JPH09290034A - Golf ball and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the flight distance and aerodynamic symmetric property by obtaining the volume of a virtual ball assumed to have no dimple on its spherical surface and the total capacity of dimples on the ball surface, and setting the ratio of the total capacity of all dimples against the ball volume in a specific range. SOLUTION: The total capacity ratio VR of all dimples against the ball volume expressed by (B/A)×100 is set in the range of 0.6%<VR<1.5%, where Amm<3> is the volume of virtual ball assumed to have no dimple on its surface, and Bmm<3> is the total capacity of all dimples provided on the ball surface. 12 virtual spherical regular hexagons 4 and six congruent virtual spherical regular squares 5 are drawn on the ball surface, and three diagonal lines 6 are drawn on each regular hexagon 4 to divide each regular hexagon 4 into six virtual spherical triangles 7 respectively. Dimples are arranged at the same dimple layout in the triangles 7 and the regular squares 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a good aerodynamic symmetry that provides a good flight distance, does not cause a difference in flight distance and trajectory depending on the hitting position, and exhibits stable flight performance. And a method for manufacturing the golf ball.

[0002]

2. Description of the Related Art The dimple arrangement and dimple shape (diameter, depth, cross-sectional shape, etc.) of a golf ball have a great influence on the flight performance of the golf ball. Various geometrical arrangement methods have been proposed in which a large number of dimples are evenly or densely arranged on the surface of a golf ball in order to improve the flight performance.

In this case, the most demanded by the player for the flight performance of the golf ball is to increase the flight distance, and many players desire to further increase the flight distance.

Aerodynamic symmetry is another important flight performance of golf balls. This is also stipulated in the Golf Rules (Japan Golf Association) Supplementary Rules, III, and Ball (C), and requires that there is no difference in flight distance or trajectory no matter where the ball is hit. It is a thing. Conventional golf balls currently on the market have this symmetry in the range specified by the above rules, but not yet reached a level that is sufficiently satisfied by all players, and aerodynamics has not been reached. Further improvement of the dynamic symmetry is also desired.

That is, the ordinary golf balls currently on the market have a so-called seam line, and this seam line is one of the causes of degrading aerodynamic symmetry. This seam line is a virtual golf ball that is molded with a two-sided mold having a hemispherical molding surface, so that the dimples formed at the seam between the mold and the mold do not intersect. Although it is a great circle and is unavoidably present in a golf ball due to its manufacturing, in a golf ball having this seam line, as shown in FIG. Center point d of ball a
A pole striking f (Fig. 8 (A)) so that a straight line e passing through is the rotation axis, and a straight line h passing through both poles (poles) and the center point d when the seam line b is the equator is the rotation axis. Therefore, a difference in the trajectory and the flight distance of the ball is likely to occur between the seam striking (i.e., FIG. 8B).

In this case, if a slightly aerodynamically asymmetric ball is used, this asymmetry may lead to destabilization of the shot, especially at the level of advanced players and professional golfers. The improvement of the aerodynamic symmetry is also an important issue in improving the flight performance of the golf ball.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a golf ball having excellent flight performance with improved flight distance and aerodynamic symmetry, and a method for manufacturing the golf ball. .

[0008]

Means for Solving the Problems and Modes for Carrying Out the Invention In order to achieve the above object, (1) in a golf ball having no great circles that do not intersect with dimples on the surface, the spherical shape of the ball the volume of a phantom sphere assuming that dimples are not in the surface and Amm ^3, the sum of the whole golf ball dimple volume provided on the surface of the ball when the Bmm ³ with (B / a) × 100 the ratio V _R of the total volume of all the dimples to the ball volume is shown, the golf ball, which is a _{0.6% <V R <1.5%} , 12 pieces of it congruent to (2) ball surface A virtual spherical isosceles hexagon and six congruent virtual spherical isosceles tetragons are surrounded by four virtual spherical isosceles hexagons, and four sides of each virtual spherical isosceles square are the virtual spheres. Equilateral Each of the four virtual spherical isosceles hexagons that surrounds the shape is drawn in common with each side, and three diagonal lines are drawn on each of the all virtual isosceles hexagons to create six isosceles hexagons. By dividing the ball surface equally into triangles, the ball surface is divided into 72 virtual spherical triangles and 6 virtual spherical isosceles quadrangles, and the inside of each of the virtual spherical triangles has the same dimple arrangement, and each of the imaginary spherical isosceles squares. The golf ball of (1) above, wherein the dimples are arranged on the surface of the ball so that the inside has the same dimple arrangement.
And (3) the golf ball according to the above (2), in which 72 virtual spherical triangles and 6 virtual spherical isosceles tetragons are intersected by the same number of dimples on all sides.

