JP5244068B2 - Golf club head and manufacturing method thereof - Google Patents

Description

  The present invention relates to a golf club head and a manufacturing method thereof.

  In golf play, many golfers want to fly a golf ball farther and more reliably. The flying distance is mainly required for wood type clubs. Wood, stainless steel, aluminum alloy, titanium alloy, fiber reinforced plastic, etc. are used for the club head of the wood type club.

  Aside from advanced players such as professional golfers and top amateurs, it is almost impossible for most general golfers to hit the center of the face (hereinafter referred to as “sweet spot”) where the distance travels most. Thus, in recent golf club development, the main focus is on how to expand the appropriate hitting ball portion (hereinafter referred to as “sweet area”) where the hit distance of the hit ball does not drop.

  In the patent document 1, the present applicant has proposed a golf club head with an expanded sweet area. The golf club head of Patent Document 1 reduces the rigidity of the body portion by making the plate thickness of the body portion thinner than before. Thereby, the bending in a body part is increased and the repulsive force of a ball is improved. Further, since the rigidity of the face portion is larger than that of the body portion, even when hitting with a spot other than the sweet spot, non-uniform deformation of the face portion is suppressed, and there is an effect that the flight distance is less reduced.

WO2008 / 102501

  The golf club head described in Patent Document 1 has an effect of expanding the sweet area, but there is room for further improvement in order to industrially produce the golf club head described above.

  The crown and the sole constituting the body part or the joint part such as the body part and the face part needs to have a certain thickness. For example, when joining by welding (including crimp welding, pressure welding, friction stir welding), the joining portion needs to have a thickness that does not cause deformation due to high-temperature heat during welding. Even when joining with an adhesive, it cannot be stably fixed if the joining portion is thin.

  As described in Patent Literature 1, the body portion thickness reduction treatment can be performed by chemical milling (pickling). In this case, masking is performed on the portion where the thickness is not desired to be pickled. By this processing, a step is generated between the masked portion and the thickness-reduced portion. Since stress concentrates on the step portion, the golf club head may be damaged by repeated shots.

  Such a problem does not occur if the thickness of the portion that is not the thickness-reduced portion is changed to a tapered shape to eliminate the step. However, in order to realize a tapered plate thickness, it is necessary to perform a polishing process. Therefore, this method is not suitable for industrial production.

  SUMMARY OF THE INVENTION In view of the above background, an object of the present invention is to provide a golf club head that is easily industrially manufactured and has an expanded sweet area.

  The golf club head of the present invention is a golf club head having a main part having a hollow structure and a face part joined to the main part so as to close an opening of the main part, the main part comprising: A first portion including a joint portion with the face portion and a second portion having a thickness smaller than that of the first portion, and a boundary between the first portion and the second portion is wavy.

  Thus, by making the boundary (step) between the first portion and the second portion having different plate thicknesses wavy lines, the stress when the ball is hit is dispersed in multiple directions at the step. Thereby, durability of a golf club head can be improved. In addition, by adopting a configuration in which a step may be left in the body portion, it is possible to easily produce industrially, for example, a thickness reduction process can be performed by pickling. The “first portion” includes a portion having a certain thickness such as a crown and a sole constituting the body portion or a joint portion such as the body portion and the face portion.

  In the golf club head of the present invention, the main part has a crown constituting the upper surface and a sole constituting the lower surface, and the first portion includes a portion for joining the crown and the sole. Good.

  With this configuration, it is possible to avoid stress concentration at the step between the first portion for joining the crown and the sole and the second portion having a small plate thickness.

  In the golf club head of the present invention, the first portion may include a rib formed on the main part.

  With this configuration, the rigidity of the golf club head is increased without significantly increasing the weight due to the rib, and stress concentration at the step can be avoided by making the step wavy.

