JP7581639B2 - Golf club head and golf club - Google Patents

Description

The present invention relates to an iron-type golf club head and a golf club.

Traditionally, in iron-type golf clubs, attempts have been made to increase the moment of inertia by distributing a large amount of weight to the outside of the head in order to reduce head wobble on mishits.

For example, the following Patent Document 1 describes how forming a hole in the joint (heel) that connects the face plate of the head body to the neck reduces the weight of the joint and moves the head's center of gravity to the toe, thereby increasing the head's moment of inertia.

JP 2005-103160 A

However, while the technology described in Patent Document 1 does indeed move the center of gravity to the toe, the volume of the hole formed in the connection is limited, so the moment of inertia is not significantly improved.

In view of the above, the object of the present invention is to provide an iron-type golf club head and golf club that can achieve a higher moment of inertia than conventional golf clubs.

To achieve the above object, a golf club head according to one embodiment of the present invention is an iron-type golf club head having a toe portion, a heel portion including a hosel, and a center portion located between the toe portion and the heel portion and centered on the center of gravity. The weight of the center portion is 30% or less of the total weight of the golf club head.

This allows the weight of the center section to be kept to 30% or less, while increasing the weight of the toe or heel section, resulting in a higher moment of inertia (lateral moment of inertia) than before.

The boundary that divides the center portion from the toe portion and the heel portion is formed by two surfaces that are each 21.335 mm from the center of gravity and perpendicular to the toe-heel direction. Alternatively, the boundary may be formed at a distance of 25 mm from the center of gravity, or at a distance of 25 mm from the center of the scoreline of the face portion.

The weight of the heel portion may be 25-40% of the total weight.

The heel portion may have a heel-side extension portion located in a blind spot of a player when the player addresses a golf club having the golf club head.

This allows the weight of the heel to be increased to achieve a high moment of inertia, while still allowing the player to address the ball with the same ease as with a conventional golf club.

The heel-side extension portion may be provided on the lower part of the heel portion, on the opposite side of the shaft axis from the center portion.

This allows the weight to be distributed to the lower part of the heel, farther from the center of gravity and to the outside of the shaft axis, resulting in a high moment of inertia.

When the golf club head is divided into a heel side and the rest by a plane that passes through the shaft axis of the heel portion and is perpendicular to the face surface, the weight of the heel side may be 13% or more of the total weight.

The weight of the hosel wall surrounding the shaft insertion hole of the hosel may be 8% or more of the total weight.

This allows for a high moment of inertia to be achieved by distributing weight to the hosel, which is farther from the center of gravity in the heel section.

The weight of the toe portion may be 40-60% of the total weight.

The toe portion may have a toe-side extension portion located in a blind spot of a player when the player addresses a golf club having the golf club head.

This allows the weight of the toe to be increased to achieve a high moment of inertia, while still allowing the player to address the ball with the same ease as with a conventional golf club.

The toe side extension portion may be provided below the toe portion and on the back face side.

This allows the weight to be distributed to the lower part of the toe, farther from the center of gravity and toward the back face, resulting in a high moment of inertia.

The weight of the toe-side extension that extends beyond the contour of the face surface of the golf club head in a front view of the face surface may be 10% or more of the total weight.

This allows the weight around the face to be maximized, resulting in a high moment of inertia.

The total weight may be between 230 and 300 g.

This allows a high moment of inertia to be achieved even with relatively heavy irons.

The length from the end of the heel portion opposite the center portion to the end of the toe portion opposite the center portion may be 135 mm or less.

This allows irons with relatively long head lengths to achieve a high moment of inertia.

The moment of inertia of the center of gravity about the vertical axis may be 4000 g·cm^2 or more.

The height of the center of gravity when projected onto the face of the golf club head may be 22 mm or less.

The heel portion may have a cavity in the lower portion of the hosel and an opening on the back face side of the lower portion that communicates with the cavity.

This allows for the creation of a hollow space and an opening in the lower part of the hosel, which creates excess weight and places it farther away from the center of gravity, increasing the moment of inertia.

The golf club may have a top blade having a thickness of 4 mm or less, the top blade extending from the toe portion to the lower end of the hosel, and may form part of the cavity and the opening.

This allows the head to be lighter and the center of gravity to be lowered by reducing the weight of the upper part of the head.

When the area of the back surface of the face of the golf club head exposed to the back face side is divided by a vertical line passing through the center of gravity, the area ratio of the heel side area to the toe side area may be 0.75 to 1.5. In this case, the heel side area may include the area exposed from the opening.