That is, in the golf ball of the present invention, the dimples are arranged so that there are no great circles that do not intersect with the dimples on the surface, and the decrease in symmetry due to the presence of the seam line is caused. is prevented, dimples, by the ratio of the total volume of all the dimples to the ball volume (total dimple volume ratio) V _R is arranged so that the above value, the volume ratio of the dimples is optimized, distance Is achieved.

In this case, as in (2) above, the ball surface is divided into 72 virtual spherical triangles and 6 virtual spherical equilateral quadrangles, and the inside of each virtual spherical triangle has the same dimple arrangement, and By arranging the dimples so that the inside of each of the virtual spherical isosceles quadrangles has the same dimple arrangement, the dimples can be arranged so that a uniform dimple effect can be obtained over the entire surface of the ball. As described in (3) above, the same number of dimples intersect all the sides forming the 72 virtual spherical triangles and the 6 virtual spherical equilateral quadrilaterals. By arranging the dimples, the distance between the dimples becomes uniform over the entire ball, and a golf ball having extremely excellent aerodynamic symmetry can be obtained. A.

The present invention also provides, as a manufacturing method for obtaining the golf ball of the present invention, (4) a pair of mold halves each having a large number of dimple forming projections formed on the inner surface of a hemispherical cavity are separated. A spherical cavity having a large number of dimple forming protrusions formed on the inner peripheral surface of the core is arranged and held at the center of the spherical cavity by joining as much as possible. In a method of manufacturing a golf ball, in which a cover molding material is supplied to a gap formed between the two surfaces to mold a cover layer having a large number of dimples around the core. A plurality of pin insertion grooves communicating with the cavity are provided, and the dimple forming pin is arranged in the pin insertion groove so that the tip of the dimple forming pin projects into the cavity. The dimple forming protrusions are formed on the parting line, and a cavity having no great circle on the inner peripheral surface that does not intersect with the dimple forming protrusions is formed, and the dimple forming protrusions (1) to (3) are formed. (5) A method for manufacturing a golf ball, which comprises manufacturing the golf ball according to any one of (1) to (5), and (5) arranging the dimple forming pin so that the dimple forming pin can advance and retreat, and advancing into the cavity of the mold to form the dimple forming pin. Hold the core in the center of the cavity with, and in this state, supply the cover molding material into the gap formed between the core and the inner peripheral surface of the cavity, and immediately before the cover molding material is completely filled. There is provided the method for producing a golf ball according to the above (4), wherein the dimple forming pin is retracted to the dimple forming position to form the dimple on the parting line of the mold.

That is, the above-mentioned manufacturing method of the present invention uses a two-sided molding die comprising a pair of dies having a hemispherical cavity, and a core is placed in the cavity of the die. When the cover molding material is injection-molded around the core and the dimples are formed on the cover, the dimple molding convex portions formed on the inner peripheral surface of the cavity of the mold are used to form the above-mentioned (1) to (3). ) Is provided so as to satisfy the dimple arrangement, and a dimple forming pin is arranged on the mating surfaces of both molds so that the tip of the dimple forming pin projects into the cavity, and the cavity is formed at the tip of the dimple forming pin. By forming a dimple forming convex part on the parting line and forming a dimple on the parting line of the mold at the tip of the dimple forming pin, the dimples intersect the dimples on the surface. There is no great circle is that to obtain a golf ball that does not exist even one.