  In the golf club head of the present invention, the average thickness of the second portion may be 0.1 to 0.6 mm. Further, the height of each wave constituting the wavy line boundary may be preferably 1 to 15 mm, and more preferably 2 to 8 mm. The first portion may have a distance from a joining line to the wavy border of 4 to 15 mm.

  By setting the second portion of the body portion to be 0.1 to 0.6 mm, it is possible to increase the deflection of the body portion when the ball is hit and to increase the repulsive force of the ball. Further, when the height of each wave constituting the wavy line boundary is less than 1 mm, the effect of stress distribution at the wavy line boundary cannot be sufficiently obtained. On the other hand, when the height of each wave exceeds 15 mm, the rigidity of the body portion increases due to the increase in the area of the first portion, and thus it is difficult to obtain the effect of improving the flight distance due to the repulsive force of the body portion. By setting the height of each wave to 1 to 15 mm, it is possible to improve the durability of the golf club head and improve the flight distance. If the distance from the joining line to the wavy border constituting the wavy border is less than 4 mm, the effect of the load applied at the time of joining to the stepped part will be weakened, so the appearance will deteriorate due to thermal shrinkage during welding Is likely to occur, and further, it is damaged from the stepped portion during a shot. On the other hand, when the distance from the joining line to the wavy line boundary exceeds 15 mm, the rigidity of the body part increases due to the increase in the area of the first part, and thus the effect of improving the flight distance due to the repulsive force of the body part is obtained. It becomes difficult. By setting the distance from the joining line to the wavy line boundary to 4 to 15 mm, it is possible to improve the durability of the golf club head and improve the flight distance. The “joining line” is a line corresponding to the side to which the members to be joined are joined, and the distance to the wavy border is the shortest distance from the joining line to the wavy border (that is, Distance to the apex of the wave closer to the joint line).

  A method for manufacturing a golf club head according to the present invention is a method for manufacturing a golf club head having a main part having a hollow structure and a face part joined to the main part so as to close an opening of the main part. Masking a first portion including a joint portion with the face portion of the main component, the masking step having a wavy shape at the boundary with the second portion not masked, and the main component Picking and thinning, removing the masking, and joining the main part and the face part.

  Thus, by making the boundary between the first portion and the second portion having different plate thicknesses wavy, the stress when hitting the ball is dispersed in multiple directions at the step. Thereby, durability of a golf club head can be improved.

  According to the present invention, by making the boundary between the first part and the second part having different plate thicknesses into wavy lines, the durability of the golf club head can be enhanced and industrially easily produced. Has an effect.

It is a figure which shows the external appearance of the golf club head of 1st Embodiment. 1 is a cross-sectional view of a golf club head according to a first embodiment. It is a figure which shows the crown of 1st Embodiment. It is a figure which shows the sole of 1st Embodiment. It is a figure explaining the wavy which comprises a boundary. It is a figure which shows the manufacturing method of the golf club head of 1st Embodiment. It is a figure which shows the crown of 2nd Embodiment. It is a figure which shows the sole of 2nd Embodiment. (A) It is a figure which shows the variation of a wavy border. (B) It is a figure which shows the variation of a wavy border. (C) It is a figure which shows the variation of a wavy border. (D) It is a figure which shows the variation of a wavy border.

Hereinafter, golf club heads according to embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a view showing the appearance of the golf club head according to the first embodiment. The golf club head 1 has a face portion 2, a body portion 5, and a tail portion 8. The face portion 2 is divided into a face plate 3 and a face body 4. The face body 4 is provided with a neck portion 9 to which a shaft (not shown) is connected. The body part 5 is divided into a crown 6 and a sole 7.

  The golf club head 1 has a volume of 400 to 468 cc and a mass of 185 to 208 g, preferably 193 to 203 g. If the range of the mass of the golf club head 1 is smaller than 185 g, the ball loses to the ball when hit, and it is impossible to provide a good repulsive force to the ball. It is specified from this.

  FIG. 2 is a cross-sectional view of the golf club head. The face portion 2 includes a plate-like face plate 3 having a thicker central portion than a peripheral portion, and a bowl-shaped face body 4 having a hole into which the face plate 3 is fitted.

