GOLF CLUB HEAD

Abstract

A golf club head including a cup face is provided. The cup face includes a face portion and a rising portion extending from a peripheral edge of the face portion on a rear surface side of the face portion. The peripheral edge of the face portion includes a top line on a top side and a sole line on a sole side. The face portion includes a central region and peripheral regions. The central region includes a face center, extends from the sole line to the top line while being inclined from the sole side to the top side along a direction from the heel side toward the toe side, and does not reach the toe-side edge point. The peripheral regions are thinner than the central region and surround the central region on the toe side and the heel side.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims a priority to Japanese Patent Application No. 2014-134290 filed on Jun. 30, 2014, which is hereby incorporated by reference in its entirety.

FIELD OF INVENTION

The present invention relates to a golf club head that includes a cup face.

BACKGROUND

Conventionally, golf club heads that include a cup face are known (see JP 2010-530783A). Also, conventionally, various innovations have been made with respect to the design of the thickness of the faces of golf club heads from the viewpoint of strength, the viewpoint of extending the flight-distance, and the like.

According to examinations carried out by the inventors of the present invention, if an area that is thin and has a high coefficient of restitution (hereinafter, referred to as a high restitution area) is increased in size, there is a risk of impairing the hitting sensation of the golf club. Specifically, when the ball is seized by the thin high restitution area, the hitting sensation becomes lighter, and experienced players in particular dislike this light sensation. On the other hand, improving the hitting sensation by blindly increasing the thickness faces the problems of a decrease in the size of the high restitution area and an inability to extend the flight-distance.

SUMMARY of INVENTION

An object of the present invention is to provide a golf club head that has a favorable hitting sensation, while also extending the flight-distance.

A golf club head according to a first aspect of the present invention is a golf club head that includes a cup face. The cup face includes a face portion for hitting a ball, and a rising portion extending from a peripheral edge of the face portion on a rear surface side of the face portion. The peripheral edge of the face portion includes a top line on a top side extending from a toe-side edge point to a heel-side edge point, and a sole line on a sole side extending from the toe-side edge point to the heel-side edge point. The toe-side edge point is the point that is farthest on a toe side on the peripheral edge of the face portion. The heel-side edge point is the point that is farthest on a heel side on the peripheral edge of the face portion. The face portion includes a central region and peripheral regions. The central region includes a face center, extends from the sole line to the top line while being inclined from the sole side to the top side along a direction from the heel side toward the toe side, and does not reach the toe-side edge point. The peripheral regions are thinner than the central region and surround the central region on the toe side and the heel side.

A golf club head according to a second aspect of the present invention is the golf club head according to the first aspect, wherein the central region has a thick portion including the face center, and a transition portion located between the thick portion and the peripheral regions. The transition portion is thinner than the thick portion and thicker than the peripheral regions.

A golf club head according to a third aspect of the present invention is the golf club head according to the second aspect, wherein the transition portion gradually decreases in thickness in a direction from the thick portion toward the peripheral regions.

A golf club head according to a fourth aspect of the present invention is the golf club head according to the second aspect or the third aspect, wherein the transition portion surrounds an entire circumference of the thick portion.

A golf club head according to a fifth aspect of the present invention is the golf club head according to any of the second to fourth aspects, wherein the transition portion is continuous with the top line and the sole line.

A golf club head according to a sixth aspect of the present invention is the golf club head according to any of the first to fifth aspects, wherein the central region is I-shaped. Note that “I-shape” herein means a shape like a capital “I” character. In other words, “I-shape” may mean a shape extending along a single straight line, or it may be a longitudinal shape.

A golf club head according to a seventh aspect of the present invention is the golf club head according to the sixth aspect, wherein the central region is I-shaped having a bulge on at least one side of the toe side and the heel side.

A golf club head according to an eighth aspect of the present invention is the golf club head according to any of the second to fifth aspects, wherein the thick portion is I-shaped.

A golf club head according to a ninth aspect of the present invention is the golf club head according to the eighth aspect, wherein the thick portion is I-shaped having a bulge on at least one side of the toe side and the heel side.

A golf club head according to a tenth aspect of the present invention is the golf club head according to any of the first to ninth aspects, wherein letting θ1 be an angle formed by a toe-heel direction and a line segment passing through a geometrical center of the central region or the thick portion, overlapping the central region, and having a maximum length, 5°≦θ1<90°.

A golf club head according to an eleventh aspect of the present invention is the golf club head according to the tenth aspect, wherein letting θ1 be an angle formed by a toe-heel direction and a line segment passing through a geometrical center of the central region or the thick portion, overlapping the central region, and having a maximum length, 30°≦θ1≦50°.

Generally, on the face surface, hit points are distributed along a straight line that passes through the face center and is inclined from the sole side to the top side along the direction from the heel side toward the toe side. More specifically, the region in which the hit points are distributed extends relatively over the entire face surface in the top-sole direction, and is concentrated relatively in the central portion of the face surface in the toe-heel direction.

With the golf club head according to the first aspect, the region conforming to this distribution of hit points (central region) is designed to be thicker than the peripheral regions. Impairment of the hitting sensation is therefore prevented. Also, since a cup face construction is employed, a sufficient flight-distance can be maintained.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a golf club head according to an embodiment in a reference state;

FIG. 2 is a plan view of the golf club head in the reference state;

FIG. 3 is a cross-sectional view taken along line A-A in FIG. 2;

FIG. 4 is a rear view of the cup face in the reference state;

FIG. 5 is a rear view of a cup face according to a variation in the reference state;

FIG. 6 is a rear view of a cup face according to another variation in the reference state; and

FIG. 7 is a rear view of a cup face according to yet another variation in the reference state.

FIG. 8 is a rear view of a cup face according to yet another variation in the reference state.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A golf club head according to an embodiment of the present invention will be described below with reference to the drawings.

1. Overview of Golf Club Head

FIG. 1 is a perspective view of a golf club head (hereinafter sometimes simply referred to as the “head”) 100 of the present embodiment in a reference state, and FIG. 2 is a plan view of the head 100 in the reference state. Note that the reference state of the golf club head will be described later. The head 100 is a hollow structure and has wall surfaces formed by a cup face 1, a crown portion 2, a sole portion 3, a side portion 4, and a hosel portion 5.

The cup face 1 constitutes a front portion of the head 100 that serves as the surface for hitting a ball. The crown portion 2 is adjacent to the cup face 1 and constitutes the upper surface of the head 100. The sole portion 3 constitutes the bottom surface of the head 100, and is adjacent to the cup face 1 and the side portion 4. Also, the side portion 4 is the portion between the crown portion 2 and the sole portion 3, and extends from the toe side of the cup face 1, across the back side of the head 100, to the heel side of the cup face 1. Furthermore, the hosel portion 5 is the portion provided adjacent to the heel side of the crown portion 2, and has an insertion hole 51 for the insertion of the shaft (not shown) of the golf club. A central axis Z of the insertion hole 51 conforms to the axis of the shaft. The head 100 described here is a wood-type head such as a fairway wood or a driver (#1), but there is no limitation on the type, and it may be of the so-called utility-type, hybrid-type, or the like.

The following describes the aforementioned reference state. As shown in FIGS. 1 and 2, the reference state is defined as a state in which the central axis Z is in a plane P (hereinafter, the reference vertical plane P) that is perpendicular to a horizontal plane H (see FIG. 3), and furthermore the head is placed on the horizontal plane H at a predetermined lie angle and real loft angle. Also, as shown in FIG. 2, the direction of the line of intersection of the reference vertical plane P and the horizontal plane H will be referred to as the toe-heel direction, and the direction that is perpendicular to the toe-heel direction and parallel to the horizontal plane H will be referred to as the face-back direction. Also, the direction perpendicular to the horizontal plane H will be referred to as the sole-top direction.

