JP2001187172A - Golf ball molding die and golf ball molded thereby - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a die for forming dimples formed in a corresponding positions on split faces of a die so as to be same as dimples formed in another area and a golf ball manufactured thereby. SOLUTION: Plural projections for dimple forming are equipped striding over the equator of the split face part of one or both of a two-split type die with cavity inside. The die is almost in an elliptic shape in which E>D, where D is the diameter at the base of the projection in the equator direction and E is the diameter orthogonally crossing the equator. The golf ball is manufactured by the die. Dimples on the equator after flash generated on the split face in molding is removed are in a substantially circular plan shape with the diameter almost equal to E.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seamless golf ball having uniform dimples on the equator and a mold for molding the golf ball.

[0002]

2. Description of the Related Art A large number of dimples having a circular planar shape are arranged on the surface of a golf ball for the purpose of improving the flight performance of a hit ball. By using techniques such as octahedral arrangement, random arrangement, and the like, the balls are almost evenly arranged on the surface of the ball including the dividing position (equator) of the molding die. A mold for molding such dimples on the ball surface will be described in detail below with reference to the drawings.

FIG. 4 is a perspective view of a mold for molding a golf ball, FIG. 5 is an enlarged partial side view of the mold, and FIG. 6 is a sectional view taken along line AA of FIG. In the figure, a mold 1 comprises a lower mold 2 and an upper mold 3 (FIG. 4 omits illustration of the upper mold, but is substantially the same as the lower mold 2), and has a cavity 4 inside. A circular projection on the inner wall of the cavity 4 for dimple molding
Many 5 are arranged. These protrusions 5 also extend over the entire circumference at the position of the mold dividing surface 6 corresponding to the equator of the cavity 4,
They are usually arranged intermittently (only partially shown in FIG. 4).

Referring to FIGS. 5 and 6, the dividing surface 6 of the mold 1 is
It consists of a portion 6 'extending on the equator of the cavity and a portion 6''which extends around the contour at the base of the projection 5 and around it. In some cases, the projection may be formed by equally dividing the projection on the division surface at the projection position. In that case, the division surface 6 is formed on the equator over the entire circumference.

As shown in FIG. 7 as a partial side view, a golf ball 11 formed by such a mold has a portion 12 corresponding to a mold dividing surface on a land portion corresponding to the portion 6 '. Extended portion 12 'and dimple 13 corresponding to portion 6''
Part 12 '' extending along the edge 14 of the
In 2 ′ and 12 ″, burrs 15 of the ball molding material are usually generated during molding. In the case of a ball formed by a mold having the above-described mold dividing surface all around the equator, a dimple
Dimple 13 at the position that divides 13 vertically (or north and south)
Burrs occur, including inside 13.

The burr 15 generated during the ball forming process as described above
Is removed by a polishing machine. In the case of the ball 11 shown in FIG. 7, the ball 11 is polished over the entire circumference with a width w covering the diameter D of the dimple. At the center of the width w where the polishing amount (depth) t is the largest, the dimple diameter D
Is reduced to D ′ as shown in FIGS. 8 and 9, and the planar shape changes to an elliptical shape. In the case of a type in which a burr is formed at a position where the dimple is bisected, it is troublesome to delete the burr in the dimple by using another means. , And the ellipse of the dimple still occurs due to the grinding thickness t.

[0007]

A golf ball in which elliptical dimples different from the circular dimples formed in other areas are arranged in a row on the equator is impaired in commercial value from an aesthetic point of view. Not only in terms of performance, but also when the ball flies while rotating along the equator,
In the case of flying while rotating in the direction perpendicular to the equator, the aerodynamic characteristics exerted by the dimples are different, so that the flight distance is changed and the uniformity of the performance of the ball is impaired. The present invention has been made in view of such problems,
An object of the present invention is to provide a golf ball molding die that forms uniform dimples, and a golf ball molded by the mold.

