JPH0583271B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field] The present invention is a method for manufacturing a golf club head, and relates to a method suitable for manufacturing a golf club head called a so-called carbon head. [Prior Art] The conventional method for manufacturing golf club heads using carbon fiber reinforced plastic (CFRP) material is to first foam a synthetic resin material in a foaming mold to form a rigid foam, and then to this foam. A sheet of sheet molding compound (SMC) is wrapped around the foam.
The product was wrapped in SMC and molded using a mold under pressure and heat. CFRP is a composite material in which resin is reinforced with carbon fibers, and SMC is a sheet-shaped molding material made of thermosetting resin, filler, and carbon fibers, and by compression molding, 60 to 90% of the mold surface is charged. At 120~160℃ and a clamping pressure of 20~300Kg/ ^mm2 ,
It is formed in a curing time of about 2 to 5 minutes. The foam is light and has a certain hardness, and is positioned within the mold. Since the positioned foam is generally urethane foam, it may partially collapse or shift position when mold clamping pressure is applied. In other words, a recess was formed in the bottom of the foam, and the protrusion formed on the mold was fitted into the recess for positioning, but the mold clamping pressure was extremely high, and the mold clamping pressure Because they are not used equally on all parts of the body, they may become partially crushed, or the parts that fit with the positioning protrusions may be damaged, resulting in misalignment. If the foam partially collapses or becomes misaligned, the area around the foam
SMC is not formed to the designed thickness at each part of the outer periphery of the foam. As a result, the thickness of the CFRP molded part varies. As a result, the amount of SMC used to calculate strength is increased based on the thinnest part of the plate. As the amount of SMC increases, the weight of the head also increases, so even if you try to make the head larger, it will become too heavy to swing. Furthermore, if the thickness of the head is not formed as designed, the balance will be poor and performance will vary from club to club. If uneven thickness of CFRP and changes in the design shape caused by misalignment of the foam can be prevented, the head can be made larger without increasing the weight, and a uniform head with good head balance can be manufactured, making it possible to create a uniform head for each club. Although variations in performance can be reduced, it has been difficult to increase the size of the head using the conventional manufacturing method of attaching SMC to a foam and heating it under pressure. In particular, with a wood-type head, the thickness of the parts other than the hosel and crown is closely related to the durability at impact, the weight of the head, the size of the sweet area, and the magnitude of the moment of inertia. It was important that it be molded into a shape. Another conventional example is the one described in Japanese Unexamined Patent Publication No. 59-2768. This is done by placing the hollow metal core that makes up the inner shell of the head into the cavity of a mold that has the shape of the outer periphery of the head, together with the FRP molding material that makes up the outer shell of the head, and heating and pressurizing it to form the inner shell made of metal. The head has a composite outer shell layer structure with an outer shell made of FRP. However, in this configuration, since a metal core is used, the weight inevitably increases, and the head itself cannot be sufficiently enlarged. Furthermore, if a light metal alloy with a thin wall thickness is used to reduce the weight of the metal core, the metal core may be deformed by mold clamping pressure. In order to prevent this, when pressurizing, liquid is injected at high pressure into the hollow part of the metal core to apply pressure from the core side, or the core material such as foamed plastic is covered with a metal core with holes. measures have been adopted. As described above, in this conventional example, if an attempt is made to increase the size of the head by using a metal core, the weight of the metal core will also increase. If you try to reduce the weight of the metal core as much as possible, the metal core will deform due to mold clamping pressure, so to prevent this, it is necessary to fill the metal core with liquid or low-melting metal, or to attach the metal core to a core material such as foamed plastic. This inevitably increases the number of man-hours such as forming a coating, and is also a troublesome work. In addition, the positioning within the mold of the Uripreg attached or affixed to the surface of the metal core is determined by the tip of the rod-shaped jig that forms the shaft of the clubshaft and the base for attaching the protector that protects the area around the base of the neck of the head body. Therefore, the metal core on the toe side of the head is not able to tighten the split mold to apply pressure due to uneven prepreg adhesion amount or local differences in mold clamping pressure. There was a risk that the rod-shaped jig would rotate around the axis when the rod-shaped jig was hung, causing misalignment. If the toe side of the metal core is misaligned, the wall thickness of the head outer shell will differ from the designed shape. For example, even if the design is intended to have a uniform wall thickness, thinner and thicker regions will be formed. , the head balance is poor, and performance varies depending on the manufactured head. Further, in this conventional technique, since the rod-shaped jig is simply passed through the metal core, in addition to the displacement due to the rotation of the rod-shaped jig around the axis as described above, axial displacement is also likely to occur.
