JP2865632B2 - Golf ball - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a golf ball, and more particularly, to a golf ball having improved dimples. 2. Description of the Related Art Conventionally, various techniques have been proposed or implemented with respect to the pattern and shape of golf ball dimples mainly for the purpose of improving the flight performance of golf balls. [0003] The prior art is roughly divided into those which attempt to optimize individual shapes of dimples (diameter, depth, cross-sectional shape, etc. of uniform dimples) (Japanese Patent Application Laid-Open No. 60-962).
No. 72, Japanese Patent Application Laid-Open No. 60-163677, Japanese Patent Application Laid-Open No. 58-2
No. 5180, JP-A-49-52029, etc., in which the pitch between dimples is specified within a certain range (Japanese Patent Publication No. 58-1982).
No. 50744, JP-A-53-115330), a mode in which all dimples are arranged at equal pitches (JP-A-57-107170), a portion without dimples is evenly arranged on a ball spherical surface. What you are doing
No. 7-22595) and the like. [0004] However, a point common to the above-mentioned prior arts is that "the individual dimple shapes are exactly the same". In the first place, golf balls are used in golf competitions.
High speed of up to 80 m / sec and 2000 to 10000
This is because it has conventionally been considered that the sphere flying at a high rotation speed of rpm affects the aerodynamic force on the ball sphere as an average dimension. On the other hand, the role of dimples in a golf ball is to promote the transition of turbulence in the boundary layer and cause turbulent separation, so that the separation point is more rearward than in laminar flow separation of a golf ball without dimples. The point is that the pressure resistance is reduced by reducing the separation area, and the point that the lift is improved by promoting the vertical difference between the separation points. And this must be effective for all rounds from low speed to high speed. However, when dimples of the same shape are arranged on the ball sphere as in the prior art, the effect is maximized at the flight speed at which the dimple of the shape works most effectively. In the speed range, it did not work effectively and there was a problem in overall performance. [0007] On the other hand, the relationship between the surface roughness of a sphere and the drag has been studied for a long time. If the surface roughness becomes rougher than the drag of a smooth sphere, the drag at the critical Reynolds number and the region beyond the drag are considered. And the critical Reynolds number tends to decrease. In the case of the golf ball dimples, the resistance is mildly increased in a region exceeding the critical Reynolds number, unlike the surface scratching roughness, but the same can be said for the above tendency. [0008] The critical Reynolds number of the smooth sphere is much larger than the actual use range of the golf ball. As the surface roughness increases, the low-speed range shifts to the actual use range of the golf ball. However, in a golf ball, for example, when the dimple diameter is increased, the critical Reynolds number decreases, and the drag in a low speed range tends to decrease, and the drag in a high speed range tends to increase. The same applies when the number of dimples is increased or when the dimple depth is increased to some extent. Conversely, reduce the dimple diameter,
When the number of dimples is reduced or the depth of the dimples is reduced to some extent, the critical Reynolds number increases, and the drag in the low speed range tends to increase and the drag in the high speed range tends to decrease. Therefore, in the prior art, there is no dimple capable of exerting the maximum effect in the entire region from the high speed immediately after the flight to the flight peak and the low speed from the flight peak to the fall, and various studies have been made on the dimple arrangement and the like. But there was a limit. In other words, when the number of dimples is small or the dimple diameter is small, it becomes a good ball with good elongation immediately after flying, but a so-called hop phenomenon occurs near the flight peak, it rises and falls at an obtuse angle, and the flight distance in the latter half of the flight Loss occurs. On the other hand, in the opposite case, the ball is stretched without a hop near the flight peak and falls at a relatively acute angle. However, the flight immediately after the flight is insignificant and a flight distance loss occurs in the first half of the flight. Although there is a problem of lift along with these drag conditions, in a high-speed region above the transition region, when the number of dimples is large, when the dimple diameter is large, or when the dimple depth is somewhat deep, generally, It has low lift and is disadvantageous in terms of flight distance, but is advantageous in that it is not affected by wind. On the other hand, if only the dimple arrangement pattern itself is extracted, it is necessary to make it as non-directional as possible, and various proposals have been made so far. That is, the first type having approximately 336 dimples arranged in a regular octahedron is disclosed in
One with 416 dimples found in 11665. Secondly, those having 360 dimples arranged in a regular dodecahedron as shown in JP-B-57-22595. Third, JP-A-49-52029 and JP-A-60-210
252 arranged in icosahedron as seen in -23467
One having four dimples, one having 432 dimples, and one having 492 dimples.