[0008]

The present invention has a spherical cavity inside, a large number of dimple forming projections having a circular planar shape on the inner wall surface of the cavity, and a dividing surface at a position corresponding to the equator of the cavity. In a two-part mold, one or both of the split molds are provided with a plurality of dimple-forming projections so as to straddle the equator, and the equatorial diameter at the base position of these projections is D; A golf ball molding die having a substantially elliptical shape with D> E, where E is a diameter in a direction perpendicular to the direction of the golf ball.

A split mold of a two-part mold having a spherical cavity therein, a large number of dimple forming projections having a circular planar shape on the inner wall surface of the cavity, and having a dividing surface at a position corresponding to the equator of the cavity. A plurality of dimple-forming projections are provided on one or both of the divided surface portions so as to straddle the equator, and the diameter in the equatorial direction at the base position of these projections is D, and the diameter in the direction perpendicular to the equator is E, and D A golf ball formed using a mold having a substantially elliptical shape of E, and a dimple on the equator obtained by polishing a burr generated on a divided surface portion at the time of molding has a substantially circular planar shape having a substantially diameter E. It is a golf ball characterized by having.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, it is preferable that the dimple-forming projections on the dividing surface are located around the equator.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 is a partial side view of a golf ball molding die showing one embodiment of the present invention. In FIG. 1, a mold 1 is of a two-part type composed of a lower mold 2 and an upper mold 3 as in FIGS. 4 to 6, and although not shown, has a spherical cavity inside and has an inner wall surface. A large number of projections having a substantially circular planar shape for molding the dimple are provided.

At the position corresponding to the equator (not shown) of the cavity, there are divided surfaces 21 of the lower die 2 and the upper die 3, and a plurality of dimple forming projections 22 are provided at the divided surface positions along the circumferential direction. . At the base, these projections 22 have a major axis D in the equatorial direction and a minor axis E in a direction orthogonal thereto, and have a substantially elliptical planar shape. The projection 22 has a half of the minor axis E fixed to the lower mold 2 or the upper mold 3 (indicated by a chain line), and the other half protrudes in a direction orthogonal to the equator (indicated by a solid line). In this way, the lower die or the upper die that receives the protruding portion of the projection 22 is provided with the groove 23 that forms a half portion having an elliptical planar shape. The dividing surface 21 is thereby formed by a part 21 ′ extending substantially in the equator of the cavity and a part 21 ″ extending along the protruding shape and the groove 23, bypassing the projection.

FIG. 2 is a partial side view of a golf ball formed by the mold of the present invention. In FIG. 2, the formed golf ball 24 has a dimple 25 on the equator O with a protrusion 22.
The mold is divided by the mold 21 (see FIG. 1).
A portion 27 ′ extending to the equator O landing portion corresponding to the dividing surface portion 21 ′ and a portion 27 ″ extending on the edge 26 of the dimple are provided with burrs 28, which are protrusions of the molding material when molding the cover of the ball. Occurs.

FIG. 3 is a partial side view of the golf ball shown in FIG. 2 in which a burr generated portion of the ball is polished. In FIG. 3, the width x substantially corresponding to the minor diameter E of the area where the burr 28 is generated, that is, the dimple where the dimple 25 is arranged.
When the area 29 is polished, the burr 28 is removed, and at the same time, the major axis D of the dimple is reduced to the minor axis E by the gauge reduction based on the polishing, so that the substantially circular dimple 30 having the diameter E is obtained. Is formed. In this case, the maximum polishing depth (at the approximate center of the width x) is expected to be 10 to 100 μm, preferably 25 to 60 μm. In this example, the maximum polishing depth was about 40 μm. In the polishing, although not shown, a rotary grindstone, endless abrasive paper, or the like can be used.