  The face plate 3 is made of Ti-4.5Al-3V-2Mo-2Fe alloy which is one of (α-β) type Ti alloys, and the face body 4 and the neck portion 9 are made of (α-β) type Ti alloys. It consists of Ti-6Al-4V alloy which is one of these. The face plate 3 is fixed to the face body 4 by welding the periphery of the face plate 3 to the face body 4. The neck portion 9 may be cast integrally with the face body 4 or may be welded to the face body 4. The mass of the face part 2 including the neck part 9 is 85 to 130 g, preferably 90 to 110 g, and more preferably 95 to 105 g.

  In the present embodiment, the face portion 2 is composed of the face plate 3 and the face body 4 which are separate members, but the face plate 3 and the face body 4 are integrally formed by forging. May be. Further, the face plate 3 may have a cup shape in which the entire outer periphery or a part of the outer periphery wraps around to the face body 4 side.

  The body portion 5 is made of a Ti-6Al-4V alloy and has a hollow structure inside. The face part 2 is joined to the body part 5 by welding. The body portion 5 includes a crown 6 on the upper surface side and a sole 7 on the lower surface side. The crown 6 and the sole 7 are joined together by welding to constitute a hollow body portion 5. In the present specification, in the body part 5, the face part 2 side is defined as “front part” and the opposite side is defined as “rear part”. A tail portion 8 is attached to the rear portion of the sole 7.

  The tail portion 8 has a through hole 10 in which a female screw portion is formed, and a nut 12 and a washer 13 are connected to a bolt 11 screwed into the female screw portion. The bolt 11 and the nut 12 are preferably made of a high specific gravity material such as tungsten. The mass of the tail portion 8 including the bolt 11, the nut 12, and the washer 13 is 20 to 70 g, preferably 30 to 60 g. The tail portion 8 is preferably as heavy as possible, but the above range is defined as the mass of the tail portion 8 so as to satisfy the above-described mass range (185 to 208 g, preferably 193 to 203 g) for the entire golf club head 1. In the present embodiment, the tail part 8 and the sole 7 are configured by separate members and the tail part 8 and the sole 7 are welded. However, a part of the sole 7 is used as the tail part 8 and the bolt 11 and nut 12 or a similar weight body may be attached inside or outside the head.

  The plate thickness of the body portion 5 includes thick plate portions 6a and 7a for welding to the face portion 2, thick plate portions 6b and 7b for welding to the tail portion 8, and thicknesses for welding the crown 6 and the sole 7. In the plate portions 6c and 7c (see FIGS. 3 and 4), it is about 0.8 mm, and the other plate portions (referred to as “thin plate portions”) 6d and 7d have an average plate thickness of 0.1 to 0.6 mm. The thickness is preferably 0.2 to 0.45 mm. The thick plate portions 6a to 6c and 7a to 7c correspond to the “first portion” recited in the claims, and the thin plate portions 6d and 7d correspond to the “second portion” recited in the claims.

  FIG. 3 is a view showing a crown 6 constituting the body portion 5, and FIG. 4 is a view showing a sole 7. As can be seen in FIG. 3, a step having a wavy shape is formed at the boundary between the thick plate portions 6a to 6c and the thin plate portion 6d. As can be seen from FIG. 4, in the sole 7 as well, a step having a wavy shape is formed at the boundary between the thick plate portions 7a to 7c and the thin film portion 7d.

  FIG. 5 is a diagram for explaining a wavy boundary. In both the crown 6 and the sole 7, the height of the wavy line is 1 to 15 mm, preferably 2 to 8 mm. The pitch of the wavy line (distance between vertices) is determined by the height of the wavy line. When the pitch is too large with respect to the height, the shape of the wavy line approaches a straight line, and it is difficult to obtain the effect of stress dispersion. If the pitch is too small with respect to the height, masking performed during the thickness reduction process becomes difficult. The pitch is preferably about 0.3 to 1.5 times the height of the wavy line. In addition, the distance from the weld line to the wavy border constituting the wavy border is 4 to 15 mm.

