JPH1043342A - Golf ball for practicing golf shots - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a golf ball which can be used favorably especially in a city driving range built in a limited space, as the feeling of impaction is good, the trajectory can be made sufficiently low, and the decline in flight distance can be reduced. SOLUTION: In a golf ball with many dimples formed on its surface, dimples satisfying Dm /Dp =10 to 15 account for 80% or more of the total number of dimples when the weight is 46.5 to 49.0g and the amount of deformation of the ball at constant load of 100kg is 2.5 to 4.0mm, wherein Dm is the diameter of each dimple and Dp is the depth.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a practice golf ball which can achieve a low trajectory without deteriorating the flight distance performance, has a good feeling, and can be suitably used particularly in a narrow golf practice range. .

[0002]

2. Description of the Related Art
In cities, etc., so-called urban golf practice ranges, where the site is limited by ball-proof nets due to location requirements, are often used, but practice golf balls used in such practice ranges have high trajectories. If the ball is easily formed, the ball may jump out beyond the ball-proof net and give danger to the surroundings.

[0003] Therefore, there is a need for a practice golf ball that provides a low trajectory with a low risk of jumping over a ball-proof net.

[0004] From such a point, Japanese Patent Laid-Open No. 4-11796
No. 9 discloses a weight of 43 to 48 g and a diameter of 1.65 to 1.65 g.
A practice golf ball having a size of 71 inches, 300 to 550 dimples, and a total dimple volume of 400 to 600 mm ³ has been proposed, but there is still room for improvement in trajectory height.

[0005] The practice golf ball not only has a low trajectory but also has a sufficient flight distance, has a good feeling, and gives a good feeling when shot. Although it is necessary to do so, conventional practice golf balls have not been sufficiently considered in this respect.

The present invention has been made in view of the above circumstances,
It is an object of the present invention to provide a practice golf ball that provides sufficient low trajectory while maintaining the flight distance performance and has a good hit feeling.

[0007]

Means for Solving the Problems and Embodiments of the Invention The present inventors have conducted intensive studies in order to achieve the above-mentioned object, and as a result, a normal golf ball for competition must satisfy the standards set forth in the Rules of Golf. It is specified that the weight should be 45.92 g or less. However, when obtaining a practice golf ball, it is not always necessary to satisfy this standard. The trajectory of golf balls has been reduced.

That is, 46.5 which is heavier than the upper limit of the golf rules.
By obtaining a golf ball weighing ４９49.0 g, the effect of gravity acting on the ball during flight was enhanced, the excessive climb of the ball was suppressed, and the trajectory was reduced. However, the gravitational effect alone does not achieve sufficient trajectory reduction, and there is a possibility that the flight distance may be reduced. For this reason, as a result of further study, a sufficient dimple depth was taken, and in particular, the ratio of the dimple depth to the dimple diameter was set to a range of 10 to 15 for most of the dimples, that is, 80% or more of all the dimples. Effectively, dimple depth 0.20
It has been found that by setting the distance to 0.35 mm, sufficient reduction in trajectory can be achieved while suppressing a decrease in flight distance.

Further, when the ball weight is simply increased as described above, the impact force received by the hitter at the time of impact becomes larger than that of a ball having a normal weight, so that the hit feeling at the time of play is not reproduced, and the sense of practice is not obtained. Is not utilized in actual play, but when the amount of deformation when a 100 kg load is applied to the ball is formed to be 2.5 to 4.0 mm, the ball has an excellent hit feeling similar to that of a normal competition ball. This has led to the achievement of the present invention.

Therefore, the present invention provides a golf ball having a large number of dimples formed on its surface, and having a weight of 46.5.
４９49.0 g, the amount of deformation of the ball under a constant load of 100 kg is 2.5-4.0 mm, and when the diameter of each dimple is D _m and the depth is D _p , D _m /
Dimples satisfying D _p = 10 to 15 to provide a practice golf balls, characterized in that 80% or more of the dimples total number.