This creates a larger opening area on the back face that extends further toward the heel than before, creating excess weight that can be positioned farther away from the center of gravity to increase the moment of inertia.

The change in thickness of the sole portion of the center portion may be 20% or less.

This allows the thickness of the sole part in the center to be reduced, and the resulting weight to be placed in the heel or toe, increasing the moment of inertia.

A golf club according to another aspect of the present invention has any of the golf club heads described above and a golf club shaft attached to the golf club head.

As described above, the present invention can provide an iron-type golf club head and golf club that can achieve a higher moment of inertia than conventional golf clubs. However, this effect does not limit the present invention.

1 is a front view of a head portion of a golf club according to a first embodiment of the present invention. FIG. FIG. FIG. 2 is a side view of the head portion as viewed from the heel side. 2 is a cross-sectional view taken along line AA of FIG. 1. This is a cross-sectional view taken along line B-B of FIG. FIG. 2 is a rear view of the head portion showing an exposed area of the back surface of the face. 10A and 10B are diagrams showing a method for calculating the weight distribution of each part of the head. FIG. 9 is a diagram showing an example of a calculation result based on the calculation method shown in FIG. 8 . FIG. 9 is a diagram showing another example of the calculation result based on the calculation method shown in FIG. 8 . FIG. 11 is a front view of a head portion of a golf club according to a second embodiment of the present invention. This is a cross-sectional view taken along the line CC of FIG. FIG. 11 is a front view of a head portion of a golf club according to a third embodiment of the present invention. This is a cross-sectional view taken along the line D-D of FIG.

The following describes an embodiment of the present invention with reference to the drawings.

[First embodiment]
First, a first embodiment of the present invention will be described.

Figure 1 is a front view showing the appearance of the golf club head portion of the golf club according to this embodiment, Figure 2 is a rear view of the head portion, Figure 3 is a plan view of the head portion, and Figure 4 is a side view of the head portion as seen from the heel side. Also, Figure 5 is a cross-sectional view taken along line A-A in Figure 1, and Figure 6 is a cross-sectional view taken along line B-B in Figure 1.

As shown in these figures, the golf club 100 according to this embodiment has an iron-type golf club head 10 (hereinafter also simply referred to as head 10) and a golf club shaft 15 attached to the golf club head 10.

The golf club shaft 15 is attached to the golf club head 10 via, for example, a socket (not shown), but may also be attached directly without a socket.

The golf club head 10 has a toe portion 1, a heel portion 2, and a center portion 3. The heel portion 2 has a hosel 4, and the center portion 3 is located between the toe portion 1 and the heel portion 2 and is formed around the center of gravity G of the head 10. The hosel 4 has a shaft insertion hole 4a for inserting the golf club shaft 15.

The head 10 also has a face 5 which is the hitting surface, and the heel portion 2 has a connecting portion 20 which connects the face 5 to the hosel 4. A top blade 5a is formed at the upper end of the face 5, and a sole 6 is formed from the lower end of the face 5 to the back side. A cavity portion 7 is formed on the back side of the face 5 so that the back side of the face 5 is exposed.

As shown in FIG. 2, the boundary b1 between the toe portion and the center portion 3, and the boundary b2 between the heel portion 2 and the center portion 3, are formed by two surfaces that are each 21.335 mm away from the center of gravity G of the head 10 and perpendicular to the toe-heel direction. This is because the Rules of Golf Equipment define the impact area as a strip that passes through the center of gravity and has a width of 42.67 mm.

Alternatively, the boundaries b1 and b2 may be formed at a distance of 25 mm in the toe-heel direction from the center of gravity G, or at a distance of 25 mm in the toe-heel direction from the center of the scoreline formation area of the face 5.

The head 10 is integrally formed by casting and forging from a material such as stainless steel, e.g. AM355, and its total weight is larger than that of a typical iron-type golf club head, e.g. 230 to 300 g.

In this case, the weight of the center portion 3 is, for example, 30% or less of the total weight of the head 10. In this case, the weight of the heel portion 2 may be 25 to 40% of the total weight of the head 10. Also, in this case, the weight of the toe portion 1 may be 40 to 60% of the total weight of the head 10.

In this case, the length of the head 10 in the toe-heel direction (X direction) (the length from the outer end of the toe portion 1 to the outer end of the heel portion 2 in the X direction) is 135 mm or less.

This allows the weight of the center section to be kept below 30% and the weight of the toe section 1 and/or heel section 2 to be increased, resulting in a higher moment of inertia (lateral moment of inertia) than conventional heads.