In polishing the area 29, the polishing amount of the width x portion is estimated, and the thickness is gradually reduced by the amount to be polished, for example, from the thickest portion at the center of the width x toward both ends of the portion 29. As described above, a mold can be formed in advance.
However, the polished portion does not need to be particularly overlaid. In this embodiment, the polishing portion 29 was not overlaid, and the ellipse was made circular by polishing. As described above, when the dimples are circularized by polishing, a reduction in the depth and / or volume of the dimples is generally unavoidable. However, such a reduction is anticipated in advance, and the polishing portion is not thickened (thickening is not performed). It is also possible to increase the depth and / or volume of the dimple located in the polishing portion.

[0016]

As described above, the golf ball molding die according to the present invention is a seamless type which is applied when dimples are uniformly and densely arranged on the ball surface, that is, on the equator. Also, for a two-part mold for molding a ball having dimples, a plurality of dimple-forming protrusions are provided on one or both of the divided surfaces so as to straddle the equator. When the diameter in the equatorial direction at the base position is D, and the diameter in the direction perpendicular to the equator is E, the lens has a substantially elliptical shape with D> E.

In the ball molded using this mold, elliptical dimples are formed on the divided surface by the elliptical projections. However, when removing undesired burrs generated on the elliptical dimple portion during molding, the ball is usually removed. Burrs are removed by polishing using a rotating grindstone or the like that is applied, and at the same time, the major axis D of the elliptical dimple is reduced to a diameter E substantially equal to the minor axis, and as a result, a circular dimple of substantially the diameter E is formed. It is formed.

As described above, since a circular dimple different from the conventional elliptical dimple is provided on the periphery of the position corresponding to the mold dividing surface of the golf ball, the golf ball has excellent aesthetic appearance, and at the same time, uniform performance. It may be advantageous.

[Brief description of the drawings]

FIG. 1 is a partial side view of a golf ball molding die according to an embodiment of the present invention.

FIG. 2 is a partial side view of the golf ball according to the present invention.

FIG. 3 is a partial side view of the golf ball shown in FIG. 2 in which a burr-generated portion of the ball is polished.

FIG. 4 is a perspective view of a conventional golf ball molding die.

FIG. 5 is an enlarged partial side view of the mold shown in FIG. 4;

FIG. 6 is a sectional view taken along line AA of FIG. 5;

FIG. 7 is a partial side view of the golf ball formed by the mold of FIG. 4;

FIG. 8 is a partial side view of the golf ball showing a state where a burr-generated portion of the ball shown in FIG. 7 is polished.

FIG. 9 is a sectional view of the dimple shown in FIG. 8;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mold 2 Lower mold 3 Upper mold 4 Cavity 22 Protrusion 27 Mold division surface part D Diameter in the equator direction at the base of the protrusion E Diameter in the direction orthogonal to the equator O Equator of golf ball

Claims (3)

[Claims] 1. A two-part mold having a spherical cavity therein, a plurality of dimple-forming projections having a circular planar shape on an inner wall surface of the cavity, and a dividing surface at a position corresponding to the equator of the cavity. One or both of the split molds are provided with a plurality of dimple-forming projections on the split surface so as to straddle the equator, and the diameter in the equatorial direction at the base of these projections is D, and the diameter in the direction perpendicular to the equator is E. A golf ball molding die having a substantially elliptical shape of D> E. 2. The golf ball molding die according to claim 1, wherein the dimple-forming projections on the divided surface are located around the equator. 3. A split mold of a two-part mold having a spherical cavity therein, a large number of dimple-forming projections having a circular planar shape on the inner wall surface of the cavity, and a dividing surface at a position corresponding to the equator of the cavity. Either one or both of the divided surface portions are provided with a plurality of dimple-forming protrusions so as to straddle the equator, and the diameter in the equator direction at the base position of these protrusions is D, and the diameter in the direction perpendicular to the equator is E.
A golf ball formed using a mold having a substantially elliptical shape of D> E, and a dimple on the equator, which is obtained by polishing a burr generated on a divided surface portion at the time of molding, has a substantially circular planar shape having a substantially diameter E. A golf ball comprising: