Golf club head manufacturing method

Abstract

This invention provides a manufacturing method that enables the production of golf club heads with concave grooves that achieve sharper groove shoulders and larger groove volume within the rules of golf. [Solution] A method for manufacturing a golf club head 1. The method includes the steps of: preparing a head body 2 equipped with a striking face 3; machining a first groove 11 in the striking face 4; and surface-processing the striking face 4 to obtain a second groove 12 while maintaining the shape of the groove bottom 30 of the first groove 11. The groove depth d1 of the first groove 11 is a groove depth exceeding the upper limit of the golf rules. The second groove 12 has a groove depth d2 that conforms to the golf rules. The surface processing is a blasting process in which an abrasive material 36 is impacted onto the striking face 4.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a golf club head.

Background Art

[0002] The following Patent Document 1 describes a method for manufacturing a golf club head in which a plurality of concave grooves are formed on a striking face.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] From the viewpoints of bite into the struck ball and cutting of turf intervening between the ball and the striking face, the concave grooves formed on the striking face desirably have a sharper groove shoulder portion and a larger groove volume within the range conforming to the golf rules.

[0005] Generally, in a method for forming concave grooves using a cutting tool or a mold, from the viewpoint of manufacturing, there is a trade-off relationship between a sharp groove shoulder and a groove volume. That is, when the groove depth deviates in the direction of becoming larger than the target during the processing of the concave groove, the groove volume becomes too large, and conversely, when it deviates in the direction shallower than the target, the groove shoulder becomes too sharp, and in either case, there is a problem of not conforming to the golf rules.

[0006] The present invention has been devised in view of the above actual situation, and the main object is to provide a method for manufacturing a golf club head capable of manufacturing a golf club head having concave grooves that realize a sharper groove shoulder and a larger groove volume within the golf rules.

Means for Solving the Problems

[0007] The present invention relates to a method for manufacturing a golf club head, comprising the steps of: preparing a head body having a striking face for striking a ball; machining at least one first groove extending in the toe-heel direction on the striking face; and surface-machining the striking face to obtain a second groove, such that the groove depth of the first groove is reduced while maintaining the shape of at least the groove bottom of the first groove, wherein the groove depth of the first groove exceeds the upper limit of the golf rules, the second groove has a groove depth that conforms to the golf rules, and the surface-machining is a blasting process in which an abrasive material is impacted onto the striking face. [Effects of the Invention]

[0008] By employing the steps described above, the present invention provides a method for manufacturing a golf club head that allows for the production of a golf club head with concave grooves that achieve sharper groove shoulders and a larger groove volume within the rules of golf. [Brief explanation of the drawing]

[0009] [Figure 1] This is a front view of a golf club head showing one embodiment of the present invention. [Figure 2] This is a cross-sectional view along line AA in Figure 1. [Figure 3] This is a flowchart showing the manufacturing procedure for head 1. [Figure 4] This is a schematic diagram illustrating the processing steps. [Figure 5] This is a magnified view of the tip of the blade. [Figure 6] This is a cross-sectional view of the tip of the blade. [Figure 7] This is a cross-sectional view of the first groove. [Figure 8] This is a cross-sectional view showing the state during the processing steps. [Figure 9] This is a schematic diagram illustrating the placement step S3 and the surface processing step S4. [Figure 10]This is a schematic diagram illustrating the processing steps of another embodiment. [Modes for carrying out the invention]

[0010] Hereinafter, one embodiment of the present invention will be described with reference to the drawings. The drawings contain exaggerations and representations that differ from the actual structural dimensional ratios in order to aid in understanding the present invention. Furthermore, where there are multiple embodiments, the same or common elements are denoted by the same reference numerals throughout the specification, and redundant descriptions are omitted.

[0011] Figure 1 is a front view of a standard state of a golf club head (hereinafter sometimes simply referred to as "head") manufactured by a manufacturing method of a golf club head (hereinafter sometimes simply referred to as "head") 1, which is one embodiment of the present invention. Figure 2 is a cross-sectional view taken along line AA of Figure 1. As shown in Figures 1 and 2, the head 1 includes a head body 2 and a hosel portion 3.

[0012] The head body 2 is equipped with a striking face 4 for striking the ball. The head body 2 further includes, for example, a top 5, a sole 6, and a toe 7.

