Golf club head

Abstract

To improve flight distance by ensuring a deflection amount of a face portion, while enhancing the degree of freedom in adjusting a loft angle, a lie angle or a face angle.SOLUTION: By selectively positioning a rotational position of a sleeve 16 relative to a hosel hole 1402 at one of four rotational positions by means of a rotational position determining portion 20, at least two of the loft, lie and face angles can be adjusted. In addition, a central axis Ln of a screw insertion portion 24 is spaced apart in the face-back direction by 1.0 mm or more but less than 8.0 mm from a central axis Lh of the hosel hole 1402, and a location Pn of a screw-insertion wall portion 26 closest to the face portion 30 is spaced apart in the face-back direction by 1.0 mm or more but less than 14.0 mm from a location Ph of a bottom wall 1404 of the hosel portion 14 closest to the face portion 30.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a golf club head in which the loft angle, lie angle, or face angle can be adjusted. [Background technology]

[0002] Various golf club heads have been proposed that allow adjustment of the loft angle, lie angle, or face angle. The present applicant has already proposed the following golf club as such (see Patent Document 1). This golf club head has a shaft hole into which a shaft is inserted and fixed, and is provided with a sleeve such that when inserted into the hosel hole, the central axis of the shaft hole is inclined relative to the central axis of the hosel hole in the hosel section of the head body, and is also provided with a rotational position determining section that selectively determines the rotational position of the sleeve relative to the hosel hole to one of two rotational positions. The sleeve and hosel portion are fastened with a fixing screw at one rotational position selectively positioned from two rotational positions by the rotational position positioning portion, and the loft angle, lie angle, or face angle can be adjusted by changing the relative rotational position of the sleeve with respect to the hosel hole. In addition, in this golf club head, the screw insertion wall portion through which the fixing screw is inserted is spaced a predetermined distance from the face portion in the face-back direction, and the bottom wall of the hosel portion is spaced a predetermined distance from the face portion in the face-back direction, thereby ensuring the amount of deflection of the face portion and improving the flight distance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5748017 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned conventional technology, only one of the loft angle, lie angle, or face angle can be adjusted in two stages, and the remaining two angles are fixed, which limits the degree of freedom in adjusting the angles. The present invention has been made in consideration of the above circumstances, and its purpose is to provide a golf club head that is advantageous in terms of improving the degree of freedom in adjusting the loft angle, lie angle, or face angle while ensuring the amount of deflection of the face portion and improving the flight distance. [Means for solving the problem]

[0005] In order to achieve the above object, one embodiment of the present invention is a golf club head including a head body to which a shaft is attached, the golf club head including: a hosel portion provided in the head body and having a hosel hole; a sleeve having a shaft hole into which the shaft is inserted and fixed, the central axis of the shaft hole being inclined with respect to the central axis of the hosel hole when inserted into the hosel hole; a rotation position determining portion that selectively determines a rotation position of the sleeve relative to the hosel hole to one of N rotation positions (N is an integer of 3 or more); N female thread portions that are arranged on the sleeve around the central axis of the shaft hole and that are provided corresponding to the N rotation positions; a single screw insertion hole that is formed through a bottom wall of the hosel portion that forms the bottom surface of the hosel hole; and a screw thread extending from the bottom wall portion around the screw insertion hole toward the sole portion so as to expose the screw insertion hole to the sole portion of the head body. The golf club is characterized in that it comprises a cylindrical screw insertion wall portion whose interior is a sole hole, and a fixing screw that fastens the sleeve and the hosel portion by inserting it through the sole hole and the screw insertion hole at one rotation position selectively positioned from N rotation positions by the rotation position positioning portion and screwing into one of the N female thread portions that corresponds to the one rotation position, wherein the central axis of the screw insertion hole is spaced 1.0 mm or more and less than 8.0 mm from the central axis of the hosel hole in the face-back direction, and the point of the screw insertion wall portion closest to the face portion is spaced 1.0 mm or more and less than 14.0 mm from the point of the bottom wall of the hosel portion closest to the face portion in the face-back direction, and at least two angles of the loft angle, lie angle, and face angle can be adjusted by changing the N relative rotation positions of the sleeve with respect to the hosel hole. Further, in one embodiment of the present invention, the rotational position determination portion includes a sleeve-side engaging portion provided at a tip portion of the sleeve and a hosel-side engaging portion provided at the hosel portion, the sleeve-side engaging portion and the hosel-side engaging portion engage with each other when the sleeve is inserted into the hosel hole at the N relative rotational positions with respect to the hosel hole of the sleeve, and couple the sleeve to be immovable in the circumferential direction of the hosel hole, the tip portion of the sleeve is formed as a cylindrical surface, the sleeve-side engaging portion is formed with the N number of engaging grooves extending in the axial direction of the sleeve and formed in an open shape on the radially outer side of the cylindrical surface and at the tip end in the axial direction, an engaging member having a screw insertion portion formed therethrough that communicates with the screw insertion hole is attached to a bottom surface of the hosel hole, and the hosel-side engaging portion is formed by an engaging pin that is provided on the engaging member and engages with the engaging groove, It is characterized by satisfying the following formula (1). 2.4X+1≦Y≦2.4X+3.4 (where X is an integer of 2 or greater) In one embodiment of the present invention, two or more of the engagement pins are provided, each having a cross-sectional shape that matches the cross-sectional shape of the engagement groove. Furthermore, one embodiment of the present invention is characterized in that when the sleeve is inserted into the hosel hole, the rotational position is positioned by the rotational position positioning portion, and the fixing screw is not threaded into the female thread portion, and the sleeve is rotated clockwise and counterclockwise relative to the hosel hole, the play is 0.1 mm or more and 0.8 mm or less, when the maximum amount of movement of the outer peripheral surface of the sleeve relative to the outer peripheral surface of the hosel portion in the circumferential direction is defined as play. In addition, one embodiment of the present invention is characterized in that when the sleeve is inserted into the hosel hole and the rotational position of the sleeve is positioned by the rotational position positioning portion, the inclination angle α of the central axis of the shaft hole with respect to the central axis of the hosel hole is greater than or equal to 0.5 degrees and less than 2.5 degrees. In one embodiment of the present invention, the face progression of the head body is 15 mm or more and 25 mm or less. Furthermore, one embodiment of the present invention is a golf club head comprising: a head body to which a shaft is attached, the head body including a hosel portion having a hosel hole; a sleeve having a shaft hole into which the shaft is inserted and fixed, the sleeve having a central axis inclined with respect to the central axis of the hosel hole when inserted into the hosel hole; a rotational position determining unit that selectively determines a rotational position of the sleeve relative to the hosel hole to one of N rotational positions (N is an integer of 2 or more); and a fixing screw that fastens the sleeve and the hosel portion to the one rotational position selectively determined from the N rotational positions by the rotational position determining unit, wherein the loft angle, lie angle, or face angle is adjusted by changing the rotational position of the sleeve relative to the hosel hole, and the hosel portion is configured to include a substantially cylindrical hosel wall portion that is connected to the head body and forms the hosel hole, and a notch portion is formed in a portion of the hosel wall portion located on the back face side. [Effects of the Invention]

