JP2569657B2 - Mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a mold used for manufacturing a golf ball such as a two-piece golf ball.
The present invention relates to improvement of a mold obtained by a plastic working method (a cold pressing method).

[Problems to be solved by conventional technology and invention]

A golf ball such as a two-piece golf ball is usually manufactured using two upper and lower molds each having a hemispherical cavity having a convex portion for dimples, and these molds are generally used several times from a prototype master. It is manufactured by a precision casting method by inversion processing or a plastic processing method by one inversion of a prototype master.

That is, in the precision casting method, first, a silicon rubber inversion mold (female mold) is formed by transferring from a master mold (male mold) made of aluminum, brass, or the like having dimple-shaped depressions by machining, and then forming the silicon inversion mold. After injecting a ceramic slurry into a mold, drying and solidifying or firing to produce a ceramic mold (male mold), a molten metal for forming a mold is poured around the ceramic mold and cooled and solidified over a long time. Finally, this is a method of obtaining a mold by breaking the ceramic mold.

In addition, as a plastic working method, a cemented carbide master (male) in which a dimple-shaped recess is formed in a semi-spherical concave portion without a dimple convex portion of a preforming die is press-fitted at a high pressure and dimples are formed in a plastic deformation region. A method of transferring a shape to obtain a mold (hereinafter, referred to as a first plastic working method) is generally widely used.

The above-mentioned precision casting method uses a material with good castability such as alloy tool steel or beryllium copper alloy as a metal for molding. Means the edge of the dimple portion on the mold surface), but the accuracy is reduced each time because there are three inversions, the sphericity and the dimple accuracy are inferior. There are drawbacks such as requiring equipment, time required for mold production, and high production cost.

The first plastic working method uses a material that is easily plastically deformed, such as a zinc-based alloy, as the metal of the preforming mold. However, the mold according to this method has a high degree of accuracy because the inversion is performed once, With good sphericity and good dimple accuracy,
The mold material is soft and easy to process, and the mold can be manufactured in a short time with small-scale equipment and the cost is low. On the other hand, the mold material is soft and the durability is very poor. There is a disadvantage that.

On the other hand, as a plastic working method capable of solving the drawbacks of the first plastic working method, as shown in FIG. 2, a dimple-shaped recess is formed in a hemispherical cup-shaped shell a made of a material having good rollability such as stainless steel. A dimple shape is transferred using a cemented carbide prototype master (male type), and the shell a is inserted into the hemispherical concave portion c of the holder b to obtain a mold (hereinafter referred to as plastic working second method). Has been proposed (US Pat. No. 3,543,380).

In the second plastic working method, since a relatively hard metal such as stainless steel can be used as the material of the mold, the durability can be improved as compared with the mold of the first method. In addition, the mold can be manufactured in a short time with small-scale equipment, and the cost is low. However, in the mold manufactured by the second plastic working method, a gap e is formed between the holder b and the dimple projection d of the shell a as shown in FIG.
Therefore, thermal conductivity from the holder b to the shell a is poor,
There is a new problem that the shell a cannot be efficiently heated during ball production. Moreover, since the molding of the shell is plastically deformed in a short time by using a pressing method or a pneumatic method, a molding method using a viscous material, such as an explosive pressure method, residual stress exists in the shell a, and therefore, As the use of the mold is repeated, the projections f are deformed into a gentle shape different from the initial shape, and there is a problem in durability.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a mold having improved heat conductivity and durability to a shell in the mold according to the second plastic working method described above.

[Means and actions for solving the problems]

That is, in order to achieve the above object, the present invention has a hemispherical cup-shaped shell in which a number of protrusions corresponding to the dimples of the golf ball are formed to bulge inward on the peripheral wall portion, and is fitted into the hemispherical concave portion of the holder. In a mold in which a golf ball is molded by filling a molding material into the cup-shaped shell, the cup-shaped shell is fitted to the holder such that a flat portion of the shell comes into contact with a hemispherical wall surface of the holder. In addition, each of the protrusions of the shell is filled with a heat conductive substance.

The mold of the present invention is characterized in that a gap between the cup-shaped shell and the hemispherical concave wall surface of the holder generated when the cup-shaped shell is fitted to the holder such that the flat portion of the cup-shaped shell comes into contact with the hemispherical wall surface of the holder. That is, since the space inside the bulging projection of the cup-shaped shell is filled with the heat conductive material, the heat of the holder is transmitted to the shell via the heat conductive material, and thus the shell is efficiently heated. Can be. In addition, the heat conductive material serves as a support for the projections of the shell, so that there is no inconvenience that the projections are deformed by residual stress.

 Hereinafter, the present invention will be described in more detail.

