Golf club head

Abstract

To provide a golf club head that is reduced in an amount of decrease of a coefficient of restitution, and is advantageous in enlargement of a high initial velocity area.SOLUTION: A golf club head is provided with: a contact part 34 coming in contact with a face back side 14B; and a contact member 32 having at least 2-leg parts 36, 38 extended from the contact part 34 in a direction to leave to each other. The upper leg part 36 and the lower leg 38 always bring the contact part 34 into contact with the face back side 14B by force of magnitude for substantially preventing deformation of a face part 14 when hitting a ball, and support the contact part 34 so as to be displaced to the face back side 14B when the face part 14 is deformed while the contact part 34 always comes in contact with the face back side 14B.SELECTED DRAWING: Figure 13

Description

Technical Field

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

Background Art

[0002] There has been proposed a golf club head provided with an elastic plate including a support portion attached to the sole portion and an acting portion standing up from an end of the support portion and contacting the back surface of the face (see Patent Document 1). In this golf club head, an attempt is made to improve the flight distance by utilizing the elasticity of the elastic plate that deforms following the deflection of the face portion during a hit.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above prior art, when the face portion deforms so as to deflect in the face-back direction during a hit, the deformation (deflection) of the face portion is inhibited by the elasticity of the elastic plate contacting the back surface of the face. When the amount of deformation (deflection amount) of the face portion thus decreases, the coefficient of restitution decreases, so the flight distance also decreases, and therefore, there is a concern that the high initial velocity area also becomes narrow. The present invention has been made in view of such circumstances, and an object thereof is to provide a golf club head that is advantageous in reducing the decrease amount of the coefficient of restitution and expanding the high initial velocity area.

Means for Solving the Problems

[0005] In order to achieve the above object, one embodiment of the present invention provides a golf club head including a head body having a face portion, a crown portion, a sole portion, and a side portion, wherein the interior surrounded by the face portion, the crown portion, the sole portion, and the side portion is a hollow portion. The golf club head is provided with a contact member having a contact portion that contacts the face back surface of the face portion and at least two leg portions that extend in directions away from each other from the contact portion. The tip of each leg portion is attached to any one or different locations of the face portion, the crown portion, the sole portion, and the side portion. The leg portions constantly contact the contact portion with the face back surface with a force of such a magnitude as to substantially inhibit deformation of the face portion during a golf shot, and support the contact portion so that the contact portion can be displaced relative to the face back surface while constantly contacting the face back surface when the face portion deforms. Further, one embodiment of the present invention is characterized in that the thickness of the contact portion is formed to be larger than the thickness of the leg portions. Further, one embodiment of the present invention is characterized in that the contact portion includes a main body that contacts the face back surface and a support body that supports the main body and is connected to the leg portions, and the main body and the support body are formed of different materials. Further, one embodiment of the present invention is characterized in that the amount of displacement of the contact portion in the toe-heel direction during a golf shot is larger than the amount of displacement of the contact portion along the crown-sole direction during a golf shot. Further, in one embodiment of the present invention, in a reference state where the golf club head is installed at a predetermined lie angle and loft angle with respect to the horizontal plane, a cross-section obtained by breaking the head body with a plane that includes a normal line passing through the center point of the face surface and is orthogonal to the horizontal plane is defined as a face center reference cross-section. A first plane is a plane parallel to the face center reference cross-section and spaced 20 mm in the toe direction from the face center reference cross-section. A second plane is a plane parallel to the face center reference cross-section and spaced 20 mm in the heel direction from the face center reference cross-section. A third plane is a plane parallel to the horizontal plane and spaced 15 mm in the crown portion direction from the center point. A fourth plane is a plane parallel to the horizontal plane and spaced 15 mm in the sole portion direction from the center point. When this is the case, the contact portion has its center point of the contact portion in contact with the back face of the face within a range defined by the first plane, the second plane, the third plane, and the fourth plane, and the area of the contact portion in contact with the back face of the face is 3 mm 2 or more and 400 mm 2 or less, and the thickness Δt2 of the portion of the contact portion in contact with the back face of the face is 1 mm or more and 7 mm or less. Further, in one embodiment of the present invention, when the thickness of the face portion corresponding to the portion of the back face of the face with which the contact portion abuts is defined as thickness Δt1, and the thickness of the portion of the contact portion in contact with the back face of the face is defined as thickness Δt2, the following formula (1) is satisfied. 0.5 ≦ Δt1 / Δt2 ≦ 2.0 (1) Further, in one embodiment of the present invention, an intermediate member made of an elastomer or synthetic resin material that is sandwiched between the contact portion and the back face of the face and is displaced integrally with the contact portion is provided, and the contact of the contact portion with the back face of the face is made via the intermediate member. The thickness of the intermediate member is 0.5 mm or more and 5.0 mm or less, and the elastic modulus of the intermediate member is 1 GPa or more and 50 GPa or less. Further, in one embodiment of the present invention, the intermediate member has a spherical shape, and the contact portion has a spherical curved surface that supports the intermediate member. In addition, in one embodiment of the present invention, the attachment of the tip of the leg portion to any one of the face portion, the crown portion, the sole portion, and the side portion is characterized in that it is performed by any one of welding, adhesion, brazing, and screwing. In addition, in one embodiment of the present invention, the contact member is characterized in that it is formed of any one of a metal material, a fiber-reinforced resin material, a synthetic resin material, and an elastomer. In addition, in one embodiment of the present invention, each leg portion extends obliquely from the contact portion with respect to the normal line of the back surface of the face. In addition, in one embodiment of the present invention, the at least two leg portions extend from locations separated from each other on the contact portion.

Advantages of the Invention

[0006] According to one embodiment of the present invention, no force is applied to the face portion to inhibit deformation of the face portion during hitting, and during hitting, the contact portion is displaced while contacting the back surface of the face. Therefore, the decrease in the coefficient of restitution is small, which is advantageous for expanding the high initial velocity area. In addition, since the contact portion is in contact with the back surface of the face, the reverberation of the hitting sound is shortened and the hitting feeling becomes soft. Furthermore, it is possible to adjust in the direction of decreasing the CT value. In addition, according to one embodiment of the present invention, since the thickness of the contact portion is formed to be larger than the thickness of the leg portion, when the face portion is deformed, the contact of the contact portion with the back surface of the face can be surely maintained, and at the same time, the displacement of the contact portion can be ensured due to the deformation of the leg portion. Therefore, the decrease in the coefficient of restitution is small, the high initial velocity area is ensured, the reverberation of the hitting sound is shortened, and the hitting feeling becomes soft. Furthermore, it is advantageous for adjusting the CT value. In addition, according to one embodiment of the present invention, while the main body is formed of a material with easy vibration attenuation, the support is composed of a highly durable metal material, so that the vibration of the face portion during hitting can be attenuated, the reverberation of the hitting sound is shortened, and the hitting feeling becomes soft. Furthermore, it is advantageous for suppressing the influence of vibration on the CT value and for efficiently adjusting the CT value. Further, according to an embodiment of the present invention, the displacement amount of the contact portion in the toe - heel direction during hitting is larger than the displacement amount along the crown - sole direction of the contact portion during hitting. Therefore, it is advantageous for widely securing a high - initial - velocity area in the toe - heel direction. In addition, when the center point of the contact portion abuts on the face back surface within the range defined by the first plane, the second plane, the third plane, and the fourth plane, the decrease amount of the coefficient of restitution is small, the reverberation of the hitting sound becomes short, and the hitting feeling becomes soft. Further, it is advantageous for efficiently adjusting the CT value of the portion of the face portion actually used. In this case, when the area of the contact surface that abuts on the face back surface is 3 mm 2 or more and 400 mm 2 or less, it is advantageous for efficiently adjusting the CT value. Also, when the thickness Δt2 of the portion of the contact portion that abuts on the face back surface is 1 mm or more and 7 mm or less, the decrease amount of the coefficient of restitution is small, the reverberation of the hitting sound becomes short, and the hitting feeling becomes soft. Further, it is advantageous for efficiently adjusting the CT value. Also, when the thickness of the face portion corresponding to the portion of the face back surface where the contact portion abuts is defined as thickness Δt1, and the thickness of the portion of the contact portion that abuts on the face back surface is defined as thickness Δt2, when the following formula (1) is satisfied, it is advantageous for efficiently adjusting the CT value. 0.5 ≦ Δt1 / Δt2 ≦ 2.0 (1) In addition, when an intermediate member made of an elastomer or a synthetic resin material that is sandwiched between the contact portion and the face back surface and displaced integrally with the contact portion is provided, the vibration of the face portion during hitting can be attenuated by the elastomer or the synthetic resin material, the decrease amount of the coefficient of restitution is small, the reverberation of the hitting sound becomes short, and the hitting feeling becomes soft. Further, it is advantageous for suppressing the influence of vibration on the CT value, and it is advantageous for efficiently adjusting the CT value. In this case, when the thickness of the intermediate member is 0.5 mm or more and 5.0 mm or less, it is advantageous for efficiently adjusting the CT value. Also, when the elastic modulus of the intermediate member is 1 GPa or more and 50 GPa or less, it is advantageous for efficiently adjusting the CT value. In addition, when the intermediate member is spherical, the contact portion can easily displace along the face surface while contacting the face back surface via the spherical intermediate member, which is more advantageous for expanding the high initial velocity area. In addition, the attachment of the tip of the leg portion to any of the face portion, crown portion, sole portion, and side portion can be performed by any one of welding, adhesion, brazing, and screwing. In addition, the contact member can be formed of any one of a metal material, a fiber-reinforced resin material, a synthetic resin material, and an elastomer. In addition, since the leg portion extends obliquely from the contact portion with respect to the normal line of the face back surface, when the face portion is deformed during a golf shot, while surely maintaining the contact of the contact portion with the face back surface, the displacement of the contact portion can be ensured by the deformation of the leg portion, which is advantageous for adjusting the CT value while securing the high initial velocity area. In addition, when at least two leg portions are extended from positions of the contact portion separated from each other, the contact portion can be supported in a stable state, which is advantageous for displacing while contacting the face back surface when the face portion is deformed, and is advantageous for adjusting the CT value while securing the high initial velocity area.