Furthermore, since the metal core and FRP have different specific heats, it is difficult to completely integrate the two, and there is also the risk of poor adhesion or poor molding. [Purpose] This invention enables the thickness of the head body to be formed as designed. For example, in order to enlarge the head shape and expand the sweet area, the face and hosel can be removed while maintaining sufficient strength. It is necessary to make the part uniformly thin, but it is possible to mold such a uniform and thin board thickness, and since it is made of synthetic resin, the core and foam can be integrated after molding the head body, and is a golf club head that prevents the foam from collapsing or misaligning even if the foam is filled inside (at least at the crown contact area), has good head balance, has no product variations, and is easy to manufacture. The purpose is to provide a manufacturing method for. [Structure] In order to achieve the above object, the present invention includes a first upper mold having at least a convex portion for forming a hollow portion inside the core, and at least one of a concave portion or a convex portion, and Combined with the first lower mold, which has a recess for shaft insertion into which a protrusion formed on the convex part of the upper mold is inserted, or a protrusion formed in the core to form a part of the pin insertion hole that serves as a path for the shaft pin. A process of introducing a resin material, clamping the mold, applying heat and pressure to form a core that will not deform due to the pressure applied during molding of the head body, and taking out this core from the first upper and lower molds and placing it in the hollow part of the core. A process of foaming the resin material and filling the foam, a process of pasting the synthetic resin material that is the molding material for the head body so as to wrap around the core and the foam, and a process of attaching the protrusions and depressions formed in the core for core positioning. A process of setting the shaft pin into the concave part or convex part corresponding to the convex part or concave part formed on the second lower mold, and inserting the shaft pin into the expected shaft attachment position formed in the molding material of the core, foam, and head body. The shaft pin clamps the second upper mold and the second lower mold, which are provided along the operating direction of the mold, and molds the head body by applying heat and pressure. and forming a pin insertion hole for insertion. [Examples] Preferred embodiments of the present invention will be described below. FIG. 1 shows a first embodiment, in which a molded hard core 1 is indicated by the reference numeral 1, and is shown in a state taken out from a first lower mold 2. FIG. The first upper mold 3 has a striking part 1
Rib 13 extending from the upper part of the back side of 1 to the sole part 12
This rib 1 is provided with a recess 31 for forming a
Convex portions 32 for forming hollow portions 16 on both sides of 3
(See Figure 2). When the upper mold 3 and lower mold 2 are closed, this convex portion 32 is inserted into the first lower mold 2. The first lower mold 2, a concave portion 21 for housing the insert member constituting the striking portion 11, a convex portion 22 for forming a concave portion 17 for attaching a sole plate (not shown), and a recess or protrusion 23 for shaft insertion. We are prepared. Recess for shaft insertion 23
In this case, this depression 2 is formed on the convex part 32 of the first upper mold 3.
A protrusion (not shown) to be inserted into 3 is formed in advance. In the case of the shaft insertion protrusion 23, the top surface of the protrusion 23 should be in contact with or very close to the protrusion 32 of the first upper die 3. The cavity including the recess 21 is made up of a replaceable piece 21A, and the cavity including the protrusion 22 is also made up of a replaceable piece 22A. Therefore, various types of impact parts 11 can be easily insert-molded by simply inserting the placement pieces 21A corresponding to the shape and size of the impact parts 11 into predetermined positions of the first lower mold 2. Further, by arranging convex portions 22 of various sizes in the placement piece 22A, it can be adapted to the type of sole plate to be attached. Further, on the bottom of the first lower mold 2, there are a convex part (not shown) for forming the weight adjustment boss 14, a convex part (not shown) for forming the sole plate fixing boss 15, and other parts. Unevenness can be freely provided to form necessary protrusions and depressions. The first lower mold 2 has both of the core positioning convexity, the concave part for concave formation, and the convexity (the concavity 21 and the convexity 22) in the above-mentioned embodiment, but it may be either one of them. , for example, without forming the protrusion 22 for forming the recess 17 for attaching the sole plate,
When forming the head body 6, a part for attaching the sole plate can be formed, or a recess 21 for storing the insert member constituting the striking part 11 can be formed.
The striking part 11 is not formed when the head body 6 is formed.
It is also possible to insert mold. In short,
In order to position the core 1 on a second lower mold 200 (described later), it is sufficient that the core 1 is formed with at least a concave portion or a convex portion. 11, Sole plate, shaft insertion hole, fixing boss 15
etc.), and in some cases, the recesses and protrusions are used not for forming these component parts, but simply for forming core positioning protrusions and recesses. It may be formed in advance. A synthetic resin material is put into the first upper and lower molds 3 and 2 having such a configuration, and both molds 3 and 2 are closed and heated and pressurized to form a core 1 having a hollow portion 16 and various irregularities.
is formed. As an insert member for forming the striking surface 11, any carbon fiber fabric is impregnated with resin, and wf (fiber content by weight) is 40~40.