To achieve this weight distribution, the toe portion 1 of the head 10 has a toe-side extension portion 11 that extends vertically (Y direction) from its lower portion toward the back face, and the heel portion 2 has a heel-side extension portion 21 that extends vertically (Y direction) from its lower portion toward the opposite side of the center portion 3 with respect to the shaft axis S. The toe-side extension portion 11 and heel-side extension portion 21 function as weights.

Specifically, the toe-side extension portion 11 has a right-angled triangular pyramid shape formed by extending the toe-side side of the face 5 vertically and sharing the bottom surface with the sole 6.

As shown in FIG. 1, the weight of the portion of the toe-side extension 11 that extends beyond the contour 5e of the face 5 of the head 10 in a front view of the face 5 may be 10% or more of the total weight of the head 10.

The heel-side extension portion 21 has a plate shape in which the portion of the heel portion 2 that is closer to the heel in the toe-heel direction than the shaft axis S protrudes obliquely downward in an arch shape that is nearly perpendicular to the shaft axis S in the XY plane of each figure.

Also, as shown in FIG. 1, the heel-side extension portion 21 may be formed so that when the head 10 is divided into the heel portion 2 side and the rest by a plane that passes through the shaft axis S and is perpendicular to the face surface, the weight of the heel portion 2 side is 13% or more of the total weight of the head 10.

As shown in FIG. 3, the toe side extension portion 11 and the heel side extension portion 21 are formed in a position that is in the player's blind spot when the player addresses the golf club 100 (a position that is hidden by a portion located above the toe side extension portion 11 and the heel side extension portion 21 and is therefore not visible to the player).

This allows the weight of the toe portion 1 and heel portion 2 to be increased to achieve a high moment of inertia, while still allowing the player to address the ball with the same ease as with a conventional golf club.

As shown in Figures 2, 4, and 6, the connecting portion 20 has a horn-shaped cavity 22 whose volume gradually increases from just below the hosel 4 toward the center portion 3. The back face side of the connecting portion 20 has an opening 23 that communicates with the cavity 22. The heel side extension portion 21 is formed on the heel side of the cavity 22 (the portion of the connecting portion 20 that is on the heel side of the cavity 22 becomes the heel side extension portion 21).

By hollowing out the connecting portion 20 and forming the opening 23 in this way, excess weight is generated, and by placing the excess weight on the heel side, the lateral moment of inertia can be significantly increased without increasing the height of the center of gravity, and the decrease in initial velocity on off-center hits can be reduced.

At the same time, the connecting portion 20 is made thinner, which increases the coefficient of restitution (COR) of the face 5, particularly the heel side, and the opening 23 allows the center of gravity to be lowered.

Figure 7 shows the region R (cavity portion 7) exposed on the back face side of the back surface of the face 5 of the head 10. This region R includes the region exposed from the opening 23.

As shown in the figure, when the region R is divided by a vertical line passing through the center of gravity G (the point where the center of gravity G is projected onto the region R), the ratio of the area S1 of the region on the heel portion 2 side to the area S2 of the region on the toe portion 1 side is 0.75 to 1.5.

This creates a larger opening area R on the back face that spreads further toward the heel portion 2 than before, creating excess weight that can be positioned farther away from the center of gravity to increase the moment of inertia.

As shown in Figures 2 and 4, the top blade 5a has a thickness of 4 mm or less, extends from the toe portion 1 to the connecting portion 20 (the lower end of the hosel 4), and forms part of the cavity 22 and the opening 23.

This allows the upper part of the head 10 to be lighter, thereby lowering the center of gravity G.

The hosel 4 has an outer diameter larger than that of a conventional hosel, and its lower end is tapered downward. By making the diameter larger than that of a conventional hosel, the weight of the hosel wall 4b around the shaft insertion hole 4a of the hosel 4 is set to 8% or more of the total weight of the head 10.

This allows the weight to be distributed to the hosel 4, which is the part of the heel portion 2 that is farther from the center of gravity, thereby achieving a high moment of inertia.

As shown in Figures 2, 5, and 6, the rate of change in thickness of the sole 6 in the center portion 3 may be 20% or less. This reduces the thickness of the sole portion of the center portion 3 over a wide range, and by distributing the resulting weight in the heel portion 2 or toe portion 1, it is possible to increase the moment of inertia.

With the above configuration, the moment of inertia (lateral moment of inertia) around the vertical axis of the center of gravity G of the head 10 is 4000 g·cm^2 or more.

In addition, the height of the center of gravity G when projected onto the face 5 of the head 10 is set to 22 mm or less.

To achieve this moment of inertia and center of gravity height, the inventor performed calculations to determine how much weight should be distributed to which part of the head.