Fourthly, a dimple having about 332 pieces by removing one line of the seam portion from the icosahedral arrangement shown in JP-B-58-50744 or increasing the number of lines by about 392 due to the circumstances of mold making. Fifth, JP-A-53
Approximately 28 concentrically arranged as seen in -115330
One having 0 to 350 dimples. Sixth, there are those having 320 dimples arranged in a regular icosahedral arrangement and at an equal pitch in Japanese Patent Application Laid-Open No. 57-107170. The fourth and fifth arrangement patterns are as follows:
The directionality of the arrangement is tight, and the trajectory differs depending on the rotation axis when the golf ball is shot. Therefore, it is out of the question in the sense of non-direction. The other arrangement is considered to be a good arrangement in the sense of non-direction. Therefore, the present invention solves such a conventional problem and can minimize the drag and optimize the lift in the actual use range of the golf ball from the high speed range to the low speed range. It is an object of the present invention to provide a golf ball that can be formed. In the golf ball of the present invention, a plurality of types of dimples having different diameters are arranged on a ball spherical surface, and a great circle band not including a part of each dimple is formed. is 0-1 formed, and a land portion surrounded by said dimples, formed to a size that can not be a new dimple is formed having an average area or more area of the dimples, and further, about 1 up to dimple diameter /1.3
The minimum number of dimples having a diameter of
13% or more and 29% or less . Embodiments of the present invention will be described below in detail with reference to the drawings. FIGS. 1 to 6 specifically show different embodiments of the present invention. In any of the embodiments, four types of large and small dimples 1, 2, 3, and 4 are arranged on a ball spherical surface, and a land portion 5 surrounded by the dimples 1, 2, 3, and 4 is provided. Are formed in such a size that a new dimple having an area larger than the average area of the dimples 1, 2, 3, 4 cannot be formed. In other words, this land part 5 ...
Means that a circle larger than the average dimple area circumscribing each dimple 1, 2, 3, 4 cannot be drawn. Although the type of dimples can be freely increased or decreased, when considering the trajectory of a golf ball, the flight curve of the ball is divided into four parts, and four types of dimples having different dimple effects are combined in accordance with each area. Is most desirable. For example, if the golf ball has a ball flight speed of 6
When hit at a speed of 5 m / sec and a backspin of 3500 rpm, the ball speed is from 65 m / sec to about 50 m / sec.
An initial trajectory of about 20 seconds, a second trajectory having a ball velocity of about 50 m / sec to about 35 m / sec, and a ball velocity of about 35 m / sec.
It is divided into a third trajectory from second to about 25 m / sec and including the highest point of the trajectory, and a fourth trajectory from the second to the landing where the ball speed is about 25 m / sec. In this case, the flight time of the initial trajectory and the second trajectory area are each about 1 second, and the third trajectory and the fourth trajectory are each about 2 seconds. Although there are various methods of division, the following design is performed to maximize the dimple effect according to the method. In the case of the above example, the flight speed V in four regions
1, V2, V3, V4 are respectively 65 m / sec, 50 m / sec,
35 m / sec and 25 m / sec, and the volumes v1, v2, v3, v
When the 4, V1: V2: V3: V4 = v4 2: v
^{3 2: v2 2: v1 2} = 65: 50: 35: preferably designed as 25. In this case, v4 / v1 is about 1.
6, but good results are obtained in the range of 1.5 to 2.0. In other words, for the dimple effect, the flight speed at which the utility is desired to be extracted, the square of the dimple volume,
For best results. With respect to the arrangement ratio of the dimples having different dimple effects, it is desirable to increase the ratio of the dimples for which the utility is desired to be exerted in the important region, depending on which region of the divided region is to be emphasized. It is desirable that the number of dimples is 10% or more of the total number of dimples. For example, the number of dimples of four types is N
When N1, N2, N3, and N4 are used, and the third trajectory is most important, and then the fourth trajectory is important, N1: N2: N
3: N4 ≒ 1: 1: 3: 2 is preferable, and when the fourth trajectory is most important, N1: N2: N3: N4 ≒ 1: 1:
It is good to set to 1: 2. In determining the arrangement ratio, consideration should be given to the balance with the total number of dimples, and the smaller the total number of dimples, the greater the importance of the fourth and third trajectories. For example, N1: N2: N3: N4 and the total number of dimples is 30
When the number of dimples is from 0 to 350, the ratio is about 1: 1: 1: 2, and when the number of dimples is 351 to 400, the ratio is about 1: 1: 2: 2.
When the total number of dimples is 401 to 450, about 1: 1:
3: 2, and when the total number of dimples is 451 to 500,
Preferably it is about 1: 2: 4: 1. In the present invention, the diameter of the largest dimple is about 1 / 1.3 of the diameter E (see FIG. 11).
The number of small dimples is 13% or more and 29% of the total number of dimples
Ru is the following. In Table 1 below, the diameter of about 1 / 1.3 is
The smallest dimple has the largest size. That is, in Table 1 described later, Emax / Emin is 1.3 (value indicated by rounding), and " about 1 / 1.3 of the diameter of the largest dimple" in the present invention means (rounding). (Indicated by) is the reciprocal of the above 1.3. In Table 1, " approximately "
The smallest dimple with a diameter of 1 / 1.3, ie
As is clear from the table, the ratio (percentage) of “the fourth largest dimple” to the total dimple is 19 in Example 1.
%, 19% in Example 2, 29% in Example 3, 14% in Example 4, 13% in Example 5, and 27% in Example 6.
%. The following can be said from the results. That is, the minimum having a diameter of about 1 / 1.3 of the diameter of the largest dimple
The ratio of dimples to total dimples is 13
% , The good results (carry, total, etc.) shown in Table 1 cannot be obtained. Conversely, if it exceeds 29% , the number of dimples having a small diameter becomes too large, and the effect of disposing “a plurality of types of dimples having different diameters” cannot be achieved. The relationship between volume, diameter, and depth is a spherical difference dimple. In the case of a dimple having a spherical shape, the volume is proportional to the product of the square of the diameter and the depth. As shown in FIG. 10, the apparent radius Ra of the dimple spherical surface 7 in the range A between the portion lowered by 30 μm and the portion lowered by 90 μm from the dimple edge 6 in the depth direction is determined by the diameter E of the dimple and the depth. n
(Here, the diameter of the dimple is, as shown in FIG. 11,
The dimension is between the dimple edges 6 and 6, and the depth is a dimension from the ball phantom spherical surface 8 to the lowest dimple portion 9. 70) of the dimple spherical radius Ro derived from
If the dimple wall surface is set to 90%, the inclination of the dimple wall 10 is made sharp, and the dimple volume is set to be proportional to the product of the diameter E and the depth n, more stable results can be obtained. At this time, if the diameter E × depth n is C (in each of the dimples 1, 2, 3, and 4, C1, C
2, C3, C4), the above-mentioned v4 / v1 is C4 /
It is approximated to C1. That is, the preferable range of C4 / C1 (the ratio of the product of the diameter E and the depth n) is 1.5 to 2.0. Further, as the diameter E of the dimples increases, the depth n of the dimples is increased, and the ratio of the diameter E and the ratio of the depth n of each dimple is 1.2 to 1.5, respectively. Is desirable. Finally, regarding the dimple arrangement, in addition to the non-directionality, the great circle band 11 that does not include a part of each dimple over the entire sphere (that is, the sphere is set so as to include the center of the sphere) In the case of cutting, reducing the outer peripheral surface of the cut surface as much as possible will stabilize the peeling point. Therefore, in principle, the great circle band is 0, but one great circle band 11 is formed in FIGS. This is for facilitating mold splitting when forming a golf ball. In the present invention, the number of dimples is desirably in the range of 240 to 560, and particularly desirably 300 to 450. Also, in any of the cases of FIGS. 1 to 6, the α value defined by the equation 1 is set so as to be in the range of 500 to 1000. This α value is “a dimple effective volume index per unit surface area of the ball”. ## EQU1 ## Next, an experiment for confirming the effect of the embodiment of the present invention was conducted. [0034] True Temper (USA)
USGA (United)
States Golf Association)
ODS (Overall Distance star)
ndard), a flight test was performed at the No. 1 wood club at a head speed of 45 m / sec, and the difference between the flight carry and the total distance was evaluated. (This condition is almost the ball initial speed 65m /
This is the condition to meet in seconds. ) In addition, each measurement is 20
Evaluate with the average value for each. Tables 1 and 2 list the types of balls used in each experiment and the results of the experiments. [Table 1] [Table 2] In Tables 1 and 2, the calculation of the surface area occupancy indicated by ** is performed as follows. [Calculation method] Equation ｛π (4.3 / 2) ² × 132 + π (3.9 / 2) ² × 60 + π (3.6 / 2) ² × 60 + π (3.3) in the case of the first embodiment / 2) ² × 60 ° / {4π (42.67 / 2) ² } (The diameter of the golf ball (large size) is a specified value of 1.68 inch = 42.67 mm.) Details of Examples 1 to 6 in the table are shown below. Examples 1 to 6 Large two-piece balls having a structure described in JP-A-59-5
According to Example 1 of No. 7657. It has the specifications shown in Tables 1 and 2. Example 1: dimple arrangement pattern of FIG. 1 Example 2: dimple arrangement pattern of FIG. 2 Example 3: dimple arrangement pattern of FIG. 3 Example 4: dimple arrangement pattern of FIG. 4 Example 5: dimple arrangement pattern of FIG. Embodiment 6: Dimple arrangement pattern of FIG. 6 In all of Embodiments 1 to 6, the case where only one great circle band is used is shown. The frontage depth B in parentheses below the dimple depth is a height dimension from the dimple minimum portion 9 to the dimple edge 6, as shown in FIG. Further, the wall surface curvature ratio is defined as the diameter E and the depth n.
The dimple spherical radius Ro derived from the dimple edge 6 and the wall surface 10 in the range A between the part lowered by 30 microns and the part lowered by 90 microns in the depth direction from the dimple edge 6 are centered on a straight line connecting the dimple center and the ball center. The apparent spherical radius R obtained by the true sphere equivalent least square method
a = (Ra / Ro) × 100%,
The smaller the value, the steeper the dimple inclination angle. Examples 1 to 6 are all polyhedral,
It is a dihedral arrangement. Next, Table 3 shows a list of types of balls of Comparative Examples 1 to 3 and experimental results. [Table 3] Here, details of Comparative Examples 1 to 3 in the table are shown below. Comparative Example 1 A conventional octahedral arrangement having 336 dimples and the same structure as in Examples 1 to 6,
And it has the specifications shown in Table 3. And it is a dimple arrangement pattern shown in FIG. Comparative Example 2 In addition to having 392 dimples in an icosahedral arrangement found in the experimental example of JP-B-58-50744, the structure was the same as in Examples 1 to 6, and the specifications shown in Table 3 Has. And it is a dimple arrangement pattern shown in FIG. COMPARATIVE EXAMPLE 3 A icosahedral array having 432 dimples as disclosed in Japanese Patent Application Laid-Open No.
6 and has the specifications shown in Table 3. And it is a dimple arrangement pattern shown in FIG. Thus, comparing Examples 1 to 6 with Comparative Examples 1 to 3, Examples 1 to 6 are superior to the comparative example in terms of carry by 2 to 9 m and total by 3 to 15 m. The effect on up was confirmed. As described above, a combination of a plurality of dimples having different shapes (especially, four types of combinations from a large deep dimple to a small and shallow dimple) can realize a flight performance not available in the prior art. The present invention is not limited to the above-described embodiment, and the design can be freely changed without departing from the gist of the present invention. For example, the present invention is not limited to a two-piece ball, but may be a wound ball,
It can be applied to multi-layer and single-layer solid balls as well as small size. Further, the present invention is applicable to a dodecahedron as a basic pattern, an octahedron, an icosahedron, and the like. With the above-described structure, a plurality of types of dimples are provided instead of uniformly and uniformly arranged over the entire spherical surface of the ball. Unlike the situation where the dimples are neatly aligned around, the air flow is more disturbed, the separation point is lowered backward, and the dimples of each dimple shape work effectively in each speed region during ball flight I do. That is, in the high-speed region, dimples having a small dimple effect exhibit utility, and in the low-speed region, dimples having a large dimple effect exhibit utility. Here, the large dimple effect means that dimple 1
It means that the volume per unit is large, and it can be increased by increasing the dimple diameter, increasing the dimple depth, sharpening the dimple wall surface inclination, or a combination thereof. Further, a small dimple effect means that the volume per dimple is small. Further, by forming the land portion surrounded by the dimple to a size in which a new dimple having an area larger than the average area of the dimple cannot be formed, the ratio of the area of the dimple to the spherical surface of the golf ball (surface area) Occupancy), and the airflow is more disturbed than a golf ball with a large proportion of land,
The peel point can be lowered backward. Since the present invention is configured as described above, the following effects can be obtained. In the golf ball of the present invention, unlike any state in which the dimples are neatly aligned around any rotation axis on the ball spherical surface, the air flow is more disturbed,
The peeling point is lowered rearward, and the dimples of the respective dimple shapes effectively act in the respective velocity regions during the flight of the ball. In other words, a dimple having a small dimple effect exerts an effect in a high-speed region, and a dimple having a large dimple effect exerts an effect in a low-speed region. Therefore, it was possible to optimize the lift and effect from high speed to low speed range during the flight of the ball, thereby producing an effect of increasing the flight distance. The trajectory of the conventional dimple ball was improved. There is no "hop" that occurs when attempting to extend the carry, and a stretchy straight sphere can easily provide a wind resistant ball. In a golf ball having a single type of dimple, the number of dimples is usually about 330 to 390. If the number of dimples is designed to be small, the flight distance may be reduced due to lifting in the latter half of the flight. If the number of dimples is designed to be large, the flying distance is reduced due to the large effect and the small lift in the first half of the flight. However, even if the number of dimples is reduced, the golf ball of the present invention does not have a reduced flight distance due to an increase in the effect due to an increase in the wake area due to the advance of the lower separation point generated in the low-speed region in the single type dimple. Even if the number of dimples is increased, a stable flight distance can be obtained without a decrease in flight distance caused by an increase in wake area due to advancing of an upper separation point generated in a high-speed region in a single-type dimple. The diameter of the largest dimple is about 1 /
By setting the ratio of the minimum number of dimples having a diameter of 1.3 to the total number of dimples to be 13% or more and 29% or less , good results (see Tables 1 and 2 ) can be obtained for carry, total, and the like. In addition, the effect (described above) of disposing a plurality of types of dimples can be sufficiently exhibited.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a dimple arrangement pattern diagram for explaining a first embodiment of the present invention. FIG. 2 is a dimple arrangement pattern diagram for explaining a second embodiment of the present invention. FIG. 3 is a dimple arrangement pattern diagram for explaining a third embodiment of the present invention. FIG. 4 is a dimple arrangement pattern diagram for explaining a fourth embodiment of the present invention. FIG. 5 is a dimple arrangement pattern diagram for explaining a fifth embodiment of the present invention. FIG. 6 is a dimple arrangement pattern diagram for explaining a sixth embodiment of the present invention. FIG. 7 is a dimple arrangement pattern diagram showing a comparative example. FIG. 8 is a dimple arrangement pattern diagram showing another comparative example. FIG. 9 is a dimple arrangement pattern diagram showing another comparative example. FIG. 10 is an enlarged sectional view of a main part. FIG. 11 is an explanatory diagram showing a relationship between a diameter and a depth of a dimple. [Description of Signs] 1 Dimple 2 Dimple 3 Dimple 4 Dimple 5 Land 11 Great circle

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Claims (1)

(57) [Claims] A plurality of types of dimples having different diameters are arranged on the ball spherical surface, and 0 to 1 great circle band not including a part of each dimple is formed, and a land portion surrounded by the dimple is The dimple is formed to a size that cannot form a new dimple having an area equal to or larger than the average area of the dimple, and further, about 1 / 1.3 of the diameter of the largest dimple.
The minimum number of dimples having a diameter of
A golf ball characterized by being 13% or more and 29% or less .