[0006] According to one embodiment of the present invention, the rotational position determining unit selectively determines the rotational position of the sleeve relative to the hosel hole to one of N (N≧3) rotational positions, thereby adjusting at least two angles among the loft angle, lie angle, and face angle, which is advantageous in improving the degree of freedom in adjusting the loft angle, lie angle, and face angle. Furthermore, the area where the screw insertion wall portion joins with the face portion can be minimized, or the screw insertion wall portion can be spaced apart from the face portion, which ensures a sufficient amount of deflection of the face portion, thereby improving the flight distance and ensuring a sweet spot. Furthermore, when the outer diameter Y of the sleeve is within the range defined by formula (1), the dimension Z of the thinnest part of the wall between the female thread portion of the sleeve and the cylindrical surface of the sleeve can be ensured to be in the range of 0.2 mm or more and 1.0 mm or less, thereby ensuring the durability of the sleeve and reducing the weight of the sleeve, which is advantageous in ensuring freedom of design of the golf club head. Furthermore, if two or more engaging pins are provided and the engaging pins have a cross-sectional shape that matches the cross-sectional shape of the engaging groove, this is advantageous in ensuring the durability of the engaging member. Furthermore, if the play of the sleeve is 0.1 mm or more and 0.8 mm or less, the sleeve can be smoothly attached to and detached from the hosel hole, and this is advantageous in preventing the fixing screw from loosening due to stress generated when hitting a ball. Furthermore, if the inclination angle α of the central axis Ls of the shaft hole relative to the central axis Lh of the hosel hole is 0.5 degrees or more and 2.5 degrees or less, the adjustment range of the loft angle, lie angle, or face angle can be advantageously kept within appropriate values. Furthermore, if the face progression FP of the head body is set to 15 mm or more and 25 mm or less, the area where the screw insertion wall portion joins the face portion can be minimized while ensuring the depth of the center of gravity, which is more advantageous in improving the flight distance. According to one embodiment of the present invention, the rotational position determining unit selectively determines the rotational position of the sleeve relative to the hosel hole to one of N (N≧2) rotational positions, thereby adjusting the loft angle, lie angle, or face angle. Furthermore, since the cutout portion is formed in the hosel wall, the rigidity of the face portion where the hosel wall portion is connected can be reduced, ensuring the amount of deflection of the face portion, which is advantageous for improving distance and ensuring a sweet spot. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a front view of a golf club head according to a first embodiment. [Figure 2] FIG. 2 is a view taken along the arrow A in FIG. [Figure 3]FIG. 2 is a view taken along arrow B in FIG. [Figure 4] 4 is a cross-sectional view taken along line XX in FIG. 3, showing only the head main body. [Figure 5] FIG. 5 is a cross-sectional view taken along line ZZ in FIG. [Figure 6] FIG. 4 is a cross-sectional view taken along line YY in FIG. 3. [Figure 7] 1A is a perspective view of the sleeve, and FIG. 1B is a bottom view of the sleeve. [Figure 8] FIG. [Figure 9] FIG. [Figure 10] 4 is an explanatory diagram showing the inclination of the center axis of the shaft hole of the sleeve and the center axis of the sleeve (the center axis of the hosel hole). FIG. [Figure 11] 1A is an exploded perspective view of the sleeve, the engaging member, and the fixing screw, and FIG. 1B is an assembled perspective view of the sleeve, the engaging member, and the fixing screw. [Figure 12] 1A is a perspective view of a sleeve in Modification 1, and FIG. 1B is a bottom view of the sleeve. [Figure 13] FIG. 10 is a perspective view of an engaging member in Modification 1. [Figure 14] 10A is an exploded perspective view of a sleeve, an engaging member, and a fixing screw in Modification 2, and FIG. 10B is an assembled perspective view of the sleeve, the engaging member, and the fixing screw. [Figure 15] FIG. 10 is a perspective view of an engaging member in Modification 2. [Figure 16] FIG. 11 is a perspective view of an engaging member in Modification 3. [Figure 17] FIG. 13 is a perspective view of an engaging member in Modification 4. [Figure 18] 3 is a cross-sectional view showing a hosel wall portion inside a head main body according to the first embodiment. FIG. [Figure 19] FIG. 10 is a cross-sectional view showing a hosel wall portion inside a head main body according to a second embodiment. [Figure 20] FIG. 10 is a cross-sectional view showing a hosel wall portion inside a head main body in a first modified example of the second embodiment. [Figure 21]FIG. 10 is a cross-sectional view showing a hosel wall portion inside the head main body in a second modified example of the second embodiment. [Figure 22] FIG. 11 is a cross-sectional view showing a hosel wall portion inside the head main body in a third modified example of the second embodiment. [Figure 23] FIG. 10 is a first explanatory diagram showing a method for defining the center point Pc of the face surface. [Figure 24] FIG. 10 is a second explanatory diagram showing a method for defining the center point Pc of the face surface. [Figure 25] FIG. 10 is a third explanatory diagram showing a method for defining the center point Pc of the face surface. [Figure 26] FIG. 10 is a fourth explanatory diagram showing a method for defining the center point Pc of the face surface. [Figure 27] 2 is a cross-sectional view of a golf club head showing the relationship between a center of gravity G0 of the golf club head and a center of gravity FG on the face surface. FIG. [Figure 28] FIG. 2 is a front view of a golf club head illustrating the definition of a contour line I of the face surface. [Figure 29] FIG. 2 is a cross-sectional view of a golf club head illustrating the definition of a contour line I of the face surface. [Figure 30] FIG. 2 is a front view of a golf club head illustrating the definition of the center point Pc of the face surface. [Figure 31] FIG. 1 is a diagram showing the experimental results of Experimental Examples 1 to 8. [Figure 32] FIG. 10 is a diagram showing the experimental results of Experimental Examples 9 to 16. [Figure 33] FIG. 10 is a diagram showing the experimental results of Experimental Examples 17 to 21. DETAILED DESCRIPTION OF THE INVENTION

[0008] (First embodiment) Next, an embodiment of the present invention will be described with reference to the drawings. In this embodiment, a case will be described in which the golf club head is a hollow wood type golf club head, but the present invention is widely applicable to hollow heads such as hollow irons and hollow utilities.

[0009] As shown in Figures 1 to 6, the golf club head 10 is composed of a head main body 12, a hosel portion 14, a sleeve 16, an engaging member 18, a rotational position determining portion 20, a plurality of female thread portions 22 (see Figure 7), a screw insertion portion 24, a screw insertion wall portion 26, and a fixing screw 28.

[0010] As shown in Figures 1 to 3, the head body 12 is made of metal and includes a face portion 30, a sole portion 32, a crown portion 34, and a side portion 36, and the head body 12 has a hollow structure having a hollow portion formed by the face portion 30, the sole portion 32, the crown portion 34, and the side portion 36. The face portion 30 forms a face surface 30A, has a vertical height, and extends laterally. The sole portion 32 is connected to the lower portion of the face portion 30 and extends rearward. The crown portion 34 connects the upper portion of the face portion 30 and the rear portion of the sole portion 32 . The side portion 36 connects the crown portion 34 and the sole portion 32 . In the drawing, reference numeral 38 denotes a toe, 40 denotes a heel, and S denotes a shaft.

[0011] As shown in Figures 4 to 6, the hosel portion 14 is composed of a hosel wall portion 14A joined to a portion of the face portion 30 closer to the heel 40 and a portion of the side portion 36 closer to the heel 40, and a hosel hole 1402 of a uniform inner diameter is formed inside the hosel wall portion 14A. That is, as shown in FIG. 18, the hosel portion 14 is configured to include a substantially cylindrical hosel wall portion 14A that is connected to the head body 12 and forms a hosel hole 1402. As shown in Figures 4 to 6, the hosel hole 1402 opens at a portion of the crown portion 34 located at the corner between the portion of the face portion 30 closer to the heel 40 and the portion of the side portion 36 closer to the heel 40, and the bottom surface of the hosel hole 1402 is formed by the bottom wall 1404 of the hosel wall portion 14A located at a position above and away from the sole portion 32. As shown in FIG. 5, the bottom wall 1404 has a single screw insertion hole 1406 formed at a location offset from the central axis Lh of the hosel hole 1402 .