Figure 8 shows a method for calculating the weight distribution of each part of the head 10. As shown in the figure, four points (A, B, C, D) where weights are placed on an iron-type head with no excess weight are determined, and the weight distribution and moment of inertia of the four points are calculated using formula 1 in the figure. At this time, the center of gravity area and weight to be achieved are also set. Of the four points, A corresponds to the position of the hosel 4, B corresponds to the heel side extension part 21, C corresponds to the toe side extension part 11, and D corresponds to the upper end of the toe part 1.

In this formula 1, M is the total weight of the head 10 after the target weight distribution, mo is the initial weight of the head 10 before the weight distribution, MOI0 is the moment of inertia of the head 10 before the weight distribution, xg, yg, zg are the coordinates of the target center of gravity G, and I is the length from the installation point of each weight to the target center of gravity.

By using this formula 1, it is possible to determine the weight distribution that achieves the maximum moment of inertia in the center of gravity area to be designed.

Figure 9 shows an example of the calculation results based on the calculation method shown in Figure 8 above. In this example, it is assumed that the head 10 is integrally cast from stainless steel and the total weight (mo) of the head 10 before weight distribution is 127.6 g.

As shown in the figure, by allocating weights of 19.2g and 18.4g to part A (hosel 4) and part B (heel side extension 21), respectively, and allocating nearly five times that amount, 89.7g, to part C (toe side extension 11), and allocating almost no weight to part D (upper end of the toe), a moment of inertia of 4154gcm^2 and a center of gravity height of 17.28mm are achieved.

Figure 10 shows another example of the calculation results based on the calculation method shown in Figure 8 above. In this example, it is assumed that the head 10 is manufactured by allocating tungsten as a weight to a titanium head before weight distribution, and the total weight (mo) of the head 10 before weight distribution is 72.9 g. The tungsten member is joined to the head before weight distribution by welding or the like.

As shown in the figure, weights of 37.3g and 35.4g are allocated to part A (hosel 4) and part B (heel side extension 21), respectively, and nearly three times as much weight, 108.8g, is allocated to part C (toe side extension 11), with almost no weight allocated to part D (upper end of the toe), achieving a moment of inertia of 5446gcm^2 and a center of gravity height of 17.28mm. By allocating weight in this way using a metal different from the material of a typical head, it is possible to achieve a higher moment of inertia than with one-piece casting.

[summary]
As described above, according to this embodiment, it is possible to provide an iron-type golf club head having a higher moment of inertia and a lower center of gravity than conventional golf clubs by distributing the weight to the lower portions of the toe portion 1 and heel portion 2. Also, by hollowing out the connecting portion 20 of the heel portion 2, it is possible to increase the coefficient of restitution (COR) of the face, particularly the COR on the heel side.

[Second embodiment]
Next, a second embodiment of the present invention will be described. In this embodiment and the following embodiments, parts having the same functions and configurations as those in the first embodiment are given the same reference numerals, and descriptions thereof will be omitted or simplified.

In the above embodiment, the head 10 has both the toe side extension portion 11 and the heel side extension portion 21, but either the toe side extension portion 11 or the heel side extension portion 21 may not be provided.

Furthermore, the shape and size of the toe side extension portion 11 and the heel side extension portion 21 are not limited to those shown in the first embodiment.

Figure 11 is a front view of the head portion of a golf club according to this embodiment, and Figure 12 is a cross-sectional view taken along line CC of Figure 11.

As shown in both figures, in this embodiment, the head 10 has only the heel-side extension portion 21 out of the toe-side extension portion 11 and the heel-side extension portion 21. In addition, the heel-side extension portion 21 in this embodiment has an oblique quadrangular prism shape in which the front and back surfaces parallel to the face 5 are approximately parallelograms.

As shown in FIG. 12, in the heel portion 2 according to this embodiment, the portion of the connecting portion 20 that faces the opening 23 and is adjacent to the face 5 (the face-side connecting portion 24) has the same thickness as the face 5 so as to form part of the face 5. This face-side connecting portion 24 may be formed up to just below the bottom surface of the shaft insertion hole of the hosel 4 (the limit position where it does not penetrate the bottom surface).

By extending the face 5 all the way to the connecting portion 20, the restitution coefficient of the entire face can be further improved.

[Third embodiment]
Next, a third embodiment of the present invention will be described.
In each of the above-mentioned embodiments, the toe side extension portion 11 and/or the heel side extension portion 21 were provided for the purpose of increasing the moment of inertia of the head 10, but if the purpose is not to achieve a high moment of inertia but to increase the coefficient of repulsion, it is not necessarily necessary to provide the toe side extension portion 11 and the heel side extension portion.