  The reason why the average plate thickness of the thin plate portions 6d and 7d of the body portion 5 is defined in the range of 0.1 to 0.6 mm is that if the plate thickness is less than 0.1 mm, the rigidity of the body portion 5 becomes too small. This is because, in addition to the fact that the ball cannot be repelled when the ball is hit, for example, during transportation, the ball bumps into another club and dents. On the other hand, if the plate thickness exceeds 0.6 mm, the weight of the body portion 5 becomes too large, and not only the bolt 11, nut 12 or a corresponding weight body suitable for the tail portion 8 cannot be disposed, This is because the rigidity of the portion 5 becomes too large, and the repulsion of the ball at the body portion 5 cannot be expected.

  In addition, the measurement of the average plate | board thickness of the body part 5 is performed using the three-dimensional shape measuring apparatus (non-contact three-dimensional digitizer VIVID 9i, Konica Minolta Sensing Co., Ltd.), for example. However, the method for measuring the average plate thickness is not limited to this, and any method may be used as long as the average plate thickness can be measured with the same degree of accuracy.

  Some conventional golf club heads have a thickness of the crown 6 in the range of 0.4 to 0.8 mm. However, the body portion of the golf club head 1 according to this embodiment including the sole 7 is included. There was no material in which the average plate thickness of the portion corresponding to 5 was in the range of 0.1 to 0.6 mm. This is intended to increase the launch angle and reduce the backspin amount by reducing the rigidity of the crown 6 without reducing the rigidity of the sole 7 so that the face surface faces upward during a shot. This is because the surplus weight obtained by making 6 thinner is distributed to the sole 7 to lower the center of gravity and to make it easier to raise the ball.

  In these golf club heads, the thickness of the sole 7 increases and the rigidity thereof increases. That is, it is a technical idea that the rigidity of the body part 5 is increased and the repulsive force of the face part 2 is improved. If the sole 7 has the same thickness as that of the crown 6, the face will not face upward when the ball is hit, and the flying distance will be reduced or the center of gravity will not be lowered. The problem of becoming a club arises.

  On the other hand, in the golf club head 1 according to the present embodiment, the bolt 11 and the nut 12 are added to the tail portion 8 so that the mass of the tail portion 8 is in the range of 20 to 70 g, preferably 30 to 60 g. As a result, the moment of inertia of the rectilinear movement of the tail portion 8 pushes out the entire face portion 2 through the body portion 5, so that the above problem can be solved. Moreover, since the rigidity of the whole body part 5 falls by making the average board thickness of the thin board parts 6d and 7d of the body part 5 0.1-0.6mm, Preferably 0.2-0.45mm, When the ball is hit, the deflection of the body portion 5 increases and the repulsive force of the ball is improved.

  In other words, the golf club head according to the present embodiment is a technical idea in a direction in which the rigidity of the body portion 5 is reduced, which is completely opposite to the development direction of the conventional golf club head. Further, since the overall thickness of the body portion 5 is thin, the mass of the body portion 5 is lighter than that of a conventional golf club head. Accordingly, the mass of the tail portion 8 is heavier than the conventional golf club head, such as 20 to 70 g, while maintaining the total mass of the golf club head 1 in the range of 185 to 208 g. . When the mass of the tail part 8 is less than 20 g, the pushing effect of the body part 5 by the tail part 8 is drastically reduced. On the other hand, even if the mass of the tail portion 8 exceeds 70 g, the above effect is not reduced. However, considering that the mass range of the golf club head 1 for driving is 185 to 208 g, the tail is substantially reduced. The mass of the part 8 does not exceed 70 g. That is, the upper limit value of the mass of the tail portion 8 is not determined by the presence or absence of the above effect, but is a value determined from the feasibility.

[Production method]
FIG. 6 is a diagram showing a manufacturing process of the golf club head 1 according to the present embodiment. A method for manufacturing the golf club head 1 of the present embodiment will be described with reference to FIG.

  First, each member of the face body 4, the crown 6, the sole 7, and the tail portion 8 including the neck portion 9 is manufactured (S10). As a main method for manufacturing the face body 4 including the neck portion 9, there is a casting method using a Ti-6Al-4V alloy. As another method, after forging a round bar into a cup shape, a pipe-shaped neck portion is produced. There is also a method of manufacturing 9 by welding. The tail portion 8 is manufactured by casting or forging. The manufacturing method of the crown 6 and the sole 7 uses a plate material having high workability such as Ti-15V-3Cr-3Sn-3Al, and further a plate material having a thickness of 0.8 to 1.2 mm in order to ensure the thickness of the welded portion. And press working. In the present embodiment, the average thickness of the body portion 5 (crown 6, sole 7) is in the range of 0.1 to 0.6 mm, so that the thickness is reduced by pickling. Hereinafter, the thickness reduction process will be specifically described.

  Masking is performed on the thick plate portion to be welded among the crown 6 and the sole 7. As the thick plate portion, there are portions 6a and 7a including a welded portion of the face body 4, portions 6b and 7b including a welded portion of the tail portion 8, and portions 6c and 7c including a portion where the crown 6 and the sole 7 are welded to each other. . The reason for masking the thick plate portion is that when the plate thickness of the thick plate portions 6a to 6c and 7a to 7c is reduced, the crown 6 and the sole 7 are deformed by high heat during welding.

  A tape is affixed to a portion of the crown 6 or the sole 7 that is desired to be thinned (a portion that will become “thin plate portions 6d, 7d” in the future) (S12). As the tape, a wavy tape is used at the boundaries between the thick plate portions 6a to 6c and 7a to 7c. Next, with the tape applied, a maskant is applied to the crown 6 and the sole 7 (S14), and the tape is removed after the coating is completed (S16). As a result, the thick plate portions 6a to 6c and 7a to 7c are masked with wavy lines at the boundaries.

  After the masking is completed, the crown 6 and the sole 7 are pickled (S18), and the unmasked portion is reduced in thickness. As an etching solution for pickling, for example, hydrofluoric acid, nitric acid, chromic acid, a surfactant, or the like is used. The concentration of the etching solution and the etching time can be appropriately adjusted from the average plate thickness and the final average plate thickness of the crown 6 and the sole 7. In pickling, it is preferable to move the crown 6 and the sole 7 from time to time so as to be evenly exposed to the etching solution.

  After the thickness is reduced to a desired thickness by pickling, the maskant is removed from the crown 6 and the sole 7 (S20). Next, the nut 12 and the washer 13 are fixed to the tail portion 8 with the bolts 11 to increase the mass of the tail portion 8 within a range of 20 to 70 g (S22). Subsequently, the crown 6 and the sole 7 from which the maskant has been removed are welded to form the body portion 5 (S24). Next, the face body 4 and the tail portion 8 are welded to the body portion 5 (S24). By welding and joining the face plate 3 made of Ti-4.5Al-3V-2Mo-2Fe alloy to the face body 4 (S24), the golf club head 1 is obtained.

  In the golf club head 1 according to the present embodiment, the average plate thickness of the thin plate portions 6d and 7d of the body portion is 0.1 to 0.6 mm, and the mass of the tail portion 8 is 20 to 70 g. With such a configuration, the rigidity of the body portion 5 can be reduced as compared with the conventional golf club head, and the tail portion 8 including the bolt 11 and the nut 12 is reduced by the amount of the reduced mass of the body portion 5. The mass of can be increased. As a result, since the deflection of the body portion 5 increases when the ball is hit, the repulsive force of the ball increases.

  Further, since the rigidity of the face part 2 is large with respect to the body part 5, non-uniform deformation (twisting) of the face part 2 can be suppressed even during off-center shots, so that the flight distance is less reduced. Further, when the body part 5 bent when the ball is struck is repelled, the entire face part 2 is pushed out through the body part 5 by the moment of inertia of the linear movement of the tail part 8, but the mass of the tail part 8 is increased. The larger the is, the higher the repulsive force of the ball. Therefore, it is easy to hit without sacrificing the flight distance when hitting with a sweet spot, and the reduction of the flight distance during off-center shot can be minimized.

  Since the golf club head 1 of the present embodiment performs the thickness reduction process of the body portion 5 by pickling, the thickness can be reduced industrially. Moreover, although a level | step difference arises between thick plate part 6a-6c, 7a-7c and thin plate part 6d, 7d by pickling, the boundary of thick plate part 6a-6c, 7a-7c and thin plate part 6d, 7d Is a wavy line, so that the stress generated when the ball is hit is distributed in different directions, reducing the problem that the body portion 5 is easily damaged at the step between the thick plate portions 6a to 6c and 7a to 7c and the thin plate portions 6d and 7d. it can.

  In this embodiment, a Ti-4.5Al-3V-2Mo-2Fe alloy is used for the face plate 3 and a Ti-6Al-4V alloy is used for the face body 4 and the body part 5, but the material is limited to these materials. is not. Other (α-β) type Ti alloys and β type Ti alloys such as Ti-15V-3Cr-3Sn-3Al and Ti-15V-6Cr-4Al may be used. Pure Ti or a composite of Ti and other materials It may be a material or the like. The material is not limited to a material containing Ti alloy, and pure Al and Al alloy, pure Mg and Mg alloy, or composite material such as carbon fiber reinforced plastic (CFRP) and glass fiber reinforced plastic (GFRP). There may be. Note that the composite material includes Ti alloy, Al alloy, Mg alloy, CFRP, GFRP, and the like containing nanocarbon materials such as carbon nanotubes and fullerenes. Furthermore, at least two materials of Ti alloy, Al alloy, Mg alloy and composite material may be used. When carbon fiber reinforced plastic (CFRP) or glass fiber reinforced plastic (GFRP) is used, they are joined not by welding but by an adhesive. Further, in this case, pickling is not performed, but industrial production is easier with a configuration that allows a step.

  In the present embodiment, the tail portion 8 is composed of the through hole 10, the bolt 11, the nut 12, and the washer 13. However, the tail portion 8 is not limited to this configuration. Any configuration may be adopted as long as the mass of the tail portion 8 falls within a specified range, and the tail portion 8 may be integrally formed with the tail portion 8 or may be retrofitted to the tail portion 8. Good.

  Further, the mass range may be realized by manufacturing the tail portion 8 with a high specific gravity material such as tungsten so that the plate thickness is increased. That is, the above mass range may be realized only by the tail portion 8 without using the bolt 11 and the nut 12.

(Second Embodiment)
Next, a golf club head according to a second embodiment will be described. The basic configuration of the golf club head of the second embodiment is the same as that of the golf club head of the first embodiment, but the second golf club head is the golf club of the first embodiment. In addition to the structure of the head, the crown 6 and ribs for reinforcing the thin plate portions 6d and 7d of the sole 7 are provided.

  FIG. 7 is a view showing the crown 6 of the golf club head according to the second embodiment, and FIG. 8 is a view showing the sole 7. In the crown 6 of the golf club head according to the second embodiment, ribs 6e are formed on the thin plate portion 6d so as to connect the opposing thick plate portions 6a-6b and 6c-6c. The boundary between the thin plate portion 6d and the rib 6e is wavy. In addition, as shown in FIG. 8, the sole 7 has ribs 7e formed on the thin plate portion 7d so as to connect the opposing thick plate portions 7a-7b and 7c-7c. The boundary between the thin plate portion 7d and the rib 7e is wavy. By forming such ribs 6e, 7e, the strength of the body portion 5 (crown 6, sole 7) can be increased. The strength referred to here is not the strength against impact at the time of shot, but, for example, the strength against the depression of the body portion 5 due to the collision of another club head in the club back.

