GOLF CLUB HEAD

Abstract

This golf club head includes a face portion, a crown portion and a sole portion, the crown portion including a first region extending along at least part of the face portion, a second region arranged further on a back side than the first region, and a step region extending in the toe-heel direction between the first and the second regions and extending downward toward the second region from the first region side, the first region being formed to at least extend from a position Ph that is 20 mm on a heel side to a position Pt that is 25 mm on a toe side, based on a face center, and a width Dh of the first region in a face-back direction at the position Ph and a width Dt of the first region in the face-back direction at the position Pt satisfying 1<(Dt/Dh)≤1.35.

Description

TECHNICAL FIELD

The present invention relates to a golf club head.

BACKGROUND ART

In recent years, golf club heads have been proposed in which a raised portion extending in the toe-heel direction is provided on the crown portion and a sloped surface is formed as a step between the raised portion and the portion rearward thereof (e.g., JP 2015-29628A). A golfer, by sighting this step, is better able to determine the direction of the shot at address.

JP 2015-29628A is an example of related art.

SUMMARY OF THE INVENTION

Incidentally, golfers, in order to better catch the ball or to prevent slicing, sometimes intentionally grip the club at address with the face rotated in a direction that closes the face (e.g., in a direction whereby the face is turned to the left of the target direction in the case of a right-handed club). Note that “better catching the ball” refers, for example, to ensuring that the ball is not launched to the right of the intended launch direction (left-right direction), in the case of a right-handed golfer. However, golfers normally address the ball such that the orientation of the face (e.g., orientation of the upper end edge of the face in the case of a wood-type golf club) is perpendicular to a target line (target direction) as a reference at address. Thus, in the case where the face is closed at address as described above, the orientation of the face is not perpendicular to the target direction, possibly giving rise to a sense of incongruity.

In particular, with a club such as described in JP 2015-29628A, there is a problem in that since a step is formed on the crown portion, the orientation of the face becomes easier to sight, thereby exacerbating the sense of incongruity. The present disclosure was made in order to solve this problem, and an object thereof is to provide a golf club head that is able to reduce the sense of incongruity even when the face is closed at address.

A golf club head according to the invention includes a face portion, a crown portion and a sole portion, the crown portion including a first region extending in a toe-heel direction along at least part of the face portion, a second region arranged further on a back side than the first region, and a step region extending in the toe-heel direction between the first region and the second region and extending downward toward the second region from the first region side, the first region being formed to at least extend from a position Ph that is 20 mm on a heel side to a position Pt that is 25 mm on a toe side based on a face center, and a width Dh of the first region in a face-back direction at the position Ph and a width Dt of the first region in the face-back direction at the position Pt satisfying 1<(Dt/Dh)≤1.35.

In the above golf club head, a difference between the width Dh and the width Dt can be set to 6 mm or less.

In the above golf club heads, a length of the first region in the face-back direction can be set to 5 to 30 mm, between the position Ph and the position Pt.

In the above golf club heads, an angle θ formed by a straight line connecting the position Ph and the position Pt at an end edge on a face side of the first region and a straight line connecting the position Ph and the position Pt at the end edge on a back side of the first region can be configured to satisfy 0 degrees<θ≤8 degrees.

In the above golf club heads, a face angle FA of the face portion can be configured to satisfy −5 degrees≤FA≤0 degrees.

With a golf club head according to the present invention, the sense of incongruity can be reduced even when the face is closed at address.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a golf club head according to the present embodiment as seen from the face side.

FIG. 2 is a perspective view of the golf club head in FIG. 1 as seen from the back side.

FIG. 3 is a plan view of a reference state of the head in FIG. 1.

FIG. 4 is a cross-sectional view along an A-A line in FIG. 3.

FIG. 5A is a diagram illustrating the boundary of a face portion.

FIG. 5B is a diagram illustrating the boundary of the face portion.

FIG. 6 is a plan view showing the head at address.

FIGS. 7A to 7C are plan views showing other examples of the raised portion.

EMBODIMENTS OF THE INVENTION

Hereinafter, an embodiment of a golf club head according to the present invention will be described, with reference to the drawings. FIG. 1 is a perspective view of this golf club head as seen from the face side, FIG. 2 is a perspective view of this golf club head as seen from the back side, FIG. 3 is a plan view of the head in a reference state, and FIG. 4 is a cross-sectional view along an A-A line in FIG. 3. Note that the reference state of the golf club head will be discussed later.

1. Overview of Golf Club Head

As shown in FIGS. 1 to 4, this golf club head (hereinafter, may be simply referred to as “head”) 100 is a wood-type golf club head having a hollow structure with an internal space, and a wall surface is formed by a face portion 1, a crown portion 2, a sole portion 3 and a hosel portion 4. Specifically, the present invention is applicable to golf club heads such as utilities, fairway woods and drivers.

The face portion 1 has a face surface which is the surface that hits the ball, and the crown portion 2 adjoins the face portion 1 and constitutes the upper surface of the head 100. The sole portion 3 mainly constitutes the bottom surface of the head 100, and constitutes the outer peripheral surface of the head 100 other than the face portion 1 and the crown portion 2. That is, besides the bottom surface of the head 100, the region extending from the toe side of the face portion 1 around the back side of the head to the heel side of the face portion 1 is also part of the sole portion 3. Furthermore, the hosel portion 4 is a region that is provided adjoining the heel side of the crown portion 2, and has an insertion hole 41 into which the shaft (illustration omitted) of the golf club is inserted. A center axis line Z of this insertion hole 41 coincides with the axis line of the shaft.

Here, the reference state when setting the golf club head 100 on the ground will be described. First, as shown in FIGS. 3 and 4, a state where the above center axis line Z is contained in a plane P1 that is perpendicular to the ground and the head is placed on the ground at a predetermined lie angle and real loft angle is prescribed as the reference state. The above plane P1 will be referred to as the reference perpendicular plane. Also, as shown in FIG. 3, the line of intersection between the above reference perpendicular plane P1 and the ground will be referred to as the toe-heel direction, and the direction perpendicular to this toe-heel direction and parallel to the ground will be referred to as the face-back direction. Also, the direction that is orthogonal to the toe-heel direction and the face-back direction may be referred to as the up-down direction.

In the present embodiment, the boundary between the face portion 1 and the crown portion 2 and between the face portion 1 and the sole portion 3 can be defined as follows. That is, in the case where a ridgeline is formed therebetween, this ridgeline will be the boundary. On the other hand, in the case where a clear ridgeline is not formed, in each of cross-sections E1, E2, E3 and so forth that contain a straight line N connecting a head center of gravity G and a sweet spot SS, as shown in FIG. 5A, a position Pe at which a curvature radius r of a contour line Lf of the face outer surface first reaches 200 mm in a direction toward the face outer side from the sweet spot side, as shown in FIG. 5B, will be the periphery of the face portion 1, and this periphery is defined as the boundary with the crown portion 2 or the sole portion 3. Note that the sweet spot SS is the point of intersection between the normal (straight line N) of the face surface that passes through the head center of gravity G and this face surface.

Also, in the present embodiment, the boundary between the crown portion 2 and the sole portion 3 can be defined as follows. That is, in the case where a ridgeline is formed between the crown portion 2 and the sole portion 3, this ridgeline will be the boundary. On the other hand, in the case where a clear ridgeline is not formed therebetween, the contour when the head is set in the reference state and viewed from directly above the center of gravity of the head 100 will be the boundary.

Also, the head 100 can, for example, be formed with a titanium alloy (Ti-6Al-4V) having a specific gravity of substantially about 4.4 to 4.5. Also, apart from a titanium alloy, the head can also be formed using one or two or more materials selected from stainless steel, maraging steel, an aluminum alloy, a magnesium alloy and an amorphous alloy, for example.

Also, the volume of this golf club head 100 is from 80 cm³ to 460 cm³ inclusive, for example.

2. Assembly Structure of Golf Club Head

The golf club head 100 according to the present embodiment is constituted, as shown in FIG. 4, by assembling a head main body 101 having a crown portion 2 and a sole portion 3 and a cup-shaped face member 102 having a face portion 1 and a peripheral portion 15 extending from the periphery of the face portion. This head main body 101 has an opening 18 enclosed by the crown portion 2 and the sole portion 3, and the face member 102 is attached so as to close off this opening 18. That is, an end face of the peripheral portion 15 of the face member 102 is butted against an end face of the opening 18 of the head main body 101, and these portions are joined by welding (so-called cup face structure). The face member 102 is integrated with the head main body 101, by being attached to an edge portion of the opening 18 of the head main body 101, and the peripheral portion 15 of the face member 102 thereby functions as part of the crown portion 2 and the sole portion 3 of the head 100.

Accordingly, the surface that is integrally formed as a result of the peripheral portion 15 of the face member 102 being attached to the head main body 101 constitutes the crown portion 2 and the sole portion 3 of the head 100. Thus, strictly speaking, the crown portion 2 and the sole portion 3 of the head main body 101 are part of the crown portion 2 and the sole portion 3 of the head 100, although, in this specification, these portions of the head main body 101 may also be referred to simply as the crown portion 2 and the sole portion 3, without making this distinction.

3. Structure of Crown Portion

Next, the crown portion 2 will be described. As shown in FIGS. 1 to 4, the crown portion 2 is constituted by a raised portion (first region) 21 that is arranged on the face portion side and a base portion (second region) 22 that is arranged further on the back side than the raised portion 21. The raised portion 21 is mainly a band-like region extending in the toe-heel direction along the face portion 1, with the respective end portions on the toe and heel sides extending slightly to the back side along the periphery of the crown portion 2, and is formed as a whole to be U-shaped in plan view. Accordingly, the end edge on the back side of the raised portion 21 is slightly curved. On the other hand, the base portion 22 is a region that occupies most of the crown portion 2 at a lower position than the raised portion 21, and the periphery thereof contacts the sole portion 3. A sloped surface (step region) 23 that constitutes a step is formed on the boundary between the raised portion 21 and the base portion 22. The height of the face portion 1 in the up-down direction is thereby increased by the amount of the step between the raised portion 21 and the base portion 22.

This sloped surface 23 is configured so as to extend upward, moving toward the face portion 1 side. The sloped surface 23 can thereby be sighted from above, when the golf club head 100 is set in the reference state. That is, the sloped surface can be sighted by the golfer at address. The sloped surface 23 is formed along the raised portion 21, and is thus formed to be U-shaped in plan view, similarly to the raised portion 21.

As shown in FIG. 3, a width D of the raised portion 21 in the face-back direction can be prescribed as follows. That is, a position Pt that is 25 mm on the toe side and a position Ph that is 20 mm on the heel side from the face center C are prescribed. The raised portion 21 is formed such that Dt and Dh satisfy the following in equation (1), where Dt is the width of the raised portion at the position Pt and Dh is the width of the raised portion 21 at the position Ph.

1<(Dt/Dh)≤1.35  (1)

Note that (Dt/Dh) is preferably 1.3 or less, and more preferably 1.25 or less. Also, (Dt/Dh) is preferably 1.05 or more, and more preferably 1.1 or more.

That is, the raised portion 21 is formed such that Dt is greater than Dh. Specifically, the lengths of Dt and Dh are, for example, preferably set such as shown in the following in equations (2) and (3).

10 mm≤Dt≤30 mm  (2)

6.5 mm≤Dh≤30 mm  (3)

Within the range from the position Pt to the position Ph, the width D of the raised portion 21 preferably satisfies the following in equation (4).

5 mm≤D≤30 mm  (4)

Also, a difference Dn between Dt and Dh is preferably set as follows.

Dn≤6 mm  (5)

Note that Dn is more preferably set to 5 mm or less, and is particularly preferably set to 4 mm or less.

Also, a straight line L1 connecting an end edge Pt1 on the face side of the raised portion 21 at the position Pt and an end edge Ph1 on the face side of the raised portion 21 at the position Ph is prescribed. Furthermore, a straight line L2 connecting an end edge Pt2 on the back side of the raised portion 21 at the position Pt and an end edge Ph2 on the back side of the raised portion 21 at the position Ph is prescribed. In this case, an angle θ formed by the straight line L1 and the straight line L2 preferably satisfies the following in equation (6).

0<θ≤8 degrees  (6)

Note that the face center can be defined as follows.

