The present application claims priority to Japanese Patent Application No. 2021-017094 filed on Feb. 5, 2021. The entire contents of this Japanese Patent Application are hereby incorporated by reference.
The present disclosure relates to a golf club head.
There has been known a golf club head including a face member and a head body that are welded to each other. There also has been known a golf club head including a face member that has a cup face structure. JP2020-191938 A (US2020/0368590 A1) discloses a golf club head including a head body and a face member having a peripheral portion that are joined to each other by welding. In this head, the peripheral portion includes a thick portion joined to an end surface of an opening of the head body, and a connecting portion connecting the thick portion and a face portion. The connecting portion includes a thin portion that has a thinner wall thickness than that of the thick portion.
There has been demand for a head having a higher rebound performance. The inventors of the present disclosure have found a new structure capable of enhancing rebound performance in a head including a face member and a body member that are joined to each other. The inventors of the present disclosure have found that the rebound performance of the head can be improved by increasing the rigidity of a portion that is easy to bend in a conventional head structure and by shifting the position of bending of the head. One of the objects of the present disclosure is to provide a golf club head having an enhanced rebound performance achieved with a new structure.
In one aspect, the present disclosure provides a golf club head having a head outer surface and a head inner surface, and being hollow. The head includes a body member having an opening, and a face member including a striking face and closing the opening. The face member includes a face portion that forms the striking face, and a peripheral portion that extends from a peripheral edge of the face portion toward a back side. The peripheral portion of the face member is welded to the body member. A weld bead that juts from the head inner surface is formed at a boundary position between the peripheral portion and the body member. A wall thickness at a face-side end point of the weld bead is greater than a wall thickness at a body-side end point of the weld bead. The peripheral portion has a length of less than or equal to 6 mm.
Hereinafter, the present disclosure will be described in detail according to the preferred embodiments with appropriate references to the accompanying drawings.
In the present disclosure, a reference state, a reference perpendicular plane, a toe-heel direction, a face-back direction, an up-down direction, a face center, a vertical cross section, and a radius of curvature are defined as follows.
The reference state is defined as a state where a head is placed at a predetermined lie angle on a ground plane HP. As shown in
In the reference state, a face angle is 0°. That is, in a planer view of the head as viewed from above, a tangent line to the head at its face center on a striking face is set to be parallel to the toe-heel direction. The definitions of the face center and the toe-heel direction are as explained below.
In the present disclosure, the toe-heel direction is the direction of an intersection line NL between the reference perpendicular plane VP and the ground plane HP (see
In the present disclosure, the face-back direction is a direction that is perpendicular to the toe-heel direction and is parallel to the ground plane HP. A face side in the face-back direction is also simply referred to as “face side”. A back side in the face-back direction is also simply referred to as “back side”.
In the present disclosure, the up-down direction is a direction that is perpendicular to the toe-heel direction and is perpendicular to the face-back direction. In other words, the up-down direction in the present disclosure is a direction perpendicular to the ground plane HP.
In the present disclosure, the face center is determined in the following manner. First, a point Pr is selected roughly at the center of a striking face in the up-down direction and the toe-heel direction. Next, a plane that passes through the point Pr, extends in the direction of a line normal to the striking face at the point Pr, and is parallel to the toe-heel direction is determined. An intersection line between this plane and the striking face is drawn, and a midpoint Px of this intersection line is determined. Next, a plane that passes through the midpoint Px, extends in the direction of a line normal to the striking face at the midpoint Px, and is parallel to the up-down direction is determined. An intersection line between this plane and the striking face is drawn, and a midpoint Py of this intersection line is determined. Next, a plane that passes through the midpoint Py, extends in the direction of a line normal to the striking face at the midpoint Py, and is parallel to the toe-heel direction is determined. An intersection line between this plane and the striking face is drawn, and a midpoint Px of this intersection line is newly determined. Next, a plane that passes through this newly-determined midpoint Px, extends in the direction of a line normal to the striking face at this midpoint Px, and is parallel to the up-down direction is determined. An intersection line between this plane and the striking face is drawn, and a midpoint Py of this intersection line is newly determined. By repeating the above-described steps, points Px and Py are sequentially determined. In the course of repeating these steps, when the distance between a newly-determined midpoint Py and a midpoint Py determined in the immediately preceding step first becomes less than or equal to 0.5 mm, the newly-determined midpoint Py (the midpoint Py determined last) is defined as the face center.
