Land 2-k 0.6 1.5 Land 2-1-1 0.5 1.4 Fourth Comparative Example Land 2-a 0.4 0.9 Land 2-b 0.9 0.8 Land 2-c 0.4 0.9 Land portion 2-d 0.5 1.2 Land portion 2-e 0.4 1.2 Land portion 2-f 0.4 0.8

The golf balls of the first and second embodiments and the first to fourth comparative examples are thread wound balls having a balata cover and a liquid center, and have the same structure and composition. The outer diameter is 4
Standardized to 2.70 ± 0.03mm, compression 9
It is unified to 5 ± 2.

[Experimental Examples] Experimental examples of the golf balls of the first and second embodiments and the first to fourth comparative examples will be described below. The first and second embodiments and the first comparative example,
The golf balls of the second comparative example, the third comparative example, and the fourth comparative example were subjected to a flight distance test under a condition of a head speed of 45 m / s with a driver (W1) using a swing robot manufactured by "Trutemper". . Spin is 3500 ± 300rp
m and the machine conditions were adjusted so that the ball launch angle was 10 ± 0.5 degrees. Table 4 below shows the average of the results of experiments for 20 balls.

[0042]

[Table 2]

In Table 4, the flight distance is the distance from the ball launch point to the ball resting place. The trajectory height is the elevation angle of the trajectory highest point viewed from the ball launch point.

As shown in Table 4, the golf balls of the first embodiment and the second embodiment according to the present invention are the golf balls of the first comparative example, the second comparative example, the third comparative example, and the fourth comparative example. It was confirmed that the golf ball had a longer flight time and a longer flight distance than the ball. Among the golf balls of the first to fourth comparative examples, the golf ball of the fourth comparative example having the smallest number of lands provided good results in all of the flight distance, trajectory height, and flight time.

This is because dimples disturb the flow of air and improve the aerodynamic characteristics at the positions where the land portions 2 are relatively large and have a smooth shape enough to form the rectangle 10. Therefore, as the location of the land portion 2 increases, the aerodynamic characteristics of the golf ball during flight decrease, and conversely, the land portion 2
It can be considered that as the number of existing portions is reduced, the dimple effect is not weakened by the presence of the land portion, so that the aerodynamic characteristics are improved and the flight distance is increased.

[0046]

As is apparent from the above description, in the golf ball according to the present invention, the area of the portion surrounded by the adjacent dimples other than the dimples existing on the surface of the golf ball is reduced, and the relatively large area is obtained. A land part that can form a rectangle that has a short side length defining the land part of at least 0.4 mm, an area of at least 0.8 mm ² , and that does not include part or all of the dimple (in this case, the average area of the dimple The number of lands (area of about 1/5 or less) is also 40
The dimples are extremely densely arranged so as to be less than two places.

As described above, the location of the land part having a relatively large area is limited to a small number of 40 places or less, and the area itself of the land part having a relatively large area is also smaller than the area of the land part of the same kind as the conventional land part. Since the area is much smaller in comparison, the dimple effect that disturbs the flow of air is not weakened by the presence of the land portion, so that the aerodynamic characteristics can be improved by the dimple effect and the flight distance can be increased.

[Brief description of the drawings]

FIG. 1 is a front view of a golf ball according to a first embodiment of the present invention.

FIG. 2 is a plan view of the golf ball of the first embodiment.

FIG. 3 is a schematic view showing a relationship between a dimple and a land portion.

FIG. 4

FIG. 5

FIG. 6

FIG. 7

FIG. 8 is a drawing for explaining the specifications of dimples.

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

FIG. 10 is a plan view of a golf ball according to a second embodiment.

FIG. 11 is a front view of a golf ball of a first comparative example.

FIG. 12 is a plan view of a golf ball of a first comparative example.

FIG. 13 is a front view of a golf ball of a second comparative example.

FIG. 14 is a plan view of a golf ball of a second comparative example.