Hereinafter, the present invention will be described in more detail. The practice golf ball of the present invention can be formed as a one-piece solid golf ball, a two-piece golf ball having a solid core covered with a cover, and the like, and its weight is 46.5. -49.0 g, especially 47.0-48.8 g. If the weight is more than 49.0 g, the gravity applied to the ball is too large to greatly reduce the flight distance, and the impact force at the time of impact is large, so that the hit feeling becomes very poor,
If the weight is less than 46.5 g, it is not possible to sufficiently reduce the trajectory due to the gravitational effect, and the trajectory tends to be high, so that the object of the present invention cannot be achieved.

In this case, the ball diameter is appropriately selected and is not particularly limited, but may be the same as a normal practice golf ball, and is 42.3 to 43.0 mm, more preferably 42.3 mm.
It can be 5 to 42.8 mm.

Further, the golf ball of the present invention has a
g The amount of deformation of the ball under a constant load is 2.5 mm or more,
Preferably 2.7 mm or more, more preferably 2.8 mm
The above is formed. If the deformation amount is less than 2.5 mm, the impact force at the time of impact becomes large, and the hit feeling becomes poor, so that the object of the present invention cannot be achieved. The upper limit of the deformation is 4.0 mm or less, particularly 3.8 mm or less. If the upper limit is greater than 4.0 mm, the ball is poorly separated at impact and impairs the feel at impact.

Further, in the golf ball of the present invention, a large number of dimples are formed on the surface thereof. In this case, the diameter of each dimple formed on the surface of the golf ball is D.
_m, when the depth was set to _{D p, D m / D p} = 10~15, preferably dimples satisfy 11 to 14.5 is more than 80% of the dimples total number, preferably formed so as to occupy more than 82% This suppresses a decrease in the flight distance that cannot be obtained by the gravitational effect alone, and enables a favorable low trajectory. On the other hand, when the ratio of D _m / D _p is less than 10 is 80% or more, the depth is too deep with respect to the diameter of the dimple. on reduction of a marked, the marking failure occurs during the manufacture of the golf ball, and if that D _m / D _p is more than 15 is 80% or more, or up wipe the ball with dimples is too shallow, high It becomes a trajectory and cannot achieve the object of the present invention.

Further, in the present invention, the depth D _p of the dimples distance performance of the golf ball, in view of the marking or the like during low trajectory and manufacturing, 0.2～0.35Mm,
In particular, it is preferably 0.22 to 0.33 mm. When the depth D _p is less than 0.2mm, or blown up a golf ball at the time of the strike, there is a me to become a high trajectory, also, and more than 0.35mm, sufficient flight distance is too low trajectory In some cases, it may not be possible to obtain a mark, and marking may not be performed properly.

The total number, shape and number of types of dimples formed on the golf ball of the present invention are not limited, but the total number is preferably 300 to 460, particularly preferably 340 to 440. In addition, the diameter and the depth are different.
It is preferable to form more than one kind, especially two to four kinds of dimples from the viewpoint of flight distance characteristics. The arrangement of the dimples may be the same as that of a normal golf ball.

Further, the dimple has a dimple space volume below a plane surrounded by an edge of each dimple.
If the said plane and a bottom surface and a value obtained by dividing the cylinder volume to the height of the maximum depth of each dimple from the bottom and V _0, be formed to be V ₀ = 0.40 to .65 Preferably, if the value of V ₀ exceeds 0.65, the ball may blow up and stall, and a sufficient flight distance may not be obtained. Could be

Here, the dimple shape will be described in more detail. When the dimple planar shape is circular, FIG.
As shown in FIG. 5, a virtual sphere 2 having a ball diameter is set on the dimple 1 and a sphere 3 having a diameter smaller than the ball diameter by 0.16 mm is set. An intersection 4 between the circumference of the sphere 3 and the dimple 1 is obtained. A series of intersections 6 between the tangent line 5 at the intersection 4 and the virtual spherical surface 2 is referred to as a dimple edge 7. In this case, the setting of the dimple edge 7 described above is because the edge of the dimple 1 is usually rounded, and without such a setting, the exact position of the dimple edge cannot be determined. Dimple diameter D in the present invention
_m in the case of the dimples is the diameter of the enclosed surface (in FIG. 1 round) at the edge 7, also the depth D _p is the length to the bottom of the dimple from the center of the D _m.

