Patent Application
20210402261
This application is based on and claims priority under 35 U.S.C. §119 to Korean Patent Application No. 10-2020-0080505, filed on Jun. 30, 2020, in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety.
The present disclosure relates to a golf ball, the golf ball having a reduced resistance during flight and an increased flying distance by forming a new type of dimple different from dimple shapes that are commonly used.
In a golf ball, dimples have very important aerodynamic functions. Circular dimples or polygonal dimples symmetrically arranged are formed on surfaces of general golf balls. When the golf ball is struck by a golf club head, a rebound resilience of the golf ball is induced and the golf ball bounces out at a high speed, and at the same time, a reverse rotation occurs due to a loft angle of the club head. In a golf ball flying in reverse rotation, air pressure accumulates in the lower part under the influence of dimples, and the pressure decreases rapidly in the upper part, thereby generating a lift that is several times the gravity, which gradually rises and increases the flying distance by increasing the flying time.
In this case, under the influence of the dimples, an air flow causes turbulence and moves a separation point of a boundary layer to a rear portion of the golf ball and then reduces a drag coefficient due to the rapid air flow, and therefore, resistance during flight is reduced and the flying distance increases.
A flight trajectory indicating a flying trace is as important as the flying distance. The flight trajectory is important as it indicates a flying distance to a flying peak after the shot is taken, a degree of straightness in which a flying direction inclines to the left or right or is straight in a proceeding direction, a landing point of the golf ball according to the degree of straightness, a falling angle and a falling distance to the ground after the peak, and the like. In addition, the flight performance to overcome wind influences such as headwind, tailwind, and crosswind is one of the important factors of dimples.
The flight performance that is aerodynamically important is determined according to shapes or sizes of the dimples, roughness indicating how rough the dimples are, a proportion of an area and a volume to an area and a depth of the dimple, and the like.
That is, although basic factors of the flight performance are determined according to differences in speed of the club head, and weight, size, hardness, and rebound resilience capacity of the golf ball, the flight performance of the golf ball is significantly influenced by the dimples that are already formed.
In the case of circular dimples that are most commonly used in golf balls, a golf ball including dimples with a large diameter and similar dimple depths easily gains a lift after the shot and obtains a trace of a high trajectory, wherein a drag coefficient in a high-speed region to the peak is large but the drag coefficient in a low-speed region after the peak rather decreases. However, due to being highly influenced by the wind, the flying distance increases in the tailwind, but the landing point is not constant in the headwind or crosswind, and therefore, there is a problem with directionality. On the contrary, in the case of a golf ball including dimples that have a small diameter, as it is difficult to obtain the lift after the shot, the golf ball has a trace of a low trajectory, and a drag coefficient decreases compared to that of a large-sized dimple in a high-speed region but increases in a low-speed region. However, unlike with large-sized dimples, the golf ball is less influenced by the wind and the directionality thereof does not deteriorate.
Comparing the case of simply varying the depth of the dimple in a golf ball of the same diameter, it becomes easier to obtain lift when the depth gets deeper, but in the high-speed region, the pressure drag increases rapidly, reducing the flying distance, and if the depth is too deep, the influence of the wind is greatly affected. On the contrary, if the depth becomes too shallow, the total dimple volume becomes small, so that sufficient lift cannot be obtained and the distance is reduced. In a golf ball including circular dimples, the dimples are arranged by dividing a surface of a sphere into a virtual spherical polyhedron in a symmetrical manner. However, even with an effort to minimize a portion without dimples, that is, a land portion, it is difficult to make an area ratio of the land portion, that is, a dimple area ratio, 82% to 83% or more with reference to a total surface area of the sphere. When a total dimple area of a golf ball having a dimple area ratio from 82% to 83% and an appropriate depth calculated according to a frustum depth is from 390 mm3 to 420 mm3, a result with an excellent flight performance is obtained.
