Golf club head

Abstract

The ball initial speed, the high initial speed area, the take-off angle, the spinning, the hitting feeling and the durability are improved. When the tensile strength of a first layer (36), a second layer (38), and a third layer (40) constituting the face portion (14) is set as S1, S2, and S3, S3 > = S1 > S2. A first layer (36), a second layer (38), and a third layer (40) constituting a face portion (14) are deformed by hitting a ball with a face surface (1402), but at this time, the second layer (38), which has the lowest tensile strength and is soft, is sandwiched between the first layer (36) and the second layer (38), which have high tensile strength and are hard, so that the face portion (14) is deformed within an elastic deformation, and the ball is hit by the face portion (1402). Therefore, the first layer (36) is easily deformed as a surface having an expansion rather than as a point, thereby facilitating an increase in the contact area between the face surface (1402) and the ball and ensuring a long contact time between the face surface (1402) and the ball.

Description

Technical Field

[0001] This invention relates to golf club heads. Background Technology

[0002] A golf club head is proposed, which consists of a first metal plate and a second metal plate that supports the first metal plate via multiple ribs (see Patent Document 1).

[0003] In this golf clubhead, the spin of the ball is reduced by shifting the first metal plate in a direction along the clubface surface upon impact.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent No. 4340177 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] However, in the aforementioned prior art, multiple ribs may be over-deformed when the ball is struck, and the clubface will not return to its original shape even at the moment the ball leaves the clubface. In other words, the clubface may be over-deformed, leaving room for improvement in terms of ball initial velocity, high initial velocity region, launch angle, spin, impact feel, and durability.

[0009] The present invention was made in view of the above circumstances, and its object is to provide a golf club head that is conducive to improving ball initial velocity, high initial velocity region, launch angle, spin, hitting feel and durability.

[0010] Methods for solving problems

[0011] To achieve the above objectives, one embodiment of the present invention is a golf club head, wherein the golf club head is a hollow structure in which at least a portion of the clubface is composed of a first layer constituting the clubface surface, a second layer located on the side of the first layer opposite to the clubface surface, and a third layer located on the side of the second layer opposite to the first layer, characterized in that, when the tensile strengths of the first layer, the second layer, and the third layer are respectively set as S1, S2, and S3, S3≥S1>S2.

[0012] In addition, one embodiment of the present invention is characterized in that the hardness of the first layer is a durometer hardness D75 or higher and a Vickers hardness HV520 or lower, the hardness of the second layer is a durometer hardness A10 or higher and a durometer hardness D60 or lower, and the hardness of the third layer is a durometer hardness D85 or higher and a Vickers hardness HV520 or lower.

[0013] In addition, one embodiment of the present invention is characterized in that the tensile elastic modulus of the first layer is 8 GPa or more and 240 GPa or less, the tensile elastic modulus of the second layer is 0.5 MPa or more and 3000 MPa or less, and the tensile elastic modulus of the third layer is 10 GPa or more and 240 GPa or less.

[0014] In addition, one embodiment of the present invention is characterized in that the wall thickness of the first layer is 0.1 mm or more and 1.5 mm or less, the wall thickness of the second layer is 0.1 mm or more and 1.0 mm or less, and the wall thickness of the third layer is 2.0 mm or more and 5.0 mm or less.

[0015] In addition, one embodiment of the present invention is characterized in that the first layer is composed of any one of a metal material, a synthetic resin material, and a fiber-reinforced resin material; the second layer is composed of any one of a double-sided adhesive tape, a synthetic resin material, and an elastic material; and the third layer is composed of any one of a metal material, a synthetic resin material, and a fiber-reinforced resin material.

[0016] In addition, one embodiment of the present invention is characterized in that a thin-walled portion that is thinner than other portions is formed in the third layer, the thin-walled portion being formed by a recess that is open to the first layer on the front surface of the third layer opposite to the first layer, and the second layer is configured by filling the recess.

[0017] In addition, one embodiment of the present invention is characterized in that the front surface of the third layer, excluding the recess, overlaps with the first layer.

[0018] Furthermore, one embodiment of the present invention is characterized in that the golf club head has a hollow club head body, the club head body having an outer periphery portion of the clubface with an opening thereon, and a crown portion, a bottom portion, and a side portion connected to the outer periphery portion of the clubface; a plate-shaped third face member constituting the third layer is disposed on the inner side of the club head body on the inner side of the outer periphery portion of the clubface; and a plate-shaped second face member constituting the second layer is mounted overlapping the third face member on the inner side of the outer periphery portion of the clubface. The first plate-shaped first face member constituting the first layer is installed overlapping the second face member on the inner side of the outer periphery of the face member. The outer periphery of the third face member is in contact with the inner periphery of the frame-shaped inner periphery plate of the outer periphery of the face member and is installed by welding. The weld bead produced during the welding is contained in a weld bead containing space provided on one side away from the interior of the club head body, spanning the outer periphery of the third face member and the inner periphery of the mounting plate. The weld bead containing space is covered by the second face member and the first face member.

[0019] Furthermore, one embodiment of the present invention is characterized in that the golf club head has a hollow club head body, the club head body having an opening obtained by cutting off the portion of the face and crown near the face, the portion of the bottom near the face, and the portion of the side near the face; the third face member constituting the third layer has a third face body corresponding to the face and a third flange protruding from the outer periphery of the third face body toward the club head body; the second face member constituting the second layer has a second face body mounted overlapping the third face body, and a third flange protruding from the outer periphery of the second face body toward the club head body and overlapping the third flange, the portion of the crown near the opening, the portion of the bottom near the opening, and the portion of the side. The first face member constituting the first layer has a second flange that overlaps with the second face body and a first flange that protrudes from the outer periphery of the first face body toward the head body and overlaps with the second flange. The top end face of the third flange is abutted against the top end face of the crown portion forming the opening, the top end face of the bottom portion, and the top end face of the side portion and is installed by welding. The weld bead generated during welding is contained in a weld bead containing space provided on one side away from the interior of the head body, spanning the outer periphery of the third flange, the outer periphery of the crown portion, the outer periphery of the bottom portion, and the outer periphery of the side portion. The weld bead containing space is covered by the second face member and the first face member.

[0020] Invention Effects

[0021] According to one embodiment of the present invention, when the ball is struck by the clubface, the first, second, and third layers constituting the clubface deform. However, since the soft second layer is sandwiched between the hard first and second layers, the clubface deforms within an elastic deformation. Therefore, the first layer is more likely to deform as an extended surface rather than as a point, which can increase the contact area and contact time between the clubface and the ball.

[0022] Therefore, by ensuring a larger contact area and contact time, and utilizing the rebound effect, the backspin of the ball is reduced, resulting in a high takeoff angle and low spin, thus increasing the flight distance of the ball.

[0023] Furthermore, rebound refers to the elastic twisting and recovery phenomenon that occurs inside the ball due to contact with the clubface; in other words, it is the return of internal spin that is opposite to the backspin. Therefore, the greater the rebound, the less backspin the ball has.

[0024] In addition, because the clubface is flexed over a large area, the ball's initial velocity becomes high over a large area of ​​the clubface, which is beneficial for expanding the high initial velocity region.

[0025] In addition, because the soft second layer mitigates the stress during impact, it also mitigates the stress generated in the third layer, which helps ensure the durability of the clubface over a large area of ​​the clubface surface.

[0026] In addition, the soft second layer enhances the volume, height, and reverberation of the impact sound. This range becomes comfortable for golfers, resulting in a moderately softer feel that optimizes the feel over a wide area of ​​the clubface. Attached Figure Description

[0027] Figure 1 This is a front view of the golf club head of the first embodiment as viewed from the front of the clubface surface.

[0028] Figure 2 In the middle, (A) is Figure 1 (A) is a sectional view along line AA, and (B) is a partial sectional view showing a modified example.

[0029] Figure 3 In the diagram, (A)-(F) are schematic cross-sectional views showing the composition of the bar face.

[0030] Figure 4 In the diagram, (A) is a schematic cross-sectional view of the rod face of the second embodiment, and (B) is a schematic cross-sectional view of the rod face of the third embodiment.

[0031] Figure 5 In the diagram, (A) is a cross-sectional view of the golf club head according to the fourth embodiment, and (B) is a partial cross-sectional view showing a modified example.

[0032] Figure 6 This is a cross-sectional view of the golf club head according to the fifth embodiment.

[0033] Figure 7 In the diagram, (A)-(E) are cross-sectional views showing the manufacturing process of the golf club head according to the sixth embodiment.

[0034] Figure 8 This is a cross-sectional view showing a first modified example of the golf club head according to the first embodiment. (A) shows the state before assembly, and (B) shows the state after assembly.

[0035] Figure 9 This is a cross-sectional view showing a second variation of the golf club head according to the first embodiment. (A) shows the state before assembly, and (B) shows the state after assembly.

[0036] Figure 10 This is a cross-sectional view showing a first modified example of the golf club head according to the fourth embodiment. (A) shows the state before assembly, and (B) shows the state after assembly.

[0037] Figure 11 This is a cross-sectional view showing a second modified example of the golf club head according to the fourth embodiment. (A) shows the state before assembly, and (B) shows the state after assembly.

[0038] Figure 12 This is a graph showing the evaluation results of the experimental example under condition 1 in the implementation method.

[0039] Figure 13 This is a graph showing the evaluation results of the experimental example under condition 2 in the implementation method.

[0040] Figure 14 This is a graph showing the evaluation results of the experimental example under condition 3 in the implementation method.

[0041] Figure 15 This is a graph showing the evaluation results of the experimental example under condition 4 in the implementation method. Detailed Implementation

[0042] (First Embodiment)

[0043] First, the first embodiment will be described.

[0044] like Figure 1 , Figure 2 As shown in (A), in this embodiment, the golf club head 10A is a hollow wood-type golf club head (driver).

[0045] The clubhead body 12A of the golf clubhead 10A, excluding the clubface 14 described later, is made of metal or fiber-reinforced resin (FRP), or a combination of metal and fiber-reinforced resin.

[0046] As the metallic material, one or more of the following can be used: stainless steel, maraging steel, pure titanium, titanium alloy or aluminum alloy.

[0047] Examples of such titanium alloys include 6-4Ti and 8-1-1Ti.

[0048] As the fiber-reinforced resin material, carbon fiber reinforced resin (CFRP) and the like can be used.

[0049] The 10A golf clubhead has a face 14, a crown 16, a sole 18, and a side 20.

[0050] The golf club head 10A has an interior portion 22 surrounded by the face 14, crown 16, sole 18, and sides 20 (see reference). Figure 2 (A)) hollow structure.

[0051] The pole face 14 has a vertical height and extends to the left and right.

[0052] The crown 16 extends rearward from the upper part of the shaft face 14 with a wall thickness smaller than that of the shaft face 14.

[0053] The exposed surface on the outer side of the clubface 14 is the clubface surface 1402 that strikes the ball.

[0054] On the crown 16, on the side of the face surface 1402 and near the heel 24, there is a hosel 28 that is connected to the shaft S. By connecting the shaft S to the hosel 28, a golf club 100 is formed.

[0055] The bottom 18 extends rearward from the lower part of the face 14.

[0056] The side portion 20 extends along the back of the shaft face between the crown portion 16 and the bottom portion 18 and between the toe 24 and the heel 26 side edge of the shaft face 14.

[0057] like Figure 2 As shown in (A), the golf club head 10A is configured to include a hollow club head body 12A, a plate-shaped first face member 30, and a plate-shaped second face member 32. The club face 14 of the golf club head 10A is composed of the first and second face members 30 and 32 and the club face plate portion 34 of the club head body 12A.

[0058] In other words, the face 14 of the golf club head 10A is composed of a first layer 36 constituting the face surface 1402, a second layer 38 located on the side of the first layer 36 opposite to the face surface 1402, and a third layer 40 located on the side of the second layer 38 opposite to the first layer 36.

[0059] The first layer 36 is composed of the first bar surface member 30.

[0060] The second layer 38 is composed of the second bar face member 32 and is installed overlapping the side of the first bar face member 30 opposite to the bar face surface 1402.

[0061] The third layer 40 is composed of a face plate 34 of the clubhead body 12A, and a second face member 32 is mounted overlappingly on the outer surface of the face plate 34.

[0062] In this embodiment, the clubhead body 12A and the clubface plate 34 are made of the same material, such as 8-1-1Ti (casting material).

[0063] When the tensile strengths of the first layer 36, the second layer 38, and the third layer 40 are set as material strengths S1, S2, and S3 respectively, S3≥S1>S2.

[0064] (hardness)

[0065] The hardness of the first layer 36 is above D75 on a hardness tester and below HV520 on a Vickers hardness tester.

[0066] The hardness of the second layer 38 is above A10 and below D60 on a hardness tester.

[0067] The hardness of the third layer 40 is above D85 on a hardness tester and below HV520 on a Vickers hardness tester.

[0068] When the hardness of the first layer (36), the second layer (38), and the third layer (40) are within the ranges mentioned above, it is beneficial to achieve improvements in the ball's initial velocity, high initial velocity region, launch angle, spin, impact feel, and durability, as described later.

[0069] When the hardness of the first layer 36, the second layer 38, and the third layer 40 is less than the above range, the deformation of the clubface 14 during impact becomes too large (it becomes a deformation that is not within the elastic deformation described later). As a result, energy loss occurs during impact, and the effect of improving the ball's initial velocity, high initial velocity region, launch angle, spin, hitting feel, and durability is reduced.

[0070] When the hardness of the first layer 36, the second layer 38, and the third layer 40 exceeds the above range, the deformation (bending amount) of the clubface 14 at the time of impact is insufficient, thus reducing the effect of improving the ball's initial velocity, high initial velocity region, launch angle, spin, hitting feel, and durability.

[0071] (Tensive modulus of elasticity)

[0072] In addition, the tensile modulus of the first layer 36 is above 8 GPa and below 240 GPa.

[0073] The tensile modulus of the second layer 38 is above 0.5 MPa and below 3000 MPa.

[0074] The tensile modulus of the third layer 40 is above 10 GPa and below 240 GPa.

[0075] When the tensile modulus of elasticity of the first layer 36, the second layer 38, and the third layer 40 are within the above range, it is beneficial to achieve the improvement of ball initial velocity, high initial velocity region, takeoff angle, spin, hitting feel, and durability as described later.

[0076] When the tensile elastic modulus of the first layer 36, the second layer 38, and the third layer 40 are less than the above range, the deformation of the shaft face 14 at the time of impact becomes too large (it becomes a deformation that is not within the elastic deformation described later). As a result, energy loss occurs at the time of impact, and the effect of improving the ball's initial velocity, high initial velocity region, launch angle, spin, hitting feel, and durability is reduced.

[0077] When the tensile modulus of elasticity of the first layer 36, the second layer 38, and the third layer 40 exceed the above range, the deformation (bending amount) of the clubface 14 at the time of impact is insufficient, thus reducing the effect of improving the ball's initial velocity, high initial velocity region, launch angle, spin, hitting feel, and durability.

[0078] (Wall thickness)

[0079] In addition, the wall thickness of the first layer 36 is 0.1mm or more and 1.5mm or less.

[0080] The wall thickness of the second layer 38 is above 0.1mm and below 1.0mm.

[0081] The wall thickness of the third layer (40) is above 2.0 mm and below 5.0 mm.

[0082] When the wall thicknesses of the first layer (36), the second layer (38), and the third layer (40) are within the aforementioned ranges, it is beneficial to achieve improvements in the ball's initial velocity, high initial velocity region, launch angle, spin, impact feel, and durability, as described later.

[0083] When the wall thicknesses of the first layer 36, the second layer 38, and the third layer 40 are less than the ranges mentioned above, the deformation of the clubface 14 during impact becomes excessive (it becomes a deformation that is not within the elastic deformation range described later). As a result, energy loss occurs during impact, and the effect of improving the ball's initial velocity, high initial velocity region, launch angle, spin, hitting feel, and durability is reduced.

[0084] When the wall thickness of the first layer 36, the second layer 38, and the third layer 40 exceeds the above range, the deformation (bending amount) of the clubface 14 at the time of impact is insufficient, thus reducing the effect of improving the ball's initial velocity, high initial velocity region, launch angle, spin, hitting feel, and durability.

[0085] (Material)

[0086] The first layer 36 is composed of any one of the following: metal material, synthetic resin material, or fiber-reinforced resin material.

[0087] The second layer 38 is composed of any one of double-sided tape, synthetic resin material, or elastic material.

[0088] The third layer 40 is composed of any one of the following: metal material, synthetic resin material, or fiber-reinforced resin material.

[0089] As the elastic material used as the second layer 38, materials composed of rubber, resin, etc., can be listed. Examples of rubber include natural rubber, polybutadiene rubber, styrene-butadiene rubber, isoprene rubber, etc. Examples of resin include ionomer resin, urethane resin, polyester resin, polyamide resin, etc.

[0090] In addition, as an elastic material, the elastic adhesive 42 described later can be used. Figure 3 (A) Hot melt adhesives (sheet adhesives: thermoplastic sheet adhesives), etc. Hardness ranges from Shore A 40 to 90. Most examples are soft adhesives, etc.

[0091] As a metallic material used as the third layer 40, a rolled plate of 6-4Ti titanium alloy can be exemplified, for example.

[0092] In addition, the 10A golf club head, with a head volume of, for example, between 150cc and 460cc, can be used in golf club heads such as drivers, fairway woods, and utility clubs.

[0093] Next, refer to Figure 3 (A) to (F) describe specific configuration examples of the rod face 14. Furthermore, the dimensions, hardness, and material names in each of the following configuration examples are merely examples and do not limit the invention.

[0094] In addition, Figure 3 In the examples shown in (A) to (F), the structure of layer 3, 40, is common.

[0095] exist Figure 3 In the rod surface 14 shown in (A), the first layer 36 is composed of CFRP (carbon fiber reinforced resin) with a thickness of 0.75 mm.

[0096] The second layer 38 is composed of an elastic adhesive 42 with a thickness of 0.2±0.1mm (hardness A87 degrees on a hardness tester). The second layer 38 is bonded to the first layer 36 and the third layer 40 by the adhesive force of the elastic adhesive 42.

[0097] The third layer 40 is composed of titanium alloy with a thickness of more than 2.0 mm and less than 5.0 mm.

[0098] exist Figure 3 In the rod face 14 shown in (B), the first layer 36 is configured to contain CFRP with a thickness of 0.75 mm.

[0099] The second layer 38 consists of a urethane sheet with a thickness of 0.1 mm (hardness A90 on a hardness tester).

[0100] The third layer 40 is composed of titanium alloy with a thickness of more than 2.0 mm and less than 5.0 mm.

[0101] The second layer 38 is bonded to the CFRP of the first layer 36 by an epoxy adhesive 44A with a thickness of 0.25 mm, and is bonded to the titanium alloy of the third layer 40 by an epoxy adhesive 44B with a thickness of 0.25 mm.

[0102] Here, the hardness D of epoxy adhesives 44A and 44B is, for example, about 75 to 90 degrees.

[0103] Furthermore, the epoxy adhesives 44A and 44B used in the second embodiment and the third embodiment described below all meet the above-mentioned hardness requirements.

[0104] Therefore, the first layer 36 is configured to contain epoxy adhesive 44A, and the third layer 40 is configured to contain epoxy adhesive 44B.

[0105] exist Figure 3 In the rod face 14 shown in (C), the first layer 36 is configured to contain CFRP with a thickness of 0.75 mm.

[0106] The second layer 38 consists of a 0.25mm thick double-sided adhesive tape (foaming agent) 46. The double-sided adhesive tape 46 can be any of the conventionally known double-sided adhesive tapes, such as those using acrylic foam substrates, urethane foam substrates, polypropylene substrates, or polyester substrates.

[0107] The double-sided tape 46 of the second layer 38 is bonded to the first layer 36 by epoxy adhesive 44A with a thickness of 0.25 mm, and is bonded to the third layer 40 by epoxy adhesive 44B with a thickness of 0.25 mm.

[0108] The third layer 40 is composed of titanium alloy with a thickness of more than 2.0 mm and less than 5.0 mm.

[0109] Therefore, the first layer 36 is configured to contain epoxy adhesive 44A, and the third layer 40 is configured to contain epoxy adhesive 44B.

[0110] In this example, epoxy adhesives 44A and 44B are used to enhance the adhesive strength of the double-sided tape 46. If it is not necessary to enhance the adhesive strength of the double-sided tape 46, epoxy adhesives 44A and 44B can be omitted.

[0111] Alternatively, the second layer 38 may be composed solely of acrylic foam substrate, urethane foam substrate, polypropylene substrate, or polyester substrate after removing the adhesive components used in the double-sided tape 46.

[0112] exist Figure 3In the rod face 14 shown in (D), the first layer 36 is composed of SUS (stainless steel sheet) with a thickness of 0.2 mm.

[0113] The second layer 38 is composed of an elastic adhesive 42 with a thickness of 0.2±0.1mm (hardness A87 degrees on a hardness tester). The second layer 38 is bonded to the first layer 36 and the third layer 40 by the adhesive force of the elastic adhesive 42.

[0114] The third layer 40 is composed of titanium alloy with a thickness of more than 2.0 mm and less than 5.0 mm.

[0115] exist Figure 3 In the rod face 14 shown in (E), the first layer 36 is configured to include a SUS (stainless steel sheet) with a thickness of 0.2 mm. As an alternative to SUS (stainless steel sheet), a titanium sheet with a thickness of 0.4 mm or an aluminum sheet with a thickness of 0.6 mm can be used, for example.

[0116] The second layer 38 consists of a urethane sheet with a thickness of 0.1 mm (hardness A90 on a hardness tester).

[0117] The third layer 40 is composed of titanium alloy with a thickness of more than 2.0 mm and less than 5.0 mm.

[0118] The second layer 38 is bonded to the SUS (stainless steel sheet) of the first layer 36 by epoxy adhesive 44A with a thickness of 0.25 mm, and is bonded to the titanium alloy of the third layer 40 by epoxy adhesive 44B with a thickness of 0.25 mm.

[0119] Therefore, the first layer 36 is configured to contain epoxy adhesive 44A, and the third layer 40 is configured to contain epoxy adhesive 44B.

[0120] exist Figure 3 In the bar face 14 shown in (F), the first layer 36 is configured to include a SUS (stainless steel sheet) with a thickness of 0.2 mm.

[0121] The second layer 38 consists of double-sided adhesive tape (foaming agent) 46 with a thickness of 0.25mm.

[0122] The double-sided tape 46 of the second layer 38 is bonded to the first layer 36 by epoxy adhesive 44A with a thickness of 0.25 mm, and is bonded to the third layer 40 by epoxy adhesive 44B with a thickness of 0.25 mm.

[0123] The third layer 40 is composed of titanium alloy with a thickness of more than 2.0 mm and less than 5.0 mm.

[0124] Therefore, the first layer 36 is configured to contain epoxy adhesive 44A, and the third layer 40 is configured to contain epoxy adhesive 44B.

[0125] Alternatively, the second layer 38 may be composed solely of acrylic foam substrate, urethane foam substrate, polypropylene substrate, or polyester substrate after removing the adhesive components used in the double-sided tape 46.

[0126] In this example, epoxy adhesives 44A and 44B are used to enhance the adhesive strength of the double-sided tape 46. If it is not necessary to enhance the adhesive strength of the double-sided tape 46, epoxy adhesives 44A and 44B can be omitted.

[0127] Next, when describing the manufacturing method of the golf club head 10A according to this embodiment, as follows... Figure 2 (A) and Figure 3 As shown in (A) to (F), firstly, the golf club head 10A is manufactured except for the first layer 36 and the second layer 38 in the clubface 14.

[0128] Next, the second layer 38 is installed overlapping the third layer 40 on the rod face 14, and then the first layer 36 is installed overlapping the second layer 38.

[0129] The second layer 38 and the first layer 36 can be installed using elastic adhesive 42, double-sided tape 46, and epoxy adhesives 44A and 44B as described above. For example, when using thermosetting adhesives as epoxy adhesives 44A and 44B, the epoxy adhesives 44A and 44B are cured by hot pressing with the second layer 38 and the first layer 36 overlapped on the third layer 40.

[0130] Alternatively, when the outermost layer is CFRP, the CFRP can be cured first (150°C, 60 minutes), and then bonded using an adhesive. To make the cured CFRP conform to the shape of the innermost layer, it can also be heated at 120°C for 60 minutes.

[0131] In addition, such as Figure 2 As shown in (A), the outer surface of the first layer 36 (rod surface 1402) is higher than the outer surface of the third layer 40 by an amount corresponding to the thickness of the first layer 36 and the second layer 38, and an annular step is formed by the outer peripheral surfaces of the first layer 36 and the second layer 38 relative to the outer surface of the third layer 40.

[0132] Therefore, in order to eliminate the step, after bonding a ring-shaped synthetic resin 48 with the same thickness as the step between the outer peripheral surfaces of the first layer 36 and the second layer 38 and the outer surface of the third layer 40, the outer peripheral part of the first layer 36 and the synthetic resin 48 are ground to connect the outer surface of the third layer 40 with the outer surface of the first layer 36 (rod surface 1402) with a smooth curved surface.

[0133] Furthermore, the outer periphery of the outer surface of the first layer 36 (clubface surface 1402), the curved surface of the synthetic resin 48, and the outer surface of the third layer 40 are coated in a ring shape (not shown). By performing such a coating, the steps are concealed, and the appearance of the golf club head 10A is improved.

[0134] In this way, a golf club head 10A is manufactured with a face 14 having a first layer 36, a second layer 38, and a third layer 40.

[0135] Alternatively, instead of setting such a synthetic resin 48, it can be as follows: Figure 2 As shown in (B), in order to eliminate the annular step portions of the first layer 36 and the second layer 38 formed on the outer surface of the third layer 40, the steps are concealed by processing these portions of the first layer 36 and the second layer 38 into conical surfaces and applying a coating 49 to the surface of the conical surfaces, thereby improving the appearance of the golf club head 10A.

[0136] Next, the effects will be explained.

[0137] In this embodiment, when the tensile strengths of the first layer 36, the second layer 38, and the third layer 40 constituting the clubface 14 are set as material strengths S1, S2, and S3 respectively, the golf club head 10A has S3 ≥ S1 > S2.

[0138] Therefore, when the ball is struck using the clubface surface 1402, the first layer 36, the second layer 38, and the third layer 40 constituting the clubface 14 deform. However, since the soft second layer 38, which has the lowest tensile strength, is sandwiched between the hard first layer 36 and the second layer 38, which have high tensile strength, the clubface 14 deforms within an elastic deformation range. Therefore, the first layer 36 is more likely to deform as an extended surface rather than as a point, which is beneficial to increasing the contact area between the clubface surface 1402 and the ball and ensuring a longer contact time between the clubface surface 1402 and the ball.

[0139] Here, the deformation of the second layer 38 within the elastic deformation does not refer to the deformation of the clubface 14 within the range where no plastic deformation occurs, but rather to the deformation in which the shape of the clubface 14 roughly recovers to its shape before deformation at the point when the ball hit by the clubface 1402 leaves the clubface 1402.

[0140] In other words, at the moment when the ball, after being struck by the clubface 1402, leaves the clubface 1402, the shape of the clubface 14 is still significantly deformed, and the clubface 14 is in a state that deviates significantly from its original shape and has not returned to its original shape. Such deformation is not within the scope of elastic deformation.

[0141] When the rod face 14 undergoes deformation that is not within the elastic range, there is a disadvantage of large energy loss and a decrease in initial velocity.

[0142] Thus, when the ball is struck, if the contact area and contact time between the ball and the clubface 1402 increase, the backspin of the ball decreases due to the rebound effect, resulting in a high takeoff angle and low spin, and increasing the flight distance of the ball.

[0143] In addition, since the shaft face 14 deforms within the elastic deformation, the shaft face 14 flexes over a large area. Therefore, the initial velocity of the ball becomes high over a large area of ​​the shaft face surface 1402, which is beneficial to expanding the high initial velocity region.

[0144] In addition, since the stress during impact is mitigated by the soft second layer 38, the stress generated in the third layer 40 can be mitigated, which helps to ensure the durability of the clubface 14 over a large area of ​​the clubface surface 1402.

[0145] In addition, the soft second layer 38 makes the volume, height, and reverberation of the impact sound within a comfortable range for golfers. As a result, the impact feel is moderately softened, which helps to optimize the impact feel over a large area of ​​the clubface surface 1402.

[0146] Here, the tensile strength, hardness, tensile modulus of elasticity, and wall thickness of layer 1 (36), layer 2 (38), and layer 3 (40) are explained.

[0147] In this invention, it is important to ensure the durability of the golf club head while allowing the soft layer (second layer 38) within the elastic deformation to deform moderately in a planar manner. As a result, the high initial velocity region can be expanded without initial velocity descent, the flight distance can be extended with a high launch angle and moderately little backspin, and a soft hitting feel can also be achieved.

[0148] To ensure durability, tensile strength needs to be increased. Since the outermost layer (layer 1, 36), the innermost layer (layer 3, 40), and the middle layer (layer 2, 38) experience greater deformation (tensile and compressive stress) upon impact compared to the middle layer, high-strength materials are required.

[0149] On the other hand, within the elastic deformation, the soft layer (second layer 38) that deforms in a planar manner must be moderately soft. For example, if it is too soft, it will cause energy loss and lead to a decrease in initial velocity. In order to make the soft layer (second layer 38) deform in a planar manner within the elastic deformation, hardness becomes an important factor.

[0150] In addition, the bending stiffness (bending stiffness (EI) = longitudinal Young's modulus (E) × second moment of section (I)), where the longitudinal Young's modulus (E) is the tensile modulus of elasticity in this specification.

[0151] In addition, bending stiffness is also important, as the tensile modulus of elasticity of various materials is related to the wall thickness.

[0152] That is, the four factors of tensile strength, hardness, tensile modulus of elasticity and wall thickness are intricately intertwined, and proper and appropriate configuration is the focus of the golf club head of the present invention.

[0153] Next, refer to Figure 8 , Figure 9 The first and second modifications of the first embodiment will be described.

[0154] The first and second variations are variations designed to ensure that the thickness of the second layer 38 is a certain size.

[0155] In addition, such as Figure 8 (B) Figure 9 As shown in (B), with Figure 2 (B) Similarly, a coating 49 was applied to remove the annular step portions of the first layer 36 and the second layer 38 formed on the outer surface of the third layer 40.

[0156] like Figure 8 As shown in (A) and (B), in the first modified example, the first layer 36 (first bar face member 30) constituting the bar face surface 1402 is made of CFRP with a thickness of 0.75 mm, the second layer 38 (second bar face member 32) is made of elastic adhesive 42 (or hot melt adhesive), and the third layer 40 (bar face plate 34) is made of 6-4Ti rolled plate.

[0157] On the front surface of the third layer 40 (6-4Ti rolled plate), i.e. the front surface of the rod face plate portion 34 facing the second layer 38, there are a plurality of cylindrical protrusions 3402 with a height of 0.25 mm and a diameter of 2 mm that protrude toward the second layer 38 at 15 mm intervals in the heel direction and crown-bottom direction.

[0158] Furthermore, by abutting the tops of the plurality of protrusions 3402 against the rear surface of the first layer 36 (CFRP), a gap of 0.25 mm is ensured between the front surface of the third layer 40 (6-4Ti rolled plate) and the rear surface of the first layer 36 (CFRP). Thus, a second layer 38 with a thickness of 0.25 mm is formed by filling the gap with elastic adhesive 42.

[0159] exist Figure 9 In the second variation shown, the structure of the first layer 36, the second layer 38, and the third layer 40 is the same as that of the first variation.

[0160] like Figure 9As shown in (A) and (B), in the second modified example, on the rear surface of the first layer 36 (CFRP) with a thickness of 0.75 mm, that is, the rear surface of the first rod face member 30 and the second layer 38 facing each other, there are a plurality of cylindrical protrusions 3002 with a height of 0.25 mm and a diameter of 1 mm that protrude toward the second layer 38 at intervals of 15 mm in the heel direction and crown-bottom direction.

[0161] Furthermore, by abutting the tops of the plurality of protrusions 3002 against the front surface of the third layer 40 (6-4Ti rolled plate), a gap of 0.25 mm is ensured between the front surface of the third layer 40 (6-4Ti rolled plate) and the rear surface of the first layer 36 (CFRP). Thus, a second layer 38 with a thickness of 0.25 mm is formed by filling the gap with elastic adhesive 42.

[0162] In either of the first or second variations, the shape of the protrusions 3402 and 3002 is not limited to cylindrical, as long as a gap can be ensured between the front surface of the third layer 40 (6-4Ti rolled plate) and the rear surface of the first layer 36 (CFRP).

[0163] According to such first and second variations, by setting a simple structure with multiple protrusions 3402 and 3002, it is beneficial to ensure that the thickness of the elastic adhesive 42 constituting the second layer 38 is a certain size.

[0164] (Second Implementation)

[0165] Next, refer to Figure 4 (A) The second embodiment will be described.

[0166] Furthermore, in the following embodiments, the same reference numerals are used to mark the same parts and components as in the first embodiment, and their descriptions are omitted; the different parts are described in detail.

[0167] like Figure 4 As shown in (A), a thin-walled portion 4002, which is thinner than other portions, is formed in the third layer 40.

[0168] The thin-walled portion 4002 is composed of a recess 4004 formed in an open shape on the front surface of the third layer 40 facing the first layer 36.

[0169] The first layer 36 is composed of either a 0.2 mm thick SUS (stainless steel sheet) or a 0.75 mm thick CFRP (prepreg sheet).

[0170] The second layer 38 is configured by filling the recess 4004.

[0171] The third layer 40 is composed of titanium alloy with a thickness of more than 2.0 mm and less than 5.0 mm.

[0172] In detail, the second layer 38 is formed by overlapping a urethane sheet 50A with a thickness of 0.3 mm (hardness A90 degree) that is formed with a shape and wall thickness corresponding to the recess 4004 and fills the recess 4004, and a urethane sheet 50B with a thickness of 0.1 mm (hardness A90 degree) that is disposed on the front surface of the third layer 40 containing the recess 4004.

[0173] Furthermore, the second layer 38 is bonded to the SUS (stainless steel sheet) or CFRP of the first layer 36 by an epoxy adhesive 44A with a thickness of 0.25 mm, and is bonded to the titanium alloy of the third layer 40 by an epoxy adhesive 44B with a thickness of 0.13 mm.

[0174] Therefore, the first layer 36 and the third layer 40 are configured to contain epoxy adhesives 44A and 44B.

[0175] According to the second embodiment, the same effect as the first embodiment can be achieved. By providing a recess 4004 on the front surface of the third layer 40, a thin-walled portion 4002 that locally thins the wall thickness of the third layer 40 can be formed, and an uneven wall thickness structure can be formed on the rod surface 14.

[0176] Therefore, for example, by forming an annular thin-walled portion 4002 around the center of the shaft face 1402, the deflection of the shaft face 14 is increased, which is beneficial to achieving higher initial ball velocity and greater flight distance.

[0177] Alternatively, a recess 4004 can be provided on the rear surface of the third layer 40 to form an uneven wall thickness structure on the shaft face 14. However, if a recess 4004 is provided on the front surface of the third layer 40 as in the embodiment to form an uneven wall thickness structure on the shaft face 14, the surface deformation can be increased in the part near the impact surface compared to providing a recess on the rear surface of the third layer 40. This is beneficial for expanding the high initial velocity region, ensuring the rebound effect, and improving durability.

[0178] Furthermore, the shape and number of the thin-walled portions 4002 that constitute the uneven wall thickness structure are not limited.

[0179] (Third implementation)

[0180] Next, refer to Figure 4 (B) The third embodiment will be described.

[0181] The third embodiment is a variation of the second embodiment. The difference from the second embodiment is that the portion of the front surface of the third layer 40, except for the recess 4004, overlaps directly with the first layer 36 without being separated from the second layer 38.

[0182] In detail, the first layer 36 is composed of either a 0.2 mm thick SUS (stainless steel sheet) or a 0.75 mm thick CFRP (prepreg sheet).

[0183] The second layer 38 is composed of a urethane sheet 50C with a thickness of 0.2 mm (hardness A90 degrees on a hardness tester) that corresponds to the shape of the recess 4004 and is filled in the recess 4004.

[0184] The third layer 40 is composed of titanium alloy with a thickness of more than 2.0 mm and less than 5.0 mm.

[0185] In detail, the front surface of the second layer 38 and the front surface of the third layer 40, excluding the recess 4004, are bonded to the SUS (stainless steel sheet) or CFRP of the first layer 36 by an epoxy adhesive 44A with a thickness of 0.25 mm, and the portion of the second layer 38 that fills the recess 4004 is bonded to the recess 4004 (titanium alloy) of the third layer 40 by an epoxy adhesive 44B with a thickness of 0.13 mm.

[0186] That is, the first layer 36 is configured to contain epoxy adhesive 44A, and the third layer 40 is configured to contain epoxy adhesive 44B.

[0187] Therefore, the front surface of the third layer 40, excluding the recess 4004, directly overlaps with the first layer 36.

[0188] This third embodiment can achieve roughly the same effect as the second embodiment.

[0189] (Fourth implementation)

[0190] Next, refer to Figure 5 (A) The fourth embodiment will be described.

[0191] Furthermore, in the fourth embodiment, the mutual mounting structure of the first layer 36, the second layer 38, and the third layer 40, i.e., the mutual mounting structure of the first bar face member 52, the second bar face member 54, and the third bar face member 56 described later, is the same as in the first embodiment, and therefore its description is omitted.

[0192] The golf club head 10B of the fourth embodiment is configured to include a hollow club head body 12B, a plate-shaped first club face member 52, a plate-shaped second club face member 54, and a plate-shaped third club face member 56.

[0193] The clubhead body 12B includes: a clubface outer periphery 60 with an opening 58 provided on the outer periphery of the clubface 14; and a crown 16, a bottom 18, and a side 20 connected to the clubface outer periphery 60.

[0194] The club head body 12B is similar to the club head body 12B of the first embodiment, and is made of metal material or fiber reinforced resin material (FRP), or a combination of metal material and fiber reinforced resin material.

[0195] In addition, when using titanium alloy as the metal material constituting the clubhead body 12B, for example, 8-1-1Ti can be used as a titanium alloy.

[0196] The outer periphery of the clubface 60 is configured to include a frame-shaped outer periphery plate 62 constituting the outer periphery of the clubface surface 1402, a frame-shaped protruding plate 64 protruding from the inner periphery of the frame-shaped outer periphery plate 62 toward the interior of the clubhead body 12B, and a frame-shaped inner periphery plate 66 protruding inward from the top of the frame-shaped protruding plate 64.

[0197] The clubface 14 of the golf club head 10B is composed of a first layer 36 constituting the clubface surface 1402, a second layer 38 located on the side of the first layer 36 opposite to the clubface surface 1402, and a third layer 40 located on the side of the second layer 38 opposite to the first layer 36.

[0198] The third layer 40 is composed of a third face member 56, which is disposed on the inner side of the outer periphery 60 of the face and inside the head body 12B. Specifically, the outer periphery end face of the third face member 56 is welded to the top end face of the inner periphery plate 66 of the outer periphery 60 of the face and grounded.

[0199] The third bar face member 56 is made of, for example, a rolled sheet or a metal material produced by forging. As such a metal material, a rolled sheet of 6-4Ti titanium alloy can be exemplified.

[0200] Furthermore, the material was chosen such that the strength (tensile strength) of the third face member 56, made of 6-4Ti rolled plate, is greater than the strength (tensile strength) of the clubhead body 12B, made of 8-1-1Ti (cast material). This is to maintain the durability of the clubface 14 to prevent damage upon impact.

[0201] A weld bead receiving space 68 is provided across the outer surface of the protruding plate portion 64 located on the side that is away from the interior of the club head body 12B and the outer surface of the outer periphery of the third club face member 56. The weld bead B generated when the outer periphery of the third club face member 56 is grounded and welded to the top end face of the inner peripheral plate portion 66 of the club face outer periphery portion 60 is contained in the weld bead receiving space 68.

[0202] The second layer 38 is composed of the second bar face member 54, which is installed on the inner side of the outer peripheral plate 62 of the outer peripheral portion 60 of the bar face, overlapping with the surface of the third bar face member 56.

[0203] The first layer 36 is composed of the first bar face member 52, which is installed on the inner side of the outer peripheral plate portion 62 of the bar face outer periphery 60 and overlaps with the surface of the second bar face member 54. The bar face surface 1402 is composed of the surface of the outer peripheral plate portion 62 of the bar face outer periphery 60 and the surface of the first bar face member 52.

[0204] The weld bead receiving space 68 is covered by the second bar face member 54 and the first bar face member 52.

[0205] Furthermore, it is permissible to fill the weld bead receiving space 68 with resin, adhesive, etc., before covering it with the second bar surface member 54.

[0206] Alternatively, a protrusion with a shape corresponding to the weld bead receiving space 68 can be pre-formed on the second bar surface member 54, and the protrusion can be used to fill the weld bead receiving space 68.

[0207] Alternatively, resin or the like can be filled into the annular gap 70 between the outer peripheral end face of the first face member 52 and the second face member 54 and the outer peripheral plate portion 62, or the gap 70 can be hidden by coating or the like, thereby improving the appearance of the golf club head 10B.

[0208] In addition, such as Figure 5 As shown in (B), when the outer peripheral end faces of the first face member 52 and the second face member 54 abut against the outer peripheral plate portion 62 without gap and a boundary line is formed between them, the boundary line can also be hidden by covering the boundary line with paint 71, etc., to improve the appearance of the golf club head 10B.

[0209] According to the fourth embodiment, the same effect as the first embodiment can be achieved. Since the weld reception space 68, which contains the weld B formed by welding the third face member 56 to the club head body 12B, is covered by the second face member 54 and the first face member 52, the grinding operation of the weld B that was previously required can be omitted, which is beneficial to reducing the manufacturing cost of the golf club head 10B.

[0210] Alternatively, it is also possible to weld without providing a recessed portion towards the hollow portion 22 at the welding point between the third face member 56 and the head body 12B. However, if the weld bead B protrudes outward, grinding (machining) of the weld bead B is required, which would increase manufacturing costs. Therefore, in the fourth embodiment, a structure is designed to completely accommodate the weld bead B using the weld bead receiving space 68, thus eliminating the need for grinding the weld bead B.

[0211] Furthermore, the combination of the uneven wall thickness structure of the second and third embodiments in the fourth embodiment is arbitrary.

[0212] In addition, in the fourth embodiment, the third face member 56 and the head body 12B are made of different metal materials, and the third face member 56 can be made of a metal material with higher strength than the head body 12B.

[0213] For example, the third bar face component 56 can be made of 6-4Ti rolled plate, and the bar head body 12B can be made of 8-1-1Ti.

[0214] In addition, in the fourth embodiment, the third face member 56 and the head body 12B are made of different materials, and the third face member 56 can be made of a material with higher strength than the head body 12B.

[0215] For example, the third face member 56 can be made of 6-4Ti rolled plate, and the head body 12B can be made of CFRP.

[0216] Alternatively, in the fourth embodiment, the weld bead receiving space 68 may not be provided, and the weld bead B formed by welding the third face member 56 to the club head body 12B may be ground in the same manner as in the past. The welded part of the third face member 56 and the club head body 12B may be covered by the second face member 54 and the first face member 52. However, if it is set as in the fourth embodiment, it is beneficial to reduce the manufacturing cost.

[0217] Next, refer to Figure 10 , Figure 11 The first and second modifications of the fourth embodiment will be described.

[0218] The first and second variations are variations designed to ensure that the thickness of the second layer 38 is a certain size.

[0219] In addition, in the following Figure 10 , Figure 11 In order to simplify the illustration, the weld bead B and weld bead receiving space 68 formed by welding the plate-shaped third bar face member 56 to the opening 58 of the bar head body 12B are omitted from the illustration. Additionally, as... Figure 10 (B) Figure 11 As shown in (B), with Figure 5 (B) Similarly, a coating 71 was applied to cover the boundary line between the outer peripheral end face of the first bar face member 52 and the second bar face member 54 and the outer peripheral plate portion 62.

[0220] like Figure 10As shown in (A) and (B), in the first modified example, the first layer 36 (first bar face member 52) constituting the bar face surface 1402 is made of CFRP with a thickness of 0.75 mm, the second layer 38 (second bar face member 54) is made of elastic adhesive 42 (or hot melt adhesive), and the third layer 40 (third bar face member 56) is made of 6-4Ti rolled plate.