First, an arbitrary point Po is determined generally in a vicinity of the middle of the face portion 1 (face surface) in the toe-heel direction and the up-down direction. A line x extending in the toe-heel direction is drawn through this point Po, and a midpoint Px of this line x is determined. Next, on the face portion 1, a line y extending in the up-down direction is drawn through the point Px, and a midpoint Py of this line is determined. A process of redrawing the line extending in the toe-heel direction through the point Py determined in this way as the line x and thereafter redetermining the point Py in a similar manner to that described above is then repeatedly performed. A new point Py at which the distance between the previous point Py and the new point Py becomes 0.5 mm or less during the repetitions of this process is defined as the face center. Note that, more specifically, the above line x passing through the point Po is the line of intersection between the face surface (surface of the face portion 1) and a plane that contains the normal of the face surface passing through this point Po and is parallel to the toe-heel direction. Also, more specifically, the above line y passing through the point Px is the line of intersection between the face surface and a plane that contains the normal of the face surface passing through this point Px and is parallel to the up-down direction. Also, more specifically, the above line x passing through the point Py is the line of intersection between the face surface and a plane that contains the normal of the face surface passing through this point Py and is parallel to the toe-heel direction. Note that the lengths of the above lines x and y are measured along the face surface.

Also, as shown in FIG. 4, a width W of the sloped surface 23 in the face-back direction in plan view is preferably set from 3 to 9 mm, and more preferably from 3 to 7 mm, for example. Furthermore, a height H of the sloped surface 23 is preferably set from 0.5 to 8 mm, more preferably from 0.5 to 6 mm, and particularly preferably from 0.5 to 5 mm, for example.

4. Structure of Face Portion and Sole Portion

The structure of the face portion 1 and the sole portion 3 is not particularly limited. With regard to the face portion 1, the thickness thereof can be appropriately changed, for example. Also, a face angle FA preferably satisfies the following in equation (7).

−5 degrees≤FA≤0 degrees  (7)

Note that the face angle FA is defined as follows. First, a straight line FL connecting two points F1 and F2 on the face surface at positions respectively spaced by 40 mm on the toe side and the heel side of the face center is drawn with the head in the reference state. The angle formed by this straight line FL and a straight line extending parallel to the toe-heel direction is defined as the face angle FA. Note that in the case where the points F1 and F2 cannot be taken on the face surface of the head due to the size of the face surface, a straight line connecting two points on the face surface at positions respectively spaced by 30 mm on the toe side and the heel side of the face center is determined as the straight line FL. Also, the sign of the face angle FA is positive in the case where the face is turned in a direction that closes the face (discussed above), and is negative in the case where the face is turned in a direction that opens the face (e.g., in a direction whereby the face is turned to the right of the target direction, in the case of a right-handed club).

Also, with regard to the structure of the sole portion 3, recesses and protrusions can be appropriately formed and the thickness can be changed from a design or performance viewpoint.

5. Manufacturing Method of Golf Club Head

Next, an example of the manufacturing method of the above golf club head will be described. First, the abovementioned head main body 101 and face member 102 are prepared. A head main body 101 and a face member 102 such as described above can be produced with various methods. For example, the head main body 101 can be manufactured by casting such as a well-known lost wax precision casting process. Also, the face member 102 can be manufactured by a method such as forging, plate pressing or casting, for example.

The golf club head is then completed when predetermined coating is performed after joining these portions by welding (TIG (tungsten inert gas) welding, plasma welding, laser welding, brazing, etc.), for example.

6. Features

According to the above embodiment, the following effects can be obtained.

(1) In the crown portion 2, the raised portion 21 is formed higher than the base portion 22 via the sloped surface 23, thus enabling the height of the face portion 1 to be increased by the height of the raised portion 21. Thus, the rebound performance of the face portion 1 can be improved. Also, in the crown portion 2, only the raised portion 21 is formed higher, and the base portion 22 occupying most of the crown portion 2 is formed at a lower position than the raised portion 21, thus enabling the center of gravity of the head to be lowered.

(2) At address, the orientation of the head can be determined utilizing the end edge on the back side of the raised portion 21. At this time, since the widths Dt and Dh of the raised portion 21 satisfy in equation (1), the end edge on the back side of the raised portion 21 extends such that the distance between the end edges of the raised portion 21 on the back and face sides is greater at the position Pt on the toe side than at the position Ph on the heel side. Thus, the following effects can be obtained.

Golfers, in order to better catch the ball or to prevent slicing, sometimes intentionally grip the club at address with the face rotated in a direction that closes the face (e.g., in a direction whereby the face is turned to the left of the target direction, in the case of a right-handed club). At this time, the upper end edge of the face surface (end edge on the face side of the raised portion 21) slopes relative to the target line rather than being orthogonal thereto, whereas the end edge on the back side of the raised portion 21, due to satisfying the above in equation (1), extends in a direction orthogonal to the target line. That is, as shown in FIG. 6, the straight line L1 along the end edge on the face side of the raised portion 21 slopes relative to the target line rather than being orthogonal thereto, whereas the straight line L2 along the end edge on the back side of the raised portion 21 extends so as to be generally orthogonal to the target line. Thus, at address, the orientation of the end edge on the back side of the raised portion 21, rather than the upper end edge of the face surface, can be aligned with the target. Accordingly, the golfer is able to address the ball without feeling any sense of incongruity, even with the face surface in a closed state.

(3) Also, when the above in equations (2) to (6) are satisfied in addition to the above in equation (1), the golfer is better able to address the ball without feeling any sense of incongruity, even with the face surface in a closed state.

(4) Also, when the above in equation (7) is satisfied, the face is square (orthogonal to the target line) or the face is open (e.g., face is turned to the right of the target direction, in the case of a right-handed club), in the reference state. Thus, when the club is gripped at address with the head in the reference state, the end edge on the back side of the raised portion 21 extends in a direction that is open to the target direction (e.g., in a direction whereby the direction orthogonal to the end edge on the back side of the raised portion 21 is turned to the right of the target direction, in the case of a right-handed club). Golfers tend to feel a sense of incongruity in the case where the point of reference at address is turned in a direction that is closed relative to the target direction. Therefore, this sense of incongruity can be eliminated by satisfying the above in equation (7).

7. Variations

Although an embodiment of the present invention is described above, the present invention is not particularly limited to the above embodiment, and various modifications can be made without departing from the spirit of the invention. Also, the following variations can be appropriately combined. Modifications such as the following can be made, for example.

<7-1>

In order to obtain the abovementioned effects, the raised portion 21 need only be formed such that at least in equation (1) is satisfied. Accordingly, in equations (2) to (7) need only be appropriately set if needed.

In the above embodiment, the raised portion 21 is formed to be U-shaped in plan view, but is not particularly limited thereto. That is, as long as in equation (1) is satisfied, an end edge 211 on the back side of the raised portion 21 can, for example, be formed linearly, as shown in FIG. 7A, can be formed to bend at one or a plurality of places between the position Pt and the position Ph, as shown in FIG. 7B, or can be formed to curve, as shown in FIG. 7C.

<7-2>

In the above embodiment, the sloped surface 23 is formed to be U-shaped in plan view, but is not limited thereto, and need only extend generally in the toe-heel direction. Accordingly, the sloped surface 23 can also be formed in a band shape extending generally straight in the toe-heel direction, for example. Also, the sloped surface 23 may not necessarily be flat. For example, the sloped surface can also be formed to be curved. Furthermore, the region between the raised portion 21 and the base portion 22 need not necessarily be formed as a slope, and may be a step that extends in the up-down direction.

<7-3>

The head according to the above embodiment is constituted by combining a head main body having at least the crown portion 2 with other portions, but the present invention can also be applied to a head in which only the crown portion 2 is formed separately. For example, the head can be constituted by fitting the crown portion 2 into an opening for the crown portion formed in a head main body that includes a face portion, a side portion and a sole portion. Also, a cup face structure need not be adopted, and the head can be constituted by fitting a plate-like face member into an opening formed in the face portion 1 and welding the face member to the head main body.

Working Examples

Hereinafter, working examples of the present invention will be described. The present invention is, however, not limited to the following working examples.

Here, golf club heads having generally the same shape as FIGS. 1 to 4 were produced as working examples 1 and 2 satisfying the above in equation (1), as described above, and as comparative examples 1 and 2 not satisfying the above in equation (1).