The one adjusted to 75% (prepreg) is suitable. When wf < 40%, only the resin flows during molding, resulting in poor appearance; when wf > 75%, parts are not impregnated with resin, resulting in poor appearance and reduced impact resistance. It was seen. Also,
It is also possible to form various patterns by changing the fiber fabric. To form the core 1, for example, an SMC is shaped to match the cavity shape formed by the upper and lower molds 3 and 2 (excluding the recess 21 into which the prepreg that becomes the striking part 11 is inserted), and this is shaped into the upper and lower molds. 3.2, and can be heated and press-molded, preferably containing carbon fibers adjusted to wf 25 to 60%. The fiber length and number of fiber bundles of the carbon fibers can be arbitrarily selected. These prepregs and SMC can be used in any position, and by selecting these positions, the appearance (pattern) of the head body can be freely designed. The mold temperature of the first upper and lower molds 3, 2 is 120 to 160°C, preferably 130 to 140°C, and the curing time (keep time) is about 2 to 5 minutes. After the core 1 shown in FIGS. 1 and 4 is formed in this way and taken out from the mold, it is set in a foaming mold (not shown) and a lightweight resin material is placed inside the hollow part 16. to form the foam 4 into the hollow part 16.
(See Figure 5). At this time, a shaft (not shown) is provided in the foam mold so that pin insertion holes 5, which will be described later, are formed in the foam 4.
The materials for the foam 4 include, for example, a so-called master batch consisting of 100 parts by weight of polyol, 1 part by weight of foam stabilizer, and 0.5 parts by weight of water, mixed with a curing agent (112 parts by weight) for about 15 seconds. Pour into a foaming mold that has been preheated to around 50°C and heat in a 50°C oven for 15 to 30 minutes.
Let it harden in about 20 minutes. The foam 4 formed in this way had a specific gravity of about 0.25 to 0.50. Next, as shown in FIG. 5, a pin insertion hole 5 is formed by removing a shaft (not shown) provided in the foam mold. Thereafter, as shown in FIG. 6, a synthetic resin material 10 (for example, SMC) that forms the head body 6 is wrapped around the foam 4 of the core 1, and the core 1 is molded into a second lower mold 20.
Set to 0. Similar to the first lower mold 2, this second lower mold 200 has a cavity formed from the placement piece 201A, and has a recess 1 for attaching the sole plate of the core 1.
A convex portion 220 corresponding to No. 7 is formed on the placement piece 220A. Further, a recess or protrusion 230 similar to the shaft insertion recess or protrusion 23 of the first lower mold 2 is provided in the second
It is formed at the bottom of the cavity of the lower mold 200.
A second upper mold 7 that is paired with the second lower mold 200 to form the head body 6 covering the core 1 is provided with a shaft pin 71 that is inserted into the pin insertion hole 5 . The second upper mold 7 and the second lower mold 200 are closed and heated and pressurized to form the head body 6 that covers the core 1 (see FIG. 7). At this time, core 1
recess 17 for attaching the sole plate (see Figure 3)
is positioned by fitting into the convex portion 220 of the second lower mold 200, and the shaft pin 71 also fits into the pin insertion hole 5.
By penetrating through the plate, the inclination of the head relative to the shaft can be maintained with high accuracy, and the entire front, back, left, and right directions are uniquely defined, and the 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 manner, the shaft pin 71 is vertically aligned and aligned with the operating direction of the second upper mold 7, so that the lie angle of the product is maintained constant. According to the above-mentioned example, the following No. 1 wood (driver) head was obtained. Volume...197cm Weight of ³ molded parts...160g Weight after attaching the sole plate...175g Maximum head width...77.8mm Depth of center of gravity (Z _G )...29.3mm Thickness of striking part...8mm Minimum thickness forming the outer periphery Thickness...3.5mm Lateral moment of inertia (Iχ)...1.9g・
mm·sec ² Note that the joint between the second upper and lower molds 7,200, 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 pin insertion hole 5 or the shaft insertion portion is not provided in the core 1, but is provided in the head body 6. . In addition, the core 1 in any of the embodiments includes the inserted striking surface 11 (the cross-hatched portion in FIGS. 4 and 5), the sole plate mounting recess 17, and one surface on both sides of this recess (the cross-hatched portion in FIG. 3). The hatching portion) was configured so as to be exposed on the outer surface even after the head body 6 was molded. Furthermore, the second
The bottom surface of the lower die 200 is tilted and attached to the shaft pin 71.
Although the second lower mold 7 is configured to descend vertically from above, there may be a case where the operating direction of the second lower mold 7 is inclined and descended at a certain angle. In this case, the bottom surface of the second lower mold 200 may be horizontal. Further, golf club heads (woods) obtained by this manufacturing method were as shown in the following table. In the table, W#1 is the No. 1 wood with a club length of 43 inches, W#3 is the No. 3 wood with a club length of 42 inches, and W
#4 indicates No. 4 with a wood of 41.5 inches, and W#5 indicates No. 5 with a wood of 41 inches. moment of inertia Iχ
As mentioned earlier, is the moment of inertia in the horizontal direction, and Ig is the moment of inertia in the vertical direction,
The units are g・mm・sec ² .

