GOLF CLUB HEAD

Abstract

A golf club head according to the present invention is provided with a head body having a crown portion and a sole portion, and having an opening surrounded by the crown portion and the sole portion, and a face member closing the opening of the head body, the face member being formed in a cup shape having a planar face portion and a peripheral portion extending from a periphery of the face portion, the peripheral portion having a thick portion joined to an end face of the opening of the head body, and a connecting portion connecting the thick portion and the face portion, and, in the connecting portion, a thickness of a portion connected to the thick portion being thinner than the thick portion.

Description

TECHNICAL FIELD

The present invention relates to a golf club head.

BACKGROUND ART

Wood-type golf club heads have undergone many refinements heretofore, and various proposals have been made in order to extend the carry distance. For example, as shown in JP 2007-54198A, some wood-type golf club heads employ a face member having a so-called cup face structure. Specifically, the golf club head is constituted by a head body in which an opening is formed, and a face member that closes the opening in the head body, and the face member is formed in a cup shape having a planar face portion and a peripheral portion extending from the periphery of the face portion. The golf club head is formed, by joining the peripheral portion of the face member and the opening periphery of the head body by welding. With such a cup face structure, the welded portion of the face member and the head body will be away from the periphery of the face portion on the back side of the head. Thus, it is possible to lower the rigidity of the face portion, in comparison with a golf club head in which the face member is planar, and consequently the advantage of high rebound performance is obtained.

JP 2007-54198A is an example of related art.

Incidentally, with the cup face structure, rigidity increases and rebound performance decreases when the peripheral portion of the face member has a large thickness, and thus the peripheral portion is preferably thin. However, when the peripheral portion is made thinner, there is a risk that welding defects will occur during the welding, resulting in holes opening up in the peripheral portion or large deformations occurring. The present invention has been made in order to solve the above problem, and an object thereof is to provide a golf club head that is able to prevent welding defects, while improving rebound performance.

SUMMARY OF THE INVENTION

A golf club head according to the present invention includes a head body having a crown portion and a sole portion, and having an opening surrounded by the crown portion and the sole portion, and a face member closing the opening of the head body, the face member being formed in a cup shape having a planar face portion and a peripheral portion extending from a periphery of the face portion, the peripheral portion having a thick portion configured to join to an end face of the opening of the head body, and a connecting portion connecting the thick portion and the face portion, and the connecting portion including a thin portion whose thickness is thinner than the thick portion.

In the golf club head, a configuration can be adopted in which at least part of the connecting portion has a base end portion connecting the thin portion and the face portion, and a thickness of the base end portion is smaller than the thickness of the thick portion.

In the golf club head, a configuration can be adopted in which at least part of the connecting portion has a base end portion connecting the thin portion and the face portion, and a thickness of the base end portion is larger than the thickness of the thick portion.

In the golf club head, a configuration can be adopted in which the thickness of the base end portion is larger than the thickness of the thin portion.

In the golf club head, the base end portion can be formed in a range of 20 mm from a face center in a toe-heel direction.

In the golf club head, the connecting portion can further include, between the thick portion and the thin portion, a transition portion whose thickness becomes incrementally thinner proceeding toward the thin portion from the thick portion.

In the golf club head, a length of the connecting portion in a face-back direction can be constituted to be longer than a length of the thick portion in the face-back direction.

In the golf club head, a length of the peripheral portion in the face-back direction can be set to greater than or equal to 18 mm.

With the golf club head according to the present invention, welding defects can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a golf club head according to an embodiment.

FIG. 2 is a plan view of the golf club head of FIG. 1 in a reference state.

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

FIG. 4A is a diagram illustrating a boundary of a face portion.

FIG. 4B is a diagram illustrating the boundary of the face portion.

FIG. 5 is an exploded perspective view of the head.

FIG. 6 is a partially enlarged view of FIG. 3.

FIG. 7 is a cross-sectional view showing another example of FIG. 6.

FIG. 8 is a cross-sectional view showing another example of FIG. 6.

FIG. 9 is a cross-sectional view showing another example of FIG. 6.

FIG. 10 is a plan view of the golf club head of FIG. 1 in the reference state for describing a center range.

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.

1. Overview of Golf Club Head

FIG. 1 is a perspective view of this golf club head, FIG. 2 is a plan view of the head in a reference state, and FIG. 3 is a cross-sectional view along line A-A in FIG. 2. As shown in FIGS. 1 to 3, this golf club head (hereinafter, may be referred to simply 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 can be applied to golf club heads such as drivers, utilities (hybrids), and fairway woods.

The face portion 1 has a face surface that 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, in addition to 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. As shown in FIG. 3, in the present embodiment, a recessed portion 31 for attaching a weight member (illustration omitted) is formed in 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 a shaft (illustration omitted) of the golf club is inserted, and that is formed in a cylindrical shape extending inside the head. 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 FIG. 2, 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 plane P1 will be referred to as a reference perpendicular plane. Also, as shown in FIG. 2, the direction of the line of intersection between the reference perpendicular plane P1 and the ground will be referred to as a toe-heel direction, and the direction that is perpendicular to this toe-heel direction and parallel to the ground will be referred to as a face-back direction. Also, the direction that is orthogonal to the toe-heel direction and the face-back direction may be referred to as an 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, then 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. 4A, 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 outer side of the face from the sweet spot side, as shown in FIG. 4B, 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.

The head 100 can, for example, be formed with a titanium alloy (Ti-6Al-4V, Ti-8Al-1Mo-1V, etc.) having a specific gravity of substantially about 4.3 to 4.5. 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.

The volume of this golf club head 100 is desirably from 90 cm³ to 470 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. 5, 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 1. This head main body 101 has an opening 18 surrounded by the crown portion 2 and the sole portion 3, and the face member 102 is attached so as to close this opening 18. That is, the end face of the peripheral portion 15 of the face member 102 is butted against the 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.

Note that the cross-section of FIG. 3 is a cross-section in the face-back direction passing through a face center. Hereinafter, the plane prescribing this cross-section will be referred to as a center reference plane. The face center can be defined as follows. First, an arbitrary point Po is determined generally in a vicinity of the center 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 thereinafter 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 repetition 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.

3. Structure in Vicinity of Peripheral Portion of Face Member

Next, the structure of the peripheral portion 15 of the face member 102 will be described, with reference also to FIG. 6. FIG. 6 is a partially enlarged view of the face member in the vicinity of the crown portion in FIG. 3. As shown in this diagram, a thick portion 151 is formed in the back-side end portion of the peripheral portion 15, or in other words, the end portion joined to the crown portion 2. The face-side end portion of this thick portion 151 has a transition portion 152 whose thickness incrementally decreases proceeding toward the face side, and the face-side end portion of this transition portion 152 is connected to the face portion 1 by a thin portion 153. The thickness of the thin portion 153 is the same as the thickness of the face-side end portion of the transition portion 152, generally throughout an entirety thereof.

A thickness t1 of the thick portion 151 can, for example, be set from 0.8 to 1.5 mm, and is preferably from 1.0 to 1.4 mm. Also, a thickness t2 of the thin portion 153 need only be thinner than the thick portion 151, and can, for example, be set from 0.4 to 1.4 mm, and is preferably from 0.6 to 1.0 mm. For example, the thickness t1 of the thick portion 151 can be set to 1.2 mm and the thickness t2 of the thin portion 153 can be set to 0.7 mm.

A length d1 of the thick portion 151 in the face-back direction can, for example, be set from 1 to 5 mm. This length d1 is a length prescribed on the abovementioned center reference plane with the head 100 in the reference state, and is the length on the inner wall surface side of the thick portion 151. Note that the length d1 of the thick portion 151 in the face-back direction is shorter than the total length of the transition portion 152 and the thin portion 153 in the face-back direction. An increase in the weight of the peripheral portion 15 can thereby be suppressed. Note that in the case where the thickness t1 of the thick portion 151 is measured at multiple points, the smallest measurement value of those measured is taken as the thickness t1. The measurement method is also generally the same for the thickness t2, and in the case where the thickness t2 is measured at multiple points, the smallest measurement value of those measured is taken as the thickness t2.

Also, a length d2 of the peripheral portion 15 in the face-back direction is, for example, preferably greater than or equal to 5 mm, more preferably greater than or equal to 15 mm, particularly preferably greater than or equal to 18 mm, and most preferably greater than or equal to 22 mm. On the other hand, although not particularly limited, the upper limit of the length d2 is preferably less than or equal 28 mm, and more preferably less than or equal to 26 mm. Here, the length d2 is a length prescribed on the center reference plane with the head 100 in the reference state, and is taken as the length from the boundary (e.g., ridgeline) between the face portion 1 and the peripheral portion 15 to the end portion of the outer surface of the thick portion 151.

Note that the thick portion 151, the transition portion 152 and the thin portion 153 are formed to span the entire circumference of the peripheral portion 15 including not only the crown portion 2 side but also the sole portion 3 side.

As shown in FIG. 6, a thick portion 51 is also formed in the end portion on the head body 101 side that is joined to the thick portion 151, that is, on the periphery of the opening 18. The thickness of this thick portion 51 and a length d3 in the face-back direction can be configured to be the same as the thick portion 151 of the peripheral portion 15, including the measurement method. Note that an end face 159 on the back side of the thick portion 151 of the peripheral portion 15 and an end face 52 on the face side of the thick portion 51 of the head body 101 extend generally parallel to the face portion 1 in the reference state.