In this case, as in the above (5), the dimple forming pins are arranged so as to be able to move forward and backward, and the core in the cavity is held at the center of the cavity until just before the cover forming material is filled. It can be used as a support pin.

Hereinafter, the present invention will be described in more detail.
The golf ball of the present invention, as described above, dimples no any great circle that does not intersect, and the ratio of the total volume of all the dimples to the above ball volume (total dimple volume ratio) V _R is 0.6 % <those configured such that V _R <1.5%.

The total volume ratio V _R of the dimples is the sum of the volumes of the dimples provided on the surface of the ball as a whole, assuming that the volume of the phantom sphere is Amm ³ assuming that the spherical surface of the ball has no dimples. To Bmm ³
Is a value represented by (B / A) × 100.
Here, the volume A of the phantom sphere can be obtained by A = 4/3 × (radius of phantom sphere) 3 × π as in the case of obtaining the volume of a normal sphere, and the total dimple volume B For example, when there is one kind of dimple, it is calculated by (volume of one dimple (VD)) × (total number of dimples), and when there are a plurality of kinds of dimples, the sum of the volumes of the respective dimples is similarly calculated. Then, these can be added and added. In this case, the dimple volume VD is, as shown in FIGS. 1A and 1B, the diameter of the circular virtual plane 3 surrounded by the outer edge 2 of the dimple 1 is Dm, and the deepest part of the dimple 1 is virtually the same. A straight line passing through the center of the plane 3 is the y-axis, and a straight line on the virtual plane orthogonal to the y-axis is x.
It can be obtained by the following formula (1) using the axis.

[0016]

[Equation 1]

In the present invention, the type of dimples formed on the surface of the ball is one or more types having different diameters and / or depths, preferably about 1 to 3 types. Further, the size of one dimple is not particularly limited, and if the dimple is made small, the number of dimples naturally increases to satisfy the total dimple volume ratio V _R, and if the dimple is made large. Although the number of dimples decreases, it is usually preferable that the dimples have a diameter of about 2 to 5 mm and a depth of about 0.07 to 0.30 mm. The total B of the dimple volumes is 244 to 61.
0 mm ^3, in particular to become what is preferred 325～447Mm ³ about, also total number of dimples is 250 to 600 pieces, it is particularly preferable to a 350 to 500 pieces.

In the golf ball of the present invention, the total dimple volume ratio V _R thus obtained exceeds 0.6%,
And is intended to design the dimple to be less than 1.5%, preferably those V _R is designed 0.8 to 1%, more preferably the dimples so that 0.85 to 0.95% Is. As a result, turbulent flow can be effectively generated around the ball during flight of the golf ball, air resistance can be reduced, and lift caused by backspin of the golf ball can be optimized to improve the flight distance of the golf ball. In this case, in the present invention, the total dimple volume ratio V _R is set to the above value, and there is no great circle on the ball surface that does not intersect the dimples. By arranging the dimples in the above, the aerodynamic symmetry described above is improved, and the flight distance and the symmetry are simultaneously improved.

Here, the arrangement of the dimples may be any arrangement as long as the great circles on which the dimples do not intersect are not formed on the ball surface as described above, and the ball surface is a regular octahedron or regular dodecahedron. , A regular icosahedron or the like can be used for division, and dimples can be evenly arranged in each of the divided areas. In the present invention, the ball surface is particularly 72 virtual spherical triangles and 6 virtual spherical surfaces. It is preferable that the dimples are arranged so as to be divided into equilateral quadrangles and have the same dimple arrangement in each of the virtual spherical triangles and the same dimple arrangement in each of the phantom spherical equal triangles. The symmetry can be more surely improved, and in this case, the total of each side forming the 72 virtual spherical triangles and the 6 virtual spherical equilateral quadrangle. It is more preferable to arrange the dimples so that the same number of dimples intersect with each other, whereby the distance between the dimples becomes uniform over the entire ball, and a golf ball having extremely excellent aerodynamic symmetry can be obtained. Is.

