JPH06339550A - Manufacture of golf club head - Google Patents

Abstract

PURPOSE:To facilitate the manufacture with limited variations in products and with a better head balance by enabling the use of long carbon fibers to achieve a strength even with a less thickness, complete integration of inner and outer shells and a larger size with a light weight. CONSTITUTION:A cup-shaped core 1 is molded in such a manner that it will not be deformed under pressurization in the molding of a synthetic head body in which a recess and a protrusion for positioning the position of the core are formed with first top and bottom dies. The core 1 in which an open surface of a hollow part is covered with a lid 1A made of a synthetic resin is positioned in the a second bottom die 200 utilizing the recess and protrusion and SMC 10 is fed into the second top and bottom dies 7 and 200 to cover the core 1 with the head body. A pin insertion hole 5 for inserting a shaft is formed in a head body while being formed in the core 1 and the lid 1A or formed in the head body alone.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a golf club head, which is suitable for manufacturing a so-called carbon head.

[0002]

2. Description of the Related Art A conventional method for manufacturing a golf club head using a carbon fiber reinforced plastic (CFRP) material is, as shown in FIG. The plastic material in which carbon fibers are mixed is injected into the injection mold from an injection molding machine and is molded by being inserted in a predetermined position in the injection mold. What is molded by the injection mold is a semi-finished head 101 having a hollow interior without a sole portion integrally molded with the face plate 100. The sole plate 102 is manufactured separately, and the sole plate 10 is attached to the semi-finished head 101 having a bottom.
The golf club head was completed by attaching 2 using screws or adhesives or by welding. Sole plate 102
Is a metal such as an aluminum alloy, or a metal attached to a plastic material. The hollow portion 103 is located behind the face plate 100 and is provided with reinforcing ribs 1.
04 is formed.

A method of manufacturing a head by heating and pressing a plastic material without using injection molding is disclosed in JP-A-59-59.
The one described in Japanese Patent No. 2768 is known. this is,
The hollow metal core forming the inner shell of the head is placed in the cavity of the mold having the outer peripheral shape of the head together with the FRP molding material forming the outer shell of the head and heated and pressed to form the inner shell made of metal and the FRP. A head having a composite outer shell layer structure with an outer shell is manufactured. When using a light metal alloy with a thin wall thickness to reduce the weight of the metal core, the metal core may be deformed by the mold clamping pressure.To prevent this, a high pressure liquid is injected into the hollow part of the metal core during pressurization. A means such as pressurizing from the core portion side or forming a metal core obtained by forming a hole in a core member such as foamed plastic by coating is adopted. In addition, the positioning of the metal core in the molding die is performed by penetrating the rod-shaped jig that forms the club shaft axis part, attaching a protector to this rod-shaped jig, and closing the split die when the split die is closed. And the protective body are sandwiched by split molds.

[0004]

In the conventional injection-molded article, the length of the carbon fiber to be mixed in the plastic material is limited, and the short fiber is used for uniform mixing. Further, even when carbon of short fibers is mixed, the amount of mixing becomes partially uneven while the short fibers are spread into the cavity of the mold due to the injection pressure. Therefore, the semi-finished head 101 formed integrally with the face plate 100 has a large thickness, especially the face plate 1
Since the strength is weakened when the peripheral portion including 00 is thinned, a considerable thickness is required to secure sufficient strength. If the thickness of the head 101 of this semi-finished product becomes thick, the weight of the head also increases, and if the head is made large, the head becomes too heavy and it becomes difficult for a general golfer to shake it off. It was

[0005] than those described in JP-A-59-2768, increases inevitably the weight for using metal core is, an increase in the size of the head itself were those not be sufficiently achieved. Further, in order to reduce the weight of the metal core as much as possible, it is necessary to reduce the thickness of the metal core, which may cause deformation of the metal core due to the mold clamping pressure. To prevent this, the number of man-hours such as filling the inside of the metal core with a liquid or a low-melting metal or coating the core member of foamed plastic with the metal core was unavoidable, and it was a troublesome work. . In addition, positioning of the prepreg attached or pasted on the surface of the metal core is performed by positioning the tip of the rod-shaped jig that forms the club shaft axis and the protector mounting base that protects the periphery of the neck base of the head body. The split mold is closed and pressure is applied because the metal core on the toe side of the head is uneven in the amount of prepreg attachment or the mold clamping pressure is partially different. At times, there was a possibility that the rod-shaped jig would rotate around the axis of the rod-shaped jig, resulting in positional displacement. If the toe side of the metal core is displaced, the thickness of the outer shell of the head will be different from the designed shape.For example, even if it is designed to have a uniform thickness, a thin portion and a thick portion will be formed. However, the head balance is poor, and the manufactured heads vary in performance. Further, in this conventional example, since only the rod-shaped jig is passed through the metal core, in addition to the displacement due to the rotation around the axis as described above, the displacement in the axial direction is likely to occur. Further, when the plastic material is molded on the outer peripheral surface of the metal material, the metal material cools faster than the plastic material after heating and pressurizing the plastic material, which causes sink marks in the plastic material. Therefore, the outer shell of the FRP may not be completely integrated with the metal core, and the outer shell after molding may be defective in molding.