In a golf ball including polygonal dimples, bottom surfaces at a dimple depth generally have a circular or oval shape, and under the influence of the shape of bottom surfaces, general flight performances are similar to those of circular dimples. However, the bottom surfaces with a deeper depth are highly influenced by wind and have poor straightness, and therefore, a landing point is not constant. However, the bottom surfaces with a shallow depth have a low trajectory and are less influenced by wind, being more stable than the bottom surfaces with a deeper depth, but the flying distance is decreased. The golf ball including the polygonal dimples caused a turbulent transition faster than that of the golf ball including the circular dimples, but the pressure drag also rapidly increased, and therefore, the flying distance is not increased.
Despite these shortcomings, the polygonal dimples may form a rapid turbulent transition, and according to arrangements of the dimples, the land portion having a direct influence on the flying distance may be minimized, and thus, great progress may be made.
U.S. Pat. No. 6,290,615 B1 describes a case in which a golf ball has polygonal dimples and a peripheral region around a peak of a protrusion region between the dimples, such that a drag is more reduced than in a case where general dimples are merely dug in a round shape in the sphere and a portion at which the dimples meet are angled.
U.S. Pat. No. 6,315,686 B1 describes a case in which spherical concave surfaces around the polygon are overlapped and the polygon has a ridge-like polygon shape and easily forms a turbulent boundary layer, and may achieve a high speed without interference even in a low-speed region.
U.S. Pat. No. 7,686,709 B2 describes a dimple in which lobes having ridges are connected like spokes around a center of a dimple and a connected portion between lobes becomes a concave portion.
In U.S. Pat. No. 5,143,377, in a case where dimples are arranged at about fifteen degrees around a large circle of a sphere as an L-spherical region and other portions as an F-spherical region, dimples having a regular polygon shape are arranged in 60% or more of the L-spherical region, and circular dimples are arranged in 60% or more of the F-spherical region.
U.S. Pat. No. 5,536,013 discloses a case in which a center portion of a cross-section of a dimple is concave and a portion surrounding the center portion is pushed down to a depth of a regular dimple, and a shape of the dimple is circular or polygonal.
U.S. Pat. No. 6,290,615 B1
U.S. Pat. No. 6,315,686 B1
U.S. Pat. No. 7,686,709 B2
U.S. Pat. No. 5,143,377
U.S. Pat. No. 5,536,013
To overcome the shortcomings in the related art, the present disclosure provides a golf ball having an extraordinary flight performance that may combine a high turbulence transition capacity of polygonal dimples with the flying tenacity and flying stability of circular dimples.
Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments of the disclosure.
The present disclosure relates to a golf ball, wherein, when a plurality of dimples are arranged on a surface of the golf ball, the dimples have a shape of a combination dimple in which a depth is given to a surface that is made by combination of a circle ci and a polygon po having a same center, and the combination dimples co are arranged on the entire surface of the golf ball, or 50% or more of the surface is arranged with the combination dimples co and the rest is arranged with general circular dimples. Although the polygons po and the circle ci included in the combination dimple co are concentric, a diameter d of the circle ci is greater than an inscribed circle di of the polygon po and smaller than a circumscribed circle dc of the polygon po. That is, in the relationship of dc<d<di, the circle ci included in the combination dimple co has one diameter but is combined with the polygon co, and therefore, in a face that is shown, according to polygon types, only arc faces of an identical number as that of edges of the polygon po are shown. Accordingly, when the polygon is a pentagon, five arcs having an equal radius are shown, and when the polygon is a hexagon, six arc faces having an equal radius are shown.
In the edges of the polygon po included in the combination dimple co, portions overlapping with the arc faces that are generated by dividing the circle ci are invisible, and only each vertex and a fragment portion of a portion of an edge connected thereto (hereinafter, referred to as a vertex region vr) are visible. Accordingly, when the polygon is a pentagon, five vertices yr having same shape and size are shown, and when the polygon is a hexagon, six vertices yr having same shape and size are shown. The vertex region vr, which is a small bluff body sb being important portion of the present disclosure, reduces a drag by dispersing in advance a pressure applied to the entire dimples of the golf ball, and the flying distance increases. Due to the arc faces being widen instead of being removed, the edges of the polygon po may reduce the problem of directionality shown in golf balls including general polygonal dimples.