Specifically, the arrangement shown in FIGS. 2 and 3 and FIG.
The sequence shown in and the sequence shown in FIG. 5 can be exemplified. That is, as shown in FIGS.
12 virtual spherical isosceles hexagons 4 that are congruent with each other and 6 virtual spherical isosceles tetragons 5 that are congruent with each other are surrounded by four virtual spherical isosceles hexagons 4 and The four sides of the spherical isosceles quadrangle 5 are drawn so as to be common to the individual sides of the four imaginary spherical isosceles hexagons 4 surrounding the phantom spherical isosceles quadrangle 5, and further, all the phantom spherical isosceles hexagons 4
By drawing three diagonal lines 6, 6 and 6, respectively, and dividing each virtual spherical equilateral hexagon 4 into six virtual spherical triangles 7 ... 7 (in the figure, only one virtual spherical hexagon has a diagonal line 6 ), The ball surface has 72 virtual spherical triangles 7
And six virtual spherical equilateral quadrilaterals 5 are divided, and the dimples are arranged so that each virtual spherical triangle 7 has the same dimple array and each virtual spherical equilateral quadrangle 5 has the same dimple array. It is a thing.

Further, in this case, as in the arrangements of FIGS. 2 and 3 and the arrangement of FIG. 4, the same number of dimples intersects each side forming each virtual spherical triangle 7 and each virtual spherical isosceles quadrangle 5 (see FIG. 2). , 3 is 4 and in FIG. 4 is 5), and the number of dimples intersecting each side is usually 3
It is preferable that the number is up to 5.

FIGS. 2 to 5 explain the method of dividing the ball surface, and the dimple arrangement is not limited to these arrangements, and each virtual spherical triangle 7 has the same dimple arrangement, and Each virtual spherical equilateral quadrangle 5
It suffices that the inside has the same dimple arrangement. The method of dividing the ball surface into the above-mentioned 12 virtual spherical equilateral hexagons 4 and 6 virtual spherical equilateral quadrangles 5 can be performed by the following method.

That is, as shown in FIG. 6, the ball surface is first divided into known octahedrons (in the figure, reference numeral 20 is a dividing line of the octahedron), and the obtained spherical octahedron is constructed. 21 are drawn from the vertices of the spherical regular triangles, and the virtual spherical isosceles quadrangle 5 is drawn in the direction of the apex angle on the midline 21 in each vertex region of the spherical regular octahedron. Furthermore, one side of this virtual spherical equilateral quadrangle 5 and the above-mentioned midline 2
By forming the virtual spherical isosceles hexagon 4 with 1, the ball surface can be divided into 12 virtual spherical isosceles hexagons 4 and 6 virtual spherical isosceles quadrilaterals 5.

The golf ball of the present invention has the dimples arranged as described above, and the structure and material of the ball are not particularly limited, and a solid golf ball such as a one-piece ball or a two-piece ball can be formed by using an ordinary material. It may be a ball or a thread-wound golf ball. Further, the size, weight and the like can be appropriately set according to the golf rules.

Further, as a manufacturing method, an ordinary method can be adopted. For example, in the case of a two-piece solid golf ball, a pair of semi-dimple forming projections are formed on the inner surface of a hemispherical cavity. The dies are separably joined to each other to form a spherical cavity having a large number of dimple forming projections formed on the inner peripheral surface thereof, and a core is placed and held in the central portion of the spherical cavity. The golf ball of the present invention can be produced by a method of supplying a cover molding material to a gap formed between the inner peripheral surface of the tee and molding a cover layer having a large number of dimples around the core. As described above, no great circle that does not intersect even one dimple exists on the surface of the ball. Therefore, it is formed on the mold dividing surface that exists in the conventional golf ball. Seam line (great circle not intersecting dimples) needs to perform molding without causing that.

As a method of molding such a golf ball, for example, as shown in FIG. 7, a plurality of molds that communicate with the cavity 9 are formed on the mating surfaces of the two mold halves 8a and 8b, respectively. The pin insertion grooves 10 and 10 are provided, and the dimple molding pins 11 and 11 are arranged in the pin insertion grooves 10 and 10 such that the tips of the dimple molding pins 11 and 11 project into the cavity 9. Cavity 9 at the tip
A method of forming a dimple forming convex portion on the parting line so that the seam line does not occur is preferably used. In FIG. 7, reference numeral 12 is a golf ball core, and 13 is a molded cover layer.