Therefore, according to the present invention, long carbon fibers can be used, the strength is strong even when the wall thickness is thin, the inner shell and the outer shell are completely integrated, the weight and size can be increased, and the head balance is good. An object of the present invention is to provide a method for manufacturing a golf club head, which has less variation and is easy to manufacture.

[0007]

In order to achieve the above-mentioned object, the present invention provides a first upper die having at least a convex portion for forming a hollow portion inside a core, and at least one of a concave portion and a convex portion. And a protrusion for forming a part of a pin insertion hole that serves as a passage for the shaft pin is formed in the core, or a recess for shaft insertion into which the protrusion formed in the convex portion of the first upper die is inserted. (1) A step of putting a synthetic resin material into a lower mold, clamping the mold, heating and pressurizing it to form a bowl-shaped core that is not deformed by the pressure applied when the head body is molded, and taking out this core from the first upper and lower molds. Process to form a lid with an open path for the shaft pin on the open surface of the hollow part of the core, and to expose at least the protrusions and recesses for core positioning of the core with the lid exposed to the outer periphery of the core. Molding sheet molding compound And the step of attaching the head main body according to the shape of the head main body, and the core positioning protrusions and recesses formed in the core are set in the recesses and protrusions corresponding to these protrusions and recesses formed in the second lower mold. A second upper mold and a second lower mold that are provided with a shaft pin that is inserted into a shaft mounting assumed position formed in the core, the lid, and the sheet molding compound, and the shaft pin is provided along the operation direction of the mold. A mold is clamped, the head body is molded by heating and pressurizing the shaft pin while the shaft pin is inserted, and a pin insertion hole for inserting the shaft is formed in the head body, the lid, and the core. .

[0008]

According to the present invention, a bowl-shaped hard core is first formed of a synthetic resin material, a synthetic resin lid is formed on the upper surface of the core, and then the convex portions and concave portions formed on the core are first formed. (2) The core is positioned and fixed in the second lower mold by setting it in the concave or convex portion of the lower mold, or by further inserting the shaft pin. The core in the second lower mold is not positioned only by the shaft pin, and it is sufficiently light without having to be thin enough to be deformed by the mold clamping pressure in order to achieve weight reduction like a metal core. Therefore, the core is not displaced or deformed when being pressed. Since the SMC is attached to this core and heated and pressed, the head body molded from the SMC has sufficient strength even if the wall thickness is thin, and there is no displacement or deformation of the core, so the head body is as thick as designed. Is molded into. Further, since the core, the lid, and the SMC after molding are synthetic resin materials, they are completely integrated. As a result, a lightweight and large head can be manufactured, the head balance is good, and product variations do not occur.

[0009]

The preferred embodiments of the present invention will be described below.

In FIG. 1, reference numeral 1 denotes a hard core 1 molded of a synthetic resin material, which is taken out from a first lower mold 2. The first upper mold 3 is provided with a concave portion 31 for forming a rib 13 extending from an upper portion of the back surface of the striking portion 11 to the sole portion 12, and a hollow portion 16 on both sides of the rib 13.
Is provided with a convex portion 32 (see FIG. 2).
When the upper mold 3 and the lower mold 2 are closed, this convex portion 32 is inserted into the first lower mold 2. The first lower mold 2 has a concave portion 21 for accommodating an insert member constituting the striking portion 11, a convex portion 22 for forming a concave portion 17 for mounting a sole plate (not shown), and a recess or protrusion 23 for shaft insertion. Is equipped with. In the case of the shaft insertion recess 23, a protrusion (not shown) to be inserted into the recess 23 is formed in the convex portion 32 of the first upper mold 3. In the case of the shaft insertion protrusion 23, a protrusion (not shown) to be inserted into this recess 23 is formed in the convex portion 32 of the first upper mold 3. In the case of the shaft insertion projection 23, the top surface of this projection 23 is set in contact with or in close proximity to the convex portion 32 of the first upper mold 3.
The cavity including the recess 21 has a replaceable mounting piece 21A.
The cavity including the convex portion 22 is also constituted by a replaceable piece 22A. Therefore, the mounting piece 21A corresponding to the shape and size of the striking portion 11 is first
The various striking parts 11 can be easily insert-molded by simply inserting them into the lower die 2 at predetermined positions. In addition, the placement piece 22A can also be adapted to the type of sole plate to be attached by aligning the projections 22 of various sizes. Further, a convex portion (not shown) for forming the weight adjusting boss 14 and a sole plate fixing boss 15 are provided on the bottom of the first lower mold 2.
It is possible to freely provide a convex portion (not shown) for forming the ridge and other irregularities for forming other necessary protrusions and depressions.