4. 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. Such a head main body 101 and face member 102 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. Also, in the case of forming the face member 102 using a rolled material, the pre-processing plate of the face member 102 is processed such that the rolling direction substantially coincides with the direction from an upper portion on the toe side of the face portion 1 to a lower portion on the heel side.

The golf club head 100 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.

5. Features

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

(1) An advantage of a cup face structure such as the above is that the rebound performance of the head increases, but when the peripheral portion 15 has a large thickness, the rigidity thereof increases, and there is a risk that an improvement in the rebound performance will conversely not be readily achieved. However, when the thickness of the peripheral portion 15 is reduced, there is a risk that welding defects will occur when welding the peripheral portion 15 to the end face of the opening 18 of the head body 101, resulting in holes opening up in the peripheral portion 15 or the peripheral portion 15 being greatly deformed. In view of this, in the present embodiment, a thick portion 151 having a large thickness is formed in the back-side end portion of the peripheral portion 15, and the heat capacity is increased. Thus, welding defects can be prevented from occurring. Also, since the thickness of the thin portion 153 between the thick portion 151 and the face portion 1 is thinner than the thick portion 151, an increase in the rigidity of the peripheral portion 15 can be suppressed. The rebound performance of the head can thereby be improved.

(2) A transition portion 152 whose thickness incrementally decreases is formed between the thick portion 151 and the thin portion 153. For example, when the thick portion 151 and the thin portion 153 are directly connected without providing the transition portion 152, a sharp step is formed therebetween. When such a step is formed, stress is concentrated when the ball is hit, and there is a risk that damage such as cracking will occur. In view of this, in the present embodiment, concentration of stress is suppressed by providing the transition portion 152.

(3) The inventors of the instant invention discovered through diligent research that a place (e.g., about 15 mm) on the crown portion that is at a predetermined distance from the face portion 1 flexes the most readily when the ball is hit, depending also on the type of club. When the joining portion of the head body 101 and the peripheral portion 15 is located near this place, there is a risk that the rebound performance will be affected, since the joining portion has a large thickness. As such, when the length d2 of the peripheral portion 15 is, as described above, greater than or equal to 5 mm and less than 12 mm or greater than or equal to 18 mm less than 22 mm, for example, the joining place will be provided so as to avoid the part that flexes the most readily, and a decrease in rebound performance can be suppressed. In particular, when the length d2 is greater than or equal to 18 mm, the length of the peripheral portion becomes even longer, and rebound performance increases further. In this case, having a thick portion 151 and a thin portion 153 such as in the present embodiment is particularly advantageous.

Note that, in the present embodiment, the connecting portion of the present invention is constituted by the transition portion 152 and the thin portion 153.

6. Variations

Although an embodiment of the present invention has been described above, the present invention is not 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 combined as appropriate. For example, the following modifications can be made.

6-1. The mode of the peripheral portion 15 is not limited to the above embodiment, and need only at least have the thick portion 151, and be provided with the thin portion 153 having a smaller thickness than the thick portion 151 between the thick portion 151 and the face portion 1. For example, in the example shown in FIG. 7, the portion between the face portion 1 and the thick portion 151 in the peripheral portion 15 is constituted by a base end portion 154, the thin portion 153, and the transition portion 152 that are aligned in the face-back direction. Here, a thickness t4 of the base end portion 154 is thicker than a thickness t3 of the thin portion 153, and thinner than the thickness t1 of the thick portion 151. The thickness t4 of the base end portion 154 is, as shown in FIG. 7, measured at a position approximately 3 mm to the back side in the face-back direction from the abovementioned boundary Pe. For example, the thicknesses of the thick portion 151, the thin portion 153 and the base end portion 154 can be set to 1.2 mm, 0.7 mm and 0.9 mm, respectively. Note that, in this mode, the connecting portion of the present invention is constituted by the base end portion 154, the thin portion 153 and the transition portion 152.

Also, as shown in FIG. 8, the thickness of the base end portion 154 can be constituted to be larger than the thick portion 151. For example, the thicknesses of the thick portion 151, the thin portion 153 and the base end portion 154 can be set to 1.2 mm, 0.7 mm and 1.4 mm, respectively.

Alternatively, as shown in FIG. 9, the thickness can also be increased, such that the connecting portion of the face portion 1 and the peripheral portion 15, or in other words, the cross-section of the base end portion 154, will be triangular.

In the above example, a portion having a large thickness (e.g., the base end portion 154) is provided in part of the connecting portion according to the present invention, but the place and position thereof is not particularly limited. The connecting portion of the present invention can also be formed such that the thickness of a region other than the thin portion 153 at least partially increases or decreases incrementally. That is, various modes are possible with the configuration of the connecting portion according to the present invention, and the thin portion 153 need only be formed in at least part of the entire circumference of the peripheral portion 15.

The transition portion 152 is not necessarily required, and, for example, the thick portion 151 and the thin portion 153 can also be directly connected. Alternatively, a region having a larger thickness than the thin portion 153 and being substantially uniform in the face-back direction can also be provided between the thick portion 151 and the thin portion 153. In suppressing stress concentration such as described above, however, the transition portion 152 is preferably provided. The transition portion 152 can also be provided in part of the entire circumference of the peripheral portion.

6-2. The abovementioned modes of the peripheral portion 15 can also be combined. For example, the cross-sectional shape of the peripheral portion 15 can be constituted as shown in FIGS. 7 to 9, in the vicinity of the face center in the toe-heel direction, for example, such that the rebound performance does not become too high in the vicinity of the face center in the toe-heel direction. In other words, rather than providing the thin portion 153 around the entire circumference of the peripheral portion 15, the thickness can be increased in part (e.g., a portion of equivalent thickness to the thick portion 151 or a portion such as the base end portion 154), and the rebound performance can thereby be reduced. As the range in which such a cross-sectional shape is adopted, a range (hereinafter, center range) between a place 20 mm to the toe side and a place 20 mm to the heel side from the face center can be adopted, such as shown in FIG. 10, for example. On the other hand, the remaining range, or in other words, the range to the toe side and the heel side from the center range, can be formed with a cross-sectional shape having a thin portion 153 such as shown in FIG. 6. The rebound performance can thereby be improved other than in the center range.

Note that a center range in which the thickness is increased can be provided on at least one of the crown portion 2 side and the sole portion 3 side of the peripheral portion 15. Also, the length of the thick portion 151 in the face-back direction is not particularly limited, and, as in the above embodiment, the length of the thick portion 151 in the face-back direction can, in addition to being made shorter than the connecting portion (at least 153 out of 152, 153, 154), also be made longer than or equivalent to the connecting portion.

6-3. The shapes of the crown portion 2 and the sole portion 3 are not particularly limited, and various recesses and protrusions can be provided, from the viewpoint of design and structure. For example, in the above embodiment, a recessed portion 31 for attaching a weight member is provided, but this is an example of the shape of the sole portion 3, and the recessed portion 31 need not be provided.

LIST OF REFERENCE NUMERALS

• • 1 Face portion
  • 15 Peripheral portion
  • 151 Thick portion
  • 152 Transition portion
  • 153 Thin portion (portion connected to thick portion)
  • 154 Base end portion
  • 2 Crown portion
  • 3 Sole portion
  • 4 Hosel portion
  • 101 Head body
  • 102 Face member

Claims

1. A golf club head comprising:

a head body having a crown portion and a sole portion, and having an opening surrounded by the crown portion and the sole portion; and

a face member closing the opening of the head body,

wherein the face member is formed in a cup shape having a planar face portion and a peripheral portion extending from a periphery of the face portion,

the peripheral portion has:

a thick portion configured to join to an end face of the opening of the head body; and

a connecting portion connecting the thick portion and the face portion, and

the connecting portion includes a thin portion whose thickness is thinner than the thick portion.

2. The golf club head according to claim 1,

wherein at least part of the connecting portion has a base end portion connecting the thin portion and the face portion, and

a thickness of the base end portion is smaller than the thickness of the thick portion.

3. The golf club head according to claim 1,

wherein at least part of the connecting portion has a base end portion connecting the thin portion and the face portion, and

a thickness of the base end portion is larger than the thickness of the thick portion.

4. The golf club head according to claim 2, wherein the thickness of the base end portion is larger than the thickness of the thin portion.

5. The golf club head according to claim 4, wherein the base end portion is formed in a range of 20 mm from a face center in a toe-heel direction.

6. The golf club head according to claim 3, wherein the thickness of the base end portion is larger than the thickness of the thin portion.

7. The golf club head according to claim 6, wherein the base end portion is formed in a range of 20 mm from a face center in a toe-heel direction.

8. The golf club head according to claim 1, wherein the connecting portion further includes, between the thick portion and the thin portion, a transition portion whose thickness becomes incrementally thinner proceeding toward the thin portion from the thick portion.

9. The golf club head according to claim 1, wherein a length of the connecting portion in a face-back direction is longer than a length of the thick portion in the face-back direction.

10. The golf club head according to claim 1, wherein a length of the peripheral portion in the face-back direction is greater than or equal to 18 mm.