Further, in order to obtain the above V ₀ value, FIGS.
As shown in the figure, a plane surrounded by the edge 7 (circle:
The volume V _p of the dimple space 9 below the diameter D _m ) 8 is obtained. On the other hand, the dimple space for the volume V _Q of the cylinder 10 having the flat surface 8 as a bottom surface and the height of the maximum dimple depth D _p from the flat surface 8 as a height. It is calculated as the ratio of the volume V _p.

[0020]

(Equation 1)

If the plane surrounded by the edge 7 is not circular in dimple plane shape, the maximum diameter (or plane maximum length) of the dimple is determined, and the dimple plane is defined by this maximum diameter (maximum length). The maximum depth D _m is the distance from the point having the maximum depth of the dimple to the plane, and V ₀ is calculated in the same manner as described above based on these rules. .

As described above, the golf ball of the present invention is formed as a one-piece solid golf ball, a two-piece solid golf ball, or the like. The materials for obtaining these balls and the manufacturing method are known materials and manufacturing methods. be able to. When obtaining a two-piece solid golf ball, it is recommended that the cover has a Shore D hardness of 50 to 70 and a thickness of 1.0 to 3.0 mm from the viewpoint of durability and hitting feeling.

[0023]

As described above, the golf ball of the present invention has a good feeling at the time of impact, has a sufficiently low trajectory, and suppresses a decrease in the flight distance. It can be suitably used in an urban golf driving range to be constructed.

[0024]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[Examples 1 to 4, Comparative Examples 1 and 2] Using a rubber base having the composition shown in Table 1, kneading was carried out with a kneading roll.
A one-piece golf ball (Example 1 and Comparative Example 1) was obtained by heating and pressing at 25 ° C. for 25 minutes. Table 1
After kneading the rubber base material, the mixture was heated and pressed at 155 ° C. for 20 minutes to obtain solid cores (Examples 2, 3 and Comparative Example 2). In Examples 2 and 3 and Comparative Example 2, the obtained solid core was covered with a cover material (ionomer resin, manufactured by DuPont-Mitsui Polychemicals, H1706).
/ H1605 = 50/50 blend) to give a two-piece golf ball. Dimples as shown in Tables 2 and 3 were formed on the surfaces of these balls.

A marquee is applied to each of the obtained golf balls.
The following method for each 10 golf balls
Depending on the presence or absence of mark failure, maximum trajectory altitude,
The reach, trajectory and feel were evaluated. Table 3 shows the results.
In Table 3, the measurement and evaluation of various properties are based on the following criteria.
I went there.Mark defects (mark defect rate) Visual inspection of golf ball markings
The occurrence rate of marking defects was determined.Maximum ballistic altitude and maximum altitude reach Loft angle 11 with a striking robot (Trutemper)
を The trajectory when hit at a head speed of 45 m / s
The highest altitude was sought by taking pictures. Feel ◎: soft and good ○: normal △: slightly hard

[0027]

[Table 1]

[0028]

[Table 2]

[0029]

[Table 3]

As is clear from the results shown in Table 3, the golf ball of the present invention has a good hit feeling, a low maximum altitude, a low trajectory, and a decrease in the flight distance due to the low trajectory. It was confirmed that no scum was found.

[Brief description of the drawings]

FIG. 1 is an explanatory view (cross-sectional view) illustrating a maximum diameter D _m and a maximum depth D _p of a dimple.

FIG. 2 is an explanatory diagram (cross-sectional view) illustrating a calculation method of V ₀ .

FIG. 3 is an explanatory diagram (cross-sectional view) illustrating a method of calculating V ₀ .

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Dimple 2 Virtual sphere 3 Sphere 4 Intersection 5 Tangent line 6 Intersection 7 Dimple edge 8 Plane 9 Dimple space

Claims (4)

[Claims] 1. A golf ball having a large number of dimples formed on a surface thereof has a weight of 46.5 to 49.0 g and a deformation amount of the ball at a constant load of 100 kg of 2.
When the diameter of each dimple is D _m and the depth is D _p , the dimple satisfying D _m / D _p = 10 to 15 occupies 80% or more of the total number of dimples. Practice golf ball. 2. The dimple depth D _p satisfying D _m / D _p = 10 to 15 is 0.20 to 0.35 mm.
A practice golf ball as described. 3. A one-piece golf ball.
Or the practice golf ball of 2. 4. The practice golf ball according to claim 1, which is a two-piece golf ball having a core covered with a cover.