Either the concave portion or the convex portion formed on the first lower mold 2 may be either one. For example, the convex portion 22 for forming the mounting concave portion 17 of the sole plate is not formed, and the head body 6 is formed. It is also possible to form a portion for mounting the sole plate at the time of molding, or to form the striking portion 11 at the time of molding the head body 6 without forming the accommodating concave portion 21 of the insert member constituting the striking portion 11. Is also possible. In short, in order to position the core 1 in the second lower mold 200, which will be described later, at least a concave portion or a convex portion that forms a convex portion in the core 1 may be provided, and in the embodiment, a constituent member that forms a head. Part or all of (the striking part 11,
Sole plate, hole for shaft insertion, fixing boss 15
Etc.) was used to form the concave and convex portions,
Depending on the case, the concave portions or the convex portions may be simply formed instead of forming these constituent members.

The first upper and lower molds 3, 3 having the above structure
A synthetic resin material is charged in 2, and both molds 3 and 2 are closed and heated and pressed to form the hollow portion 16 and the core 1 having various irregularities. As an insert member for forming the striking surface 11, an arbitrary carbon fiber woven fabric is impregnated with a resin, wf
(Fiber content by weight) Those adjusted to 40 to 75% (prepreg) are preferable. If wf <40%,
Only the resin flows during molding, resulting in poor appearance and wf> 7
In the case of 5%, there was a defect that a portion not impregnated with the resin was generated, resulting in poor appearance and low impact resistance. Also,
It is also possible to form various patterns by changing the fiber fabric. For forming the core 1, for example, SM
C (sheet molding compound) up and down mold 3,
2 can be put into the cavity (excluding the concave portion 21 into which the prepreg serving as the striking portion 11 is inserted) and heat-pressed, which contains carbon fiber adjusted to wf 25-60%. preferable. The fiber length and the number of fiber bundles of carbon fibers can be arbitrarily selected.
The positions where these prepregs and SMC are used are arbitrary,
The appearance (pattern) of the head body 6 can be freely designed by selecting these use positions. The SMC mentioned here is a sheet-shaped molding material composed of a thermosetting resin, a filler, and carbon fiber, and is charged to 60 to 90% of the mold surface by compression molding, and 120 to 160 ° C. and 20 to 300 kg / It is formed with a mold clamping pressure of mm ² and a curing time of about 2 to 5 minutes.

The mold temperature of the first upper and lower molds 3 and 2 is 120 to 1.
The temperature is set to 60 ° C., preferably 130 to 140 ° C., and the curing time (keep time) is about 2 to 5 minutes.

In this way, when the core 1 shown in FIGS. 1 and 4 is formed and taken out from the mold, the lid 1A is attached to the opening surface 16A of the hollow portion 16 of the core 1 by the synthetic resin as shown in FIG. Mold with material. The lid 1A may be separately molded and fitted to the core 1 to cover it, or may be attached to the core 1 by welding. A hole serving as a passage for the shaft pin 71 is formed in the lid 1A. Thereafter, as shown in FIG. 6, the synthetic resin material (SMC) 10 forming the head body 6 is attached to the outer peripheral surface of the core 1 so as to be wrapped, and the core 1 is set in the second lower mold 200. The second lower mold 200 has a cavity formed by the mounting piece 201A, like the first lower mold 2, and a convex portion 220 corresponding to the sole plate mounting concave portion 17 of the core 1 is formed on the mounting piece 220A. is there. Further, a recess or protrusion 230 similar to the shaft insertion recess or protrusion 23 of the first lower mold 2 is formed at the bottom of the cavity of the second lower mold 200. This second lower mold 200
Synthetic resin material (SMC) that covers core 1 in pairs
The second upper mold 7 for molding the head body 6 from
A shaft pin 71 is provided to be inserted into a place where the pin insertion hole 5 is to be formed. The second upper mold 7 and the second lower mold 200 are closed and heated and pressed to mold the head main body 6 that covers the core 1 (see FIG. 7). At this time, the sole plate mounting concave portion 17 (see FIG. 3) of the core 1 is fitted to the convex portion 220 of the second lower mold 200 for positioning, and the shaft pin 71 is also the portion where the pin insertion hole 5 is to be formed. Through which the head is inclined with respect to the shaft with high accuracy, and moreover, the front, rear, left, and right directions of the whole are uniquely determined, and the plate thickness of the product is kept constant. The shaft pin 71 of the second upper mold 7 is configured to coincide with the mold operating direction. In this way, the shaft pin 71 is in the vertical direction and is aligned with the operation direction of the second upper mold 7, so that the lie angle of the product is kept constant.