[0013] The striking face 4 includes at least one, in this embodiment, a plurality of grooves 10 extending in the toe-heel direction. The striking face 4 includes, for example, a plurality of grooves 10 and a striking surface 8 for creating the grooves 10. The striking surface 8 is substantially flat, ignoring the irregularities caused by the blasting process described later.

[0014] The striking face 4 may also be provided with auxiliary grooves, which are not shown. These auxiliary grooves are formed with a smaller groove depth and width compared to the recessed groove 10. For example, the auxiliary grooves have a groove depth of 0.005 to 0.025 mm, a groove width of 0.10 to 0.50 mm, and a pair of groove wall surfaces that widen toward the opening at an inclination angle of 40 to 70 degrees. These auxiliary grooves are clearly distinguishable from the recessed groove 10.

[0015] The top 5 is the upper surface portion of the head 1 that extends from the upper edge of the hitting face 4 to the rear of the head. The sole 6 is the bottom surface portion of the head 1 that extends from the lower edge of the hitting face 4 to the rear of the head. The toe 7 is the portion farthest from the hosel portion 3 and is the portion that smoothly connects between the top 5 and the sole 6.

[0016] The hosel portion 3 has a shaft insertion hole 3a for holding a club shaft (not shown). The hosel portion 3 is, for example, formed in a cylindrical shape. Note that the shape of the head 1 is not limited to the one shown in the figure, and various shapes are adopted.

[0017] The head 1 of the present embodiment is configured as, for example, an iron type. The head 1 is, for example, entirely formed of a metal material. As the metal material, for example, carbon steel, stainless steel, titanium alloy, or maraging steel is desirable. Also, the head 1 may be formed of, for example, one type of metal material, or may be formed by combining two or more types of metal materials. Note that the head 1 may be configured as a wood type, utility type, or putter type in other embodiments.

[0018] The "reference state" of the head 1 is a state in which the head 1 is held at the lie angle α (shown in FIG. 2) and loft angle β (shown in FIG. 1) defined for the head 1 and placed on the horizontal plane HP. Also, in the reference state, the shaft axis center line CL of the head 1 is arranged within the vertical plane VP (shown in FIG. 2). The shaft axis center line CL is defined by the axis center line of the shaft insertion hole 3a formed in the hosel portion 3. The lie angle α is the angle formed by the shaft axis center line CL and the horizontal plane HP. The loft angle β is the angle of the hitting face 4 with respect to the vertical plane VP. In this specification, unless otherwise particularly mentioned, it is assumed that the head 1 is placed in this reference state. In the present embodiment, in the reference state, each concave groove 10 is formed parallel to the horizontal plane HP.

[0019] Furthermore, in this specification, the toe-heel direction is defined as the horizontal direction along the vertical plane VP. The direction perpendicular to the vertical plane VP is defined as the front-to-back direction of the head 1. In addition, the up-and-down direction along the vertical plane VP is defined as the up-and-down direction of the head 1.

[0020] Next, the manufacturing method of the head 1 will be described. Figure 3 is a flowchart of the manufacturing method of the head 1. As shown in Figure 3, the manufacturing method of the head 1 in this embodiment includes a step S1 of preparing the head body 2, a step S2 of processing the first groove 11 (shown in Figure 7), which will be described later, and a step S4 of obtaining the second groove 12 (shown in Figure 9), which will be described later. In addition, the manufacturing method of the head 1 in this embodiment includes a step S3 of placing a covering material (shown in Figure 9) 35 in the first groove 11, and a step S5 of removing the covering material 35. For convenience, step S1 is referred to as the preparation step S1, step S2 as the processing step S2, step S3 as the placement step S3, step S4 as the surface processing step S4, and step S5 as the removal step S5.

[0021] In the manufacturing method of the head 1 of this embodiment, first, a preparation step S1 is performed. In preparation step S1, for example, the head body 2 (head 1) is prepared. This head body 2 is equipped with a striking face 4 before the groove 10 is formed. The striking face 4 prepared in preparation step S1 may have markings for forming the groove 10.

[0022] Next, machining step S2 is performed. Figure 4 is a schematic diagram illustrating machining step S2. As shown in Figure 4, in machining step S2 of this embodiment, a first groove 11 (shown in Figure 7) is formed by cutting. The first groove 11 is formed by an NC machining machine F, such as a machining center or an NC milling machine.