The head 100 can be formed from a titanium alloy having a specific gravity of approximately 4.4 to 5.0 (e.g., Ti-6Al-4V), for example. Besides a titanium alloy, the head can be formed from one or two or more materials selected from among stainless steel, maraging steel, an aluminum alloy, a magnesium alloy, an amorphous alloy, and the like. Also, there is no limitation to a metal material, and the head can also be formed using a fiber-reinforced plastic or the like.

The head 100 of the present embodiment is constituted by assembling the cup face 1 with a head body 6 that has the crown portion 2, the sole portion 3, the side portion 4, and the hosel portion 5. The head body 6 and the cup face 1 are joined by welding (plasma welding, laser welding, brazing, etc.), for example. The head body 6 has an opening surrounding by the crown portion 2, the sole portion 3, and the side portion 4, and the cup face 1 is attached so as to block this opening. The head body 6 can also be an assembly of multiple parts, and can also be formed as a single body. The head body 6 and the cup face 1 can be produced using various methods. For example, the head body 6 can be manufactured by casting using a known lost-wax precision casting method or the like. Also, the cup face 1 can be manufactured using a forging method, flat plate press machining, or the like. Details of the structure of the cup face 1 will be described below.

2. Structure of Cup Face

The following describes the cup face 1 with reference to FIGS. 3 and 4 as well. FIG. 3 is a cross-sectional view taken along line A-A in FIG. 2. FIG. 4 is a view of the cup face 1 in the reference state, as viewed from the rear surface side. As shown in FIG. 3, the cup face 1 is shaped as a cup that has a flat plate-shaped face portion 1 for hitting a ball and a rising portion 12 that extends from the peripheral edge of the face portion 11 on the rear surface side of the face portion 11 (toward a rear side of the golf club head 100).

In this way, compared to a face not having a rising portion, with the cup face 1 having the rising portion 12, the surface area of flexing area is larger by an amount corresponding to the rising portion 12, and thus the cup face 1 flexes more easily and has a higher coefficient of restitution. In other words, this cup face 1 contributes to an increase in flight-distance.

The front surface (hereinafter, called the face surface) side of the face portion 11 that serves as the ball hitting face is formed so as to be flat. On the other hand, unevenness is formed on the rear surface side of the face portion 11. In other words, the face portion 11 is constituted by multiple regions having different thicknesses. More specifically, a thick central region 20 is formed in the face portion 11, and thin peripheral regions 30a and 30b are formed so as to surround the central region 20. The peripheral region 30a is adjacent to the heel side of the central region 20. The peripheral region 30b is adjacent to the toe side of the central region 20. Also, the central region 20 has a thick portion 21 that is the thickest and located inward, and a transition portion 22 that surrounds the thick portion 21, and is thicker than the peripheral regions 30a and 30b but thinner than the thick portion 21. In the present embodiment, the transition portion 22 is constituted so as to gradually decrease in thickness from the thick portion 21 toward the peripheral regions 30a and 30b, and this change in thickness is continuous. However, the thicknesses of the transition portion 22 may be constant, and even in the case of changing, the thicknesses may change in a non-continuous manner, such as in a stepwise manner.

In the present embodiment, a thickness w1 of the thick portion 21 is roughly constant and, for example, can be set to 2.0 mm≦w1≦4.5 mm or more preferably 3.0 mm≦w1≦4.0 mm. Also, in the present embodiment, a thickness w2 of the peripheral regions 30a and 30b is roughly constant and, for example, can be set to 1.5 mm≦w2≦3.0 mm or more preferably 1.8 mm≦w2≦2.6 mm. Accordingly, the central region 20 (particularly the thick portion 21) is a low restitution area having a relatively low coefficient of restitution, and the peripheral regions 30a and 30b are high restitution areas having a relatively high coefficient of restitution.