Further, when the golf ball of the present invention is manufactured by the method of FIG. 7, the dimple molding pin 1 is used.
1, 11 are arranged so that they can move forward and backward, and they are advanced into the cavity 9 of the mold, and the core 1 is formed by the dimple forming pins 11, 11.
2 is held in the center of the cavity 9, and in this state, the cover molding material is supplied to the gap formed between the core 12 and the inner peripheral surface of the cavity 9 immediately before the cover molding material is completely filled. Alternatively, the dimple forming pins 11 and 11 may be retracted to the dimple forming position (state shown) to form the dimples on the parting line of the mold.

The cavity of the mold for molding the golf ball of the present invention does not have any great circle on the inner peripheral surface thereof which does not intersect with the dimple forming convex portion, but a further obtained golf ball is obtained. When the volume of the phantom sphere is assumed to be Amm ³ and the total volume of the dimples in the entire ball is Bmm ³ , the ball volume is represented by (B / A) × 100. the ratio of the total volume of all the dimples to (total dimple volume ratio) V _R is, those golf ball comprising a 0.6% <V _R <1.5% was designed the dimple-forming protrusions so as to obtain Thus, the golf ball of the present invention having the above-mentioned dimple arrangement can be obtained.

[0029]

As described above, according to the present invention,
The following effects can be obtained. (1) The ratio of the total volume of the dimples to the volume of the entire ball can be optimized. (2) A ball having no great circle that does not intersect the dimple is obtained. (3) By improving the geometrical arrangement of dimples, a golf ball having a uniform distance between dimples can be obtained. (4) A ball without seam lines can be obtained by the dimple forming protrusions provided on the mold dividing surface. Therefore, it is possible to obtain a golf ball having an excellent flight distance and a stable flight performance with good symmetry, which does not cause a difference in the flight performance due to a difference in hitting location of the ball.

[0030]

EXAMPLES Next, the effects of the present invention will be specifically shown by Examples and Comparative Examples, but the present invention is not limited to the following Examples.

A large size two-piece solid golf ball having the dimple arrangement shown in FIGS. 2 and 3 was manufactured using the molding die shown in FIG. This golf ball has 380 dimples and a dimple diameter of 3.8.
mm (1 kind), a V _R value 0.92%.

Assuming that the great circle corresponding to the dividing surface of the mold of this golf ball is a seam line, as shown in FIG.
The pole strike shown in (B) (direction of arrow f in (A)) and the seam strike (direction of arrow i in (B)) are carried out to carry,
The run and total flight distance were measured. The results are shown in Table 1.
Also, as a comparison, a large size two-piece solid golf ball having dimple arrangements shown in FIGS. 9 and 10 made of the same material (with seam lines where dimples do not intersect, 392 dimples, dimple diameter 3.63 mm (1 Type) and V _R value of 0.92%). The results are also shown in Table 1. In the hitting test, a swing robot was used, and the hitting was repeated 10 times with a driver (No. 1 wood) at a head speed of 45 m / sec, and the average was taken as the measured value.

[0033]

[Table 1]

As shown in Table 1, it has been confirmed that the golf ball of the present invention has good symmetry and, at the same time, has a long flight distance and excellent flight performance.

[Brief description of drawings]

1A and 1B are explanatory views for obtaining a dimple volume in the present invention, in which FIG. 1A is a schematic perspective view and FIG. 1B is a schematic sectional view.

FIG. 2 is a dimple arrangement pattern diagram of a golf ball according to an embodiment of the present invention.

FIG. 3 is a dimple array pattern view of the golf ball seen from another angle.

FIG. 4 is a dimple arrangement pattern diagram of a golf ball according to another embodiment of the present invention.

FIG. 5 is a dimple arrangement pattern diagram of a golf ball according to another embodiment of the present invention.

