JP2018183333A - Manufacturing method of golf club head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a CFRP-made golf club head that is light-weight, has high flexibility of adjusting the gravity center, and is superior in mechanical characteristics.SOLUTION: A manufacturing method of a golf club head is provided in which CFRP comprising a carbon fiber and a thermosetting resin is used by 20-150 g. The manufacturing method of the golf club head comprises: a preform step of making a preform comprising an integral part where a cut prepreg having multiple cut are shaped into a shape integrating a sole part and a crown part and having substantially a golf club head shape; a molding step of setting the preform in a mold to perform heating and pressurization, and thereby making the CFRP; and a face installation step of installing a metallic face.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a method for manufacturing a golf club head that is lightened using CFRP (carbon fiber reinforced plastic).

  Since a golf club head has a different feel at impact depending on the position of the center of gravity, a high degree of freedom in controlling the position of the center of gravity with a weight or the like is required. For that purpose, it is important to make the body as light as possible. As a method for reducing the weight of a golf club head body, the use of fiber reinforced plastics with high specific rigidity, particularly CFRP using carbon fibers as reinforced fibers, is expanding.

  For example, Patent Document 1 uses a BMC (Bulk Molding Compound) with good moldability to facilitate the manufacture of a golf club head including a fiber reinforced plastic. In patent document 2, the moment of inertia is improved by using a fiber reinforced plastic suitably and using a surplus weight for a peripheral part, reducing in weight. Patent Document 3 also manufactures a golf club head reduced in weight by using a fiber-reinforced plastic crown and sole. Patent Document 4 provides a golf club head that is lightweight by using a fiber-reinforced plastic crown and has high adhesion to a metal head.

JP 2013-255587 A JP 2014-8141 A JP-A-2005-296609 JP 2010-51825 A

  However, there is room for further weight reduction by increasing the amount of CFRP used in the golf club head. For this purpose, it is necessary to reduce the thickness by using an intermediate base material that can reduce the joint as much as possible and can produce CFRP having high mechanical properties.

  The subject of the present invention pays attention to such a point, in particular, it is possible to produce a CFRP part with a reduced joint as much as possible, further reducing the weight of the main body, and having a high degree of freedom in adjusting the center of gravity by surplus weight, Another object of the present invention is to provide a method for manufacturing a golf club head having high mechanical properties.

In order to solve the above-described problems, a golf club head manufacturing method according to the present invention is a golf club head manufacturing method using 20 to 150 g of CFRP made of carbon fiber and a thermosetting resin, and includes the following integrated part: A preform process for producing a preform having a substantially golf club head shape, a molding process in which the produced preform is set in a mold and heated and pressed to form CFRP, and a metal face is formed on the molded CFRP. And a face attaching step of attaching the method.
(Integral part)
Insert a plurality of cuts into a prepreg composed of carbon fibers and resin oriented in one direction, and cut a plurality of cut prepregs or cut prepregs obtained by dividing at least some of the carbon fibers so that the fiber length is 5 to 50 mm. Shaped body obtained by pressing the laminated prepreg laminated body into a shape that presses against the male mold and integrates the sole part and the crown part

  According to the present invention, a golf club head is manufactured using a CFRP having no joint portion between a sole portion and a crown portion, and having a light body, a high degree of freedom in adjusting a center of gravity by an excess weight, and high mechanical characteristics. A method can be provided.

It is a conceptual diagram which shows an example of the golf club head in this invention. It is a conceptual diagram which shows an example of the mode of the shaping of the integral part in this invention. It is a conceptual diagram which shows an example of the schematic cross section of the preform in this invention. It is a conceptual diagram which shows the example of the shaping | molding process in this invention. It is a general | schematic fragmentary sectional view of the golf club head manufactured in the Example.

  In order to provide a lightweight CFRP golf head without a joint between a sole and a crown, the present inventors have intensively studied and substantially include a golf club head including a prepreg made of carbon fiber and a thermosetting resin. A method of manufacturing a golf club head, comprising: a preform process for manufacturing a preform having a shape; a molding process for forming a CFRP by setting the preform in a mold and heating and pressing; and a face mounting process for attaching a metal face However, this problem is solved by including an integral part in the preform. The weight of CFRP is preferably 20 to 150 g, more preferably 30 to 80 g in order to adjust the balance of the center of gravity.