[0023] The NC machining center F is equipped with a cutting tool 15 for carving the first groove 11, a support 16 for rotatably supporting the cutting tool 15, and a moving tool 17 for moving the support 16. The cutting tool 15 is preferably a cutting tool such as an end mill. The cutting tool 15 is rotated, for example, around a central axis c1. The moving tool 17 allows the cutting tool 15 to move in the toe-heel direction, the front-rear direction of the head 1, and the up-down direction of the head 1. In the machining step S2 of this embodiment, the head body 2 is held by a holder (not shown) inside the NC machining center F. The NC machining center F forms the first groove 11 by moving the cutting tool 15 in a predetermined direction, for example, by programming.

[0024] Figure 5 is an enlarged view of the tip of the cutting tool 15. As shown in Figure 5, the cutting tool 15 has, for example, a cutting surface 20 and a base 21. The base 21 is cylindrical. The base 21 is supported by a support 16. The striking face 4 (striking plane 8) is cut by at least a portion of the cutting surface 20 coming into contact with the striking face 4.

[0025] Unless otherwise specified, "cross-section of the cutting tool 15" in this specification means a cross-section that passes through and is parallel to the central axis c1. Also, "cross-section of the groove 10 (including the first groove 11 and the second groove 12)" in this specification means a cross-section that is perpendicular to the striking plane 8 and perpendicular to the longitudinal direction of the groove 10.

[0026] Figure 6 is a cross-sectional view of the tip of the cutting tool 15. The cross-section of the cutting tool 15 is symmetrical with respect to the central axis c1. Therefore, only the left side of the central axis c1 of the cutting tool 15 is shown in Figure 6. As shown in Figure 6, the cutting surface 20 has, for example, a top surface 23 and a side surface 24. The side surface 24 is located between the base body 21 and the top surface 23. The side surface 24 has a first arc portion 26 and a second arc portion 27.

[0027] In the cutting tool 15 of this embodiment, the top surface 23 is a plane, more specifically, a circular plane. The top surface 23 is, for example, perpendicular to the central axis c1. However, the top surface 23 is not limited to a plane; for example, it may be a curved surface or an uneven surface. Also, the top surface 23 does not have to be perpendicular to the central axis c1.

[0028] The first arc portion 26 has an arc-shaped cross-section. The first arc portion 26 is, for example, a concave arc in the direction centripetal to the central axis c1. The first arc portion 26 is connected to the base body 21. The first arc portion 26 is connected to the base body 21 in such a way that it forms a pointed, protruding corner portion 22. The second arc portion 27 has an arc-shaped cross-section. The second arc portion 27 is, for example, a convex arc in the direction centrifugal to the central axis c1. The first arc portion 26 and the second arc portion 27 are smoothly continuous. In the cross-section of the cutting tool 15, the radius of curvature r1 of the first arc portion 26 is formed to be larger than the radius of curvature r2 of the second arc portion 27.

[0029] Figure 7 is a cross-sectional view of the first groove 11 formed by the cutting tool 15 of this embodiment. As shown in Figure 7, the first groove 11 includes a groove bottom 30 formed by cutting the top surface 23 and a groove wall portion 31 formed by cutting the side surface 24. The groove wall portion 31 includes a groove shoulder portion 32 formed by a first arc portion 26, a rising portion 33 formed by a second arc portion 27, and a groove wall 34 connecting the rising portion 33 and the groove shoulder portion 32. In this embodiment, the rising portion 33 is smoothly connected to the groove bottom 30. The rising portion 33 is formed, for example, as a concave curved surface. The groove shoulder portion 32 connects, for example, the striking face 4 (striking plane 8) and the groove wall 34. In this embodiment, the groove shoulder portion 32 is smoothly connected to the striking plane 8. The groove shoulder portion 32 is smoothly connected to, for example, the groove wall 34. The groove shoulder portion 32 is formed, for example, as a convex curved surface. In this embodiment, the groove wall 34 extends in a straight line in cross-section.

[0030] Furthermore, in the cross-section of the first groove 11, the radius of curvature R of the groove shoulder portion 32 is set to a radius of curvature that conforms to the Rules of Golf. Also, the groove depth d1 of the first groove 11 formed in machining step S2 is set to a value exceeding the upper limit of the Rules of Golf. In this specification, the Rules of Golf refer to the "Rules of Golf" as defined by the USGA / R&A. Note that the first groove 11 is not limited to this configuration, and can take various shapes as long as it conforms to the Rules of Golf in all other respects except that the groove depth d1 exceeds the upper limit of the Rules of Golf.