  In the present embodiment, the grid-like ribs 6e and 7e are taken as an example. However, the ribs are not necessarily grid-like and may be provided in various shapes including stripes. When the ribs 6e and 7e are provided on the body part 5, the mass of the body part 5 increases by the amount of the ribs 6e and 7e, so the mass of the tail part 8 must be reduced. When the ribs 6e and 7e are provided, it is preferable to provide as few ribs and sizes as possible.

  Next, a method for forming the ribs 6e and 7e will be described. When pickling the crown 6 and the sole 7, masking is applied to the area where the ribs 6e and 7e are formed, and the thickness is reduced to form the ribs. The masking and pickling processes are the same as in the first embodiment.

  When the ribs 6e and 7e are provided on at least one of the inner peripheral surface and the outer peripheral surface of the body portion 5, the average plate thickness of the body portion 5 means the entire plate thickness including the ribs 6e and 7e. By measuring the total thickness of the body portion 5 including the ribs 6e and 7e by performing a data process that equalizes the ribs 6e and 7e and uniforms the thickness of the entire body portion 5 with a three-dimensional shape measuring device. can do.

  Although the golf club head of the present invention has been described in detail with reference to the embodiment, the present invention is not limited to the above-described embodiment.

  In the above-described embodiment, the height of each wave constituting the wavy line boundary is substantially constant, but the height of the wavy line is not necessarily constant. For example, the wave height may be random as shown in FIG.

  In the above embodiment, the wave shape is a shape close to a sine curve. However, the wave shape is not limited to the above shape, and any wavy line shape that can disperse the stress applied to the step in multiple directions. Including. For example, the wavy line may be a zigzag as shown in FIG. 9B, a rectangular repetition as shown in FIG. 9C, or a sawtooth waveform repetition as shown in FIG. 9D. But you can.

  In the above embodiment, in the masking process, the tape is applied and the maskant is applied, and then the tape is peeled off. However, the masking may be performed by another method. For example, the maskant may be applied to the entire surface to be masked, and then the maskant of the portion not masked may be scribed and removed.

  In the above-described embodiment, a CFRP surface protection portion may be provided on part of the crown 6 and the sole 7 of the golf club head. Although the surface protection part is not limited to being made of CFRP, it is necessary to reduce the mass of the tail part 8 by the mass of the surface protection part. Therefore, a material that is as light as possible and has protective performance is preferable. In consideration, a composite material containing CFRP is preferable. The thickness of the CFRP surface protection portion is preferably 0.2 to 1.0 mm, more preferably 0.3 to 0.6 mm so as not to impair the original function of bending the entire body portion 5.

  In addition to surface protection, the surface protection unit can reduce sound during a shot. The sound may be excessive depending on the shape of the golf club head 1. In this case, the surface protection unit is expected to reduce sound. Sound vibrations are absorbed by the cover resin and the adhesive.

  Moreover, the surface protection part can reduce the nonuniformity of the thickness of the body part 5. In the present embodiment, the thickness of the body portion 5 is reduced by pickling. In the thickness reduction process, the plate thickness may be very small locally. In such a case, in the present invention, a cover is attached as the surface protection portion, and the cover thickness is added to the body plate thickness. The cover can reduce the ratio of the maximum thickness to the minimum thickness, and therefore can reduce the degree of uneven thickness. Further, in the thickness reduction process, there is a possibility that a through hole (pin hole) is partially generated in the body portion 5. In this case, the through hole is covered with the cover, and the appearance is improved.

  A golf club head is manufactured by changing the height of the wavy line of the wavy line-shaped step portion constituting the boundary between the thick plate portion and the thin plate portion and the distance from the weld line to the wavy line by the method of the first embodiment described above. The ball hitting test was conducted. Table 1 shows the experimental results.