[0221] On the front surface of the third layer 40 (6-4Ti rolled plate), that is, the front surface of the third rod surface member 56 facing the second layer 38, there are multiple cylindrical protrusions 5602 with a height of 0.25 mm and a diameter of 2 mm that protrude toward the second layer 38 at 15 mm intervals in the heel direction and crown-bottom direction.

[0222] Furthermore, by abutting the tops of the plurality of protrusions 5602 against the rear surface of the first layer 36 (CFRP), a gap of 0.25 mm is ensured between the front surface of the third layer 40 (6-4Ti rolled plate) and the rear surface of the first layer 36 (CFRP). Thus, a second layer 38 with a thickness of 0.25 mm is formed by filling the gap with elastic adhesive 42.

[0223] exist Figure 11 In the second variant shown in (A) and (B), the structure of the first layer 36, the second layer 38, and the third layer 40 is the same as that of the first variant.

[0224] like Figure 11 As shown in (A) and (B), in the second modified example, on the rear surface of the first layer 36 (CFRP) with a thickness of 0.75 mm, that is, the rear surface of the first rod face member 52 and the second layer 38 facing each other, there are a plurality of cylindrical protrusions 5202 with a height of 0.25 mm and a diameter of 1 mm that protrude toward the second layer 38 at intervals of 15 mm in the heel direction and crown-bottom direction.

[0225] By abutting the tops of the plurality of protrusions 5202 against the front surface of the third layer 40 (6-4Ti rolled plate), a gap of 0.25 mm is ensured between the front surface of the third layer 40 (6-4Ti rolled plate) and the rear surface of the first layer 36 (CFRP). Thus, a second layer 38 with a thickness of 0.25 mm is formed by filling the gap with elastic adhesive 42.

[0226] In either of the first and second variations, the shapes of the protrusions 5602 and 5202 are not limited to cylindrical, as long as a gap can be ensured between the front surface of the third layer 40 (6-4Ti rolled plate) and the rear surface of the first layer 36 (CFRP).

[0227] According to these first and second variations, by setting up a simple structure with multiple protrusions 5602 and 5202, it is beneficial to ensure that the thickness of the elastic adhesive 42 constituting the second layer 38 is a certain size.

[0228] Furthermore, in the fifth embodiment described later, the same structure as the first and second variations described above can also be adopted.

[0229] (Fifth implementation)

[0230] Next, refer to Figure 6 The fifth embodiment will be described.

[0231] Furthermore, in the fifth embodiment, the mutual mounting structure of the first layer 36, the second layer 38, and the third layer 40, i.e., the mutual mounting structure of the first bar face member 72, the second bar face member 74, and the third bar face member 76 described later, is the same as in the first embodiment, and therefore its description is omitted.

[0232] The golf club head 10C is composed of a hollow club head body 12C, a plate-shaped first face member 72, a plate-shaped second face member 74, and a plate-shaped third face member 76.

[0233] The clubhead body 12C has a crown 16, a bottom 18 and a side 20, and also has an opening 78 obtained by cutting off the shaft face 14, the portion of the crown 16 near the shaft face 14, the portion of the bottom 18 near the shaft face 14 and the portion of the side 20 near the shaft face 14.

[0234] The clubhead body 12C is made of metal or fiber-reinforced resin (FRP), or a combination of metal and fiber-reinforced resin.

[0235] In addition, when using titanium alloy as the metal material constituting the clubhead body 12C, 8-1-1Ti as a titanium alloy can be exemplified.

[0236] The face 14 of the golf club head 10C is composed of a first layer 36 constituting the face surface 1402, a second layer 38 located on the side of the first layer 36 opposite to the face surface 1402, and a third layer 40 located on the side of the second layer 38 opposite to the first layer 36.

[0237] The third layer 40 is composed of a third face member 76, which has a third face body 7602 corresponding to the face 14 and a third flange 7604 protruding from the outer periphery of the third face body 7602 toward the head body 12C.

[0238] The third bar face member 76 is made of, for example, a rolled sheet or a metal material produced by forging. As such a metal material, a rolled sheet of 6-4Ti titanium alloy can be exemplified.

[0239] Furthermore, the material was designed such that the strength (tensile strength) of the third face member 76 is greater than the strength (tensile strength) of the clubhead body 12C.

[0240] The top end face of the third flange 7604 is grounded and welded to the top end face of the crown 16 forming the opening 78, the top end face of the bottom 18, and the top end face of the side 20.

[0241] A weld bead receiving space 80 is provided on the outer periphery of the front part of the third flange 7604, the outer periphery of the crown 16, the outer periphery of the bottom 18, and the outer periphery of the side part 20, which extends from the inside of the rod head body 12C. The weld bead B generated during welding is received in the weld bead receiving space 80.

[0242] The second layer 38 is composed of a second face member 74, which includes: a second face body 7402, which is mounted overlapping with a third face body 7602; and a second flange 7404, which protrudes from the outer periphery of the second face body 7402 toward the head body 12C and covers the weld bead receiving space 80 and is mounted overlapping with the third flange 7604 and the portion of the crown 16 near the opening 78, the portion of the bottom 18 near the opening 78, and the portion of the side 20 near the face 14.

[0243] The first layer 36 is composed of a first face member 72, which has a first face body 7202 that overlaps with the second face body 7402 and a first flange 7204 that protrudes from the outer periphery of the first face body 7202 toward the head body 12C and overlaps with the second flange 7404.

[0244] Therefore, the weld bead receiving space 80 is covered by the second bar face member 74 and the first bar face member 72.

[0245] Furthermore, the first flange 7204, the second flange 7404, and the third flange 7604 correspond to the portions of the crown 16 that are cut off due to the opening 78 near the stem face 14, the portion of the bottom 18 that is near the stem face 14, and the portion of the side portion 20 that is near the stem face 14.

[0246] Furthermore, operations such as filling the weld bead receiving space 80 with resin before covering it with the second bar surface member 74 are optional.

[0247] Alternatively, a protrusion with a shape corresponding to the weld bead receiving space 80 can be pre-formed on the second bar surface member 74, and the protrusion can be used to fill the weld bead receiving space 80.

[0248] In addition, such as Figure 6 As shown, the first flange 7204 (first layer 36) and the second flange 7404 (second layer 38) are higher than the outer surface of the club head body 12C by an amount corresponding to the thickness of the first layer 36 and the second layer 38. A ring-shaped step is formed by the top end faces of the first flange 7204 and the second flange 7404 relative to the outer surface of the club head body 12C.

[0249] Therefore, in order to eliminate the step, after bonding a synthetic resin 82 of the same thickness as the step between the top end faces of the first flange 7204 and the second flange 7404, the outer surface of the third layer 40 and the outer surface of the rod head body 12C, the first flange 7204 and the synthetic resin 82 are ground to connect the outer surface of the rod head body 12C and the outer surface of the first flange 7204 with a smooth curved surface.

[0250] Furthermore, a coating is applied to the outer surface of the first flange 7204, the curved surface of the synthetic resin, and the outer surface of the clubhead body 12C. This coating conceals the steps and improves the appearance of the golf clubhead 10C.

[0251] According to the fifth embodiment, the same effect as the first embodiment can be achieved. Since the weld reception space 80, which contains the weld B formed by welding the third face member 76 to the club head body 12C, is covered by the second face member 74 and the first face member 72, the grinding operation of the weld B that was previously required can be omitted, which is beneficial to reducing the manufacturing cost of the golf club head 10C.

[0252] Furthermore, the combination of the uneven wall thickness structure of the second and third embodiments in the fifth embodiment is arbitrary.

[0253] In addition, in the fifth embodiment, the third face member 76 and the head body 12B are made of different metal materials, and the third face member 76 can be made of a metal material with higher strength than the head body 12B.

[0254] For example, the third face member 76 can be made of 6-4Ti rolled plate, and the head body 12C can be made of 8-1-1Ti.

[0255] In addition, in the fifth embodiment, the third face member 76 and the head body 12B are made of different materials, and the third face member 76 can be made of a material with higher strength than the head body 12B.

[0256] For example, the third face member 76 can be made of 6-4Ti rolled plate, and the head body 12C can be made of CFRP.

[0257] (Sixth implementation)

[0258] Next, refer to Figure 7 The sixth embodiment will be described.

[0259] The golf club head 10D of the sixth embodiment is a variation of the fifth embodiment. It is provided that: no weld bead receiving space 80 is provided, and the weld bead B formed on the outside of the third face member 76 and the club head body 12D by welding the third face member 76 and the club head body 12D is ground in the same way as in the past. The welded part of the third face member 76 and the club head body 12D is covered by the second face member 74 and the first face member 72.

[0260] Furthermore, in the sixth embodiment, the mutual mounting structure of the first layer 36, the second layer 38, and the third layer 40, i.e., the mutual mounting structure of the first rod face member 72, the second rod face member 74, and the third rod face member 76, is the same as in the fifth embodiment, and therefore its description is omitted.

[0261] That is, such as Figure 7 As shown in (A) and (B), by welding the third face member 76 and the head body 12D, weld B is formed on the inner side (hollow part 22 side) of the third face member 76 and the head body 12D, and on the outer side (opposite to the hollow part 22 side) of the third face member 76 and the head body 12D.

[0262] Next, as Figure 7 As shown in (C), the weld B formed on the outer side (opposite to the hollow part 22) of the third face member 76 and the head body 12D is ground, and the outer side of the third face member 76 and the outer side of the head body 12D are connected by a smooth curved surface.

[0263] Next, as Figure 7 As shown in (D), after the second layer 38 (second layer 74) is installed overlapping the third layer 40 (third face member 76), the first layer 36 (first face member 72) is installed overlapping the second layer 38 (second face member 74) with the second face member 74.

[0264] At this time, similar to the fifth embodiment, since an annular step formed by the top end faces of the first flange 7204 and the second flange 7404 is formed relative to the outer surface of the club head body 12D, in order to eliminate the step, after bonding a synthetic resin 82 of the same thickness as the step between the top end faces of the first flange 7204 and the second flange 7404, the outer surface of the third layer 40 and the outer surface of the club head body 12D, the first flange 7204 and the synthetic resin 82 are ground to connect the outer surface of the club head body 12D and the outer surface of the first flange 7204 with a smooth curved surface.

[0265] Furthermore, a coating is applied to the outer surface of the first flange 7204, the curved surface of the synthetic resin, and the outer surface of the clubhead body 12D. This coating conceals the steps and improves the appearance of the golf clubhead 10D.

[0266] Alternatively, synthetic resin 82 can be used instead, such as... Figure 7 As shown in (E), in order to eliminate the annular step portion on the top end face of the first flange 7204 and the second flange 7404 formed on the outer surface of the clubhead body 12D, the step is hidden by processing the top portion of the first flange 7204 and the second flange 7404 into a conical surface and applying a coating 83 to the surface of the conical surface, thereby improving the appearance of the golf clubhead 10D.

[0267] In this way, it achieves the same effect as the fifth implementation method.

[0268] Next, experimental examples of the present invention will be described.

[0269] Figures 12 to 15 This is a diagram showing the experimental results of the golf club head of the present invention.

[0270] For each experimental example, golf club heads were made as test samples. The following five evaluation items were measured and the index (evaluation score) was calculated. The total score of the five indexes was also calculated.

[0271] (1) High initial velocity region (sweet area)

[0272] Centered on the center point Pc of the shaft face 1402, 45 equally spaced points in the heel and crown directions are set as hitting points Pi.

[0273] A specialized swing robot was used to strike a golf club at 45 different points (Pi), and the initial velocity of the golf ball was measured by a measuring device. The clubhead speed was 40 m / s.

[0274] Interpolating the initial velocity data from 45 impact points resulted in an indexation of the area of ​​the high initial velocity region on the clubface surface 1402, which represents over 98% of the maximum initial velocity of the golf ball. Furthermore, for data from impact points higher than the center point Pc (crown 16 side) and lower than the center point Pc (bottom 18 side), the weighting of the data from the upper impact point (crown 16 side) was increased to match the actual impact point positions used by golfers.

[0275] Data in the high initial velocity region are expressed using an index of 100, with the measurement results of the golf club head from Experiment 1 set as 100. A higher index indicates a better evaluation.

[0276] (2) Takeoff angle

[0277] The takeoff angle was measured in an actual impact test at the aforementioned impact point location.

[0278] The index of Experiment Example 1 is set to 100. The larger the index, the greater the takeoff angle, which indicates a better evaluation.

[0279] (3) Spin

[0280] Based on the spin (backspin) obtained from the actual impact test at the aforementioned impact point Pi, the exponent of Experimental Example 1 was set to 100. The larger the exponent, the smaller the spin, indicating a better evaluation.

[0281] (4) Impact sensation

[0282] Regarding the feel of the shot, the sound of the ball hitting the clubhead is dominant. Generally speaking, a softer feel is preferred if the echo of the shot is made shorter and lower in pitch, which will result in higher ratings from golfers.

[0283] The evaluation method for the impact feel is as follows.

[0284] A dedicated swing robot is used to swing a golf club at a clubhead speed of 40 m / s with the center point Pc as the striking point. The sound of the golf ball hitting is measured by a noise meter, and the vibration waveform data of the sound of the ball hitting is sampled and recorded at a predetermined sampling period.

[0285] Next, the residual response parameter T is calculated.

[0286] The reverberation parameter T is a parameter that represents the degree of attenuation of the impact sound. In the calculation of the reverberation parameter T, firstly, regarding the recorded vibration waveform data, the earliest sampled data (starting point data) on the time axis is used as the reference number, and based on this number, a block group α is generated by dividing the sound pressure vibration waveform into predetermined sample numbers, such as 100 sample numbers.

[0287] Furthermore, for each block Ak in the block group α, the sum of squares of the vibration waveform level is calculated, and for each block, the logarithm of the sum of squares is calculated (hereinafter referred to as the block value).

[0288] Furthermore, the block with the largest sound pressure level (SPL) value is extracted from each block group α as the starting block. A value lower than the SPL value of this starting block (30 dB in this embodiment) is set as the ending block value. From the blocks following the starting block, the ending block whose block value first becomes lower than the ending block value is extracted.

[0289] Furthermore, the time width between the earliest sampled data of each of these start and end blocks on the time axis is set as the reverberation parameter T.

[0290] Therefore, the reverberation parameter T corresponds to the reverberation time of the impact sound. The shorter the reverberation parameter T, the shorter the reverberation, the softer the impact feel, and the higher the evaluation of the impact feel.

[0291] In this case, the data on the feel of impact is expressed using an exponent that sets 1 / T, the reciprocal of the reverberation parameter T of the golf clubhead (equivalent to Comparative Example 1), to 100. The larger the exponent, the better the evaluation of the feel of impact.

[0292] Furthermore, the method for calculating the aforementioned reverberation parameter T can be, for example, the method described in Japanese Patent No. 4840106, but it is not limited to how the reverberation time of the impact sound is evaluated. The reverberation time of the impact sound can be obtained by various methods known in the past, and the impact feel can be evaluated.

[0293] In addition to calculating the reverberation parameters and reverberation time to evaluate the feel of the shot, one can also have a golfer actually swing the golf club to hit the ball and listen to the sound of the impact to evaluate the feel of the shot.

[0294] (5) Durability

[0295] On the clubface 1402 of the golf clubhead fixed to the shaft, a golf ball is repeatedly struck by an air cannon. The number of strikes required until deformation or damage to the clubface 1402 is measured and then exponentialized. The ball speed is set to 50 m / s. The point of impact is set to the center point Pc of the clubface 1402.

[0296] In this case, the result of the measurement of the golf club head, which is equivalent to the comparative example 1, is expressed as an index of 100. The larger the index, the better the evaluation.

[0297] (6) Total Score

[0298] The total score is the sum of the five indices: high initial velocity region, takeoff angle, backspin, impact feel, and durability.

[0299] The total score of Experiment Example 1, which is equivalent to the comparative example, is set to 500. The higher the total score, the better the evaluation.

[0300] The experimental conditions are explained.

[0301] Experimental Example 1 is a comparative example, corresponding to Patent Document 1 (Japanese Patent No. 4340177) listed in the prior art. It is a golf club head composed of a first metal plate on the clubface and a second metal plate that supports the first metal plate via multiple ribs.

[0302] Experimental Example 1 does not meet the requirements of claim 1 and is outside the scope of the present invention.

[0303] The specifications of each part of Experiment Example 1 are as follows.

[0304] Material of the clubhead body: Titanium alloy Ti-8Al-1Mo-1V

[0305] Material of the shaft face: Titanium alloy Ti-6Al-4V

[0306] Loft Angle: 10.5°

[0307] Lie Angle: 59°

[0308] club head weight 200g

[0309] 460cc clubhead volume

[0310] The golf club heads used in Experiments 2-25 are golf club heads corresponding to the present invention, and are hollow tee woods. Except for the parameters specified in each experiment, the following specifications are set to be common.

[0311] Loose angle of 10.5°

[0312] 59° base angle

[0313] club head weight 200g

[0314] 460cc clubhead volume

[0315] In addition, the golf club head used in Experimental Examples 2-25 is based on Embodiment 4 ( Figure 5 (A)) is composed of the structure.

[0316] Furthermore, in Experimental Example 2-25, the materials constituting layer 1 36, layer 2 38, and layer 3 40 are described in... Figures 12-15 .

[0317] Furthermore, when illustrating the general tensile strength of materials, titanium alloy (6-4Ti) is approximately 1047 MPa, CFRP (long fiber) is approximately 1250~2500 MPa, polyurethane is approximately 200~450 MPa, polycarbonate is approximately 65 MPa, and vinyl chloride is approximately 50 MPa, etc.

[0318] (Condition 1:) Figure 12 / Experimental Example 2-8)

[0319] In addition, in the following Figures 12-15 In the text, the symbol recorded in the column for tensile strength S3≥S1>S2 is... This indicates that the conditions for meeting the above tensile strength requirements are met, indicated by the symbol. This indicates that the above conditions for tensile strength are not met.

[0320] like Figure 12 As shown, Experimental Example 1 is a comparative example and is outside the scope of this invention.

[0321] Experimental Examples 2-8 all satisfy the requirements of claim 1, i.e., tensile strength S3≥S1>S2.