〔effect〕

As explained above, according to the present invention, a hard core made of synthetic resin having protrusions and recesses for positioning is formed in advance, and the hollow part of this core is filled with foam. 2. Positioning is done using the convex parts and concave parts within the cavity of the lower mold, so
When the head body is molded around the core in the second upper and lower molds, the core does not shift in position due to the clamping force of the second upper and lower molds. Furthermore, there is no risk that at least the foam that contacts the inner surface of the hollow portion of the core will be crushed by the mold clamping force. Therefore, the plate thickness of the head body can be formed to the thickness as designed. Therefore, it is possible to form a light and large head by reducing the thickness of the core and the thickness of the head body after calculating the strength to withstand the impact at the time of impact. The larger head expands the sweet area, and the lighter weight allows for better swings and faster head speed. Furthermore, the presence of the shaft pin allows the manufactured head to have an accurate lie angle. In the head manufactured by this invention, there is no variation in the plate thickness of the head body, and since the head body, core, and foam are all made of synthetic resin, they are completely integrated, and the head has a good balance. It also disappears. Furthermore, the foam present inside improves the feel on impact, and at least the portion of the foam surrounded by the core is free from deformation such as crushing.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the state in which the core is molded and taken out by the first upper and lower molds, Fig. 2 is a bottom view of the first upper mold, Fig. 3 is a plan view of the sole portion of the core, and Fig. 4 is a A perspective view of the core, FIG. 5 is a perspective view of the core filled with foam, FIG. 6 is a perspective view showing the preparation process for molding the head body, and FIG. 7 is a perspective view of the core with the second upper and lower molds closed. Cross-sectional view, Figure 8 is a cross-sectional view of the head, Figure 9
This figure is a detailed plan view of the inner surface of the sole section, with the upper portion taken away from the line AA in FIG. 8. DESCRIPTION OF SYMBOLS 1... Core, 2... First lower mold, 3... First upper mold, 4... Foam, 5... Pin insertion hole, 6... Head main body, 7... Second upper mold, 11... ...Strike department, 1
6... Hollow part, 23... Shaft insertion depression or protrusion, 32... Convex part, 71... Shaft pin, 2
00...Second lower mold.

Claims (1)

[Claims] 1. A first upper mold 3 having at least a convex portion 32 for forming a hollow portion 16 inside the core 1; The shaft pin 71 is inserted into the shaft insertion recess 23 into which the protrusion formed on the protrusion 32 is inserted, or the shaft pin 71 is inserted into the core 1.
A synthetic resin material is put into the first lower mold 2 in which a protrusion 23 is formed to form a part of the pin insertion hole 5 serving as a passage, and the mold is clamped and heated and pressurized to apply pressure during molding of the head body 6. A step of forming a core 1 that does not deform under pressure; and a step of taking out the core 1 from the first upper and lower molds 3 and 2, foaming a lightweight resin material into the hollow part 16 of the core 1, and filling the foam 4 with the core 1. The head body 6 is wrapped around the core 1 and the foam 4.
A step of attaching a synthetic resin material 10 which is a molding material of a shaft pin 71 that is inserted into the assumed shaft attachment position formed in the molding material of the core 1, the foam 4, and the head body 6;
The second upper mold 7, which is provided along the operating direction of the mold, and the second lower mold 200 are clamped and heated and pressurized to mold the head body 6, and the head body 6, the foam 4, and the core 1 are molded together. 1. A method of manufacturing a golf club head, comprising: forming a pin insertion hole 5 for shaft insertion in the head. 2. A synthetic resin material is put into the first upper mold 3, which is equipped with a convex part 32 for forming at least the hollow part 16 inside the core 1, and the first lower mold 2, which is equipped with at least one of a concave part or a convex part. A process of clamping the mold and applying heat and pressure to form a core 1 that will not be deformed by the pressure applied during molding of the head body 6; and a process of taking out the core 1 from the first upper and lower molds 3 and 2 and forming the hollow part of the core 1. A step of foaming a lightweight resin material into the portion 16 and filling the foam body 4, and a step of filling the head body 6 so as to wrap the core 1 and the foam body 4.
A step of attaching a synthetic resin material 10 which is a molding material of A shaft pin 71 is provided at the planned position of the pin insertion hole 5 formed in the head body to be formed so as to cover the core 1, and this shaft pin 71 is provided along the operating direction of the mold. The second upper mold 7 and the second lower mold 200 are clamped and heated and pressurized to mold the head body 6, and at the same time, forming a pin insertion hole 5 for shaft insertion in the head body 6. A method for manufacturing a golf club head characterized by: