JPH04109968A - Golf ball - Google Patents

Abstract

PURPOSE:To obtain a golf ball which shows stable flying performance by arranging dimples in such a manner that those arranged in a spherical equilateral triangle, and those arranged in adjacent equilateral triangles are in point symmetry with respect to the center point of a short side shared by the triangles, and causing some of dimples to intersect not a first imarginary large circular line but each of three second imaginary large circular lines at their centers. CONSTITUTION:Dimples are uniformly disposed on the surface of a ball 1 and, in this case, those dimples which are arranged in one spherical equilateral triangle I and those arranged in two other spherical equilateral triangles II, IV adjacent the triangle I at the two long sides 4a, 4b of the triangle I, are in line symmetry with respect to the long sides 4a, 4b shared by the triangles I, II, IV. Also, the dimples arranged in the triangle I and those arranged in a spherical equilateral triangle VII adjacent time triangle I, at the short side 5 the equilateral triangle I, are in point symmetry with respect to the middle 6 of the short side 5 shared by both of the triangles I, VII. In addition, to dimple intersects a first imaginary large circular line 2 but at least one dimple intersects each of second imaginary large circular lines 3, 3, 3 at the enter thereof.

Description

Detailed Description of the Invention The present invention improves the dimple arrangement and improves aerodynamic symmetry, thereby exhibiting highly stable flight characteristics and increasing flight distance. Regarding golf balls.

The role of the dimples on a golf ball to help it stretch in the future is to promote the transition of the boundary layer near the surface of the golf ball, which is generated by the movement and rotation of the golf ball, from laminar to turbulent, and to move the separation point backward. The objective is to reduce the pressure resistance by shifting the golf ball to the top and bottom, and to obtain lift from the difference in the separation point between the top and bottom of the golf ball. Therefore, the trajectory of the golf ball changes depending on the shape and arrangement of the dimples, and this trajectory has a large effect on the flight distance of the golf ball.

For this reason, it is desired to develop a dimple shape and arrangement that provides an effective trajectory for increasing flight distance.

On the other hand, golf balls are required to have aerodynamic symmetry as stipulated in the supplementary rule ``Ball (C)'' of the Japan Golf Association Rules. That is, it is required that there be no difference in flight distance or trajectory no matter where on the ball the ball is hit.

Traditionally, commercially available golf balls can be said to have aerodynamic symmetry within the range specified by the above rules, but there are slight differences in flight distance and trajectory depending on the ball's impact position. It is. When using a ball that is aerodynamically asymmetrical, although to a certain extent, this asymmetry can lead to unstable shots, especially at the level of advanced or professional golfers.

The presence of seam lines is one of the causes of aerodynamic asymmetry in golf balls. When manufacturing golf balls, compression molding is performed using two molds with hemispherical molding surfaces, so the dimples formed at the joints of the molds are so large that they do not intersect. It is a circle, and its presence in golf balls is unavoidable due to the manufacturing process.

Here, in the above rule ■ sphere (C), Fig. 6 (A), (
As shown in B), the seam line b of golf ball a
The rotation axis is the straight line e connecting the two mutually opposing points C and C1 above, and the center d./< When ball a is hit 11f to produce spin (Figure A) and the seam line of ball a Hit the ball a so that the axis of rotation is a straight line that is perpendicular to the circular plane g whose circumference is b and passes through the center d of the ball a. It is specified that aerodynamic symmetry is evaluated based on the difference in flight distance, peak angle (the angle of the straight line connecting the highest point of the ball and the point of impact with respect to the horizontal line), and flight time compared to when the ball is hit (Figure B). The hitting method shown in Figure A above is used for ball hitting,
The hitting method shown in Figure B is called seam hitting. When such a ball hitting test is conducted on a golf ball having a seam line as described above, it is known that the trajectory of the ball resulting from hitting the ball has a larger peak angle than the trajectory of the ball hitting the seam.
Because of this, flight distance and flight time also change.

Therefore, it has been proposed to improve the aerodynamic symmetry of the ball by forming a large number of large circles on the surface of the ball with no intersecting dimples, similar to conventional seam lines. For example, the surface of the ball is divided equally into 20 triangles as a regular icosahedron, and the dimples are arranged! ! Various balls with high geometric uniformity have been proposed, such as the w2o-hedron arrangement.

However, even with golf balls having such high geometric uniformity, there is still room for improvement.

The present invention has been made in view of the above circumstances, and by improving the dimple arrangement, golf golfers can improve aerodynamic symmetry, exhibit stable flight characteristics, and exhibit a trajectory that is effective for increasing flight distance. Aim to deliver the ball.