[0031] Figure 8 is a cross-sectional view showing the state during machining step S2. As shown in Figure 8, during the machining of the first groove 11 (when the groove depth d1a of the first groove 11 conforms to the rules of golf), the radius of curvature R of the groove shoulder portion 32 does not conform to the rules of golf. Thus, in machining step S2 of this embodiment, as the groove depth d1a of the first groove 11 increases, the radius of curvature R of the groove shoulder portion 32 increases.

[0032] Next, the placement step S3 is performed. Figure 9 is a schematic diagram illustrating the placement step S3 and the surface processing step S4. In Figure 9, for convenience, the state after the surface processing step S4 is shown by a solid line, and the parts that change due to the surface processing step S4 are shown by a dashed line. Figure 9 shows a cross-section of the first groove 11. As shown in Figure 9, in this embodiment, the placement step S3 is performed by placing a covering material 35 in the first groove 11 to protect the groove bottom 30. The covering material 35 is preferably, for example, a resin or a cured paint. As the resin, for example, a synthetic resin made of a thermoplastic resin or a thermosetting resin is used. In particular, fluororesin is preferred as the resin. Also, a cured paint refers to a paint that has hardened over time. As the paint, a water-based paint, an oil-based paint, or a spray paint is used. In particular, urethane, rubber, etc. are preferred as the cured paint. Even when the next surface processing step S4 is performed, such a coating material 35 removes the impact surface 8 without removing the groove bottom 30, thus reducing the groove depth d1 of the first recessed groove 11.

[0033] From the viewpoint of maintaining the shape of the groove bottom 30 of the first groove 11 as described above, it is desirable that the thickness h of the covering material 35 in the groove depth direction be 10% or more of the groove depth d1 of the first groove 11. Furthermore, from the viewpoint of maintaining the radius of curvature R of the groove shoulder portion 32 after the surface processing step S4 within a range that conforms to the rules of golf, it is desirable that the covering material 35 be positioned at least on the groove bottom 30 side of the inner end 32i of the groove shoulder portion 32. The inner end 32i is the boundary between the groove shoulder portion 32 and the groove wall 34.

[0034] Next, the surface processing step S4 is performed. The surface processing step S4 is for surface processing the striking face 4 (striking surface 8). In this embodiment, the surface processing step S4 is a blast treatment in which an abrasive material 36 is impacted onto the striking face 4. The blast treatment can remove material from the striking surface 8. In Figure 9, the striking surface after the blast treatment is indicated by reference numeral 8a. Also, since the covering material 35 is placed on the groove bottom 30 in the placement step S3, the groove bottom 30 is not removed. As a result, in the surface processing step S4, the groove depth d1 of the first recessed groove 11 is reduced, and a second recessed groove 12 with a groove depth d2 that conforms to the rules of golf can be obtained. In addition, in the blast treatment, the abrasive material 36 is sprayed at an angle close to the normal direction of the striking surface 8. Such a blast treatment can, for example, treat the entire groove shoulder portion 32. Therefore, the blasting process effectively removes material from the groove shoulder portion 32 close to the striking plane 8, including the striking plane 8, as well as from the groove shoulder portion 32 close to the groove wall 34. Compared to milling, for example, such a blasting process can maintain the radius of curvature R of the groove shoulder portion 32 in accordance with the rules of golf. Thus, the manufacturing method of the head 1 in this embodiment makes it possible to manufacture a head 1 equipped with a groove 10 that achieves a sharper groove shoulder portion 32 and a larger groove volume within the rules of golf. In Figure 9, the surface 35k of the coating material 35 before the surface processing step S4 is shown by a dashed line, and the surface 35j of the coating material 35 after the surface processing step S4 is shown by a solid line.

[0035] The blasting process is not particularly limited, but well-known blasting methods such as sandblasting, shot peening, or grit blasting may be employed.

[0036] While not particularly limited, the difference (d1-d2) between the groove depth d1 of the first groove 11 and the groove depth d2 of the second groove 12 is preferably 0.01 mm or more, more preferably 0.02 mm or more, preferably 0.05 mm or less, and more preferably 0.04 mm or less. The difference (d1-d2) represents the thickness that is removed from the impact surface 8 in the surface processing step S4. The second groove 12 is the same as groove 10.

