JPS6092782A - Golf ball - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) This invention relates to golf balls, and specifically relates to golf balls that are better than currently commercially available golf balls without violating any of the rules established by the United States Golf Association (LJSGA). It also relates to golf balls that can fly far.

BACKGROUND OF THE INVENTION (Prior Art and Problems) For many years, golf balls have undergone little technological development, with only minor improvements made in their manufacture.

Virtually all golf balls are of the so-called wrapped type. This type of golf ball consists of an elastic rubber ball or a hollow ball filled with liquid.
It has a small center of 1/16 inch (2,54-2.69875 c#). A resilient winding surrounds this center and
A core having a diameter of (4,191 CIR) inches is formed. A shell cover, usually made of balata, is formed by compression molding around the core, resulting in a final ball with a diameter of 1.68 inches.

Beginning in the mid-1960s, many improvements to golf balls were made that were of great interest to the industry. The first major improvement is the new cover material, Surlyn.
This is the introduction of ionomer resin. This was the first plastic material to be widely accepted by the golf industry.

Although Surlyn resin captured a large market, balata was still used, mostly by advanced players.

The second major improvement is the so-called two-piece golf ball. This is 1.45 to 1.61 inches (3,68
3 to 4,0894 Crn) having a polymer unit core therein that is approximately the same size as the wound core. Surrounding this core is another polymeric cover, typically Zurlin ionomer resin. The core is usually compression molded and the cover is either injection molded or compression molded.

The third achievement is an improvement in the aerodynamic shape of the golf ball for greater ball flight. Since the early days of golf,
Improvements in the flight distance of golf balls have always been attempted, and this has been very noticeable over the last decade. Aerodynamic improvements have clearly made the greatest contribution to date to increasing the distance of golf balls without violating USGA regulations.

The USGA publishes rules for the game of golf, and these rules include specifications for golf balls. Compliance with USGA rules is not mandatory, and in fact some companies have declared that they sell "hot" balls that violate USGA rules.

LJSGA is a major manufacturer of golf balls.
Although it would be easy to manufacture "hot j-balls" that violate IA rules, all major manufacturers must do so because breaking the rules will result in the ball being banned from all USGA play.
He humbly adheres to USGA rules. This exclusion is
This is true not only for professional players, but for most club players as well, and has brought about a stigma that is almost criminal. Even on a public golf course, when someone in the group of four tries to play with a ball that violates the rules, they will protest loudly, even if they are playing Duffle Play i7, which is played for $2.

The USGA has established two static tests: ff and size. A golf ball weighs no more than 1.620 ounces (45,927 g) and measures 1,680 inches (4,260 g) in diameter.
72aR). These des i~ have been used by the USGA for many years, and most golf ball manufacturers keep them close to the allowed limits. There are three performance tests imposed by the USGA: speed, total distance, and golf ball symmetry.

The requirement for speed, commonly referred to as the maximum initial velocity, is that a golf ball should travel at 250 feet per second (76,2 m) when measured with equipment approved by the IJSGA.
) must not be exceeded. A 2% error in speed is allowed, so the maximum allowable speed is 255 feet per second (77,724'rrL). This rule has been in effect for many years, and most top manufacturers of golf balls have followed this maximum allowable speed for many years. This is accomplished relatively easily by winding the windings tightly to obtain high compression, or by winding with "fast" threads, which are well known in the golf ball manufacturing art. Most manufacturers don't really try to achieve the maximum allowable speed of 255 feet per second (77,724 m), which is too likely to cause the ball to exceed the allowable value. It has been pointed out that this is because it would be a declaration of breaking USGA rules. Most manufacturers have a safety factor of a
3.250~2 to reduce the risk of "breaking the rules"
Range uu of 53 feet (76,2~77.1'rrL)
As shown in the figure, the average maximum force is set to 3i1 degree, which is a little lower.

The total flight distance is measured by a test known as the Overall Distance Standard, and is 280A7-d (256,032TrL) plus an error of 6% (allowable total flight distance 1ill 296.8 yards (271,39m)) The margin of error was officially 8%, but has recently been lowered to the 6% level.The margin of error may be lowered to 4% (tolerance) as testing techniques improve. The overall distance standard measures carry and roll. Carry is the distance from the dee to the point where the golf ball first touches the ground, and carry and roll are the total distance from the tee to the point where the ball finally rests.The overall distance standard is: Tested using an outdoor USGA-approved device located at USGA headquarters that simulates a club known as a driver.
However, to the applicant's knowledge, there is no golf ball that has come close to the allowable total flight distance of the A-Bar All Distance Standard, and maintains an initial velocity that does not exceed the maximum allowable speed of tJsGA.

Overall distance standard is US
Although the standard used by the GA, the industrial distance standard is often considered to be the total distance vIJ (bright roll) of the ball hit by a driver and a 5-iron. Golf balls like this are USGA
Standards must be followed, but USGA equipment
Since it simulates a shot with a driver,
Two balls that have nearly identical A-bar all distances on USGA equipment can have different values in the driver plus 5 iron test.

The recently established rules for golf ball symmetry are:
It merely states that a golf ball is a tongue that is designed and manufactured to be spherically symmetrical. Death 1, which determines symmetry, is in the development stage. Currently, LJSGA measures the difference in values when the ball hits two different axes. The difference between the currently measured values is
These are the trajectory's bevel angle, pitch distance, and flight time.

A golf ball with a uniform dimple pattern has a U
Balls with non-uniform patterns (see, eg, US Pat. No. 3,819,190) may not pass the SGA test.

In addition to the distance a golf ball travels, another important factor to consider is the height of its trajectory. Unless there is a headwind, commercially available golf balls with the largest chitries in the driver tend to have relatively high trajectories. This high trajectory is due to a relatively high spin rate and an aerodynamic shape that produces relatively high lift and drag coefficients. There are two problems with high trajectory. First, a ball with a high trajectory may be hit in a location where there is a strong crosswind and therefore causes the ball to veer away from the intended direction.

The element that makes the ball even taller is also the so-called tempura (
This tends to result in extremely undesirable conditions such as balls flying too high and lacking distance), hooks and slices.

It is an object of the present invention to provide a golf ball that has a relatively low and flat trajectory and has relatively small horn resistance. A low drag golf ball will fly at a relatively high velocity while maintaining an initial velocity that is within USGA limits. The overall effect of a low and flat trajectory and low drag is
A golf ball has a more interesting distance rule than a ball with a high trajectory. In addition, golf balls impact the ground at shallow angles due to their low, flat trajectories and at high velocities due to low drag.
It has more bounce and roll than a high-trajectory golf ball, and can extend the distance by 1-1 tall compared to what can be achieved with a carry.

Great results of the aforementioned effectiveness are obtained with golf balls that match a particular spin rate with a particular aerodynamic shape.

First, regarding the aerodynamic shape of a golf ball, this has to do with the number of dimples, the spacing of the dimples, and their depth and diameter. According to this invention, the golf ball has approximately 384 dimples. Preferably, the number of dimples is between 376 and 392, although an error of up to about 3% in the number of dimples is acceptable.

The dimples are substantially evenly spaced on the surface of the golf ball. This is 20% on the surface of the golf ball.
It is obtained by arranging the facepiece pattern to form a substantially equilateral spherical triangle yielding 392 vertices. Each vertex becomes the center point of the dimple. For example, British Patent No. 1,381,897 discloses such a dimple center arrangement. The icosahedron-spherical triangle method is used to form the 392 vertices, allowing the dimples to be placed and forming 392 points approximately equally spaced on the golf ball surface.

On top-of-the-line golf balls, four dimples are removed at each pole, three of which are used for the trademark iris and one for the identification number. This gives the most preferred dimple count of 384. If necessary, in addition to omitting dimples for trademark purposes, other minor changes can be made to the placement of the dimples, for example, to facilitate puffing of the parting line, golf balls that are molded. The dimples can be separated at the parting line.

The dimples are substantially part of the spherical surface and have a relationship to each other as shown by the following formula: -4 dimple number.

It has a dimple diameter J3 and a dimple depth.

(554,3(d-X)-37(D-V))
20(138,6(DV) + 92Ci(d
-x ) ) 2=S where: d - average dimple depth D - average dimple diameter x - 0,27! i-0,0041607NV=0.
2790-0.0333 NN=Accurate number of dimples divided by 100 O≦S≦1 The method for measuring dimple diameter and dimple depth is disclosed in the aforementioned British Patent No. 1,381,897. , particularly shown in FIGS. 3-5 and 14-18. The implications of British Patent No. 1,381,897 are hereinafter incorporated by reference. Preferably, at least 95% of the dimples have the diameter and depth specified for a particular number of dimples, especially all of them. However, minor changes for aesthetic or other purposes that do not particularly affect the total flight distance of the golf ball do not impair the technical idea of the invention.

Preferred dimensions for the dimples used in the golf balls of this invention are from about 0.145 inches to about 0.155 inches (0.36 inches).
83 to 0.3937α), and has an average diameter of about 0.010
3 to approximately 0.0123 inches (0.02616 to 0.03
The average depth is 124cm).

(Description of Structure and Effects of the Invention) The present invention will now be described in detail based on embodiments shown in the accompanying drawings.

The drawings show a hemispherical portion of a golf ball according to the invention. Its outer periphery is the ball equalizer 8.

The dimples are arranged in an icosahedron-spherical triangular pattern as described above. According to this invention, the dimples 10 located at the poles of the ball may be left as smooth surfaces for the trademark (=J). The dimples 12 may be similarly left open for the identification number. Good. Dimple 10.12
and 14 can be left open to be folded (in Example 8). Dimple IQ, 12 J
:i and 14 may be present as in Example 9.

Dimple 18 can have a different diameter than the other dimples, as shown in Example 10).

The second fundamental requirement is the spin rate of the golf ball. Spin rate varies as a function of golf ball compression. The term "compression" as used herein is well known in the golf ball industry.

Compression is sometimes used as PGA compression and is expressed as a baseless unit of the scale known as the PGΔ compression school. 90-100 Ml quasi compression is 1
-Used in almost all Tsubu class golf balls. Many manufacturers offer 90 compression and 10
Both 0 compression models are available. According to the invention, the spin rate of a golf ball having a nominal compression between 90 and 100 is approximately 11°.
230 feet per second (70,1 m) with a clubface angle of 13° to the vertical that produces a launch angle of
When hit at a speed of about 2,900 rpm. As a practical matter, at a minimum spin rate, the golf ball will
Under this condition, the speed reaches approximately 200° rpm. Equipment for determining hitting parameters is commercially available from companies such as True Temper Corporation. Apparatus suitable for making spin rate measurements is disclosed in U.S. Pat.
No. 063.259. This patent also discusses the interrelationship between launch angle and spin rate.

The spin rate of the golf ball of the present invention is slightly higher than the spin rate of a golf ball coated with a conventional varnish. When struck at a speed of 230 feet per second with a tool of approximately 3
000 to about 3500 rpm.

However, it has been found that such balata coated balls can be spun at the spin speeds required in this invention by increasing the size of the liquid center and the hardness of the coating. The center of a rolled golf ball typically has a diameter of 1 to 11/16 inches (2.54 to 2.69875 cm). According to this invention, the center is at least 11/8 inches (
It is preferable to increase the height to 2,8575 cm). If you increase the center diameter to J: compared to the conventional ball,
It is effective in reducing the spin speed of a golf ball.

Golf ball coatings are commonly known as balata. Balata can be found in nature, but it can also be synthesized. In both cases, transpolyisoprene is the ingredient. Although this is a relatively hard material, it is very expensive, costing $5.50 per bond (
The price ranges from about $12.00 (for synthetic products) to about $12.00 (for natural products). In comparison, natural rubber (100% cis isoprene) costs about $0.50 per bond. Natural rubber is a flexible material and is mixed with balata at 50% or slightly more to reduce the overall cost of the coating. Other materials may also be mixed with the balata along with or in place of the rubber to reduce the cost of the coating. Notable among these materials are gutta percha, butadiene and synthetic rubber. To obtain the spin speeds of this invention, at least both 90% transpolyisoprene is used, more preferably at least both 95% transpolyisoprene is used, or most preferably at least both 99% transpolyisoprene is used. used. The combination of a large liquid center and a hard balata coating has shown that wrapping the balata coating is an excellent way to obtain the spin rates of the present invention on a ball. Of course, it is possible to obtain the required spin speed by other methods as well.

The wound-core golf balls of this invention have an aerodynamic shape and spin rate, and commercially available wrap-arounds of similar compression have lower and flatter trajectories than core-type golf balls. However, it was also found to have greater carry distance and greater total distance (this is true for both the driver and the 5-iron). Regarding trajectory, a height of 1/2 yard (0,4572771) when struck at an angle of 136 at a speed of 230 feet per second (70,1 m>) is considered to be significant. The ball according to the invention Commercially available wraps are less than those of balata-coated golf balls, ranging from 1 to 11/2 yards (0.9144 to 1.371 yards).
6TrL) has a low trajectory. In terms of carry distance (driver and 5-iron tests), golf balls according to the invention have less carry distance than commercially available golf balls, whether rolled tee or two-piece, balata-coated or Surlyn-coated. Both 5 yards (4,5
121rL> can be achieved. The structure of the present invention will be further explained below with reference to Examples.

Example 1 A group of golf balls was obtained. The golf balls are manufactured by the applicant and bear the trademark T 1tleist Pro.
It is sold under the name Trajectory. These golf balls have a so-called liquid center, which is well known in the golf ball industry. The liquid center is a hollow sphere with an outside diameter of 1 to 11/1 G inches (2.54 to 2.69875 CII+). The hollow sphere is completely filled with liquid. The center is covered with 0.22" x 1/16" (0,5588aRX O,15875011) elastic thread and has a diameter of 1.610" (4,0
894α) winding [to be made into a ball. Its top surface is
Molded with a coating consisting of the following components: Resin; 76.2%, Resin component: 84% transpolyisoprene, 16% natural rubber; Filler: 22.5%;
Other; 1.3% The molded golf balls are processed and painted in standard fashion. The diameter of the finished golf ball is 1
．． 680 inches (4,2672 cIR).

This value is an average value. Actual value may vary by 0.003 inch (0.00762 cm).

The golf ball comprises 324 dimples uniformly distributed over the surface of the golf ball centered at the vertices of an icosahedral-spherical triangular array as described in British Patent No. 1,381,897. , except that the four vertices at each pole of the ball have no dimples to form a smooth surface for marking the trademark and identification number, and these vertices have no dimples to separate the dimples about the molded parting line. has been slightly rearranged to form an equator. The dimples have a diameter of 0.146 inch ± 0.002 inch (0.37084 on ± 0.00508 cm) and 0.0122 inch ± 0.0003 inch (
It has a depth of 0.030988cm±0.0007621).

Example 2 - A group of golf balls were made according to the method of this invention. The golf ball had the same type of liquid-filled center as the golf ball of Example 1, used the same elastic thread as in Example 1, and had the same rolled ball diameter of 1.610 inches (1.610 inches). 4,089α).

In this case, however, the golf ball was made to meet the parameters of this invention.

The center size was increased to 11/8 inches (2,85750). The composition of the coating molded onto the wrapped ball was changed to 100% transpolyisoprene polymer as follows: Resin; 76.7%; Resin composition; 100% transpolyisoprene, 0 natural rubber. , filler; 22.0%.

Other; 1.3% Fillers and other compositions are the same as in Example 1, except for slightly less filler. The molded balls are processed and painted in standard fashion. The diameter of the finished ball was 1,680 inches (4,2672 cm).

As in Example 1, the diameter misjudgment tolerance was up to 0.003 inches (0.00i'62α).

Further, according to the present invention, the golf ball uses an icosahedron slope triangular pattern and has three triangles arranged at approximately equal intervals on the surface of the golf ball, as in the golf ball of Example 1.
It has 84 dimples.

Similar to the golf ball of Example 1, no dimples were used at the four vertices to create a smooth surface for the trademark and identification number on the eight poles. The top of the dimple is
The molded parting lines are slightly shifted and rearranged to form an equator. Dimples are 0.146 inch ± 0.002 inch (0.37084 cm ± 0.0
050kii) diameter and 0.0115 inch ±0.
0003 inches (0,02921α±0,000762
CIR).

Comparative Tests The finished golf balls of Examples 1 and 2 were compared for a number of properties. Balls were selected from examples that were statistically comparable to the LISGA standard, eg, size, weight, and initial velocity. Each ball selected is 1.61
0 to 1,620 ounces (45,6435 to 45,927
9) multilayer, 1.680 to 1,690 inches (4,26
72 to 4.2926 am) and 25 per second
3.0-253.5 feet (77,1144-77.
It had an initial velocity of >2668 m. These changes in size, weight, and initial velocity did not have a significant overall significance on the number of balls tested.

The ball was first examined for its spin rate. This was done for both the driver and the 5 iron.

A ball hit with a driver has a launch angle of 11° and a ball hit with a 5 iron has a launch angle of 21". The spin rate is
No. 33,259, using equipment of the type disclosed in U.S. Patent No. 33,259.

Carry distance and roll distance (carry a3 and roll) were determined by field testing using a device commonly known in the golf ball industry as a dual pensulam. A dual pensulam device has pensulams on both sides of a motor so as to draw a pensulam trajectory, and each pensulam strikes two pensulams at the same time, one at a time.