In order to achieve the above object, the present invention provides a means for determining
Draw the first imaginary great circle line of the book, and then draw three second imaginary great circle lines that are orthogonal to the first imaginary great circle line so that the intersection with the first imaginary great circle line is the first imaginary great circle line. The surface of the ball is divided into 6 equal parts, and consists of two long sides with a length of 174, which is the length of a great circle, and one short side with a length of 1/6 of the length of a great circle.
The dimple array in one spherical isosceles triangle is equally divided into spherical isosceles triangles, and the dimple array in one spherical isosceles triangle is divided into two spherical isosceles triangles adjacent to each other with the two long sides of the spherical isosceles triangle as boundaries. It is symmetrical with the dimple arrays in other spherical isosceles triangles that are adjacent to each other with the short sides of the spherical isosceles triangle as the border, and is symmetrical with the dimple arrays in other spherical isosceles triangles that are bordered by the short sides of the spherical isosceles triangle. Point symmetrical across the midpoint of the short side, and no dimples intersect the first imaginary great circle line, and the center of at least one dimple intersects the three second imaginary great circle lines. To provide a golf ball characterized by having dimples arranged as shown in FIG.

Hereinafter, the structure of the golf ball of the present invention will be explained in more detail with reference to the drawings.

In the golf ball of the present invention, as shown in FIG. Circle line 3, 3.3
and the respective great circle lines 2 at six intersections 3a, 3b, 3c
,”・(three not shown) connect this first virtual great circle line 2 to 6
Draw it so that it is equally divided, and draw the surface of this ball 1 with a great circle line 3.
12 spherical isosceles triangles r, n, m... consisting of two long sides 4a, 4b having a length of 1/4 of , and a short side 5 having a length of 176 of the great circle line 2. Xll (XI, X
U is not shown).

Next, dimples are uniformly arranged on the surface of this ball 1. In this case, as illustrated in FIG. Two other spherical isosceles triangles adjacent to each other with their long sides 4a and 4b as boundaries.

■Long sides 4 shared with the dimple arrangement inside
A spherical isosceles triangle ■ which is symmetrical about a and 4b as axes of symmetry and is adjacent to the short side 5 of the isosceles triangle ■.
The dimple arrangement within and both isosceles triangles I and ■ are point symmetrical across the midpoint 6 of the short side 5 that they share, and furthermore, no dimples intersect on the first virtual great circle line 2, and the second Dimples are arranged on each of the virtual great circle lines 3, 3.3 so that at least one dimple intersects each other at the center.

That is, in FIG. 2, dimples Ia, Ib, Ic and semicircular dimples Id, Ie in isosceles triangle 2 are dimples Ila, IIb, IIb in isosceles triangle 2, respectively.
nc and semicircular dimple IId.

The dimple VI a has the same shape as 11e, and is arranged in a line-symmetrical position with the shared long side 4a as the axis of symmetry, and is similarly within the isosceles triangle ■.

VI b, VI'c and semicircular dimple VId,
VIe (VIc is not shown) has the same shape and is located in line-symmetrical positions with the long side 4b as the axis of symmetry. Furthermore,
These dimples Ia, Ib, Ic and semicircular dimples Id, re are dimples ■a within an isosceles triangle ■.

■b, ■C and semicircular dimple ■d, ■e (■a.

(b and d are not shown), and are arranged in point-symmetrical positions with the midpoint 6 of the common short side 5 in between. Also, not a single dimple intersects on the first virtual great circle line 2, while on the second virtual great circle line 3, 3.3 there are dimples (for example, two Equilateral triangle 1. Semicircular dimples Id and I in XI
dimples d) consisting of ld and ld intersect at their centers. Note that the first virtual great circle line 2 where the dimples do not intersect
can be a seam line formed during the manufacture of a golf ball, and there are no dimples that intersect at any point other than the center on the second virtual great circle ls3,3°3.

In addition, here, isosceles triangle ■ is specified as one spherical isosceles triangle, and three isosceles triangles adjacent to this triangle ■
As described above, the relationship between .

Furthermore, although the golf ball described above has only a very small number of dimples for convenience of explanation, it actually has many more dimples. Specifically, although not particularly limited, 360 to 460 dimples, particularly 390 to 440 dimples are suitably arranged.

Furthermore, although the number of types of dimples can be one or more, it is particularly preferable to arrange three types of dimples having different diameters and depths uniformly on the ball surface. At this time, there are no particular limitations, but the maximum dimple is 3.9 to 4.2+fffi in diameter and 0.17 to 0.21 m in depth.
The middle dimple is 3.3 to 3.7 II in diameter! +,
It is preferable that the depth is 0.15 to 0.19 mm, and the minimum dimple is 2.4 to 3.2 mm in diameter and 0.08 to 0.15 mm in depth.

Also, when arranging multiple types of dimples like this,
The number of dimple types is n, the diameter of each dimple is
When the depth is Dpk and the number is Nk (where k
=1.2.3...n), the following formula (1) (In the formula, R is the ball radius, Vo is the dimple space volume under the plane surrounded by the edge of the dimple, with the plane above as the bottom surface, The value obtained by dividing the maximum depth of the dimple from the bottom by the volume of the cylinder whose height is
63674), and Nk is the number of dimples. ) Dimple total surface area index iI! A(D
By setting st) to 4 or more, a more excellent effect of increasing flight distance and improving aerodynamic symmetry is exhibited.

Furthermore, the average of all dimples is 0.0, which is the value vO obtained by dividing the volume of the dimple space under the plane surrounded by the edges of the dimple by the volume of a cylinder whose height is the maximum depth of the dimple from the bottom plane. 4-0.52, especially 0
．． It is preferable that it is 45-0.5.