  FIG. 1 shows an example of the configuration of a golf club head according to the present invention. The golf club head 20 of the present invention includes a crown portion 1, a sole portion 2, a neck portion 3, a face portion 4, and a weight portion 5. In the present invention, the crown portion and the sole portion are regions where the surface can be seen from directly above when the golf club head is placed on a horizontal surface with the neck portion facing up, and the portions other than the face portion are the crown portion and the face portion. A region excluding the portion and the crown portion is defined as a sole portion. Thereafter, unless otherwise specified, when the golf club head is placed on a horizontal surface with the neck portion facing up, the area of the crown portion is the area of the region visible from directly above, and the area of the sole portion is the region of the region visible directly below. The area.

  The face portion may include an impact surface on which the ball hits and a region where the impact surface and the sole portion / crown portion are joined. The face portion is preferably made of metal from the viewpoint of durability, and particularly preferably made of titanium. The neck portion connecting the golf club head and the shaft is included in either or both of the sole portion and the crown portion according to the above definition. The weight portion is a component that adjusts the weight balance of the golf club head, and is joined to the crown portion and the sole portion as necessary, and may be made of CFRP or metal. The weight portion may be plate-shaped or screw-shaped, and may have a structure in which the user of the golf club head can finely adjust the weight balance by combining them. In order to pursue design properties, golf club heads may be added with painting or decoration, and in the present invention, these generic names are referred to as decoration portions. The sole portion, crown portion, weight portion, and face portion may include a painted portion, but unless otherwise specified, the golf club head of the present invention does not include a decorative portion.

  A substantially golf club head-shaped preform means that when the preform is solidified, a golf club head portion other than the face portion, the weight portion, and the decorative portion can be formed without any additional base material. This refers to a prepreg shaped into a shape (hereinafter, unless otherwise specified, simply “preform” refers to a preform having a substantially golf club head shape). However, if the preform is only solidified, there is a need for drilling to attach a weight when burr generated by the flow of the substrate during heating and pressurization, or when the preform is converted to CFRP In addition, such a cutting allowance may occur. In the present invention, unless otherwise specified, a prepreg is a base material in which a carbon fiber oriented in one direction is impregnated with a resin, including a cut prepreg described later, and a plurality of prepregs are laminated even in the case of a single layer. Also includes laminates.

  In the present invention, carbon fibers having excellent specific strength and specific rigidity are used as reinforcing fibers constituting the prepreg. There is no limitation in particular in the kind of carbon fiber, What is necessary is just to select PAN system and a pitch system arbitrarily according to a use. Although there is no particular limitation on the resin, since a thermosetting resin is preferable from the viewpoint of formability, the thermosetting resin is used in the present invention. From the viewpoint of adhesiveness.

  The volume content of carbon fiber in the prepreg is preferably 40% or more from the viewpoint of mechanical properties, but if the carbon fiber content is too high, sufficient fluidity cannot be obtained in the molding step, and the density is generally higher than that of the resin. And the weight increases greatly, so 65% or less is preferable.

  The integral part in the present invention refers to a cut obtained by inserting a plurality of cuts into a prepreg and laminating a plurality of cut prepregs or cut prepregs obtained by dividing at least some of the carbon fibers so that the fiber length is 5 to 50 mm. This is a shaped body obtained by pressing one embedded prepreg laminate into a shape in which a sole portion and a crown portion are integrated by pressing against a male mold. The term “integrated” means that 60% or more of the joint between the sole portion and the crown portion is continuous without having a discontinuous joint portion such as an adhesive portion or a welded portion. More preferably, 80% or more of the joint portion between the sole portion and the crown portion is continuous without having a joint portion.

  FIG. 2 is a conceptual diagram showing an example of a state in which the cut portion prepreg 6 having a plurality of cuts 6 a is pressed against the male mold 7 to shape the integrated portion 8. The integral part may be a trimmed portion of the cut prepreg pressed against the male mold. By using the cut prepreg, a shape in which the sole portion and the crown portion are integrated without a joint portion can be formed. Since there is no joining portion, the sole portion and the crown portion are not peeled off, and high rigidity can be maintained even if the weight is light.

  Further, it is preferable that the crown portion of the integral portion has 80% or more of the area of the crown portion in the golf club head, and the sole portion of the integral portion has 80% or more of the area of the sole portion of the golf club head. By increasing the volume of the integral part, the rigidity of the golf club head of the present invention is ensured. Since the integral part may be trimmed after the molding process, it may be 100% or more of the area of the crown part and the sole part, but 150% or less is preferable in consideration of improvement in yield and biting into the female mold. .