FIG. 15 is a front view of a golf ball of a third comparative example.

FIG. 16 is a plan view of a golf ball of a third comparative example.

FIG. 17 is a front view of a golf ball of a fourth comparative example.

FIG. 18 is a plan view of a golf ball of a fourth comparative example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Dimple 2 Land part 5 Great circle passage 10 Rectangle

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[Procedure amendment]

[Submission date] November 18, 1999 (1999.11.
18)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction contents]

[Document Name] Statement

[Title of the Invention] Golf ball

[Claims]

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 an improvement in dimple arrangement on a golf ball surface.

[0002]

2. Description of the Related Art Generally, 280 to 540 dimples are provided on the surface of a golf ball. The role of the dimple is to improve the aerodynamic characteristics by disturbing the flow of air during the flight and to increase the flight distance of the golf ball.

[0003] Since the dimples improve the aerodynamic characteristics as described above, a golf ball having dimples densely arranged on its surface generally has better flight performance than a golf ball sparsely arranged. From this point of view, various proposals have conventionally been made on dimple arrangement methods. For example,
The present applicant has disclosed Japanese Patent Application Laid-Open No. 62-192181 (U.S. Pat.
No. 812677) proposes a golf ball having a land portion (land portion) other than the dimples on the surface of the golf ball, the size of which is such that a new dimple having an area larger than the average area of one dimple cannot be formed. ing. In this golf ball, the aerodynamic characteristics are enhanced by reducing the area of the land portion, that is, by densely disposing the dimples. This golf ball is marketed by the present applicant, but has been popular with many golfers because of its excellent flight performance.

[0004]

However, there are very large demands on the golfer's flight distance.
Particularly, in recent years, with the sudden increase in the number of female golfers having lower muscular strength than males, golf balls having a longer flight distance have been desired.

The present invention has been made in view of the above circumstances, and has as its object to improve the arrangement of dimples proposed in the above-mentioned Japanese Patent Application Laid-Open No. 62-192181 and to extend the flight distance of a golf ball. .

[0006]

The invention made to achieve the above object has a dimple and a land portion other than the dimple, and the surface thereof corresponds to a parting line of a molding die. A golf ball in which a great circle passage is not formed, a rectangle having a short side length of 0.4 mm or more, an area of 0.8 mm ² or more, and not including some or all of the dimples therein. The number of lands that can be formed is 40 or less on the entire surface,
The land area having the largest area among the land areas is a golf ball characterized in that a new dimple having an area larger than the average area of the dimples cannot be formed.

[0007] The golf ball of the present invention has a smaller land area than the conventional golf ball described above. The land portion of the conventional golf ball has a size such that a new dimple having an area equal to or larger than the average area of the dimple is not formed.
The land portion having a small area of about / 5 or less is limited to 40 places or less on the entire surface of the golf ball, the area of the remaining land portion is further reduced, and the dimples are densely arranged.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the golf ball of the present invention, dimples are densely arranged, and the number of lands forming a rectangle satisfying all of the following conditions (1) to (3) is four.
No more than 0 places. (1) The length of the short side of the rectangle is 0.4 mm or more. (2) The area is 0.8 mm ² or more. (3) Do not include some or all of the dimples inside. In the present invention, the number of lands that can form a rectangle satisfying the above three conditions is limited to 40 or less, and the other lands are lands smaller than the above conditions. 40 land portion which is limited to less than places are mostly short side 0.4 mm, but the area has a shape approximated to 0.8 mm ^2, even land portion of the maximum area, the average area or the area of the dimples The size is such that a new dimple cannot be formed.

There are a plurality of land portions satisfying the above conditions, and when the plurality of land portions are continuous or partially overlapped, one continuous land portion includes a plurality of land portions satisfying the above condition. In this case, the number of lands is counted as one.

A golf ball is formed by a pair of upper and lower mold halves. In general, a great circle path without dimples is formed in a portion of the golf ball surface corresponding to a joining portion (parting line) of a mold. But,
By the method proposed by the present applicant in Japanese Patent Application No. 2-337564, it is possible to produce a golf ball having no great circle path at all. The present invention relates to a golf ball having no such great circle path corresponding to a parting line. In a golf ball having a great circle passage corresponding to a parting line, lands that can form a rectangle satisfying the above three conditions are counted in a region excluding the great circle passage, and the number of lands is 40 or less. Is done.

Since the surface of the golf ball is a curved surface, the figure drawn on the surface of the golf ball has a three-dimensional shape,
Each side is a curve. Although this graphic is not strictly rectangular, it is approximately referred to herein as a rectangle.

The diameter of the dimple is usually 2.50 mm to 4.5 mm.
Thus, the minimum area of a normal dimple is approximately 5 mm ² . A land portion having an area of 0.8 mm ² is 1/5 or less of the minimum dimple area, and is an extremely small area. The number of lands on which this small area rectangle can be formed is limited to 40 or less, and the dimples are extremely densely arranged because the area of the other many lands is set smaller.

The land, particularly a smooth land which can form a rectangle satisfying the above conditions, reduces the effect of disturbing the flow of air during flight. Since the number of the lands is reduced and the area of the majority of the lands is small enough not to weaken the dimple effect, dimples having the effect of disturbing the air flow are densely arranged. Therefore, the aerodynamic characteristics during flight are improved, and the flight distance is dramatically improved.

[Experimental Examples] Hereinafter, the present invention will be described in detail based on experimental examples shown in the drawings. In order to confirm the effects of the present invention,
Golf balls of the first experimental example and the second experimental example having the dimple specifications shown in Table 1 were produced.

[0015]

[Table 1]

FIG. 1 is a front view showing a golf ball of a first experimental example, and FIG. 2 is a plan view thereof. In this golf ball, the total number of dimples is 432, and dimples 1 are five types of A, B, C, D and E as shown in Table 1, and the diameter of these dimples 1 is 4.30 mm to 2.70.
mm, and the area is 14.5 mm ^{2 to} 5.7 mm ²
The other specifications are as shown in Table 1.

In FIG. 2, the rectangle 10 filled in black has a short side of 0.4 mm or more and an area of 0.8 m.
m is ² or more, and a rectangular free part of the dimples and the whole inside. Note that, in this figure, 1 is the case where the spherical surface of the golf ball is divided into 20 units.
A rectangle is shown for only units. The rectangle has a short side of 0.7 mm and an area of 1.9 mm ² . Therefore, the area of this rectangle is about 1/7 of 14.5 mm ² which is the area of the dimple A.

As shown in FIG. 2, a rectangle 10 can be formed in one unit, and a land portion 2 which satisfies the condition that a new dimple having an area larger than the average area of the dimple cannot be formed is formed in one unit. There are only two places. 2
Since each of the zero units has the same dimple arrangement, there are twenty lands 2 on the entire ball surface of the golf ball. The other land 3 is the land 2
Is a land portion having a smaller area, which does not correspond to the condition (1).

The rectangle not including all or part of the dimple is a rectangle 10 as shown in FIG. In contrast, a rectangle that contains a portion of the dimple inside
For example, a rectangle 10 'as shown in FIG. Also, the rectangle that contains all the dimples inside,
For example, a rectangle 10 ″ as shown in FIG.

In the present invention, as shown in FIG. 6, the length of the short side is 0.4 mm or more, the area is 0.8 mm ² or more,
The land portion 2 on which two or more rectangles 10 that do not include part or all of the dimple can be formed is also counted as one place. Also, the land portions 2 where the rectangles 10 overlap each other as shown in FIG. 7 are counted as one location. These lands 2 also have such a size that new dimples having an area larger than the average area of the dimples cannot be formed.

Since no dimple can be formed on the parting line of the mold at the time of molding, the golf ball of the first experimental example has a great circle passage 5 which does not intersect the dimple at all. The present invention relates to a golf ball in which there is no great circle path 5 that does not intersect the dimple at all. However, for the sake of convenience, the effect of the present invention is confirmed by a golf ball in which there is a great circle path 5 that does not intersect the dimple at all.

In Table 1 described above, the diameter is the distance between the two contacts a and b of the common tangent line L drawn at both ends of the dimple 1 shown in FIG. Further, the depth is the length of a line segment descending from the tangent L to the deepest part of the dimple, and is the distance between the midpoints c and d shown in FIG. The area is the area of a circle having the above-mentioned diameter, the volume is the volume of a portion shown by oblique lines in the figure, and the total volume is the sum of the volumes of all dimples.

FIG. 9 is a front view showing a golf ball of a second experimental example, and FIG. 10 is a plan view thereof. Table 1 shows the dimple specifications of the golf ball. In this golf ball, the total number of dimples is 420,
A, B, C, equipped with a five dimples 1 D and E, of dimples first diameter is in the range of 4.30Mm～2.80Mm, area in the range of 14.5mm ² ~6.2mm ² is there.

In FIG. 10, one of the units obtained by dividing the surface of the golf ball into 20 units is shown below.
The short side length is 0.4 mm or more and the area is 0.8 mm ²
As described above, the rectangle 10 having no dimple therein is painted black. As is apparent from FIG.
In each unit, there are 1.6 lands 2 that can form a rectangle.

That is, the 1.6 land portions 2 are 2
One point indicated by −a, １ ／ point indicated by 2-b, and 1/10 point indicated by 2-c, a total of (1 + 1 /
2 + 1/10), which is 1.6 places. Therefore,
On the entire ball surface of the golf ball, the land 2 is 32
There are two places. The lengths and areas of the short sides of the lands 2-a to 2-c are as shown in Table 2 below.

Table 2 Length and Area of Short Side of Land Part Length of Short Side (mm) Area (mm ² ) Land 2-a 0.4 0.8 Land 2-b 1.0 2.2 Land Part 2-c 1.0 2.2

The golf ball of the third experimental example is a golf ball having 432 dimples. A front view is shown in FIG. 11 and a plan view is shown in FIG. In FIG. 12, 2
Regarding one of the units divided into 0 units, the length of the short side existing inside the unit is 0.4 mm or more, the area is 0.8 mm ² or more, and the inside contains dimples. The missing rectangle 10 is painted black. As shown in the figure, in the golf ball of the third experimental example, four land portions 2 where a rectangle 10 can be formed in one unit are formed.
(2+ (1/2) .4) exist.

That is, two land portions 2-x completely included in one unit and four land portions 2-y which halve an adjacent unit and a half, and a total of four land portions 2-x are included in one unit. The part 2 exists. Therefore, 80 lands 2 exist on the entire golf ball surface. As described above, in the golf ball of the third experimental example, the land portion corresponding to the above condition is substantially the same as that of the first experimental example.
It is twice as many as the second experimental example. This third
The dimple pattern of the golf ball of the experimental example is the same as that of the golf ball of the fourth embodiment described in Japanese Patent Laid-Open No. 62-192181.

The golf ball of the fourth experimental example is a golf ball having a total of 420 dimples, and a front view is shown in FIG. 13 and a plan view is shown in FIG. FIG. 14 relates to one of the units obtained by dividing the surface of the golf ball into 20 pieces, and has a short side of 0.4 mm or more, an area of 0.8 mm ² or more, and no dimple inside. The rectangle 10 is painted black. As shown in the drawing, lands 2 where the above-described rectangle 10 can be formed are formed in 9.1 places (6+ (1/2) .6 + 1/1 /) in one unit.
0) Exists.

That is, there are six land portions 2-x completely included in one unit, six land portions 2-y which halves the adjacent unit, and a land portion 2 having 1/10 of a rectangle. -Z is one place, and there are a total of 9.1 places. Therefore, there are 182 lands 2 on the entire surface of the golf ball. Therefore, the land portion 2 is about 9 times as large as the first experimental example, and about 6 times as large as the second experimental example.
There are times. The dimple pattern of the golf ball of the fourth experimental example is the same as the golf ball of the third embodiment of the above-mentioned Japanese Patent Application Laid-Open No. 62-192181.

As described above, since the golf balls of the third and fourth experimental examples are golf balls according to Japanese Patent Application Laid-Open No. 62-192181, new dimples having an area larger than the average area of the dimples are formed. The golf ball does not have a land portion that can be used, in other words, a dimple is arranged very densely. However, the number of lands on which a predetermined rectangle can be formed is several times or more as compared with the golf balls of the first and second experimental examples, and when compared with these, the dimples are densely arranged. It is not a good golf ball.

The golf ball of the fifth experimental example is a golf ball having a total of 392 dimples, and a front view is shown in FIG. 15 and a plan view is shown in FIG. FIG. 16 shows one unit of the surface of the golf ball divided into 20 units, in which the short side length is 0.4 mm or more and the area is 0.8.
In mm ² or more, rectangles 1 inside does not contain dimples
0 is painted black. As shown in the figure, there are 11 land portions 2 (10+ (1/2) .2) where a rectangle 10 can be formed in one unit.

That is, there are 10 land portions 2-x completely included in one unit, and two land portions 2-y which half extend over an adjacent unit, and there are a total of 11 land portions. Accordingly, 220 lands 2 satisfying the above conditions exist on the entire golf ball surface. As described above, the number of the land portions 2 of the golf ball of the fifth experimental example is as large as 11 times that of the first experimental example and about 7 times that of the second experimental example. The dimple pattern of the golf ball of the fifth experimental example is a pattern that has been used for golf balls since ancient times, and is a pattern that is still frequently used.

The golf ball of the sixth experimental example is a golf ball having a total of 408 dimples. FIG.
A plan view is shown in FIG. FIG. 18 shows one unit of the golf ball surface divided into 12 parts.
A rectangle 10 having a short side of 0.4 mm or more, an area of 0.8 mm ² or more, and no dimple inside is filled in black. As shown in the figure, there are five land portions 2 where the rectangle 10 can be formed in one unit.
(4+ (1/2) .2) exists.

That is, there are four lands 2-x completely included in one unit, and two lands 2-y which halves an adjacent unit, and a total of five lands exist. . Therefore, on the entire golf ball surface, the land portion 2 corresponding to the above condition is 5 × 12 = 60.
There are 60 locations. Thus, the golf ball of the sixth experimental example has a smaller total number of land portions 2 than the golf balls of the third to fifth experimental examples.

Table 3 below shows the lengths and areas of the short sides of the lands in the third, fourth, fifth, and sixth experimental examples.

Table 3 Length and Area of Short Side of Land Part Length of Short Side (mm) Area (mm ² ) Third Experimental Example Land part 2-a 0.7 1.6 Land part 2-b 0.8 1.8 Land part 2-c 0.7 1.6 Land part 2-d 0.7 1.6 Land part 2-e 0.7 1.6 Land part 2-f 0.9 2.0 Fourth experiment Example Land part 2-a 1.1 2.9 Land part 2-b 0.6 1.5 Land part 2-c 1.1 1.5 Land part 2-d 0.7 2.0 Land part 2-e 1.1 1.5 Land part 2-f 0.7 2.0 Land part 2-g 0.6 1.5 Land part 2-h 1.1 2.9 Land part 2-i 0.6 1.5 Land part 2-j 1.1 1.5 Land part 2-k 0.6 1.5 Land part 2-1 1.1 1.5 Land part 2-m 0.7 2.0 Fifth experimental example Land part 2-a 0.6 1 5 Land 2-b 0.6 1.6 Land 2-c 0.5 1.4 Land 2-d 0.6 1.6 Land 2-e 0.6 1.7 Land 2-f 0.6 1.5 Land portion 2-g 0.6 1.6 Land portion 2-h 0.6 1.5 Land portion 2-i 0.6 1.5 Land portion 2-j 0.6 1.6 Land part 2-k 0.6 1.5 Land part 2-l 0.5 1.4 Sixth experimental example Land part 2-a 0.4 0.9 Land part 2-b 0.9 0.8 Land part 2-c 0.4 0.9 Land part 2-d 0.5 1.2 Land part 2-e 0.4 1.2 Land part 2-f 0.4 0.8