According to the above-mentioned embodiment, the following No.
I got a head of 1 wood (driver). Volume: 197 cm ³ Weight of molded product: 150 g Weight after attaching sole plate: 165 g Maximum head width: 77.8 mm Center of gravity depth (Z _G ): 29.3 mm Impact part wall thickness: 8 mm Constituting the outer circumference Minimum wall thickness …… 3.5mm Inertia moment (Ix) in left and right direction …… 19g ・ mm ・ se
c ²

The joint of the second upper and lower molds 7 and 200,
That is, the parting line is set on the side peripheral surface, which improves the appearance of the product.

In the second embodiment of the invention, as shown in FIGS. 8 and 9, the lid 1A of the core 1 and the shaft pin 71 on the core 1 are used.
This is provided on the head main body 6 without providing a site where the insertion is planned. That is, when the SMC 10 is attached to the core 1 and the lid 1A without forming the portion through which the shaft pin 71 is inserted in the core 1 and the lid 1A,
The shaft pin 71 is adapted to be inserted from the hosel, which is shaped as, toward the sole.

In each of the embodiments, the impact surface 11 (cross-hatched portion in FIGS. 4 and 5) into which the core 1 is inserted, the mounting recess 17 for the sole plate, and one of the two surfaces adjacent to this recess (FIGS. The cross-hatched portion 3) was exposed on the outer surface even after the head body 6 was molded. Further, the bottom surface of the second lower mold 200 is inclined so that the shaft pin 71 descends vertically from above, but the operating direction of the second lower mold 7 descends with a certain angle. There may be cases. In this case, the bottom surface of the second lower mold 200 may be horizontal.

The golf club head (wood) obtained by this manufacturing method is as shown in the following table.
In the table, W # 1 is the first wood with a club length of 43 inches,
W # 3 is 42-inch wood number 3, W # 4 is 41.5.
Inch wood # 4 and W # 5 are 41 inch wood # 5. The moment of inertia Ix is the moment of inertia in the horizontal direction as described above, Iy is the moment of inertia in the vertical direction, and the unit thereof is g · mm · sec ² .

[0020]

[Table 1]

A convex portion formed on the core 1 (for example, a striking portion 1)
1) and a recess (for example, for attaching a sole plate) are for positioning the core in the second lower mold 200. By setting the protrusions and recesses of the core 1 in the recesses and protrusions formed on the second lower mold 200,
The lower die 200 is positioned at a predetermined position. Further, the core 1 is harder than the conventional foam, and does not collapse or shift due to the mold clamping pressure.
Further, the head body 6 is molded around the core 1 while leaving the bottom surface of the core 1, but at this time, the plate thickness of the head body 6 may be remarkably thinner than the conventional one. If the thickness obtained by adding the thickness of the core 1 and the thickness of the head body 6 is equal to or greater than a predetermined thickness, the durability at the time of impact can be made sufficient, and the plate thickness of the crown portion is not enough to improve the strength. It is irrelevant and may be thin in order to achieve a low center of gravity.

[0022]

As described above, according to the present invention, the core which is not deformed by the pressure applied during the molding of the synthetic resin head body having the positioning projections and recesses is formed beforehand. Then, a synthetic resin lid is formed on the open surface of the hollow portion of the core, and the core with lid is positioned by setting the convex portion and the concave portion of the core in the concave portion and the convex portion of the second lower mold. 2 There is no possibility that the core will be displaced due to the clamping force of the upper and lower molds. Particularly, in the manufacturing method in which the shaft pin is also inserted through the core and the lid, the positional deviation of the core can be prevented reliably. Therefore, even if the head body is molded from the SMC around the core, the plate thickness of the head body is as designed. In addition, long carbon fibers can be used for the SMC, and a head body having sufficient strength can be formed even if the carbon fibers are thin. Therefore, after calculating the strength to withstand the impact at the time of impact,
By making the core and the head body thin, it is possible to mold a light and large head. A larger head expands the sweet area, and a lighter head improves swing-out and head speed. In addition, since it has a double structure of the core with a lid and the head body, and both are molded from a synthetic resin material, they are completely integrated, and even if the thickness of the head body is extremely thin, the strength is sufficient. It is possible to reduce the weight. Moreover, the lie angle of the head manufactured due to the presence of the shaft pin is accurate. In the head manufactured by this invention,
Since there is no variation in the plate thickness of the head main body, the balance as a head is good and the manufacturing variations are eliminated.