  The cut prepreg preferably has all the reinforcing fibers divided by the cut. If the length of the reinforcing fiber divided by the cutting is too long, the shapeability will deteriorate and it will be difficult to shape the integral part, and if it is too short, the cutting prepreg will break when shaping into the integral part. Therefore, the length of the divided reinforcing fiber is preferably 5 to 50 mm. More preferably, it is 10-30 mm.

  If the length of the cut to be inserted into the cutting prepreg is too short, it will be difficult to shape the integral part due to a decrease in shaping, and if it is too long, the cutting prepreg will break when shaping into the integral part. Therefore, 0.5 to 5 mm is preferable. More preferably, it is 1-3 mm.

  When the angle formed by the notch inserted into the notch prepreg and the orientation direction of the reinforcing fiber of the notch prepreg (hereinafter referred to as fiber direction) (hereinafter referred to as the notch angle) is large, when forming into an integral part However, if it is too small, it becomes difficult to insert the cut stably. Therefore, the cutting angle is preferably 6 to 30 °. When notches having different positive and negative cutting angles are mixed in the cutting prepreg, it is preferable because the opening of the cutting is further suppressed.

  FIG. 3 shows a cross section of the integral part 8 including the neck part 3. The integral part may or may not be included up to the neck part, but preferably has an integral part having a crown part including the neck part in order to improve the strength of the neck part. When a plurality of integrated portions 8 and 8 are included in the preform as in the illustrated example, an integrated portion that does not include the neck portion may be included.

  The male mold may be made of metal or resin, but is preferably made of metal so that it can withstand sufficient heating and pressurization. In order to efficiently take out the CFRP after curing, it may be a male type that can be divided.

  While the preform is set in the male mold, it is sandwiched between the female molds. FIG. 4 shows a conceptual diagram in which the preform 21 set on the male mold 7 is sandwiched between the female molds 11. The female mold 11 is preferably sandwiched between two or more female molds as shown in the drawing so that it can be easily removed according to the shape of the golf club head. Between the female molds, a biting prevention groove 15 may be provided for preventing the female mold from being pushed completely by the biting of the base material. The female mold is also preferably made of a metal that can give sufficient pressure and has heat resistance.

  In the molding process, the preform sandwiched between the male mold and the female mold is heated and pressurized. The preform may be set in a preheated female mold and pressurized as it is, or the preform may be set in a normal temperature female mold and gradually heated while being pressurized.

  In the molding step, ribs made of CFRP may be generated on the crown portion or the sole portion. As in Patent Document 1, when replacing the crown part or the sole part with CFRP, it is possible to obtain a CFRP part having a rib by using a cut prepreg. In the present invention, for example, FIG. As shown, by providing the rib forming groove 14, the reinforcing fiber flows and flows in the forming step, and a rib can be generated in the crown portion or the sole portion. By making the ribs made of CFRP, it is possible to improve the rigidity while maintaining the light weight even if it is a thin crown portion or sole portion. The number and shape of the ribs are not limited, and a plurality of ribs or cross-shaped ribs may be provided as necessary.

  In the face attaching process, the metal face part is attached to the CFRP obtained by the forming process. The attachment method may be an adhesive or screwing, but it is preferable to use an adhesive from the viewpoint of weight. The bonding portion between the face portion and the CFRP may have the CFRP on the surface or the face portion on the surface.

  In the golf club head manufacturing method of the present invention, other steps may be included as long as the preforming step, the forming step, and the face attaching step are included. A painting process and a process of attaching weights may be added as necessary.

  In the present invention, the shaping method for the integral part may be performed manually or by using a press machine, but in order to form the integral part having a complicated shape with higher accuracy, it is performed manually. It is preferable that the cut prepreg or the cut prepreg laminate is manually pressed against the male mold to form a single part. When the cut prepreg laminate is manually pressed against the male mold, the cut prepreg laminate is easily stretched by appropriately heating the substrate using a dryer or the like. The cut prepreg that has been stretched and no longer fits in the mold may be appropriately cut to fit in the mold. As long as it fits in the mold, even if wrinkles remain in the preform, the cut prepreg flows in the molding process, and the wrinkles can be eliminated.

  When shaping the integral part, the cut prepreg may be a single layer or a laminate, but a cross-ply laminate in which the cut prepregs are laminated so that the fiber directions intersect at right angles is particularly formable. Is preferable. By using a cross-ply laminate, the cut prepreg is easily stretched in the direction of ± 45 ° with respect to the fiber direction, which is particularly preferable when forming into a male mold by hand. The cross-ply laminate may be constituted by three or more cut prepregs as long as the cross-ply laminate is constituted by cut prepregs whose fiber directions intersect at right angles.