FIG. 6 is an explanatory diagram illustrating a method of dividing the surface of a golf ball into 12 virtual spherical equilateral hexagons and 6 virtual spherical equilateral quadrangles.

FIG. 7 is a schematic sectional view showing an example of a mold for obtaining the golf ball of the present invention.

FIG. 8 is an explanatory diagram illustrating a hitting direction when a golf ball is shot, in which (A) shows a pole hit and (B) shows a seam hit.

FIG. 9 is a dimple arrangement pattern diagram of a golf ball according to a comparative example.

FIG. 10 is a dimple array pattern view of the golf ball seen from another angle.

[Explanation of symbols]

 1 Dimple 4 Virtual spherical equilateral hexagon 5 Virtual spherical equilateral quadrilateral 6 Diagonal line 7 Virtual spherical triangle 8a, 8b Half mold 9 Cavity 10 Pin insertion groove 11 Dimple molding pin 12 Core 13 Cover layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Michio Inoue 20 Onohara, Chichibu City, Saitama Prefecture, within Bridgestone Sports Co., Ltd. (72) Inventor Hiroshi Masutani 20, Onohara, Chichibu City, Saitama Prefecture, within Bridgestone Sports Co., Ltd.

Claims (5)

[Claims] 1. A great circle that does not intersect with dimples on the surface is 1
A golf ball present does not exist, and Amm ³ the volume of the virtual sphere on the assumption that no dimples on the spherical surface of the ball, and Bmm ³ the sum in the entire golf ball dimple volume provided on the surface of the ball the ratio V _R of the total volume of all the dimples to the ball volume indicated when in (B / a) × 100 is, 0.6% <V _R <
A golf ball having a content of 1.5%. 2. A ball surface is provided with 12 congruent virtual spherical isosceles hexagons and 6 congruent virtual spherical isosceles quadrilaterals, each virtual spherical isosceles quadrilateral being surrounded by four virtual spherical isosceles hexagons, and The four sides of each virtual spherical isosceles quadrangle are drawn so as to be in common with the individual sides of the four virtual spherical isosceles hexagons that surround the hypothetical spherical isosceles quadrangle. Draw and evenly divide each virtual spherical isosceles hexagon into six virtual spherical triangles to divide the ball surface into 72 virtual spherical triangles and six virtual spherical equilateral quadrilaterals. 2. The golf ball according to claim 1, wherein the dimples are arranged on the surface of the ball so that the dimples are arranged in the same manner, and the insides of the virtual spherical isosceles squares are arranged in the same dimple. 3. The golf ball according to claim 2, wherein the same number of dimples intersect on all sides forming 72 virtual spherical triangles and 6 virtual spherical equilateral quadrangles. 4. A spherical shape having a large number of dimple forming protrusions formed on the inner surface of a hemispherical cavity by separably joining a pair of dies having a large number of dimple forming protrusions formed on the inner surface thereof. While forming the cavity, the core is placed and held in the center of the spherical cavity, and the cover molding material is supplied to the gap formed between the core and the inner peripheral surface of the cavity to form a large number of dimples. In a method for manufacturing a golf ball, which comprises molding a cover layer around a core, a plurality of pin insertion grooves communicating with the cavity are provided on the mating surfaces of the two mold halves, and the dimple molding pin is formed in the pin insertion groove. Is arranged so that the tip portion protrudes into the cavity, and a dimple forming convex portion is formed on the parting line of the cavity at the tip portion of the dimple forming pin,
A cavity having no great circle on the inner peripheral surface thereof that does not intersect with the dimple forming protrusion,
4. A method for manufacturing a golf ball, which comprises manufacturing the golf ball according to any one of 3 above. 5. A dimple forming pin is arranged so as to be able to advance and retreat, and is advanced into the cavity of the mold to hold the core at the center of the cavity with the dimple forming pin. In this state, inside the core and the cavity The cover molding material is supplied to the gap formed between the peripheral surface and the cover, and the dimple molding pin is retracted to the dimple forming position immediately before the cover molding material is completely filled, so that it is on the parting line of the mold. The golf ball manufacturing method according to claim 4, wherein the dimples are formed.