Hereinafter, for the sake of convenience in the description, assuming that the head 100 is placed in the reference state, a point P1 farthest on the toe side on the peripheral edge of the face portion 11 will be referred to as the toe-side edge point, and a point P2 farthest on the heel side on the peripheral edge of the face portion 11 will be referred to as the heel-side edge point (see FIG. 4). Also, on the peripheral edge of the face portion 11, the top-side line extending from the toe-side edge point P1 to the heel-side edge point P2 will be referred to as a top line L1, and a sole-side line extending from the toe-side edge point P1 to the heel-side edge point P2 will be referred to as a sole line L2.

As shown in FIG. 4, the thick portion 21 includes a face center Pc and a sweet spot located in the vicinity thereof, is roughly elliptical overall, and extends in an “I” shape while being inclined from the sole side toward the top side along the direction from the heel side toward the toe side. Note that the sweet spot is the intersection of the face portion 11 and the line that passes through the center of gravity of the golf club head 100 and is perpendicular to the face portion 11. Also, the thick portion 21 extends relatively over the entire face portion 11 in the top-sole direction, but is concentrated relatively in the central portion of the face portion 11 in the toe-heel direction, and does not reach the toe-side edge point P1. Note that in the present embodiment, the face center Pc is specified as follows. Specifically, first, on the face surface, a maximum width Wx in the toe-heel direction is determined, and a central position Px in the toe-heel direction at the maximum width Wx is determined. Then, at the position Px, a central point Py in the up-down direction of the face surface is determined, and this point Py is defined as a face center Pc.

Meanwhile, the transition portion 22 completely surrounds the thick portion 21, and has a roughly uniform width along the circumferential direction, with the exception of portions that surround the top-side and sole-side end portions of the thick portion 21. Note that in the present embodiment, the portions of the transition portion 22 that surround the top-side and sole-side end portions of the thick portion 21 are narrower than the portions that surround the toe-side and heel-side end portions of the thick portion 21. As a result, the central region 20 made up of the thick portion 21 and the transition portion 22 is also roughly elliptical overall, and extends in an “I” shape while being inclined from the sole side toward the top side along the direction from the heel side toward the toe side. Also, the transition portion 22 reaches the top line L1 and the sole line L2. In other words, the I-shaped central region 20 intersects the top line L1 and the sole line L2 at one location each. The central region 20 extends over the entire face portion 11 in the top-sole direction, but is concentrated relatively in the central portion of the face portion 11 in the toe-heel direction, and does not reach the toe-side edge point P1.

If the thickness of the face portion 11 rapidly decreases in the vicinity of the boundary line between the face portion 11 and the rising portion 12, stress becomes concentrated in this thin portion, and there is a risk of having an effect on the durability of the face portion 11. However, in the present embodiment, the transition portion 22 is continuous with the top line L1 and the sole line L2 as described above. In other words, the thick portion 21 does not suddenly end in the vicinity of the rising portion 12, nor does the thickness of the face portion 11 rapidly decrease. The strength of the cup face 1 is therefore ensured.

Let L3 be a line segment that passes through a center Pw (geometrical center) of the thick portion 21, overlaps the central region 20, and has a maximum length. An angle θ1 formed by the line segment L3 and the toe-heel direction can be set to 5°≦θ1<90° or more preferably 30°≦θ1≦50°, for example. Note that in order to simplify the description in the present embodiment, the center Pw of the thick portion 21 matches the center (geometrical center) of the central region 20, and matches the face center Pc as well. Note that the aforementioned matching does not necessarily indicate complete matching, and there are cases where, for example, the center Pw of the thick portion 21 and the face center Pc match with a narrow range of deviation up to approximately 5 mm.