  In a more preferred aspect of the present invention, the preform includes two or more integral parts, at least one of which has a substantially surface shape of the golf club head, and at least one of which has a substantially inner surface shape of the golf club head. An embodiment is mentioned. As shown in FIG. 4, the integral part having the substantially surface shape of the golf club head refers to the integral part 9 along the female die 11, and the integral part having the substantially inner surface shape of the golf club head is the male part 7. The integrated part 10 along is shown. Since the neck portion has a thick structure because it can withstand an impact at the time of impact, an integrated portion that sandwiches the thick portion of a part 12 having a neck shape (hereinafter referred to as neck part) as shown in FIG. By doing, a neck part can be made into a strong thick part. Neck parts may be precured or semi-cured parts may be cured at the same time as the integral part and adhesive, or at the same time as the integral part during the molding process. For example, as shown in FIG. The prepreg may be formed by flowing. In the former case, it is preferable that the neck part is made of CFRP from the viewpoint of weight reduction, and the manufacturing method may be selected from injection molding, SMC, BMC, press molding by cutting prepreg, or casting. By increasing the contact area between the neck portion and the prepreg, the neck part is firmly bonded to the golf club head.

  In the present invention, the preform may include a prepreg 13 in which the sole portion and the crown portion are not integrated. Hereinafter, a prepreg that is not integrated is referred to as an additional laminated prepreg. For example, as shown in FIG. 4, by including the additional laminated prepreg 13, it is possible to provide an uneven design on the crown portion or the sole portion at the time of molding, or to increase the rigidity of the golf club head. For the purpose of simply increasing the rigidity, the additional laminated prepreg may be a prepreg without a cut, but for the purpose of providing an uneven shape, the additional laminated prepreg is preferably a cut prepreg. From the viewpoint of fluidity, the additional laminated cut prepreg preferably has a fiber length of 15 mm or less.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to the invention as described in an Example. In this example, a golf club head was manufactured using “Torayca” (registered trademark) prepreg sheet P3252S-15 (hereinafter, simply referred to as prepreg).

Example 1
<Preparation of cross-ply laminate of cut prepreg>
A cut was inserted into the prepreg to produce a cut prepreg. The length of the cut was 1 mm, and the cut angle was a cut pattern in which cuts of + 14 ° and −14 ° were alternately present and all the carbon fibers were cut by the cut. Two types of cut prepregs with different lengths of carbon fiber divided by the cut are prepared, and the cut prepreg with the carbon fiber divided into 25 mm is cut into the cut prepreg A and 12.5 mm. The cut prepreg was designated as cut prepreg B.

  Two pieces of the cut prepreg A were laminated so that the fiber directions intersected at right angles to produce a 350 mm × 350 mm cross-ply laminate A. Two cut prepregs B are laminated so that the fiber directions intersect at right angles, and a cross-ply laminate B having 60% of the area of the sole part and a cross-ply laminate C having 60% of the area of the crown part. Was made.

<Preform process>
The cross-ply laminate was pressed against the male mold to shape the integral part of the substantially inner shape of the golf club head. At the time of forming the integral part, the cross-ply laminate was appropriately heated with a drier and was allowed to follow the male shape while extending in the ± 45 ° direction.

  Subsequently, a cross-ply laminate of one cut prepreg B was additionally laminated from above the integral part having a substantially inner surface shape. The additional laminated prepregs were laminated on the sole part and the crown part to make 80% of the area of the sole part and the crown part, respectively.

  Next, the neck part was fitted on the integral part of the substantially inner surface shape. The neck part was made of a carbon fiber having a fiber length of 20 mm and an epoxy resin in a special mold in advance, and poured BMC with a fiber volume content of 40%, and the mold was closed and cured.

  Again, a 350 mm × 350 mm cross-ply laminate was prepared, and an integrated part having a substantially surface shape of the golf club head was formed from the integrated part of the substantially inner surface and the neck part.

<Molding process>
With the preform set in the male mold, it was set in a female mold at room temperature. As shown in FIG. 5A, the female mold was a female mold that can be shaped into a surface shape having no irregularities in both the crown portion and the sole portion, as shown in the schematic cross-sectional structure of the preform 22 after shaping. Using a press machine, the crown part and the sole part were heated while being pressurized so that a pressure of 1 MPa was applied. The surface of the press machine was set at 150 ° C., and the preform that became CFRP was taken out 1 hour after the start of pressurization. The female mold was a split mold, and the CFRP was removed from the male mold while the female mold was split.

<Weight measurement>
Unnecessary portions such as burrs were trimmed to obtain a CFRP having a predetermined shape from the CFRP that had undergone the molding process. When the weight of the obtained CFRP was measured with an electronic balance, it was 35 g.

<Completion of golf driver>
A titanium face and sole were attached to the CFRP removed from the mold using an adhesive. The adhesive was 3M DP420 and cured at 80 ° C. for 20 minutes. Then, 20 g of parts were attached as weights, and CFRP was used as a golf club head. Subsequently, a CFRP shaft (product number: HONMA VIZARD EX-Z65) was fixed to the neck portion with an adhesive (product number: hard rock).

<Blow sound>
Five test hitters with an average score of 80 to 90 made a test hit and evaluated the hitting sound. As a result, it was confirmed that the hitting sound was close to a metal sound.

<Durability>
No abnormalities were found when the total number of trials was 3000.

(Example 2)
As shown in FIG. 5 (b), the female mold is a female mold that can be shaped into a surface shape with irregularities on the sole portion as shown in the schematic cross-sectional structure of the preform 23 after shaping, and the amount of additional laminated prepreg of the preform A golf club head was manufactured in the same manner as in Example 1 except that the ratio was increased by a factor of 3, and a golf driver was completed. CFRP was also filled in the unevenness of the sole portion, so that a golf club head having a good design was obtained. The weight of CFRP was 43 g. The striking sound was similar to that of Example 1 in the same manner as in Example 1, and no abnormalities were observed in the durability at 3000 points.

(Comparative Example 1)
Shape shaping was attempted in the same manner as in Example 1 except that a prepreg without a cut was used instead of the cut prepreg A. However, when shaping the integral part, the cross-ply laminate A could not be extended, wrinkles were generated, and the integral part could not be shaped.

(Comparative Example 2)
Instead of shaping the integral part, instead, the laminate having the shape of the sole part and the crown part is cut out from the cross-ply laminate A and pasted to the locations corresponding to the male sole part and the crown part, respectively. A golf club head was manufactured under the same conditions as in Example 1 except that the golf driver was completed. The weight of CFRP was 35 g.

  When the impact sound was evaluated, the sound was slightly dry compared to Examples 1 and 2. When the durability was confirmed, cracks entered between the sole portion and the crown portion after 50 shots, and they were cracked.

1: Crown portion 2: Sole portion 3: Neck portion 4: Face portion 5: Weight portion 6: Cut prepreg 6a: Cut 7: Male die 8: Integral portion 9: Integral portion 10 having a substantially surface shape: Approximate inner surface shape Integral part 11: Female mold 12: Neck part 13: Additional laminated prepreg 14: Groove for rib forming 15: Groove for preventing biting 20: Golf club head 21: Preform 22, 23: Preformed preform

Claims (5)

A golf club head manufacturing method using 20 to 150 g of CFRP made of carbon fiber and thermosetting resin,
A preform process including a preform including the following integrated part and having a substantially golf club head shape;
A molding step of setting the produced preform to a mold and heating and pressurizing it into CFRP;
A face attaching step of attaching a metal face to the molded CFRP;
A method for manufacturing a golf club head, comprising:
(Integral part)
Insert a plurality of cuts into a prepreg composed of carbon fibers and resin oriented in one direction, and cut a plurality of cut prepregs or cut prepregs obtained by dividing at least some of the carbon fibers so that the fiber length is 5 to 50 mm. Shaped body obtained by pressing the laminated prepreg laminated body into a shape that presses against the male mold and integrates the sole part and the crown part   The golf club head manufacturing method according to claim 1, wherein the cut prepreg or the cut prepreg laminate is pressed against a male mold to form an integrated part.   The golf head manufacturing method according to claim 2, wherein a cut prepreg laminate in which a plurality of cut prepregs are laminated so that the fiber directions intersect is pressed against a male mold to form an integrated part.   The preform includes two or more integral parts, at least one has a substantially surface shape of the golf club head, and at least one has a substantially inner surface shape of the golf club head. A method for producing a golf club head according to claim 1.   The golf club head manufacturing method according to claim 1, wherein the preform further includes a prepreg in which a sole portion and a crown portion are not integrated.

Images