[Brief description of drawings]

FIG. 1 is a perspective view showing a state where a core is molded and taken out by a first upper and lower molds.

FIG. 2 is a bottom view of the first upper mold.

FIG. 3 is a plan view of a sole portion of a core.

FIG. 4 is a perspective view of a core.

FIG. 5 is a perspective view showing a state in which the core is covered.

FIG. 6 is a perspective view showing a preparatory step for molding a head body.

FIG. 7 is a cross-sectional view of the second upper and lower molds in a closed state.

FIG. 8 is a sectional view of the head.

FIG. 9 is a plan view showing a detailed inner surface of the sole portion by cutting out an upper portion from the line AA in FIG.

FIG. 10 is a sectional view showing a conventional example.

[Explanation of symbols]

 1 core 2 first lower mold 3 first upper mold 5 pin insertion hole 6 head body 7 second upper mold 10 SMC 11 striking part 16 hollow part 23 shaft insertion recess or protrusion 32 convex part 71 shaft pin 200 second lower mold

Claims (2)

[Claims] 1. A hollow portion (1) at least inside the core (1).
6) a first upper die (3) having a convex portion (32) and at least one of a concave portion or a convex portion, and a convex portion (32) of the first upper die (3) The shaft insertion recess (23) into which the formed protrusion is inserted, or the core (1) is formed with a protrusion (23) forming a part of the pin insertion hole (5) that serves as a passage for the shaft pin (71). A step of putting a synthetic resin material into the first lower mold (2), clamping the mold, heating and pressing the mold to form a bowl-shaped core (1) that is not deformed by the pressure applied during the molding of the head body (6); The core (1) was taken out from the first upper and lower molds (3, 2), and a portion serving as a passageway for the shaft pin (71) was opened in the opening surface (16A) of the hollow portion (16) of the core (1). Lid (1
A) molding step, and a head main body after molding at least a convex portion or a concave portion for core positioning of the core (1) having the lid (1A) molded to form a sheet molding compound on the outer periphery of the core (1). (6) A step of adhering according to the shape, and a convex portion or concave portion for core positioning formed on the core (1) and a concave portion corresponding to the convex portion or concave portion formed on the second lower mold (200). And a step of setting on the convex portion, a core (1), a lid (1A), and a shaft pin (71) that is inserted into a shaft mounting assumed position formed in the sheet molding compound.
Second upper mold (7) provided with 1) along the working direction of the mold
And the second lower mold (200) are clamped and the shaft pin (71) is inserted to heat and pressurize the head body (6), and the head body (6) and the lid (1).
Pin insertion hole (5) for shaft insertion in A) and core (1)
A method of manufacturing a golf club head, comprising: 2. A hollow part (1) at least inside the core (1).
6) A synthetic resin material is put into a first upper mold (3) having a convex portion (32) for forming a portion 6) and a first lower mold (2) having at least one of a concave portion and a convex portion. A step of forming a bowl-shaped core (1) which is not deformed by the pressure of the head body (6) when the head body (6) is clamped, and the core (1) is attached to the first upper and lower molds (3, 2). ), And molding the synthetic resin lid (1A) on the opening surface (16A) of the hollow part (16) of the core (1), and at least the core of the core (1) on which the lid (1A) is molded. A step of exposing a positioning convex part or a concave part and adhering a sheet molding compound to the outer periphery of the core (1) following the shape of the head body (6) after molding; and the core positioning formed on the core (1) The convex portions and concave portions for use with the convex portions and concave portions formed on the second lower mold (200) correspond to these convex portions and concave portions. The step of setting in the concave portion or the convex portion, and the shaft pin (71) which is inserted into the shaft mounting assumed position formed in the sheet molding compound covering the core (1), and the shaft pin (71) is in the operation direction of the mold. A second upper mold (7) and a second lower mold (200) provided along the mold are clamped, heated and pressed to mold the head body (6), and the head body (6) is used for inserting the shaft. And a step of forming the pin insertion hole (5) in (3).