[0037] Next, removal step S5 is performed. In this embodiment, removal step S5 is performed by a well-known method suitable for removing the coating material 35. In removal step S5, for example, a solvent capable of dissolving the coating material 35 is used.

[0038] Figure 10 is a schematic diagram illustrating the processing step S2 of another embodiment. Figure 10 shows a cross-section of the first groove 11. As shown in Figure 10, in the processing step S2 of this embodiment, a press is performed on the striking face 4 by pressing a die 40 against it. The die 40 includes an upper die 40A and a lower die 40B that holds the head body 2. The upper die 40A has a forming surface 41 that includes, for example, a main surface 42 that forms a single plane and a plurality of small protrusions 43 that protrude from the main surface 42 and have an inverted shape of the first groove 11. The lower die 40B includes a mounting surface 44 that holds the back surface of the striking face 4. A plurality of first grooves 11 are formed by pressing the forming surface 41 of the upper die 40A against the striking face 4 (striking plane 8) of the head body 2 held by the lower die 40B.

[0039] Although particularly preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the illustrated embodiments and can be implemented in various modified forms.

[0040] [Note] The present invention includes the following embodiments.

[0041] [Invention 1] A method for manufacturing a golf club head, The steps include preparing the head body equipped with a striking face for hitting the ball, The step of machining at least one first groove extending in the toe-heel direction into the striking face, The process includes the step of surface-machining the striking face to obtain a second groove, such that the groove depth of the first groove is reduced while maintaining at least the shape of the groove bottom of the first groove, wherein the groove depth of the first groove is greater than the upper limit groove depth of the Rules of Golf. The second groove has a groove depth that conforms to the rules of golf. The aforementioned surface treatment is a blasting process in which an abrasive material is impacted onto the striking face. A method for manufacturing golf club heads. [Invention 2] The method for manufacturing a golf club head according to the present invention 1, wherein the step of machining the first groove is performed using a cutting tool or mold such that the radius of curvature of the groove shoulder portion between the groove wall and the striking face increases as the groove depth increases. [Invention 3] A method for manufacturing a golf club head according to the present invention 1 or 2, comprising the step of placing a covering material in the first groove to protect the bottom of the groove before the blasting process. [4th Invention] The method for manufacturing a golf club head according to the present invention, wherein the covering material is a resin. [5th ​​Invention] The method for manufacturing a golf club head according to the present invention, wherein the coating material is a cured paint product. [Invention 6] A method for manufacturing a golf club head according to any one of invention 1 to 5, wherein the thickness of the covering material in the groove depth direction is 10% or more of the groove depth of the first recessed groove. [7th Invention] A method for manufacturing a golf club head according to any one of claims 3 to 6 of the present invention, comprising the step of removing the coating material after the blasting process. [Explanation of Symbols]

[0042] 1 Golf club head 2 Head body 4. Hitting Face 11 First groove 12 Second groove 30 groove bottom 36 Abrasives d2 groove depth d1 groove depth

Claims

1. A method for manufacturing a golf club head, The steps include preparing the head body equipped with a striking face for hitting the ball, The step of machining at least one first groove extending in the toe-heel direction into the striking face, The process includes the step of surface-machining the striking face to obtain a second groove, such that the groove depth of the first groove is reduced while maintaining at least the shape of the groove bottom of the first groove, wherein the groove depth of the first groove is greater than the upper limit groove depth of the Rules of Golf. The second groove has a groove depth that conforms to the rules of golf. The aforementioned surface treatment is a blasting process in which an abrasive material is impacted onto the striking face. A method for manufacturing golf club heads.

2. The method for manufacturing a golf club head according to claim 1, wherein the step of machining the first groove is performed using a cutting tool or mold such that the radius of curvature of the groove shoulder portion between the groove wall and the striking face increases as the groove depth increases.

3. A method for manufacturing a golf club head according to claim 1, comprising the step of placing a covering material in the first groove to protect the bottom of the groove before the blasting process.

4. The method for manufacturing a golf club head according to claim 3, wherein the covering material is a resin.

5. The method for manufacturing a golf club head according to claim 3, wherein the coating material is a cured paint product.

6. The method for manufacturing a golf club head according to any one of claims 1 to 5, wherein the thickness of the covering material in the groove depth direction is 10% or more of the groove depth of the first recessed groove.

7. A method for manufacturing a golf club head according to any one of claims 3 to 5, comprising the step of removing the coating material after the blasting treatment.

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