  Example 1 is a golf club head in which the step portion is a straight line. When the step portion was a straight line, the golf club was damaged in one cool. One course is 1000 balls. From Example 2 and Example 3, when the height of each wave constituting the wavy line boundary is 0.8 mm, the effect of stress dispersion at the wavy line boundary cannot be sufficiently obtained, whereas 1.2 mm It turns out that durability will increase. Moreover, from Example 3 and Example 4, it turns out that durability can be improved further if the height of each wave is 2.1 mm.

  As can be seen from a comparison between Example 8 and Example 9, when the height of each wave exceeds 14 mm and becomes 20 mm, the average flight distance decreases. As can be seen from a comparison between Example 6 and Example 7, when the height of each wave is 9 mm, the average flight distance is slightly lower than that in the case of 8 mm.

  As can be seen from a comparison between Example 11 and Example 13, when the distance from the weld line to the boundary is less than 4 mm and becomes 2 mm, sufficient durability cannot be obtained, and an appearance defect occurs during molding. As can be seen from Example 14, even when the distance from the weld line to the boundary is 3 mm, an appearance defect occurs during molding. Further, as can be seen from a comparison between Example 8 and Example 12, it can be seen that when the distance from the weld line to the boundary exceeds 15 mm and reaches 40 mm, the average flight distance decreases.

  As described above, the present invention is useful as a golf club head that can be easily produced industrially. The present invention is applicable to any golf club head having a hollow structure. Specifically, it can be applied to a head for a driver, a head for a fairway wood, a head for a utility club (a utility club includes utility wood and utility iron), and the like.

DESCRIPTION OF SYMBOLS 1 Golf club head 2 Face part 3 Face board 4 Face body 5 Body part 6 Crown 6a-6c Thick board part 6d Thin board part 6e Rib 7 Sole 7a-7c Thick board part 7d Thin board part 7e Rib 8 Tail part 9 Neck part 10 Through Hole 11 Bolt 12 Nut 13 Washer

Claims (11)

A golf club head having a main part having a hollow structure and a face part joined to the main part so as to close an opening of the main part,
The main part includes a first portion including a joint portion with the face portion, and a second portion having a plate thickness thinner than the first portion,
A golf club head, wherein a boundary between the first portion and the second portion is wavy. The main part has a crown constituting the upper surface and a sole constituting the lower surface,
The golf club head according to claim 1, wherein the first portion includes a portion for joining the crown and the sole.   The golf club head according to claim 1, wherein the first portion includes a rib formed on the main part.   The golf club head according to claim 1, wherein an average plate thickness of the second portion is 0.1 to 0.6 mm.   The golf club head according to any one of claims 1 to 4, wherein a height of each wave constituting the wavy line boundary is 1 to 15 mm.   The golf club head according to any one of claims 1 to 5, wherein the first portion has a distance from a joining line to the wavy border of 4 to 15 mm. A method of manufacturing a golf club head comprising: a main part having a hollow structure; and a face part joined to the main part so as to close an opening of the main part,
Masking a first portion including a joint portion with the face portion of the main part, and performing a masking in which a boundary with a second portion not masked has a wavy shape;
Pickling and thinning the main parts;
Removing the masking;
Joining the main part and the face part;
A method of manufacturing a golf club head comprising:   The golf club head manufacturing method according to claim 7, wherein in the masking step, masking is also performed on a rib forming region.   9. The method of manufacturing a golf club head according to claim 7, wherein in the step of reducing the thickness, pickling is performed until the average thickness of the reduced portion becomes 0.1 to 0.6 mm.   The method of manufacturing a golf club head according to claim 7, wherein the height of each wave constituting the wavy line boundary is 1 to 15 mm.   The method of manufacturing a golf club head according to claim 7, wherein the first portion has a distance from a joining line to the wavy line boundary of 4 to 15 mm.