In the present disclosure, the vertical cross section is defined as each of cross sections taken along respective planes perpendicular to the toe-heel direction. The vertical cross section is parallel to the face-back direction. The vertical cross section is perpendicular to the ground plane HP. A contour line shown in the vertical cross section is also referred to as a vertical cross-sectional contour line. The vertical cross section can be set at each position in the toe-heel direction.
A radius of curvature of a curved surface is measured in the vertical cross section. That is, the radius of curvature of a curved surface is measured in the vertical cross-sectional contour line. The vertical cross section is taken at each of positions in the toe-heel direction. The radius of curvature is measured in each of the vertical cross sections.
The radius of curvature is determined at each of points present on the vertical cross-sectional contour line. The radius of curvature is determined by specifying three points on the vertical cross-sectional contour line: a point to be measured (hereinafter referred to as measurement point), a point located 0.5 mm apart from the measurement point toward one side, and a point located 0.5 mm apart from the measurement point toward the other side. The radius of a circle that passes through these three points is defined as the radius of curvature at the measurement point. “0.5 mm” for these points is a route distance measured along the vertical cross-sectional contour line. This “0.5 mm” is a sufficiently small distance for evaluating the radius of curvature at a measurement point. By specifying the two points located 0.5 mm apart from a measurement point, the radius of curvature at each point on a free-form curve can be determined without the need to solve the differential equation of a cross-sectional contour line.
The radius of curvature is determined for each point in the above-described manner. In the present disclosure, when the radius of curvature of a certain portion or a certain region is defined as greater than or equal to X mm and less than or equal to Y mm, this means that the radius of curvature at each of all points present in the portion or region is greater than or equal to X mm and less than or equal to Y mm.
In the vertical cross section of the present disclosure, points located on the head inner surface and points located on the head outer surface correspond to each other as follows. As to a certain point A located on the head outer surface, a line normal to the head outer surface at the point A is drawn. An intersection point between this normal line and the head inner surface is denoted by a point B, the point A and the point B correspond to each other. This can also be described such that the point A corresponds to the point B, or the point B corresponds to the point A.
As shown in
The golf club 2 is a driver (No. 1 wood). Preferably, the golf club 2 is a wood-type golf club or a hybrid-type golf club.
The shaft 6 is in a tubular form. The shaft 6 is hollow. The shaft 6 is made of a carbon fiber reinforced resin. From the viewpoint of reducing the weight, a carbon fiber reinforced resin is preferable as the material for the shaft 6. The shaft 6 is a so-called carbon shaft. Preferably, the shaft 6 is formed with a cured prepreg sheet. In the prepreg sheet, fibers are substantially oriented in one direction. Such a prepreg in which fibers are substantially oriented in one direction is also referred to as UD prepreg. “UD” is an abbreviation of “unidirectional”. A prepreg other than the UD prepreg may be used. For example, fibers contained in the prepreg sheet may be woven. The shaft 6 may include a metal wire. The material of the shaft 6 is not limited, and may be a metal, for example.
The grip 8 is a part that a golfer grips during a swing. Examples of the material of the grip 8 include rubber compositions and resin compositions. The rubber composition for the grip 8 may contain air bubbles.
As well shown in
As shown in
A peripheral edge of the striking face 10a can be defined as follows. As shown in
As shown in
Note that although score lines (grooves) are formed on the face outer surface 10a, the depiction of the score lines is omitted in the drawings of the present disclosure.
The hollow head 4 has a wall thickness. The wall thickness is the thickness between the inner surface of the head 4 and the outer surface of the head 4. For example, the wall thickness of the face portion 10 is the thickness between the striking face 10a and the face inner surface 10b. For example, the wall thickness of the sole portion 14 is the thickness between the sole outer surface 14a and the sole inner surface 14b. The wall thickness is measured along a line normal to the head outer surface. The direction of this normal line varies depending on the position on the head outer surface.
As well shown in
The face outer surface 10a is a three-dimensional curved surface that is convex toward the outside of the head 4. The face outer surface 10a includes a bulge and a roll.
In terms of constituent members, the head 4 includes a body member b1 and a face member f1. The body member b1 has a face opening b10. The face member f1 is disposed on the face opening b10. The face member f1 includes the entirety of the striking face 10a. The face member f1 closes the face opening b10. The face member f1 is welded to the face opening b10. The face member f1 includes a part of the crown portion 12. The face member f1 includes a part of the sole portion 14. The body member b1 includes a part of the crown portion 12. The body member b1 includes a part of the sole portion 14. The body member b1 includes the entirety of the hosel portion 16.
A two-dot chain line in
There is no limitation on the material of the body member b1. Examples of the material for the body member b1 include a metal and a fiber reinforced plastic. Examples of the metal include one or more metals selected from pure titanium, a titanium alloy, stainless steel, maraging steel, an aluminum alloy, a magnesium alloy, and a tungsten-nickel alloy. Examples of the fiber reinforced plastic include a carbon fiber reinforced plastic. The body member b1 may be integrally formed as a single-piece member. The body member b1 may be formed by joining a plurality of members to each other. For example, the body member b1 may be formed by joining a member made of a metal and a member made of a carbon fiber reinforced plastic to each other. In the present embodiment, the entirety of the body member b1 is formed of a metal. There is no limitation on the method for producing the body member b1. In the present embodiment, the body member b1 is produced by casting (lost-wax precision casting).
There is no limitation on the material of the face member f1. The face member f1 is preferably made of a metal. However, at least a peripheral portion 32 (detailed later) is formed of a material that can be welded to the opening b10 of the body member b1. From the viewpoint of strength, examples of a preferable material for the face member f1 include titanium alloys and maraging steel. There is no limitation on the method for producing the face member f1. From the viewpoint of strength, the face member f1 may be produced by pressing a plate material. A rolled material may be used as the plate material. Rolled materials have few defects and high strength. In addition, rolled materials are formed with high thickness accuracy. The wall thickness accuracy of the face portion 10 is improved by using a rolled material. The face member f1 may be produced by forging, for example. The face member f1 may be produced by casting. As described below, the peripheral portion of the face member f1 in the present disclosure has a short length. For this reason, the face member f1 can be easily formed by pressing or forging. In the present embodiment, the face member f1 is produced by pressing a rolled material. More specifically, the producing process of the face member f1 may include: a first step of machining a plate material (rolled material) to adjust wall thickness by CNC processing; a second step of pressing the plate material after being subjected to the first step; and a third step of shaping the peripheral portion by CNC processing using the resultant material after being subjected to the second step. In the second step, a curved surface (bulge and roll) of the face portion is formed, and a bent peripheral portion is also formed. However, when the peripheral portion has a short length as in the peripheral portion 32 of the face member f1, such a short peripheral portion may make it difficult to bend the peripheral portion, and may not be completely formed by pressing only. In this case, it is preferable to perform the third step of shaping the peripheral portion after the pressing step. The shaping step in the third step includes adjusting the length of the peripheral portion and/or adjusting the shape of the outer surface of the peripheral portion. A laser cutting may be used to adjust the length of the peripheral portion. CNC processing may be used to adjust the shape of the outer surface of the peripheral portion. When the shape of the outer surface of the peripheral portion is adjusted in the third step, the wall thickness of the peripheral portion in the first step can be set considering how much the outer surface is to be trimmed in the third step. It should be noted that “CNC” is an abbreviation for Computerized Numerical Control.
The face member f1 includes the face portion 10 forming the striking face 10a, and the peripheral portion 32 extending from the peripheral edge of the face portion 10 toward the back side. As shown in
The weld bead wb is formed in a welded portion. The weld bead wb is formed at a boundary position between the peripheral portion 32 and the body member b1. The weld bead wb is formed on the inner surface of the head 4. The weld bead wb juts from the head inner surface. In cross-sectional views of the present disclosure, the weld bead wb is schematically shown in a semicircular shape.
There is no limitation on the method of welding.
Examples of the method of welding include laser welding, arc welding, gas welding, and resistance welding. A filler material (such as a welding rod) may be used or may not be used. In the present embodiment, the welding is performed by laser welding. The weld bead wb may be formed of only a base material(s), may be formed of only the filler material, or may be formed of the base material(s) and the filler material. In the present embodiment, any filler material is not used, and the weld bead wb is formed of molten and solidified base materials (body member b1 and face member f1).
