JPH01166912A - Mold - Google Patents

Abstract

PURPOSE:To improve the heat conductivity from a holder to a shell and their durability by a method wherein heat conductive substance is filled in a gap, which is formed between the wall surface of the hemeispherical recess of the holder and the projections of the cup-shaped shell. CONSTITUTION:As heat conductive substance 8, metal such as silver solder or the like is filled in a gap, which is formed between the wall surface 7 of the hemispherical recess 4 of a holder 2 and the projections 6 of a shell 5. The heat of the holder is transferred through the heat conductive substance to the shell, resulting in allowing to efficiently heat the shell. Further, the heat conductive substance serves as the supports of the projections of the shell, resulting in preventing the trouble of the deformation of the projection due to residual stress from developing.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a mold used for manufacturing golf balls such as two-piece golf balls, and more specifically, a plastic working method (cold pressing method). Regarding the improvement of molds obtained by.

[Prior Art and Problems to be Solved by the Invention] Golf balls such as two-piece golf balls are usually manufactured using two upper and lower molds each forming a hemispherical cavity with a convex portion for a dimple. These molds are generally manufactured by a precision casting method by reversing the master mold several times or by a plastic working method by reversing the master mold once.

That is, in the precision casting method, first, a master mold (male mold) made of aluminum, brass, etc. with dimple-like depressions is transferred by machining to create an inverted mold (female mold) made of silicone rubber, and then this silicon inverted mold is transferred. After pouring ceramic slurry into a mold and drying and solidifying or firing it to produce a ceramic mold (male mold), molten metal to form the mold is poured around this ceramic mold and cooled over a long period of time. This method involves solidifying and finally destroying the ceramic mold to obtain a mold.

In addition, as a plastic processing method, a carbide metal prototype master (male mold) with a dimple-shaped recess is press-fitted under high pressure into a hemispherical recess without a dimple convex part of a preform mold, and the dimple is formed in the plastic deformation area. How to obtain a mold by transferring the shape (
(hereinafter referred to as the first plastic working method) is commonly used.

The precision casting method described above uses materials with good castability, such as alloy tool steel and beryllium copper alloy, as the mold metal, but the molds obtained by this precision casting method are strong and durable. (refers to the edge of the dimple part on the mold surface), but on the other hand, the accuracy decreases each time because it is inverted three times, resulting in poor sphericity and dimple accuracy, and large-scale casting and side manufacturing. The drawbacks are that it requires equipment, takes time to make the mold, and is expensive.

In addition, the first plastic working method uses a material that is easily plastically deformed, such as a zinc alloy, as the metal for the preforming mold, but the mold produced by this method has high accuracy because it is only inverted once. , sphericity and dimple precision are good,
The mold material is soft and easy to process, and the mold can be manufactured in a short time using small-scale equipment, and the cost is low. However, since the mold material is soft, it has very poor durability. There is a drawback.

On the other hand, as a plastic working method that can eliminate the drawbacks of the first plastic working method, as shown in Fig. 3, a hemispherical cup-shaped shell a made of a material with good malleability such as stainless steel
The dimple shape is transferred using a cemented carbide prototype master <m type) with dimple-shaped depressions on the surface, and
A method of obtaining a mold by fitting this shell a into a hemispherical recess C of a holder b (hereinafter referred to as the second plastic working method) has been proposed (US Pat. No. 3,543,380).

This second plastic working method uses a relatively hard metal such as stainless steel as the mold material, so it
In addition to being able to improve durability than the method mold, the first
Similar to the method, molds can be manufactured in a short time using small-scale equipment, and the cost is low. However, this plastic processing second
As shown in Figure 3, the mold manufactured by this method has a gap e between the holder b and the dimple protrusion d of the shell a, which results in poor thermal conductivity from the holder b to the shell a, making it difficult to manufacture balls. A new problem arises in that sometimes the shell a cannot be heated efficiently.

In addition, because the shell is plastically deformed in a short time using a molding method using a viscous material such as a pressing method, pneumatic method, or explosive pressure method, residual stress exists in shell a. As the mold is repeatedly used, the protrusion f deforms and takes on a gentle shape different from the initial shape, which also poses 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 using the second plastic working method described above, which has improved thermal conductivity to the shell and durability.

[Means and effects for solving the problems] That is, in order to achieve the above object, the present invention includes a hemispherical cup-shaped shell in which a number of protrusions corresponding to the dimples of a golf ball are bulged inward on the peripheral wall. In a mold that fits into a hemispherical recess of a holder and is configured to mold a golf ball by filling a molding material into the cup-shaped shell, the wall surface of the hemispherical recess of the holder and the cup-shaped shell are in contact with each other. The gap formed between the protrusion and the protrusion is filled with a thermally conductive material. .

In the mold of the present invention, the gap between the wall surface of the hemispherical recess of the holder and the protrusion of the cup-shaped shell is filled with a thermally conductive material, so that the heat of the holder is transferred to the shell through this thermally conductive material. Therefore, the shell can be heated efficiently. In addition, the thermally conductive material serves as a support for the protrusions of the shell, so that problems such as deformation of the protrusions due to residual stress do not occur.

The present invention will be explained in more detail below.

In the mold of the present invention, as described above, the gap formed between the wall surface of the hemispherical recess of the holder and the protrusion of the cup-shaped shell is filled with a thermally conductive substance.