[0012] As shown in Figures 6, 7(A), and (B), the sleeve 16 has a small diameter shaft portion 1602, a large diameter shaft portion 1604, a shaft hole 1606, an engagement groove portion 1608, and four female thread portions 22. In this embodiment, the small diameter shaft portion 1602 has cylindrical surfaces 1602A of uniform outer diameter at both axial ends so that it can be inserted into the hosel hole 1402 without rattle, and the axial middle portion of the small diameter shaft portion 1602 is a reduced diameter portion 1610 whose outer diameter is smaller than that of the cylindrical surfaces 1602A. Large diameter shaft portion 1604 is formed coaxially with small diameter shaft portion 1602 at the axial end of small diameter shaft portion 1602, and is formed with a larger outer diameter than small diameter shaft portion 1602. In this embodiment, the outer periphery of large diameter shaft portion 1604 is formed with a conical surface whose outer diameter decreases as it moves away from small diameter shaft portion 1602. An annular abutment surface 1612 is formed at the boundary between the large diameter shaft portion 1604 and the small diameter shaft portion 1602, and as shown in Figure 6, when the small diameter shaft portion 1602 is inserted into the hosel hole 1402, the abutment surface 1612 abuts against the edge of the hosel hole 1402, thereby positioning the sleeve 16 in the axial direction.

[0013] 6, the shaft hole 1606 is formed from the tip of the large diameter shaft portion 1604 to a point near the tip of the small diameter shaft portion 1602, and the bottom surface of the shaft hole 1606 is closed by a wall portion 1614. The shaft hole 1606 is formed with an inner diameter that allows the tip portion of the shaft S (FIG. 1) to be inserted without rattle, and the shaft S is fixed to the sleeve 16 with an adhesive while inserted into the shaft hole 1606.

[0014] 6, the central axis Ls of the shaft hole 1606 does not coincide with the central axis of the cylindrical surface 1602A of the small diameter shaft portion 1602, and the central axis Ls of the shaft hole 1606 is inclined relative to the central axis of the cylindrical surface 1602A. Therefore, when the small diameter shaft portion 1602 of the sleeve 16 is inserted into the hosel hole 1402, the central axis Ls of the shaft hole 1606 is inclined relative to the central axis Lh of the hosel hole 1402.

[0015] The female thread portion 22 is the portion into which the fixing screw 28 is threaded, and as shown in Figures 7(A) and (B), multiple female thread portions 22 are provided at equal intervals around the circumference of the small diameter shaft portion 1602, corresponding to multiple rotational positions. In this embodiment, four female thread portions 22 are formed on a circumference centered on the central axis of the small diameter shaft portion 1602, with a phase shift of 90 degrees in the circumferential direction, and the central axes of these female thread portions 22 are parallel to the central axis of the small diameter shaft portion 1602, and the female thread portions 22 are open at the tip surface of the small diameter shaft portion 1602.

[0016] As shown in Figures 7(A) and (B), multiple engagement grooves 1608 are provided at equal intervals circumferentially on the cylindrical surface 1602A near the tip of the small diameter shaft portion 1602, between multiple female thread portions 22 arranged circumferentially of the small diameter shaft portion 1602. In this embodiment, four engaging grooves 1608 are provided on the cylindrical surface 1602A at intervals of 90° in the circumferential direction. That is, the four female thread portions 22 and the four engagement groove portions 1608 are provided circumferentially of the small diameter shaft portion 1602 with a phase shift of 45 degrees. Each engagement groove 1608 extends in the axial direction of the sleeve 16 and is formed open radially outward of the small diameter shaft portion 1602 and at the axial tip of the small diameter shaft portion 1602, and each engagement groove 1608 constitutes a sleeve side engagement portion 42. As shown in Figure 7(B), each engagement groove portion 1608 has a sleeve-side engagement surface 1616 with a cross-sectional shape that matches the cross-sectional shape of the engagement pin 1804 described later, and in this embodiment, the cross-sectional shape of the sleeve-side engagement surface 1616 cut along an imaginary plane perpendicular to the axial direction of the sleeve 16 is V-shaped.

[0017] As shown in FIG. 8, the engagement member 18 includes a main body plate portion 1802, an engagement pin 1804, and a single screw insertion portion 24. The main body plate portion 1802 is formed in a disk shape with an outer diameter that allows it to be inserted into the hosel hole 1402 without rattle. The screw insertion portion 24 is a portion through which the fixing screw 28 is inserted, and is provided on the main body plate portion 1802 . In this embodiment, the screw insertion portion 24 is formed as a perfect circle having an inner diameter equal to or larger than that of the screw insertion portion 1406 of the bottom wall 1404 of the hosel portion 14 . The screw insertion portion 24 only needs to be able to receive the male threaded portion 2802 of the fixing screw 28 shown in Figure 9, and the screw insertion portion 24 may be formed as a notch that opens radially outward from the main body plate portion 1802. If a notch is provided, the engaging member 18 can be made lighter than when the screw insertion portion 24 is formed as a hole, which is advantageous in reducing the weight of the golf club head 10. As shown in FIG. 6, the main body plate portion 1802 is placed on the bottom wall 1404 of the hosel hole 1402, and is integrally attached to the bottom wall 1404 by welding or adhesive with the screw insertion portion 24 aligned with the screw insertion portion 1406 of the bottom wall 1404.

[0018] In this embodiment, two engagement pins 1804 are provided, and the two engagement pins 1804 are protruded in the thickness direction of the main body plate portion 1802 at a location near the outer periphery of the main body plate portion 1802, away from the screw insertion portion 24, and are shifted in phase by 90 degrees in the circumferential direction of the main body plate portion 1802. The two engagement pins 1804 are arranged to releasably engage with two adjacent engagement grooves 1608 out of the four engagement grooves 1608 when the fixing screw 28 inserted into the screw insertion portion 24 is threaded into the female thread portion 22. The engagement pin 1804 has a V-shaped engagement pin side engagement surface 1806 that engages with the V-shaped sleeve side engagement surface 1616, and a cylindrical surface 1808 that is connected to the V-shaped engagement pin side engagement surface 1806. With the engagement pin side engagement surface 1806 engaged with the sleeve side engagement surface 1616, the cylindrical surface 1602A of the small diameter shaft portion 1602 and the cylindrical surface 1808 of the engagement pin 1804 are continuous and form a single cylindrical surface. The engagement pin side engagement surfaces 1806 of the two engagement pins 1804 engage with the two sleeve side engagement surfaces 1616 of the sleeve 16 , thereby positioning the sleeve 16 in the hosel hole 1402 so that it cannot rotate. The two engagement pins 1804 constitute the hosel side engagement portion 44 . Therefore, the sleeve side engagement portion 42 and the hosel side engagement portion 44 engage with each other when the sleeve 16 is inserted into the hosel hole 1402 at N relative rotational positions relative to the hosel hole 1402 of the sleeve 16, thereby connecting the sleeve 16 so that it cannot move circumferentially around the hosel hole 1402.

[0019] Therefore, in this embodiment, as shown in Figures 6 to 8, the four engagement grooves 1608 of the sleeve 16 and the two engagement pins 1804 of the engagement member 18 form a rotational position determination unit 20 that selectively determines the relative rotational position of the sleeve 16 with respect to the hosel hole 1402 to one of four rotational positions. The engagement pin 1804 has a cross-sectional shape that matches the cross-sectional shape of the engagement groove portion 1608 of the sleeve 16, and as shown in Figure 11, when the engagement groove portion 1608 and the engagement pin 1804 are engaged, the sleeve-side engagement surface 1616 of the engagement groove portion 1608 and the engagement-pin-side engagement surface 1806 of the engagement pin 1804 come into surface contact with each other, which is advantageous in ensuring the strength and durability of the rotational positioning portion 20 formed by the engagement groove portion 1608 and the engagement pin 1804.