[0322] Experimental Examples 2-8 all satisfy the requirements of claims 1, 2, 3, 4, and 5.

[0323] In addition, Experimental Example 8, besides satisfying 1, 2, 3, 4, and 5, also satisfies the requirements of claim 6 (uneven wall thickness structure). Furthermore, the uneven wall thickness structure of Experimental Example 8 is similar to that of Embodiment 3 (…). Figure 4 (B) is the same.

[0324] Therefore, compared with Experiment 1 which is outside the scope of the present invention, Experiments 2-8 which are within the scope of the present invention exhibit superior performance in the high initial velocity region, takeoff angle, backspin, durability, impact feel, and overall score.

[0325] (Condition 2:) Figure 13 / Experimental Example 9-17)

[0326] Examples 9, 10, 13, 16, and 17 in Examples 9-17 do not meet the requirements of claim 1 and at least claim 2 (hardness of the first layer 36, the second layer 38, and the third layer 40) and are outside the scope of this invention.

[0327] The remaining experimental examples 11, 12, 14, and 15 satisfy the requirements of claim 1, and at least satisfy the requirements of claim 2.

[0328] In addition, Figure 13 In the experiment, the hardness M70 of the second layer 38 in Example 10 represents the Rockwell hardness.

[0329] Therefore, compared with experimental examples 9, 10, 13, 16, and 17 that do not at least meet the requirements of claim 2, experimental examples 11, 12, 14, and 15 that meet the requirements of claim 2 have superior performance in the high initial velocity region, takeoff angle, backspin, durability, impact feel, and overall score.

[0330] (Condition 3:) Figure 14 / Experimental Examples 18-21)

[0331] Experimental Examples 18 and 19 in Experimental Examples 18-21 satisfy the requirements of claim 1. On the other hand, they do not satisfy the requirements of the wall thickness of the second layer 38 in claim 4 (the wall thickness of the first layer 36, the second layer 38, and the third layer 40), and are outside the scope of the present invention.

[0332] The remaining experimental examples 20 and 21 satisfy the requirements of claim 1, and at least satisfy the requirements of claim 4.

[0333] Therefore, compared with experimental examples 18 and 19 that do not meet the requirements of claim 4, experimental examples 20 and 21 that meet the requirements of claim 4 have superior performance in the high initial velocity region, takeoff angle, backspin, durability, impact feel, and overall score.

[0334] (Condition 4:) Figure 15 / Experimental Examples 22-24)

[0335] Experimental Examples 22-24 vary the volume of the rod head, yet all satisfy the requirements of claims 1-4.

[0336] Therefore, compared with Experiment 1 which is outside the scope of the present invention, Experiments 22-24 within the scope of the present invention have superior performance in the high initial velocity region, takeoff angle, backspin, durability, impact feel, and overall score.

[0337] Furthermore, this embodiment describes the case of a hollow golf club head (driver), but the present invention can of course also be applied to hollow multi-purpose clubs and fairway woods.

[0338] Explanation of reference numerals in the attached figures

[0339] 100 golf clubs

[0340] 10A, 10B, 10C, 10D golf club heads

[0341] 12A, 12B, 12C, 12D clubhead body

[0342] 14-pole face

[0343] 1402 shaft face surface

[0344] 16. Crown

[0345] 18 Bottom

[0346] 20 Side

[0347] 22 Hollow section

[0348] 24 toes

[0349] 26 heel

[0350] 28-inch neck

[0351] 30 First face member

[0352] 3002 protrusion

[0353] 32 Second face member

[0354] 34-bar face plate

[0355] 3402 Protrusion

[0356] 36. First Floor

[0357] 38. Second Floor

[0358] 40. 3rd floor

[0359] 4002 Thin-walled section

[0360] 4004 concave part

[0361] 42 Elastic adhesive

[0362] 44A and 44B epoxy adhesives

[0363] 46 Double-sided tape

[0364] 48. Cyclic and plate-like synthetic resins

[0365] 49. Painting

[0366] 50A, 50B, 50C Carbamate Tablets

[0367] 52 First member of the first pole face

[0368] 5202 Protrusion

[0369] 54. Second face member

[0370] 56 Third member

[0371] 5602 protrusion

[0372] 58 Opening

[0373] 60 Club face outer peripheral part

[0374] 62 Peripheral plate part

[0375] 64. Protruding plate section

[0376] 66 Inner peripheral plate

[0377] 68 Weld Bead Reception Space

[0378] B weld

[0379] 70 gap

[0380] 71 Painting

[0381] 72 First member of the first pole face

[0382] 7202 First face main body

[0383] 7204 First flange

[0384] 74. Second face member

[0385] 7402 Main body of the second pole face

[0386] 7404 Second flange

[0387] 76 Third member

[0388] 7602 Third face main body

[0389] 7604 Third flange

[0390] 78 Opening

[0391] 80 Weld Bead Reception Space

[0392] 82 Synthetic Resins

[0393] 83 Painting

Claims

1. A golf club head, wherein at least a portion of the clubface is a hollow structure comprising a first layer constituting the clubface surface, a second layer located on the side of the first layer opposite to the clubface surface, and a third layer located on the side of the second layer opposite to the first layer, characterized in that, When the tensile strengths of the first layer, the second layer, and the third layer are set as S1, S2, and S3 respectively, S3≥S1>S2.

2. The golf club head according to claim 1, characterized in that, The hardness of the first layer is above D75 on a hardness tester and below HV520 on a Vickers hardness tester. The hardness of the second layer is greater than or equal to A10 and less than D60 on a hardness tester. The hardness of the third layer is above D85 on a hardness tester and below HV520 on a Vickers hardness tester.

3. The golf club head according to claim 1, characterized in that, The tensile modulus of the first layer is above 8 GPa and below 240 GPa. The tensile modulus of the second layer is above 0.5 MPa and below 3000 MPa. The tensile modulus of the third layer is above 10 GPa and below 240 GPa.

4. The golf club head according to claim 1, characterized in that, The wall thickness of the first layer is 0.1 mm or more and 1.5 mm or less. The wall thickness of the second layer is 0.1 mm or more and 1.0 mm or less. The wall thickness of the third layer is more than 2.0 mm and less than 5.0 mm.

5. The golf club head according to claim 1, characterized in that, The first layer is composed of any one of the following: metallic material, synthetic resin material, and fiber-reinforced resin material. The second layer is composed of any one of double-sided adhesive tape, synthetic resin material, or elastic material. The third layer is composed of any one of the following: metallic material, synthetic resin material, and fiber-reinforced resin material.

6. The golf club head according to claim 1, characterized in that, The third layer has a thin-walled portion that is thinner than the other parts. The thin-walled portion is formed by an open recess on the front surface of the third layer opposite to the first layer, extending towards the first layer. The second layer is configured by filling the recess.

7. The golf club head according to claim 6, characterized in that, The front surface of the third layer, excluding the recess, overlaps with the first layer.

8. The golf club head according to claim 1, characterized in that, The golf club head has a hollow clubhead body, which includes an outer periphery of the clubface with an opening thereon, a crown, a bottom, and a side portion connected to the outer periphery of the clubface. The plate-shaped third rod face member constituting the third layer is disposed on the inner side of the outer periphery of the rod face and on the inner side of the rod head body. The plate-shaped second rod face member constituting the second layer is installed overlapping the third rod face member on the inner side of the outer periphery of the rod face. The plate-shaped first rod face member constituting the first layer is installed overlapping the second rod face member on the inner side of the outer periphery of the rod face. The outer peripheral surface of the third rod face component is abutted against the inner peripheral surface of the frame-shaped inner peripheral plate of the outer peripheral portion of the rod face and installed by welding. The weld beads produced during the welding process are contained in a weld bead containing space that spans the outer periphery of the third face member and the inner periphery of the mounting plate on one side away from the interior of the club head body. The weld bead receiving space is covered by the second bar face member and the first bar face member.

9. The golf club head according to claim 1, characterized in that, The golf club head has a hollow clubhead body, which has openings formed by cutting off the face, the portion of the crown near the face, the portion of the bottom near the face, and the portion of the side near the face. The third face member constituting the third layer includes a third face body corresponding to the face portion and a third flange protruding from the outer periphery of the third face body toward the head body. The second face member constituting the second layer includes a second face body that overlaps with the third face body and a second flange that protrudes from the outer periphery of the second face body toward the head body and overlaps with the third flange, the portion of the crown near the opening, the portion of the bottom near the opening, and the portion of the side near the face. The first face member constituting the first layer includes a first face body that overlaps with the second face body and is mounted on, and a first flange that protrudes from the outer periphery of the first face body toward the clubhead body and overlaps with the second flange. The top end face of the third flange is abutted and installed by welding with the top end face of the crown portion forming the opening, the top end face of the bottom portion, and the top end face of the side portion. The weld bead produced during the welding process is contained in a weld bead containing space that spans the outer periphery of the third flange, the outer periphery of the crown, the outer periphery of the bottom, and the outer periphery of the side portion on one side away from the interior of the rod head body. The weld bead receiving space is covered by the second bar face member and the first bar face member.

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