Let P3 and P4 be points of intersection between the line segment L3 and the outline of the thick portion 21 (the point P3 being on the top side and the point P4 being on the sole side). The relationship between a length t1 of the line segment L3 and a length t2 between the points P3 and P4 can be set to 0.2≦t2/t1≦1 or more preferably 0.5≦t2/t1≦0.95, for example. Also, let L4 be a straight line that passes through the center Pw of the thick portion 21 and extends in the toe-heel direction, and P5 and P6 be points of intersection between the straight line L4 and the outline of the thick portion 21 (the point P5 being on the toe side and the point P6 being on the heel side). A distance t3 between the points Pw and P5 can be set to 5 mm≦t3≦20 mm or more preferably 7 mm≦t3≦15 mm, for example. The same follows for a distance t4 between the points Pw and P6, and t3 and t4 are roughly the same. Also, let P7 and P8 be points of intersection between the straight line L4 and the outer outlines of the transition portion 22 (the point P7 being on the toe side and the point P8 being on the heel side). A distance t5 between the points Pw and P7 can be set to 15 mm≦t5≦35 mm or more preferably 20 mm≦t5≦25 mm, for example. The same follows for a distance t6 between the points Pw and P8, and t5 and t6 are roughly the same.

Generally, on the face surface, hit points are distributed along a straight line that passes through the face center and is inclined from the sole side to the top side along the direction from the heel side toward the toe side. More specifically, the region in which the hit points are distributed extends over relatively the entire face surface in the top-sole direction, and is concentrated relatively in the central portion of the face surface in the toe-heel direction. Accordingly, it can be said that the above-described thick central region 20 (particularly the thick portion 21) extends in conformity with the distribution of hit points in the face portion 11. As a result, with the cup face 1, it is possible to obtain a comfortable hitting sensation having a sense of weight, and this hitting sensation is favored by experienced golf players in particular.

3. Features

With the golf club head 100, the region conforming to the distribution of hit points (the central region 20, and particularly the thick portion 21) is designed to be thicker than the peripheral regions 30a and 30b. Accordingly, it is possible to obtain a comfortable hitting sensation having a sense of weight, which is favored by experienced golf players in particular. Also, since a cup face construction is employed in the golf club head 100, a sufficient flight-distance can be maintained.

4. Variations

Although an embodiment of the present invention has been described above, the present invention is not limited to this embodiment, and various modifications can be made without departing from the gist of the invention. The following are examples of modifications that can be made. Any combination of the features of the following variations can be used as appropriate.

4-1

Although the transition portion 22 is provided in the periphery of the thick portion 21 in the above embodiment, a configuration is possible in which the transition portion 22 is omitted, and the thin peripheral regions 30a and 30b are provided directly in the periphery of the thick portion 21. Note that in this case, it is preferable that the thick portion 21 extends from the top line L1 to the sole line L2 from the viewpoint of ensuring the strength of the cup face 1. Also, a configuration is possible in which the thick portion 21 extends to at least one of the top line L1 and the sole line L2 while keeping the transition portion 22 adjacent on the toe side and the heel side of the thick portion 21.

4-2

The shapes of the thick portion 21 and the transition portion 22 are not limited to the shapes described above, and can be changed as appropriate. For example, the thick portion 21 (the central region 20) of the above embodiment has almost no change in width along the line segment L3 as shown in FIG. 4, but a configuration is possible in which, as shown in FIG. 5, the thick portion 21 (the central region 20) is I-shaped so as to have a wider width in the central region along the line segment L3 and decrease in width as it approaches the top side and the sole side. In the example in FIG. 5, compared with the example in FIG. 4, the thick portion 21 (the central region 20) expands outward on both the toe side and the heel side in the vicinity of the center Pw. Also, as shown in FIG. 6, the thick portion 21 (the central region 20) can be I-shaped having a bulge on at least one side of the toe side and the heel side in the center (can also be called a φ shape, if the bulde on each side of the toe side and the heel side is provided). As shown in FIG. 7, the bulge on at least one side of the toe side and the heel side may be formed in a somewhat off center point. In this case, it is possible to hit the ball with the thick portion 21 or the transition portion 22 and maintain a favorable hitting sensation not only during a normal shot in which the ball is seized at the face center Pc, but also during a shot in which the ball is seized at a location away from the face center in order to change the ball trajectory.