[0020] Furthermore, in this embodiment, the use of the sleeve-side engaging portion 42 and the hosel-side engaging portion 44 is advantageous in simplifying the configuration of the rotational position determining portion 20 . Furthermore, since the engaging member 18 that constitutes the hosel side engaging portion 44 is attached to the bottom wall 1404 of the hosel hole 1402, there is no need to perform complex processing on the bottom wall 1404 of the hosel hole 1402, which is advantageous in simplifying the processing of the hosel portion 14.

[0021] As shown in Figure 6, the screw insertion wall portion 26 is cylindrically formed from the bottom wall 1404 around the screw insertion portion 24 toward the sole portion 32 so as to expose the screw insertion portion 24 to the sole portion 32, and the inside of the screw insertion wall portion 26 is a sole hole 46 that is open toward the sole portion 32.

[0022] As shown in Figure 6, the fixing screw 28 is inserted through the sole hole 46, the screw insertion portion 24 of the hosel portion 14, and the screw insertion portion 24 of the engaging member 18 at one rotational position selectively positioned from four rotational positions by the rotational position positioning portion 20, and is threaded into one of the four female thread portions 22 that corresponds to one of the rotational positions, thereby fastening the sleeve 16 and the hosel portion 14 together.

[0023] As shown in FIG. 9, in this embodiment, the fixing screw 28 has a male threaded portion 2802 that screws into the female threaded portion 22, and a head portion 2804 that is provided at the end of the male threaded portion 2802 and has a larger diameter than the male threaded portion 2802, and an engagement groove (not shown) is formed on the upper surface of the head portion 2804 into which a rotating tool such as a screwdriver can be engaged. When the male threaded portion 2802 of the fixing screw 28 is threaded into the female threaded portion 22, a gap is maintained between the tip of the male threaded portion 2802 and the bottom surface of the female threaded portion 22, and the head 2804 abuts against the bottom wall 1404 of the hosel portion 14, thereby fastening the sleeve 16 and the hosel portion 14 together.

[0024] In addition, in this embodiment, as shown in FIG. 7(B), when the outer diameter of the male thread of the fixing screw 28 is X (mm) and the outer diameter of the cylindrical surface 1602A of the sleeve 16 is Y (mm), the following formula (1) is satisfied. 2.4X+1≦Y≦2.4X+3.4 (where X is an integer of 2 or greater) (1) When the outer diameter Y of the sleeve 16 is within the above range, the dimension Z of the thinnest part between the female thread portion 22 of the sleeve 16 and the cylindrical surface 1602A of the sleeve 16 can be ensured to be in the range of 0.2 mm or more and 1.0 mm or less, thereby ensuring the durability of the sleeve 16 and reducing the weight of the sleeve 16, which is advantageous in ensuring freedom of design of the golf club head 10. On the other hand, if the outer diameter Y of the sleeve 16 is below the above range, the wall thickness Z falls below the range of 0.2 mm to 1.0 mm, and therefore the effect of ensuring the durability of the sleeve 16 is reduced. Furthermore, if the outer diameter Y of the sleeve 16 exceeds the above range, the wall thickness Z exceeds the range of 0.2 mm to 1.0 mm, reducing the effect of reducing the weight of the sleeve 16. Furthermore, the outer diameter of the hosel portion 14 also increases, reducing the effect of ensuring the degree of freedom in designing the center of gravity of the golf club head 10.

[0025] As shown in FIGS. 4 and 5, the central axis Ln of the screw insertion portion 24 is spaced apart from the central axis Lh of the hosel hole 1402 in the face-back direction by 1.0 mm or more and less than 8.0 mm. Here, the distance from the central axis Lh to the central axis Ln in the face-back direction is defined as ΔL. The point Pn of the screw insertion wall 26 closest to the face 30 is spaced apart from the point Ph of the bottom wall 1404 of the hosel portion 14 closest to the face 30 by 1.0 mm or more and less than 14.0 mm in the face-back direction. Here, the distance from the point Pn to the point Ph in the face-back direction is defined as ΔP.

[0026] The rotational position positioning unit 20 selectively positions the relative rotational position of the sleeve 16 with respect to the hosel hole 1402 to one of four rotational positions, thereby making it possible to adjust at least two angles from the loft angle, lie angle, and face angle. This is because, as shown in Figures 6 and 10, the shaft hole 1606 into which the shaft S is inserted is arranged so that the central axis Ls of the shaft hole 1606 is inclined with respect to the central axis Lh of the hosel hole 1402 when the small diameter shaft portion 1602 of the sleeve 16 is inserted into the hosel hole 1402.

[0027] In this embodiment, when the sleeve 16 is inserted into the hosel hole 1402 and the rotational position of the sleeve 16 is positioned by the rotational position positioning unit 20, as shown in Figure 10, the inclination angle α of the central axis Ls of the shaft hole 1606 with respect to the central axis Lh of the hosel hole 1402 is not less than 0.5 degrees and not more than 2.5 degrees. If the inclination angle α is within the above range, durability and strength are ensured, and the shaft adhesion margin is within 50 mm and the outer diameter of the sleeve 16 is within 12 mm, which is advantageous in realizing a lightweight sleeve 16 while ensuring the angle adjustment range. If the inclination angle α exceeds the above range, the outer diameter of the sleeve 16 will exceed 12 mm while the shaft adhesion margin is within 50 mm, while ensuring durability and strength. Although the angle adjustment range can be secured, the effect of reducing the weight of the sleeve 16 will be reduced. If the inclination angle α is below the above range, durability and strength can be ensured, but the shaft adhesion margin will be within 50 mm and the outer diameter of the sleeve 16 will be 12 mm or less, which will allow for a lighter sleeve 16, but the angle adjustment range will be too small, reducing the effect of ensuring the angle adjustment range.

[0028] Numerical examples of the loft angle θ and the lie angle φ when the rotational position of the sleeve 16 is changed from the first position to the fourth position are given below. In the following description, the loft angle θ and the lie angle φ at the reference first position are both expressed as 0°. First position (reference position): Lie angle θ = 0°, loft angle φ = 0° Second position: Lie angle θ = 0.75°, loft angle φ = 0.75° 3rd position: Lie angle θ=1.50°, loft angle φ=0° 4th position: Lie angle θ=0.75°, loft angle φ=-0.75° In this example, the case where the loft angle θ and lie angle φ can be adjusted by adjusting the rotational position of the sleeve 16 using the rotational position positioning unit 20 has been described, but it is sufficient to configure the system so that at least two angles of the loft angle θ, lie angle φ, or face angle ω can be adjusted by adjusting the rotational position of the sleeve 16 using the rotational position positioning unit 20.

[0029] Furthermore, in this embodiment, when the sleeve 16 is inserted into the hosel hole 1402 and its rotational position is determined by the rotational position determination portion 20, and the fixing screw 28 is not threaded into the female thread portion 22, and the sleeve 16 is rotated clockwise and counterclockwise relative to the hosel hole 1402, the play is 0.1 mm or more and 0.8 mm or less, where the maximum amount of movement of the outer peripheral surface of the sleeve 16 relative to the outer peripheral surface of the hosel portion 14 is taken as the play. In other words, the maximum amount of circumferential movement of the outer surface of the sleeve 16 relative to the outer surface of the hosel portion 14 when the sleeve 16 is rotated clockwise from a predetermined position is defined as the first play, and the maximum amount of said movement when the sleeve 16 is rotated counterclockwise from the above-mentioned predetermined position is defined as the second play, and the sum of the first play and the second play is the play. If the backlash is within the above range, the sleeve 16 can be smoothly attached to and detached from the hosel hole 1402, and this is advantageous in preventing the fixing screw 28 from loosening due to stress generated when hitting a ball. If the backlash is below the above range, the gap between the sleeve side engagement surface 1610 and the engagement pin side engagement surface 1806 becomes too narrow, and the effect of smoothly attaching and detaching the sleeve 16 to and from the hosel hole 1402 decreases. If the backlash exceeds the above range, the effect of preventing the fixing screw 28 from loosening due to stress generated when hitting a ball decreases.