Each of the golf balls of the first to sixth experimental examples is a wound ball having a balata cover and a liquid center, and has the same structure and composition. The outer diameter is unified to 42.70 ± 0.03 mm, and the compression is unified to 95 ± 2.

[Evaluation of Flying Distance] The golf balls of the first to sixth experimental examples were used with a driver (W1) at a head speed of 45 m / s using a swing robot manufactured by Tsurutemper Corporation. The flight distance test was used. The machine conditions were adjusted so that the spin was 3500 ± 300 rpm and the ball launch angle was 10 ± 0.5 degrees. Table 4 below shows the average of the results of experiments for 20 balls.

[0040]

[Table 2]

In Table 4, the flight distance is from the ball launch point.
It is the distance to the ball resting place. The trajectory height is the elevation angle of the trajectory highest point viewed from the ball launch point.

As shown in Table 4, the golf balls of the first and second experimental examples correspond to the third and fourth experimental examples,
It was confirmed that the golf ball had a longer flight time and a longer flight distance than the golf balls of the fifth experimental example and the sixth experimental example.

This is because dimples disturb the flow of air and improve the aerodynamic characteristics at the positions where the land portions 2 are relatively large enough to form the rectangle 10 and have a smooth shape. Seems to be weakening. In other words, as the location of the land 2 increases, the aerodynamic characteristics of the golf ball during flight decrease.
Conversely, it is considered that the dimple effect is not weakened as the location of the land portion 2 decreases.

[0044]

As is apparent from the above description, in the golf ball of the present invention, the number of lands where a predetermined rectangle can be formed is set to 40 or less, and the area of each land is equal to the dimple average. Because it is so large that new dimples with an area larger than the area can not be formed,
The dimples are extremely dense. Therefore, the dimple effect of disturbing the air flow is not weakened, and the aerodynamic characteristics are improved by the dimple effect, and the flight distance is increased.

[Brief description of the drawings]

FIG. 1 is a front view of a golf ball according to a first experimental example of the present invention.

FIG. 2 is a plan view of a golf ball of a first experimental example.

FIG. 3 is a schematic view showing a relationship between a dimple and a land portion.

FIG. 4

FIG. 5

FIG. 6

FIG. 7

FIG. 8 is a drawing for explaining the specifications of dimples.

FIG. 9 is a front view of a golf ball according to a second experimental example of the present invention.

FIG. 10 is a plan view of a golf ball of a second experimental example.

FIG. 11 is a front view of a golf ball of a third experimental example.

FIG. 12 is a plan view of a golf ball of a third experimental example.

FIG. 13 is a front view of a golf ball of a fourth experimental example.

FIG. 14 is a plan view of a golf ball of a fourth experimental example.

FIG. 15 is a front view of a golf ball of a fifth experimental example.

FIG. 16 is a plan view of a golf ball of a fifth experimental example.

FIG. 17 is a front view of a golf ball of a sixth experimental example.

FIG. 18 is a plan view of a golf ball of a sixth experimental example.

[Description of Signs] 1 Dimple 2 Land 5 Large circle passage 10 Rectangular

Claims (1)

[Claims] 1. A golf ball having dimples and lands other than the dimples on the surface, wherein the short side length is 0.4 mm or more and the area is 0.8 m.
There m ² or more, and a golf ball lands can be formed a rectangular free of some or all of the dimples therein, and equal to or less than 40 places.