The ball is maintained at a temperature of 70@F (21,111...C).

Two balls at −1 m are hit into the oven field by the pensulam, and the gully distance and total distance are individually observed and recorded by the operator. Eight balls are hit on each side of the device. in this case,
A series of eight balls of Example 1 is struck on one side of the device and a series of eight balls of Example 2 is struck simultaneously on the other side. After rolling, the 16 balls are collected and returned to the device. These are sorted and replaced with beaten pensulum. Another measurement is taken, the balls are collected and the procedure is repeated two more times. Each of the eight balls in each example would now be hit four times, for a total of 32 times for both pensulum, and 16 times for each vent column. This number of blows produces meaningful results in terms of H1, changes in winding, and differences in temperature.

Almost cancels out device or penschlum differences.

This is particularly true when the balls of the two embodiments are hit at the same time;
This is because the pensulam can be replaced throughout the four-Test series.

The procedure just described is used for both driver and 5-iron distance tests. The dual pensula has an adjustable striking surface. To race the driver, a launch angle of 11° is used. 1
A launch angle of 1° is obtained by using a striking surface with an angle of 13° to the vertical. A launch angle of 21° was used to trace the 5 iron. A launch angle of 216 was obtained by using a striking surface with an angle of 26° to vertical. The results of the spin speed trace and drive distance test are as follows.

Ball of Example 1 Ball of Example 2 (Tight Strike (this invention) Pro Traziex 1-Re) Spin "a" (rpm) 11' 3135 2799 2165310 4788 Carry distance (17-degree) 11° 251,3 253.7 <229.78872m><231.98328
m>21' 168.8 172.3 <154+35072m> (157,55112
m >11' + 21' 420.1 426.0 (3
84,13944TrL) (389,5344TrL
) Total flight distance (carry Dobe) (A7-de) 11° 268.5 27G, 3 (245,5164771) (252,64872m
)21' 179.1 184.7 (163,76904711) (168,88968
m) 11'+21' 447.6 4 (31,.

(409,28544m) (421,5384711
>Example 3 Golf balls made according to Example 2 are compared to balata-coated golf balls from various manufacturers in the 1-3 class using the distance test set out in the previous section as "Comparison Test." There are significant differences between the tests because the tests were conducted under different environmental conditions. The comparable golf balls were current production balls provided by manufacturers to professional tours. The test results are as follows.

Initial velocity Carry distance - U SGA 11° 21° 11'+21° (21
6,62136m) (139,62888) (35
6,25024) Reson T 100 253.1 2
36.9 152.7 389.6C226,4054
4m) (145,93824) (372,3436
8) (203,9112m) (130,302) (
334,2132) Redenram Pro Tour 252.8
．． 223.0 142.5 365.5 (214,6
0968m) (136,06272) (350,6
724) (211,40928m) (146,304
) (357,71328) Bun Avex 100
250.8 231.2 160.0 391.2 (2
20,64472m) (i50.51024) (3
71,15496) (224,85096m) (15
0,4188) (375,26976)r Regar
i o O254,024,5,9164,5410,
4 (230,97744m) (148,40712)
(379,384,56) Golf ball by Sekimon
252.8 252.6 162.3 414.9 Total distance (Keyery - Dobe slope) 11° 21' 1
1°+21° (221,1010l92 (143,37792)
(364,474)84)241.8 156.8 3
98.6 (235,73232m) (150,69312)
(386,42544) 257.8 164.8 42
2.6 (206,6544m) (131,85648)
(338,60232)226.1 144.2 37
0.3 (219,27312m) (138,0744) (
357,34752) (217,17m) (151
,24176) (368,41176)237.5
165.4 402.9 (228,87432m) (156,17952)
(385,05384) 250.3 170.8 42
],,](2232,34904m (150,418
8) (382,76784) 254.1 164.5
41L6 (243,32184m) (153,162) (3
96,48384) 266.1 167.5 433.
6 Examples 4 and 5 These examples demonstrate that the present invention can be used with a coating of ionomeric resin 1 such as DuPont's Surlyn resin. A series of golf balls were made in the same manner as Examples 1 and 2, and Examples 4 and 5.
It was called. In each case, the ionomer resin replaced the coated paulownia wood with the resin of Examples 1 and 2. The size of the rolled ball was 1.58 inches (4,0132G), and the cores of Examples 4 and 5 were:
Made in the same way and from the same materials. These balls were compared for -C1--tal flight distance (carry and roll) using the procedure described above, and the results are as follows.

Ball of Example 4 Ball of Example 5 Distance (carry Dobe Gari) Yard 11 @ 246.6 251.0 (225,49104m) (229,5144m
)21' 183,6 184.3 (167,88384) (168,52392>11
@ +21' 430.2, 435.3 (393,3
(398,03832) Examples 6 and 7 These examples demonstrate that the invention can also be used with rigid cores. A series of golf balls were made similar to Examples 4 and 5 and are referred to as Examples 6 and 7.

In both cases, the rigid core is replaced by the rolled core of Examples 4 d3 and 5. The rigid core was made according to the suggestions of British Patent No. 1,364,138. These balls were compared for total flight distance 1111 (carry and roll) according to the procedure described above, and the results are shown below.

Ball of Example 6 Ball of Example 7 (with a rigid core (Ball of Example 5 based on Example 4 with a rigid core) Total flight distance (Carry Dobe) Yards 11' 274 ,8 275.8 (251,27712m) < 252.19152m
>21” 171.9 175.6 (157,18536) (160,56864)11
' + 21' 446,7 451.4 (408,4
(412,76016) Example 8 A ball having 312 dimples instead of 384 dimples was made in the manner of Example 2. This number of dimples is obtained by omitting the dimple shown at 14 in the drawing. Although only the dimples on one hemisphere of the golf ball are shown in the drawing, the total number of omitted dimples is 12 and 37.
2 dimples are left on the golf ball. Dimples are 0.155±0.002 inches (0.39 to 31±
0.00508α) diameter and 0.0120±0.00
03 inches (0,03048±0.0007θ2CI+
) has a depth of The spin rate of the golf ball was the same as that of Example 2, and in the distance test, the results were not statistically different from those of Example 2.

Example 9 The method of Example 2 reduces the number of dimples from 384 to 392.
and was repeated. This is accomplished by including 10 dimples in the trademark identification area and 12 dimples in the numeric identification area on each hemispherical surface of the golf ball. The spin speed of the golf ball is as shown in Example 2.
is the same as that of a golf ball. The distance test results were not statistically different from those of Example 2.

Example 10 A golf ball was made in the manner of Example 2, except that the dimples marked 18 in the drawings were 0.140±0.
0.002 inches (0.3556±0.00508 mm) in diameter with the remaining dimples being 0.160±0.0
The difference is that the dimples have a diameter of 0.02 inches (0.4064±0.00508cIR).The average diameter of the entire dimple is 0.151±0.002 inches (0.38354±
0.005080), which is δ. The spin rate of the golf ball is the same as that of Example 2Q. In the distance test, the golf ball of this example was superior to golf ball 1 of example 2 in terms of δ1.

Several embodiments have been described above, but variations and modifications to these embodiments can be easily made and may deviate from the technical idea of the present invention.

[Brief explanation of the drawing]

The drawings show a hemispherical part of the golf ball according to the invention. 8・・・・・・・・・・・・・・・・・・・・・Evenly divided yen 10, 12.14.18...Dimple) ) Continued from page 1 0 Inventor John W. Amezie Efson
56 Ortrole Road, Marion, Massachusetts, United States of America

Claims (1)

[Claims] (1) A golf ball having a core and a coating,
When struck at a speed of 70.1 m/s by a tool with a face angle of 136 to the vertical, it hits approximately 2900 r.
(d is the average dimple Depth, D is average dimple diameter, A golf ball characterized by satisfying 1). (2) The golf ball according to claim 1, wherein the core is a core covered with an elastic thread. (3) The golf ball according to claim 2, wherein the coating is a resin and contains at least 95% trans polyisoprene. (4) The golf ball according to claim 3, wherein the coating resin is 100% trans polyisoprene. (5) The golf ball has a center diameter of at least 11/8 inch (2.8 inches).
575cm) ±0.003 inch (0,00762cm
) The golf ball according to claim 3 or 4, which is: (6) The golf ball according to claim 1, wherein the coating is an ionomer resin. (7) The golf ball according to claim 6, wherein the core has a unit structure. (8) The golf ball according to claim 1 or 3 or 6 or 7, wherein the number of dimples is 376 to 392. (9) Dimples: 0.145 inch < 0.36
83 m) and 0.155 inches (0,3937 cm), with a further 0.0103 inches (0,0
2616 on) and 0.0123 inch (0,03124
Claim 8 having an average depth between
The golf ball described in Section 1.