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

In addition, it is preferable to use a thermally conductive material that has as high a thermal conductivity as possible and a high hardness, as this can reliably improve the heating efficiency of the shell and prevent the protrusions of the shell from deforming. . Such heat transfer 4
Specifically, various metals, silver solder, inorganic adhesives, etc. can be suitably used as the material.

Although there are no limitations to the method for manufacturing the mold of the present invention, for example, a number of recesses corresponding to the projections on the outer periphery of a shell in which projections have been formed in advance by an appropriate means are filled with a thermally conductive substance, and the shell is There is a method of fitting into the hemispherical recess of the holder, or a layer of thermally conductive material is laminated on the wall of the hemispherical recess of the holder, and a shell material with no protrusions is inserted into the recess, and then the material is inserted into the shell. By press-fitting the prototype master, a large number of projections corresponding to the dimples are formed on the shell in the plastic deformation region, and the thermally conductive material layer is deformed to fill the space between the recess wall surface and the projections with a thermally conductive material. method can be suitably employed.

EXAMPLES Next, the present invention will be specifically explained 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, 2 is a holder for the lower mold, and this holder 2 has a hemispherical recess 4 having a diameter slightly larger than the diameter of a golf ball at the center of the upper surface of a square columnar metal base 3.
was formed. In addition, 5 in the figure is the holder 2 mentioned above.
A hemispherical cup-shaped metal shell is fitted into a hemispherical recess 4, and a number of protrusions 6 corresponding to the dimples of a golf ball are bulged inward on the peripheral wall of the shell 5. Further, the gap formed between the wall surface 7 of the hemispherical recess 4 of the holder 2 and the protrusion 6 of the shell 5 is filled with a metal (such as silver solder) as a thermally conductive substance B.

Here, the mold 1 is made by laminating a metal layer on the entire wall surface of the recess 4 of the holder 2 by means of metal spraying, electroforming, etc., and then inserting a shell material in which no protrusions are formed into the recess 4. A carbide metal prototype master (male mold) with dimple-shaped recesses is press-fitted into this shell, and dimple-shaped protrusions 6 are formed in the shell material in the plastic deformation region, and the metal is press-fitted by the press-fitting of the master. It is manufactured by deforming the layer and filling the space between the wall surface of the recess 4 and the protrusion 6 with metal. Therefore, a hemispherical cup-shaped metal layer 9 is fixedly formed between the walls of the four parts 4 of the holder 2 and the shell 5, covering the entire surface of the walls.

[Embodiment 2] FIG. 2 shows another embodiment of the present invention. In the mold 11 of FIG. 2, the same reference numerals are given to the parts having the same structure as those of the mold of FIG. 1, and the explanation thereof will be omitted.

In the mold 11 of this embodiment, the thermally conductive material 8 is filled with an inorganic adhesive such as zirconia, or a low melting point metal such as silver solder. Further, on the outer edge of the opening of the shell 5, P
Ring-shaped flange 13 that covers the L surface (upper and lower mold mating surfaces) 12
are integrally protruded.

The mold 11 of this embodiment has a large number of protrusions 6 corresponding to the dimples formed on the outer circumferential surface of the shell 5, in which a large number of protrusions 6 corresponding to the dimples are formed in advance by an appropriate means such as a pressing method, a pneumatic method, or an explosive pressure method. The recess is filled with a thermally conductive substance 8, and the shell 5 is fitted and fixed into the recess 4 using the thermally conductive substance 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 recess 4 of the holder 2.

When manufacturing a golf ball using mold 1.11 of Examples 1 and 2 above, the core ball is covered with a pair of half-shell-shaped cover materials without dimples, and this is compression-molded in a mold to form the cover material. A compression molding method in which the core ball is heat-sealed and dimples are formed, or the core ball is held in a mold with support pins 1.
An injection molding method is used in which a cover is formed by injecting cover material around this core sphere. In either method, heat is transferred from the holder 2 to the shell 5, but the above-mentioned mold 1.11 In this case, a thermally conductive substance 8 is filled between the peripheral wall of the recess 4 of the holder 2 and the protrusion 6 of the shell 5, so that heat is efficiently transferred from the holder 2 to the shell 5. Further, the thermally conductive substance 8 acts as a support for the protrusions 6, so that even if the molds 1, 11 are used for a long period of time, the protrusions 6 are not easily deformed and have good durability.

As explained above, the mold of the present invention has excellent heat conductivity from the holder to the shell, and therefore can manufacture golf balls with high productivity. Since deformation is less likely to occur, golf balls with good dimple precision can be manufactured over a long period of time.

[Brief explanation of the drawing]

FIG. 1 is an end view showing one embodiment of the present invention, FIG. 2 is a side view showing another embodiment of the invention, and FIG. 3 is an end view showing an example of a conventional golf ball mold. be. ■...Mold, 2...Holder, 4...Semispherical recess, 5...Shell, 6...Protrusion, 7...Wall surface, 8...
...Thermal conductive material, 11... Mold.

Claims (1)

[Claims] 1. A hemispherical cup-shaped shell whose peripheral wall has a number of protrusions corresponding to the dimples of a golf ball bulging inward is fitted into the hemispherical recess of the holder, and the cup-shaped shell is filled with molding material. A mold for molding a golf ball, characterized in that a gap formed between the wall surface of the hemispherical recess of the holder and the protrusion of the cup-shaped shell is filled with a thermally conductive substance. A mold to be used.