[0030] The face progression FP of the head body 12 is not less than 15 mm and not more than 25 mm. As shown in Figure 2, the face progression FP is the distance in a direction parallel to the horizontal plane PH between the shaft axis, i.e., the central axis Ls of the shaft hole 1606 of the sleeve 16, and the position F0 of the most distal end of the face surface 30A, in a reference state in which the golf club head 10 is installed according to a predetermined lie angle and loft angle relative to the horizontal plane.

[0031] According to this embodiment, the central axis Ln of the screw insertion portion 24 is spaced apart from the central axis Lh of the hosel hole 1402 in the face-back direction by 1.0 mm or more and less than 8.0 mm, and the point Pn of the screw insertion wall portion 26 closest to the face portion 30 is spaced apart from the point Ph of the bottom wall 1404 of the hosel portion 14 closest to the face portion 30 in the face-back direction by 1.0 mm or more and less than 14.0 mm. That is, when the distance from the central axis Lh to the central axis Ln in the face-back direction is ΔL and the distance from the point Pn to the point Ph in the face-back direction is ΔP, 1.0mm≦ΔL<8.0mm 1.0mm≦ΔP<14.0mm It was decided. Therefore, as shown in FIG. 5, the area where the screw insertion wall portion 26 joins with the face portion 30 can be minimized, or the screw insertion wall portion 26 can be spaced apart from the face portion 30. Therefore, the amount of deflection of the face portion 30 can be secured, which is advantageous in improving the flight distance and securing a sweet spot. If the distances ΔL and ΔP are below the above ranges, it is disadvantageous in terms of ensuring the amount of deflection of the face portion 30, which is disadvantageous in terms of improving the flight distance and ensuring the sweet spot. If the separation distances ΔL and ΔP exceed the above ranges, the amount of deflection of the face portion 30 can be secured, but the inner diameter of the hosel hole 1402 becomes large, and therefore the mass of the hosel portion 14 becomes too heavy, causing the depth of the center of gravity of the head body 12 to become shallow and the launch angle of the ball to decrease, which is disadvantageous in improving the flight distance.

[0032] Furthermore, since the face progression FP of the head body 12 is set to 15 mm or more and 25 mm or less, the area where the screw insertion wall portion 26 joins the face portion 30 can be minimized while ensuring the depth of the center of gravity, which is more advantageous in improving the flight distance. If the face progression FP is less than 15 mm, the distance between the screw insertion wall portion 26 and the face portion 30 becomes shorter, which reduces the effect of minimizing the area where the screw insertion wall portion 26 joins the face portion 30, thereby reducing the amount of deflection and reducing the effect of improving the flight distance. If the face progression FP exceeds 25 mm, the face portion 30 is displaced forward of the head body 12, so the depth of the center of gravity of the head body 12 becomes shallow, the launch angle of the ball becomes low, and the effect of improving the flight distance decreases. In order to enhance the above-mentioned effects, the face progression FP is more preferably 15 mm or more and 20 mm or less, and further preferably 15 mm or more and 18 mm or less.

[0033] Next, Modifications 1 to 4 of the first embodiment will be described. In the modified examples described below and the second embodiment described later, parts and components similar to those in the first embodiment will be given the same symbols and their descriptions will be omitted, with the focus being on the differences. In the first modification shown in FIGS. 12 and 13, the cross-sectional shape of the engagement groove portion 1608 formed on the cylindrical surface 1602A of the sleeve 16 and the cross-sectional shape of the engagement pin 1804 of the engagement member 18 are different from those in the first embodiment. That is, the sleeve-side engagement surface 1616 is a cylindrical surface recessed toward the center axis of the sleeve 16 when viewed in the direction of the center axis of the sleeve 16 . Additionally, the engagement pin side engagement surface 1806 is a cylindrical surface that matches the above cylindrical surface.

[0034] Variation example 2 shown in Figures 14 and 15 differs from the first embodiment in that four engagement pins 1804 are provided circumferentially around the main body plate portion 1802, each shifted by 90 degrees, and that the screw insertion portion 24 of the engagement member 18 is formed as a notch that opens radially outward of the main body plate portion 1802.

[0035] In the third modification shown in FIG. 16, the cross-sectional shape of the two engagement pins 1804 of the engagement member 18 is trapezoidal, and the two engagement pins 1804 are arranged 180 degrees out of phase with each other in the circumferential direction of the main body plate portion 1802, which is different from the first embodiment. That is, the cross-sectional shape of the two engagement pins 1804 is formed by a pair of engagement pin side engagement surfaces 1806 consisting of the remaining surfaces excluding the upper and lower bases of the trapezoid, a cylindrical surface 1810 that constitutes the upper base of the trapezoid, and a cylindrical surface 1812 that constitutes the lower base of the trapezoid. Therefore, although not shown, the cross-sectional shape of the engaging groove 1608 on the cylindrical surface 1602 A of the sleeve 16 also presents substantially the same trapezoidal shape as the engaging pin 1804 .

[0036] Variation example 4 shown in Figure 17 differs from the first embodiment in that the three engagement pins 1804 of the engagement member 18 are provided at three of four locations circumferentially shifted by 90 degrees from one another on the main body plate portion 1802, and that the screw insertion portion 24 of the engagement member 18 is formed as a notch that opens radially outward on the main body plate portion 1802.

[0037] As shown in the above-mentioned variants 1 to 4, as long as the rotational position positioning unit 20 can selectively position one of four rotational positions to one rotational position, the number of engaging pins 1804, the cross-sectional shape of the engaging surface of the engaging pin 1804, and the cross-sectional shape of the engaged surface of the sleeve 16 are arbitrary and are not limited to the above-mentioned embodiments and variants. However, if there is only one engagement pin 1804, the load will be concentrated on that one engagement pin 1804 when the ball is struck, and play will likely increase. Therefore, it is preferable to have two or more engagement pins 1804, as this will allow the load to be distributed among multiple engagement pins 1804 and ensure the durability of the engagement member 18. Furthermore, if the engagement pin 1804 does not have a cross-sectional shape that matches the cross-sectional shape of the engagement groove portion 1608 of the sleeve 16, when the engagement groove portion 1608 and the engagement pin 1804 are engaged, the sleeve side engagement surfaces 1616 on both sides and the engagement pin side engagement surfaces 1806 on both sides will not come into surface contact with each other, and the load will be concentrated, reducing the effect of ensuring the durability of the engagement member 18. Therefore, as in the embodiment, it is advantageous for the engagement pin 1804 to have a cross-sectional shape that matches the cross-sectional shape of the engagement groove portion 1608 of the sleeve 16, because when the engagement groove portion 1608 and the engagement pin 1804 are engaged, the sleeve side engagement surfaces 1616 on both sides of the engagement groove portion 1608 and the engagement pin side engagement surfaces 1806 on both sides of the engagement pin 1804 come into surface contact with each other, thereby ensuring the durability of the engagement member 18.