The above and other aspects, features, and advantages of certain embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:
Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the embodiments are merely described below, by referring to the figures, to explain aspects of the present description. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.
The present disclosure relates to a dimple having an extraordinary flight performance by combining advantages circular dimples and polygonal dimples in the related art, that is, a combination dimple having extraordinary flight straightness and being capable of increasing a flight distance by causing a rapid turbulent transition and decreasing a drag, wherein the combination dimples in which a depth is given to a surfaces having a combined shape of a polygon and a circle being concentric on a surface of a sphere, and bending of a trajectory under high influence by the wind, which is a shortcoming of the polygonal dimples in the related art, is eliminated.
A golf ball according to embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.
As shown in
In the case of combination dimple co in which a depth is given to a face having a combined shape made by a square and a circle among the combination dimples shown in
In the case of a combination dimple co in which a depth is given to a face having a combined shape made by a pentagon and a circle among the combination dimples shown in
When a depth is given to a face having a combined shape made by a hexagon and a circle among the combination dimples co, an appropriate diameter d of the circle included in the combination dimple co is from 88% to 94% of the diameter dc of a circumscribed circle of the hexagon. Accordingly, the small bluff body sb in the combination dimple co in which the depth is given to the face having the combined shape of the hexagon and the circle is from 6% to 12% of a radius of the circumscribed circle of the hexagon.
Among the combination dimples in
Like this, the size of the small bluff body sb gradually decreases as the number of vertices of the polygon increases. In other words, as the number of vertices of the polygon increases, a shape thereof becomes close to a circle, the size of the small bluff body sb decreases, and functions thereof also decrease. Accordingly, a combination dimple in which a depth is given to a face having a combined nonagon or more shape of polygon and a circle has a similar flight performance without difference as that of a general circular dimple.
As shown in
The depths hp and hc may be an identical depth or different depths. A depth of a dimple varies according to a size of the dimple. However, when the depth is 0.25 mm or deeper, wind resistance increases and causes lack of flight stability, and when the depth decreases to 0.1 mm or more shallow, it is hard to obtain a lift and a flying distance decreases. Therefore, it is preferable that the depth of the combination dimple is from 0.1 mm to 0.25 mm based on the frustum depth.
In an embodiment shown in
In the embodiment shown in
In a golf ball 77, general circular dimples are arranged near each vertex and at a center of the spherical square in the spherical cube-octahedron. The arrangement of general circular dimples contributes to provide stability against wind during flight.
When the combination dimples of the present disclosure are arranged on the surface of the sphere, some of the general circular dimples may be used together as needed, but in cases, general polygon dimples may also be used. This may be a method of increasing a dimple area ratio or a method for an aesthetic effect.
Unlike in
In
As described above, the golf ball according to the present disclosure, in which the combination dimples are arranged on the surface of the sphere, reduces the pressure applied to the entire dimple by making a rapid turbulent transition due to the small bluff body, making it a golf ball with better directionality and superior distance than general polygonal dimples or circular dimples. The golf ball according to the present disclosure, which is arranged on the surface with the combination dimples in which a depth is given to the face having the combined shape of the circle and polygon that are concentric, may reduce the drag by causing a rapid turbulent transition by the vertex portion of the polygon that protrudes with reference to a plane shape of the dimple, and at the same time, may maintain the same directionality as that of a general golf ball including circular dimples, and the flying distance may not decrease even in the low-speed region.
It should be understood that embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment should typically be considered as available for other similar features or aspects in other embodiments. While one or more embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the disclosure as defined by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2020-0080505 | Jun 2020 | KR | national |