Specific examples of the dimple arrangement of the golf ball of the present invention include the arrangements shown in FIGS. 3 and 4. That is, the diameter in FIG. 3 is 4.05 mm.

Depth 0.18m + 1' Vo value is Q, 47 (7) maximum depup) I, t 204 pieces, diameter 3.50mm, depth 0.
168 medium dimples with a Vo value of 0.47 at 17mm,
Diameter 2.50mm, depth 0.12ne, Vo value 0.4
This is an example in which 48 minimum dimples of 7 are arranged according to the present invention, and Dst is 4.43. Also, Fig. 3 shows a diameter of 4. OOm+, Vo value is 0.4 at depth 0.19mm
7 maximum dimples 144, diameter 3.60m, depth 0
．． 216 medium dimples with a Vo value of 0.47 at 18 mm, a diameter of 2.45 mm, a depth of 0.13 mm and a Vo value of 0.4
In this example, 60 minimum dimples of 7 are arranged according to the present invention, and Dst is 4.24.

The golf ball of the present invention may be a solid golf ball such as a one-piece ball or a two-piece ball, or a wound golf ball, and the manufacturing method thereof may be a conventional method.

Function The golf ball of the present invention has the dimple arrangement described above, which improves aerodynamic symmetry and makes it possible to compensate for differences in flight distance and trajectory caused by differences in the ball's impact location, that is, the axis of rotation of backspin. Therefore, it exhibits stable flight characteristics at all times and a trajectory that is effective in increasing flight distance.

As explained above, the golf ball of the present invention has improved aerodynamic symmetry due to the improved arrangement of dimples, exhibits stable flight characteristics, and increases flight distance. It shows an effective trajectory and provides a good flight distance.

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples and Comparative Examples, but the present invention is not limited to the Examples below.

[Example, comparative example]

Three types of two-piece golf balls having dimples having the properties shown in Table 1 were manufactured. All configurations were the same except for the properties of the dimples.

Table 1 The flight characteristics of these golf balls were investigated by conducting the following tests.

True Tem for each ball
Using a striking robot manufactured by Per), pole strikes and seam strikes were performed 24 times each at a head speed of 45 m/sec. The apparent height was measured, and the average value of 24 measurements was taken as the final measured value. We evaluated the symmetry of each ball for each measurement item and considered its flight characteristics. The respective measured values are shown in Table 2.

As can be seen from the results shown in Table 2, the golf balls of the comparative example do not necessarily have bad symmetry in carry, but the symmetry in total distance is poor in the golf balls of the present invention (Example 1 and It is significantly inferior to 2). This is also reflected in the difference in peak angle, as the peak angle of the trajectory of the golf ball hit in this comparative example is high, and in this case, the momentum of the ball during and after the fall is small, resulting in a poor run. This is due to the fact that there are few. This means that the flight characteristics (trajectory, etc.) due to the dimple arrangement are poor, which reduces flight distance. In other words, the difference in trajectory between seam hitting and pole hitting means that sometimes the flight distance is long and other times the flight distance is short, which reduces the absolute flight distance of the ball. become. Moreover, such a ball has poor flight stability and is difficult to handle.

In contrast, the golf balls of the present invention (Examples 1 and 2)
It has been recognized that it has excellent aerodynamic symmetry, exhibits stable flight characteristics, and exhibits a trajectory that is effective in increasing flight distance.

[Brief explanation of drawings]

1 and 2 are explanatory diagrams explaining the dimple arrangement of the golf ball of the present invention, FIGS. 3 and 4 are plan views respectively showing examples of the present invention, and FIG. 5 is a comparative example of a golf ball. The plan view of the ball, FIGS. 6(A) and 6(B), are explanatory diagrams illustrating the method for evaluating aerodynamic symmetry. 1...Golf ball 3.3.3...Second imaginary great circle line 5...Short side ■-ho...Spherical isosceles triangle 2...First imaginary great circle line 4a, 4b...・Long side 6...Middle point

Claims (1)

[Claims] 1. Draw one first imaginary great circle line on the ball surface, and then draw three second imaginary great circle lines perpendicular to the first imaginary great circle line so that the intersection with the first imaginary great circle line is this. Draw the first imaginary great circle line into six equal parts, and divide the ball surface into two long sides with a length of 1/4 of the length of the great circle and one with a length of 1/6 of the length of the great circle. The short sides of the book are equally divided into 12 spherical isosceles triangles, and on the surface of this ball, the dimple array within one spherical isosceles triangle is adjacent to the two long sides of the spherical isosceles triangle. It is symmetrical with the dimple arrangement in two other spherical isosceles triangles, with the long sides that they share as the axis of symmetry, and in the other spherical isosceles triangles that are adjacent to each other with the short sides of the spherical isosceles triangles as the border. The dimple arrangement is point symmetrical across the midpoint of the short side that they share, and is
A golf ball characterized in that dimples are arranged so that the dimples do not intersect on the imaginary great circle lines and the center of at least one dimple intersects on the three second imaginary great circle lines.