[0038] In addition, in the first embodiment and the above-mentioned variant example 1-4, a case was described in which the rotational position determining unit 20 selectively determines the relative rotational position of the sleeve 16 with respect to the hosel hole 1402 to one of four rotational positions. However, assuming that the outer diameter of the hosel portion 14 or the sleeve 16 increases, the rotational position positioning unit 20 may selectively position the hosel portion 14 or the sleeve 16 at one of three or more rotational positions, or five or more rotational positions, so that at least two of the loft angle, lie angle, and face angle can be adjusted. In this case, the number of female threads 22 and engaging grooves 1608 provided on the sleeve 16 may be three or five or more, and the same effect as in the embodiment can be achieved.

[0039] (Second embodiment) Next, a second embodiment will be described. As in the first embodiment, in the second embodiment, the golf club head will be described as a hollow wood-type golf club head, but the present invention is widely applicable to hollow heads such as hollow irons and hollow utilities. As shown in Figures 19 to 22, the second embodiment differs from the first embodiment in that cutout portions 48A-48D are formed in the hosel wall portion 14A located on the face-back side inside the head main body 12 of the hosel portion 14, but is otherwise similar to the first embodiment.

[0040] The hosel wall portion 14A has a length along the axial direction of the hosel hole 1402, and in the example shown in Figure 19, a notch portion 48A is formed in the upper half of the hosel wall portion 14A on the face-back side in the longitudinal direction, closer to the crown portion 34. In the example shown in FIG. 20, a notch 48B is formed on the face-back side at the middle portion in the length direction of the hosel wall portion 14A. In the example shown in FIG. 21, a notch 48C is formed on the face-back side over substantially the entire length of the hosel wall 14A in the longitudinal direction. In the example shown in FIG. 22, a notch 48D is formed in the hosel wall 14A over substantially the entire length of the hosel wall 14A except for a portion closer to the face portion 30.

[0041] According to the second embodiment, not only can the same effects as those of the first embodiment be achieved, but also, since the cutout portions 48A-48D are formed in the hosel wall portion 14A, the rigidity of the portion of the face portion 30 where the hosel wall portion 14A is connected can be reduced. Therefore, the amount of deflection of the face portion 30 can be secured, which is advantageous in improving the flight distance and securing a sweet spot. Furthermore, the weight of the head body 12 can be reduced, which is advantageous in terms of ensuring freedom in designing the golf club head 10.

[0042] The position and shape of the cutout portion formed in the hosel wall portion 14A need only be such that the rigidity of the portion of the face portion 30 to which the hosel wall portion 14A is connected can be reduced and the amount of deflection of the face portion 30 can be ensured, and it is needless to say that the position and shape are not limited to those illustrated in Figures 19 to 22.

[0043] In the second embodiment, similarly to the first embodiment, the case where N number of female thread portions 22 are provided on the sleeve 16 has been described. However, the second embodiment can also be applied to a golf club head in which a single female thread portion 22 is provided on the sleeve 16, and the sleeve 16 and the hosel portion 14 are fastened together by threading a fixing screw 28 into the single female thread portion 22 of the sleeve 16 at one rotational position selectively positioned from N rotational positions by the rotational position positioning portion 20, and the loft angle, lie angle, or face angle can be adjusted by changing the rotational position of the sleeve 16 relative to the hosel hole 1402.

[0044] (Definition of the center point Pc of the face surface 30A) Below, experimental examples will be explained, but first, a method for defining the "center point Pc of the face surface 30A" necessary for explaining the test contents will be explained. The center point Pc of the face surface 30A is the geometric center of the face surface 30A, and various conventionally known methods can be used to determine the center point Pc, including the first and second determination methods exemplified below.

[0045] [A] First method for defining the center point Pc of the face 30A: This is a method of defining the center point Pc when there is a clear boundary between the face surface 30A and other parts of the golf club head 10, in other words, when the periphery of the face surface 30A is specified by a ridge line. In this case, the face surface 30A is clearly defined. 23 to 26 are explanatory diagrams showing a method for defining the center point Pc of the face 30A.

[0046] (1) First, as shown in Figure 23, the golf club head 10 is placed on a horizontal plane HP so that the lie angle and face angle are set to specified values. The state of the golf club head 10 at this time is defined as the reference state. The set values ​​of the lie angle and face angle are, for example, values ​​listed in the product catalog.

[0047] (2) Next, a tentative center point c0 in the direction connecting the crown portion 34 and the sole portion 32 is determined. That is, as shown in FIG. 23, a perpendicular line f0 is drawn that intersects with the approximate center point of a line (hereinafter referred to as the horizontal line) that is parallel to a horizontal plane HP connecting the toe 38 and the heel 40. The midpoint between point a0 where this perpendicular line f0 intersects with the upper edge of the face surface 30A and point b0 where the perpendicular line f0 intersects with the lower edge of the face surface 30A is set as a tentative center point c0.

[0048] (3) Next, draw a horizontal line g0 passing through the temporary center point c0 as shown in Figure 24. (4) Next, as shown in Figure 25, the midpoint between point d0 where the horizontal line g0 intersects with the edge of the face surface 30A on the toe 38 side and point e0 where the horizontal line g0 intersects with the edge of the face surface 30A on the heel 40 side is set as the temporary center point c1.

[0049] (5) Next, as shown in Figure 26, a perpendicular line f1 is drawn passing through the provisional center point c1, and the midpoint between point a1 where this perpendicular line f1 intersects with the upper edge of the face surface 30A and point b1 where the perpendicular line f1 intersects with the lower edge of the face surface 30A is set as the provisional center point c2. Here, if the provisional center points c1 and c2 coincide with each other, that point is defined as the center point Pc of the face surface 30A. If the tentative center points c1 and c2 do not match, steps (2) to (5) are repeated. Since the face surface 30A is curved, when determining the midpoint of the horizontal line g0 and the midpoint 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 30A. The face center line CL is defined as a straight line that passes through the center point Pc and extends in a direction perpendicular to the toe-heel direction.

[0050] [B] Second method for defining the center point Pc of the face 30A: Next, the definition of the center point Pc will be described for the case where the periphery of the face surface 30A and other parts of the golf club head 10 are connected by a curved surface and the face surface 30A cannot be clearly defined.

[0051] As shown in Figure 27, the golf club head 10 is hollow, the symbol G0 indicates the center of gravity of the golf club head 10, and the symbol Lp is a straight line connecting the center of gravity G0 and the center of gravity FG on the face surface 30A, in other words, the straight line Lp is a perpendicular line to the face surface 30A 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 30A is the center of gravity FG on the face surface 30A. Here, as shown in FIG. 28, consider a number of planes H1, H2, H3, . . . , Hn that include a straight line Lp that connects the center of gravity G0 and the center of gravity FG on the face surface 30A.

[0052] The radius of curvature r0 of the outer surface of the golf club head 10 is measured at a cross section when the golf club head 10 is cut along each of the planes H1, H2, H3, . . . , Hn, as shown in FIG. When measuring the radius of curvature r0, it is assumed that there are no face lines, punch marks, etc. on the face surface 30A. The radius of curvature r0 is continuously measured from the center point Pc of the face 30A in the outward direction (upward and downward directions in FIG. 29). Then, the portion where the radius of curvature r0 first becomes equal to or smaller than a predetermined value in the measurement is defined as a contour line I representing the periphery of the face surface 30A. The predetermined value is, for example, 200 mm. As shown in FIGS. 28 and 29, the area surrounded by a contour line I determined based on a number of planes H1, H2, H3, . . . , Hn is defined as a face surface 30A.