Figure 13 is a front view of the head portion of a golf club according to this embodiment, and Figure 14 is a cross-sectional view taken along line D-D of Figure 13.

As shown in both figures, the head 10 according to this embodiment is the head 10 shown in the second embodiment above, with the heel-side extension portion 21 removed. Even with this configuration, the face 5 can be extended to the connecting portion 20, further improving the restitution coefficient of the entire face.

[Modification]
The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit and scope of the present invention.

For example, the values of weight, area, length, ratio, etc. shown in each of the above embodiments are not limited to those described above and can be changed as appropriate.

In the above embodiment, the head 10 is manufactured by integral casting or welding of dissimilar metal materials, but the head 10 may be manufactured by other methods, for example, by a 3D printer.

In the above embodiment, a middle iron head with a loft angle of about 30 degrees is shown, but the present invention can be applied to short irons and wedges with larger loft angles, as well as long irons and utility irons with smaller loft angles.

REFERENCE SIGNS LIST 1: toe portion 2: heel portion 3: center portion 4: hosel 4a: shaft insertion hole 4b: hosel wall 5: face 5a: top blade 6: sole 7: cavity portion 11: toe side extension portion 20: connecting portion 21: heel side extension portion 22: hollow portion 23: opening 24: face side connecting portion 10: golf club shaft 100: golf club G: center of gravity

Claims (15)

An iron-type golf club head,
a toe portion, a heel portion including a hosel, and a center portion located between the toe portion and the heel portion and centered on the center of gravity of the golf club head;
the heel portion has a heel-side extension portion located at a lower portion of the heel portion on the opposite side to the center portion with respect to the shaft axis and protruding in a vertically obliquely downward direction with respect to the shaft axis,
the sum of the weight of the center portion, the weight of the heel portion, and the weight of the toe portion is a total weight of the golf club head,
the weight of the center portion is 30% or less of the total weight,
the weight of the heel portion is 25 to 40% of the total weight;
The weight of the toe portion is 40 to 60% of the total weight,
a weight of a hosel wall surrounding a shaft insertion hole of the hosel is 8% or more of the total weight of the golf club head. 2. The golf club head of claim 1,
a boundary dividing the center portion from the toe portion and the heel portion, the boundary being formed by two planes perpendicular to a toe-heel direction and spaced 21.335 mm from the center of gravity. 3. The golf club head according to claim 1,
The heel-side extension portion is provided at a position that is in a blind spot of a player when the player addresses a golf club having the golf club head. 4. The golf club head according to claim 1,
When the golf club head is divided into a heel portion side and a remainder side by a plane that passes through the shaft axis of the heel portion and is perpendicular to a face surface, the weight of the heel portion side is 13% or more of the total weight. 5. The golf club head according to claim 1,
The toe portion has a toe-side extension portion located in a blind spot of a player when the player addresses a golf club having the golf club head. 6. The golf club head according to claim 5,
the toe-side extension portion is provided below the toe portion and on the back face side. 7. The golf club head according to claim 5,
a weight of a portion of the toe-side extension that protrudes from a contour of a face surface in a front view of the face surface of the golf club head is 10% or more of the total weight. 8. The golf club head according to claim 1,
The golf club head has a total weight of 230 to 300 g. 9. The golf club head according to claim 1,
a length from an end of said heel portion opposite said center portion to an end of said toe portion opposite said center portion being 135 mm or less. 10. The golf club head according to claim 1,
The golf club head has a moment of inertia about a vertical axis of the center of gravity of 4000 g·cm^2 or more. 11. A golf club head according to claim 1,
A golf club head, wherein the height of the center of gravity when projected onto a face surface of the golf club head is 22 mm or less. 12. A golf club head according to claim 1,
A top blade having a thickness of 4 mm or less,
the heel portion has a hollow portion in a lower portion of the hosel and an opening portion communicating with the hollow portion on a back face side of the lower portion,
The top blade extends from the toe portion to a lower end of the hosel and forms part of the cavity and the opening. 13. The golf club head of claim 12 ,
When a region of the back surface of the face of the golf club head exposed to the back face side is divided by a vertical line passing through the center of gravity, the area ratio of the heel side region to the toe side region is 0.75 to 1.5,
The golf club head, wherein the heel side region includes a region exposed through the opening. 14. A golf club head according to claim 1,
The golf club head has a thickness change rate of 20% or less in the sole portion of the center portion. A golf club head according to any one of claims 1 to 14,
a golf club shaft attached to the golf club head.

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