Brief Description of the Drawings

[0007]

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Mode for Carrying Out the Invention

[0008] (First Embodiment) Next, embodiments of the present invention will be described. As shown in FIGS. 1-5, in the present embodiment, the golf club head 10 is a hollow wood-type golf club head (driver), and is configured to include a head body 12 and a contact member 32. The head body 12 is mainly made of a metal material. As the metal material, for example, one or more of stainless steel, maraging steel, pure titanium, titanium alloy, or aluminum alloy are used. The head body 12 includes a face portion 14, a crown portion 16, a sole portion 18, and a side portion 20. As shown in FIG. 13, the head body 12 has a hollow structure in which the interior surrounded by the face portion 14, the crown portion 16, the sole portion 18, and the side portion 20 is a hollow portion 28. The face portion 14 has an upper and lower height and extends horizontally. The crown portion 16 extends rearward from the upper part of the face portion 14 with a thickness smaller than that of the face portion 14. For example, the thickness of the crown portion 16 is 0.4 mm - 1.2 mm, the thickness of the face portion 14 is 2.0 mm - 4.5 mm, and the thickness of the sole portion 18 is 0.6 mm - 1.5 mm. As shown in FIG. 13(A), the surface exposed outside the face portion 14 is the face surface 14A for hitting the ball, and the back surface facing the hollow portion 28 of the face portion 14 is the face back surface 14B. The surface exposed outside the crown portion 16 is the crown surface 16A, and the back surface facing the hollow portion 28 of the crown portion 16 is the crown back surface 16B. As shown in FIG. 1, a hosel 30 for connecting to the shaft S is provided on the crown portion 16 at a position closer to the heel 24 on the face surface 14A side. The golf club 100 is configured by connecting the shaft S to the hosel 30. As shown in FIG. 13(A), the sole portion 18 extends rearward from the lower part of the face portion 14. The surface exposed outside the sole portion 18 is the sole surface 18A, and the back surface facing the hollow portion 28 of the sole portion 18 is the sole back surface 18B. As shown in FIGS. 1 and 2, the side portion 20 extends between the toe 22 side edge and the heel 24 side edge of the face portion 14 through the face back 26 between the crown portion 16 and the sole portion 18. As shown in FIG. 2, the surface exposed outside the side portion 20 is the side surface 20A, and as shown in FIG. 13(A), the back surface facing the hollow portion 28 of the side portion 20 is the side back surface 20B. In the figure, reference numeral 19 indicates the leading edge.

[0009] (Center point Pc of the face surface 14A) Next, before explaining the contact member 32, a method for defining the center point Pc of the face surface 14A will be explained. The center point Pc of the face surface 14A is the geometric center of the face surface 14A, and various conventionally known methods can be adopted as the method for defining the center point Pc, including the first defining method and the second defining method exemplified below.

[0010] [A] First defining method for the center point Pc of the face surface 14A: This is a method for defining the center point Pc when the boundary between the face surface 14A and other parts of the golf club head 10 is clear, in other words, when the periphery of the face surface 14A is defined by a ridge line. In this case, the face surface 14A will be clearly defined. FIGS. 5-8 are explanatory diagrams showing the method for defining the center point Pc of the face surface 14A.

[0011] (1) First, as shown in FIG. 5, place the golf club head 10 on the horizontal plane HP such that the lie angle and the face angle become specified values. The state of the golf club head 10 at this time is taken as the reference state. Note that the set values of the lie angle and the face angle are, for example, the values described in the product catalog.

[0012] (2) Next, obtain a provisional center point c0 in the direction connecting the crown portion 16 and the sole portion 18. That is, as shown in FIG. 5, draw a perpendicular line f0 that intersects the approximate center point of a line parallel to the horizontal plane HP connecting the toe 22 and the heel 24 (hereinafter referred to as the horizontal line). Take the midpoint between the a0 point where this perpendicular line f0 intersects the upper edge of the face surface 14A and the b0 point where the perpendicular line f0 intersects the lower edge of the face surface 14A as the provisional center point c0.

[0013] (3) Next, draw a horizontal line g0 passing through the provisional center point c0 as shown in FIG. 6. (4) Next, as shown in FIG. 7, take the midpoint between the d0 point where the horizontal line g0 intersects the edge on the toe 22 side of the face surface 14A and the e0 point where the horizontal line g0 intersects the edge on the heel 24 side of the face surface 14A as the provisional center point c1.

[0014] (5) Next, draw a perpendicular line f1 passing through the provisional center point c1 as shown in FIG. 8, and take the midpoint between the a1 point where this perpendicular line f1 intersects the upper edge of the face surface 14A and the b1 point where the perpendicular line f1 intersects the lower edge of the face surface 14A as the provisional center point c2. Here, if the provisional center points c1 and c2 coincide, that point is defined as the center point Pc of the face surface 14A. If the provisional center points c1 and c2 do not coincide, repeat the steps (2) to (5). Since the face surface 14A has a curved surface, when determining the midpoint of the horizontal line g0 and the lengths of the perpendicular lines f0 and f1, the lengths of the horizontal line g0 and the perpendicular lines f0 and f1 shall be the lengths along the curved surface of the face surface 14A. The face center line CL is defined as a straight line passing through the center point Pc and extending in a direction perpendicular to the toeheel direction.

[0015] [B]Second method for defining the center point Pc of the face surface 14A: Next, the definition of the center point Pc in the case where the periphery of the face surface 14A is connected to other parts of the golf club head 10 by a curved surface and the face surface 14A cannot be clearly defined will be described.

[0016] As shown in FIG. 9, the golf club head 10 is hollow, the reference symbol G0 indicates the center of gravity of the golf club head 10, and the reference symbol Lp is a straight line connecting the center of gravity G0 and the center of gravity FG on the face surface. In other words, the straight line Lp is a perpendicular line of the face surface 14A passing through the center of gravity G0. That is, the point obtained by projecting the center of gravity G0 of the golf club head 10 onto the face surface 14A is the center of gravity FG on the face surface. Here, as shown in FIG. 10, consider a number of planes H1, H2, H3,..., Hn including the straight line Lp connecting the center of gravity G0 and the center of gravity FG on the face surface.

[0017] When the golf club head 10 is broken along each of the planes H1, H2, H3,..., Hn, measure the radius of curvature r0 of the outer surface of the golf club head 10 in the cross section as shown in FIG. 11. When measuring the radius of curvature r0, assume that there are no face lines, punch marks, etc. on the face surface 14A. The radius of curvature r0 is continuously measured outward (upward and downward directions in FIG. 11) from the center point Pc of the face surface 14A. Then, define the contour line I representing the periphery of the face surface 14A as the portion where the radius of curvature r0 first becomes less than or equal to a predetermined value in the measurement. The predetermined value is, for example, 200 mm. As shown in FIGS. 10 and 11, the area surrounded by the contour line I determined based on a plurality of planes H1, H2, H3, …, Hn is defined as the face surface 14A.

[0018] Next, as shown in FIG. 12, the golf club head 10 is placed on a horizontal ground surface (horizontal plane HP) such that the lie angle and the face angle become specified values. The straight line LT extends vertically through the toe 22 side point PT of the face surface 14A. The straight line LH extends vertically through the heel 24 side point PH of the face surface 14A. The straight line LC is parallel to the straight line LT and the straight line LH. The distance between the straight line LC and the straight line LT is equal to the distance between the straight line LC and the straight line LH. The symbol Pu indicates the upper side point of the face surface 14A, and the symbol Pd is the lower side point of the face surface 14A. Both the upper side point Pu and the lower side point Pd are the intersection points of the straight line LC and the contour line I. The center point Pc is defined as the midpoint of the line segment connecting the upper side point Pu and the lower side point Pd.

[0019] Next, the specifications of each part of the golf club head 10 will be described in detail. As shown in FIGS. 1 - 5, the golf club head 10 is set to a reference state in which it is installed at a predetermined lie angle and loft angle with respect to the horizontal plane HP. Hereinafter, the reference state of the golf club head 10 will be simply referred to as the "reference state". As shown in FIGS. 1 and 13(A), in the reference state, the cross - section obtained by breaking the head body 12 with a plane X that includes the normal line passing through the center point Pc of the face surface 14A and is orthogonal to the horizontal plane HP is defined as the face center reference cross - section Pfc. In other words, the face center reference cross - section Pfc is, in the reference state, the cross - section obtained by breaking the head body 12 with a plane X that includes the face center line CL and is orthogonal to the horizontal plane HP. Also, the cross - section obtained by breaking the head body 12 with an arbitrary plane parallel to the face center reference cross - section Pfc is defined as the face reference cross - section Pf. Therefore, the face reference cross - section Pf includes the face center reference cross - section Pfc.

[0020] (Contact member 32) Next, the contact member 32 will be described. In the following, five forms of the first contact member 32A to the fifth contact member 32E will be individually described as the contact member 32, but in some cases, these contact members may be collectively referred to as the contact member 32. As shown in FIGS. 13(A) and 14(A)-(F), the first contact member 32A is provided in the hollow portion 28 and attached to the head body 12, and has a contact portion 34 and at least two or more legs. In the present embodiment, it has two elastically deformable legs 36 and 38. In the present embodiment, the first contact member 32A is formed of a metal material such as titanium, but the contact member 32 can be formed of any of a metal material, a fiber-reinforced resin material, a synthetic resin material, and an elastomer. Note that the contact portion 34 and the legs 36 and 38 may be formed of different materials, but if they are formed of the same material as in the present embodiment, they can be easily and reliably manufactured, which is advantageous in reducing costs. The contact portion 34 is a portion that contacts the face back surface 14B. As shown in FIGS. 14(A)-(F), in the present embodiment, the contact portion 34 has a substantially rectangular plate shape with its long sides aligned in the toe-heel direction when viewed from the front, and has a substantially rectangular contact surface 3402 that contacts the face back surface 14B. The thickness of the contact portion 34 is formed to be larger than the thicknesses of the respective legs 36 and 38.

[0021] Each of the legs 36 and 38 extends in a direction away from each other from positions on the contact portion 34 that are separated from each other. Specifically, they extend in directions away from each other from a pair of long sides constituting the contact portion 34. Note that each of the legs 36 and 38 may extend in a direction away from the same position on the contact portion 34, but if they extend in directions away from positions on the contact portion 34 that are separated from each other as in the present embodiment, the contact portion 34 can be supported in a stable state, and as will be described later, when the face portion 14 is deformed, it is advantageous for displacement while contacting the face back surface 14B. The tips of the respective leg portions 36 and 38 are attached to any one or different locations of the face portion 14, the crown portion 16, the sole portion 18, and the side portion 20. In the present embodiment, as shown in FIG. 13(A), the tip of one of the two leg portions 36 is joined by welding to a location near the crown portion 16 at substantially the center in the toe-heel direction of the face portion 14, and the tip of the other leg portion 38 is joined by welding to a location near the sole portion 18 at substantially the center in the toe-heel direction of the face portion 14. Note that the method of attaching the contact member 32 to the head body 12 will be described later.

[0022] As shown in FIG. 14(D), the respective leg portions 36 and 38 extend in directions away from each other from a pair of long sides constituting the contact portion 34. In other words, the upper leg portion 36 and the lower leg portion 38 provided at the upper and lower portions of the contact portion 34 respectively are configured. The upper leg portion 36 includes an upper inclined portion 3602 that inclines in the face-back direction as it extends upward (toward the crown portion 16) from the upper portion of the contact portion 34, an upper bent portion 3604 that is bent toward the face portion 14 from the upper end of the upper inclined portion 3602, and an upper engaging portion 3606 that is bent upward from the front end of the upper bent portion 3604. The lower leg portion 38 includes a lower inclined portion 3802 that inclines in the face-back direction as it extends downward (toward the sole portion 18) from the lower portion of the contact portion 34, a lower bent portion 3804 that is bent toward the face portion 14 from the lower end of the lower inclined portion 3802, and a lower engaging portion 3806 that is bent downward from the front end of the lower bent portion 3804. Therefore, the upper leg portion 36 and the lower leg portion 38 extend obliquely with respect to the normal line of the face back surface 14B from the contact portion 34.

[0023] Here, an example of the method of attaching the first contact member 32A to the head body 12 will be described. As shown in FIGS. 15 and 16, the face portion 14 is configured to include a head body member 40 and a face member 42. The face portion 14 is formed with an opening 4002, and the head main body member 40 is the portion of the face portion 14 excluding the opening 4002. The face member 42 is a member that closes the opening 4002. Therefore, the face surface 14A of the face portion 14 is composed of a portion formed by the face member 42 and a portion formed by the periphery of the opening 4002 of the head main body member 40. Prepare such a head main body member 40 and face member 42. As shown in FIG. 15, the first contact member 32A faces the contact surface 3402 forward in the opening 4002 and engages the upper engaging portion 3606 and the lower engaging portion 3806 with the upper edge of the head main body member 40 above the opening 4002 and the lower edge of the head main body member 40 below the opening 4002. In this state, the upper engaging portion 3606 and the lower engaging portion 3806 are spot-welded to the respective edges of the head main body member 40, so that the first contact member 32A is assembled to the head main body member 40. Next, the opening 4002 is closed with the face member 42. As shown in FIG. 16, upper concave portions 4202 and lower concave portions 4204 that engage with the upper engaging portion 3606 and the lower engaging portion 3806 are formed at the upper and lower edges of the face member 42 corresponding to the upper engaging portion 3606 and the lower engaging portion 3806, respectively, in order to be smoothly positioned and engaged with the upper engaging portion 3606 and the lower engaging portion 3806. As shown in FIG. 17, with the first contact member 32A assembled to the head main body member 40, the opening 4002 is closed by the face member 42, and the upper engaging portion 3606 and the lower engaging portion 3806 and the upper concave portion 4202 and the lower concave portion 4204 are respectively fitted together. At this time, the portion of the face surface 14A on the face member 42 side is lifted about 1 mm with respect to the portion of the face surface 14A around the opening 4002 of the head main body member 40, and a force is applied from the portion of the face surface 14A of the face member 42 to make the portion of the face surface 14A of the face member 42 and the portion of the face surface 14A of the head main body member 40 flush, and about 10 spot welds are performed. As a result, the contact portion 34 is in a state where stress is generated when it hits the face back surface 14B. In other words, the contact portion 34 is in a state where tension is applied and it is in contact with the face back surface 14B. And the stress (tension) at this time is a force of such a magnitude that it hardly inhibits the deformation of the face portion 14 during a ball hit. Then, the edge of the face member 42 and the edge of the opening 4002 are welded (plasma or laser welding) over the entire circumference, and the face member 42 is integrally joined to the head body member 40, whereby the face portion 14 is formed. Next, by removing the bead generated on the face surface 14A by welding through polishing, a smooth face surface 14A without unevenness is formed, and the head body 12 is completed.

[0024] As a result, as shown in FIG. 13(A), the tips of the upper leg portion 36 and the lower leg portion 38 of the first contact member 32A (the upper engaging portion 3606 and the lower engaging portion 3806) are attached to the face portion 14, and the contact portion 34 (contact surface 3402) is in contact with the face back surface 14B, and the contact portion 34 is supported by the upper leg portion 36 and the lower leg portion 38. That is, the upper leg portion 36 and the lower leg portion 38 constantly bring the contact portion 34 (contact surface 3402) into contact with the face back surface 14B with a force of such a magnitude that it hardly inhibits the deformation of the face portion 14 during a ball hit, and support the contact portion 34 so that when the face portion 14 deforms, the contact portion 34 (contact surface 3402) can be displaced with respect to the face back surface 14B while constantly contacting the face back surface 14B. In other words, the contact portion 34 is supported by the leg portions 36 and 38 so as to move while being in contact along the face back surface 14B. When the face portion 14 is deformed by a ball hit, at least a part of the contact portion 34 moves along the face back surface 14B while being in contact with the face back surface 14B. When the face portion 14 returns to its original shape, the contact portion 34 also moves along the face back surface 14B while being in contact and returns to its original position. In addition, in this specification, the upper part 36 and the lower part 38 are configured such that the contact part 34 always contacts the face back surface 14B with a force that hardly inhibits the deformation of the face part 14 during hitting. The force that hardly inhibits the deformation of the face part 14 during hitting means a force of such a magnitude that the face part 14 can deform almost without being affected by the contact part 34, in the same manner as when the contact part 34 that contacts the face back surface 14B during hitting is not provided. Specifically, for the face part 14 to deform during hitting, it is necessary to move the contact part 34 biased by the upper part 36 and the lower part 38. The force that hardly inhibits the deformation of the face part 14 during hitting means that, compared to the force that deforms the face part 14 during hitting, the force that causes the contact part 34 biased by the upper part 36 and the lower part 38 to move following the deformation of the face part 14 is small, and it is a force of such a magnitude that the face part 14 can deform almost in the same manner as when the contact part 34 is not provided during hitting. In addition, in this specification, "always contact" means a state in which at least a part of the contact part 34 is substantially always in contact with the face back surface 14B, including cases where the contact part 34 is instantaneously (about 1 - 2 / 10000 seconds) separated from the face back surface 14B. In addition, during hitting, the Toe heel direction displacement amount along the [contact part 34] (the relative displacement amount of the contact part 34 with respect to the face back surface 14B) of the contact part 34 during hitting is Crown sole direction larger than the displacement amount of the [contact part 34] during hitting, which is advantageous for widely securing the high initial velocity area in the toe - heel direction as compared to the case where it is not. Generally, the dispersion of hitting points in the toe - heel direction is larger than the dispersion of hitting points in the crown - sole direction. Therefore, when the high initial velocity area is widely secured in the toe - heel direction in this way, the dispersion of hitting points can be covered by the high initial velocity area, which is advantageous for ensuring the flying distance even for a beginner user.

[0025] Here, with reference to FIG. 18, the high initial velocity area of the golf club head according to the embodiment will be described. The high initial velocity area (sweet area) refers to an area where, even when a golf ball is struck at a point outside the sweet spot on the face surface 14A, a flight distance approximately equivalent to that when struck at the sweet spot (for example, about 98% of the maximum initial velocity of the ball) can be obtained. Therefore, for a user with a large variation in hitting points, such as a beginner, expanding the high initial velocity area is advantageous in ensuring an average flight distance. FIG. 18 is a diagram schematically showing the relationship between the position of the golf club head 10 in the toe - heel direction and the initial velocity Vb of the ball when hitting the ball at that position. Curve V0 shows the initial velocity of the ball when hitting the ball with a general golf club head having no member in contact or abutting on the back surface 14B of the face. Curve V1 shows the initial velocity of the ball when hitting the ball with a golf club head as a comparative example in which an elastic plate abuts on the back surface 14B of the face described in the prior art. Curve V2 shows the initial velocity of the ball when hitting the ball with the golf club head 10 having the first contact member 32A of the embodiment. In the figure, COR0.81 indicates the coefficient of restitution. Here, the range in which an initial velocity of COR0.81 or more is obtained is defined as the high initial velocity area. As is clear from FIG. 18, the high initial velocity area A2 of curve V2 is most widely ensured with respect to the high initial velocity area A0 of curve V0 and the high initial velocity area A1 of curve V1, which is advantageous in expanding the high initial velocity area. That is, curve V2 minimizes the decrease in the initial velocity and has a wide peak width, while curve V1 almost coincides with a curve obtained by parallel - shifting the entire curve V0 in the direction in which the ball initial velocity Vb decreases. Moreover, the decrease in the initial velocity of curve V1 is large, and the peak width is narrower compared to curve V2. That is, the inventors have obtained the finding that the high initial velocity area A2 can be expanded by the contact portion 34 contacting the back surface 14B of the face and being displaced along the face surface 14A when the face portion 14 deforms during hitting the ball. On the other hand, in the comparative example, when deformation of the face portion 14 occurs during hitting, since the elastic plate suppresses the deflection of the face portion, the high initial velocity area A1 is reduced.

[0026] As described above, according to the present embodiment, a contact member 32 is provided which has a contact portion 34 that contacts the face back surface 14B and at least two leg portions 36, 38 that extend in directions away from each other from the contact portion 34. The upper leg portion 36 and the lower leg portion 38 constantly contact the contact portion 34 with the face back surface 14B with a force of a magnitude that hardly inhibits the deformation of the face portion 14 during hitting, and supports the contact portion 34 so that the contact portion 34 can be displaced with respect to the face back surface 14B while constantly contacting the face back surface 14B when the face portion 14 deforms. Therefore, in the present embodiment, unlike the prior art, a force that suppresses the deformation of the face portion 14 during hitting, that is, a large force that inhibits the deformation of the face portion 14 during hitting, is not applied to the face portion 14. During hitting, the contact portion 34 displaces while contacting the face back surface 14B. Thus, the decrease in the coefficient of restitution is small, which is advantageous for expanding the high initial velocity area. Also, since the contact portion 34 constantly contacts the face back surface 14B, the reverberation of the hitting sound is shortened and the hitting feeling becomes soft. Furthermore, it becomes possible to adjust in the direction of decreasing the CT value.

[0027] Also, in the present embodiment, since the thickness of the contact portion 34 is formed to be larger than the thicknesses of the leg portions 36, 38, when the face portion 14 deforms during hitting, while reliably maintaining the contact of the contact portion 34 with the face back surface 14B, displacement of the contact portion 34 can be ensured due to the deformation of the leg portions 36, 38. Therefore, the decrease in the coefficient of restitution is small, the high initial velocity area is ensured, the reverberation of the hitting sound is shortened, and the hitting feeling becomes soft. Furthermore, it is advantageous for adjusting the CT value.

[0028] In addition, in the present embodiment, since the leg portions 36 and 38 extend obliquely from the contact portion 34 with respect to the normal line of the face back surface 14B, when the face portion 14 deforms during a hit, while reliably maintaining the contact of the contact portion 34 with the face back surface 14B, displacement of the contact portion 34 can be ensured due to the deformation of the leg portions 36 and 38. Therefore, the amount of decrease in the coefficient of restitution is small, the reverberation of the hitting sound is shortened while securing a high initial velocity area, and the hitting feeling becomes soft. Furthermore, it is advantageous for adjusting the CT value.

[0029] FIG. 13(B) is a first modification example, showing a golf club head 10 provided with a second contact member 32B. In the following description of the modification examples, the same parts and members as those in the embodiment are denoted by the same reference numerals to simplify the description, and the different parts will be mainly described. The contact portion 34 of the second contact member 32B includes a main body 44 that contacts the face back surface 14B, and a support 46 that supports the main body 44 and is connected to the leg portions 36 and 38. The main body 44 and the support 46 are formed of different materials. In this case, the contact surface 3402 that contacts the face back surface 14B is constituted by the surface of the main body 44. By doing so, for example, when the main body 44 is formed of a material (elastomer or synthetic resin material) that easily attenuates vibration, and the support 46 is constituted by a highly durable metal material, vibration of the face portion 14 during a hit can be attenuated, the amount of decrease in the coefficient of restitution is small, the reverberation of the hitting sound is shortened while securing a high initial velocity area, and the hitting feeling becomes soft. Furthermore, it is advantageous for suppressing the influence of vibration on the CT value, and is advantageous for efficiently adjusting the CT value. In this case, when the thickness of the main body 44 is 0.5 mm or more and 5.0 mm or less, it is advantageous for efficiently adjusting the CT value, similar to the cases of the intermediate members 52A and 52B described later. Also, when the elastic modulus of the main body 44 is 1 GPa or more and 50 GPa or less, it is advantageous for efficiently adjusting the CT value.

[0030] FIG. 19 shows a golf club head 10 using a third contact member 32C, which is a second modification. The contact portion 34 of the third contact member 32C has a circular disk shape when viewed from the front, and the surface located in front of the contact portion 34 is a contact surface 3402 that contacts the face back surface 14B. Two upper legs 34 extend upward from the upper part of the contact portion 34, and their tips are joined to the upper part of the edge of the opening 4002 by welding. One lower leg 38 extends downward from the lower part of the contact portion 34, and its tip is joined to the lower part of the edge of the opening 4002 by welding. The thickness of the contact portion 34 is formed to be larger than the thicknesses of the legs 36 and 38, and the legs 36 and 38 extend obliquely with respect to the normal line of the face back surface 14B from the contact portion 34. Even in such a modification, the same effects as those of the above-described embodiment are achieved.

[0031] (Each parameter) Next, the range of the portion where the contact portion 34 contacts the face back surface 14B, the area S where the contact portion 34 contacts the face back surface 14B, the thicknesses Δtp of the intermediate members 52A and 52B described later, the elastic modulus E, the thickness Δt2 of the portion of the contact portion 34 that is in contact with the face back surface 14B, and the regulations regarding the thickness Δt1 of the face portion 14 and the thickness Δt2 of the contact portion 34 will be described.

[0032] (Range of the face back surface 14B where the contact portion 34 contacts) As shown in FIG. 1, a first plane P1 is defined as a plane parallel to the face center reference section Pfc and spaced 20 mm in the toe direction from the face center reference section Pfc. A second plane P2 is defined as a plane parallel to the face center reference section Pfc and spaced 20 mm in the heel direction from the face center reference section Pfc. A third plane P3 is defined as a plane parallel to the horizontal plane HP and spaced 15 mm in the crown portion 16 direction from the center point Pc. A fourth plane P4 is defined as a plane parallel to the horizontal plane HP and spaced 15 mm in the sole portion 18 direction from the center point Pc. In this case, if the center point 34P of the contact portion 34 (contact surface 3402) (the geometric center point of the contact portion 34 (contact surface 3402)) contacts the face back surface 14B within the range defined by the first plane P1, the second plane P2, the third plane P3, and the fourth plane P4, the reduction amount of the coefficient of restitution of the portion of the face portion 14 actually used is small, a high initial velocity area is ensured, the reverberation of the hitting sound becomes short, and the hitting feeling becomes soft. Furthermore, it is advantageous in suppressing the influence of vibration on the CT value and in efficiently adjusting the CT value. This is because the above range substantially includes the distribution range of hitting points on the face surface 14A when an ordinary golfer hits a ball. Also, when the contact portion 34 contacts the face back surface 14B outside the above range, the effect of reducing the reduction amount of the coefficient of restitution of the portion of the face portion 14 actually used, ensuring a high initial velocity area, shortening the reverberation of the hitting sound, and softening the hitting feeling is reduced. Furthermore, the effect of suppressing the influence of vibration on the CT value and efficiently adjusting the CT value is reduced.

[0033] (Area S) The area S where the contact portion 34 contacts the face back surface 14B is 3 mm 2 or more and 400 mm 2 or less, which is advantageous for efficiently adjusting the CT value while ensuring a high initial velocity area. When the area S where the contact portion 34 contacts the face back surface 14B is below the above range, the effect of ensuring a high initial velocity area is reduced, the effect of applying a load from the contact portion 34 to the face back surface 14B is reduced, and the effect of efficiently adjusting the CT value is reduced. Also, the effect of reducing the reduction amount of the coefficient of restitution, ensuring a high initial velocity area, shortening the reverberation of the hitting sound, and softening the hitting feeling is also reduced. When the area S where the contact portion 34 contacts the face back surface 14B exceeds the above range, while a high initial velocity area can be ensured, the load applied from the contact portion 34 to the face back surface 14B becomes excessive, and the effect of efficiently adjusting the CT value is reduced. Also, the effect of reducing the reduction amount of the coefficient of restitution, ensuring a high initial velocity area, shortening the reverberation of the hitting sound, and softening the hitting feeling is also reduced.

[0034] (Thickness Δt2) In addition, the thickness Δt2 of the portion of the contact portion 34 in contact with the face back surface 14B is advantageously 1 mm or more and 7 mm or less in terms of efficiently adjusting the CT value while securing the initial velocity area. In addition, there is an effect that the reverberation of the hitting sound becomes shorter while ensuring a high initial velocity area with a small decrease in the coefficient of restitution, and the hitting feeling becomes softer. When the thickness Δt2 is below the above range, the effect of securing the initial velocity area decreases, and the effect of efficiently adjusting the CT value decreases. In addition, there is an effect that the reverberation of the hitting sound becomes shorter while ensuring a high initial velocity area with a small decrease in the coefficient of restitution, and the hitting feeling becomes softer, but this effect decreases. When the thickness Δt2 exceeds the above range, while the initial velocity area can be secured, the effect of efficiently adjusting the CT value decreases. In addition, there is an effect that the reverberation of the hitting sound becomes shorter while ensuring a high initial velocity area with a small decrease in the coefficient of restitution, and the hitting feeling becomes softer, but this effect decreases. Note that when the intermediate members 52A and 52B described later are disposed between the face back surface 14B and the contact portion 34, the above area S is the area where the contact portion 34 contacts the face back surface 14B via the intermediate members 52A and 52B, and the above thickness Δt2 is the thickness of the portion of the contact portion 34 in contact with the face back surface 14B via the intermediate member.

[0035] (Intermediate member) FIG. 20 shows a third modification, which is a golf club head provided with a fourth contact member 32D and an intermediate member 52A. As shown in FIG. 20, the golf club head 10 has a cup face structure, and an engaging portion 4802 that constitutes a part of the crown portion 16 or a part of the sole portion 18 is provided to extend in the face back direction from the edge portion of the face portion 14. Further, a face member (cup face) 48 having such an engaging portion 4802 is welded to the opening 5002 of the head body member 50. The fourth contact member 32D includes a rectangular plate-shaped contact portion 34, a pair of upper leg portions 36A and 36B that extend upward from both ends of the upper long side of the pair of long sides constituting the contact portion 34, and the tips thereof are welded to the upper edge of the opening 5002, and a pair of lower leg portions 38A and 38B that extend downward from both ends of the lower long side of the pair of long sides constituting the contact portion 34, and the tips thereof are welded to the lower edge of the opening 5002. The contact portion 34 includes a rectangular contact surface 3402 facing the face back surface 14B, and a rectangular frame portion 3410 protruding forward along the four sides of the contact surface 3402.

[0036] The intermediate member 52A is formed of an elastomer or a synthetic resin material. The intermediate member 52A has a rectangular contour that is slightly smaller than the contact portion 34 in plan view, and exhibits a rectangular parallelepiped shape supported by the contact surface 3402 and the inner surface of the frame portion 3410, and the surface opposite to the contact surface 3402 is an intermediate member side contact surface 5202 that contacts the face back surface 14B. Also, the intermediate member 52A is formed with a uniform wall thickness Δtp. In a state where the opening 5002 is closed by the face member 48, the intermediate member 52A is sandwiched between the contact portion 34 and the face back surface 14B and is displaced integrally with the contact portion 34. That is, the contact of the contact portion 34 with the face back surface 14B is made via the intermediate member 52A. Also, similar to the above-described embodiment, the wall thickness of the contact portion 34 is formed to be larger than the wall thicknesses of the leg portions 36A, 36B, 38A, and 38B, and the leg portions 36A, 36B, 38A, and 38B extend obliquely with respect to the normal line of the face back surface 14B from the contact portion 34.

[0037] Even in such a modification, the same effects as those of the above-described embodiment are achieved. In addition, if an intermediate member 52A is provided between the contact portion 34 and the back surface 14B of the face and is displaced integrally with the contact portion 34, the vibration of the face portion 14 during hitting can be attenuated by an elastomer or a synthetic resin material, which is advantageous for suppressing the influence of the vibration on the CT value and for efficiently adjusting the CT value. Also, it is advantageous for obtaining an effect of shortening the reverberation of the hitting sound while securing a high initial velocity area with a small decrease in the coefficient of restitution and making the hitting feeling soft. Furthermore, since the intermediate member 52A is interposed between the contact portion 34 and the back surface 18B of the sole, it is possible to suppress the contact portion 34 and the back surface 14B of the face from directly contacting and wearing, which is advantageous for improving the durability of the golf club head 10. In this case, when the thickness Δtp of the intermediate member 52A is set to 0.5 mm or more and 5.0 mm or less, it is advantageous for efficiently adjusting the CT value. Also, it is advantageous for obtaining an effect of shortening the reverberation of the hitting sound while securing a high initial velocity area with a small decrease in the coefficient of restitution and making the hitting feeling soft. When the thickness Δtp of the intermediate member 52A is less than the above range, it becomes difficult to suppress the vibration of the face portion 14 during hitting, so the effect of efficiently adjusting the CT value decreases. Also, the effect of shortening the reverberation of the hitting sound while securing a high initial velocity area with a small decrease in the coefficient of restitution and making the hitting feeling soft decreases. When the thickness Δtp of the intermediate member 52A exceeds the above range, the vibration of the face portion 14 during hitting is suppressed too much, so the effect of efficiently adjusting the CT value decreases. Also, the effect of shortening the reverberation of the hitting sound while securing a high initial velocity area with a small decrease in the coefficient of restitution and making the hitting feeling soft decreases. Also, when the elastic modulus E of the intermediate member 52A is set to 1 GPa or more and 50 GPa or less, it is advantageous for efficiently adjusting the CT value. Also, it is advantageous for obtaining an effect of shortening the reverberation of the hitting sound while securing a high initial velocity area with a small decrease in the coefficient of restitution and making the hitting feeling soft. If the elastic modulus E of the intermediate member 52A is less than the above range, it becomes difficult to suppress the vibration of the face portion 14 during hitting, so the effect of efficiently adjusting the CT value is reduced. Also, while the decrease amount of the coefficient of restitution is small and the high initial velocity area is secured, the reverberation of the hitting sound becomes short, and the effect that the hitting feeling becomes soft is reduced. If the elastic modulus E of the intermediate member 52A exceeds the above range, the vibration of the face portion 14 during hitting is suppressed too much, so the effect of efficiently adjusting the CT value is reduced. Also, while the decrease amount of the coefficient of restitution is small and the high initial velocity area is secured, the reverberation of the hitting sound becomes short, and the effect that the hitting feeling becomes soft is reduced.

[0038] FIG. 21 is a modified example (the fourth modified example) of FIG. 20, and shows a golf club head 10 provided with a fifth contact member 32E and in which the intermediate member 52B has a spherical shape and is formed of an elastomer or a synthetic resin material. The fifth contact member 32E includes a contact portion 34, and an upper leg portion 36 and a lower leg portion 38 that extend vertically from the upper and lower portions of the contact portion 34. The thickness of the contact portion 34 is formed to be larger than the thicknesses of the leg portions 36 and 38, and the leg portions 36 and 38 extend obliquely with respect to the normal line of the face back surface 14B from the contact portion 34. The contact portion 34 has a spherical curved surface 3420 that supports the intermediate member 52B. The tips of the upper leg portion 36 and the lower leg portion 36 are sandwiched between the edge of the opening 5002 of the head body member 50 and the edge of the face member 48 and welded to be attached to the head body 44. Therefore, the intermediate member 52B is sandwiched between the contact portion 34 and the face back surface 14B and is displaced integrally with the contact portion 34, and the contact of the contact portion 34 with the face back surface 14B is made via the intermediate member 52B. Here, the thickness of the intermediate member 52B, in other words, the diameter of the intermediate member 52B is 0.5 mm or more and 5.0 mm or less, and the elastic modulus of the intermediate member 52B is 1 GPa or more and 50 GPa or less. Even in such a modified example of FIG. 21, the same effects as those of the modified example of FIG. 20 are achieved. In addition, in the modification example of FIG. 21, since the intermediate member 52B has a spherical shape, when deformation of the face portion 14 occurs during a hit, the contact portion 34 easily displaces along the face surface 14A while contacting the face back surface 14B via the spherical intermediate member 52B, which is more advantageous for expanding the high initial velocity area. Also, it is advantageous for obtaining an effect of shortening the reverberation of the hitting sound while securing a high initial velocity area with a small decrease in the coefficient of restitution and making the hitting feeling soft.

[0039] In addition, in each of the above-described embodiments, the case where the tips of the legs 36 and 38 are attached to the head body 44 by welding has been described. However, the attachment of the tips of the legs 36 and 38 to any of the face portion 14, the crown portion 16, the sole portion 18, and the side portion 20 may be performed by various conventionally known methods such as welding, adhesion, brazing, and screwing.

[0040] Hereinafter, experimental examples of the present invention will be described. FIGS. 22 to 26 are diagrams showing experimental results of the golf club head 10 according to the present invention. Golf club heads 10 as samples were created for each experimental example, and the following four evaluation items were measured to obtain an index (evaluation score), and the total score of the four indexes was obtained.

[0041] (1) CT value The CT value of the golf club head 10 was measured by a pendulum test defined by the USGA, and the difference Δt = t1 - t2 between the CT value t1 in the first state where the CT value is not adjusted by the contact member 32 and the CT value t2 in the second state where the CT value is adjusted by the contact member 32 was measured, and was evaluated by an index with the difference Δt of Experimental Example 1 corresponding to the comparative example being 100. The larger the index of the CT value, the more the CT value can be decreased, in other words, the more the CT value can be adjusted, and therefore, the CT value can be adjusted efficiently, indicating that the evaluation of the CT value is good. In addition, the measurement positions of the CT values on the face surface 14A were measured at a pitch of 5 mm vertically, horizontally, and diagonally with respect to the centroid where the contact portion 34 and the face back surface 14B were in contact (a total of 9 points), with the centroid as the reference point. The CT values were measured 5 times at each measurement position, and the average value of the total 45 CT values was calculated for the first state and the second state (t1, t2) respectively, and the exponent of the difference Δt = t1 - t2 was obtained.

[0042] (2) High initial velocity area (sweet area) With the center point Pc of the face surface 14A as the center, 45 points Pi were set at equal intervals in the toeheel direction and the crownsole direction. Using a dedicated swing robot, the golf club was swung at the 45 points Pi, and the initial velocity of the golf ball was measured by a measuring instrument. The head speed was set at 40 m / s. The initial velocity data of the 45 points were interpolated, and the area of the high initial velocity area of the face surface 14A where the initial velocity of the golf ball was 98% or more of the maximum initial velocity was indexed. The data at the upper points (crown portion 16 side) and the lower points (sole portion 18 side) from the center point Pc were weighted more heavily according to the actual hitting positions of the golfer. The data of the high initial velocity area were shown as an index with the measurement result of the golf club head 10 in Experimental Example 1 being 100. The larger the index, the better the evaluation of the high initial velocity area.

[0043] (3) Durability A golf ball was repeatedly hit against the face surface 14A of the golf club head 10 fixed to the shaft with an air cannon, and the number of hits required until deformation, cracking of the face portion 14, or damage to the contact member 32 occurred was measured, and the number of hits was indexed. The ball speed was set at 50 m / s. The hitting position was the center point Pc of the face surface 14A. In this case, the measurement result of the golf club head 10 in Experimental Example 1 corresponding to the comparative example was shown as an index of 100. The larger the index, the better the evaluation of durability.

[0044] (4) Feel at impact The hitting feeling is dominated by the hitting sound when the ball is struck with the golf club head 10. Generally, when the reverberation of the hitting sound is short, the hitting feeling is soft and favorable, and the evaluation by golfers is high. The method for evaluating the hitting feeling is as follows. Using a dedicated swing robot, the golf club is swung at a head speed of 40 m / s with the center point Pc as the hitting point, the hitting sound of the golf ball is measured by a noise meter, and the vibration waveform data of the hitting sound is sampled and recorded at a predetermined sampling period. Next, the reverberation parameter T is calculated. The reverberation parameter T is a parameter representing the degree of attenuation of the hitting sound. In calculating the reverberation parameter T, first, the recorded vibration waveform data is based on the first sample data (starting point data) on the time axis as the reference number, and a block group α in which the sound pressure vibration waveform is sequentially divided at a predetermined number of samples, for example, 100 samples, is created from this number. Then, the sum of the squares of the levels of the vibration waveforms is obtained for each block Ak of the block group α, and the logarithmic value of this sum of squares (hereinafter referred to as the block value) is obtained for each block. Then, from each block of the block group α, the maximum sound pressure block with the maximum block value is extracted as the starting point block. And a value 30 dB lower than the block value of this maximum sound pressure block is set as the end point block value, and in a plurality of blocks after the starting point block, the end point block where the block value first becomes equal to or lower than the end point block value is extracted. And the time width between the earliest sample data on the time axis of these starting point block and end point block is taken as the reverberation parameter T. Therefore, the reverberation parameter T corresponds to the reverberation time of the hitting sound. The shorter the reverberation parameter T, the shorter the reverberation, the softer the hitting feeling, and the higher the evaluation of the hitting feeling. In this case, the hitting feeling data is indicated by an exponent with the reciprocal 1 / T of the reverberation parameter T of the golf club head 10 in Experimental Example 1 corresponding to the comparative example being 100. The larger the exponent, the better the evaluation of the hitting feeling. Incidentally, as the method for calculating the reverberation parameter T, for example, the method described in Japanese Patent No. 4840106 can be used. However, the method for evaluating the reverberation time of the hitting sound is not limited, and the reverberation time of the hitting sound can be obtained by various conventionally known methods to evaluate the hitting feeling. In addition to calculating the reverberation parameter and the reverberation time to evaluate the hitting feeling, a golfer may actually swing a golf club to hit a ball and evaluate the hitting feeling by listening to the hitting sound at that time.

[0045] (5) Total score The total score was obtained by summing up the above-mentioned four indexes of CT value, high initial velocity area, durability, and hitting feeling. The total score of the experimental example corresponding to the comparative example (Experimental Example 1) was set to 400, indicating that the larger the total score, the better the evaluation.

[0046] The golf club head 10 of the following experimental examples will be described. Experimental Example 1 is a comparative example and does not satisfy the provisions of Claim 1 of the present invention. Experimental Example 1 corresponds to Patent Document 1, and in a hollow wood-type golf club head 10 (driver), an elastic plate is provided in contact with the back surface 14B of the face. Therefore, in Experimental Example 1, when the face portion 14 is deformed by hitting the ball, the elastic plate inhibits the deformation of the face portion 14 by applying a load to the back surface 14B of the face. The specifications of each part of Experimental Example 1 are as follows. Material of the head body 12: Titanium alloy Ti-8Al-1Mo-1V Material of the face portion 14: Ti-6Al-4V Loft angle 10.5° Lie angle 59° Head volume 460 cc

[0047] The golf club head 10 used in Experimental Examples 2-21 corresponds to the present invention, is a hollow-type driver, and has the following common specifications except for the parameters defined in each experimental example. Material of the head body 12: Titanium alloy Ti-8Al-1Mo-1V Material of the face portion 14: Ti-6Al-4V Loft angle 10.5° Lie angle 59° Head volume 460 cc Specifically, Experimental Example 2-21 satisfies the provisions of Claim 1 and includes the contact member 32. In addition, Experimental Example 2-21 satisfies the provisions of Claims 11 and 12. From the contact portion 34 to each leg portion, it extends obliquely with respect to the normal line of the face back surface 14B, and each leg portion extends from locations of the contact portion 34 that are separated from each other. Experimental Example 2-18 is provided with the metal first contact member 32A shown in FIGS. 13(A) and 14. Experimental Example 19 is provided with the third contact member 32C shown in FIG. 13(B). Experimental Example 20 is provided with the fourth contact member 32D and the intermediate member 52A shown in FIG. 20. Experimental Example 21 is provided with the fifth contact member 32E and the intermediate member 52B shown in FIG. 21.

[0048] (Condition 1) For each of Experimental Examples 2-4, as shown in FIG. 22, the conditions defined in Claim 2 were changed. Note that the conditions defined in Claims 3-8 were set as the conditions shown below. The materials of the main body 44 and the support 46 defined in Claim 3 were made the same material. The displacement amount in the toe-heel direction of the contact portion 34 during hitting defined in Claim 4 does not satisfy the condition that it is larger than the displacement amount along the crown-sole direction of the contact portion 34 during hitting. The range where the center point 34P of the contact portion 34 defined in Claim 5 contacts the face back surface 14B is within the range defined by the first plane P1, the second plane P2, the third plane P3, and the fourth plane P4. Specifically, the center point 34P of the contact portion 34 coincides with the center point Pc of the face surface 14A. The area S where the contact portion 34 defined in Claim 5 contacts the face back surface 14B is 25 mm2 as 3 mm 2 ≦S≦400 mm 2 within the range of The thickness Δt2 of the portion of the contact portion 34 defined in claim 5 that is in contact with the face back surface 14B was set to 2 mm and within the range of 1 mm ≦ Δt2 ≦ 7 mm. The ratio of the thickness defined in claim 6 was set to 1.5 and within the range of 0.5 ≦ Δt1 / Δt2 ≦ 2.0 in formula (1). The intermediate members 52A and 52B defined in claims 7 and 8 were omitted. Note that for experimental example 1 as a comparative example, the conditions defined in claims 3 - 8 were set to values equivalent to those of experimental examples 2 - 4.

[0049] Experimental example 1 is a comparative example and does not satisfy the provisions of claim 1. Each evaluation point was set to 100, and the total score is 400.

[0050] Experimental examples 2 - 4 satisfy the provisions of claim 1. Experimental example 2 satisfies the condition that the thickness Δt1 of the leg portions 36 and 38 defined in claim 2 < the thickness Δt2 of the contact portion 34. Experimental examples 3 and 4 do not satisfy the condition that the thickness Δt1 of the leg portions 36 and 38 defined in claim 2 < the thickness Δt2 of the contact portion 34.

[0051] Therefore, as shown in Fig. 22, experimental examples 2 - 4 that satisfy the provisions of claim 1 exceed experimental example 1 whose CT value, high initial velocity area, durability, hitting feeling, and total score are outside the scope of the present invention. In addition, experimental example 2 that satisfies the provisions of claims 1 and 2 has a CT value, high initial velocity area, durability, hitting feeling, and total score that are equal to or higher than those of experimental examples 3 and 4 that do not satisfy the provisions of claim 2.

[0052] (Condition 2) For each experimental example, as shown in Fig. 23, the conditions defined in claim 4 were changed. Note that the conditions defined in claims 2, 3, 5 - 8 were set to the conditions shown below. It was assumed that the thickness Δt1 (1.0 mm) of the leg portions 36 and 38 defined in claim 2 < the thickness Δt2 (3.0 mm) of the contact portion 34 was satisfied. The materials of the main body 44 and the support 46 defined in claim 3 are the same material. The range where the center point 34P of the contact part 34 defined in claim 5 contacts the face back surface 14B is within the range defined by the first plane P1, the second plane P2, the third plane P3, and the fourth plane P4. Specifically, the center point 34P of the contact part 34 is made to coincide with the center point Pc of the face surface 14A. The area S where the contact part 34 defined in claim 5 contacts the face back surface 14B is 25 mm 2 and, 3 mm 2 ≤ S ≤ 400 mm 2 is within the range. The wall thickness Δt2 of the part of the contact part 34 where the contact part 34 defined in claim 5 contacts the face back surface 14B is 2 mm and is within the range of 1 mm ≤ Δt2 ≤ 7 mm. The ratio of the wall thickness defined in claim 6 is 1.5 and is within the range of 0.5 ≤ Δt1 / Δt2 ≤ 2.0 in formula (1). The intermediate members 52A and 52B defined in claims 7 and 8 are not provided. In Experimental Example 5, the displacement amount of the contact part 34 in the toeheel direction during hitting, as defined in claim 4, satisfies the condition that it is larger than the displacement amount of the contact part 34 along the crownsole direction during hitting. Note that in the figure, the symbol × indicates that the condition is not satisfied, and the symbol ○ indicates that the condition is satisfied.

[0053] Therefore, as shown in FIG. 23, Experimental Example 5 that satisfies all the provisions of claims 1, 2, and 4 is excellent in CT value, high initial velocity area, durability, hitting feeling, and total score compared to Experimental Example 2 that satisfies the provisions of claims 1 and 2 but does not satisfy the provisions of claim 4.

[0054] (Condition 3) For each experimental example, as shown in FIG. 24, the conditions defined in claims 5 and 6 were changed. Note that the conditions defined in claims 2 - 4, 7, and 8 are the conditions shown below. The wall thickness Δt1 (1.0 mm) of the leg parts 36 and 38 defined in claim 2 satisfies Δt1 (1.0 mm) < the wall thickness Δt2 (3.0 mm) of the contact part 34. The materials of the main body 44 and the support 46 defined in claim 3 are the same material. The displacement amount in the toeheel direction of the contact portion 34 during hitting defined in claim 4 satisfies the condition that it is larger than the displacement amount along the crownsole direction of the contact portion 34 during hitting. The intermediate members 52A and 52B defined in claims 7 and 8 are not provided.

[0055] In Experimental Example 6, the position in the toeheel direction where the center point 34P of the contact portion 34 defined in claim 5 contacts the face back surface 14B is a location 23 mm away from the center point Pc of the face surface 14A in the toe direction, and the position in the crownsole direction where the center point 34P of the contact portion 34 contacts the face back surface 14B coincides with the center point Pc of the face surface 14A, and it is outside the range defined by the first plane P1, the second plane P2, the third plane P3, and the fourth plane P4. Note that in the figure, T23 / 0 indicates that the center point is 23 mm away in the toe direction and coincides with the center point Pc in the crownsole direction. In Experimental Example 6, the area S where the contact portion 34 defined in claim 5 contacts the face back surface 14B is 1 mm 2 and is outside the range of 3 mm 2 or more and 400 mm 2 or less. In Experimental Example 6, the thickness Δt2 of the portion of the contact portion 34 where the contact portion 34 defined in claim 5 contacts the face back surface 14B is 3.8 mm, and it is outside the range of 1 mm ≤ Δt ≤ 7 mm. In Experimental Example 6, when the thickness of the face portion 14 corresponding to the portion of the face back surface 14B where the contact portion 34 defined in claim 6 abuts is defined as the thickness Δt1, Δt1 / Δt2 is 3.8, and it does not satisfy the following formula (1). 0.5 ≤ Δt1 / Δt2 ≤ 2.0 (1)

[0056] In Experimental Example 7, the position in the toe-heel direction where the center point 34P of the contact portion 34 defined in claim 5 contacts the face back surface 14B is a location 23 mm away from the center point Pc of the face surface 14A in the heel direction, and the position in the crown sole direction where the center point 34P of the contact portion 34 contacts the face back surface 14B coincides with the center point Pc of the face surface 14A, and it is set outside the range defined by the first plane P1, the second plane P2, the third plane P3, and the fourth plane P4. Note that in the figure, H23 / 0 indicates that the center point is 23 mm away in the heel direction and coincides with the center point Pc in the crown sole direction. In Experimental Example 7, the area S where the contact portion 34 defined in claim 5 contacts the face back surface 14B is 420 mm 2 and is outside the range of more than 3 mm 2 and less than 400 mm 2 In Experimental Example 7, the thickness Δt2 of the portion of the contact portion 34 where the contact portion 34 defined in claim 5 contacts the face back surface 14B is set to 0.4 mm and is outside the range of 1 mm ≤ Δt ≤ 7 mm. In Experimental Example 7, Δt1 / Δt2 defined in Experimental Example 6 is 0.4 and does not satisfy the following formula (1). 0.5 ≤ Δt1 / Δt2 ≤ 2.0 (1)

[0057] In Experimental Example 8, the position in the toe-heel direction where the center point 34P of the contact portion 34 defined in claim 5 contacts the face back surface 14B is a location 18 mm away from the center point Pc of the face surface 14A in the toe direction, and the position in the crown sole direction where the center point 34P of the contact portion 34 contacts the face back surface 14B coincides with the center point Pc of the face surface 14A, and it is set within the range defined by the first plane P1, the second plane P2, the third plane P3, and the fourth plane P4. In Experimental Example 8, the area S where the contact portion 34 defined in claim 5 contacts the face back surface 14B is 5 mm 2 and is within the range of more than 3 mm 2 and less than 400 mm 2 ​​In Experimental Example 8, the thickness Δt2 of the portion of the contact portion 34 defined in claim 5 that contacts the back face 14B of the face was set to 2.0 mm, within the range of 1 mm ≤ Δt ≤ 7 mm. In Experimental Example 8, Δt1 / Δt2 defined in claim 6 was 2.0, and it was made to satisfy the following formula (1). 0.5 ≤ Δt1 / Δt2 ≤ 2.0 (1)

[0058] In Experimental Example 9, the position in the toe - heel direction where the center point 34P of the contact portion 34 defined in claim 5 contacts the back face 14B of the face is a position 18 mm away from the center point Pc of the face surface 14A in the heel direction, and the position in the crown - sole direction where the center point 34P of the contact portion 34 contacts the back face 14B of the face coincides with the center point Pc of the face surface 14A, within the range defined by the first plane P1, the second plane P2, the third plane P3, and the fourth plane P4. In Experimental Example 9, the area S where the contact portion 34 defined in claim 5 contacts the back face 14B of the face is 380 mm 2 and is within the range of 3 mm 2 or more and 400 mm 2 or less. In Experimental Example 9, the thickness Δt2 of the portion of the contact portion 34 defined in claim 5 that contacts the back face 14B of the face was set to 6.0 mm, within the range of 1 mm ≤ Δt ≤ 7 mm. In Experimental Example 9, Δt1 / Δt2 defined in claim 6 was 0.5, and it was made to satisfy the following formula (1). 0.5 ≤ Δt1 / Δt2 ≤ 2.0 (1)

[0059] Therefore, as shown in FIG. 24, Experimental Examples 8 and 9 that satisfy all the provisions of claims 1, 2, 4 - 6 have CT values, high - initial - velocity areas, durability, hitting feeling, and total scores within the scope of the present invention, but exceed Experimental Examples 6 and 7 that do not satisfy the provisions of claims 5 and 6.

[0060] (Condition 4) For each experimental example, as shown in FIG. 25, the conditions defined in claim 7 were changed. Note that the conditions defined in claims 2 - 6 and 8 were the conditions shown below. The thickness Δt1 (1.0 mm) of the leg portions 36 and 38 defined in claim 2 satisfies Δt1 < the thickness Δt2 (3.0 mm) of the contact portion 34. The materials of the main body 44 and the support 46 defined in claim 3 are the same material. The displacement amount in the toe - heel direction of the contact portion 34 during hitting defined in claim 4 satisfies the condition that it is larger than the displacement amount along the crown - sole direction of the contact portion 34 during hitting. The range where the center point 34P of the contact portion 34 defined in claim 5 contacts the back surface 14B of the face is within the range defined by the first plane P1, the second plane P2, the third plane P3, and the fourth plane P4. Specifically, the center point 34P of the contact portion 34 coincides with the center point Pc of the face surface 14A. The area S where the contact portion 34 defined in claim 5 contacts the back surface 14B of the face is 25 mm 2 to 2 3 mm 2 ≦ S ≦ 400 mm The thickness Δt2 of the portion of the contact portion 34 where the contact portion 34 defined in claim 5 contacts the back surface 14B of the face is 2 mm, and is within the range of 1 mm ≦ Δt2 ≦ 7 mm. The ratio of the thickness defined in claim 6 is 1.5, and is within the range of 0.5 ≦ Δt1 / Δt2 ≦ 2.0 in formula (1). The spherical intermediate member 52B defined in claim 8 is not provided.

[0061] Experimental Example 10 - 17 is provided with a plate - shaped intermediate member 52A made of an elastomer (Figure 20). In Experimental Example 10, the thickness Δtp of the intermediate member 52A defined in claim 7 is 0.05 mm, which is outside the range of 0.5 mm ≦ Δtp ≦ 5.0 mm. In Experimental Example 10, the elastic modulus E of the intermediate member 52A defined in claim 7 is 0.5 GPa, which is outside the range of 1 GPa ≦ E ≦ 50 GPa. In Experimental Example 11, the thickness Δtp of the intermediate member 52A defined in claim 7 is 6.0 mm, which is outside the range of 0.5 mm ≦ Δtp ≦ 5.0 mm. In Experimental Example 11, the elastic modulus E of the intermediate member 52A defined in claim 7 was set to 0.5 GPa, outside the range of 1 GPa ≤ E ≤ 50 GPa.

[0062] In Experimental Example 12, the thickness Δtp of the intermediate member 52A defined in claim 7 was set to 1.0 mm, within the range of 0.5 mm ≤ Δtp ≤ 5.0 mm. In Experimental Example 12, the elastic modulus E of the intermediate member 52A defined in claim 7 was set to 0.5 GPa, outside the range of 1 GPa ≤ E ≤ 50 GPa. In Experimental Example 13, the thickness Δtp of the intermediate member 52A defined in claim 7 was set to 4.7 mm, within the range of 0.5 mm ≤ Δtp ≤ 5.0 mm. In Experimental Example 13, the elastic modulus E of the intermediate member 52A defined in claim 7 was set to 0.5 GPa, outside the range of 1 GPa ≤ E ≤ 50 GPa.

[0063] In Experimental Example 14, the thickness Δtp of the intermediate member 52A defined in claim 7 was set to 3.0 mm, within the range of 0.5 mm ≤ Δtp ≤ 5.0 mm. In Experimental Example 14, the elastic modulus E of the intermediate member 52A defined in claim 7 was set to 0.4 GPa, outside the range of 1 GPa ≤ E ≤ 50 GPa. In Experimental Example 15, the thickness Δtp of the intermediate member 52A defined in claim 7 was set to 3.0 mm, within the range of 0.5 mm ≤ Δtp ≤ 5.0 mm. In Experimental Example 15, the elastic modulus E of the intermediate member 52A defined in claim 7 was set to 55 GPa, outside the range of 1 GPa ≤ E ≤ 50 GPa.

[0064] In Experimental Example 16, the thickness Δtp of the intermediate member 52A defined in claim 7 was set to 3.0 mm, within the range of 0.5 mm ≤ Δtp ≤ 5.0 mm. In Experimental Example 16, the elastic modulus E of the intermediate member 52A defined in claim 7 was set to 1.3 GPa, within the range of 1 GPa ≤ E ≤ 50 GPa. In Experimental Example 17, the thickness Δtp of the intermediate member 52A defined in claim 7 was set to 3.0 mm, within the range of 0.5 mm ≤ Δtp ≤ 5.0 mm. In Experimental Example 17, the elastic modulus E of the intermediate member 52A defined in claim 7 was set to 48 GPa, within the range of 1 GPa ≤ E ≤ 50 GPa.

[0065] Therefore, as shown in FIG. 25, Experimental Examples 16 and 17 that satisfy all the provisions of claims 1, 2, 4 - 7 have CT values, high initial velocity areas, durability, hitting feelings, and total scores within the scope of the present invention, but exceed Experimental Examples 10 - 15 that do not satisfy the provisions of claim 7.

[0066] (Condition 5) Experimental examples corresponding to the first, second, fourth, and fifth contact members 32A, 32B, 32D, and 32E are shown in FIG. 26. In addition, the conditions defined in claims 2 and 4 were set as the following conditions. It was ensured that the wall thickness Δt1 (1.0 mm) of the legs 36 and 38 defined in claim 2 is less than the wall thickness Δt2 (3.0 mm) of the contact portion 34. It was ensured that the displacement amount in the toe - heel direction of the contact portion 34 during hitting defined in claim 4 is larger than the displacement amount along the crown - sole direction of the contact portion 34 during hitting. The range in which the center point 34P of the contact portion 34 defined in claim 5 contacts the face back surface 14B is within the range defined by the first plane P1, the second plane P2, the third plane P3, and the fourth plane P4. Specifically, the center point 34P of the contact portion 34 coincides with the center point Pc of the face surface 14A. The area S where the contact portion 34 defined in claim 5 contacts the face back surface 14B is 5 mm 2 or 25 mm 2 and, taking 3 mm 2 ≤ S ≤ 400 mm 2 within the range. The wall thickness Δt2 of the portion of the contact portion 34 where the contact portion 34 defined in claim 5 contacts the face back surface 14B is set to 2 mm to 5 mm, within the range of 1 mm ≤ Δt2 ≤ 7 mm. The ratio of the wall thickness defined in claim 6 is set to 0.5 to 1.5, within the range of 0.5 ≤ Δt1 / Δt2 ≤ 2.0 in formula (1).

[0067] Experimental Example 18 does not include the intermediate members 52A and 52B, and uses the first contact member 32A shown in Fig. 13(A). Experimental Example 19 does not include the intermediate members 52A and 52B, and as shown in Fig. 13(B), uses the second contact member 32B in which the main body 44 and the support portion of the contact portion 34 are formed of different materials. Specifically, the main body 44 is formed of a synthetic resin material, and the support 46 is formed of a metal material. In Experimental Example 19, the wall thickness Δtp represents the wall thickness of the main body 44, the wall thickness tp is set to 0.5 mm, and it is in the range of 0.5 mm ≤ Δtp ≤ 5.0 mm. The elastic modulus E represents the elastic modulus of the main body 44, the elastic modulus E is set to 2 GPa, and it is in the range of 1 GPa ≤ E ≤ 50 GPa. As shown in Fig. 20, Experimental Example 20 uses the fourth contact member 32D and is provided with a rectangular parallelepiped intermediate member 52A. As shown in Fig. 21, Experimental Example 21 uses the fifth contact member 32E and is provided with a spherical intermediate member 52B. In Experimental Examples 20 and 21, the wall thicknesses Δtp of the intermediate members 52A and 52B defined in Claim 7 are set to 3.0 mm and 4.0 mm, and are in the range of 0.5 mm ≤ Δtp ≤ 5.0 mm. The elastic moduli E of the intermediate members 52A and 52B are set to 10 GPa and 20 GPa, and are in the range of 1 GPa ≤ E ≤ 50 GPa.

[0068] As shown in Fig. 26, Experimental Examples 18 - 21 satisfy all or most of the conditions defined in Claims 1 - 7, and each numerical value defined in Claims 1 - 7 is made more suitable compared to the above-described Conditions 1 - 4. Therefore, as shown in Fig. 26, Experimental Examples 18 - 21 exceed other Examples 2 - 17 within the scope of the present invention in terms of CT value, high initial velocity area, durability, hitting feeling, and total score.

[0069] Of course, the present invention is also applicable to golf club heads having various hollow portions such as a driver having a hollow portion, a fairway wood having a hollow portion, and a utility having a hollow portion.

Explanation of Reference Numerals

[0070] 10 Golf club head 12 Head body 14 Face part 14A Face surface 14B Face back surface 16 Crown part 16A Crown surface 16B Crown back surface 18 Sole part 18A Sole surface 18B Sole back surface 20 Side part 20A Side surface 20B Side back surface 19 Leading edge 22 Toe 24 Heel 26 Face back 28 Hollow part 30 Hosel 32 Contact member 32A First contact member 32B Second contact member 32C Third contact member 32D Fourth contact member 32E Fifth contact member 34 Contact part 3402 Contact surface 3410 Frame part 3420 Curved surface 34P Center point of the contact part 36 Upper leg part (leg part) 3602 Upper inclined part 3604 Upper bent part 3606 Upper engaging part 36A, 36B Upper leg part (leg part) 38 Lower leg part (leg part) 3802 Lower inclined part 3804 Lower bent part 3806 Lower engaging part 38A, 38B Lower leg part (leg part) 40 Head body member 4002 Opening 42 Face member 4202 Upper concave part 4204 Concave part 44 Body 46 Support 48 Face member 4802 Engagement part 50 Head body member 5002 Opening 52A, 52B Intermediate member 5202 Intermediate member side contact surface P1 First plane P2 Second plane P3 Third plane P4 Fourth plane

Claims

1. A golf club head comprising a head body including a face portion, a crown portion, a sole portion, and a side portion, wherein an interior surrounded by the face portion, the crown portion, the sole portion, and the side portion is a hollow portion, a contact portion that is movably in contact with the face back surface along the face back surface on the face back surface of the face portion, and a contact member having at least two legs extending in directions away from each other from the contact portion, wherein tips of the respective legs are attached to any one or different locations of the face portion, the crown portion, the sole portion, and the side portion, the two legs have a force for moving the contact portion biased by the two legs following the deformation of the face portion that is smaller than a force for deforming the face portion during a golf stroke, and constantly contact the contact portion with the face back surface with a force of a magnitude that hardly inhibits the deformation of the face portion during a golf stroke, and support the contact portion so that the contact portion can be displaced with respect to the face back surface while constantly contacting the face back surface when the face portion deforms, the contact portion includes a main body that contacts the face back surface and a support that supports the main body and is connected to the leg, wherein the main body and the support are formed of different materials, characterized in that it is a golf club head.

2. A golf club head comprising a head body including a face portion, a crown portion, a sole portion, and a side portion, wherein an interior surrounded by the face portion, the crown portion, the sole portion, and the side portion is a hollow portion, a contact portion that is movably in contact with the face back surface along the face back surface on the face back surface of the face portion, and a contact member having at least two legs extending in directions away from each other from the contact portion, wherein tips of the respective legs are attached to any one or different locations of the face portion, the crown portion, the sole portion, and the side portion, the two legs have a force for moving the contact portion biased by the two legs following the deformation of the face portion that is smaller than a force for deforming the face portion during a golf stroke, and constantly contact the contact portion with the face back surface with a force of a magnitude that hardly inhibits the deformation of the face portion during a golf stroke, and support the contact portion so that the contact portion can be displaced with respect to the face back surface while constantly contacting the face back surface when the face portion deforms, An intermediate member made of an elastomer or synthetic resin material is provided between the contact portion and the face back surface and is displaced integrally with the contact portion. The contact of the contact portion with the face back surface is made via the intermediate member. The thickness of the intermediate member is 0.5 mm or more and 5.0 mm or less. The elastic modulus of the intermediate member is 1 GPa or more and 50 GPa or less. A golf club head characterized by the above.

3. The intermediate member has a spherical shape. The contact portion has a spherical curved surface that supports the intermediate member. The golf club head according to claim 2, characterized by the above.

4. The thickness of the contact portion is formed to be larger than the thickness of the leg portion. The golf club head according to claim 1 or 2, characterized by the above.

5. The amount of displacement of the contact portion in the toe-heel direction during hitting is larger than the amount of displacement of the contact portion along the crown-sole direction during hitting. The golf club head according to any one of claims 1 to 4, characterized by the above.

6. In a reference state where the golf club head is installed at a predetermined lie angle and loft angle with respect to the horizontal plane, a cross section obtained by breaking the head body with a plane that includes the normal line passing through the center point of the face surface and is orthogonal to the horizontal plane is defined as the face center reference cross section. A first plane is defined as a plane parallel to the face center reference cross section and spaced 20 mm in the toe direction from the face center reference cross section. A second plane is defined as a plane parallel to the face center reference cross section and spaced 20 mm in the heel direction from the face center reference cross section. A third plane is defined as a plane parallel to the horizontal plane and spaced 15 mm in the crown portion direction from the center point. When a fourth plane is defined as a plane parallel to the horizontal plane and spaced 15 mm in the sole portion direction from the center point, The contact portion abuts on the face back surface within a range defined by the first plane, the second plane, the third plane, and the fourth plane with the center point of the contact portion. The area where the contact portion abuts against the back surface of the face is 3 mm ２ or more and 400 mm ２ or less, and The thickness Δt2 of the portion of the contact portion where the contact portion abuts on the face back surface is 1 mm or more and 7 mm or less. The golf club head according to any one of claims 1 to 5, characterized by the above.

7. Let the thickness of the face portion corresponding to the portion of the face back surface where the contact portion abuts be the thickness Δt1, When the thickness of the portion of the contact portion where the contact portion is in contact with the face back surface is the thickness Δt2, the following formula (1) is satisfied. The golf club head according to any one of claims 1 to 6, characterized in that... 0.5 ≤ Δt1 / Δt2 ≤ 2.0 (1)

8. The attachment of the tip of the leg portion to any one of the face portion, the crown portion, the sole portion, and the side portion is performed by any one of welding, adhesion, brazing, and screwing. The golf club head according to any one of claims 1 to 7, characterized in that...

9. The contact member is formed of any one of a metal material, a fiber-reinforced resin material, a synthetic resin material, and an elastomer. The golf club head according to any one of claims 1 to 8, characterized in that...

10. Each of the leg portions extends obliquely from the contact portion with respect to the normal line of the back surface of the face. The golf club head according to any one of claims 1 to 9, characterized in that...

11. The at least two leg portions extend from positions on the contact portion that are separated from each other. The golf club head according to any one of claims 1 to 10, characterized in that...

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