[0053] Next, as shown in FIG. 30, the golf club head 10 is placed on the horizontal ground (horizontal plane HP) so that the lie angle and face angle are set to the specified values. The straight line LT passes through the point PT on the toe 38 side of the face surface 30A and extends in the vertical direction. The straight line LH passes through the point PH on the heel 40 side of the face surface 30A and extends in the vertical direction. The line LC is parallel to the lines LT and LH. The distance between the lines LC and LT is equal to the distance between the lines LC and LH. The symbol Pu indicates an upper point on the face surface 30A, and the symbol Pd indicates a lower point on the face surface 30A. The upper point Pu and the lower point Pd are both intersections 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 point Pu and the lower point Pd.

[0054] Experimental examples of the present invention will be described below. 31 to 33 are diagrams showing experimental results of the golf club head 10 according to the present invention. A sample golf club head 10 was prepared for each experimental example, and the following four evaluation items were measured to determine indices (evaluation points), and the total score of the four indices was calculated. The sample golf club head 10 had a loft angle of 10.5 degrees, a lie angle of 60 degrees, and a face angle of 0 degrees. The angle adjustment range (loft angle and lie angle) was a maximum of 1.5 degrees. That is, the angle adjustment values ​​were as follows: First position (reference position): Lie angle θ = 0°, loft angle φ = 0° Second position: Lie angle θ = 0.75°, loft angle φ = 0.75° 3rd position: Lie angle θ=1.50°, loft angle φ=0° 4th position: Lie angle θ=0.75°, loft angle φ=-0.75°

[0055] The four evaluation items are as follows: (1) Degree of fitting The degree of fitting was evaluated by 50 subjects (head speed 37-43m / s) who adjusted the angle while making test hits. The higher the probability that each subject found the angle position that best suited them in terms of distance and direction, the higher the index, indicating a good evaluation of the club. The data on the degree of fitting is expressed as an index, with the degree of fitting of the golf club head 10 of Experimental Example 1, which corresponds to the comparative example, being set at 100.

[0056] (2) High initial velocity area (sweet area) Centered on the center point Pc of the face surface 30A, 45 points were set as impact points Pi at equal intervals in the toe-heel direction and the crown-sole direction. A dedicated swing robot was used to swing a golf club at an impact point Pi of 45, and the initial velocity of the golf ball was measured with a measuring device. The head speed was set to 40 m / s. The initial velocity data from 45 impact points was interpolated, and the area of ​​the high initial velocity area on face 30A where the maximum initial velocity of the golf ball was 98% or more was indexed. Note that the data from the impact point above center point Pc (closer to crown 34) and the data from the impact point below center point Pc (closer to sole 32) were weighted more heavily to match the actual impact point location used by golfers. The data for the high initial velocity area is expressed as an index, with the measurement result of the golf club head 10 of Experimental Example 1, which corresponds to a comparative example, being set at 100. The larger the index, the better the evaluation.

[0057] (3) Flying distance The flight distance obtained in the actual hitting test at the above impact point in the initial velocity test was measured. The average flight distance for a total of nine hit points was calculated, and the index for Experimental Example 1, which corresponds to the comparative example, was set to 100, with the larger the index, the longer the flight distance and the better the evaluation.

[0058] (4)Durability The golf ball was repeatedly hit with an air cannon against the face 30A of the golf club head 10 fixed to the shaft, and the number of hits required to cause deformation or damage to the face 30 was measured and indexed. The ball speed was 50 m / s. The impact point was the center point Pc of the face 30A. In this case, the measurement results of the golf club head 10 of Experimental Example 1, which corresponds to a comparative example, are expressed as an index of 100. The larger the index, the better the evaluation.

[0059] (5) Total score The total score was calculated by adding up the four indices mentioned above: degree of fitting, high initial velocity area, flight distance, and durability. The total score of Experimental Example 1, which corresponds to the comparative example, is 400, and the larger the total score, the better the evaluation.

[0060] The experimental conditions will be explained. Experimental Example 1 is a comparative example that does not satisfy the provisions of claims 1 to 3 of the present invention and corresponds to Patent Document 1. The specifications of each part in Experimental Example 1 are as follows: Material of head body 12: Titanium alloy Ti-8Al-1Mo-1V Material of face member 14: titanium alloy Ti-6Al-4V Loft angle 10.5° Lie angle 59° Head weight 200g Head volume 460cc

[0061] The golf club head 10 used in Experimental Examples 2-21 corresponds to the present invention, is a hollow driver, and has the following common specifications except for the parameters specified in each experimental example. Material of head body 12: Titanium alloy Ti-8Al-1Mo-1V Material of face member 14: titanium alloy Ti-6Al-4V Loft angle 10.5° Lie angle 59° Head weight 200g Head volume 460cc In addition, for experimental examples 2-21, the inclination angle α (0.5 degrees or more and 2.5 degrees or less) specified in claim 5 was set to a common value of 0.75°, and the leading edge (15 mm or more and 25 mm or less) specified in claim 6 was set to a common value of 18 mm.

[0062] (Condition 1: Figure 31 / Experimental Example 2-8) Condition 1 is defined as satisfying all the conditions specified in claims 1-6 and the condition specified in claim 7. In addition, in Figure 31 and subsequent figures showing the experimental results, the thickness Z (mm) in the left column corresponds to the dimension Z of the thinnest point between the female thread portion 22 of the sleeve 16 and the cylindrical surface 1602A of the sleeve 16. That is, the item of thickness Z (mm) (0.2≦Z≦1.0) in the left column corresponds to the following formula (1) defined in claim 2. 2.4X+1≦Y≦2.4X+3.4 (where X is an integer of 2 or greater) (1) That is, if formula (1) is satisfied, the thickness Z will be within the above range, and if formula (1) is not satisfied, the thickness Z will be outside the above range.

[0063] Experimental Example 1 is a comparative example, and has two female thread portions, which does not satisfy the provisions of claim 1 of the present invention and is outside the scope of the present invention. Experimental Examples 2 and 3 meet the requirements of claims 1-6 and are within the scope of the present invention. Furthermore, Experimental Examples 4 to 8 satisfy the provisions of claim 7 and are within the scope of the present invention. Here, the conditions of the notched portion in Experimental Example 4-8 in FIG. 31 will be explained. Experimental Example 4: A notch 48A was formed in the upper half of the hosel wall 14A (FIG. 19). Experimental Example 5: A notch was formed in the lower half of the hosel wall portion 14A. Experimental Example 6: A notch 48B was formed in the middle of the hosel wall 14A (FIG. 20). Experimental Example 7: A notch 48D was formed over the entire length of the hosel wall 14A on the side opposite the face portion, that is, the portion closer to the back of the face (FIG. 22). Experimental Example 8: A notch was formed over the entire length of the face portion side of the hosel wall portion 14A. Therefore, compared to Experimental Example 1, Experimental Examples 2 and 3, which satisfy the provisions of claims 1-6, are superior in all of the following: degree of fitting, high initial velocity area, flight distance, durability, and total score. Furthermore, compared to Experimental Example 1, Experimental Examples 4-8, which satisfy the provisions of claim 7, are superior in all of the following: degree of fitting, high initial velocity area, flight distance, durability, and total score, and are superior in high initial velocity area and flight distance compared to Experimental Examples 2 and 3 above.

[0064] (Condition 2: Figure 32 / Experimental Examples 9-16) In condition 2, among the claims 1, those in which the separation distance ΔL and the separation distance ΔP are within the ranges defined by the claims 1 were compared with those in which the separation distance ΔL and the separation distance ΔP are outside the ranges defined by the claims 1 (outside the scope of the present invention). The provisions of claims 1 to 6 other than the distances ΔL and ΔP are the same as those of condition 1, and claim 7 is such that a notch 48A (FIG. 19) is formed in the upper half of the hosel wall 14A. Therefore, compared to Experimental Examples 9-12, which do not satisfy the requirements of the separation distance ΔL and separation distance ΔP in claim 1, Experimental Examples 13-16, which satisfy the requirements, are superior in all aspects of fitting degree, high initial velocity area, flight distance, durability, and total score.