As described above, the mold of the present invention fits the cup-shaped shell into the holder so that the flat portion of the shell comes into contact with the hemispherical wall surface of the holder, and a heat-conductive substance in each projection of the shell. It is filled.

In this case, the holder is preferably made of a material such as steel or copper alloy, and the cup-shaped shell is preferably made of a material such as steel or copper alloy.

Further, as the heat conductive substance, it is preferable to use a substance having high thermal conductivity and high hardness as much as possible, whereby the improvement of the heating efficiency of the shell and the prevention of deformation of the projection of the shell can be reliably achieved. . Specifically, various metals, silver brazes, inorganic adhesives, and the like can be suitably used as such a heat conductive substance.

In addition, although there is no limitation in the method of manufacturing the mold of the present invention,
For example, a method in which a plurality of concave portions corresponding to the above-mentioned protrusions on the outer periphery of the shell on which the protrusions are previously formed by appropriate means are filled with a heat conductive substance and the shell is fitted into a hemispherical concave portion of the holder can be suitably adopted.

Next, the present invention will be described in detail with reference to examples, but the present invention is not limited to the following examples.

〔Example〕

FIG. 1 shows a mold according to an embodiment of the present invention.

In this mold 1, reference numeral 2 denotes a lower mold holder. The holder 2 has a hemispherical concave portion 4 having a diameter slightly larger than the diameter of a golf ball formed at the center of the upper surface of a square pillar-shaped metal base 3. . In the figure, reference numeral 5 denotes a hemispherical cup-shaped metal shell fitted into the hemispherical concave portion 4 of the holder 2. A number of projections 6 corresponding to the dimples of the golf ball are provided on the peripheral wall of the shell 5. The bulge is formed. The shell 5 is fitted in the concave portion 4 such that the flat portion contacts the wall surface 7 of the concave portion 4, and a zirconia-based inorganic adhesive such as a zirconia-based And a low melting point metal such as silver solder. In addition, a ring-shaped flange portion 10 that covers the PL surface (upper / lower die mating surface) 9 is integrally protruded from an outer edge of the opening of the shell 5.

The mold 1 of this embodiment has a large number of protrusions 6 corresponding to the protrusions 6 on the outer peripheral surface of the shell 5 in which a large number of protrusions 6 corresponding to the dimples are formed in advance by appropriate means such as a pressing method, a pneumatic method, and an explosion pressure method. The concave portion is filled with the heat conductive material 8, and the shell 5 is fitted and fixed in the concave portion 4 using the heat conductive material 8 as an adhesive or another adhesive. The flat portion of the outer peripheral surface of the shell 5 is in contact with or adhered to the wall surface of the concave portion 4 of the holder 2.

In the case of manufacturing a golf ball using the mold 1 of Example 1, the core ball is covered with a pair of half-shell-shaped cover materials without dimples, and this is compression-molded with a mold, and the cover material is thermally fused. And a compression molding method for forming dimples or an injection molding method for holding a core ball in a mold with a support pin and injecting a cover material around the core ball to form a cover. Also transfers heat from the holder 2 to the shell 5, but in the mold 1, the space between the peripheral wall of the recess 4 of the holder 2 and the protrusion 6 of the shell 5 is filled with a heat conductive substance 8. Therefore, heat transfer from the holder 2 to the shell 5 is efficiently performed. In addition, the heat conductive material 8 acts as a support for the projections 6, so that even when the mold 1 is used for a long time, the projections 6 are hardly deformed, and the durability is good.

Effect of the Invention As described above, the mold of the present invention has excellent heat conductivity from the holder to the shell, so that a golf ball can be manufactured with high productivity, durability is excellent, and deformation of the projection of the shell is small. Since it is unlikely to occur, a golf ball with good dimple accuracy can be manufactured for a long period of time.

[Brief description of the drawings]

FIG. 1 is an end view showing an embodiment of the present invention, and FIG. 2 is an end view showing an example of a conventional golf ball mold. 1 ... mold, 2 ... holder, 4 ... hemispherical recess, 5 ...
... Shell, 6 ... Protrusion, 7 ... Wall surface, 8 ... Heat conductive material.

Claims (1)

(57) [Claims] 1. A hemispherical cup-shaped shell in which a number of projections corresponding to dimples of a golf ball are bulged inward on a peripheral wall portion, fitted in a hemispherical concave portion of a holder, and molded into the cup-shaped shell. In a mold filled with a material to mold a golf ball, the cup-shaped shell is fitted to the holder such that a flat portion of the shell is in contact with a hemispherical wall surface of the holder, and each projection of the shell is provided. A mold for a golf ball, characterized by being filled with a heat conductive material.