JPH01268580A - Golf ball - Google Patents

Abstract

PURPOSE: To provide a golf ball of making possible to reduce an aerodynamic resistance when a ball is flying by composing of that a globe shaped outer surface has a plurality of dimples and the each dimple has the first and second concave portions and these concave portions are adjacent to each other on the circumference of the golf ball. CONSTITUTION: A globular shaped outer surface has a plurality of dimples and each dimple consists of the first and second concave portions and these first and second concave portions are arranged adjacent to each other. The first and second concave portions of the dimples have almost the same size and shape. For example, the dimple 10 having a diameter in range between 2mm and 5mm and a depth in range between 0.1mm and 0.3mm has adjacent two concave portions 11 and 13, and these two concave portions are divided by a dividing portion 12. The dividing portion 12 has a height in range between 0.05mm and 1.3mm. The edge portion of the first concave portion causes the division of a boundary layer and an air stream passing through the second concave portion causes re-joining of the boundary layer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a golf ball with an improved dimple configuration, and more particularly, to a golf ball with a dimple configuration that contributes to reduced aerodynamic drag during pole flight.

FIGS. 1 to 3 are explanatory diagrams explaining the background of the present invention.

Aerodynamic drag (air resistance) occurs on the side opposite the direction of flight. The drag force generated on the pole is influenced by the air flow (boundary layer) close to the pole surface (the first
(see Figures and Figure 1A).

Large drag forces occur when the boundary layer is laminar at the point where it leaves the pole surface (separation point).

To reduce drag, the boundary layer flow should be turbulent at the separation point (see Figure 2), and the final separation point itself should be as far back as possible from the pole (with respect to the direction of flight of the pole). It is necessary to do so. Boundary layer thickness was also found to be important, with increasing boundary layer thickness also increasing aerodynamic drag.

It is an object of the present invention to provide a golf ball whose surface pattern minimizes the thickness of the boundary layer and which causes separation and subsequent reattachment of this boundary layer from the ball surface (FIG. 3). .

Such separation has been found to occur at discontinuities in the outer surface of the golf ball, such as at the edges of dimples or similar recesses.

Accordingly, the present invention has a plurality of dimples on its spherical outer surface, each dimple comprising a first and a second recess, the first and second recesses forming a large circle of the ball. To provide golf balls of the type that are arranged immediately adjacent to each other on the circumference.

Although the present invention is not based on any particular principle or theory, the edges of the first recess cause separation of the boundary layer and the airflow through the second recess causes the rejoining of the boundary layer. I can believe it.

In a first embodiment of the invention, the first and second dimple recesses have substantially the same size and shape.

Additionally, the first dimple recess may be smaller in size and shape than the second recess.

In a second embodiment of the invention, the first dimple recess is formed as an annular body concentric with the second recess, so that the dimple as a whole has the same shape regardless of the direction of movement of the ball. You can do it like this.

Preferably, the dimples are arranged in a uniform regular pattern on the spherical outer surface of the pole.

Next, the present invention will be explained in more detail with reference to FIGS. 4 to 7.

Figures 4 and 5 show a dimple io with an outer diameter ranging from 2 mm to 5 mm and a depth ranging from 0.1 mm to 0.3 mm. The dimple lO has two adjacent recesses 11 and 13, which are separated by a divider 12. Divided part 12
has a height ranging between 0.05 mm and 0.3 mm.

6 and 7 show a dimple lO having a substantially circular second recess 22 and an annular first recess 21 concentric with the second recess. The width of the annular recess 21 ranges between 0.1 mm and 2 mm, and its depth ranges between 0.05 mm and 0.15 mm. The circular recess 22 has a depth ranging between 0.05 mm and 0.3 mm and its diameter ranging between 2 mm and 5 mm. The radial distance between recess 21 and recess 22 is up to approximately 1 mm.

[Brief explanation of the drawing]

1 to 3 are explanatory diagrams of aerodynamic effects for explaining the present invention in detail, FIG. 4 is a plan view showing dimples of the first embodiment of the present invention, and FIG. Line IV-I in the diagram
6 is a plan view showing a dimple according to a second embodiment of the present invention, and FIG. 7 is a sectional view taken along line 1--2 in FIG. 6. (Explanation of main symbols) 10.20: Dimple 11.21: First recess 12: Divided portion 13.22: Second recess. V- μ's Y = current valley i middle iro πi j: Serihi% A・yohi゛ old 5 +, y% +
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Claims (1)

[Claims] 1. In a golf ball having a plurality of dimples on the spherical outer surface, each dimple (10; 20) has a first recess (11; 21) and a second recess (13; 22), wherein the first and second recesses are immediately adjacent to each other on a large circumference of the golf ball. 2. The golf ball of claim 1, wherein the first and second recesses (11, 13) are both substantially the same size and have the same shape. 3. The first recess (21) is the second recess (22)
The golf ball of claim 1, having a smaller size and shape compared to the golf ball. 4. The first recess (21) is the second recess (22)
Claim 1 characterized in that the ring shape is concentric with the ring shape.
, 2 or 3. 5. A golf ball according to claim 1, 2, 3 or 4, characterized in that the dimples (10; 20) are distributed in a uniform regular pattern on the spherical outer surface.