[0065] (Condition 3: Figure 33 / Experimental Examples 17-21) In condition 3, the specification of formula (1) in claim 2 (in other words, the specification of thickness Z), the specification of the number of engaging pins 1804 in claim 3, and the specification of play in claim 4 were evaluated when they were outside their respective ranges. The provisions of claims 1, 4, 5, and 6 are the same as condition 1, and claim 7 is such that a notch 48A (FIG. 19) is formed in the upper half of the hosel wall 14A. Therefore, in Experimental Example 17, which is below the range specified by formula (1) in claim 2 (thickness Z is below the specified range), the evaluation of durability is inferior to Experimental Example 1 because thickness Z is small. Furthermore, experimental example 18, which exceeds the specified range of formula (1) in claim 2 (thickness Z exceeds the specified range), is superior to experimental example 1 in each evaluation, but because thickness Z is large, the weight of sleeve 16 increases, reducing the effect of ensuring freedom in design of golf club head 10. Furthermore, in Experimental Example 19, which does not satisfy the requirement of claim 3 because it has one engaging pin 1804, the fixing screw 28 tends to loosen, and therefore the durability rating is inferior to Experimental Example 1. Furthermore, Experimental Example 20, in which the backlash G is below the stipulation of claim 4, is superior to Experimental Example 1 in all evaluations including durability, but the effect of smoothly attaching and detaching the sleeve 16 to and from the hosel hole 1402 is reduced. Furthermore, experimental example 20, in which the backlash G exceeds the specification of claim 4, has a reduced effect in suppressing loosening of the fixing screw 28 caused by the stress generated when hitting the ball, and therefore its durability is evaluated as inferior to that of experimental example 1. [Explanation of symbols]

[0066] 10. Golf club head 12 Head body 14 Hosel 14A Hosel wall 1402 hosel hole 1404 Bottom wall 1406 Screw insertion hole 16 sleeve 1602 Small diameter shaft 1602A Cylindrical surface 1604 Large diameter shaft 1606 Shaft hole 1608 Engagement groove 1610 Reduced diameter section 1612 Contact surface 1614 Wall 1616 Sleeve side engagement surface 18 Engagement member 1802 Main body plate 1804 Engagement pin 1806 Engagement pin side engagement surface 1808 Cylindrical Surface 1810 Cylindrical surface 1812 Cylindrical Surface 20 Rotation position determining unit 22 Female thread 24 Screw insertion part 26 Screw insertion wall 28 Fixing screw 2802 Male thread 2804 Head 30 Face part 30A face 32 Sole 34 Crown part 36 Side part 38 Tou 40 Heel 42 Sleeve side engagement portion 44 Hosel side engagement portion 46 sole holes 48A-28D cutout

Claims

1. A golf club head having a head body to which a shaft is attached, a hosel portion provided in the head body and having a hosel hole; a sleeve having a shaft hole into which the shaft is inserted and fixed, the central axis of the shaft hole being inclined with respect to the central axis of the hosel hole when the sleeve is inserted into the hosel hole; a rotational position determining unit that selectively determines a rotational position of the sleeve relative to the hosel hole at one of N rotational positions (N is an integer of 3 or more); N female thread portions are arranged on the sleeve around the central axis of the shaft hole and provided corresponding to the N rotation positions; a single screw insertion hole formed through a bottom wall of the hosel portion that forms a bottom surface of the hosel hole; a screw insertion wall portion that is cylindrically formed from the bottom wall portion around the screw insertion hole toward the sole portion so as to expose the screw insertion hole to the sole portion of the head body, the interior of which serves as a sole hole; a fixing screw that fastens the sleeve and the hosel portion together by being inserted through the sole hole and the screw insertion hole and being screwed into one of the N female thread portions that corresponds to the one rotational position, at one rotational position selectively positioned from among N rotational positions by the rotational position positioning portion; a central axis of the screw insertion hole is spaced apart from a central axis of the hosel hole in a face-back direction by 1.0 mm or more and less than 8.0 mm, and a location of the screw insertion wall portion closest to the face portion is spaced apart from a location of the bottom wall of the hosel portion closest to the face portion in a face-back direction by 1.0 mm or more and less than 14.0 mm, At least two angles selected from a loft angle, a lie angle, and a face angle are adjusted by changing the N relative rotational positions of the sleeve with respect to the hosel hole. A golf club head characterized by:

2. the rotational position determining portion includes a sleeve-side engaging portion provided at a tip portion of the sleeve and a hosel-side engaging portion provided at the hosel portion, the sleeve-side engaging portion and the hosel-side engaging portion engage with each other and couple the sleeve to be immovable in a circumferential direction of the hosel hole when the sleeve is inserted into the hosel hole at one of the N relative rotation positions of the sleeve with respect to the hosel hole, The tip of the sleeve is formed with a cylindrical surface, the sleeve-side engaging portion is formed by the N engaging groove portions that extend in the axial direction of the sleeve and are formed in an open state on the radially outer side of the cylindrical surface and at a tip end in the axial direction, an engaging member having a screw insertion portion formed therethrough and communicating with the screw insertion hole is attached to a bottom surface of the hosel hole; the hosel-side engaging portion is formed by an engaging pin that is provided on the engaging member and engages with the engaging groove portion, When the outer diameter of the male thread of the fixing screw is X (mm) and the outer diameter of the cylindrical surface of the sleeve is Y (mm), 2. The golf club head according to claim 1, wherein the following formula (1) is satisfied: 2.4X + 1 ≦ Y ≦ 2.4X + 3.4 (where X is an integer of 2 or more) (1)

3. Two or more of the engagement pins are provided, and each has a cross-sectional shape that matches the cross-sectional shape of the engagement groove portion.

3. The golf club head according to claim 2.

4. When the sleeve is inserted into the hosel hole and the rotational position is determined by the rotational position determining portion, and the fixing screw is not threaded into the female thread portion, When the sleeve is rotated clockwise and counterclockwise with respect to the hosel hole, the maximum value of the amount of movement of the outer peripheral surface of the sleeve relative to the outer peripheral surface of the hosel portion in the circumferential direction is defined as a backlash, and the backlash is 0.1 mm or more and 0.8 mm or less.

2. The golf club head according to claim 1.

5. When the sleeve is inserted into the hosel hole and the rotational position of the sleeve is determined by the rotational position determining portion, an inclination angle α of the central axis of the shaft hole with respect to the central axis of the hosel hole is 0.5 degrees or more and 2.5 degrees or less; 2. The golf club head according to claim 1.

6. a face progression of the head body is 15 mm or more and 25 mm or less; 6. The golf club head according to claim 1, wherein the first and second shafts are arranged parallel to each other.

7. A head body to which a shaft is attached is provided, a hosel portion provided in the head body and having a hosel hole; a sleeve having a shaft hole into which the shaft is inserted and fixed, the central axis of the shaft hole being inclined with respect to the central axis of the hosel hole when the sleeve is inserted into the hosel hole; a rotational position determining unit that selectively determines a rotational position of the sleeve relative to the hosel hole at one of N rotational positions (N is an integer of 2 or more); a fixing screw that fastens the sleeve and the hosel portion together at one rotational position selectively positioned by the rotational position positioning unit from among N rotational positions, A golf club head configured so that a loft angle, a lie angle, or a face angle can be adjusted by changing a rotational position of the sleeve relative to the hosel hole, the hosel portion is configured to include a substantially cylindrical hosel wall portion connected to the head body and forming the hosel hole, a notch is formed in the hosel wall portion located on the face back side; A golf club head characterized by:

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