As shown in
The peripheral portion 32 includes a backward extending portion 38 that extends further backward than the face portion 10. The backward extending portion 38 is a portion that extends further backward than the straight line Tb. The backward extending portion 38 includes a sole-side backward extending portion 40 and a crown-side backward extending portion 42.
As shown in
As shown in
A double-pointed arrow L4 in
After the face member f1 and the body member b1 have been welded to each other, the boundary surface k2 might no longer be recognized. Although not shown in the drawings, the above-explained welding forms a welded portion that is formed by the materials of the members being molten and then solidified at and in the vicinity of the boundary surface k2. Although not shown the drawings, the welded portion shown in the vertical cross section has an irregular shape and a width.
The welding portion can make the boundary surface k2 unclear. When the boundary surface k2 is unclear, the end points P1 and P2 of the cross-sectional boundary line k3 might also be unclear. In this case, the points P1 and P2 can be determined in the following manner. As shown in
The point P1 is a center point of the weld bead wb, and is also referred to as a bead center point. The point P2 is also referred to as an outer surface boundary point.
In the vertical cross section, a point P4 and a point P6 are determined on the outer surface of the head 4 (see
In the vertical cross section, a point P7 is determined on the inner surface of the head 4 (see
In the vertical cross section, a point P9 is determined on the inner surface of the head 4 (see
As shown in
An inner surface 50b of the face-side weld vicinity portion 50 is a region that extends from the end point P3 to the point P7. An outer surface 50a of the face-side weld vicinity portion 50 is a region that extends from the point P4 to the peripheral edge Fe. An inner surface 52b of the body-side weld vicinity portion 52 is a region that extends from the end point P5 to the point P9. An outer surface 52a of the body-side weld vicinity portion 52 is a region that extends from the point P6 to the point P8. The outer surface 52a of the body-side weld vicinity portion 52 includes the outer surface boundary point P2.
A thick-walled joint portion 54 is formed between the face-side weld vicinity portion 50 and the body-side weld vicinity portion 52. The outer surface of the thick-walled joint portion 54 is a region that extends from the point P4 to the point P6. The inner surface of the thick-walled joint portion 54 is the surface of the weld bead wb. The thick-walled joint portion 54 connects the face-side weld vicinity portion 50 and the body-side weld vicinity portion 52.
A similar structure is also formed on the crown side. As shown in
As shown in
As shown in
It should be noted that the word “stepwise” used for wall thickness means that the wall thickness does not have to change in a stairs manner. That is, a configuration in which a portion having a constant wall thickness and a portion having a wall thickness continuously changing are connected to each other without a step is included in the concept of “stepwise”.
The wall thickness t1 includes a wall thickness t11 at the face-side end point P3 of the weld bead wb. The wall thickness t11 is the length of a line segment that connects the point P3 and the point P4. The wall thickness t11 is the wall thickness at the face-side end point P3 of the weld bead wb. The wall thickness t11 is the minimum wall thickness (has a minimum value) of the wall thickness t1. The wall thickness t2 includes a wall thickness t21 at the body-side end point P5 of the weld bead wb. The wall thickness t21 is the length of a line segment that connects the point P5 and the point P6. The wall thickness t21 is the wall thickness at the body-side end point P5 of the weld bead wb. The wall thickness t21 is the maximum wall thickness (has a maximum value) of the wall thickness t2.
The wall thickness t11 at the face-side end point P3 of the weld bead wb is greater than the wall thickness t21 at the body-side end point P5 of the weld bead wb.
The inner surface of the face-side weld vicinity portion 50 forms a smooth and continuous curved surface. The inner surface of the face-side weld vicinity portion 50 has a radius of curvature that falls in a predetermined range. The inner surface of the body-side weld vicinity portion 52 forms a smooth and continuous curved surface. The inner surface of the body-side weld vicinity portion 52 has a radius of curvature that falls in a predetermined range. The outer surface of the face-side weld vicinity portion 50 and the outer surface of the body-side weld vicinity portion 52 are made continuous with each other with the outer surface of the thick-walled joint portion 54 locating between the outer surface of the face-side weld vicinity portion 50 and the outer surface of the body-side weld vicinity portion 52. These outer surfaces have radii of curvature that fall in a predetermined range, and are smoothly continuous with each other.
As shown in
The head 4 exhibits the following advantageous effects.
The face member f1 is a cup-shaped face, and includes the peripheral portion 32. Accordingly, there is no welded portion in the face portion 10. In a welded portion, the presence of a weld bead increases wall thickness and enhances rigidity. Therefore, if such a welded portion is present in the face portion 10, the deflection of the face portion 10 can be suppressed due to the presence of the welded portion. In the face member f1, since a welded portion is not present in the face portion 10, the deflection of the entire face portion 10 is easily obtained.
In the head 4, the length L1 of the peripheral portion 32 is set to as short as less than or equal to 6 mm. For this reason, the welded portion between the face member f1 and the body member b1 is located in the vicinity of the boundary between the face portion 10 and the crown portion 12. Further, the welded portion between the face member f1 and the body member b1 is located in the vicinity of the boundary between the face portion 10 and the sole portion 14. The weld bead that juts from the head inner surface is formed on the welded portion. This configuration enhances the rigidity of the vicinity of the boundary portions (boundary portion between the face portion and the crown portion, and boundary portion between the face portion and the sole portion) of the face portion 10. Accordingly, the boundary between the face portion 10 and the crown portion 12 and the boundary between the face member f1 and the sole portion 14 are less likely to bend. As a result, the starting point of bending at impact with a golf ball (hereinafter, simply referred to as impact) can be shifted to the body side (back side).
The wall thickness t11 at the face-side end point P3 of the weld bead wb is greater than the wall thickness t21 at the body-side end point P5 of the weld bead wb. Accordingly, a portion closer to the face portion has an increased rigidity, and the starting point of bending at impact can be shifted to the body side.
By shifting the starting point of bending toward the body side, the deflection of the face portion 10 at impact extends to the body member b1 located apart from the face portion 10. This deformation of the body member b1 (the crown portion 12 and the sole portion 14) increases the amount of deflection of the entire face portion 10 as compared with a case where the boundary portion of the face portion 10 bends. As a result, the rebound performance is enhanced. This effect is also referred to as a body deflection effect.
From the viewpoint of the body deflection effect, the length L1 of the peripheral portion 32 is preferably less than or equal to 6.0 mm, more preferably less than or equal to 5.5 mm, and still more preferably less than or equal to 5.0 mm. When the weld bead wb is positioned too close to the face portion 10, the deformation of the face portion 10 is suppressed, and the boundary portion of the face portion 10 is more easily bent. From this viewpoint, the length L1 is preferably greater than or equal to 2.5 mm, more preferably greater than or equal to 2.7 mm, and still more preferably greater than or equal to 3.0 mm.
From the viewpoint of the body deflection effect on the sole side, the length L11 of the sole-side peripheral portion 34 is preferably less than or equal to 6.0 mm, more preferably less than or equal to 5.5 mm, and still more preferably less than or equal to 5.0 mm. When the weld bead wb is positioned too close to the face portion 10, the deformation of the face portion 10 is suppressed, and the boundary portion of the face portion 10 is more easily bent. From this viewpoint, the length L11 is preferably greater than or equal to 2.5 mm, more preferably greater than or equal to 2.7 mm, and still more preferably greater than or equal to 3.0 mm.
From the viewpoint of the body deflection effect on the crown side, the length L12 of the crown-side peripheral portion 36 is preferably less than or equal to 6.0 mm, more preferably less than or equal to 5.5 mm, and still more preferably less than or equal to 5.0 mm. When the weld bead wb is positioned too close to the face portion 10, the deformation of the face portion 10 is suppressed, and the boundary portion of the face portion 10 is more easily bent. From this viewpoint, the length L12 is preferably greater than or equal to 2.5 mm, more preferably greater than or equal to 2.7 mm, and still more preferably greater than or equal to 3.0 mm.
When the weld bead wb is positioned too close to the face portion 10, the deformation of the face portion 10 is suppressed, and the boundary portion of the face portion 10 is more easily bent. From this viewpoint, the length L1 of the peripheral portion 32 is preferably greater than the minimum thickness tmin, and is more preferably greater than the maximum thickness tmax.
On the sole side, when the weld bead wb is positioned too close to the face portion 10, the deformation of the sole-side part of the face portion 10 can be suppressed. From this viewpoint, the length L11 of the sole-side peripheral portion 34 is preferably greater than the minimum thickness tmin of the face portion 10, and is more preferably greater than the maximum thickness tmax of the face portion 10.
On the crown side, when the weld bead wb is positioned too close to the face portion 10, the deformation of the crown-side part of the face portion 10 can be suppressed. From this viewpoint, the length L12 of the crown-side peripheral portion 36 is preferably greater than the minimum thickness tmin, and is more preferably greater than the maximum thickness tmax.
From the viewpoint of the body deflection effect, the length L4 of the backward extending portion 38 is preferably less than or equal to 3.3 mm, more preferably less than or equal to 3.0 mm, and still more preferably less than or equal to 2.8 mm. When the weld bead wb is positioned too close to the face portion 10, the deformation of the face portion 10 is suppressed, and the boundary portion of the face portion 10 is more easily bent. From this viewpoint, the length L4 is preferably greater than or equal to 0.5 mm, more preferably greater than or equal to 0.7 mm, and still more preferably greater than or equal to 0.9 mm.
From the viewpoint of the body deflection effect on the sole side, the length L41 of the sole-side backward extending portion 40 is preferably less than or equal to 3.3 mm, more preferably less than or equal to 3.0 mm, and still more preferably less than or equal to 2.8 mm. When the weld bead wb is positioned too close to the face portion 10, the deformation of the face portion 10 is suppressed, and the boundary portion of the face portion 10 is more easily bent. From this viewpoint, the length L41 is preferably greater than or equal to 0.5 mm, more preferably greater than or equal to 0.7 mm, and still more preferably greater than or equal to 0.9 mm.
From the viewpoint of the body deflection effect on the crown side, the length L42 of the crown-side backward extending portion 42 is preferably less than or equal to 3.3 mm, more preferably less than or equal to 3.0 mm, and still more preferably less than or equal to 2.8 mm. When the weld bead wb is positioned too close to the face portion 10, the deformation of the face portion 10 is suppressed, and the boundary portion of the face portion 10 is more easily bent. From this viewpoint, the length L42 is preferably greater than or equal to 0.5 mm, more preferably greater than or equal to 0.7 mm, and still more preferably greater than or equal to 0.9 mm.
From the viewpoint of the body deflection effect, the length L4 of the backward extending portion 38 is preferably smaller than the maximum thickness tmax, and more preferably smaller than the minimum thickness tmin. When the weld bead wb is positioned too close to the face portion 10, the deformation of the face portion 10 is suppressed, and the boundary portion of the face portion 10 is more easily bent. From this viewpoint, it is preferable that the backward extending portion 38 is present.
From the viewpoint of the body deflection effect on the sole side, the length L41 of the sole-side backward extending portion 40 is preferably smaller than the maximum thickness tmax, and more preferably smaller than the minimum thickness tmin. When the weld bead wb is positioned too close to the face portion 10, the deformation of the face portion 10 is suppressed, and the boundary portion of the face portion 10 is more easily bent. From this viewpoint, it is preferable that the sole-side backward extending portion 40 is present.
From the viewpoint of the body deflection effect on the crown side, the length L42 of the crown-side backward extending portion 42 is preferably smaller than the maximum thickness tmax, and more preferably smaller than the minimum thickness tmin. When the weld bead wb is positioned too close to the face portion 10, the deformation of the face portion 10 is suppressed, and the boundary portion of the face portion 10 is more easily bent. From this viewpoint, it is preferable that the crown-side backward extending portion 42 is present.
L4/L1 is a ratio of the length L4 of the backward extending portion 38 to the length L1 of the peripheral portion 32. From the viewpoint of the body deflection effect, L4/L1 is preferably less than or equal to 0.55, more preferably less than or equal to 0.5, and still more preferably less than or equal to 0.45. When the weld bead wb is positioned too close to the face portion 10, the deformation of the face portion 10 is suppressed, and the boundary portion of the face portion 10 is more easily bent. From this viewpoint, L4/L1 is preferably greater than or equal to 0.08, more preferably greater than or equal to 0.1, and still more preferably greater than or equal to 0.15.
L41/L11 is a ratio of the length L41 of the sole-side backward extending portion 40 to the length L11 of the sole-side peripheral portion 34. From the viewpoint of the body deflection effect on the sole side, L41/L11 is preferably less than or equal to 0.55, more preferably less than or equal to 0.5, and still more preferably less than or equal to 0.45. When the weld bead wb is positioned too close to the face portion 10, the deformation of the face portion 10 is suppressed, and the boundary portion of the face portion 10 is more easily bent. From this viewpoint, L41/L11 is preferably greater than or equal to 0.08, more preferably greater than or equal to 0.1, and still more preferably greater than or equal to 0.15.
L42/L12 is a ratio of the length L42 of the crown-side backward extending portion 42 to the length L12 of the crown-side peripheral portion 36. From the viewpoint of body deflection effect on the crown side, L42/L12 is preferably less than or equal to 0.55, more preferably less than or equal to 0.5, and still more preferably less than or equal to 0.45. When the weld bead wb is positioned too close to the face portion 10, the deformation of the face portion 10 is suppressed, and the boundary portion of the face portion 10 is more easily bent. From this viewpoint, L42/L12 is preferably greater than or equal to 0.08, more preferably greater than or equal to 0.1, and still more preferably greater than or equal to 0.15.
The wall thickness t1 of the face-side weld vicinity portion 50 decreases as its proximity to the face portion 10 decreases (see
From the viewpoint of suppressing the bending of the face-side weld vicinity portion 50 and shifting the starting point of bending at impact toward the back side, the wall thickness t1 is preferably greater than or equal to 1.2 mm, more preferably greater than or equal to 1.3 mm, and still more preferably greater than or equal to 1.4 mm. From the viewpoint of providing an appropriate distribution of wall thickness from the face portion 10 to the body member b1, and shifting the starting point of bending toward the back side, the wall thickness t1 is preferably less than or equal to 2.0 mm, more preferably less than or equal to 1.8 mm, and still more preferably less than or equal to 1.6 mm. The wall thickness t1 is preferably smaller than the maximum thickness tmax of the face portion 10, and is more preferably smaller than the minimum thickness tmin of the face portion 10.
The wall thickness t2 of the body-side weld vicinity portion 52 decreases as its proximity to the face portion 10 decreases (see
From the viewpoint of suppressing the bending of the body-side weld vicinity portion 52 and shifting the starting point of bending at impact toward the back side, the wall thickness t2 is preferably greater than or equal to 0.8 mm, more preferably greater than or equal to 0.9 mm, and still more preferably greater than or equal to 1.0 mm. From the viewpoint of providing an appropriate distribution of wall thickness from the face portion 10 to the body member b1, and shifting the starting point of bending toward the back side, the wall thickness t2 is preferably less than or equal to 1.8 mm, more preferably less than or equal to 1.6 mm, and still more preferably less than or equal to 1.4 mm. The wall thickness t2 is preferably smaller than the maximum thickness tmax of the face portion 10, and is more preferably smaller than the minimum thickness tmin of the face portion 10. The wall thickness t2 is preferably smaller than the wall thickness t11 at the face-side end point of the weld bead wb.
By increasing the radius of curvature of the inner surface 50b of the face-side weld vicinity portion 50, the bending deformation of the face-side weld vicinity portion 50 is suppressed. For this reason, the starting point of bending at impact can be more effectively shifted toward the body side (back side) (see
By increasing the radius of curvature of the outer surface 50a of the face-side weld vicinity portion 50, the bending deformation of the face-side weld vicinity portion 50 is suppressed. For this reason, the starting point of bending at impact can be more effectively shifted toward the body side (back side) (see
By increasing the radius of curvature of the inner surface 52b of the body-side weld vicinity portion 52, the starting point of bending at impact can be more effectively shifted to the body side (back side) (see
By increasing the radius of curvature of the outer surface 52a of the body-side weld vicinity portion 52, the starting point of bending at impact can be more effectively shifted to the body side (back side) (see
As described above, the head 4 is placed on the ground plane HP when the head 4 is in the reference state. In the vertical cross section passing through the face center Fc, the outer surface boundary point P2 is not in contact with the ground plane HP (see
As described above, the vertical cross section is set at each position in the toe-heel direction. By extending the above-described shapes in the toe-heel direction, the body deflection effect is enhanced. All the above-described structures are preferably satisfied in the vertical cross section passing through the face center Fc, more preferably satisfied in all vertical cross sections taken at positions falling in a range between a point located 10 mm apart from the face center Fc toward the toe side and a point located 10 mm apart from the face center Fc toward the heel side, still more preferably satisfied in all vertical cross sections taken at positions falling in a range between a point located 15 mm apart from the face center Fc toward the toe side and a point located 15 mm apart from the face center Fc toward the heel side, and yet still more preferably satisfied in all vertical cross sections taken at positions falling in a range between a point located 20 mm apart from the face center Fc toward the toe side and a point located 20 mm apart from the face center Fc toward the heel side.
From the viewpoint of transmitting a force generated on the face portion 10 by impact against a golf ball to the crown portion 12 and deforming the crown portion 12, an angle formed between the face portion 10 and the crown portion 12 is preferably close to the right angle. From the viewpoint of transmitting the force generated on the face portion 10 by impact against a golf ball to the sole portion 14 and deforming the sole portion 14, an angle formed between the face portion 10 and the sole portion 14 is preferably close to the right angle. From these viewpoints, the head preferably has a small loft angle. The real loft angle is preferably less than or equal to 16 degrees, more preferably less than or equal to 15 degrees, and still more preferably less than or equal to 14 degrees. From the viewpoint of an appropriate launch angle of a hit ball, the real loft angle is preferably greater than or equal to 7 degrees, more preferably greater than or equal to 7.5 degrees, and still more preferably greater than or equal to 8 degrees.
Regarding the above-described embodiments, the following clauses are disclosed.
A golf club head being hollow and having a head outer surface and a head inner surface, the golf club head including:
a body member that has an opening; and
a face member that includes a striking face and closes the opening, wherein
the face member includes a face portion that forms the striking face, and a peripheral portion that extends from a peripheral edge of the face portion toward a back side,
the peripheral portion of the face member is welded to the body member,
a weld bead that juts from the head inner surface is formed at a boundary position between the peripheral portion and the body member,
a wall thickness at a face-side end point of the weld bead is greater than a wall thickness at a body-side end point of the weld bead, and
the peripheral portion has a length of less than or equal to 6 mm.
The golf club head according to clause 1, wherein the peripheral portion includes a backward extending portion that extends further backward than the face portion.
The golf club head according to clause 1 or 2, wherein
when a portion that extends from the peripheral edge of the face portion to the weld bead is defined as a face-side weld vicinity portion, and
when a portion that extends from the weld bead to a position located 6 mm apart from a center point of the weld bead toward a body side is defined as a body-side weld vicinity portion, then
a wall thickness of the face-side weld vicinity portion decreases as its proximity to the face portion decreases, and
a wall thickness of the body-side weld vicinity portion decreases as its proximity to the face portion decreases.
The golf club head according to clause 3, wherein
a radius of curvature of an inner surface of the face-side weld vicinity portion is greater than or equal to 7 mm, and
a radius of curvature of an outer surface of the face-side weld vicinity portion is greater than or equal to 7 mm.
The golf club head according to any one of clauses 1 to 4, wherein the length of the peripheral portion is greater than a minimum thickness of the face portion.
The golf club head according to any one of clauses 1 to 5, wherein the peripheral portion is a sole-side peripheral portion that is formed in a sole-side part of the face member.
The above descriptions are merely illustrative and various modifications can be made without departing from the principles of the present disclosure.
The terminology used in the description of the various described embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting. The use of the terms “a”, “an”, “the”, and similar referents in the context of throughout this disclosure (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. As used throughout this disclosure, the word “may” is used in a permissive sense (i.e., meaning “having the potential to”), rather than the mandatory sense (i.e., meaning “must”). Similarly, as used throughout this disclosure, the terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted.
Number | Date | Country | Kind |
---|---|---|---|
2021-017094 | Feb 2021 | JP | national |