Also, although the center Pw of the thick portion 21 (the center of the central region 20) and the face center Pc match each other in the above embodiment, in the case where the center Pw is shifted toward the toe side relative to the face center Pc, that is to say in the case where the thick portion 21 (the central region 20) is shifted toward the toe side, the thick portion 21 (the central region 20) can be shaped as shown in FIG. 8. Specifically, in the example in FIG. 8, compared with the example in FIG. 4, the thick portion 21 (the central region 20) expands outward on only the heel side in the vicinity of the center Pw. Conversely, in the case where the center Pw is shifted toward the heel side relative to the face center Pc, that is to say in the case where the thick portion 21 (the central region 20) is shifted toward the heel side, the thick portion 21 (the central region 20) may expand outward on only the toe side in the vicinity of the center Pw.

REFERENCE SIGNS LIST

1 Cup face

11 Face portion

12 Rising portion

20 Central region

21 Thick portion

22 Transition portion

30a, 30b Peripheral region

100 Golf club head

L1 Top line

L2 Sole line

P1 Toe-side edge point

P2 Heel-side edge point

Pc Face center

Claims

1. A golf club head comprising a cup face,

the cup face including a face portion for hitting a ball, and a rising portion extending from a peripheral edge of the face portion on a rear surface side of the face portion,

the peripheral edge of the face portion including a top line on a top side extending from a toe-side edge point that is a point farthest on a toe side to a heel-side edge point that is a point farthest on a heel side, and a sole line on a sole side extending from the toe-side edge point to the heel-side edge point, and

the face portion including a central region including a face center, the central region extending from the sole line to the top line while being inclined from the sole side to the top side along a direction from the heel side toward the toe side, and the central region not reaching the toe-side edge point, and peripheral regions thinner than the central region and surrounding the central region on the toe side and the heel side.

2. The golf club head according to claim 1,

wherein the central region has a thick portion including the face center, and a transition portion located between the thick portion and the peripheral regions, the transition portion being thinner than the thick portion and thicker than the peripheral regions.

3. The golf club head according to claim 2, wherein the transition portion gradually decreases in thickness in a direction from the thick portion toward the peripheral regions.

4. The golf club head according to claim 3, wherein the transition portion surrounds an entire circumference of the thick portion.

5. The golf club head according to claim 4,

wherein letting θ1 be an angle formed by a toe-heel direction and a line segment passing through a geometrical center of the central region or the thick portion, overlapping the central region, and having a maximum length,

30°≦θ1≦50°.

6. The golf club head according to claim 4, wherein the thick portion is I-shaped.

7. The golf club head according to claim 6, wherein the central region is I-shaped.

8. The golf club head according to claim 2, wherein the transition portion surrounds an entire circumference of the thick portion.

9. The golf club head according to claim 8, wherein the thick portion is I-shaped.

10. The golf club head according to claim 2, wherein the transition portion is continuous with the top line and the sole line.

11. The golf club head according to claim 2, wherein the thick portion is I-shaped.

12. The golf club head according to claim 11, wherein the thick portion is I-shaped having a bulge on at least one side of the toe side and the heel side.

13. The golf club head according to claim 1, wherein the central region is I-shaped.

14. The golf club head according to claim 13, wherein the central region is I-shaped having a bulge on at least one side of the toe side and the heel side.

15. The golf club head according to claim 1,

wherein letting θ1 be an angle formed by a toe-heel direction and a line segment passing through a geometrical center of the central region or the thick portion, overlapping the central region, and having a maximum length,

5°≦θ1≦90°.

16. The golf club head according to claim 15,

wherein letting θ1 be an angle formed by a toe-heel direction and a line segment passing through a geometrical center of the central region or the thick portion, overlapping the central region, and having a maximum length,

30°≦θ1≦50°.