Working example 1     Dt/Dh = 1.2 (Dt = 22.0 mm, Dh = 18.3 mm)
Working example 2     Dt/Dh = 1.3 (Dt = 23.8 mm, Dh = 18.3 mm)
Comparative example 1 Dt/Dh = 1 (Dt = 18.3 mm, Dh = 18.3 mm)
Comparative example 2 Dt/Dh = 1.4 (Dt = 25.7 mm, Dh = 18.3 mm)

Twenty golfers tested the golf clubs produced as described above. That is, sensory analysis was conducted in fine weather conditions as to whether any sense of incongruity was felt when the face surface was closed at address. As a result, with working examples 1 and 2, all of the golfers responded that they did not feel any sense of incongruity at address.

On the other hand, with the comparative example 1, 60 percent of the golfers responded that they felt a sense of incongruity at address. With the comparative example 1, the end edge on the face side and the end edge on the back side of the raised portion were parallel to each other, and thus the sense of incongruity was apparently due to the fact that not only the end edge on the face side of the raised portion but also the end edge on the back side was not orthogonal to the target line (the toe side was angled to the face side), when the face surface was closed at address.

Also, with the comparative example 2, 25 percent of the golfers responded that they felt a sense of incongruity at address. With the comparative example 2, the width of the raised portion on the toe side was much greater than on the heel side, and thus the angle formed by the end edge on the face side of the raised portion and the end edge on the back side was apparently felt to be excessively large. Thus, a sense of incongruity was apparently felt due to the fact that the end edge on the back side of the raised portion was not orthogonal to the target line (the toe side was angled steeply to the back side), when the face surface was closed at address.

LIST OF REFERENCE NUMERALS

• • 1 Face portion
  • 2 Crown portion
  • 21 Raised portion (first region)
  • 22 Base portion (second region)
  • 23 Sloped surface (step region)
  • 3 Sole portion
  • 4 Hosel portion

Claims

1. A golf club head comprising:

a face portion;

a crown portion; and

a sole portion,

wherein the crown portion includes:

a first region extending in a toe-heel direction along at least part of the face portion;

a second region arranged further on a back side than the first region; and

a step region extending in the toe-heel direction between the first region and the second region, and extending downward toward the second region from the first region side,

the first region is formed to at least extend from a position Ph that is 20 mm on a heel side to a position Pt that is 25 mm on a toe side, based on a face center, and

a width Dh of the first region in a face-back direction at the position Ph and a width Dt of the first region in the face-back direction at the position Pt satisfy 1<(Dt/Dh)≤1.35.

2. The golf club head according to claim 1, wherein (Dt/Dh) is 1.3 or less.

3. The golf club head according to claim 1, wherein (Dt/Dh) is 1.25 or less.

4. The golf club head according to claim 1, wherein (Dt/Dh) is 1.05 or more.

5. The golf club head according to claim 1, wherein (Dt/Dh) is 1.1 or more.

6. The golf club head according to claim 1, wherein a difference between the width Dh and the width Dt is 6 mm or less.

7. The golf club head according to claim 1, wherein a length of the first region in the face-back direction is 5 to 30 mm, between the position Ph and the position Pt.

8. The golf club head according to claim 1, wherein Dt is 10 to 30 mm.

9. The golf club head according to claim 1, wherein Dh is 6.5 to 30 mm.

10. The golf club head according to claim 1, wherein an angle θ formed by a straight line connecting the position Ph and the position Pt at an end edge on a face side of the first region and a straight line connecting the position Ph and the position Pt at the end edge on a back side of the first region satisfies 0 degrees<θ≤8 degrees.

11. The golf club head according to claim 1, wherein a face angle FA of the face portion satisfies −5 degrees≤FA≤0 degrees.

12. The golf club head according to claim 1, wherein the step region is formed to be substantially U-shaped in plan view.

13. The golf club head according to claim 1, wherein the end edge on a back side of the first region between the position Ph and the position Pt is formed linearly.

14. The golf club head according to claim 1, wherein the end edge on a back side of the first region between the position Ph and the position Pt is formed to curve.

15. The golf club head according to claim 1, wherein the end edge on a back side of the first region between the position Ph and the position Pt is formed to bend at least one place.